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EP 2 710 253 B1 |
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EUROPEAN PATENT SPECIFICATION |
(45) |
Mention of the grant of the patent: |
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15.04.2015 Bulletin 2015/16 |
(22) |
Date of filing: 11.05.2012 |
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(51) |
International Patent Classification (IPC):
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(86) |
International application number: |
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PCT/FI2012/050455 |
(87) |
International publication number: |
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WO 2012/156584 (22.11.2012 Gazette 2012/47) |
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MULTI-CYLINDER PISTON ENGINE
MEHRZYLINDER BRENNKRAFTMASCHINE
MOTEUR MULTICYLINDRES
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Designated Contracting States: |
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AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL
NO PL PT RO RS SE SI SK SM TR |
(30) |
Priority: |
17.05.2011 FI 20115471
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Date of publication of application: |
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26.03.2014 Bulletin 2014/13 |
(73) |
Proprietor: Wärtsilä Finland Oy |
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65380 Vaasa (FI) |
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(72) |
Inventor: |
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- SUNDSTEN, Magnus
FI-65610 Korsholm (FI)
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(74) |
Representative: Berggren Oy Ab |
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P.O. Box 16
Antinkatu 3 C 00101 Helsinki 00101 Helsinki (FI) |
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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Technical field of the invention
[0001] The present invention relates to a multi-cylinder piston engine in accordance with
the preamble of claim 1. The engine comprises a starting arrangement and at least
one cam-operated valve lifting device for each cylinder of the engine, the valve lifting
device being arranged to open a gas exchange valve.
Background of the invention
[0002] Large internal combustion engines that are used for instance as main or auxiliary
engines in ships or for producing electricity and/or heat at power plants are usually
started by using pressurized air that is injected sequentially into the cylinders
of the engine for rotating the crankshaft. It is desirable to minimize the consumption
of starting air in order to save energy and the space needed for storing the starting
air, and therefore accurate control of the air injection timing is needed.
[0003] Patent application
WO 2007/003693 A1 discloses a starting system for a multi-cylinder piston engine. A pipe system connects
a pressure medium source to each cylinder of the engine. Each cylinder is provided
with a starting air valve for introducing pressure medium into the cylinders. Each
starting valve is controlled by a control valve. The starting system is provided with
timing equipment comprising a control part being in mechanical connection with a rotating
part of the engine. This kind of starting arrangement guarantees accurate timing of
the starting air injection, but a drawback is that control air has to be brought to
each control valve in a separate control air pipe. Also, different timing equipment
needs to be designed for engines with different number of cylinders.
[0004] Document
DE 4322585 A1 discloses control valves for starting valves actuated by specific cams having a flat
part.
Summary of the invention
[0005] The object of the present invention is to provide an improved multi-cylinder piston
engine with a starting arrangement. The engine according to the present invention
is characterized by the characterizing part of claim 1.
[0006] According to the present invention, the multi-cylinder piston engine comprises at
least one cam-operated valve lifting device for each cylinder of the engine, the valve
lifting device being arranged to open a gas exchange valve. The starting arrangement
comprises a pressure medium source, at least one starting valve for introducing pressure
medium into a cylinder of the engine, means for connecting the pressure medium source
to the starting valves, and a control valve for each cylinder of engine that is provided
with a starting valve for controlling the operation of the starting valve. Each control
valve is arranged to be operated by a gas exchange cam of the respective cylinder.
[0007] The invention has several advantages. Since the starting valves are controlled by
the gas exchange cams, a separate starting cam is not needed. Identical cams can be
used regardless of the cylinder number of the engine and there is no need to design
different starting cams for engines with different number of cylinders. Starting air
can be distributed to the cylinders in a single starting air duct instead of separate
ducts for each cylinder. This saves both space and material. The invention also enables
reliable and accurate control of starting air injection.
[0008] According to an embodiment of the invention, each gas exchange cam that operates
a control valve comprises a portion that is arranged below the base circle of the
cam for operating the control valve. When the control valve is operated by a portion
of the gas exchange cam that is under the base circle of the cam, a simple and reliable
control mechanism can be achieved. Identical cams can be used for engines with different
number of cylinders and no separate adjustment is needed for the starting air injection
timing.
[0009] According to an embodiment of the invention, each control valve is in flow communication
with the pressure medium source and the respective starting valve via a control air
duct.
[0010] According to an embodiment of the invention, the control valve is arranged to allow
pressure medium flow to the starting valve for opening the starting valve when the
valve lifting device is engaged with the portion of the gas exchange cam that is below
the base circle of the cam.
[0011] According to an embodiment of the invention, each control valve comprises a valve
member that is movable by the valve lifting device.
[0012] According to an embodiment of the invention, the valve lifting device comprises a
plunger pushing the valve member towards the gas exchange cam when the valve lifting
device is engaged with the portion of the gas exchange cam that is below the base
circle of the cam.
[0013] According to an embodiment of the invention, the valve member is pushed towards the
valve lifting device by the pressure of the pressure medium.
[0014] According to an embodiment of the invention, the gas exchange cam is an intake cam.
Starting air injection is started near top dead center and terminated close to the
crank angle where the exhaust valve opens. When the intake cam is used for controlling
the starting valve, the portion of the cam that is below the base circle is far from
the lobe of the cam. The shape of the portion below the base circle is thus not dependent
on the shape of the lobe. If the portion below the base circle is close to the lobe
of the cam, there might be some limitations to the shape of the portion below the
base circle.
[0015] According to an embodiment of the invention, each intake cam comprises a second portion
that is arranged below the base circle of the cam for controlling the operation of
variable intake valve closing, and the portion that is arranged below the base circle
of the cam is arranged also below the said second portion.
[0016] According to an embodiment of the invention, the gas exchange cam is an exhaust cam.
When the control valves are operated by the exhaust cams, the invention can be used
even in two-stroke engines with cam-operated exhaust valves.
[0017] According to an embodiment of the invention, in a two-stroke engine at least three
cylinders of the engine are provided with a starting valve and in a four-stroke engine
at least five cylinders of the engine are provided with a starting valve.
[0018] According to an embodiment of the invention, all the cylinders of the engine are
provided with a starting valve. Since identical cam profiles and valve lifting devices
can be used for all the cylinders of the engine, it is practical to provide all the
cylinders with starting valves.
[0019] According to an embodiment of the invention, each control valve comprises an inlet
channel for introducing pressure medium into the control valve, an outlet channel
for introducing the pressure medium to the starting valve for opening the starting
valve, and a drain channel for releasing the pressure medium out of the control valve
when the control valve is not actuated by the gas exchange cam.
[0020] According to an embodiment of the invention, the starting arrangement comprises a
main starting valve for initiating starting of the engine.
Brief description of the drawings
[0021]
Fig. 1 shows schematically a starting system of an internal combustion engine.
Fig. 2 shows a simplified cross-sectional view of a part of a cylinder head with gas
exchange valves and a starting valve.
Figs. 3-6 show an intake cam of the engine and the control arrangement of a starting
valve at different stages of operation according to an embodiment of the invention.
Fig. 7 shows an intake cam of the engine and the control arrangement of a starting
valve according to another embodiment of the invention.
Fig. 8 shows schematically a starting system of an internal combustion engine according
to another embodiment of the invention.
Fig. 9 shows an exhaust cam of the engine and a control arrangement of an air injection
valve.
Figs. 10 shows the vertical position of the cam followers at different crank angles.
Figs. 11 shows the vertical position of the cam followers at different crank angles
in an engine with VIC.
Detailed description of the invention
[0022] Embodiments of the present invention are now described in more detail with reference
to the accompanying drawings.
[0023] Fig. 1 shows schematically a starting arrangement of a piston engine 20. In the example
of Fig. 1, the engine 20 comprises six cylinders 19, but the engine 20 could comprise
any reasonable number of cylinders 19 arranged for instance inline or in a V-configuration.
The engine 20 is a large internal combustion engine, such as those used for producing
electricity and/or heat at a power plant or as main or auxiliary engines in ships.
In the embodiment shown in Fig. 1, all the cylinders 19 are provided with means for
introducing pressure medium, such as pressurized air, into the cylinders 19 for starting
the engine 20. However, in an engine with a large number of cylinders it is not necessary
that all the cylinders of the engine are used for starting. In case of a four-stroke
engine, starting air injection into at least five of the cylinders is needed to be
able to start the engine irrespective of the initial crankshaft position. In a two-stroke
engine, three cylinders suffice. If the engine is provided with means for rotating
the crankshaft into a better starting position, even a smaller number of cylinders
with starting air injection is sufficient. However, since the starting arrangement
according to the present invention enables using of identical means for injecting
starting air into each cylinder 19 of the engine 20, it is practical to use all the
cylinders 19 of the engine 20 for starting.
[0024] Pressurized air is stored in a starting air tank 18, from which it can be introduced
into the cylinders 19 of the engine 20 in a starting air duct 26. Instead of air,
also some other pressurized gas could be used. The starting air tank 18 can be filled
by a compressor (not shown). Each cylinder 19 of the engine 20 that is used for starting
is provided with a starting valve 10. In figure 2 is shown a starting valve 10 in
connection with a cylinder head 23. The cylinder head 23 is also provided with an
intake duct 32 for introducing combustion air into the respective cylinder 19, and
with an exhaust duct 33 for guiding exhaust gases out of the cylinder 19. One or more
intake valves 24 and one or more exhaust valves 25 are arranged in the cylinder head
23 for opening and closing the connection between the cylinder 19 and the intake and
exhaust ducts 32, 33. The operation of each starting valve 10 is controlled by a respective
control valve 12. Each cylinder 19 of the engine 20 can also be provided with more
than one starting valves 10. If each cylinder 19 is provided for instance with two
starting valves 10, both valves 10 can be controlled by the same control valve 12.
The control valves 12 are connected to the starting air duct 26. The starting air
duct 26 is provided with a main starting valve 17 for controlling when the engine
20 is started. An example of the starting valve 10 and the control valve 12 is shown
as a simplified illustration in Figs. 3-6.
[0025] According to an embodiment of the present invention, the starting arrangement comprises
a valve lifting device 4 and a gas exchange cam 1. The gas exchange cam 1 is shown
in the figures as being rotated 90 degrees around its vertical axis to better illustrate
the cam profile 2. The cam profile 2 of the gas exchange cam 1 comprises a base circle
2a, a lobe 2b and a portion 2c that is arranged below the base circle 2a. The expression
"below the base circle" means that the radius of that portion of the cam profile 2
is smaller than the radius of the base circle 2a. The radius of the portion 2c below
the base circle 2a does not need to be constant over the whole portion 2c. In the
embodiment shown in Figs. 3-6, the gas exchange cam 1 is an intake cam and the valve
lifting device 4 is arranged to open an intake valve 24 of the engine 20. An identical
cam lifting device 4 can be used for opening an exhaust valve 25 of the engine 20.
[0026] The cam lifting device 4 comprises a body part 5 and a reciprocating plunger 6 that
is arranged inside the body part 5. The plunger 6 is arranged to lift a push rod 8.
A cam follower 3 is attached to the plunger 6 with a bearing. A coil spring 7 between
the body part 5 and the plunger 6 pushes the cam follower 3 against the cam profile
2. The lifting arrangement works in a conventional manner. When the cam follower 3
is on the portion 2c of the cam profile 2 that is below the base circle 2a, the plunger
6 is at its lowest position. The body part 5 is provided with a stopper surface 9,
against which the push rod 8 can rest so that the position of the push rod 8 and the
intake valve 24 does not change when the cam follower 3 leaves the base circle 2a
and enters the portion 2c below the base circle 2a, or vice versa. When the intake
cam 1 is rotated, the cam follower 3 becomes eventually engaged with the lobe 2b of
the cam profile 2. The plunger 6 and the push rod 8 are moved upwards and the intake
valve 24 is opened. In figure 4 is shown the situation where the intake valve 24 is
fully open.
[0027] Each cylinder 19 of the engine 20 is provided with a starting valve 10 comprising
a valve member 22. The starting valve 10 is kept closed by a spring 11. For controlling
the operation of the starting valves 10, each valve lifting device 4 is provided with
a control valve 12. When the cam follower 3 is engaged with the portion 2c of the
cam profile 2 that is below the base circle 2a, the plunger 6 pushes a valve member
13 inside the control valve 12 downwards, as shown in Fig. 5.
[0028] For starting the engine 20, the main starting valve 17 is opened. This allows the
starting air to flow in the starting air duct 26 to the control valves 12. The pressurized
air enters the control valves 12 via inlet channels 14. In those control valves 12
that are in connection with a valve lifting device 4 where the cam follower 3 is on
the base circle 2a or the lobe 2b of the intake cam 1, the air pressure pushes the
valve member 13 inside the control valve 12 upwards into the position shown in Fig.
4. The valve member 13 thus allows the pressurized air to flow out of the control
valve 12 through a drain channel 16. The air is released from the drain channel 16
for instance into the engine room. By contrast, in those control valves 12 which are
in connection with a valve lifting device 4 where the cam follower 3 is on the portion
2c below the base circle 2a of the intake cam 1, the plunger 6 pushes the valve member
13 downwards, as shown in Fig. 5. This closes the connection between the inlet channel
14 and the drain channel 16 and the starting air flows to the starting valve 10. The
air is introduced through a control air inlet 27 into the space above the valve member
22 of the starting valve 10 and the air pressure pushes the valve member 22 downwards
and opens the starting valve 10. The starting air can thus flow in the starting air
duct 26 from the starting air tank 18 to the starting valve 10 and through a starting
air inlet 28 into the cylinder 19 of the engine 20, where it pushes the piston downwards
and rotates the crankshaft of the engine 20. When the camshaft rotates further, the
cam follower 3 leaves the portion 2c below the base circle 2a of the cam profile 2
of the intake cam 1 and enters again the base circle 2a. The pressure in the inlet
channel 14 and the pressure created by the valve member 22 of the starting valve 10
when being pushed upwards by the spring 11 can thus push the valve member 13 upwards
inside the control valve 12. Consequently, the connection between the outlet channel
15 and the drain channel 16 of the control valve 12 opens again, as can be seen in
Fig. 6, and starting air injection into the respective cylinder 19 is terminated.
Starting air is injected sequentially into the cylinders 19 of the engine 20 until
the engine 20 starts. When the engine 20 starts, the main starting valve 17 can be
closed.
[0029] With a different cam profile 2, where the portion 2c below the base circle 2a is
in a different position, those cam lifting devices 4 that are used for opening the
exhaust valves 25 could also be used for controlling the starting valves 10. However,
it is beneficial to use the intake cams for this purpose, since the portion 2c below
the base circle 2a can be arranged far from the lobe 2b of the cam profile 2. This
ensures smooth operation of the cam lifting devices 4 and the control valves 12.
[0030] In figure 7 is shown a slightly different embodiment of the invention. In this embodiment,
the push rod 8 is moved by a piston 30 that is arranged between the push rod 8 and
the plunger 6. A second spring 29 for eliminating clearance between the push rod 8
and the piston 30 is arranged between the piston 30 and the plunger 6. When the cam
follower 3 engages with the portion 2c of the cam profile 2 that is below the base
circle 2a of the cam profile 2, a gap 31 is formed between the plunger 6 and the piston
30. The second spring 29 keeps the piston 30 against the end of the push rod 8 so
that no gap is formed between the push rod 8 and the piston 30 or between the upper
end of the push rod 8 and the rocker arm. This ensures smooth operation of the valve
lifting device 4.
[0031] In figure 10 is shown as a graph the position of the cam follower 3. The broken line
shows the position of the cam follower of the exhaust valve 25 and the solid line
the position of the cam follower of the intake valve 24. Also the plungers 6 follow
the same curves. The push rods 8 and the valve lifts also follow the same curves with
the exception that because of the stopper surface 9 in the embodiment of figures 3-6
or the piston/spring arrangement 29, 30 in the embodiment of figure 7, the vertical
position of the push rods 8 cannot be negative. The area below the horizontal axis
indicates how the cam follower 3 of the intake valve lifting device 4 is engaged with
the portion 2c below the base circle 2a. The starting air injection takes place during
this phase, which starts in the embodiments shown in the figures just before top dead
center (TDC) during the compression stroke and lasts until approximately 90 degrees
of crank angle after top dead center during the power stroke.
[0032] In figure 11 is shown the vertical positions of the cam followers in an engine that
is provided with variable intake valve closing (VIC). In this embodiment, the intake
cam profile comprises a portion that is arranged below the base circle for controlling
the intake valve closing timing. Another portion for controlling the starting valves
is arranged below the portion that controls the intake valve closing timing.
[0033] In figure 8 is shown another embodiment of the invention, where the starting air
duct 26 and the starting air tank 18 are also used for introducing additional combustion
air into the cylinders 19 of the engine 20. The term "additional combustion air" refers
here to air that is introduced into the cylinders 19 of the engine 20 before ignition
but after the normal air intake has ended. In a four-stroke engine this means that
the additional combustion air is introduced into a cylinder 19 after closing of the
intake valves of that cylinder 19. Additional combustion air can be introduced into
the cylinders 19 of the engine 20 for reducing turbo lag in situations where the engine
load suddenly increases. In the embodiment of figure 8, the engine 20 is provided
with a control air duct 21 that connects the control valves 12 to the starting air
tank 18. The main starting valve 17 is arranged in the control air duct 21. The starting
air duct 26 is provided with a closing valve 34. Each cylinder 19 of the engine 20
is provided with a second control valve 12' for controlling the injection of the additional
combustion air into the cylinders 19. The second control valves 12' are connected
with a second control air duct 21' to the starting air tank 18. The second control
air duct 21' is provided with an air injection control valve 17' for controlling when
the injection of the additional combustion air is switched on. In the embodiment of
figure 8, the starting valves 10 are used also for introducing the additional combustion
air into the cylinders 19. However, also separate valves could be used. The control
air duct 21 is provided with a check valve 32 downstream from each control valve 12
for preventing the additional combustion air from escaping through the respective
control valve 12 when additional combustion air is introduced into the engine 20.
Similarly, the second control air duct 21' is provided with a second check valve 32'
downstream from each second control valve 12' for preventing the starting air from
escaping through the second control valve 12' during starting of the engine 20.
[0034] The second control valves 12' are operated by the exhaust cams 1' of the engine 20,
as shown in figure 9. The valve lifting devices 4 that are used for opening the exhaust
valves 25 can be identical with the valve lifting devices 4 that are used for opening
the intake valves 24. The cam profile 2' of the exhaust cam 1' is different from the
cam profile 2 of the intake cam 1, but otherwise the second control valves 12' are
operated in the same manner as the first control valves 12. It is beneficial to use
the exhaust cams 1' for operating the second control valves 12' since in the exhaust
cams 1' the portion 2c' below the base circle 2' can be arranged far from the lobe
2b' of the cam profile 2'. However, it would also be possible to use the intake cams
1 for operating the second control valves 12' and the exhaust cams 1' for operating
the first control valves 12. The second control valves 12' are identical to the first
control valves 12, comprising a valve member 13', an inlet channel 14', an outlet
channel 15', and a drain channel 14'.
[0035] It will be appreciated by a person skilled in the art that the invention is not limited
to the embodiments described above, but may vary within the scope of the appended
claims.
1. A multi-cylinder piston engine (20) comprising at least one cam-operated valve lifting
device (4) for each cylinder (19) of the engine (20), the valve lifting device (4)
being arranged to open a gas exchange valve (24, 25), the engine (20) further comprising
a starting arrangement having
- a pressure medium source (18),
- at least one starting valve (10) for introducing pressure medium into a cylinder
(19) of the engine (20),
- means (26) for connecting the pressure medium source (18) to the starting valves
(10), and
- a control valve (12) for each cylinder (19) that is provided with a starting valve
(10) for controlling the operation of the starting valve (10),
characterized in that each control valve (12) is arranged to be operated by a gas exchange cam (1) of the
respective cylinder (19).
2. An engine (20) according to claim 1, characterized in that each gas exchange cam (1) that operates a control valve (12) comprises a portion
(2c) that is arranged below the base circle (2a) of the cam (1) for operating the
control valve (12).
3. An engine (20) according to claim 1 or 2, characterized in that each control valve (12) is in flow communication with the pressure medium source
(18) and the respective starting valve (10) via a control air duct (21).
4. An engine (20) according to claim 3, characterized in that each control valve (12) is arranged to allow pressure medium flow to the starting
valve (10) for opening the starting valve (10) when the valve lifting device (4) is
engaged with the portion (2c) of the gas exchange cam (1) that is below the base circle
(2a) of the cam (1).
5. An engine (20) according to claim 4, characterized in that each control valve (12) comprises a valve member (13) that is movable by the valve
lifting device (4).
6. An engine (20) according to claim 5, characterized in that the valve lifting device (4) comprises a plunger (6) pushing the valve member (13)
towards the gas exchange cam (1) when the valve lifting device (4) is engaged with
the portion (2c) of the gas exchange cam (1) that is below the base circle (2a) of
the cam (1).
7. An engine (20) according to claim 5 or 6, characterized in that the valve member (13) is pushed towards the valve lifting device (4) by the pressure
of the pressure medium.
8. An engine (20) according to any of the preceding claims, characterized in that the gas exchange cam (1) is an intake cam.
9. An engine (20) according to claim 8, characterized in that each intake cam (1) comprises a second portion that is arranged below the base circle
(2a) of the cam (1) for controlling the operation of variable intake valve closing,
and the portion (2c) that is arranged below the base circle (2a) of the cam (1) is
arranged also below the said second portion.
10. An engine (20) according to any of claims 1-7, characterized in that the gas exchange cam (1) is an exhaust cam.
11. An engine (20) according to any of the preceding claims, characterized in that in a two-stroke engine at least three cylinders (19) of the engine (20) are provided
with a starting valve (10) and in a four-stroke engine (20) at least five cylinders
(19) of the engine (20) are provided with a starting valve (10).
12. An engine (20) according to claim 11, characterized in that all the cylinders (19) of the engine (20) are provided with a starting valve (10).
13. An engine (20) according to any of the preceding claims, characterized in that each control valve (12) comprises an inlet channel (14) for introducing pressure
medium into the control valve (12), an outlet channel (15) for introducing the pressure
medium to the starting valve (10) for opening the starting valve (10), and a drain
channel (16) for releasing the pressure medium out of the control valve (12) when
the control valve (12) is not actuated by the gas exchange cam (1).
14. An engine (20) according to any of the preceding claims, characterized in that the starting arrangement comprises a main starting valve (17) for initiating starting
of the engine (20).
1. Mehrzylinder-Kolbenmotor (20), umfassend wenigstens eine nockenbetätigte Ventilhebevorrichtung
(4) für jeden Zylinder (19) des Motors (20), wobei die Ventilhebevorrichtung (4) zum
Öffnen eines Gasaustauschventils (24, 25) eingerichtet ist, wobei der Motor (20) ferner
eine Anlasseinrichtung umfasst, die
- eine Druckmediumquelle (18),
- wenigstens ein Anlassventil (10) zur Einbringung des Druckmediums in einen Zylinder
(19) des Motors (20),
- Mittel (26) zum Anschluss der Druckmediumquelle (18) an die Anlassventile (10),
und
- ein Steuerventil (12) für jeden Zylinder (19), der mit einem Anlassventil (10) versehen
ist, um den Betrieb des Anlassventils (10) zu steuern,
aufweist,
dadurch gekennzeichnet, dass jedes Steuerventil (12) so eingerichtet ist, dass es durch eine Gasaustauschnocke
(1) des entsprechenden Zylinders (19) betätigt wird.
2. Motor (20) nach Anspruch 1, dadurch gekennzeichnet, dass jede Gasaustauschnocke (1), die ein Steuerventil (12) betätigt, einen Abschnitt (2c),
der unterhalb des Basiskreises (2a) der Nocke (1) angeordnet ist, umfasst, um das
Steuerventil (12) zu betätigen.
3. Motor (20) nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass jedes Steuerventil (12) über einen Steuerluftkanal (21) in einer Fluidverbindung
mit der Druckmediumquelle (18) und dem entsprechenden Anlassventil (10) steht.
4. Motor (20) nach Anspruch 3, dadurch gekennzeichnet, dass jedes Steuerventil (12) so eingerichtet ist, dass es einen Druckmediumfluss zu dem
Anlassventil (10) gestattet, um das Anlassventil (10) zu öffnen, wenn die Ventilhebevorrichtung
(4) mit dem Abschnitt (2c) der Gasaustauschnocke (1), der sich unterhalb des Basiskreises
(2a) der Nocke (1) befindet, in Eingriff gebracht wird.
5. Motor (20) nach Anspruch 4, dadurch gekennzeichnet, dass jedes Steuerventil (12) ein Ventilelement (13) umfasst, das durch die Ventilhebevorrichtung
(4) bewegt werden kann.
6. Motor (20) nach Anspruch 5, dadurch gekennzeichnet, dass die Ventilhebevorrichtung (4) einen Kolben (6) umfasst, der das Ventilelement (13)
zu der Gasaustauschnocke (1) schiebt, wenn die Ventilhebevorrichtung (4) mit dem Abschnitt
(2c) der Gasaustauschnocke (1), der sich unterhalb des Basiskreises (2a) der Nocke
(1) befindet, in Eingriff gebracht wird.
7. Motor (20) nach Anspruch 5 oder 6, dadurch gekennzeichnet, dass das Ventilelement (13) durch den Druck des Druckmediums zu der Ventilhebevorrichtung
(4) geschoben wird.
8. Motor (20) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Gasaustauschnocke (1) eine Ansaugnocke ist.
9. Motor (20) nach Anspruch 8, dadurch gekennzeichnet, dass jede Ansaugnocke (1) einen zweiten Abschnitt umfasst, der unterhalb des Basiskreises
(2a) der Nocke (1) angeordnet ist, um den Betrieb des Schließens des variablen Ansaugventils
zu steuern, und der Abschnitt (2c), der unterhalb dem Basiskreises (2a) der Nocke
(1) angeordnet ist, auch unterhalb dieses zweiten Abschnitts angeordnet ist.
10. Motor (20) nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass die Gasaustauschnocke (1) eine Auslassnocke ist.
11. Motor (20) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass in einem Zweitaktmotor wenigstens drei Zylinder (19) des Motors (20) mit einem Anlassventil
(10) versehen sind, und in einem Viertaktmotor (20) wenigstens fünf Zylinder (19)
des Motors (20) mit einem Anlassventil (10) versehen sind.
12. Motor (20) nach Anspruch 11, dadurch gekennzeichnet, dass alle Zylinder (19) des Motors (20) mit einem Anlassventil (10) versehen sind.
13. Motor (20) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass jedes Steuerventil (12) einen Einlasskanal (14) zur Einbringung des Druckmediums
in das Steuerventil (12), einen Auslasskanal (15) zu Einbringung des Druckmediums
in das Anlassventil (10), um das Anlassventil (10) zu öffnen, und einen Ablasskanal
(16) zum Abgeben des Druckmediums aus dem Steuerventil (12), wenn das Steuerventil
(12) nicht durch die Gasaustauschnocke (1) betätigt wird, umfasst.
14. Motor (20) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Anlassanordnung ein Hauptanlassventil (17) umfasst, um das Anlassen des Motors
(20) zu beginnen.
1. Moteur à pistons multi-cylindres (20) comprenant au moins un dispositif de levage
de soupape actionné par cames (4) pour chaque cylindre (19) du moteur (20), le dispositif
de levage de soupape (4) étant agencé pour ouvrir une soupape d'échange gazeux (24,
25), le moteur (20) comprenant en outre un agencement de démarrage présentant
- une source de fluide sous pression (18),
- au moins une soupape de démarrage (10) pour introduire du fluide sous pression dans
un cylindre (19) du moteur (20),
- un moyen (26) pour relier la source de fluide sous pression (18) aux soupapes de
démarrage (10), et
- une soupape de commande (12) pour chaque cylindre (19) qui est dotée d'une soupape
de démarrage (10) pour commander le fonctionnement de la soupape de démarrage (10),
caractérisé en ce que chaque soupape de commande (12) est agencée pour être actionnée par une came d'échange
gazeux (1) du cylindre respectif (19).
2. Moteur (20) selon la revendication 1, caractérisé en ce que chaque came d'échange gazeux (1) qui fait fonctionner une soupape de commande (12)
comprend une partie (2c) qui est agencée sous le cercle de base (2a) de la came (1)
pour faire fonctionner la soupape de commande (12).
3. Moteur (20) selon la revendication 1 ou 2, caractérisé en ce que chaque soupape de commande (12) est en communication fluidique avec la source de
fluide sous pression (18) et la soupape de démarrage respective (10) via un conduit
d'air de commande (21).
4. Moteur (20) selon la revendication 3, caractérisé en ce que chaque soupape de commande (12) est agencée pour permettre un écoulement du fluide
sous pression vers la soupape de démarrage (10) pour ouvrir la soupape de démarrage
(10) lorsque le dispositif de levage de soupape (4) est engagé avec la partie (2c)
de la came d'échange gazeux (1) qui est sous le cercle de base (2a) de la came (1).
5. Moteur (20) selon la revendication 4, caractérisé en ce que chaque soupape de commande (12) comprend un élément de soupape (13) qui peut être
déplacé par le dispositif de levage de soupape (4).
6. Moteur (20) selon la revendication 5, caractérisé en ce que le dispositif de levage de soupape (4) comprend un plongeur (6) poussant l'élément
de soupape (13) en direction de la came d'échange gazeux (1) lorsque le dispositif
de levage de soupape (4) est engagé avec la partie (2c) de la came d'échange gazeux
(1) qui est sous le cercle de base (2a) de la came (1).
7. Moteur (20) selon la revendication 5 ou 6, caractérisé en ce que l'élément de soupape (13) est poussé en direction du dispositif de levage de soupape
(4) par la pression du fluide sous pression.
8. Moteur (20) selon l'une quelconque des revendications précédentes, caractérisé en ce que la came d'échange gazeux (1) est une came d'admission.
9. Moteur (20) selon la revendication 8, caractérisé en ce que chaque came d'admission (1) comprend une seconde partie qui est agencée sous le cercle
de base (2a) de la came (1) pour commander le fonctionnement de la fermeture variable
de la soupape d'admission, et la partie (2c) qui est agencée sous le cercle de base
(2a) de la came (1) est également agencée en-dessous de la seconde partie.
10. Moteur (20) selon l'une quelconque des revendications 1 - 7, caractérisé en ce que la came d'échange gazeux (1) est une came d'échappement.
11. Moteur (20) selon l'une quelconque des revendications précédentes, caractérisé en ce que dans un moteur à deux temps, au moins trois cylindres (19) du moteur (20) sont dotés
d'une soupape de démarrage (10), et dans un moteur à quatre temps (20), au moins cinq
cylindres (19) du moteur (20) sont dotés d'une soupape de démarrage (10).
12. Moteur (20) selon la revendication 11, caractérisé en ce que tous les cylindres (19) du moteur (20) sont dotés d'une soupape de démarrage (10).
13. Moteur (20) selon l'une quelconque des revendications précédentes, caractérisé en ce que chaque soupape de commande (12) comprend un canal d'entrée (14) pour introduire du
fluide sous pression dans la soupape de commande (12), un canal de sortie (15) pour
introduire le fluide sous pression vers la soupape de démarrage (10) pour ouvrir la
soupape de démarrage (10), et un canal d'évacuation (16) pour libérer le fluide sous
pression hors de la soupape de commande (12) lorsque la soupape de commande (12) n'est
pas déclenchée par la came d'échange gazeux (1).
14. Moteur (20) selon l'une quelconque des revendications précédentes, caractérisé en ce que l'agencement de démarrage comprend une soupape de démarrage principale (17) pour
déclencher le démarrage du moteur (20).
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description