System and method for controlling surge margin in a boosted engine system
AssigneeFord Global Technologies, LLC
InventorsGregory Patrick McConville, Julia Helen Buckland
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for improving surge control in a boosted engine system configured with an electric motor to provide electrical boost assistance. Tip-in and tip-out surge are addressed by increasing the opening of a compressor recirculation valve and coordinating the recirculation valve opening with adjustments to an exhaust waste-gate position and a power output by the electric motor. The adjustments enable an intake airflow to be provided that operates the compressor outside a surge region while providing a target boost pressure as operator torque demand increases or decreases.
Claims20
A method, comprising:
- responsive to an indication of surge following a tip-in or tip-out event, increasing a margin to surge while maintaining boost pressure at a level based on torque demand via adjustments to each of an output of an electric motor coupled to a compressor and an opening of a continuously variable compressor recirculation valve (CCRV), the adjustments selected based on the torque demand following the tip-in or tip-out event and further based on a state of charge (SOC) of a battery coupled to the electric motor.
A method, comprising:
- responsive to a first tip-out to boosted engine operation, opening a continuously variable compressor recirculation valve (CCRV) by a first amount while increasing a power output by an electric motor coupled to an intake compressor of a turbocharger;
- and
- responsive to a second tip-out to un-boosted engine operation, opening the CCRV by a second amount, larger than the first amount, while decreasing the power output by the electric motor, wherein during each tip-out operation, the increasing opening of the CCRV and the electric motor output are each adjusted based on a state of charge of a battery coupled to the electric motor.
A vehicle system, comprising:
- an engine;
- a turbocharger including an intake compressor coupled to an exhaust turbine via a shaft, and an electric motor coupled to the shaft for providing electric assistance to the turbocharger;
- a waste-gate including a waste-gate actuator coupled across the exhaust turbine of the turbocharger;
- a compressor bypass, including a continuously variable compressor recirculation valve (CCRV), coupled across the intake compressor of the turbocharger;
- a pressure sensor coupled to the intake system downstream of the compressor for estimating a pressure ratio across the compressor;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- estimating a margin to a surge limit of the compressor during a torque transient responsive to input from the pressure sensor;
- and
- responsive to the margin being less than a threshold,
- increasing an opening of the CCRV to increase the margin to above the threshold;
- and
- adjusting a power output by the electric motor based on a difference between actual boost pressure with the increased opening of the CCRV and a target boost pressure based on the torque transient.
Dependencies are inferred from the claim text.