JP7703939B2 - Hybrid vehicles - Google Patents

Description

The present invention relates to a hybrid vehicle.

A conventional hybrid vehicle of this type has been proposed in which a first motor and an engine are connected to the sun gear and carrier of a planetary gear, a drive gear formed integrally with the ring gear of the planetary gear is connected to the drive wheels via a driven gear, a second motor is connected to the driven gear, and the first motor and second motor are driven by an inverter (see, for example, Patent Document 1). In this hybrid vehicle, when the shift position is in the parking position and the engine is idling, the first motor and second motor eliminate backlash in the gear mechanism in the power transmission path from the drive gear to the drive wheels, thereby suppressing the generation of gear rattle noise in the gear mechanism.

JP 2018-118677 A

In such hybrid vehicles, when the shift position is in neutral, the inverter gate is shut off, so the first motor and second motor cannot eliminate backlash in the gear mechanism. This can result in a relatively loud rattle noise in the gear mechanism due to engine torque pulsation.

The primary objective of the hybrid vehicle of the present invention is to suppress the relatively loud gear rattle noise that occurs in the gear mechanism.

The hybrid vehicle of the present invention employs the following means to achieve the above-mentioned main objective.

The hybrid vehicle of the present invention is
An engine connected to drive wheels via a gear mechanism;
a motor connected to the engine;
an inverter that drives the motor;
a control device that controls the inverter so that the motor eliminates backlash in the gear mechanism when the shift position is not in the neutral position, and that shuts off a gate of the inverter when the shift position is in the neutral position;
A hybrid vehicle comprising:
When the shift position is the neutral position during idling of the engine, the control device controls the engine so that the engine is idled at a higher rotation speed than when the shift position is not the neutral position.
The gist of the present invention is as follows.

In the hybrid vehicle of the present invention, when the shift position is not in the neutral position, the inverter is controlled so that the motor eliminates backlash in the gear mechanism, and when the shift position is in the neutral position, the inverter is gated off. In this case, when the engine is idling, when the shift position is in the neutral position, the engine is controlled so that the engine idles at a higher speed than when the shift position is not in the neutral position. This makes it possible to suppress engine torque pulsation by increasing the primary explosion frequency of the engine (shortening the period of explosive combustion) when the engine is idling with the shift position in the neutral position. As a result, it is possible to suppress the generation of relatively loud rattle noise in the gear mechanism connected to the engine.

In the hybrid vehicle of the present invention, the control device may control the engine so that when the engine is idling with the shift position in the neutral position, when the vehicle speed is high, the engine is idling at a lower rotation speed than when the vehicle speed is low. This is because when the vehicle speed is high, gear rattle noise that may occur in the gear mechanism blends in with road noise and is less noticeable to the driver than when the vehicle speed is low.

1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention; 2 is a diagram showing an outline of the configuration of an electric drive system including motors MG1 and MG2. FIG. 4 is a flowchart showing an example of an idle operation control routine executed by an HVECU 70.

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 according to one embodiment of the present invention, and Figure 2 is a schematic diagram showing the configuration of an electric drive system including motors MG1 and MG2. As shown in the figure, the hybrid vehicle 20 according to the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery (electricity storage device) 50, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

The engine 22 is configured as an internal combustion engine that outputs power using gasoline, diesel, or the like as fuel, and the crankshaft 23 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28. The operation of this engine 22 is controlled by an engine electronic control unit (hereinafter referred to as the "engine ECU") 24.

The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via the input port. Examples of signals input to the engine ECU 24 include the crank angle θcr from the crank position sensor 23a that detects the rotational position of the crankshaft 23 of the engine 22, and the cooling water temperature Tw from a water temperature sensor that detects the temperature of the cooling water of the engine 22. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via the output port. Examples of signals output from the engine ECU 24 include a control signal to a throttle valve, a control signal to a fuel injection valve, and a control signal to an ignition plug. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr from the crank position sensor 23a.

The planetary gear 30 is configured as a single-pinion type planetary gear mechanism. The rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. The ring gear of the planetary gear 30 is connected to the drive shaft 36 which is connected to the drive wheels 39a, 39b via a differential gear 38. As described above, the crankshaft 23 of the engine 22 is connected to the carrier of the planetary gear 30.

Motor MG1 is configured as a synchronous generator motor having a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core, and as described above, the rotor is connected to the sun gear of planetary gear 30. Motor MG2 is configured as a synchronous generator motor like motor MG1, and the rotor is connected to drive shaft 36.

The inverters 41 and 42 are used to drive the motors MG1 and MG2 and are connected to the power line 54. As shown in FIG. 2, the inverter 41 has six transistors T11 to T16 as switching elements and six diodes D11 to D16 connected in parallel to the six transistors T11 to T16. The transistors T11 to T16 are arranged in pairs of two, one on the source side and the other on the sink side of the positive and negative lines of the power line 54. In addition, each of the three-phase coils (U-phase, V-phase, and W-phase) of the motor MG1 is connected to each of the connection points of the pair of transistors T11 to T16. Therefore, when a voltage is applied to the inverter 41, the motor electronic control unit (hereinafter referred to as the "motor ECU") 40 adjusts the ratio of the on time of the pair of transistors T11 to T16, forming a rotating magnetic field in the three-phase coils and driving the motor MG1 to rotate. Like inverter 41, inverter 42 has six transistors T21 to T26 and six diodes D21 to D26. When a voltage is applied to inverter 42, motor ECU 40 adjusts the ratio of on-time of paired transistors T21 to T26, forming a rotating magnetic field in the three-phase coil and driving motor MG2 to rotate.

The motor ECU 40 is equipped with a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. Signals from various sensors necessary for driving and controlling the motors MG1 and MG2 are input to the motor ECU 40 via the input ports. Examples of signals input to the motor ECU 40 include rotational positions θm1 and θm2 from rotational position sensors (e.g., resolvers) 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and phase currents Iu1, Iv1, Iu2, and Iv2 from current sensors that detect the phase currents flowing through each phase of the motors MG1 and MG2. The motor ECU 40 outputs switching control signals to the transistors T11 to T16 and T21 to T26 of the inverters 41 and 42 via the output ports. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 calculates the electrical angles θe1, θe2 and rotation speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position sensors 43, 44.

The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery, and as described above, is connected to the inverters 41, 42 via a power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as the "battery ECU") 52.

Although not shown, the battery ECU 52 is equipped with a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. Signals from various sensors required for managing the battery 50 are input to the battery ECU 52 via the input port. Examples of signals input to the battery ECU 52 include a voltage Vb from a voltage sensor 50a attached between the terminals of the battery 50 and a current Ib from a current sensor 50b attached to the output terminal of the battery 50. The battery ECU 52 is connected to the HVECU 70 via the communication port. The battery ECU 52 calculates the power storage ratio SOC based on the integrated value of the current Ib of the battery 50 from the current sensor 50b. The power storage ratio SOC is the ratio of the amount of power that can be discharged from the battery 50 to the total capacity of the battery 50.

Although not shown, the HVECU 70 is equipped with a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. Signals from various sensors are input to the HVECU 70 via the input ports. Examples of signals input to the HVECU 70 include an ignition signal from an ignition switch 80 and a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81. Examples of signals input to the HVECU 70 include an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87. Examples of the shift position SP include a parking position (P position) used when parking, a reverse position (R position) for reverse driving, a neutral position (N position), and a forward position (D position) for forward driving. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via communication ports.

In the hybrid vehicle 20 of the embodiment thus configured, the engine 22 and motors MG1, MG2 (inverters 41, 42) are controlled by cooperative control between the HVECU 70, engine ECU 24, and motor ECU 40 so that the vehicle runs with a running torque Td* based on the accelerator opening Acc and vehicle speed V in a hybrid running (HV running) mode in which the vehicle runs with the engine 22 running, or in an electric running (EV running) mode in which the vehicle runs with the engine 22 stopped. When the required power Pe* of the engine 22 based on the running torque Td* is sufficiently small and there is a request to warm up the engine 22 or heat the vehicle interior, the engine 22 is idled.

In addition, in the hybrid vehicle 20 of the embodiment, when the shift position is the N position, the gates of the inverters 41 and 42 are shut off (all of the transistors T11 to T16 and T21 to T26 are turned off). In this case, when the engine 22 is operating immediately before the shift position SP is shifted to the N position, the engine 22 is put into idle operation.

Next, the operation of the hybrid vehicle 20 of the embodiment, particularly the operation when the engine 22 is idling, will be described. FIG. 3 is a flowchart showing an example of an idle operation control routine executed by the HVECU 70. This routine is executed repeatedly when the engine 22 is idling.

When the idle operation control routine of FIG. 3 is executed, the HVECU 70 first inputs data such as the shift position SP and the vehicle speed V (step S100). Here, the shift position SP is detected and input by the shift position sensor 82. The vehicle speed V is detected and input by the vehicle speed sensor 87.

When the data is input in this way, it is determined whether the input shift position SP is the N position (step S110). This process is a process for determining whether the inverters 41, 42 are gate-blocked. When it is determined that the shift position SP is not the N position, it is determined that the inverters 41, 42 are not gate-blocked, and the target rotation speed Ne* of the engine 22 is set to the rotation speed Ne1 (step S130), and an idle operation command and the target rotation speed Ne* of the engine 22 are sent to the engine ECU 24, and a backlash-eliminating command is sent to the motor ECU 40 (step S140), and this routine is terminated. Here, for example, about 900 rpm to 1100 rpm is used as the rotation speed Ne1. When the engine ECU 24 receives the idle operation command and the target rotation speed Ne* of the engine 22, it performs operation control of the engine 22 (intake air amount control, fuel injection control, ignition control, etc.) so that the engine 22 idles at the target rotation speed Ne*. When the motor ECU 40 receives a backlash elimination command, it controls the motor MG1 (inverter 41) so that the motor MG1 eliminates backlash in the gear mechanism, such as the planetary gear 30.

When it is determined in step S110 that the shift position SP is the N position, it is determined that the inverters 41, 42 are gated off, and it is determined whether the vehicle speed V is equal to or lower than the threshold value Vref (step S120). When the inverters 41, 42 are gated off during idling of the engine 22, the motors MG1, MG2 cannot eliminate the backlash of the gear mechanism such as the planetary gear 30. For this reason, if no measures are taken, the gear mechanism may generate a relatively loud rattle due to torque pulsation caused by idling of the engine 22. When the vehicle speed V is low (including when the vehicle is stopped), the road noise is relatively small, so the driver is more likely to feel the rattle that may occur in the gear mechanism, and when the vehicle speed V is high, the road noise is relatively large, so the driver is less likely to feel the rattle. Taking these factors into consideration, the threshold value Vref is a threshold value used to determine the degree of likelihood that the driver will hear the gear rattle noise that may occur in the gear mechanism due to torque pulsation of the engine 22 when the engine 22 is idling, and is, for example, about several tens of km/h.

When it is determined in step S120 that the vehicle speed V is equal to or lower than the threshold value Vref, it is determined that there is a sufficient possibility that the driver will hear the rattle noise that may occur in the gear mechanism such as the planetary gear 30, and the target rotation speed Ne* of the engine 22 is set to a rotation speed Ne2 higher than the rotation speed Ne1 (step S150), an idle operation command and the target rotation speed Ne* of the engine 22 are sent to the engine ECU 24 (step S170), and this routine is terminated. Here, the rotation speed Ne2 is set to a rotation speed that is several hundred rpm higher than the rotation speed Ne1. In this way, by setting the target rotation speed Ne* of the engine 22 to a rotation speed Ne2 higher than the rotation speed Ne1 and operating the engine 22 in an idle operation, the primary explosion frequency (period of explosive combustion) of the engine 22 can be increased to suppress the torque pulsation of the engine 22. As a result, it is possible to suppress the generation of relatively large rattle noise in the gear mechanism such as the planetary gear 30, and to suppress the driver from feeling the rattle noise.

When it is determined in step S120 that the vehicle speed V is higher than the threshold value Vref, it is determined that the possibility that the driver will hear the rattle noise that may occur in the gear mechanism is sufficiently low, and the target rotation speed Ne* of the engine 22 is set to a rotation speed Ne3 lower than the rotation speed Ne2 (step S160), an idle operation command and the target rotation speed Ne* of the engine 22 are sent to the engine ECU 24 (step S170), and this routine ends. Here, the rotation speed Ne3 is, for example, the same as the rotation speed Ne1 or a rotation speed slightly higher than the rotation speed Ne1. In this way, by setting the target rotation speed Ne* of the engine 22 to a rotation speed Ne3 lower than the rotation speed Ne2 and idling the engine 22, it is possible to suppress the fuel consumption of the engine 22.

In the hybrid vehicle 20 of the embodiment described above, when the engine 22 is idling, when the shift position SP is in the N position and the vehicle speed V is equal to or lower than the threshold value Vref, the engine 22 is controlled so that the engine 22 idles at a higher speed than when the shift position SP is not in the N position or when the shift position SP is in the N position and the vehicle speed V is higher than the threshold value Vref. This makes it possible to suppress the relatively loud rattle noise generated by the gear mechanism such as the planetary gear 30, and to suppress the driver from feeling the rattle noise.

In the hybrid vehicle 20 of the embodiment, when the shift position SP is in the N position and the engine 22 is idling, if the vehicle speed V is equal to or lower than the threshold value Vref, the target rotation speed Ne* of the engine 22 is set to the rotation speed Ne2 and the engine 22 is idling, and if the vehicle speed V is higher than the threshold value Vref, the target rotation speed Ne* of the engine 22 is set to the rotation speed Ne3, which is lower than the rotation speed Ne2, and the engine 22 is idling. However, when the shift position SP is in the N position and the engine 22 is idling, the target rotation speed Ne* of the engine 22 may be set to be lower as the vehicle speed V increases, and the engine 22 may be idling. Also, when the shift position SP is in the N position and the engine 22 is idling, the target rotation speed Ne* of the engine 22 may be set to the rotation speed Ne2 and the engine 22 may be idling, regardless of the vehicle speed V.

In the hybrid vehicle 20 of the embodiment, when the engine 22 is idled with the shift position SP in a position other than N, the motor MG1 is used to eliminate backlash in the gear mechanism, such as the planetary gear 30. However, when the motor MG1 cannot eliminate backlash in the gear mechanism due to conditions such as the charge rate SOC of the battery 50, the engine 22 may be set to the rotation speed Ne2 or Ne3 depending on the vehicle speed V, or may be set to the rotation speed Ne2 regardless of the vehicle speed V.

In the hybrid vehicle 20 of the embodiment, when the engine 22 is idling with the shift position SP in a position other than N, the gear mechanism, including the planetary gear 30, is eliminated by the motor MG1. However, the gear mechanism may be eliminated by the motor MG2, or by both the motors MG1 and MG2. When the shift position SP is in the D or R position, the motor MG2 is basically driven for power or regenerative driving based on the driving torque Td*, which is based on the accelerator opening Acc and the vehicle speed V, and this is thought to eliminate the backlash in the gear mechanism.

In the hybrid vehicle 20 of the embodiment, the engine 22 and motor MG1 are connected via the planetary gear 30 to the drive shaft 36 connected to the drive wheels 39a, 39b, and the motor MG2 is connected to the drive shaft 36, and the motors MG1, MG2 are driven by the inverters 41, 42. However, the present invention is not limited to this, and any configuration can be used as long as the motor can eliminate backlash in the gear mechanism between the engine and the drive wheels. For example, the engine may be connected via a transmission and a clutch to the drive shaft connected to the drive wheels, and the motor may be connected to either the engine side or the drive wheel side of the transmission, and driven by the inverter.

The following explains the relationship between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem. In the embodiment, the engine 22 corresponds to the "engine", the motors MG1 and MG2 correspond to the "motors", and the HVECU 70, the engine ECU 24, and the motor ECU 40 correspond to the "control device".

The correspondence between the main elements of the Examples and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the Examples are examples for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Means for Solving the Problem column.

The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the invention.

The present invention can be used in the hybrid vehicle manufacturing industry, etc.

20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 23a Crank position sensor, 24 Engine ECU, 28 Damper, 30 Planetary gear, 36 Drive shaft, 38 Differential gear, 39a, 39b Drive wheels, 40 Motor ECU, 41, 42 Inverter, 43, 44 Rotational position sensor, 50 Battery, 50a Voltage sensor, 50b Current sensor, 52 Battery ECU, 54 Power line, 70 HV ECU, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 87 Vehicle speed sensor, D11 to D16, D21 to D26 Diodes, D21 Diode, MG1, MG2 Motor, T11-T16, T21-T26 transistors.

Claims (1)

An engine connected to drive wheels via a gear mechanism;
a motor connected to the engine;
an inverter that drives the motor;
a control device that controls the inverter so that the motor eliminates backlash in the gear mechanism when the shift position is not in the neutral position, and that shuts off a gate of the inverter when the shift position is in the neutral position;
A hybrid vehicle comprising:
When the engine is operated at idle, the control device
When the shift position is not the neutral position, the engine is controlled so as to idle at a first rotation speed;
When the shift position is the neutral position and the vehicle speed is equal to or lower than a threshold value, the engine is controlled so as to idle at a second rotation speed that is higher than the first rotation speed;
When the shift position is the neutral position and the vehicle speed is higher than the threshold value, the engine is controlled so as to idle at a third rotation speed which is lower than the second rotation speed and equal to or higher than the first rotation speed.
Hybrid car.

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