BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a combustion control apparatus for an internal combustion
engine for controlling the combustion state of an air fuel mixture in each combustion
chamber.
2. Description of the Related Art
[0002] In the past, there have been developed internal combustion engines that can selectively
switch between low temperature combustion in which the generation of soot is suppressed
by increasing the amount of burnt gas components in a combustion chamber more than
the amount of burnt gas components at the time when the amount of soot generated becomes
maximum due to the burnt gas components in the combustion chamber being increased,
and ordinary combustion in which the amount of unburnt gas components in the combustion
chamber is less than the amount of burnt gas components at the time when the amount
of soot generated becomes maximum.
[0003] In such internal combustion engines, the low temperature combustion and the ordinary
combustion are switched over based on a predetermined condition such as the operating
condition of an engine, etc. For example, a first patent document (for example, see
Japanese patent No.
3094974 (corresponding to
EP0907013 and
US5890360)) discloses an internal combustion engine in which low temperature combustion is
carried out when the operating condition of the engine is in a low load operating
range, and ordinary combustion is carried out when the engine operating condition
is in a high load operating range, but when an oxidation catalyst arranged on an exhaust
passage is not activated, ordinary combustion is performed so as to suppress the discharge
or emission of unburnt hydrocarbons even if the engine operating condition is in the
low load operating range.
[0004] In addition, in lean burn internal combustion engines that selectively switch between
the low temperature combustion and the ordinary combustion, combustion or burning
of an air fuel mixture is carried out with an air fuel ratio of a mixture in the combustion
chamber being held considerably higher than the stoichiometric air fuel ratio at the
time of ordinary combustion, whereas combustion or burning is carried out with the
air fuel ratio of the mixture in the combustion chamber being held relatively low
at the time of low temperature combustion in which the amount of burnt gas components
in the mixture is large with a small proportion of air.
[0005] On the other hand, when a required load (i.e., an engine load required by a driver)
in the internal combustion engine is changed such as upon acceleration or deceleration
of a vehicle on which the engine is mounted, the amount of fuel to be injected into
the combustion chamber (hereinafter referred to as "actual fuel injection amount")
is increased or decreased to an amount of injection fuel corresponding to the required
load (hereinafter referred to as "required fuel injection amount"), but when the actual
fuel injection amount increases rapidly, there will take place deterioration of driveability
resulting from an abrupt increase in the engine torque, generation of combustion noise
and misfiring, etc.. Accordingly, in internal combustion engine, the actual fuel injection
amount is generally controlled to change gradually even upon a change in the required
load.
[0006] Moreover, the combustion of a mixture in the combustion chamber, when carried out
at a low air fuel ratio thereof such as at the time of low temperature combustion,
is liable to become unstable in comparison with the case where the combustion of a
mixture in the combustion chamber is carried out at a high air fuel ratio of the mixture
such as at the time of ordinary combustion, and hence it is necessary to more accurately
control the air fuel ratio of the mixture in the combustion chamber so as to obtain
stable combustion. Therefore, in case where the required load of the engine is changed
at the time of low temperature combustion, if the actual fuel injection amount is
caused to change at the same change rate or speed as that at which combustion is carried
out at a high air fuel ratio, there will be a fear that the combustion might become
unstable, thus increasing the amount of smoke to be discharged or emitted from the
engine or inviting misfiring.
[0007] Accordingly, in the past, in internal combustion engines that selectively switch
between the combustion of a mixture at an air fuel ratio thereof in the combustion
chamber higher than a predetermined air fuel ratio (hereinafter referred to as "high
air fuel ratio combustion") and the combustion of a mixture in the combustion chamber
at an air fuel ratio thereof lower than or equal to the predetermined air fuel ratio
(hereinafter referred to as "low air fuel ratio combustion"), as in the internal combustion
engines that selectively switches between the ordinary combustion and the low temperature
combustion, when the required load is changed to increase or decrease the actual fuel
injection amount such as at the time of acceleration or deceleration, fuel injection
is controlled in such a manner that the change rate or speed, at which the actual
fuel injection amount is gradually changed at the time of low air fuel ratio combustion,
is made slower than a change rate or speed at which the actual fuel injection amount
is gradually changed at the time of high air fuel ratio combustion (for example, see
Japanese patent No.
3336968 (corresponding to
EP99113774.6 and
US6209515)).
[0008] In this connection, note that there are following documents that are relevant to
the present invention.
[0013] In the low air fuel ratio combustion, it is necessary to reduce the amount of air
in the combustion chamber as well as to control the air fuel ratio of a mixture in
the combustion chamber in a more accurate manner. Thus, an operating range of the
engine in which the low air fuel ratio combustion can be carried out in a stable manner
is limited to a low load operating range. Therefore, in the internal combustion engines
that selectively switch between high air fuel ratio combustion and low air fuel ratio
combustion, as stated above, an operating range of the engine in which low air fuel
ratio combustion is carried out is decided to be a low load operating range or a part
thereof, and hence a high load operating range becomes an operating range of the engine
in which high air fuel ratio combustion is carried out. Also, in the past, the high
air fuel ratio combustion and the low air fuel ratio combustion are selectively switched
over based on the number of revolutions of the engine and the actual fuel injection
amount. That is, the combustion state in the combustion chamber is switched into the
low air fuel ratio combustion when the actual fuel injection amount becomes an amount
of injection fuel corresponding to the low load operating range, whereas the combustion
state in the combustion chamber is switched into the high air fuel ratio combustion
when the actual fuel injection amount becomes an amount of injection fuel corresponding
to the high load operating range.
[0014] However, when a request for accelerating the vehicle to speeds corresponding to the
high load operating range, in which high air fuel ratio combustion is performed, is
made while low air fuel ratio combustion is being carried out in the low load operating
range for example, the rate of increase of the actual fuel injection amount is made
slower at the time of low air fuel ratio combustion than that at the time of high
air fuel ratio combustion so as to perform stable combustion, as stated above. As
a consequence, it takes a certain period of time for the actual fuel injection amount
to reach a threshold for switching the combustion in the combustion chamber between
the low air fuel ratio combustion and the high air fuel ratio combustion. That is,
it takes time until the combustion state is switched into the high fuel ratio combustion.
Accordingly, there will be a fear that the time needed for the actual fuel injection
amount to reach the required fuel injection amount might be increased, thus impairing
the acceleration performance of the vehicle.
SUMMARY OF THE INVENTION
[0015] In view of the above, the present invention is intended to provide, in an internal
combustion engine which selectively switches between high air fuel ratio combustion
and low air fuel ratio combustion, a technique which is capable of obtaining stable
combustion as well as better acceleration or deceleration performance of the engine.
[0016] In order to solve the above-mentioned problems, the present invention adopted the
following solution. That is, according to the present invention, in a combustion control
apparatus for an internal combustion engine in which a combustion state in a combustion
chamber is selectively switched between high air fuel ratio combustion and low air
fuel ratio combustion, a switching determination parameter for switching the combustion
state from the low air fuel ratio combustion into the high air fuel ratio combustion
is made to be a required fuel injection amount corresponding to a required load of
the engine, and a switching determination parameter for switching the combustion state
from the high air fuel ratio combustion into the low air fuel ratio combustion is
made to be an actual fuel injection amount which is an amount of fuel to be injected
into the combustion chamber each time fuel injection is performed.
[0017] More specifically, according to the present invention, there is provided a combustion
control apparatus for an internal combustion engine in which a combustion state in
a combustion chamber is selectively switched between high air fuel ratio combustion
in which combustion is performed at an air fuel ratio of a mixture in the combustion
chamber higher than a predetermined air fuel ratio, and low air fuel ratio combustion
in which combustion is performed at an air fuel ratio of the mixture in the combustion
chamber lower than or equal to the predetermined air fuel ratio, characterized in
that
a fuel injection control part is provided which includes a required fuel injection
amount calculation part that calculates a required fuel injection amount which is
an amount of injection fuel corresponding to a required load of the engine and an
actual fuel injection amount calculation part that calculates an actual fuel injection
amount which is an amount of fuel to be injected into the combustion chamber each
time fuel injection is performed, and the fuel injection control part gradually changes,
upon change of the required load, the actual fuel injection amount to the required
fuel injection amount, and controls the change speed of the actual fuel injection
amount, which is gradually changed when the combustion state is in the low air fuel
ratio combustion, to be more gradual than that when the combustion state is in the
high air fuel ratio combustion,
wherein a switching determination parameter for switching the combustion state
from the low air fuel ratio combustion into the high air fuel ratio combustion is
made to be the required fuel injection amount, and a switching determination parameter
for switching the combustion state from the high air fuel ratio combustion into the
low air fuel ratio combustion is made to be the actual fuel injection amount.
[0018] Here, note that the predetermined air fuel ratio is a relatively low air fuel ratio
in which when combustion is performed at an air fuel ratio lower than or equal to
the predetermined air fuel ratio, combustion is liable to become unstable due to a
small amount of air, and hence it is necessary to more accurately control the amount
of air and the amount of fuel supplied for the combustion so as to provide good combustion.
One example of the predetermined air fuel ratio is an upper limit of the air fuel
ratio at the time of low temperature combustion. Another example may be a value between
from the neighborhood of the stoichiometric air fuel ratio up to about an air fuel
ratio (A/F) of 25. Therefore, the low air fuel ratio combustion is not limited to
combustion at an air fuel ratio richer than the stoichiometric air fuel ratio.
[0019] As described above, in the past, even when the driver of a vehicle makes a request
for acceleration or deceleration of the vehicle. the actual fuel injection amount
is controlled so that it does not become the required fuel injection amount at once
but is increased or decreased gradually. In this case, the actual fuel injection amount
is changed more gradual at the time of low air fuel ratio combustion than at the time
of high air fuel ratio combustion. Stated in other words, the actual fuel injection
amount changes more quickly at the time of high air fuel ratio combustion than at
the time of low air fuel ratio combustion.
[0020] Here, note that in case where the operating condition of the engine is in an operating
range in which the low air fuel ratio combustion is performed (hereinafter referred
to as "low air fuel ratio combustion range") and the combustion state is in the low
air fuel ratio combustion, when an request is made for acceleration or deceleration
to an operating range in which the high air fuel ratio combustion is performed (hereinafter
referred to as "high air fuel ratio combustion range"), the required fuel injection
amount immediately becomes an injection fuel amount corresponding to the high air
fuel ratio combustion range. At this time, in the present invention, a parameter used
when the combustion state is switched from the low air fuel ratio combustion into
the high air fuel ratio combustion is the required fuel injection amount, so the combustion
state is switched into the high air fuel ratio combustion at once. Thus, the actual
fuel injection amount changes more quickly, making it possible to obtain better acceleration
or deceleration performance.
[0021] On the other hand, in the present invention, a parameter used when the combustion
state is switched from the high air fuel ratio combustion into the low air fuel ratio
combustion is the actual fuel injection amount. Accordingly, in case where the operating
condition of the engine is in the high air fuel ratio combustion range and the combustion
state is in the high air fuel ratio combustion, when a request is made for acceleration
or deceleration to the low air fuel ratio combustion range, the combustion state is
switched into the low air fuel ratio combustion after the actual fuel injection amount
has become a fuel injection amount corresponding to the low air fuel ratio combustion
range, namely, after the operating condition of the engine has become the low air
fuel ratio combustion range. As a result, the combustion state is by no means switched
into the low air fuel ratio combustion when the operating condition of the engine
is in an operating range in which the low air fuel ratio combustion is difficult to
be performed, and hence more stable low air fuel ratio combustion can be carried out.
[0022] Preferably, in the present invention, in case where the combustion state is switched
into the high air fuel ratio combustion when the operating condition of the engine
is in a high load operating range, and switched into the low air fuel ratio combustion
when the operating condition of the engine is in a low load operating range, a switching
determination parameter for switching the combustion state at the time of a transient
operation, such as for example acceleration, from the low load operating range into
the high load operating range may be made to be the required fuel injection amount,
and a switching determination parameter for switching the combustion state at the
time of a transient operation, such as for example deceleration, from the high load
operating range into the low load operating range may be made to be the actual fuel
injection amount.
[0023] According to such an arrangement, in case where the operating condition of the engine
is in the low load operating range and the combustion state is in the low air fuel
ratio combustion, the combustion state is switched into the high air fuel ratio combustion
at once when a request is made for acceleration to the high load operating range in
which the high air fuel ratio combustion is performed. As a result, the actual fuel
injection amount changes more quickly, and better acceleration performance can be
obtained.
[0024] On the other hand, in case where the operating condition of the engine is in the
high load operating range and the combustion state is in the high air fuel ratio combustion,
when a request is made for deceleration to the low load operating range in which the
low air fuel ratio combustion is performed, the combustion state is switched into
the low air fuel ratio combustion after the operating condition of the engine has
become the low air fuel ratio combustion range. As a result, more stable low air fuel
ratio combustion can be carried out.
[0025] Preferably, in the present invention, the required fuel injection amount calculation
part may calculate the required fuel injection amount based on the number of revolutions
of the engine and the degree of opening of an accelerator pedal.
[0026] Preferably, in the present invention, in case where the fuel injection control part
sets a variable fuel amount, which is a fuel injection amount able to be increased
or decreased each time fuel injection is carried out when the actual fuel injection
amount is gradually changed, separately for the low temperature combustion and the
ordinary combustion, respectively, the variable fuel amount is separately set for
the high air fuel ratio combustion and the low air fuel ratio combustion, respectively,
and the fuel injection control part sets a variable fuel amount at the time of low
air fuel ratio combustion to be smaller than a variable fuel amount at the time of
high air fuel ratio combustion.
[0027] By properly setting the variable fuel amount, the actual fuel injection amount can
be controlled to change gradually even when the required load is changed. Also, by
setting the variable fuel amount at the time of low air fuel ratio combustion to be
smaller than the variable fuel amount at the time of high air fuel ratio combustion,
it is possible to control the change rate or speed of the actual fuel injection amount,
which is gradually changed at the time of low air fuel ratio combustion, to be more
gradual than the change speed of the actual fuel injection amount, which is gradually
changed at the time of high air fuel ratio combustion. Accordingly, the air fuel ratio
of the mixture in the combustion chamber can be controlled more accurately at the
time of low air fuel ratio combustion, thereby making it possible to suppress an increase
in the amount of smoke to be emitted and generation of misfiring.
[0028] Preferably, in the present invention, the combustion state in the combustion chamber
is switched into the high air fuel ratio combustion when the operating condition of
the engine is in the high load operating range, and switched into the low air fuel
ratio combustion when the operating condition of the engine is in the low load operating
range, as stated above. In this case, when the required load increases, the actual
fuel injection amount calculation part compares an actual fuel injection amount, which
was calculated upon the last fuel injection and which is added by the variable fuel
amount, with the required fuel injection amount, and calculates the value of the small
one as a current actual fuel injection amount, whereas when the required load decreases,
the actual fuel injection amount calculation part compares the actual fuel injection
amount, which was calculated upon the last fuel injection and which is subtracted
by the variable fuel amount, with the required fuel injection amount, and calculates
the value of the greater one as a current actual fuel injection amount.
[0029] By calculating the actual fuel injection amount each time fuel injection is performed
in this manner, when the required load increases such as upon acceleration for example,
the actual fuel injection amount is successively increased by the variable fuel amount
each time fuel injection is performed until it reaches the required fuel injection
amount, whereas when the required load decreases such as upon deceleration for example,
the actual fuel injection amount is successively decreased by the variable fuel amount
each time fuel injection is performed until it reaches the required fuel injection
amount.
[0030] Further, in the present invention, it is preferred that when the actual fuel injection
amount upon each fuel injection is calculated in the above manner, a comparison is
made between the actual fuel injection amount calculated upon each fuel injection
and the required fuel injection amount, and the value of the greater one may be made
as a switching determination parameter for switching the combustion state.
[0031] By determining the switching determination parameter in this manner, a switching
determination parameter for switching the combustion state at the time of a transient
operation from the low load operating range into the high load operating range can
be made to be the required fuel injection amount, and a switching determination parameter
for switching the combustion state at the time of a transient operation from the high
load operating range into the low load operating range can be made to be the actual
fuel injection amount.
[0032] In the case of a combustion control apparatus for an internal combustion engine according
to the present invention in which a combustion state is selectively switched between
low temperature combustion and ordinary combustion, the low air fuel ratio combustion
may be the low temperature combustion, and the high air fuel ratio combustion may
be the ordinary combustion.
[0033] According to such an arrangement, better acceleration or deceleration performance
can be obtained, and at the same time more stable low temperature combustion can be
carried out, thus making it possible to suppress the generation of soot. Here, note
that in the case of such an arrangement, it is preferred that the predetermined air
fuel ratio be an upper limit of the air fuel ratio at the time of low temperature
combustion.
[0034] Preferably, in the present invention, in case where the low air fuel ratio combustion
is made to be the low temperature combustion, and the high air fuel ratio combustion
is made to be the ordinary combustion, an operating range of the engine, in which
the combustion state is controlled to be the low temperature combustion, is made as
a low temperature combustion range, and an operating range of the engine, in which
the combustion state is controlled to be the ordinary combustion, is made as an ordinary
combustion range. In this case, by using the required fuel injection amount as a switching
determination parameter for switching the combustion state from the low temperature
combustion into the ordinary combustion, the combustion state is switched from the
low temperature combustion into the ordinary combustion when the required fuel injection
amount becomes an fuel injection amount corresponding to a threshold between the low
temperature combustion range and the ordinary combustion range.
[0035] Preferably, in this case, by using the actual fuel injection amount as a switching
determination parameter for switching the combustion state from the ordinary combustion
into the low temperature combustion, the combustion state is switched from the ordinary
combustion into the low temperature combustion when the actual fuel injection amount
becomes a fuel injection amount corresponding to a threshold between the low temperature
combustion range and the ordinary combustion range.
[0036] In a preferred form of the present invention, in an internal combustion engine with
an exhaust gas purification catalyst, which has a property of gradually accumulating
sulfur components in an exhaust gas, disposed on an exhaust passage, in order to raise
the temperature of the exhaust gas purification catalyst as well as to make an ambient
atmosphere a rich one for the release of the accumulated sulfur components therefrom,
combustion is performed at a low air fuel ratio of a mixture in a combustion chamber
to lower the air fuel ratio of the exhaust gas, and a reducing agent is further added
to the exhaust passage at a location upstream of the exhaust gas purification catalyst
(hereinafter this control is referred to as "sulfur poisoning regeneration control").
In such a case, the low air fuel ratio combustion may be combustion in the combustion
chamber at the time of the sulfur poisoning regeneration control, or the low temperature
combustion may be combustion in the combustion chamber at the time of the sulfur poisoning
regeneration control,
[0037] The above and other objects, features and advantages of the present invention will
become more readily apparent to those skilled in the art from the following detailed
description of preferred embodiments of the present invention taken in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038]
Fig. 1 is a view showing the schematic construction of an internal combustion engine
and its combustion control apparatus according to the present invention.
Fig. 2 is a view showing a low temperature combustion range and an ordinary combustion
range according to a first embodiment of the present invention.
Fig. 3 is a view explaining the switching control of the combustion state carried
out by the combustion control apparatus for an internal combustion engine according
to the first embodiment of the present invention.
Fig. 4 is a flow chart showing a combustion state switching control routine executed
by the combustion control apparatus for an internal combustion engine according to
the first embodiment of the present invention.
Fig. 5 is a view showing a low temperature combustion range, a high EGR combustion
range and an ordinary combustion range according to a second embodiment of the present
invention.
Fig. 6 is a view showing the flow of signals around an ECU according to the first
embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Hereinafter, preferred embodiments of a combustion control apparatus for an internal
combustion engine according to the present invention will be described in detail while
referring to the accompanying drawings. Here, reference will be made to the case where
the present invention is applied to a diesel engine.
<FIRST EMBODIMENT>
[0040] Fig. 1 is a view that illustrates the schematic construction of an internal combustion
engine and its combustion control apparatus according to a first embodiment of the
present invention.
[0041] The internal combustion engine (hereinafter also referred to simply as an engine),
generally designated at reference numeral 1 as illustrated in Fig. 1, is a multi-cylinder
diesel engine having four cylinders 2. The engine 1 is provided with fuel injection
valves 3, one for each cylinder 2, for directly injecting fuel into a combustion chamber
of each cylinder 2. The respective fuel injection valves 3 are connected with an accumulator
or common rail 4 that serves to accumulate or pressurized up the fuel to a prescribed
pressure. A common rail pressure sensor 4a is mounted on the common rail 4 for generating
an electric signal corresponding to the pressure of the fuel in the common rail 4.
[0042] The common rail 4 is in communication with a fuel pump 6 through a fuel feed pipe
5. The pump 6 is driven to operate by the rotational torque of an output shaft or
crankshaft of the engine 1 which serves as a drive source, and a pump pulley 6a mounted
on an input shaft of the fuel pump 6 is operatively connected through a belt 7 with
a crankshaft pulley 1 a mounted on the crankshaft of the engine 1.
[0043] In the fuel injection system as constructed in this manner, the fuel supplied to
the common rail 4 by the fuel pump 6 through the fuel feed pipe 5 is accumulated or
pressurized up to a predetermined pressure in the common rail 4 and distributed to
the fuel injection valves 3 of the respective cylinders 2. Thereafter, when a drive
current is applied to the fuel injection valves 3, the fuel injection valves 3 are
operated to open so that fuel is injected from the fuel injection valves 3 into the
corresponding cylinders 2, respectively.
[0044] An intake manifold 18 is connected with the engine or engine proper 1 in such a manner
that it is in communication with the combustion chambers of the respective cylinders
2 through intake ports (not illustrated), respectively.
[0045] The intake manifold 18 is connected with an intake pipe 9, on which an air cleaner
box 10, an air flow meter 11 for generating an electric signal corresponding to the
mass of the intake air flowing in the intake pipe 9, a compressor housing 15a of a
centrifugal supercharger (turbocharger) 15, an intercooler 16 and a throttle valve
13 are sequentially mounted in this order from an upstream side of the intake pipe
9. A throttle actuator 14 for driving the throttle valve 13 to open and close is mounted
on the throttle valve 13, so that the flow rate of the intake air flowing in the intake
pipe 9 is adjusted in accordance with the opening and closing movement of the throttle
valve 13.
[0046] On the other hand, an exhaust manifold 18 is connected with the engine or engine
proper 1 in such a manner that it is in communication with the combustion chambers
of the respective cylinders 2 through exhaust ports 30, respectively.
[0047] The exhaust manifold 18 is connected with a turbine housing 15b of the centrifugal
supercharger 15. Also, the turbine housing 15b is connected with an exhaust pipe 19.
An exhaust gas purification catalyst 20 is disposed on the exhaust pipe 19 which is
connected with an unillustrated muffler at a location downstream of the exhaust gas
purification catalyst 20.
[0048] In addition, an exhaust gas recirculation device 40 is attached to the internal combustion
engine 1 for recirculating a part of the exhaust gas flowing in the exhaust system
of the engine 1 into the intake system. The exhaust gas recirculation device 40 includes
an exhaust gas recirculation passage (EGR passage) 25 formed to extend from the exhaust
manifold 18 through the interior of cylinder heads to a joint portion of the intake
manifold 18, an exhaust gas recirculation flow regulation valve (EGR valve ) 26 in
the form of an electromagnetic valve or the like for adjusting the flow rate of the
exhaust gas flowing in the EGR passage 25 (hereinafter referred to as EGR gas) in
proportion to the magnitude of a voltage applied thereto, and an EGR cooler 27 arranged
in the EGR passage 25 at a location upstream of the EGR valve 26 for cooling the EGR
gas flowing in the EGR passage 25.
[0049] In the exhaust gas recirculation device 40 constructed in this manner, when the EGR
valve 26 is opened, a part of the exhaust gas flowing in the exhaust manifold 18 passes
through the EGR passage 25 and flows into the joint portion of the intake manifold
18 while being cooled by the EGR cooler 27. The EGR gas flowing into the intake manifold
18 forms into an air fuel mixture while being mixed with fresh air coming from the
upstream side of the intake manifold 18, and is distributed to the combustion chambers
of each cylinder 2.
[0050] Here, note that when the EGR gas containing inert gas components, which do not combust
or burn on their own and which have heat absorbing or endothermic property as in the
case of water (H
2O), carbon dioxide (CO
2) or the like. Therefore, when it is mixed with an air fuel mixture, the combustion
temperature of the mixture is lowered, thus suppressing the amount of generation of
nitrogen oxides (NOx).
[0051] An electronic control unit (ECU) 35 for controlling the engine 1 is provided in conjunction
with the engine 1 as constructed in the above manner. This ECU 35 serves to control
the operating conditions of the engine 1 in accordance with the operating state of
the vehicle and driver's requirements.
[0052] Various kinds of sensors such as the common rail pressure sensor 4a, the air flow
meter 11, an intake pipe pressure sensor 17 for sensing the pressure of intake air
in the intake pipe 9, a crank position sensor 33 for sensing the rotational angle
or position of the crankshaft, an accelerator opening sensor 36 for sensing the degree
of opening or depression of an accelerator pedal, etc., are connected to the ECU 35
through electric wiring, so that the output signals of these sensors are input to
the ECU 35.
[0053] On the other hand, the fuel injection valves 3, the throttle actuator 14, the EGR
valve 26 and the like are also connected to the ECU 35 through electric wiring, so
that they can be controlled by the ECU 35.
[0054] The ECU 35 includes a CPU, a ROM, a RAM and the like, and calculates, for example,
the number of revolutions of the engine based on time intervals between pulses in
the output signal of the crank position sensor 33, as well as the amount of the intake
air supplied to each combustion chamber based on the output signals of the air flow
meter 11 and the intake pipe pressure sensor 17.
[0055] Here, note that the internal combustion engine 1 according to this embodiment operates
to selectively switch between a low temperature combustion state (corresponding to
the low air fuel ratio combustion according to the present invention), in which the
amount of generation of soot is suppressed by making, under the control of the exhaust
gas recirculation device 40, the amount of the EGR gas (corresponding to the burnt
gas components in the present invention) supplied to each combustion chamber greater
than an amount of EGR gas at the time when the amount of generation of soot, which
increases in accordance with the increasing amount of the EGR gas supplied to each
combustion chamber, becomes maximum in a state of fuel injection timing, at which
fuel is injected into each combustion chamber, being fixed, and an ordinary combustion
state (corresponding to the high air fuel ratio combustion according to the present
invention), in which the EGR gas in each combustion chamber is less than the above-mentioned
amount of EGR gas with which the amount of generation of soot becomes maximum.
[0056] Since combustion is liable to become unstable in the low temperature combustion because
of the amount of the EGR gas supplied to each combustion chamber being increased so
as to reduce the amount of intake air therein, it is necessary to control the air
fuel ratio of the mixture in each combustion chamber in a more accurate manner. Therefore,
an operating range of the engine in which low temperature combustion can be performed
in a stable manner is limited to the low load operating range. Accordingly, in the
internal combustion engine 1 according to this embodiment, as shown in Fig. 2, a first
operating range of the engine in which the low temperature combustion is performed
(hereinafter referred to as a low temperature combustion range) and a second operating
range of the engine in which the ordinary combustion is performed (hereinafter referred
to as an ordinary combustion range) are respectively set based on the number of revolutions
and the engine load, and the low temperature combustion range is set in the low load
operating range.
[0057] Moreover, at the time of ordinary combustion, combustion is carried out at an air
fuel ratio of the mixture in each combustion chamber considerably higher than the
stoichiometric air fuel ratio, whereas at the time of low temperature combustion in
which the amount of EGR gas is large and the amount of intake air is small, as stated
above, combustion is carried out at an air fuel ratio of the mixture in each combustion
chamber lower than that at the time of ordinary combustion.
[0058] Next, reference will be made to the fuel injection control in the internal combustion
engine 1 according to this embodiment.
[0059] In the internal combustion engine 1 according to this embodiment, when the required
load of the engine is changed as in the case of acceleration or deceleration of the
vehicle, the actual fuel injection amount is controlled to change gradually to reach
the required fuel injection amount so as to avoid generation of defects such as deterioration
of driveability due to a rapid change in the engine torque, combustion noise and misfiring,
etc..
[0060] Further, a variable amount of injection fuel (hereinafter referred to as a variable
fuel amount), which is able to be increased or decreased each time fuel injection
is carried out, is set separately for the low temperature combustion and the ordinary
combustion, so that the change of the actual fuel injection amount becomes more gradual
at the time of the low temperature combustion than at the time of the ordinary combustion.
That is, this variable fuel amount is set smaller in the low temperature combustion
than in the ordinary combustion, and the amount of injection fuel is controlled in
a different manner at the time of low temperature combustion and at the time of ordinary
combustion, based on the required fuel injection amount, the variable fuel amount,
the number of revolutions of the engine, etc.
[0061] The reason for this is as follows. In the low temperature combustion, combustion
is performed at an air fuel ratio of the mixture in each combustion chamber lower
than that in the ordinary combustion, as stated above, and hence is liable to become
unstable as compared with that at the time of ordinary combustion. Thus, there is
a fear that if the actual fuel injection amount is changed at the same speed or rate
as that at the time of ordinary combustion, the amount of smoke to be emitted from
the engine might be increased and/or misfiring might be induced.
[0062] Now, reference will be made to the combustion state switching control operation of
the combustion control apparatus for an internal combustion engine according to this
embodiment while referring to Fig. 3.
[0063] When a request is made by the driver for accelerating the engine speed up to the
ordinary combustion range during the low temperature combustion of the engine so that
the degree of opening of the accelerator pedal detected by the accelerator opening
sensor 36 increases, the required fuel injection amount eqgov inevitably increases
at once, as shown by the fuel injection amount indicated at a solid line in Fig. 3.
As referred to above, however, the actual fuel injection amount eqfin does not immediately
become the required fuel injection amount eqgov but gradually increases, as shown
by the fuel injection amount indicated at a broken line in Fig. 3.
[0064] In case where the actual fuel injection amount eqfin is used as a determination parameter
for switching the combustion state in each combustion chamber from the low temperature
combustion into the ordinary combustion, the combustion state is switched from the
low temperature combustion into the ordinary combustion when the actual fuel injection
amount eqfin becomes a fuel injection amount (i.e., indicated by an alternate long
and short dash line in Fig. 3) corresponding to a threshold between the low temperature
combustion range and the ordinary combustion range, as shown by the combustion state
indicated at a broken line in Fig. 3. In contrast to this, in the combustion switching
control according to this embodiment, the required fuel injection amount eqgov is
used as a determination parameter for switching the combustion state in each combustion
chamber from the low temperature combustion into the ordinary combustion. In this
case, the combustion state in each combustion chamber is switched from the low temperature
combustion into the ordinary combustion when the required fuel injection amount eqgov
becomes the fuel injection amount corresponding to the threshold between the low temperature
combustion range and the ordinary combustion range, as shown by the combustion state
indicated at a solid line in Fig. 3. In other words, according to the combustion switching
control of this embodiment, the combustion state can be switched into the ordinary
combustion more early at the time of acceleration.
[0065] On the other hand, when the degree of opening of the accelerator pedal detected by
the accelerator opening sensor 36 decreases according to a driver's request for decelerating
the engine speed up to the low temperature combustion range while the internal combustion
engine 1 is performing the ordinary combustion, the required fuel injection amount
eqgov inevitably decreases at once. In this case, however, the actual fuel injection
amount eqfin does not become the required fuel injection amount eqgov at once but
gradually decreases, as stated above. At this time, in the combustion control apparatus
according to this embodiment, the combustion is switched from the ordinary combustion
into the low temperature combustion when the actual fuel injection amount eqfin becomes
the fuel injection amount corresponding to the threshold between the low temperature
combustion range and the ordinary combustion range.
[0066] That is, in the combustion control apparatus for an internal combustion engine according
to this embodiment, a switching determination parameter used when the combustion state
is switched from the low temperature combustion into the ordinary combustion, namely
a switching determination parameter used upon switching of the combustion state during
acceleration, is the required fuel injection amount eqgov, whereas a switching determination
parameter used when the combustion state is switched from the ordinary combustion
into the low temperature combustion, namely a switching determination parameter used
upon switching of the combustion state during deceleration is the actual fuel injection
amount eqfin.
[0067] According to such combustion switching control, at the time of acceleration, the
combustion state is switched into the ordinary combustion more early so that the actual
fuel injection amount can be increased more quickly, thereby making it possible to
provide better acceleration performance.
On the other hand, at the time of deceleration, the combustion state is switched into
the low temperature combustion after the actual fuel injection amount has become a
fuel injection amount corresponding to the low temperature combustion range, namely,
after the operating condition of the internal combustion engine 1 has been changed
into the low temperature combustion range, so that more stable low temperature combustion
can be carried out, thus making it possible to suppress the emission of smoke, misfiring
and deterioration of combustion noise.
[0068] Next, reference will be made to a combustion state switching control routine executed
by the combustion control apparatus for an internal combustion engine according to
this embodiment while referring to a flow chart shown in Fig. 4.
[0069] The flow chart in Fig. 4 illustrates the combustion state switching control routine
according to this embodiment. This combustion state switching control routine is executed
by the ECU 35 each time fuel is injected into each combustion chamber, and it is stored
in advance in the ROM of the ECU 35.
[0070] In this routine, first in step S101, the ECU 35 detects whether the current combustion
state is the low temperature combustion or the ordinary combustion. In this connection,
note that the combustion state at this time may be detected from the result of the
last execution of this routine.
[0071] Then, the routine or control flow goes to step S102 where the ECU 35 calculates the
required fuel injection amount eqgov based on the number of revolutions N of the engine
and the degree of opening D of the accelerator pedal.
[0072] Thereafter, the control flow proceeds to step S103 where the ECU 35 calculates a
variable fuel amount Δ Q corresponding to the combustion state detected in step S101,
and then it advances to step S104.
[0073] When in step S104, the degree of opening D of the accelerator pedal increases, i.e.,
when the vehicle or engine is accelerated, the ECU 35 compares an actual fuel injection
amount eqfin', which was calculated when this routine was last executed and which
is added by the variable fuel amount Δ Q calculated in step S103, with the required
fuel injection amount eqgov calculated in step S102, and calculates the value of the
small one as a current actual fuel injection amount eqfin. On the other hand, when
in step S104, the degree of opening D of the accelerator pedal decreases, i.e., when
the vehicle or engine is decelerated, the ECU 35 compares the actual fuel injection
amount eqfin', which was calculated when this routine was last executed and which
is subtracted by the variable fuel amount Δ Q calculated in step S103, with the required
fuel injection amount eqgov calculated in step S102, and calculates the value of the
greater one as a current actual fuel injection amount eqfin.
[0074] In other words, at the time of acceleration, the actual fuel injection amount eqfin
is successively increased by the variable fuel amount Δ Q each time fuel injection
is performed until it reaches the required fuel injection amount eqgov. On the other
hand, at the time of deceleration, the actual fuel injection amount eqfin is successively
decreased by the variable fuel amount Δ Q each time fuel injection is performed until
it reaches the required fuel injection amount eqgov.
[0075] Subsequently, the control flow advances to step S105 where the ECU 35 makes a comparison
between the required fuel injection amount eqgov calculated in step S102 and the actual
fuel injection amount eqfin calculated in step S104, and calculates the value of the
greater one as a determination fuel injection amount eqmdcb, which becomes a combustion
state switching determination parameter.
[0076] Then, the control flow proceeds to step S106 where the ECU 35 determines a combustion
state into which the current combustion is to be switched, based on the determination
fuel injection amount eqmdcb and the number of revolutions N of the engine calculated
in step S105, after which the control flow goes to step S107.
[0077] In step S107, the ECU 35 switches the combustion state in each combustion chamber
into the combustion state determined in step S106, and then completes the execution
of this routine.
[0078] According to this combustion state switching control routine, the determination fuel
injection amount eqmdcb at the time of acceleration becomes the required fuel injection
amount eqgov, and the determination fuel injection amount eqmdcb at the time of deceleration
becomes the actual fuel injection amount eqfin. That is, at the time of acceleration,
the combustion state is switched over by using the required fuel injection amount
eqgov as a switching determination parameter, whereas at the time of deceleration,
the combustion state is switched over by using the actual fuel injection amount eqfin
as a switching determination parameter.
[0079] Here, reference will be made to the flow of signals around the ECU 35 in this embodiment
while referring to Fig. 6. In Fig. 6, broken line arrows (1) and (2) represent the
flow of signals from the crank position sensor 33 and the accelerator opening sensor
36 to the ECU 35, respectively, and broken line arrow (3) represents the flow of a
signal from the ECU 35 to the fuel injection valves 3.
[0080] A fuel injection amount control program 101 for calculating the amount of fuel to
be injected into each combustion chamber is stored in the ECU 35, and includes a required
fuel injection amount calculation program 102 for calculating the required fuel injection
amount eqgov and an actual fuel injection amount calculation program 103 for calculating
the actual injection fuel amount eqfin.
[0081] By executing the required fuel injection amount calculation program 102, the required
injection fuel amount eqgov is calculated based on the number of revolutions N of
the engine and the degree of opening D of the accelerator pedal, and by executing
the actual fuel injection amount calculation program 103, the actual fuel injection
amount eqfin is calculated each time fuel injection is carried out. Also, by executing
the fuel injection control program 101, fuel injections by the fuel injection valves
3 are controlled based on the required fuel injection amount eqgov and the actual
fuel injection amount eqfin calculated by the calculation programs 102, 103, respectively.
That is, the required fuel injection amount calculation program 102 constitutes a
required fuel injection amount calculation part according to the present invention,
and the actual fuel injection amount calculation program 103 constitutes an actual
fuel injection amount calculation part according to the present invention. In addition,
the fuel injection amount control program 101 constitutes a fuel injection amount
control part according to the present invention.
(MODIFICATION)
[0082] In the above-mentioned embodiment, reference has been made to the case where the
combustion state in each combustion chamber is switched by acceleration from the low
temperature combustion into the ordinary combustion, whereas it is switched by deceleration
from the ordinary combustion into the low temperature combustion. However, there may
be a case in which a part of the low load operating range is made to be a low temperature
operating range, and another part of the low load operating range, which is lower
in load than this low temperature operating range, is made to be an ordinary combustion
range. In this case, the combustion state can be occasionally switched by deceleration
from the low temperature combustion into the ordinary combustion, but at such a time,
too, the required fuel injection amount is made to be a switching determination parameter
used when the combustion state is switched from the low temperature combustion into
the ordinary combustion, similar to the above-mentioned case. As a result, the actual
fuel injection amount can be decreased more quickly at the time of deceleration in
which the combustion state is switched from the low temperature combustion into the
ordinary combustion. Accordingly, better deceleration performance can be obtained.
<SECOND EMBODIMENT>
[0083] Now, reference will be made to a combustion control apparatus for an internal combustion
engine according to a second embodiment of the present invention.
[0084] The construction of the internal combustion engine and its combustion control apparatus
according to this second embodiment is similar to the one shown in Fig. 1 as explained
in the above-mentioned first embodiment.
[0085] In the internal combustion engine 1 of this second embodiment, combustion is selectively
switched among the low temperature combustion, the ordinary combustion, and high EGR
combustion where the amount of the EGR gas supplied to each combustion chamber by
the exhaust gas recirculation device 40 is less than an amount of EGR gas when the
amount of soot generated becomes maximum and where the amount of EGR gas becomes substantially
maximum among EGR gas amounts in which the amount of soot generated is within an allowable
range.
[0086] In the high EGR combustion, the amount of the EGR gas supplied to each combustion
chamber is less than that at the time of low temperature combustion, but greater than
that at the time of ordinary combustion. As a result, in the high EGR combustion,
it is necessary to make the amount of the intake air supplied to each combustion chamber
smaller than that at the time of ordinary combustion. Accordingly, it is difficult
to perform the high EGR combustion in a stable manner in the high load operating range.
In order to cope with such a situation, in the internal combustion engine 1 in this
embodiment, the low temperature combustion range is set to be in the low load operating
range as in the above-mentioned first embodiment, but a high EGR combustion range,
which is an operating range of the engine where the high EGR combustion is performed,
is set to be in a medium load operating range, as shown in Fig. 5.
[0087] In addition, since in the high EGR combustion, the amount of the EGR gas supplied
to each combustion chamber is large and the amount of the intake air supplied thereto
is small, in comparison with those in the ordinary combustion, as stated above, the
air fuel ratio of the mixture in each combustion chamber is lower than that in the
ordinary combustion, as in the low temperature combustion, and hence combustion is
liable to become unstable. Thus, in the high EGR combustion, it is necessary to more
accurately control the air fuel ratio of the mixture in each combustion chamber so
as to obtain stable combustion.
[0088] In the internal combustion engine 1 of this second embodiment, when the required
load of the engine is changed as in the case of acceleration or deceleration of the
vehicle, the actual fuel injection amount is controlled to change gradually to reach
the required fuel injection amount so as to avoid generation of defects such as deterioration
of driveability due to a rapid change in the engine torque, combustion noise and misfiring,
etc., as in the case of the above-mentioned first embodiment.
[0089] Further, as stated above, in the high EGR combustion, combustion is liable to become
unstable as compared with that at the time of ordinary combustion, and there is a
fear that if the actual fuel injection amount is changed at the same speed or rate
as that at the time of ordinary combustion, the amount of smoke to be emitted from
the engine might be increased and/or misfiring might be induced. Therefore, the variable
fuel amount is set separately for the high EGR combustion and the ordinary combustion,
respectively, so that the change of the actual fuel injection amount becomes more
gradual at the time of high EGR combustion than at the time of ordinary combustion.
That is, similar to the low temperature combustion, a variable fuel amount in the
high EGR combustion is set to a value smaller than the variable fuel amount in the
ordinary combustion. Thus, the amount of injection fuel is controlled in a different
manner at the time of high EGR combustion and at the time of ordinary combustion,
based on the required fuel injection amount, the variable fuel amount, the number
of revolutions of the engine, etc.
[0090] In the combustion control apparatus for an internal combustion engine according to
this embodiment, a switching determination parameter used when the combustion state
is switched from the high EGR combustion into the ordinary combustion is made to be
the required fuel injection amount, as when switched from the low temperature combustion
into the ordinary combustion in the first embodiment, whereas a switching determination
parameter used when the combustion state is switched from the ordinary combustion
into the high EGR combustion is made to be the actual fuel injection amount, as when
switched from the ordinary combustion into the low temperature combustion in the first
embodiment. That is, a switching determination parameter used for switching the combustion
state at the time of acceleration is the actual fuel injection amount, whereas a switching
determination parameter used for switching the combustion state at the time of deceleration
is the actual fuel injection amount.
[0091] According to such combustion switching control, at the time of acceleration, the
combustion state is switched into the ordinary combustion more early so that the actual
fuel injection amount can be increased more quickly, thereby making it possible to
provide better acceleration performance. On the other hand, at the time of deceleration,
the combustion state is switched into the high EGR combustion after the actual fuel
injection amount has become a fuel injection amount corresponding to the high EGR
combustion range, namely, after the operating condition of the internal combustion
engine 1 has been changed into the high EGR combustion range, so that more stable
high EGR combustion can be carried out, thus making it possible to suppress the emission
of smoke, misfiring and deterioration of combustion noise.
[0092] Although in the above description, the internal combustion engine 1 is a multi-cylinder
internal combustion engine, the present invention is of course applied to a single-cylinder
internal combustion engine having a single cylinder, too.
[0093] According to a combustion control apparatus for an internal combustion engine constructed
in accordance with the present invention, the internal combustion engine, which selectively
switches between high air fuel ratio combustion and low air fuel ratio combustion,
can perform stable combustion and at the same time provide better acceleration or
deceleration performance.
[0094] While the invention has been described in terms of preferred embodiments, those skilled
in the art will recognize that the invention can be practiced with modifications within
the spirit and scope of the appended claims.
[0095] There is provided a combustion control apparatus which serves to enable the
[0096] There is provided a combustion control apparatus which serves to enable the engine
to perform stable combustion and provide better acceleration or deceleration performance.
Specifically, a switching determination parameter for switching from low air fuel
ratio combustion into high air fuel ratio combustion is made to be a required fuel
injection amount (eqgov), which is an amount of fuel injected into the combustion
chamber corresponding to an engine load required by a driver. A switching determination
parameter for switching from the high air fuel ratio combustion into the low air fuel
ratio combustion is made to be an actual fuel injection amount (eqfin), which is an
amount of fuel injected into the combustion chamber upon each fuel injection.
1. A combustion control apparatus for an internal combustion engine in which a combustion
state in a combustion chamber is selectively switched between high air fuel ratio
combustion in which combustion is performed at an air fuel ratio of a mixture in said
combustion chamber higher than a predetermined air fuel ratio, and low air fuel ratio
combustion in which combustion is performed at an air fuel ratio of the mixture in
said combustion chamber lower than or equal to said predetermined air fuel ratio,
characterized in that
a fuel injection control part (101) is provided which includes a required fuel injection
amount calculation part (102) that calculates a required fuel injection amount (eqgov)
which is an amount of injection fuel corresponding to a required load of said engine
(1) and an actual fuel injection amount calculation part (103) that calculates an
actual fuel injection amount (eqfin) which is an amount of fuel to be injected into
said combustion chamber each time fuel injection is performed, and said fuel injection
control part (101) gradually changes, upon change of said required load, said actual
fuel injection amount (eqfin) to said required fuel injection amount (eqgov), and
controls the change speed of said actual fuel injection amount (eqfin), which is gradually
changed when said combustion state is in said low air fuel ratio combustion, to be
more gradual than that when said combustion state is in said high air fuel ratio combustion,
wherein a switching determination parameter for switching said combustion state from
the low air fuel ratio combustion into said high air fuel ratio combustion is made
to be said required fuel injection amount (eqgov), and a switching determination parameter
for switching said combustion state from said high air fuel ratio combustion into
said low air fuel ratio combustion is made to be said actual fuel injection amount
(eqfin).
2. The combustion control apparatus for an internal combustion engine as set forth in
claim 1, characterized in that
the combustion state in said combustion chamber is switched into said high air fuel
ratio combustion when the operating condition of said internal combustion engine (1)
is in a high load operating range, and switched into said low air fuel ratio combustion
when the operating condition of said internal combustion engine (1) is in low load
operating range;
a switching determination parameter for switching said combustion state at the time
of a transient operation from said low load operating range into said high load operating
range is made to be said required fuel injection amount (eqgov); and
a switching determination parameter for switching said combustion state at the time
of a transient operation from said high load operating range into said low load operating
range is made to be said actual fuel injection amount (eqfin).
3. The combustion control apparatus for an internal combustion engine as set forth in
claim 1 or 2, characterized in that said required fuel injection amount calculation part (102) calculates said required
fuel injection amount (eqgov) based on the number of revolutions (N) of said engine
(1) and the degree of opening (D) of an accelerator pedal.
4. The combustion control apparatus for an internal combustion engine as set forth in
claim 1 or 2, characterized in that said fuel injection control part (101) sets a variable fuel amount (ΔQ), which is
a fuel injection amount able to be increased or decreased each time fuel injection
is carried out when said actual fuel injection amount (eqfin) is gradually changed,
separately for said low temperature combustion and said ordinary combustion, respectively,
and said fuel injection control part (101) further sets said variable fuel amount
(Δ Q) at the time of low air fuel ratio combustion to be smaller than said variable
fuel amount (Δ Q) at the time of high air fuel ratio combustion.
5. The combustion control apparatus for an internal combustion engine as set forth in
claim 2, characterized in that
said fuel injection control part (101) sets a variable fuel amount (Δ Q), which is
a fuel injection amount able to be increased or decreased each time fuel injection
is carried out when said actual fuel injection amount (eqfin) is gradually changed,
separately for said low temperature combustion and said ordinary combustion, respectively,
and said fuel injection control part (101) sets said variable fuel amount (Δ Q) at
the time of said low air fuel ratio combustion to be smaller than said variable fuel
amount (Δ Q) at the time of said high air fuel ratio combustion;
when said required load increases, said actual fuel injection amount calculation part
(103) compares an actual fuel injection amount (eqfin'), which was calculated upon
the last fuel injection and which is added by said variable fuel amount (Δ Q), with
the required fuel injection amount (eqgov), and calculates the value of the small
one as a current actual fuel injection amount (eqfin); and
when said required load decreases, said actual fuel injection amount calculation part
(103) compares the actual fuel injection amount (eqfin'), which was calculated upon
the last fuel injection and which is subtracted by said variable fuel amount (ΔQ),
with the required fuel injection amount (eqgov), and calculates the value of the greater
one as a current actual fuel injection amount (eqfin).
6. The combustion control apparatus for an internal combustion engine as set forth in
claim 5, characterized in that a comparison is made between said current actual fuel injection amount (eqfin) and
said required fuel injection amount (eqgov), and the value of the greater one is made
to be a switching determination parameter for switching said combustion state.
7. The combustion control apparatus for an internal combustion engine as set forth in
claim 1 or 2, characterized in that said internal combustion engine (1) selectively switches between low temperature
combustion in which generation of soot is suppressed by increasing the amount of burnt
gas components in said combustion chamber more than the amount of burnt gas components
therein at the time when the amount of soot generated becomes maximum due to the burnt
gas components in said combustion chamber being increased, and ordinary combustion
in which the amount of unburnt gas components in said combustion chamber is less than
the amount of burnt gas components at the time when the amount of soot generated becomes
maximum, and makes said low air fuel ratio combustion as said low temperature combustion,
and said high air fuel ratio combustion as said ordinary combustion.
8. The combustion control apparatus for an internal combustion engine as set forth in
claim 7, characterized in that said predetermined air fuel ratio is an upper limit of an air fuel ratio at the time
of low temperature combustion.
9. The combustion control apparatus for an internal combustion engine as set forth in
claim 7, characterized in that
an operating range of said internal combustion engine (1) in which said combustion
state is made to be said low temperature combustion is made as a low temperature combustion
range, and an operating range of said internal combustion engine (1) in which said
combustion state is made to be said ordinary combustion is made as an ordinary combustion
range; and
by using said required fuel injection amount (eqgov) as a switching determination
parameter for switching said combustion state from said low temperature combustion
into said ordinary combustion, said combustion state is switched from said low temperature
combustion into said ordinary combustion when said required fuel injection amount
(eqgov) becomes an fuel injection amount corresponding to a threshold between said
low temperature combustion range and said ordinary combustion range.
10. The combustion control apparatus for an internal combustion engine as set forth in
claim 7, characterized in that
an operating range of said internal combustion engine (1) in which said combustion
state is made to be said low temperature combustion is made as a low temperature combustion
range, and an operating range of said internal combustion engine (1) in which said
combustion state is made to be said ordinary combustion is made as an ordinary combustion
range; and
by using said actual fuel injection amount (eqfin) as a switching determination parameter
for switching said combustion state from said ordinary combustion into said low temperature
combustion, said combustion state is switched from said ordinary combustion into said
low temperature combustion when said actual fuel injection amount (eqfin) becomes
a fuel injection amount corresponding to a threshold between said low temperature
combustion range and said ordinary combustion range.
11. The combustion control apparatus for an internal combustion engine as set forth in
claim 1 or 2, further characterized by an exhaust gas purification catalyst (20) disposed in an exhaust passage (19) of
said internal combustion engine (1) and having a property of gradually accumulating
sulfur components in an exhaust gas discharged from said engine (1),
wherein said low air fuel ratio combustion is combustion that is performed at the
time of sulfur poisoning regeneration control to decrease the air fuel ratio of said
exhaust gas due to combustion at a lowered air fuel ratio of the mixture in said combustion
chamber so as to raise the temperature of said exhaust gas purification catalyst (20)
and make an ambient atmosphere a rich one for the release of the accumulated sulfur
components.
12. The combustion control apparatus for an internal combustion engine as set forth in
claim 7, further characterized by an exhaust gas purification catalyst (20) disposed in an exhaust passage (19) of
said internal combustion engine (1) and having a property of gradually accumulating
sulfur components in an exhaust gas discharged from said engine (1),
wherein said low temperature combustion is combustion that is performed at the time
of sulfur poisoning regeneration control to decrease the air fuel ratio of said exhaust
gas due to combustion at a lowered air fuel ratio of the mixture in said combustion
chamber so as to raise the temperature of said exhaust gas purification catalyst (20)
and make an ambient atmosphere a rich one for the release of the accumulated sulfur
components.
1. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine, in der ein
Verbrennungszustand in einer Brennkammer wahlweise zwischen einer Verbrennung bei
einem hohen Luftkraftstoffverhältnis, bei der eine Verbrennung bei einem höheren Luftkraftstoffverhältnis
eines Gemisches in der Brennkammer als ein vorherbestimmtes Luftkraftstoffverhältnis
durchgeführt wird, und einer Verbrennung bei einem niedrigen Luftkraftstoffverhältnis
geschaltet wird, bei der eine Verbrennung bei einem Luftkraftstoffverhältnis des Gemisches
in der Brennkammer durchgeführt wird, das niedriger oder gleich einem vorherbestimmten
Luftkraftstoffverhältnis ist, dadurch gekennzeichnet, dass
ein Kraftstoffeinspritzsteuerungsteil (101) vorgesehen ist, das ein Soll-Kraftstoffeinspritzmengenberechnungsteil
(102), der eine Soll-Kraftstoffeinspritzmenge (eqgov) berechnet, die eine Menge eines
Einspritzkraftstoffs ist, die einer Soll-Last der Maschine (1) entspricht, und einen
Ist-Kraftstoffeinspritzmengenberechnungsteil (103) hat, der eine Ist-Kraftstoffeinspritzmenge
(eqfin) berechnet, die eine Kraftstoffmenge ist, die jedes Mal, wenn keine Kraftstoffeinspritzung
durchgeführt wird, in die Brennkammer eingespritzt werden soll, und wobei der Kraftstoffeinspritzsteuerungsteil
(101) auf eine Änderung der Soll-Last stufenartig die Ist-Kraftstoffeinspritzmenge
(eqfin) zu der Soll-Kraftstoffeinspritzmenge (eqgov) ändert und die Änderungsgeschwindigkeit
der Ist-Kraftstoffeinspritzmenge (eqfin) steuert, die, wenn der Verbrennungszustand
eine Verbrennung bei einem niedrigen Luftkraftstoffverhältnis ist, stufenartig geändert
wird, um noch stufenartiger zu sein, als wenn der Verbrennungszustand eine Verbrennung
bei dem hohen Luftkraftstoffverhältnis ist,
wobei ein Schaltbestimmungsparameter zum Schalten des Verbrennungszustands von der
Verbrennung bei einem niedrigen Luftkraftstoffverhältnis in die Verbrennung bei einem
hohen Luftkraftstoffverhältnis zu der Sollkraftstoffeinspritzmenge (eqgov) gemacht
wird und ein Schaltbestimmungsparameter zum Schalten des Verbrennungszustands von
der Verbrennung bei einem hohen Luftkraftstoffverhältnis in die Verbrennung bei einem
niedrigen Luftkraftstoffverhältnis zu der Ist-Kraftstoffeinspritzmenge (eqfin) gemacht
wird.
2. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
1, dadurch gekennzeichnet, dass
der Verbrennungszustand in der Brennkammer in die Verbrennung bei einem hohen Luftkraftstoffverhältnis
geschaltet wird, wenn die Betriebsbedingung der Brennkraftmaschine (1) in einem Hochlastbetriebsbereich
ist, und in die Verbrennung bei einem niedrigen Luftkraftstoffverhältnis geschaltet
wird, wenn die Betriebsbedingung der Brennkraftmaschine (1) in einem Niederlastbetriebsbereich
ist;
ein Schaltbestimmungsparameter zum Schalten des Verbrennungszustands zu der Zeit eines
Übergangsbetriebs von dem Niederlassbetriebsbereich in den Hochlastbetriebsbereich
zu der Soll-Kraftstoffeinspritzmenge (eqgov) gemacht wird; und
ein Schaltbestimmungsparameter zum Schalten des Verbrennungszustands zu der Zeit eines
Übergangsbetriebs von dem Hochlastbetriebsbereich in den Niederlassbetriebsbereich
zu der Soll-Kraftstoffeinspritzmenge (eqfin) gemacht wird.
3. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
1 oder 2, dadurch gekennzeichnet, dass der Soll-Kraftstoffeinspritzmengenberechnungsteil (102) die Soll-Kraftstoffeinspritzmenge
(eqgov) auf der Grundlage der Anzahl von Umdrehungen (N) der Maschine (1) und dem
Öffnungsgrad (D) eines Gaspedals berechnet.
4. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
1 oder 2, dadurch gekennzeichnet, dass der Kraftstoffeinspritzsteuerungsteil (101) eine variable Kraftstoffmenge (ΔQ) festsetzt,
die eine Kraftstoffeinspritzmenge ist, die jedes Mal, wenn eine Kraftstoffeinspritzung
durchgeführt wird, wenn die Ist-Kraftstoffeinspritzmenge (eqfin) stufenartig geändert
wird, getrennt jeweils für die Niedertemperaturverbrennung und die gewöhnliche Verbrennung
vergrößert oder verringert werden kann, und der Kraftstoffeinspritzsteuerungsteil
(101) die variable Kraftstoffmenge (ΔQ) zu der Zeit einer Verbrennung bei einem niedrigen
Luftkraftstoffverhältnis festsetzt, um kleiner zu sein als die variable Kraftstoffmenge
(ΔQ) zu der Zeit einer Verbrennung bei einem hohen Luftkraftstoffverhältnis.
5. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
2, dadurch gekennzeichnet, dass
der Kraftstoffeinspritzsteuerungsteil (101) eine variable Kraftstoffmenge (ΔQ) festsetzt,
die eine Kraftstoffeinspritzmenge ist, die jedes Mal, wenn eine Kraftstoffeinspritzung
durchgeführt wird, wenn die Ist-Kraftstoffeinspritzmenge (eqfin) stufenartig geändert
wird, getrennt jeweils für die Niedertemperaturverbrennung und die gewöhnliche Verbrennung
vergrößert oder verringert werden kann, und der Kraftstoffeinspritzsteuerungsteil
(101) die variable Kraftstoffmenge (ΔQ) zu der Zeit der Verbrennung bei einem niedrigen
Luftkraftstoffverhältnis festsetzt, um kleiner zu sein als die variable Kraftstoffmenge
(ΔQ) zu der Zeit der Verbrennung bei einem hohen Luftkraftstoffverhältnis;
wenn sich die Soll-Last vergrößert, der Ist-Kraftstoffeinspritzmengenberechnungsteil
(103) eine Ist-Kraftstoffeinspritzmenge (eqfin'), die auf die letzte Kraftstoffeinspritzung
berechnet wurde und die zu der variablen Kraftstoffmenge (ΔQ) addiert wurde, mit der
Soll-Kraftstoffeinspritzmenge (eqgov) vergleicht und den Wert der Kleinen als eine
gegenwärtige Ist-Kraftstoffeinspritzmenge (eqfin) berechnet; und
wenn sich die Soll-Last verringert, der Ist-Kraftstoffeinspritzmengenberechnungsteil
(103) die Ist-Kraftstoffeinspritzmenge (eqfin'), die auf die letzte Kraftstoffeinspritzung
berechnet wurde und die von der variablen Kraftstoffmenge (ΔQ) abgezogen wurde, mit
der Soll-Kraftstoffeinspritzmenge (eqgov) vergleicht und den Wert der Größeren als
eine gegenwärtige Ist-Kraftstoffeinspritzmenge (eqfin) berechnet.
6. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
5, dadurch gekennzeichnet, dass ein Vergleich zwischen der gegenwärtigen Ist-Kraftstoffeinspritzmenge (eqfin) und
der Soll-Kraftstoffeinspritzmenge (eqgov) gemacht wird und der Wert der Größeren zu
einem Schaltbestimmungsparameter zum Schalten des Verbrennungszustands gemacht wird.
7. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
1 oder 2, dadurch gekennzeichnet, dass die Brennkraftmaschine (1) wahlweise zwischen einer Niedertemperaturverbrennung,
in der die Erzeugung von Ruß dadurch unterdrückt wird, dass die Menge an verbrannten
Gaskomponenten in der Brennkammer weiter über die Menge an verbrannten Gaskomponenten
darin zu der Zeit, zu der die Menge an erzeugtem Ruß aufgrund der Erhöhung der verbrannten
Gaskomponenten in der Brennkammer maximal wird, erhöht wird, und einer gewöhnlichen
Verbrennung schaltet, in der die Menge an nicht verbrannten Gaskomponenten in der
Brennkammer geringer ist als die Menge der verbrannten Gaskomponenten zu der Zeit,
zu der die Menge an erzeugtem Ruß maximal wird, und die Verbrennung bei einem niedrigen
Luftkraftstoffverhältnis zu der Niedertemperaturverbrennung und die Verbrennung bei
einem hohen Luftkraftstoffverhältnis zu der gewöhnlichen Verbrennung macht.
8. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
7, dadurch gekennzeichnet, dass das vorherbestimmte Luftkraftstoffverhältnis eine obere Grenze eines Luftkraftstoffverhältnisses
zu der Zeit einer Niedertemperaturverbrennung ist.
9. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
7, dadurch gekennzeichnet, dass
ein Betriebsbereich der Brennkraftmaschine (1), in dem der Verbrennungszustand zu
der Niedertemperaturverbrennung gemacht wird, zu einem Niedertemperaturverbrennungsbereich
gemacht wird, und ein Betriebsbereich der Brennkraftmaschine (1), in dem der Verbrennungszustand
zu der gewöhnlichen Verbrennung gemacht wird, zu einem gewöhnlichen Verbrennungsbereich
gemacht wird; und
durch die Verwendung der Soll-Kraftstoffeinspritzmenge (eqgov) als einen Schaltbestimmungsparameter
zum Schalten des Verbrennungszustands von der Niedertemperaturverbrennung in die gewöhnliche
Verbrennung, der Verbrennungszustand von der Niedertemperaturverbrennung in die gewöhnliche
Verbrennung geschaltet wird, wenn die Soll-Kraftstoffeinspritzmenge (eqgov) eine Kraftstoffeinspritzmenge
wird, die einem Grenzwert zwischen dem Niedertemperaturverbrennungsbereich und dem
gewöhnlichen Verbrennungsbereich entspricht.
10. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
7, dadurch gekennzeichnet, dass
ein Betriebsbereich der Brennkraftmaschine (1), in dem der Verbrennungszustand zu
der Niedertemperaturverbrennung gemacht wird, zu einem Niedertemperaturverbrennungsbereich
gemacht wird, und ein Betriebsbereich der Brennkraftmaschine (1), in dem der Verbrennungszustand
zu der gewöhnlichen Verbrennung gemacht wird, zu einem gewöhnlichen Verbrennungsbereich
gemacht wird; und
durch die Verwendung der Ist-Kraftstoffeinspritzmenge (eqfin) als einen Schaltbestimmungsparameter
zum Schalten des Verbrennungszustands von der gewöhnlichen Verbrennung in die Niedertemperaturverbrennung,
der Verbrennungszustand von der gewöhnlichen Verbrennung in die Niedertemperaturverbrennung
geschaltet wird, wenn die Ist-Kraftstoffeinspritzmenge (eqfin) eine Kraftstoffeinspritzmenge
wird, die einem Grenzwert zwischen dem Niedertemperaturverbrennungsbereich und dem
gewöhnlichen Verbrennungsbereich entspricht.
11. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
1 oder 2, ferner gekennzeichnet durch einen Abgasreinigungskatalysator (20), der in einem Abgaskanal (19) der Brennkraftmaschine
(1) eingerichtet ist und eine Eigenschaft eines stufenartigen Ansammelns von Schwefelkomponenten
im von der Maschine (1) abgelassenen Abgas hat,
wobei die Verbrennung bei einem niedrigen Luftkraftstoffverhältnis eine Verbrennung
ist, die zu der Zeit einer Schwefelvergiftungsregenerationssteuerung durchgeführt
wird, um das Luftkraftstoffverhältnis des Abgases aufgrund einer Verbrennung bei einem
abgesenkten Luftkraftstoffverhältnis des Gemisches in der Brennkammer abzusenken,
um so die Temperatur des Abgasreinigungskatalysators (20) zu erhöhen und eine Umgebungsatmosphäre
für das Ausschütten der angesammelten Schwefelkomponenten anzureichern.
12. Vorrichtung zur Steuerung der Verbrennung in einer Brennkraftmaschine nach Anspruch
7, ferner gekennzeichnet durch einen Abgasreinigungskatalysator (20), der in einem Abgaskanal (19) der Brennkraftmaschine
(1) eingerichtet ist und eine Eigenschaft eines stufenartigen Ansammelns von Schwefelkomponenten
in einem von der Maschine (1) abgelassenen Abgas hat,
wobei die Niedertemperaturverbrennung eine Verbrennung ist, die zu einer Zeit einer
Schwefelvergiftungsregenerationssteuerung durchgeführt wird, um das Luftkraftstoffverhältnis
des Abgases aufgrund einer Verbrennung bei einem verringerten Luftkraftstoffverhältnis
des Gemisches in der Brennkammer zu verringern, um so die Temperatur des Abgasreinigungskatalysators
(20) zu erhöhen und eine Umgebungsatmosphäre für das Ausschütten der angesammelten
Schwefelkomponenten anzureichern.
1. Appareil de commande de combustion pour un moteur à combustion interne dans lequel
un état de combustion dans une chambre de combustion est commuté de manière sélective
entre une combustion à rapport air-carburant élevé dans laquelle la combustion est
réalisée à un rapport air-carburant d'un mélange dans ladite chambre de combustion
plus élevé qu'un rapport air-carburant prédéterminé, et combustion à rapport air-carburant
bas dans laquelle la combustion est réalisée à un rapport air-carburant du mélange
dans ladite chambre de combustion inférieur ou égal audit rapport air-carburant prédéterminé,
caractérisé en ce que
une partie de commande d'injection de carburant (101) est prévue, qui comprend une
partie de calcul de quantité d'injection de carburant exigée (102) qui calcule une
quantité d'injection de carburant exigée (eqgov) qui est une quantité de carburant
d'injection correspondant à une charge exigée dudit moteur (1) et une partie de calcul
de quantité d'injection de carburant réelle (103) qui calcule une quantité d'injection
de carburant réelle (eqfin) qui est une quantité de carburant devant être injectée
dans ladite chambre de combustion chaque fois qu'une injection de carburant est réalisée,
et ladite partie de commande d'injection de carburant (101) change progressivement,
lors d'un changement de ladite charge exigée, ladite quantité d'injection de carburant
réelle (eqfin) vers ladite quantité d'injection de carburant exigée (eqgov), et commande
la vitesse de changement de ladite quantité d'injection de carburant réelle (eqfin),
qui est progressivement changée quand ledit état de combustion est dans ladite combustion
à rapport air-carburant bas, afin d'être plus progressive que quand ledit état de
combustion est dans ladite combustion à rapport air-carburant élevé,
un paramètre de détermination de commutation afin de commuter ledit état de combustion
de la combustion à rapport air-carburant bas à ladite combustion à rapport air-carburant
élevé étant amené à être ladite quantité d'injection de carburant exigée (eqgov),
et un paramètre de détermination de commutation afin de commuter ledit état de combustion
de ladite combustion à rapport air-carburant élevé à ladite combustion à rapport air-carburant
bas étant amené à être ladite quantité d'injection de carburant réelle (eqfin) .
2. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
1, caractérisé en ce que
l'état de combustion dans ladite chambre de combustion est commuté dans ladite combustion
à rapport air-carburant élevé quand la condition de fonctionnement dudit moteur à
combustion interne (1) est dans une plage de fonctionnement à charge élevée, et commuté
dans ladite combustion à rapport air-carburant bas quand la condition de fonctionnement
dudit moteur à combustion interne (1) est dans la plage de fonctionnement à faible
charge ;
un paramètre de détermination de commutation afin de commuter ledit état de combustion
au moment d'un fonctionnement transitoire de ladite plage de fonctionnement à faible
charge à ladite plage de fonctionnement à charge élevée est amené à être ladite quantité
d'injection de carburant exigée (eqgov) ; et
un paramètre de détermination de commutation afin de commuter ledit état de combustion
au moment d'un fonctionnement transitoire de ladite plage de fonctionnement à charge
élevée à ladite plage de fonctionnement à faible charge est amené à être ladite quantité
d'injection de carburant réelle (eqfin).
3. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
1 ou 2, caractérisé en ce que ladite partie de calcul de quantité d'injection de carburant exigée (102) calcule
ladite quantité d'injection de carburant exigée (eqgov) sur la base du nombre de tours
(N) dudit moteur (1) et du degré d'ouverture (D) d'une pédale d'accélérateur.
4. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
1 ou 2, caractérisé en ce que ladite partie de commande d'injection de carburant (101) établit une quantité de
carburant variable (ΔQ), qui est une quantité d'injection de carburant qui peut être
augmentée ou diminuée chaque fois qu'une injection de carburant est réalisée quand
ladite quantité d'injection de carburant réelle (eqfin) est progressivement changée,
séparément pour ladite combustion à basse température et ladite combustion ordinaire,
respectivement, et ladite partie de commande d'injection de carburant (101) établit
en outre ladite quantité de carburant variable (ΔQ) au moment d'une combustion à rapport
air-carburant bas afin d'être plus petite que ladite quantité de carburant variable
(ΔQ) au moment de la combustion à rapport air-carburant élevé.
5. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
2, caractérisé en ce que
ladite partie de commande d'injection de carburant (101) établit une quantité de carburant
variable (ΔQ), qui est une quantité d'injection de carburant qui peut être augmentée
ou diminuée chaque fois qu'une injection de carburant est réalisée quand ladite quantité
d'injection de carburant réelle (eqfin) est progressivement changée, séparément pour
ladite combustion à basse température et ladite combustion ordinaire, respectivement,
et ladite partie de commande d'injection de carburant (101) établit ladite quantité
de carburant variable (ΔQ) au moment de ladite combustion à rapport air-carburant
bas afin d'être plus petite que ladite quantité de carburant variable (ΔQ) au moment
de ladite combustion à rapport air-carburant élevé ;
quand ladite charge exigée augmente, ladite partie de calcul de quantité d'injection
de carburant réelle (103) compare une quantité d'injection de carburant réelle (eqfin'),
qui a été calculée lors de la dernière injection de carburant et qui est ajoutée par
ladite quantité de carburant variable (ΔQ), et la quantité d'injection de carburant
exigée (eqgov), et calcule la valeur de la petite comme une quantité d'injection de
carburant réelle courante (eqfin) ; et
quand ladite charge exigée diminue, ladite partie de calcul de quantité d'injection
de carburant réelle (103) compare la quantité d'injection de carburant réelle (eqfin'),
qui a été calculée lors de la dernière injection de carburant et qui est soustraite
par ladite quantité de carburant variable (ΔQ), et la quantité d'injection de carburant
exigée (eqgov), et calcule la valeur de la plus grande comme une quantité d'injection
de carburant réelle courante (eqfin).
6. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
5, caractérisé en ce qu'une comparaison est faite entre ladite quantité d'injection de carburant réelle courante
(eqfin) et ladite quantité d'injection de carburant exigée (eqgov), et la valeur de
la plus grande est amenée à être un paramètre de détermination de commutation afin
de commuter ledit état de combustion.
7. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
1 ou 2, caractérisé en ce que ledit moteur à combustion interne (1) commute de manière sélective entre une combustion
à basse température dans laquelle une génération de suie est supprimée en augmentant
la quantité de composants de gaz brûlés dans ladite chambre de combustion davantage
que la quantité de composants de gaz brûlés au moment où la quantité de suie générée
devient maximum du fait des composants de gaz brûlés dans ladite chambre de combustion
qui ont augmenté, et une combustion ordinaire dans laquelle la quantité de composants
de gaz non brûlés dans ladite chambre de combustion est plus faible que la quantité
de composants de gaz brûlés au moment où la quantité de suie générée devient maximum,
et fait de ladite combustion à rapport air-carburant bas ladite combustion à basse
température, et ladite combustion à rapport air-carburant élevé ladite combustion
ordinaire.
8. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
7, caractérisé en ce que ledit rapport air-carburant prédéterminé est une limite supérieure d'un rapport air-carburant
au moment de la combustion à basse température.
9. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
7, caractérisé en ce que
une plage de fonctionnement dudit moteur à combustion interne (1) dans laquelle ledit
état de combustion est amené à être ladite combustion à basse température est amenée
à être une plage de combustion à basse température, et une plage de fonctionnement
dudit moteur à combustion interne (1) dans laquelle ledit état de combustion est amené
à être ladite combustion ordinaire est amenée à être une plage de combustion ordinaire
; et
en utilisant ladite quantité d'injection de carburant exigée (eqgov) comme paramètre
de détermination de commutation afin de commuter ledit état de combustion de ladite
combustion à basse température à ladite combustion ordinaire, ledit état de combustion
est commuté de ladite combustion à basse température à ladite combustion ordinaire
quand ladite quantité d'injection de carburant exigée (eqgov) devient une quantité
d'injection de carburant correspondant à un seuil entre ladite plage de combustion
à basse température et ladite plage de combustion ordinaire.
10. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
7, caractérisé en ce que
une plage de fonctionnement dudit moteur à combustion interne (1) dans laquelle ledit
état de combustion est amené à être ladite combustion à basse température est amenée
à être une plage de combustion à basse température, et une plage de fonctionnement
dudit moteur à combustion interne (1) dans laquelle ledit état de combustion est amené
à être ladite combustion ordinaire est amenée à être une plage de combustion ordinaire
; et
en utilisant ladite quantité d'injection de carburant réelle (eqfin) comme paramètre
de détermination de commutation afin de commuter ledit état de combustion de ladite
combustion ordinaire à ladite combustion à basse température, ledit état de combustion
est commuté de ladite combustion ordinaire à ladite combustion à basse température
quand ladite quantité d'injection de carburant réelle (eqfin) devient une quantité
d'injection de carburant correspondant à un seuil entre ladite plage de combustion
à basse température et ladite plage de combustion ordinaire.
11. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
1 ou 2, caractérisé en outre par un catalyseur de purification de gaz d'échappement (20) disposé dans un passage d'échappement
(19) dudit moteur à combustion interne (1) et ayant une propriété d'accumulation progressive
de composants soufrés dans un gaz d'échappement libéré par ledit moteur (1),
ladite combustion à rapport air-carburant bas étant une combustion qui est réalisée
au moment de la commande de régénération d'empoisonnement par le soufre afin de diminuer
le rapport air-carburant dudit gaz d'échappement du fait d'une combustion à un rapport
air-carburant abaissé du mélange dans ladite chambre de combustion de façon à élever
la température dudit catalyseur de purification de gaz d'échappement (20) et à faire
d'une atmosphère ambiante une riche pour la libération des composants soufrés accumulés.
12. Appareil de commande de combustion pour un moteur à combustion interne selon la revendication
7, caractérisé en outre par un catalyseur de purification de gaz d'échappement (20) disposé dans un passage d'échappement
(19) dudit moteur à combustion interne (1) et ayant une propriété d'accumulation progressive
de composants soufrés dans un gaz d'échappement libéré par ledit moteur (1),
ladite combustion à basse température étant une combustion qui est réalisée au moment
de la commande de régénération d'empoisonnement par le soufre afin de diminuer le
rapport air-carburant dudit gaz d'échappement du fait d'une combustion à un rapport
air-carburant abaissé du mélange dans ladite chambre de combustion de façon à élever
la température dudit catalyseur de purification de gaz d'échappement (20) et à faire
d'une atmosphère ambiante une riche pour la libération des composants soufrés accumulés.