JP2018001865A - Hybrid vehicle - Google Patents

Abstract

[PROBLEMS] To suppress deterioration of fuel consumption. When the accelerator is off, the braking force reduction control is executed to reduce the braking force applied to the vehicle by regenerative driving of the motor when the predetermined condition is satisfied as compared to when the predetermined condition is not satisfied. When the storage ratio of the battery is less than or equal to a predetermined ratio, engine power generation control is executed in which the power is generated by the generator using the power from the engine and the battery is charged. When the engine power generation control is executed when the reduction condition is satisfied when the accelerator is off, the braking force is increased compared to when the engine power generation control is not executed. [Selection] Figure 2

Description

  The present invention relates to a hybrid vehicle, and more particularly, to a hybrid vehicle including an engine, a generator, a motor, and a battery.

  Conventionally, in this type of hybrid vehicle, an engine and a first motor are connected to a drive shaft connected to drive wheels via a planetary gear, and a second motor is connected to the drive shaft. The first motor and the second motor In a hybrid vehicle that exchanges electric power with a battery, a vehicle that applies braking force to the vehicle by engine motoring by the first motor and regenerative driving of the second motor when the accelerator is off has been proposed (for example, Patent Documents). 1). In this hybrid vehicle, when the accelerator is off, the braking force applied to the vehicle is made smaller in the eco mode than in the normal mode.

JP 2013-35370 A

  In such a hybrid vehicle, when the storage ratio of the battery is less than or equal to a predetermined ratio when the accelerator is off, the second motor is regeneratively driven and power generation by the first motor using the power from the engine (to promote battery charging ( Hereinafter, there is one that performs “engine power generation”. In this case, when the engine power generation is performed in the eco mode when the accelerator is off, if the torque (braking force applied to the vehicle) due to the regenerative drive of the second motor is relatively small, the electric power due to the regenerative drive of the second motor. Is relatively small, and the charging power of the battery according to the sum of the electric power and the generated electric power of the first motor does not increase so much, so that the time until the storage ratio of the battery becomes larger than a predetermined ratio, that is, the engine The engine operating time for power generation may be relatively long. Basically, the charging efficiency of the battery by engine power generation is lower than the charging efficiency of the battery by regenerative driving of the second motor, so that the fuel consumption deteriorates when the engine operating time for engine power generation becomes relatively long. There are concerns.

  The main purpose of the hybrid vehicle of the present invention is to suppress deterioration in fuel consumption.

  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
An engine for traveling,
A generator that generates power using power from the engine;
A motor for traveling,
A battery that exchanges power with the generator and the motor;
When the accelerator is off, the braking force reduction control is executed to reduce the braking force applied to the vehicle by regenerative driving of the motor when the braking force reduction condition is satisfied, compared to when the reduction condition is not satisfied. And a control device that executes engine power generation control for generating power by the generator using power from the engine when the storage ratio of the battery is equal to or less than a predetermined ratio;
A hybrid vehicle comprising:
When the engine power generation control is being executed when the reduction condition is satisfied when the accelerator is off, the control device increases the braking force compared to when the engine power generation control is not being executed. Enlarge,
This is the gist.

  In the hybrid vehicle of the present invention, when the accelerator is off, the braking force applied to the vehicle by the regenerative driving of the motor is reduced when the braking force reduction condition is satisfied, compared to when the reduction condition is not satisfied. While executing the braking force reduction control, the engine power generation control is performed in which the battery is charged by generating power by the generator using the power from the engine when the storage ratio of the battery is equal to or less than a predetermined ratio. When the engine power generation control is executed when the reduction condition is satisfied when the accelerator is off, the braking force is increased compared to when the engine power generation control is not executed. As a result, when the accelerator is off and the reduction condition is satisfied and the engine power generation control is being executed, the power generated by the motor regenerative drive increases, and the battery charge power (the power and power generated by the motor regenerative drive) increases. (The power corresponding to the sum of the generated power of the machine) can be increased, and therefore the time until the battery storage ratio becomes larger than the predetermined ratio, that is, the execution time of the engine power generation control can be shortened. . As a result, the engine operating time for executing the engine power generation control can be shortened, so that deterioration of fuel consumption can be suppressed. Here, examples of the “reduction condition” include a condition in which an eco mode in which fuel efficiency is given priority over the normal mode is selected. Note that when the accelerator is off and the reduction condition is satisfied and the engine power generation control is being executed, the braking force reduction control is executed and the braking force is more than when the reduction condition is not satisfied. The braking force may be reduced, or the braking force reduction control may not be executed, and the braking force may be the same as when the reduction condition is not satisfied. In the latter case, when the accelerator is off and the reduction condition is satisfied, the braking force reduction control is executed when the engine power generation control is not executed, and the braking force reduction control is executed when the engine power generation control is executed. Do not execute.

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 control routine performed by HVECU70 of an Example. It is explanatory drawing which shows an example of the 1st-3rd map for the setting of request | requirement torque Td *. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification.

  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.

  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 to control the operation of the engine 22, for example, a crank angle θcr from a crank position sensor that detects the rotational position of the crankshaft 26 of the engine 22 from an input port. ing. 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 signals input to the battery ECU 52 include a battery voltage Vb from a voltage sensor 51 a installed between terminals of the battery 50, a battery current Ib from a current sensor 51 b attached to an output terminal of the battery 50, and a battery 50. The battery temperature Tb from the temperature sensor 51c attached to can be mentioned. The battery ECU 52 is connected to the HVECU 70 via a communication port. The battery ECU 52 calculates the storage ratio SOC based on the integrated value of the battery current Ib from the 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. Here, the shift position SP includes a parking position (P position), a reverse position (R position), a neutral position (N position), a forward position (D position), and the like. 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. Furthermore, an eco-switch signal from the eco-switch 90 that instructs the eco-mode that gives higher priority to fuel efficiency than the normal mode can be cited as the travel mode Md. 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.

In the hybrid vehicle 20 of the embodiment thus configured, the required driving force of the drive shaft 36 is set based on the accelerator opening Acc and the vehicle speed V, and the required power corresponding to the required driving force is output to the drive shaft 36. In addition, the engine 22 and the motors MG1, MG2 are controlled to operate. As operation modes of the engine 22 and the motors MG1, MG2, there are the following modes (1) to (3).
(1) Torque conversion operation mode: The engine 22 is operated and controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is transmitted to the planetary gear 30 and the motors MG1 and MG2. (2) Charging / discharging operation mode: sum of required power and electric power necessary for charging / discharging of the battery 50. In this mode, the motor MG1 and MG2 are driven and controlled so that the required power is output to the drive shaft 36. The engine 22 is operated and controlled so that the power suitable for the engine 22 is output from the engine 22, and all or a part of the power output from the engine 22 is charged with the battery 50 by the planetary gear 30 and the motors MG1 and MG2. The motors MG1 and MG2 are driven so that the torque is converted by the motor and the required power is output to the drive shaft 36. Gosuru mode (3) motor drive mode: stop the operation of the engine 22, required power to drive control of the motor MG2 to be outputted to the drive shaft 36 mode

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the control of the motor MG2 when the accelerator is off during traveling will be described. FIG. 2 is a flowchart illustrating an example of a control routine executed by the HVECU 70 of the embodiment. This routine is repeatedly executed every predetermined time (for example, several milliseconds) when the accelerator is off.

  When the accelerator is off, in parallel with this routine, the engine 22 and the motor MG1 are controlled as follows by cooperative control of the HVECU 70, the engine ECU 24, and the motor ECU 40. When the storage ratio SOC of the battery 50 is larger than a threshold value Sref (for example, 35%, 40%, 45%, etc.) and the heating request for the heating device using the engine 22 as a heat source is not made, the engine 22 is stopped. At the same time, the motor MG1 is controlled so that no torque is output from the motor MG1. When the storage ratio SOC of the battery 50 is larger than the threshold value Sref and the heating request for the heating device is made, the engine 22 is controlled so that the engine 22 is operated independently (no-load operation), and torque is generated from the motor MG1. The motor MG1 is controlled so that it is not output. When power storage ratio SOC of battery 50 is equal to or less than threshold value Sref, engine 22 and motor MG1 are controlled such that engine 22 is loaded and power is generated by motor MG1 using power from engine 22. Hereinafter, this control is referred to as “engine power generation control”.

  When the accelerator-off-time control routine is executed, the HVECU 70 first inputs data such as the vehicle speed V, the eco mode flag Feco, the operation flag Feg, and the engine power generation flag Fge (step S100). Here, the vehicle speed V is input by the vehicle speed sensor 88. Based on the eco switch signal from the eco switch 90, the eco mode flag Feco is set to a value of 0 when the eco switch 90 is off (in normal mode) and when the eco switch 90 is on (in eco mode). When the value 1 is set. As the operation flag Feg, the value 1 is set when the engine 22 is operated, and the value 0 is set when the engine 22 is stopped, and is input from the engine ECU 24 by communication. The engine power generation flag Fge is set to a value of 1 when the engine power generation control is being executed and to a value of 0 when the engine power generation control is not being executed.

  When the data is input in this way, the value of the input eco mode flag Feco is checked (step S110). This process is a process for determining whether or not a condition for reducing the braking force when the accelerator is off is satisfied. When the eco mode flag Feco is 0, it is determined that the eco switch 90 is off (normal mode) and the braking force reduction condition is not satisfied, and the vehicle is requested using the vehicle speed V and the first map. The required torque Td * (required for the drive shaft 36) is set (step S120). The first map and second and third maps described later are maps showing the relationship between the vehicle speed V and the required torque Td *. An example of the first to third maps is shown in FIG. In the first to third maps, when the required torque Td * is negative, it means that a braking torque is required for the vehicle (drive shaft 36).

  When the required torque Td * is set in this way, the set required torque Td * is set as the torque command Tm2 * of the motor MG2 and transmitted to the motor ECU 40 (step S170), and this routine is terminated. When motor ECU 40 receives torque command Tm2 * of motor MG2, motor ECU 40 performs switching control of a plurality of switching elements of inverter 42 such that motor MG2 is driven by torque command Tm2 *. When the required torque Td *, that is, the torque command Tm2 * of the motor MG2 is negative (when it is braking torque), negative torque, that is, braking torque is output from the motor MG2 to the drive shaft 36.

  When the eco mode flag Feco is 1 in step S110, it is determined that the eco switch 90 is on (eco mode) and the braking force reduction condition is satisfied, and the value of the operation flag Feg is examined (step S130). When the driving flag Feg is 0, it is determined that the engine 22 is stopped, and the required torque Td * is set using the vehicle speed V and the second map of FIG. 3 (step S140). The requested torque Td * is set to the torque command Tm2 * of the motor MG2 (step S170), and this routine is finished. Here, in the second map, the required torque Td * is set so as to be larger than the first map (smaller as the braking torque). Thereby, when the engine 22 is stopped in the eco mode, the braking force applied to the vehicle can be reduced as compared with the normal mode.

  When the operation flag Feg is 1 in step S130, it is determined that the engine 22 is operating (self-sustaining operation or load operation), and the value of the engine power generation flag Fge is examined (step S150). When the engine power generation flag Fge is 0, it is determined that the engine 22 is operating independently and engine power generation control is not performed, and the required torque Td * is calculated using the vehicle speed V and the second map of FIG. In step S140, the set required torque Td * is set to the torque command Tm2 * of the motor MG2 (step S170), and this routine ends. Thereby, even when the engine 22 is operated in the eco mode but the engine power generation control is not performed, the braking force applied to the vehicle can be reduced as compared with the normal mode.

  When the engine power generation flag Fge is 1 in step S150, it is determined that the engine 22 is under load operation and engine power generation control is being executed, and the required torque Td * is determined using the vehicle speed V and the third map of FIG. Is set (step S160), the set required torque Td * is set to the torque command Tm2 * of the motor MG2 (step S170), and this routine is terminated. Here, in the third map, the required torque Td * is set so as to be larger than the first map (smaller as the braking torque) and smaller than the second map (larger as the braking torque). Set.

  As described above, when the eco mode flag Feco is 1 in step S110, it is determined that the eco switch 90 is on (eco mode) and the braking force reduction condition is satisfied, and the eco switch 90 is off (normal). Mode), the required torque Td *, that is, the torque command Tm2 * of the motor MG2 is increased (the braking force is decreased) to control the motor MG2 as compared to when it is determined that the braking force reduction condition is not satisfied. To do. Therefore, hereinafter, this control is referred to as “braking force reduction control”.

  When the demand torque Td * is set using the second map regardless of whether or not the engine power generation control is being executed as the braking force reduction control when the accelerator is off and in the eco mode, it is applied to the vehicle. The braking torque becomes relatively small, and the electric power due to the regenerative driving of the motor MG2 becomes relatively small. When the engine power generation control is being performed in the eco mode when the accelerator is off, if the power generated by the regenerative drive of the motor MG2 is relatively small, the charging power of the battery 50 corresponding to the sum of this power and the power generated by the motor MG1 is not much. By not increasing, the time until the power storage ratio SOC of the battery 50 becomes larger than the threshold value Sref, that is, the execution time of engine power generation control may be relatively long. Basically, the charging efficiency of the battery 50 due to the execution of the engine power generation control is lower than the charging efficiency of the battery 50 due to the regenerative drive of the motor MG2, so the operation time of the engine 22 for executing the engine power generation control is compared. There is a concern that the fuel economy will deteriorate if the target is too long. In the embodiment, when the accelerator is off and in the eco mode, when the engine 22 is stopped or autonomously operated and the engine power generation control is not performed, the required torque Td * is set using the second map, and the engine 22 is operated. When the engine power generation control is performed under load operation, the required torque Td * is set using the third map, so that the required torque Td * when the engine power generation control is performed is used for the engine power generation control. It is smaller than the required torque Td * when there is not (the braking force is increased). As a result, the electric power generated by regenerative driving of motor MG2 can be increased to increase the charging power of battery 50. Therefore, the time until the storage ratio SOC of battery 50 becomes larger than threshold value Sref, that is, the engine power generation The execution time of control can be shortened. As a result, since the operation time of the engine 22 for executing the engine power generation control can be shortened, deterioration of fuel consumption can be suppressed.

  In the hybrid vehicle 20 of the embodiment described above, when the accelerator is off and in the eco mode, the required torque Td * when the engine power generation control is performed is changed to the required torque Td * when the engine power generation control is not performed. Compared to a smaller value (to increase the braking force). Thereby, since the charging power of the battery 50 can be increased, the time until the storage ratio SOC of the battery 50 becomes larger than the threshold value Sref, that is, the execution time of the engine power generation control can be shortened. As a result, since the operation time of the engine 22 for executing the engine power generation control can be shortened, deterioration of fuel consumption can be suppressed.

  In the hybrid vehicle 20 of the embodiment, when the engine power generation control is not performed when the accelerator is off and in the eco mode, the required torque Td * is set using the second map, and when the engine power generation control is performed, The required torque Td * is set using the third map. However, when engine power generation control is performed in the eco mode when the accelerator is off, the required torque Td * is set using the first map (similar to when the braking force reduction control is not executed). Also good. In this case, when the accelerator is off and in the eco mode, when the engine power generation control is not performed, the braking force reduction control is executed, and when the engine power generation control is performed, the braking force reduction control is not executed.

  In the hybrid vehicle 20 of the embodiment, the engine ECU 24, the motor ECU 40, and the HVECU 70 are provided. However, the engine ECU 24, the motor ECU 40, and the HVECU 70 may be configured as a single electronic control unit.

  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, and the motor MG2 is connected to the drive shaft 36. However, as shown in the hybrid vehicle 120 of the modified example of FIG. 4, the motor MG1 for power generation is connected to the output shaft of the engine 22, and the motor MG2 for traveling is connected to the drive shaft 36 connected to the drive wheels 39a and 39b. It is good also as composition of what is called a series hybrid car to connect.

  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 MG1 corresponds to the “generator”, the motor MG2 corresponds to the “motor”, the battery 50 corresponds to the “battery, the HVECU 70, the engine ECU 24, and the motor. The ECU 40 corresponds 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 can be used in the manufacturing industry of hybrid vehicles.

  20, 120 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 sensor, 50 battery, 51a Voltage sensor, 51b Current sensor, 51c Temperature sensor, 52 Battery electronic control unit (battery ECU), 54 Electric power Line, 70 hybrid electronic control unit (HV ECU), 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position Deployment sensor, 85 brake pedal, 86 a brake pedal position sensor, 88 vehicle speed sensor, 90 eco switch, MG1, MG2 motor.

Claims (1)

An engine for traveling,
A generator that generates power using power from the engine;
A motor for traveling,
A battery that exchanges power with the generator and the motor;
When the accelerator is off, the braking force reduction control is executed to reduce the braking force applied to the vehicle by regenerative driving of the motor when the braking force reduction condition is satisfied, compared to when the reduction condition is not satisfied. And a control device that executes engine power generation control for generating power by the generator using power from the engine when the storage ratio of the battery is equal to or less than a predetermined ratio;
A hybrid vehicle comprising:
When the engine power generation control is being executed when the reduction condition is satisfied when the accelerator is off, the control device increases the braking force compared to when the engine power generation control is not being executed. Enlarge,
Hybrid car.

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