Engine power demand load-leveling for a hybrid electric vehicle
First Claim
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1. A method for a vehicle having an engine, a battery, and a controller, comprising:
- computing available battery power constraints using the controller;
computing a filter constant using the controller that changes within the battery power constraints as a function of a difference between driver demand for power and road-load power; and
filtering power demand using the filter constant during steady-state vehicle operation when the driver attempts to maintain constant vehicle speed.
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Abstract
A method for controlling a demand for engine power in a control for an engine in a hybrid electric vehicle with power-split characteristics. Following transitions from acceleration or deceleration operating modes to a steady-state operating mode, power demand excursions from road-load power are attenuated or avoided by filtering the power demand using a filter constant that changes within battery power constraints as a function of a normalized driver demand for power at traction wheels for the vehicle.
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Citations
14 Claims
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1. A method for a vehicle having an engine, a battery, and a controller, comprising:
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computing available battery power constraints using the controller; computing a filter constant using the controller that changes within the battery power constraints as a function of a difference between driver demand for power and road-load power; and filtering power demand using the filter constant during steady-state vehicle operation when the driver attempts to maintain constant vehicle speed. - View Dependent Claims (2)
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3. A method for controlling an engine power demand in a hybrid electric vehicle having an engine with an electronic control unit, a generator, a motor, a battery and gearing establishing a mechanical power flow path from the engine to vehicle traction wheels and an electro-mechanical power flow path to the vehicle traction wheels, the method comprising:
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receiving in the electronic control unit a battery state-of-charge (SOC) and a driver demand for power at the traction wheels; calculating a control filter constant in the electronic control unit that is a based on road-load power; filtering the driver demand for power using the calculated control filter constant to obtain a filtered driver demand for power; calculating a battery power request within limits for the battery state-of-charge; and computing an engine power demand as a function of the filtered driver demand for power and the battery power request. - View Dependent Claims (4, 5)
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6. A method for controlling an engine power demand in a hybrid electric vehicle having an engine with an electronic control unit, a generator, a motor, a battery and gearing establishing a mechanical power flow path from the engine to vehicle traction wheels and an electro-mechanical power flow path to the vehicle traction wheels, the method comprising:
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calculating a control filter constant in the electronic control unit that is a function of road-load power; filtering a driver demand for power in the electronic control unit using the calculated control filter constant to obtain a filtered driver demand for power; computing a maximum power for filtering the driver demand for power at the traction wheels during a steady-state vehicle operating mode; calculating a battery power request within limits for a battery state-of-charge; and computing an engine power demand as a function of the filtered driver demand for power and the battery power request to attenuate excursions of a driver demand for power to improve engine response to vehicle acceleration and deceleration requests and to reduce engine speed variations during a steady-state vehicle operating mode. - View Dependent Claims (7, 8, 9)
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10. A method for controlling an engine power demand in a hybrid electric vehicle having an engine with an electronic control unit, a generator, a motor, a battery and gearing establishing a mechanical power flow path from the engine to vehicle traction wheels and an electro-mechanical power flow path to the vehicle traction wheels, the method comprising:
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receiving a battery state of charge (SOC) and a driver demand for power at the traction wheels within the electronic control unit; calculating a control filter constant based on road-load power; filtering the driver demand for power in the electronic control unit using the calculated control filter constant to obtain a filtered driver demand for power; computing, within a limit for battery state-of-charge, a maximum power for filtering the driver demand for power at the traction wheels during a steady-state vehicle operating mode; computing, within a limit for battery state-of-charge, a minimum power for filtering the driver demand for power at the wheels during the steady-state vehicle operating mode; the maximum power for filtering and the minimum power for filtering being respectively greater and less than the road-load power at a given instant in the steady-state operating mode; calculating a battery power request; and computing an engine power demand based on the filtered driver demand for power and the battery power request. - View Dependent Claims (11, 12)
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13. A hybrid vehicle comprising:
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an engine; a traction battery; and a controller configured to control engine power by filtering driver power demand using a filter constant that changes within available traction battery power constraints based on a difference between driver demand for power and road-load power during steady-state vehicle operation while a driver attempts to maintain constant vehicle speed.
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14. A hybrid vehicle having an engine, a motor, and a traction battery, comprising:
a microprocessor-based controller configured to control the engine in response to a driver power demand filtered using a filter constant that is a normalized function of a difference between driver power demand and road load during steady-state vehicle operation when power demand is less than a maximum power demand and greater than a minimum power demand.
Specification