Hybrid vehicle control device

Abstract

To suppress unreasonable variation of rotation speeds of an engine when executing learning processing for confirming a relation between an aperture and an intake flow rate of a throttle valve of an internal combustion engine.SOLUTION: A control device, which controls an internal combustion engine mounted on a vehicle and a rotary electric machine mechanically connected to the internal combustion engine, can make the internal combustion engine drive the rotary electric machine and actuate the rotary electric machine as a power generator to generate electric power, and when a predetermined condition is satisfied, executes learning concerning an aperture of a throttle valve on an intake passage leading to a cylinder of the internal combustion engine, which is configured to command a rotation speed of the rotary electric machine which should be attained, in a transition period during which the condition is satisfied and then the learning is actually started, to execute transfer control by which engine torque outputted by the internal combustion engine is reduced to predetermined magnitude and subsequently start the learning, to converge the rotation speed of the internal combustion engine into a rotation speed lower than a rotation speed during the transfer control and to memorize a learning value in accordance with the aperture of the throttle valve in a state where the rotation speed of the internal combustion engine is converged into the rotation speed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention provides hybrid The present invention relates to control of an internal combustion engine mounted on a vehicle and a rotating electrical machine mechanically connected thereto. [Background technology]

[0002] Recently, hybrid vehicles equipped with two types of power sources, an internal combustion engine and a rotating electric motor (electric motor), have become popular to a certain extent. 1 In a conventional electric vehicle (see the related art), an internal combustion engine drives a motor-generator, which is a rotating electric machine, to generate electricity, and the generated electricity is stored in an electricity storage device, i.e., a battery such as a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and / or a capacitor, and is then supplied to a traction motor-generator, which is also a rotating electric machine.The traction motor-generator then rotates the drive wheels of the vehicle, allowing it to travel.

[0003] Not only the power-generating motor generator but also the traction motor generator can generate electricity through regenerative braking and store the generated electricity in a power storage device. If the power storage device is already full of charge, the power obtained through regenerative braking can be supplied to the power-generating motor generator, which can be operated as an electric motor to rotate and drive the internal combustion engine, thereby consuming surplus electricity.

[0004] In a series hybrid vehicle, the power-generating motor generator also plays a role in motoring (cranking) the internal combustion engine in preparation for starting it up after it has stopped, that is, by rotating the crankshaft, which is the rotating shaft of the internal combustion engine. At this time, the power-generating motor generator receives a supply of electric power from the power storage device.

[0005] In a hybrid vehicle, the internal combustion engine can run without firing by burning fuel in the cylinders, because the traction motor generator consumes the electric charge stored in the power storage device to output rotational driving force. Therefore, even when the vehicle is in operation, the internal combustion engine may remain stopped.

[0006] When the amount of charge stored in the power storage device decreases or when the required output from the traction motor generator is large, the internal combustion engine is started, fuel is supplied to its cylinders and burned, and the power generating motor generator is driven by the rotational driving force output by the internal combustion engine, generating electricity to charge the power storage device or to increase the power supplied to the traction motor generator. Incidentally, in conventional (non-hybrid) vehicles, it is known that after warming up of the internal combustion engine and the three-way catalyst is completed, learning control of the opening of the electronic throttle valve corresponding to the target idle speed is performed. Specifically, when it is confirmed that the actual engine speed has converged to the target idle speed (when a state in which the deviation between the actual engine speed and the target idle speed is within a predetermined error range is maintained for a predetermined time), the opening of the electronic throttle valve at that time is stored as a learned value in a predetermined area of ​​memory (see, for example, Patent Document 2 listed below). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-156134 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-086708 Summary of the Invention [Problem to be solved by the invention]

[0008] An electronic throttle valve is installed in the intake passage of an internal combustion engine as an intake throttle valve. The electronic throttle valve uses a motor to drive the valve element of a butterfly valve that opens and closes the intake flow path, thereby increasing or decreasing the opening angle and thereby increasing or decreasing the flow rate of intake air flowing into the cylinders.

[0009] Over time, deposits build up on the throttle valve disc and the inner periphery of the throttle body that surrounds it. This has a significant impact on the intake air flow, particularly when the throttle valve is narrowed. Furthermore, individual differences in the throttle valve itself and the environmental conditions of the vehicle's location (the amount of oxygen supplied changes depending on the outside temperature and atmospheric pressure) cannot be ignored.

[0010] Therefore, a learning process is performed at appropriate times to confirm the relationship between the throttle valve opening and the intake air flow rate. In this learning process, a certain target engine speed is set, the throttle valve is opened and closed to adjust the intake air flow rate, and the command value for the throttle valve opening when the actual engine speed converges to the target engine speed is stored in memory as a learned value.

[0011] In conventional (non-hybrid) vehicles that run solely by inputting engine torque output from the internal combustion engine to the drive wheels, learning of the throttle valve opening can be accomplished while the internal combustion engine is idling when the vehicle is stopped. However, in hybrid vehicles, there are few opportunities to idle the internal combustion engine in the first place. In addition, in hybrid vehicles, a high-output rotating electric machine is connected to the internal combustion engine via a gear mechanism. Therefore, if the throttle valve opening learning method used in conventional vehicles is applied as is, the following problems may arise: (i) If learning is simply started in the same way as before when the internal combustion engine is firing and driving the rotating electric machine, the load torque of the rotating electric machine relative to the internal combustion engine may be too large, causing the engine to stall, or conversely, the load torque of the rotating electric machine may be too small, causing the engine to rev up. In particular, if the power supply from the on-board power storage device to the electronic control unit is cut off, the most recent learned values ​​stored in memory are lost. If learning is then performed again, the throttle valve opening will be significantly adjusted, resulting in large fluctuations in engine speed.

[0012] (ii) By performing learning while the rotating electric machine is operating at no load, the engine torque output by the internal combustion engine can be reduced to the same level as during idle operation. However, on the other hand, the gears of the gear mechanism interposed between the internal combustion engine and the rotating electric machine repeatedly strike each other, causing a gear rattle noise that may be transmitted to the vehicle cabin as an abnormal noise or vibration that can be perceived by the vehicle occupants, including the driver. In an internal combustion engine, the piston of each cylinder presses against the crankshaft, generating a driving force to rotate it, only during the expansion stroke of that cylinder. In other words, the instantaneous value of engine torque pulsates up and down. When the average torque is small, the gear teeth on the internal combustion engine side alternate between pressing against the gear teeth on the rotating electric machine side and vice versa. This causes the gear rattle noise. Even in conventional vehicles, a small-output alternator is attached to the internal combustion engine, but the internal combustion engine and alternator are connected via a transmission mechanism with a belt wound around a pulley, so no gear rattle noise is generated.

[0013] The present invention provides Installed in hybrid vehicles The intended purpose of this invention is to suppress undesirable fluctuations in engine speed when a learning process is performed to confirm the relationship between the throttle valve opening of the internal combustion engine and the intake air flow rate, and also to suppress the occurrence of gear rattle noise in the gear mechanism interposed between the internal combustion engine and the rotating electrical machine. [Means for solving the problem]

[0014] In the present invention, hybrid Internal combustion engines mounted on vehicles and alwaysA control device for controlling a mechanically connected rotating electric machine, which can be driven by an internal combustion engine to operate as a generator to generate electricity, and which, when a predetermined condition is met, executes learning regarding the opening of a throttle valve in an intake passage connected to a cylinder of the internal combustion engine, and during the transitional period from when the condition is met to when the learning actually starts, commands the rotation speed of the rotating electric machine to be achieved, and executes transition control to reduce the engine torque output by the internal combustion engine to a required magnitude, and then starts the learning, converging the rotation speed of the internal combustion engine to a speed lower than the rotation speed during the transitional control, and stores a learned value corresponding to the opening of the throttle valve in that state. hybrid A vehicle control device was configured.

[0015] In the present invention, when learning the throttle valve opening, the engine speed is not immediately controlled to the target speed being learned, but rather transition control is performed to gradually change the engine speed, which prevents a sudden change in the throttle valve opening and makes it possible to suppress large fluctuations in the engine speed.

[0016] The internal combustion engine and the rotating electric machine may be mechanically connected via a gear mechanism. In this case, once the engine torque output by the internal combustion engine has been reduced to a required level by the transition control, it is preferable to command the load torque of the rotating electric machine to be achieved while continuing power generation by the rotating electric machine during the learning process. In this way, the load torque applied to the internal combustion engine by the rotating electric machine can be kept constant while learning the throttle valve opening, thereby obtaining an accurate learned value.

[0017] In addition, during the learning, the rotating electrical machine continues to generate electricity. A constant load torque of the rotating electrical machine to be achieved is commanded. The engine torque output by the internal combustion engine is controlled so that the gear teeth on the internal combustion engine side of the gear mechanism always press against the gear teeth on the rotating electrical machine side. The magnitude corresponding to the load torque In this case, the throttle valve is not fully closed but is slightly opened. [Effects of the Invention]

[0018] According to the present invention, Installed in hybrid vehicles This can suppress undesirable fluctuations in engine speed when performing a learning process to confirm the relationship between the throttle valve opening of the internal combustion engine and the intake air flow rate, and can also suppress the occurrence of gear rattle noise in the gear mechanism between the internal combustion engine and the rotating electrical machine. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram showing a schematic configuration of a series hybrid vehicle and a control device according to an embodiment of the present invention; [Figure 2] FIG. 3 is a flowchart showing an example of a procedure of a process executed by the control device according to the embodiment in accordance with a program. [Figure 3] 3A and 3B are diagrams illustrating the contents of control performed by the control device according to the embodiment. [Figure 4] FIG. 3 is a timing chart showing a control process performed by the control device of the embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a schematic configuration of the main systems of a vehicle in this embodiment. The vehicle in this embodiment is a hybrid vehicle equipped with two types of power sources. It includes an internal combustion engine 1, a power generation motor / generator 2 which is a rotating electric machine driven by the internal combustion engine 1 to generate electricity, a power storage device 3 which stores the electric power generated by the power generation motor / generator 2, and a traction motor / generator 4 which is a rotating electric machine which receives electric power from the power generation motor / generator 2 and / or the power storage device 3 to drive drive wheels 62 of the vehicle.

[0021] This hybrid vehicle is a series hybrid electric vehicle that uses the internal combustion engine 1 only for generating electricity, and the driving force for driving is supplied to the drive wheels 62 of the vehicle exclusively from the traction motor generator 4. The internal combustion engine 1 and the drive wheels 62 are mechanically separated, and no rotational driving force is transmitted between them. Therefore, the internal combustion engine 1 can rotate and stop completely independently of the traction motor generator 4 and the drive wheels 62. Therefore, while the ignition switch (power switch or ignition key) is turned ON and the vehicle is ready to run when the driver depresses the accelerator pedal, the internal combustion engine 1 may not operate, which involves burning fuel, if the power storage device 3 has stored a sufficient charge and the brake booster 15 has stored a sufficient negative pressure.

[0022] The crankshaft, which is the rotating shaft of the internal combustion engine 1, is mechanically connected to the rotating shaft of the power-generator motor-generator 2 via a gear mechanism 7 (the two are always connected and never disconnected; there is no clutch or the like between them that can be switched on or off). The power-generator motor-generator 2 generates electricity by inputting the rotational driving force output by the internal combustion engine 1 into the power-generator motor-generator 2. The generated electricity is charged to the power storage device 3 and / or supplied to the traction motor-generator 4. The power-generator motor-generator 2 also functions as a motoring electric motor that generates rotational driving force to rotate the crankshaft of the internal combustion engine 1. For example, the power-generator motor-generator 2 performs cranking in preparation for starting the internal combustion engine 1 that has been stopped.

[0023] The traction motor generator 4 generates driving force for driving the vehicle and inputs the driving force to the drive wheels 62 via the speed reducer 61. The traction motor generator 4 also generates electricity by rotating along with the drive wheels 62, recovering the kinetic energy of the vehicle as electrical energy. The electricity generated by this regenerative braking is charged into the electricity storage device 3.

[0024] However, if the electric charge has already been stored to the full capacity of the power storage device 3 and further charging is difficult, the traction motor generator 4 supplies the regeneratively generated electric power to the power generation motor generator 2, which operates as an electric motor to rotate and drive the internal combustion engine 1. This consumes excess electric power while maintaining the braking performance of the vehicle. Also, since the rotation of the internal combustion engine 1 is maintained at this time, a fuel cut can be performed to temporarily stop the fuel supply to the cylinders of the internal combustion engine 1.

[0025] The generator inverter 21 converts AC power generated by the power generation motor generator 2 into DC power, and then inputs the DC power to the power storage device 3 or the driving machine inverter 41. When the power generation motor generator 2 is operated as an electric motor, the generator inverter 21 also converts DC power supplied from the power storage device 3 and / or the driving machine inverter 41 into AC power and then inputs it to the power generation motor generator 2.

[0026] The drive machine inverter 41 converts DC power supplied from the power storage device 3 and / or the generator inverter 21 into AC power and inputs it to the traction motor generator 4. The drive machine inverter 41 also converts AC power generated by the traction motor generator 4 when regenerative braking of the vehicle is performed into DC power and inputs it to the power storage device 3 or the generator inverter 21. The generator inverter 21 and the drive machine inverter 41 form part of a PCU (Power Control Unit) 02.

[0027] The power storage device 3 is a battery and / or a capacitor, etc. The battery is a high-voltage secondary battery with a high energy density, such as a lithium-ion secondary battery or a nickel-metal hydride secondary battery. The power storage device 3 charges and stores the electric power generated by the power generation motor generator 2 and the traveling motor generator 4. The power storage device 3 also discharges the electric power required to operate the power generation motor generator 2 and the traveling motor generator 4 as electric motors, and supplies the necessary electric power to the motor generators 2 and 4.

[0028] The internal combustion engine 1 mounted on the hybrid vehicle of this embodiment is, for example, a spark-ignition four-stroke reciprocating engine and includes a plurality of cylinders 11 (for example, three cylinders). An injector 111 that injects fuel toward the intake port is provided near the intake port of each cylinder 11. Also, an ignition plug 112 is attached to the ceiling of the combustion chamber of each cylinder 11. The ignition plug 112 receives an induced voltage generated by an ignition coil and causes a spark discharge between a center electrode and a ground electrode.

[0029] In this embodiment, the control device 0 that controls the internal combustion engine 1, the power generation motor generator 2, the power storage device 3, the inverters 21, 41, and the traction motor generator 4 is made up of multiple ECUs, namely, an EFI (Electronic Fuel Injection) ECU 01 that controls the internal combustion engine 1, an MG (Motor Generator) ECU 02 that controls the motor generators 2, 4 and the inverters 21, 41, a BMS (Battery Management System) ECU 03 that controls the power storage device 3, and an HV (Hybrid Vehicle) ECU 00 that is a higher-level controller that oversees these controls, all of which are interconnected so as to be able to communicate with each other via an electric communication line such as a CAN (Controller Area Network). Each of the ECUs 00, 01, 02, and 03 is a microcomputer system having a processor, a memory, an input interface, an output interface, etc.

[0030] The control device 0 receives a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from a crank angle sensor that detects the rotation angle of the crankshaft of the internal combustion engine 1 and the engine speed, an accelerator opening signal c output from a sensor that detects the amount of depression of the accelerator pedal by the driver as an accelerator opening (in other words, the driving force that the driver is requesting from the vehicle (driving motor generator 4 of the vehicle)), an intake air temperature / intake pressure signal d output from a temperature / pressure sensor that detects the intake air temperature and intake pressure in the intake passage 13 (particularly, the surge tank 133 or the intake manifold 134) connected to the cylinder 11 of the internal combustion engine 1, a coolant temperature signal e output from a water temperature sensor that detects the temperature of the coolant of the internal combustion engine 1, a vibration signal f output from a vibration type knock sensor that detects the magnitude of vibration of the cylinder block that contains the cylinder 11 of the internal combustion engine 1, and a battery SOC (State Of Charge) output from a sensor (particularly, a battery current and / or battery voltage sensor) that detects the amount of charge stored in the power storage device 3. A charge signal g, a negative pressure signal h output from a negative pressure sensor that detects the negative pressure stored in the constant pressure chamber of the brake booster 15, etc. are input.

[0031] The control device 0 controls the increase or decrease of the rotational driving force output by the driving motor generator 4, the rotational driving force output by the internal combustion engine 1, and the amount of power generated by the power generation motor generator 2, depending on the amount of depression of the accelerator pedal operated by the driver, the current vehicle speed, the amount of charge stored in the storage device 3, the power generated by the power generation motor generator 2, etc., which are sensed via various sensors.

[0032] In principle, if the power storage device 3 currently stores sufficient charge and the output required of the traction motor generator 4 is small, the supply of fuel to the internal combustion engine 1 is cut off and the internal combustion engine 1 is not operated. Conversely, if the amount of charge stored in the power storage device 3 falls below a lower limit or the output required of the traction motor generator 4 is large, the internal combustion engine 1 is started, fuel is supplied to the cylinders 11 and fired to combust it, and the rotational driving force output by the internal combustion engine 1 drives the generator motor generator 2, generating electricity to charge the power storage device 3 or to increase the power supplied to the traction motor generator 4.

[0033] The output (for driving the vehicle) required by the vehicle driver from the driving motor generator 4 is determined by the amount of depression of the accelerator pedal operated by the driver and the vehicle speed. The driving force to be applied to the drive wheels 62 increases as the accelerator opening increases. The required output increases as the driving force to be applied to the drive wheels 62 increases, and also increases as the vehicle speed increases.

[0034] In the low output range where the driving force to be applied to the drive wheels 62 is relatively small and the vehicle speed is relatively low, the control device 0 stops the firing operation of the internal combustion engine 1 by not supplying fuel to it and does not operate the power-generating motor generator 2 as a generator. In the low output range, the traction motor generator 4 receives power only from the power storage device 3 and outputs driving force for traveling the vehicle. The low output range is typically when the accelerator opening is 0 or below a predetermined value, or when the vehicle is decelerating.

[0035] In the medium to high output range where the driving force to be applied to the drive wheels 62 is greater than a certain level or the vehicle speed is greater than a certain level, the control device 0 supplies fuel to the internal combustion engine 1 to perform firing operation and operates the power-generating motor-generator 2 as a generator. In the medium output range where the required output is not significantly greater, the traction motor-generator 4 receives power mainly from the power-generating motor-generator 2 and outputs driving force for running the vehicle. At this time, the power storage device 3 supplies only a small amount of power or no power at all. In the high output range where the required output is significantly greater, the traction motor-generator 4 receives power from both the power-generating motor-generator 2 and the power storage device 3 and outputs driving force for running the vehicle.

[0036] Basically, the output required of the internal combustion engine 1 during firing operation increases as the output required of the traction motor-generator 4 increases. However, this also depends on the amount of charge currently stored in the electricity storage device 3. When the amount of charge in the electricity storage device 3 becomes insufficient, it is necessary to charge it as quickly as possible, and even if the output required of the traction motor-generator 4 is small, the output required of the internal combustion engine 1 for power generation may increase.

[0037] The EFI ECU01, which is part of the control device 0, acquires various pieces of information b, d, e, and f required for operational control of the internal combustion engine 1 via an input interface, determines the engine speed, and estimates the amount of air to be taken into the cylinder 11. The engine speed can be detected (in the EFI ECU01) via a crank angle sensor attached to the internal combustion engine 1, but can also be detected (in the MG ECU02) via a resolver attached to the power-generating motor generator 2. Then, the EFI ECU01 determines operational parameters of the internal combustion engine 1, such as a required fuel injection amount (necessary to realize a target air-fuel ratio) commensurate with the amount of intake air, fuel injection timing (including the number of fuel injections per combustion), fuel injection pressure, ignition timing (including the number of ignitions per combustion), and required EGR rate (or EGR gas amount). The EFI ECU01 outputs various control signals i, j, k, and l corresponding to the operating parameters to the igniter of the spark plug 112 of each cylinder 11 of the internal combustion engine 1, the injector 111, the electronic throttle valve 132 on the intake passage 13, the EGR valve 123, etc. via the output interface.

[0038] The EFI ECU01, which controls the operation of the internal combustion engine 1, and the HV ECU00, which controls the overall control of the hybrid vehicle including the power-generator motor-generator 2 and the traction motor-generator 4, exist independently of each other. The EFI ECU01 receives information regarding the target output of the internal combustion engine 1 during firing operation, in other words, the target engine speed and / or target engine torque (this may be the target engine speed or target engine torque itself, or values ​​such as the power generated by the power-generator motor-generator 2, the output voltage or current, or the load torque applied to the internal combustion engine 1 by the power-generator motor-generator 2). In accordance with the received information, the EFI ECU01 controls the opening of the throttle valve 132, the amount of fuel injected from the injector 111, the timing of spark ignition of the air-fuel mixture by the spark plug 112, the opening of the EGR valve 123, etc., to achieve the target engine speed and / or target engine torque.

[0039] The PCU (or MG ECU) 02 also receives information regarding the target output of the power generation motor generator 2 operating as a generator to generate electricity, in other words, the target MG rotation speed and / or the target MG load torque (which may be the target MG rotation speed or the target MG load torque itself, or values ​​such as the power generated by the power generation motor generator 2, or the voltage or current output). In accordance with the received information, the PCU 02 controls the generated power, voltage, or current (which may be the duty ratio in PWM (Pulse Width Modulation) control) to achieve the target MG rotation speed and / or the target MG load torque.

[0040] Over time, deposits accumulate on the valve disc of the throttle valve 132 in the intake passage 13 of the internal combustion engine 1 and on the inner periphery of the throttle body surrounding it. This significantly affects the flow rate of intake air through the intake passage 13, particularly when the throttle valve 132 is narrowed. There are also individual differences in the throttle valve 132 itself. Furthermore, the environmental conditions of the vehicle's current location cannot be ignored. This is because the amount of oxygen actually supplied to the cylinder 11 changes depending on the current outside temperature and atmospheric pressure.

[0041] Even in a hybrid vehicle, the opening of the throttle valve 132 may be reduced to fire or motor the internal combustion engine 1. For example, as already mentioned, when the negative pressure stored in the brake booster 15 decreases, the throttle valve 132 is opened to a small degree and the internal combustion engine 1 is rotated at a low intake flow rate in order to supply the intake negative pressure to the brake booster 15. Furthermore, in an extremely low temperature environment, it is necessary to increase the temperature of the power storage device 3 or to keep the power storage device 3 warm, and although the power storage device 3 is not actively charged, the throttle valve 132 may be opened to a small degree and the internal combustion engine 1 may be fired at a low intake flow rate (low engine load factor).

[0042] In order to stabilize the operation of such an internal combustion engine 1, it is necessary to accurately control the flow rate of intake air flowing through the intake passage 13 toward the cylinder 1. Therefore, the control device 0 of this embodiment timely executes a learning process to confirm the relationship between the opening of the throttle valve 132 and the intake flow rate.

[0043] 2, when the internal combustion engine 1 is already in firing operation (step S1) and predetermined learning permission conditions are met (step S2), the control device 0 starts learning about the opening of the throttle valve 132. Step S1 means that the stopped internal combustion engine 1 is not started in order to learn the opening of the throttle valve 132 (to avoid fuel consumption and noise generation).

[0044] In step S2, the learning permission conditions are, for example, that the coolant temperature of the internal combustion engine 1 is higher than a predetermined value, that the amount of electricity stored in the coin storage device 3 is higher than a predetermined value (SOC is higher than a predetermined value), and that the drive output required of the traveling motor generator 4 according to the amount of depression of the accelerator pedal by the driver is small (the vehicle can continue to travel even if the electricity generating motor generator 2 does not generate electricity), etc. However, as will be described later, even while the opening of the throttle valve 132 is being learned, the electricity generating motor generator 2 generates a small amount of electricity and continues to apply a certain load to the internal combustion engine 1.

[0045] In detail, the EFI ECU01 confirms that at least some of the learning permission conditions are met, and then requests the EV ECU00 to permit learning of the opening of the throttle valve 132. Upon receiving this, the EV ECU00 confirms that the remaining conditions are met, and then begins learning the opening of the throttle valve 132.

[0046] After the above steps S1 and S2 are established, during the transitional period until the learning of the opening of the throttle valve 132 actually begins, the control device 0 commands the target rotation speed of the power generation motor generator 2 (or the internal combustion engine 1) to be achieved, and performs transition control to reduce the engine torque output by the internal combustion engine 1 to the required magnitude (step S3).

[0047] Immediately before learning of the opening degree of the throttle valve 132 is started, the internal combustion engine 1 fires to drive the power-generating motor-generator 2, which then functions as a generator to generate electricity. During normal power generation, the EV ECU00 commands the EFI ECU01 to set a target value for the engine torque to be output by the internal combustion engine 1 (this may be the target engine torque itself, or a value suggesting the target engine torque, such as the generated power, output voltage, or output current of the power-generating motor-generator 2, or the load torque on the internal combustion engine 1). The EV ECU00 also commands the PCU02 to set a target value for the rotation speed to be achieved by the power-generating motor-generator 2 (this may be the target MG rotation speed itself, or a value suggesting the target MG rotation speed, such as the generated power, output voltage, or output current of the power-generating motor-generator 2). The EFI ECU01 controls the internal combustion engine 1 to achieve the target engine torque set by the EV ECU00. The current engine torque can be estimated using a known method, but it may also be detected via a torque sensor. In addition, the PCU02 performs feedback control to manipulate the generated power, output voltage, or output current so as to reduce the deviation between the target rotation speed given by the EV ECU00 and the actually measured rotation speed.

[0048] In the transition control step S3 for transitioning from normal control to learning control, the rotational speeds of the internal combustion engine 1 and the connected power-generator motor-generator 2 are first reduced to a rotational speed N' that is slightly higher than the target rotational speed N during learning (for example, approximately 100 rpm higher in engine rotational speed terms). At the same time, the load torque applied to the internal combustion engine 1 by the power-generator motor-generator 2 is reduced to a torque T' that is slightly higher than the target torque T during learning (for example, approximately 1 Nm higher in torque terms acting on the crankshaft of the internal combustion engine 1). To achieve this, the target rotational speed command given from the EV ECU 00 to the PCU 02 is changed to a value equivalent to N' in engine rotational speed terms. This corresponds to the process leading to point α in FIG. 3 and the period from time t0 to time t1 in FIG. 4. During this process, the engine rotational speed and engine torque also decrease to approach point α.

[0049] Once the engine speed reaches N', the load torque applied to the internal combustion engine 1 by the power-generator motor / generator 2 is reduced to the target torque T being learned while maintaining the target engine speed at N'. To achieve this, the EV ECU 00 issues a target engine speed command to the EFI ECU 01 instead of the target engine torque command it previously issued, and this target engine speed is set to N. In response to this command, the EFI ECU 01 performs feedback control to manipulate the throttle valve 132 opening, fuel injection amount, and other parameters to reduce the deviation between the target engine speed N and the actual engine speed. Here, the target engine speed in the PCU 02 is N' in engine speed terms, and the target engine speed in the EFI ECU 01 is N, so that N' > N. The reason for this is to prevent engine speed from revving up during the process of reducing the load torque applied to the internal combustion engine 1 to the target torque T being learned. This process corresponds to the process from point α to point β in FIG. 3 and the period from time t1 to time t2 in FIG. 4. During this process, the engine torque output by the internal combustion engine 1 also drops to approach point β.

[0050] When the rotation speed reaches N' and the load torque reaches T, transition control is complete, and the opening of the throttle valve 132 is finally learned (step S4). In learning step S4, the rotation speed of the internal combustion engine 1 is converged to the target value N being learned while maintaining the load torque at the target torque T being learned. To achieve this, the EV ECU00 issues a target load torque command to the PCU02, instead of the target rotation speed command that was previously issued. In other words, while the PCU02 previously feedback-controlled the power-generator motor-generator 2 so that the rotation speed was maintained at N' when converted to engine rotation speed, from now on it will feedback-control the power-generator motor-generator 2 so that the load torque is maintained at T when converted to torque acting on the crankshaft. The current load torque by the power-generator motor-generator 2 can be estimated using a known method, but it may also be detected via a torque sensor.

[0051] On the other hand, the EFI ECU01 performs feedback control of the internal combustion engine 1 so that the actual engine speed changes from N' to the target speed N and converges thereto. Learning step S4 is the process from point β to point γ in FIG. 3, and is the period after time t2 in FIG.

[0052] Throughout steps S3 and S4, the power-generating motor-generator 2 consistently operates as a generator, is rotationally driven by the internal combustion engine 1, and serves as a mechanical load on the internal combustion engine 1. During learning step S4, the load torque applied to the crankshaft of the internal combustion engine 1, i.e., the magnitude of the engine torque that should be output by the internal combustion engine 1, is maintained at or near a positive constant value T greater than 0. It goes without saying that the target engine speed N is a positive value.

[0053] When the engine speed has converged to the target speed N, the EFI ECU 01, which is an element of the control device 0, stores in memory a learned value corresponding to the opening of the throttle valve 132 at that time. This learned value of opening indicates the opening of the throttle valve 132 (a control signal given to the throttle motor or an output signal from the throttle position sensor) required to control the amount of intake air flowing through the intake passage 13 connected to the cylinder 11 to a certain low flow rate. The learned value may be the opening value of the throttle valve 132 itself when the engine speed has converged to the target speed N, or it may be the amount of deviation from a certain reference opening value (or a correction amount by feedback control of the speed). The learned value acquired in learning step S4 is used for subsequent control of the internal combustion engine 1.

[0054] After the learning of the opening degree of the throttle valve 132 is completed, the normal power generation control may be restored, or the firing operation of the internal combustion engine 1 may be stopped.

[0055] In this embodiment, the control device 0 controls an internal combustion engine 1 mounted on a vehicle and a rotating electric machine (motor generator for generating electricity) 2 mechanically connected to the internal combustion engine 1, and the rotating electric machine 2 can be driven by the internal combustion engine 1 and operated as a generator to generate electricity. When a predetermined condition is met, the control device 0 executes learning regarding the opening of a throttle valve 132 on an intake passage 13 connected to a cylinder 11 of the internal combustion engine 1. During the transitional period from when the condition is met to when the learning actually starts, the control device 0 commands the rotation speed N' of the rotating electric machine 2 (or the internal combustion engine 1) to be achieved, and performs transition control (step S3) to reduce the engine torque output by the internal combustion engine 1 to a required magnitude T, and then starts the learning (step S4). The control device 0 for a vehicle is configured to converge the rotation speed of the internal combustion engine 1 to a rotation speed N lower than the rotation speed N' during the transitional control, and store a learning value corresponding to the opening of the throttle valve 132 in that state.

[0056] The internal combustion engine 1 and the rotating electric machine 2 are mechanically connected via a gear mechanism 7. In the transition control during the transition period, a rotation speed N' that the internal combustion engine 1 should achieve is commanded, and the engine torque output by the internal combustion engine 1 is reduced to a required magnitude T while continuing power generation by the rotating electric machine 2. In the control during learning, the rotation speed of the internal combustion engine 1 is converged to a rotation speed N that is lower than the rotation speed N' during the transition control while continuing power generation by the rotating electric machine 2, and a learned value determined based on the opening of the throttle valve 132 in that state is stored and held.

[0057] In this embodiment, when learning the opening of the throttle valve 132, rather than directly transitioning from normal power generation control to the target torque T and target rotational speed N (point γ in FIG. 3), transition control is performed to temporarily set the rotational speed to N', which is slightly higher than the target rotational speed N, while reducing the torque to T (points α and β in FIG. 3), and then learning control is started to make the torque follow the target torque T and target rotational speed N. This prevents a sudden change in the opening of the throttle valve 132 as learning is performed, making it possible to suppress undesirable fluctuations in the engine rotational speed.

[0058] In addition, during both the transition control and the learning, the rotating electric machine 2 is consistently operated as a generator, continuously applying a certain amount of load to the internal combustion engine 1 that drives it. The internal combustion engine 1 needs to continuously output a certain amount of engine torque to maintain rotation. Therefore, the opening of the throttle valve 132 during the transition control and the learning is made larger than the opening (fully closed or nearly fully closed) of the throttle valve during idling in a conventional (non-hybrid) vehicle. Furthermore, the gear teeth on the internal combustion engine 1 side of the gear mechanism 7 continue to push against the gear teeth on the rotating electric machine 2 side, preventing teeth from clashing between the two gears. The absence of rattle noise contributes to further improvement of the vehicle's noise and vibration (NV) performance.

[0059] It should be noted that the present invention is not limited to the above-described embodiment, and for example, the application of the present invention is not limited to the above-described series hybrid vehicle.

[0060] In addition, the specific configuration of each part and the processing procedure can be modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0061] 0...Control device 00...ECU that controls the rotating electrical machine (HV ECU) 01...ECU that controls the internal combustion engine (EFI ECU) 1...Internal combustion engine 11...cylinder 13...Intake passage 132...Throttle valve 2... Rotating electric machine (motor generator for power generation) 7...Gear mechanism

Claims

1. A control device for controlling an internal combustion engine mounted on a hybrid vehicle and a rotating electric machine that is always mechanically connected to the internal combustion engine, The internal combustion engine drives a rotating electric machine, which can be operated as a generator to generate electricity. Also, when a predetermined condition is met, learning is performed regarding the opening of a throttle valve in an intake passage connected to a cylinder of the internal combustion engine, during a transitional period from when the condition is satisfied until when the learning actually starts, a transition control is performed in which a rotation speed of the rotating electric machine to be achieved is commanded and an engine torque output by the internal combustion engine is reduced to a required magnitude; The control device for a hybrid vehicle then starts the learning, converges the internal combustion engine speed to a speed lower than the speed during the transition control, and stores a learned value corresponding to the throttle valve opening in that state.

2. The internal combustion engine and the rotating electric machine are always mechanically connected via a gear mechanism, 2. A control device for a hybrid vehicle according to claim 1, wherein, if the engine torque output by the internal combustion engine is reduced to a required magnitude by the transition control, the load torque of the rotating electric machine to be achieved is commanded while continuing power generation by the rotating electric machine during the learning.

3. The internal combustion engine and the rotating electric machine are always mechanically connected via a gear mechanism, 3. A control device for a hybrid vehicle as described in claim 1 or 2, wherein during the learning, a constant load torque of the rotating electric machine to be achieved while continuing power generation by the rotating electric machine is commanded, and the engine torque output by the internal combustion engine is set to a magnitude corresponding to the load torque so that the gear teeth on the internal combustion engine side of the gear mechanism always continue to push against the gear teeth on the rotating electric machine side.

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