JP2000278816A - Transmission control device for electric vehicle - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a shift control device for an electric vehicle, which can surely perform a shift even when traveling on a steep uphill or downhill road. A change amount of a target motor speed in a neutral state is calculated based on an output (actual vehicle speed) of a vehicle speed detector and a gear ratio of the target speed, and a shift speed switching time of the speed and the target motor speed are calculated. A correction value is calculated on the basis of the change amount of the target speed, and a target motor speed after shifting is calculated based on the output of the vehicle speed detector and the gear ratio of the target shift speed. Then, the target motor rotation speed is corrected by the correction value, the motor output is controlled using the corrected target motor rotation speed as a target value, and the actual motor rotation speed is synchronized with the target motor rotation speed. When the actual motor speed and the corrected target motor speed are synchronized, the speed of the transmission is switched to the target speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shift control device for an electric vehicle.

[0002]

2. Description of the Related Art An electric vehicle includes an electric vehicle (EV) having a traction motor, a traction motor and a power generator or a power generator.
There is a series-type or parallel-type hybrid electric vehicle having an engine for both running and running. A technology in which these electric vehicles are provided with a transmission having a plurality of speed change gears is known from Japanese Patent Application Laid-Open No. 8-168110. Have been.
This publication discloses a shift control method for an electric vehicle that can smoothly switch gears while depressing an accelerator pedal.

[0003]

As a transmission for these electric vehicles, a mechanical transmission having a plurality of speed-change gears is provided with a hydraulic actuator for driving a shift fork, and further provided with a synchromesh mechanism and a clutch. Alternatively, it is conceivable to control the rotation of the traveling motor itself to synchronize the motor rotation speed with the vehicle speed, thereby enabling smooth shifting.

[0004] The flow of shift control using such a mechanical transmission will be briefly described. For example, when a transmission has two shift speeds, high (H) and low (L), a driver operates a shift operating device. When the gearshift operation device outputs a switching command signal to H or L, the torque of the traveling motor is reduced to zero regardless of the amount of depression of the accelerator pedal, and then the shift fork drive hydraulic actuator is operated. By turning off the shift fork driving hydraulic pressure of the currently connected gear in step 2, the gear of the gear is removed to bring the transmission into a neutral state.

After that, the actual vehicle speed and the target gear (H or L)
The output (torque) of the traveling motor is controlled using the target motor rotation speed obtained from the above as a target value. Next, when the actual motor speed and the target motor speed are synchronized, the shift speed of the transmission is connected to the target shift speed by the shift fork drive hydraulic actuator.

However, since the vehicle speed change of the operation delay time from when the synchronization condition is satisfied and the shift fork drive hydraulic pressure ON command is output to when the gear of the target shift stage is actually connected is not considered, When the vehicle is traveling on a steep ascending or descending slope, the difference between the actual vehicle speed and the actual motor speed at the time when the gear of the target shift stage is connected is caused by the actual vehicle speed change of the operation delay time. As a result, there is a possibility that gear noise may occur or gear connection may not be possible.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a shift control device for an electric vehicle which can surely perform a shift even when traveling on a steep uphill or downhill road. I do.

[0008]

According to the present invention, there is provided a shift control apparatus for an electric vehicle which solves the above-mentioned problems. The shift speed of a transmission interposed between a traveling motor and drive wheels is output by a shift command means. A shift control device for an electric vehicle that switches to a target shift speed via a neutral state based on a vehicle speed detecting means for detecting a vehicle speed of the vehicle; and an output of the vehicle speed detecting means and a gear ratio of the target shift speed. A change amount calculating means for calculating a change amount of the target motor speed in the neutral state; a correction value calculating means for calculating a correction value based on a shift speed switching time of the shift speed and an output of the change amount calculating means; Target motor speed calculating means for calculating a target motor speed after shifting based on the output of the vehicle speed detecting means and the gear ratio of the target shift speed, and the target motor speed based on the correction value Target motor rotation speed correcting means for correcting, motor control means for controlling motor output using the corrected corrected target motor rotation speed as a target value, and when the actual motor rotation speed and the corrected target motor rotation speed are synchronized. And a shift control means for switching a shift speed of the transmission to the target shift speed.

Therefore, according to this shift control device, even when the actual vehicle speed changes at the time of gear change of the gear stage because the vehicle is traveling on a steep uphill or downhill, the actual motor speed is not changed to the target speed. Since the number of revolutions corresponds to the actual vehicle speed at the moment when the gears of the gears mesh with each other, the gears of the target gear are smoothly connected.

[0010]

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

FIG. 1 is a block diagram of a hybrid electric vehicle provided with a shift control device according to an embodiment of the present invention.
Is a flowchart showing the overall processing of the shift control device, and FIG. 3 is a flowchart showing the content of the synchronous control of the shift control device.

<Structure> As shown in FIG. 1, the hybrid electric vehicle is of a series type including a traveling motor 1 as two AC induction motors and an engine 2 for power generation. A transmission 3 is interposed between the traveling motor 1 and the driving wheels 4, and the driving force of the traveling motor 1 is transmitted to the driving wheels 4 via the transmission 3 and the like. The transmission 3 has, for example, two speed stages of a high speed (H) and a low speed (L). Switching of the speed from L to H or from H to L is performed by the shift fork driving hydraulic actuator 10. It has become.

On the other hand, a generator 5 is connected to the engine 2, and the generator 5 generates power by driving the engine 2. The electric power generated by the generator 5 is supplied to the traveling motor 1 and simultaneously stored in the battery 6. That is, the driving power of the traveling motor 1 is supplied from the battery 6 or the generator 5 via the inverter 7.

When switching the gear position of the transmission 3 from L to H or from H to L, the ECU 8 as a control device
Thus, the following shift control is performed.

As shown in FIG. 1, the ECU 8 receives an actual vehicle speed V, an actual motor speed N, a switching command signal S, an accelerator pedal depression amount A, and the like. The actual vehicle speed V is detected by a vehicle speed detector 15 which is a vehicle speed detecting means provided on the output side of the transmission 3, and the actual motor rotation speed N is detected by a rotation speed detector 14 provided on the input side of the transmission 3. Is done. Further, the switching command signal S is changed from L output to H or H output from the shift operation switch 11 which is a shift command means.
From L to L. The accelerator pedal depression amount A is the depression amount of the accelerator pedal 12,
Accelerator opening detector 1 provided on accelerator pedal 12
3 is detected.

As shown in FIG. 2, in the ECU 8, when the driver operates the shift operation switch 11, and when the shift operation switch 11 outputs a command signal S for switching from L to H or from H to L, this signal is output. S10 to S4 based on
0 processing is performed.

First, at S10, a gear release control is performed. That is, regardless of the depression amount A of the accelerator pedal 12, the torque of the traveling motor 1 is set to zero, and then the shift fork drive hydraulic pressure of the currently connected shift stage in the shift fork drive hydraulic actuator 10 is turned off. As a result, the gear at the gear is removed to put the transmission 3 in the neutral state.

Thereafter, in S20, synchronization control is performed. Here, the target motor speed is corrected in consideration of a change in vehicle speed from when the synchronization condition is satisfied and the shift fork drive hydraulic pressure ON command is output until the gear at the target shift speed is actually connected. The synchronous control is performed based on the corrected target motor rotation speed, the details of which will be described later.

When the actual motor speed N is synchronized with the corrected target motor speed, a gear connection control is performed in S30.
That is, the shift speed of the transmission 3 is switched to the target shift speed by connecting the shift fork drive hydraulic pressure of the target shift speed in the shift fork drive hydraulic actuator 10 to ON (the gear of the target shift speed is connected). Thus L
From H to H or from H to L is completed. It should be noted that there is a delay of about 0.2 seconds from when the synchronization condition is satisfied and the shift fork drive hydraulic pressure ON command is output to when the gear at the target shift speed is actually connected.

After the shift is completed, a torque rise control is performed in S40. That is, by outputting a control signal corresponding to the depression amount A of the accelerator pedal 12 to the inverter 7 to control the output of the traveling motor 1, the accelerator torque is gradually increased.

The above is the overall flow of the shift control.
Here, the synchronization control in S20 will be described in detail with reference to FIG.

As shown in FIG. 1, first, in S21, the amount of change in the actual vehicle speed in the neutral state (coasting state) is calculated to calculate the amount of change in the target motor speed (change amount calculating means). That is, the change amount (km / h) of the actual vehicle speed based on the actual vehicle speed V (km / h) detected by the vehicle speed detector 15.
/ S), and further calculates the change amount of the target motor speed from the change amount (km / h / s) of the actual vehicle speed in consideration of the gear ratio of the target shift speed as shown in equation (1). The unit of the change amount of the target motor speed obtained from the equation (1) is (km
/ H / s), this is further converted to a unit to determine the change amount (rpm / s) of the target motor speed. At this time, if the vehicle is traveling on a steep ascending or descending slope, the speed of the coasting vehicle is greatly reduced or accelerated, so that the amount of change in the actual vehicle speed becomes large and the amount of change in the target motor speed is increased. Also increases.

The amount of change in target motor speed = the amount of change in actual vehicle speed × gear ratio of target gear

Subsequently, in S22, a correction value of the target motor speed is calculated (correction value calculation means). That is, the change in the actual vehicle speed from the time when the synchronization condition is satisfied and the ON command of the shift fork driving hydraulic pressure is output to the time when the gear at the target shift speed is actually connected (0.2 seconds) is considered. To
As shown in equation (2), a correction value (rpm) is calculated from the amount of change in the target motor speed and the speed change time 0.2 seconds.

Correction value = change amount of target motor speed × 0.2 (2)

After the calculation of the correction value, in S23, the target motor speed after shifting is calculated (target motor speed calculating means).
That is, the target motor rotation speed is calculated from the actual vehicle speed V (km / h) detected by the vehicle speed detector 15 as in equation (3), taking into account the gear ratio of the target shift speed. Since the unit of the target motor speed obtained from the equation (3) is (km / h), the target motor speed (r) is further converted into a unit.
pm).

Target motor rotation speed = actual vehicle speed × gear ratio of target shift speed (3)

In S24, the target motor speed calculated in S23 is corrected (target motor speed correcting means). That is, as shown in equation (4), the correction target motor speed (rpm) is obtained by adding the correction value (rpm) to the target motor speed (rpm) calculated in S23. as a result,
The corrected target motor rotation speed decreases by the correction value when the actual vehicle speed decreases, and increases by the correction value when the actual vehicle speed increases.

Corrected target motor speed = target motor speed + correction value (4)

Subsequently, in S25, the actual motor speed control is performed (motor control means). That is, the output (torque) of the traveling motor 1 is controlled by controlling the drive power supplied from the inverter 7 to the traveling motor 1 with the corrected target motor rotation speed as a target value, and the actual target motor rotation speed N is calculated. Synchronize with the correction target motor speed (S25). During this synchronization control, it is determined in S26 whether or not the synchronization condition is satisfied (whether or not the actual motor rotation speed is equal to the corrected target motor rotation speed). If the synchronization condition is not satisfied, the process returns to S23. . In S23, a new target motor speed is calculated again based on the actual vehicle speed V at this time. In S24, the new target motor speed is corrected. In S25, the new corrected target motor speed is calculated. Synchronous control is performed as a target value.

That is, the actual vehicle speed changes when the vehicle is traveling on a steep uphill or downhill road even after the target motor speed is calculated in S24 and before the synchronization condition is satisfied. By monitoring the change in the vehicle speed and reflecting the change in the target motor speed, the actual motor speed N is synchronized with the target motor speed according to the actual vehicle speed V at this time when the synchronization condition is satisfied.

During the neutral state (for example, 1.
Since it is considered that the change amount of the actual vehicle speed does not substantially change in (5 seconds), in the flowchart of FIG. 3, only the change amount of the actual vehicle speed is obtained from the actual vehicle speed V immediately after the vehicle enters the neutral state. However, if it is necessary to consider the change in the actual vehicle speed change during the neutral operation, the process proceeds to S26.
Then, when the synchronization condition is not satisfied, the process may return to the calculation of the change amount of the actual vehicle speed (change amount of the target motor speed) in S21.

After the synchronization condition is satisfied, S3 is executed as shown in FIG.
0 gear connection control (shift control means). At this time,
Since the actual motor speed N is synchronized with the corrected target motor speed corresponding to the actual vehicle speed V at the moment when the gear at the target gear is engaged, the gear is connected smoothly.

<Operation / Effect> As described above, according to the shift control device of the present embodiment, the target in the neutral state is determined based on the output (actual vehicle speed V) of the vehicle speed detector 15 and the gear ratio of the target shift speed. The amount of change in the motor speed is calculated, and a correction value is calculated based on the speed change time of the shift speed (here, 0.2 seconds) and the amount of change in the target motor speed. The target motor speed after the shift is calculated based on the gear ratio of the target shift speed. Then, the target motor rotation speed is corrected by the correction value, and the actual motor rotation speed N is synchronized with the target motor rotation speed by controlling the motor output using the corrected corrected target motor rotation speed as a target value. When the actual motor speed and the corrected target motor speed are synchronized, the speed of the transmission is switched to the target speed.

For this reason, even if the actual vehicle speed changes at the time of gear change of the gear because the vehicle is traveling on a steep ascending or descending slope, the actual motor speed N is increased at the moment when the gear of the target gear is engaged. Of the vehicle, the gear can be connected smoothly without generating gear noise, and the gear can be shifted reliably.

In the above, the case of the hybrid electric vehicle (HEV) has been described, but the present invention is not limited to this, and the present invention can be applied to a pure electric vehicle (EV).

[0037]

As described above in detail with the embodiment of the present invention, according to the shift control device for an electric vehicle of the present invention, the output of the vehicle speed detector means and the gear ratio of the target shift speed are determined. The amount of change in the target motor speed in the neutral state is calculated, and a correction value is calculated based on the speed change time of the shift speed and the amount of change in the target motor speed. A target motor rotation speed after gear shifting is calculated based on the ratio. Then, the target motor speed is corrected by the correction value, and the actual motor speed is synchronized with the target motor speed by controlling the motor output with the corrected target motor speed as a target value, When the actual motor speed and the corrected target motor speed are synchronized, the speed of the transmission is switched to the target speed.

For this reason, even if the actual vehicle speed changes at the time of gear change of the gear due to traveling on a steep ascending or descending slope, the actual motor speed is increased at the moment when the gear of the target gear is engaged. Since the number of revolutions can be set to correspond to the actual vehicle speed, the gears can be connected smoothly without generating gear noise, and the gear can be shifted reliably.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hybrid electric vehicle including a shift control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an overall process of the shift control device.

FIG. 3 is a flowchart showing the content of synchronous control of the transmission control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Running motor 2 Engine 3 Transmission 4 Driving wheel 5 Generator 6 Battery 7 Inverter 8 ECU 10 Hydraulic actuator for shift fork drive 11 Shift operation switch 12 Accelerator pedal 13 Accelerator opening detector 14 Revolution detector 15 Vehicle speed detector A Accelerator pedal depression amount N Actual motor speed S Switching command signal S V Actual vehicle speed

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J052 AA01 CA11 EA04 FB33 GC43 GC44 GC46 GC72 LA08 5H115 PG04 PI22 PU09 PU24 PU25 PU26 PV09 QE04 QE06 QN06 QN15 RB08 RB11 SE08 TB01 TO21

Claims (1)

[Claims] 1. A shift control device for an electric vehicle that switches a shift stage of a transmission interposed between a traveling motor and a drive wheel to a target shift stage via a neutral state based on an output of a shift command unit. A vehicle speed detecting means for detecting a vehicle speed of the vehicle; a change amount calculating means for calculating a change amount of a target motor speed in the neutral state based on an output of the vehicle speed detecting means and a gear ratio of the target shift speed; Correction value calculating means for calculating a correction value based on the speed change time of the shift speed and the output of the change amount calculating means; and a target after shifting based on the output of the vehicle speed detecting means and the gear ratio of the target gear. Target motor speed calculating means for calculating the motor speed, target motor speed correcting means for correcting the target motor speed with the correction value, and the corrected corrected target motor Motor control means for controlling the motor output using the rotation speed as a target value, and shift control means for switching the gear position of the transmission to the target gear position when the actual motor rotation speed and the corrected target motor rotation speed are synchronized. And a shift control device for an electric vehicle.