JP2019182209A - Hybrid vehicle - Google Patents

Abstract

To provide a hybrid vehicle capable of suppressing occurrence of shock in start up of an engine and suppressing reduction of energy efficiency.SOLUTION: A hybrid vehicle is configured so that, in electrically driven travel for traveling in a state of stopping operation of an engine, when a request torque required for travel is equal to or greater than a start-up threshold obtained by subtracting a margin from a shock occurrence threshold, a first motor performs cranking of an engine for start up of the engine, and the engine and the first and second motors are controlled to make the vehicle travel at a torque which is changed at a change rate to the request torque. Then, in electrically driven travel, the change rate in cranking of the engine is set so that, when the change rate is small, the change rate becomes smaller compared with when the change rate is large, and a margin is reduced when the change rate in cranking is small, compared with when the change rate in cranking is large. Therefore, it is possible to achieve suppression of occurrence of shock when starting up the engine, and suppression of reduction of energy efficiency.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a hybrid vehicle, and more particularly, to a hybrid vehicle including an engine, a first motor, a planetary gear, and a second motor.

  Conventionally, as this type of hybrid vehicle, a vehicle including an engine, a first motor, a planetary gear, and a second motor has been proposed (see, for example, Patent Document 1). In the planetary gear, three rotating elements are connected to the output shaft of the engine, the rotating shaft of the first motor, and the axle. The second motor inputs and outputs power to the drive shaft. In this vehicle, when the required torque required for traveling reaches or exceeds the threshold for starting, the engine is cranked and started by the first motor. During engine cranking, the required torque change rate is reduced compared to when the engine is not cranking, thereby reducing the amount of increase in the required torque during engine cranking. The starting threshold value can be increased within a range in which the required torque does not exceed the shock occurrence threshold at which shock occurs during cranking. As a result, the engine is stopped as much as possible to improve energy efficiency.

JP 2014-19354 A

  In the above-described hybrid vehicle, when the change rate of the engine before cranking starts is large, the change rate during the cranking starts small, such as when the change rate during engine cranking is small even though the change rate of cranking is small, the user May give a sense of incongruity. Increasing the rate of change during engine cranking can also be considered as a method for suppressing such discomfort to the user. However, when the change rate is increased, the amount of increase in the required torque during cranking increases. Therefore, in order to prevent the required torque from exceeding the shock occurrence threshold at which shock occurs during engine cranking, it is necessary to lower the starting threshold. If the threshold for starting is lowered, the time for which the engine is stopped is shortened, and the energy efficiency is lowered.

  The main purpose of the hybrid vehicle of the present invention is to achieve both suppression of the occurrence of shock when starting the engine and suppression of reduction in energy efficiency.

  The hybrid vehicle of the present invention employs the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
Engine,
A first motor;
A planetary gear having three rotating elements connected to an output shaft of the engine, a rotating shaft of the first motor, and a drive shaft connected to an axle;
A second motor that inputs and outputs power to the drive shaft;
When the required torque required for traveling is greater than or equal to the starting threshold value obtained by subtracting the margin from the shock occurrence threshold value during electric traveling in which the engine operation is stopped, the engine is cranked by the first motor. And a control device that controls the engine and the first and second motors so as to start and run at a torque that changes at a change rate toward the required torque;
A hybrid vehicle comprising:
The controller is
During the electric travel, when the change rate is small, the change rate during cranking of the engine is set to be smaller than when it is large,
When the change rate during the cranking is small, the margin is made smaller than when it is large.
This is the gist.

  In the hybrid vehicle of the present invention, when the required torque required for traveling is greater than or equal to the starting threshold value obtained by subtracting the margin from the shock occurrence threshold value during the electric traveling that stops the engine operation, the first motor The engine and the first and second motors are controlled so as to crank and start the engine and to run at a torque that changes at a change rate toward the required torque. Then, during the electric running, the change rate during cranking of the engine is set so as to be smaller than when it is large when the change rate is small. That is, the change rate of the required torque during cranking of the engine is set so as to become smaller as the change rate of the required torque during electric traveling becomes smaller. Thereby, it can suppress that the change rate of a request | requirement torque changes before and after cranking of an engine, and can suppress generation | occurrence | production of a shock. When the change rate during cranking is small, the margin is made smaller than when the change rate is large. That is, the margin is made smaller as the change rate of the required torque during cranking is smaller, and the threshold for starting becomes higher as the change rate of the required torque during cranking is smaller and the increase amount of the required torque during cranking is smaller. . Thereby, since electric driving | running | working continues for a longer time, the fall of energy efficiency can be suppressed. As a result, it is possible to achieve both suppression of occurrence of shock when starting the engine and suppression of reduction in energy efficiency.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. It is explanatory drawing for demonstrating an example of the relationship between rate value Rtv and rate value Rtcr. It is explanatory drawing for demonstrating an example of the relationship between rate value Rtcr and the margin M. FIG. It is explanatory drawing for demonstrating an example of the time change of request | requirement torque Td *.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown, the hybrid vehicle 20 of the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 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 or light oil as a fuel. The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as “engine ECU”) 24. The engine 22 is suspended from the vehicle body 12 by an engine mount 14. The engine mount 14 has an elastic body such as rubber inside, and can absorb vibration.

  Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and includes, in addition to the CPU, a ROM that stores a processing program, a RAM that temporarily stores data, an input / output port, and a communication port. . The engine ECU 24 receives signals from various sensors necessary for controlling the operation of the engine 22, for example, a crank angle θcr from the crank position sensor 23 that detects the rotational position of the crankshaft 26 of the engine 22 from an input port. Has been. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. The engine ECU 24 is connected to the HVECU 70 via a 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 23.

  The planetary gear 30 is configured as a single pinion type planetary gear mechanism. The sun gear of planetary gear 30 is connected to the rotor of motor MG1. The ring gear of the planetary gear 30 is connected to a drive shaft 36 that is coupled to the drive wheels 39a and 39b via a differential gear 38. A crankshaft 26 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28.

  The motor MG1 is configured as, for example, a synchronous generator motor, and the rotor is connected to the sun gear of the planetary gear 30 as described above. The motor MG2 is configured as, for example, a synchronous generator motor, and a rotor is connected to the drive shaft 36. Inverters 41 and 42 are connected to motors MG <b> 1 and MG <b> 2 and to battery 50 via power line 54. The motors MG1 and MG2 are driven to rotate by switching control of a plurality of switching elements (not shown) of the inverters 41 and 42 by a motor electronic control unit (hereinafter referred to as “motor ECU”) 40.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The motor ECU 40 receives signals from various sensors necessary for driving and controlling the motors MG1 and MG2, for example, rotational positions θm1 from rotational position detection sensors 43 and 44 that detect rotational positions of the rotors of the motors MG1 and MG2. , Θm2, etc. are input via the input port. From the motor ECU 40, switching control signals to a plurality of switching elements (not shown) of the inverters 41 and 42 are output via an output port. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 calculates the rotational 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 detection sensors 43, 44.

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

  Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input port. Examples of the signal input to the battery ECU 52 include the voltage Vb of the battery 50 from the voltage sensor 51 a installed between the terminals of the battery 50 and the current of the battery 50 from the current sensor 51 b attached to the output terminal of the battery 50. The temperature Tb of the battery 50 from the temperature sensor 51c attached to Ib and the battery 50 can be mentioned. The battery ECU 52 is connected to the HVECU 70 via a communication port. Battery ECU 52 calculates storage rate SOC based on the integrated value of current Ib of battery 50 from current sensor 51b. The storage ratio SOC is a ratio of the capacity 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 configured as a microprocessor centered on a CPU, and includes a ROM that stores a processing program, a RAM that temporarily stores data, an input / output port, and a communication port in addition to the CPU. Signals from various sensors are input to the HVECU 70 via input ports. Examples of the signal input to the HVECU 70 include an ignition signal from the ignition switch 80 and a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81. Further, 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 sensor 88 The vehicle speed V can also be mentioned. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port.

  The hybrid vehicle 20 of the embodiment configured in this way is in a hybrid travel mode (HV travel mode) that travels with the operation of the engine 22 or an electric travel mode (EV travel mode) that travels without the operation of the engine 22. Run.

  In the HV travel mode, the HVECU 70 sets the temporary required torque Tdtmp as a temporary value of the required torque Td * required for travel (required for the drive shaft 36) based on the accelerator opening Acc and the vehicle speed V. Next, the rate value Rthv of the required torque Td * in the HV traveling mode is set so that when the temporary required torque Tdtmp is large, it becomes larger than when it is small, that is, as the temporary required torque Tdtmp increases. To do. The rate value Rthv is set based on the control responsiveness of the engine 22 and the motor MG2. Then, the required torque Td * is set so as to change at the rate value Rthv from the already set required torque Td * (previous Td *) toward the temporary required torque Tdtmp. Then, the required power Pd * required for traveling is calculated by multiplying the set required torque Td * by the rotational speed Nd of the drive shaft 36 (the rotational speed Nm2 of the motor MG2). Subsequently, the vehicle is required (required for the engine 22) by subtracting the charge / discharge required power Pb * (positive value when discharging from the battery 50) based on the storage ratio SOC of the battery 50 from the required power Pd *. The required power Pe * is set, the required power Pe * is output from the engine 22, and the required torque Td * is output to the drive shaft 36. Set torque commands Tm1 * and Tm2 * for MG1 and MG2. Then, the target rotational speed Ne * and target torque Te * of the engine 22 are transmitted to the engine ECU 24, and torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are transmitted to the motor ECU 40. When the engine ECU 24 receives the target rotational speed Ne * and the target torque Te * of the engine 22, the engine ECU 24 controls the operation of the engine 22 (intake air) so that the engine 22 is operated based on the target rotational speed Ne * and the target torque Te *. Volume control, fuel injection control, ignition control, etc.). When motor ECU 40 receives torque commands Tm1 * and Tm2 * of motors MG1 and MG2, switching control of a plurality of switching elements of inverters 41 and 42 is performed such that motors MG1 and MG2 are driven by torque commands Tm1 * and Tm2 *. To do.

  In the EV travel mode, the HVECU 70 sets the temporary required torque Tdtmp based on the accelerator opening Acc and the vehicle speed V, and uses the EV travel mode in the same manner as the rate value Rhv in the HV travel mode based on the temporary required torque Tdtmp. The rate value Rtv at is set. The rate value Rtv is set based on the control responsiveness of the motor MG2. Then, the required torque Td * is set so as to change from the previous Td * toward the temporary required torque Tdtmp at the rate value Rtv. Then, a value 0 is set for the torque command Tm1 * of the motor MG1, and a torque command Tm2 * for the motor MG2 is set so that the required torque Td * is output to the drive shaft 36, and a torque command Tm1 * for the motors MG1 and MG2 is set. , Tm2 * is transmitted to the motor ECU 40. The control of the inverters 41 and 42 by the motor ECU 40 has been described above.

  During the travel in the EV travel mode, when the temporary required torque Tdtmp becomes equal to or greater than the starting threshold value Tst, the EV travel mode is shifted to the HV travel mode. When shifting from the EV travel mode to the HV travel mode, the engine 22 is started by cooperative control of the HVECU 70, the engine ECU 24, and the motor ECU 40. In the starting process of the engine 22, cranking torque Tcr (positive torque) for cranking the engine 22 is output from the motor MG1, and the engine 22 is cranked. At this time, the motor MG2 outputs the sum of the required torque Td * and the torque for canceling the torque output from the motor MG1 and output (transmitted) to the drive shaft 36 via the planetary gear 30. The required torque Td * is set as a temporary required torque Tdtmp based on the accelerator opening degree Acc and the vehicle speed V, and a rate value Rtcr that is a rate of change of the required torque Td * in the starting process of the engine 22 is set. The required torque Td * is set so as to change at the rate value Rtcr toward Tdtmp. When the rotational speed Ne of the engine 22 is equal to or greater than the operation start threshold Nst (for example, 800 rpm, 900 rpm, 1000 rpm, etc.), operation control (fuel injection control, ignition control, etc.) of the engine 22 is started. Then, when the engine 22 completes explosion, traveling in the HV traveling mode is started. The setting of the starting threshold value Tst and the rate value Rtcr will be described later.

   When shifting from the HV traveling mode to the EV traveling mode, a rotation stop process for stopping the rotation of the engine 22 is executed by cooperative control of the HVECU 70, the engine ECU 24, and the motor ECU 40 to start traveling in the EV traveling mode. To do. Since the rotation stop process of the engine 22 does not form the core of the present invention, the description thereof is omitted.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when setting the rate value Rtcr and the starting threshold value Tst will be described. First, setting of the rate value Rtcr will be described, and then setting of the starting threshold value Tst will be described.

  The rate value Rtcr is set by using the rate value Rtv in the EV traveling mode during traveling in the EV traveling mode. FIG. 2 is an explanatory diagram for explaining an example of the relationship between the rate value Rtv and the rate value Rtcr. As shown in the figure, rate value Rtcr is set to increase as rate value Rtv increases toward upper limit value Rcrmax when rate value Rtv is less than predetermined value Rref. That is, when the rate value Rtv is less than the predetermined value Rref, the rate value Rtcr is set to be smaller when the rate value Rtv is small than when it is large. The rate value Rtcr is set to be the upper limit value Rcrmax regardless of the rate value Rtv when the rate value Rtv is equal to or greater than the predetermined value Rref. By such processing, when the engine 22 is started with the transition from the EV traveling mode to the HV traveling mode, the rate value Rtv in the EV traveling mode immediately before starting the engine 22 is set. The required torque Td * is set so as to change toward the temporary required torque Tdtmp at the rate value Rtcr. When the rate value Rtcr increases, the control of the motor MG2 may not follow the change in the required torque Td *, or the vehicle may accelerate excessively and the user may feel uncomfortable. The upper limit value Rcrmax is set in consideration of such control responsiveness of the motor MG2 and the user's uncomfortable feeling.

  The starting threshold value Tst is set as a torque obtained by subtracting the margin M from the shock occurrence threshold value Tth. The shock occurrence threshold Tth is a torque at which a shock is generated when the engine mount 14 hits the bottom of the engine 22 (when the engine mount 14 is in contact with the bottom). The margin M is set using the rate value Rtcr. FIG. 3 is an explanatory diagram for explaining an example of the relationship between the rate value Rtcr and the margin M. As illustrated, when the rate value Rtcr is less than the predetermined value Rcrref, the margin M is set to increase as the rate value Rtcr increases toward the upper limit value Mmax. That is, when the rate value Rtcr is less than the predetermined value Rcrref, the margin M is set to be smaller when the rate value Rtcr is small than when it is large. The margin M is set to be the upper limit value Mmax regardless of the rate value Rtcr when the rate value Rtcr is equal to or greater than the predetermined value Rcrref. If the engine 22 is started with the engine mount 14 in contact with the bottom, vibrations at the time of start-up may be easily transmitted to the vehicle body 12, and a shock at the time of start-up may increase. In the embodiment, by setting the starting threshold value Tst as a torque obtained by subtracting the margin M from the shock occurrence threshold value Tth, the starting of the engine 22 with the engine mount 14 in contact with the bottom is suppressed. Can suppress the shock. When the margin M increases, the starting threshold value Tst becomes a small value, and the engine 22 is started early from the EV traveling mode, resulting in a reduction in energy efficiency. The upper limit value Mmax is determined by experiment, analysis, or the like as a value that limits the margin M so that the energy efficiency does not decrease excessively.

  FIG. 4 is an explanatory diagram for explaining an example of a temporal change in the required torque Td *. In the figure, the solid line shows an example of a change over time of the required torque Td * when the rate value Rtv in the EV travel mode is a predetermined value R1 smaller than the predetermined value Rref in FIG. “Tst1” is the value of the start threshold Tst when the rate value Rtv in the EV travel mode is the predetermined value R1. The broken line shows an example of the time change of the required torque Td * when the rate value Rtv in the EV travel mode is a predetermined value R2 smaller than the predetermined value R1. “Tst2” is a value of the starting threshold value Tst when the rate value Rtv in the EV traveling mode is the predetermined value R2. When the rate value Rtv in the EV traveling mode is the predetermined value R1, the start process of the engine 22 is started at the timing (time t1) when the required torque Td * becomes the start threshold value Tst (= Tst1), and the engine by the motor MG1 22 cranking starts. Thereafter, the required torque Td * increases toward the temporary required torque Trtmp at the rate value Rtcr. When the rate value Rtv in the EV traveling mode is the predetermined value R2, the engine 22 is started at the timing (time t2) when the required torque Td * becomes the starting threshold value Tst (= Tst2). 22 cranking starts. Thereafter, the required torque Td * increases toward the temporary required torque Trtmp at the rate value Rtcr. As shown in the figure, rate value Rtcr is smaller when rate value Rtv in EV traveling mode is small (broken line) than when it is large (solid line). As a result, the rate value of the required torque Td * is prevented from changing greatly before and after the timing (time t1, t2) when the required torque Td * becomes the starting threshold value Tst, that is, before and after the engine 22 is cranked. The Therefore, it is possible to suppress the occurrence of shock due to a large change in the rate value of the required torque Td * before and after the engine 22 is cranked. Further, when the rate value Rtcr during cranking is small, the margin M is made smaller than when the rate value Rtcr is large, that is, the rate M Rtr is smaller as the rate value Rtcr is smaller. The starting threshold value Tst is increased as the increase amount of the torque Td * is smaller. Thereby, since driving | running | working in EV driving mode can be continued for a long time, the fall of energy efficiency can be suppressed. Therefore, it is possible to achieve both suppression of occurrence of shock when starting the engine 22 and suppression of reduction in energy efficiency.

  According to the hybrid vehicle 20 of the embodiment described above, during traveling in the EV traveling mode, when the rate value Rtv during EV traveling is small, the rate during cranking of the engine 22 is smaller than when it is large. By setting the value Rtcr and making the margin M smaller when the rate value Rtcr during cranking is small than when it is large, the occurrence of shock when starting the engine 22 and the reduction in energy efficiency are reduced. Can be achieved.

  In the hybrid vehicle 20 of the embodiment, as shown in FIG. 2, the rate value Rtcr is set to be smaller when the rate value Rtv is less than the predetermined value Rref, compared to when it is large when the rate value Rtv is small. When the rate value Rtv is equal to or greater than the predetermined value Rref, the upper limit value Rcrmax is set regardless of the rate value Rtv. However, the rate value Rtcr may be set to be smaller when the rate value Rtv is smaller than when it is smaller, regardless of whether or not the rate value Rtv is less than the predetermined value Rref.

  In the hybrid vehicle 20 of the embodiment, as shown in FIG. 3, when the rate value Rtcr is less than the predetermined value Rcrref, the margin M is set to be smaller than when the rate value Rtcr is small. When the rate value Rtcr is equal to or greater than the predetermined value Rcrref, the upper limit value Mmax is set regardless of the rate value Rtcr. However, the margin M may be set to be smaller when the rate value Rtcr is smaller than when the rate value Rtcr is greater than or equal to the predetermined value Rcrref.

  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 an “engine”, the motor MG1 corresponds to a “first motor”, the planetary gear 30 corresponds to a “planetary gear”, the motor MG2 corresponds to a “second motor”, and the engine ECU 24 The motor ECU 40 and the HVECU 70 correspond to a “control device”.

  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 problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention is applicable to the hybrid vehicle manufacturing industry and the like.

  12 vehicle body, 14 engine mount, 20 hybrid vehicle, 22 engine, 23 crank position sensor, 24 engine electronic control unit (engine ECU), 26 crankshaft, 28 damper, 30 planetary gear, 36 drive shaft, 38 differential gear, 39a, 39b Drive wheel, 40 Motor electronic control unit (motor ECU), 41, 42 Inverter, 43, 44 Rotation position detection sensor, 46 Capacitor, 50 Battery, 51a Voltage sensor, 51b Current sensor, 51c Temperature sensor, 52 Battery electronics Control unit (battery ECU), 54 electric power line, 70 electronic control unit for hybrid (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, 88 vehicle speed sensor, MG1, MG2 motor.

Claims (1)

Engine,
A first motor;
A planetary gear having three rotating elements connected to an output shaft of the engine, a rotating shaft of the first motor, and a drive shaft connected to an axle;
A second motor that inputs and outputs power to the drive shaft;
When the required torque required for traveling is greater than or equal to the starting threshold value obtained by subtracting the margin from the shock occurrence threshold value during electric traveling in which the engine operation is stopped, the engine is cranked by the first motor. And a control device that controls the engine and the first and second motors so as to start and run at a torque that changes at a change rate toward the required torque;
A hybrid vehicle comprising:
The controller is
During the electric travel, when the change rate is small, the change rate during cranking of the engine is set to be smaller than when it is large,
When the change rate during the cranking is small, the margin is made smaller than when it is large.
Hybrid vehicle.

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