Method for increasing electric operation in hybrid electric vehicles

Patent metadata

Field	Value
Publication number	US-9932914-B2
Application number	US-201514685659-A
Country	US
Kind code	B2
Filing date	Apr 14, 2015
Priority date	Apr 14, 2015
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

A hybrid electric vehicle includes an internal combustion engine configured to provide power to traction wheels, and a controller. The controller is configured to, in response to the engine being off and a power request exceeding an engine-start threshold, delay an engine start when vehicle speed is below a predetermined value. Delaying an engine start may include providing an engine-start-threshold offset. The offset decreases as vehicle speed increases. The engine is started when the power request exceeds a sum of the engine-start threshold and the engine-start-threshold offset.

First claim

What is claimed is:

1. A hybrid electric vehicle comprising:
an internal combustion engine configured to provide power to traction wheels; and
a controller configured to, in response to the engine being off and a power request exceeding an engine-start threshold, modify the engine-start threshold as a function of vehicle speed by providing an engine-start-threshold offset that decreases as vehicle speed increases, and starting the engine when the power request exceeds a sum of the threshold and the offset.

2. The vehicle of claim 1 , wherein the engine-start-threshold offset has a maximum value based on a battery-discharge limit.

3. The vehicle of claim 1 , wherein the engine-start-threshold offset is based on the vehicle speed and the engine-start threshold.

4. The vehicle of claim 3 , wherein the engine-start-threshold offset is obtained from a lookup table.

5. The vehicle of claim 1 , wherein the controller is configured to delay the engine start in response to the engine being off, the power request exceeding the engine-start threshold, and a battery state of charge (SOC) exceeding an SOC threshold.

6. A method of controlling a hybrid electric vehicle having an internal combustion engine, the method comprising:
in response to the engine being off, a first driver power request exceeding an engine-start threshold and current vehicle speed being above a predetermined value, starting the engine; and
modifying the engine-start threshold by a magnitude that is based on the vehicle speed; and
in response to the engine being off and a second driver power request exceeding the engine-start threshold but being less than the modified engine-start threshold, delaying an engine start event;
wherein delaying an engine start event comprises providing an engine-start-threshold offset, the offset decreasing as vehicle speed increases, and starting the engine when the power request exceeds a sum of the engine-start threshold and the engine-start-threshold offset.

7. The method of claim 6 , wherein the engine-start-threshold offset has a maximum value based on a battery-discharge limit.

8. The method of claim 6 , wherein the engine-start-threshold offset is based on the current vehicle speed and the engine-start threshold.

9. The method of claim 8 , wherein the engine-start-threshold offset is obtained from a lookup table.

10. The method of claim 6 , further comprising in response to the engine being off, a second driver power request exceeding the engine-start threshold, current vehicle speed being below the predetermined value, and a battery state of charge being below a calibratable threshold, starting the engine.

11. A hybrid electric vehicle comprising:
traction wheels;
an electric machine configured to provide power to the traction wheels;
an internal combustion engine; and
a controller configured to
coordinate the electric machine and internal combustion engine to satisfy a driver power request,
start the engine in response to a driver power request exceeding an engine-start threshold, and
modify the engine-start threshold to delay an engine start event as a function of vehicle speed, including providing an engine-start-threshold offset, the offset decreasing as vehicle speed increases, and starting the engine when the power request exceeds a sum of the engine-start threshold and the engine-start-threshold offset.

12. The hybrid electric vehicle of claim 11 , wherein the engine-start-threshold offset has a maximum value based on a battery-discharge limit.

13. The hybrid electric vehicle of claim 11 , wherein the engine-start-threshold offset is based on the vehicle speed and the engine-start threshold.

Assignees

• Ford Global Tech Llc

Inventors

• Mansour Mohamad
• Okubo Shunsuke
• Okubo Carol Louise
• Bryan Paul Stephen
• Frederick Kenneth
• Cadwell Floyd

Classifications

• F02N2200/0801

  Vehicle speed · CPC title

• B60W2540/10

  Accelerator pedal position · CPC title

• B60K6/24

  characterised by the combustion engines · CPC title

• Y02T10/48

  Cross-Sectional Technologies · mapped topic

• B60W20/00

  Control systems specially adapted for hybrid vehicles {(hybrid vehicle design, B60K6/00; electric vehicles B60L)} · CPC title