A method for operating a vehicle having a gasoline engine includes determining a density of a gasoline to be combusted in the gasoline engine, determining a stoichiometric air demand, determining a critical temperature from the density of the gasoline to be combusted and the stoichiometric air demand, and adapting countermeasures to prevent vapor bubbles based on the determined critical temperature.

Methods and systems are provided for estimating ethanol content in fuel, water content in fuel, and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content, water content, or fuel age based on fuel rail temperature, and two or more of a resonant frequency (f) of pressure pulsations, a change in fuel rail pressure (δp), and a damping coefficient (α) of pressure pulsations in the fuel rail as estimated after a fuel injection or a pump stroke. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content, water content, and fuel age.

A storage device is configured to store a first mapping that receives, as an input, a first input variable including a cam phase variable on present and past phases of a cam, and output a pulsating variable on a pulsating component. The execution device is configured to acquire the first input variable and estimate the pulsating variable by applying the acquired first input variable to the first mapping. Therefore, it is possible to estimate the pulsating variable without providing a low-pressure fuel pressure sensor by estimating a fuel pressure variable by applying the first input variable to the first mapping.

An estimation device is applicable to a combustion system including an internal combustion engine. The estimation device includes a mixing acquisition unit, a combustion amount estimation unit, and a region estimation unit. The mixing acquisition unit acquires the mixing ratio of various components contained in the fuel used for combustion in the internal combustion engine. The combustion amount estimation unit estimates a main combustion amount of the fuel caused by a main combustion produced by injecting the fuel into a combustion chamber of the internal combustion engine with a main injection, based on the mixing ratio acquired by the mixing acquisition unit. The region estimation unit estimates a combustion region of the main combustion in the combustion chamber based on the mixing ratio acquired by the mixing acquisition unit.

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.

Methods and systems are described for controlling fuel injection in an engine equipped with a dual injector system including a port injector and a direct injector. A ratio of port injected fuel to direct injected fuel is adjusted based at least on intake valve temperature. The proportion of fuel port injected into a cylinder is increased as the intake valve temperature for the given cylinder increases to improve fuel vaporization in the intake port.

Methods and systems are provided for estimating ethanol content in fuel and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content and/or fuel age based on fuel temperature, a speed of sound in fuel, and an attenuation co-efficient of an ultrasonic signal in fuel. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content and fuel age.

Methods and systems are provided for estimating ethanol content in fuel, water content in fuel, and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content, water content, or fuel age based on fuel rail temperature, and two or more of a resonant frequency (f) of pressure pulsations, a change in fuel rail pressure (p), and a damping coefficient () of pressure pulsations in the fuel rail as estimated after a fuel injection or a pump stroke. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content, water content, and fuel age.

Methods and systems are provided for estimating ethanol content in fuel, water content in fuel, and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content, water content, or fuel age based on a resonant frequency (f) of pressure pulsations, a change in fuel rail pressure (p), and a damping coefficient () of pressure pulsations in the fuel rail as estimated after a fuel injection or a pump stroke. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content, water content, and fuel age.

Systems and methods for controlling fuelling of dual fuel internal combustion engines are disclosed. The control techniques maximize the substitution rate of gaseous fuel for the liquid fuel by determining a target fuelling amount for the liquid fuel and then regulating an actual fuelling amount of the liquid fuel in response to engine speed and power variations and by modulating the flow rate of the gaseous fuel to the engine.