JP6876372B2 - Hybrid vehicle - Google Patents

Description

The present invention relates to a hybrid vehicle.

The hybrid vehicle uses regenerative power generation during deceleration to recover the amount of battery charge that has decreased during acceleration. During this deceleration, the internal combustion engine is stopped or fuel injection to the internal combustion engine is stopped.

Patent Document 1 proposes a technique for prohibiting the regeneration of electric power by the regenerative brake when the charge capacity of the battery becomes low when the fuel is cut and the electric power by the regenerative brake is executed when the vehicle is decelerated.

Japanese Unexamined Patent Publication No. 2011-121423

When the hybrid vehicle ends the deceleration state and tries to re-accelerate, the power of the internal combustion engine may also be required depending on the acceleration request amount of the driver. However, as described above, at the time of deceleration, the internal combustion engine is stopped or the fuel injection to the internal combustion engine is stopped, so that there is a problem that the driver cannot quickly respond to the acceleration request.

Further, the battery has a characteristic that when the temperature of the battery becomes low, the ability to accept charge decreases as compared with the case of normal temperature.

Therefore, when the temperature of the battery is low, the amount of power generation (regenerative power generation amount) at room temperature is not required.

In this environment where the battery temperature is low, when the regenerative power generation control in which the engine is stopped is executed when the hybrid vehicle is decelerating, the regenerative power generation amount is large, so that the battery charge state immediately reaches the rechargeable value. Therefore, the generated regenerative power was not effectively utilized.

However, the technique proposed in Patent Document 1 does not consider the responsiveness to the driver's acceleration request and the battery temperature characteristics.

The present invention provides a hybrid vehicle having deceleration control that takes into consideration two factors, the battery temperature characteristic, which is the receiving side of the regenerated electric power, and the responsiveness when the driver requests acceleration during the regenerative power generation. The purpose is to do.

One aspect of the hybrid vehicle according to the present invention that solves the above problems is an internal combustion engine, a transmission that shifts the rotation output from the internal combustion engine to drive drive wheels via a drive shaft, and the drive shaft. A hybrid vehicle provided with a motor generator that is always connected and a battery that transfers power to and from the motor generator, and is driven by power output from at least one of the internal combustion engine and the motor generator. A control unit that controls the running of the hybrid vehicle, a battery temperature detecting means that detects the temperature of the battery, and a clutch that connects or disconnects a power transmission path between the internal combustion engine and the drive wheels. When the vehicle is in a decelerated state and the battery temperature detected by the battery temperature detecting means is equal to or higher than a set value, the control unit causes the clutch to disconnect the power transmission path to regenerate the vehicle. In the first mode for executing power generation control and when the vehicle is in a decelerated state and the battery temperature detected by the battery temperature detecting means is less than a set value, the power transmission path is connected to the clutch. , The internal combustion engine and the drive wheel are connected to execute the regenerative power generation control, but the amount of regenerative power generation is smaller than that of the first mode, and when the state shifts to the acceleration state, the vehicle accelerates in a shorter time than the first mode. It has a second mode in which driving can be performed.

The present invention has a control content that takes into consideration two factors of the temperature characteristic of the battery and the responsiveness when the driver requests acceleration during regenerative power generation in the deceleration control of the hybrid vehicle. Even when the temperature is low, regenerative power generation is not wasted. It also has deceleration control that responds quickly to the driver's acceleration demands when the battery temperature is low.

FIG. 1 is a configuration diagram showing a main part of a hybrid vehicle according to an embodiment of the present invention. FIG. 2 is a functional block diagram of a hybrid vehicle according to an embodiment of the present invention. FIG. 3 is a flowchart showing a deceleration control operation of the hybrid vehicle according to the embodiment of the present invention.

Hereinafter, the hybrid vehicle according to the embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the hybrid vehicle 1 includes an HCU (Hybrid Control Unit) 10 that comprehensively controls an engine 2, a transmission 3, a motor generator 4, a drive wheel 5, and a hybrid vehicle 1 as an internal combustion engine. The ECM (Engine Control Module) 11 that controls the engine 2, the TCM (Transmission Control Module) 12 that controls the transmission 3, the ISGCM (Integrated Starter Generator Control Module) 13, the INVCM (Invertor Control Module) 14, and so on. It includes a low-voltage BMS (Battery Management System) 15 and a high-voltage BMS 16.

A plurality of cylinders are formed in the engine 2. In the present embodiment, the engine 2 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder.

An ISG (Integrated Starter Generator) 20 and a starter 21 are connected to the engine 2. The ISG 20 is connected to the crankshaft 18 of the engine 2 via a belt 22 or the like. The ISG 20 has a function of an electric motor that starts the engine 2 by rotating by being supplied with electric power, and a function of a generator that converts the rotational force input from the crankshaft 18 into electric power.

In the present embodiment, the ISG 20 functions as an electric motor under the control of the ISGCM 13 to restart the engine 2 from a stopped state by the idling stop function. The ISG 20 can also assist the running of the hybrid vehicle 1 by functioning as an electric motor.

The starter 21 includes a motor (not shown) and a pinion gear. The starter 21 rotates the crankshaft 18 by rotating the motor to give the engine 2 a rotational force at the time of starting. In this way, the engine 2 is started by the starter 21 and restarted by the ISG 20 from the stopped state by the idling stop function.

The transmission 3 shifts the rotation output from the engine 2 and drives the drive wheels 5 via the drive shaft 23. The transmission 3 includes a constantly meshing type transmission mechanism 25 composed of a parallel shaft gear mechanism, a clutch 26 composed of a normally closed type dry clutch, a differential mechanism 27, and an actuator (not shown).

The transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and the actuator controlled by the TCM 12 switches the shift stage in the transmission mechanism 25 and connects and disengages the clutch 26. The differential mechanism 27 transmits the power output by the transmission mechanism 25 to the drive shaft 23.

The motor generator 4 is connected to the differential mechanism 27 via a power transmission mechanism 28 such as a chain. The motor generator 4 functions as an electric motor.

As described above, the hybrid vehicle 1 constitutes a parallel hybrid system in which the powers of both the engine 2 and the motor generator 4 can be used to drive the vehicle, and at least one of the engine 2 and the motor generator 4 outputs. It is designed to run by power.

The motor generator 4 also functions as a generator, and generates electricity by traveling the hybrid vehicle 1. The motor generator 4 may be connected to any part of the power transmission path from the engine 2 to the drive wheels 5 so as to be able to transmit power, and does not necessarily have to be connected to the differential mechanism 27.

The hybrid vehicle 1 includes a first power storage device 30, a low voltage power pack 32 including a second power storage device 31, a high voltage power pack 34 including a third power storage device 33, a high voltage cable 35, and a low voltage cable 36. And have.

The first power storage device 30, the second power storage device 31, and the third power storage device 33 are composed of a rechargeable secondary battery. The first power storage device 30 is made of a lead battery. The second power storage device 31 is a power storage device having a higher output and a higher energy density than the first power storage device 30.

The second power storage device 31 can be charged in a shorter time than the first power storage device 30. In the present embodiment, the second power storage device 31 is composed of a lithium ion battery. The second power storage device 31 may be a nickel-metal hydride storage battery.

The first power storage device 30 and the second power storage device 31 are low-voltage batteries in which the number of cells and the like are set so as to generate an output voltage of about 12 V. The third power storage device 33 is made of, for example, a lithium ion battery.

The third power storage device 33 is a high-voltage battery in which the number of cells and the like are set so as to generate a higher voltage than the first power storage device 30 and the second power storage device 31, and for example, an output voltage of 100 V is generated. The state such as the remaining capacity of the third power storage device 33 is managed by the high voltage BMS 16.

The hybrid vehicle 1 is provided with a general load 37 as an electric load and a protected load 38. The general load 37 and the protected load 38 are electrical loads other than the starter 21 and the ISG 20.

The protected load 38 is an electric load that is always required to have a stable power supply. The protected load 38 includes a stability control device 38A that prevents the hybrid vehicle 1 from skidding, an electric power steering control device 38B that electrically assists the operating force of the steering wheels, and a headlight 38C. The protected load 38 also includes lamps and meters of an instrument panel (not shown) and a car navigation system.

The general load 37 is an electric load that is temporarily used without requiring a stable power supply as compared with the protected load 38. The general load 37 includes, for example, a wiper (not shown) and an electric cooling fan that blows cooling air to the engine 2.

The low-voltage power pack 32 has switches 40 and 41 and a low-voltage BMS 15 in addition to the second power storage device 31. The first power storage device 30 and the second power storage device 31 are connected via a low voltage cable 36 so as to be able to supply electric power to the starter 21, the ISG 20, the general load 37 as an electric load, and the protected load 38. There is. The first power storage device 30 and the second power storage device 31 are electrically connected in parallel to the protected load 38.

The switch 40 is provided on the low voltage cable 36 between the second power storage device 31 and the protected load 38. The switch 41 is provided in the low voltage cable 36 between the first power storage device 30 and the protected load 38.

The low-voltage BMS 15 controls the opening and closing of the switches 40 and 41 to control the charging / discharging of the second power storage device 31 and the power supply to the protected load 38. When the engine 2 is stopped due to idling stop, the low voltage BMS 15 closes the switch 40 and opens the switch 41 to supply electric power from the second power storage device 31 having high output and high energy density to the protected load 38. It is designed to supply.

The low-voltage BMS 15 is the first by closing the switch 40 and opening the switch 41 when the engine 2 is started by the starter 21 and when the engine 2 stopped by the idling stop control is restarted by the ISG 20. Power is supplied from the power storage device 30 to the starter 21 or the ISG 20. When the switch 40 is closed and the switch 41 is opened, electric power is also supplied from the first power storage device 30 to the general load 37.

As described above, the first power storage device 30 is adapted to supply at least electric power to the starter 21 and the ISG 20 as starting devices for starting the engine 2. The second power storage device 31 is adapted to supply at least power to the general load 37 and the protected load 38.

The second power storage device 31 is connected so as to be able to supply power to both the general load 37 and the protected load 38, but preferentially supplies power to the protected load 38, which is always required to have a stable power supply. The switches 40 and 41 are controlled by the low voltage BMS 15.

The low-voltage BMS 15 stabilizes the protected load 38 while considering the charging state (remaining charge) of the first power storage device 30 and the second power storage device 31 and the operation requirements for the general load 37 and the protected load 38. The switches 40 and 41 may be controlled differently from the above-described example in order to give priority to the operation.

The high-voltage power pack 34 has an inverter 45, an INVCM 14, and a high-voltage BMS 16 in addition to the third power storage device 33. The high-voltage power pack 34 is connected via a high-voltage cable 35 so as to be able to supply electric power to the motor generator 4.

The inverter 45 is controlled by the INVCM 14 to convert the AC power applied to the high voltage cable 35 and the DC power applied to the third power storage device 33 to each other. For example, when the motor generator 4 is forced to run, the INVCM 14 converts the DC power discharged by the third power storage device 33 into AC power by the inverter 45 and supplies the DC power to the motor generator 4.

When the motor generator 4 is regenerated, the INVCM 14 converts the AC power generated by the motor generator 4 into DC power by the inverter 45 and charges the third power storage device 33.

The HCU10, ECM11, TCM12, ISGCM13, INVCM14, low-voltage BMS15, and high-voltage BMS16 each have a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), backup data, and the like. It consists of a computer unit having a flash memory for storing, an input port, and an output port.

The ROM of these computer units stores various constants, various maps, and the like, as well as programs for making the computer unit function as HCU10, ECM11, TCM12, ISGCM13, INVCM14, low-voltage BMS15, and high-voltage BMS16, respectively. ..

That is, when the CPU executes the program stored in the ROM using the RAM as the work area, these computer units are used as the HCU10, ECM11, TCM12, ISGCM13, INVCM14, low voltage BMS15, and high voltage BMS16 in the present embodiment. Each works.

In the present embodiment, the ECM 11 is adapted to execute idling stop control. In this idling stop control, the ECM 11 stops the engine 2 when a predetermined stop condition is satisfied, and drives the ISG 20 via the ISGCM 13 to restart the engine 2 when the predetermined restart condition is satisfied. .. Therefore, unnecessary idling of the engine 2 is not performed, and the fuel efficiency of the hybrid vehicle 1 can be improved.

The hybrid vehicle 1 is provided with CAN communication lines 48 and 49 for forming an in-vehicle LAN (Local Area Network) conforming to a standard such as CAN (Controller Area Network).

The HCU 10 is connected to the INVCM 14 and the high voltage BMS 16 by a CAN communication line 48. The HCU 10, INVCM14, and high-voltage BMS16 mutually transmit and receive signals such as control signals via the CAN communication line 48.

The HCU 10 is connected to the ECM 11, TCM 12, ISGCM 13 and low voltage BMS 15 by a CAN communication line 49. The HCU10, ECM11, TCM12, ISGCM13, and low-voltage BMS15 mutually transmit and receive signals such as control signals via the CAN communication line 49.

As shown in FIG. 2, the input port of the HCU 10 detects the temperature of the accelerator opening sensor 52 that detects the operation amount of the accelerator pedal 51 (hereinafter, simply referred to as “accelerator opening”) and the temperature of the third power storage device 33. A temperature sensor 53 as a temperature detecting means is connected.

When the accelerator opening degree detected by the accelerator opening degree sensor 52 is substantially 0 when the hybrid vehicle 1 is traveling, the HCU 10 determines that the hybrid vehicle 1 is in the deceleration state.

The HCU 10 has a function of keeping the hybrid vehicle 1 in a driving state or a stopped state by the power of only the motor generator 4, and a function of putting the hybrid vehicle 1 in the driving state by the power of both the engine 2 and the motor generator 4, hybrid. The control unit 60 is provided to control the function of charging the third power storage device 33 by using the power generation function of the motor generator 4 in the decelerated state of the vehicle 1.

In this embodiment, among the above-mentioned functions, the function executed in the vehicle deceleration state is used. This will be described in detail below.

The regenerative power generation control of the motor generator 4 executed in the deceleration state of the hybrid vehicle 1 is composed of two modes in which the amount of power generation is different.

The first mode is executed when the temperature (value detected by the temperature sensor 53) of the third power storage device 33 charged by the power generation of the motor generator 4 is equal to or higher than the set value TH.

The second mode is executed when the temperature (value detected by the temperature sensor 53) of the third power storage device 33 charged by the power generation of the motor generator 4 is less than the set value TH.

Each mode will be described in order.

(1st mode)
The HCU 10 uses the power transmitted from the drive wheels 5 to generate electricity in the motor generator 4, and controls the INVCM 14 so that the third power storage device 33 can be charged by the generated power. Since the amount of power generation is not particularly limited, the charging state of the third power storage device 33 is quickly improved.

The HCU 10 controls the TCM 12 in order to release the clutch 26.
The first mode can be applied to either an idle stop state in which the engine 2 is automatically stopped or a state in which idling is maintained.

Further, when it is necessary to execute acceleration using the engine 2 in response to an acceleration request while executing the control of the first mode, the HCU 10 executes the following control in cooperation with the ECM 11 and the TCM 12. When the engine 2 is in the idle stop state during the first mode, the engine 2 is started first, and then the clutch 26 is engaged after the engine is started, and the power of the engine 2 is output to the drive wheels 5. When the engine 2 is in a state of maintaining idling during the first mode, the clutch is changed from the released state to the connected state and the power of the engine 2 is output to the drive wheels 5.

(2nd mode)
The state of the clutch 26 is different from that of the first mode, the clutch 26 is connected, and the engine 2 and the drive wheels 5 are connected. However, the fuel supply to the engine 2 is stopped. This is the so-called fuel cut state during deceleration.

Therefore, in this second mode, when the driver requests acceleration, the acceleration running can be executed only by supplying fuel to the engine 2. That is, the shift can be performed in a shorter time than the shift from the first mode, which requires starting the engine or the shift operation, to the acceleration running.

Here, the acceleration preparation means from the restart of the fuel supply to the engine 2 to the actual acceleration of the vehicle. In other words, if the driver requests acceleration, the second mode takes less time than completing the acceleration preparation from the first mode, which requires starting the engine or shifting gears. It can be said that the preparation for acceleration is completed and acceleration driving becomes possible.

By the way, in this second mode, the power generated during deceleration of the vehicle is distributed and used to maintain the fuel cut during deceleration of the engine 2 and to improve the charging state of the third power storage device 33. To.

Therefore, even in the second mode in which the acceleration traveling can be started in a short time, the charging state of the third power storage device 33 can be improved although the amount of power generation is smaller than that in the first mode.

Therefore, in the second mode in which the amount of power generation is smaller than that in the first mode, the value detected by the temperature sensor 53 is less than the set value, and the charge acceptability is relatively worse than at room temperature. Suitable for charging.

Further, when it is necessary to execute acceleration using the engine 2 in response to an acceleration request while executing the control of the second mode, the HCU 10 executes the following control in cooperation with the ECM 11 and the TCM 12. In this second mode, since the engine 2 is already in operation and the clutch 26 is also connected, the power of the engine 2 is immediately responded to the driver's acceleration request (eg, accelerator petal depression). It can be output to the drive wheel 5.

The deceleration control operation of the hybrid vehicle according to the embodiment of the present invention configured as described above will be described. The deceleration control operation described below is repeatedly executed while the hybrid vehicle 1 is in the deceleration state.

First, in step S1, it is determined whether or not the detection value T of the temperature sensor 53 (simply referred to as “battery temperature” in the figure) is equal to or higher than the set value TH. When it is determined that the detected value T of the temperature sensor 53 is equal to or higher than the set value TH, the HCU 10 advances the deceleration control operation to step S2. When it is determined that the detected value T of the temperature sensor 53 is not equal to or higher than the set value TH, the HCU 10 advances the deceleration control operation to step S3.

In step S2, the HCU 10 is in the first mode. Specifically, the HCU 10 maintains the first mode if it is the first mode, and becomes the first mode if it is the second mode.

After executing the first mode of step S2, the HCU 10 ends the deceleration control operation. After executing the second mode of step S3, the HCU 10 ends the deceleration control operation.

When the driver drives the hybrid vehicle 1, if the charging state of the third power storage device 33 is good, the EV traveling or the motor assist at the time of acceleration is executed. Then, control for recovering the charged state of the third power storage device 33, which has deteriorated due to the execution of these functions, is performed during deceleration.

When the temperature of the third power storage device 33 is equal to or higher than the set value, the hybrid vehicle 1 starts decelerating and selects the first mode having a large amount of regenerative power generation. In this first mode, the amount of regenerative power generation is large, but since the temperature of the third power storage device 33 is normal temperature and there are no restrictions on charge acceptability, the generated power can be stored in the third power storage device 33. is there.

When the temperature of the third power storage device 33 is less than the set value, the hybrid vehicle 1 starts decelerating and selects the second mode in which the amount of regenerative power generation is small. This second mode is suitable for the state of the third power storage device 33, which has a relatively low charge acceptability at a low temperature. Further, in this second mode, smooth acceleration running can be realized when the situation changes from deceleration to acceleration running, so that the responsiveness to the driver's acceleration request is also high.

Although the embodiments of the present invention have been disclosed above, it is clear that the embodiments can be modified without departing from the scope of the present invention. Embodiments of the present invention are disclosed on the premise that the equivalent with such modifications is included in the invention described in the claims.

1 Hybrid vehicle 2 Engine (internal combustion engine)
4 Motor generator 5 Drive wheels 26 Clutch 33 Third power storage device (battery)
53 Temperature sensor (temperature detection means)
60 Control unit

Claims (1)

With an internal combustion engine
A transmission that shifts the rotation output from the internal combustion engine and drives the drive wheels via a drive shaft.
With a motor generator that is always connected to the drive shaft,
A motor generator and a battery for supplying and receiving electric power are provided.
A hybrid vehicle driven by power output from at least one of the internal combustion engine and the motor generator.
A control unit that controls the running of the hybrid vehicle using the power,
A battery temperature detecting means for detecting the battery temperature and
A clutch for connecting or disconnecting a power transmission path between the internal combustion engine and a drive wheel is provided.
The control unit
When the vehicle is in a decelerated state and the battery temperature detected by the battery temperature detecting means is equal to or higher than a set value, the first mode in which the clutch disconnects the power transmission path and executes regenerative power generation control. When,
When the vehicle is in a decelerated state and the battery temperature detected by the battery temperature detecting means is less than a set value, the power transmission path is connected to the clutch to connect the internal combustion engine and the drive wheels. Then, the regenerative power generation control is executed, but the amount of regenerative power generation is smaller than that of the first mode, and when the vehicle shifts to the acceleration state, the second mode is capable of executing the accelerated running of the vehicle in a shorter time than the first mode. A hybrid vehicle characterized by being equipped.

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