Cooling System And Method For An Electric Motor

• US 20100295391A1
• Filed: 05/19/2009
• Published: 11/25/2010
• Est. Priority Date: 05/19/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Perkins, William Paul
• Granted Patent: US 8,080,909 B2
• Time in Patent Office: Days
• US Class Current: 310/64
• CPC Class Codes: B60K 2001/003 with means for cooling the electrical propulsion units
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: F28F 2210/10 Particular layout, e.g. for uniform temperature distribution
• CPC Class Codes: H02K 5/203 specially adapted for liquids, e.g. cooling jackets
• CPC Class Codes: H02K 9/197 in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator
• CPC Class Codes: H02K 9/227 Heat sinks
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

An electric motor which has a separate end cap heat exchanger, through which a liquid coolant is passed, is disclosed. In one example embodiment, the electric motor is a traction motor or motor-generator in a hybrid electric vehicle having an internal combustion engine. Additionally, in one embodiment, the heat exchanger has a low-temperature coolant loop configured to extract energy from the motor coolant. The electric motor may be installed in a variety of vehicles or other applications having greatly differing cooling requirements. By placing the heat exchanger and control componentry in the end cap, the cooling capability of the electric motor can be changed by selecting an end cap with the appropriate heat transfer characteristics and control componentry to provide the desired cooling. Consequently, a single electric motor, with a variety of end cap choices, can be used in a variety of applications.

Claims

1. An electric motor adapted to have a first coolant within the motor, the motor comprising:

an end cap attached to the motor; and

an internal heat exchanger disposed in the end cap, the internal heat exchanger having a first coolant passage.

2. The motor of claim 1, further comprising:

a first coolant loop passing through the motor, the first coolant loop coupled to the first coolant passage in the end cap.

3. The motor of claim 1, further comprising:

a shaft fluid seal disposed in the end cap;

a shaft of the motor passing through the end cap through the shaft fluid seal; and

a shaft fluid seal disposed in the end cap in the vicinity of the shaft.

4. The motor of claim 2, further comprising:

a pump disposed in the first coolant loop to circulate the first coolant through the first coolant loop.

5. The motor of claim 2 wherein said end cap further comprises:

a bypass passage parallel to the first coolant passage;

a valve coupled to the first coolant passage and the bypass passage;

a thermal sensor disposed in the first coolant loop; and

an electronic control unit coupled to the valve and the thermal sensor, the electronic control unit controlling a position of the valve based on a signal from the thermal sensor.

6. The motor of claim 1, further comprising:

a second coolant passage disposed in the internal heat exchanger; and

a second coolant loop external to the end cap, with the second coolant loop coupled to the second coolant passage.

7. The motor of claim 1, further comprising:

a second coolant passage in the heat exchanger;

a second coolant loop coupled to the second coolant passage;

an external heat exchanger coupled to the second coolant loop; and

a pump disposed in the second coolant loop.

8. The motor of claim 1 wherein the end cap is nondestructibly removable from the motor.

9. The motor of claim 1, wherein the motor is one of a motor generator and a traction motor.

10. The motor of claim 1 further comprising:

a second coolant passage in the internal heat exchanger, wherein the electric motor is disposed in an automotive vehicle, the vehicle comprising;

a heat-generating unit other than the motor;

a heat-generating unit cooling loop adapted to circulate a second coolant;

an external heat exchanger disposed in the heat-generating unit cooling loop; and

a branch off of the heat-generating unit cooling loop coupled to the second coolant passage.

11. The motor of claim 10 wherein the heat-generating unit is one of:

an internal combustion engine, a power-steering pump, a power electronics unit, a gearbox, and a transmission.

12. The motor of claim 10 wherein the second coolant is one of:

a water-based coolant, a dielectric fluid, oil, and a lubricant.

13. The motor of claim 1 further comprising:

a second coolant passage in the heat exchanger, wherein the electric motor is disposed in an automotive vehicle, the vehicle comprising;

a refrigeration unit adapted to circulate refrigerant through a refrigeration loop; and

a branch off of the refrigeration loop coupled to the second coolant passage.

14. An electric motor assembly disposed within an automotive vehicle, comprising:

an electric motor body having a stator and a rotor; and

an end cap removably attached to the motor, said end cap including;

an internal heat exchanger with a first coolant passage and a second coolant passage and a pump adapted to circulate a second coolant through the second coolant passage.

15. The motor assembly of claim 14 wherein the vehicle is a hybrid electric vehicle and the motor is one of a motor generator and a traction motor.

16. The motor assembly of claim 14 wherein the end cap further includes:

at least one temperature sensor disposed in the first coolant passage;

a valve disposed in the second coolant passage; and

an electronic control unit coupled to the at least one temperature sensor and the valve wherein the electronic control unit controls a position of the valve in response to a signal from the at least one temperature sensor.

17. The motor assembly of claim 14 wherein the end cap further includes:

at least one temperature sensor disposed in the first coolant passage;

an electronic control unit coupled to the at least one temperature sensor and the pump, the motor being an electric pump, wherein the electronic control unit controls the pump in response to a signal from the at least one temperature sensor.

18. A method to provide a cooling system for an electric motor, comprising:

providing an electric motor;

selecting an end cap with an integral heat exchanger and related thermal management components, such selected end cap based on cooling requirements of the electric motor; and

attaching the end cap to the electric motor.

19. The method of claim 18, further comprising:

determining the cooling requirements of the electric motor at its most demanding operating condition for its design duty cycle; and

computing the particular heat transfer characteristics which will provide at least as much cooling as the cooling requirement.

20. The method of claim 19 wherein the heat exchanger comprises a second coolant passage and a first coolant passage and the particular heat transfer characteristics include at least one of:

material of the end cap, an effective surface area for heat transfer between the second coolant passage and the first coolant passage, properties of a second coolant flowing in the second coolant passage during operation of the motor, and properties of a first coolant flowing in the first coolant passage during operation of the motor.