HYBRID VEHICLE IDLE AND CREEP CONTROL

• US 20150111693A1
• Filed: 10/18/2013
• Published: 04/23/2015
• Est. Priority Date: 10/18/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: WANG, Xiaoyong, YAMAZAKI, Mark Steven, LIANG, Wei, JOHRI, Rajit, McGEE, Ryan Abraham, KUANG, Ming Lang
• Granted Patent: US 10,293,810 B2
• Time in Patent Office: Days
• US Class Current: 477/5
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 2720/10 Longitudinal speed
• CPC Class Codes: B60W 30/18063 Creeping
• CPC Class Codes: B60Y 2300/143 Speed control
• CPC Class Codes: B60Y 2400/426 Hydrodynamic couplings, e.g. torque converters
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/902 Prime movers comprising electrical and internal combustion motors

Abstract

A vehicle includes an engine having a crankshaft, a transmission having an input, and a torque converter mechanically coupled to the input. The vehicle further includes an electric machine mechanically coupled to the torque converter, a clutch configured to mechanically couple the electric machine and crankshaft, and one or more controllers. The one or more controllers are programmed to, in response to the transmission being in a drive or reverse gear and a speed of the vehicle being less than a predetermined value in an absence of driver demand, control the electric machine to achieve a target speed to cause the torque converter to output torque such that the speed of the vehicle approaches a generally constant speed less than or equal to the predetermined value when the vehicle is on a generally flat grade.

Claims

1. A vehicle comprising:

an engine including a crankshaft;

a transmission having an input;

a torque converter mechanically coupled to the input;

an electric machine mechanically coupled to the torque converter;

a clutch configured to mechanically couple the electric machine and crankshaft; and

one or more controllers programmed to, in response to the transmission being in a drive or reverse gear and a speed of the vehicle being less than a predetermined value in an absence of driver demand, control the electric machine to achieve a target speed to cause the torque converter to output torque such that the speed of the vehicle approaches a generally constant speed less than or equal to the predetermined value when the vehicle is on generally flat grade.

2. The vehicle of claim 1 wherein the predetermined value is a maximum allowable vehicle creep speed.

3. The vehicle of claim 1 wherein the target speed is approximately equal to an idle speed of the engine.

4. The vehicle of claim 1 wherein the absence of driver demand is defined by a foot-off accelerator pedal condition.

5. The vehicle of claim 1 wherein the one or more controllers are further programmed to control the engine to output a target torque when the engine is on.

6. A method for controlling a vehicle comprising:

in response to a transmission being in a drive gear and vehicle speed being less than a predetermined value in an absence of driver demand, controlling an electric machine to achieve a target speed to cause a torque converter to output torque such that the vehicle speed approaches a generally constant value less than or equal to the predetermined value when the vehicle is on generally flat grade.

7. The method of claim 6 wherein the predetermined value is a maximum allowable vehicle creep speed.

8. The method of claim 6 wherein the target speed is approximately equal to an engine idle speed.

9. The method of claim 6 further comprising controlling an engine to output a target torque when the engine is on.

10. A hybrid vehicle comprising:

an engine including a crankshaft;

a transmission including an oil pump and having an input;

a torque converter mechanically coupled to the input;

an electric machine mechanically coupled to the torque converter;

a clutch configured to mechanically couple the electric machine and crankshaft; and

one or more controllers programmed to, in response to the transmission being in a neutral or park gear and the engine being off, control the electric machine to achieve a target speed less than engine idle or equal to a predetermined value in an absence of driver demand to output torque to the oil pump for control of oil pressure in the transmission.

11. The hybrid vehicle of claim 10 wherein the predetermined value is a minimum allowable vehicle idle speed.

12. The hybrid vehicle of claim 10 wherein the target speed is less than an idle speed of the engine.