JP4661477B2 - Internal combustion engine system - Google Patents

Description

  The present invention relates to an internal combustion engine system.

  Conventionally, for example, Japanese Patent No. 3018892 discloses a technique for increasing output speed of valve timing and ensuring output characteristics during acceleration of a vehicle as compared with normal operation.

Japanese Patent No. 3018892 JP 2002-371813 A JP 2000-257454 A Japanese Patent Laid-Open No. 10-331670 JP 11-210509 A

  However, in the above prior art, the valve timing operating speed in the catalyst warm-up process is not taken into consideration, and therefore it is not possible to optimally control the valve timing operating speed when shifting from the catalyst warm-up operation to the normal operation. Have difficulty.

  In particular, in the process of shifting from the catalyst warm-up process to the normal operation, the operating speed of the valve timing has a great influence on the combustion state.If the operating speed is not appropriate, the amount of residual gas in the cylinder changes, and the combustion state It will get worse. For this reason, problems such as deterioration of drivability and exhaust emission are caused.

  The present invention has been made to solve the above-described problems. When the catalyst warm-up operation is shifted to the normal operation, the operation speed of the valve timing is optimally controlled, whereby the operation of the internal combustion engine is performed. The purpose is to control the state optimally.

In order to achieve the above object, a first invention is an internal combustion engine system,
Variable valve operating means for varying the opening and closing timing of the exhaust valve;
When a catalyst warm-up request is issued, a catalyst warm-up operation is performed by changing the phase of the opening / closing timing to the retard side, and when the warm-up request is canceled, the phase of the opening / closing timing is changed. Catalyst warm-up means for shifting to the normal operation, which is variable to the advance side than that during the catalyst warm-up operation,
When migrating to the normal operation from the catalyst warm-up operation, the phase variable speed set based on the hydrocarbon content of the residual gas quantity and the exhaust of the cylinder, the speed for changing the phase of the opening and closing timing at a predetermined speed Setting means;
It is provided with.

According to a second invention, in the first invention,
It further comprises first correction means for correcting the predetermined speed in accordance with the engine speed of the internal combustion engine.
The third invention is the first or second invention, wherein
The apparatus further comprises second correction means for correcting the predetermined speed in accordance with a load of the internal combustion engine.

A fourth invention is any one of the first to third inventions,
The apparatus further comprises third correction means for correcting the predetermined speed based on the cooling water temperature.

According to a fifth invention, in any one of the first to fourth inventions,
A fourth correction means for correcting the predetermined speed according to the altitude is further provided .

According to the first invention, at the time of transition from the catalyst warm-up operation to the normal operation, the phase of the opening / closing timing of the exhaust valve is varied at a predetermined speed based on the amount of residual gas in the cylinder and the amount of hydrocarbon in exhaust. be able to. Therefore, since the speed at which the phase of the exhaust valve opening / closing timing is varied based on the residual gas amount in the cylinder is set to a predetermined speed, the residual gas amount is set to the optimum value when the catalyst warm-up operation is shifted to the normal operation. It becomes possible to control. In addition, since the speed at which the opening / closing timing of the exhaust valve is varied based on the amount of hydrocarbon in the exhaust is set, it is possible to minimize the amount of hydrocarbon during the transition from catalyst warm-up operation to normal operation. . Therefore, the combustion state can be improved, drivability can be stabilized, and the amount of hydrocarbon contained in the exhaust gas can be minimized.

According to the fourth or fifth invention, in order to correct the speed at which the opening / closing timing of the exhaust valve is varied in accordance with the engine speed or the load of the internal combustion engine, the combustion state is changed during the transition from the catalyst warm-up operation to the normal operation. Can be optimized.

According to the sixth aspect of the invention, since the influence of the residual gas on the combustion state changes according to the change in the cooling water temperature, by correcting the speed at which the opening / closing timing of the exhaust valve is varied based on the cooling water temperature, It is possible to optimally control the combustion state.

According to the seventh invention, when the altitude changes, the intake pipe negative pressure fluctuates, and the influence of the residual gas on the combustion state changes. Therefore, the speed at which the opening / closing timing of the exhaust valve is varied according to the altitude is corrected. Thus, the combustion state in the cylinder can be optimally controlled.

  Several embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted. The present invention is not limited to the following embodiments.

Embodiment 1 FIG.
FIG. 1 is a view for explaining an internal combustion engine system and its peripheral structure according to each embodiment of the present invention. An intake passage 12 and an exhaust passage 14 communicate with the internal combustion engine 10. The intake passage 12 includes an air filter 16 at an upstream end. The air filter 16 is assembled with an intake air temperature sensor 18 for detecting the intake air temperature THA (that is, the outside air temperature). An exhaust purification catalyst 32 is disposed in the exhaust passage 14.

  An air flow meter 20 is disposed downstream of the air filter 16. A throttle valve 22 is provided downstream of the air flow meter 20. A throttle sensor 24 that detects the throttle opening degree TA and an idle switch 26 that is turned on when the throttle valve 22 is fully closed are disposed in the vicinity of the throttle valve 22.

  A surge tank 28 is provided downstream of the throttle valve 22. Further, a fuel injection valve 30 for injecting fuel into the intake port of the internal combustion engine 10 is disposed further downstream of the surge tank 28.

  The internal combustion engine 10 includes an intake valve 36 and an exhaust valve 38. The intake valve 36 is connected to a variable valve timing (VVT) 44 for changing the lift amount and / or the operating angle of the intake valve 36. Similarly, a variable valve mechanism 46 for changing the lift amount and / or the operating angle of the exhaust valve 38 is connected to the exhaust valve 38. The variable valve mechanism 44 and the variable valve mechanism 46 both change the lift amount and operating angle of the intake valve 36 and the exhaust valve 38 by the driving force of the electric motor. According to the variable valve mechanism 44 and the variable valve mechanism 46, the lift amount of the intake valve 36 and the exhaust valve 38 and the phase of the operating angle (opening / closing timing) can be continuously varied.

  An ignition plug is provided in the cylinder of the internal combustion engine 10 to ignite the fuel sprayed into the combustion chamber. Further, a piston 34 that reciprocates inside the cylinder is provided in the cylinder. Further, a water temperature sensor 42 for detecting the cooling water temperature is attached to the internal combustion engine 10.

  A crankshaft 48 that is rotationally driven by the reciprocating motion is connected to the piston 34. The vehicle drive system and accessories (air conditioner compressor, alternator, torque converter, power steering pump, etc.) are driven by the rotational torque of the crankshaft 48. A crank angle sensor 50 for detecting the rotation angle of the crankshaft 48 is attached in the vicinity of the crankshaft 48.

  As shown in FIG. 1, the system of the present embodiment includes an ECU (Electronic Control Unit) 40. In addition to the various sensors described above, the ECU 40 detects an atmospheric pressure sensor 52 that detects atmospheric pressure, a KCS sensor that detects knocking, vehicle speed, engine speed, exhaust temperature, lubricating oil temperature, catalyst bed temperature, and the like. Various sensors (not shown) are connected for this purpose. Further, the ECU 40 is connected to each actuator such as the fuel injection valve 30 and the variable valve mechanisms 44 and 46 described above.

  In the system of the present embodiment configured as described above, in the process of warming up the exhaust purification catalyst 32 when the internal combustion engine 10 is started, the phase of the opening / closing timing (open section) of the exhaust valve 38 is retarded than usual. The control which changes to the side is performed. As a result, high expansion can be maintained in the cylinder during the combustion stroke, and the combustion state in the cylinder can be improved. In particular, when the catalyst is warmed up, the phase of the ignition timing is controlled to the retarded side, so that the combustion state can be stabilized by changing the phase of the opening / closing timing of the exhaust valve 38 to the retarded side accordingly. it can.

  Further, if the phase of the opening / closing timing of the exhaust valve 38 is changed to the retard side, the amount of overlap between the valve opening sections of the intake valve 36 and the exhaust valve 38 increases, so the amount of residual gas after combustion in the cylinder increases. be able to. Thereby, the temperature of the air-fuel mixture newly sucked into the cylinder can be raised by the heat of the residual gas, and the amount of hydrocarbon (HC) contained in the exhaust gas can be reduced. On the other hand, if the residual gas amount becomes excessively large, the combustion state in the cylinder becomes unstable. For this reason, the phase of the retard amount of the opening / closing timing of the exhaust valve 38 during catalyst warm-up is set to a value that can increase the residual gas amount as much as possible within a range in which the combustion state does not become unstable.

  In a normal operation state after catalyst warm-up, the phase of the valve opening timing of the exhaust valve 38 is set to the advance side than during warm-up. In this state, since the exhaust purification catalyst 32 has already reached the activation temperature, even if the opening timing of the exhaust valve 38 is advanced to reduce the residual gas amount, the exhaust purification catalyst 32 causes the hydrocarbons in the exhaust to be exhausted. Can be purified.

  On the other hand, in the process of shifting from the catalyst warm-up operation to the normal operation, since the exhaust purification catalyst 32 is becoming active, the amount of hydrocarbon can be reduced even if the residual gas amount is reduced compared to the time when the catalyst warm-up is started. For this reason, when the catalyst warm-up operation is shifted to the normal operation, the phase of the opening / closing timing of the exhaust valve 38 is gradually returned to the normal operation position, and optimal control is performed so that the residual gas amount does not become excessive or insufficient. It is preferable to do.

  FIG. 2 shows changes in the retard amount of the opening / closing timing of the exhaust valve 38, the residual gas ratio in the cylinder, and the amount of hydrocarbons contained in the exhaust during the transition from the catalyst warm-up operation to the normal operation. FIG.

  FIG. 2A is a characteristic diagram showing the relationship between the phase of the retard amount of the opening / closing timing and time, and the process of switching the phase of the retard amount from the value during catalyst warm-up to the value during normal operation. Show. As shown in FIG. 2A, assuming that the phase of the retard amount during normal operation is 0, the phase of the retard amount is set to 30 ° during catalyst warm-up. The catalyst warm-up is performed during a period in which a catalyst warm-up request is issued immediately after the engine is started. The time when the catalyst warm-up request is issued is usually about several tens of seconds from the start.

  In the example of FIG. 2, the catalyst warm-up request is issued from the engine start to time t0. When time t0 is reached and the catalyst warm-up request is canceled, control is performed so that the phase of the retard amount gradually decreases with time as shown in FIG. . Then, when a predetermined time has elapsed from time t0, the phase of the retardation amount is set to zero.

  FIG. 2A shows three characteristics with different speeds (phase variable speeds) for changing the phase of the retard amount. A characteristic B indicated by a broken line in FIG. 2A shows a case where the phase variable speed is set to a low speed, and the phase of the retardation amount is changed from 30 ° to 0 over a relatively long time from time t0. Is done. On the other hand, a characteristic C indicated by a one-dot chain line shows a case where the phase variable speed is set to a high speed, and the phase of the retardation amount is changed from 30 ° to 0 within a relatively short time from time t0. A characteristic A indicated by a solid line indicates a case where the phase variable speed is set between the characteristic A and the characteristic B.

  FIG. 2B shows how the residual gas ratio in the cylinder changes in each of the characteristics A, B, and C shown in FIG. Characteristic A, characteristic B, and characteristic C shown in FIG. 2B respectively correspond to characteristic A, characteristic B, and characteristic C in FIG.

  FIG. 2C shows how the amount of hydrocarbon contained in the exhaust gas changes in each of the characteristics A, B, and C shown in FIG. Characteristic A, characteristic B, and characteristic C shown in FIG. 2C correspond to characteristic A, characteristic B, and characteristic C in FIG.

  As shown in FIGS. 2B and 2C, in the process of switching the phase of the retard amount of the opening / closing timing of the exhaust valve 38 from the value during catalyst warm-up to the value during normal operation, the phase variable speed is set. Residual gas ratio and hydrocarbon amount change accordingly. Therefore, it is preferable to control the residual gas amount and the hydrocarbon amount to optimum values by optimally controlling the phase variable speed.

  For example, if the phase variable speed is lowered as shown in the characteristic B of FIG. 2A, the residual gas ratio increases in the process of changing the phase of the retard amount as shown in FIG. May become unstable.

  Further, when the phase variable speed is increased as shown in the characteristic C of FIG. 2A, the amount of hydrocarbon increases in the process of changing the phase of the retard amount as shown in FIG. May get worse. In particular, after the catalyst warm-up is completed, if the phase of the retard amount is instantaneously changed to 0 at time t0, there is a concern that the residual gas rapidly decreases and the amount of hydrocarbon in the exhaust gas increases. .

  On the other hand, when the phase of the retardation amount is varied in accordance with the characteristic A of FIG. 2A, the residual gas amount can be kept at an appropriate amount as shown in FIG. As shown in C), the amount of hydrocarbon can also be minimized.

  Therefore, in the present embodiment, the phase of the retard amount of the exhaust valve 38 is changed using the characteristic A of FIG. As a result, the residual gas amount can be maintained at an appropriate amount, and the amount of hydrocarbon contained in the exhaust gas can be reduced. Since the optimum phase variable speed indicated by the characteristic A varies depending on the engine specifications, the optimum phase variable speed is determined based on the residual gas amount, hydrocarbon amount, etc. during the transition from the catalyst warm-up operation to the normal operation. It is preferable to obtain the speed in advance.

  Incidentally, even when the phase of the retard amount is changed according to the characteristic A, the residual gas amount and the hydrocarbon amount change when the operating state of the internal combustion engine 10 changes. Therefore, in the present embodiment, in the process of shifting from the catalyst warm-up to the normal operation, the phase is varied at the phase variable speed of the characteristic A, and the phase variable speed is corrected according to the operating state of the internal combustion engine 10. ing. Thereby, the phase variable speed can be controlled more precisely, and the residual gas amount and the hydrocarbon amount can be controlled with high accuracy.

  FIG. 3 shows a map for correcting the phase variable speed in accordance with the engine speed of the internal combustion engine 10. As shown in FIG. 3, as the engine speed increases, the value of the phase variable speed correction coefficient is set to a larger value. The correction coefficient obtained from FIG. 3 is multiplied by the phase variable speed of the characteristic A. Therefore, as the engine speed increases, the phase variable speed can be set higher, and the retard amount can be varied in a shorter time. As the engine speed increases, the catalyst warms up more quickly. Therefore, the higher the engine speed, the higher the phase variable speed. It becomes possible to stabilize the state.

  FIG. 4 shows a map for correcting the phase variable speed according to the load of the internal combustion engine 10. As shown in FIG. 5, as the engine load increases, the value of the phase variable speed correction coefficient is set to a larger value, and the phase variable speed is set to a higher speed. As described above, since the influence of the residual gas on the combustion increases as the engine load increases, it is preferable to advance the opening / closing timing by increasing the phase variable speed.

  Therefore, the phase of the retard amount of the opening / closing timing of the exhaust valve 38 is varied using the characteristic A shown in FIG. 2A, and the phase variable speed is corrected according to the operating state such as the engine speed and load. As a result, it is possible to control the residual gas amount when changing the phase of the retardation amount to an optimum value and to minimize the amount of hydrocarbon.

  Next, a processing procedure in the system of this embodiment will be described based on the flowchart of FIG. The process of FIG. 5 is performed every predetermined time. First, in step S1, the coolant temperature at the time of engine startup, the coolant temperature at the time of target phase calculation, and the integrated intake air amount after startup are acquired.

  In the next step S2, it is determined whether or not the catalyst warm-up operation is being switched to the normal operation. That is, here, it is determined whether or not the time t0 shown in FIG. 3 has elapsed and the control for changing the phase of the retardation amount is being performed. If the catalyst warm-up operation is being switched to the normal operation, the process proceeds to step S3. On the other hand, when the catalyst warm-up operation is not being switched to the normal operation, the processing is terminated (RETURN).

  In step S3, an elapsed time from the start of variable phase of the retard amount (time t0), the intake air amount at the present time, and the engine speed are acquired. A correction coefficient is calculated from the maps of FIGS. 3 and 4 based on the intake air amount and engine speed acquired here.

  In the next step S4, a target value (target phase) of the phase of the retardation amount at the present time is calculated. Specifically, the preset phase variable speed (phase variable speed of characteristic A in FIG. 2A) is corrected using the correction coefficient calculated from the maps of FIGS. Then, the current target phase is calculated based on the corrected phase variable speed and the elapsed time from time t0.

  In the next step S5, the variable valve mechanism 44 is operated based on the target phase calculated in step S4, and the opening / closing timing of the exhaust valve 38 is changed. After step S5, the process ends (RETURN).

  According to the process of FIG. 5, the phase of the retard amount of the exhaust valve 38 can be controlled based on the preset phase variable speed and the elapsed time from the time t0. Therefore, it is possible to control the residual gas amount to an optimum value and to suppress the amount of hydrocarbon contained in the exhaust gas. In addition, since the phase variable speed is corrected based on the operating state such as the intake air amount and the engine speed, the retard amount can be controlled with high accuracy, and the combustion state can be optimally controlled. .

  As described above, according to the first embodiment, after the catalyst warm-up is completed, the phase of the retard amount of the valve opening timing of the exhaust valve 38 is varied at a predetermined speed to return to the normal operation phase. Therefore, the combustion state and drivability can be stabilized, and the amount of hydrocarbon contained in the exhaust gas can be minimized.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described. In the second embodiment, in addition to the control of the first embodiment, the phase variable speed is corrected in consideration of the cooling water temperature at the start.

  The intake pipe negative pressure of the internal combustion engine 10 changes according to the operating conditions of the internal combustion engine 10. For example, when the cooling water temperature is low, the friction of the engine increases, so it is necessary to increase the intake air amount in order to stabilize idling or to obtain a predetermined engine output. For this reason, when the cooling water temperature is low, the opening amount of the throttle valve 22 is larger than when the cooling water temperature is high. In other words, when the cooling water temperature is high, the opening amount of the throttle valve 22 becomes smaller and the intake pipe negative pressure becomes larger than when the cooling water temperature is low.

  FIG. 6 is a characteristic diagram showing a change in the intake pipe pressure when the phase of the retard amount is varied according to the characteristic A shown in FIG. 2A in the process of shifting from the catalyst warm-up to the normal operation.

  In FIG. 6, a characteristic D indicated by a solid line indicates a characteristic when the cooling water temperature is normal temperature (0 ° C. to 25 ° C.). On the other hand, a characteristic E indicated by a broken line indicates a characteristic when the cooling water temperature is high (25 ° C. to 80 ° C.). Thus, when the cooling water temperature is high, the opening amount of the throttle valve 22 is smaller than when the cooling water temperature is low, and the intake air amount is reduced, so that the intake pipe negative pressure is higher than that at normal temperature. .

  Under conditions where the intake pipe negative pressure is high and the amount of intake air is small, the influence of the residual gas on the combustion state becomes large, and it is assumed that the combustion state becomes unstable due to the residual gas. For this reason, in the second embodiment, the higher the coolant temperature, the higher the phase variable speed, and the shorter the time for changing the phase of the retard amount from the value during catalyst warm-up (30 °) to zero. I am doing so.

  FIG. 7 is a characteristic diagram showing the relationship between the phase of the retard amount of the opening / closing timing of the exhaust valve 38 and the time in the system of the second embodiment, and is a characteristic when the catalyst warm-up operation is shifted to the normal operation. Is shown. In FIG. 7, the characteristic at normal temperature corresponds to the characteristic A shown in FIG.

  As shown in FIG. 7, in the second embodiment, the phase variable speed is controlled according to the cooling water temperature, and when the cooling water temperature is high (about 25 ° C. to 80 ° C.), at normal temperature (about 0 ° C. to 25 ° C.). ) Is controlled to increase the phase variable speed. Further, when the cooling water temperature becomes a low temperature of less than 0 ° C., control is performed to make the phase variable speed slower than that at normal temperature. Thereby, it can suppress that residual gas amount runs short, and it becomes possible to suppress the discharge | emission amount of hydrocarbon reliably. Note that at the time when the catalyst warm-up request is canceled, the cooling water temperature is not sufficiently increased because the elapsed time from the engine start is short. Therefore, as shown in FIG. 7, a water temperature of about 0 ° C. to 25 ° C. is a normal temperature, and a temperature higher than that is a high temperature.

  FIG. 8 is a schematic diagram showing a map for realizing the control shown in FIG. As shown in FIG. 8, the value of the correction coefficient for the phase variable speed is set to a larger value as the cooling water temperature becomes higher. Since the correction coefficient is a coefficient that is multiplied by the phase variable speed at the normal temperature according to the characteristic A, according to the map of FIG. 8, the higher the cooling water temperature, the higher the phase variable speed can be set. The retardation amount can be varied in a short time. Therefore, the combustion state can be prevented from becoming unstable due to the influence of the residual gas, and drivability can be improved.

  In addition, when the cooling water temperature is a low temperature of less than 0 ° C., the residual gas has little influence on the combustion state, so the residual gas can be increased by reducing the phase variable speed, and it is included in the exhaust gas. It becomes possible to reduce the amount of hydrocarbons.

  As described above, according to the second embodiment, the phase variable speed of the exhaust valve 38 is varied in accordance with the cooling water temperature. Therefore, when the cooling water temperature is high, by increasing the phase variable speed, The combustion state can be stabilized by suppressing the influence of the residual gas. In addition, when the cooling water temperature is low, it is difficult to be affected by the residual gas, so the amount of hydrocarbon contained in the exhaust gas can be reduced by reducing the phase variable speed. Therefore, it is possible to optimally control the operating state of the internal combustion engine 10.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described. In the third embodiment, in addition to the control in the first and second embodiments, the phase variable speed is corrected in consideration of the change in atmospheric pressure due to altitude.

  When the vehicle on which the internal combustion engine 10 is mounted travels on a high altitude with a high altitude, the atmospheric pressure is low, so the intake pipe negative pressure becomes smaller than when traveling on a low altitude. FIG. 9 is a characteristic diagram showing a change in the intake pipe pressure when the phase of the retard amount is varied in accordance with the characteristic A in FIG. 2A in the process of shifting from the catalyst warm-up to the normal operation.

  In FIG. 9, a characteristic F indicated by a solid line indicates a characteristic in a lowland. On the other hand, a characteristic G indicated by a broken line indicates a characteristic at high altitude. In high altitude operation, since the atmospheric pressure is reduced, the intake pipe negative pressure of the characteristic G is smaller than that of the characteristic F.

  As described in the second embodiment, the higher the intake pipe negative pressure, the greater the influence of the residual gas on the combustion state. On the other hand, when the intake pipe negative pressure is low, since the residual gas has little influence on the combustion state, it is preferable to reduce the amount of hydrocarbon by the residual gas.

  For this reason, in the third embodiment, the phase variable speed is set to a low speed in high altitude operation where the intake pipe negative pressure is reduced. FIG. 10 is a characteristic diagram showing the relationship between the phase of the retard amount of the opening / closing timing of the exhaust valve 38 and the time in the system of the third embodiment, and is a characteristic when the catalyst warm-up operation is shifted to the normal operation. Is shown. In FIG. 11, the lowland characteristic corresponds to the characteristic A shown in FIG.

  As shown in FIG. 10, in high altitude operation, the phase variable speed is set to be lower than in low altitude operation. In this way, in high altitude operation where the intake pipe pressure is low, the residual gas has little effect on the combustion state.Therefore, by setting the phase variable speed to a low speed, sufficient residual gas can be obtained during the transition to normal operation. Can be much more. Therefore, the amount of hydrocarbons in the exhaust can be suppressed, and exhaust emission can be improved.

  FIG. 11 is a schematic diagram showing a map for realizing the control shown in FIG. As shown in FIG. 11, the higher the altitude of the place where the internal combustion engine 10 is operated, the smaller the value of the phase variable speed correction coefficient is set. Since the correction coefficient is a coefficient that is multiplied by the low-level phase variable speed due to the characteristic A, according to the map of FIG. 12, the higher the altitude, the lower the phase variable speed can be set.

  As described above, according to the third embodiment, the phase variable speed is varied according to the altitude of the place where the internal combustion engine 10 is operated. Therefore, the higher the altitude, the lower the phase variable speed. When the catalyst warm-up operation is followed by the normal operation, the residual gas amount can be optimally controlled. Thereby, it becomes possible to minimize the amount of hydrocarbons in the exhaust, and the exhaust emission can be improved.

  In each of the above-described embodiments, the combustion state in the cylinder is controlled by controlling the opening / closing timing of the exhaust valve 38. However, the combustion state can be controlled by controlling the opening / closing timing of the intake valve 36. good.

It is a figure for explaining an internal combustion engine system concerning each embodiment of the present invention, and its peripheral structure. FIG. 6 is a characteristic diagram showing changes in the phase of the retard amount of the opening / closing timing of the exhaust valve, the residual gas amount, and the amount of hydrocarbon contained in the exhaust gas in the process of shifting from the catalyst warm-up operation to the normal operation. It is a schematic diagram which shows the map for correct | amending a phase variable speed according to the engine speed of an internal combustion engine. It is a schematic diagram which shows the map for correct | amending a phase variable speed according to the load of an internal combustion engine. 3 is a flowchart illustrating a processing procedure in the system according to the first embodiment. FIG. 4 is a characteristic diagram showing a change in intake pipe pressure when the phase of the retard amount is varied according to the characteristic A shown in FIG. 3 in the process of shifting from the catalyst warm-up to the normal operation. In the system of Embodiment 2, it is a characteristic view which shows the relationship between the phase of retard amount of the opening / closing timing of an exhaust valve, and time. It is a schematic diagram which shows the map for implement | achieving the control shown in FIG. FIG. 4 is a characteristic diagram showing a change in intake pipe pressure when the phase of the retard amount is varied according to the characteristic A in FIG. 3 in the process of shifting from the catalyst warm-up to the normal operation. FIG. 10 is a characteristic diagram showing the relationship between the phase of the retard amount of the opening / closing timing of the exhaust valve and time in the system of the third embodiment. It is a schematic diagram which shows the map for implement | achieving the control shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 24 Intake valve 20 Injector 40 ECU

Claims (5)

Variable valve operating means for varying the opening and closing timing of the exhaust valve;
When a catalyst warm-up request is issued, a catalyst warm-up operation is performed by changing the phase of the opening / closing timing to the retard side, and when the warm-up request is canceled, the phase of the opening / closing timing is changed. Catalyst warm-up means for shifting to the normal operation, which is variable to the advance side than that during the catalyst warm-up operation,
When migrating to the normal operation from the catalyst warm-up operation, the phase variable speed set based on the hydrocarbon content of the residual gas quantity and the exhaust of the cylinder, the speed for changing the phase of the opening and closing timing at a predetermined speed Setting means;
An internal combustion engine system comprising: An internal combustion engine system according to claim 1, further comprising a first correcting means for correcting the predetermined speed according to the engine speed of the internal combustion engine. 3. The internal combustion engine system according to claim 1, further comprising second correction means for correcting the predetermined speed in accordance with a load of the internal combustion engine. The internal combustion engine system according to any one of claims 1 to 3, further comprising third correction means for correcting the predetermined speed based on a coolant temperature. 5. The internal combustion engine system according to claim 1 , further comprising a fourth correction unit that corrects the predetermined speed in accordance with an altitude.

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