Optimizing the automatic engine start/stop mechanism for driving operation

Patent metadata

Field	Value
Publication number	US-9926902-B2
Application number	US-201615293727-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Oct 14, 2015
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

A system and method for starting/stopping an engine in a moving vehicle include stopping the engine, by a controller, in response to a time needed to start the engine from a stopped state and attain an engine speed corresponding to a driveshaft speed when stopping the engine being less than a target time, and starting the engine in response to the time needed reaching the target time. A start/stop vehicle having an engine includes a driveshaft speed sensor and a controller configured to stop the engine while the vehicle is moving with a vehicle speed below a threshold speed in response to a time associated with starting the engine and powering a driveshaft to attain a driveshaft speed measured by the driveshaft speed sensor and stored from a previous engine stopping event being less than a threshold time.

First claim

What is claimed is:

1. A start/stop vehicle having an engine, comprising:
a driveshaft speed sensor; and
a controller configured to stop the engine while the vehicle is moving with a vehicle speed below a threshold speed in response to a time associated with starting the engine and attaining an engine speed corresponding to a driveshaft speed measured by the driveshaft speed sensor and stored from a previous engine stopping event being less than a threshold time.

2. The vehicle of claim 1 further comprising a starter motor, wherein the controller is further configured to operate the starter motor to start the engine if the engine is in a stopped state and the time associated with starting the engine and powering the driveshaft to attain the driveshaft speed reaches the threshold time.

3. The vehicle of claim 1 further comprising a transmission, the controller further configured to determine the time associated with starting the engine and powering the driveshaft based on a transmission gear when the engine was stopped and a current transmission gear.

4. The vehicle of claim 1 wherein the controller is further configured to start the engine in response to receiving one or more signals associated with: a clutch release, actuation of an accelerator pedal, or a brake pedal release.

5. The vehicle of claim 1 wherein the controller is further configured to stop the engine in response to detecting a gear shift to a lower gear while vehicle speed is decreasing.

6. The vehicle of claim 1 wherein the controller is further configured to signal a recommended gear based on current vehicle speed to minimize the driveshaft speed.

7. A method for starting/stopping an engine in a moving vehicle, comprising:
stopping the engine, by a controller, in response to
a time needed to start the engine from a stopped state and attain an engine speed corresponding to a driveshaft speed when stopping the engine being less than a target time; and
starting the engine in response to the time needed reaching the target time.

8. The method of claim 7 wherein the time needed increases with increasing driveshaft speed.

9. The method of claim 8 further comprising determining the time needed to start the engine from a stopped state and attain an engine speed corresponding to a driveshaft speed when stopping the engine based on a currently engaged gear of a vehicle transmission and current velocity of the vehicle.

10. The method of claim 7 further comprising:
detecting a transmission neutral position to indicate a gear shift after stopping the engine.

11. The method of claim 7 further comprising:
detecting a gear shift in response to a transmission gear lever parity check between a gear selected upon stopping the engine and a current gear.

12. The method of claim 7 further comprising accessing a stored relationship between driveshaft speed and vehicle speed to determine the engine speed to attain the driveshaft speed after starting the engine based on the vehicle speed and a currently selected gear.

13. The method of claim 7 further comprising starting the engine in response to receiving one or more signals associated with
a clutch release,
actuation of an accelerator pedal,
actuation of a gear shift, or
a brake pedal release.

14. The method of claim 7 further comprising:
preventing stopping the engine in response to vehicle speed exceeding a corresponding threshold.

15. The method of claim 7 further comprising stopping the engine in response to decreasing vehicle speed and a gear shift being in a neutral position.

16. The method of claim 7 further comprising stopping the engine in response to a brake request while vehicle speed is decreasing.

17. The method of claim 7 further comprising signaling a recommended gear based on current vehicle speed to minimize the driveshaft speed.

18. A method for controlling an engine of a start/stop vehicle, comprising:
while the vehicle is moving below a speed threshold, when a time for starting the engine and reaching an engine speed corresponding to a current driveshaft speed is less than a time threshold, storing the current driveshaft speed and stopping the engine; and
starting the engine and attaining the engine speed corresponding to the stored driveshaft speed in response to a driver power demand.

19. The method of claim 18 wherein the driver power demand corresponds to at least one signal indicative of a brake pedal release, an accelerator pedal actuation, or a clutch pedal release.

20. The method of claim 18 further comprising determining the engine speed based on a currently selected gear different from a gear selected when stopping the engine.

Assignees

• Ford Global Tech Llc

Inventors

• Crisp Nicholas Dashwood
• Busch Rainer

Classifications

• F02N2300/2011

  Control involving a delay; Control involving a waiting period before engine stop or engine start · CPC title

• B60Y2300/18016

  Start-stop drive, e.g. in a traffic jam · CPC title

• F02N11/0833 Primary

  Vehicle conditions (F02N11/0822, F02N11/0825 take precedence) · CPC title

• F16H63/50

  Signals to an engine or motor · CPC title

• F02N2200/0802

  Transmission state, e.g. gear ratio or neutral state · CPC title