JP2013107432A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle capable of preventing a sense of incongruity given to a driver when riding over a level difference.SOLUTION: A hybrid vehicle 100 includes: an engine 1 and a motor MG2 for driving a driving wheel 8; and an HVECU 11 of controlling the engine 1 and the motor MG2. The HVECU 11 is configured to inhibit starting of the engine 1 when riding over a level difference during an intermittent operation of the engine 1.

Description

  The present invention relates to a hybrid vehicle including an engine and an electric motor.

  Conventionally, a hybrid vehicle including an engine and a motor (electric motor) for driving drive wheels is known (see, for example, Patent Document 1).

  In such a hybrid vehicle, the engine is intermittently operated based on the traveling state, the state of the battery, and the like. For example, such a hybrid vehicle stops the operation of the engine and travels only by the power of the motor when starting when the battery is not required to be charged.

  Moreover, the hybrid vehicle of patent document 1 is comprised so that a driving force may be increased when a level | step difference of a road surface is detected, and the level difference is overcome. As a result, it is not necessary to extremely increase the amount of depression of the accelerator pedal when climbing over a step, and thus driving operability can be improved.

JP 2007-83993 A

  Here, in the hybrid vehicle in which the engine is intermittently operated, there is a problem in that when the engine is started when the vehicle is stepped over, the driver (driver) may feel uncomfortable. In particular, when a hybrid vehicle gets over a level difference, the accelerator pedal is depressed by the driver, the required value of the driving force output to the driving wheel increases, and the engine is easily started, so there is a high possibility that the driver will feel uncomfortable. .

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a hybrid vehicle capable of suppressing the driver from feeling uncomfortable when getting over a step. is there.

  The hybrid vehicle according to the present invention includes an engine and an electric motor for driving the drive wheels, and a control device for controlling the engine and the electric motor. The control device is configured to be able to intermittently operate the engine, and is configured to prohibit starting of the engine when overcoming a road step during intermittent operation of the engine.

  By configuring in this way, it is possible to suppress the start of the engine from overlapping at the timing of stepping over the step, and thus it is possible to suppress the driver from feeling uncomfortable.

  In the hybrid vehicle, the control device determines that there is a step when the vehicle speed corresponding to the driving force output to the driving wheel is not obtained, and the engine is set for a preset period when it is determined that the step exists. May be configured to prohibit the starting of the.

  If comprised in this way, when it determines with a level | step difference existing, starting of an engine can be prohibited when getting over the level | step difference.

  In this case, a vehicle speed sensor for detecting the vehicle speed and an accelerator pedal position sensor for detecting the depression amount of the accelerator pedal are provided, and the control device is based on the detection results of the vehicle speed sensor and the accelerator pedal position sensor. It may be configured to determine whether or not there is a step.

  If comprised in this way, it can be determined easily whether a level | step difference exists.

  According to the hybrid vehicle of the present invention, it is possible to suppress the driver from feeling uncomfortable when getting over the step.

1 is a diagram illustrating an overall configuration of a hybrid vehicle according to an embodiment of the present invention. It is the block diagram which showed HVECU of the hybrid vehicle of FIG. It is the block diagram which showed the HV battery and PCU of the hybrid vehicle of FIG. FIG. 2 is a flowchart for illustrating control when a hybrid vehicle of FIG. It is a flowchart for demonstrating the level | step difference determination process of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

-Mechanical configuration-
First, a mechanical configuration (drive mechanism) of a hybrid vehicle 100 according to an embodiment of the present invention will be described with reference to FIG.

  Hybrid vehicle 100 is, for example, an FF (front engine / front drive) system, and drives left and right front wheels (drive wheels) 8. As shown in FIG. 1, the hybrid vehicle 100 includes an engine (internal combustion engine) 1, a generator MG 1, a motor MG 2, a power split mechanism 2, a reduction mechanism 3, a reduction gear 4, a differential device 5, And a drive shaft 6.

  The engine 1 is a known power device that outputs power by burning fuel such as a gasoline engine or a diesel engine. The engine 1 is configured to be able to control operation states such as a throttle opening (intake air amount) of a throttle valve provided in an intake passage, fuel injection amount, ignition timing, and the like.

  The output of the engine 1 is transmitted to the input shaft 2a of the power split mechanism 2 via the crankshaft 1a and the damper 7. The damper 7 is a coil spring type transaxle damper, for example, and absorbs torque fluctuations of the engine 1.

  Generator MG1 mainly functions as a generator, and also functions as a motor depending on the situation. Generator MG1 is, for example, an AC synchronous generator, and includes a rotor MG1R made of a permanent magnet rotatably supported with respect to input shaft 2a, and a stator MG1S around which three-phase windings are wound.

  The motor MG2 mainly functions as an electric motor, and also functions as a generator depending on the situation. Motor MG2 is an AC synchronous motor, for example, and has a rotor MG2R made of a permanent magnet and a stator MG2S around which a three-phase winding is wound. The motor MG2 is an example of the “motor” in the present invention.

  The power split mechanism 2 is a mechanism that divides the output of the engine 1 into power that drives the left and right front wheels 8 and power that drives the generator MG1 for power generation, and is, for example, a planetary gear mechanism.

  Specifically, the power split mechanism 2 includes an external gear sun gear 2S that rotates at the center of a plurality of gear elements, and an external gear pinion gear that revolves around the sun gear 2S while rotating around it (meshing). 2P, a ring gear 2R of an internal gear formed in a hollow annular shape so as to mesh with the pinion gear 2P, and a planetary carrier 2C that supports the pinion gear 2P and rotates through the revolution of the pinion gear 2P.

  The planetary carrier 2C is connected to the input shaft 2a on the engine 1 side so as to rotate together. Sun gear 2S is connected to rotor MG1R of generator MG1 so as to rotate together.

  By providing this power split mechanism 2, the power output from the engine 1 is divided into power transmitted from the planetary carrier 2C to the sun gear 2S and power transmitted to the ring gear 2R.

  Of these divided powers, the power transmitted to the sun gear 2S is transmitted to the rotor MG1R of the generator MG1, and the rotor MG1R is driven by the power to generate power in the generator MG1. When engine 1 is started, generator 1 is driven by electric power supplied from HV battery 13, and engine 1 is cranked. That is, generator MG1 also functions as a starter motor when engine 1 is started.

  On the other hand, the power transmitted from the engine 1 to the ring gear 2R is integrated with the power output from the motor MG2, and is transmitted from the ring gear 2R to the front wheels 8 via the speed reducer 4, the differential device 5 and the drive shaft 6. The front wheels 8 are driven by the transmitted power.

  The reduction mechanism 3 is a mechanism that decelerates the rotation of the motor MG2 and amplifies the drive torque, and is a planetary gear mechanism, for example.

  Specifically, the reduction mechanism 3 is hollow so as to mesh with the sun gear 3S of an external gear that rotates at the center of a plurality of gear elements, the pinion gear 3P of an external gear that rotates while circumscribing the sun gear 3S, and the pinion gear 3P. A ring gear 3R of an internal gear formed in an annular shape.

  The ring gear 3R of the reduction mechanism 3 and the ring gear 2R of the power split mechanism 2 are integrated with each other. The sun gear 3S is connected to the rotor MG2R of the motor MG2 so as to rotate together.

  By providing the reduction mechanism 3, when the motor MG2 is driven, the output (power) of the motor MG2 is integrated with the power transmitted from the engine 1 to the ring gear 2R of the power split mechanism 2. Thereby, the output of the engine 1 can be assisted (assist), and the driving force of the front wheels 8 can be increased. Note that, during low-speed light load traveling or the like, traveling (EV traveling) can be performed only with the power of the motor MG2 while the engine 1 is stopped. Further, during regenerative braking, the motor MG2 can generate electric power by converting kinetic energy into electric energy.

-Electrical configuration-
Next, the electrical configuration (electric system) of the hybrid vehicle 100 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the hybrid vehicle 100 includes an HVECU 11, an engine ECU 12, an HV battery 13, and a PCU (power control unit) 14.

[HVECU]
The HVECU 11 is configured to centrally control the hybrid vehicle 100. For example, the HVECU 11 controls the traveling of the hybrid vehicle 100 by executing a hybrid system (vehicle system). The HVECU 11 is an example of the “control device” in the present invention.

  Here, the hybrid system refers to driving of the hybrid vehicle 100 by executing various controls including operation control of the engine 1, drive control of the generator MG1 and motor MG2, and cooperative control of the engine 1, generator MG1 and motor MG2. It is a system to control.

  As shown in FIG. 2, the HVECU 11 includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, a backup RAM 114, an input / output interface 115, and a communication interface. 116.

  The CPU 111 executes arithmetic processing based on various control programs and maps stored in the ROM 112. The ROM 112 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The RAM 113 is a memory that temporarily stores calculation results by the CPU 111 and detection results of the sensors. The backup RAM 114 is a non-volatile memory that stores data to be saved when turning off the ignition.

  The input / output interface 115 has a function of inputting a detection result of each sensor and outputting a control signal to each unit. For example, a vehicle speed sensor 21, an accelerator pedal position sensor 22, a brake pedal position sensor 23, a selector lever position sensor 24, a P position switch 25, and a power switch 26 are connected to the input / output interface 115.

  The vehicle speed sensor 21 is a sensor for detecting the vehicle speed of the hybrid vehicle 100. The accelerator pedal position sensor 22 is a sensor for detecting the depression amount of the accelerator pedal 22a, and the brake pedal position sensor 23 is a sensor for detecting the depression amount of the brake pedal 23a. The power switch 26 is a switch for starting and stopping the hybrid system. The selector lever position sensor 24 and the P position switch 25 will be described later.

  The communication interface 116 is provided to communicate with each ECU (for example, the engine ECU 12). For example, the yaw rate sensor 27 and the linear G sensor 28 are connected to the communication interface 116. The yaw rate sensor 27 is a sensor for detecting a rotational angular velocity centered on the vertical direction, and the linear G sensor 28 is a sensor for detecting acceleration (deceleration) in the horizontal direction.

[Engine ECU]
The engine ECU 12 (see FIG. 1) includes a CPU, a ROM, a RAM, a backup RAM, an input / output interface, a communication interface, and the like. The engine ECU 12 executes various controls of the engine 1 including intake air amount control, fuel injection amount control, ignition timing control, and the like in response to an output request from the HVECU 11.

[HV battery]
As shown in FIG. 3, the HV battery 13 includes a battery module 131 that is a high-voltage power supply for traveling, a battery monitoring unit 132 that monitors the battery module 131, and a system main relay 133.

  The battery module 131 is configured to supply electric power for driving the generator MG1 and the motor MG2, and to store electric power generated by the generator MG1 and the motor MG2. The battery module 131 is a chargeable / dischargeable nickel metal hydride battery or a lithium ion battery, for example.

  The battery monitoring unit 132 is connected to a current sensor that detects the charge / discharge current of the battery module 131, a voltage sensor that detects the voltage of the battery module 131, and a temperature sensor that detects the temperature (battery temperature) of the battery module 131. ing. Then, the battery monitoring unit 132 transmits information (charge / discharge current, voltage, and battery temperature) regarding the battery module 131 to the HVECU 11. Thereby, for example, the HVECU 11 calculates the SOC (State of Charge) of the battery module 131 based on the integrated value of the charge / discharge current, and sets the input limit Win and the output limit Wout based on the SOC and the battery temperature. Calculate.

  The system main relay 133 is provided between the battery module 131 and the PCU 14 in order to connect or disconnect the battery module 131 and the PCU 14. The system main relay 133 is switched on / off based on a control signal from the HVECU 11.

  When the system main relay 133 is in the on state, the power of the battery module 131 can be supplied to the PCU 14 and the battery module 131 can be charged with the power supplied from the PCU 14. Further, when the system main relay 133 is off, the battery module 131 can be electrically separated from the PCU 14.

[PCU (Power Control Unit)]
PCU 14 includes a step-up / down converter 141, inverters 142 and 143, and MGECU 144.

  The step-up / down converter 141 is provided to step up the DC voltage of the HV battery 13 and supply it to the inverters 142 and 143. Further, the step-up / down converter 141 steps down the voltage generated by the generator MG1 and converted into direct current by the inverter 142 and supplies the voltage to the HV battery 13, and is also generated by the motor MG2 and converted into direct current by the inverter 143. Has a function of stepping down the voltage and supplying it to the HV battery 13.

  Specifically, the buck-boost converter 141 is a chopper-type buck-boost converter, for example, and includes a reactor, an IGBT (Insulated Gate Bipolar Transistor), and a diode. The step-up / down converter 141 is configured to increase or decrease the voltage by controlling the on / off state of the IGBT according to the drive signal supplied from the MGECU 144.

  Inverters 142 and 143 are, for example, a three-phase bridge circuit having an IGBT and a diode, and regenerative control or power running control is performed by controlling the on / off state of the IGBT by a drive signal supplied from MGECU 144.

  Specifically, the inverter 142 converts the alternating current generated by the generator MG1 by the power of the engine 1 into a direct current and outputs the direct current to the step-up / down converter 141 (regenerative control) and is supplied from the step-up / down converter 141. The generator MG1 is driven by converting a direct current into an alternating current (power running control).

  The inverter 143 converts the direct current supplied from the step-up / down converter 141 into an alternating current to drive the motor MG2 (powering control) and converts the alternating current generated by the motor MG2 during regenerative braking into a direct current. And output to the step-up / down converter 141 (regenerative control).

  The MGECU 144 includes a CPU, ROM, RAM, backup RAM, input / output interface, communication interface, and the like. The MGECU 144 receives the output request transmitted from the HVECU 11, generates a drive signal for the step-up / down converter 141 and the inverters 142 and 143 based on the output request, etc., and outputs the drive signal to the step-up / down converter 141, the inverter 142 and To 143.

-Shift position-
Next, the shift position of the hybrid vehicle 100 according to the present embodiment will be described.

  The hybrid vehicle 100 includes a drive position (D position) for forward travel, a brake position (B position) for forward travel with a large braking force (engine brake) when the accelerator is off, a reverse position (R position) for reverse travel, The shift position can be set to either a neutral position (N position) or a parking position (P position) for parking. In the hybrid vehicle 100, the shift position is managed by the HVECU 11.

  Specifically, the HVECU 11 sets the shift position to the D position, the B position, the R position, or the N position based on a signal output from the selector lever position sensor 24 according to the operation of the selector lever (not shown) by the driver. Set to.

  Further, the HVECU 11 sets the shift position to the P position based on a signal output from the P position switch 25 in accordance with the operation of the driver. When the P position is set, the movement of the hybrid vehicle 100 is restricted by operating a parking lock mechanism (not shown).

-Running condition-
Next, an example of the traveling state of the hybrid vehicle 100 according to the present embodiment will be described.

  For example, hybrid vehicle 100 stops the operation of engine 1 at the time of start-up and at a low vehicle speed at a light load, and travels (EV travel) by controlling power running of motor MG2.

  In addition, hybrid vehicle 100 travels using engine 1 as a main power source during steady travel, for example, and performs regenerative control of generator MG1, and auxiliary power running control of motor MG2 with electric energy obtained by the regenerative control. To do.

  Hybrid vehicle 100 travels while driving engine 1 while powering motor MG2 with electric energy obtained by regenerative control of generator MG1 and electric energy of HV battery 13 during acceleration or the like.

  In addition, the hybrid vehicle 100 regeneratively controls the motor MG2 when decelerating (when the accelerator is off), thereby applying braking torque and collecting energy to charge the HV battery 13.

  In addition, hybrid vehicle 100 power-controls motor MG2 in the reverse rotation direction with respect to forward travel during backward travel.

  That is, hybrid vehicle 100 intermittently operates engine 1 based on the traveling state, the SOC of battery module 131, and the like. For example, the hybrid vehicle 100 starts the engine 1 when the required driving force (total output) increases when the operation of the engine 1 is stopped, or when the SOC of the battery module 131 decreases. It is configured as follows.

-Control when overcoming steps-
Next, with reference to FIG. 4 and FIG. 5, the control at the time of overcoming the step of the hybrid vehicle 100 according to the present embodiment will be described. The following control is repeatedly performed when the hybrid system is activated (during intermittent operation of the engine 1), and is performed in parallel with normal traveling control and the like. Here, the intermittent operation of the engine 1 is a state in which the start and stop of the engine 1 are allowed (a state in which the intermittent operation of the engine 1 is not prohibited). The following steps are executed by the HVECU 11 (see FIG. 2).

  First, in step S1 of FIG. 4, it is determined whether or not the shift position is a travel position. The travel positions are the D position, the B position, and the R position. If it is determined that the travel position is the D position, the B position, or the R position, the process proceeds to step S2. On the other hand, when it is determined that it is not the traveling position (N position or P position), the process returns.

  Next, in step S2, it is determined whether or not the brake and the parking brake are off. If it is determined that the brake and the parking brake are off, the process proceeds to step S3. On the other hand, when it is determined that the brake and the parking brake are not off (the brake or the parking brake is on), the process proceeds to return. Whether or not the brake is off is determined based on the detection result of the brake pedal position sensor 23, for example. Whether the parking brake is off is determined based on, for example, the operating state of the parking lock mechanism.

  Next, in step S3, it is determined whether or not the road gradient (inclined road surface) is flat. If it is determined that the road gradient is flat, the process proceeds to step S4. On the other hand, if it is determined that the road gradient is not flat (the road is uphill or downhill), the process returns. The road gradient is determined based on detection results of the yaw rate sensor 27 and the linear G sensor 28, for example.

  Next, step determination processing is performed in step S4. This level difference determination process is a process for determining whether or not there is a level difference on the road surface.

  Specifically, in step S11 of FIG. 5, it is determined whether or not the absolute value of the detection result (vehicle speed V) of the vehicle speed sensor 21 is equal to or less than the threshold value Vt. The threshold value Vt is set in advance, and is set, for example, between a vehicle speed at which it can be determined that the vehicle is stopped and a creep vehicle speed on a flat road surface. When it is determined that the absolute value of the vehicle speed V is equal to or less than the threshold value Vt, the process proceeds to step S12. On the other hand, if it is determined that the absolute value of the vehicle speed V is not less than or equal to the threshold value Vt, it is determined in step S14 that there is no step and the process proceeds to the end.

  Next, in step S12, it is determined whether or not the detection result of the accelerator pedal position sensor 22 (the opening APO of the accelerator pedal 22a) is equal to or greater than a threshold value APOt. The threshold value APOt is set in advance, and is set to a value that can be determined that the driver has intentionally stepped on the accelerator pedal 22a, for example. If it is determined that the opening APO of the accelerator pedal 22a is equal to or greater than the threshold value APOt, it is determined in step S13 that a step is present, and the process proceeds to the end. On the other hand, when it is determined that the opening degree APO of the accelerator pedal 22a is not equal to or greater than the threshold value APOt, it is determined in step S14 that there is no step and the process proceeds to the end.

  That is, in this step determination process, based on the detection results of the vehicle speed sensor 21 and the accelerator pedal position sensor 22, it is determined that the vehicle speed corresponding to the requested driving force (the driving force output to the front wheels 8) has not been obtained. If it is determined that there is a level difference. That is, there is a step when the accelerator pedal 22a is intentionally depressed by the driver but the vehicle speed is not in accordance with the depression amount (for example, when the vehicle speed is equal to or less than the creep vehicle speed). Then, it is determined. On the other hand, when the vehicle speed exceeds the creep vehicle speed, for example, and when the accelerator pedal 22a is not depressed by the driver, it is determined that there is no step.

  Then, in step S5 of FIG. 4, it is determined whether or not it is determined that there is a step by the step determination process described above. And when it determines with a level | step difference existing, it moves to step S6. On the other hand, if it is determined that there is no step, the process returns.

  Next, in step S6, it is determined whether or not the engine 1 is in a stopped state. If it is determined that the engine 1 is stopped, the process proceeds to step S7. On the other hand, if it is determined that the engine 1 is not in a stopped state (the engine 1 is in an operating state), the engine 1 is not started when the level difference is overcome, and therefore the process directly returns.

  Next, in step S7, starting of the engine 1 is prohibited for a preset period T, and the process returns. Note that, during this period T, for example, even if the EV running in which the engine 1 is stopped and only the motor MG2 is driven is continued, the motor MG2 is not overheated, the inverter 143 is overheated, and the battery module 131 is not overdischarged. It is a period.

-Effect-
In the present embodiment, as described above, in the hybrid vehicle 100 in which the engine 1 is configured to be capable of intermittent operation, when it is determined that there is a step, the engine 1 is prohibited from starting for a preset period T. Thus, it is possible to suppress the engine 1 from being started when overcoming the level difference, and thus it is possible to suppress the driver from feeling uncomfortable. For example, when the hybrid vehicle 100 gets over a step, the accelerator pedal 22a is depressed by the driver, and the start of the engine 1 is prohibited even when the required value of the driving force output to the front wheels 8 increases. Since it is possible to suppress the start of the engine 1 from overlapping at the timing of stepping over the step, it is possible to suppress the driver from feeling uncomfortable. As a result, it is possible to suppress a decrease in drivability.

  In the present embodiment, it can be easily determined whether or not there is a step by determining that a step exists when the vehicle speed corresponding to the requested driving force is not obtained.

-Other embodiments-
In addition, embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, the technical scope of the present invention includes all modifications within the meaning and scope equivalent to the scope of the claims.

  For example, in the present embodiment, an example in which the present invention is applied to the FF hybrid vehicle 100 has been described. However, the present invention is not limited thereto, and the present invention may be applied to an FR or 4WD hybrid vehicle.

  Further, in the present embodiment, an example in which two motor generators (the generator MG1 and the motor MG2) are provided in the hybrid vehicle 100 has been described. It may be provided. For example, in the hybrid vehicle 100 according to the present embodiment, a motor generator that drives the rear wheel axle may be provided in addition to the generator MG1 and the motor MG2.

  In the present embodiment, the example in which it is determined whether or not there is a level difference based on the detection results of the vehicle speed sensor 21 and the accelerator pedal position sensor 22 is shown. However, the present invention is not limited to this. (Not shown) may be provided, and it may be determined whether or not there is a step based on an image captured by the imaging device.

  In the present embodiment, the step determination process is performed when the road gradient is flat, and the engine 1 is prohibited from starting when it is determined that a step exists. However, the present invention is not limited to this. The step determination process may be performed when is a downward gradient or an upward gradient, and the engine 1 may be prohibited from starting when it is determined that a step exists. In the step determination process in this case, the threshold value APOt may be corrected according to the degree of gradient. For example, in the case of an upward gradient, the threshold value APOt may be increased compared to a flat case. In the case of a downward slope, the same threshold value APOt as in the flat case may be used.

  In the present embodiment, the period T during which the start of the engine 1 is prohibited may be a fixed period or an indefinite period (variable period). For example, the period T may be calculated based on the SOC of the battery module 131 or the like.

  In the present embodiment, during the period T, the control over the step may not be performed, and the control over the step may be performed again after the period T elapses.

1 engine 8 front wheel (drive wheel)
11 HVECU (control device)
21 Vehicle speed sensor 22 Accelerator pedal position sensor 22a Accelerator pedal 100 Hybrid vehicle MG2 Motor (electric motor)

Claims (3)

An engine and an electric motor for driving the drive wheels;
A control device for controlling the engine and the electric motor,
The control device is configured to be capable of intermittent operation of the engine, and is configured to prohibit starting of the engine when overcoming a step on a road surface during intermittent operation of the engine. vehicle. The hybrid vehicle according to claim 1,
The control device determines that there is a step when the vehicle speed corresponding to the driving force output to the driving wheel is not obtained, and starts the engine for a preset period when it is determined that there is a step. The hybrid vehicle is configured to prohibit the vehicle. The hybrid vehicle according to claim 2,
A vehicle speed sensor for detecting the vehicle speed;
An accelerator pedal position sensor for detecting the amount of depression of the accelerator pedal,
The hybrid vehicle, wherein the control device is configured to determine whether or not a step exists based on detection results of the vehicle speed sensor and the accelerator pedal position sensor.

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