Methods and systems are provided for increasing a lift pump voltage to a high threshold voltage responsive to a DI pump efficiency being below a threshold efficiency, and increasing a lift pump voltage to a first threshold voltage less than the high threshold voltage responsive to a main jet pump fuel reservoir level being less than a first threshold reservoir level. The approach increases fuel jet pump performance and thereby reducing engine stalls induced by fuel vaporization, while maintaining DI pump efficiency and fuel economy.

A fuel system for a vehicle propulsion system includes a fuel temperature determination module that determines a temperature of a fuel, a fuel pressure determination module that determines a pressure of the fuel, a prime determination module that determines whether the determined fuel temperature is above a vaporization temperature on a predetermined distillation curve and the fuel pressure is below the predetermined distillation curve at the determined fuel temperature, and a controller programmed to command operation of a fuel pump in response to the prime determination module determining that the determined fuel temperature is above a vaporization temperature on the predetermined distillation curve and the fuel pressure is below the predetermined distillation curve at the determined fuel temperature.

A fuel return device couples to the high pressure side of a DI fuel system. The fuel return device provides for both continuous bleeding and occasional purging of fuel from the high pressure side to prevent issues related to vapor accumulation or heat-induced pressure increase. The fuel return device may be attached to a high pressure fuel rail in place of a sensor. The sensor may be attached the fuel return device. The fuel return device may include both an orifice that throttles the fuel flow through the fuel return device and a solenoid that allows the flow rate to be increased.

When a state where a lowered amount of a detection value of high-pressure side fuel pressure with respect to target fuel pressure is at least equal to a specified lowering determination value at least continues for a specified lowering determination time, a pump high-temperature determination is set ON. In the case where the pump high-temperature determination is set ON, boost control for increasing pressure of fuel that is supplied from a feed pump to a high-pressure pump (a set value of feed pressure) from a low-pressure set value to a high-pressure set value is executed.

Methods and systems are provided for diagnosing an in-range error of a pressure sensor arranged downstream of a lift pump in a fuel system of a vehicle. In one example, a method may include performing feedback control of the lift pump based on output of the pressure sensor, monitoring the pressure sensor output for flattening during the application of the voltage pulses, and adjusting operation of the fuel system depending on whether the pressure sensor output flattens for at least a threshold duration, which is indicative of an in-range error. The method may further include dynamically learning a setpoint pressure of a pressure relief valve of the fuel system and a fuel vapor pressure within the fuel system by monitoring pressure sensor output while adjusting the duty cycle of voltage pulses applied to the lift pump.

A fuel supply device includes a sub fuel tank disposed in a return fuel line, a pressure reduction valve, and a recirculation cutoff valve. When an internal combustion engine stops, the fuel supply device opens the pressure reduction valve and closes the recirculation cutoff valve. Due to this first transfer state, a liquefied gas fuel in a common rail is transferred to the sub fuel tank. Thereafter, the fuel supply device closes the pressure reduction valve and opens the recirculation cutoff valve. Due to this second transfer state, the liquefied gas fuel in the sub fuel tank is transferred to a main fuel tank. The fuel supply device repeatedly alternates between the first and second transfer states to collect the liquefied gas fuel from the common rail to the main fuel tank.

Methods and systems are provided for diagnosing an in-range error of a pressure sensor arranged downstream of a lift pump in a fuel system of a vehicle. In one example, a method may include performing feedback control of the lift pump based on output of the pressure sensor, monitoring the pressure sensor output for flattening during the application of the voltage pulses, and adjusting operation of the fuel system depending on whether the pressure sensor output flattens for at least a threshold duration, which is indicative of an in-range error. The method may further include dynamically learning a setpoint pressure of a pressure relief valve of the fuel system and a fuel vapor pressure within the fuel system by monitoring pressure sensor output while adjusting the duty cycle of voltage pulses applied to the lift pump.

Methods and systems are provided for diagnosing an in-range error of a pressure sensor arranged downstream of a lift pump in a fuel system of a vehicle. In one example, a method may include performing feedback control of the lift pump based on output of the pressure sensor, monitoring the pressure sensor output for flattening during the application of the voltage pulses, and adjusting operation of the fuel system depending on whether the pressure sensor output flattens for at least a threshold duration, which is indicative of an in-range error. The method may further include dynamically learning a setpoint pressure of a pressure relief valve of the fuel system and a fuel vapor pressure within the fuel system by monitoring pressure sensor output while adjusting the duty cycle of voltage pulses applied to the lift pump.

A water injection device of an internal combustion engine is provided. The water injection device includes a water tank for storing water, and a delivery element for delivering the water. The delivery element is connected to the water tank. The water injection device further includes at least one water injector for injecting water. The at least one water injector is connected to the delivery element. The water injection device further includes a pressure sensor, which is arranged in a line region between the delivery element and the water injector, and a control unit, which is designed to determine, on the basis of pressure data of the pressure sensor, a formation of vapour in the aforementioned line region when the water injector is closed and the delivery element is deactivated.

A low pressure fuel pump control system of a GDI engine may include a low pressure fuel pump primarily pressurizing fuel supplied from a fuel tank, a high pressure fuel pump secondarily pressurizing fuel from the low pressure fuel pump, a low pressure fuel pump pressure sensor and a high pressure fuel pump pressure sensor detecting fuel pressure of the low pressure fuel pump and the high pressure fuel pump, and a fuel supply pressure controller setting a final target pressure of the low pressure fuel pump by correcting a reference pressure, wherein the reference pressure is corrected by a low pressure correcting pressure according to temperature of the low pressure fuel pump and a correction pressure.