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USING VALVE TIMING TO IMPROVE ENGINE ACOUSTICS

  • US 20130291816A1
  • Filed: 05/02/2013
  • Published: 11/07/2013
  • Est. Priority Date: 05/02/2012
  • Status: Abandoned Application
First Claim
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1. A method of controlling sound of an engine having a crankshaft, a camshaft and a plurality of cylinders, each cylinder having an associated piston that is driven by the crankshaft, an associated exhaust valve, and an associated exhaust path length, wherein the respective exhaust path lengths associated with at least some of the plurality of cylinders differ and wherein at least some of the exhaust valves are driven by the camshaft, the method comprising:

  • operating an engine in a skip fire mode; and

    dynamically varying a phase of the camshaft between different exhaust events during a sequence of skip fire operation in a manner that at least partially compensates for differences in the exhaust path lengths associated with fired cylinders to thereby help suppress audible beats that would otherwise occur in the event that the camshaft phase was held substantially constant during the sequence of skip fire operation.

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