JPH0310370Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention is an internal combustion engine that prevents the generation of metallic noise due to self-ignition immediately after restart by controlling combustion during restart within a short time after the engine has stopped. relating to an exhaust gas recirculation device.

[Technical background of the invention]

In an internal combustion engine, for example, a spark ignition four-stroke gasoline engine, a reciprocating piston draws a mixture of fuel and air into a combustion chamber under negative pressure. The air-fuel mixture sucked into the combustion chamber is compressed at a constant compression ratio, and then ignited by a spark plug and combusted. The larger the compression ratio, the more kinetic energy can be extracted, but if it is too large, there is a problem that the fuel will self-ignite. Therefore, the compression ratio is set to a predetermined value depending on the properties of the fuel and the engine.

[Problems with background technology]

By the way, if the internal combustion engine is restarted within a short time after it has been stopped while the engine is still sufficiently warm, the engine may generate a metallic sound. This is due to self-ignition of the air-fuel mixture. In other words, if the piston stops near the bottom dead center of the intake stroke when the internal combustion engine stops,
Since the combustion chamber provided with this piston is under negative pressure when the engine is in operation, the air-fuel mixture in the intake passage is sucked in after the engine is stopped, and the pressure rises to atmospheric pressure. The air-fuel mixture sucked into the combustion chamber gradually leaks out of the combustion chamber over time after the internal combustion engine stops.
Within a short time after the stoppage, for example within 10 minutes after the stoppage, the gas remains in the combustion chamber without leaking sufficiently. In this way, when the internal combustion engine is stopped, the air-fuel mixture is sucked into the combustion chamber where the piston has stopped near the bottom dead center of the intake stroke, and the air-fuel mixture remains in the combustion chamber without leaking out. When an internal combustion engine is restarted within a short period of time after it has stopped, the combustion chamber that has sucked in the air-fuel mixture enters the compression stroke immediately after the restart, and the pressure increases compared to the steady state, which, together with a sufficiently warm engine temperature, causes the combustion chamber to enter the compression stroke. It gets hot. As a result, the air-fuel mixture self-ignites, resulting in a sudden pressure increase due to the explosion of the air-fuel mixture, which forces the cylinder wall to vibrate, resulting in the inconvenience of producing a metallic sound.

[Purpose of invention]

The object of this invention is to realize an exhaust gas recirculation device for an internal combustion engine that controls combustion to prevent the generation of metallic noise due to self-ignition when restarting the engine within a short time after the engine is stopped.

[Structure of the idea]

In order to achieve this purpose, this invention provides a passage that communicates an exhaust passage and an intake passage in order to introduce exhaust gas into the combustion chamber of an internal combustion engine, and the passage is provided with a passage that connects the exhaust passage and the intake passage in order from the side closest to the exhaust passage. When the internal combustion engine is stopped with the stop valve, the exhaust gas reservoir, and the ignition switch turned off, the exhaust gas concentration of the air-fuel mixture drawn into the combustion chamber when the piston stops near the bottom dead center of the intake stroke is calculated. In order to increase the temperature, an ignition switch that is turned on when the internal combustion engine is operating is closed to block the flow of exhaust gas and accumulate exhaust gas in the reservoir, and an ignition switch that is turned off when the internal combustion engine is stopped. The present invention is characterized in that a valve mechanism is provided which allows the exhaust gas stored in the storage section to flow into the intake passage when opened.

[Example of idea]

Next, an embodiment of this invention will be described in detail based on the drawings. The figure is a sectional view of an internal combustion engine showing an embodiment of this invention. In the figure, 2 is an internal combustion engine, 4
1 is an intake passage, 6 is an exhaust passage, 8 is a combustion chamber, and 10 is a piston. The intake valve 12 and the exhaust valve 14 are
It opens and closes in conjunction with the reciprocating movement of the piston 10. The air-fuel mixture sucked into the combustion chamber 8 from the intake passage 4 through the intake port 16 is ignited by a spark plug (not shown) and combusts. The exhaust gas after combustion reaches the exhaust passage 6 via the exhaust port 18 and is discharged to the outside of the engine.

The exhaust passage 6 and the intake passage 4 communicate through an introduction passage 20 for introducing exhaust gas into the combustion chamber 8. For this reason, it is desirable that the opening 22 of the introduction passage 20 on the intake passage 4 side be provided close to the intake port 16. This introduction passage 20 includes the exhaust passage 6
Reed valve 30, which is a check valve, is sequentially installed from the side closest to
When the internal combustion engine 2 is stopped with the tank 28, which is the exhaust gas storage part, and the main switch 26, which is the ignition switch, turned off, the piston 10
is closed by the main switch 26, which is an ignition switch, which is turned on when the internal combustion engine 2 is operating, in order to increase the concentration of exhaust gas in the air-fuel mixture taken into the combustion chamber 8, which has stopped near the bottom dead center of the intake stroke. The main switch 26, which is an ignition switch, is opened by the main switch 26, which is an ignition switch, and turns off when the internal combustion engine 2 is stopped, thereby blocking the flow of exhaust gas and storing the exhaust gas in the tank 28, which is the storage part. A solenoid valve 24 serving as a valve mechanism for causing accumulated exhaust gas to flow into the intake passage 4 is provided.

That is, when the internal combustion engine 2 is stopped with the main switch 26 in the OFF state, the internal combustion The main switch 2 is closed by the main switch 26, which is turned on when the engine 2 is in operation, to prevent the flow of exhaust gas, and is turned off when the engine 2 is stopped.
An electromagnetic valve 24, which is a valve mechanism that is opened by 6 to allow the intake air to flow into the intake passage 4, is provided in the introduction passage 20.
The solenoid valve 24 is turned on and off in conjunction with the opening and closing of a main switch 26, which is an ignition switch for the internal combustion engine 4, for example. That is, when the main switch 26 is on when the internal combustion engine 2 is operating, the solenoid valve 24 is turned on and closed. When the main switch 26 is in the off state when the engine is stopped, the solenoid valve 24 is turned off and opened to allow a large amount of exhaust gas to flow into the intake passage 4. As a result, main switch 2
When the internal combustion engine 4 is stopped with the piston 6 in the off state, and the piston 10 stops near the bottom dead center of the intake stroke, the concentration of exhaust gas mixed in the air-fuel mixture taken into the combustion chamber 8 in which the piston 10 is installed is calculated. enhance

In the introduction passage 20 on the side of the exhaust passage 6 from the electromagnetic valve 24, a tank 2 serving as a reservoir for storing exhaust gas is provided.
There are 8. Inside the tank 28, an intake passage 4 is provided.
A reed valve 30 is built in as a check valve that allows exhaust gas to flow only to the side. This reed valve 3
0, exhaust gas is stored in the tank 28 during engine operation.

The effect of this idea will be explained.

When the internal combustion engine 2 is operating, the main switch 26
is in the on state, solenoid valve 24
is turned on and is operated to close, thereby closing the introduction passage 20. At this time, high-pressure exhaust gas generated by combustion pushes open the reed valve 30, flows into the tank 28, and is stored therein.

When the main switch 26 is turned off to stop the internal combustion engine 2, the solenoid valve 24 is turned off and opened, thereby opening the introduction passage 20. When the electromagnetic valve 24 is opened, a large amount of exhaust gas flows into the intake passage 4 from the tank 28, where exhaust gas is stored and has a high pressure, since the intake passage 4 is under negative pressure during engine operation. On the other hand, when the internal combustion engine 2 is stopped with the main switch 26 in the OFF state, if the piston 10 stops near the bottom dead center of the intake stroke, the intake valve 12 will stop in the open state. In this way, the inside of the combustion chamber 8 where the piston 10 has stopped near the bottom dead center of the intake stroke is in a negative pressure state during the intake stroke. You will have to inhale it.

In this way, when the internal combustion engine 2 is stopped with the main switch 26 in the OFF state, and the piston 10 stops near the bottom dead center of the intake stroke, only the air-fuel mixture remains in the combustion chamber 8 in which the piston 10 is installed. Since a large amount of inert exhaust gas is taken in instead of the combustion chamber 8, the concentration of exhaust gas mixed in the air-fuel mixture taken into the combustion chamber 8 can be increased. Therefore, even if the internal combustion engine 2 is restarted within a short time after it is stopped and the engine is sufficiently warm, no metallic noise will be generated due to self-ignition.

That is, when the internal combustion engine 2 is stopped with the main switch 26 in the OFF state, the solenoid valve 24 is opened by the main switch 26 in the OFF state, and the exhaust gas stored in the tank 28 flows into the intake passage 4. At this time, when the piston 10 stops near the bottom dead center of the intake stroke, the combustion chamber 12 in which the piston 10 is installed is in a negative pressure state during the intake stroke, so there is no air-fuel mixture and exhaust gas in the combustion chamber 8. When inhaled, the pressure becomes atmospheric. In this way, the main switch 26
The combustion chamber 1 in which the piston 10 has stopped near the bottom dead center of the intake stroke when the internal combustion engine 2 is stopped with the engine in the off state
An internal combustion engine 2 in which an air-fuel mixture and exhaust gas are sucked into the combustion chamber 12, and the air-fuel mixture and exhaust gas remain in the combustion chamber 12 without sufficiently leaking out.
When the engine is restarted within a short period of time when it is sufficiently warm after stopping, even if the combustion chamber 8 that sucks the air-fuel mixture and exhaust gas becomes higher in pressure than in the steady state during the compression process immediately after the restart, Since the exhaust gas is mixed into the combustion chamber 8 and the mixture is diluted by increasing the concentration of the exhaust gas in the mixture, self-ignition will not occur. Alternatively, it can be misfired. Also,
Even if it self-ignites, it can burn slowly.

Therefore, rapid combustion during restart of the internal combustion engine 2 within a short time after stopping is controlled, and generation of metallic noise due to a sudden pressure increase can be prevented.

Note that this metallic sound occurs only during the compression process immediately after the internal combustion engine 2 is restarted within a short time after it has stopped, and from the next time onwards, the intake stroke will occur, so the pressure inside the combustion chamber will become negative, and the pressure will become low enough to cause self-ignition. It won't happen because it won't rise.

In addition, the solenoid valve 24, which is a valve mechanism that opens when the internal combustion engine 2 is running and closes when it stops, is controlled to open and close not only by the main switch 26 but also by the on/off of the kill switch, the presence or absence of pulses from the ignition pulse relay, etc. can do.

[Effect of idea]

As described above, according to this invention, when the internal combustion engine is stopped with the ignition switch turned off, a large amount of exhaust gas flows into the intake passage, so that when the internal combustion engine is stopped, the piston stops near the bottom dead center of the intake stroke. In this case, a large amount of exhaust gas is drawn into the combustion chamber together with the air-fuel mixture. Therefore, when the internal combustion engine is stopped, the exhaust gas concentration of the air-fuel mixture sucked into the combustion chamber when the piston stops near the bottom dead center of the intake stroke can be increased, and the mixture with the increased exhaust gas concentration can be When the internal combustion engine is restarted within a short period of time after the internal combustion engine has stopped, when the air-fuel mixture and exhaust gas in the combustion chamber are still in the state without leaking out, the air-fuel mixture and the air-fuel mixture after the engine has stopped are Even if the combustion chamber, which has been brought to atmospheric pressure by inhaling exhaust gas, reaches a higher pressure than normal during the compression process immediately after restarting, the mixture of exhaust gas increases the concentration of the exhaust gas and thins the air-fuel mixture. This prevents self-ignition or causes misfire, and even if self-ignition occurs, it can be burned slowly. By controlling combustion in this way,
When the engine is restarted within a short time after stopping, a sudden pressure increase is not caused, and metallic noise can be prevented from occurring.

[Brief explanation of the drawing]

The figure is a sectional view of an internal combustion engine showing an embodiment of this invention. In the figure, 4 is an intake passage, 6 is an exhaust passage, and 8
is the combustion chamber, 10 is the piston, 16 is the intake port, 20
24 is an introduction passage, 24 is a solenoid valve, 26 is a main switch, 28 is a tank, and 30 is a reed valve.

Claims (1)

[Scope of utility model registration request] In order to introduce exhaust gas into the combustion chamber of an internal combustion engine, a passage is provided that communicates an exhaust passage with an intake passage, and a check valve, an exhaust gas reservoir, and an ignition valve are sequentially installed in the passage from the side closest to the exhaust passage. When the internal combustion engine is stopped with the engine switch turned off, the piston stops near the bottom dead center of the intake stroke.In order to increase the concentration of exhaust gas mixed in the air-fuel mixture sucked into the combustion chamber, the switch is turned on when the internal combustion engine is running. The exhaust gas is closed by an ignition switch that prevents the flow of exhaust gas and is stored in the reservoir, and is turned off when the internal combustion engine is stopped. An exhaust gas recirculation device for an internal combustion engine, comprising a valve mechanism for causing exhaust gas to flow into the intake passage.