Engine control system for hybrid vehicle

• US 5,939,794 A
• Filed: 07/25/1996
• Issued: 08/17/1999
• Est. Priority Date: 07/25/1995
• Status: Expired due to Fees

• Current Assignee: Nippon Soken, Inc.
• Original Assignee: Nippon Soken, Inc.
• Inventors: Inagaki, Mitsuo, Asa, Hironori, Onimaru, Sadahisa, Sakai, Shoji
• Primary Examiner(s): Enad, Elvin G.
• Application Number:
  US08/686,389
• Time in Patent Office: 1,118 Days
• Field of Search: 290/40 D, 290/40 B, 290/40 C, 318/139, 322/16, 322/29, 180/65.2, 180/243
• US Class Current: 290/40.00A
• 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 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/12 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 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 2710/1061 Output power
• 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 10/92 : Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/917 : with transmission for changing gear ratio
• CPC Class Codes: Y10S 903/918 : Continuously variable

Abstract

A series hybrid vehicle includes a generator to be driven by an engine, a battery to be charged by the output power of the generator, and a motor for driving the vehicle using the output power sent from the generator and the output power sent from the battery. In an engine control system for the series hybrid vehicle, the values of power demanded by the vehicle when the vehicle is running (i.e., power demand values) are derived based on various engine operation indicative sensor signals, and a running state of the vehicle is estimated based on a frequency distribution of the power demand and a mean value of such power demand values. The system selects one of prestored control patterns depending on the estimated vehicle running state and controls the engine based on the selected control pattern so as to further control the output power of the generator. The system is also applicable to a parallel hybrid vehicle.

Claims

1. An engine control system for a hybrid vehicle having an engine, a motor and a power storage unit for supplying power to said motor, said system comprising:

a plurality of prestored engine operation command patterns;

deriving means for (A) deriving a representation of the operating state of the vehicle from a plurality of power demand values and (B) outputting the representation of the operating state of the vehicle; and

control means for (C) selecting one of said prestored engine operation command patterns according to the representation of the operating state of the vehicle and (D) adjusting an operation of the engine based on said selected pattern;

wherein each of the power demand values is derived from a sensor signal indicating an operating condition of the vehicle that has arisen during the period of time for which the vehicle has been continuously running; and

wherein the representation of the operating state of the vehicle outputted by said deriving means is based on at least a frequency distribution of the power demand values.

2. The engine control system according to claim 1, wherein the vehicle is a series hybrid vehicle having a generator driven by said engine and wherein said power storage unit is charged by an output power of said generator and said motor is driven by the output power of said generator and an output power of said power storage unit.

3. The engine control system according to claim 1, wherein the vehicle is a series hybrid vehicle having a generator driven by said engine and wherein said power storage unit is charged by an output power of said generator and said motor is driven by the output power of said generator and an output power of said power storage unit.

4. The engine control system according to claim 1, wherein said control means adjusts the speed of the engine.

5. The engine control system according to claim 1, wherein the 20 vehicle is a parallel hybrid vehicle in which said engine is mechanically coupled to driven wheels.

6. The engine control system according to claim 1, wherein the vehicle is a parallel hybrid vehicle in which said engine is mechanically coupled to driven wheels.

7. The engine control system according to claim 1, wherein said control means adjusts an output of the engine.

8. An engine control system according to claim 1, wherein said control means adjusts the power output of the engine.

9. An engine control system according to claim 1, at least one of the power demand values being derived from one among a speed signal, an acceleration signal, and a braking signal.

10. An engine control system according to claim 1, at least two of the power demand values each being derived from one among a speed signal, an acceleration signal, and a braking signal.

11. An engine control system according to claim 1, said representation being further based on a mean value of the power demand values over a predetermined period of time.

12. An engine control system according to claim 1, wherein said plurality of prestored engine operation command patterns comprises:

a first pattern in which the operation of said engine is periodically adjusted while the vehicle is running; and

a second pattern in which the operation of said engine is not adjusted;

wherein said control means selects said first pattern when a degree of variation among the power demand values exceeds a predetermined threshold, and said control means selects said second pattern when the degree of variation among the power demand values is below the predetermined threshold.

13. An engine control system according to claim 1, at least one of the power demand values being derived from one among a speed signal, an acceleration signal, and a braking signal.

14. An engine control system according to claim 1, at least two of the power demand values each being derived from one among a speed signal, an acceleration signal, and a braking signal.

15. An engine control system according to claim 1, said representation being further based on a mean value of the power demand values over a predetermined period of time.

16. An engine control system according to claim 1, at least one of the power demand values being derived from one among a speed signal, an acceleration signal, and a braking signal.

17. An engine control system according to claim 1, at least two of the power demand values each being derived from one among a speed signal, an acceleration signal, and a braking signal.