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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
First Claim
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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.

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