Methods and systems are provided for a diagnostic routine of a variable displacement engine (VDE) of a vehicle to detect non-deactivated valves of deactivated cylinders due to a degraded valve deactivation mechanism. In one example, a method comprises, during operation of the VDE with one or more cylinders of the VDE deactivated, calculating a variation in a fast-sampled signal outputted by one or more exhaust gas oxygen (EGO) sensors of the VDE over a plurality of engine cycles; determining that the variation is greater than the threshold variation; and in response, indicating that valves of the one or more cylinders are not deactivated. A second method comprises estimating a throttle air flow rate and an engine air flow rate of the VDE; and indicating non-deactivated valves of one or more deactivated cylinders if the throttle air flow rate exceeds the engine air flow rate by a threshold.

In at least some implementations, a method of control-ling fuel injection events, includes determining at least one engine op-erating condition, determining timing of a desired pressure in an engine intake chamber or at the outlet of a fuel injector, and initiating a fuel injection event as a function of the at least one engine operating condition and the desired pressure. The fuel injection event is initiated prior to the desired pressure occurring and wherein the fuel injection event occurs for a duration such that the fuel injection event terminates after the desired pressure occurs.

An internal combustion engine control device includes an engine state estimation unit, a wall surface temperature estimation unit, and an operation amount calculation unit. The engine state estimation unit calculates the energy transfer amount from the gas to the wall surface based on the parameter related to the operating condition, the parameter related to the chemical condition of combustion, and the parameter related to an operation status. The wall surface temperature estimation unit estimates the wall surface temperature on the basis of the energy transfer amount from the gas to the wall surface. The operation amount calculation unit calculates an operation amount of an actuator provided in the internal combustion engine on the basis of the wall surface temperature estimated by the wall surface temperature estimation unit.

A method of operating an engine is provided. An exhaust valve actuation fault is detected for a first exhaust valve associated with a first cylinder during a first working cycle. In response to the detection of the exhaust valve actuation fault, fueling to at least the first cylinder is cut off. Actuation of the first exhaust valve is attempted in second working cycles that follow the first working cycle, wherein the second working cycles are not fueled. Whether or not the first exhaust valve actuated properly during the second working cycles is determined. Operation of the first cylinder is resumed when it is determined that the first exhaust valve actuated properly. Operation of the first cylinder is not resumed when it is determined that the first exhaust valve did not actuate properly.

A method for operating an internal combustion engine based on a control of a supplied fresh air quantity, the method comprising the following steps: implementing an adjustment of a throttle valve for the control of the supplied fresh air quantity as a function of a setpoint mass flow via the throttle valve; determining the setpoint mass flow via the throttle valve according to a differential equation, which is a function of a control deviation ascertained as a function of a setpoint intake manifold pressure and an actual intake manifold pressure.

A fuel injection timing is made later and/or a fuel injection amount is made larger in a target cylinder to be subjected to explosive combustion subsequently, when a required rotation time that is a time required for rotation of an output shaft by a predetermined rotational angle is equal to or longer than a time threshold than when the required rotation time is shorter than the time threshold, at the time of predetermined startup control in which an engine and a clutch are controlled such that fuel injection and ignition in the engine are resumed from a state where the supply of fuel to the engine is cut off and the clutch is released and that the clutch is then engaged.

A turbocharger system (1) of a combustion engine (4) comprises a turbocharger turbine (5) operable by exhaust gases, a valve (7) configured to control gas flow of pressurized gas from a pressurized gas reservoir (6) to the turbocharger turbine (5), and a sensor (8). Turbocharger system operation comprises injecting a test pulse of pressurized gas from the pressurized gas reservoir (6) to drive the turbocharger turbine (5) by means of controlling the valve (7), detecting an impact of injected pressurized gas on the turbocharger turbine (5) by means of the sensor (8), collecting data from the sensor (8), and diagnosing the turbocharger system (1) by evaluating an operational response of the turbocharger turbine (5) as a result of the injected test pulse of pressurized gas, based on the collected data.

The invention relates to a method for operating a fuel supply pump of a vehicle, the vehicle comprising a combustion engine system and a gearbox, the method comprising the steps of: determining one or more operational values of at least one operational parameter of the combustion engine system; determining a reduction of a fuel provision rate to the combustion engine system; determining whether a gear step change of the gearbox is at hand, on the basis of the determined one or more operational values of the at least one operational parameter; and in case a gear step change of the gearbox is at hand, controlling operation of the fuel supply pump so as to maintain fuel supply pump speed.

Methods and systems using model based and iterative calculations of mass flow throughout an internal combustion engine system. A secondary air injection valve is provided to selectively allow intake air to pass to the exhaust side of the engine system to aid in exothermic reaction with exhaust gasses exiting the engine for various purposes. The iterative calculations of mass flow include estimation of the mass flow through the secondary air injection valve.

A method for estimating pressure in an intake manifold of an indirect injection combustion engine. A pressure sensor measures pressure in the intake manifold, the intake manifold being in fluidic communication with a combustion cylinder, a piston guided in translation in the combustion cylinder and connected to a rotating crankshaft. The method includes: measuring, with the pressure sensor, a maximum pressure corresponding substantially to a maximum pressure in the intake manifold during a preceding cycle of the engine; measuring, with the pressure sensor, a minimum pressure corresponding substantially to a minimum pressure in the intake manifold during the preceding cycle of the engine; determining a pre-calculated average pressure correction factor from a crankshaft angular position and from an engine speed; and estimating the pressure in the intake manifold for the crankshaft angular position of the current engine cycle from the average correction factor and from the minimum and maximum pressures.