Dynamic deceleration control for hybrid vehicle to achieve a consistent overrun response

Patent metadata

Field	Value
Publication number	US-9932027-B2
Application number	US-201414908242-A
Country	US
Kind code	B2
Filing date	Aug 21, 2014
Priority date	Aug 21, 2013
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

A hybrid electric vehicle is capable of direct drive by internal combustion engine, electric motor, or both. In order to provide a consistent overrun response, a torque controller determines an appropriate deceleration characteristic according to, for example, transmission speed ratio, vehicle gradient and vehicle mass, and commands the electric motor and the engine to contribute a negative torque which meets the required deceleration characteristic. A ‘tip’ function modifies the characteristic in the event of a change commanded by the vehicle driver, for example a change of speed ratio.

First claim

The invention claimed is:

1. A method of obtaining a consistent overrun response of a hybrid electric vehicle capable of direct drive by internal combustion engine, electric motor, or a combination thereof, said electric motor being capable of operation as a generator, said method comprising:
determining a target deceleration by reference to one or more of vehicle speed, transmission speed ratio, gradient, vehicle mass and vehicle mode;
measuring real-time vehicle deceleration;
continually determining a difference between said target deceleration and said real-time deceleration;
commanding said internal combustion engine and/or electric motor to provide said difference by generating a negative torque;
identifying a downshift of transmission speed ratio;
modifying said target deceleration by reference to the downshifted transmission ratio; and
smoothing a transition to the modified target deceleration.

2. The method of claim 1 , wherein said difference between said target deceleration and said real-time deceleration is provided by said electric motor.

3. The method of claim 1 , wherein said difference between said target deceleration and said real-time deceleration is provided by said internal combustion engine operating in a mode in which a fuel supply is cut-off.

4. The method of claim 3 , wherein said internal combustion engine is adapted to supply the negative torque via a clutch, and said clutch is slipped to vary a negative torque output thereof.

5. The method of claim 1 , wherein said transition is completed within a pre-determined time period.

6. The method of claim 5 , wherein the modified target deceleration is determined in an event of a driver request of transmission downshift.

7. The method of claim 1 , further comprising a preparatory step of detecting a substantially zero movement of an accelerator pedal to implement a requirement for an overrun response.

8. The method of claim 1 , further comprising determining an estimate of negative torque to achieve a target deceleration, applying said estimate as an initial command to said internal combustion engine and electric motor, and thereafter continually determining said difference and commanding said internal combustion engine and/or electric motor to provide said difference.

9. The method of claim 1 , further comprising:
continually monitoring gradient,
detecting a change of gradient exceeding a gradient threshold, and
adjusting said target deceleration according to a gradient change exceeding a gradient threshold.

10. A torque controller of a hybrid electric vehicle, said torque controller comprising a processor and a memory having a plurality of deceleration characteristics for said vehicle, and said processor being adapted to implement the method of claim 1 .

11. A hybrid electric vehicle capable of direct drive by internal combustion engine, electric motor or a combination thereof, said vehicle being adapted to implement the method of claim 1 .

Assignees

• Jaguar Land Rover Ltd

Inventors

• Liggins Steve
• Message Simon
• Kirkman Richard
• Hancock Matthew

Classifications

• B60W2552/15

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• B60W20/13

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