TECHNICAL FIELD
[0001] [0002] The present invention relates to an engine control system for a vehicle which
is configured to control an engine, using a plurality of control modes.
DESCRIPTION OF THE RELATED ART
[0002] [0003] An exemplary engine control system built into a vehicle such as a motorcycle
is configured to set one control mode selected from among a plurality of control modes
such as a high driving power mode for providing a high acceleration capability, an
economy mode for achieving a high fuel efficiency, and a normal mode, and control
the engine using the set control mode. Japanese Laid-Open
[0003] Patent Application Publication No.
2005-023991 discloses an engine control system configured to freely switch a control mode by
a driver's operation of a mode select switch coupled to the input of the engine control
system.
[0004] [0004] An engine control system is configured to obtain command values such as an
ignition timing and a fuel injection amount according to input values indicating driving
states such as accelerator opening degree and an engine speed, and control the engine
according to the command values. The command values derived from the input values
are varied depending on the control mode. A conventional engine control system is
configured to switch a control mode in response to the operation of the mode select
switch regardless of the driving state. This will increase a chance that a driving
state fluctuation increases, for example, the operation and output of the engine fluctuate,
because of the switching of the control mode, depending on the driving state, which
makes driving feel worse.
SUMMARY OF THE INVENTION
[0005] [0005] The present invention has been developed in view of the circumstances, and
an object of the present invention is to improve diving feel of a driver driving a
vehicle including an engine control system configured to control an engine using a
plurality of control modes.
[0006] [0006] According to a first aspect of the present invention, an engine control system
for a vehicle, which is configured to control an engine using a plurality of control
modes, comprising: a controller configured to selectively set a first control mode
or a second control mode and to control the engine using the set control mode, the
engine being operable with a smaller fuel amount in the second control mode than in
the first control mode; and a mode switching device for switching the control mode
set in the controller between the first control mode and the second control mode;
is
characterized in that the controller is configured to determine that a command for switching the control
mode is valid if a predetermined driving condition is met, in response to the command
input to the mode switching device, and to determine that the command is invalid if
the predetermined driving condition is not met, in response to the command input to
the mode switching device.
[0007] [0007] In accordance with the above configuration, the control mode is not switched
when the predetermined driving condition is not met, and therefore, a driving state
fluctuation due to the switching of the control mode is suppressed. This makes it
possible to maintain good driving feel.
[0008] [0008] The engine control system for the vehicle may further comprise an acceleration
determiner configured to determine whether or not the vehicle is driving with a predetermined
acceleration; and the predetermined driving condition may include a condition that
the vehicle is driving with an acceleration less than the predetermined acceleration.
[0009] [0009] In accordance with the configuration, in a case where the vehicle is accelerated,
the switching of the control mode is inhibited to prevent fluctuation of the operation
and output of the engine and fluctuation the vehicle speed, which would occur if the
control mode is switched. As a result, the driving state fluctuation due to the switching
of the control mode can be suppressed.
[0010] [0010] The engine control system for the vehicle may further comprise a driving power
transmission determiner configured to determine whether or not a transmission path
of a driving power generated in the engine is disconnected; and the predetermined
driving condition may include a condition that the transmission path is disconnected.
[0011] [0011] In accordance with such a configuration, even when the operation and output
of the engine change due to the switching of the control mode, in the state where
the driving power transmission path is disconnected, this change is less likely to
bring about the driving state fluctuation. Therefore, in this case, the switching
of the control mode is permitted and as a result, the control mode can be switched
without worsening driving feel.
[0012] [0012] The engine control system for the vehicle may further comprise a gear position
sensor for detecting a gear position of a transmission mounted in the vehicle; and
the predetermined driving condition may include a condition that the gear position
detected by the gear position sensor may be a gear position corresponding to a reduction
gear ratio less than a predetermined reduction gear ratio which is not more than a
maximum reduction gear ratio.
[0013] [0013] In accordance with such a configuration, the switching of the control mode
is inhibited when the reduction gear ratio is not a reduction gear ratio which is
less than a predetermined reduction gear ratio which is not more than the maximum
reduction gear ratio, i.e., a transmission gear which is lower than a certain transmission
gear is set in the transmission. The lower transmission gear is set in a driving state
where a vehicle speed tends to change significantly in a state where acceleration
is required, during, for example, starting of the vehicle, or a state where a relatively
large engine braking force is applied to decelerate the vehicle. In this case, the
switching of the control mode is inhibited, and as a result, the driving state fluctuation
due to the switching of the control mode can be suppressed.
[0014] [0014] The engine control system for the vehicle may further comprise a vehicle speed
sensor for detecting a vehicle speed; and the predetermined driving condition may
include a condition that the vehicle speed detected by the vehicle speed sensor falls
within a predetermined speed range which is not less than a predetermined first speed
and not more than a predetermined second speed. The predetermined first speed may
be higher than zero and the second predetermined speed may be set to a value larger
than a value of the predetermined first speed.
[0015] [0015] In accordance with such a configuration, the switching of the control mode
is inhibited in a case where the vehicle speed is in a low speed range which is less
than the first speed and acceleration is required to start the motorcycle. Therefore,
the speed fluctuation or the driving state fluctuation due to the switching of the
control mode can be suppressed. In addition, the switching of the control mode is
inhibited in a case where the vehicle speed is in a high speed range which is more
than the second speed and there is not a substantial difference in the operation command
values for the engine, such as a fuel injection amount, or the like, regardless of
the control mode. As a result, an unnecessary switching operation of the control mode
can be prevented.
[0016] [0016] The mode switching device may include an operation member which is operated
by a driver; and the controller may be configured to determine that the command for
switching the control mode has been input only when an operation time for which the
operation member is operated by the driver falls within a predetermined time range
which is not less than a predetermined first time and not more than a predetermined
second time.
[0017] [0017] This makes it possible to prevent the control mode from being switched inadvertently
by the fact that something touches the mode select switch by mistake or continues
to contact the mode select switch for a long time.
[0018] [0018] The engine control system for the vehicle may further comprise a gear position
sensor for detecting a gear position of a transmission mounted in the vehicle; an
engine speed sensor for detecting an engine speed of the engine; and a throttle valve
opening degree sensor for detecting an opening degree of a throttle valve for controlling
an amount of air fed to the engine. The predetermined driving condition may include
a condition that the gear position detected by the gear position sensor is a gear
position corresponding to a reduction gear ratio which is less than a predetermined
reduction gear ratio which is not more than a maximum reduction gear ratio, a condition
that the engine speed detected by the engine speed sensor is not more than a predetermined
engine speed, and a condition that the opening degree detected by the throttle valve
opening degree sensor is not more than a predetermined opening degree.
[0019] [0019] In accordance with the configuration, in a case where the vehicle is accelerated,
the switching of the control mode is inhibited to prevent fluctuation of the operation
and output of the engine and fluctuation of the vehicle speed, which would occur if
the control mode is switched. As a result, the driving state fluctuation due to the
switching of the control mode can be suppressed. Detecting whether or not the vehicle
is being accelerated is implemented without using a sensor exclusively for detection
of acceleration of the vehicle. As a result, the number of components and a manufacturing
cost can be reduced.
[0020] [0020] The engine control system for the vehicle may further comprise a sensor for
outputting a detection value used to determine whether or not a predetermined driving
condition is met; and an abnormality determiner configured to determine whether or
not abnormality occurs in the sensor. The controller may be configured to restrict
switching of the control mode when the abnormality determiner determines that the
abnormality occurs in the sensor.
[0021] [0021] In accordance with such a configuration, the switching of the control mode
is restricted in a case where abnormality occurs in the sensor and it is difficult
to correctly determine whether or not the driving condition is met. This reduces a
chance of misdetermination that the driving condition is met, and hence an incorrect
switching of the control mode.
[0022] [0022] According to another aspect of the present invention, an engine control system
for a vehicle, which is configured to control an engine using a plurality of control
modes, comprising a controller configured to selectively set a first control mode
or a second control mode and to control the engine using the set control mode, the
first control mode and the second control mode being different from each other in
control for driving; a mode switching device for switching the control mode set in
the controller between the first control mode and the second control mode; is
characterized in that the controller is configured to determine that a command for switching the control
mode is valid if a predetermined driving condition is met, in response to the command
input to the mode switching device, and to determine that the command is invalid if
the predetermined driving condition is not met, in response to the command input to
the mode switching device. In accordance with the above configuration, also, the control
mode is not switched when the predetermined driving condition is not met, and therefore,
a driving state fluctuation due to the switching of the control mode is suppressed.
This makes it possible to maintain good driving feel.
[0023] [0023] The engine control system for the vehicle may further comprise a driving power
transmission determiner configured to determine whether or not a transmission path
of a driving power generated in the engine is disconnected. The predetermined driving
condition may include a condition that the transmission path is disconnected.
[0024] [0024] The engine control system for the vehicle may further comprise a display device.
The controller may be configured to cause the display device to conduct display in
a different manner according to the set control mode.
[0025] [0025] The controller may be configured to set the first control mode at re-start
of the engine if the command is not input to the mode switching device before the
engine re-starts, and to set the second control mode at re-start of the engine when
a command for switching the control mode to the second control mode is input to the
mode switching device before the engine re-starts, when the engine is stopped in a
state where the second control mode is set.
[0026] [0026] The above and further objects and features of the invention will more be apparent
from the following detailed description with accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] [0027] Fig. 1 is a left side view of a motorcycle including an engine control system
for a vehicle according to an embodiment of the present invention.
[0028] [0028] Fig. 2 is a schematic view showing a configuration of an engine and constituents
in the vicinity of the engine of Fig. 1 and a configuration of an entire engine control
system built into motorcycle of Fig. 1.
[0029] [0029] Fig. 3 is a block diagram of the engine control system, showing in a greater
part, an electronic control unit of Fig. 2.
[0030] [0030] Fig. 4 is a flowchart showing a process for determining whether or not a driving
condition is met, which is executed by a condition determiner of Fig. 3.
[0031] [0031] Fig. 5 is a flowchart showing a modification of the determination process
of Fig. 1.
DETAILED DESCRIPTION OF THE EMBODIMENT
[0032] [0032] Hereinafter, an embodiment of the present invention will be described with
reference to the drawings. Hereinafter, a motorcycle will be described as an example
of a vehicle, and the stated directions are referenced from the perspective of a driver
driving the motorcycle, unless otherwise explicitly noted.
[0033] [0033] Fig. 1 is a left side view of a motorcycle 1 including an engine control system
for a vehicle according to an embodiment of the present invention. Referring to Fig.
1, the motorcycle 1 includes a front wheel 2 and a rear wheel 3. The front wheel 2
is rotatably mounted to the lower end portion of a front fork 4 extending substantially
vertically. The upper end portion of the front fork 4 is coupled to a handle 6 including
a right and left grips via a steering shaft (not shown) rotatably supported by the
head pipe 5. When the driver grips the grips and rotates the handle 6, the front wheel
2 rotates around the steering shaft. The grip gripped by the driver's right hand is
a throttle grip 7 (see Fig. 2) which is rotated by twisting the driver's wrist to
operate a throttle device 17. A clutch lever 8 is provided in front of the grip gripped
by the driver's left hand.
[0034] [0034] A pair of right and left main frame members 9 extend rearward and downward
from the head pipe 5. A pair of right and left pivot frame members 10 are coupled
to the rear portions of the main frame members 9. The front end portions of swing
arms 11 extending substantially in the longitudinal direction of the motorcycle 1
are coupled to the pivot frame members 10, respectively such that each swig arm 11
is pivotable around the front end portion. An engine 14 is mounted to the main frame
members 9 and the pivot frame members 10. A driving power of the engine 14 is transmitted
to the rear wheel 3 via a transmission 15 and a chain 16. The throttle device 17 is
coupled to intake ports (not shown) of the engine 14, and an air cleaner 18 is coupled
to the throttle device 17. A straddle seat 13 which is straddled by the driver is
mounted behind the handle 6 such that a fuel tank 12 is interposed between them. An
electronic control unit 19 (controller) is accommodated into an inner space below
the seat 13 and is configured to control the operation of the engine 14.
[0035] [0035] Fig. 2 is a schematic view showing a configuration of the engine 14 and constituents
in the vicinity of the engine 14 and a configuration of the entire engine control
system 50 built into motorcycle 1 of Fig. 1. As shown in Fig. 2, the throttle device
17 includes an air-intake pipe 20 provided between the engine 14 and the air cleaner
18, a throttle valve 21 provided in an inner passage of the air-intake pipe 20, and
a valve actuator 22 for driving the throttle valve 21. The throttle valve 21 is driven
by the valve actuator 22 to open and close the inner passage of the air-intake pipe
20 such that its opening degree is variable, thereby controlling the amount of air
fed to the engine 14. The engine 14 is provided with a fuel injection device 23 and
an ignition device 24. The devices 23 and 24 operate at suitable timings so that ignition
and combustion occur in cylinders, thereby allowing the engine 14 to generate a driving
power.
[0036] [0036] The driving power of the engine 14 is transmitted to the rear wheel 3 via
a driving power transmission path 25. As shown in Fig. 2, the driving power transmission
path 25 includes an engine output shaft 26, a reduction gear mechanism 27, a clutch
28, a transmission input shaft 29, a transmission 15, a transmission output shaft
30, and a chain 16, in this order when viewed from the engine 14. The clutch 28 is
coupled to a clutch lever 8 via a wire 8a. In a state where the clutch lever 8 is
not operated, the clutch 28 is engaged to allow the driving power to be transmitted
between the reduction gear mechanism 27 and the transmission input shaft 29, while
in a state where the clutch lever 28 is operated, the clutch 28 is disengaged by the
operation of the wire 8a not to permit the driving power to be transmitted between
the reduction gear mechanism 27 and the transmission input shaft 29. The transmission
15 changes the speed of the rotation of the transmission input shaft 28 and transmits
the resulting rotation to the transmission output shaft 30. The transmission 15 is,
for example, a dog clutch type multi-stage transmission including a plurality of gear
trains arranged in parallel. The transmission 15 is configured to select one from
among a plurality of gears. The transmission gears include a plurality of forward
transmission gears which are different in gear ratio and a neutral gear for inhibiting
transmission of the driving power between the transmission input shaft 29 and the
transmission output shaft 30. The transmission gear is set and changed by operating
a shift pedal (not shown) to shift a gear position.
[0037] [0037] The electronic control unit 19 is configured to receive signals from sensors
for detecting driving states as inputs and control the engine 14 and the associated
devices in accordance with the detected driving states and the set control mode. The
electronic control unit 19 is configured to selectively set one from among the plurality
of control modes. In this embodiment, the control modes which can be set in the electronic
control unit 19 includes two control modes which are a normal mode and an economy
mode for allowing the engine 14 to operate with a smaller fuel amount than in the
normal mode. The electronic control unit 19 is configured to turn ON and OFF the economy
mode. To be specific, control maps corresponding to respective control modes are pre-stored
in the electronic control unit 19, and the electronic control unit 19 is configured
to obtain operation command values of the engine 14 and the associated devices with
reference to these control maps. The control mode switches according to the switching
of the control map to be referred to.
[0038] [0038] As shown in Fig. 2, sensors coupled to the inputs of the electronic control
unit 19 include a grip position sensor 31 for detecting an operation position of the
throttle grip 7, a throttle valve position sensor 32 (throttle valve opening degree
sensor) for detecting an opening degree of the throttle valve 21, an engine speed
sensor 33 for detecting an engine speed of the engine 14, a gear position sensor 34
for detecting a gear position of the transmission 15, a clutch operation switch 35
for detecting whether or not the clutch lever 8 has been operated, and a vehicle speed
sensor 36 for detecting a vehicle speed of the motorcycle 1. The electronic control
unit 19 is configured to detect a current gear set in the transmission 15 based on
the signal received from the gear position sensor 34 and to detect whether or not
the clutch 28 is disengaged based on the signal received from the clutch operation
switch 35. The vehicle speed sensor 36 is configured to detect the rotational speed
of the front wheel 2. The electronic control unit 19 is configured to execute predetermined
calculation based on the detection value from the vehicle speed sensor 36 to measure
the vehicle speed of the motorcycle 1. Alternatively, an acceleration sensor for detecting
acceleration, and a neutral gear position sensor for detecting that a neutral gear
is set in the transmission 15 may be communicatively coupled to the electronic control
unit 19, although not shown.
[0039] [0039] Furthermore, a mode select switch 37 (mode switching device) is communicatively
coupled to the input of the electronic control unit 19 to input a command for switching
the control mode to the electronic control unit 19. The mode select switch 37 is positioned
adjacent the grip of the handle 6 and easily operated by the driver during driving.
The mode select switch 37 may be a press-button switch, a toggle switch, or a rocker
switch, but the press-button switch is suitably used when the electronic control unit
19 performs the determination process using an input time determiner 41 (see Fig.
3) as described later.
[0040] [0040] As shown in Fig. 2, the components of the engine 14 which are coupled to the
outputs of the electronic control unit 19 include the valve actuator 22 of the throttle
device 17, the fuel injection device 23 and the ignition device 24.
[0041] [0041] A mode display device 38 is coupled to the output of the electronic control
unit 19 to display a control mode currently set. The mode display device 38 is attached
on an instrument panel (not shown) positioned in close proximity to the handle (see
Fig. 1) and can be visually checked by the driver during driving. The mode display
device 38 may be a suitable device such as a lamp, or a liquid crystal display.
[0042] [0042] An economy lamp 39 is coupled to the output of the electronic control unit
19 to display a state where the motorcycle 1 is driving under a fuel-efficient condition
when a current driving state is the fuel-efficient condition. The electronic control
unit 19 includes a fuel-efficient driving state determiner (not shown) configured
to determine whether or not the motorcycle 1 is driving under a fuel-efficient condition.
The fuel-efficient driving state determiner may be configured to determine whether
or not the engine speed falls within a predetermined numeric range, whether or not
a change amount of the engine speed falls within a predetermined range, whether or
not the opening degree of the throttle valve 21 falls within a predetermined opening
degree range, whether or not a change amount of the opening degree of the throttle
valve 21 falls within a predetermined range, whether or not the vehicle speed is higher
than zero, and whether or not the clutch lever 8 has been operated. If it is determined
as "YES" in at least one of determination steps, the fuel-efficient driving state
determiner detects that the motorcycle 1 is driving under the fuel-efficient condition
and turns ON the economy lamp 39. The driver can easily check the ON or OFF of the
economy lamp 39 provided on the instrument panel during driving, thereby facilitating
the fuel-efficient driving. Alternatively, the upper limit values and the lower limit
values defining the engine speed range and the opening degree range may be changed
according to the gear set in the transmission 15.
[0043] [0043] As described above, the engine control system 50 of this embodiment includes
the electronic control unit 19, the sensors 31 to 36 coupled to the inputs of the
electronic control unit 19, the mode select switch 37 coupled to the input of the
electronic control unit 19, the devices 22 to 24 of the engine 14 which are coupled
to the outputs of the electronic control unit 19, the mode display device 38 coupled
to the output of the electronic control unit 19, and the economy lamp 39 coupled to
the output of the electronic control unit 19.
[0044] [0044] Fig. 3 is a block diagram of the engine control system 50, showing in a greater
part, the electronic control unit 19 of Fig. 2. Referring to Fig. 3, the electronic
control unit 19 is configured to determine whether a command for switching the control
mode which has been input by the driver's operation of the mode select switch 37 is
valid or invalid, and switch the control mode if it is determined that the command
is valid. In accordance with the set control mode, the operations of the devices 22
to 24 and the operation of the mode display device 38 are controlled. For the control,
the electronic control unit 19 includes a memory 40, the input time determiner 41,
an abnormality determiner 42, a condition determiner 43, a mode setting section 44,
a throttle controller 45, a fuel controller 46, and an ignition controller 47. Hereinafter,
the command for switching the control mode is sometimes simply referred to as "command."
[0045] [0045] The control maps corresponding to the respective control modes are pre-stored
in the memory 40. These control maps are referred to in order to obtain the operation
amount of the valve actuator 22 corresponding to a target opening degree of the throttle
valve 21, the operation time of the fuel injection device 23 corresponding to a target
fuel amount of the fuel injected from the fuel injection device 23, and the operation
timing of the ignition device 24 corresponding to a target igniting timing.
[0046] [0046] When the mode select switch 37 is operated and the command for switching the
control mode is input to the electronic control unit 19, the input time determiner
41 determines whether or not the operation time (i.e., time period from the operation
starts until the operation ends) falls within a range from a predetermined first time
to a predetermined second time. If it is determined that the operation time falls
within this range, the input time determiner 41 determines that the command has been
input, whereas if it is determined that the operation time does not fall within this
range, the input time determiner 41 determines that the command has not been input.
In other words, the input time determiner 41 is configured to determine that the command
has been input, only when the mode select switch 37 has been operated for a long time
correctly. The predetermined first time is set to, for example, about one second and
the predetermined second time is set to, for example, about three seconds. This makes
it possible to prevent the control mode from being switched inadvertently by the fact
that something touches the mode select switch 37 by mistake or continues to contact
the mode select switch 37 for a long time. The electronic control unit 19 changes
a display content in the instrument panel when the operation time falls within the
range between the first time and the second time. This enables the driver to know
that the operation time falls within this predetermined range. If the driver wishes
to change the control mode, the driver must finish the operation of the mode select
switch 37 while the display content is changing, thereby preventing the operation
time from exceeding the second time.
[0047] [0047] The abnormality determiner 42 is configured to determine whether or not there
is an abnormality such as disconnection of signal lines in the sensors 31 to 36 coupled
to the inputs of the electronic control unit 19. Whether the input command is determined
as valid or invalid may be determined based on whether or not a predetermined driving
condition is met as described later. If there is an abnormality in the sensors 31
to 36, it is difficult to determine the driving condition correctly using the detection
values of the sensors 31 to 36. From this, the condition determiner 43 is configured
to determine whether the command is valid or invalid only when the abnormality determiner
42 determines that the sensors 31 to 36 are normal. If not, the switching of the control
mode is inhibited even when the input time determiner 41 determines that the command
has been input. This abnormality determination process is performed every time ignition
is ON, i.e., a command for starting-up the motorcycle 1 is input. If the abnormality
determiner 42 determines that there is an abnormality, this determination continues
and the switching of the control mode is inhibited until ignition is OFF, when a command
for stopping the motorcycle 1 is input. For example, if the abnormality of the sensors
is obviated after the ignition is ON, the switching of the control mode continues
to be inhibited. If it is determined that the sensors are normal when next ignition
is ON, then the condition determiner 43 determines whether the command is valid or
invalid.
[0048] [0048] The condition determiner 43 is configured to determine whether or not predetermined
driving conditions are met based on signals from the sensors 31 to 36 coupled to the
inputs of the electronic control unit 19, if the input time determiner 41 determines
that the command has been input and the abnormality determiner 42 determines that
the sensors 31 to 36 are normal. In this case, if the predetermined driving condition
is met, the condition determiner 43 determines that the command is valid, whereas
if the predetermined driving condition is not met, the condition determiner 43 determines
that the command is invalid. The driving condition relates to the driving states of
the vehicle at the time point when the mode switching command is input, and includes,
at least one of, for example, a vehicle speed, an engine speed, a gear ratio, and
a clutch state.
[0049] [0049] If the condition determiner 43 determines that the command is valid, the mode
setting section 44 reads out a control map corresponding to the switched control mode,
from the memory 40, whereas if the condition determiner 43 determines that the command
is invalid, the mode setting section 43 keeps the current control map.
[0050] [0050] When the control map read out is the control map corresponding to the economy
mode, the mode setting section 44 outputs a signal to the mode display device 38 to
cause the mode display device 38 to display representing that the control mode is
the economy mode. In a case the mode display device 38 is a lamp, for example, the
mode setting section 44 outputs a signal for turning ON the lamp when the economy
mode is set, while the mode setting section 44 outputs a signal for turning OFF the
lamp when the normal mode is set. In this way, the mode setting section 44 causes
the mode display device 38 to conduct display in a different manner according to the
set control mode. The driver sees the mode display device 38 to know the control mode
currently set. The driver can confirm that the command for switching the control mode
is valid, after the driver has operated the mode select switch 37.
[0051] [0051] The throttle controller 45, the fuel controller 46 and the ignition controller
47 obtain the operation amount of the valve actuator 22, the operation time of the
fuel injection device 23, and the ignition timing of the ignition device 24, respectively,
based on the inputs received from the sensors 31 to 36 coupled to the inputs of the
electronic control unit 19, with reference to the control map which has been read
by the mode setting section 27. The throttle controller 45, the fuel controller 46
and the ignition controller 47 drive the valve actuator 22, the fuel injection device
23 and the ignition device 24, respectively, according to the obtained operation command
values.
[0052] [0052] The control maps are designed according to the concepts of the control modes.
Therefore, the operation command values are sometimes different, depending on the
control maps, regardless of the same driving state, i.e., the same input. For example,
when the motorcycle 1 is driving in the economy mode and an acceleration request is
being made, a target fuel amount is set less or a change rate of the target fuel amount
is set lower than in the normal mode, because the control map designed to restrain
a fuel consumption amount is referred to in the economy mode. If the control mode
is switched under this driving state, the operation and output of the engine 14 (see
Fig. 2) may fluctuate and the driving state may fluctuate.
[0053] [0053] The condition determiner 43 is configured to determine that the predetermined
driving condition is met if a substantial driving state fluctuation does not occur
even when the control mode is switched, and permit the control mode from being switched
when the predetermined driving condition is met. This makes it possible to suppress
a driving state fluctuation and improve driving feel when the control mode is switched.
[0054] [0054] Fig. 4 is a flowchart showing a process for determining whether or not a driving
condition is met, which is executed by the condition determiner 43 of Fig. 3. The
determination process of Fig. 4 is carried out when the input time determiner 41 determines
that the command has been input and abnormality determiner 42 determines that the
sensors 31 to 35 are normal. Hereinafter, the reference characters will be referred
to suitably with reference to Figs. 1 to 3 as well as Fig. 4.
[0055] [0055] Referring to Fig. 4, the condition determiner 43 determines whether or not
the vehicle speed is 0 (step S1). If it is determined that the vehicle speed V is
not 0 (S1: NO), the process goes to step S2. On the other hand, if it is determined
that the vehicle speed V is 0 (S1: YES), the condition determiner 43 determines that
the driving condition is met, and determines that the command is valid (step S10).
[0056] [0056] The condition determiner 43 determines whether or not the vehicle speed V
falls within a speed range which is not less than a first vehicle speed
V1 larger than 0 and is less than a second vehicle speed
V2 higher than the first vehicle speed
V1 (step S2). If it is determined that the vehicle speed V falls within this speed range
(S2: YES), the process goes to step S3. On the other hand, if it is determined that
the vehicle speed V is outside this speed range (S2: NO), the condition determiner
43 determines that the driving condition is not met, and determines that the command
is invalid (step S20).
[0057] [0057] The condition determiner 43 determines whether or not acceleration α of the
motorcycle 1 is less than a first predetermined value α
1 which is a positive value (step S3). If it is determined that the acceleration α
is less than the first predetermined value α
1 (S3: YES), the process goes to step S4. If it is determined that the acceleration
α is not less than the first predetermined value α
1 (S3: NO), the condition determiner 43 determines that the driving condition is not
met, and determines that the command is invalid (step S20).
[0058] [0058] The condition determiner 43 determines whether or not the acceleration α is
more than a second predetermined value α
2 which is a negative value (step S4). In other words, in this step, it is determined
whether or not the deceleration falls within an allowable range. If the extent of
deceleration is relatively small and it is determined that the acceleration α is more
than the second predetermined value α
2 (S4: YES), the process goes to step S5. On the other hand, if the extent of deceleration
is relatively large and the acceleration α is not more than the second predetermined
value α
2 (S4: NO), the condition determiner 43 determines that the driving condition is not
met, and determines that the command is invalid (step S20).
[0059] [0059] As described above, in step S3 and step S4, the condition determiner 43 also
serves as an acceleration determiner configured to determine whether or not the acceleration
is the predetermined acceleration. In step S3 and step S4, the acceleration α may
be detected based on signals from an exclusive acceleration sensor (not shown), or
may be obtained by temporal differentiation of the vehicle speed detected by the signals
from the vehicle speed sensor 36.
[0060] [0060] Alternatively, by using the opening degree of the throttle valve 21 which
is detected by the throttle valve position sensor 32, a determination process similar
to the predetermined process using the acceleration α to be compared to the predetermined
value, can be performed. The motorcycle 1 may be typically accelerated when the opening
degree of the throttle valve 21 is larger than a set throttle valve opening degree
with which the motorcycle 1 can drive at a constant speed on a flat road. In view
of this, the acceleration α is calculated from a deviation between the set throttle
valve opening degree and the opening degree of throttle valve 21 which is detected
by the throttle valve position sensor 32. The calculated acceleration α may be compared
to the predetermined values α
1 and α
2 by utilizing a relationship in which the acceleration increases as the deviation
increases. In this case, the value of the set throttle valve opening degree may be
set and changed according to the engine speed and the transmission gear.
[0061] [0061] In the manner as described above, by using the vehicle speed or the throttle
valve opening degree, the engine speed and the transmission gear, a sensor exclusive
for detection of the acceleration may be omitted. As a result, the number of components
and a manufacturing cost are reduced.
[0062] [0062] The condition determiner 43 determines whether or not the driving power transmission
path 25 is disconnected (step S5). As defined herein, the state where the driving
power transmission path 25 is disconnected refers to a state where the driving power
of the engine 14 is not transmitted to the rear wheel 3 which is a driving wheel of
the motorcycle 1, and includes, for example, a state where the clutch 28 is disengaged
not to permit the driving power to be transmitted or a state where the neutral gear
is set in transmission 15. If it is determined that the driving power transmission
path 25 is disconnected (S5 :YES), the condition determiner 43 determines that the
driving condition is met and the command is valid (step S10). On the other hand, if
it is determined that the driving power transmission path 25 is connected (S5: NO),
the process goes to step S6.
[0063] [0063] As described above, in the state where the clutch 28 is disengaged or the
state where the neutral gear is set in the transmission 15, the driving power transmission
path 25 is disconnected. Therefore, when it is determined that the clutch operation
switch 35 detects that the clutch lever 8 has been operated or the gear position sensor
34 detects that the neutral gear is set in the transmission 15, it may be determined
that the driving power transmission path 25 is disconnected. On the other hand, when
it is determined that the clutch operation switch 35 detects that the clutch lever
8 has not been operated or the gear position sensor 34 detects that a gear other the
neutral gear is set in the transmission 15, it may be determined that the driving
power transmission path 25 is connected.
[0064] [0064] In step S6, the condition determiner 43 determines whether or not a transmission
gear ratio
r in the transmission 15 is less than a predetermined reduction gear ratio
rx which is not more than a maximum reduction gear ratio
r1 which can be set. If it is determined that the transmission gear ratio
r is less than the predetermined reduction gear ratio
rx (S6: YES), the condition determiner 43 determines that the driving condition is met
and determines that the command is valid (step S10). On the other hand, if it is determined
that the transmission gear ratio r is not less than the predetermined reduction gear
ratio
rx (S6: NO), the condition determiner 43 determines that the driving condition is not
met and determines that the command is invalid (step S20).
[0065] [0065] The maximum reduction gear ratio
r1 which can be set, which is used in step S6 means a reduction gear ratio in a first
gear which is the lowest gear. The predetermined reduction gear ratio
rx may be set to, for example, a reduction gear ratio in a second gear. In this example,
if a third gear or higher gear is set in the transmission 15, the process goes to
step S10, whereas if a second gear or lower gear is set in the transmission 15, the
process goes to step S20. That is, in step S6, it is determined whether or not a current
gear set in the transmission 15 which is capable of selecting any one gear position
from among a plurality of forward gears is less than a predetermined gear. Therefore,
the condition determiner 43 is configured to perform the determination process based
on the gear position detected by the gear position sensor 34 without performing a
process for calculating the reduction gear ratio.
[0066] [0066] As explained above, the condition determiner 43 of this embodiment determines
that the command is valid if the motorcycle 1 is in a stopped state (step S1). A driving
state fluctuation will not occur if the control mode is switched in the stopped state.
Therefore, the control mode can be switched without affecting the driving feel.
[0067] [0067] If it is determined that the vehicle speed V is more than 0 and does not fall
within the predetermined speed range, the condition determiner 43 determines that
the command is invalid (step S2). The first vehicle speed
V1 which is the lower limit value of the speed range, which is used in step S2, is a
speed set in a starting range, and may be set to a vehicle speed corresponding to
for example, a first gear, and corresponding to an engine speed at which an output
torque is higher, for example, 20km/h. The second vehicle speed
V2 which is the upper limit value of the speed range may be set to a speed at which
restricting a fuel consumption amount under engine control does not substantially
occur. Under this setting, if the vehicle speed
V is lower and outside the speed range, switching of the control mode in the starting
range in which acceleration is required is inhibited and a driving state fluctuation
due to the switching of the control mode can be prevented. If the vehicle speed
V is higher and outside the speed range, the switching of the control mode will not
be effective. Therefore, occurrence of an unnecessary switching operation in this
situation is prevented. During the starting, the switching of the normal mode to the
economy mode is inhibited, and the motorcycle 1 can start with a higher output torque
than in the economy mode. This can reduce a time that lapses from the motorcycle 1
has started until the vehicle speed reaches a speed at which the motorcycle 1 can
drive in a stable state, and hence improves convenience.
[0068] [0068] If it is determined that the motorcycle 1 is in a transient state in which
the motorcycle 1 is not driving at a constant speed, the condition determiner 43 determines
that the command is invalid (step S3, S4). In this transient state, there is a chance
that a target fuel amount is different between the control modes regardless of the
same input, and as a result, a propulsive force applied to the rear wheel 3 is different,
causing a difference in actual speed and actual acceleration speed. Since it is determined
that the command is invalid in the transient state, driving state fluctuation due
to the switching of the control mode can be suppressed.
[0069] [0069] If the deceleration is larger, the condition determiner 43 determines that
the command is invalid (step S4). Therefore, the switching of the control mode is
inhibited in the driving state in which an engine brake is operating, for example.
As a result, the driving state fluctuation which would be caused by the switching
of the control mode, does not occur in the state where the engine brake is operating.
[0070] [0070] In step S3 and step S4, it is determined whether or not the driving state
is the transient state, and it is determined that the command is invalid if the driving
state is the transient state. In other words, in step S3 and S4, it is determined
whether or not the motorcycle 1 is driving at a substantially constant speed and it
is determined that the command is not invalid if it is determined that the motorcycle
1 is driving at a substantially constant speed. The speed change due to the switching
of the control mode can be made less when the motorcycle 1 is driving at a substantially
constant speed than in the state where the driving state is the transient state, and
the control mode can be switched without worsening driving feel. The first predetermined
value α
1[m/s
2] may be set to a range of, for example, 0 < α
1 < 5. The second predetermined value α
2[m/s
2] may be set to a range of, for example, -5 < α
2 < 0. To determine whether or not the motorcycle 1 is driving at a constant speed,
the predetermined values α
1 and α
2 used in steps S3 and S4 may be set to a value near 0.
[0071] [0071] The condition determiner 32 determines that the command is valid if it is
determined that the driving power transmission path 25 is disconnected (step S5).
In the state where the driving power transmission path 25 is disconnected, a change
in the operation of the engine 14 due to the switching of the control mode is less
likely to be transmitted to the rear wheel 3. This reduces a chance that a substantial
driving state fluctuation occurs. Therefore, in this case, the switching of the control
mode is permitted, and the control mode can be switched without worsening the driving
feel during driving.
[0072] [0072] The condition determiner 32 determines that the command is invalid if it is
determined that the driving power transmission path 25 is connected and the forward
transmission gear set in the transmission 15 is a lower gear, whereas the condition
determiner 32 determines that the command is valid if it is determined that the driving
power transmission path 25 is connected and the forward transmission gear is a medium
or high gear (step S6). When the lower gear is set in the transmission 15, typically,
a torque transmitted from the engine 14 to the rear wheel 3 is large, and acceleration
is required, for example, during starting. In these cases, the switching of the control
mode is inhibited. Therefore, the driving state fluctuation due to the switching of
the control mode can be suppressed and the motorcycle 1 can start with the driving
state fluctuation lessened.
[0073] [0073] As described above, the condition determiner 43 determines whether the command
is valid or invalid based on whether or not the current driving state meets any of
the plurality of driving conditions, and the control mode is switched without worsening
the driving feel if it is determined that the command is valid.
[0074] [0074] During driving, it is determined that the command is valid when all of the
three driving conditions in step S2 to S4 are met and then either one of the two driving
conditions in step S5 and S6 is met. Since the switching of the control mode is permitted
when the various driving conditions are met, the driving state fluctuation due to
the switching of the control mode can be suppressed sufficiently.
[0075] [0075] The flow of the determination process executed by the condition determiner
43 is not limited to the flow of Fig. 4. Fig. 5 is a flowchart showing modification
of the determination process. In the flow chart of modification of Fig. 5, a determination
step regarding the vehicle speed (step S102) is changed as compared to the flowchart
of Fig. 4 (also see step S2 in Fig. 4). In step S102, it is determined whether or
not the vehicle speed V is not less than the first vehicle speed
V1 which is more than 0. If it is determined that the vehicle speed
V is not less than the first vehicle speed
V1 (S102: YES), the process goes to step S3. On the other hand, if it is determined
that the vehicle speed V is less than the first vehicle speed
V1 (S102: NO), the process goes to step S5. In step S3, the determination step similar
to that shown in Fig. 4 is performed, and if it is determined that the acceleration
α is less than the first predetermined value α
1 (S3: YES), the process goes to step S4, whereas if it is determined that the acceleration
α is not less than the first predetermined value α
1 (S3: NO), the process goes to step S5. In step S4, the determination step similar
to that of Fig. 4 is performed. If it is determined that the acceleration α is more
than the second predetermined value α
2 (S4: YES), the process goes to step S10 and it is determined that the command is
valid. On the other hand, if it is determined that the acceleration α is not more
than the second predetermined value α
2 (S4: NO), the process goes to step S5. In step S5, the determination step similar
to that of Fig. 4 is performed. If it is determined that the driving power transmission
path 25 is disconnected (S5 :YES), the process goes to step S10, whereas if it is
determined that the driving power transmission path 25 is not disconnected (S5 :NO),
the process goes to step S20, and it is determined that the command is invalid.
[0076] [0076] As described above, in this modification, if either one of the driving conditions
that the motorcycle 1 is driving at a substantially constant speed (step S3 and step
S4), and the driving power transmission path 25 is disconnected (step S5), the command
for switching the control mode is permitted. As described above, if the driving power
transmission path 25 is disconnected, there is a small chance that a change in the
operation of the engine 14 is transmitted to the rear wheel 3 and causes driving state
fluctuation. In the determination step of step S102, it is determined that the command
is valid even when the vehicle speed
V falls within the high-speed range.
[0077] [0077] In modification of the determination process of Fig. 4, all of the steps S1
to S6 of Fig. 4 need not be performed. For example, step S6 of Fig. 4 is omitted from
the flow of Fig. 5. Although it is determined that the command is not invalid when
the vehicle speed
V falls within the high-speed range (step S102) in the flowchart of Fig. 5, steps S2
and S102 may be omitted if it is determined that the command is not invalid when the
vehicle speed
V falls within the starting range. In a further alternative, it may be determined that
the command is valid if at least one of the plurality of driving conditions defined
in the steps shown in Figs. 4 and 5 is met.
[0078] [0078] The driving state fluctuation associated with fluctuation in the engine driving
power which is caused by the switching of the control mode tends to occur in a relatively
lightweight straddle-type vehicle such as the motorcycle 1. For this reason, the application
of the engine control system 50 of this embodiment to the straddle-type vehicle will
be very effective. The straddle-type vehicle includes a personal watercraft, a buggy,
etc, in addition to the motorcycle.
[0079] [0079] Although the embodiment of the present invention has been described, the above
configuration may be changed within a scope of the present invention.
[0080] [0080] A display device for displaying a reason why the mode switching command is
invalid may be coupled to the output of the electronic control unit 19 and may be
attached on the instrument panel. Furthermore, the display device may be configured
to display a different content according to the reason when the electronic control
unit 19 determines that the mode switching command is invalid based on the driving
condition. In this case, the driver can know the reason why the mode switching command
is invalid, and convenience is improved.
[0081] [0081] Regarding determination as to whether or not the driving condition is met,
the mode switching command need not be determined as invalid during deceleration of
the motorcycle 1. In other words, the determination step S4 may be omitted from the
flowchart of the determination process shown in Figs. 4 and 5.
[0082] [0082] Although in the above embodiment, the determination step for the driving condition
regarding negative acceleration is performed in step S4, a step for determining whether
or not the engine brake is operating to decelerate the motorcycle 1 may be added to
this determination step. To be specific, it may be determined whether or not a brake
operation member has been operated and a current engine speed is higher than an engine
speed in a state where a throttle grip is closed, based on the detection values from
the engine speed sensor and the brake sensor. If it is determined as YES, it may be
determined that the engine brake is operating to decelerate the motorcycle 1. It may
be determined that the driving condition is not met if the acceleration α of the vehicle
is not more than the second predetermined value α
2, after it is determined that the engine brake is operating. This makes it possible
to inhibit the switching of the control mode during the engine braking operation in
which the driving state fluctuation due the switching of the control mode tends to
occur, and to permit the switching of the control mode during deceleration of the
motorcycle 1 other than a state where the engine brake is operating. Thus, convenience
is improved.
[0083] [0083] When the ignition switch is tuned ON and the engine re-starts without inputting
the command for switching the control mode with the mode select switch in a case where
the ignition switch is turned OFF and the engine is stopped in the economy mode, the
mode setting section may set the normal mode at the re-start. When the ignition switch
is tuned ON and the engine re-starts after the command for switching the control mode
to the economy mode is input with the mode select switch, the mode setting section
may set the economy mode at the re-start.
[0084] [0084] Although switching between ON and OFF of the economy mode has been described
above, the switching of the control mode may be permitted in the same manner only
when a predetermined driving condition is met, in a case where switching between ON
and OFF of two or mode control modes regarding the driving state, from among a power
restricting mode, a CBS (combination breaking system) mode, a race mode (also called
sport mode), a highway mode, a supercharger activation mode, a traction control, and
others, occurs, and thereby, the driving state fluctuation due to the switching of
the control mode can be suppressed. As should be readily appreciated, the present
invention is suitably applicable to switching between ON and OFF of a plurality of
control modes. Although in the above embodiment, two control modes which are different
in engine driving power property has been described, switching between ON and OFF
of three or more control modes may be permitted according to the driving condition.
The present invention is applicable in the same manner to a case where the control
mode is automatically switched as well as a case where the control mode is switched
in response to the command input by the driver. The present invention is applicable
to a case where the operation command value is changed continuously as well as to
a case where the operation command value is obtained discontinuously after switching
of the control mode.
[0085] [0085] The configuration of the engine 14 and the configuration of the transmission
15 are not limited to those described above. The engine control system for the vehicle
of the present invention is applicable to other vehicles such as four-wheeled vehicles
and all terrain vehicles (ATVs) as well as motorcycles and straddle-type vehicles.
[0086] [0086] As described above, the engine control system of the present invention has
an advantage that driving feel is improved, and is applicable to vehicles such as
motorcycles and others which can effectively use the present invention.