JP2005282410A - Stop control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve startability of an internal combustion engine while restraining evaporated fuel from leaking outside at the stop of the internal combustion engine. <P>SOLUTION: This stop control device for the internal combustion engine is provided with a shielding valve provided in an exhaust pipe of the internal combustion engine to open/close the inside of the pipe, and an EGR valve provided in an EGR passage communicating the intake side with the exhaust side of the internal combustion engine to open/close the inside of a pipe. A shielding valve control program 114 for putting the shielding valve in the closed state after the stop of the internal combustion engine, and an EGR valve control program 115 for putting the EGR valve in the open state after the shielding valve is put in the closed state, are stored in an ROM 102 of an ECU 100. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine stop control device.

  Generally, an internal combustion engine is used as a prime mover of an automobile vehicle, and a gasoline engine, a diesel engine, or the like is mounted. Further, an engine composed of an internal combustion engine is mounted on a ship, a railway vehicle, etc., and an internal combustion engine is also used for a prime mover such as an industrial machine. The internal combustion engine is connected to an intake pipe that sucks fresh air from outside air and an exhaust pipe that discharges exhaust gas after combustion of the air-fuel mixture.

  In such an internal combustion engine, when the operation is stopped, the inert gas may flow backward from the exhaust pipe and flow into the combustion chamber. That is, taking an automobile vehicle as an example, the exhaust pipe as an exhaust pipe and the inert gas inside the muffler flow backward to the combustion chamber side due to the wind pressure at the tail part of the muffler.

At this time, if the intake valve and the exhaust valve of the internal combustion engine are in an overlapped state, an inert gas enters the combustion chamber and the intake pipe, resulting in a problem that the startability of the internal combustion engine deteriorates. In order to solve this problem, there has been proposed an internal combustion engine stop control device that controls the camshaft of each valve when the internal combustion engine is stopped so that the intake valve and the exhaust valve do not overlap each other (for example, Patent Documents). 1).
JP 2002-21593 A

However, in reality, it is extremely difficult to control the camshaft so as to predict the overlap state and avoid it. Here, if a one-way clutch or the like that brakes the camshaft is added so as to ensure a more non-overlapping state, the mechanism near the output shaft of the internal combustion engine becomes complicated and reliability durability decreases, This is also not realistic. Therefore, the current situation is that the startability of the internal combustion engine has not yet been improved.
In addition to the internal combustion engine stop control device, there is a problem in that evaporated fuel leaks to the outside after the internal combustion engine is stopped from an injector connected to the intake side.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the leakage of evaporated fuel to the outside when the internal combustion engine is stopped and to improve the startability of the internal combustion engine. An internal combustion engine stop control device capable of performing

  In order to achieve the above object, according to the first aspect of the present invention, a shielding valve provided in an exhaust pipe connected to the internal combustion engine for opening and closing the inside of the pipe, and a communication pipe communicating the intake side and the exhaust side of the internal combustion engine. A communication valve provided to open and close the pipe, shielding valve control means for closing the shielding valve after operation of the internal combustion engine, and after the shielding valve is closed by the shielding valve control means, And a communication valve control means for opening the communication valve.

According to the first aspect of the present invention, after the operation of the internal combustion engine is stopped, the exhaust pipe is closed by the shielding valve, so that the inert gas in the exhaust pipe flows back to the internal combustion engine side by the wind pressure near the outlet of the exhaust pipe. There is nothing.
Further, the inert gas in the exhaust pipe is cooled and contracted after the internal combustion engine is stopped. As a result, a negative pressure is generated on the intake side of the internal combustion engine, and fresh air is supplied to the internal combustion engine from the intake pipe. Here, when the intake valve and the exhaust valve of the internal combustion engine are stopped in an overlapped state, the intake side and the exhaust side of the internal combustion engine communicate with each other through the valves, so that the inert gas in the combustion chamber is exhausted. Can be inhaled to the side. Since fresh air is sucked into the combustion chamber, the next start of the internal combustion engine can be improved.
Regardless of whether the intake valve and the exhaust valve are in an overlapped state, the evaporated fuel leaking from the fuel supply device on the intake side after the internal combustion engine is stopped is sucked into the exhaust pipe side. Therefore, the evaporated fuel does not leak to the outside, and the surrounding environment and safety can be greatly improved. Further, since the evaporated fuel does not remain in the intake pipe, the air-fuel ratio at the next start-up of the internal combustion engine becomes appropriate, and good startability can be obtained.

  According to a second aspect of the present invention, in the internal combustion engine stop control device according to the first aspect, when it is determined that the intake valve and the exhaust valve of the internal combustion engine are stopped in an overlapping state, the communication valve control means An overlap control means for prohibiting the operation and closing the communication valve is provided.

According to the second aspect of the present invention, in addition to the operation of the first aspect, the communication valve is closed when it is determined that the intake valve and the exhaust valve of the internal combustion engine are stopped in an overlapped state. Here, the opening degree of the intake valve and the exhaust valve that the overlap control means determines to be in the overlap state can be arbitrarily determined. That is, even if the intake valve and the exhaust valve are in an overlapped state, if the opening of at least one of the valves is small and it is difficult to pass the gas through the combustion chamber, it is determined that the valve is not in the overlapped state. Also good.
When the internal combustion engine stops in the overlap state and the inert gas in the exhaust pipe contracts, fresh air is supplied to the combustion chamber. At this time, since the communication valve is closed, all the air from the outside is introduced into the combustion chamber without passing through the communication pipe, so that the inert gas can be efficiently sucked into the exhaust side.

  According to a third aspect of the present invention, in the internal combustion engine stop control device according to the first or second aspect, the shielding valve control means is configured so that the internal combustion engine is stopped based on an operating speed before the internal combustion engine is stopped. The time until the shielding valve is closed is determined.

  According to the third aspect of the invention, in addition to the action of the first or second aspect, the shielding valve can be closed according to the timing at which the exhaust pressure generated even after the internal combustion engine stops. Here, since the exhaust pressure generated after the internal combustion engine stops depends on the operating speed of the internal combustion engine before the stop, the shielding valve can be closed at an appropriate timing. Accordingly, the shielding valve does not close even though exhaust pressure is generated, and the load applied to each part of the exhaust system can be reduced, and the reliability durability of each part can be improved.

  According to a fourth aspect of the present invention, in the internal combustion engine stop control device according to any one of the first to third aspects, after the shielding valve is closed by the shielding valve control means, the intake of the internal combustion engine Throttle valve control means for increasing the opening degree of the throttle valve arranged in the pipe is provided.

  According to the fourth aspect of the invention, in addition to the operation of any one of the first to third aspects, since the opening of the throttle valve increases after the internal combustion engine is stopped, the flow of the gas passing through the intake pipe Resistance decreases. Therefore, the outside air can be efficiently introduced to the internal combustion engine side when the inert gas contracts.

  According to a fifth aspect of the invention, in the internal combustion engine stop control device according to any one of the first to fourth aspects, when the shielding valve is in a closed state, the upstream side and the downstream side have a predetermined pressure or more. In this case, an opening mechanism that allows fluid to flow from upstream to downstream is provided.

  According to the fifth aspect of the invention, in addition to the action of any one of the first to fourth aspects, when the upstream side and the downstream side of the shielding valve have a difference of a predetermined pressure or more, the opening mechanism of the shielding valve is In operation, the flow of exhaust gas from the upstream side to the downstream side is allowed. Thereby, the flow of the exhaust gas is not hindered by the shielding valve.

  Thus, according to the present invention, leakage of evaporated fuel to the outside when the internal combustion engine is stopped can be suppressed, and the startability of the internal combustion engine can be improved.

  1 to 6 show an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of an engine control system of an automobile vehicle, FIG. 2 is an explanatory diagram of an exhaust system of the automobile vehicle, and FIG. 3 is an explanatory diagram of a shielding valve. 4 is a schematic block diagram of the engine control system, FIG. 5 is a set time table, and FIG. 6 is a flowchart of the control system when the engine is stopped. Note that FIG. 2 is merely an explanatory diagram, and the EGR passage and the like are omitted. Further, FIG. 3 is only an explanatory diagram, and the exhaust pipe hatching and the like are omitted.

  As shown in FIG. 1, the internal combustion engine of the present embodiment is an engine 1 mounted on an automobile vehicle. The engine 1 has a spark plug 6 facing a combustion chamber 5 formed by a cylinder head 2, a cylinder block 3 and a piston 4. The ignition plug 6 is connected to the secondary side of the ignition coil 7, and an igniter 8 is connected to the primary side of the ignition coil 7. In this embodiment, the engine 1 is an in-line three-cylinder type and is supercharged by a mechanical supercharger system.

  The cylinder block 3 is formed with an intake port 3a and an exhaust port 3b. An intake manifold 9 is connected to the intake port 3a, and an exhaust pipe 10 is connected to the exhaust port 3b.

  As shown in FIG. 1, an injector 11 that injects fuel is connected to the intake manifold 9. Fuel is supplied to the injector 11 from the fuel tank 12 through the fuel supply passage 13. The fuel is pressure-adjusted by the fuel pressure regulator 14 and then injected into the intake manifold 9.

  An intake duct 15 is connected to the upstream side of the intake manifold 9. In the present embodiment, the intake manifold 9 and the intake duct 15 form an intake pipe. An air cleaner 16, an intake air amount sensor 17, a check valve 18, and a throttle valve 19 are interposed in this intake duct 15 in order from the upstream side. The throttle valve 19 opens and closes in conjunction with the amount of depression of the accelerator pedal 20. In the present embodiment, the amount of depression of the accelerator pedal 20 is monitored by the accelerator opening sensor 20a, and the throttle valve 19 is controlled based on a signal transmitted from the accelerator opening sensor 20a.

  As shown in FIG. 2, the exhaust pipe 10 has a catalytic converter 21 made of a metal catalyst for purifying CO and HC, and is connected to a muffler 22. Further, as shown in FIG. 1, an EGR passage 23 serving as a communication pipe extends from the upstream side of the muffler 22, and exhaust gas is recirculated through the EGR passage 23 to perform NOx reduction processing. The EGR passage 23 has a pipe area that can secure a sufficient gas flow rate, and communicates with the downstream side of the check valve 18 of the intake duct 15 via an EGR control valve 24 as a communication valve. Backflow of exhaust gas during control is prevented, and errors in the intake air amount sensor 17 are prevented.

  As shown in FIG. 2, a shielding valve 25 that opens and closes the inside of the pipe is provided at a connection portion between the exhaust pipe 10 and the muffler 22. As shown in FIG. 3B, the shielding valve 25 includes a disk-shaped plate member 25a, a shaft member 25b fixed to the plate member 25a, and a drive motor 25c that rotationally drives the shaft member 25b. Have. The shielding valve 25 is connected to the ECU 100 and opens and closes the inside of the pipe based on a signal transmitted from the ECU 100. In consideration of heat resistance, the material of the shaft member 25b is preferably Teflon (registered trademark), and more preferably, the shaft member 25b is water-cooled.

  Further, as shown in FIG. 3A, when the shielding valve 25 is in a closed state, if the upstream side and the downstream side have a difference equal to or greater than a predetermined pressure, the shielding valve 25 is opened to allow fluid flow from upstream to downstream. It has a mechanism 26. The opening mechanism 26 includes a safety hole 26a formed in the plate member 25a, a lid member 26b that closes the safety hole 26a, and a spring member 26c that biases the lid member 26b in the closing direction. That is, in this embodiment, when the difference between the upstream side and the downstream side becomes a predetermined pressure or more and the pressure applied to the lid member 26b becomes larger than the biasing force of the spring member 26c, the lid member 26b moves and the safety hole is moved. Distribution of exhaust gas is allowed through 26a. In the present embodiment, the urging force of the spring member 26 c is set in accordance with the exhaust gas pressure during normal operation of the engine 1, and does not hinder the operation of the engine 1.

  As shown in FIG. 1, the EGR control valve 24 includes a plate-like slide valve 24a interposed in a joining portion where the EGR passage 23 joins the intake duct 15, and a solenoid 24b for moving the slide valve 24a forward and backward. The slide valve 24a is urged in the closing direction by the spring 24c. The solenoid 24b of the EGR control valve 24 is connected to the ECU 100 and opens the slide valve 24a based on a signal transmitted from the ECU 100.

  The ECU 100 controls the sensors and actuators including the EGR control valve 24 and the shielding valve 25. As shown in FIG. 4, the ECU 100 includes a microcomputer in which a CPU 101, a ROM 102, a RAM 103, a backup RAM 104, an I / O interface 105, and a timer 108 are connected to each other via a bus line 106. The ECU 100 also includes a constant voltage circuit (not shown) that supplies a predetermined stabilized power source to each unit, a drive circuit 107 that drives each actuator, and the like.

To the input port of the I / O interface 105, an intake air amount sensor 17, an accelerator opening sensor 20a, a crank angle sensor 27, and the like are connected.
Further, the igniter 8 is connected to the output port of the I / O interface 105, and the drive motor 25c of the shielding valve 25, the solenoid 24b of the EGR control valve 24, and the like are connected.

  The ROM 102 stores various control programs, control fixed data, and the like. The RAM 103 stores data obtained by processing signals from sensors, switches, and the like, data obtained by arithmetic processing by the CPU 101, and the like. Further, power is supplied to the backup RAM 104 regardless of the ignition switch 28, and the stored contents are not erased even if the operation of the engine 1 is stopped.

  As shown in FIG. 4, the ROM 102 includes an air-fuel ratio control program 110 for adjusting the fuel injection amount of the injector 11, an ignition timing control program 111 for controlling the spark plug 6 by the igniter 8, and when the engine 1 is in the EGR region. Each control program such as an EGR control program 112 for driving the solenoid 24b of the EGR control valve 24 is stored.

  The ROM 102 stores an engine stop control program 113. The engine stop control program 113 includes a shielding valve control program 114, an EGR valve control program 115, and a throttle valve control program 116. The shielding valve control program 114 is a program for closing the shielding valve 25 after the engine 1 is stopped. The EGR valve control program 115 is a program for opening the EGR valve 24 after the shielding valve 25 is closed. The throttle valve control program 116 is a program for increasing the opening degree of the throttle valve 19 after the shielding valve 25 is closed. That is, the ECU 100 serves as a shielding valve control means, a communication valve control means, and a throttle valve control means.

  In the present embodiment, it is determined that the engine 1 has stopped when the ignition switch 28 is turned off. Further, the time from when the engine 1 is stopped to when the shielding valve 25 is closed is determined according to the rotational speed before the engine 1 is stopped. Specifically, the engine 1 determines from the signal of the accelerator opening sensor 20a whether or not the amount of depression of the accelerator pedal 20 is in an idle state (idle switch ON state), and is set according to the idle state. Based on the time table 120, the set time in the timer 108 is determined. As shown in FIG. 5A, when the amount of depression of the accelerator pedal 20 is not in the idle state, the time until the exhaust pressure after the engine 1 stops is relatively long. The set time is longer than that in the idle state.

Further, as shown in FIG. 4, when the engine stop control program 113 determines that the intake valve and the exhaust valve of the engine 1 are stopped in an overlapped state, the operation by the EGR valve control program 115 is prohibited and EGR control is performed. An overlap control program 117 for closing the valve 24 is provided. That is, in this embodiment, the ECU 100 serves as an overlap control unit. Here, the opening degree of the intake valve and the exhaust valve determined to be in the overlap state can be arbitrarily determined. That is, even if the intake valve and the exhaust valve are in the overlap state, if the opening of at least one of the valves is small and it is difficult to pass the gas through the combustion chamber 5, it is determined that the valve is not in the overlap state. It may be. In this embodiment, since the slide valve 24a of the EGR control valve 24 is urged in the closing direction by the spring 24c, the EGR control valve 24 can be kept closed only by prohibiting the energization of the solenoid 24b. it can.
As described above, the internal combustion engine stop control device according to the present embodiment includes the shielding valve 25, the EGR valve 24 as a communication valve, the shielding valve control means, the communication valve control means, the overlap control means, and the throttle valve control means. ECU100.

  The operation of the ECU 100 of the internal combustion engine stop control device configured as described above will be described with reference to the flowchart shown in FIG. In this flowchart, the operating state of the engine 1 is the initial state.

  First, the ECU 100 determines whether or not the ignition switch 28 is in an OFF state (step S1). If the ON state continues, the ECU 100 returns to step S1 to enter a standby state. If the ignition switch 28 is in the OFF state in step S1, the timer 108 is set with reference to the set time table 120 described above (step S2).

  Thereafter, it is determined whether or not the engine 1 has completely stopped (step S3). If the engine 1 has not stopped, the process returns to step S3 to enter a standby state. If it is determined in step S3 that the engine 1 has stopped, the timer 108 is started (step S4). Then, the standby state is continued until the set time of the timer 108 elapses (step S5: No), and when the set time of the timer 108 elapses (step S5: Yes), the drive motor 25c is controlled to close the shielding valve 25. (Step S6).

  Thereafter, it is determined whether or not the stop state of the engine 1 is the above-described overlap state (step S7). If it is determined that the engine 1 is in the non-overlap state, the solenoid 24b is controlled to open the EGR valve 24 ( Step S8). If it is determined in step S7 that the state is the overlap state, the EGR valve 24 is kept closed without driving the solenoid 24b (step S9). After step S8 and step S9, the opening degree of the throttle valve 19 is increased (step S10), and the operation is terminated. Although not particularly shown, when the engine 1 is started again, the throttle valve 19 is returned to the normal state, the EGR valve 24 is closed, and the shielding valve 25 is controlled to be open. .

  Thus, according to the internal combustion engine stop control device of the present embodiment, the exhaust pipe composed of the exhaust pipe 10 and the muffler 22 is closed by the shielding valve 25 after the engine 1 is stopped, so that the wind pressure near the outlet of the muffler 22 is blocked. Thus, the inert gas in the exhaust pipe does not flow backward to the engine 1 side.

  Further, the inert gas in the exhaust pipe is cooled and contracted after the engine 1 is stopped. As a result, negative pressure is generated on the intake side of the engine 1, and fresh air is supplied to the engine 1 from the intake duct 15. Here, when the intake valve and the exhaust valve of the engine 1 are stopped in an overlapped state, the intake side and the exhaust side of the engine 1 communicate with each other through the respective valves. Can be sucked into the exhaust side. And since fresh air is inhaled in the combustion chamber 5, the next start-up of the engine 1 can be made favorable.

  In particular, in the present embodiment, when it is determined that the intake valve and the exhaust valve of the engine 1 are stopped in an overlapped state, the EGR valve 24 is closed, so that air from the outside flows into the EGR passage 23. All of them are introduced into the combustion chamber 5 without passing through, and the intake of the inert gas to the exhaust side can be efficiently performed.

  Regardless of whether the intake valve and the exhaust valve are in an overlapped state, the evaporated fuel leaked from the intake-side injector 11 into the intake manifold 9 after the engine 1 is stopped is sucked into the exhaust pipe side. It becomes. Therefore, the evaporated fuel does not leak to the outside of the vehicle, and the surrounding environment and safety can be greatly improved. Further, since the evaporated fuel does not remain in the intake manifold 9, the air-fuel ratio at the next start of the engine 1 becomes appropriate, and good startability can be obtained.

  Further, according to the internal combustion engine stop control device of the present embodiment, the shielding valve 25 can be closed according to the timing at which the exhaust pressure generated even after the engine 1 is stopped disappears. Here, since the exhaust pressure generated after the engine 1 is stopped depends on the number of revolutions of the engine 1 before the stop, the shielding valve 25 can be closed at an appropriate timing. Accordingly, the shielding valve 25 is not closed despite the occurrence of exhaust pressure, and the load applied to each part of the exhaust system can be reduced and the reliability durability of each part can be improved. .

  Further, according to the internal combustion engine stop control device of the present embodiment, when the opening mechanism 26 is provided in the shielding valve 25, when the upstream side and the downstream side of the shielding valve 25 have a difference of a predetermined pressure or more, the shielding valve 25 The opening mechanism 26 is activated to allow the exhaust gas to flow from the upstream side to the downstream side. Thereby, the flow of the exhaust gas is not hindered by the shielding valve 25.

  Further, according to the internal combustion engine stop control device of the present embodiment, the opening degree of the throttle valve 19 is increased after the engine 1 is stopped, so that the flow resistance of the gas passing through the intake duct 15 is reduced. Therefore, the outside air can be efficiently introduced into the engine 1 when the inert gas contracts.

  Further, according to the internal combustion engine stop control device of the present embodiment, since the shielding valve 25 is provided at the connection portion between the exhaust pipe 10 and the muffler 22, maintenance of the shielding valve 25 and the like can be performed by removing the muffler 22 from the exhaust pipe 10. It can be performed and is extremely advantageous in practical use. Further, compared to the case where the exhaust pipe 10 is provided on the engine 1 side, the distance between the engine 1 serving as a heat source and the shielding valve 25 can be increased to reduce the thermal load applied to the shielding valve 25, thereby shielding the shielding. The reliability durability of the valve 25 can be ensured. Furthermore, by providing the shielding valve 25 on the downstream side of the exhaust pipe 10, the volume of the inert gas sealed in the exhaust pipe can be increased, and a larger contracting action can be obtained.

  In the above embodiment, the present invention is applied to the engine 1 mounted on the automobile vehicle. However, the present invention can be applied to any internal combustion engine. For example, the engine 1 used in ships, railway vehicles, and the like. It is also possible to apply to. Furthermore, the present invention can be applied to a prime mover used for an industrial machine or the like.

Moreover, in the said embodiment, what provided the shielding valve 25 in the connection part of the exhaust pipe 10 and the muffler 22 was shown, However, As long as it provides in an exhaust pipe, you may provide a shielding valve in any position.
That is, for example, as shown in FIG. 7, the shielding valve 125 may open and close the tail portion of the muffler 22 from the outside. Specifically, the shielding valve 125 includes a shaft member 125a fixed to the upper outer surface of the muffler 22, and a plate member 125b that is rotatably provided on the shaft member 125a and opens and closes the tail portion. The shielding valve 125 includes a spring member 126 that urges the plate member 125b in the closing direction. That is, when the shielding valve 125 is in a closed state, the shielding valve 125 has an opening mechanism that allows fluid flow from the upstream to the downstream when the upstream side and the downstream side of the shielding valve 25 have a difference of a predetermined pressure or more. Yes. The shielding valve 125 is not electrically controlled, and automatically opens and closes according to the urging force of the spring member 126 and the exhaust pressure in the muffler 22.

  In the above embodiment, the EGR valve 24 is closed when the intake valve and the exhaust valve are in the overlap state. However, even if the EGR valve 24 is opened in the overlap state, Outside air can be introduced into the fuel chamber 5 together with the EGR passage 23.

  In the above-described embodiment, the communication pipe using the EGR passage 23 is shown. However, for example, the communication pipe may be formed by excavating the communication pipe in the cylinder block 3 of the engine 1. Moreover, although what showed the time until the shielding valve 25 was made into a closed state based on the rotation speed of the engine 1 was shown, you may make it determine time based on the exhaust temperature etc. of the engine 1, In addition, it is needless to say that specific detailed structures and the like can be appropriately changed.

It is a schematic block diagram of the engine control system of the motor vehicle which shows one Embodiment of this invention. It is explanatory drawing of the exhaust system of a motor vehicle. It is explanatory drawing of a shielding valve, (a) shows the state closed, (b) shows an open state. It is a schematic block diagram of an engine control system. It is a set time table, (a) shows an idle switch in an OFF state, and (b) shows an idle switch in an ON state. It is a flowchart of the control system at the time of an engine stop. It is explanatory drawing of the shielding valve which shows a modification.

Explanation of symbols

1 Engine 10 Exhaust Pipe 19 Throttle Valve 22 Muffler 23 EGR Path 24 EGR Valve 25 Shielding Valve 26 Opening Mechanism 100 ECU
114 Shielding valve control program 115 EGR valve control program 116 Throttle valve control program 117 Overlap control program 125 Shielding valve 126 Spring member

Claims (5)

A shielding valve provided in an exhaust pipe connected to the internal combustion engine for opening and closing the inside of the pipe;
A communication valve that is provided in a communication pipe that communicates the intake side and the exhaust side of the internal combustion engine and opens and closes the inside of the pipe;
Shielding valve control means for closing the shielding valve after the operation of the internal combustion engine is stopped;
An internal combustion engine stop control device comprising: communication valve control means for opening the communication valve after the shielding valve is closed by the shielding valve control means.   When it is determined that the intake valve and the exhaust valve of the internal combustion engine are stopped in an overlapped state, an overlap control unit is provided that prohibits the operation of the communication valve control unit and closes the communication valve. 2. The internal combustion engine stop control device according to claim 1, wherein   The said shielding valve control means determines the time after an internal combustion engine stops to make a shielding valve into a closed state based on the operating speed before the stop of an internal combustion engine. The internal combustion engine stop control device described.   2. A throttle valve control means for increasing the opening of a throttle valve disposed in an intake pipe of an internal combustion engine after the shielding valve is closed by the shielding valve control means. The internal combustion engine stop control device according to claim 3.   The said shielding valve has an opening mechanism which accept | permits the distribution | circulation of the fluid from upstream to downstream, when a difference more than predetermined pressure becomes higher than a predetermined pressure between the upstream and downstream in the closed state. The internal combustion engine stop control device according to claim 4.

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