Methods for variable displacement engine diagnostics

• US 7,900,509 B2
• Filed: 08/06/2008
• Issued: 03/08/2011
• Est. Priority Date: 08/06/2008
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Feldkamp, Timothy Mark, Feldkamp, Lee Albert
• Primary Examiner(s): Caputo; Lisa M
• Assistant Examiner(s): Kirkland, III; Freddie
• Application Number:
  US12/186,723
• Publication Number:
  US 20100031738A1
• Time in Patent Office: 944 Days
• Field of Search: 731/143.1, 731/147.9
• US Class Current: 73/114.79
• CPC Class Codes: F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 19/0689 for in-cylinder direct injection
• CPC Class Codes: F02D 19/084 Blends of gasoline and alcohols, e.g. E85
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/1405 Neural network control
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: G01M 15/042 by monitoring a single specific parameter not covered by groups G01M15/06 - G01M15/12
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Various methods are described for monitoring cylinder valve deactivation in an engine, the engine including at least a cylinder valve actuator for deactivating at least a cylinder of the engine. One example method comprises indicating degradation of the valve actuator based on crankshaft acceleration.

Claims

1. A method for monitoring cylinder valve deactivation in an engine, comprising:

detecting a change in engine displacement;

establishing a current crankshaft acceleration pattern by processing a crankshaft acceleration vector in response to the change in engine displacement;

comparing the current crankshaft acceleration pattern with a predefined normal crankshaft acceleration pattern and a predefined degraded crankshaft acceleration pattern; and

indicating degradation of a cylinder valve actuator based on said comparison.

2. The method of claim 1 wherein monitoring cylinder valve deactivation includes monitoring cylinder valve deactivation following a transition between an activated and a deactivated mode of cylinder operation.

3. The method of claim 1 wherein indicating degradation of the cylinder valve actuator based on said comparison includes indicating degradation of the cylinder valve actuator based on crankshaft acceleration of a plurality of firing events.

4. The method of claim 3 wherein the plurality of firing events includes firing events during one complete engine cycle.

5. The method of claim 1 wherein the cylinder valve actuator includes a cylinder valve actuator that deactivates a plurality of cylinders.

6. The method of claim 1 where the engine includes 6 or more cylinders.

7. The method of claim 1 where the engine includes 8 or more cylinders.

8. The method of claim 3 wherein a crankshaft acceleration pattern over the plurality of firing events further identifies whether an actuator for an intake valve, an exhaust valve, or both, is degraded.

9. The method of claim 8 further comprising monitoring cylinder valve deactivation during a steady state of engine operation, the steady state of engine operation following a transition between activated and deactivated modes of cylinder operation.

10. The method of claim 9 wherein monitoring cylinder valve deactivation during the steady state of engine operation includes monitoring for the plurality of firing events over one complete engine cycle.

11. A method for monitoring cylinder valve deactivation in an engine, comprising:

recording at least an engine operating parameter and processing the at least an engine operating parameter by a neural network that has at least one sub-network for each cylinder operating mode;

during a first condition, indicating degradation of a cylinder valve actuator based on crankshaft acceleration processed by said neural network; and

during a second condition, indicating degradation of the cylinder valve actuator based on manifold air pressure processed by said neural network.

12. The method of claim 11 wherein the engine operating parameter is selected from a group consisting of engine speed, manifold air pressure, crankshaft acceleration, and air charge.

13. A method for monitoring cylinder valve deactivation in an engine, the engine including a plurality of cylinders, a first valve actuator for deactivating an intake valve for at least one of the plurality of cylinders and a second valve actuator for deactivating an exhaust valve for at least one of the plurality of cylinders, the method comprising:

monitoring crankshaft acceleration to identify degradation in valve deactivation;

creating a crankshaft acceleration vector from said monitoring of said crankshaft acceleration and establishing a current crankshaft acceleration pattern;

comparing the current crankshaft acceleration pattern with a predefined normal crankshaft acceleration pattern and a predefined degraded crankshaft acceleration pattern; and

identifying whether the degradation includes at least degradation of the first or second valve actuator based on the monitored crankshaft acceleration.

14. The method of claim 13, where the engine includes at least two banks of cylinders, the method further comprising:

when degradation is identified,

identifying a bank, and a valve type, based on the current crankshaft acceleration pattern.

15. A method for detecting an operational status of a plurality of valves in a variable displacement engine, comprising:

following a transition between operating modes of the variable displacement engine;

measuring an engine crankshaft acceleration value for a plurality of firing events;

establishing a current crankshaft acceleration pattern based on measured crankshaft acceleration of the plurality of firing events, including processing a crankshaft acceleration vector; and

inferring the operational status of the plurality of valves responsive to the established current crankshaft acceleration pattern, including comparing the current crankshaft acceleration pattern with predefined normal and predefined degraded crankshaft acceleration patterns.

16. The method of claim 15 wherein comparing the current crankshaft acceleration pattern with the predefined normal and predefined degraded crankshaft acceleration patterns includes computing a dot product between a normal crankshaft acceleration vector and a current crankshaft acceleration vector.

17. The method of claim 16 wherein comparing the current crankshaft acceleration pattern with the predefined normal and predefined degraded crankshaft acceleration patterns includes determining a root-mean-square deviation between the current crankshaft acceleration pattern and the predefined normal and predefined degraded crankshaft acceleration patterns.

18. The method of claim 17 wherein comparing the current crankshaft acceleration pattern with the predefined normal and predefined degraded crankshaft acceleration patterns includes computing a distance between a first vector associated with the current crankshaft acceleration pattern and a second vector associated with the predefined normal and predefined degraded crankshaft acceleration patterns.