Abstract: Methods and systems for operating an engine that includes two fuel pumps are described. In one example, a first fuel pump may be activated or remain activated in response to an engine shutdown request so that a second fuel pump may be cooled before the first fuel pump is deactivated in response to the engine shutdown request.

Abstract: A fuel line check valve system and a fuel system that includes the fuel line diaphragm valve system are described. The fuel line diaphragm valve system may prevent flow into a fuel system that is generated via a vacuum in the fuel system. The fuel line diaphragm valve may also remain in an open state after it is open via a reduced pressure.

Abstract: A fuel line check valve system and a fuel system that includes the fuel line diaphragm valve system are described. The fuel line diaphragm valve system may prevent flow into a fuel system that is generated via a vacuum in the fuel system. The fuel line diaphragm valve may also remain in an open state after it is open via a reduced pressure.

Abstract: Methods and systems are provided for characterizing aged fuel, which loses volatility over time. In one example, a method may include estimating a fuel vapor pressure during an engine cold start using a pre-determined fuel distillation curve and adjusting one or more combustion parameters based on the estimated fuel vapor pressure. Because the fuel vapor pressure directly relates to the fuel volatility, adjusting the one or more combustion parameters based on the estimated fuel vapor pressure may reduce aged fuel-related engine performance degradation, such as hesitation and emissions during cold start.

Abstract: Methods and systems are provided for characterizing aged fuel, which loses volatility over time. In one example, a method may include estimating a fuel vapor pressure during an engine cold start using a pre-determined fuel distillation curve and adjusting one or more combustion parameters based on the estimated fuel vapor pressure. Because the fuel vapor pressure directly relates to the fuel volatility, adjusting the one or more combustion parameters based on the estimated fuel vapor pressure may reduce aged fuel-related engine performance degradation, such as hesitation and emissions during cold start.

Abstract: Systems and methods are provided for a high-pressure fuel pump to mitigate audible ticking noise associated with opening and closing of a digital inlet valve of the high-pressure pump. To reduce the ticking noise associated with the high-pressure pump when the engine is idling, a solution is needed that is simple and does not involve retrofitting the fuel system with noise, vibration, and harshness countermeasures to mask the noise. Pressure devices and associated operation methods are provided that involve adding a combination of several check valves, an accumulator, and a flow control valve with weep channels to allow the digital inlet valve to be deactivated during engine idling as defined by a threshold engine speed.

Abstract: Systems and methods are provided for a high-pressure fuel pump to mitigate audible ticking noise associated with opening and closing of a digital inlet valve of the high-pressure pump. To reduce the ticking noise associated with the high-pressure pump when the engine is idling, a solution is needed that is simple and does not involve retrofitting the fuel system with noise, vibration, and harshness countermeasures to mask the noise. Pressure devices and associated operation methods are provided that involve adding a combination of several check valves, an accumulator, and a flow control valve with weep channels to allow the digital inlet valve to be deactivated during engine idling as defined by a threshold engine speed.