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US 2019/0316530 A1Published application
System and method for variable compression ratio engine
AssigneeFord Global Technologies, LLC
InventorsThomas G. Leone, Michael Howard Shelby, Lyth Alobiedat
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Abstract
Methods and systems are provided for improving calibration of a variable compression ratio engine. Cylinder-to-cylinder compression ratio variations are detected and accounted for by comparing cylinder fuel flow and IMEP at each compression ratio setting. Dilution parameters including EGR and VCT schedule are also calibrated to account for the cylinder-to-cylinder compression ratio variations.
Claims20
A method for an engine, comprising:
- updating a nominal calibration schedule for actuating a variable compression ratio (VCR) mechanism of an engine based on each of fuel flow and peak torque of each cylinder of the engine at each compression ratio setting of the (VCR) mechanism;
- actuating the VCR mechanism based on the updated calibration schedule;
- and
- adjusting an exhaust gas recirculation (EGR) flow to the engine responsive to the actuation.
1 more element
A method, comprising:
- comparing a target compression ratio for an engine with an actual compression ratio of each cylinder of the engine;
- computing a fuel penalty associated with the target compression ratio based on an aggregated difference between the actual compression ratio of each cylinder of the engine and the target compression ratio;
- transitioning to a lower compression ratio if the fuel penalty exceeds a threshold;
- and
- selectively adjusting an EGR flow to the engine based on the actual compression ratio of a cylinder having a highest difference between actual compression ratio and commanded compression ratio, wherein the actual compression ratio is lower than the commanded compression ratio.
2 more elements
An engine system, comprising:
- an engine including a plurality of cylinders;
- a variable compression ratio (VCR) mechanism coupled to a piston of each cylinder of the plurality of cylinder for applying one of a plurality of compression ratio settings in a given cylinder via mechanical alteration of a piston position within the given cylinder;
- an exhaust gas recirculation (EGR) passage including an EGR valve for recirculating exhaust gas from an engine exhaust to an engine intake;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- updating a compression ratio calibration of the engine based on each of fuel flow and peak torque of each cylinder at each of the plurality of compression ratio settings;
- actuating the variable compression ratio mechanism of an engine to mechanically adjust a target compression ratio of the engine in accordance with the updated compression ratio calibration;
- and
- actuating the EGR valve to adjust EGR flow to the engine based on the updated compression ratio calibration when engine load is higher than a threshold load.
6 more elements
Dependencies are inferred from the claim text.