JP5593737B2 - Control device for internal combustion engine and auxiliary power mechanism - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine and an auxiliary power mechanism that are preferably used in, for example, a hybrid vehicle.

  As a conventional technique, for example, as disclosed in Japanese Patent Application Laid-Open No. 60-13929, there is known a control device for an internal combustion engine provided with a variable valve mechanism for stopping an intake valve and an exhaust valve. ing. In the prior art, when one of the intake valve and the exhaust valve fails and this valve does not return from the valve stop state, the other valve that is operating normally in the cylinder is also stopped. Yes. As a result, in the prior art, a state where only one of the intake valve and the exhaust valve is operated is avoided.

JP 60-13929 A

  By the way, in a hybrid vehicle or the like, since the internal combustion engine is stopped and restarted even while the vehicle is running, a variable valve mechanism of a system in which the intake valves (or exhaust valves) of all cylinders are simultaneously stopped and returned. (Hereinafter, referred to as an all-cylinder drive type variable valve mechanism) may be used. However, in the all-cylinder drive type variable valve mechanism, for example, if the intake valves of some cylinders fail while the valves are stopped, applying the control method of the prior art will stop all the exhaust valves at the same time. There is a problem that the internal combustion engine must be stopped. Further, in this case, there is also a problem that the engine stop is continued without considering the possibility that the valve spontaneously recovers even if it is a minor failure caused by temporary sticking of the valve or the like.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a system that includes a variable valve mechanism of an all-cylinder drive type, even if the valve system fails. It is an object of the present invention to provide a control device for an internal combustion engine and an auxiliary power mechanism that can reliably perform the retreat travel and can maintain an opportunity for the valve system to naturally return during the retreat travel.

A first invention includes an internal combustion engine equipped with a plurality of cylinders having an intake valve and an exhaust valve;
An auxiliary power mechanism constituting a power source together with the internal combustion engine;
A variable valve mechanism on the intake side that simultaneously stops and returns the intake valves of all cylinders;
A variable valve mechanism on the exhaust side that stops and resets the exhaust valves of all cylinders simultaneously,
Even when an operation of returning the intake valve and the exhaust valve by the variable valve mechanism is performed, when a valve return abnormality occurs in which one of the intake valve and the exhaust valve does not return, Valve return abnormality response means for stopping the other valve in which the valve return abnormality has not occurred while holding the one valve in a state in which the one valve can be naturally returned by a variable valve mechanism;
Retreat travel control means for stopping fuel injection of the internal combustion engine and performing retreat travel by the driving force of the auxiliary power mechanism when the valve return abnormality occurs;
An engine that, when the valve return abnormality occurs, causes the internal combustion engine to idle in a state where the self-sustained operation is stopped using the driving force of the auxiliary power mechanism while maintaining the one valve in a state where it can be naturally returned Idling control means,
It is characterized by providing.

According to a second invention, the valve return abnormality handling means is
An abnormal cylinder specifying means for specifying a cylinder in which the valve return abnormality of the one valve has occurred based on the operation information of the internal combustion engine;
All-cylinder abnormality response means for immediately stopping the valve when the valve return abnormality of the one valve occurs in all cylinders;
When a valve return abnormality of the one valve occurs in some cylinders, both the exhaust valve and the intake valve are stopped after a predetermined standby time has elapsed, and the valve return is performed during the standby time. A partial cylinder abnormality countermeasure means that does not stop the valve when the abnormality recovers;
It is set as the structure provided with.

  According to a third aspect of the invention, the standby time includes a first standby time used when the exhaust valve returns abnormally and a second standby time used when the intake valve returns abnormally. The waiting time is set shorter than the second waiting time.

  According to a fourth aspect of the present invention, the retreat travel control means includes retreat travel stop means for stopping the retreat travel and restarting the operation of the internal combustion engine when the valve return abnormality is recovered.

  According to a fifth aspect of the present invention, the valve stop prohibiting means is configured to prohibit the intake valve and the exhaust valve from being stopped again by the variable valve mechanism when the valve return abnormality is recovered.

  According to a sixth aspect of the present invention, there is provided an idling stop means for interrupting power transmission from the auxiliary power mechanism to the internal combustion engine when the continuation time of the retreat travel exceeds a predetermined reference time without recovering the valve return abnormality. It is set as the structure provided with.

  In a seventh aspect of the invention, the reference time is set according to a time from when the idling of the internal combustion engine is started until the amount of lubricating oil sucked into the cylinder reaches an allowable limit.

Eighth invention, when the duration of the evacuation travel in a state where the valve return abnormality is not recovered exceeds a predetermined time limit, the valve stop of that due to the variable valve mechanism wherein the intake valve and the exhaust valve the rewritable canceled, and configured to include the evacuation travel limiting means to terminate the evacuation travel.

  According to the first aspect, the retreat travel control means can reliably perform the minimum retreat travel in order to move the vehicle to a safe place even when the internal combustion engine has failed due to the valve return abnormality. Further, the valve return abnormality handling means can stop at least the other valve when a valve return abnormality of one of the intake valve and the exhaust valve occurs. As a result, even when a valve return abnormality occurs, it is possible to protect the components of the internal combustion engine and ensure the quietness of the vehicle and the cruising distance of the retreat travel. Further, according to the engine idling control means, the internal combustion engine can be idling while the self-sustained operation is stopped by the driving force of the auxiliary power mechanism during the retreat traveling. Thereby, it is possible to maintain an opportunity for the valve to naturally return during the retreat travel and to increase the possibility that the vehicle recovers. In addition, the cranking load at the time of restart can be reduced, and vibrations can be prevented.

  According to the second aspect of the invention, the all-cylinder abnormality handling means can immediately stop the other valve when the valve return abnormality of one of the intake valve and the exhaust valve occurs in all the cylinders. . In addition, the partial cylinder abnormality handling means can secure an opportunity for the valve to spontaneously return according to the standby time when a valve return abnormality occurs in some cylinders. In addition, after the standby time elapses, the intake valve and the exhaust valve can be stopped in both the normal cylinder and the failed cylinder, and a malfunction due to the operation of only one of the valves can be avoided in all the cylinders. Therefore, appropriate response control can be performed according to the number of failed cylinders (all cylinders or some cylinders).

  According to the third aspect of the invention, the first standby time used when the exhaust valve returns abnormally can be set shorter than the second standby time used when the intake valve returns abnormally. As a result, when the exhaust valve fails, it is possible to shorten the time for waiting for the natural return to suppress the vibration continuation time and to ensure drivability. In addition, when the intake valve fails, the time for waiting for a natural return can be made as long as possible within a range in which oil rise is allowed. Therefore, appropriate response control can be performed according to the type of the failed valve.

  According to the fourth invention, the retreat travel stop means can stop the retreat travel and resume the operation of the internal combustion engine when the valve return abnormality is recovered. Thereby, when the valve return abnormality due to a temporary response delay or the like is recovered, it is possible to quickly return to the normal operation state.

  According to the fifth invention, the valve stop prohibiting means can prohibit the intake valve and the exhaust valve from being stopped again by the variable valve mechanism when the valve return abnormality is recovered. As a result, it is possible to avoid the valve stop being executed in a situation where the valve return abnormality is likely to recur, and to reliably prevent the failure from reoccurring.

  According to the sixth invention, the idling stop means can stop idling of the internal combustion engine when the duration of the evacuation travel exceeds the predetermined reference time in a state where the valve return abnormality is not recovered. Thereby, while maintaining the opportunity for the internal combustion engine to naturally return as much as possible, when the natural recovery cannot be expected, the internal combustion engine can be completely stopped to extend the cruising distance.

  According to the seventh aspect of the present invention, the idling of the internal combustion engine can be stopped before the amount of oil rising exceeds the allowable limit while maintaining the opportunity for the internal combustion engine to naturally return as much as possible.

  According to the eighth aspect of the invention, the retreat travel restriction means can terminate the retreat travel when the duration of the retreat travel exceeds the predetermined limit time without recovering the valve return abnormality. Thereby, the cranking load at the time of restart can be reduced and startability can be improved.

It is a block diagram of the engine applied to Embodiment 1 of this invention. It is a block diagram which shows the system configuration | structure of the hybrid vehicle applied to Embodiment 1 of this invention. It is a block diagram which shows schematically the variable valve mechanism of an all cylinder drive type. It is a perspective view which expands and shows a part of variable valve mechanism. In Embodiment 1 of this invention, it is a flowchart of the control performed by ECU. In Embodiment 1 of this invention, it is a flowchart of the control performed by ECU. In Embodiment 1 of this invention, it is a flowchart of the control performed by ECU. In Embodiment 2 of this invention, it is a flowchart of the control performed by ECU.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of an engine applied to Embodiment 1 of the present invention. The system of the present embodiment includes an engine 10 composed of a multi-cylinder internal combustion engine. FIG. 1 illustrates one cylinder among a plurality of cylinders mounted on the engine 10. Each cylinder of the engine 10 is provided with a piston 12. The piston 12 forms a combustion chamber 14 in each cylinder and is connected to a crankshaft 16. An intake port and an exhaust port are provided in the combustion chamber 14 of each cylinder. The intake port is connected to an intake passage 18 for sucking intake air into the combustion chamber 14 (in the cylinder), and the exhaust port is connected to an exhaust passage 20 for discharging exhaust gas from the cylinder. The intake passage 18 is provided with an air flow sensor 22 that detects the intake air amount and an electronically controlled throttle valve 24 that increases or decreases the intake air amount.

  Each cylinder has a fuel injection valve 26 for injecting fuel into the intake port, an ignition plug 28 for igniting an air-fuel mixture in the cylinder, an intake valve 30 for opening and closing the intake port with respect to the cylinder, An exhaust valve 32 is provided for opening and closing the exhaust port with respect to the cylinder. The engine 10 also has an all-cylinder drive variable intake valve operating mechanism 34 for stopping and returning the intake valves 30 of all cylinders simultaneously, and an all-cylinder drive for simultaneously stopping and returning the exhaust valves 32 of all cylinders. And an exhaust variable valve mechanism 36 of the type. These variable valve mechanisms 34 and 36 will be described later.

  Furthermore, the system of the present embodiment includes a sensor system including a crank angle sensor 38 and the like, and an ECU (Electronic Control Unit) 40 for controlling the operating state of the engine 10. The crank angle sensor 38 outputs a signal synchronized with the rotation of the crankshaft 16, and the ECU 40 can detect the engine speed and the crank angle based on this output. In addition to the sensors 22 and 38, the sensor system includes various sensors (for example, a water temperature sensor that detects the temperature of engine cooling water, an intake pressure sensor that detects intake pressure, and a throttle) that are necessary for vehicle and engine control. A throttle sensor that detects the opening, an accelerator opening sensor that detects the accelerator opening, an air-fuel ratio sensor that detects the exhaust air-fuel ratio, and the like. These sensors are connected to the input side of the ECU 40. Further, various actuators including a throttle valve 24, a fuel injection valve 26, a spark plug 28, and valve stop actuators 90 and 92 described later are connected to the output side of the ECU 40.

  The ECU 40 detects operation information of the engine by a sensor system, and performs operation control by driving each actuator based on the detection result. Specifically, the engine speed and the crank angle are detected based on the output of the crank angle sensor 38, and the engine load is calculated based on the intake air amount detected by the air flow sensor 22 and the engine speed. Further, the fuel injection timing, ignition timing, etc. are determined based on the detected value of the crank angle. Then, the fuel injection amount is calculated based on the intake air amount, the engine load, etc., and the fuel injection valve 26 is driven and the spark plug 28 is driven. Further, the ECU 40 executes a fuel cut (F / C) for stopping the fuel injection at the time of deceleration or the like.

  On the other hand, in the present embodiment, the engine 10 is mounted on the vehicle 50 of the hybrid vehicle. FIG. 2 is a configuration diagram showing a system configuration of the hybrid vehicle applied to the first embodiment of the present invention. As shown in FIG. 2, an electric motor 52, a power split mechanism 54, and the like are mounted on the vehicle 50, and these constitute an auxiliary power mechanism of the present embodiment. The electric motor 52 constitutes a power source of the vehicle together with the engine 10, and the output side of the engine 10 and the electric motor 52 is connected to the power split mechanism 54. The output side of the power split mechanism 54 is connected to a wheel 58 via a transmission mechanism 56 including a speed reduction mechanism and the like, and is also connected to a generator. The electric motor 52 and the generator are connected to the battery via an inverter.

  Here, the power split mechanism 54 transmits the driving force of the engine 10 and the electric motor 52 to the transmission mechanism 56 at a desired ratio in accordance with a control signal input from the ECU 40. Therefore, the ECU 40 can arbitrarily change the distribution of the driving force of the engine 10 and the electric motor 52 transmitted to the wheel 58 side by controlling the power split mechanism 54. As a result, engine traveling that travels by the driving force of the engine 10, EV traveling that travels by the driving force of the electric motor 52, and HV traveling that uses both driving forces are realized.

  Next, the variable valve mechanisms 34 and 36 mounted on the engine 10 will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram schematically showing an all cylinder drive type variable valve mechanism, and FIG. 4 is an enlarged perspective view showing a part of the variable valve mechanism. Since the two variable valve mechanisms 34 and 36 have the same structure, in the following description, the structure of the intake variable valve mechanism 34 will be described as an example. In the present embodiment, for example, in the four-cylinder engine 10, two intake valves 30 and two exhaust valves 32 are arranged in each cylinder.

  First, FIG. 3 is a partial cross-sectional view in which a part of the variable valve mechanism 34 is broken and shown on a plane including an axis of a rocker shaft 68 and an axis of switching pins 72, 74, 76, which will be described later. As shown in FIG. 3, the variable valve mechanism 34 is configured such that when the first rocker arm 64 receives the acting force from the cam 62 of the camshaft 60 and the first rocker arm 64, the acting force of the cam 62 is applied to the intake valve 30. A rocker shaft 68 having a hollow structure that supports the rocker arms 64 and 66 so as to be swingable, and a switching mechanism 70 that switches a connection state of the rocker arms 64 and 66. Here, the cam 62, the rocker arms 64 and 66, and the switching mechanism 70 are arranged in each cylinder.

  The switching mechanism 70 urges the three switching pins 72, 74, 76 arranged in the axial direction with their end faces in contact with each other and the switching pins 72, 74, 76 toward the link arm 80 (102). And a return spring 78. Of the switching pins 72 to 76, the central switching pin 72 is movably inserted into a pin hole provided in the first rocker arm 64, and the left and right switching pins 74 and 76 are connected to the second rocker arm 66. The pin hole is provided so as to be movable. On the other hand, of the link arms 80 and 82 with which the right switching pin 76 contacts, the first link arm 80 is disposed in any one cylinder (for example, # 4 cylinder), and the second link arm 82 is connected to other cylinders. (# 1 to # 3 cylinders). These link arms 80 and 82 are supported by a rocker shaft 68 so as to be swingable. A link shaft 84 is movably disposed on the inner peripheral side of the rocker shaft 68. The link arms 80 and 82 are fixed to the link shaft 84 by a fixing pin 86 and are displaced together with the link shaft 84 in the axial direction and the circumferential direction.

  Further, as shown in FIG. 4, the first link arm 80 is provided with a protrusion 80 a that protrudes toward the outer periphery of the camshaft 60. On the other hand, the camshaft 60 is provided with a spiral guide groove 88 at a position corresponding to the protrusion 88. A valve stop actuator 90 made of an electromagnetic solenoid or the like is provided in the vicinity of the first link arm 80, and the valve stop actuator 90 includes a drive shaft 90a. The valve stop actuator 90 is configured to engage the protrusion 80 a of the first link arm 80 with the guide groove 88 when energized from the ECU 40.

  Next, the operation of the variable valve mechanism 34 described above will be described. First, when the variable valve mechanism 34 is not operated (the valve stop actuator 90 is not energized), the first link arm 80 receives the biasing force of the return spring 78 at a position away from the camshaft 60. , Located at the displacement end Pmax1 shown in FIG. In this state, the rocker arms 64, 66 are connected via the switching pins 72, 74, so that the acting force of the cam 62 is applied to the two intake valves 30 from the first rocker arm 64 via the second rocker arm 66. Is transmitted to. Therefore, the intake valve 30 performs a normal opening / closing operation against the spring force of the valve spring 30a (see FIG. 4) according to the profile of the cam 62.

  On the other hand, when the valve stop actuator 90 is energized, the projection 80a of the first link arm 80 is pushed by the drive shaft 90a. As a result, the protrusion 80a engages with the guide groove 88 of the camshaft 60 and is guided by the guide groove 88 that rotates together with the camshaft 60 in this state, thereby moving toward the displacement end Pmax2 shown in FIG. Move in the axial direction. As a result, the link arms 80 and 82 are displaced together with the rocker shaft 68 in the axial direction, and push the switching pins 72, 74, and 76 of each cylinder toward the return spring 78. When the central switching pin 72 reaches a position where it is just accommodated in the pin hole of the first rocker arm 64, the connected state of the rocker arms 64 and 66 is released. As a result, even if the first rocker arm 64 swings due to the acting force of the cam 62, this swinging motion is not transmitted to the second rocker arm 66. As a result, in all cylinders, the intake valve 30 is not subjected to the acting force of the cam 62, and is thus kept closed by the valve spring 30a.

  In this manner, the ECU 40 can stop the intake valves 30 of all the cylinders at the same time (hold the valve closed) by energizing the valve stop actuator 90. When energization of the valve stop actuator 90 is stopped, the intake valves 30 of all cylinders can be simultaneously returned to perform normal opening / closing operations. On the other hand, the exhaust variable valve mechanism 36 is configured similarly to the intake variable valve mechanism 34 described above, and includes a valve stop actuator 92. Therefore, the ECU 40 can simultaneously stop and return the exhaust valves 32 of all the cylinders by energizing and deenergizing the valve stop actuator 92.

[Features of Embodiment 1]
In the engine control described above, when the vehicle performs a deceleration operation, fuel cut is performed, and the variable valve mechanisms 34 and 36 hold the intake valves 30 and the exhaust valves 32 of all the cylinders in the valve stop state. When the deceleration operation is cancelled, the fuel cut is stopped and the fuel injection is restarted, the energization to the variable valve mechanisms 34 and 36 is stopped, and the intake valves 30 and the exhaust valves 32 of all the cylinders are returned to the valve. Let However, the intake valve 30 and the exhaust valve 32 may be stuck in a closed state due to some abnormality, and even if energization to the variable valve mechanisms 34 and 36 is stopped, the valve may not return. Therefore, in this embodiment, when such a valve return abnormality occurs, a valve return abnormality response control and an abnormal time travel control described below are performed.

(Valve return abnormality control)
In the valve return abnormality control, first, valve return abnormality occurs in the state where the energization to the variable valve mechanisms 34 and 36 is stopped (the state where all the intake valves 30 and the exhaust valves 32 should be returned). Cylinder (failed cylinder) is detected. This detection process is performed based on operation information (intake pressure, torque, crank angle, etc.) of the engine 10. More specifically, when a valve return abnormality occurs, the engine intake pressure, torque, etc., vary in a different pattern than normal, and the fluctuation pattern is determined by the position (number) of the failed cylinder and the failure. It depends on the type of valve. Therefore, if the fluctuation pattern of the intake pressure and torque detected by the sensor system is compared with the normal pattern, the failed cylinder can be specified, and which of the intake cylinder and the exhaust valve is malfunctioning in the failed cylinder? Can be specified.

  Then, when a valve return abnormality is detected by at least one valve by the detection operation, the retreat travel mode is performed. In the retreat travel mode, the fuel cut is executed (resumed), and the self-sustaining operation of the engine 10 is stopped. Then, the electric motor 52 is operated, and the vehicle is EV-driven by the driving force of the motor. As a result, even when the engine has failed due to a valve return abnormality, the minimum retreat travel can be reliably performed in order to move the vehicle to a safe place.

  In the retreat travel mode, the engine 10 is prohibited from being completely stopped (hereinafter, this control is referred to as engine stop prohibition control). The completely stopped state of the engine is a stopped state in which the crankshaft 16 is stationary and the engine speed is zero. More specifically, in the engine stop prohibition control, the driving force of the electric motor 52 is transmitted to the crankshaft 16 through the power split mechanism 54 and the like, and the engine 10 is idled in a state where the independent operation is stopped. Thus, the reason why the engine stop prohibition control is performed is as follows.

  The valve return abnormality caused by the sticking of the valve or the like may be only a temporary response delay of the return operation, and may return spontaneously while the engine is idling. For this reason, if the engine is completely stopped when the valve return abnormality occurs, the opportunity for natural return is missed. In addition, when the evacuation travel ends with the engine completely stopped, and then the engine is restarted with the intake valve and the exhaust valve stopped, the compression operation is performed even in the cylinders in the exhaust stroke. The load at the time of ranking increases, and vibration and the like easily occur. Therefore, in the present embodiment, the retreat travel is performed while the engine 10 is idling in the stopped state. As a result, even when a valve return abnormality occurs, it is possible to maintain an opportunity for the valve to naturally return during retreat travel, and to increase the possibility that the vehicle will return to a normal state. In addition, the cranking load at the time of restart can be reduced, and vibrations can be prevented.

  On the other hand, when the intake valve 30 or the exhaust valve 32 does not return, the following problem occurs. That is, for example, when the exhaust valve does not return, the exhaust gas flows back to the intake system when the intake valve is opened, causing vibration and noise. Also, if the intake valve does not return, the negative pressure in the cylinder increases during the intake stroke, so that a phenomenon (so-called oil rise) occurs in which the lubricating oil stored on the oil pan side is sucked into the cylinder. Consumption increases. Further, if the engine is operated with only one of the intake valve and the exhaust valve being operated, an unexpected load is applied to each component, or a load (resistance) required for idling the engine by EV traveling increases. there is a possibility.

  For this reason, in the valve return abnormality control, when at least one of the intake valve 30 and the exhaust valve 32 has a valve return abnormality, the other valve that is in a normal state is changed to the variable valve mechanism 34 (36). It is set as the structure which stops a valve by. More specifically, first, for example, when the valve return abnormality of the exhaust valve 32 occurs in all cylinders, significant vibration easily occurs due to the backflow of the exhaust gas described above. The intake valve 30 is immediately stopped. Further, when the valve return abnormality of the intake valve 30 occurs in all the cylinders, the oil consumption rises and the oil consumption increases rapidly. Therefore, the exhaust valves 32 of all the cylinders are immediately stopped by the variable exhaust valve mechanism 36. . As a result, even when a valve return abnormality occurs, it is possible to protect engine components and ensure the quietness of the vehicle and the cruising distance of EV travel.

  Next, a case where a valve return abnormality occurs in only some cylinders will be described. First, for example, in the case where an exhaust valve return abnormality occurs only in a part of the cylinders, when the intake valves of all the cylinders are stopped, the above-described oil rise increases rapidly in the cylinders in which the exhaust valves are normal. Therefore, in this case, first, the system waits for a predetermined waiting time α while monitoring whether the failed exhaust valve does not return spontaneously. After the waiting time α elapses, it is determined that natural recovery cannot be expected, and both the variable valve mechanisms 34 and 36 are energized to stop the intake valves 30 and the exhaust valves 32 of all the cylinders. On the other hand, when the failed exhaust valve naturally returns during the elapse of the waiting time α, the retreat travel mode is canceled according to the situation without executing the valve stop of the intake valve.

  In addition, when the valve return abnormality of the intake valve occurs only in some cylinders, when the exhaust valves of all the cylinders are stopped, the above-described exhaust gas reverse flow occurs in the cylinders in which the intake valves are normal. Therefore, in this case, the system waits for a predetermined waiting time β while monitoring whether the failed intake valve does not return spontaneously. Then, after the standby time β has elapsed, both the variable valve mechanisms 34 and 36 are energized to stop the intake valves 30 and the exhaust valves 32 of all the cylinders. Further, when the failed intake valve naturally returns during the waiting time β, the evacuation travel mode is canceled according to the situation without performing the valve stop of the exhaust valve.

  According to the above control, when the valve return abnormality occurs in some cylinders, it is possible to secure an opportunity for the valve to return naturally by the standby times α and β. In addition, after the standby times α and β have elapsed, the intake valve and the exhaust valve can be stopped in both the normal cylinder and the malfunctioning cylinder, and problems due to the operation of only one of the valves can be avoided in all cylinders. Can do. Therefore, appropriate response control can be performed according to the number of failed cylinders (all cylinders or some cylinders).

  Further, during the above-described waiting time α, since only the intake valve is operating in the cylinder in which the exhaust valve has failed, there is a high possibility that vibration has occurred due to the backflow of the exhaust gas. On the other hand, during the elapse of the waiting time β, since only the exhaust valve is operating in the cylinder in which the intake valve has failed, there is a high possibility that the oil increase has increased rapidly. When these conditions are compared, the occurrence of vibration has a great influence on the drivability, so it is considered to be a more serious problem than oil rise. For this reason, the first waiting time α is set to be shorter than the second waiting time β (α <β).

  As a result, when the exhaust valve fails, it is possible to shorten the time for waiting for the natural return to suppress the vibration continuation time and to ensure drivability. In addition, when the intake valve fails, the time for waiting for a natural return can be made as long as possible within a range in which oil rise is allowed. Therefore, appropriate response control can be performed according to the type of the failed valve. Note that the values of the waiting times α and β described above are set as counter values for comparison with an abnormal elapsed time counter C1 described later, and are stored in the ECU 40 in advance. Therefore, the counter value of the standby time α is set to a value smaller than the standby time β.

(Travel control during abnormal conditions)
Next, the abnormal time traveling control will be described. The abnormal time travel control is performed as a secondary response process after the above-described valve return abnormality response control (primary response process) is performed. It controls the duration and idling state of the engine. In the abnormality traveling control, when the valve return abnormality is recovered, the retreat traveling by the electric motor 52 is stopped and the operation of the engine 10 is resumed. The engine operation is resumed by stopping energization of the variable valve mechanisms 34 and 36, returning the intake valve 30 and the exhaust valve 32, and restarting fuel injection. Thereby, when the valve return abnormality due to a temporary response delay or the like is recovered, it is possible to quickly return to the normal operation state.

  Further, in the abnormal time traveling control, the idling of the engine 10 is stopped when the duration of the evacuation traveling exceeds a predetermined reference time γ in a state where the valve return abnormality is not recovered. Specifically, the power transmission from the electric motor 52 to the engine 10 is interrupted by controlling a clutch mechanism or the like mounted on the power split mechanism 54, and the engine 10 is allowed to be completely stopped. Here, when the engine is idled during retreat, an excessive load is applied to the motor, and the power consumption of the motor increases and the cruising distance decreases.

  For this reason, in the abnormal time travel control, the engine stop prohibition control is canceled at the time when the reference time γ is passed so that it is confirmed that the engine does not recover naturally after the start of the retreat travel. Disconnect the engine from the power system. Thereby, while maintaining the opportunity for the engine to return spontaneously as much as possible, when the natural recovery cannot be expected, the engine can be completely stopped to extend the cruising range. When permitting the complete stop of the engine, in order to reduce the cranking load at the time of restart, the energization to the exhaust variable valve mechanism 36 is stopped and the exhaust valve is held in a state where the valve can be returned. Is preferred.

  Note that if the engine is idling while the valve is stopped (the valve is not returning), the amount of oil rise increases. Therefore, the above-mentioned reference time γ is the allowable amount of oil rise after the engine has started idling. You may set according to the time until it reaches. Here, the relationship between the duration of idling and the amount of oil rise can be easily obtained by experiments or the like. According to this configuration, it is possible to stop the idling of the engine before the amount of oil rising exceeds the allowable limit while maintaining the opportunity for the engine to return naturally.

  Furthermore, in the abnormal time traveling control, even when the valve return abnormality is recovered during retreat traveling and the engine is restarted, the valve stop by the variable valve mechanisms 34 and 36 is prohibited. This is because the valve in which the valve return abnormality has occurred is considered to be easily stuck for some reason, and if the valve is stopped after recovery, the valve once returned may be stuck again. For this reason, the valve stop is not executed again after the recovery from the valve return abnormality. According to this configuration, it is possible to avoid the valve stop being executed in a situation where the valve return abnormality is likely to recur, and it is possible to reliably prevent the failure from reoccurring.

[Specific Processing for Realizing Embodiment 1]
Next, specific processing for realizing the control described above will be described with reference to FIGS. 5 to 7 are flowcharts of control executed by the ECU in the first embodiment of the present invention. The routines shown in these drawings are repeatedly executed during operation of the engine.

  First, in the routine shown in FIG. 5, the variable valve mechanisms 34 and 36 hold the intake valves 30 and the exhaust valves 32 of all the cylinders in the valve stop state and perform the fuel cut when the engine is decelerated. It is determined whether or not there is (step 100). Then, when the deceleration operation is completed, it is determined whether or not there is a request to return from the fuel cut to the normal fuel injection state (step 102). When these two determinations are satisfied, the intake side and exhaust side variable valve mechanisms 34 and 36 are stopped, and the intake valves and exhaust valves of all the cylinders are returned to their normal operating states (step 104). If any of the determinations in steps 100 and 102 is not established, the control is terminated because it is not the timing to perform the valve return.

  In the next processing, after the variable valve mechanisms 34 and 36 are stopped, the operation of the intake valve and the exhaust valve of each cylinder is confirmed based on the operation information of the engine, and it is determined whether or not all the valves have returned. (Step 106). When this determination is established, it is determined that the valve return has been normally performed for all the cylinders, and the control is terminated. On the other hand, if the determination in step 106 is not established, a valve return abnormality has occurred in any of the valves, so that the valve return abnormality response control and the abnormal time running control are executed (steps 108 and 110).

  Next, referring to FIG. 6, the processing of the valve return abnormality handling control executed in step 108 in FIG. 5 will be described. In the routine shown in FIG. 6, first, since valve return abnormality has occurred, counting by the abnormality elapsed time counter C1 is started (step 200). The abnormal elapsed time counter C1 is a counter that measures the elapsed time after the valve return abnormality has occurred, and is incremented every predetermined time by the timer function of the ECU 40. Further, in response to the occurrence of the valve return abnormality, the ECU 40 restarts the fuel cut and performs the EV retreat travel mode (steps 202 and 204). Thus, in the retreat travel mode, the vehicle travels EV by the driving force of the electric motor 52 in a state where the independent operation of the engine is stopped.

  In the next processing, the type of cylinder and valve in which valve return abnormality has occurred is detected based on engine operation information. Then, it is determined whether or not a valve return abnormality has occurred in the exhaust valve. When this determination is satisfied, it is further determined whether or not a failure has occurred in all the cylinders (steps 206 and 208). If the determinations in steps 206 and 208 are both satisfied, an exhaust valve return abnormality has occurred in all the cylinders. Therefore, the intake variable valve mechanism 34 is operated to stop the intake valves in all the cylinders ( Step 210). Then, engine stop prohibition control is executed by idling the engine using the driving force of the electric motor 52 (step 212).

  Further, when the determination in step 208 is not established, an exhaust valve return abnormality has occurred in some cylinders. In this case, therefore, the process of determining whether or not the abnormal elapsed time counter C1 has increased beyond the waiting time α is repeated while monitoring whether the failed cylinder (exhaust valve) does not return spontaneously (step 214). 216). When the standby time α elapses when the failed exhaust valve does not return spontaneously, the determination in step 216 is established, so the variable valve mechanisms 34 and 36 are stopped, and the intake valves and exhaust valves of all the cylinders are stopped. Is stopped (step 218). In step 212, engine stop prohibition control is executed. If the exhaust valve naturally returns before the waiting time α elapses, the determination in step 214 is established, and the process returns without doing anything.

  On the other hand, if the determination in step 206 is not satisfied, it is determined whether or not a failure has occurred in all the cylinders because a valve return abnormality has occurred in the intake valve (step 220). When this determination is established, since the valve return abnormality of the intake valves has occurred in all the cylinders, the exhaust variable valve mechanism 36 is operated to stop the exhaust valves of all the cylinders (step 222). In step 212, engine stop prohibition control is executed. Further, when the determination in step 220 is not established, an abnormality in the return of the intake valve has occurred in some cylinders. Therefore, in this case, as in the case of the exhaust valve, it is determined whether or not the abnormal elapsed time counter C1 has increased beyond the waiting time β while monitoring whether or not the failed intake valve has returned spontaneously. The process is repeated (steps 224 and 226). When the standby time β has elapsed with the failed intake valve not returning spontaneously, the intake valves and exhaust valves of all the cylinders are stopped (step 228), and engine stop prohibition control is executed in step 212. . Also, if the intake valve naturally returns before the waiting time β has elapsed, the process returns without doing anything.

  Next, with reference to FIG. 7, a description will be given of the abnormality traveling control process executed in step 110 in FIG. 5. In the routine shown in FIG. 7, it is first determined whether or not the EV retreat travel mode is set (step 300). If this determination is not established, the EV travel time counter C2 is cleared to zero and the process returns as it is (step 302). The EV travel time counter C2 is a counter that measures an elapsed time from the start of the retreat travel. When the determination in step 300 is satisfied, counting by the EV travel time counter C2 is started (step 304).

  In the next process, it is determined whether or not the fixed cylinder (cylinder in which the valve return abnormality has occurred) has returned spontaneously (step 306). When this determination is established, the engine can be operated. Therefore, the stop of the intake valve and the exhaust valve is released, and these valves are driven in a normal state (step 308). Further, the EV retreat travel mode and the engine stop prohibition control are canceled (step 310). At this time, the fuel injection of the engine is also resumed. Further, as described above, in order to avoid the occurrence of the valve return abnormality again, the valve stop during the engine operation is prohibited (step 312). Then, the counters C1 and C2 are cleared to zero and the process returns (step 314).

  On the other hand, if the determination in step 306 is not established, the process of determining whether the EV travel time counter C2 has increased beyond the reference time γ is repeated while monitoring whether the valve of the fixed cylinder does not return spontaneously. (Step 316). When the determination in step 316 is satisfied, since the valve cannot be spontaneously restored even if the idling state of the engine continues further, stop of the engine is permitted (stop prohibition control is released), and the process returns (step 318).

  In the first embodiment, steps 206 to 210 and steps 214 to 222 in FIG. 6 show a specific example of the valve return abnormality handling means in claims 1 and 2. Steps 206, 208, and 220 are specific examples of the abnormal cylinder specifying means in claim 2, steps 210 and 222 are specific examples of the all cylinder abnormality response means in claim 2, and steps 214 to 218 and steps 224 to 228 are charged. Specific examples of the partial cylinder abnormality handling means in item 2 are shown. Steps 202 and 204 show a specific example of the retreat travel control means in claim 1, and step 212 shows a specific example of the engine idling control means in claim 1, respectively. Further, steps 308 and 310 in FIG. 7 are specific examples of the retreat travel stop means in claim 4, step 312 is a specific example of valve stop prohibiting means in claim 5, and steps 316 and 318 are idling stop means in claim 6. Each specific example is shown.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the same system configuration and control (FIGS. 1 to 6) as in the first embodiment are adopted, but the duration of the evacuation travel is limited. The configuration is different from that of Form 1. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[Features of Embodiment 2]
In the present embodiment, the variable valve mechanisms 34 and 36 return the intake valve 30 and the exhaust valve 32 when the evacuation running duration exceeds a predetermined time limit L in a state where the valve return abnormality is not recovered. At the same time, the EV evacuation travel is terminated. Thereby, the cranking load at the time of restart can be reduced and startability can be improved.

[Specific Processing for Realizing Embodiment 2]
FIG. 8 is a flowchart of control executed by the ECU in the second embodiment of the present invention. In the present embodiment, the routine shown in FIGS. 5 and 6 is executed as in the first embodiment, and the routine shown in FIG. 8 is executed instead of the routine shown in FIG. In the routine shown in FIG. 8, the same step numbers are assigned to the same processes as those in the first embodiment.

  As shown in FIG. 8, in the present embodiment, whether or not the EV travel time counter C2 has increased beyond a predetermined time limit L is monitored while monitoring whether or not the valve of the fixed cylinder does not return spontaneously at step 306. The determination process is repeated (step 316 ′). When the determination in step 316 ′ is established, steps 308 to 314 are executed to cancel the valve stop of the intake valve and the exhaust valve, the EV retreat travel mode, and the engine stop prohibition control. Step 316 'shows a specific example of the retreat travel restricting means in claim 8.

10 Engine (Internal combustion engine)
16 Crankshaft 30 Intake valve 32 Exhaust valve 34 Intake variable valve mechanism 36 Exhaust variable valve mechanism 38 Crank angle sensor 40 ECU
50 Vehicle 52 Electric motor (auxiliary power mechanism)
54 Power split mechanism (auxiliary power mechanism)
56 Transmission mechanism 58 Wheel

Claims (8)

An internal combustion engine equipped with a plurality of cylinders having an intake valve and an exhaust valve;
An auxiliary power mechanism constituting a power source together with the internal combustion engine;
A variable valve mechanism on the intake side that simultaneously stops and returns the intake valves of all cylinders;
A variable valve mechanism on the exhaust side that stops and resets the exhaust valves of all cylinders simultaneously,
Even when an operation of returning the intake valve and the exhaust valve by the variable valve mechanism is performed, when a valve return abnormality occurs in which one of the intake valve and the exhaust valve does not return, Valve return abnormality response means for stopping the other valve in which the valve return abnormality has not occurred while holding the one valve in a state in which the one valve can be naturally returned by a variable valve mechanism;
Retreat travel control means for stopping fuel injection of the internal combustion engine and performing retreat travel by the driving force of the auxiliary power mechanism when the valve return abnormality occurs;
An engine that, when the valve return abnormality occurs, causes the internal combustion engine to idle in a state where the self-sustained operation is stopped using the driving force of the auxiliary power mechanism while maintaining the one valve in a state where it can be naturally returned Idling control means,
A control device for an internal combustion engine and an auxiliary power mechanism. The valve return abnormality handling means is
An abnormal cylinder specifying means for specifying a cylinder in which the valve return abnormality of the one valve has occurred based on the operation information of the internal combustion engine;
All-cylinder abnormality response means for immediately stopping the valve when the valve return abnormality of the one valve occurs in all cylinders;
When a valve return abnormality of the one valve occurs in some cylinders, both the exhaust valve and the intake valve are stopped after a predetermined standby time has elapsed, and the valve return is performed during the standby time. A partial cylinder abnormality countermeasure means that does not stop the valve when the abnormality recovers;
The control apparatus for an internal combustion engine and an auxiliary power mechanism according to claim 1, comprising:   The standby time is composed of a first standby time used when the exhaust valve returns abnormally and a second standby time used when the intake valve returns abnormally, and the first standby time is the second standby time. The control device for an internal combustion engine and an auxiliary power mechanism according to claim 2, wherein the control device is set shorter than the standby time.   4. The retreat travel control means comprises retreat travel stop means for stopping the retreat travel and restarting the operation of the internal combustion engine when the valve return abnormality is recovered. A control device for an internal combustion engine and an auxiliary power mechanism according to the item.   5. The valve stop prohibiting means for prohibiting the intake valve and the exhaust valve from being stopped again by the variable valve mechanism when the valve return abnormality is recovered. The control device for an internal combustion engine and an auxiliary power mechanism according to claim 1.   2. An idling stop means for interrupting power transmission from the auxiliary power mechanism to the internal combustion engine when the duration of the retreat travel exceeds a predetermined reference time in a state where the valve return abnormality is not recovered. The control apparatus for an internal combustion engine and an auxiliary power mechanism according to any one of 1 to 5.   The internal combustion engine according to claim 6, wherein the reference time is set according to a time from when the idling of the internal combustion engine is started until the amount of lubricating oil sucked into the cylinder reaches an allowable limit. Power mechanism control device. If the duration of the evacuation travel in a state where the valve return abnormality is not recovered exceeds a predetermined time limit, The rewritable release valve stop of that due to the variable valve mechanism wherein the intake valve and the exhaust valve, The control device for an internal combustion engine and an auxiliary power mechanism according to any one of claims 1 to 7, further comprising a retreat travel restriction unit that terminates the retreat travel.

Images