Electric coolant pump control strategy for hybrid electric vehicles

• US 6,607,142 B1
• Filed: 11/02/2000
• Issued: 08/19/2003
• Est. Priority Date: 11/02/2000
• Status: Expired due to Term

• Current Assignee: Ford Motor Company
• Original Assignee: Ford Motor Company
• Inventors: Peters, Mark William, Kotre, Stephen John, Boggs, David Lee
• Primary Examiner(s): Boles, Derek
• Application Number:
  US09/705,169
• Time in Patent Office: 1,020 Days
• Field of Search: 237/12.3 R, 237/12.3 B, 165/41, 165/42, 180/65.1, 180/65.2, 123/41.01, 123/41.02
• US Class Current: 237/12.30B
• CPC Class Codes: B60K 6/22 characterised by apparatus, components or means specially adapted for HEVs
• CPC Class Codes: F01P 2003/027 Cooling cylinders and cylinder heads in parallel
• CPC Class Codes: F01P 2003/028 Cooling cylinders and cylinder heads in series
• CPC Class Codes: F01P 2023/00 Signal processing; Details thereof
• CPC Class Codes: F01P 2023/08 Microprocessor; Microcomputer
• CPC Class Codes: F01P 2025/08 Temperature
• CPC Class Codes: F01P 2025/32 Engine outcoming fluid temperature
• CPC Class Codes: F01P 2025/33 Cylinder head temperature
• CPC Class Codes: F01P 2050/24 Hybrid vehicles
• CPC Class Codes: F01P 2050/30 Circuit boards
• CPC Class Codes: F01P 2060/08 Cabin heater
• CPC Class Codes: F01P 7/164 by varying pump speed
• CPC Class Codes: F01P 7/165 characterised by systems with two or more loops
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/904 Component specially adapted for hev

Abstract

This invention relates to a hybrid electric vehicle component coolant control system and method. The coolant system has an electric pump to move coolant through a closed system including engine and motor components. Such components to be cooled can include any electric motors, power electronics, engine, and transmission. The preferred embodiment controls coolant flow to the vehicle engine and motor in a single closed loop.

Vehicle components have temperature sensors that send temperature signals to an electric coolant pump duty cycle control strategy. The control strategy makes a determination of a duty cycle of the electric coolant pump as a function of the temperatures of vehicle components and orders the duty cycle of the electric pump.

In the preferred configuration, engine temperature sensors can acquire either engine coolant temperature or engine cylinder head temperature. The preferred configuration includes a heater core in the coolant flow path connected between vehicle components and the electric coolant pump return, whereby passenger heating requests are facilitated. Several coolant flow paths among the vehicle components are possible including a parallel and series configuration. The control system can also use a rolling average filter routine connected between the temperature sensor for the motor and the control strategy to determine the average temperature of the motor.

Claims

1. A system for controlling coolant flow to cool an electric traction motor and an internal combustion engine of a hybrid electric vehicle (HEV), comprising:

an electric coolant pump with an output and a return;

a closed coolant flow path connecting to the electric coolant pump output, flowing through the electric traction motor and the internal combustion engine of the HEV to be cooled, and ending at an electric coolant pump return;

the electric traction motor and the internal combustion engine having temperature sensors that send temperature signals to an electric coolant pump duty cycle controller; and

the controller establishing a duty cycle of the electric coolant pump as a function of temperatures of the electric traction motor and internal combustion engine, wherein at least one of the temperature sensors associated with the electric traction motor generates a signal that is filtered to provide a signal that is adjusted to minimize the effect of rapid excursions in temperature signals.

2. The system for controlling coolant flow to cool components of an HEV of claim 1 wherein the motor temperature is acquired by sending coolant temperature leaving the motor.

3. The system for controlling coolant flow to cool components of an HEV of claim 1 wherein a motor temperature is acquired by sensing motor winding temperature.

4. The system for controlling coolant flow to cool components of a hybrid electric vehicle of claim 1, wherein an engine temperature is acquired by sensing engine coolant temperature leaving a cylinder head.

5. The system for controlling coolant flow to cool components of a hybrid electric vehicle of claim 1 wherein the engine temperature is acquired by sensing the engine cylinder head temperature.

6. The system for controlling coolant flow to cool components of a hybrid electric vehicle of claim 1 wherein the coolant flow path is in a parallel configuration.

7. The system for controlling coolant flow to cool components of a hybrid electric vehicle of claim 1 wherein the coolant flow path is in a series configuration.

8. The system for controlling coolant flow to cool components of a hybrid electric vehicle of claim 1 wherein the coolant flow path further flows through a heater core connected between the hybrid electric vehicle components and the electric coolant pump return, whereby passenger heating requests are facilitated.

9. The system for controlling coolant flow to cool components of an HEV of claim 1 further comprising a rolling average filter routine connected between the temperature sensor for the motor and the control strategy, whereby the average temperature of the motor is acquired.

10. A method for controlling coolant flow to cool an electric traction motor and an internal combustion engine of a hybrid electric vehicle (HEV), comprising the steps of:

pumping coolant with an electric coolant pump having an output and a return;

flowing the coolant through a closed flow path to the electric coolant pump output, the electric traction motor, the internal combustion engine of the HEV to be cooled, and then returning at an electric coolant pump return;

sensing the electric traction motor temperature and the internal combustion engine temperature;

signaling the electric traction motor temperature and the internal combustion engine temperature to an electric coolant pump duty cycle controller; and

determining a duty cycle of the electric coolant pump as a function of the temperature of the electric traction motor and the internal combustion engine, wherein a rolling average of at least one temperature signal from the electric traction motor is used in determining the duty cycle of the electric coolant pump.

11. The method for controlling coolant flow to cool components of an HEV of claim 10, wherein sensing motor temperature is acquired by sensing coolant temperature leaving the motor.

12. The method for controlling coolant flow to cool components of an HEV of claim 10 wherein sensing motor temperature is acquired by sensing motor winding temperature.

13. The method for controlling coolant flow to cool components of an HEV of claim 10, wherein sensing engine temperature is acquired by sensing engine coolant temperature leaving the cylinder head.

14. The method for controlling coolant flow to cool components of an HEV of claim 10 wherein sensing engine temperature is acquired by sensing engine cylinder head temperature.

15. The method for controlling coolant flow to cool components of an HEV of claim 10 wherein flowing the coolant through a closed flow path is a parallel configuration.

16. The method for controlling coolant flow to cool components of an HEV of claim 10 wherein flowing the coolant through a closed flow path is a series configuration.

17. The method for controlling coolant flow to cool components of an HEV of claim 10 further comprising the step of flowing coolant through a heater core connected between the HEV components and the electric coolant pump return, whereby passenger heating requests are facilitated.

18. The method for controlling coolant flow to cool components of an HEV of claim 10 further comprising the step of determining a rolling average filter between the temperature sensing step for the motor and the control strategy, whereby the average temperature of the motor is acquired.