Control device for hybrid vehicle

• US 9,421,967 B2
• Filed: 03/06/2013
• Issued: 08/23/2016
• Est. Priority Date: 03/13/2012
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Ueno, Munetoshi
• Primary Examiner(s): Badii, Behrang
• Assistant Examiner(s): GREENE, DANIEL LAWSON
• Application Number:
  US14/375,803
• Publication Number:
  US 20150019061A1
• Time in Patent Office: 1,266 Days
• US Class Current: 1/1
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• 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 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor

Abstract

A control device for a hybrid vehicle is configured to enter a driving mode in which a preset engine-start condition is met, and is configured to enter electric vehicle mode when a preset engine-stop condition is met, and includes an engine-start-condition-controlling device which, during travel in the electric vehicle mode, in the event that an electric vehicle travel zone expansion condition that has been set on the basis of vehicle speed VSP and torque demand information reflective of demand by the driver, and that expands the travel zone in the electric vehicle mode, is met, changes the engine-start condition from a baseline start condition, to an expansion engine-start condition for expanding the travel zone in the electric vehicle mode, doing so for the duration of a prescribed time thereafter.

Claims

1. A control device for a hybrid vehicle, the hybrid vehicle including an engine, a motor for a drive system extending from the engine to a drive wheel and for starting the engine and driving the drive wheel, and a mode switching device configured to bring about a hybrid vehicle mode in which rotation of the motor is transmitted to the engine when a preset engine-start condition is met and the engine is started so that the engine and the motor serve as drive sources, and being configured to stop the engine and bring about an electric vehicle mode in which the motor serves as the drive source when a preset engine-stop condition is met, the mode switching device being provided to a part linking the engine and the motor, the control device comprising:

an engine-start-condition-controlling device programmed to cause the engine-start condition to be changed when the vehicle is traveling in electric vehicle mode and an electric vehicle travel zone expansion condition is met for a prescribed time after the electric vehicle travel zone expansion condition has been met, from a baseline start condition that prevails when the electric vehicle travel zone expansion condition is not met to an expansion engine-start condition for expanding the travel zone in the electric vehicle mode, the electric vehicle travel zone expansion condition being set on the basis of vehicle speed and torque demand information reflective of demand by a driver, and the travel zone in the electric vehicle mode being expanded under the electric vehicle travel zone expansion condition,

the engine-start-condition-controlling device being further programmed to set a time at which to set the engine-start condition to the expansion engine-start condition, the time being set based on at least one of the torque demand information and a state of battery charge.

2. The control device for a hybrid vehicle according to claim 1, wherein

the engine-start-condition-controlling device is programmed to cancel the expansion engine-start condition when the expansion engine-start condition is met, or when the torque demand information is equal to or less than a preset torque threshold value.

3. The control device for a hybrid vehicle according to claim 1, wherein

the engine-start-condition-controlling device being programmed to cause the engine-start condition to be changed when the vehicle is traveling in the electric vehicle mode and the electric vehicle travel zone expansion condition is met, and prior to the elapsing of a period of time over which the engine-start condition is set to the expansion engine-start condition, the torque demand information is equal to or greater than a preset torque demand threshold value, and motor output torque is equal to or greater than an upper limit value of motor travel torque that can be employed for travel in an electric travel mode when the engine-start condition has been set to the baseline engine-start condition, the engine-start-condition-controlling device being configured to change the engine-start condition from the expansion engine-start condition to the baseline engine-start condition.

4. The control device for a hybrid vehicle according to claim 1, wherein

the engine-start-condition-controlling device being programmed to cause the engine-start condition to be changed when the vehicle is traveling in the electric vehicle mode and the electric vehicle travel zone expansion condition is met, and under the expansion engine-start condition, the torque demand information has exceeded an expansion start line set to a larger value than a base start line preset according to vehicle speed, and

the engine-start-condition-controlling device is configured to set the amount of expansion of the expansion start line with respect to the base start line, on the basis of the vehicle speed and/or the state of battery charge.

5. The control device for a hybrid vehicle according to claim 1, wherein

the engine-start-condition-controlling device being programmed to cause the engine-start condition to be changed when the vehicle is traveling in the electric vehicle mode and the electric vehicle travel zone expansion condition is met, and under the expansion engine-start condition, torque demand information reflective of demand by the driver has exceeded an engine-start line which has been set according to vehicle speed,

under the engine-stop condition, the torque demand information is below an engine stop line which has been set according to vehicle speed,

the engine-start-condition-controlling device, when setting the engine-start condition to the expansion engine-start condition, is programmed to set the engine-stop line to a base stop line obtained by subtracting preset hysteresis from a base start line preset according to vehicle speed, and

when setting the engine-start line to a contraction start line of a smaller value than the base start line, is configured to set the engine-stop line to a contraction stop line derived by subtracting preset hysteresis from the contraction start line.

6. The control device for a hybrid vehicle according to claim 1, wherein

the engine-start-condition-controlling device being programmed to cause the engine-start condition to be changed when the vehicle is traveling in the electric vehicle mode and the electric vehicle travel zone expansion condition is met, under the electric vehicle travel zone expansion condition, the amount of change, per unit of time, in the torque demand information exceeds a preset threshold value of change in torque demand.

7. The control device for a hybrid vehicle according to claim 6, further comprising

an intent-to-accelerate-determining device programmed to detect an intent-to-accelerate index used to determine an intention on the part of the driver to accelerate,

the intent-to-accelerate index being equal to or less than a preset intent-to-accelerate threshold value under the electric vehicle travel zone expansion condition.

8. The control device for a hybrid vehicle according to claim 6, wherein

the engine-start-condition-controlling device is programmed to cancel the expansion engine-start condition when the expansion engine-start condition is met, or when the torque demand information is equal to or less than a preset torque threshold value.

9. The control device for a hybrid vehicle according to claim 1, further comprising

an intent-to-accelerate-determining device programmed to detect an intent-to-accelerate index used to determine an intention on the part of the driver to accelerate,

the intent-to-accelerate index being equal to or less than a preset intent-to-accelerate threshold value under the electric vehicle travel zone expansion condition.

10. The control device for a hybrid vehicle according to claim 9, wherein

the engine-start-condition-controlling device is programmed to cancel the expansion engine-start condition when the expansion engine-start condition is met, or when the torque demand information is equal to or less than a preset torque threshold value.

11. The control device for a hybrid vehicle according to claim 1, wherein

the engine-start-condition-controlling device is programmed to cause the engine-start condition to be changed when the vehicle is traveling in the electric vehicle mode and the electric vehicle travel zone expansion condition is met, and under the engine-starting condition, torque demand information reflective of demand by the driver has exceeded an engine start line set according to vehicle speed,

the engine-start-condition-controlling device is programmed to calculate an expansion start line set to a larger value than a base start line preset according to vehicle speed, and

an intent-to-accelerate for which there is assigned a greater value with respect to the base start line when a weighted mean value of the accelerator position or a weighted mean value of the accelerator opening rate is equal to or greater than a preset threshold value, and for which there is assigned a smaller value with respect to the base start line when the weighted mean value of the accelerator position or the weighted mean value of the accelerator opening rate is less than the preset threshold value and

the smaller of the expansion start line and the intent-to-accelerate start line is implemented as a final engine-start line.

12. The control device for a hybrid vehicle according to claim 11, wherein

the engine-start-condition-controlling device being programmed to cause the engine-start condition to be changed when the vehicle is traveling in the electric vehicle mode and the electric vehicle travel zone expansion condition is met, and the intent-to-accelerate line is set to a value such that, with respect to the absolute value of the difference between the threshold and either the weighted mean value of the accelerator position or the weighted mean value of the accelerator opening rate, the amount of expansion when set to a larger value with respect to the base start line is greater than the amount of contraction when set to a smaller value with respect to the base start line.