Control device and control method for hybrid vehicle

• US 20030074115A1
• Filed: 10/02/2002
• Published: 04/17/2003
• Est. Priority Date: 10/11/2001
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Komiyama, Susumu, Yamaguchi, Musashi
• Granted Patent: US 6,629,027 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/429 Current
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/15 Preventing overcharging
• 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 10/10 including control of change-speed gearings
• 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 20/13 : in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/0604 : Throttle position
• CPC Class Codes: B60W 2510/0638 : Engine speed
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2510/246 : Temperature
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2710/0666 : Engine torque
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 50/0097 : Predicting future conditions
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration
• CPC Class Codes: Y10S 903/918 : Continuously variable
• CPC Class Codes: Y10S 903/919 : Stepped shift
• CPC Class Codes: Y10S 903/945 : Characterized by control of gearing, e.g. control of transmission ratio
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

A control device and control method for a hybrid vehicle is disclosed having an electric storage detecting section 13 which detects a state of charge (SOC) of an electric storage device 10. A target running efficiency calculating section 14 serves as a unit to calculate a target value of a running efficiency, indicative of a proportion of a given physical quantity, in terms of a drive power rate required for driving the vehicle such that the higher the SOC detected value, the smaller will be the target value. A target unit operating point calculating section 15 calculates a target value of a unit operating point, providing the target running efficiency, from among operating points, that cause a power rate of an internal combustion engine 1 to be utilized at the running efficiency with the maximum efficiency, of a unit 11 (the internal combustion engine 1, a clutch 2, a motor 3 and a stepped power transmission 4), and a target unit operating point actualizing section 16 operates the unit 11 at the target unit operating point.

Claims

1. A control device for a hybrid vehicle, including a unit having an internal combustion engine, a motor, a stepped power transmission and an electric storage device adapted to supply electric power output to the motor, wherein at least one of power outputs of the internal combustion engine and the motor is transmitted through the stepped power transmission to an output shaft thereof, the control device comprising:

a state of charge detecting section detecting an SOC value indicative of a remaining charged capacity of an electric storage device;

a target running efficiency calculating section calculating a target value of a running efficiency, indicative of a proportion of a given physical quantity, in terms of a drive power rate required for driving the vehicle, in such a manner that the higher the SOC value, the small will be the target value to be calculated;

a target unit operating point calculating section calculating a target value of a unit operating point, that forms the target running efficiency, from among operating points of a unit which cause the drive power rate provided by an internal combustion engine to be utilized at the running efficiency with the maximum efficiency; and

a target unit operating point actualizing section controlling the unit such that the unit is operated at the target unit operating point.

2. The control device for the hybrid vehicle according to claim 1, wherein the running efficiency is a proportion of the amount of fuel, in terms of the drive power rate required for driving the vehicle, to be consumed for producing the drive power rate.

3. The control device for the hybrid vehicle according to claim 1, wherein the running efficiency is a proportion of a mass of ingredients, in terms of the drive power rate required for driving the vehicle, which are exhausted from the engine in order to provide the drive power rate while the ingredients are limited from being exhausted.

4. The control device for the hybrid vehicle according to claim 1, further comprising:

a chargeable and dischargeable power output calculating section calculating a chargeable and dischargeable power output of the electric storage device and operative to serve as a unit to allow the unit operating point, that permit the electric storage device to be charged and discharged within a chargeable and dischargeable power output range, to be assigned to the target value of the unit operating point.

5. The control device for the hybrid vehicle according to claim 1, wherein the target unit operating point calculating section serves as a unit to calculate the target value of the unit operating point so as to interrupt a gear shift for a given time interval in the absence of variation in a demanded drive power,

6. The control device for the hybrid vehicle according to claim 5, wherein the target unit operating point calculating section comprises:

a demanded drive power variation detecting section detecting variation in the demanded drive power output;

an SOC transition predicting section predicting an SOC transition in a case where in the absence of variation in the demanded drive power, it is assumed that the unit is operated for a given time interval using the preliminarily calculated target unit operating point; and

a target unit operating point predicting section predicting the target unit operating point based on the target running efficiency calculated on the basis of the predicted SOC transition;

wherein when an occurrence of the gear shift within the given time interval after prediction of the target unit operating point is predicted, the target unit operating point calculating section serves as a unit to cause the target unit operating point used in a previous calculation to be assigned to the target value of the unit operating point.

7. The control device for the hybrid vehicle according to claim 1, wherein the target unit operating point calculating section serves as a unit wherein when there is the absence of a transition in a gear shift stage from a low speed gear ratio to a high speed gear ratio or from the high speed gear ratio to the low speed gear ratio in a sequence when it is assumed that the unit is operated using the calculated target unit operating point, the target unit operating point used in a previous calculation is assigned to the target value of the unit operating point.

8. A control device for a hybrid vehicle, including a unit having an internal combustion engine, a motor, a stepped power transmission and an electric storage device adapted to supply electric power output to the motor, wherein at least one of power outputs of the internal combustion engine and the motor is transmitted through the stepped power transmission to an output shaft thereof, the control device comprising:

means for detecting an SOC value indicative of a remaining charged capacity of an electric storage device;

means for calculating a target value of a running efficiency, indicative of a proportion of a given physical quantity, in terms of a drive power rate required for driving the vehicle, in such a manner that the higher the SOC value, the small will be the target value to be calculated;

means for calculating a target value of a unit operating point, that forms the target running efficiency, from among operating points of a unit which cause the drive power rate provided by an internal combustion engine to be utilized at the running efficiency with the maximum efficiency; and

target unit operating point actualizing means for controlling the unit such that the unit is operated at the target unit operating point.

9. A control method for a hybrid vehicle, including a unit having an internal combustion engine, a motor, a stepped power transmission and an electric storage device adapted to supply electric power output to the motor, wherein at least one of power outputs of the internal combustion engine and the motor is transmitted through the stepped power transmission to an output shaft thereof, the control method comprising:

detecting an SOC value indicative of a remaining charged capacity of the electric storage device;

calculating a target value of a running efficiency, indicative of a proportion of a given physical quantity in terms of a drive power rate required for driving the vehicle in such a manner that the higher the SOC value, the small will be the target value to be calculated;

calculating a target value of a unit operating point, that forms the target running efficiency, from among operating points of the unit which cause a power rate provided by the internal combustion engine to be utilized at the running efficiency with the maximum efficiency; and

controlling the unit in a way to actualize operation of the unit at the target unit operating point.