Method and system for engine control
AssigneeFord Global Technologies, LLC
InventorsKenneth James Miller, Thomas G. Leone, Douglas Raymond Martin
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for synergizing the benefits of a variable compression ratio engine in a hybrid vehicle system. A vehicle controller may hold the engine in a lower compression ratio during engine pull-ups and pull-downs, in particular when passing through a low speed region where compression bobbles can occur. During engine operation, in response to a change in driver demand, the controller may opt to switch the compression ratio or maintain a current compression ratio while smoothing a torque deficit using motor torque, the selection based on fuel economy.
Claims20
A method for a hybrid vehicle, comprising:
- shifting between propelling the vehicle via motor torque and engine torque responsive to driver demand;
- and
- during the shifting, and responsive to engine speed at or below a threshold speed, transitioning an engine to a lower compression ratio.
A method for a hybrid electric vehicle, comprising:
- propelling the vehicle via an engine at a first compression ratio selected based on driver demand;
- and
- in response to a change in driver demand, selecting between maintaining the first compression ratio and transitioning to a second, different compression ratio based on each of the change in driver demand and a battery state of charge.
A hybrid vehicle system, comprising:
- a motor powered via an energy storage system;
- an internal combustion engine including a cylinder;
- a variable compression ratio (VCR) mechanism for varying a compression ratio of the engine via mechanical alteration of a piston position within the cylinder;
- vehicle wheels propelled via one or more of motor torque and engine torque;
- a pedal position sensor for receiving an operator torque demand;
- and
- a controller with computer-readable instructions stored on non-transitory memory for:
- in response to an increase in operator torque demand received while the vehicle wheels are propelled via motor torque,
- spinning up the engine from rest, while holding the engine at a lower compression ratio until a threshold engine speed is reached, and then, transitioning the engine to a higher compression ratio;
- and
- in response to an increase in operator torque demand received while the vehicle wheels are propelled via engine torque,
- maintaining the engine at the higher compression ratio until an energy storage system state of charge is lower than a threshold, and then transitioning to the lower compression ratio.
Dependencies are inferred from the claim text.