Electrically peaking hybrid system and method

• US 5,586,613 A
• Filed: 09/26/1994
• Issued: 12/24/1996
• Est. Priority Date: 04/22/1993
• Status: Expired due to Term

• Current Assignee: Texas A&M University System
• Original Assignee: Texas A&M University System
• Inventors: Ehsani, Mehrdad
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): MAR, MICHAEL Y
• Application Number:
  US08/312,438
• Time in Patent Office: 820 Days
• Field of Search: 123/352, 123/399, 290/9, 180/65.1, 180/65.2, 180/65.3, 180/65.4, 180/65.8, 318/139
• US Class Current: 180/65.23
• CPC Class Codes: B60K 17/356 having fluid or electric motor, for driving one or more wheels disposition of motor in, or adjacent to, traction wheel B60K7/00
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 2220/18 Reluctance machines
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 2050/0057 Frequency analysis, spectral techniques or transforms
• CPC Class Codes: B60W 2510/244 Charge state
• 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 903/916 with plurality of drive axles

Abstract

A series hybrid electric-combustion system is provided which includes an engine (16) operable to generate mechanical energy and translate it to a drive shaft (21). A battery (24) is included that is operable to store electrical energy and to deliver electrical energy. Also provided is a electric machine (18) mechanically coupled to engine (16) and electrically coupled to battery (24). Electric machine (18) has two modes of operations. In the first mode it translates electrical energy from battery (24) into additional mechanical energy at drive shaft (21). In the second mode of operation, electric machine (18) delivers electrical energy to battery (24) for storage. Converter (22) is also included in the system to convert the electrical energy from electric machine (18) for storage and battery (24) and also for converting electrical energy from battery (24) for use by electric machine 18. The system also includes command (12) for inputting system power requirements and controller (14) to control converter (22) and engine (16) in the modes of operation of the system.

Claims

1. A hybrid electric-combustion vehicle drive system, comprising:

an engine operable to generate mechanical energy, said engine mechanically coupled to a drive mechanism;

a battery operable to store electrical energy and to deliver electrical energy;

an electric machine mechanically coupled to said engine and said drive mechanism, and electrically coupled to said battery, said electric machine operable to translate electrical energy from said battery into additional mechanical energy at said drive mechanism in a first mode of operation and to translate mechanical energy from said engine and said drive mechanism to electrical energy and to deliver the electrical energy to charge said battery in a second mode of operation; and

a controller coupled to said engine and said electric machine operable to monitor said engine and said electric machine over a period of time, said controller being further operable to adjust the power level of said engine such that for each of a plurality of different operating conditions said engine operates at a determined average required power level of the system when said battery is a partially charged condition and to operate said engine at a power level below the determined average required power level of the system when said battery is in a fully charged condition, the first mode of operation being entered when system power requirements exceed a selected operating power level of the engine and the second mode of operation being entered when system power requirements are less than a selected operating power level of the engine, said controller being further operable to control the delivery of electrical energy from said electrical machine to said battery.

2. The system of claim 1, wherein one of said operating conditions is highway driving.

3. The system of claim 1, wherein one of said operating conditions is city driving.

4. The system of claim 1, wherein said controller includes fuzzy logic for determining said average required power level of the system.

5. A method of generating hybrid electric-combustion power in a vehicle propulsion system, comprising the steps of:

generating mechanical energy in an engine mechanically coupled to an electric machine;

translating the mechanical energy from the engine directly through the electric machine to a drive mechanism for propulsion;

translating excess mechanical energy from the engine to electrical energy with the electric machine;

translating excess mechanical energy from the drive mechanism to electrical energy with the electric machine;

translating electrical energy from a battery through the electric machine for propulsion during a first mode of operation;

delivering electrical energy from the electric machine to charge the battery in a second mode of operation;

monitoring the engine and electric machine energy over a period of time to determine the average required power level of the engine; and

adjusting the power level of the engine such that for each of a plurality of different operating conditions the engine operates at a determined average required power level of the system when the battery is in a partially charged condition and operating the engine at a power level below the determined average required power level of the system when the battery is in a fully charged condition, the first mode of operation being entered when system power requirements exceed a selected operating power level of the engine and the second mode of operation being entered when system power requirements are less than a selected operating power level of the engine, and further controlling the delivery of electrical energy from the electrical machine to the battery.

6. The method of claim 5, wherein one of the operating conditions is highway driving.

7. The method of claim 5, wherein one of the operating conditions is city driving.

8. The method of claim 5, wherein the average required power level of the system is determined through fuzzy logic rules.