CONTROL ALGORITHM FOR HYBRID ELECTRIC VEHICLE

• US 20050139400A1
• Filed: 03/08/2005
• Published: 06/30/2005
• Est. Priority Date: 05/03/2001
• Status: Active Grant

• Current Assignee: Ford Motor Company
• Original Assignee: Ford Motor Company
• Inventors: GEE, THOMAS SCOTT
• Granted Patent: US 8,342,272 B2
• Time in Patent Office: Days
• US Class Current: 180/65.235
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/445 Temperature
• 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 2510/0676 Engine temperature
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: F01P 11/16 concerning coolant temperature F01P11/20 takes precedence
• CPC Class Codes: F01P 2025/08 Temperature
• CPC Class Codes: F01P 2050/24 Hybrid vehicles
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A hybrid electric vehicle (HEV) manages engine operation in the event of an engine cooling system malfunction by operating the engine with fewer than the total number of engine cylinders, while extracting power, particularly during transient operation, from not only the engine, but also the vehicle'"'"'s traction motor and battery.

Claims

1. A hybrid electric vehicle (HEV) comprising:

a multicylinder internal combustion engine having the capability of operation with either all the cylinders or with fewer than the total number of cylinders, with said engine having a cooling system;

an electric traction motor;

a storage battery for furnishing power to the traction motor;

an engine temperature sensor;

a battery state of charge indicator;

a vehicle system controller (VSC) which operates the engine and the traction motor so as to extract power from both the engine and the traction motor in the event that the cooling system is compromised, with the VSC receiving a temperature signal from the engine temperature sensor and a state of charge signal from the battery state of charge indicator; and

an engine control unit operated by the VSC, with the engine control unit operating the engine with all of its cylinders in the event that the engine temperature is less than a predetermined maximum temperature threshold, so as to maintain the battery state of charge within a normal maximum charge limit and a normal minimum charge limit, and with the engine control unit operating the engine at a reduced power level with fewer than all of the cylinders, so as to maintain the battery state of charge between a modified maximum charge limit and a modified minimum charge limit, in the event that the engine temperature is greater than said predetermined maximum temperature threshold.

2. A hybrid electric vehicle according to claim 1, wherein said normal minimum charge limit is greater than said modified minimum charge limit.

3. A method for operating a hybrid electric vehicle, comprising the steps of:

providing driving power from both an engine operating with all of its cylinders, and from a traction motor and battery in the event that the operating temperature of the engine is less than a predetermined temperature threshold and the state of charge of the battery falls below a normal minimum charge limit; and

providing driving power from the engine operating at a reduced power level, with fewer than the maximum number of cylinders, and from the traction motor in the event that the operating temperature of the engine is greater than a predetermined threshold and the battery state of charge falls below a modified minimum charge limit.

4. A method according to claim 3, wherein said normal minimum charge limit is greater than said modified minimum charge limit.

5. A method according to claim 3, wherein said engine will be operated so as to provide driving power until such time as at least a first maximum battery charge limit is reached.

6. A method for operating a hybrid electric vehicle having a multicylinder internal combustion engine and a traction motor and traction battery, comprising the steps of:

sensing the operating temperature of the internal combustion engine;

sensing the state of charge of the traction battery; and

providing driving power simultaneously from the traction motor and the engine during transient operation, sufficient to approximate the level of power available from the engine operating with all cylinders, while operating the engine at a reduced power level with fewer than the maximum number of cylinders, in the event that the operating temperature of the engine is greater than a predetermined threshold temperature and the battery state of charge is below a calculated charge limit.

7. A method according to claim 6, wherein said calculated charge limit is a function of at least driver demand.

8. A method according to claim 6, wherein said calculated charge limit is a function of at least driver demand and air conditioning usage.