Method and system for engine control
AssigneeFord Global Technologies, LLC
InventorsKenneth James Miller, Thomas G. Leone, Douglas Raymond Martin
Life of this patent
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Abstract
Methods and systems are provided for integrating a VCR engine with a CVT transmission. Responsive to a driver demand, a controller may determine whether to maintain a current compression ratio or transition to an alternate compression ratio based on the fuel economy benefit of the transition and further based on any engine limitations that may be incurred at the engine speed-load following the transition. To improve the net fuel economy benefit while addressing the engine limitation, a compression ratio transition may be combined with a CVT adjusted engine speed-load regime, while maintaining engine power output.
Claims10
A method for an engine coupled with a continuously variable transmission (CVT), comprising:
- for a power level, comparing engine efficiency at a current compression ratio to engine efficiency at a modified compression ratio with an adjusted engine speed-load;
- and
- in response to a higher than threshold improvement in the engine efficiency at the modified compression ratio with the adjusted engine speed-load, transitioning to the modified compression ratio by actuating a variable compression ratio mechanism to mechanically alter a piston position within a cylinder of the engine, and adjusting to the adjusted engine speed-load.
Dependencies are inferred from the claim text.