Power control system for motor vehicles with a plurality of power-converting components

• US 5,788,004 A
• Filed: 02/09/1996
• Issued: 08/04/1998
• Est. Priority Date: 02/17/1995
• Status: Expired due to Term

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Krause, Jurgen, Friedmann, Siegfried, Brinz, Karl, Preis, Michael, Goetz, Georg
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US08/598,853
• Time in Patent Office: 907 Days
• Field of Search: 180/65.1, 180/65.2, 180/65.3, 180/65.4, 314/139, 314/143, 314/150, 314/161, 314/254, 363/15, 364/426.01, 364/426.041, 364/426.043, 364/431.03, 364/431.02, 364/431.01
• US Class Current: 180/65.28
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• 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 2510/244 Charge state
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 41/1406 with use of a optimisation method, e.g. iteration
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for
• CPC Class Codes: H02J 7/1446 in response to parameters of a vehicle
• 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 10/72 Electric energy management in electromobility

Abstract

In a power control system for motor vehicles with a plurality of power-converting elements as well as sensors for determining the efficiency of the individual elements, a processor determines the overall system efficiency from the efficiencies of the individual components, and calculates and adjusts a value for a parameter that influences the efficiency of at least one component to achieve an optimum total efficiency. Surplus power is used to charge an energy storage device. Preferably the parameters that influence the efficiency, whose values are adjusted to achieve an optimum total efficiency, are the power, or a parameter that is proportional to the power, that is to be delivered by a power-generating component, and/or the rpm or a parameter that is proportional to the rpm of a component.

Claims

1. Power control system for a motor vehicle having a power system with a plurality of power converting elements, comprising:

means for determining an operating efficiency for each of said power converting elements;

means for determining an overall operating efficiency for said power system as a function of determined operating efficiencies of said power converting elements;

means responsive to said determined, overall operating efficiency based on determined operating efficiencies of the power converting units, for calculating a value of at least an operating parameter for at least one of said power converting elements to achieve an optimum overall operating efficiency of said power system; and

means for iteratively adjusting said at least one operating parameter to said value which continuously achieves an optimum overall operating efficiency.

2. Power control system according to claim 1 wherein said means for calculating a value of at least one operating parameter to achieve an optimum overall operating efficiency comprises:

means for calculating said overall operating efficiency for a plurality of values of said at least one operating parameter; and

means for selecting a value of said at least one operating parameter which achieves a highest value of said overall operating efficiency.

3. Power control system according to claim 2 wherein said at least one operating parameter comprises at least one of output power and operating speed of one of said power converting elements of said power system.

4. Power control system according to claim 3 wherein said at least one operating parameter comprises output power and operating speed of one of said power converting elements of said power system.

5. Power control system according to claim 3 further comprising:

means for inputting a signal indicative of a required operating power determined by a driver of said motor vehicle; and

control means, operative when said output power exceeds said required operating power, for storing an excess portion of said output power in an energy storage device.

6. Power control system according to claim 5 wherein:

said power converting elements comprise at least a combustion engine, an electric generator driven by said engine, an electric motor and a traction battery; and

said control means causes a first portion of electric power generated by said generator, which portion corresponds to said required operating power, to drive said electric motor, and a remaining portion of said electric power to charge said battery.

7. Power control system according to claim 1 wherein said operating parameter is power, or a parameter proportional to the power, delivered by a power-generating element of said power system.

8. Power control system according to claim 1 wherein said operating parameter is a parameter proportional to rpm of an element of said power system.

9. Power control system according to claim 7 wherein:

said plurality of power converting elements comprises at least an electrical energy storage device;

output power or a parameter proportional to power generated by one of said power converting elements is composed of a power component that corresponds to a driving power requirement determined by a driver of said vehicle and an additional power component; and

the additional power component is used to charge an electrical energy storage device.

10. Power control system according to claim 9 wherein charging of the electrical energy storage device by means of the additional power component, instead of a higher power, is allowed only when a momentary charge amount is available in the electrical energy storage device which is at least as large as a defined limiting charge amount.

11. Power control system according to claim 9 wherein charging of the electrical energy storage device by means of the additional power component is allowed only when total efficiency is at least as large as a defined limiting efficiency.

12. Method of controlling a motor vehicle power system having a plurality of power converting elements, said method comprising the steps of:

determining an operating efficiency for each of said power converting elements;

determining an overall operating efficiency for said power system as a function of determined operating efficiencies of said power converting elements;

calculating a value of at least an operating parameter for at least one of said power converting elements to achieve an optimum overall operating efficiency of said power system; and

iteratively adjusting said at least one operating parameter to said value which achieves an optimum overall operating efficiency.

13. Method according to claim 12 wherein said step of calculating a value of at least one operating parameter to achieve an optimum overall operating efficiency comprises:

calculating said overall operating efficiency for a plurality of values of said at least one operating parameter; and

selecting a value of said at least one operating parameter which achieves a highest value of said overall operating efficiency.

14. Method according to claim 13 wherein said at least one operating parameter comprises at least one of output power and operating speed of one of said power converting elements of said power system.

15. Method according to claim 13 wherein said at least one operating parameter comprises output power and operating speed of one of said power converting elements of said power system.

16. Method according to claim 14 further comprising the steps of:

inputting a signal indicative of a required operating power determined by a driver of said motor vehicle; and

when said output power exceeds said required operating power, storing an excess portion of said output power in an energy storage device.

17. Method according to claim 16 wherein:

said power converting elements comprise at least a combustion engine, an electric generator driven by said engine, an electric motor and a traction battery; and

said storing step comprises causing a first portion of electric power generated by said generator, which portion corresponds to said required operating power, to drive said electric motor, and a remaining portion of said electric power to charge said battery.