Methods and systems are disclosed for operating an engine that includes a knock control system. The method and system may increase opportunities to learn one or more engine knock background noise levels via changing poppet valve timing and/or fuel injection timing. The method and system may also improve knock detection if knock sensor degradation is suspected.

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

According to one or more embodiments, an internal combustion engine may be operated by a method which includes one or more of injecting a first fuel and a second fuel into an engine cylinder to form a fuel mixture, and combusting the fuel mixture with a spark plug to translate a piston housed in the engine cylinder and rotate a crank shaft coupled to the piston. The first fuel may comprise a greater octane rating than the second fuel. A target CA50 may correspond to a minimum in specific fuel consumption of the fuel mixture. The spark plug may initiate combustion at a time such that the internal combustion engine operates with an operational CA50 that is within 20 degrees of the target CA50.

Provided herein are processes and microorganisms which utilize both protein hydrolysates and carbohydrates from biomass feedstocks to produce renewable hydrocarbon compositions. Advantages of the disclosed methods may be recognized in fuel blends comprising such hydrocarbon compositions.

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.

An example method for operating an internal combustion engine may include: measuring pressure oscillations for a cylinder in the inlet tract at a defined operating point during normal operation; generating a corresponding oscillation signal; determining a crankshaft phase angle corresponding to the oscillation signal; and from the pressure oscillation signal, using discrete Fourier transformation to calculate the actual phase position of a selected signal frequency; determining a further comparison phase position in the same way from the selected signal frequency in the absence of fuel injection; calculating an actual phase position difference; on the basis of the difference, taking into consideration reference phase position differences of the same signal frequency for different fuel compositions, to identify a fuel composition of the presently used fuel; and adapting operating parameters of the engine based on the identified composition.

A blowback air amount is an amount of air that is part of the air that has flowed into a combustion chamber and is blown back into an intake passage before an intake valve closes. If the blowback air amount increases, a controller causes a fuel injection valve to inject fuel by an amount increased with respect to a fuel amount for a case in which the blowback air amount remains constant. The controller sets an increase amount of fuel injected from the fuel injection valve to a greater value when the stoichiometric air-fuel ratio of the fuel injected from the fuel injection valve is small than when the stoichiometric air-fuel ratio of the fuel injected from the fuel injection valve is great.

A method for operating an internal combustion engine may include: measuring dynamic pressure oscillations in the inlet tract at a defined operating point during normal operation; generating a corresponding pressure oscillation signal; determining a crankshaft phase angle; determining an actual phase position using the pressure oscillation signal by discrete Fourier transformation; determining a chemical composition of the fuel using the determined actual phase position and reference phase positions of the same signal frequency for different fuel compositions; and adjusting operating parameters of the internal combustion engine based on the determined chemical composition.

A control device is configured to, in a case that an internal combustion engine is made to start up before travel start of a vehicle in a parked state, when an auxiliary battery has at least a predetermined value of battery voltage, make the internal combustion engine start up after executing fuel heating processing for heating fuel by glow plugs to which electric power is transmitted, or when the battery voltage of the auxiliary battery is less than the predetermined value, execute the fuel heating processing after executing charge processing for charging the auxiliary battery using a main battery and then start up the internal combustion engine.

For controlling injection of a mixture fuel of ethanol and gasoline in an internal combustion engine, ethanol concentration of the mixture fuel supplied to the engine is detected, target operation information related to the engine is obtained, a division scheme of a plurality of injection regions is determined based on the ethanol concentration, an injection region corresponding to the target operation information is determined in the determined division scheme of injection regions corresponding to the ethanol concentration, and while performing injection of the mixture fuel corresponding to the determined injection region, at least one of injection timing and injection duration of the mixture fuel is varied according to the ethanol concentration.