Method of varying vehicle engine braking torque using full authority active fuel management

• US 9,777,656 B1
• Filed: 10/13/2016
• Issued: 10/03/2017
• Est. Priority Date: 10/13/2016
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Bowman, Carl B
• Primary Examiner(s): Hansen, Colby M
• Application Number:
  US15/292,672
• Time in Patent Office: 355 Days
• Field of Search: None
• CPC Class Codes: F02D 13/04 using engine as brake
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2200/501 Vehicle speed
• CPC Class Codes: F02D 2200/602 Pedal position
• CPC Class Codes: F02D 2200/604 Engine control mode selected by driver, e.g. to manually start particle filter regeneration or to select driving style
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/0225 in relation with the gear ratio or shift lever position
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: F02P 3/04 Layout of circuits
• CPC Class Codes: F16H 63/50 Signals to an engine or motor

Abstract

A method for intelligent active engine braking using full authority active fuel management based on vehicle speed and brake pedal position. The method includes determining if the tow mode of the vehicle has been selected and enables all engine cylinders to ensure maximum engine braking capacity is available. When vehicle tow mode is not selected then the method varies engine braking capacity by disabling one or more cylinders based on the vehicle speed and brake pedal position.

Claims

1. A method of varying vehicle engine braking torque using full authority active fuel management control with deceleration fuel cutoff comprising:

determining if a vehicle'"'"'s accelerator pedal position is decreasing;

determining if the transmission has upshifted to the highest gear according to shift pattern when the accelerator pedal position is decreasing;

controlling the vehicle to enter active fuel management and deceleration fuel cutoff when the transmission is in the highest gear;

detecting if vehicle tow mode has been requested;

disabling active fuel management and deceleration fuel cutoff on all engine cylinders if vehicle tow mode has been requested; and

disabling active fuel management and deceleration fuel cutoff on at least one engine cylinder based on vehicle speed and brake pedal position when vehicle tow mode has not been requested.

2. The method of claim 1 wherein determining if the vehicle is in a steady state condition further comprises determining if the vehicle is under low load.

3. The method of claim 1 wherein determining if the accelerator pedal is released further comprises using a throttle position sensor.

4. The method of claim 1 wherein determining if the accelerator pedal is released further comprises using an accelerator pedal position sensor.

5. The method of claim 1 wherein determining if the transmission is in a highest gear further comprises using a gear position sensor to detect gear position.

6. The method of claim 1 wherein determining if the transmission is in a highest gear further comprises using a message from the transmission control software.

7. The method of claim 1 wherein disabling active fuel management and deceleration fuel cutoff further comprises determining vehicle speed using a wheel speed sensor signal.

8. The method of claim 1 wherein disabling active fuel management and deceleration fuel cutoff further comprises determining vehicle speed using a crank position sensor signal.

9. The method of claim 1 wherein disabling active fuel management and deceleration fuel cutoff further comprises determining brake pedal position using a brake pedal position sensor.

10. The method of claim 1 wherein controlling further comprises cutting off fuel injectors on at least one engine cylinder.

11. The method of claim 10 wherein disabling active fuel management and deceleration fuel cutoff to at least one engine cylinder further comprises independently controlling at least one active fuel management actuator and at least one fuel injector to reactivate the at least one cylinder deactivated based on vehicle speed and brake pedal position.

12. The method of claim 1 wherein controlling further comprises deactivating operation of intake and exhaust valves.

13. The method of claim 1 wherein disabling active fuel management and deceleration fuel cutoff to at least one engine cylinder further comprises disabling a predetermined number of cylinders based on vehicle speed and brake pedal position in accordance with a look up table stored in a control module.