JP2000102114A - Creep force generating equipment of electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain creep force generating equipment of an electric vehicle which can generate a constant creep force independently of a plurality of traveling stages. SOLUTION: This creep force generating equipment is provided with a controller 11 changing the output of a motor 1 for traveling, for a plurality of traveling stages, so as to make the creep force constant. Independently of traveling stages such as an H gear and an L gear, a constant creep force is generated. In the case of creep traveling of any traveling stage, a nearly constant creep force is outputted. In any traveling stage, creep traveling free from sense of incongruity can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a creep generator for an electric vehicle which generates a creep force required for creep running.

[0002]

2. Description of the Related Art AT vehicles using an internal combustion engine as a driving power source (vehicles in which a torque converter and an automatic transmission are combined).
The characteristic is that when the shift position is at the driving position "D (drive) position" due to stall torque generated from the torque converter, the vehicle travels at an extremely low speed even if the accelerator pedal is not depressed. The running by the stall torque is called creep running.

[0003] In this creep running, the speed of the vehicle can be easily adjusted only by operating the brake. Therefore, the creep running can be used to operate the vehicle at an extremely low speed, for example, to handle a vehicle such as a garage or parallel parking. Is being done.

[0004] On the other hand, in general, an electric vehicle using a motor as a driving source for traveling is designed to suppress unnecessary power consumption.
When in the running position, unless you depress the accelerator pedal,
A control that does not generate torque is adopted for the motor, so that creep running like an AT car using an internal combustion engine cannot be performed.

[0005] For this reason, when switching from an accustomed AT vehicle with an internal combustion engine to an electric vehicle, creeping cannot be performed, so that the driver can feel uncomfortable when handling the vehicle such as putting it in a garage.

Therefore, in the electric vehicle, Japanese Patent No. 2741 is disclosed.
As disclosed in Japanese Patent No. 739, only when the vehicle speed is in a very low vehicle speed range (the vehicle speed is equal to or lower than a predetermined speed), that is, when the vehicle speed is lower than the creep limit speed, the motor is operated at a low output to generate a creep force; It is being done to enable creep running.

[0007] Incidentally, similarly to a vehicle equipped with an internal combustion engine, an electric vehicle is equipped with a transmission having a plurality of gears, specifically, two gears such as L (low) and H (high). In this way, it is possible to run with maximum use of the motor capacity. Specifically, a two-stage shift (L gear / H
In the case of normal driving, the vehicle travels in the H gear (gear having a high gear ratio), and during traveling, switches to the L gear (gear having a low gear ratio) for rapid acceleration, or runs on a steep slope. For example, the L stage is selected from the beginning to start the vehicle, and the traveling stage is properly used.

[0008]

By the way, in an electric vehicle, when a creep force is generated, a constant motor torque (creep torque) is generated from a traveling motor. That is, in the electric vehicle having the traveling stage of the L gear / H gear, the creep traveling is performed in both the L gear and the H gear.

However, in the creep running, since the motor torque generated by the running motor is constant, the creep output from the driving wheels for each difference in the gear ratio of the H gear / L gear and for each shift position (L gear or H gear). Force (driving force) is different. Specifically, since the gear ratio of the H gear is high, the creep running performed by the H gear is performed with a smaller creep force than the creep running performed by the L gear.

[0010] For this reason, during creep running, the creeping force is different for each traveling stage, which may cause the driver to feel uncomfortable. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a creep generator for an electric vehicle that can generate a constant creep force regardless of a plurality of traveling stages.

[0011]

According to a first aspect of the present invention, there is provided a creep force generating apparatus for an electric vehicle, wherein the creep force is constant at each traveling stage detected by the operating position detecting means. Thus, a control means for changing the output of the traveling motor is provided so that a constant creep force is generated regardless of the traveling stage. As a result, even when the traveling stage is changed, the same creep force acts during any creep traveling, so that creep traveling can be performed without feeling uncomfortable due to the traveling stage.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on one embodiment shown in FIGS. FIG. 1 shows a schematic configuration of an electric vehicle. In the drawing, reference numeral 1 denotes a traveling motor disposed between, for example, rear wheels 2 and 2 (drive wheels); For example, a transmission (transmission) having two traveling stages such as an L gear / H gear determined by two types of gear ratios. Reference numeral 3a denotes an actuator that switches between the L gear and the H gear.

The output of the transmission 3 is connected to the rear wheels 2 and 2 via a differential gear 4, for example.
2 so that the rear wheels 2 and 2 can be driven using the traveling motor 1 as a power source.

A battery 5 is mounted in the center of a vehicle body (not shown). The terminal of the battery 5 is connected to a wiring 6 extending from a connection terminal of the traveling motor 1 so that the electric power of the battery 4 can be supplied to the traveling motor 1.

A power generation unit 8 is mounted between the front wheels 7,7. The power generation unit 8 includes an engine 9 and a generator 10 connected to an output section of the engine 9 so that the generator 10 can be driven by using the engine 9 as a drive source.

The output terminal of the generator 10 is connected to the extending end of the wiring 6 so that the power generated by the generator 10 can be supplied to the battery 5 and the traveling motor 1 through the wiring 6. .

On the other hand, 11 is a controller (corresponding to control means). The controller 11 is composed of, for example, a microcomputer. The controller 11 includes a traveling motor 1, an actuator 3 a, a charge capacity sensor 5 a mounted on the battery 5, an engine 9, a vehicle speed sensor 12 (vehicle speed detecting means) mounted on the differential gear 4, and a shift operation of the transmission 3. Is connected to a shift position sensor 14 (corresponding to an operation position detecting means) for detecting an operation position of a shift device 13 (corresponding to a shift operating means) for performing the operation.

The controller 10 has a function of running with only the power of the battery 5, a function of starting the engine 9 and operating the generator 10 when the power of the battery 5 falls below a predetermined value, and a function of charging the battery 5 by power generation. A function of driving the traveling motor 1 while stopping the operation of the engine 9 when the battery 5 is charged to a predetermined amount of power is set. According to the state of the battery 5, only the power of the battery 5 is set. , And the power generation traveling by the electric power of the generator 10 is performed. The controller 10 is provided with a function of driving the actuator 3a so as to switch to a predetermined traveling stage in accordance with a shift operation of the shift device 12, and performs a shift operation to the H gear or the L gear.
When the accelerator pedal is depressed, traveling by electric power of only the battery 5 and electric power generation by electric power of the generator 10 are performed.

A combination of the controller 11, the traveling motor 1, the shift position sensor 14, and the vehicle speed sensor 12 constitutes a creep force generator 16. By using the creep force generating device 16, when the vehicle speed is extremely low below the creep limit vehicle speed, the traveling motor 1 is operated at a low output to generate creep force, so that creep traveling is executed.

The creep force generating device 16
The present invention is devised so that a constant creep force is output irrespective of the traveling stage (H gear / L gear).

This involves controlling the output of the traveling motor 1 for each traveling stage so that substantially the same creep force is generated when the creep force is generated, taking into account the difference in the gear ratios of the traveling stages. Used.

For example, when the creep force is generated by the L gear, the traveling motor 1 is driven so that the motor torque value (creep torque) set for generating the conventional creep force is output. When the creep force is generated in step (1), control is performed to drive the traveling motor 1 so as to output the difference between the gear ratio of the H gear and the L gear and the motor torque value having the increased motor torque. More specifically, as shown in FIG. 2A, a map (vehicle speed-motor torque) of the L-gear motor torque A for generating the creep force is shown as shown in FIG. The difference between the gear ratio of the transmission 3 for the L-motor torque A and the map of the H-gear motor torque B (vehicle speed-motor torque) are set in the controller 11.
During the creep running of the gear, the running motor 1 is operated so as to generate the motor torque A for the L gear, and during the creep running of the H gear, the running motor 1 is operated so as to generate the motor torque B for the H gear. Control is used.

With this control, substantially the same creep force (drive force) is output from the rear wheels 2, 2 (drive wheels) in the H gear and the L gear during creep running, regardless of the running speed. is there.

An example of this control is shown in the flowchart of FIG. Explaining the generation of the creep force based on this flowchart, now, the vehicle speed of the electric vehicle is lower than the creep limit speed, and the depression amount of the brake pedal becomes equal to or less than a predetermined value. Suppose control has been transferred.

Then, the controller 11 proceeds from step S1 for determining whether or not the mode is the creep mode to step S2, and determines at which operation position the shift device 13 is located. At this time, if the shift device 13 has been shifted to the L gear, the process proceeds to step S3, and the value of the L gear motor torque A corresponding to the vehicle speed is read from the map shown in FIG. If the shift device 13 has been shifted to the H gear, the process proceeds to step S4, and the value of the H gear motor torque B corresponding to the vehicle speed is read from the map shown in FIG.

Here, the H gear motor torque value is a value obtained by increasing the gear ratio difference between the H gear and the L gear of the transmission 3 and the L gear motor torque value. Therefore, the process proceeds to step S5, and even if the traveling motor 1 is operated by the instruction of the controller 11 so as to have the torque value (creep torque) of the read L gear motor torque A, the read H gear Even if it operates so that the torque value (creep torque) of the motor torque B for
As shown in the map of (c), the same creep force C is output from both the rear wheels 2 and 2. That is, a constant creep force is generated regardless of the traveling stage.

Therefore, in the creep mode, a substantially constant creep force is applied regardless of the change of the traveling gear such as the H gear or the L gear, and the creep traveling without any discomfort can be realized at any traveling gear. .

In the above-described embodiment, the motor torque at the time of the H gear is increased by the difference between the gear ratios of the H gear / L gear in order to output a constant creep force. The motor torque at the time of L gear is H gear / L
The difference between the gear ratios of the gears may be reduced to output a constant creep force.

Further, in the above-described embodiment, an example using a two-speed transmission is described. However, the present invention is not limited to this, and a transmission in which a higher traveling speed is set may be used.

[0030]

As described above, according to the first aspect of the present invention, the output of the traveling motor is changed during creep traveling so that the creep force is constant at each traveling stage. Irrespective of the traveling stage, a constant creep force can be generated, and creep traveling without discomfort can be realized at any traveling stage.

[Brief description of the drawings]

FIG. 1 is a view for explaining a creep force generating device for an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining generation control of a creep force in the creep force generation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Moving motor 5 ... Battery 8 ... Generating unit 11 ... Controller (control means) 13 ... Shift device (shift operation means) 14 ... Shift position sensor (operation position detecting means).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobuaki Takeda 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation F-term (reference) 5H115 PA01 PC06 PG04 PI16 PI22 PI29 PO06 PU01 PU24 PU26 QN03 RB08 RB17 RB21 RE01 SE03 SE08 TB01 TI01 TO23 TO30

Claims (1)

[Claims] 1. A creep force generator for an electric vehicle that generates a creep force by operating a traveling motor at a low output when a vehicle speed is equal to or lower than a predetermined speed. Speed change operation means; operation position detection means for detecting an operation position of the speed change operation means; and an output of the traveling motor such that the creep force is constant for each traveling stage detected by the operation position detection means. And a control means for changing the creep force of the electric vehicle.