Methods and systems are provided for injector balancing without disabling a cam actuated high pressure fuel pump. In one example, one of a plurality of cam lobes of the pump is selectively and sequentially disabled while a group of injectors are concurrently operated to learn a pressure drop across each injector. The selection of the injectors is based on the identity and stroke timing of the disabled cam lobe.

Methods and systems are provided for reducing errors in estimated fuel rail pressure incurred at the time of a scheduled injection event due to engine-driven cyclic fuel rail pressure changes. In one example, a pulse-width commanded during a scheduled injection event is determined as a function fuel rail pressure samples collected over a moving window that is customized for the corresponding fuel injector. In another example, the commanded pulse-width is determined as a function of an average fuel rail pressure sampled during a quiet zone of injector operation and predicted fuel rail pressure altering events occurring between the quiet zone and the scheduled injection event.

Methods and systems are provided for reducing errors in estimated fuel rail pressure incurred at the time of a scheduled injection event due to engine-driven cyclic fuel rail pressure changes. In one example, a pulse-width commanded during a scheduled injection event is determined as a function fuel rail pressure samples collected over a moving window that is customized for the corresponding fuel injector. In another example, the commanded pulse-width is determined as a function of an average fuel rail pressure sampled during a quiet zone of injector operation and predicted fuel rail pressure altering events occurring between the quiet zone and the scheduled injection event.

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.

The invention provides a device and a method for determining a pressure of a fuel (19) which is to be injected into a combustion chamber (23) via a controllable closure element (11) of a solenoid valve (1), wherein the method comprises: generating a current flow (i) through a coil (3) of the solenoid valve (1) in order to generate a magnetic field, in order to generate a magnetic force acting on an armature (9), which magnetic force shifts the armature (9) in the direction of the opening of the closure element (11), determining a magnitude of a magnetic flux () of the magnetic field before or when a first state (I) at which the armature starts to shift the closure element is reached, and determining a magnitude of the pressure on the basis of the determined magnitude of the magnetic flux.

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 diagnosing an exhaust waste-gate valve via an electric boost assist motor of an electric turbocharger. Degradation of the waste-gate valve is inferred based on the motor torque profile of the motor after commanding the waste-gate valve to an open or closed position on a torque transient. Deviation of the motor torque profile from the expected profile is used to infer if the valve is stuck open or closed, and actions are taken accordingly.

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.

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 method for ascertaining a viscosity of a fuel with the aid of an electric fuel pump which is integrated into a fuel circuit including an overflow valve which includes a permanently open discharge channel, a fuel supply and delivery being adjusted with the aid of the electric fuel pump in the fuel circuit at a specific pressure and the viscosity of the fuel being ascertained by taking into account a delivery rate of the electric fuel pump.