JP2015071367A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress stop of an engine at short time since starting.SOLUTION: An engine 22 is stopped when required power reaches less than a stopping threshold Pstop during traveling followed by operation of an engine, the stopping threshold Pstop is set so as to become smaller as a charged power amount Ech after starting as an integrated value of charged power of a battery since starting of the engine is smaller (S160-S200). Therefore, stop of the engine 22 at short time since starting is suppressed. Therefore, deterioration of fuel economy may be suppressed.

Description

  The present invention relates to a hybrid vehicle, and more particularly, to a hybrid vehicle including a traveling engine, a traveling motor, and a battery that exchanges electric power with the motor.

  Conventionally, this type of hybrid vehicle includes a traveling engine, a traveling motor, and a battery that exchanges electric power with the motor and travels while the engine is intermittently operated. There has been proposed one that sets a threshold value for stopping so as to increase as the remaining capacity of the battery increases (see, for example, Patent Document 1). In this hybrid vehicle, by setting the stop threshold value in this way, it becomes easier to run with the engine stopped when the remaining battery capacity is high, and easier to run while operating the engine when the remaining battery capacity is low. Become. As a result, when the remaining capacity of the battery is high, fuel consumption by the engine can be suppressed, and when the remaining capacity of the battery is low, the battery can be easily charged.

JP 2009-137401 A

  In the hybrid vehicle described above, when the remaining capacity of the battery is high to some extent, the threshold value for stopping is large, so that it is likely to be stopped in a short time after the engine is started. Since energy is required to start the engine, if the engine is stopped in a short time after the start, the fuel consumption tends to deteriorate.

  The main purpose of the hybrid vehicle of the present invention is to suppress the engine from being stopped in a short time after starting.

  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
A hybrid vehicle comprising a traveling engine, a traveling motor, a battery that exchanges electric power with the motor, and a control unit that controls the engine and the motor to travel while intermittently operating the engine. There,
When the forced charging request and the forced discharging request for the battery are not both made, the control means tends to increase as the charging power amount of the battery from the start of the engine becomes larger. A means for setting a threshold for use,
This is the gist.

  In the hybrid vehicle of the present invention, when neither a forced charging request nor a forced discharging request is made, the engine charging power tends to increase (decrease as the battery charging power amount increases). A stop threshold value used for stop determination is set. Accordingly, the stop threshold is relatively small immediately after the engine is started or when the amount of discharge power from the start is large, so that the engine can be prevented from being stopped. As a result, it is possible to suppress the engine from being stopped in a short time after starting, and to suppress deterioration in fuel consumption.

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 a flowchart which shows an example of the threshold value setting routine for a stop performed by HVECU70 of an Example. It is explanatory drawing which shows an example of the map for a correction amount setting. It is explanatory drawing which shows an example of the mode change of the request | requirement power Pe *, the threshold value Pstart for start, the threshold value Pstop for stop, and the rotation speed Ne of the engine 22. FIG.

  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 in the drawing, the hybrid vehicle 20 of the embodiment includes an engine 22 that outputs power using gasoline or light oil as a fuel, an engine electronic control unit (hereinafter referred to as an engine ECU) 24 that controls the drive of the engine 22, an engine, and the like. A planetary gear 30 having a carrier connected to the crankshaft 26 and a ring gear connected to a drive shaft 36 connected to drive wheels 38a and 38b via a differential gear 37, and a rotor configured as a synchronous generator motor, for example. Motor MG1 connected to the sun gear of planetary gear 30, for example, a motor MG2 configured as a synchronous generator motor and having a rotor connected to drive shaft 36, inverters 41 and 42 for driving motors MG1 and MG2, Inverters 41 and 42 not shown A motor electronic control unit (hereinafter referred to as a motor ECU) 40 that drives and controls the motors MG1 and MG2 by switching the elements, and a motor MG1, configured as, for example, a lithium ion secondary battery via inverters 41 and 42. A battery 50 that exchanges power with the MG 2, a battery electronic control unit (hereinafter referred to as a battery ECU) 52 that manages the battery 50, and a hybrid electronic control unit (hereinafter referred to as a HVECU) 70 that controls the entire vehicle. Prepare.

  Although not shown, the engine ECU 24 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 engine ECU 24 receives signals from various sensors necessary to control the operation of the engine 22, and the engine ECU 24 outputs various control signals for controlling the operation of the engine 22. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on a signal from a crank position sensor (not shown) attached to the crankshaft 26 of the engine 22.

  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 to drive and control the motors MG1 and MG2, and the motor ECU 40 outputs switching control signals to switching elements (not shown) of the inverters 41 and 42. Has been. The motor ECU 40 determines 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 sensor that detects the rotational positions of the rotors of the motors MG1, MG2. Arithmetic.

  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. The battery ECU 52 manages the battery 50 based on the integrated value of the charge / discharge current Ib of the battery 50 detected by a current sensor (not shown), and the ratio of the capacity of power that can be discharged from the battery 50 at that time to the total capacity And calculating input / output limits Win and Wout which are allowable input / output powers that may charge / discharge the battery 50 based on the calculated storage ratio SOC and the battery temperature Tb. Yes.

  Although not shown, the HVECU 70 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 HVECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator opening from the accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. Acc, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the like are input. The HVECU 70 is communicably connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

  In the hybrid vehicle 20 of the embodiment configured as described above, 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 while the operation of the engine 22 is stopped. Run.

  During travel in the HV travel mode, the HVECU 70 sets the required torque Tr * required for travel based on the accelerator opening Acc and the vehicle speed V, and sets the rotational speed Nr ( For example, the traveling power Pdrv * required for traveling is calculated by multiplying the rotational speed Nm2 of the motor MG2 and the rotational speed obtained by multiplying the vehicle speed V by a conversion factor), and the battery 50 is calculated from the calculated traveling power Pdrv *. The required power Pe * required for the vehicle is set by subtracting the charge / discharge required power Pb * (a positive value when discharging from the battery 50) based on the storage ratio SOC. The required power Pe * is output from the engine 22 and the required torque Tr * is output to the drive shaft 36 within the range of the input / output limits Win and Wout of the battery 50. Torque Te * and torque commands Tm1 * and Tm2 * for motors MG1 and MG2 are set and transmitted to engine ECU 24 and motor ECU 40. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te *, controls the intake air amount, fuel injection control, and ignition of the engine 22 so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te *. The motor ECU 40 that receives the torque commands Tm1 * and Tm2 * and the voltage command VH * performs control and the like, and switches the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. Take control. During traveling in the HV traveling mode, when the stop condition of the engine 22 is satisfied, for example, when the required power Pe * is less than the stop threshold value Pstop, the operation of the engine 22 is stopped and the traveling in the EV traveling mode is performed. Transition.

  During travel in the EV travel mode, the HVECU 70 sets a required torque Tr * based on the accelerator opening Acc and the vehicle speed V, sets a value 0 to the torque command Tm1 * of the motor MG1, and limits input / output of the battery 50. A torque command Tm2 * of the motor MG2 is set and transmitted to the motor ECU 40 so that the required torque Tr * is output to the drive shaft 36 within the range of Win and Wout. Then, the motor ECU 40 that receives the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. When traveling in the EV traveling mode, the engine 22 is turned on when the engine 22 starting condition is satisfied, for example, when the required power Pe * calculated in the same manner as in the traveling in the HV traveling mode reaches a starting threshold value Pstart or more. Start and shift to traveling in the HV traveling mode.

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the processing for setting the stop threshold value Pstop will be described. FIG. 2 is a flowchart illustrating an example of a stop threshold setting routine executed by the HVECU 70 of the embodiment. This routine is repeatedly executed every predetermined time (for example, every several msec).

  When the stop threshold setting routine is executed, the HVECU 70 first inputs the storage ratio SOC of the battery 50 and the vehicle speed V from the vehicle speed sensor 88 (step S100). Here, as the storage ratio SOC of the battery 50, a value calculated based on the integrated value of the charge / discharge current Ib of the battery 50 detected by a current sensor (not shown) is input from the battery ECU 52 by communication.

  When the data is input in this way, whether or not a forced discharge request for the battery 50 has been made (step S110), whether or not a forced charge request for the battery 50 has been made (step S120), an intermittent prohibition (continuation of operation) request for the engine 22 Is determined (step S130). Here, the forced discharge request of the battery 50 is made when the storage ratio SOC of the battery 50 is equal to or greater than a predetermined ratio Shi (for example, 70%, 75%, etc.) as the lower limit of the storage ratio range that requires forced discharge. It was supposed to be. The forced charging request of the battery 50 is made when the storage ratio SOC of the battery 50 is equal to or less than a predetermined ratio Slo (for example, 35%, 40%, etc.) as the upper limit of the storage ratio range that requires forced charging. It was. Further, the intermittent prohibition request for the engine 22 is made when the engine 22 is warmed up or when the vehicle interior is requested for heating.

  When forced discharge of the battery 50 is requested, a relatively large predetermined value P1 (for example, 7 kW, 8 kW, etc.) is set as the stop threshold value Pstop within a range smaller than the starting threshold value Pstart (for example, 12 kW, 13 kW, etc.). (Step S140), and this routine is finished. This is for facilitating running in the EV running mode (making it easy to reduce the power storage rate SOC).

  When the battery 50 is forcibly charged or when the engine 22 is intermittently prohibited, a predetermined value P2 (for example, 1 kW or 2 kW) sufficiently smaller than the predetermined value P1 is set as the stop threshold value Pstop. (Step S150), and this routine is finished. This is to facilitate traveling in the HV traveling mode (especially, when the forced charging request is made, it is easy to increase the storage ratio SOC).

  When the forced discharge request or the forced charge request for the battery 50 is not made and the intermittent prohibition request for the engine 22 is not made, the stop threshold value Pstop is set based on the vehicle speed V (step S160). In this embodiment, the stop threshold value Pstop in this case is set so as to decrease as the vehicle speed V increases within a range smaller than the predetermined value P1 and larger than the predetermined value P2. This is based on the reason that the hybrid vehicle 20 generally tends to have a large loss when the operation of the engine 22 is stopped (during traveling in the EV traveling mode) at a higher vehicle speed than at a low vehicle speed.

  Subsequently, it is determined whether or not the engine 22 is in operation (step S170), and when the engine 22 is not in operation, this routine is ended as it is.

  When the engine 22 is in operation, a post-startup charge power amount Ech (a positive value when the battery 50 is charged) is input as an integrated value of the charge power of the battery 50 from the start of the engine 22 (step S180). A correction amount ΔP for the stop threshold value Pstop is set based on the input post-startup charging electric energy Ech (step S190), and the stop threshold value Pstop is reset by adding the correction amount ΔP to the stop threshold value Pstop set in step S160. (Step S200), and this routine is finished.

  Here, as the post-startup charging electric energy Ech, a value calculated based on the charging / discharging current Ib of the battery 50 detected by a current sensor (not shown) is input from the battery ECU 52 by communication. Further, in the embodiment, the correction amount ΔP is determined in advance by storing the relationship between the post-startup charging power amount Ech and the correction amount ΔP in a ROM (not shown) as a correction amount setting map. When given, the corresponding correction amount ΔP is derived from the map and set. An example of the correction amount setting map is shown in FIG. As shown in the figure, the correction amount ΔP is set so as to increase as the post-startup charging power amount Ech increases (decreases as the charging power amount Ech decreases (increases toward the negative side)). Accordingly, the stop threshold value Pstop is set to increase as the post-startup charging power amount Ech increases (decreases as the post-startup charging power amount Ech decreases). This makes it difficult for the engine 22 to be stopped when the charge power amount Ech of the battery 50 is small during traveling in the HV mode. As a result, it is possible to suppress the engine 22 from being stopped in a short time after starting, and to suppress deterioration in fuel consumption. In the embodiment, the stop threshold value Pstop set in step S160 and the correction amount ΔP set in step S190 are set such that the reset stop threshold value Pstop is within a range smaller than the predetermined value P1 and larger than the predetermined value P2. The scope was defined.

  FIG. 4 is an explanatory diagram showing an example of how the required power Pe *, the start threshold value Pstart, the stop threshold value Pstop, and the rotational speed Ne of the engine 22 change with time. In the embodiment, a constant value is used for the starting threshold value Pstart. As shown in the figure, when the engine 22 is started at the time ts, the post-startup charging power amount Ech is small, so the stop threshold value Pstop becomes small. Thereby, it can suppress that the engine 22 stops in a short time after starting.

  According to the hybrid vehicle 20 of the embodiment described above, since the stop threshold value Pstop is set so as to decrease as the post-startup charging power Ech decreases, the engine 22 is prevented from being stopped in a short time from the start. be able to. As a result, deterioration of fuel consumption can be suppressed.

  In the embodiment, the hybrid vehicle 20 is configured such that the engine 22, the motor MG1, and the drive shaft 36 are connected to the carrier, the sun gear, and the ring gear of the planetary gear 30, and the motor MG2 is connected to the drive shaft 36. In addition, since a configuration including a traveling motor and a battery that exchanges electric power with the motor is sufficient, a configuration such as a one-motor hybrid vehicle may be used.

  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 motor MG2 corresponds to the “motor”, the battery 50 corresponds to the “battery”, and the HVECU 70 and the engine 22 that execute the stop threshold setting routine of FIG. The engine ECU 24 that controls the motor ECU 40 and the motor ECU 40 that controls the motor MG2 correspond to “control means”.

  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 can be used in the manufacturing industry of hybrid vehicles.

  20 hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 40 motor electronic control unit (motor ECU), 41, 42 Inverter, 50 Battery, 52 Electronic control unit for battery (battery ECU), 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)

A hybrid vehicle comprising a traveling engine, a traveling motor, a battery that exchanges electric power with the motor, and a control unit that controls the engine and the motor to travel while intermittently operating the engine. There,
When the forced charging request and the forced discharging request for the battery are not both made, the control means tends to increase as the charging power amount of the battery from the start of the engine becomes larger. A means for setting a threshold for use,
A hybrid vehicle characterized by that.

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