control device

Abstract

To detect generation of abnormal sound or vibration precisely during firing of an internal combustion engine in a gear mechanism which joins a rotary electric machine to the internal combustion engine.SOLUTION: A control device which controls an internal combustion engine and a rotary electric machine which is connected to the internal combustion engine via a gear mechanism, is configured so as to measure time required for an output axis of the internal combustion engine to rotate by unit angle repeatedly during execution of firing which rotates the rotary electric machine while combusting fuel in a gas column of the internal combustion engine and then generating engine torque, and to determine whether or not there is a possibility that tooth beating sound is generated in the gear mechanism on the basis of time sequence of the duration.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to the control of an internal combustion engine mounted on a vehicle as a power source and a rotating electric machine mechanically connected thereto, and particularly to the control of the internal combustion engine while it is firing. [Background technology]

[0002] Recently, hybrid vehicles equipped with two power sources, an internal combustion engine and a rotating electric machine (electric motor), have become popular. In a series hybrid vehicle (see, for example, the following patent document), an internal combustion engine drives a power-generating motor generator, which is a rotating electric machine, to generate electricity. 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 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 to propel the vehicle.

[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 rotation of the internal combustion engine may be stopped continuously.

[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. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-156134 Summary of the Invention [Problem to be solved by the invention]

[0008] As shown schematically in FIG. 6, a gear mechanism 7 is interposed between the internal combustion engine and the rotating electric machine, mechanically connecting the rotating shafts of the two. When the internal combustion engine is firing, the internal combustion engine outputs engine torque, which is transmitted to the rotating electric machine via the gear mechanism 7, thereby rotating the rotating electric machine. The rotating electric machine basically operates as a generator. At this time, as shown in FIG. 6(A), gear 71 on the internal combustion engine side serves as a drive gear, and gear 72 on the rotating electric machine side serves as a driven gear, with the teeth of the former gear 71 pushing against the teeth of the latter gear 72.

[0009] If the fuel burns properly in the cylinders after firing begins, the rotation speed of the internal combustion engine (or rotating electrical machine) can be controlled to its target value without any problems. However, if the fuel combustion becomes unstable or a misfire occurs, there is a risk of the rotation speed dropping. In such cases, the amount of power generated by the rotating electrical machine is reduced, and the load torque on the internal combustion engine is reduced in order to prevent the rotation speed of the internal combustion engine from dropping.

[0010] The actual load torque of the rotating electric machine on the internal combustion engine is not always constant, but fluctuates up and down. For this reason, when the amount of power generation is reduced, there may be an instant when the load torque becomes zero. If this happens, a gap will be created between the teeth of gear 71 on the internal combustion engine side and the teeth of gear 72 on the rotating electric machine side, as shown in Figure 6(B). Immediately after this, the load torque again becomes greater than zero, and the state transitions to Figure 6(A), where the teeth of the former gear 71 abut against the teeth of the latter gear 72.

[0011] If this occurs repeatedly, the teeth of gear 71 and the teeth of gear 72 will repeatedly strike each other. This tooth-clash noise may be transmitted to the vehicle interior as an abnormal noise or vibration that can be perceived by the vehicle occupants, including the driver. This phenomenon leads to a deterioration in the NV (Noise and Vibration) performance of the vehicle.

[0012] The present invention has been made with the above-mentioned problems in mind for the first time, and has as its intended object to accurately detect the occurrence of abnormal noise or vibration in a gear mechanism during firing of an internal combustion engine. [Means for solving the problem]

[0013] In the present invention, a control device controls an internal combustion engine and a rotating electric machine connected to the internal combustion engine via a gear mechanism, and during firing, which burns fuel in the cylinders of the internal combustion engine to generate engine torque and rotate the rotating electric machine, repeatedly measures the time required for the output shaft of the internal combustion engine to rotate a unit angle, and determines whether or not there is a possibility of gear rattle noise occurring in the gear mechanism based on the time series of the required time.The control device is configured to calculate the difference between the maximum and minimum values ​​in the time series of the change in the time required for the output shaft of the internal combustion engine to rotate a unit angle, and determine that there is a possibility of gear rattle noise occurring if the absolute value of the difference falls below a judgment threshold value a certain number of times or more within the most recent specified period, or if this has continued within the most recent specified period. Further, in the present invention, there is provided a control device for controlling an internal combustion engine and a rotating electric machine connected to the internal combustion engine via a gear mechanism, wherein, during firing, which rotates the rotating electric machine while burning fuel in a cylinder of the internal combustion engine to generate engine torque, the time required for an output shaft of the internal combustion engine to rotate by a unit angle is repeatedly measured, and whether or not there is a possibility of gear rattle noise occurring in the gear mechanism is determined based on a time series of the required time, and the control device determines whether or not there is a possibility of gear rattle noise occurring in the gear mechanism on the condition that a local maximum value in the time series of the amount of change in the time required for the output shaft of the internal combustion engine to rotate by a unit angle has fallen below an upper determination threshold a certain number of times or more within a most recent specified period, or has continued to fall below an upper determination threshold within a most recent specified period, and / or The value is lower than the upper threshold The control device is configured to determine that there is a possibility of rattle noise occurring if the lower determination threshold has been exceeded a certain number of times or more within the most recent specified period or if this has continued within the most recent specified period.

[0014] If it is determined that there is a possibility of gear rattle noise occurring in the gear mechanism, it is preferable to subsequently increase the amount of air taken into the cylinders of the internal combustion engine and the amount of fuel injected compared to before the determination. [Effects of the Invention]

[0015] According to the present invention, it is possible to accurately detect the occurrence of abnormal noise or vibration in a gear mechanism connecting an internal combustion engine and a rotating electrical machine while the internal combustion engine is firing. [Brief explanation of the drawings]

[0016] [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] 2 is a diagram showing an outline of an internal combustion engine mounted on the hybrid vehicle of the embodiment; FIG. [Figure 3] 3 is a diagram showing divisions of required outputs of a traction motor generator mounted on the hybrid vehicle of the embodiment; FIG. [Figure 4] 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 5] FIG. 4 is a timing chart for explaining the contents of a determination process performed by the control device of the embodiment. [Figure 6] FIG. 2 is a diagram schematically showing a gear mechanism interposed between an internal combustion engine and a rotating electric machine. DETAILED DESCRIPTION OF THE INVENTION

[0017] 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 a supply of electric power from the power generation motor / generator 2 and / or the power storage device 3 to drive drive wheels 62 of the vehicle.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] FIG. 2 shows an overview of an internal combustion engine 1 mounted on a hybrid vehicle of this embodiment. The internal combustion engine 1 is, for example, a spark-ignition four-stroke reciprocating engine and includes a plurality of cylinders 11 (for example, three cylinders, one of which is shown in FIG. 2). An injector 111 that injects fuel toward the intake port is provided near the intake port of each cylinder 11. In addition, 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.

[0026] 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.

[0027] 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 an intake passage 13 (particularly, a surge tank 133 or an intake manifold 134) connected to a 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 for the internal combustion engine 1, an atmospheric pressure signal f output from an atmospheric pressure sensor that detects the atmospheric pressure, 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. The signal g output from the pressure sensor that detects the pressure in the constant pressure chamber of the brake booster 15 and thus the magnitude of the negative pressure stored in the constant pressure chamber is input.

[0028] 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.

[0029] 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.

[0030] Figure 3 shows the relationship between the output required by the vehicle driver and whether or not the internal combustion engine 1 and the electricity-generating motor-generator 2 need to be operated. The output required from the traction motor-generator 4 is determined by the amount of accelerator pedal depression 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. The required output increases toward the upper right in Figure 3.

[0031] In low output range I, 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 firing 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 low output range I, 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 I typically occurs when the accelerator opening is 0 or below a predetermined value, or when the vehicle is decelerating.

[0032] In medium-to-high output ranges II and III, 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-to-high output range II, 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 vehicle travel. At this time, the power storage device 3 supplies only a small amount of power or no power at all. In the high-to-high output range III, 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 vehicle travel.

[0033] 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.

[0034] When fuel is not being supplied to the cylinders 11 of the internal combustion engine 1 to operate the internal combustion engine 1, and the drive wheels 62 are being driven by the traction motor-generator 4 to run the vehicle, in order to start the internal combustion engine 1 and generate electricity with the power-generating motor-generator 2, the power-generating motor-generator 2 is first operated as an electric motor to perform motoring to start the internal combustion engine 1. Then, once the crankshaft of the internal combustion engine 1 has rotated a predetermined number of times or a predetermined angle or more and cylinder discrimination has been completed to determine the current stroke or piston position of each cylinder 11 of the internal combustion engine 1, fuel is injected at an appropriate timing in accordance with the stroke of each cylinder 11 of the internal combustion engine 1, and firing is started to ignite and burn the fuel at the appropriate timing. The rotation angle and rotation speed of the crankshaft of the internal combustion engine 1, or the rotation angle and rotation speed of the rotating shaft of the power generation motor generator 2 (the rotation speed of the power generation motor generator 2 is proportional to the rotation speed of the internal combustion engine 1, and the proportionality constant is known) can be detected (in the EFI ECU 01) via a crank angle sensor attached to the internal combustion engine 1, or can also be detected (in the PCU (or MG ECU) 02) via a resolver attached to the power generation motor generator 2.

[0035] When the internal combustion engine 1 is able to rotate independently and output the rotational drive force required for power generation, and the engine speed can maintain an upward trend even when the output of the power-generating motor-generator 2 is reduced, the output of the power-generating motor-generator 2, which is operating as an electric motor, is reduced to 0 to end motoring, and the power-generating motor-generator 2 is then driven to rotate by the internal combustion engine 1. Furthermore, the power-generating motor-generator 2 is operated as a generator, and its generated power is increased from 0.

[0036] Thereafter, the amount of intake air and fuel injection supplied to the cylinders 1 of the internal combustion engine 1, as well as the power generated by the power-generating motor-generator 2, are adjusted to increase or decrease so that the engine speed follows the target speed that is increased in stages. The final target speed is set to the speed that allows the internal combustion engine 1 to operate at optimum or near-optimum efficiency and is most advantageous in terms of fuel consumption rate, or the speed at which the internal combustion engine 1 can achieve maximum torque or maximum output or torque or output close to this.

[0037] The EFI ECU01, which is part of the control device 0, acquires various pieces of information b, d, e, and f required for controlling the operation 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. Then, it determines operating 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 a required EGR rate (or EGR gas amount). The EFI ECU01 outputs various control signals i, j, k, and l corresponding to the operating parameters via an output interface to an igniter of the spark plug 112, the injector 111, the throttle valve 132, the EGR valve 123, and the like.

[0038] When the driver depresses the accelerator pedal to start the vehicle from a stopped or low-speed state where the vehicle is nearly stopped, the required output of the traction motor / generator 4 transitions from low output region I to medium-high output region II or III, causing the internal combustion engine 1, which had been stopped up until then, to start.Also, the internal combustion engine 1 will start when the amount of charge (SOC) stored in the electricity storage device 3 falls below a predetermined value or when the negative pressure stored in the constant pressure chamber of the brake booster 15 falls below a predetermined value.

[0039] 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.

[0040] 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.

[0041] If the control device 0 of this embodiment detects unstable fuel combustion or a misfire in the cylinder 11 of the internal combustion engine 1 while the internal combustion engine 1 is firing and rotating the power-generating motor-generator 2 to generate electricity, it reduces the target output of the power-generating motor-generator 2 from the previous level, thereby reducing the load torque on the internal combustion engine 1 by the power-generating motor-generator 2. This is a measure to avoid engine stall.

[0042] Then, as shown in FIG. 4, when the control device 0 continues to generate electricity by reducing the load torque of the power generation motor generator 2 from normal (step S1), it determines whether or not gear rattle noise occurs in the gear mechanism 7 connecting the internal combustion engine 1 and the power generation motor generator 2 based on fluctuations in the rotational speed of the internal combustion engine 1 (step S2).

[0043] The rotational speed of the crankshaft, which is the output shaft of the internal combustion engine 1, can be determined by referring to the output signal b of the crank angle sensor. As is well known, the crank angle sensor senses the rotation angle of a rotor that is fixed to the end of the crankshaft and rotates integrally with the crankshaft. Teeth or protrusions are formed on the rotor in advance at predetermined angles (typically, every 10° CA (crank angle)) along the rotational direction of the crankshaft. The crank angle sensor faces the outer periphery of the rotor and detects each tooth or protrusion passing near the sensor, transmitting a pulse signal each time. The EFI ECU 01, which is part of the control device 0, receives this pulse as the crank angle signal b.

[0044] The control device 0 (or the EFI ECU 01) originally constantly monitors the rotation speed of the crankshaft of the internal combustion engine 1 by referring to the crank angle signal b. Specifically, by referring to the pulse train of the crank angle signal b, it repeatedly measures the time required for the crankshaft to rotate a predetermined crank angle, typically 30° CA. At the same time, by subtracting the required time measured previously from the required time measured this time, it obtains the amount of change in the required time for 30° CA, which is an index of the amount of change (decrease) in the rotation speed for every 30° CA. A positive value for the amount of change in the required time for 30° CA means that the rotation speed of the internal combustion engine 1 is tending to decrease (deceleration), and a negative value means that the rotation speed of the internal combustion engine is tending to increase (acceleration).

[0045] The rotational speed of the crankshaft per 30° CA or the time required for each 30° CA is not always constant, but is fastest during the expansion stroke of each cylinder 11 and slowest midway between the expansion stroke of one cylinder 11 and the expansion stroke of the next cylinder 11.

[0046] The control device 0 performs feedback control to make the rotation speed of the internal combustion engine 1 follow a target value, as well as feedback control to make the load torque of the power generation motor generator 2 follow a target value, but in accordance with this, the magnitude of the load torque also fluctuates up and down depending on the situation. If the load torque of the power generation motor generator 2 is reduced more than usual (step S1), there may be an instant when the load torque becomes zero, which may cause gear rattle noise in the gear mechanism 7.

[0047] FIG. 5 shows the transition of the time required for the crankshaft of the internal combustion engine 1 to rotate 30° CA. The thin solid line represents a situation where there is little or no possibility of gear rattle occurring in the gear mechanism 7. The thick dashed line represents a situation where there is a possibility of gear rattle occurring in the gear mechanism 7. A situation where gear rattle occurs is when the load torque of the power-generator motor-generator 2 becomes zero, and a gap occurs between the teeth of the gear 71 on the internal combustion engine 1 side and the teeth 72 on the power-generator motor-generator 2 side. When the mechanical load of the power-generator motor-generator 2 on the internal combustion engine 1 is extremely small, the drop in the rotational speed of the internal combustion engine 1 that drives it becomes small, and the range of fluctuation in the time required for 30° CA becomes small, as shown by the thick dashed line in FIG. 5.

[0048] In step S2, the control device 0 performs, for example, The difference between the maximum and minimum values ​​of the time series of the amount of change in the required time for the 30° CA described above is calculated, and if the absolute value of this difference falls below the judgment threshold value, it is determined that there is a possibility of rattle noise occurring if this has occurred a certain number of times or more within the most recent specified period or if this has continued within the most recent specified period. The possibility of occurrence of rattle noise is determined based on the condition that the maximum value of the time series of the amount of change in the time required for 30° CA described above falls below the upper judgment threshold a certain number of times or continues within the most recent specified period, and / or the minimum value of the time series of the amount of change in the time required for 30° CA described above exceeds the lower judgment threshold (a value lower than the upper judgment threshold) a certain number of times or continues within the most recent specified period. Having determined that there is a possibility of teeth rattle noise occurring, the control device 0 then increases the opening of the throttle valve 132 of the internal combustion engine 1 to increase the amount of intake air into the cylinder 11, and also increases the amount of fuel injected from the injector 11, thereby implementing correction control to increase engine torque (step S3). This prevents the teeth of the gear 71 on the internal combustion engine 1 side from separating from the teeth on the electricity-generating motor-generator 2 side, making it possible to prevent repeated occurrence of teeth rattle noise.

[0049] According to this embodiment, the problem of the teeth of the gear 72 on the rotating electric machine 2 side repeatedly striking against the teeth of the gear 71 on the internal combustion engine 1 side can be effectively avoided, which can contribute to further improving the NV performance of the vehicle. Furthermore, the method of this embodiment can be realized simply by modifying the program (control logic) of the control device 0. There is no need to add sound-absorbing materials or other new hardware, so there is no risk of a rise in costs.

[0050] The present invention is not limited to the above-described embodiment, and for example, the application of the present invention is not limited to series hybrid vehicles.

[0051] 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]

[0052] 0...Control unit (ECU) 1...Internal combustion engine 11...cylinder 111...Injector 13...Intake passage 132...Throttle valve 2... Rotating electric machine (motor generator for power generation) 7...Gear mechanism 71... Gear on the internal combustion engine side 72...Gear on the rotating electrical machine side

Claims

1. A control device for controlling an internal combustion engine and a rotating electric machine connected to the internal combustion engine via a gear mechanism, During firing, which rotates the rotating electric machine while burning fuel in a cylinder of the internal combustion engine to generate engine torque, the time required for an output shaft of the internal combustion engine to rotate by a unit angle is repeatedly measured, and based on a time series of the required time, it is determined whether or not there is a possibility of gear rattle noise occurring in the gear mechanism; The control device calculates the difference between the maximum and minimum values ​​of a time series of the amount of change in the time required for the output shaft of the internal combustion engine to rotate a unit angle, and determines that there is a possibility of gear rattle noise occurring if the absolute value of this difference falls below a judgment threshold value either a certain number of times or continuously within the most recent specified period.

2. A control device for controlling an internal combustion engine and a rotating electric machine connected to the internal combustion engine via a gear mechanism, During firing, which rotates the rotating electric machine while burning fuel in a cylinder of the internal combustion engine to generate engine torque, the time required for an output shaft of the internal combustion engine to rotate by a unit angle is repeatedly measured, and based on a time series of the required time, it is determined whether or not there is a possibility of gear rattle noise occurring in the gear mechanism; determining that there is a possibility of occurrence of gear rattle noise when a time series maximum value of the amount of change in the time required for the output shaft of the internal combustion engine to rotate by a unit angle falls below an upper determination threshold value a certain number of times or more within a recent specified period, or when this has continued within a recent specified period; or A control device that determines that there is a possibility of gear rattle noise occurring if the minimum value of the time series of the amount of change in the time required for the output shaft of the internal combustion engine to rotate a unit angle exceeds a lower judgment threshold, which is a value lower than an upper judgment threshold, a certain number of times or more within the most recent specified period, or if this occurs continuously within the most recent specified period.

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