WO2013150966A1

WO2013150966A1 - Hybrid vehicle control device and hybrid vehicle control method

Info

Publication number: WO2013150966A1
Application number: PCT/JP2013/059353
Authority: WO
Inventors: 亮路門野; 哲庸森田
Original assignee: 日産自動車株式会社
Priority date: 2012-04-06
Filing date: 2013-03-28
Publication date: 2013-10-10
Also published as: JP2015116832A

Abstract

This hybrid vehicle control device, which enters an HEV mode for traveling by means of driving forces of an engine and a motor-generator when a clutch is engaged, or an EV mode for traveling by means of the driving force of the motor-generator alone when the clutch is disengaged, controls the gear ratio of a transmission so as to achieve a target gear ratio that corresponds to a vehicle speed when the accelerator pedal is determined to have been released in the EV mode or the HEV mode and the charged capacity of a battery is determined to be equal to or greater than a predetermined capacity, and calculates, on the basis of an engine friction torque and a torque that can be regenerated by the motor-generator, a target clutch engagement capacity while the gear ratio is being controlled. Then, the hybrid vehicle control device controls the clutch engagement capacity so as to achieve the target clutch engagement capacity.

Description

Hybrid vehicle control device and hybrid vehicle control method

The present invention relates to a hybrid vehicle control technology.

A hybrid vehicle control device that prevents overcharge of a battery while obtaining a target vehicle deceleration force during a coast in the EV mode is known (see JP2010-143511A).

In the technology described in JP2010-143511A, when the battery charge amount exceeds a predetermined amount during the coasting in the EV mode, the clutch is engaged and the engine friction torque acts as a vehicle deceleration force. In addition, shifting the stepped transmission to the 1st down side cancels the excessive vehicle deceleration force by powering the motor and establishes the total target vehicle deceleration force while preventing overcharging of the battery. I am letting.

However, since the motor is powered, the battery charge SOC changes. Therefore, the engine speed hunts in accordance with the change in the battery charge amount SOC, and the vehicle deceleration force may fluctuate somewhat when the motor generator transitions between regeneration and power running.

An object of the present invention is to provide a control device capable of realizing a target vehicle deceleration force while preventing hunting of the engine rotation speed.

A control apparatus for a hybrid vehicle according to an embodiment includes an engine, a motor generator, a clutch that intermittently connects the engine, and a transmission. When the clutch is engaged, the driving force of the engine and the motor generator is input to the transmission. The vehicle travels in the HEV mode that is transmitted to the shaft. When the clutch is released, the vehicle travels in the EV mode that transmits the driving force of only the motor generator to the input shaft of the transmission. The hybrid vehicle control device determines whether or not an accelerator release determining means for determining whether or not an accelerator pedal is being released, and whether or not a charge amount of a battery that exchanges power with a motor generator is greater than or equal to a predetermined amount. Charge state determination means, engine friction torque calculation means for calculating engine friction torque, motor generator regenerative torque calculation means for calculating torque that can be regenerated by the motor generator, and calculated motor generator regenerative torque are obtained. The motor generator torque control means for controlling the torque of the motor generator, and when the accelerator pedal is released in the EV mode or HEV mode and the battery charge amount is determined to be greater than or equal to a predetermined amount, the target according to the vehicle speed The transmission gear ratio is controlled so that the gear ratio is obtained. A target clutch engagement capacity for calculating a target clutch engagement capacity based on the calculated engine friction torque and the calculated motor generator regenerative torque when the transmission ratio is controlled by the transmission ratio control means Capacity calculation means and clutch engagement capacity control means for controlling the engagement capacity of the clutch so as to obtain the target clutch engagement capacity.

Embodiments of the present invention and advantages of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an overall system diagram showing a hybrid vehicle to which a hybrid vehicle control device according to the first embodiment is applied. FIG. 2 is a control block diagram of the integrated controller. FIG. 3 is a characteristic diagram of the EV / HEV mode selection map. FIG. 4 is a characteristic diagram of the target charge / discharge amount. FIG. 5 is a timing chart of the reference example. FIG. 6 is a timing chart of the first embodiment. FIG. 7 is a control block diagram of the operating point command unit. FIG. 8 is a characteristic diagram showing the relationship between the vehicle speed and the driver requested vehicle braking force. FIG. 9 is a characteristic diagram of the vehicle braking force with respect to the vehicle speed and the gear ratio. FIG. 10 is a characteristic diagram showing the relationship between the vehicle speed and the gear ratio for outputting the driver-requested vehicle braking force by the engine friction torque. FIG. 11 is a flowchart for explaining calculation of the target motor torque, the target gear ratio, and the target first clutch torque capacity. FIG. 12 is a flowchart for explaining calculation of the target motor torque, the target gear ratio, and the target first clutch torque capacity according to the second embodiment.

(First embodiment)
FIG. 1 is an overall system diagram showing a rear-wheel drive hybrid vehicle to which the hybrid vehicle control device in the first embodiment is applied. However, the hybrid vehicle to which the hybrid vehicle control device is applied is not limited to the rear wheel drive vehicle, and may be a front wheel drive vehicle or a four wheel drive vehicle.

The drive system of the hybrid vehicle includes an engine 100, a first clutch CL1, a motor generator 110, a second clutch CL2, an automatic transmission 120, a propeller shaft 130, a differential 140, left and

right drive shafts

151 and 152, and

drive wheels

163 and 164. Have. The motor generator 110 is hereinafter simply referred to as “motor 110”.

Engine 100 is a gasoline engine or a diesel engine. The engine controller 1 performs start control and stop control of the engine 100 and valve opening control of the throttle valve based on the target engine torque command. A flywheel 170 is provided on the engine output shaft.

The first clutch CL1 is a clutch that is interposed between the engine 100 and the motor 110 and can change the torque capacity continuously or stepwise. The “torque capacity” of the clutch is the magnitude of torque that can be transmitted by the clutch. Based on a target torque capacity (hereinafter referred to as “target first clutch torque capacity”) command of the first clutch CL1, the first clutch controller 5 uses the first clutch control oil pressure generated by the first clutch hydraulic unit 6 to Engagement / release (torque capacity) of the first clutch CL1 is controlled. As the first clutch CL1, for example, a dry single plate clutch whose torque capacity can be changed by a hydraulic actuator 14 having a piston 14a is used.

The motor 110 is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The motor controller 2 controls the motor 110 by applying the three-phase alternating current generated by the inverter 3 based on the target motor torque command and the target motor rotation speed command. The motor 110 is an electric motor that rotates by receiving power supplied from the battery 4, and as a generator that generates an electromotive force at both ends of the stator coil when the rotor receives rotational energy from the engine 100 or driving wheels. Function. The generated power is charged in the battery 4. Hereinafter, the state in which the motor 110 operates as an electric motor is referred to as “power running”, and the state in which the motor 110 operates as a generator is referred to as “regeneration”. The rotor of the motor 110 is connected to the transmission input shaft of the automatic transmission 120 via a damper.

The second clutch CL2 is a clutch that is interposed between the motor 110 and the

drive wheels

163 and 164 and can change the torque capacity continuously or stepwise. The AT controller 7 uses the control hydraulic pressure generated by the second clutch hydraulic unit 8 based on the target torque capacity (hereinafter referred to as “target second clutch torque capacity”) command of the second clutch CL2 to set the second clutch CL2. Controls fastening / release (torque capacity). As the second clutch CL2, for example, a wet multi-plate clutch or a wet multi-plate brake capable of changing the torque capacity by continuously controlling the oil flow rate and hydraulic pressure with a proportional solenoid is used. The first clutch hydraulic unit 6 and the second clutch hydraulic unit 8 are built in an AT hydraulic control valve unit 180 attached to the automatic transmission 120.

The automatic transmission 120 automatically switches, for example, stepped gear stages such as forward 7 speed / reverse 1 speed according to the vehicle speed, accelerator opening, and the like. The second clutch CL2 is not newly added as a dedicated clutch. Among the plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission 120, the second clutch CL2 is an optimum clutch or brake that is arranged on the torque transmission path. Selected. The output shaft of the automatic transmission 120 is connected to the left and

right drive wheels

163 and 164 via the propeller shaft 130, the differential 140, and the left and

right drive shafts

151 and 152.

The hybrid drive system includes an electric vehicle travel mode (hereinafter referred to as “EV mode”), a hybrid vehicle travel mode (hereinafter referred to as “HEV mode”), and a drive torque control travel mode (hereinafter referred to as “WSC mode”). .) And other driving modes.

“EV mode” is a mode in which the first clutch CL1 is disengaged and the vehicle travels only with the power of the motor 110.

“HEV mode” is a mode in which the first clutch CL1 is engaged and the vehicle is driven by the driving force of the engine 100 and the motor 110.

In the “WSC mode”, for example, when starting from the “EV mode” or starting from the “HEV mode”, the clutch transmission torque that causes the second clutch CL2 to be in the slip engagement state and passes through the second clutch CL2 is: In this mode, the vehicle starts while controlling the clutch torque capacity so that the required driving torque is determined according to the vehicle state and driver operation. “WSC” is an abbreviation of “Wet Start clutch”.

Next, the control system of the hybrid vehicle will be described.

The control system of the hybrid vehicle includes an engine, a motor, an automatic transmission, a brake, an

integrated controller

1, 2, 7, 9, 10, an inverter 3, a battery 4, a first clutch controller 5, a first clutch hydraulic unit 6, The second clutch hydraulic unit 8 is configured. The six

controllers

1, 2, 5, 7, 9, and 10 are connected via a CAN communication line 11 that can exchange information with each other.

The engine controller 1 inputs the engine rotation speed information from the engine rotation speed sensor 12, the target engine torque command from the integrated controller 10, and other necessary information. The engine controller 1 outputs a command for controlling the engine operating point (Ne, Te) to the throttle valve actuator or the like of the engine 100.

The motor controller 2 inputs information from the resolver 13 that detects the rotor rotation position of the motor 110, a target motor torque command and target motor rotation speed command from the integrated controller 10, and other necessary information. The motor controller 2 outputs a command for controlling the motor operating point (Nm, Tm) of the motor 110 to the inverter 3. Further, the motor controller 2 monitors the battery charge amount SOC that represents the charge capacity of the battery 4. The battery charge amount SOC information is used for control information of the motor 110 and is supplied to the integrated controller 10 via the CAN communication line 11.

The first clutch controller 5 inputs the sensor information from the first clutch stroke sensor 15, the target first clutch torque capacity command from the integrated controller 10, and other necessary information. The first clutch stroke sensor 15 detects the stroke position of the piston 14 a of the hydraulic actuator 14. The first clutch controller 5 outputs a command for controlling engagement / release (torque capacity) of the first clutch CL 1 to the first clutch hydraulic unit 6 in the AT hydraulic control valve unit 180.

AT controller 7 inputs information from accelerator opening sensor 16, vehicle speed sensor 17, and other sensors 18 (transmission input rotation speed sensor, inhibitor switch, etc.). The AT controller 7 searches for the optimum gear position based on the position where the operating point determined by the accelerator opening APO and the vehicle speed VSP exists on the shift map when traveling in the D range, and sends a control command for obtaining the searched gear position to the AT hydraulic control. Output to the valve unit 180. The AT hydraulic control valve unit 180 controls the engagement and release of each frictional engagement element (not shown). The shift map is a map in which an upshift line and a downshift line are written according to the accelerator opening and the vehicle speed.

The AT controller 7 performs the following second clutch control in addition to the automatic shift control. That is, when a target second clutch torque capacity command is input from the integrated controller 10, a command for controlling engagement / release (torque capacity) of the second clutch CL 2 is sent to the second clutch hydraulic unit 8 in the AT hydraulic control valve unit 180. Output.

The brake controller 9 inputs a wheel speed sensor 19 for detecting each wheel speed of the four wheels, sensor information from the brake stroke sensor 20, a regenerative cooperative control command from the integrated controller 10, and other necessary information. The brake controller 9 compensates for the shortage with the mechanical braking force (hydraulic braking force or motor braking force) when the regenerative braking force is insufficient with respect to the required braking force required from the brake stroke BS at the time of brake depression braking. In addition, regenerative cooperative brake control is performed.

The integrated controller 10 manages the energy consumption of the entire vehicle and has a function for running the vehicle with the highest efficiency. The integrated controller 10 inputs necessary information from the motor rotation speed sensor 21 that detects the motor rotation speed Nmot, other sensors / switches 22, and the CAN communication line 11. The integrated controller 10 outputs a target engine torque command, a target motor torque command and a target motor rotation speed command, a target first clutch torque capacity command, a target second clutch torque capacity command, and a regeneration cooperative control command.

FIG. 2 is a control block diagram showing calculation processing executed in the integrated controller 10. As shown in FIG. 2, the integrated controller 10 includes a target driving force calculation unit 31, a mode selection unit 32, a target charge / discharge power calculation unit 33, and an operating point command unit 34.

The target driving force calculation unit 31 calculates a target driving force tFo0 by searching a target driving force map from the accelerator opening APO and the vehicle speed VSP.

The mode selection unit 32 selects “EV mode” or “HEV mode” from the accelerator opening APO and the vehicle speed VSP using the EV / HEV mode selection map shown in FIG. 3, and selects the selected mode as the target travel mode. To do. However, if the battery charge SOC is equal to or less than the predetermined value, the “HEV mode” is forcibly set as the target travel mode. Further, when starting from the “EV mode” or “HEV mode”, the “WSC mode” is selected as the target travel mode until the vehicle speed VSP becomes the first set vehicle speed VSP1.

The operating point commanding unit 34 determines the operating point of the power train that combines the power source and the drive system, the target engine torque, the target motor torque (may be the target motor rotational speed), the target first clutch torque capacity, It is defined by the 2-clutch torque capacity and the target gear ratio.

In the hybrid vehicle, motor regeneration is performed during the coasting in the EV mode. However, if the motor regeneration is continued even after the battery 4 is fully charged by the motor regeneration, the battery 4 is overcharged and the battery 4 is deteriorated. There is a risk of inviting. However, if the motor regeneration is canceled to prevent overcharging of the battery 4, the deceleration braking force cannot be obtained.

Therefore, there is a reference example in which the desired deceleration braking force is obtained by using the engine brake together while preventing the battery 4 from being overcharged. This will be described with reference to FIG. FIG. 5 is a timing chart of a reference example showing control during coasting in the EV mode. “Coast” means that the vehicle is traveling inertia on a downhill or flat ground. For example, it can be determined that the vehicle is coasting when the accelerator opening APO is zero and the brake pedal is not depressed.

¡When the accelerator pedal is returned at t1 during traveling in the EV mode, the accelerator opening becomes zero at the timing of t2 and shifts to coasting in the EV mode. From the start of the shift to the coast in the EV mode, the motor regeneration is performed by maintaining the motor regeneration possible torque (Tmot) at a negative constant value (see the solid line in the third stage in FIG. 5). Since the battery 4 is charged by the motor regeneration, the battery charge amount SOC increases with a predetermined inclination from t2 (see the fourth stage in FIG. 5).

In the reference example, the third and fourth threshold values Vs3 and Vs4 are prepared in advance for the battery charge amount SOC. Among these, the third threshold value Vs3 is a charging upper limit value (indicating a fully charged state) in the EV mode, and is set to a value slightly lower than the first threshold value Vs1 that is the charging upper limit value in the HEV mode. Yes. On the other hand, the fourth threshold value Vs4 is a charging lower limit value in the EV mode, and is set to a value slightly higher than the second threshold value Vs2 that is the charging lower limit value in the HEV mode. For this reason, the motor regeneration possible torque (Tmot) is increased toward zero with a predetermined inclination from the timing t3 when the battery charge SOC reaches the third threshold value Vs3 due to the motor regeneration. The absolute value of the motor regeneration torque becomes small, and the slope of the battery charge amount SOC becomes gentler than t3. After the motor regenerative torque (Tmot) becomes zero at the timing of t4, the motor torque is increased with the same inclination, and is held at a positive constant value at the timing of t5. That is, from t4, the motor 110 is powered to reduce the battery charge amount SOC (see the solid line in the third stage in FIG. 5).

Meanwhile, the first clutch CL1 starts to be engaged at the timing of t3, and the first clutch CL1 is completely engaged at the time t4 (see the second stage in FIG. 5). In the fully engaged state of the first clutch CL1, the engine rotational speed Neng matches the transmission input shaft rotational speed Ntrin (= motor rotational speed Nmot), and the engine 100 is rotated by the drive system. That is, the engine friction torque acts on the drive system as an engine brake.

In the third row of FIG. 5, the first clutch torque capacity (CL1 torque capacity) is shown superimposed on a two-dot chain line. The negative first clutch torque capacity indicates that the engine friction torque is acting on the drive system via the engaged first clutch CL1. In this case, after t4, the difference between the absolute value of the engine friction torque and the motor regenerative torque (Tmot) becomes the vehicle braking torque. Therefore, the vehicle braking force can be obtained by determining the target motor torque during power running so that the motor regenerative torque (Tmot) does not exceed the absolute value of the engine friction torque.

By increasing the motor regenerative torque (Tmot) to zero from t3, the slope of the battery charge SOC becomes gentler than before t3, and the battery charge SOC is reduced at t4 when the first clutch CL1 is completely engaged. Peak value. The battery charge amount SOC then gradually decreases until t5, and then decreases with a steeper slope than before t5 (see the fourth stage in FIG. 5).

The battery charge SOC reaches the fourth threshold value Vs4 at the timing of t6 due to the decrease in the battery charge SOC. At t6, the target motor torque (power running torque) is decreased with a predetermined slope so that the battery charge SOC does not decrease any more. When the target motor torque Tmot (power running torque) becomes zero at the timing of t7, the inclination of the torque is relaxed and the torque is held at a negative constant value at the timing of t8. That is, from t7, motor regeneration possible torque is applied again to perform motor regeneration, and the battery charge amount SOC is increased (see the fourth stage in FIG. 5).

On the other hand, the first clutch torque capacity is increased toward zero from t7 and is made to coincide with the target motor torque Tmot at timing t8.

As described above, in the reference example, by driving the motor 110, the first clutch is engaged while preventing overcharging of the battery 4, and the difference between the absolute value of the engine friction torque and the motor regenerative torque (Tmot). Is used as a vehicle braking torque to decelerate the vehicle.

However, the battery charge SOC changes after t4. The engine rotational speed Neng (= transmission input shaft rotational speed Ntrin) hunts according to the change in the battery charge amount SOC, and the vehicle braking force slightly varies when the motor 110 transitions between regeneration and power running. (See the portion surrounded by the dotted line at the bottom of FIG. 5).

Therefore, in the present embodiment, the following operation is executed in order to cooperatively control the motor regeneration possible torque, the target first clutch torque capacity, and the target gear ratio with respect to the driver request vehicle braking force.

<1> When the battery 4 is fully charged during the coasting in the EV mode and the motor cannot be regenerated, the resulting vehicle braking force due to engine friction after the first clutch CL1 is completely engaged becomes the target vehicle braking force. A target gear ratio is instructed in a feed-forward manner. This target gear ratio instructed in a feedforward manner is referred to as “feedforward target gear ratio”.

<2> When the battery 4 is fully charged, the motor regenerative torque is increased toward zero. At this time, the first clutch CL1 is engaged without changing the vehicle braking force by instructing the target first clutch torque capacity (hydraulic pressure) to continue to satisfy the target vehicle braking force as the motor regenerative torque increases. I do.

<3> By increasing the motor regenerative torque toward zero, the motor regenerative torque becomes zero. At this time, the target motor torque is limited to zero so as to stop at the end of regeneration without shifting from motor regeneration to motor power running.

The cooperative control of the target motor torque (motor regeneration possible torque), the target first clutch torque capacity, and the target gear ratio will be described with reference to FIG. FIG. 6 shows how the accelerator opening APO, the motor rotation speed Nmot, the engine rotation speed Neng, the target motor torque Tmot, the target first clutch torque capacity, the battery charge amount SOC, and the like change during the coasting in the EV mode. Is shown. Here, it is assumed that the hybrid vehicle is operated in the same manner as in the reference example. For comparison, the case of the reference example is shown by overlapping with a thin line.

In the present embodiment, since the feedforward target gear ratio of <1> is instructed to the automatic transmission 120 from the timing t3 when the battery charge SOC reaches the third threshold value Vs3, the inclination of the motor rotation speed is a reference example. It becomes more gradual and settles to a constant value at the timing of t4. Similarly, since the target first clutch torque capacity (hydraulic pressure) of the above <2> is instructed to the first clutch CL1 from t3, the inclination of the first clutch torque capacity to the negative side is more gradual than that of the reference example. It settles to a negative constant value at the timing. At t4, the first clutch is completely engaged, whereby engine friction torque acts on the vehicle and engine braking is obtained.

Similarly, when the target motor torque Tmot (= regenerative torque) is increased toward zero from t3, the target motor torque Tmot reaches zero at the timing of t4. At this time, since the target motor torque Tmot is maintained at zero in the above <3>, the battery charge amount SOC is kept constant from t4.

In this embodiment, the battery charge amount SOC is not changed while obtaining the target vehicle braking force by giving the feedforward target gear ratio. As a result, as in the reference example, the automatic transmission 120 is downshifted too much and the engine brake becomes too effective, and it is not necessary to perform motor powering to alleviate this effect. As a result, since the state transition in which the motor 110 repeats power generation and charging does not occur, the target vehicle braking force is reduced without hunting the engine rotational speed Neng (= transmission input shaft rotational speed Ntrin) and unnecessary charging / discharging. realizable.

2 will be described with reference to the control block diagram of FIG.

In FIG. 7, the power generation torque calculation unit 41 calculates a power generation torque Tgen [Nm] by searching a predetermined table (power generation torque table) from the current motor rotation speed Nmot. The “power generation torque” is torque that can be regenerated at the current motor rotation speed Nmot. The power generation torque Tgen is given as a negative value. This is because the motor torque is defined as a positive value during power running and the motor torque as a negative value during regeneration.

The maximum value selection unit 42 compares the power generation torque Tgen with the motor regenerative torque [Nm] from the motor regenerative torque calculation unit 65, and selects and outputs the larger side. Since the two torques are negative values, the smaller negative value is selected.

“The motor regenerative torque” is the maximum torque that the motor 110 can regenerate. The calculation method of the motor regenerative torque that is performed by the motor regenerative torque calculation unit 65 is omitted. In brief, the motor regeneration possible torque is an upper limit value determined by various requirements such as the battery charge amount SOC, the state of the inverter 3, and the torque required when starting the engine. For example, the maximum torque that can be regenerated by the motor 110 is obtained based on the battery charge amount SOC and the state of the inverter 3, and the value obtained by subtracting the torque necessary for engine start from the obtained torque is set as the motor regenerative torque. Therefore, the difference from the power generation torque Tgen is as follows. That is, the power generation torque Tgen is the maximum regenerative torque (almost determined if the maximum kW is determined). On the other hand, the motor regenerative torque is a value having a meaning such as a limit value determined in real time from various requirements of the system.

Specifically, during coasting in the EV mode, the motor regeneration possible torque is a constant negative value because of motor regeneration. When the battery charge amount SOC reaches the third threshold value Vs3, the motor regeneration possible torque is negative. It goes from zero to zero. Since the absolute value of the motor regenerative torque calculated in this way during the coasting in the EV mode is smaller than the absolute value of the power generation torque, the maximum value selection unit 42 does the motor regeneration during the coasting in the EV mode. Output possible torque.

The maximum value limiter 43 limits the negative output from the maximum value selector 42 to zero at the maximum. Referring to FIG. 6, during the period from t2 to t3, the motor regeneration possible torque is given as a negative value, and the battery charge amount SOC increases. Since the motor regenerative torque increases from t3 toward zero, the slope of the battery charge amount SO becomes gentler than before t3. The motor regeneration possible torque reaches zero at t4, and the target motor torque is maintained at zero after t4. That is, the motor regenerative torque is maintained at zero after t4 due to the function of the maximum value limiting unit 43.

Referring back to FIG. The engine friction torque calculation unit 44 calculates an engine friction torque Teng by searching a predetermined table (engine friction torque table) from the engine rotation speed Neng.

The feedforward target gear ratio calculation unit 45 calculates a feedforward target gear ratio Rff by searching a predetermined table (target gear ratio table) from the vehicle speed VSP.

Here, how to set the feedforward target gear ratio table will be described. First, a driver requested vehicle braking force table in which a driver requested vehicle braking force Fdrv corresponding to the vehicle speed VSP is defined as shown in FIG. Here, the vehicle braking force Fdrv is a driving force converted to a drive shaft axis. The vehicle braking force Fdrv is basically a negative value, but a positive value is given in a region where the vehicle speed VSP is low. This is because creep torque is applied in a region where the vehicle speed VSP is low.

On the other hand, the relationship between the engine rotational speed Neng and the engine friction torque Teng is defined as in the engine friction torque table shown in FIG. Further, from the following equations (1) and (2), the relationship of the vehicle braking force Fdrvf generated by the engine friction with respect to the vehicle speed VSP can be defined for each gear ratio RATIO as shown in the graph of FIG. 9B. .
Fdrvf [N] = Teng [Nm] × RATIO × final reduction ratio / dynamic rotation radius [m]
... (1)
VSP [km / h] = Neng [rpm] / (RATIO × final reduction ratio)
× Dynamic rotation radius [m] × 2π × 60/1000 (2)

Here, the final reduction ratio and dynamic rotation radius in the equations (1) and (2) are constant values.

As shown in FIG. 10 (A), when the graph of FIG. 9 (B) is superimposed on the driver requested vehicle braking force table of FIG. 8, the relationship between the intersections of the respective graphs is extracted (FIG. 10 (B)). Thus, a gear ratio table defining the relationship between the vehicle speed VSP and the gear ratio RATIO (speed stage) for outputting the driver requested vehicle braking force by the engine friction torque Teng is obtained. By setting the transmission gear ratio RATIO at this time as the feedforward target transmission gear ratio Rff, the feedforward target transmission gear ratio table can be set.

In other words, the feedforward target gear ratio calculation unit 45 calculates the driving braking force determined from the engine friction torque Teng and the driver requested vehicle braking force Fdrv when the battery 4 is not fully regenerated because the battery 4 is fully charged. The target gear ratio is calculated in a feed-forward manner. By providing the feedforward target speed ratio Rff thus determined to the automatic transmission 120, it is possible to avoid excessive deceleration force itself after the shift that has occurred in the reference example when full regeneration cannot be performed. Can be avoided.

The full regeneration possibility determination unit 50 includes a driver request vehicle braking force calculation unit 46, a vehicle braking force calculation unit 51, absolute

value calculation units

52 and 53, and a comparison unit 54.

The vehicle braking force calculation unit 51 calculates an actual vehicle braking force from the motor regenerative torque and the current gear ratio of the automatic transmission according to the following equation.
Actual vehicle braking force = Motor regenerative torque x Current gear ratio x Proportional constant (3)

(3) The actual vehicle braking force of equation (3) is also the driving force converted to the drive shaft axis.

The absolute value calculation unit 52 calculates the absolute value of the actual vehicle braking force, and the absolute value calculation unit 53 calculates the absolute value of the driver request vehicle braking force. The comparison unit 54 compares the absolute value calculated by the absolute value calculation unit 52 with the absolute value calculated by the absolute value calculation unit 53. The driver requested vehicle braking force calculation unit 46 determines the magnitude of the driver requested vehicle braking force using the driver requested vehicle braking force table shown in FIG. When the absolute value of the actual vehicle braking force is less than the absolute value of the driver requested vehicle braking force Fdrv, it is determined that the vehicle braking force is less than the requirement, that is, full regeneration is possible, and the full regeneration possible flag = 1. And In other cases, the full regeneration enable flag = 0. When the absolute value of the actual vehicle braking force is less than the absolute value of the driver requested vehicle braking force, there is no restriction on motor regeneration, that is, when the driver requested vehicle braking force can be achieved only by motor regeneration. is there.

The selection unit 55 selects one of the two gear ratios using the value of the full regeneration enable flag as a selection instruction signal. That is, when the full regeneration enable flag = 1, the coast target speed ratio at full regeneration is selected. When the full regeneration enable flag = 0, the feedforward target speed ratio Rff is selected, and the selected speed ratio is set as the target speed ratio. Output.

Note that the full regeneration coast target speed ratio (the full regeneration target speed ratio during the coast) is outside the scope of the present invention, and therefore the calculation method of the full regeneration coast target speed ratio is omitted.

The target first clutch torque capacity calculating unit 56 includes an engine friction torque calculating unit 44, a dividing unit 57, an absolute value calculating unit 58, a subtracting unit 59, a limiting unit 60, an absolute value calculating unit 61, and a multiplying unit 62.

The target first clutch torque capacity calculation unit 56 calculates the target first clutch torque capacity Ccl1 by the following equation.
Ccl1 = | Teng | × (1- | Motor regeneration possible torque / Tgen |) (4)

The engine friction torque calculation unit 44 determines the magnitude of the engine friction torque Teng using the engine friction torque table shown in FIG.

Here, the first clutch torque capacity ratio is a value given by the following equation.
First clutch torque capacity ratio = 1− | Motor regenerative torque / Tgen | (5)

The first clutch torque capacity ratio is 0% when full regeneration is possible and 100% when full regeneration is impossible. When the first clutch torque capacity ratio is not zero, the target first clutch torque capacity changes according to the motor regeneration possible ratio (| motor regeneration possible torque / Tgen |), and when the motor regeneration cannot be performed at all, the first clutch CL1 Completely concluded.

Referring to FIG. 6, from t2 to t3, the motor regenerative torque is equal to the power generation torque Tgen, the first clutch torque capacity ratio is 0% from the equation (5), and the target first clutch torque capacity is from the equation (4). Zero. Therefore, the first clutch torque capacity (CL1 capacity) becomes zero from t2 to t3, and the first clutch CL1 is in a disconnected state.

When the motor regenerative torque becomes smaller in absolute value from t3, the first clutch torque capacity ratio becomes larger than 0% from the equation (5). When the motor regenerative torque becomes zero at t4, the first clutch torque capacity ratio becomes 100% from the equation (5). That is, the first clutch CL1 is completely engaged at t4. In the fully engaged state of the first clutch CL1, the engine 100 is rotated by the drive system, so that the engine rotational speed Neng is zero at t3, but rises and becomes equal to the motor rotational speed Nmot at the timing of t4. It is maintained at a constant value after t4. When the engine speed Neng changes from zero to a positive value during the period from t3 to t4, the engine friction torque Teng changes from zero to a negative value.

The flowchart of FIG. 11 shows the flow of the control described using the control block of FIG. 7, that is, the control for calculating the target motor torque, the target gear ratio, and the target first clutch torque capacity. The process of the flowchart shown in FIG. 11 is executed at regular time intervals (for example, every 10 ms).

In step S1, the driver request vehicle braking force Fdrv is calculated from the vehicle speed VSP.

In step S2, it is determined whether or not the vehicle is in coasting in the EV mode and the vehicle speed VSP exceeds the first predetermined vehicle speed V1. Here, it is determined that the vehicle is coasting when the accelerator opening APO = 0 and the brake pedal is not depressed (brake stroke BS = 0). Even during the coasting in the EV mode, in the region where the vehicle speed VSP is equal to or lower than the first predetermined vehicle speed V1, the current process is terminated as it is (the control of this embodiment is not performed). This is because, for example, as a system operation requirement or a fuel consumption target, there is a request to basically run in the EV mode at the first predetermined vehicle speed V1 or less. That is, in a vehicle speed range that is equal to or lower than the first predetermined vehicle speed V1, the fuel efficiency is better when the vehicle is driven with inertia while the first clutch CL1 is in the non-engaged state than the engine brake by engaging the first clutch CL1. There is.

On the other hand, when coasting in the EV mode and the vehicle speed VSP exceeds the first predetermined vehicle speed V1, the process proceeds to step S3 and subsequent steps in order to perform the control of the present embodiment. In step S3, it is determined whether or not the battery charge amount SOC is less than the third threshold value Vs3 and the driver-requested vehicle braking force Fdrv can be achieved only by full regeneration. Here, the determination as to whether or not the driver-required vehicle braking force Fdrv can be achieved only by full regeneration is performed by the full regeneration possibility determination unit 50 of FIG. Said 3rd threshold value Vs3 is a charge upper limit in EV mode (refer FIG. 5, FIG. 6).

If it is determined in step S3 that the battery charge SOC is less than the third threshold value Vs3 and the driver-requested vehicle braking force Fdrv can be achieved only by full regeneration, the process proceeds to steps S4 to S6. The processes in steps S4 to S6 are performed in the period from t2 to t3 in FIG.

In step S4, the motor regeneration possible torque is set as the target motor torque. In step S5, the full regeneration coast target speed ratio (see FIG. 7), which is the normal target speed ratio in the EV mode, is calculated, and the calculated full regeneration coast target speed ratio is set as the target speed ratio.

In step S6, the target first clutch torque capacity = 0. That is, when the battery charge amount SOC is less than the third threshold value Vs3 and the driver-requested vehicle braking force Fdrv can be achieved only by full regeneration, the EV mode remains.

If it is determined in step S3 that the battery charge SOC is greater than or equal to the third threshold value Vs3, or if the driver-requested vehicle braking force Fdrv cannot be achieved only by full regeneration, the process proceeds to step S7. In step S7, it is determined whether or not the motor regeneration possible torque gradual reduction processing mode is set. For example, when the battery charge amount SOC becomes equal to or greater than the third threshold value Vs3, it is determined that the motor regeneration possible torque gradual reduction processing mode has been entered. When it is in the motor regeneration possible torque gradual reduction processing mode, the process proceeds to steps S8 to S10. The processes in steps S8 to S10 are performed in the period from t3 to t4 in FIG.

In step S8, the motor regeneration possible torque is gradually reduced. In the gradual reduction process of the motor regenerative torque, the motor regenerative torque is gradually increased to zero (see the period from t3 to t4 in FIG. 6). Then, the gradual reduction value of the motor regenerative torque is set as the target motor torque. In step S9, the feedforward target speed ratio Rff is calculated using the feedforward target speed ratio table, and the calculated feedforward target speed ratio Rff is set as the target speed ratio.

In step S10, the target first clutch torque capacity is calculated from the above equation (4). As a result, the EV mode is shifted to the HEV mode.

When the motor regeneration possible torque gradual reduction processing mode is not set in step S7, the process proceeds to steps S11 to S13. The processes in steps S11 to S13 are performed in a period after t4 in FIG.

In step S11, the target motor torque is set to zero (no regeneration or power running). In step S12, the feedforward target speed ratio Rff is calculated using the above-mentioned feedforward target speed ratio table, and the calculated feedforward target speed ratio Rff is set as the target speed ratio.

In step S13, the torque capacity when the first clutch is completely engaged is calculated as the target first clutch torque capacity. That is, the HEV mode is set.

In another flow (not shown), the target motor torque, target gear ratio, and target first clutch torque capacity calculated in this way are indicated.

Here, the function and effect of this embodiment will be described.

The hybrid vehicle control apparatus according to the present embodiment includes an engine 100, a motor 110 (motor generator), a first clutch CL1 that intermittently connects between them, and an automatic transmission 120 (transmission). When the CL1 is engaged, the driving force of the engine 100 and the motor GM is transmitted in the HEV mode to transmit the driving force to the input shaft of the automatic transmission 120. When the first clutch CL1 is released, the driving force of only the motor GM is used as the input shaft of the transmission. EV mode travel is transmitted to the vehicle. In this hybrid vehicle control device, the accelerator release and charge state determination means for determining whether the battery is being coasted (accelerator being released) and the battery charge amount SOC is in a fully charged state (predetermined amount or more), engine friction An engine friction torque calculating unit 44 (engine friction torque calculating unit) that calculates torque, a motor regenerative torque calculating unit 65 (motor regenerative torque calculating unit) that calculates torque that can be regenerated by the motor 110, and this calculation. Motor controller 2 (motor torque control means) for controlling the motor torque so as to obtain a motor regenerative torque, coasting in EV mode (accelerator being released), and the battery charge amount SOC being fully charged (predetermined amount or more) When it is determined that the vehicle is in the driver's request vehicle braking force Fdrv Based on the driver request vehicle braking force calculation unit 46 (target vehicle deceleration force calculation means) that calculates the target vehicle deceleration force) and the calculated driver request vehicle braking force Fdrv and the calculated engine friction torque, A feedforward target speed ratio calculating unit 45 (target speed ratio calculating means) for calculating a speed ratio Rff (target speed ratio) and the speed ratio of the automatic transmission 120 so as to obtain the feedforward target speed ratio Rff. The target first clutch torque based on the AT controller 7 (speed ratio control means) and the calculated driver request vehicle braking force Fdrv and the calculated motor regenerative torque when the speed ratio is controlled by the controller 7 Target first clutch torque capacity calculation unit 56 for calculating capacity (target clutch engagement capacity) A target clutch engagement capacity calculating means), and a first clutch controller 5 for controlling the torque capacity of the first clutch as the target first clutch torque capacity is obtained (clutch connection capacity control means).

According to the present embodiment, when the EV mode is coasting (accelerator being released) and the battery charge amount is in a fully charged state (a predetermined amount or more), the motor regeneration possible torque, the target first clutch torque capacity, Since the feedforward target gear ratio is cooperatively controlled, it is not necessary to downshift the automatic transmission 120 as in the conventional device and to power the motor GM to achieve engine braking. As a result, it is possible to prevent hunting of the engine speed and to realize a driver-requested vehicle braking force (target vehicle deceleration force).

According to the present embodiment, the feedforward target gear ratio (target gear ratio) is set so that the driver requested vehicle braking force (target vehicle deceleration force) is generated by the vehicle deceleration force generated by the engine friction torque when the first clutch CL1 is fully engaged. Ratio) is calculated, it is possible to obtain a feeling of vehicle deceleration without a sense of incongruity.

According to this embodiment, the motor controller 2 (motor generator torque control means) maintains the motor regenerative torque at zero when the first clutch controller 5 (clutch engagement capacity control means) fully engages the first clutch CL1. Therefore, useless charging / discharging can be eliminated.

(Second Embodiment)
The flowchart of FIG. 12 shows the flow of processing for calculating the target motor torque, the target gear ratio, and the target first clutch torque capacity of the second embodiment, and replaces FIG. 11 of the first embodiment. The same number is attached | subjected to the same part as FIG. 11 of 1st Embodiment. The process of the flowchart shown in FIG. 12 is also executed at regular time intervals (for example, every 10 ms).

In the first embodiment, when the battery is fully charged (predetermined amount or more) during the coasting in EV mode (when the accelerator is released), the regenerative torque, the target first clutch torque capacity, The target gear ratio was controlled cooperatively. In the second embodiment, when the battery is in a fully charged state (a predetermined amount or more) during the coasting in the HEV mode, the regenerative torque, the target first clutch torque capacity, and the target gear ratio are coordinated with the driver request vehicle braking force. Control.

In the following, processing different from the first embodiment will be mainly described. In step S21, it is determined whether or not the vehicle speed VSP exceeds the second predetermined vehicle speed V2 during the coasting in the HEV mode. Here, it is determined that the vehicle is coasting when the accelerator opening APO = 0 and the brake pedal is not depressed (brake stroke BS = 0). Even during the coasting in the HEV mode, in the region where the vehicle speed VSP is equal to or lower than the second predetermined vehicle speed V2, the current process is terminated as it is (the control of the second embodiment is not performed). This is because, for example, as a system operation requirement or a fuel consumption target, there is a request to basically run in the HEV mode at the second predetermined vehicle speed V2 or lower. The second predetermined vehicle speed V2 may be the same as the first predetermined vehicle speed 1.

On the other hand, during the coasting in the HEV mode and when the vehicle speed VSP exceeds the second predetermined vehicle speed V2, the process proceeds to step S22 and subsequent steps in order to perform the control of the second embodiment. In step S22, the battery charge amount SOC is compared with the third threshold value Vs3, and in step S23, it is determined whether or not the driver-requested vehicle braking force can be achieved only by full regeneration. In steps S22 and S23, when the battery charge SOC is less than the third threshold value Vs3 and the driver-requested vehicle braking force can be achieved only by full regeneration, the process proceeds to steps S24, S5, and S6.

In step S24, the target motor torque corresponding to the driver request vehicle braking force Fdrv is calculated, and the calculated target motor torque corresponding to the driver request vehicle braking force Fdrv is set as the target motor torque. In step S5, the full regeneration coast target speed ratio (see FIG. 7), which is the normal target speed ratio in the EV mode, is calculated, and the calculated full regeneration coast target speed ratio is set as the target speed ratio.

In step S6, the target first clutch torque capacity = 0. This shifts to the EV mode.

If the charge amount SOC is less than the third threshold value Vs3 in step S22, but it is determined in step S23 that the driver-required vehicle braking force cannot be achieved only by full regeneration, the process proceeds to step S4, and the motor regeneration possible torque is set as the target motor torque. .

In step S25, the target gear ratio at the time of full regeneration in the HEV mode is calculated, and the calculated target gear ratio at the time of full regeneration is set as the target gear ratio. Here, the reason for calculating the target gear ratio during full regeneration in the HEV mode when the driver-required vehicle braking force cannot be achieved only by full regeneration will be described. When the driver-required vehicle braking force can be achieved only by full regeneration, the driver-required vehicle braking force can be achieved by only full regeneration in the EV mode (when the first clutch CL1 is released). On the other hand, when the driver-required vehicle braking force cannot be achieved only by full regeneration, the driver-required vehicle braking force must be achieved only by full regeneration in the HEV mode (when the first clutch CL1 is engaged). The difference in gear ratio between when the driver-requested vehicle braking force can be achieved only by full regeneration in the EV mode and when the driver-requested vehicle braking force cannot be achieved only by full regeneration in the HEV mode is that the engine 100 is driven by the first clutch CL1. The difference is whether or not it is fastened. Even when the first clutch CL1 is engaged and when it is not engaged, the engine braking force changes even when the speed ratio is the same. The purpose is to obtain the driver requested vehicle braking force Fdrv regardless of whether the first clutch CL1 is engaged or disengaged. Therefore, the driver request depends on whether the first clutch CL1 is disengaged or engaged. There is a difference in the gear ratio for achieving the vehicle braking force Fdrv. Therefore, a gear ratio that satisfies the driver-requested vehicle braking force Fdrv by full regeneration in the HEV mode is calculated. The target gear ratio during full regeneration in the HEV mode is calculated based on the driver requested vehicle braking force Fdrv, motor regeneration possible torque, and engine friction torque.

In step S26, the torque capacity when the first clutch CL1 is completely engaged is calculated as the target first clutch torque capacity. That is, the HEV mode is maintained.

If it is determined in step S22 that the charge amount SOC is greater than or equal to the third threshold value Vs3, the process proceeds to step S7, where it is determined whether or not the motor regeneration torque gradual reduction processing mode is set. For example, when the battery charge amount SOC becomes equal to or greater than the third threshold value Vs3, it is determined that the motor regeneration torque gradual reduction processing mode has been entered. When it is in the motor regenerative torque gradual reduction processing mode, the process proceeds to steps S8, S9, and S27.

In step S8, the motor regeneration possible torque is gradually reduced. In the gradual reduction process of the motor regenerative torque, the motor regenerative torque is gradually increased to zero (see the period from t3 to t4 in FIG. 6). Then, the gradual reduction value of the motor regenerative torque is set as the target motor torque.

In step S9, the feedforward target speed ratio Rff is calculated using the above-mentioned feedforward target speed ratio table, and the calculated feedforward target speed ratio Rff is set as the target speed ratio.

In step S27, the torque capacity when the first clutch is completely engaged is calculated as the target first clutch torque capacity. That is, the HEV mode is maintained.

Thus, according to the second embodiment, when the HEV mode is coasting (accelerator being released) and the battery charge amount is in a fully charged state (a predetermined amount or more), the motor regeneration possible torque, the target first Since the one-clutch torque capacity and the target gear ratio are coordinately controlled, it is not necessary to downshift the automatic transmission 120 too much and run the motor GM to achieve engine braking as in the reference example. As a result, it is possible to prevent hunting of the engine speed and to realize the driver-requested vehicle braking force.

In a hybrid vehicle, the vehicle braking force when the brake pedal is not depressed can be generated by the motor regeneration and the engine brake. Therefore, the hybrid vehicle tries to generate a vehicle braking force equivalent to a vehicle driven only by the engine. Then, the vehicle deceleration torque during the coast shared by the engine brake can be smaller than that of the vehicle driven only by the engine. Therefore, in the hybrid vehicle, in order to generate the engine brake, the engine speed is controlled to be smaller than that of the vehicle driven only by the engine. Therefore, in order to prevent the driver from feeling uncomfortable due to an engine rotation feeling different from that of a vehicle driven only by an engine, it is necessary to cause engine rotation during vehicle braking that can occur in a vehicle driven only by the engine. is there.

For this reason, the engine rotational speed when the target vehicle deceleration force is obtained during coasting with a vehicle driven only by the engine is determined in advance as the target rotational speed, and the target vehicle deceleration force is set based on the target rotational speed. To do. As a result, even in a hybrid vehicle, it is possible to obtain the same engine rotation feeling as during coasting in a vehicle driven only by an engine.

The present invention is not limited to the embodiment described above.

This application claims priority based on Japanese Patent Application No. 2012-087055 filed with the Japan Patent Office on April 6, 2012, the entire contents of which are incorporated herein by reference.

Claims

An HEV mode running that includes an engine, a motor generator, a clutch that intermittently connects between them, and a transmission, and that transmits the driving force of the engine and the motor generator to the input shaft of the transmission when the clutch is engaged. In the hybrid vehicle control device that is traveling in the EV mode in which the driving force of only the motor generator is transmitted to the input shaft of the transmission when the clutch is released,
Accelerator release determination means for determining whether or not the accelerator pedal is being released;
Charge state determination means for determining whether or not a charge amount of a battery that exchanges power with the motor generator is a predetermined amount or more;
Engine friction torque calculating means for calculating the friction torque of the engine;
Motor generator regenerative torque calculating means for calculating torque that can be regenerated by the motor generator;
Motor generator torque control means for controlling the torque of the motor generator so as to obtain the calculated motor generator regenerative torque;
In the EV mode or HEV mode, when it is determined that the accelerator pedal is released and the battery charge amount is greater than or equal to a predetermined amount, the transmission gear ratio is adjusted so that a target gear ratio according to the vehicle speed is obtained. Gear ratio control means for controlling;
Target clutch engagement capacity calculation means for calculating a target clutch engagement capacity based on the calculated engine friction torque and the calculated motor generator regenerative torque when the transmission ratio is controlled by the transmission ratio control means. When,
A control device for a hybrid vehicle, comprising: clutch engagement capacity control means for controlling the engagement capacity of the clutch so that the calculated target clutch engagement capacity is obtained.
In the hybrid vehicle control device according to claim 1,
A hybrid vehicle control device further comprising target gear ratio calculation means for calculating the target gear ratio such that a target vehicle deceleration force is generated by a vehicle deceleration force generated by an engine friction torque when the clutch is completely engaged.
In the hybrid vehicle control device according to claim 1 or 2,
The engine rotational speed when the target vehicle deceleration force is obtained during release of the accelerator pedal in a vehicle driven only by the engine is determined in advance as the target rotational speed, and the target vehicle deceleration force is set based on the target rotational speed. A control device for a hybrid vehicle.
In the control apparatus of the hybrid vehicle as described in any one of Claims 1-3,
The motor generator torque control means is a hybrid vehicle control device that maintains the motor generator regenerative torque at zero when the clutch engagement capacity control means fully engages the clutch.
An HEV mode running that includes an engine, a motor generator, a clutch that intermittently connects between them, and a transmission, and that transmits the driving force of the engine and the motor generator to the input shaft of the transmission when the clutch is engaged. In the hybrid vehicle control method for EV mode running in which the driving force of only the motor generator is transmitted to the input shaft of the transmission when the clutch is released,
Determine whether the accelerator pedal is being released,
Determining whether or not a charge amount of a battery that exchanges power with the motor generator is a predetermined amount or more;
Calculating the friction torque of the engine,
Calculate the torque that the motor generator can regenerate,
Control the torque of the motor generator so that the calculated motor generator regenerative torque is obtained,
In the EV mode or HEV mode, when it is determined that the accelerator pedal is released and the battery charge amount is greater than or equal to a predetermined amount, the transmission gear ratio is adjusted so that a target gear ratio according to the vehicle speed is obtained. Control
When the gear ratio is controlled, a target clutch engagement capacity is calculated based on the calculated engine friction torque and the calculated motor generator regenerative torque,
Controlling the clutch engagement capacity so as to obtain the calculated target clutch engagement capacity;
Control method of hybrid vehicle.