JP2006207466A - Decompression device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an increase in a manufacturing cost while improving the startability of an internal combustion engine in a decompression device for the internal combustion engine. <P>SOLUTION: This device is provided with a valve train operating hydraulic line 50 for supplying oil to an operating chamber 49 communicated with the high pressure chamber 64 of a lash adjuster 45 by a motor-driven oil pump 48, a decompression hydraulic line 52 for supplying oil to a decompression chamber 51 so as to push-press the lash adjuster 45 to a rocker arm 44 side by the motor-driven oil pump 48, and a hydraulic selector valve 53 for changing over these hydraulic lines 50, 52. When an engine is started, an engine starting/stopping pattern is set up by the hydraulic selector valve 53, and the valve train operating hydraulic line 50 and decompression hydraulic line 52 are opened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a decompression device for an internal combustion engine in which a valve operating mechanism of the internal combustion engine reduces the in-cylinder pressure when starting the internal combustion engine to improve startability.

  In a diesel engine, an in-cylinder injection engine, and the like, since the compression ratio is set high, the in-cylinder pressure becomes a starting resistance at the time of starting and vibration is generated. Therefore, various engine decompression devices have been proposed in which the in-cylinder pressure is reduced and the startability is improved when the engine is started.

  For example, in the “decompression device for an engine” described in Patent Document 1 below, one end of the rocker arm comes into contact with the camshaft, while the other end of the rocker arm engages with the upper end of the exhaust valve. The provided decompression cam is configured to act via the decompression piston. Therefore, when the compressor is not decompressed, the decompression piston is moved upward by the decompression cam, so that the exhaust valve is not pressed via the rocker arm and the exhaust port is closed. When the decompression piston moves downward, the exhaust valve is pressed through the rocker arm, the exhaust port is slightly opened, and the in-cylinder pressure is reduced.

JP 2001-263018 A

  The above-mentioned “decompression device for an engine” in Patent Document 1 uses a decompression device provided above the other end of the rocker arm to move a decompression piston by rotation of a decompression cam when the engine is started, and an exhaust valve via the rocker arm. By moving the exhaust port, the exhaust port is slightly opened to reduce the in-cylinder pressure and reduce the starting resistance. However, in this device, a decompression device composed of a number of members such as a decompression cam and a decompression piston is separately provided above the other end of the rocker arm with respect to the valve mechanism composed of a rocker arm and an exhaust valve. Provided. Therefore, the number of parts increases, the structure becomes complicated, and the number of assembly steps increases, resulting in an increase in manufacturing cost.

  An object of the present invention is to provide a decompression device for an internal combustion engine that improves the startability of the internal combustion engine while suppressing an increase in manufacturing cost.

  In order to solve the above-described problems and achieve the object, a decompression device for an internal combustion engine according to the present invention has one end of a rocker arm engaged with a hydraulic lash adjuster as a fulcrum, and the other end of the rocker arm is an intake valve. Alternatively, it acts on the exhaust valve, the substantially central portion of the rocker arm abuts on the intake cam or the exhaust cam, and the intake cam or the exhaust cam is operated by the action of the intake cam or the exhaust cam to set the intake port or the exhaust port. In a valve operating device of an internal combustion engine that opens and closes, a valve operating mechanism hydraulic line that supplies hydraulic oil to a high pressure chamber of the hydraulic lash adjuster by an electric oil pump, and the hydraulic lash adjuster by the electric oil pump connects the hydraulic lash adjuster to the rocker arm. A decompression hydraulic line for supplying hydraulic oil to the decompression chamber so as to press against the decompression chamber; And a control means for opening the switching valve when the internal combustion engine is started and supplying hydraulic oil to the decompression chamber by the decompression hydraulic line. To do.

  In the decompression device for an internal combustion engine according to the present invention, when the ignition key switch is turned on, the control means opens the switching valve and supplies hydraulic oil to the decompression chamber through the decompression hydraulic line. When the rotational speed of the engine becomes equal to or higher than a predetermined rotational speed set in advance, the switching valve is closed and the supply of hydraulic oil to the decompression chamber by the decompression hydraulic line is stopped.

  In the decompression device for an internal combustion engine according to the present invention, when the ignition key switch is turned off, the control means opens the switching valve and supplies hydraulic oil to the decompression chamber through the decompression hydraulic line. When the engine speed reaches zero, the switching valve is closed to stop the supply of hydraulic oil to the decompression chamber by the decompression hydraulic line.

  According to the decompression device for an internal combustion engine of the present invention, a valve operating device is constituted by a rocker arm, a hydraulic lash adjuster, an intake valve or an exhaust valve, and an intake cam or an exhaust cam, and an electric oil pump is used for the high pressure chamber of the hydraulic lash adjuster. There is a hydraulic line for operating the valve mechanism that supplies hydraulic oil to the engine, and a decompression hydraulic line that supplies hydraulic oil to the decompression chamber so that the hydraulic lash adjuster is pressed against the rocker arm by the electric oil pump. A switching valve is provided in the hydraulic line, and the control means opens the switching valve when the internal combustion engine is started, and supplies hydraulic oil to the decompression chamber through the decompression hydraulic line.

  Therefore, when the internal combustion engine is started, the switching valve is opened, and the hydraulic oil is supplied to the decompression chamber of the hydraulic lash adjuster through the hydraulic line for decompression by the electric oil pump. Therefore, the hydraulic lash adjuster is pressed toward the rocker arm. As a result, the intake valve or the exhaust valve is pushed down via the rocker arm, the intake port or the exhaust port is slightly opened, the in-cylinder pressure escapes to the intake port or the exhaust port, and the in-cylinder pressure is reduced, Generation of vibrations can be suppressed and startability can be improved, and since an existing hydraulic lash adjuster is used, a significant increase in manufacturing cost can be suppressed.

  Embodiments of a decompression device for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic configuration diagram of a decompression device for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing a decompression state in the decompression device for an internal combustion engine of the present embodiment, and FIG. FIG. 4 is a schematic diagram showing a non-decompression state in the decompression device of the internal combustion engine of FIG. 4, FIG. 4 is a flowchart showing control at the time of engine start in the decompression device of the internal combustion engine of the present embodiment, and FIG. FIG. 6 is a schematic configuration diagram of an engine to which the internal combustion engine decompression device according to the present embodiment is applied.

  In the internal combustion engine to which the decompression device for the internal combustion engine of the present embodiment is applied, as shown in FIG. 6, a diesel engine 11 as an internal combustion engine is not shown, but a cylinder head is fastened on a cylinder block. Pistons are respectively fitted to the cylinder bores so as to be movable up and down. A crankcase is fastened to the lower part of the cylinder block, a crankshaft is rotatably supported in the crankcase, and each piston is connected to the crankshaft via a connecting rod.

  A plurality of (four in this embodiment) combustion chambers 12 are constituted by the cylinder block, the cylinder head, and the piston, and the combustion chamber 12 is formed with an intake port 13 and an exhaust port 14 facing each other at the upper part. The lower ends of the intake valve and the exhaust valve (not shown) are positioned with respect to the intake port 13 and the exhaust port 14, respectively. The intake valve and the exhaust valve are supported by the cylinder head so as to be movable along the axial direction, and are urged and supported in a direction to close the intake port 13 and the exhaust port 14. An intake cam shaft and an exhaust cam shaft are rotatably supported by the cylinder head, and the intake cam and the exhaust cam are in contact with upper ends of the intake valve and the exhaust valve via a roller rocker arm.

  Therefore, when the intake cam shaft and the exhaust cam shaft rotate in synchronization with the engine 11, the intake cam and the exhaust cam operate the roller rocker arm, and the intake valve and the exhaust valve move up and down at a predetermined timing, whereby the intake port 13 The exhaust port 14 can be opened and closed to allow the intake port 13 and the combustion chamber 12 to communicate with the combustion chamber 12 and the exhaust port 14, respectively.

  An intake pipe 16 is connected to the intake port 13 via an intake manifold 15, and an air cleaner 17 is attached to an air intake port of the intake pipe 16. An electronic throttle device 18 having a throttle valve is provided downstream of the air cleaner 17. Each cylinder head is provided with an injector 19 capable of injecting gasoline as fuel at a high pressure in each combustion chamber 12. Each injector 19 is connected to a fuel pump 21 via a delivery pipe 20, and the fuel pump 21 is driven by the engine 11. On the other hand, an exhaust pipe 23 is connected to the exhaust port 14 via an exhaust manifold 22.

  Further, a turbocharger 24 is provided in the intake pipe 16 and the exhaust pipe 23. The turbocharger 24 is configured such that a compressor 24a provided in the intake pipe 16 and a turbine 24b provided in the exhaust pipe 23 are integrally connected by a drive shaft 24c. An intercooler that cools the intake air that has been supercharged by the compressor 24a and has risen in temperature to the intake pipe 16 downstream of the compressor 24a in the turbocharger 24 and upstream of the throttle valve 18. 25 is provided.

  The exhaust pipe 23 is provided with an exhaust purification device 26 that purifies harmful substances contained in the exhaust gas. The exhaust purification device 26 is an NOx storage reduction catalyst having a particulate filter, and the exhaust gas Fine particles (PM: particulates), particularly black smoke, are collected, and NOx in the exhaust gas is occluded when the exhaust air-fuel ratio is lean, and occluded when the oxygen concentration in the exhaust gas is reduced. The NOx is released and reduced and regenerated by the added fuel as a reducing agent (in this embodiment, light oil). Therefore, a fuel addition valve 27 that injects fuel into the exhaust port 13 of the engine 11 is provided. The fuel addition valve 27 is connected to the fuel pump 21 via a fuel supply pipe (not shown).

  The engine 11 is provided with an exhaust gas recirculation (EGR) device 28 that returns a part of the exhaust gas to the intake system. The EGR device 28 includes an EGR passage 29 that connects the exhaust manifold 22 and the intake pipe 16 immediately before the intake manifold 15 to recirculate a part of the exhaust gas to the intake system, and an EGR provided in the EGR passage 29. It comprises a valve 30 and an EGR cooler 31 that is provided in the EGR passage 29 and cools the exhaust gas.

  By the way, an electronic control unit (ECU) 32 is mounted on the vehicle, and this ECU 32 can control the fuel injection timing of the injector 19 and the ignition timing of a spark plug (not shown). The fuel injection amount, the injection timing, the ignition timing, and the like are determined based on the engine operation state such as the air amount, the intake air temperature, the throttle opening, the accelerator opening, the engine speed, and the cooling water temperature. That is, an airflow sensor 33 and an intake air temperature sensor 34 are mounted on the upstream side of the intake pipe 16, and the measured intake air amount and intake air temperature are output to the ECU 32. The electronic throttle device 18 is provided with a throttle position sensor, and the accelerator pedal is provided with an accelerator position sensor 35, which outputs the current throttle opening and accelerator opening to the ECU 32. Further, a crank angle sensor 36 is provided on the crankshaft, and the detected crank angle is output to the ECU 32. The ECU 32 calculates the engine speed based on the crank angle. The cylinder block is provided with a water temperature sensor 37 and outputs the detected engine cooling water temperature to the ECU 32.

  The ECU 32 controls the drive of the EGR device 28 according to the engine operating state. That is, by adjusting the opening degree of the EGR valve 30 in a predetermined engine operating state, exhaust gas is circulated as EGR gas to the intake system through the EGR passage 29, and the combustion temperature is lowered to suppress generation of NOx.

  Further, the ECU 32 regenerates the exhaust purification device 26 at a predetermined time. That is, when the engine 11 is operated at a lean air-fuel ratio, the exhaust purification device 26 stores PM and NOx in the exhaust gas. When the NOx occlusion amount of the exhaust purification device 26 reaches a predetermined value, the ECU 32 controls the fuel addition valve 27 and injects a predetermined amount of fuel into the exhaust port 14 as a reducing agent. Then, the fuel is supplied to the exhaust purification device 26 through the exhaust pipe 23, and the oxygen concentration in the exhaust gas is lowered by the oxidation reaction, so that the NOx occluded in the exhaust purification device 26 is released, and the released NOx and The fuel reacts and is reduced, and the exhaust gas is purified to be regenerated. At this time, the catalyst temperature rises due to the oxidation reaction, so that the PM collected in the exhaust purification device 26 is burned and regenerated.

  By the way, in the diesel engine 11 of the present embodiment, since the compression ratio is set high, the in-cylinder pressure may become a starting resistance at the time of starting and vibration may occur. For the purpose of improving, a decompression device is mounted on the intake side of the valve operating mechanism.

  That is, as shown in FIG. 1, the intake port 13 is formed in the upper part of the combustion chamber 12 provided in the engine body (for example, cylinder head) 41, and the intake valve 42 is positioned with respect to the intake port 13. ing. The intake valve 42 is supported by a stem guide (not shown) fixed to the engine body 41 so as to be movable along the axial direction, and is urged and supported by a valve spring 43 in a direction to close the intake port 13. Yes. The intake valve 42 is engaged with one end of a rocker arm 44 at the upper end, and the other end of the rocker arm 44 is engaged with a hydraulic lash adjuster 45 supported movably on the engine body 41. . The intake cam 47 of the intake cam shaft 46 is engaged so as to press the intermediate portion of the rocker arm 44.

  Therefore, when the intake camshaft 46 rotates in synchronization with the diesel engine 11, the intake cam 47 operates the rocker arm 44, and the intake valve 42 moves up and down at a predetermined timing, thereby opening and closing the intake port 13 and the intake port 13 13 and the combustion chamber 12 can be communicated with each other.

  The lash adjuster 45 adjusts the gaps between the components in the valve mechanism, and can reduce the operating noise and wear during operation of the valve mechanism. The lash adjuster 45 includes a plunger 61 and a housing 62. The plunger 61 is movably fitted in the housing 62, and there is a minute clearance that allows sliding between the two. The plunger 61 has a low-pressure chamber 63 inside, and the housing 62 has a high-pressure chamber 64 inside. Oil (hydraulic oil) is introduced into the low-pressure chamber 63 through the oil passage of the plunger 61 and the oil passage of the housing 62. The oil in the high pressure chamber 64 leaks outside through the clearance. The low pressure chamber 63 and the high pressure chamber 64 can be inserted through an oil inflow hole 65, and the oil inflow hole 65 is closed by a check ball 67 biased and supported by a spring 66. A plunger spring 68 is provided between the housing 62 and the plunger 61 to urge the plunger 61 in a direction protruding from the housing 62.

  Accordingly, when the camshaft 46 rotates and the intake cam 47 pushes the rocker arm 44, a load is applied to both the intake valve 42 and the plunger 61 of the lash adjuster 45, and the plunger 61 tends to be pushed in. Since the oil inflow hole 65 is closed, the plunger 61 stops, and the rocker arm 44 rotates about the top of the lash adjuster 45 to push down the intake valve 42 to open the intake port 13. When the intake cam 47 passes the apex, the rocker arm 44 is pushed up by the valve spring 43, and when the intake valve 42 closes the intake port 13, the oil in the high pressure chamber 64 is released from the pressurized state, and the plunger spring 68 releases the plunger 61. The valve clearance is maintained at 0 by being pushed up. At the same time, the high-pressure chamber 64 becomes larger in volume and the check ball 67 is separated from the oil inflow hole 65 due to the pressure difference with the low-pressure chamber 63, and oil flows from the low-pressure chamber 63 into the high-pressure chamber 64 to prepare for the next operation.

  The diesel engine 11 is provided with an electric oil pump 48 that can be operated by the ECU 32. The electric oil pump 48 pushes the lash adjuster 45 toward the rocker arm 44 by the valve operating mechanism hydraulic line 50 for supplying oil to the working chamber 49 communicating with the high pressure chamber 64 of the lash adjuster 45. A decompression hydraulic line 52 that supplies oil to the decompression chamber 51 is provided. A hydraulic pressure switching valve 53 is provided between the electric oil pump 48 and the valve operating mechanism actuation hydraulic line 50 and decompression hydraulic line 52. The hydraulic pressure switching valve 53 can be operated by the ECU 32. In other words, the ECU 32 supplies oil from the electric oil pump 48 to the working chamber 49 via the hydraulic valve 50 for operating the valve operating mechanism by the hydraulic switching valve 53, and supplies oil to the decompression chamber 51 via the decompression hydraulic line 52. Can be switched between an engine start / stop pattern for supplying oil and an engine operation pattern for supplying oil only from the electric oil pump 48 to the working chamber 49 via the hydraulic valve 50 for operating the valve mechanism.

  The lash adjuster 45 is formed with a flange portion 54 at the top, and a stopper 55 is formed on the engine main body 41 to define a movement range of the lash adjuster 45.

  Therefore, in the engine start / stop pattern, oil is supplied from the electric oil pump 48 to the working chamber 49 via the valve operating mechanism operating hydraulic line 50, and oil is supplied to the decompression chamber 51 via the decompressing hydraulic line 52. Thus, the valve clearance is properly maintained by the operation of the lash adjuster 45 described above, and the lash adjuster 45 moves to the rocker arm 44 side, and the intake valve 42 is pushed down via the rocker arm 44. It opens slightly and the pressure in the cylinder is reduced. In the engine operation pattern, the lash adjuster 45 returns to the proper position by supplying oil from the electric oil pump 48 to the working chamber 49 via the hydraulic valve 50 for operating the valve mechanism. Clearance is maintained properly.

  Here, the control at the time of engine start by the decompression device of the internal combustion engine of the present embodiment will be described.

  In the control at the time of engine start by the decompression device of the internal combustion engine of the present embodiment, as shown in FIG. 4, the ignition key switch (IG) is turned on while the diesel engine 11 is stopped in step S11. When the determination is made, the ECU 32 operates the electric oil pump 48 in step S12, and switches the hydraulic line to the engine start / stop pattern by the hydraulic switching valve 53 in step S13. That is, as shown in FIG. 2, in an engine start / stop pattern, oil is supplied from the electric oil pump 48 to the working chamber 49 via the valve operating mechanism hydraulic line 50, and via the decompression hydraulic line 52. Oil is supplied to the decompression chamber 51. Then, when oil is supplied to the decompression chamber 51, the lash adjuster 45 moves toward the rocker arm 44 until it abuts against the stopper 55, and the rocker arm 44 rotates to push down the intake valve 42, so that the intake port 13 is slightly changed. To open. Further, by supplying oil to the working chamber 49, the valve clearance is properly maintained by the operation of the lash adjuster 45.

  Thereafter, as shown in FIG. 4, in step S14, a starter motor (not shown) is operated to perform cranking, and in step S15, it is confirmed that the engine speed has reached a predetermined speed, for example, 300 rpm or more. Then, the ECU 32 switches the hydraulic line to the engine start / stop pattern by the hydraulic switching valve 53 in step S16. That is, as shown in FIG. 3, in the engine operation pattern, the oil is supplied from the electric oil pump 48 to the working chamber 49 via the valve operating mechanism hydraulic line 50, while the decompression chamber from the decompression hydraulic line 52 is supplied. The oil supply to 51 is stopped. Then, the oil in the decompression chamber 51 flows out of the minute clearance between the engine main body 41 and the lash adjuster 45, so that the lash adjuster 45 moves to the opposite side of the rocker arm 44, and the pressure of the rocker arm 44 is released. The intake valve 42 is raised by the valve spring 43 to close the intake port 13. In step S17, the injector 19 starts fuel injection.

  That is, when the diesel engine 11 is started, cranking by the starter motor is started with the intake port 13 slightly opened, and the piston moves while the pressure in the cylinder is reduced. The resistance is reduced and the occurrence of vibrations at the time of starting the engine is suppressed, so that startability can be improved.

  Next, control when the engine is stopped by the decompression device for the internal combustion engine of the present embodiment will be described.

  In the control at the time of engine stop by the decompression device of the internal combustion engine of this embodiment, as shown in FIG. 5, the ignition key switch (IG) is turned off during operation of the diesel engine 11 in step S21. When the determination is made, the ECU 32 switches the hydraulic line to the engine start / stop pattern by the hydraulic switching valve 53 in step S22. That is, as shown in FIG. 2, in an engine start / stop pattern, oil is supplied from the electric oil pump 48 to the working chamber 49 via the valve operating mechanism hydraulic line 50, and via the decompression hydraulic line 52. Oil is supplied to the decompression chamber 51. Then, when oil is supplied to the decompression chamber 51, the lash adjuster 45 moves toward the rocker arm 44 until it abuts against the stopper 55, and the rocker arm 44 rotates to push down the intake valve 42, so that the intake port 13 is slightly changed. To open. Further, by supplying oil to the working chamber 49, the valve clearance is properly maintained by the operation of the lash adjuster 45.

  Thereafter, as shown in FIG. 5, in step S23, the fuel injection by the injector 19 is stopped, and in step S24, when it is confirmed that the engine speed has become 0 rpm, the ECU 32 in step S25, The hydraulic pressure switching valve 53 switches the hydraulic line to the engine start / stop pattern. That is, as shown in FIG. 3, in the engine operation pattern, the oil is supplied from the electric oil pump 48 to the working chamber 49 via the valve operating mechanism hydraulic line 50, while the decompression chamber from the decompression hydraulic line 52 is supplied. The oil supply to 51 is stopped. Then, the oil in the decompression chamber 51 flows out of the minute clearance between the engine main body 41 and the lash adjuster 45, so that the lash adjuster 45 moves to the opposite side of the rocker arm 44, and the pressure of the rocker arm 44 is released. The intake valve 42 is raised by the valve spring 43 to close the intake port 13. In step S26, the electric oil pump 48 is stopped.

  That is, when the diesel engine 11 is stopped, the fuel injection is stopped and the engine speed is stopped with the intake port 13 being slightly opened, and the piston moves while the pressure in the cylinder is reduced. Therefore, the starting resistance is reduced and the generation of vibrations at the time of starting the engine is suppressed, so that the startability can be improved.

  As described above, in the decompression device for the internal combustion engine of the first embodiment, the rocker arm 44, the hydraulic lash adjuster 45, the intake valve 42, the intake cam 47, and the like constitute a valve operating mechanism, and the electric oil pump 48 provides the lash adjuster. The oil is supplied to the decompression chamber 51 so as to press the lash adjuster 45 to the rocker arm 44 side by the hydraulic valve 50 for operating the valve operating mechanism for supplying oil to the working chamber 49 communicating with the high pressure chamber 64 of 45. And a hydraulic pressure switching valve 53 for switching between the hydraulic lines 50 and 51. The ECU 32 sets an engine start / stop pattern by the hydraulic pressure switching valve 53 when the engine is started. 50 and the decompression hydraulic line 52 are opened. There.

  Therefore, when the engine is started, an engine start / stop pattern is set, and oil is supplied from the electric oil pump 48 to the working chamber 49 via the hydraulic valve for actuating the valve mechanism, and to the decompression chamber 51 via the decompression hydraulic line 52. Is supplied with oil. Then, by supplying oil to the decompression chamber 51, the lash adjuster 45 moves to the rocker arm 44 side, the rocker arm 44 rotates to push down the intake valve 42, and the intake port 13 is slightly opened. The in-cylinder pressure escapes to the intake port 13 and the in-cylinder pressure is reduced, so that the occurrence of vibration at the time of engine start is suppressed and startability can be improved.

  Similarly, when the engine is stopped, the engine start / stop pattern is used, and oil is supplied from the electric oil pump 48 to the working chamber 49 via the valve operating mechanism operating hydraulic line 50 and also via the decompression hydraulic line 52. Then, oil is supplied to the decompression chamber 51. Then, by supplying oil to the decompression chamber 51, the lash adjuster 45 moves to the rocker arm 44 side, the rocker arm 44 rotates to push down the intake valve 42, and the intake port 13 is slightly opened. The in-cylinder pressure escapes to the intake port 13, the in-cylinder pressure is reduced, and the occurrence of vibration when the engine is stopped can be suppressed.

  In this case, a decompression function for reducing vibration suppression at the time of engine start and stop is added using the existing hydraulic lash adjuster 45, thereby suppressing a significant increase in manufacturing cost by simplifying the configuration. be able to.

  Also, in this embodiment, the internal combustion engine decompression device of the present invention is applied to the intake side lash adjuster 45 in the engine valve mechanism, so that the residual gas in the combustion chamber is taken into the intake air when the intake port 13 is slightly opened. Although it flows out to the system, this residual gas is again introduced into the combustion chamber after the engine is started, so that the unburned gas is not released into the atmosphere.

  In the embodiment described above, a hydraulic pressure switching valve 53 is provided between the electric oil pump 48, the valve operating mechanism operating hydraulic line 50, and the decompression hydraulic line 52. It is possible to switch between an engine start / stop pattern in which the valve mechanism actuation hydraulic line 50 and decompression hydraulic line 52 are opened, and an engine operation pattern in which only the valve actuation mechanism hydraulic line 50 is opened. A valve operating mechanism actuation hydraulic line 50 and a decompression hydraulic line 52 are provided in parallel. A hydraulic switching valve 53 is provided in the decompression hydraulic line 52. By opening and closing the hydraulic switching valve 53, an engine start / stop pattern is provided. And an engine operation pattern.

  In the above-described embodiment, the decompression device for the internal combustion engine of the present invention is applied to the intake side lash adjuster 45 in the engine valve mechanism, but may be applied to the exhaust side lash adjuster. In this case, when the exhaust port 14 is slightly opened, the residual gas in the combustion chamber flows out into the exhaust system, but this residual gas is purified by the exhaust purification device 26 provided in the exhaust pipe 23, so that it remains unburned. Gas is not released into the atmosphere.

  As described above, the decompression device for an internal combustion engine according to the present invention suppresses a significant increase in manufacturing cost by adding a decompression function to an existing hydraulic lash adjuster. It is useful when applied to the valve mechanism.

1 is a schematic configuration diagram of a decompression device for an internal combustion engine according to an embodiment of the present invention. It is the schematic showing the decompression state in the decompression apparatus of the internal combustion engine of a present Example. It is the schematic showing the non-decompression state in the decompression apparatus of the internal combustion engine of a present Example. It is a flowchart showing the control at the time of engine starting in the decompression apparatus of the internal combustion engine of a present Example. It is a flowchart showing the control at the time of an engine stop in the decompression apparatus of the internal combustion engine of a present Example. 1 is a schematic configuration diagram of an engine to which a decompression device for an internal combustion engine according to an embodiment is applied.

Explanation of symbols

11 Diesel engine (internal combustion engine)
12 Combustion chamber 13 Intake port 32 Electronic control unit, ECU (control means)
41 Engine Body 42 Intake Valve 44 Rocker Arm 45 Rush Adjuster 46 Intake Cam Shaft 47 Intake Cam 48 Electric Oil Pump 49 Working Chamber 50 Valve Operating Mechanism Acting Hydraulic Line 51 Decompression Chamber 52 Decompression Hydraulic Line 53 Hydraulic Switch Valve 64 High Pressure Chamber

Claims (3)

  One end of the rocker arm engages with the hydraulic lash adjuster as a fulcrum, the other end of the rocker arm acts on the intake valve or the exhaust valve, and the substantially central portion of the rocker arm contacts the intake cam or the exhaust cam. In a valve operating device for an internal combustion engine that opens and closes an intake port or an exhaust port by operating the intake valve or the intake / exhaust valve by the action of an intake cam or an exhaust cam, the electric oil pump operates the high pressure chamber of the hydraulic lash adjuster. A hydraulic line for operating a valve mechanism that supplies oil, a hydraulic line for decompression that supplies hydraulic oil to the decompression chamber so as to press the hydraulic lash adjuster toward the rocker arm by the electric oil pump, and the hydraulic pressure for decompression A switching valve provided in the line, and the switching valve when the internal combustion engine is started. The open decompression device for an internal combustion engine, characterized in that it comprises a control means for supplying hydraulic fluid to the decompression chamber by the decompression hydraulic line.   The decompression device for an internal combustion engine according to claim 1, wherein when the ignition key switch is turned on, the control means opens the switching valve and supplies hydraulic oil to the decompression chamber by the decompression hydraulic line, When the rotational speed of the internal combustion engine becomes equal to or higher than a predetermined rotational speed set in advance, the switching valve is closed to stop supplying hydraulic oil to the decompression chamber by the decompression hydraulic line. Decompression device. The decompression device for an internal combustion engine according to claim 1, wherein when the ignition key switch is turned off, the control means opens the switching valve and supplies hydraulic oil to the decompression chamber through the decompression hydraulic line, A decompression device for an internal combustion engine, wherein when the rotational speed of the internal combustion engine becomes 0, the switching valve is closed to stop the supply of hydraulic oil to the decompression chamber by the decompression hydraulic line.

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