System and method for controlling the transient torque output of a variable displacement internal combustion engine

• US 5,437,253 A
• Filed: 08/31/1994
• Issued: 08/01/1995
• Est. Priority Date: 12/23/1993
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Robichaux, Jerry D., Huffmaster, Roger L.
• Primary Examiner(s): WOLFE JR, WILLIS RAY
• Application Number:
  US08/298,694
• Time in Patent Office: 335 Days
• Field of Search: 123/396, 123/399, 123/361, 123/403, 123/416, 123/417, 123/419, 123/422, 123/423, 123/436, 123/478, 123/481, 123/198 F
• US Class Current: 123/399
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2250/21 during a transition between engine operation modes or states
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02F 2007/0092 Transparent materials
• CPC Class Codes: F02P 5/045 combined with electronic control of other engine functions, e.g. fuel injection in general F02D37/02
• CPC Class Codes: F02P 5/1504 with particular means during a transient phase, e.g. acceleration, deceleration, gear change during starting F02P5/1506
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A system for controlling the transient torque output of a multicylinder, variable displacement, spark-ignited, fuel injected automotive internal combustion engine during periods when the effective displacement of the engine is being changed includes a spark timing controller, a throttle controller for positioning an intake air throttle, an engine cylinder operator for deactivating and reactivating at least some of the engine'"'"'s cylinders, and an engine controller having a processor for selecting the number of cylinders for operation and for operating the spark timing controller, the throttle controller, and the cylinder operator so that during any transition from operation with a first number of activated cylinders to operation with a second number of activated cylinders, the processor will alter the spark advance and control the amount of air entering the engine cylinders so that the torque output of the engine will remain relatively unchanged during the transition.

Claims

1. A system for controlling the transient torque output of a multicylinder, variable displacement, spark-ignited, fuel injected automotive internal combustion engine during periods when the effective displacement of the engine is being changed, said system comprising:

a spark timing controller;

a throttle controller for positioning an intake air throttle;

an engine cylinder operator means for deactivating and reactivating at least some of said cylinders;

an engine controller having a processor for selecting the number of cylinders for operation and for operating said spark timing controller, said throttle controller, and said cylinder operator means such that during any transition from operation with a first number of activated cylinders to operation with a second number of activated cylinders, the processor will alter the spark advance and control the amount of air entering the engine cylinders so that the torque output of the engine will remain relatively unchanged during such transition.

2. A system according to Claim 1, wherein said processor commands said throttle to approximately its wide-open position during at least part of transitions from a state of operation of a greater number of activated cylinders to a lesser number of activated cylinders, with said processor commanding the throttle to approximately its closed position during at least part of transitions from a state of operation of a lesser number of activated cylinders to a greater number of activated cylinders.

3. A system according to claim 2, wherein said processor commands said spark timing controller to retard the spark advance during said transitions.

4. A system according to claim 2, wherein said processor maintains said throttle in approximately a closed position during transitions from operation at a lesser number of cylinders to operation at a greater number of cylinders for a time sufficient to allow pressure within the intake manifold to rapidly decay to the pressure at which the engine will have substantially the same torque output with the number of cylinders in operation after the transition as it had with a different number of cylinders prior to the transition.

5. A system according to claim 2, wherein said processor maintains said throttle in approximately an open position during transitions from operation at a greater number of cylinders to operation at a lesser number of cylinders for a time sufficient to allow pressure within the intake manifold to increase to the pressure at which the engine will have substantially the same torque output with the number of cylinders in operation after the transition as it had with a different number of cylinders prior to the transition.

6. A system according to claim 2, wherein said engine has eight cylinders and said processor commands the throttle to approximately its closed position for an amount of time approximately equivalent to a predetermined number of crankshaft revolutions when the engine transitions from a state of operation with less than eight cylinders to operation with eight cylinders.

7. A system according to claim 2, wherein said engine has eight cylinders and said processor commands the throttle to its wide open position for an amount of time approximately equivalent to a predetermined number of crankshaft revolutions when the engine transitions from a state of operation with less than eight cylinders to operation with four cylinders.

8. A system according to claim 1, wherein said processor commands said spark timing controller to retard the spark advance whenever the engine changes the number of activated cylinders.

9. A system according to claim 8, wherein said processor commands said spark timing controller to retard the spark advance to a point which is less than the minimum advance for best torque, with the spark being retarded by an amount proportional to the degree to which the air charge within the activated cylinders exceeds the desired steady state air charge for the instantaneous number of cylinders operating.

10. A system according to claim 8, wherein said processor commands said spark timing controller to retard the spark with an initial step decrease in spark advance, followed by gradual advance of the spark timing to a point approximating MBT during transitions from operation with a lesser number of cylinders to operation with a greater number of cylinders.

11. A system according to claim 8, wherein said processor commands said spark timing controller to gradually retard the spark followed by a step advance of the spark timing to a point approximating MBT during transitions from operation with a greater number of cylinders to operation with a lesser number of cylinders.

12. A system according to claim 8, wherein said processor tracks the number of cylinders actually in operation, and commands the spark controller to retard the spark advance to a point which is less than the minimum timing advance for best torque, with the spark being retarded by an amount proportional to the degree to which the air charge within the activated cylinders exceeds the desired steady state air charge for the instantaneous number of cylinders operating.

13. A method for controlling the torque output of a multicylinder, variable displacement, spark-ignited, fuel injected, automotive internal combustion engine during changes in the effective displacement, comprising the steps of:

commanding a cylinder operator to change the number of activated cylinders;

controlling the spark advance so as to temporarily limit the torque capability of the engine during at least part of the transition to operation with the new number of cylinders; and

controlling the flow of air into the engine cylinders such that the amount of air admitted into the activated cylinders after the transition corresponds to the torque output of the engine prior to the transition.

14. A method according to claim 13, wherein the spark advance is retarded from the point of minimum advance for best torque with the number of activated cylinders prior to completion of the transition.

15. A method according to claim 14, wherein the spark is retarded by an amount which is proportional to the degree to which the air charge within cylinders which have been activated prior to a transition either exceeds or is less than the air charge within the cylinders which remain activated after the transition.