JP2009068374A - Control device of internal combustion engine, control method, program for achieving the method with computer, and recording medium recording the program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately perform abnormality determination of a valve timing variable mechanism. <P>SOLUTION: An engine ECU executes a program including a step (S102) executing OBD processing when the executing condition of the OBD processing of the valve timing variable mechanism is approved (YES in S100), a step (S104) guarding a lead angle command value by a lower limit at 7°C CA and more, and a step (S108) releasing the lower limit guard of the lead angle command value when the OBD processing is finished (YES in S106). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to control of an internal combustion engine provided with a variable valve timing mechanism that changes the valve closing timing of an intake valve so that the compression pressure in a cylinder is reduced when the internal combustion engine is started. It is related with the technique which carries out appropriately.

  The combustion cycle of an internal combustion engine includes an Atkinson (Miller) cycle in which the expansion stroke is made longer than the compression process and energy is efficiently extracted. In such an Atkinson cycle, the intake valve is closed at a crank angle significantly slower than the bottom dead center.

  In addition, an internal combustion engine having a mechanism that develops an action (decompression action) for reducing the compression pressure in the cylinder in order to reduce the cranking force when cranking with a starter when the internal combustion engine is started is known.

  As such an internal combustion engine, for example, Japanese Patent Laid-Open No. 2002-61522 (Patent Document 1) reduces the vibration when the internal combustion engine is automatically started by a decompression action, and at the first explosion at a low rotational speed. A control device for a vehicle internal combustion engine is disclosed. A control device for an internal combustion engine for a vehicle includes a lift / working angle variable mechanism capable of simultaneously and continuously expanding and reducing the lift / working angle of the intake valve, and a phase for delaying the phase of the center angle of the lift of the intake valve Variable mechanism, means for detecting rotational speed and load of internal combustion engine, control means for controlling lift / operating angle and central angle of intake valve according to engine rotational speed and load, and motor for rotationally driving internal combustion engine The ignition operation of the internal combustion engine is stopped when the vehicle is stopped, and the ignition operation is restarted by starting the internal combustion engine by the motor when the vehicle starts. The control device for an internal combustion engine for a vehicle controls the lift / operating angle of the intake valve to a predetermined value or less and controls the central angle of the intake valve to the advance side immediately before the internal combustion engine stops when the vehicle stops. It is characterized by.

According to the control device for a vehicle internal combustion engine disclosed in the above-mentioned publication, in a vehicle internal combustion engine that is automatically stopped and restarted, such as a hybrid vehicle or a vehicle equipped with idle stop means, A so-called decompression action can be obtained, and unpleasant vibrations can be avoided, and the activation of the in-cylinder gas flow leads to the first explosion at a low rotational speed, thus ensuring good starting performance.
JP 2002-61522 A

  However, in a configuration in which the advanced valve closing timing is changed with the valve timing varying mechanism as the starting point, the abnormality in the valve timing varying mechanism cannot be accurately determined near the most retarded angle. There is a problem.

  This is because in order to accurately determine the abnormality of the variable valve timing mechanism, it is necessary to carry out the operation within a range in which the variable valve timing mechanism operates reliably. In the vicinity of the most retarded angle, the amount of change from the valve closing timing of the most retarded angle that is the starting point is small, and even if an abnormality has occurred, the abnormality cannot be accurately determined.

Especially in an internal combustion engine mounted on a hybrid vehicle and operated in the Atkinson cycle, it is frequently operated in the vicinity of the most retarded angle with a high fuel consumption rate, so it is possible to accurately determine abnormality of the variable valve timing mechanism. I can't.

  Further, the control device for an internal combustion engine for a vehicle disclosed in the above-mentioned publication does not consider such a problem at all.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize an internal combustion engine control device, a control method, and a method for appropriately performing abnormality determination of a variable valve timing mechanism with a computer. Program and a recording medium on which the program is recorded.

  An internal combustion engine control apparatus according to a first aspect of the invention is provided with a variable valve timing mechanism that changes a valve closing timing of an intake valve based on a command value so that a compression pressure in a cylinder is reduced when the internal combustion engine is started. It is an engine control device. The valve timing variable mechanism changes the valve closing timing to the advance side based on the command value, starting from the most retarded valve closing timing. The control device performs a predetermined execution for performing abnormality determination processing of the valve timing variable mechanism based on the means for detecting the physical quantity corresponding to the closing timing of the intake valve, and the detected physical quantity and the command value. Means for determining whether or not the condition is satisfied, means for executing abnormality determination processing based on the physical quantity and the command value detected when the execution condition is satisfied, and the command value of the command value when the execution condition is satisfied Limiting means for limiting the change of the valve closing timing to the retard side. An internal combustion engine control method according to a seventh aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the first aspect of the invention.

  According to the first invention, when the execution condition is satisfied, the change of the valve closing timing to the retard side of the command value is limited, and therefore the intake valve closing timing is changed to the most retarded valve closing timing. Is suppressed. Therefore, it is possible to determine whether or not the valve closing timing corresponding to the command value is different from the actual valve closing timing while the variable valve timing mechanism is operating reliably. Thereby, it is possible to accurately determine whether or not the variable valve timing mechanism is abnormal. Further, when the execution condition is not satisfied, the change of the valve closing timing to the retarded angle side is not limited, so that the internal combustion engine can be operated in the operation region where the fuel consumption rate is high. Therefore, it is possible to provide a control device and a control method for an internal combustion engine that can appropriately perform abnormality determination of the variable valve timing mechanism.

  The control apparatus for an internal combustion engine according to the second invention further includes means for releasing the restriction on the change of the valve closing timing when the abnormality determination process is completed, in addition to the configuration of the first invention. An internal combustion engine control method according to an eighth aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the second aspect of the invention.

  According to the second invention, when the abnormality determination process ends, the restriction on the change of the valve closing timing is released. Accordingly, for example, when it is determined that the variable valve timing mechanism is normal, the change of the valve closing timing to the retarded angle side is not limited, so that the internal combustion engine can be operated in an operating region with a high fuel consumption rate.

  In the control apparatus for an internal combustion engine according to the third invention, in addition to the configuration of the first or second invention, the execution condition is determined in advance from a command value corresponding to the valve closing timing at which the command value is the most retarded angle. The condition that the first value or more is the advance side and the condition that the difference between the valve closing timing corresponding to the command value and the valve closing timing corresponding to the detected physical quantity is equal to or greater than a predetermined second value. It is. An internal combustion engine control method according to a ninth aspect has the same configuration as the control apparatus for an internal combustion engine according to the third aspect.

According to the third aspect of the invention, the variable valve timing mechanism operates reliably under the condition that the command value is advanced from the command value corresponding to the most retarded valve closing timing by a predetermined first value or more. The abnormality determination process can be performed within the range. Further, the valve closing timing corresponding to the command value and the detected valve closing timing are determined under the condition that the difference between the valve closing timing corresponding to the command value and the detected valve closing timing is equal to or greater than a predetermined second value. It can be determined whether or not the time is in a state of deviating. Therefore, by restricting the change of the command value to the retard side when these execution conditions are satisfied, it is possible to accurately determine whether or not the valve timing variable mechanism is abnormal.

  In the control apparatus for an internal combustion engine according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the limiting means is predetermined from a command value corresponding to the most retarded valve closing timing. Means for setting the command value advanced to the advance side by the value as the lower limit value is included. An internal combustion engine control method according to a tenth aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the fourth aspect of the invention.

  According to the fourth invention, when the execution condition is satisfied, the valve closing timing is controlled with the command value advanced from the command value corresponding to the most delayed valve closing timing by a predetermined value to the advance side as the lower limit value. Therefore, it is suppressed that the closing timing of the intake valve is changed to the most retarded closing timing. Therefore, it is possible to determine whether or not the valve closing timing corresponding to the command value is different from the actual valve closing timing while the variable valve timing mechanism is operating reliably. Thereby, it is possible to accurately determine whether or not the variable valve timing mechanism is abnormal.

  In the control device for an internal combustion engine according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the variable valve timing mechanism sets the valve closing timing based on the command value when the internal combustion engine is stopped. Change to the retarded angle side from the piston bottom dead center. An internal combustion engine control method according to an eleventh aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the fifth aspect of the invention.

  According to the fifth invention, since the closing timing of the intake valve is changed to the retard side with respect to the intake bottom dead center of the piston when the internal combustion engine is stopped, the closed valve is changed to the retard side when the internal combustion engine is started. It will be started at the time. Therefore, a part of the air (or mixture) sucked in the intake stroke is returned to the intake passage after the piston starts to rise until the valve closing timing, so that the compression pressure is reduced when the internal combustion engine is started. Will be. Thereby, the vibration generated at the time of starting can be reduced.

  In the control apparatus for an internal combustion engine according to the sixth aspect of the invention, in addition to the configuration of any one of the first to fifth aspects, the variable valve timing mechanism sets the valve closing timing based on the command value after starting the internal combustion engine. Change to the retarded angle side of the intake bottom dead center. An internal combustion engine control method according to a twelfth aspect of the invention has a configuration similar to that of the control device for an internal combustion engine according to the sixth aspect of the invention.

  According to the sixth aspect of the present invention, when the closing timing of the intake valve is changed to the retard side after the internal combustion engine is started, the internal combustion engine can be operated in an operating region where the fuel efficiency is good.

  A program according to a thirteenth invention is a program for realizing the control method for an internal combustion engine according to any one of the seventh to twelfth inventions by a computer, and the recording medium according to the fourteenth invention is a seventh to twelfth recording medium. A medium having recorded thereon a computer-implemented method for controlling an internal combustion engine according to any one of the inventions.

  According to the thirteenth or fourteenth invention, the control method for an internal combustion engine according to any one of the seventh to twelfth inventions can be realized using a computer (which may be general purpose or dedicated).

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A control block diagram of a hybrid vehicle to which a control device according to an embodiment of the present invention is applied will be described with reference to FIG.

  The hybrid vehicle includes an internal combustion engine (hereinafter simply referred to as an engine) 120 such as, for example, a gasoline engine or a diesel engine, and a motor generator (MG) 140 that is a rotating electric machine as drive sources. In FIG. 1, for convenience of explanation, the motor generator 140 is expressed as a motor 140A and a generator 140B (or a motor generator 140B). However, depending on the traveling state of the hybrid vehicle, the motor 140A functions as a generator, The generator 140B functions as a motor.

  In the intake passage 122 of the engine 120, an air cleaner 122A that captures dust of intake air, an air flow meter 122B that detects the amount of air sucked into the engine 120 through the air cleaner 122A, and an amount of air sucked into the engine 120 are adjusted. For this purpose, an electronic throttle valve 122C is provided. The electronic throttle valve 122C is provided with a throttle position sensor. An engine ECU (Electronic Control Unit) 280 receives an intake air amount detected by an air flow meter 122B, an opening degree of an electronic throttle valve 122C detected by a throttle position sensor, and the like.

  Engine 120 is provided with a plurality of cylinders and a fuel injection device 130 that injects fuel into each cylinder. The fuel injection device 130 injects an appropriate amount of fuel to each cylinder at an appropriate time based on a fuel injection control signal from the engine ECU 280.

  Further, in the exhaust passage 124 of the engine 120, a three-way catalytic converter 124B, an air-fuel ratio sensor 124A for detecting an air-fuel ratio (A / F) in the exhaust gas introduced into the three-way catalytic converter 124B, and a three-way catalytic converter 124B. A catalyst temperature sensor 124C for detecting the temperature of the catalyst and a silencer 124D are provided. The engine ECU 280 receives the air-fuel ratio of the exhaust gas introduced into the three-way catalytic converter 124B detected by the air-fuel ratio sensor 124A, the temperature of the three-way catalytic converter 124B detected by the catalyst temperature sensor 124C, and the like. The air-fuel ratio sensor 124A may be an O2 sensor.

  Engine ECU 280 also receives a signal indicating the engine cooling water temperature from water temperature detection sensor 360 that detects the temperature of the cooling water of engine 120. A crank position sensor 380 is provided on the output shaft of the engine 120, and a signal indicating the rotation speed of the output shaft is input from the crank position sensor 380 to the engine ECU 280.

In addition to this, the hybrid vehicle transmits a power generated by the engine 120 and the motor generator 140 to the drive wheels 160, and a reduction gear 180 that transmits the drive of the drive wheels 160 to the engine 120 and the motor generator 140, and the engine 120. Power split mechanism (for example, planetary gear mechanism) 200 that distributes the generated power to two paths of drive wheel 160 and generator 140B, travel battery 220 that charges power for driving motor generator 140, and travel Inverter 240 that performs current control while converting the direct current of battery 220 for the motor and the alternating current of motor 140A and generator 140B, and a battery control unit (hereinafter referred to as a battery ECU) 260 that manages and controls the charge / discharge state of battery for traveling 220 , Operating state of engine 120 The engine ECU 280 to be controlled, the MG-ECU 300 for controlling the motor generator 140, the battery ECU 260, the inverter 240, etc. according to the state of the hybrid vehicle, and the battery ECU 260, the engine ECU 280, the MG-ECU 300, etc. It includes an HV-ECU 320 that controls the entire hybrid system so that the vehicle can operate most efficiently. In addition, a power storage mechanism such as a capacitor may be used instead of the traveling battery.

  In the present embodiment, converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of the traveling battery 220 is lower than the rated voltage of the motor 140A or the motor generator 140B, and therefore when the power is supplied from the traveling battery 220 to the motor 140A or the motor generator 140B, the converter 242 boosts the power. To do. This converter 242 has a built-in smoothing capacitor, and when the converter 242 performs a boosting operation, electric charge is stored in this smoothing capacitor.

  In FIG. 1, each ECU is configured separately, but may be configured as an ECU in which two or more ECUs are integrated (for example, MG-ECU 300 and HV as shown by a dotted line in FIG. 1). -An example is an ECU integrated with the ECU 320).

  The driver's seat is provided with an accelerator pedal (not shown), and the accelerator position sensor 330 detects the amount of depression of the accelerator pedal. The accelerator position sensor 330 outputs a signal indicating the amount of depression of the accelerator pedal to the HV-ECU 320. The HV-ECU 320 controls the output of the engine 120 or the power generation amount via the motor 140A, the generator 140B, and the engine ECU 280 according to the required driving force corresponding to the depression amount.

  The power split mechanism 200 uses a planetary gear mechanism (planetary gear) in order to distribute the power of the engine 120 to both the drive wheel 160 and the motor generator 140B. By controlling the rotation speed of motor generator 140B, power split device 200 also functions as a continuously variable transmission.

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, the hybrid vehicle travels only by the motor 140 </ b> A of the motor generator 140 when the engine 120 is inefficient, such as when starting or running at a low speed. During normal travel, for example, the power split mechanism 200 divides the power of the engine 120 into two paths, and on the other hand, the drive wheels 160 are directly driven, and on the other hand, the generator 140B is driven to generate power. At this time, the motor 140A is driven by the generated electric power to assist driving of the driving wheels 160. Further, at the time of high speed traveling, electric power from the traveling battery 220 is further supplied to the motor 140A to increase the output of the motor 140A and to add driving force to the driving wheels 160.

  On the other hand, at the time of deceleration, motor 140 </ b> A driven by drive wheel 160 functions as a generator to perform regenerative power generation, and the collected power is stored in traveling battery 220. When the amount of charge of traveling battery 220 decreases and charging is particularly necessary, the output of engine 120 is increased to increase the amount of power generated by generator 140B to increase the amount of charge for traveling battery 220. Of course, there is a case where control is performed to increase the driving force of the engine 120 as necessary even during low-speed traveling. For example, it is necessary to charge the traveling battery 220 as described above, to drive an auxiliary machine such as an air conditioner, or to raise the temperature of the cooling water of the engine 120 to a predetermined temperature.

Furthermore, in a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, engine 120 is stopped in order to improve fuel consumption depending on the driving state of the vehicle and the state of traveling battery 220. And after that, the driving | running state of the vehicle and the state of the battery 220 for driving | running | working are detected, and the engine 120 is restarted. Thus, the engine 120 is intermittently operated, and in a conventional vehicle (a vehicle equipped with only an engine), when the ignition switch is turned to the START position and the engine is started, the ignition switch is switched from the ON position to the ACC position. Or it is different in that the engine does not stop until it is in the OFF position.

  With reference to FIG. 2, engine 120 of a vehicle equipped with the control device according to the present embodiment will be described. The control device according to the present embodiment is realized, for example, by executing a program recorded in ROM (Read Only Memory) 282 of engine ECU 280 shown in FIG. The program executed by engine ECU 280 may be recorded on a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc) and distributed to the market. Engine ECU 280 may be divided into a plurality of ECUs.

  Engine 120 according to the present embodiment is driven by alcohol fuel. Air is sucked into engine 120 from air cleaner 122A. The intake air amount is adjusted by the throttle valve 122C. The throttle valve 122C is an electrically controlled throttle valve that is driven by a motor.

  Air is mixed with alcohol fuel in a cylinder 1060 (combustion chamber). Alcohol fuel is injected from the injector 130. Note that alcohol fuel may be directly injected into the cylinder 1060.

  The air-fuel mixture in the cylinder 1060 is ignited by the spark plug 1100 and burned. The air-fuel mixture after combustion, that is, the exhaust gas is purified by the three-way catalyst 124B and then discharged outside the vehicle. The piston 1140 is pushed down by the combustion of the air-fuel mixture, and the crankshaft 1160 rotates.

  An intake valve 1180 and an exhaust valve 1200 are provided at the top of the cylinder 1060. The amount and timing of air introduced into the cylinder 1060 are controlled by the intake valve 1180. The amount and timing of exhaust discharged from the cylinder 1060 are controlled by an exhaust valve 1200. Intake valve 1180 is driven by cam 1220. The exhaust valve 1200 is driven by a cam 1240.

  Opening and closing timing of intake valve 1180 is controlled by variable valve timing mechanism 1260. In the present embodiment, the phase difference between the camshaft and the crankshaft 1160 is changed by rotating the camshaft on which the cam 1220 is provided by the variable valve timing mechanism 1260 to the retard side or the advance side, and the intake air The opening / closing timing of the valve 1180 is changed. The variable valve timing mechanism 1260 is operated by, for example, a hydraulic pressure or an electric motor. However, a well-known general technique may be used, and detailed description thereof will not be given here.

  In the present embodiment, variable valve timing mechanism 1260 starts engine 120 when the camshaft phase angle, that is, the closing timing of intake valve 1180 is the most retarded angle. For example, engine ECU 280 controls variable valve timing mechanism 1260 so that the closing timing of intake valve 1180 becomes the most retarded angle on the retard side with respect to the intake bottom dead center of piston 1140 when engine 120 is stopped.

  In this way, when the engine 120 is started, a part of the air (or mixture) sucked in the intake stroke is returned to the intake passage 122 between the start of the piston 1140 rising and the valve closing timing. Therefore, the compression pressure is reduced when the engine 120 is started. That is, a decompression effect is obtained. Thereby, the vibration generated at the time of starting can be reduced.

  Further, in the present embodiment, valve timing varying mechanism 1260 changes the closing timing of intake valve 1180 to the retard side from the intake bottom dead center of piston 1140 after engine 120 is started. In this way, engine 120 can operate in an Atkinson cycle. Therefore, engine 120 can be operated in an operating region where the fuel efficiency is good.

  The cam angle sensor 382 is opposed to convex teeth formed at predetermined intervals along the rotational direction of a timing rotor (not shown) fixed to the camshaft on which the cam 1220 is provided. Provided. In response to the rotation of the timing rotor, the cam angle sensor 382 outputs a signal indicating the rotational position of the cam 1220. Specifically, cam angle sensor 382 outputs to engine ECU 280 a signal corresponding to a change in the air gap between the teeth provided on the timing rotor and cam angle sensor 382.

  The crank angle sensor 380 is provided so as to face the timing rotor 1110 fixed to the crankshaft 1160. The timing rotor 1110 is formed with a plurality of convex teeth along the rotation direction. The plurality of tooth portions are provided at predetermined intervals. Crank angle sensor 380 is constituted by, for example, a coil or the like, and when timing rotor 1110 rotates, crank angle sensor 380 outputs a signal corresponding to an air gap with a plurality of tooth portions to engine ECU 280.

  Further, the timing rotor 1110 has a missing tooth at a predetermined position. Engine ECU 280 detects the rotation angle and rotation speed (engine rotation speed) of crankshaft 1160 using the position of the missing tooth detected by crank angle sensor 380 as a reference position.

  Further, engine ECU 280 calculates an actual valve closing timing (hereinafter, an actual advance angle value) based on the cam angle received from cam angle sensor 382 and the engine speed received from crank angle sensor 380. For example, engine ECU 280 detects the actual advance value based on the phase of the rotation of cam 1220 and the rotation of crankshaft 1160 with the position of the missing tooth formed on timing rotor 1110 as the reference position.

  Knock sensor 362 outputs a signal representing the intensity of vibration of engine 120. The throttle opening sensor 122D outputs a signal representing the throttle opening. Air flow meter 122B outputs a signal representing the amount of air taken into engine 120. Air-fuel ratio sensor 124B outputs a signal representing the air-fuel ratio of the exhaust.

  As described above, signals are input to engine ECU 280 from cam angle sensor 382, crank angle sensor 380, water temperature sensor 360, knock sensor 362, throttle opening sensor 122D, air flow meter 122B, air-fuel ratio sensor 124A, and the like. The

  Engine ECU 280 controls engine 120 based on signals input from these sensors, a map stored in ROM 282, and a program. Specifically, engine ECU 280 controls the throttle opening, ignition timing, fuel injection timing, fuel injection amount, and operation state (opening / closing timing, etc.) of intake valve 1180 so that engine 120 is in a desired operating state. .

In the present embodiment, engine ECU 280 determines the opening / closing timing of intake valve 1180 (hereinafter also referred to as an advance angle command value) at which the fuel efficiency is optimal in accordance with the required power to engine 120 calculated from the accelerator opening or the like. decide. Engine ECU 280 transmits an advance angle control signal corresponding to the determined advance angle command value to valve timing variable mechanism 1260. In the present embodiment, description will be made assuming that the advance angle command value when the valve closing timing of intake valve 1180 is the most retarded angle is zero, but the present invention is not particularly limited to this.

  Further, engine ECU 280 determines whether or not valve timing variable mechanism 1260 is abnormal based on the determined advance angle command value and the detected actual advance value (hereinafter referred to as abnormality determination process or OBD ( It is determined whether or not a predetermined execution condition for executing On Board Diagnosis processing) is satisfied, and if the execution condition is satisfied, the OBD processing is executed.

  The present invention is characterized in that the engine ECU 280 restricts the change of the advance command value to the retard side when the execution condition is satisfied. Specifically, when the execution condition is satisfied, engine ECU 280 sets, as a lower limit value, an advance angle command value that is advanced by a predetermined value from an advance angle command value corresponding to the most retarded valve closing timing. To do. Further, engine ECU 280 releases the restriction on the change of the valve closing timing when the OBD process is completed.

  In the present embodiment, the “predetermined execution condition” is a condition that the advance angle command value is an advance side greater than a predetermined value A from the advance angle command value corresponding to the most retarded valve closing timing. And the difference between the advance angle command value and the actual advance angle value is equal to or greater than a predetermined value B. In the present embodiment, it is assumed that the advance command value is a value on the advance side.

  In the present embodiment, it is assumed that the predetermined value A and the predetermined value B are both 5 ° CA. However, it is determined that the valve timing variable mechanism 1260 is operating reliably. The value is not particularly limited as long as it is a possible value, and the predetermined value A and the predetermined value B may be different values. In the present embodiment, the “lower limit value” is described as being 7 ° CA. However, it may be a value including an error with respect to the predetermined value A or the predetermined value B, The invention is not particularly limited to this.

  FIG. 3 shows a functional block diagram of engine ECU 280 which is the control device for the internal combustion engine according to the present embodiment.

  Engine ECU 280 includes an input interface (hereinafter referred to as an input I / F) 350, an arithmetic processing unit 400, a storage unit 500, and an output interface (hereinafter referred to as an output I / F) 600.

  The input I / F 350 receives the cam angle signal from the cam angle sensor 382 and the engine speed signal from the crank angle sensor 380 and transmits them to the arithmetic processing unit 400.

  Arithmetic processing unit 400 includes an execution condition determination unit 402, an OBD processing unit 404, an end determination unit 406, a lower limit guard setting unit 408, and a lower limit guard release unit 410.

  The execution condition determination unit 402 determines whether an execution condition is satisfied. More specifically, the execution condition determination unit 402 says that the advance angle command value is greater than or equal to a predetermined value A and that the advance angle command value−actual advance angle value is greater than or equal to a predetermined value B. It is determined whether or not both conditions are satisfied. Since the calculation method of the advance angle command value and the actual advance angle value is as described above, detailed description thereof will not be repeated. The execution condition determination unit 402 turns on the OBD execution determination flag when the execution condition is satisfied.

  The OBD processing unit 404 executes the OBD process when the execution condition is satisfied. The OBD processing unit 404 determines whether or not the advance angle command value and the actual advance angle value are greatly deviated. For example, the OBD processing unit 404 sets the valve when the state that the advance command value−actual advance value is equal to or greater than a predetermined value (for example, 5 ° CA) continues until a predetermined time elapses. It may be determined that the timing variable mechanism 1260 is in an abnormal state.

  Note that the OBD processing unit 404 may execute the OBD processing when the OBD execution determination flag is on, for example. For example, when the OBD processing unit 404 determines that the variable valve timing mechanism 1260 is abnormal, the OBD processing unit 404 may turn on the abnormality determination flag.

  The end determination unit 406 determines whether to end the OBD process. Specifically, when it is determined by the OBD process that the valve timing variable mechanism 1260 is normal or abnormal, the end determination unit 406 determines to end the OBD process. Alternatively, the end determination unit 406 determines to end the OBD process when the execution condition is not satisfied. In addition, for example, the end determination unit 406 may start the determination when the OBD execution determination flag is turned on and turn off the OBD execution determination flag when it is determined that the OBD processing is ended.

  The lower limit guard setting unit 408 sets the lower limit value of the advance command value when the execution condition is satisfied. Therefore, the advance command value calculated according to the required power based on the accelerator opening is at least 7 ° CA or more. Note that the lower limit guard setting unit 408 may set the lower limit value of the advance command value when the OBD execution determination flag is on, for example.

  The lower limit guard canceling unit 410 cancels the setting of the lower limit value of the advance angle command value when the OBD process ends. Note that the lower limit guard canceling unit 410 may cancel the setting of the lower limit value when the OBD execution determination flag is off, for example.

  In the present embodiment, the execution condition determination unit 402, the OBD processing unit 404, the end determination unit 406, the lower limit guard setting unit 408, and the lower limit guard release unit 410 are all arithmetic processing units 400. Although a description will be given assuming that a CPU (Central Processing Unit) functions as software realized by executing a program stored in the storage unit 500, it may be realized by hardware. Such a program is recorded on a storage medium and mounted on the vehicle.

  Various information, programs, threshold values, maps, and the like are stored in the storage unit 500, and data is read or stored from the arithmetic processing unit 400 as necessary.

  Hereinafter, with reference to FIG. 4, a control structure of a program executed by engine ECU 280 which is the control device for the internal combustion engine according to the present embodiment will be described.

  In step (hereinafter, step is referred to as S) 100, engine ECU 280 determines whether or not an execution condition for the OBD process is satisfied. If the execution condition is satisfied (YES in S100), the process proceeds to S102. Otherwise (NO in S100), this process ends.

  In S102, engine ECU 280 executes an OBD process. In S104, engine ECU 280 performs a lower limit guard so that the advance angle command value becomes 7 ° CA or more. That is, engine ECU 280 sets 7 ° CA as the lower limit value.

  In S106, engine ECU 280 performs an end determination of the OBD process. When the OBD process ends (YES in S106), the process proceeds to S106. If not (NO in S106), the process returns to S102. In S108, engine ECU 280 releases the lower limit guard for the advance command value.

The operation of engine ECU 280, which is the vehicle control apparatus according to the present embodiment, based on the above-described structure and flowchart will be described with reference to FIG.

  For example, assume that the actual advance value and the advance command value are zero, such as immediately after the engine 120 is started.

  When the required power for the engine 120 varies in accordance with the amount of depression of the accelerator pedal by the driver, the advance angle command value increases to A (2) and A (1) as shown by the solid line in FIG. Go. On the other hand, when the valve timing variable mechanism 1260 is abnormal and cannot be operated, the actual advance value continues to be zero.

  Since the actual advance value is zero when the advance command value becomes A (3) of 5 ° CA or more at time T (0), the advance command value−actual advance value is also 5 ° CA. Thus, the execution condition is satisfied (YES in S100). Therefore, as shown in FIG. 5, the OBD execution determination flag is turned on and the OBD process is executed (S102). At this time, 7 ° CA is set as the lower limit value of the advance command value (S104).

  After time T (0), when the advance angle command value determined according to the driving state of the vehicle is A (0) larger than 7 ° CA, the valve is set with A (0) as the advance angle command value. A control signal is output to the timing variable mechanism 1260.

  When the lower limit value is not set at time T (1), A (3) smaller than 7 ° CA is determined as the advance command value according to the driving state of the vehicle, as shown by the broken line in FIG. However, when the lower limit value is set, 7 ° CA is determined as the advance command value as shown by the solid line in FIG.

  When the lower limit value is not set at time T (2) and time T (3) after time T (1), as shown by the broken line in FIG. 5, the advance angle command value depends on the driving state of the vehicle. A (1) and A (2) smaller than 7 ° CA are respectively determined, but since the lower limit is set, the lower limit 7 ° CA is advanced as shown by the solid line in FIG. It is determined as a command value.

  As shown by the broken line in FIG. 5, when the lower limit value is not set, the OBD execution determination flag is turned off after time T (2), so that the OBD process is performed even though the actual advance value is abnormal. Not executed.

  On the other hand, when the lower limit value is set, as shown by the solid line in FIG. 5, the state where the OBD execution determination flag is on is continued after time T (2). Therefore, in the OBD process, if the state in which the advance angle command value and the actual advance angle value greatly deviate continues until a predetermined time elapses, it is determined that the valve timing variable mechanism 1260 is abnormal.

  When the OBD process is completed (YES in S106), the lower limit guard for the advance command value is released (S108).

As described above, according to the control apparatus for an internal combustion engine according to the present embodiment, when the execution condition is satisfied, the lower limit value of the advance command value is set, so that the closing timing of the intake valve is the most delayed closing time. The change until the valve timing is suppressed. Therefore, it is possible to determine whether or not the advance angle command value is deviated from the actual advance angle value while the variable valve timing mechanism is operating reliably. Thereby, it is possible to accurately determine whether or not the variable valve timing mechanism is abnormal. Further, when the execution condition is not satisfied, the change of the valve closing timing to the retarded angle side is not limited, so that the internal combustion engine can be operated in the operation region where the fuel consumption rate is high. Therefore, it is possible to provide an internal combustion engine control apparatus, a control method, a program that implements the method using a computer, and a recording medium that records the program, which can appropriately perform abnormality determination of the variable valve timing mechanism.

  In the present embodiment, the case where the present invention is applied to an engine having a decompression action at the start and having an area operated in the Atkinson cycle after the start has been described. The present invention is not limited to such an engine, but may be applied to a known engine.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a control block diagram of a hybrid vehicle equipped with a control device for an internal combustion engine according to the present embodiment. It is a schematic block diagram of the engine mounted in the vehicle. It is a functional block diagram showing a configuration of an engine ECU that is a control device for an internal combustion engine according to the present embodiment. It is a flowchart which shows the control structure of the program performed by engine ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment. 3 is a timing chart showing an operation of an engine ECU which is a control device for an internal combustion engine according to the present embodiment.

Explanation of symbols

  120 engine, 122 intake passage, 122A air cleaner, 122B air flow meter, 122C electronic throttle valve, 124 exhaust passage, 124A air-fuel ratio sensor, 124B three-way catalytic converter, 124C catalyst temperature sensor, 124D silencer, 130 fuel injection device, 140 motor Generator, 140A motor, 140B generator, 160 drive wheel, 180 reducer, 200 power split mechanism, 220 battery for traveling, 240 inverter, 242 converter, 260 battery ECU, 280 engine ECU, 282 ROM, 300 MG-ECU, 320 HV -ECU, 330 accelerator position sensor, 350 input I / F, 360 water temperature sensor, 362 knock sensor, 380 crank angle sensor, 382 Angle sensor, 400 arithmetic processing unit, 402 execution condition determination unit, 404 OBD processing unit, 406 end determination unit, 408 lower limit guard setting unit, 410 lower limit guard release unit, 500 storage unit, 600 output I / F, 1060 cylinder, 1100 Spark plug, 1110 timing rotor, 1140 piston, 1160 crankshaft, 1180 intake valve, 1200 exhaust valve, 1220, 1240 cam, 1260 valve timing variable mechanism.

Claims (14)

A control device for an internal combustion engine provided with a variable valve timing mechanism for changing a valve closing timing of an intake valve based on a command value so that a compression pressure in a cylinder is reduced when the internal combustion engine is started. Is based on the command value to change the closing timing to the advance side starting from the most retarded closing timing,
Means for detecting a physical quantity corresponding to the closing timing of the intake valve;
Means for determining whether or not a predetermined execution condition for executing the abnormality determination processing of the valve timing variable mechanism is satisfied based on the detected physical quantity and the command value;
Means for executing the abnormality determination process based on the detected physical quantity and the command value when the execution condition is satisfied;
A control device for an internal combustion engine, including limiting means for limiting change of the valve closing timing of the command value to the retard side when the execution condition is satisfied.   2. The control device for an internal combustion engine according to claim 1, further comprising means for releasing a restriction on the change of the valve closing timing when the abnormality determination process is completed. 3. The execution condition is as follows:
A condition that the command value is an advance side of a predetermined value or more from a command value corresponding to the most retarded valve closing timing;
The internal combustion engine according to claim 1 or 2, wherein a difference between a valve closing timing corresponding to the command value and a valve closing timing corresponding to the detected physical quantity is equal to or greater than a predetermined second value. Engine control device.   The limiting means includes means for setting, as a lower limit value, a command value advanced from the command value corresponding to the most delayed valve closing timing by a predetermined value to the advance side. The control apparatus for an internal combustion engine according to any one of the above.   5. The variable valve timing mechanism according to claim 1, wherein, when the internal combustion engine is stopped, the valve closing timing is changed to a retarded angle side with respect to an intake bottom dead center of the piston based on the command value. Control device for internal combustion engine.   6. The variable valve timing mechanism according to claim 1, wherein, after starting the internal combustion engine, the valve closing timing is changed to a retarded angle side with respect to a piston bottom dead center based on the command value. Control device for internal combustion engine. A control method for an internal combustion engine provided with a variable valve timing mechanism for changing a valve closing timing of an intake valve based on a command value so that a compression pressure in a cylinder is lowered when the internal combustion engine is started. Is based on the command value to change the closing timing to the advance side starting from the most retarded closing timing,
Detecting a physical quantity corresponding to the closing timing of the intake valve;
Determining whether or not a predetermined execution condition for executing the abnormality determination processing of the valve timing variable mechanism is satisfied based on the detected physical quantity and the command value;
When the execution condition is satisfied, executing the abnormality determination process based on the detected physical quantity and the command value;
A control step for limiting the change of the valve closing timing of the command value to the retard side when the execution condition is satisfied.   The method for controlling an internal combustion engine according to claim 7, wherein the control method further includes a step of releasing the restriction on the change of the valve closing timing when the abnormality determination process is completed. The execution condition is as follows:
A condition that the command value is a command value on the advance side over a first value determined in advance from a command value corresponding to the most retarded valve closing timing;
The internal combustion engine according to claim 7 or 8, wherein a difference between a valve closing timing corresponding to the command value and a valve closing timing corresponding to the detected physical quantity is equal to or greater than a predetermined second value. Control method.   10. The method according to claim 7, wherein the limiting step includes a step of setting, as a lower limit value, a command value advanced from the command value corresponding to the most delayed valve closing timing by a predetermined value to the advance side. A control method for an internal combustion engine according to claim 1.   11. The variable valve timing mechanism according to claim 7, wherein when the internal combustion engine is stopped, the valve closing timing is changed to a retarded angle side with respect to an intake bottom dead center of the piston based on the command value. Control method for an internal combustion engine.   12. The variable valve timing mechanism according to claim 7, wherein the valve closing timing is changed to a retarded angle side with respect to an intake bottom dead center of the piston based on the command value after the internal combustion engine is started. A method for controlling an internal combustion engine.   The program which implement | achieves the control method of the internal combustion engine in any one of Claims 7-12 with a computer.   The recording medium which recorded the program which implement | achieves the control method of the internal combustion engine in any one of Claims 7-12 with a computer.

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