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.

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 control device for an engine includes an electronic control unit configured to estimate a water content mixed in engine oil based on a history of a fuel injection amount during an operation of the engine and restrain freezing of water such that, when the water content thus estimated is a predetermined amount or more, the electronic control unit increases a mixing amount of the fuel into the engine oil as compared with a case where the water content thus estimated is less than the predetermined amount. The control device estimates the water content mixed in the engine oil as a function of an integrated value of water content while an oil temperature of the engine is less than a predetermined temperature.

A method for determining the composition of a fuel in a lubricant in an internal combustion engine in disclosed. The composition of a fuel having at least a first portion of a first fuel component and a second portion of a second fuel component is predefined. The mass flow with which the fuel is introduced into the lubricant in an introduction phase or discharged from the lubricant and from the housing in a discharge phase is determined. The composition of the mass flow is determined from a first mass flow of the first fuel component and a second mass flow of the second fuel component, which are determined based on a) an introduction parameter in the introduction phase or a discharge parameter in the discharge phase, and b) the first portion of the first fuel component and the second portion of the second fuel component in the fuel.

An internal combustion engine to which the apparatus is applied is a multi-cylinder internal combustion engine that includes a passage injection valve and a cylinder injection valve and that can use gasoline and alcohol as fuel. The apparatus performs abnormality determination for a determination object device, based on a detection signal of an oxygen sensor provided in an exhaust passage of the internal combustion engine. The concentration sensor detects alcohol concentration ALp of the fuel in a first fuel passage through which the fuel is fed to the passage injection valve, and alcohol concentration ALd of the fuel in a second fuel passage through which the fuel is fed to the cylinder injection valve. When a difference AL between the alcohol concentrations ALp, ALd is a determination value or greater (S13: YES), the execution of the abnormality determination is prohibited (S12).

A controller (an engine controller 100) feeds a fuel into a cylinder 11 through a fuel feeder (including a fuel injection valve 53 and a fuel feeding system 54) when the cylinder 11 is in an intake stroke and a compression stroke and if an engine body (an engine 1) is both in a cold running phase and under a heavy load. The engine body at or below a predetermined temperature is in the cold running phase. The load applied to the engine body is heavy when the engine body is under at least a predetermined load. The controller also lowers the upper limit of the charging efficiency of the engine body as the vaporization rate of the fuel fed into the cylinder decreases.

Methods and systems are provided for estimating an amount of exhaust gas recirculation (EGR) from an exhaust passage into an intake passage of an engine system by operating an exhaust oxygen sensor in a variable voltage (VVs) mode. In one example, a method includes during operation of an exhaust oxygen sensor in the VVs mode where a reference voltage of the exhaust oxygen sensor is adjusted from a lower, first voltage to a higher, second voltage, adjusting engine operation based on the EGR amount estimated based on an output of the exhaust oxygen sensor and a learned correction factor based on the second voltage. In this way, the exhaust oxygen sensor may be used to correct for variations arising due to changing fuel composition and ambient humidity and further used to estimate the amount of EGR being recirculated in the system, thereby enhancing engine fueling and EGR control.

A method is provided for determining fuel blend in a dual fuel mixture including a first and a second fuel in an internal combustion engine. The method includes the steps of measuring multiple engine parameters using sensors during transient cycle operation for a predetermined range of engine loads and fuel blends; using system identification of transient time series of the measurements to determine one or more relevant engine parameters; determining a model for estimation of the fuel blend based on said one or more engine parameters; using the model for determining a current fuel blend during transient operation using current measured values of the one or more engine parameters, and using the calculated current fuel blend for controlling the amount of dual fuel mixture injected into each cylinder of the internal combustion engine. A vehicle and a computer program product using the method are also provided.

A system of one or more computers configured to perform operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that causes the system to perform the actions. The programs can be configured to perform operations, when executed by computer, cause the computer to perform the actions. One general aspect includes a system, a program to initiate an evaporative control engine off natural vacuum test in a vehicle and identify a geolocation where a fuel was obtained for the vehicle. The system then determines an e100 value and an e0 value for a temperature of the fuel and determines a vehicle percentage of ethanol of the fuel using at least the e100 value, the e0 value, a timestamp, and a fuel tank pressure and adjusts at least one engine parameter based upon the percentage of ethanol of the first fuel.

A system of one or more computers configured to perform operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that causes the system to perform the actions. The programs can be configured to perform operations, when executed by computer, cause the computer to perform the actions. One general aspect includes a system, a program to initiate an evaporative control engine off natural vacuum test in a vehicle and identify a geolocation where a fuel was obtained for the vehicle. The system then determines an e100 value and an e0 value for a temperature of the fuel and determines a vehicle percentage of ethanol of the fuel using at least the e100 value, the e0 value, a timestamp, and a fuel tank pressure and adjusts at least one engine parameter based upon the percentage of ethanol of the first fuel.