Systems and methods for sensing fuel vapor pressure
First Claim
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1. A method for a vehicle, comprising:
- during an engine start after an engine has been off for at least a minimum duration, actively controlling fuel pressure in a fuel system to a vapor-liquid volume ratio greater than zero and then recording sensed fuel pressure and temperature in the fuel system, wherein actively controlling the fuel pressure comprises pulsing a fuel pump positioned within a fuel tank.
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Abstract
Systems and methods for sensing fuel vapor pressure are provided. In one example, a method for a vehicle comprises: during an engine start after the engine has been off for at least a minimum duration, actively controlling fuel pressure in the fuel system to a vapor-liquid volume ratio greater than zero and then recording sensed fuel pressure and temperature in the fuel system. In this way, the vapor pressure of a fuel at a given temperature may be accurately measured during isothermal conditions, thereby improving an estimation of fuel volatility.
44 Citations
18 Claims
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1. A method for a vehicle, comprising:
during an engine start after an engine has been off for at least a minimum duration, actively controlling fuel pressure in a fuel system to a vapor-liquid volume ratio greater than zero and then recording sensed fuel pressure and temperature in the fuel system, wherein actively controlling the fuel pressure comprises pulsing a fuel pump positioned within a fuel tank. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fuel system for an engine, comprising:
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a fuel tank containing fuel; a fuel pump positioned within the fuel tank and configured to pump the fuel to one or more fuel injectors coupled to the engine; a temperature sensor coupled to a fuel passage connecting the fuel pump to the one or more fuel injectors; a pressure sensor coupled to the fuel passage; and a controller configured with instructions stored in non-transitory memory, that when executed, cause the controller to; actively control fuel pressure in the fuel passage during an engine start after the engine has been off for at least a minimum duration, wherein actively controlling the fuel pressure comprises pulsing the fuel pump to drive the fuel pressure to a vapor-liquid volume ratio greater than zero; and record a sensed temperature from the temperature sensor and a sensed pressure from the pressure sensor. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method, comprising:
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pulsing a fuel pump responsive to an engine cold start, the fuel pump positioned within a fuel tank; and determining a fuel vapor pressure versus temperature characteristic based on fuel pressure and temperature while the fuel pump is being pulsed in response to a reduction in volumetric efficiency of the fuel pump. - View Dependent Claims (15, 16, 17, 18)
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Specification