JP2011236803A - Internal combustion engine control apparatus with variable compression ration mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the possibility that a catalyst device of an engine exhaust system is melted during a transient state of a compression ratio where a mechanical compression ratio is gradually increased by the variable compression ratio mechanism due to changes of an operation state from a high engine load into at a low engine load in an internal combustion engine control apparatus with a variable compression mechanism for varying a mechanical compression ratio, including a first fuel injection valve where fuel is injected to an intake port by the internal combustion engine and a second fuel injection valve where the fuel is directly injected to a cylinder.SOLUTION: During the transient state of the compression state (t0-t1) where the mechanical compression ratio C is gradually increased, an injection amount ratio R between the first fuel injection valve and the second fuel injection valve is changed from the first injection amount ratio R1 suitable for an operation during the engine high load into the third injection amount ratio R3 that increases the fuel injection amount of the first fuel injection valve in comparison with the second injection ratio R2 suitable for an operation during the engine low load.

Description

  The present invention relates to a control device for an internal combustion engine including a variable compression ratio mechanism that makes a mechanical compression ratio variable.

  The mechanical compression ratio ((top dead center cylinder volume + stroke volume) / top dead center cylinder volume) is variable by changing the distance between the cylinder block and the crankshaft by relatively moving the cylinder block and the crankcase. An internal combustion engine having a variable compression ratio mechanism has been proposed.

  If the mechanical compression ratio is increased to increase the actual expansion ratio ((top dead center cylinder volume + stroke volume until exhaust valve opening) / top dead center cylinder volume), the thermal efficiency can be increased. As a result, in general, at a low engine load at which the thermal efficiency deteriorates as compared with a high engine load, the mechanical compression ratio is increased and the thermal efficiency is improved as compared to a high engine load.

  By the way, in an internal combustion engine having a first fuel injection valve for injecting fuel into the intake port and a second fuel injection valve for injecting fuel directly into the cylinder, an optimal injection amount ratio for each engine operating state Thus, fuel is injected from the first fuel injection valve and the second fuel injection valve.

  In the case where the internal combustion engine having the first and second fuel injection valves for each cylinder includes a variable compression ratio mechanism, the first fuel injection valve and the first fuel injection valve are arranged so that torque fluctuation does not occur when the mechanical compression ratio is changed. It has been proposed to control the injection amount ratio with the two fuel injection valves (see Patent Document 1).

JP2007-211637 JP2007-327399A

  The internal combustion engine described in Patent Document 1 suppresses a torque shock that occurs because the mechanical compression ratio is instantaneously changed. When the mechanical compression ratio is gradually changed, the torque shock is It does not occur and control of the injection rate is not required.

  However, if nothing is done in this way, the engine exhaust system is relatively hot due to engine high load operation when the engine compression ratio is gradually increased when the operating state changes from engine high load to engine low load. However, the catalyst device may be melted due to a further increase in temperature due to an inflow of unburned fuel in the exhaust gas that increases when the mechanical compression ratio is increased.

  Accordingly, an object of the present invention is a control device for an internal combustion engine that includes a variable compression ratio mechanism that makes a mechanical compression ratio variable, and the internal combustion engine directly injects fuel into the intake port and the first fuel injection valve. And a second fuel injection valve for injecting fuel, and the mechanical compression ratio is gradually increased by a variable compression ratio mechanism as the operating state changes from a high engine load to a low engine load It is to make it difficult for the catalyst device of the engine exhaust system to melt during a specific transient state.

  The control apparatus for an internal combustion engine provided with the variable compression ratio mechanism according to claim 1 of the present invention is a control apparatus for an internal combustion engine provided with a variable compression ratio mechanism that makes the mechanical compression ratio variable, wherein the internal combustion engine is an intake port. A first fuel injection valve for injecting fuel into the cylinder and a second fuel injection valve for injecting fuel directly into the cylinder, and with the change in the operating state from the engine high load to the engine low load, A compression ratio transient state in which the mechanical compression ratio is gradually increased from the first mechanical compression ratio suitable for operation at high engine load to the second mechanical compression ratio suitable for operation at low load by a variable compression ratio mechanism. Between the first fuel injection valve and the second fuel injection valve from the first injection amount ratio suitable for operation at high engine load to the second injection amount ratio suitable for operation at low engine load. In internal combustion engine control devices that gradually change the volume ratio During the compression ratio transient state, the injection amount ratio is changed from the first injection amount ratio to the third injection amount ratio that increases the fuel injection amount of the first fuel injection valve from the second injection amount ratio. It is characterized by being gradually changed.

  According to a second aspect of the present invention, there is provided a control apparatus for an internal combustion engine comprising the variable compression ratio mechanism according to the second aspect, wherein the mechanical compression ratio is the second mechanical compression. When the ratio is set, the third injection amount ratio is maintained for the set period.

  According to a third aspect of the present invention, there is provided a control device for an internal combustion engine having a variable compression ratio mechanism according to a third aspect of the present invention, wherein the control device for an internal combustion engine has a variable compression ratio mechanism according to the first or second aspect. The third injection amount ratio is changed so that the fuel injection amount of the first fuel injection valve increases as the temperature increases.

  When the internal combustion engine has a first fuel injection valve that injects fuel into the intake port and a second fuel injection valve that injects fuel directly into the cylinder, operation from a high engine load to a low engine load As the state changes, the compression ratio variable mechanism gradually increases the mechanical compression ratio from the first mechanical compression ratio suitable for operation at high engine load to the second mechanical compression ratio suitable for operation at low load. During the compression ratio transient state, the injection of the first fuel injection valve and the second fuel injection valve from the first injection amount ratio suitable for operation at high engine load to the second injection amount ratio suitable for operation at low engine load When the amount ratio is gradually changed, when the engine exhaust system temperature is relatively high due to the high engine load operation before the operating state change, the exhaust gas in the exhaust gas increases as the mechanical compression ratio increases. A large amount of unburned fuel flows into the catalytic device and burns It is possible to melting the catalytic converter the combustion heat is further increased the temperature of the catalyst device occurred. According to the control apparatus for an internal combustion engine comprising the compression ratio variable mechanism according to the first aspect of the present invention, the first injection amount suitable for operation at a high engine load is set during the compression ratio transient state. Since the ratio is gradually changed from the second injection amount ratio suitable for operation at low engine load to the third injection amount ratio that increases the fuel injection amount of the first fuel injection valve, the compression ratio is transient. In the meantime, even if the mechanical compression ratio is gradually increased, the fuel injected by the first fuel injection valve mixes better with the intake air than the fuel injected by the second fuel injection valve, thereby improving the homogeneity. It is possible to prevent the amount of unburned fuel in the exhaust gas from increasing so much that it is difficult to be discharged as unburned fuel. Can do.

  According to the control apparatus for an internal combustion engine having the compression ratio variable mechanism according to claim 2 of the present invention, the mechanical compression ratio is the second machine in the control apparatus for the internal combustion engine having the compression ratio variable mechanism according to claim 1. The injection amount ratio, which is the third injection amount ratio when the compression ratio is set, is maintained for the set period, and the unburned fuel in the exhaust gas is burned in the operation of the set period at the time of low engine load. The temperature of the catalyst device can also be lowered, and after the set period, the unburned fuel in the exhaust gas becomes relatively large due to the operation of the second injection ratio at the second mechanical compression ratio at the time of low engine load. Even if the combustion heat is generated, the temperature of the catalyst device is less likely to become so high that the catalyst device is melted, and the catalyst device can be made difficult to melt.

  According to the control apparatus for an internal combustion engine having the compression ratio variable mechanism according to claim 3 according to the present invention, in the control apparatus for the internal combustion engine having the compression ratio variable mechanism according to claim 1 or 2, the engine exhaust system catalyst The higher the temperature of the device, the higher the mechanical compression ratio during the compression ratio transient, and the greater the amount of unburned fuel in the exhaust gas, the more likely the catalyst device will melt due to combustion heat. The ratio is changed so that the fuel injection amount of the first fuel injection valve is increased, and an increase in unburned fuel in the exhaust gas is suppressed.

It is a schematic longitudinal cross-sectional view which shows the internal combustion engine controlled by the control apparatus of this invention. It is a figure for demonstrating the compression ratio variable mechanism of the internal combustion engine controlled by the control apparatus of this invention. It is a flowchart which shows control of the internal combustion engine by the control apparatus of this invention. It is a time chart which shows the change of the mechanical compression ratio when the driving | running state changes from the time of engine high load to the time of engine low load, the change of the injection quantity ratio, and the change of the temperature of a catalyst apparatus.

  FIG. 1 is a schematic longitudinal sectional view showing an internal combustion engine controlled by the control device of the present invention. In the figure, reference numeral 1 denotes an intake valve, and reference numeral 2 denotes an intake port communicating with the intake valve 1 into the cylinder. Reference numeral 3 denotes an exhaust valve, and reference numeral 4 denotes an exhaust port communicating with the inside of the cylinder via the exhaust valve 3. Reference numeral 5 denotes a first fuel injection valve that injects fuel into the intake port 2, and reference numeral 6 denotes a second fuel injection valve that injects fuel directly into the cylinder. The second fuel injection valve 6 is disposed, for example, on the intake valve side around the upper part of the cylinder. Reference numeral 7 denotes an ignition plug disposed substantially at the center of the cylinder upper portion, and 8 denotes a piston.

  As described above, the internal combustion engine having the first fuel injection valve 5 and the second fuel injection valve 6 has an optimum injection amount ratio for each engine operating state (engine load and engine speed) (mapped). ). The injection amount ratio R is, for example, an intake port injection amount ratio Q1 / Q, where Q1 is a fuel amount injected from the first fuel injection valve 5 into the intake port and indirectly supplied into the cylinder, Q2 Is the amount of fuel directly supplied from the second fuel injection valve 6 into the cylinder, and Q is the required amount of fuel Q = Q1 + Q2 in each engine operating state, for example, intake air so as to realize a desired air-fuel ratio Can be determined based on quantity.

  The fuel supplied from the intake port to the cylinder together with the intake air is more easily mixed with the intake air than the fuel directly injected into the cylinder and burns well, so that it is difficult to be discharged as unburned fuel. Further, the fuel directly injected into the cylinder has a larger latent heat of vaporization than the fuel supplied from the intake port to the cylinder together with the intake air, so that the in-cylinder temperature is further lowered, so that knocking is less likely to occur. Further, as the temperature in the vicinity of the injection hole of the second fuel injection valve 6 increases, deposits are more easily generated in the injection hole. Therefore, fuel is injected from the second fuel injection valve 6 to deposit deposits in the injection hole. Must be prevented. Considering these various reasons, an optimal injection amount ratio R is determined for each operating state. For example, the injection amount ratio R is reduced as the engine load increases, and the injection of the second fuel injection valve 6 is performed. The amount is increased.

  FIG. 2 is a view for explaining a compression ratio variable mechanism for moving the cylinder block relative to the crankcase in order to make the compression ratio of the internal combustion engine variable. In the figure, 100 is a cylinder block, 200 is a crankcase, and 300 is a piston at a compression top dead center position. The internal combustion engine is an in-line cylinder arrangement type.

  In the front view shown in FIG. 2, the first support 11 is provided on one side of the lower part of the cylinder block 100, the second support 12 is provided on the other side of the lower part of the cylinder block 100, and the upper part of the crankcase 200 is A third support 21 is provided on one side, and a fourth support 22 is provided on the other side of the upper portion of the crankcase 200. In the lowest position of the cylinder block 100 shown in FIG. 2A, concentric first holes and third holes are formed in the first support 11 and the third support 21, and the second support 12 and the fourth support 22 are formed in the second support 12 and the fourth support 22. Are formed with concentric second and fourth holes. The first hole, the second hole, the third hole, and the fourth hole have the same diameter, and the first hole and the second hole are symmetrical with respect to a vertical plane passing through the center of each cylinder, and the third hole And the fourth hole is symmetrical.

  A first boss 13, a second boss 14, a third boss, and a fourth boss are disposed in the first hole, the second hole, the third hole, and the fourth hole, respectively, so as to be rotatable. The first boss 13, the second boss 14, the third boss, and the fourth boss are formed with eccentric holes having the same diameter at the same position, and the eccentric hole of the first boss 13 and the eccentric hole of the third boss are rotated. The first shaft 15 is inserted as possible, and the second shaft 16 is rotatably inserted into the eccentric hole of the second boss 14 and the eccentric hole of the fourth boss.

  With the variable compression ratio mechanism configured as described above, at the lowest position (A) of the cylinder block 10, the first boss 13 (counterclockwise) and the second boss 14 (clockwise) are rotated 90 degrees in opposite directions. When moved, the cylinder block 100 moves up to the intermediate position (B) with respect to the crankcase 200. As a result, the top dead center cylinder volume is increased, and the mechanical compression ratio ((top dead center cylinder volume + stroke volume) / top dead center cylinder volume) is lowered as compared with the lowest position (A) of the cylinder block 100. be able to.

  Further, when the first boss 13 is rotated 90 degrees counterclockwise in FIG. 2 at the intermediate position (B) of the cylinder block 10, the second boss 14 is rotated 90 degrees clockwise in FIG. The cylinder block 100 is raised to the uppermost position (C) with respect to the crankcase 200. As a result, the top dead center cylinder volume is further increased, and the mechanical compression ratio ((top dead center cylinder volume + stroke volume) / top dead center cylinder volume) is lowered as compared with the intermediate position (B) of the cylinder block 100. be able to. Thus, the desired mechanical compression ratio can be realized by rotating the first boss 13 and the second boss 14 by an arbitrary angle in opposite directions.

  If the mechanical compression ratio is increased, the actual expansion ratio ((top dead center cylinder volume + stroke volume until exhaust valve opening) / top dead center cylinder volume) can be increased to increase thermal efficiency. In addition to such a variable compression ratio mechanism, if a variable valve timing mechanism that can change the closing timing of the intake valve and the opening timing of the exhaust valve is provided, the actual expansion for each mechanical compression ratio is provided. The ratio can be optimally controlled, and the actual compression ratio ((top dead center cylinder volume + stroke volume since intake valve closing) / top dead center cylinder volume) can also be optimally controlled. In this way, Atkinson cycle operation is also possible.

  An optimum mechanical compression ratio is determined for each engine operating state (mapped), and for example, the mechanical compression ratio C is lowered as the engine load increases. Thus, when the engine operating state changes from a high engine load to a low engine load due to a change in the amount of depression of the accelerator pedal, the compression ratio variable mechanism is operated to increase the mechanical compression ratio. At this time, the mechanical compression ratio cannot be instantaneously changed by the above-described variable compression ratio mechanism, and the mechanical compression ratio C is changed from the first mechanical compression ratio C1 suitable for high engine load operation before the change. The second mechanical compression ratio C2 suitable for low load operation is gradually increased for each cylinder.

  During the compression ratio transient state in which the mechanical compression ratio C gradually changes from the first mechanical compression ratio C1 to the second mechanical compression ratio C2 in this way, the injection amount ratio R is also normally high engine operation before the change. Is gradually increased from the first injection amount ratio R1 suitable for the second injection amount ratio R2 suitable for the engine low load operation after the change.

  However, when the exhaust gas temperature is high in the engine high load operation before the change, the catalyst device (supporting a noble metal catalyst or the like having an oxidation function) disposed in the engine exhaust system has a relatively high temperature. There may be. In particular, a small catalyst device disposed near the engine body to purify exhaust gas at the time of starting the engine tends to be hot. Thus, when the catalyst device is at a relatively high temperature, the ratio of the clevis volume in the combustion chamber increases as the mechanical compression ratio gradually increases, and the amount of unburned fuel discharged increases during combustion in each cylinder. Therefore, a relatively large amount of unburned fuel flows into the high temperature catalyst device and burns, and a relatively large amount of combustion heat is generated, which may cause the catalyst device to melt down by further increasing the temperature of the catalyst device. .

  The control device according to the present invention controls the injection amount ratio R of the first fuel injection valve 5 and the second fuel injection valve 6 according to the flowchart shown in FIG. 3 as an electronic control device, and makes it difficult to melt the catalyst device. . First, in step 101, it is determined whether or not the target change amount ΔC of the mechanical compression ratio C accompanying the change in the operating state from the high engine load to the low engine load is equal to or greater than the set amount A. The target change amount ΔC is a difference between the second mechanical compression ratio C2 suitable for the operation after the change and the first mechanical compression ratio C1 suitable for the operation before the change, and when the determination in step 101 is negative, Either the change in compression ratio is not required, the mechanical compression ratio is required to be lowered, or the engine compression ratio is required to be slightly increased. Since the control of the general injection amount ratio is performed, the process is finished as it is.

  On the other hand, when the determination in step 101 is affirmed, it is required to increase the mechanical compression ratio relatively large. At this time, in step 102, the injection amount ratio R2 suitable for the changed operation is determined. Next, in step 103, it is determined whether or not the temperature T (measured temperature or estimated temperature) of the catalyst device is equal to or higher than the set temperature T1. When this determination is denied, the catalyst device is not melted even by the control of the general injection amount ratio. For example, as a control of the general injection amount ratio, in step 104, the engine high load operation before the change is performed. The injection amount ratio R also changes while the mechanical compression ratio is gradually changed by the variable compression ratio mechanism from the first mechanical compression ratio C1 suitable for the engine to the second mechanical compression ratio C2 suitable for the engine low load operation after the change. Injection corresponding to the current mechanical compression ratio so as to be gradually changed from the first injection amount ratio R1 suitable for the previous engine high-load operation to the second injection amount ratio R2 suitable for the changed engine low-load operation. The amount ratio R is determined, and is set as the injection amount ratio of the cylinder that realizes the current mechanical compression ratio.

  Next, in step 105, it is determined whether or not the injection amount ratio R has become an injection amount ratio R2 suitable for engine low-load operation after the change. If this determination is negative, the injection amount ratio R is determined in step 104. If the determination is made and the determination in step 105 is affirmed, the mechanical compression ratio is set to the second mechanical compression ratio C2 suitable for the engine low load operation after the change, and the injection amount ratio is also suitable for the engine low load operation after the change. The second injection amount ratio R2 is set. In step 113, the injection amount ratio is maintained at the second injection amount ratio R2 suitable for the engine low load operation after the change, and the control is finished.

  On the other hand, when the determination in step 103 is affirmative, in step 106, the injection amount ratio R3 (third injection amount) at which the second mechanical compression ratio C2 suitable for engine low load operation after the mechanical compression ratio is changed is obtained. The ratio) is made larger by ΔR than the second injection amount ratio R2 suitable for engine low-load operation after the change. That is, the amount of fuel injected from the first fuel injection valve 5 into the intake port and indirectly supplied into the cylinder is increased.

  Next, in step 107, the mechanical compression ratio is gradually increased by the variable compression ratio mechanism from the first mechanical compression ratio C1 suitable for engine high load operation before the change to the second mechanical compression ratio C2 suitable for engine low load operation after the change. So that the injection amount ratio R is gradually changed from the first injection amount ratio R1 suitable for the engine high load operation before the change to the third injection amount ratio R3 determined in step 106. The injection amount ratio R corresponding to the current mechanical compression ratio is determined, and is set as the injection amount ratio of the cylinder that realizes the current mechanical compression ratio.

  Thus, when the temperature T of the catalyst device is relatively high, the mechanical compression ratio is suitable for operation at high engine load by the variable compression ratio mechanism as the operating state changes from high engine load to low engine load. During the compression ratio transient state that is gradually increased from the one mechanical compression ratio C1 to the second mechanical compression ratio C2 suitable for operation at low load, the injection amount ratio is changed to the operation at high engine load before the change. Gradually from the suitable first injection amount ratio R1 to the third injection amount ratio R3 that increases the fuel injection amount of the first fuel injection valve 5 from the second injection amount ratio R2 suitable for operation at a low engine load after the change. Therefore, even if the mechanical compression ratio is gradually increased during the compression ratio transient state, the fuel injected by the first fuel injection valve 5 is injected by the second fuel injection valve 6. Improves homogeneity by better mixing with intake air than fuel Therefore, it is difficult to discharge as unburned fuel, the amount of unburned fuel in the exhaust gas can be prevented from increasing so much, generation of a large amount of combustion heat is suppressed in the catalyst device, and the catalyst device is hardly melted down. be able to.

  Next, in step 108, it is determined whether or not the injection amount ratio R has become the third injection amount ratio R3. When this determination is negative, the injection amount ratio R is determined in step 107, and the determination in step 108 is performed. If the determination is affirmative, the mechanical compression ratio is the second mechanical compression ratio C2 suitable for engine low load operation after the change, the injection amount ratio is the third injection amount ratio R3, and in step 109, the injection amount ratio Is maintained at the third injection amount ratio R3.

  When the determination in step 108 is affirmative, the injection amount ratio R may be gradually decreased to the second injection amount ratio R2 suitable for engine low load operation after the change, but the engine compression ratio C is the second. When the desired low-load operation is started at the compression ratio C2, the temperature T of the catalyst device may still be high, and a large amount of unburned fuel is discharged with the injection ratio as the second injection ratio R2. If the temperature of the catalyst device rises due to combustion heat, it may melt. Thereby, in step 110, it is determined whether or not a set period (which may be the number of cycles or time) has elapsed since the second mechanical compression ratio C2 is realized. When this determination is negative, in step 109, The injection amount ratio is maintained at the third injection amount ratio R3.

  If the determination in step 110 is affirmative, the temperature T of the catalyst device can be lowered even if unburned fuel is burned in the low load operation for the set period, and the catalyst device will not be melted. In step 112, the injection amount ratio R is gradually decreased from the third injection amount ratio R3. In step 112, it is determined whether or not the injection amount ratio R has reached the second injection amount ratio R2 suitable for engine low load operation after the change. To be judged. When this determination is negative, in step 111, the injection amount ratio R is gradually decreased. If the determination in step 112 is affirmed, in step 113, the injection amount ratio is maintained at the second injection amount ratio R2 suitable for the engine low load operation after the change, and the control is ended.

  FIG. 4 is a time chart showing a change in the mechanical compression ratio C, a change in the injection amount ratio R, and a change in the temperature T of the catalyst device when the operating state changes from the high engine load to the low engine load. . At time t0, a change from operation at high engine load to operation at low engine load is required. Accordingly, the mechanical compression ratio C is gradually changed from the first mechanical compression ratio C1 suitable for engine high load operation before the change to the second mechanical compression ratio C2 suitable for engine low load operation after the change by the variable compression ratio mechanism. And the second mechanical compression ratio C2 is realized at time t1.

  In the general control of the injection amount ratio R, the injection amount ratio R is suitable for the engine low load operation after the change from the first injection amount ratio R1 suitable for the engine high load operation before the change, as indicated by a dotted line. The second injection amount ratio R2 is gradually changed, and at the time t1, the second mechanical compression ratio C2 is realized, and at the same time, the second injection amount ratio R2 is realized. In such control, when the temperature T of the catalyst device is relatively high, as shown by the dotted line, the discharge amount of unburned fuel increases as the mechanical compression ratio is increased. If the catalyst device burns in the catalyst device and generates a large amount of combustion heat, the catalyst device may become considerably hot and melt.

  On the other hand, in the flowchart shown in FIG. 3, the injection amount ratio R is suitable for the engine low load operation after the change from the first injection amount ratio R1 suitable for the engine high load operation before the change, as indicated by the solid line. The second injection amount ratio R3 is gradually changed to a third injection amount ratio R3, and at the time t1, the second mechanical compression ratio C2 is realized, and at the same time, the third injection amount ratio R3 is realized. Thereby, even when the temperature T of the catalyst device is relatively high, as shown by the solid line, if the injection amount ratio is increased and the amount of fuel injected by the first fuel injection valve 5 is increased, the first fuel The fuel injected by the injection valve 5 mixes better with the intake air than the fuel injected by the second fuel injection valve 6 and improves the homogeneity, so that it is difficult to be discharged as unburned fuel, and the mechanical compression ratio is increased. However, since the discharge amount of unburned fuel does not increase so much, the temperature of the catalytic device does not become so high as to melt.

  Furthermore, as shown by the solid line, if the third injection amount ratio R3 is maintained until time t2 and the discharge amount of unburned fuel is suppressed, it is not discharged in the engine low load operation from time t1 to t2. Since the temperature T of the catalyst device gradually decreases even when the fuel is burned, the injection amount ratio is gradually approached to the second injection amount ratio R2 suitable for engine low-load operation after the change from time t2, Even if the amount of discharged fuel increases, the temperature of the catalytic device does not increase so much.

  In step 106 of the flowchart of FIG. 3, ΔR added to the second injection amount ratio R2 to determine the third injection amount ratio R3 may be a constant value, but increases as the temperature T of the catalyst device increases. If the discharge amount of unburned fuel during the compression ratio transient state is reduced, the catalyst device can be more reliably prevented from melting.

2 Intake port 5 First fuel injection valve 6 Second fuel injection valve 100 Cylinder block 200 Crankcase 300 Piston

Claims (3)

  A control device for an internal combustion engine comprising a compression ratio variable mechanism that makes a mechanical compression ratio variable, wherein the internal combustion engine includes a first fuel injection valve that injects fuel into an intake port and a fuel that directly injects fuel into a cylinder. A first machine having two fuel injection valves and having a mechanical compression ratio suitable for operation at a high engine load by the variable compression ratio mechanism in accordance with a change in operation state from a high engine load to a low engine load During the compression ratio transient state, which is gradually increased from the compression ratio to the second mechanical compression ratio suitable for operation at the low load, the engine low ratio is determined from the first injection amount ratio suitable for the operation at the high engine load. In the control apparatus for an internal combustion engine that gradually changes the injection amount ratio of the first fuel injection valve and the second fuel injection valve to the second injection amount ratio suitable for operation at the time of load, during the compression ratio transient state, The injection amount ratio from the first injection amount ratio Control system for an internal combustion engine having a variable compression ratio mechanism, wherein the gradually changing into a third injection amount ratio to increase the serial fuel injection amount of the first fuel injection valve than the second injection amount ratio.   2. The internal combustion engine having a variable compression ratio mechanism according to claim 1, wherein when the mechanical compression ratio is the second mechanical compression ratio, the injection amount ratio that is the third injection amount ratio is maintained for a set period. Engine control device.   The third injection amount ratio is changed so that the fuel injection amount of the first fuel injection valve is increased as the temperature of the catalyst device of the engine exhaust system is higher. A control device for an internal combustion engine comprising a variable compression ratio mechanism.

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