Control system for hybrid vehicle

• US 20020062183A1
• Filed: 09/21/2001
• Published: 05/23/2002
• Est. Priority Date: 09/22/2000
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Yamaguchi, Musashi, Muramoto, Itsuro, Takahashi, Nobutaka
• Granted Patent: US 6,480,767 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2260/54 Energy consumption estimation
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• 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 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2710/0644 : Engine speed
• CPC Class Codes: B60W 2710/0666 : Engine torque
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 2710/105 : Output torque
• CPC Class Codes: B60W 2710/1061 : Output power
• CPC Class Codes: F16H 61/662 : with endless flexible members
• 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 90/40 : Application of hydrogen technology to transportation, e.g. using fuel cells
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/905 : Combustion engine
• CPC Class Codes: Y10S 903/906 : Motor or generator
• CPC Class Codes: Y10S 903/908 : Fuel cell
• CPC Class Codes: Y10S 903/918 : Continuously variable

Abstract

A control system for a hybrid vehicle has a consumed electric power calculator (20), which calculates electric power consumption, and a battery state calculator (21), which calculates battery state SOC of a battery (5). Based on this battery state, a physical quantity per effective electric power calculator (25) calculates d physical quantity per effective power when electric power equal to or greater than consumed electric power is generated for various electric power consumption and electric power generation, and a threshold value calculator (22) obtains a threshold value having the same unit as that of the physical quantity per effective power using predetermined calculation for selecting operating modes of a generator and The battery. An operating mode selector (23) selects operating modes for an engine (1) and the battery (5) based on comparison between the above threshold value and the physical quantity per effective power corresponding to the consumed electric power, and a target generated electric power calculator (24) calculates target electric power generation. An electric power distribution controller (6) controls the engine (1) and the motor (3)

Claims

1. A control system for a hybrid vehicle for controlling the hybrid vehicle comprising a power apparatus consuming fuel and generating power, a battery storing electrical power, and a motor converting electrical power to mechanical power transmitted to a drive wheel of the vehicle, the control system including a detector detecting an operating condition of the vehicle, and programmed to:

calculate a required power indicating a power required to drive the vehicle, based on the operating condition of the vehicle;

calculate a first parameter indicating a ratio between a fuel consumption rate and the required power for running the power apparatus so as to generate a power equal to the required power;

set a threshold value with respect to the first parameter, based on a charging state of the battery;

run the power apparatus so as to generate a power larger than the required power when the first parameter is smaller than the threshold value, and transmit part of the power generated to the drive wheel, and store a remainder of the power generated in the battery; and

run the power apparatus so as to generate a power smaller than the required power when the first parameter is larger than the threshold value, and transmit all of the power generated to the drive wheel, and transmit part of a power stored in the battery to the drive wheel.

2. A control system for a hybrid vehicle according to claim 1, further programmed to:

run the power apparatus at an operating condition under which a second parameter coincides with the threshold value when the first parameter is smaller than the threshold value, the second parameter indicating a ratio between a fuel consumption rate and an effective power for running the power apparatus so as to generate a power larger than the required power, the effective power indicating a sum of the required power and an usable power indicating pan of the remainder of the power generated.

3. A control system for a hybrid vehicle according to claim 2, further programmed to;

calculate a charging efficiency and discharging efficiency of the battery, based on the charging state of the battery; and

calculate the usable power by multiplying the remainder of the power generated by the charging efficiency and the discharging efficiency.

4. A control system for a hybrid vehicle according to claim 1, further programmed to;

run the power apparatus at an operating condition under which a third parameter coincides with the threshold value when the first parameter is larger than the threshold value when the first parameter is larger than the threshold value, the third parameter indicating a ratio between a fuel consumption rate and the power generated.

5. A control system for a hybrid vehicle according to claim 1, further programmed to:

stop the running of the power apparatus when the first parameter is larger than the threshold value.

6. A control system for a hybrid vehicle according to claim 1, further programmed to:

run the power apparatus so as to generate a power equal to the required power when the first parameter is equal to the threshold value, and transmit all of the power generated to the drive wheel.

7. A control system for a hybrid vehicle according to claim 1, further programmed to:

gradually reduce the threshold value when actual charging stare of the battery is greater than the target charging state, and gradually increase the threshold value when the actual charging state of the battery is less than the target charging state.

8. A control system for a hybrid vehicle according to claim 1, further programmed to:

reduce the threshold value more, the greater is the actual charging state of the battery.

9. A control system for a hybrid vehicle according to claim 1, further programmed to:

compensate the threshold value with respect to a temperature of the battery.

10. A control system for a hybrid vehicle according to claim 1, wherein the power apparatus comprises an engine consuming fuel and generating mechanical power, and a generator converting mechanical power generated by the engine to electric power.

11. A control system for a hybrid vehicle according to claim 1, wherein the power apparatus comprises an engine consuming fuel and generating mechanical power, and wherein the hybrid vehicle further comprises a transmission transmitting mechanical power generated by the engine to a drive wheel of the vehicle.

12. A control system for a hybrid vehicle according to claim 1, wherein the power apparatus comprises an engine consuming fuel and generating mechanical power, and a generator converting mechanical power generated by the engine to electric power, and wherein the hybrid vehicle further comprises a transmission transmitting mechanical power generated by the engine to a drive wheel of the vehicle.

13. A control system for a hybrid vehicle according to claim 1, wherein the power apparatus is a fuel cell consuming fuel and generating electric power.