JP5104487B2 - Multi-cylinder internal combustion engine - Google Patents

Description

  The present invention provides a valve spring that urges the exhaust valve in the closing direction, a lash adjuster that presses the exhaust valve in the opening direction to adjust the position of the valve, and an exhaust valve that cooperates with the valve spring and the lash adjuster. The present invention relates to a multi-cylinder internal combustion engine provided with a cam for opening and closing each cylinder.

An example of this type of multi-cylinder internal combustion engine is disclosed in Patent Document 1. In such multi-cylinder internal combustion engines, including those described in Patent Document 1, an exhaust manifold is connected to the exhaust downstream side of the exhaust port of each cylinder, and the exhaust discharged from each cylinder passes through the exhaust port and the exhaust manifold. Collected in an exhaust pipe connected to the downstream side. For this reason, when exhaust gas is discharged from a certain cylinder, the exhaust pressure in the exhaust manifold and the exhaust port temporarily increases accordingly, and exhaust gas is discharged sequentially from each cylinder, that is, fluctuations in exhaust pressure, that is, Exhaust pulsation occurs.
JP 2006-226266 A

  By the way, in an internal combustion engine provided with a supercharger, for example, the pressure of exhaust gas may become excessively high. In this case, the following problems occur. That is, a force based on the pressure of the exhaust acts on the exhaust valve in the direction of opening the valve, and the pressing force of the lash adjuster acts on the exhaust valve in the direction of opening the valve. The urging force of the valve spring acts on the exhaust valve in the direction of closing the valve. Here, when the exhaust pressure becomes excessively high, the resultant force of the force based on the exhaust pressure and the pressing force of the lash adjuster among the forces acting on the exhaust valve is larger than the urging force of the valve spring. As a result, the hydraulic lash adjuster is pumped up, resulting in a seating failure such that the exhaust valve cannot be seated stably on the valve seat.

  Further, when the engine speed is high, valve surging is likely to occur, and when such valve surging occurs, the urging force of the valve spring acting on the exhaust valve is temporarily reduced. For this reason, even in such a case, there is a possibility that the above-described poor seating may occur.

  To deal with these problems, it is conceivable to use a valve spring having a larger spring coefficient in order to increase the urging force of the valve spring. In this case, however, a new engine resistance increases as the exhaust valve opens and closes. Will cause serious problems.

  The present invention has been made in view of such circumstances, and the object thereof is to reduce exhaust pressure due to excessively high exhaust pressure while suppressing an increase in engine resistance due to exhaust valve opening / closing drive. An object of the present invention is to provide a multi-cylinder internal combustion engine capable of suppressing the occurrence of valve seating failure.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is a valve spring that biases the valve in the closing direction of the exhaust valve, and a hydraulic lash adjuster that presses the valve in the opening direction of the exhaust valve and adjusts the position of the valve. Each cylinder is provided with a cam for opening and closing the exhaust valve in cooperation with the valve spring and the hydraulic lash adjuster, and an exhaust port for switching the communication state with the combustion chamber as the exhaust valve is opened and closed. In a multi-cylinder internal combustion engine having an exhaust manifold connected to the exhaust downstream side of these exhaust ports, a variable valve mechanism that makes the opening timing of the exhaust valve variable, and an exhaust valve calculated based on the engine operating state Control means for controlling the variable valve mechanism according to the target valve opening timing, and the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure And a correcting means for correcting the valve opening timing of the exhaust valve to the retard side from the target valve opening timing when the certain fact estimation, the correction means, pressure detection for detecting the pressure in the intake of an internal combustion engine Means that when the intake pressure detected by the pressure detection means is greater than or equal to a predetermined pressure, the internal pressure of the exhaust manifold is estimated to be greater than or equal to a predetermined pressure, and when the internal pressure of the exhaust manifold is high, The gist of the invention is to set the retard correction amount of the valve opening timing of the exhaust valve to a large value .

  According to the above configuration, when the variable valve mechanism is controlled in accordance with the target valve opening timing, if the exhaust pressure becomes excessively high, the valve opening timing of the exhaust valve is corrected more retarded than the target valve opening timing. Therefore, the exhaust valve is opened after the pressure in the cylinder becomes lower than in the case where such retardation correction is not performed. As a result, the pressure of the exhaust gas discharged from the cylinder becomes low, and the exhaust pressure can be prevented from becoming excessively high. As a result, the force based on the pressure of the exhaust acting on the exhaust valve of the other cylinder in the direction of opening the valve and the pressing force of the hydraulic lash adjuster acting on the exhaust valve in the direction of opening the valve. The resultant force can be prevented from becoming larger than the urging force of the valve spring acting in the direction of closing the valve with respect to the exhaust valve, and the occurrence of pump-up of the hydraulic lash adjuster can be suppressed. Become. Therefore, it is possible to suppress the occurrence of poor seating of the exhaust valve due to excessive increase in the exhaust pressure while suppressing the increase in engine resistance due to the opening / closing drive of the exhaust valve.

In addition, since the internal pressure of the exhaust manifold can be estimated by grasping the intake pressure, it is estimated that the internal pressure of the exhaust manifold is equal to or higher than the predetermined pressure when the intake pressure is equal to or higher than the predetermined pressure, as described above. By doing so, it is possible to determine whether or not to correct the valve opening timing of the exhaust valve to the retard side with respect to the target valve opening timing without directly detecting the internal pressure of the exhaust manifold.

Furthermore, according to the above configuration, even when the exhaust valve pressure increases when the variable valve mechanism is controlled according to the target valve opening timing, the retardation correction amount is set according to the degree. The exhaust valve is opened after the pressure in the cylinder becomes sufficiently low. Thereby, the pressure of the exhaust gas discharged from the cylinder can be accurately reduced. Therefore, the occurrence of pump-up of the hydraulic lash adjuster can be accurately suppressed.

According to a second aspect of the invention, in multi-cylinder internal combustion engine according to claim 1, wherein the hydraulic lash adjuster which is driven by the pressure of oil supplied from the oil pump of the engine-driven, the correction The gist of the means is that the predetermined pressure is set to a smaller value when the engine speed is high than when the engine speed is low.

  When the predetermined pressure for determining whether or not to correct the exhaust valve opening timing to the retarded angle side relative to the target valve opening timing is a constant value, for example, the pressing force of the hydraulic lash adjuster is assumed to be previously If the pressure is too large, the hydraulic lash adjuster pumps up even though the internal pressure of the exhaust manifold is smaller than the predetermined pressure, resulting in poor seating of the exhaust valve. On the other hand, in a hydraulic lash adjuster driven by the pressure of oil supplied from an engine-driven oil pump, the oil pressure is higher when the engine speed is high than when it is low. The pressing force of the adjuster increases. In view of these, as in the above configuration, when the engine pressure is high, the predetermined pressure is set to a smaller value than when the engine speed is low, and when the pressing force of the hydraulic lash adjuster is large, The predetermined pressure can be set to a small value compared to the above, and the predetermined pressure can be accurately set according to the pressing force of the hydraulic lash adjuster. Therefore, although the internal pressure of the exhaust manifold is smaller than the predetermined pressure, it is possible to prevent the hydraulic lash adjuster from being pumped up, and to suppress the occurrence of poor seating of the exhaust valve. It becomes like this.

The invention according to claim 3, in multi-cylinder internal combustion engine according to claim 1, wherein the hydraulic lash adjuster which is driven by the pressure of oil supplied from the oil pump of the engine-driven, the oil An oil temperature detecting means for detecting the temperature of the oil, and the correction means sets the predetermined pressure to a larger value when the oil temperature detected by the oil temperature detecting means is high than when the oil temperature is low. It is said.

  When the predetermined pressure for determining whether or not to correct the exhaust valve opening timing to the retarded angle side relative to the target valve opening timing is a constant value, for example, the pressing force of the hydraulic lash adjuster is assumed to be previously If the pressure is too large, the hydraulic lash adjuster pumps up even though the internal pressure of the exhaust manifold is smaller than the predetermined pressure, resulting in poor seating of the exhaust valve. On the other hand, in a hydraulic lash adjuster driven by the pressure of oil supplied from an engine-driven oil pump, the viscosity and viscosity of the oil is lower when the oil temperature is higher than when the oil temperature is low. Since the amount of oil leaking from the tank increases, the pressing force of the lash adjuster decreases. In view of these, as in the above configuration, when the oil pressure is high, the predetermined pressure is set to a larger value than when the oil temperature is low, and when the pressing force of the hydraulic lash adjuster is small, The predetermined pressure can be set to a large value as compared with the above, and the predetermined pressure can be accurately set according to the pressing force of the hydraulic lash adjuster. Therefore, although the internal pressure of the exhaust manifold is smaller than the predetermined pressure, it is possible to prevent the hydraulic lash adjuster from being pumped up, and to suppress the occurrence of poor seating of the exhaust valve. It becomes like this.

The invention according to claim 4, in multi-cylinder internal combustion engine according to claim 1, wherein the hydraulic lash adjuster which is driven by the pressure of oil supplied from the oil pump of the engine-driven, engine cooling Water temperature detecting means for detecting the temperature of the water, and the correction means sets the predetermined pressure to a larger value when the temperature of the engine cooling water detected by the water temperature detecting means is high than when the temperature is low. It is a summary.

When the predetermined pressure for determining whether or not to correct the exhaust valve opening timing to the retarded angle side relative to the target valve opening timing is a constant value, for example, the pressing force of the hydraulic lash adjuster is assumed to be previously If the pressure is too large, the hydraulic lash adjuster pumps up even though the internal pressure of the exhaust manifold is smaller than the predetermined pressure, resulting in poor seating of the exhaust valve. On the other hand, in a hydraulic lash adjuster driven by the pressure of oil supplied from an engine-driven oil pump, the viscosity and viscosity of the oil is lower when the oil temperature is higher than when the oil temperature is low. Since the amount of oil leaking from the tank increases, the pressing force of the lash adjuster decreases. On the other hand, the temperature of the oil can be estimated by grasping the temperature of the engine cooling water. In view of these, as described above, when the temperature of the engine cooling water is high, the predetermined pressure is set to a larger value than when the temperature is low, and when the pressing force of the hydraulic lash adjuster is small. The predetermined pressure can be set to a larger value than when it is large, and the predetermined pressure can be accurately set according to the pressing force of the hydraulic lash adjuster. Therefore, although the internal pressure of the exhaust manifold is smaller than the predetermined pressure, it is possible to prevent the hydraulic lash adjuster from being pumped up, and to suppress the occurrence of poor seating of the exhaust valve. It becomes like this.
According to a fifth aspect of the present invention, there is provided a valve spring that biases the valve in the closing direction of the exhaust valve, a hydraulic lash adjuster that presses the valve in the opening direction of the exhaust valve and adjusts the position of the valve. Each cylinder is provided with a cam for opening and closing the exhaust valve in cooperation with the valve spring and the hydraulic lash adjuster, and an exhaust port for switching the communication state with the combustion chamber as the exhaust valve is opened and closed. In a multi-cylinder internal combustion engine having an exhaust manifold connected to the exhaust downstream side of these exhaust ports, a variable valve mechanism that makes the opening timing of the exhaust valve variable, and an exhaust valve calculated based on the engine operating state Control means for controlling the variable valve mechanism according to the target valve opening timing, and the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure Correction means for correcting the valve opening timing of the exhaust valve to be retarded from the target valve opening timing when it is estimated that the hydraulic lash adjuster is supplied from an engine-driven oil pump The correction means includes pressure detection means for detecting the pressure of the intake air of the internal combustion engine, and the correction means exhausts when the pressure of the intake air detected by the pressure detection means is equal to or higher than a predetermined pressure. The gist is to estimate that the internal pressure of the manifold is equal to or higher than a predetermined pressure, and to set the predetermined pressure to a smaller value when the engine speed is high than when the engine speed is low.
According to a sixth aspect of the present invention, there is provided a valve spring that urges the valve in the closing direction of the exhaust valve, a hydraulic lash adjuster that adjusts the position of the valve by pressing the valve in the opening direction of the exhaust valve, and Each cylinder is provided with a cam for opening and closing the exhaust valve in cooperation with the valve spring and the hydraulic lash adjuster, and an exhaust port for switching the communication state with the combustion chamber as the exhaust valve is opened and closed. In a multi-cylinder internal combustion engine having an exhaust manifold connected to the exhaust downstream side of these exhaust ports, a variable valve mechanism that makes the opening timing of the exhaust valve variable, and an exhaust valve calculated based on the engine operating state Control means for controlling the variable valve mechanism according to the target valve opening timing, and the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure Correction means for correcting the valve opening timing of the exhaust valve to be retarded from the target valve opening timing when it is estimated that the hydraulic lash adjuster is supplied from an engine-driven oil pump It is driven by oil pressure, and includes oil temperature detection means for detecting the temperature of the oil, and the correction means includes pressure detection means for detecting the pressure of the intake air of the internal combustion engine, and the pressure detection means When the detected intake pressure is equal to or higher than the predetermined pressure, it is estimated that the internal pressure of the exhaust manifold is equal to or higher than the predetermined pressure, and when the oil temperature detected by the oil temperature detecting means is high, the predetermined pressure is lower than when it is low. The gist is to set a large value.
The invention according to claim 7 is a valve spring that urges the valve in the closing direction of the exhaust valve, a hydraulic lash adjuster that presses the valve in the opening direction of the exhaust valve and adjusts the position of the valve. Each cylinder is provided with a cam for opening and closing the exhaust valve in cooperation with the valve spring and the hydraulic lash adjuster, and an exhaust port for switching the communication state with the combustion chamber as the exhaust valve is opened and closed. In a multi-cylinder internal combustion engine having an exhaust manifold connected to the exhaust downstream side of these exhaust ports, a variable valve mechanism that makes the opening timing of the exhaust valve variable, and an exhaust valve calculated based on the engine operating state Control means for controlling the variable valve mechanism according to the target valve opening timing, and the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure Correction means for correcting the valve opening timing of the exhaust valve to be retarded from the target valve opening timing when it is estimated that the hydraulic lash adjuster is supplied from an engine-driven oil pump Driven by the pressure of the oil, provided with a water temperature detection means for detecting the temperature of the engine cooling water, the correction means includes a pressure detection means for detecting the pressure of the intake air of the internal combustion engine, the pressure detection means When the detected intake air pressure is equal to or higher than a predetermined pressure, it is estimated that the internal pressure of the exhaust manifold is equal to or higher than the predetermined pressure, and when the temperature of the engine cooling water detected by the water temperature detecting means is high, the predetermined pressure is lower than when it is low. The gist is to set the pressure to a large value.
According to the configurations of claims 5 to 7, when the variable valve mechanism is controlled according to the target valve opening timing and the exhaust pressure becomes excessively high, the valve opening timing of the exhaust valve is set to the target valve opening timing. Therefore, the exhaust valve is opened after the pressure in the cylinder becomes lower than in the case where such a retardation correction is not performed. As a result, the pressure of the exhaust gas discharged from the cylinder becomes low, and the exhaust pressure can be prevented from becoming excessively high. As a result, the force based on the pressure of the exhaust acting on the exhaust valve of the other cylinder in the direction of opening the valve and the pressing force of the hydraulic lash adjuster acting on the exhaust valve in the direction of opening the valve. The resultant force can be prevented from becoming larger than the urging force of the valve spring acting in the direction of closing the valve with respect to the exhaust valve, and the occurrence of pump-up of the hydraulic lash adjuster can be suppressed. Become. Therefore, it is possible to suppress the occurrence of poor seating of the exhaust valve due to excessive increase in the exhaust pressure while suppressing the increase in engine resistance due to the opening / closing drive of the exhaust valve.
Further, since the internal pressure of the exhaust manifold can be estimated by grasping the pressure of the intake air, the internal pressure of the exhaust manifold is increased when the intake air pressure is equal to or higher than a predetermined pressure, as in the configuration according to claims 5 to 7. If it is estimated that the pressure is equal to or higher than the predetermined pressure, it is possible to determine whether or not to correct the exhaust valve opening timing to the retard side from the target valve opening timing without directly detecting the internal pressure of the exhaust manifold. Will be able to.
Further, assuming that the predetermined pressure for determining whether or not to correct the opening timing of the exhaust valve to be retarded from the target valve opening timing is a constant value, for example, the pressing force of the hydraulic lash adjuster is assumed in advance. When the pressure is larger than the above, the hydraulic lash adjuster is pumped up even though the internal pressure of the exhaust manifold is smaller than the predetermined pressure, resulting in poor seating of the exhaust valve. On the other hand, in a hydraulic lash adjuster driven by the pressure of oil supplied from an engine-driven oil pump, the oil pressure is higher when the engine speed is high than when it is low. The pressing force of the adjuster increases. In view of the above, if the predetermined pressure is set to a smaller value when the engine speed is high than when it is low, the pressing force of the hydraulic lash adjuster can be increased. When the pressure is large, the predetermined pressure can be set to a smaller value than when the pressure is small, and the predetermined pressure can be accurately set according to the pressing force of the hydraulic lash adjuster. Therefore, although the internal pressure of the exhaust manifold is smaller than the predetermined pressure, it is possible to prevent the hydraulic lash adjuster from being pumped up, and to suppress the occurrence of poor seating of the exhaust valve. It becomes like this.
Then, assuming that the predetermined pressure for determining whether or not the opening timing of the exhaust valve is corrected to the retard side with respect to the target opening timing is a constant value, for example, the pressing force of the hydraulic lash adjuster is assumed in advance. When the pressure is larger than the above, the hydraulic lash adjuster is pumped up even though the internal pressure of the exhaust manifold is smaller than the predetermined pressure, resulting in poor seating of the exhaust valve. On the other hand, in a hydraulic lash adjuster driven by the pressure of oil supplied from an engine-driven oil pump, the viscosity and viscosity of the oil is lower when the oil temperature is higher than when the oil temperature is low. Since the amount of oil leaking from the tank increases, the pressing force of the lash adjuster decreases. In view of the above, if the predetermined pressure is set to a larger value when the temperature of the oil is high than when the temperature is low, the pressing force of the hydraulic lash adjuster can be increased. When the pressure is small, the predetermined pressure can be set to a larger value than when it is large, and the predetermined pressure can be accurately set according to the pressing force of the hydraulic lash adjuster. Therefore, although the internal pressure of the exhaust manifold is smaller than the predetermined pressure, it is possible to prevent the hydraulic lash adjuster from being pumped up, and to suppress the occurrence of poor seating of the exhaust valve. It becomes like this.
Furthermore, when the predetermined pressure for determining whether or not the valve opening timing of the exhaust valve is corrected to the retard side from the target valve opening timing is a constant value, for example, the pressing force of the hydraulic lash adjuster is assumed in advance. When the pressure is larger than the above, the hydraulic lash adjuster is pumped up even though the internal pressure of the exhaust manifold is smaller than the predetermined pressure, resulting in poor seating of the exhaust valve. On the other hand, in a hydraulic lash adjuster driven by the pressure of oil supplied from an engine-driven oil pump, the viscosity and viscosity of the oil is lower when the oil temperature is higher than when the oil temperature is low. Since the amount of oil leaking from the tank increases, the pressing force of the lash adjuster decreases. On the other hand, the temperature of the oil can be estimated by grasping the temperature of the engine cooling water. In view of the above, if the predetermined pressure is set to a larger value when the temperature of the engine cooling water is higher than when it is low as in the configuration described in claim 7, the hydraulic lash adjuster When the pressing force is small, the predetermined pressure can be set to a larger value than when it is large, and the predetermined pressure can be accurately set according to the pressing force of the hydraulic lash adjuster. Therefore, although the internal pressure of the exhaust manifold is smaller than the predetermined pressure, it is possible to prevent the hydraulic lash adjuster from being pumped up, and to suppress the occurrence of poor seating of the exhaust valve. It becomes like this.

The invention according to claim 8 is the multi-cylinder internal combustion engine according to any one of claims 1 to 7 , further comprising a supercharger that supercharges the air sucked into the combustion chamber by the exhaust pressure. It is a summary.

  In a multi-cylinder internal combustion engine equipped with a supercharger that supercharges air sucked into the combustion chamber by exhaust pressure, an exhaust valve caused by excessively high exhaust pressure as compared with those not equipped with the same The occurrence of poor seating cannot be ignored.

  In this regard, according to the above configuration, the pressure of the exhaust gas discharged from the cylinder is reduced, and it is possible to suppress the exhaust pressure from becoming excessively high. Therefore, it is possible to suppress the occurrence of poor seating of the exhaust valve due to the exhaust pressure while suppressing an increase in engine resistance due to the opening / closing drive of the exhaust valve.

<First Embodiment>
1 to 8, a first embodiment in which a multi-cylinder internal combustion engine according to the present invention is embodied as an in-cylinder in-cylinder injection gasoline engine (hereinafter referred to as “engine 10”) will be described.

FIG. 1 shows a schematic configuration of the engine 10.
A combustion chamber 11 is formed in each of the cylinders # 1 to # 4 of the engine 10, and an injector 12 that directly injects fuel into each combustion chamber 11, and a mixture of fuel and air injected by the injector 12 A spark plug 13 for igniting each is provided. An intake passage 20 and an exhaust passage 30 are connected to each combustion chamber 11 of the engine 10. In addition, the cylinders # 1 to # 4 of the engine 10 switch the communication state between the intake valve 21 and the combustion chamber 11 and the exhaust passage 30 for switching the communication state between the combustion chambers 11 and the intake passage 20. Each exhaust valve 31 is provided.

  The intake passage 20 has an intake port 22 connected to the combustion chamber 11 of each cylinder # 1 to # 4, an intake manifold 23 connected to the intake upstream side of the intake port 22, and an intake upstream side of the intake manifold 23. An intake pipe 24 to be connected is provided. The intake pipe 24 is provided with a throttle valve 25a and a throttle motor 25b that opens and closes the throttle valve 25. The flow rate of the intake air supplied to the combustion chamber 11 through the intake passage 20 depends on the opening of the throttle valve 25a. Be controlled.

  The exhaust passage 30 has an exhaust port 32 connected to the combustion chamber 11 of each cylinder # 1 to # 4, an exhaust manifold 33 connected to the exhaust downstream side of the exhaust port 32, and an exhaust downstream side of the exhaust manifold 33. An exhaust pipe 34 to be connected is provided.

Here, with reference to FIG. 2, a specific configuration of the exhaust valve 31 and a valve mechanism that opens and closes the exhaust valve 31 will be described in detail.
A retainer 311 is attached to the exhaust valve 31, and a valve spring 312 is provided between the retainer 311 and the cylinder head 14 of the engine 10. By this valve spring 312, the exhaust valve 31 is constantly urged in a direction to close the valve 31.

  The valve mechanism that opens and closes the exhaust valve 31 is a pivot type valve mechanism that is fixed to the camshaft 313 to which the rotation of the crankshaft (not shown) of the engine 10 is transmitted. A cam 314 and a rocker arm 315 driven along with the rotation of the cam 314 are provided. Among these, the rocker arm 315 is supported at one end (right end in the figure) by a hydraulic lash adjuster (hereinafter simply referred to as “lash adjuster 320”) provided on the cylinder head 14, and the other end (left end in the figure). Is in contact with the proximal end portion 31 a of the exhaust valve 31. That is, the lash adjuster 320 adjusts the position of the valve 31 by pressing the valve 31 in the opening direction of the exhaust valve 31. The rocker arm 315 is rotatably supported by a roller 316 that contacts the cam 314. When the roller 316 is pressed by the rotating cam 314, the rocker arm 315 swings with the other end supported by the lash adjuster 320 as a fulcrum, and the base end portion 31a of the exhaust valve 31 is thereby swung. It comes to be pressed. Thus, the exhaust valve 31 is driven to open and close by reciprocating in the axial direction thereof. The exhaust valve 31 is brought into a closed state by contacting the valve seat 17 provided in the cylinder head 14.

  Further, the engine 10 is provided with an oil pump 15 that is driven by transmission of rotation of the crankshaft. Oil discharged from the oil pump 15 is supplied to the lash adjuster 320 through the oil passage 16. .

  Further, the engine 10 is provided with a variable valve mechanism 40 that continuously changes the valve timing of the exhaust valve 31 by changing the rotational phase of the camshaft 313 relative to the rotational phase of the crankshaft.

Next, a specific configuration of the lash adjuster 320 will be described in detail with reference to FIG.
The lash adjuster 320 includes a bottomed cylindrical body 321, and a plunger 322, a plunger spring 323, a check ball 324, a check ball spring 325, and a ball retainer 326 are provided inside the body 321. A space between the inner bottom surface of the body 321 and the base end portion of the plunger 322 facing the body 321 is defined as a high pressure chamber 327, and the interior of the plunger 322 is defined as a low pressure chamber 328. The high-pressure chamber 327 and the low-pressure chamber 328 communicate with each other via a communication path 329 formed at the base end portion of the plunger 322. Oil holes 330 and 331 are formed in the body 321 and the plunger 322, respectively, and oil supplied from the oil pump 15 through the oil passage 16 is supplied to the low pressure chamber 328 through these oil holes 330 and 331. The high pressure chamber 327 is also filled with oil.

  The high-pressure chamber 327 is provided with a plunger spring 323 and a ball retainer 326, and the urging force of the plunger spring 323 acts on the plunger 322 via the ball retainer 326 so that the plunger 322 protrudes from the body 321 (see FIG. It is always energized in the middle-up direction). In the high pressure chamber 327, a check ball 324 and a check ball spring 325 are provided between the base end portion of the plunger 322 and the ball retainer 326 facing the plunger 322, and the urging force of the check ball spring 325 is the check ball. By acting on 324, the check ball 324 is held at a position where the communication path 329 is blocked.

  Accordingly, after the exhaust valve 31 starts to close, if the cam 314 tries to move away from the rocker arm 315, more precisely, if the cam 314 tries to move away from the roller 316, the plunger spring 323 extends and the plunger 322 moves away from the body 321. The rocker arm 315 is pressed against the cam 314 by the plunger 322. In this way, the rocker arm 315 is displaced following the cam 314, so that the occurrence of a clearance between the rocker arm 315 and the cam 314 is suppressed.

  When the plunger 322 advances from the body 321 in this way, the pressure of the high-pressure chamber 327 decreases as the volume of the high-pressure chamber 327 increases, and a force based on the pressure difference between the high-pressure chamber 327 and the low-pressure chamber 328 acts on the check ball 324. To come. Then, when the check ball 324 is displaced to a position where the blocking of the communication path 329 is released against the urging force of the check ball spring 325 by the force based on the pressure difference, oil flows from the low pressure chamber 328 to the high pressure chamber 327. become. After that, when the magnitude of the force based on the pressure difference falls below the urging force of the check ball spring 325, the check ball 324 is returned to a position where the communication path 329 is blocked.

  On the other hand, when the cam 314 attempts to push the rocker arm 315 after the exhaust valve 31 starts to open, the force at that time is transmitted to the plunger 322 via the rocker arm 315, and the plunger 322 attempts to enter the body 321. However, at this time, since the communication path 329 is blocked by the check ball 324, the oil flow from the high pressure chamber 327 to the low pressure chamber 328 is prohibited. The oil filled in the high-pressure chamber 327 prohibits the movement of the plunger 322 in the direction of reducing the volume of the high-pressure chamber 327, that is, the entry of the plunger 322 into the body 321.

  When the plunger 322 attempts to enter the body 321 in this way, a little oil in the high pressure chamber 327 passes through the gap between the inner peripheral surface of the body 321 and the outer peripheral surface of the plunger 322, and the lash adjuster 320 Due to leakage to the outside, such leakage causes the plunger 322 to sink slightly into the body 321. However, even if the plunger 322 enters the body 321 in this way, the plunger 322 returns to the original state through the operation of the lash adjuster 320 after the exhaust valve 31 starts to close. As described above, in the lash adjuster 320, oil is supplied into the body 321 as the exhaust valve 31 is opened and closed, and the oil enters the body 321 of the plunger 322 after the exhaust valve 31 starts to open. Entry is prohibited.

Further, the intake valve 21 and its valve mechanism are basically the same as the exhaust valve 31 and its valve mechanism, and therefore their explanation is omitted.
As shown in FIG. 1, the engine 10 is provided with a supercharger 50 that is driven by the pressure of exhaust discharged from the combustion chamber 11. The supercharger 50 includes a turbine 51 provided in the exhaust pipe 34 and a compressor 52 provided in the intake pipe 24 and axially connected to the turbine 51. When the turbine 51 is rotated by the exhaust pressure, the compressor 52 that is axially connected to the turbine 51 is rotated accordingly, whereby the air sucked into the combustion chamber 11 is supercharged.

  Further, the engine 10 is provided with various sensors for detecting the operating state. That is, in order to calculate the rotational speed of the engine 10 (hereinafter referred to as “engine rotational speed NE”), the crank angle sensor 61 that detects the rotational phase of the crankshaft and the opening of the throttle valve 25a (hereinafter referred to as “throttle opening TA”). ) And an air flow meter 63 for detecting the flow rate of intake air passing through the intake pipe 24 (hereinafter referred to as “intake amount GA”). Further, a water temperature sensor 64 for detecting the temperature of the engine cooling water (hereinafter referred to as “engine cooling water temperature THW”), and a supercharging pressure for detecting the pressure of intake air (hereinafter referred to as “supercharging pressure PM”) on the intake downstream side of the compressor 52. A sensor 65 and a cam angle sensor 66 for detecting the rotational phase of the camshaft 313 are provided. Detection signals of these sensors 61 to 66 are input to an electronic control unit 70 that executes various controls of the engine 10.

  The electronic control device 60 includes a program for executing various controls, a calculation map, a memory for storing various data calculated when the control is executed, and the like. For example, the following controls are executed based on the engine operating state and the like ascertained from the output values of various sensors including the first. That is, the target injection amount and the target injection timing are calculated based on the engine operating state, the fuel injection control for controlling the injector 12 according to the target injection amount and the target injection timing, and the target ignition timing based on the engine operating state. The ignition timing control is performed to calculate and control the spark plug 13 according to the target ignition timing. Incidentally, in this embodiment, ignition is performed in the order of the first cylinder # 1, the third cylinder # 3, the fourth cylinder, and the second cylinder. Further, the target throttle opening is calculated based on the engine operating state, the intake air amount control for controlling the throttle motor 25b according to the target throttle opening, and the target valve timing of the exhaust valve 31 is calculated based on the engine operating state. Then, various controls such as a valve timing control for controlling the variable valve mechanism 40 according to the target valve timing are executed.

<Valve timing control>
The valve timing control of the exhaust valve 31 will be described with reference to FIG. This figure shows a lift curve which is a transition of the lift amount of the exhaust valve 31. Moreover, the alternate long and short dash line in the figure indicates the lift curve of the intake valve 21.

First, the electronic control unit 70 calculates a target valve timing VTBex that is a control target value of the valve timing of the exhaust valve 31 based on the engine operating state. Then, the variable valve mechanism 40 is driven so that the actual valve timing VTex of the exhaust valve 31 detected by the cam angle sensor 66 becomes the calculated target valve timing VTBex. In the present embodiment, the valve timing of the exhaust valve 31 is represented by using the retard amount VTex. That is, the valve timing VTex of the exhaust valve 31 is based on the most advanced angle position where the opening and closing of the exhaust valve 31 becomes the fastest in the valve timing change range by the variable valve mechanism 40 from the most advanced angle position. that it is represented using the amount of delay [° CA].

  By the way, in the engine 10 provided with the supercharger 50 as in the present embodiment, the pressure of the exhaust gas may become excessively high. In this case, the following problem occurs. That is, as described above, a force based on the exhaust pressure acts on the exhaust valve 31 in the direction in which the valve 31 is opened, and the pressing force of the lash adjuster 320 also acts in the direction in which the valve 31 is opened. Further, the urging force of the valve spring 312 acts on the exhaust valve 31 in the direction in which the valve 31 is closed. Here, when the exhaust pressure becomes excessively large and the resultant force of the force based on the exhaust pressure and the pressing force of the lash adjuster 320 becomes larger than the urging force of the valve spring 312, as shown in FIG. The plunger 322 of the lash adjuster 320 advances from the body 321, and as described above, oil flows from the low pressure chamber 328 to the high pressure chamber 327 as the volume of the high pressure chamber 327 increases (see FIG. 3). The adjuster 320 will be pumped up. As a result, a seating failure such that the exhaust valve 31 cannot be seated stably on the valve seat 17 occurs.

  To deal with such a problem, it is conceivable to employ a valve spring 312 having a larger spring coefficient in order to increase the urging force of the valve spring 312. In this case, however, the engine resistance accompanying the opening / closing drive of the exhaust valve 31 increases. A new problem will occur.

Therefore, when it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA, the valve opening timing of the target valve timing VTBex of the exhaust valve 31 calculated based on the engine operating state (hereinafter referred to as “target valve opening”). reduce the valve opening timing of the valve timing of the exhaust valve 31 than the timing "), i.e., a reduction of generation of the problems described above by executing the retarded angle compensation control for correcting the valve opening timing of the exhaust valve 31 retarded I am doing so.

Here, when it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA, the delay angle correction control is executed to set the valve opening timing of the exhaust valve 31 to the valve opening timing (hereinafter referred to as the target valve timing). , to explain the reason that correct complement to the retard side than the "target opening timing"). That is, when the variable valve mechanism 40 is controlled according to the target valve opening timing and the exhaust pressure becomes excessively high, if the valve opening timing of the exhaust valve 31 is corrected to the retard side with respect to the target valve opening timing, The exhaust valve 31 is opened after the pressure in the cylinder becomes lower than in the case where such retard correction control is not performed. As a result, the pressure of the exhaust discharged from the cylinder is reduced, and the exhaust pressure is prevented from becoming excessively high. As a result, the force based on the pressure of the exhaust acting on the exhaust valve 31 of the other cylinder in the direction of opening the valve 31 and the pushing of the lash adjuster 320 acting on the exhaust valve 31 in the direction of opening the valve 31. It is suppressed that the resultant force with the pressure becomes larger than the urging force of the valve spring 312 that acts on the exhaust valve 31 in the direction of closing the valve 31.

  In the retard correction control of the present embodiment, it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA when the supercharging pressure PM is equal to or higher than the predetermined pressure PMA.

<Delay correction control>
The retard angle correction control of the exhaust valve 31 will be described with reference to FIGS. FIG. 6 is a flowchart showing the processing procedure for retard correction control. A series of processing shown in this flowchart is repeatedly executed by the electronic control unit 70 during operation of the engine 10. FIG. 7 is a map that defines the relationship between the supercharging pressure PM and the retardation correction amount ΔVTex.

  In this process, first, the engine rotational speed NE and the engine load KL are read as the engine operating state at that time, and the basic retardation amount VTBex is calculated based on them (step S101). Here, for example, when the engine speed NE is low and the engine load KL is low, or when the engine speed NE is high and the engine load KL is high, the basic retardation amount VTBex is set to a small value. When the engine load KL is medium or when the engine load is high but the engine speed NE is low or medium, the basic retardation amount VTBex is set to a large value. In the present embodiment, as the engine load KL, a ratio “GA / GAmax” between the intake air amount GA at that time and the maximum intake air amount GAmax that is the maximum value of the intake air amount obtained at the engine rotational speed NE at that time. Used.

  Next, the supercharging pressure PM at that time is read, and the retardation correction amount ΔVTex is derived with reference to the map shown in FIG. 7 (step S102). In this map, when the supercharging pressure PM is lower than the predetermined pressure PMA, the retard correction amount ΔVTex is set to “0”, and when the supercharging pressure PM is equal to or higher than the predetermined pressure PMA, the retard correction is performed as the supercharging pressure PM becomes higher. The amount ΔVTex is set to be large.

Once the basic retardation amount VTBex and the retardation correction amount ΔVTex are derived in this way, the final retardation amount VTTex is calculated based on the following equation (1) (step S103), and this process is temporarily terminated.
VTTex ← VTBex + ΔVTex (1)
Next, referring to the upper part of the timing chart of FIG. 8, (a) transition of the lift amount of the exhaust valve 31 of the first cylinder # 1 and (b) third when the retardation correction control is not executed. An example of transition of the lift amount of the exhaust valve 31 of the cylinder # 3 and (c) transition of the internal pressure PE of the exhaust manifold 33 will be described. In addition, the dashed-dotted line in a figure has shown the lift curve of the intake valve 21 in a corresponding cylinder.

  When the supercharging pressure PM is equal to or higher than the predetermined pressure PMA, when the retardation correction control is not executed, the exhaust valve 31 of the first cylinder # 1 is opened at the timing t1 based on the basic retardation amount VTBex. The valve is closed at timing t5 (FIG. 8A). On the other hand, at timing t5, the exhaust valve 31 of the third cylinder # 3 is opened at timing t5 based on the basic retardation amount VTBex by the valve timing based on the basic retardation amount VTBex (FIG. 8B). . As the exhaust is discharged from the third cylinder # 3, the internal pressure PE of the exhaust manifold 33 temporarily rises from the base value PE1 to the peak value PE2 at timing t6 (FIG. 8 (c)). At this time, in the exhaust valve 31 of the first cylinder # 1 to be closed after timing t5, the internal pressure PE of the exhaust manifold 33 becomes equal to or higher than the predetermined pressure PEA, so that the force based on the exhaust pressure and the lash adjuster The resultant force with the pressing force of 320 is larger than the urging force of the valve spring 312. As a result, the lash adjuster 320 is pumped up, and the seating failure of the exhaust valve 31 occurs.

  Next, referring to the lower part of the timing chart of FIG. 8, (d) the transition of the lift amount of the exhaust valve 31 of the first cylinder # 1 in the case of executing the retardation correction control, (e) the first An example of transition of the lift amount of the exhaust valve 31 of the three cylinder # 3 and (f) transition of the internal pressure PE of the exhaust manifold 33 will be described. In addition, the dashed-dotted line in a figure has shown the lift curve of the intake valve 21 in a corresponding cylinder.

When the supercharging pressure PM is equal to or higher than the predetermined pressure PMA, when the retardation correction control is executed, the exhaust valve 31 of the first cylinder # 1 opens at timing t2 based on the final retardation amount VTTex. Then, the valve is closed at timing t6 (FIG. 8 ( d )). On the other hand, the exhaust valve 31 of the third cylinder # 3 is opened at timing t6 based on the final retard amount VTTex (FIG. 8 ( e )). As the exhaust gas is discharged from the third cylinder # 3, the internal pressure PE of the exhaust manifold 33 increases from the base value PE3 to the peak value PE4 at time t7 (FIG. 8 (f )). At this time, paying attention to the third cylinder # 3, the exhaust valve 31 is opened after the pressure in the cylinder becomes lower as compared with the case where the retardation correction control is not executed. The peak value PE4 of the internal pressure PEM of the exhaust manifold 33 at t7 is less than the predetermined pressure PEA . For this reason, in the first cylinder # 1 of the exhaust valve 31 to be closed in the subsequent timing t6, the resultant force of the pressing force of the force and the lash adjuster 320 based on the pressure of the exhaust, than the urging force of the valve spring 312 It will never grow. As a result, the pump up of the lash adjuster 320 does not occur, and the seating failure of the exhaust valve 31 does not occur.

According to the multi-cylinder internal combustion engine according to the present embodiment described above, the following effects can be obtained.
(1) The variable valve mechanism 40 that makes the opening timing of the exhaust valve 31 variable is provided, and when it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA, the opening timing of the exhaust valve 31 is set. Therefore, the retard correction control for correcting the retard to the retard side with respect to the target valve opening timing calculated based on the engine operating state is executed. Therefore, it is possible to suppress the occurrence of poor seating of the exhaust valve 31 due to the excessive increase in the exhaust pressure while suppressing the increase in engine resistance due to the opening / closing drive of the exhaust valve 31. Become.

  (2) When the supercharging pressure PM detected by the supercharging pressure sensor 65 is equal to or higher than the predetermined pressure PMA, it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA. As a result, it is possible to determine whether or not to correct the valve opening timing of the exhaust valve 31 to be retarded from the target valve opening timing without directly detecting the internal pressure PE of the exhaust manifold 33.

  (3) When the boost pressure PM is high, the delay angle correction amount ΔVTex of the valve opening timing of the exhaust valve 31 is set to a larger value than when it is low. Thus, even when the exhaust valve pressure is increased when the variable valve mechanism 40 is controlled according to the target valve opening timing, the retardation correction amount ΔVTex is set according to the degree, so that the cylinder After the internal pressure becomes sufficiently low, the exhaust valve 31 is opened. Thereby, the pressure of the exhaust gas discharged from the cylinder can be accurately reduced. Therefore, the occurrence of pump-up of the lash adjuster 320 can be accurately suppressed.

Second Embodiment
A second embodiment of the multi-cylinder internal combustion engine according to the present invention will be described with reference to FIG.
In the first embodiment, the predetermined pressure PMA for determining whether or not to execute the retardation correction control is set to a constant value. In the present embodiment, when the engine speed NE is high, the predetermined pressure PMA is low. The predetermined pressure PMX is set to a small value compared to the above. Further, the predetermined pressure PMX is set to a larger value when the engine coolant temperature THW is high than when it is low.

The reason will be described below.
When the predetermined pressure PMA is a constant value regardless of the supercharging pressure PM, that is, when the predetermined pressure PMA is a constant value regardless of the internal pressure PE of the exhaust manifold 33, for example, when the pressing force of the lash adjuster 320 is larger than previously assumed Although the supercharging pressure PM is smaller than the predetermined pressure PMA, that is, although the internal pressure PE of the exhaust manifold 33 is smaller than the predetermined pressure PEA, the lash adjuster 320 is pumped up and the exhaust gas is exhausted. A poor seating of the valve 31 occurs.

On the other hand, in the lash adjuster 320 driven by the pressure of oil supplied from the engine-driven oil pump 15, when the engine speed NE is high, the oil pressure is higher than when the engine speed NE is low. The pressing force of 320 increases. In view of these, if the predetermined pressure PMX is set to a smaller value when the engine speed NE is high than when it is low, the predetermined pressure PMX is larger than when it is small when the pressing force of the lash adjuster 320 is large. now pressure PMX is set to a small value, ing as accurate setting of the predetermined pressure PMX corresponding to the pressing force of the lash adjuster 320 is achieved.

On the other hand, when the temperature of the oil is high, the viscosity and viscosity of the oil is lower than when the temperature is low, and the amount of oil leakage from the drive portion increases accordingly, so the pressing force of the lash adjuster 320 is reduced. Further, the oil temperature of the lash adjuster 320 can be estimated by grasping the engine coolant temperature THW. In view of the above, if the predetermined pressure PMX is set to a larger value when the engine coolant temperature THW is high than when it is low, the predetermined pressure PMX is higher than when the lash adjuster 320 is small. now pressure PMX is set to a large value, by accurate setting of the predetermined pressure PMX corresponding to the pressing force of the lash adjuster 320 is Ru been achieved Uninaru.

FIG. 9 is a map that defines the relationship among the engine speed NE, the engine coolant temperature THW, and the predetermined pressure PMX.
When the engine speed NE is high, the predetermined pressure PMX is smaller than when the engine speed NE is low. Further, when the engine coolant temperature THW is high, the predetermined pressure PMX is larger than when it is low.

According to the multi-cylinder internal combustion engine according to the present embodiment described above, the following effects can be obtained.
(1) The lash adjuster 320 is driven by the pressure of oil supplied from the oil pump 15 driven by the engine 10, and when the engine speed NE is high, the predetermined pressure PMX is smaller than when the engine speed NE is low. It was decided to set. Thereby, when the pressing force of the lash adjuster 320 is large, the predetermined pressure PMX can be set to a smaller value than when the pressing force is small, and the predetermined pressure PMX is accurately set according to the pressing force of the lash adjuster 320. Will be able to. Therefore, although the internal pressure PE of the exhaust manifold 33 is smaller than the predetermined pressure PEX, it is possible to prevent the lash adjuster 320 from being pumped up, and to prevent the exhaust valve 31 from being poorly seated. Will be able to.

  (2) The lash adjuster 320 is driven by the pressure of oil supplied from the oil pump 15 driven by the engine 10, and the predetermined pressure PMX is larger when the engine cooling water temperature THW is high than when it is low. It was decided to set. Thereby, when the pressing force of the lash adjuster 320 is small, the predetermined pressure PMX can be set to a larger value than when the pressing force is large, and the predetermined pressure PMX is accurately set according to the pressing force of the lash adjuster 320. Will be able to. Therefore, although the internal pressure of the exhaust manifold 33 is smaller than the predetermined pressure PEA, it is possible to prevent the lash adjuster 320 from being pumped up, and to prevent the exhaust valve 31 from being poorly seated. Will be able to.

The multi-cylinder internal combustion engine according to the present invention is not limited to the configuration exemplified in the above-described embodiment, and can be implemented as, for example, the following forms appropriately modified.
In the second embodiment, when the engine rotational speed NE is high, the predetermined pressure PMX is set to a smaller value than when it is low, and when the engine cooling water temperature THW is high, the predetermined pressure PMX is larger than when it is low. It is set to a value. However, for example, when the influence of the engine coolant temperature THW on the pressing force of the lash adjuster 320 can be ignored, the predetermined pressure PMX may be set to a constant value regardless of the engine coolant temperature THW. If the influence of the engine speed NE on the pressing force of the lash adjuster 320 can be ignored, the predetermined pressure PMX may be set to a constant value regardless of the engine speed NE.

  In the second embodiment, the temperature of the oil of the lash adjuster 320 is estimated based on the engine coolant temperature THW. However, an oil temperature detecting means for directly detecting the oil of the lash adjuster 320 is provided, and the oil temperature The predetermined pressure PMX may be set to a larger value when the temperature of the oil detected by the detection means is higher than when the oil temperature is low. Even in this case, the same effects as those of the second embodiment can be obtained.

  In each of the above embodiments, it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA when the boost pressure PM detected by the boost pressure sensor 65 is equal to or higher than the predetermined pressure PMA, MAX. However, instead of this, an exhaust pressure sensor that directly detects the internal pressure PE of the exhaust manifold 33 may be provided, and the retardation correction control may be executed based on the detection result of the sensor.

  In each of the above embodiments, the engine 10 including the supercharger 50 is illustrated, but the engine to which the present invention is applied is not limited thereto. Even if the engine is an engine that does not include such a supercharger, if the present invention is applied, the effect of the present invention can be achieved as long as the exhaust pressure becomes excessively high. I can. In this case, the intake pressure may be detected instead of the supercharging pressure PM.

As in the above-described embodiments, when the boost pressure PM is high, setting the retardation correction amount ΔVTex of the valve opening timing of the exhaust valve 31 to a larger value than when the boost pressure PM is low is sufficient to increase the pressure in the cylinder. It is desirable for the exhaust valve 31 to be opened after the temperature is lowered to accurately suppress the occurrence of pumping up of the lash adjuster 320. However, if it is possible to suppress occurrence of pump-up of the lash adjuster 320, and but it may also not thus the retard correction amount ΔVTex variably set. In short, what is necessary is that the valve opening timing of the exhaust valve 31 is corrected to the retard side with respect to the target valve opening timing when it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA.

In each of the above embodiments, when it is estimated that the internal pressure PE of the exhaust manifold 33 is equal to or higher than the predetermined pressure PEA, the valve opening timing of the exhaust valve 31 is later than the target valve opening timing calculated based on the engine operating state. Although an example of correction to the corner side is illustrated, the present invention is not limited to this. That is, when the engine speed NE is high, valve surging is likely to occur, and when such valve surging occurs, the urging force of the valve spring 312 acting on the exhaust valve 31 is temporarily reduced. For this reason, even in such a case, there is a possibility that the above-described poor seating may occur. Therefore, when the engine speed NE is equal to or higher than the predetermined speed NEA, the retard correction control for correcting the valve opening timing of the exhaust valve 31 to the retard side with respect to the target valve opening timing may be executed. Thus, exhaust gas when the valve surging occurs of the valve 31, run to lever the retard correction control to correct the valve opening timing of the exhaust valve 31 to the retard side of the target opening timing, such retard correction as compared with the case of controlling not run, the exhaust valve 31 is to be opened after the pressure in the cylinder becomes lower. As a result, the pressure of the exhaust gas discharged from the cylinder becomes low, and the exhaust pressure can be prevented from becoming excessively high. As a result, the occurrence of pump-up of the lash adjuster 320 can be suppressed. Therefore, it is possible to suppress the occurrence of poor seating of the exhaust valve 31 due to the excessive increase in the exhaust pressure while suppressing the increase in engine resistance due to the opening / closing drive of the exhaust valve 31. Become. Further, in this case, if the retard correction amount ΔVTex is set to a larger value when the engine speed NE is high than when it is low, even if the valve surging of the exhaust valve 31 occurs. Since the retard correction amount is set according to the above, the exhaust valve 31 is opened after the pressure in the cylinder becomes sufficiently low. Thereby, the pressure of the exhaust gas discharged from the cylinder can be accurately reduced. Therefore, the occurrence of pump-up of the lash adjuster 320 can be accurately suppressed.

  In each of the above embodiments, an in-cylinder in-cylinder injection gasoline engine has been illustrated. However, the multi-cylinder internal combustion engine of the present invention is not limited to this. For example, a port injection type in which fuel is injected from the intake port 22, for example. The present invention can also be applied to a gasoline engine. The present invention can also be applied to a diesel engine.

1 is a schematic diagram schematically showing a schematic configuration of a multi-cylinder internal combustion engine according to a first embodiment of the present invention. The schematic diagram which shows typically the exhaust valve and its valve operating mechanism in the embodiment. Sectional drawing which shows the cross-section of the lash adjuster in the embodiment. The schematic diagram which shows typically the effect | action of the exhaust valve and its valve operating mechanism in the embodiment. The graph which showed the lift curve of the exhaust valve in the embodiment. 6 is a flowchart showing a processing procedure of retardation correction control in the same embodiment. The map which prescribed | regulated the relationship between the supercharging pressure and retardation correction amount in the embodiment. In the case where the retardation correction control of the embodiment is not executed, (a) the transition of the lift amount of the exhaust valve of the first cylinder, (b) the transition of the lift amount of the exhaust valve of the third cylinder, (c) the exhaust manifold (D) Transition of the lift amount of the exhaust valve of the first cylinder, (e) Transition of the lift amount of the exhaust valve of the third cylinder, (f) Exhaust manifold The timing chart which shows an example of transition of the internal pressure of. The map which prescribed | regulated the relationship between engine rotational speed and engine cooling water temperature, and a predetermined pressure about the modification of the retard correction control in the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Combustion chamber, 12 ... Injector, 13 ... Spark plug, 14 ... Cylinder head, 15 ... Oil pump, 16 ... Oil passage, 17 ... Valve seat, 20 ... Intake passage, 21 ... Intake valve, 22 ... Intake port, 23 ... Intake manifold, 24 ... Intake pipe, 25a ... Throttle valve, 25b ... Throttle motor, 30 ... Exhaust passage, 31 ... Exhaust valve, 32 ... Exhaust port, 33 ... Exhaust manifold, 34 ... Exhaust pipe, 40 ... Variable valve mechanism, 50 ... supercharger, 51 ... turbine, 52 ... compressor, 61 ... crank angle sensor, 62 ... throttle sensor, 63 ... air flow meter, 64 ... water temperature sensor (water temperature detection means), 65 ... supercharging pressure Sensors (pressure detection means), 66 ... Cam sensors, 70 ... Electronic control device (control means, correction means), 311 ... Retainer, 3 2 ... Valve spring, 313 ... Cam shaft, 314 ... Cam, 315 ... Rocker arm, 316 ... Roller, 320 ... Rush adjuster, 321 ... Body, 322 ... Plunger, 323 ... Plunger spring, 324 ... Check ball, 325 ... Check ball spring 326 ... Ball retainer, 327 ... High pressure chamber, 328 ... Low pressure chamber, 329 ... Communication hole, 330 ... Oil hole, 331 ... Oil hole.

Claims (8)

A valve spring that biases the valve in the closing direction of the exhaust valve, a hydraulic lash adjuster that presses the valve in the opening direction of the exhaust valve to adjust the position of the valve, and the valve spring and the hydraulic lash adjuster And a cam for driving the exhaust valve to open and close and an exhaust port for switching the communication state with the combustion chamber when the exhaust valve is opened and closed are connected to the exhaust downstream side of the exhaust port. In a multi-cylinder internal combustion engine having an exhaust manifold
A variable valve mechanism that makes the opening timing of the exhaust valve variable;
Control means for controlling the variable valve mechanism according to the target valve opening timing of the exhaust valve calculated based on the engine operating state;
Correction means for correcting the valve opening timing of the exhaust valve to the retard side with respect to the target valve opening timing when it is estimated that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure ;
The correction means includes pressure detection means for detecting the pressure of the intake air of the internal combustion engine, and estimates that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure when the pressure of the intake air detected by the pressure detection means is equal to or higher than the predetermined pressure. The multi-cylinder internal combustion engine is characterized in that when the internal pressure of the exhaust manifold is high, the retardation correction amount of the opening timing of the exhaust valve is set to a larger value than when it is low . The multi-cylinder internal combustion engine according to claim 1 ,
The hydraulic lash adjuster is driven by the pressure of oil supplied from an engine-driven oil pump,
The multi-cylinder internal combustion engine, wherein the correction means sets the predetermined pressure to a smaller value when the engine speed is high than when the engine speed is low. The multi-cylinder internal combustion engine according to claim 1 ,
The hydraulic lash adjuster is driven by the pressure of oil supplied from an engine-driven oil pump,
Comprising oil temperature detecting means for detecting the temperature of the oil;
The multi-cylinder internal combustion engine, wherein the correction means sets the predetermined pressure to a larger value when the oil temperature detected by the oil temperature detection means is high than when the oil temperature is low. The multi-cylinder internal combustion engine according to claim 1 ,
The hydraulic lash adjuster is driven by the pressure of oil supplied from an engine-driven oil pump,
Equipped with water temperature detection means for detecting the temperature of engine cooling water,
The multi-cylinder internal combustion engine, wherein the correction means sets the predetermined pressure to a larger value when the temperature of the engine coolant detected by the water temperature detection means is high than when the temperature is low.   A valve spring that biases the valve in the closing direction of the exhaust valve, a hydraulic lash adjuster that presses the valve in the opening direction of the exhaust valve to adjust the position of the valve, and the valve spring and the hydraulic lash adjuster And a cam for driving the exhaust valve to open and close and an exhaust port for switching the communication state with the combustion chamber when the exhaust valve is opened and closed are connected to the exhaust downstream side of the exhaust port. In a multi-cylinder internal combustion engine having an exhaust manifold
  A variable valve mechanism that makes the opening timing of the exhaust valve variable;
  Control means for controlling the variable valve mechanism according to the target valve opening timing of the exhaust valve calculated based on the engine operating state;
  Correction means for correcting the valve opening timing of the exhaust valve to the retard side with respect to the target valve opening timing when it is estimated that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure;
  The hydraulic lash adjuster is driven by the pressure of oil supplied from an engine-driven oil pump,
  The correction means includes pressure detection means for detecting the pressure of the intake air of the internal combustion engine, and estimates that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure when the pressure of the intake air detected by the pressure detection means is equal to or higher than the predetermined pressure. When the engine speed is high, the predetermined pressure is set to a smaller value than when the engine speed is low.
  A multi-cylinder internal combustion engine.   A valve spring that biases the valve in the closing direction of the exhaust valve, a hydraulic lash adjuster that presses the valve in the opening direction of the exhaust valve to adjust the position of the valve, and the valve spring and the hydraulic lash adjuster And a cam for driving the exhaust valve to open and close and an exhaust port for switching the communication state with the combustion chamber when the exhaust valve is opened and closed are connected to the exhaust downstream side of the exhaust port. In a multi-cylinder internal combustion engine having an exhaust manifold
  A variable valve mechanism that makes the opening timing of the exhaust valve variable;
  Control means for controlling the variable valve mechanism according to the target valve opening timing of the exhaust valve calculated based on the engine operating state;
  Correction means for correcting the valve opening timing of the exhaust valve to the retard side with respect to the target valve opening timing when it is estimated that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure;
  The hydraulic lash adjuster is driven by the pressure of oil supplied from an engine-driven oil pump,
  Comprising oil temperature detecting means for detecting the temperature of the oil;
  The correction means includes pressure detection means for detecting the pressure of the intake air of the internal combustion engine, and estimates that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure when the pressure of the intake air detected by the pressure detection means is equal to or higher than the predetermined pressure. When the oil temperature detected by the oil temperature detecting means is high, the predetermined pressure is set to a larger value than when the oil temperature is low.
  A multi-cylinder internal combustion engine.   A valve spring that biases the valve in the closing direction of the exhaust valve, a hydraulic lash adjuster that presses the valve in the opening direction of the exhaust valve to adjust the position of the valve, and the valve spring and the hydraulic lash adjuster And a cam for driving the exhaust valve to open and close and an exhaust port for switching the communication state with the combustion chamber when the exhaust valve is opened and closed are connected to the exhaust downstream side of the exhaust port. In a multi-cylinder internal combustion engine having an exhaust manifold
  A variable valve mechanism that makes the opening timing of the exhaust valve variable;
  Control means for controlling the variable valve mechanism according to the target valve opening timing of the exhaust valve calculated based on the engine operating state;
  Correction means for correcting the valve opening timing of the exhaust valve to the retard side with respect to the target valve opening timing when it is estimated that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure;
  The hydraulic lash adjuster is driven by the pressure of oil supplied from an engine-driven oil pump,
  Equipped with water temperature detection means for detecting the temperature of engine cooling water,
  The correction means includes pressure detection means for detecting the pressure of the intake air of the internal combustion engine, and estimates that the internal pressure of the exhaust manifold is equal to or higher than a predetermined pressure when the pressure of the intake air detected by the pressure detection means is equal to or higher than the predetermined pressure. When the temperature of the engine cooling water detected by the water temperature detecting means is high, the predetermined pressure is set to a larger value than when the temperature is low.
  A multi-cylinder internal combustion engine. The multi-cylinder internal combustion engine according to any one of claims 1 to 7 ,
A multi-cylinder internal combustion engine comprising a supercharger that supercharges air sucked into a combustion chamber by exhaust pressure.

Images