A vehicle propulsion system includes a first pump having an inlet for receiving fuel from a fuel reservoir and an outlet for providing pressurized fuel to a fuel feed line at a first pressure, a fuel feed line pressure sensor, a second pump having an inlet for receiving fuel from the fuel feed line and an outlet for providing pressurized fuel to an engine fuel rail at a second pressure, the second pressure being higher than the first pressure, a fuel temperature sensor, and a controller controlling the first pump to reduce the pressure of the fuel in the fuel feed line and determining whether the pressure of the fuel in the fuel feed line has reached a vaporization pressure of a component in the fuel.

Methods and systems are provided for tracking a fuel puddle mass in the intake port of a deactivated engine cylinder. The difference in fuel evaporation rate in the deactivated cylinder intake is accounted for by applying distinct time constant and gain values to a transient fuel compensation model. A fuel vapor content is clipped once the intake vapor pressure in the intake port of the deactivated cylinder reaches a saturation pressure limit.

Methods and systems are provided for improved injector balancing. In one example, fuel rail pressure samples collected during a noisy zone of injector operation are discarded while samples collected during a quiet zone are averaged to determine an injector pressure. The injector pressure is then used to infer injection volume, injector error, and update an injector transfer function.

Methods and systems are provided for refilling a fuel tank devoid of fuel vapors. In one example, a method may include, prior to an upcoming refueling event, conditioning a fuel vapor-less fuel tank by operating a fuel pump. Operation of the fuel pump may agitate and vaporize the residual fuel in the fuel tank.

A delivery device for delivering a medium in a vehicle and for limiting a system pressure of the delivery device includes a vehicle pump, which is driven by an electric motor. The electric motor is controlled by a controller, the controller being configured to detect an actual rotational speed of the electric motor and an actual operating current of the electric motor. If the actual operating current of the electric motor exceeds a predefined operating current limit value, the controller is configured to generate a first signal relating to a system pressure being exceeded. The predefined operating current limit value is dependent on the actual rotational speed of the electric motor.

Described herein is a process for designing a virtual sensor that is able to estimate a variable of interest v as a function of a set of available variables u.sub.i. The process comprises the steps of: acquiring (1002) a design data-set D.sub.d comprising a number N of measured values v(ti) of the variable of interest v and corresponding measured values i(ti) of the available variables u.sub.i; determining a limit on the disturbances of the available variables u.sub.i and a limit on the errors of the method of measurement of the variable of interest v; selecting (1004) a Lipschitz function * with a respective Lipschitz constant , which is able to estimate the variable of interest v(t) as a function of a number n of past values of each available variable u.sub.i, by executing the following steps one or more times for different numbers n: a) determining a value for the Lipschitz constant y; b) defining (1006) a maximum limit (r(t)) and a minimum limit (r(t)) for the estimate of the variable of interest v as a function of the design data-set D.sub.d, and moreover the number n, the value for the Lipschitz constant y, the limit on the disturbances of the available variables u.sub.i, and the limit on the errors of the method of measurement of the variable of interest v, and choosing a Lipschitz function * comprised between the maximum limit (r(t)) and the minimum limit (r(t)); c) determining (1008) an estimation error *(*) for the Lipschitz function * and selecting the Lipschitz function *, associated to which is a respective Lipschitz constant y* and a respective number n*, that presents the minimum estimation error *(*(y*, n*)); and implementing (1012) the selected Lipschitz function * in an electronic circuit.

Methods and systems are provided for an integrated fuel composition-pressure sensor. In one example, the integrated sensor may include a set of cylindrical capacitors and a set of plate capacitors with a common capacitor element shared between the sets. A composition of fuel may be determined from the set of cylindrical capacitors and a pressure of fuel may be determined from the set of plate capacitors.

Systems and methods are provided for operating a port fuel and direct injection fuel system of a rolling variable displacement engine (rVDE). In one example, a method may include selecting between controlling a lift pump of the fuel system to output fuel at a mechanically limited pressure and controlling the lift pump to output fuel at a pressure lower than the mechanically limited pressure based on whether port fuel injection is used. In this way, the lift pump may be controlled without feedback from a pressure sensor, reducing system costs, while electrical power consumption increases due to operating the lift pump to output fuel at the mechanically limited pressure are minimized due to the rVDE technology, which reduces port fuel injection usage.

A fuel injection control device includes processing circuitry, which executes an estimating process to estimate pressure in first and second fuel storage members connected to first and second fuel injection valves. The estimating process includes: estimating the pressure in the first fuel storage member based on a detection value of a pressure sensor that detects the pressure in the first fuel storage member and a cycle of pulsation in the first fuel storage member, which is determined in accordance with an interval of fuel injections in a first bank; and estimating the pressure in the second fuel storage member by assuming that a phase of a periodic fluctuation of the pressure in the second fuel storage member and a phase of a periodic fluctuation of the pressure in the first fuel storage member are in antiphase.

A vehicle propulsion system includes a first pump having an inlet for receiving fuel from a fuel reservoir and an outlet for providing pressurized fuel to a fuel feed line at a first pressure, a fuel feed line pressure sensor, a second pump having an inlet for receiving fuel from the fuel feed line and an outlet for providing pressurized fuel to an engine fuel rail at a second pressure, the second pressure being higher than the first pressure, a fuel temperature sensor, and a controller controlling the first pump to reduce the pressure of the fuel in the fuel feed line and determining whether the pressure of the fuel in the fuel feed line has reached a vaporization pressure of a component in the fuel.