System and method to provide lubrication for a plug-in hybrid

Patent metadata

Field	Value
Publication number	US-9855833-B2
Application number	US-48885809-A
Country	US
Kind code	B2
Filing date	Jun 22, 2009
Priority date	Jun 22, 2009
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

In hybrid electric vehicles having increased battery storage capacity and plug-in capability, electric-only operation of significant duration is available. To supplement lubrication for the electric and mechanical component provided by an engine-driven mechanical pump, an electric pump is provided in parallel to the mechanical pump. A method to control the electric pump is also disclosed in which a first desired quantity of a first component and a second desired quantity of a second component are determined. The electric pump is commanded to provide the greater of the first and second quantities. The desired quantity can be based on preventing temperature in the component from exceeding a maximum design temperature and/or providing sufficient lubrication to rotating parts of the component.

First claim

What is claimed:

1. A method comprising:
controlling speed of an electric pump coupled to a lubricating oil circuit of a transmission and an electric motor in response to a desired fluid flow based on a greater of a first oil quantity to provide lubrication to the transmission and a second oil quantity based on temperature of the electric motor as determined from resistance of motor windings to cool the electric motor when a mechanical pump is inactive.

2. The method of claim 1 , the method further comprising:
determining a mechanical pump output quantity when the mechanical pump is operating;
turning off the electric pump when the mechanical pump output quantity is greater than the greater of the first and second quantities; and
commanding the electric pump to provide a shortfall quantity when the mechanical pump output quantity is less than the greater of the first and second quantities, the shortfall quantity being the greater of the first and second quantities less the mechanical pump output quantity.

3. The method of claim 1 wherein the first and second quantities are first and second flow rates.

4. The method of claim 1 wherein the pump, transmission, and electric pump are disposed in a hybrid electric vehicle (HEV).

5. The method of claim 1 wherein the temperature is determined based on:
Tref+(1/α) (R/Rref−1), where Rref is a reference resistance measured at Tref, a reference temperature, R is the measured resistance, and α is a change in resistance per degree temperature change.

6. The method of claim 5 wherein α is a constant which depends on the material of the windings in the motor.

7. A method to provide lubricant flow to a fluid circuit having a first component and an electric motor, comprising:
commanding an electric pump coupled to the fluid circuit to continuously increase flow to the fluid circuit until a lubricant quantity provided to the first component satisfies a desired lubricant quantity and a temperature in the electric motor satisfies a predetermined threshold temperature, the temperature being estimated using measured resistance of windings in the electric motor.

8. The method of claim 7 wherein a second component is fluidly coupled to the fluid circuit and the commanding is further based on a temperature in the second component satisfying a predetermined maximum temperature.

9. The method of claim 7 wherein a second component is fluidly coupled to the fluid circuit and the commanding is further based on a lubricant quantity being provided to the second component satisfying a threshold lubricant quantity.

10. The method of claim 7 wherein the first component is a transmission.

11. The method of claim 7 , further comprising: commanding the electric pump to continuously decrease flow to the fluid circuit in response to the lubricant quantity provided to the first component being greater than the desired lubricant quantity and the temperature in the electric motor being less than the predetermined threshold temperature.

12. The method of claim 7 wherein a mechanical pump is fluidly coupled to the fluid circuit, the method further comprising:
commanding the electric pump to turn off when:
the lubricant quantity provided to the first component by the mechanical pump is greater than the desired lubricant quantity; and
the temperature in the electric motor is less than the predetermined threshold temperature.

13. A hybrid electric vehicle system comprising:
an internal combustion engine;
a transaxle coupled to the internal combustion engine via an engine output shaft, the transaxle comprising:
a transmission;
an electric motor;
a fluid circuit, the fluid circuit providing fluid to the transmission and the electric motor, the fluid circuit further comprising:
a mechanical pump driven by a pump gear coupled to the engine output shaft; and
an electric pump, wherein the electric pump and the mechanical pump are arranged in parallel in the fluid circuit;

and
an electronic control unit electronically coupled to the electric pump, the internal combustion engine, and the electric motor, the electronic control unit commanding the electric pump to continuously increase electric pump speed in response to the mechanical pump being inactive and at least one of: a lubricant quantity provided to the transmission being less than a desired lubricant quantity and a temperature in the electric motor being greater than a predetermined threshold temperature, the temperature being determined based on resistance of windings in the electric motor.

14. The hybrid electric vehicle of claim 13 wherein the electric motor is one of:
a generator motor coupled to a sun gear of the transmission; and
a traction motor coupled in a driving relationship with a ring gear of the transmission via a reduction gear.

Assignees

• Gale Allan Roy
• Degner Michael W
• Momcilovich Paul Theodore
• Ford Global Tech Llc

Inventors

• Gale Allan Roy
• Degner Michael W
• Momcilovich Paul Theodore

Classifications

• B60W2510/087

  Temperature · CPC title

• Y02T10/6269

  Cross-Sectional Technologies · mapped topic

• F04B49/065

  and making use of computers · CPC title

• F16H2037/0866

  Power-split transmissions with distributing differentials, with the output of the CVT connected or connectable to the output shaft · CPC title

• B60L2240/425

  Temperature · CPC title