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Method and system for cylinder compression diagnostics

  • US 9,188,505 B2
  • Filed: 06/21/2013
  • Issued: 11/17/2015
  • Est. Priority Date: 06/21/2013
  • Status: Active Grant
First Claim
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1. A method for a hybrid vehicle comprising:

  • spinning an engine unfueled using motor torque with intake valve timing advanced and an intake throttle open;

    based on a change in battery current during the spinning, indicating cylinder compression degradation; and

    wherein the spinning is only performed when engine temperature is within a limit and a request has been received by the vehicle for compression testing.

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