Control device for hybrid vehicle

Abstract

The present invention relates to a control device for a hybrid vehicle. The control device is capable of executing: an ignition timing calculation process for calculating a target ignition timing for a spark plug; a stop process for stopping combustion control for some of a plurality of cylinders; and a compensation process for controlling a motor generator during the stop process so that the motor generator compensates for driving power lost due to stopping combustion control. When the target ignition timing calculated in the ignition timing calculation process is delayed by a predetermined prescribed time, the control device prohibits execution of the stop process.

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid vehicle. Background Art

[0002] The vehicle disclosed in Japanese Unexamined Patent Application Publication No. 2009-248698 (JP 2009-248698 A) includes an internal combustion engine, a first motor generator, a second motor generator, a planetary gear mechanism, a drive shaft, drive wheels, and a control device. The internal combustion engine, the first motor generator, and the second motor generator are coupled via a planetary gear mechanism to enable transmission of dynamic power to each other. The planetary gear mechanism is coupled to the drive wheels via a drive shaft. The planetary gear mechanism transmits torque output by the internal combustion engine, the first motor generator, and the second motor generator to the drive wheels via the drive shaft.

[0003] A control device controls the internal combustion engine and the motor generator. Depending on the vehicle's driving conditions, the control device stops combustion of the air-fuel mixture in each cylinder of the internal combustion engine. In this case, to suppress torque shock in the drive shaft caused by the reduction in torque of the internal combustion engine, the control device causes the second motor generator to output a correction torque. In other words, the control device drives and controls the second motor generator to compensate for the reduction in torque of the internal combustion engine. Summary of the Invention

[0004] In the control of an internal combustion engine, when combustion of an air-fuel mixture is sequentially performed in all cylinders of the internal combustion engine, the torque of the internal combustion engine periodically increases in response to the combustion strokes of the cylinders. In some cases, combustion of the air-fuel mixture stops in only some of the cylinders of the internal combustion engine, while combustion of the air-fuel mixture continues in other cylinders at corresponding ignition timings. In this case, the torque of the internal combustion engine increases in response to the combustion strokes of the cylinders where combustion continues. On the other hand, the torque of the internal combustion engine significantly decreases during the combustion strokes of the cylinders where combustion stops.

[0005] When the internal combustion engine is controlled while combustion in some cylinders is stopped as described above, the technology of JP 2009-248698 A can be applied, and a correction torque can be output. In this case, to offset the reduction in the internal combustion engine's torque, the correction torque is output during the combustion stroke of the cylinder where combustion has stopped. While the output of the correction torque is repeated, when the ignition timing of the cylinder where combustion continues suddenly changes to the delayed side, the phase of the internal combustion engine's torque as a whole suddenly changes. At the same time, the peak moment of the reduction in the internal combustion engine's torque suddenly changes during the combustion stroke of the cylinder where combustion has stopped. In this case, a gap is created between the phase of the internal combustion engine's torque and the phase of the correction torque, making it impossible to properly offset the reduction in the internal combustion engine's torque.

[0006] A control device for a hybrid vehicle for solving the above-mentioned problem is the following control device for a hybrid vehicle, which includes an internal combustion engine and an electric generator as driving sources, the internal combustion engine including a plurality of cylinders and a spark plug for each cylinder, the internal combustion engine and the electric generator being connected to a drive shaft, and the control device being capable of performing: ignition timing calculation processing: calculating a target ignition timing of the spark plug; stop processing: stopping combustion control of some of the cylinders; and compensation processing: during the stop processing, controlling the electric generator so that the electric generator compensates for the driving power lost due to the stopping of the combustion control, and when the target ignition timing calculated in the ignition timing calculation processing is later than a predetermined prescribed time, the control device prohibits the execution of the stop processing.

[0007] In this configuration, execution of the stop process is prohibited when the target ignition timing is later than a specified time. In other words, the stop process is not executed if there is a risk that changes in engine torque caused by the stop process will not be compensated. This prevents the occurrence of vibrations and other issues caused by a failure to compensate for torque changes during the stop process.

[0008] When the torque of the internal combustion engine is equal to or lower than a predetermined prescribed torque during deceleration of the hybrid vehicle, the control apparatus for the hybrid vehicle may regard the target ignition timing as being later than the prescribed time and may prohibit execution of the stop process.

[0009] When the internal combustion engine torque becomes equal to or lower than a specified torque during deceleration of the hybrid vehicle, the target ignition timing is retarded to further reduce the engine torque. In other words, when the internal combustion engine torque becomes equal to or lower than the specified torque during deceleration, there is a possibility that the target ignition timing will become later than the specified time. By prohibiting execution of the stop process in this situation, the occurrence of vibrations and the like due to failure to compensate for torque variations can be prevented.

[0010] In a control device for a hybrid vehicle, the internal combustion engine may include a filter that captures particulate matter in the exhaust gas, and when conditions are satisfied including a condition that the accumulated amount of particulate matter in the filter is equal to or greater than a predetermined prescribed accumulated amount, the control device may be able to perform a filter regeneration process that removes the particulate matter captured in the filter, and during execution of the filter regeneration process, the control device may regard the target ignition timing as being later than the prescribed time and may prohibit execution of the stop process.

[0011] During filter regeneration, the target ignition timing is retarded to increase the filter temperature. This means that the target ignition timing may become later than the specified time. By prohibiting the shutdown process in this situation, vibrations caused by a failure to compensate for torque fluctuations can be prevented.

[0012] A control device for a hybrid vehicle may be capable of performing a knock determination process that determines whether knock has occurred in an internal combustion engine, and when a period of time during which knock is continuously determined to have occurred in the knock determination process is equal to or longer than a predetermined prescribed period, the control device may regard the target ignition timing as being later than the prescribed time and may prohibit execution of the stop process.

[0013] If knock continues, the target ignition timing is retarded to suppress it. In other words, if knock continues, there's a possibility that the target ignition timing will become later than a specified time. By prohibiting execution of the shutdown process in this situation, the occurrence of vibrations and other issues caused by a failure to compensate for torque variations can be prevented.

[0014] When a transmission device, which is coupled to an internal combustion engine and has a plurality of gears, is switching gears, a control apparatus for a hybrid vehicle may regard the target ignition timing as being later than a prescribed time and may prohibit execution of a stop process.

[0015] While the transmission is switching gears, the target ignition timing is retarded to reduce shift shock caused by the gear shift. In other words, while the transmission is switching gears, there is a possibility that the target ignition timing will become later than the specified time. By prohibiting execution of the stop process in this situation, the occurrence of vibrations and other issues caused by failure to compensate for torque variations can be prevented.

[0016] Regardless of the target ignition timing, the control device for a hybrid vehicle may continue to prohibit the stop process until a predetermined fixed period of time has elapsed after the control device starts prohibiting execution of the stop process.

[0017] The above-described configuration makes it possible to avoid repetition of execution and interruption of the stop process within a short period of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described hereinafter with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0019] Figure 1 is a schematic structural diagram of a vehicle;

[0020] Figure 2is a flowchart showing a processing procedure for ignition timing calculation processing;

[0021] Figure 3 is a flowchart showing a processing procedure of prohibition determination processing;

[0022] FIG4A is a flowchart showing the processing procedure of the first process;

[0023] FIG4B is a flowchart showing the processing procedure of the second process;

[0024] FIG5A is a graph showing an exemplary time variation of torque of an internal combustion engine;

[0025] FIG5B is a graph showing an exemplary time variation of torque of an internal combustion engine; and

[0026] FIG. 5C is a graph showing an exemplary temporal change in torque of the second motor generator. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of a control apparatus for a hybrid vehicle will be described with reference to the accompanying drawings.

[0028] Schematic structure of the vehicle

[0029] like Figure 1 As shown, a hybrid vehicle (hereinafter referred to as vehicle) 500 includes an internal combustion engine 10 , a first motor generator (hereinafter referred to as first MG) 71 , a second motor generator (hereinafter referred to as second MG) 72 , a first inverter 75 , a second inverter 76 , and a battery 77 .

[0030] The internal combustion engine 10, the first MG 71, and the second MG 72 serve as the drive source for the vehicle 500. Details of the internal combustion engine 10 will be described later. The first MG 71 is a motor-generator that functions as both a motor and a generator. The second MG 72 is a motor-generator similar to the first MG 71. The first MG 71 is electrically connected to a battery 77 via a first inverter 75. The second MG 72 is electrically connected to the battery 77 via a second inverter 76. The first inverter 75 and the second inverter 76 convert power between DC and AC. The battery 77 supplies power to the first and second MG 71, 72, and stores the power supplied from the first and second MG 71, 72.

[0031] The vehicle 500 includes a dynamic power distribution integration mechanism 40, a reduction gear 50, a speed reducer 60, a differential gear 61, and drive wheels 62. The crankshaft 14, which is the output shaft of the internal combustion engine 10, and the rotation shaft of the first MG 71 are connected to the dynamic power distribution integration mechanism 40. In addition, the rotation shaft of the second MG 72 is connected to the dynamic power distribution integration mechanism 40 via the reduction gear 50. The dynamic power distribution integration mechanism 40 is connected to the drive wheels 62 via the speed reducer 60 and the differential gear 61.

[0032] The dynamic power distribution integration mechanism 40 is a planetary gear mechanism. It includes a sun gear 41, a ring gear 42, a plurality of pinion gears 43, and a planetary carrier 44. The sun gear 41 is an external gear. It rotates about its own axis. The ring gear 42 is an internal gear. It rotates about the same axis as the sun gear 41. The pinion gears 43 are interposed between the sun gear 41 and the ring gear 42. Each pinion gear 43 meshes with both the sun gear 41 and the ring gear 42. Each pinion gear 43 can revolve around the sun gear 41. More specifically, each pinion gear 43 is supported by the planetary carrier 44 so as to be able to rotate about its own axis and revolve around the sun gear 41. As each pinion gear 43 revolves, the planetary carrier 44 rotates about the same axis as the sun gear 41. The sun gear 41 is coupled to the rotation axis of the first MG 71. The planetary carrier 44 is coupled to the crankshaft 14. The ring gear shaft 45, which is an output shaft of the ring gear 42, is coupled to both the reduction gear 50 and the speed reducer 60. The ring gear shaft 45 corresponds to a drive shaft.

[0033] The reduction gear 50 is a planetary gear mechanism. The reduction gear 50 includes a sun gear 51, a ring gear 52, and a plurality of pinion gears 43. The sun gear 51 is an external gear. The sun gear 51 rotates about its own axis. The ring gear 52 is an internal gear. The ring gear 52 rotates about the same axis as the sun gear 51. The pinion gears 53 are interposed between the sun gear 51 and the ring gear 52. Each pinion gear 53 meshes with both the sun gear 51 and the ring gear 52. Each pinion gear 53 is supported so as to be able to rotate about its own axis and not to revolve around the sun gear 51. The sun gear 51 is connected to the rotation axis of the second MG 72. The ring gear 52 is connected to the aforementioned ring gear shaft 45.

[0034] The crankshaft 14 of the internal combustion engine 10 inputs torque to the planetary carrier 44 of the dynamic power distribution integration mechanism 40. The dynamic power distribution integration mechanism 40 distributes the torque to the sun gear 41 side and the ring gear 42 side. The torque distributed to the sun gear 41 side is input to the rotating shaft of the first MG 71. When the rotating shaft of the first MG 71 is rotated by the torque, the first MG 71 can function as a generator.

[0035] When the first MG 71 functions as a generator, the rotating shaft of the first MG 71 inputs torque to the sun gear 41 of the dynamic power distribution integration mechanism 40. In this case, the dynamic power distribution integration mechanism 40 distributes the input torque to the planetary carrier 44 and the ring gear 42. The torque input to the planetary carrier 44 is input to the crankshaft 14. This torque rotates the crankshaft 14. In this way, the first MG 71 can impart torque to the crankshaft 14.

[0036] The torque distributed from the internal combustion engine 10 to the ring gear 42 side or the torque of the first MG 71 is input to the drive wheels 62 via the ring gear shaft 45, the speed reducer 60, and the differential gear 61. At this time, the speed reducer 60 amplifies the input torque and then outputs the torque. The differential gear 61 allows a rotational speed difference to be generated between the right drive wheel and the left drive wheel 62.

[0037] When the vehicle 500 is decelerating, the second MG 72 functions as a generator, thereby generating regenerative braking power corresponding to the amount of power generated by the second MG 72 in the vehicle 500. On the other hand, when the second MG 72 functions as a motor, the torque of the second MG 72 is input to the drive wheels 62 via the reduction gear 50, the ring gear shaft 45, the speed reducer 60, and the differential gear 61.

[0038] Vehicle 500 includes a first rotational angle sensor 86, a second rotational angle sensor 87, an accelerator sensor 83, and a vehicle speed sensor 85. First rotational angle sensor 86 is positioned near the rotational axis of first MG 71. It detects the rotational position Sm1 of the rotational axis of first MG 71. Second rotational angle sensor 87 is positioned near the rotational axis of second MG 72. It detects the rotational position Sm2 of the rotational axis of second MG 72. Acceleration sensor 83 detects the accelerator operation amount ACP, which is the amount of operation of the accelerator pedal in vehicle 500. Vehicle speed sensor 85 is positioned near drive wheels 62. Vehicle speed sensor 85 detects vehicle speed SP, which is the traveling speed of vehicle 500.

[0039] Schematic structure of an internal combustion engine

[0040] like Figure 1 As shown, the internal combustion engine 10 includes an engine block 10A, the aforementioned crankshaft 14 , a crank angle sensor 18 , a coolant temperature sensor 82 , and a knock sensor 89 .

[0041] The engine block 10A includes four cylinders 11. Each cylinder 11 is a space formed in the engine block 10A. Although not shown, each cylinder 11 contains a piston. The piston can reciprocate in each cylinder 11. The piston in each cylinder 11 is connected to a crankshaft 14 via a connecting rod. The crankshaft 14 rotates as the piston in each cylinder 11 reciprocates. A crank angle sensor 18 is positioned near the crankshaft 14. The crank angle sensor 18 detects the rotational position Scr of the crankshaft 14.

[0042] The engine body 10A includes a water jacket 19. The water jacket 19 is a passage through which coolant flows. The water jacket 19 is positioned around the four cylinders 11. A coolant temperature sensor 82 is positioned at an outlet portion of the water jacket 19. The coolant temperature sensor 82 detects the temperature THW of the coolant.

[0043] Knock sensor 89 is attached to engine body 10A. Knock sensor 89 detects vibration amount VJ of engine body 10A. Internal combustion engine 10 includes four spark plugs 16. Spark plugs 16 are respectively arranged in cylinders 11. The distal end of each spark plug 16 is positioned in the corresponding cylinder 11. Each spark plug 16 ignites the air-fuel mixture of intake air and fuel in each cylinder 11 through spark discharge.

[0044] Internal combustion engine 10 includes an intake passage 15, an air flow meter 81, and four fuel injection valves 17. Intake passage 15 is a passage for introducing intake air into each cylinder 11. Intake passage 15 is connected to each cylinder 11. Air flow meter 81 is positioned at the midpoint of intake passage 15. Air flow meter 81 detects intake air amount GA of intake air flowing through intake passage 15. Four fuel injection valves 17 are positioned in intake passage 15 downstream of air flow meter 81. Four fuel injection valves 17 are respectively provided in cylinders 11. Each of the four fuel injection valves 17 injects fuel into cylinders 11.

[0045] The internal combustion engine 10 includes an exhaust passage 21, a three-way catalyst 22, and a gasoline particulate filter (hereinafter referred to as GPF) 23. The exhaust passage 21 is a passage for discharging exhaust gas from each cylinder 11. The exhaust passage 21 is connected to each cylinder 11. The three-way catalyst 22 is positioned at the midpoint of the exhaust passage 21. The three-way catalyst 22 purifies the exhaust gas. The three-way catalyst 22 has an oxygen storage capacity. The GPF 23 is positioned in the exhaust passage 21 on the downstream side of the three-way catalyst 22. The GPF 23 captures particulate matter (hereinafter referred to as PM) contained in the exhaust gas.

[0046] Schematic structure of the control device

[0047] The vehicle 500 includes a control device 100. The control device 100 can be configured as one or more processors that perform various processes according to a computer program (software). The control device 100 performs at least some of the various processes. The control device 100 can be configured as one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC) or a circuit including a combination of dedicated hardware circuits. The processor includes a CPU and a memory such as a RAM and a ROM. The memory stores program codes or commands that are configured to cause the CPU to perform the processes. The memory is a computer-readable medium and includes all available media that can be accessed by a general-purpose or special-purpose computer. The control device 100 includes a storage device that is an electrically rewritable non-volatile memory.

[0048] The control device 100 receives detection signals from various sensors equipped in the vehicle 500. Specifically, the control device 100 receives detection signals regarding the following parameters.

[0049] Intake air amount GA, which is detected by air flow meter 81;

[0050] The coolant temperature THW, which is detected by the coolant temperature sensor 82;

[0051] The rotational position Scr of the crankshaft 14 , which is detected by the crank angle sensor 18 ;

[0052] Vibration quantity VJ, which is detected by knock sensor 89;

[0053] • The rotational position Sm1 of the rotation shaft of the first MG 71 , which is detected by the first rotation angle sensor 86 ;

[0054] • The rotational position Sm2 of the rotation shaft of the second MG 72 , which is detected by the second rotation angle sensor 87 ;

[0055] The accelerator operation amount ACP, which is detected by the acceleration sensor 83;

[0056] The vehicle speed SP, which is detected by the vehicle speed sensor 85 .

[0057] The control device 100 includes a hybrid control unit 102, an internal combustion engine control unit 104, and a motor control unit 106. The respective functional units will be described in order below.

[0058] Hybrid control unit

[0059] The hybrid control unit 102 controls the vehicle 500 as a whole. Based on the accelerator operation amount ACP and the vehicle speed SP, the hybrid control unit 102 calculates a target value of the engine speed NE, which is the rotational speed of the crankshaft 14 (hereinafter referred to as the target engine speed), and a target value of the engine torque, which is the torque of the internal combustion engine 10 (hereinafter referred to as the target engine torque). Furthermore, based on the accelerator operation amount ACP and the vehicle speed SP, the hybrid control unit 102 calculates a target value of the torque of the first MG 71 (hereinafter referred to as the target first MG torque) and a target value of the torque of the second MG 72 (hereinafter referred to as the target second MG torque).

[0060] Internal combustion engine control unit

[0061] Based on the target engine speed and target engine torque calculated by the hybrid control unit 102, the internal combustion engine control unit 104 controls various components of the internal combustion engine 10. Furthermore, as necessary, the internal combustion engine control unit 104 calculates various parameters indicating the engine's operating state. Specifically, the internal combustion engine control unit 104 calculates the engine speed NE based on the rotational position Scr of the crankshaft 14. Furthermore, the internal combustion engine control unit 104 calculates the engine load based on the engine speed NE and the intake air amount GA. Furthermore, the internal combustion engine control unit 104 calculates the cumulative amount W of PM trapped by the GPF 23 based on the engine load and the coolant temperature THW.

[0062] The internal combustion engine control unit 104 can execute an ignition timing calculation process as a process for controlling the internal combustion engine 10. In the ignition timing calculation process, the internal combustion engine control unit 104 calculates a target ignition timing UG, which is a target value for the ignition timing of the spark plug 16. The internal combustion engine control unit 104 controls the spark plug 16 so that ignition is performed by the spark plug 16 at the target ignition timing UG calculated in the ignition timing calculation process.

[0063] The internal combustion engine control unit 104 can execute a first process for controlling the internal combustion engine 10. As part of the first process, the internal combustion engine control unit 104 can execute a stop process. The stop process is a process for burning particulate matter trapped by the GPF 23 and removing it from the GPF 23. During the stop process, the internal combustion engine control unit 104 stops combustion of the air-fuel mixture in one of the four cylinders 11, that is, stops combustion control for one cylinder 11. Specifically, during the stop process, the internal combustion engine control unit 104 repeats a partial fuel cutoff over multiple consecutive cycles. During the partial fuel cutoff, during one combustion cycle, the internal combustion engine control unit 104 stops combustion of the air-fuel mixture in one of the four cylinders 11 and continues combustion of the air-fuel mixture in the other three cylinders 11. In other words, during the stop process, combustion periods in which the air-fuel mixture is continuously combusted in the three cylinders 11 and non-combustion periods in which the air-fuel mixture is not combusted in the one cylinder 11 are repeated. That is, the "period" herein is not defined by an absolute period of time but by a period equivalent to one cylinder, a period equivalent to two cylinders, etc. Therefore, the time intervals of the combustion period and the non-combustion period vary according to the engine speed NE.

[0064] Internal combustion engine control unit 104 stops fuel injection in one deactivated cylinder (cylinder 11 where combustion of the air-fuel mixture is stopped). Meanwhile, internal combustion engine control unit 104 performs fuel injection in the combustion cylinder (cylinder 11 where combustion of the air-fuel mixture is being performed) so that the air-fuel ratio of the air-fuel mixture in the combustion cylinder becomes richer than the stoichiometric air-fuel ratio. While internal combustion engine control unit 104 is performing the deactivation process, the engine speed (NE) falls below the target engine speed due to the cessation of combustion of the air-fuel mixture in the deactivated cylinder. Furthermore, the engine torque falls below the target engine torque.

[0065] The internal combustion engine control unit 104 can execute a prohibition determination process as a process for controlling the internal combustion engine 10. In the prohibition determination process, when the target ignition timing UG is on the delayed side of the prescribed time UT, that is, when the target ignition timing UG is later than the prescribed time UT, the internal combustion engine control unit 104 prohibits execution of the stop process. The internal combustion engine control unit 104 stores the prescribed time UT in advance. The details of the prescribed time UT will be described later.

[0066] When the stop process described above is executed, the compensation process, described later, is also executed simultaneously with the stop process. Furthermore, when the stop process is executed, the normal process for burning the air-fuel mixture, normally performed by the internal combustion engine control unit 104, is interrupted. Therefore, if the stop process is repeatedly executed and interrupted within a short period of time, the execution and interruption of these processes are repeated, complicating the content of the processing executed by the control device 100. Consequently, the processing load on the control device 100 increases. Furthermore, if the stop process is repeatedly executed and interrupted within a short period of time, the stop process is executed numerous times, even if combustion and removal of PM in the GPF 23 are not progressing, rendering the execution of the stop process futile. In view of this situation, the internal combustion engine control unit 104 continues to prohibit the stop process, regardless of the target ignition timing UG, until a predetermined fixed period C has elapsed after the prohibition of the stop process. This fixed period C is a time interval expected to reduce the processing load on the control device 100 and is pre-set, for example, through experimentation. Furthermore, if the target ignition timing UG becomes retarded by the predetermined time UT at a specific time, there is a high probability that the target ignition timing UG will be likely to remain retarded by the predetermined time UT until a reasonable period of time has passed since the specific time. The specific period of time C is also set in consideration of the expected duration of the target ignition timing UG being likely to remain retarded by the predetermined time UT.

[0067] Motor control unit

[0068] The motor control unit 106 controls the first MG 71 and the second MG 72 based on the target first MG torque and the target second MG torque calculated by the hybrid control unit 102. The motor control unit 106 generally controls the first inverter 75, and thereby controls the first MG 71. In addition, the motor control unit 106 controls the second inverter 76, and thereby controls the second MG 72.

[0069] The motor control unit 106 can execute a second process for controlling the second MG 72. As part of the second process, the motor control unit 106 can execute a compensation process. As described above, when the internal combustion engine control unit 104 executes the stop process, the engine speed NE and engine torque decrease. Therefore, during the compensation process, the motor control unit 106 controls the second MG 72 so that it compensates for the engine torque lost during the non-combustion period during the stop process. In other words, it compensates for the driving power lost due to the cessation of combustion control in one cylinder 11. In this case, the motor control unit 106 calculates a target compensation torque, which is a target value for compensating for the engine torque lost during the non-combustion period. The motor control unit 106 then controls the second MG 72 so that the target compensation torque is output at a time corresponding to the non-combustion period. Assuming that the target ignition timing UG of the spark plug 16 is the MBT ignition timing, the magnitude of the target compensation torque allows for compensation of all engine torque lost during the non-combustion period. The MBT ignition timing is the ignition timing that achieves maximum torque under the current engine operating conditions.

[0070] The prescribed time UT used in the prohibition determination process described above will be described in conjunction with the target compensation torque. As described above, during the compensation process, the reduction in engine torque due to the stop process is compensated by the output of the second MG 72 corresponding to the target compensation torque. The target compensation torque is calculated assuming that the target ignition timing UG is the MBT ignition timing. Therefore, when the target ignition timing UG is on the retarded side of the MBT ignition timing, the reduction in engine torque due to the stop process may not be adequately compensated by the output of the second MG 72 corresponding to the target compensation torque. The prescribed time UT is a limit value on the retarded side within the ignition timing range at which the reduction in engine torque due to the stop process can be adequately compensated by the output of the second MG 72 corresponding to the target compensation torque, and is pre-set, for example, through experimentation. When the engine torque decreases due to the stop process, the resulting torque shock acts on the ring gear shaft 45. In the case where the reduction in engine torque can be appropriately compensated by the output of the second MG 72 corresponding to the target compensation torque, the torque shock acting on the ring gear shaft 45 can be reduced, and also the vibration acting on the vehicle 500 can be reduced. That is, the above-mentioned prescribed time UT is set to a value such that the vibration generated in the vehicle 500 can be kept within an acceptable range.

[0071] Specific processing procedures for ignition time calculation

[0072] Specific processing procedures of the respective processes will be described below in the order of the ignition timing calculation process, the prohibition determination process, the first process, and the second process.

[0073] When the ignition switch of the vehicle 500 is in the on state, the internal combustion engine control unit 104 repeatedly executes the ignition timing calculation process. Figure 2 As shown, when the ignition timing calculation process starts, the internal combustion engine control unit 104 executes the process of step S101.

[0074] In step S101, the internal combustion engine control unit 104 calculates a basic ignition timing. Specifically, the internal combustion engine control unit 104 refers to the latest engine speed NE and engine load. The internal combustion engine control unit 104 then calculates the basic ignition timing based on the latest engine speed NE and engine load. In this embodiment, the basic ignition timing is the MBT ignition timing. After executing step S101, the internal combustion engine control unit 104 proceeds to step S102 to calculate the ignition timing.

[0075] In step S102, the internal combustion engine control unit 104 determines whether a delay condition is satisfied. If the delay condition is satisfied, it is necessary to perform a delay correction of the basic ignition timing. The delay condition is a condition in which at least one of a plurality of delay items is satisfied. Specifically, the delay items are the following two items.

[0076] (A) Vehicle 500 is decelerating, and the engine torque is equal to or lower than prescribed torque ZT.

[0077] (B) The delay correction amount used to resolve knocking is not zero.

[0078] Regarding the above (A), in the case where the engine torque has been reduced to a certain extent while the vehicle 500 is decelerating, it is preferable to transition the internal combustion engine 10 to a state in which the internal combustion engine 10 has a minimum engine speed NE (at which the internal combustion engine 10 can continue to drive independently), that is, an idle state. In order to achieve the transition to the idle state, it is necessary to delay the ignition time. For this purpose, the above (A) is set. The above-mentioned prescribed torque ZT is a value at which no torque shock can be expected even when the internal combustion engine 10 is transitioned to the idle state under the premise that the vehicle 500 is decelerating, and is pre-set, for example, by experiments. The internal combustion engine control unit 104 determines whether the above (A) is satisfied by referring to the latest values ​​of the parameters required to determine whether the above (A) is satisfied (for example, by referring to the vehicle speed SP and the engine speed NE).

[0079] Regarding the above (B), in the case where knock has occurred in the internal combustion engine 10, it is necessary to delay the ignition timing to suppress the knock. For this purpose, requirement (B) is set. In the case where knock has not occurred in the internal combustion engine 10, the delay correction amount is zero. On the other hand, in the case where knock has occurred in the internal combustion engine 10, the delay correction amount is a positive value. As the knock continues, the delay correction amount gradually increases. The delay correction amount is the absolute value of the value to which the ignition timing changes to the delay side. In this context, the internal combustion engine control unit 104 repeatedly performs a knock determination process to determine whether knock has occurred in the internal combustion engine 10. In the knock determination process, based on the vibration amount VJ detected by the knock sensor 89, the internal combustion engine control unit 104 determines whether knock has occurred in each cylinder 11. The internal combustion engine control unit 104 calculates the delay correction amount based on the determination result of the knock determination process, and determines whether requirement (B) is met based on the delay correction amount.

[0080] In a case where both delay items are not satisfied in step S102, the internal combustion engine control unit 104 determines that the delay condition is not satisfied (step S102: No) In this case, the internal combustion engine control unit 104 causes the ignition timing calculation process to proceed to step S104.

[0081] In step S104, the internal combustion engine control unit 104 calculates the unchanged basic ignition timing as the target ignition timing UG. Thus, the internal combustion engine control unit 104 completes a series of processes in the ignition timing calculation process. Then, the internal combustion engine control unit 104 executes the process of step S101 again.

[0082] On the other hand, in the case where at least one of the two delay items is satisfied in step S102, the internal combustion engine control unit 104 determines that the delay condition is satisfied (step S102: YES) In this case, the internal combustion engine control unit 104 advances the ignition timing calculation process to step S103.

[0083] In step S103, the internal combustion engine control unit 104 performs a delay correction on the basic ignition timing calculated in step S101. The internal combustion engine control unit 104 then calculates the value after the delay correction as the target ignition timing UG. The internal combustion engine control unit 104 sets the delay correction amount, taking into account the delay items determined to be satisfied in step S102 and the current engine operating conditions. Specifically, if delay item (A) is satisfied, the ignition timing is shifted to the retarded side of the MBT ignition timing by an amount preset to allow for reduced torque shock due to the transition to idle. Furthermore, if delay item (B) is satisfied, the ignition timing is shifted to the retarded side of the MBT ignition timing by a delay correction amount to address knock. After calculating the target ignition timing UG, the internal combustion engine control unit 104 temporarily terminates the series of steps in the ignition timing calculation process. The internal combustion engine control unit 104 then re-executes the process of step S101.

[0084] Prohibition on determining specific processing procedures

[0085] When the ignition switch of the vehicle 500 is in the on state, the internal combustion engine control unit 104 repeatedly executes the prohibition determination process. Figure 3 As shown, when the prohibition determination process starts, the internal combustion engine control unit 104 executes the process of step S201.

[0086] In step S201, the internal combustion engine control unit 104 determines whether the target ignition time UG is on the delayed side of the prescribed time UT. Specifically, the internal combustion engine control unit 104 refers to the latest target ignition time UG. The internal combustion engine control unit 104 then compares the target ignition time UG with the prescribed time UT. If the target ignition time UG is the same as the prescribed time UT or is on the advanced side of the prescribed time UT (step S201: No), the internal combustion engine control unit 104 proceeds to the prohibition determination process in step S203.

[0087] In step S203, the internal combustion engine control unit 104 turns off the prohibition flag F indicating prohibition of execution of the stop process. Then, the internal combustion engine control unit 104 temporarily ends a series of processes in the prohibition determination process. Then, the internal combustion engine control unit 104 executes the process of step S201 again.

[0088] On the other hand, in a case where the target ignition timing UG is on the retard side of the prescribed time UT in step S201 (step S201 : YES), the internal combustion engine control unit 104 proceeds with the prohibition determination process to step S202 .

[0089] In step S202, the internal combustion engine control unit 104 turns on the prohibition flag F. The internal combustion engine control unit 104 then proceeds to the prohibition determination process in step S204. In step S204, the internal combustion engine control unit 104 determines whether a fixed period of time C has elapsed since the end of the process in step S202. If the fixed period of time C has not elapsed since the end of the process in step S202 (step S204: No), the internal combustion engine control unit 104 executes the process in step S204 again. The internal combustion engine control unit 104 repeats the process in step S204 until the fixed period of time C has elapsed. If the fixed period of time C has elapsed (step S204: Yes), the internal combustion engine control unit 104 temporarily terminates the series of processes in the prohibition determination process. The internal combustion engine control unit 104 then executes the process in step S201 again. In the process in step S204, the prohibition flag F remains on during the fixed period of time C after it is turned on, regardless of the target ignition timing UG.

[0090] Specific processing procedures for the first process

[0091] The internal combustion engine control unit 104 repeatedly executes the first process while the ignition switch of the vehicle 500 is in the on state. As shown in FIG4A , when the first process starts, the internal combustion engine control unit 104 executes the process of step S301.

[0092] In step S301, the internal combustion engine control unit 104 determines whether the start condition of the stop process is satisfied. The start condition is a condition that all of a plurality of start items are satisfied. The start items include the following.

[0093] (A1) The accumulated amount W of PM in the GPF 23 is equal to or greater than the first prescribed amount W1.

[0094] (A2) The prohibition sign F is in the off state.

[0095] (A3) The state in which the target engine speed can be regarded as being substantially constant continues for the first set period H1 or longer.

[0096] (A4) The vehicle speed SP is higher than zero.

[0097] The first prescribed amount W1 is a value that makes the accumulated amount W of PM in the GPF 23 large enough and it is desired to remove PW from the GPF 23, and is set in advance by, for example, an experiment. When the target engine speed changes suddenly, for example, when acceleration is requested, it is not preferable to stop the combustion of the air-fuel mixture by performing the stop process. From this point of view, the above (A3) is set as the starting item. The first set period H1 is a value that makes the state in which the target engine speed is stable be considered to be continuing, and is set in advance by, for example, an experiment. In addition, during the stop of the vehicle 500, it is preferable to stop the operation of the internal combustion engine 10 so that the fuel consumption becomes "0". From this point of view, the above (A4) is set as the starting item.

[0098] In the process of step S301, the internal combustion engine control unit 104 refers to the latest information and past history regarding the parameters required to determine whether the start conditions are met, as exemplified by the accumulated amount W of PM, the prohibition flag F, the target engine speed, and the vehicle speed SP. The internal combustion engine control unit 104 then determines whether the start conditions are met based on this information.

[0099] If at least one of the start conditions is not satisfied in step S301, the internal combustion engine control unit 104 determines that the start condition is not satisfied (step S301: No). In this case, the internal combustion engine control unit 104 temporarily ends the series of processes in the first process. Then, the internal combustion engine control unit 104 executes the process of step S301 again.

[0100] On the other hand, in the case where all the start items are satisfied in step S301, the internal combustion engine control unit 104 determines that the start condition is satisfied (step S301: YES) In this case, the internal combustion engine control unit 104 advances the first process to step S302.

[0101] In step S302, the internal combustion engine control unit 104 cancels the aforementioned normal processing related to combustion of the air-fuel mixture and initiates a stop process. As described above, during the stop process, the internal combustion engine control unit 104 stops fuel injection in the deactivated cylinders and performs fuel injection in the burning cylinders, making the air-fuel ratio of the air-fuel mixture richer than the stoichiometric ratio. Due to the stop process, oxygen is discharged from the deactivated cylinders into the exhaust passage 21. Meanwhile, unburned fuel is discharged from the burning cylinders into the exhaust passage 21. When the oxygen and unburned fuel discharged into the exhaust passage 21 reach the three-way catalyst 22, the unburned fuel is burned there, causing the exhaust temperature to rise. Then, when the high-temperature exhaust gas reaches the GPF 23, the temperature of the GPF 23 rises. When the oxygen discharged from the deactivated cylinders into the exhaust passage 21 reaches the GPF 23, PM trapped in the GPF 23 is burned and removed. After the start of the stop process in step S302, the internal combustion engine control unit 104 proceeds with the first process to step S303.

[0102] In step S303, the internal combustion engine control unit 104 determines whether the end condition of the stop process is satisfied. The end condition is a condition that at least one of a plurality of end items is satisfied. The end items include the following.

[0103] (B1) The accumulated amount W of PM in the GPF 23 is equal to or smaller than the second prescribed amount W2.

[0104] (B2) The time elapsed from the start of the stop process is equal to or longer than the second set period H2.

[0105] (B3) The prohibition sign F is on.

[0106] (B4) The target engine speed has changed suddenly.

[0107] (B5) The vehicle speed SP is zero.

[0108] The second prescribed amount W2 is a value that makes the accumulated amount W of PM in the GPF 23 sufficiently small and allows the stop process to be terminated, and is pre-set, for example, through experiments. The second set period H2 is a value slightly shorter than the maximum acceptable duration of the stop process, taking into account the balance with other controls, and is pre-set, for example, through experiments. Here, (B4) and (B5) are set from the same perspective as (A3) and (A4) described above. In the processing of step S303, similar to the processing of step S301, the internal combustion engine control unit 104 refers to the latest information and past history regarding the parameters required to determine whether the termination criteria have been met. Based on this information, the internal combustion engine control unit 104 then determines whether the termination criteria have been met.

[0109] If none of the end items are satisfied in step S303, the internal combustion engine control unit 104 determines that the end condition is not satisfied (step S303: No). In this case, the internal combustion engine control unit 104 performs the process of step S303 again. The internal combustion engine control unit 104 repeats the process of step S303 until at least one of the end items is satisfied. Then, if at least one of the end items is satisfied, the internal combustion engine control unit 104 determines that the end condition is satisfied (step S303: Yes). In this case, the internal combustion engine control unit 104 proceeds to step S304 in the first process.

[0110] In step S304, the internal combustion engine control unit 104 ends the stop process. Then, the internal combustion engine control unit 104 restarts the normal process. After executing the process of step S304, the internal combustion engine control unit 104 temporarily ends a series of processes in the first process and executes the process of step S301 again.

[0111] Specific procedures for the second process

[0112] The motor control unit 106 repeatedly executes the second process while the ignition switch of the vehicle 500 is in the on state. As shown in FIG4B , when the second process starts, the motor control unit 106 executes the process of step S401.

[0113] In step S401, the motor control unit 106 determines whether the internal combustion engine control unit 104 has started the stop process. If the internal combustion engine control unit 104 has not started the stop process (step S401: No), the motor control unit 106 temporarily ends a series of processes in the second process and executes the process of step S401 again.

[0114] On the other hand, in a case where the internal combustion engine control unit 104 has already started the stop process in step S401 (step S401 : YES), the motor control unit 106 causes the second process to proceed to step S402 .

[0115] In step S402, the motor control unit 106 begins the compensation process. As described above, in the compensation process, the motor control unit 106 calculates the target compensation torque and controls the second MG 72 so that the target compensation torque is output at a time corresponding to the non-combustion period. For example, the motor control unit 106 calculates the target compensation torque by referring to a compensation torque map. In the compensation torque map, for each engine speed NE, the target compensation torque required when the target ignition timing UG is the MBT ignition timing is set as a variable relative to the rotational position Scr of the crankshaft 14. The motor control unit 106 calculates the engine speed NE based on the rotational position Scr of the crankshaft 14 and calculates the compensation target torque corresponding to the engine speed NE according to the compensation torque map. In this way, the motor control unit 106 can calculate the target compensation torque. After the compensation process in the process of step S402 is started, the motor control unit 106 advances the second process to step S403.

[0116] In step S403, the motor control unit 106 determines whether the internal combustion engine control unit 104 has completed the stop process. If the internal combustion engine control unit 104 has not yet completed the stop process (step S403: No), the motor control unit 106 performs the process of step S403 again. The motor control unit 106 repeats the process of step S403 until the internal combustion engine control unit 104 has completed the stop process. Then, if the internal combustion engine control unit 104 has completed the stop process (step S403: Yes), the motor control unit 106 proceeds to the second process of step S404.

[0117] In step S404, the motor control unit 106 ends the compensation process. Then, the motor control unit 106 temporarily ends a series of processes in the second process and executes the process of step S401 again.

[0118] Operation of the embodiment

[0119] Assume that combustion of the air-fuel mixture is being performed in cylinder 11 with the target ignition timing UG being the MTB ignition timing. As shown in FIG5A , when combustion of the air-fuel mixture is performed sequentially in all cylinders 11, the engine torque repeatedly increases at the time of the combustion stroke of cylinder 11. In other words, the engine torque varies periodically depending on the rotational position Scr of crankshaft 14. On the other hand, when the stop process is performed, as shown by the solid line in FIG5B , the engine torque decreases significantly at time t2, at which point the combustion stroke would have been performed if the stop process had not been performed. As shown in FIG5C , during the compensation process, when the stop process is performed, the second gas motor 72 outputs torque at the time when the engine torque reaches its minimum value corresponding to the stopped cylinder. The dashed line in FIG5B indicates the engine torque when combustion of the air-fuel mixture is performed sequentially in all cylinders 11.

[0120] Assume that while the stop process is in progress, the target ignition timing UG is suddenly changed to the delayed side of the MTB ignition timing. Furthermore, assume that the target ignition timing UG is changed to the delayed side of the prescribed time UT. In this case, as indicated by the two-dot chain line in FIG. 5B , the engine torque decreases at time t1 during the combustion stroke of the combustion cylinder. Consequently, the overall phase of the fluctuating engine torque suddenly changes. Consequently, the amount of engine torque reduction at time t2 during the combustion stroke of the stopped cylinder, as well as the timing of the engine torque minimum, shifts compared to when the target ignition timing UG is the MTB ignition timing.

[0121] During the compensation process, the torque output from second MG 72 is based on the target ignition timing UG, which is a prerequisite for the MTB ignition timing. Therefore, when this torque is output when the target ignition timing UG is delayed by the specified time UT, a phase gap exists relative to the timing of engine torque reduction, preventing the reduction in engine torque from being properly offset. Depending on the amount of the phase gap in the engine torque, the torque from second MG 72 is added to the engine torque during the compensation process, generating a new phase peak or increasing the phase peak.

[0122] Therefore, in the prohibition determination process, if the target ignition timing UG is on the delayed side of the prescribed time UT, the prohibition flag F for the stop process is turned on, and execution of the stop process is prohibited. Therefore, if the target ignition timing UG is on the delayed side of the prescribed time UT, the stop process is not executed.

[0123] Effects of the embodiment

[0124] (1) As a process for handling a sudden change in the target ignition timing UG during the execution of the stop process, the motor control unit 106 can obtain information indicating the sudden change in the target ignition timing UG, and the motor control unit 106 can calculate a target compensation torque commensurate with the target ignition timing UG after the change. However, when the motor control unit 106 obtains information indicating the change in the target ignition timing UG, it takes a correspondingly long time to exchange information between the internal combustion engine control unit 104 and the motor control unit 106. Furthermore, after the motor control unit 106 obtains information indicating the change in the target ignition timing UG, the process for the motor control unit 106 to calculate the target compensation torque taking into account the change in the target ignition timing UG also takes a correspondingly long time. Therefore, it is difficult to quickly calculate the target compensation torque corresponding to the target ignition timing UG after the change in the target ignition timing UG before the combustion stroke of the cylinder is stopped, and it is difficult to output the torque corresponding to the target ignition timing UG after the change from the second MG at the time of stopping the combustion stroke of the cylinder. Furthermore, in the case where the target ignition timing UG is changed reasonably significantly to the retard side, the waveform of the phase of the engine torque is an irregular waveform, and therefore, even if the communication speed and the processing speed are increased to cope with the above-mentioned problem, it is difficult to control the second MG 72 so that the second MG 72 outputs a torque having a phase opposite to the reduction in the engine torque caused by the stop processing.

[0125] In this embodiment, if the target ignition timing UG changes significantly to the retarded side, the stop process is not executed. In other words, if there is a risk that the stop process will fail to compensate for changes in engine torque, the stop process is not executed. This prevents the occurrence of vibrations and the like due to a failure to compensate for torque changes during the stop process.

[0126] (2) In this embodiment, the prohibition of the stop process continues until a fixed period C has elapsed after the prohibition of the execution of the stop process. Therefore, it is possible to prevent the execution and interruption of the stop process from being repeated within a short period of time. Therefore, it is possible to prevent the driving of the internal combustion engine 10 from becoming unstable due to the repetition of the execution and interruption of the stop process. Furthermore, it is possible to reduce the processing load on the control device 100.

[0127] variants

[0128] This embodiment can be implemented while being modified as described below. As long as there is no technical inconsistency, the embodiment and modifications described below can be implemented while being combined with each other.

[0129] In addition to turning on the prohibition flag F when the target ignition time UG is actually on the retarded side of the prescribed time UT, or in lieu of turning on the prohibition flag F, turning on the prohibition flag F is permitted when there is a possibility that the target ignition time UG will become retarded from the prescribed time UT. This situation can occur, for example, when a delay condition is satisfied. For example, when delay condition (A) is satisfied, the target ignition time UG can be considered to be on the retarded side of the prescribed time UT, and the prohibition flag F can be turned on. Furthermore, when delay condition (B) is satisfied and it is determined that knock has been occurring for a period equal to or longer than a predetermined prescribed period ZH, the target ignition time UG can be considered to be on the retarded side of the prescribed time UT, and the prohibition flag F can be turned on. As described above, the longer the continuous period during which knock has occurred, the greater the delay correction amount. Therefore, the longer the continuous period during which knock has occurred, the greater the possibility that the target ignition time UG will become retarded from the prescribed time UT. In this example, the occurrence of vibrations, etc., caused by a failure to compensate for torque variations caused by the stop process can be prevented in advance.

[0130] -The content and number of delay items are not limited to the examples in the above embodiment. In addition to the delay items shown in the above embodiment or in place of these delay items, other items can be set. In addition, the number of delay items can be one.

[0131] When the target ignition timing UG is delayed, the temperature of the GPF 23 can be increased. Therefore, a configuration is permitted in which the internal combustion engine control unit 104 can utilize the delay in the target ignition timing UG to execute a filter regeneration process that burns and removes PM trapped in the GPF 23. Furthermore, a request to execute the filter regeneration process can be used as a delay condition. In a configuration in which the internal combustion engine control unit 104 can execute the filter regeneration process, for example, the following conditions can be set as execution conditions for the filter regeneration process. The first condition is that the accumulated amount W of PM in the GPF 23 is equal to or greater than a prescribed accumulated amount ZW. The prescribed accumulated amount ZW can be preset to a value desired for PM removal. The prescribed accumulated amount ZW can be the same as or different from the first prescribed amount W1. The second condition is that the intake air amount GA is equal to or greater than a prescribed intake air amount required for PM combustion removal. The third condition is that the vehicle speed SP is above zero. In other words, execution of the filter regeneration process is avoided while the vehicle 500 is stopped. When all conditions are met, it is determined that the execution conditions are met, and the filter regeneration process can be executed.

[0132] In the case of a configuration in which the internal combustion engine control unit 104 can execute the filter regeneration process as described in the above modification, the execution conditions of the filter regeneration process are not limited to the above conditions. The execution conditions only need to include the first item.

[0133] In a configuration where the internal combustion engine control unit 104 can execute filter regeneration processing as described in the above-described variation, the target ignition timing UG is delayed due to the execution of the filter regeneration process. Consequently, there is a possibility that the target ignition timing UG will become retarded from the prescribed time UT. Therefore, in addition to or in lieu of turning on the prohibition flag F when the target ignition timing UG is actually retarded from the prescribed time UT, it is permitted to treat the target ignition timing UG as being retarded from the prescribed time UT and to turn on the prohibition flag F while the filter regeneration process is being executed. In this example, the occurrence of vibrations, etc., caused by a failure to compensate for torque variations due to the stop process can be prevented in advance.

[0134] The overall configuration of the vehicle 500 is not limited to the example in the above embodiment. For example, a transmission device having a plurality of gears may be used instead of the speed reducer 60.

[0135] In the case where vehicle 500 is equipped with a transmission having multiple gears as described in the above-described modification, it is preferable to retard the target ignition timing UG when the gears of the transmission are being switched to reduce the shift shock caused by the gear switching. Therefore, the requirement that the transmission is switching gears is used as the delay item.

[0136] In the case of vehicle 500 equipped with a transmission as described in the above-described variation, the target ignition timing UG is retarded while the transmission is switching gears. Therefore, there is a possibility that the target ignition timing UG will become retarded from the prescribed time UT. Therefore, in addition to or in lieu of turning on prohibition flag F when the target ignition timing UG is actually retarded from the prescribed time UT, it is permitted to treat the target ignition timing UG as being retarded from the prescribed time UT and to turn on prohibition flag F while the transmission is switching gears. In this example, the occurrence of vibrations, etc., caused by a failure to compensate for torque variations caused by the stop process can be prevented in advance.

[0137] The details of the stop process are not limited to the examples in the above-described embodiment. During the execution of the stop process, the number of deactivated cylinders may increase or decrease. The stop process only requires repeating a combustion period during which combustion of the air-fuel mixture is performed in cylinder 11 and a non-combustion period during which combustion of the air-fuel mixture is not performed in cylinder 11. In other words, the stop process only requires stopping combustion control of some of the four cylinders 11.

[0138] In the above embodiment, the stop process is performed to burn and remove PM from the GPF 23. However, the purpose of the stop process is not limited thereto. The content of the stop process may be changed as appropriate depending on the purpose of the stop process.

[0139] - The contents of the start condition and the end condition in the first process are not limited to the examples in the above-mentioned embodiment. Depending on the contents and purpose of the stop process, appropriate contents can be set as the start condition and the end condition.

[0140] -The basic ignition timing is not limited to the MGT ignition timing. Where appropriate, the basic ignition timing can be corrected using the MGT ignition timing as a standard according to the engine operating state. The basic ignition timing only needs to be an appropriate ignition timing according to the engine operating state.

[0141] The magnitude of the target compensation torque is not limited to the examples in the above-described embodiments. The target compensation torque only needs to have a magnitude that allows compensation for at least a portion of the engine torque lost due to the stopping process.

[0142] The method for setting the target compensation torque is not limited to the example in the above embodiment. The ignition timing used as the standard for setting the target compensation torque may be different from the MGT ignition timing. The ignition timing used as the standard for setting the target compensation torque may vary depending on the engine operating state, rather than being set to a constant timing regardless of the engine operating state. The method for setting the target compensation torque is not critical, as long as the target compensation torque can be set to a torque that can compensate for some amount of engine torque lost due to the shutdown process.

[0143] The prescribed time UT is not limited to the example in the above embodiment. The prescribed time UT only needs to be set in consideration of the ignition timing as a standard for setting the target compensation torque. The prescribed time UT only needs to be a period during which the vibration of the vehicle 500 can be kept within an acceptable range.

[0144] -When the state of the target ignition timing UG on the retard side of the prescribed time UT continues for a reasonable period, the prohibition flag F may be turned on. In this case, when the target ignition timing UG momentarily changes to the retard side of the prescribed time UT for some reason, the stop process is not prohibited.

[0145] After the inhibition of execution of the stop process is started, it is not always necessary to continue the inhibition of the stop process until the fixed period C has elapsed.

[0146] The engine torque lost due to the stopping process can be output from the first MG 71 instead of the second MG 72. The torque of the first MG 71 can be provided to the crankshaft 14. In this way, the engine torque lost due to the stopping process can be compensated.

[0147] The vehicle only needs to have an internal combustion engine and a motor generator as the driving sources, and both the internal combustion engine and the motor generator are connected to the drive shaft. For example, only a single motor generator can be used. In such a vehicle, the motor generator can be controlled to compensate for engine torque lost during stopping. The drive shaft is not limited to the ring gear shaft 45 and only needs to transmit the driving power of the internal combustion engine and the motor generator to the drive wheels.

[0148] The configuration of the internal combustion engine 10 is not limited to the example in the above embodiment. The number of cylinders 11 may be different from that in the above embodiment. The internal combustion engine 10 only needs to include a plurality of cylinders 11 and a spark plug 16 for each cylinder 11.

[0149] The following describes technical ideas derived from the above-described embodiments and modifications.

[0150] -A control device for a hybrid vehicle, the hybrid vehicle including an internal combustion engine and an electric generator as drive sources, the internal combustion engine including a plurality of cylinders and a spark plug for each cylinder, the internal combustion engine and the electric generator being connected to a drive shaft, the control device being capable of performing: an ignition timing calculation process of calculating a target ignition timing of the spark plug; a stop process of stopping combustion control of some of the cylinders; and a compensation process of controlling the electric generator during the stop process so that the electric generator compensates for drive power lost due to stopping of the combustion control, the control device prohibiting execution of the stop process when the torque of the internal combustion engine during deceleration of the hybrid vehicle is equal to or lower than a predetermined prescribed torque.

[0151] - A control device for a hybrid vehicle, the hybrid vehicle including an internal combustion engine and an electric generator as drive sources, the internal combustion engine including a plurality of cylinders, a spark plug for each cylinder, and a filter for capturing particulate matter in exhaust gas, the internal combustion engine and the electric generator being connected to a drive shaft, the control device being capable of performing: an ignition timing calculation process of calculating a target ignition timing of the spark plug; a stop process of stopping combustion control of some of the cylinders; a compensation process of controlling the electric generator during the stop process so that the electric generator compensates for driving power lost due to the stop of combustion control; and a filter regeneration process of removing particulate matter captured in the filter when conditions are satisfied including a condition that the accumulated amount of particulate matter in the filter is equal to or greater than a predetermined prescribed accumulated amount, the control device prohibiting execution of the stop process during execution of the filter regeneration process.

[0152] - A control device for a hybrid vehicle, the hybrid vehicle including an internal combustion engine and an electric generator as drive sources, the internal combustion engine including a plurality of cylinders and a spark plug for each of the plurality of cylinders, the internal combustion engine and the electric generator being connected to a drive shaft, the control device being capable of performing: an ignition timing calculation process of calculating a target ignition timing of the spark plug; a stop process of stopping combustion control of some of the cylinders; a compensation process of controlling the electric generator during the stop process so that the electric generator compensates for driving power lost due to stopping of combustion control; and a knock determination process of determining whether knock has occurred in the internal combustion engine, the control device prohibiting execution of the stop process when it is continuously determined in the knock determination process that the period for which knock has occurred is equal to or longer than a predetermined prescribed period.

[0153] -A control device for a hybrid vehicle, the hybrid vehicle including an internal combustion engine and an electric generator as drive sources, the internal combustion engine including a plurality of cylinders and a spark plug for each cylinder, the internal combustion engine and the electric generator being connected to a drive shaft, a speed change device being connected to the internal combustion engine and having a plurality of gears, the control device being capable of performing: an ignition timing calculation process of calculating a target ignition timing of the spark plug; a stop process of stopping combustion control of some of the cylinders; and a compensation process of controlling the electric generator during the stop process so that the electric generator compensates for the driving power lost due to the stopping of the combustion control, the control device prohibiting the execution of the stop process when the speed change device is switching gears.

Claims

1. A control device for a hybrid vehicle, The hybrid vehicle includes an internal combustion engine and a motor generator as drive sources, the internal combustion engine including a plurality of cylinders and a spark plug for each of the cylinders, the internal combustion engine and the motor generator being coupled to a drive shaft, The control device is capable of performing: Ignition timing calculation processing: calculating the target ignition timing of the spark plug; Stop processing: stopping combustion control of some of the cylinders; and a compensation process in which, during the stop process, the motor generator is controlled so that the motor generator compensates for driving power lost due to the stop of the combustion control, and when the target ignition timing calculated in the ignition timing calculation process is later than a predetermined prescribed time, the control device prohibits execution of the stop process. in, The control apparatus is capable of executing a knock determination process that determines whether knock has occurred in the internal combustion engine; and When a period for which knocking is continuously determined to have occurred in the knock determination process is equal to or longer than a predetermined prescribed period, the control apparatus regards the target ignition timing as being later than the prescribed time and prohibits execution of the stop process.

2. The control device for a hybrid vehicle according to claim 1, wherein When the torque of the internal combustion engine is equal to or lower than a predetermined prescribed torque during deceleration of the hybrid vehicle, the control device regards the target ignition timing as being later than the prescribed time and prohibits execution of the stop process.

3. The control device for a hybrid vehicle according to claim 1, wherein: The internal combustion engine includes a filter that captures particulate matter in the exhaust gas; the control device being capable of executing a filter regeneration process that removes particulate matter trapped in the filter when conditions including a condition that an accumulated amount of particulate matter in the filter is equal to or greater than a predetermined prescribed accumulated amount are satisfied; and During execution of the filter regeneration process, the control device regards the target ignition timing as being later than the prescribed time and prohibits execution of the stop process.

4. The control device for a hybrid vehicle according to claim 1, wherein The control device regards the target ignition timing as being later than the prescribed time and prohibits execution of the stop process when a speed transmission device is switching speeds, the speed transmission device being coupled to the internal combustion engine and having a plurality of speeds.

5. The control device for a hybrid vehicle according to any one of claims 1 to 4, wherein Regardless of the target ignition timing, the control device continues to prohibit the stop process until a predetermined fixed period of time has elapsed after the control device starts prohibiting execution of the stop process.

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