Vehicle control device

• US 6,366,838 B1
• Filed: 01/19/2001
• Issued: 04/02/2002
• Est. Priority Date: 01/20/2000
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Yoshino, Takahiro, Nakajima, Yuki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US09/764,069
• Time in Patent Office: 438 Days
• Field of Search: 701/22, 318/139, 307/9.1, 307/10.7, 320/104, 324/378
• US Class Current: 701/22
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor

Abstract

The output of an engine is recovered by a generator. A motor is driven by the electric power generated by the generator. When there is a sudden acceleration, etc., the generation power output by the generator is delayed, and when the electric power supplied to the motor is insufficient, the insufficient part is supplied from a battery. The maximum power output of the battery decreases according to battery temperature. However, as the response of the generation power output of the generator is increased if battery temperature is low, the above-mentioned insufficient part is always suppressed below the maximum power output of the battery. In this way, the inability of the battery to supply electric power required for acceleration is prevented, and thus the problem of poor acceleration is eliminated.

Claims

1. A control device for a vehicle, wherein the vehicle comprises:

an engine;

a generator which rotates in synchronism with the engine, and regenerates the output of the engine;

a motor driven by the electric power regenerated by the generator, and

an electric energy storage device which supplies electric power to the motor, wherein when the electric power supplied to the motor from the generator is insufficient due to response delay of the generation power output from the generator, the electric power to cover the insufficient amount is supplied to the motor from the electric energy storage device, and the control device comprises;

a sensor which detects the temperature of the electric energy storage device, and

a microprocessor programmed to enhance the response of the generation power output of the generator according to the decline of the temperature of the electric energy storage device.

2. A control device as defined in claim 1, wherein the microprocessor is further programmed to enhance the response of the generation power output of the generator by increasing the torque margin of the engine.

3. A control device as defined in claim 2, wherein the microprocessor is further programmed to increase the torque margin of the engine the lower the temperature of the electric energy storage device.

4. A control device as defined in claim 2, wherein the microprocessor is further programmed to increase the torque margin of the engine by adjusting the target rotation speed of the generator and the engine.

5. A control device as defined in claim 2, wherein the microprocessor comprises a map for computing the target rotation speed of the generator and engine set so that the engine has a predetermined torque margin, and the microprocessor is further programmed to give a predetermined torque margin to the engine by computing the target rotation speed of the generator and engine by looking up in the map.

6. A control device for a vehicle, wherein the vehicle comprises:

an engine;

a generator mechanically connected to the engine;

a motor electrically connected to the generator, and mechanically connected to the drive shaft of the vehicle, and

an electric energy storage device electrically connected to the generator and motor, and the control device comprises;

a first sensor which detects the running conditions of the vehicle;

a second sensor which detects the temperature of the electric energy storage device, and

a microprocessor programmed to;

compute a target motor output based on the running conditions of the vehicle, the target motor output expressing the output of the motor for driving the vehicle according to the running conditions,

compute a target engine output based on the target motor output, the target engine output expressing the output of the engine for causing the generator to generate electric power according to the target motor output,

compute a first target rotation speed of the generator based on the target engine output, the first target rotation speed expressing the rotation speed of the generator for making the output of the engine coincide with the target engine output at an optimum fuel cost-performance,

compute a second target rotation speed of the generator based on the target engine output and the temperature of the electric energy storage device, the second target rotation speed expressing the rotation speed of the generator which makes the output of the engine coincide with the target engine output, and makes the torque margin of the engine a value according to the temperature of the electric energy storage device,

select one of the first target rotation speed and second target rotation speed as a third target rotation speed, and

control the rotation speed of the generator based on the third target rotation speed.

7. A control device as defined in claim 6, wherein the microprocessor is further programmed to select the larger of the first target rotation speed and second target rotation speed as the third target rotation speed.

8. A control device for a vehicle, wherein the vehicle comprises:

an engine;

a generator which rotates in synchronism with the engine, and regenerates the output of the engine;

a motor driven by the electric power regenerated by the generator, and

an electric energy storage device which supplies electric power to the motor, wherein when the electric power supplied to the motor from the generator is insufficient due to response delay of the generation power output from the generator, the electric power to cover the insufficient amount is supplied to the motor from the electric energy storage device, and the control device comprises;

means for detecting the temperature of the electric energy storage device, and

means for enhancing the response of the generation power output of the generator according to the decline of the temperature of the electric energy storage device.

9. A control device for a vehicle, wherein the vehicle comprises:

an engine,

a generator mechanically connected to the engine;

a motor electric connected to the generator, and mechanically connected to the drive shaft of the vehicle, and

an electric energy storage device electrically connected to the generator and motor, and the control device comprises;

means for detecting the running conditions of the vehicle;

means for detecting the temperature of the electric energy storage device;

means for computing a target motor output based on the running conditions of the vehicle, the target motor output expressing the output of the motor for driving the vehicle according to the running conditions;

means for computing a target engine output based on the target motor output, the target engine output expressing the output of the engine for causing the generator to generate electric power according to the target motor output;

means for computing a first target rotation speed of the generator based on the target engine output, the first target rotation speed expressing the rotation speed of the generator for making the output of the engine coincide with the target engine output at an optimum fuel cost-performance;

means for computing a second target rotation speed of the generator based on the target engine output and the temperature of the electric energy storage device, the second target rotation speed expressing the rotation speed of the generator which makes the output of the engine coincide with the target engine output, and makes the torque margin of the engine a value according to the temperature of the electric energy storage device;

means for selecting one of the first target rotation speed and second target rotation speed as a third target rotation speed, and

means for controlling the rotation speed of the generator based on the third target rotation speed.