Hybrid vehicle

Abstract

To suppress the generation of a relatively large tooth-clattering noise in a gear mechanism.SOLUTION: When a shift position is not in a neutral position, an inverter is controlled so as to decrease a play in a gear mechanism by a motor, whereas when the shift position is at a neutral position, the inverter is gate-shut off. In this case, if the shift position is at the neutral position when idle-driving an engine, the engine is controlled to idle-operate at a higher revolution than in the case of the shift position being not at the neutral position.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a hybrid vehicle.

Background Art

[0002] Conventionally, as this type of hybrid vehicle, a first motor and an engine are connected to the sun gear and the carrier of a planetary gear, a drive gear integrally formed with the ring gear of the planetary gear is connected to drive wheels via a driven gear, a second motor is connected to the driven gear, and an inverter drives the first motor and the second motor (see, for example, Patent Document 1). In this hybrid vehicle, when the engine is idling with the shift position in the parking position, backlash of the gear mechanism in the power transmission path from the drive gear to the drive wheels is eliminated by the first motor or the second motor, thereby suppressing the generation of meshing noise in the gear mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a hybrid vehicle, when the shift position is in the neutral position, since the gate of the inverter is cut off, backlash of the gear mechanism cannot be eliminated by the first motor or the second motor. Therefore, relatively large meshing noise may occur in the gear mechanism due to torque pulsation of the engine.

[0005] The main object of the hybrid vehicle of the present invention is to suppress the generation of relatively large meshing noise in the gear mechanism.

Means for Solving the Problems

[0006] The hybrid vehicle of the present invention adopts the following means to achieve the above-mentioned main object.

[0007] The hybrid vehicle of the present invention includes an engine connected to drive wheels via a gear mechanism, a motor connected to the engine, an inverter for driving the motor, and a control device that controls the inverter so that the backlash of the gear mechanism is eliminated by the motor when the shift position is not in the neutral position, and shuts off the gate of the inverter when the shift position is in the neutral position. The hybrid vehicle is provided with wherein the control device controls the engine so that when the shift position is in the neutral position during idling of the engine, the engine is idled at a higher rotational speed than when the shift position is not in the neutral position. This is the gist.

[0008] 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 backlash of the gear mechanism is eliminated by the motor, and when the shift position is in the neutral position, the gate of the inverter is shut off. In this case, when the engine is idling, when the shift position is in the neutral position, the engine is controlled so that it is idled at a higher rotational speed than when the shift position is not in the neutral position. Thereby, when the engine is idling with the shift position in the neutral position, the primary frequency of the engine explosion can be increased (the cycle of the explosion combustion can be shortened) to suppress the torque pulsation of the engine. As a result, it is possible to suppress the generation of a relatively large meshing noise in the gear mechanism connected to the engine.

[0009] In the hybrid vehicle of the present invention, when the control device idles the engine with the shift position in the neutral position, when the vehicle speed is high, the engine may be controlled to idle at a lower rotational speed than when the vehicle speed is low. This is based on the fact that when the vehicle speed is high, the meshing noise that can occur in the gear mechanism is masked by the road noise compared to when the vehicle speed is low, making it less likely for the driver to feel the meshing noise.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0011] Next, embodiments for carrying out the present invention will be described using examples.

Examples

[0012] FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention, and FIG. 2 is a configuration diagram showing an outline of the configuration of an electric motor drive system including motors MG1 and MG2. As shown in the figure, the hybrid vehicle 20 of the example includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery (power storage device) 50, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0013] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel oil. The crankshaft 23 of the engine 22 is connected to the carrier of the planetary gear 30 via the damper 28. This engine 22 is operationally controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0014] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors necessary for operationally controlling the engine 22 are input into the engine ECU 24 via the input ports. Examples of the signals input into the engine ECU 24 include the crank angle θcr from a crank position sensor 23a that detects the rotational position of the crankshaft 23 of the engine 22, and the coolant temperature Tw from a coolant temperature sensor that detects the temperature of the coolant of the engine 22. Various control signals for operationally controlling the engine 22 are output from the engine ECU 24 via the output ports. Examples of the 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 a spark plug. The engine ECU 24 is connected to the HV ECU 70 via the communication port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr from the crank position sensor 23a.

[0015] 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 drive shaft 36, which is connected to the drive wheels 39a and 39b via the differential gear 38, is connected to the ring gear of the planetary gear 30. As described above, the crankshaft 23 of the engine 22 is connected to the carrier of the planetary gear 30.

[0016] The motor MG1 is configured as a synchronous generator motor having a rotor with permanent magnets embedded in the rotor core and a stator with three-phase coils wound around the stator core. As described above, the rotor is connected to the sun gear of the planetary gear 30. The motor MG2 is configured as a synchronous generator motor in the same manner as the motor MG1, and the rotor is connected to the drive shaft 36.

[0017] 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 each of the six transistors T11 to T16. The transistors T11 to T16 are arranged in pairs of two each so as to be on the source side and the sink side with respect to the positive line and the negative line of the power line 54. Also, each of the connection points of the two transistors that form a pair of the transistors T11 to T16 is connected to each of the three-phase coils (U-phase, V-phase, W-phase) of the motor MG1. Therefore, when a voltage is applied to the inverter 41, the motor electronic control unit (hereinafter referred to as "motor ECU") 40 adjusts the ratio of the on-time of the paired transistors T11 to T16, thereby forming a rotating magnetic field in the three-phase coils and rotating the motor MG1. The inverter 42 has six transistors T21 to T26 and six diodes D21 to D26 in the same manner as the inverter 41. And when a voltage is applied to the inverter 42, the motor ECU 40 adjusts the ratio of the on-time of the paired transistors T21 to T26, thereby forming a rotating magnetic field in the three-phase coils and rotating the motor MG2.

[0018] The motor ECU 40 includes 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 the signals input to the motor ECU 40 include the rotational positions θm1 and θm2 from the rotational position sensors (e.g., resolvers) 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and the phase currents Iu1, Iv1, Iu2, and Iv2 from the current sensors that detect the phase currents flowing through each phase of the motors MG1 and MG2. Switching control signals, etc., to the transistors T11 to T16 and T21 to T26 of the inverters 41 and 42 are output from the motor ECU 40 via the output ports. The motor ECU 40 is connected to the HV ECU 70 via the communication port. The motor ECU 40 calculates the electrical angles θe1 and θe2 and the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position sensors 43 and 44.

[0019] The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the inverters 41 and 42 via the power line 54 as described above. This battery 50 is managed by a battery electronic control unit (hereinafter referred to as "battery ECU") 52.

[0020] Although not shown, the battery ECU 52 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input ports. Examples of the signals input to the battery ECU 52 include the voltage Vb from the voltage sensor 50a attached between the terminals of the battery 50 and the current Ib from the current sensor 50b attached to the output terminal of the battery 50. The battery ECU 52 is connected to the HV ECU 70 via the communication port. The battery ECU 52 calculates the state of charge SOC based on the integrated value of the current Ib of the battery 50 from the current sensor 50b. The state of charge SOC is the ratio of the amount of electric power that can be discharged from the battery 50 to the total capacity of the battery 50.

[0021] Although not shown, the HV ECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the HV ECU 70 via the input ports. Examples of the signals input to the HV ECU 70 include the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 that detects the operating position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed V from the vehicle speed sensor 87. Examples of the shift position SP include the parking position (P position) used when parking, the reverse position (R position) for reverse travel, the neutral position (N position), and the drive position (D position) for forward travel. As described above, the HV ECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port.

[0022] In the hybrid vehicle 20 of the embodiment configured in this way, basically, by the cooperative control of the HVECU 70, the engine ECU 24, and the motor ECU 40, in a hybrid driving (HV driving) mode that travels with the operation of the engine 22 or an electric vehicle driving (EV driving) mode that travels with the operation stop of the engine 22, the engine 22 and the motors MG1 and MG2 (inverters 41 and 42) are controlled to travel by the driving torque Td* based on the accelerator opening Acc and the vehicle speed V. When the required power Pe* of the engine 22 based on the driving torque Td* is sufficiently small, or when warm-up of the engine 22 or heating of the vehicle interior is required, the engine 22 is idled.

[0023] Also, in the hybrid vehicle 20 of the embodiment, when the shift position is in 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 being operated immediately before the shift operation to the N position of the shift position SP, the engine 22 is idled.

[0024] Next, the operation of the hybrid vehicle 20 of the embodiment, particularly the operation when idling the engine 22, 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 repeatedly executed when idling the engine 22.

[0025] 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.

[0026] When data is input in this way, it is determined whether the input shift position SP is the N position (step S110). This process is to determine whether the inverters 41 and 42 are gate-blocked. When it is determined that the shift position SP is not the N position, it is judged that the inverters 41 and 42 are not gate-blocked, the rotation speed Ne1 is set to the target rotation speed Ne* of the engine 22 (step S130), the idle operation command and the target rotation speed Ne* of the engine 22 are transmitted to the engine ECU 24, and the backlash elimination command is transmitted to the motor ECU 40 (step S140), and this routine is terminated. Here, as the rotation speed Ne1, for example, about 900 rpm to 1100 rpm is used. When the engine ECU 24 receives the idle operation command and the target rotation speed Ne* of the engine 22, it performs operation control (such as intake air amount control, fuel injection control, ignition control, etc.) of the engine 22 so that the engine 22 idles at the target rotation speed Ne*. When the motor ECU 40 receives the backlash elimination command, it controls the motor MG1 (inverter 41) so that the backlash of the gear mechanism such as the planetary gear 30 is eliminated by the motor MG1.

[0027] When it is determined in step S110 that the shift position SP is in the N position, it is determined that the inverters 41 and 42 are gate-blocked, and it is determined whether the vehicle speed V is less than or equal to the threshold value Vref (step S120). When the inverters 41 and 42 are gate-blocked during the idling operation of the engine 22, the backlash of the gear mechanism such as the planetary gear 30 cannot be eliminated by the motors MG1 and MG2. For this reason, if no countermeasure is taken, a relatively large meshing noise may occur in the gear mechanism due to the torque pulsation during the idling operation of the engine 22. When the vehicle speed V is low (including when stopped), since the road noise is relatively small, the driver is likely to feel the meshing noise that may occur in the gear mechanism. When the vehicle speed V is high, since the road noise is relatively large, the driver is less likely to feel the meshing noise. The threshold value Vref is a threshold value used to determine the degree to which the driver may feel the meshing noise that may occur in the gear mechanism due to the torque pulsation of the engine 22 when the engine 22 is idling, considering these factors. For example, about several tens of km / h is used.

[0028] When it is determined in step S120 that the vehicle speed V is less than or equal to the threshold value Vref, it is determined that there is a sufficient possibility that the driver will feel the meshing noise that may occur in the gear mechanism such as the planetary gear 30. A rotation speed Ne2 higher than the rotation speed Ne1 is set for the target rotation speed Ne* of the engine 22 (step S150), and an idling operation command and the target rotation speed Ne* of the engine 22 are transmitted to the engine ECU 24 (step S170), and this routine ends. Here, as the rotation speed Ne2, a rotation speed about several hundred rpm higher than the rotation speed Ne1 is used. 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 idling the engine 22, the frequency of the first explosion (cycle of the explosion 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 a relatively large meshing noise in the gear mechanism such as the planetary gear 30 and to suppress the driver from feeling the meshing noise.

[0029] 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 feels the gear clash sound that may occur in the gear mechanism is sufficiently low, and a rotation speed Ne3 lower than the rotation speed Ne2 is set as the target rotation speed Ne* of the engine 22 (step S160). Then, an idle operation command and the target rotation speed Ne* of the engine 22 are transmitted to the engine ECU 24 (step S170), and this routine ends. Here, as the rotation speed Ne3, for example, the same rotation speed as Ne1 or a slightly higher rotation speed than that is used. In this way, by setting the rotation speed Ne3 lower than the rotation speed Ne2 as the target rotation speed Ne* of the engine 22 and idling the engine 22, the fuel consumption of the engine 22 can be suppressed.

[0030] In the hybrid vehicle 20 of the embodiment described above, when idling the engine 22, 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, compared with 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, the engine 22 is controlled so that the engine 22 is idled at a high rotation speed. Thereby, it is possible to suppress the generation of a relatively large gear clash sound in a gear mechanism such as the planetary gear 30 and to suppress the driver from feeling the gear clash sound.

[0031] In the hybrid vehicle 20 of the embodiment, when the engine 22 is idling with the shift position SP in the N position, when the vehicle speed V is equal to or lower than the threshold value Vref, the engine 22 is idled by setting the rotational speed Ne2 to the target rotational speed Ne* of the engine 22. When the vehicle speed V is higher than the threshold value Vref, the engine 22 is idled by setting the rotational speed Ne3, which is lower than the rotational speed Ne2, to the target rotational speed Ne* of the engine 22. However, when the engine 22 is idling with the shift position SP in the N position, the engine 22 may be idled by setting the target rotational speed Ne* of the engine 22 such that it becomes lower as the vehicle speed V becomes higher. Further, when the engine 22 is idling with the shift position SP in the N position, the engine 22 may be idled by setting the rotational speed Ne2 to the target rotational speed Ne* of the engine 22 regardless of the vehicle speed V.

[0032] In the hybrid vehicle 20 of the embodiment, when the engine 22 is idling with the shift position SP other than the N position, the backlash elimination of the gear mechanism such as the planetary gear 30 is performed by the motor MG1. However, when the backlash elimination of the gear mechanism cannot be performed by the motor MG1 due to conditions such as the state of charge SOC of the battery 50, the rotational speed of the engine 22 during idling may be set to the rotational speed Ne2 or Ne3 according to the vehicle speed V, or may be set to the rotational speed Ne2 regardless of the vehicle speed V.

[0033] In the hybrid vehicle 20 of the embodiment, when the engine 22 is idling with the shift position SP other than the N position, the backlash elimination of the gear mechanism such as the planetary gear 30 is performed by the motor MG1. However, the backlash elimination of the gear mechanism may be performed by the motor MG2, or may be performed by both of the motors MG1 and MG2. When the shift position SP is in the D position or the R position, basically, the motor MG2 is driven for power running or regeneration driving based on the driving torque Td* for running based on the accelerator opening Acc and the vehicle speed V. Therefore, it is considered that the backlash elimination of the gear mechanism is being performed thereby.

[0034] In the hybrid vehicle 20 of the embodiment, the engine 22 and the motor MG1 are connected to the drive shaft 36 connected to the drive wheels 39a and 39b via the planetary gear 30, the motor MG2 is connected to the drive shaft 36, and the motors MG1 and MG2 are driven by the inverters 41 and 42. However, the present invention is not limited to this, and any configuration may be used as long as the backlash of the gear mechanism between the engine and the drive wheels can be eliminated by the motor. For example, the engine may be connected to the drive shaft connected to the drive wheels via a transmission and a clutch, and a motor may be connected to either the engine side or the drive wheel side of the transmission, and the motor may be driven by an inverter.

[0035] The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to the "engine", the motors MG1 and MG2 correspond to the "motor", and the HVECU 70, the engine ECU 24, and the motor ECU 40 correspond to the "control device".

[0036] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems is an example for specifically explaining the mode for carrying out the invention described in the column of means for solving the problems in the embodiment, and does not limit the elements of the invention described in the column of means for solving the problems. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the column of means for solving the problems.

[0037] As described above, the embodiments have been used to explain the mode for carrying out the present invention. However, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Industrial Applicability

[0038] The present invention can be used in the manufacturing industry of hybrid vehicles and the like.

Explanation of Signs

[0039] 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 Rotation position sensors, 50 Battery, 50a Voltage sensor, 50b Current sensor, 52 Battery ECU, 54 Power line, 70 HVECU, 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~D16, D21~D26 Diodes, D21 Diode, MG1, MG2 Motors, T11~T16, T21~T26 Transistors.

Claims

【Claim 1】 An engine connected to a drive wheel via a gear mechanism, A motor connected to the engine, An inverter for driving the motor, A control device that controls the inverter so that when the shift position is not in the neutral position, the backlash of the gear mechanism is eliminated by the motor, and when the shift position is in the neutral position, the inverter is gate-blocked, A hybrid vehicle comprising: When the control device idles the engine, When the shift position is not in the neutral position, the engine is controlled to idle at a first rotational speed, When the shift position is in the neutral position and the vehicle speed is below a threshold value, the engine is controlled to idle at a second rotational speed higher than the first rotational speed, When the shift position is in the neutral position and the vehicle speed is higher than the threshold value, the engine is controlled to idle at a third rotational speed lower than the second rotational speed and equal to or higher than the first rotational speed, A hybrid vehicle.

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