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.

Various embodiments include a method for diagnosis of a high-pressure sensor of a motor vehicle comprising: measuring a pressure with the high-pressure sensor; feeding the measured pressure to a control unit; evaluating the measured pressure with the control unit and determining a control signal for an amount of fuel to be injected; checking whether a first difference between two successive values of the pressure measurement signal is greater than a calculated maximum difference value; checking whether a second difference between a minimum pressure measurement signal measured within a time segment and a maximum pressure measurement signal measured within the time segment is less than an expected change in the pressure measurement signal; and checking whether a measured pressure gradient is smaller than an expected pressure gradient.

A method and a system for determining a temperature for pressurized fuel included in a high pressure fuel system arranged for providing fuel to an engine are presented. The method includes determining a first temperature for a first fuel volume included in a first section of the high pressure fuel system, where the first section includes a common rail fuel system. The method further includes determining a second temperature for a second fuel volume included in a second section of the high pressure fuel system, where the second section includes at least one fuel injector arranged in a cylinder head of the engine. The method also includes the step of determining the temperature for the pressurized fuel based at least on the first temperature and on the second temperature.

A device for discharging fuel vapor from a fuel supply system for an internal combustion engine has a container which is situated in the fuel supply system and contains liquid fuel under an upwardly limited pressure. A discharge line, which leads to a tank venting system, leads out of the container. The device also has a detector for detecting vaporous fuel in the container and a blocking device which is coupled to the detector and with which the discharge line can be opened or blocked depending on the detection. A method for discharging fuel vapor from a fuel supply system for an internal combustion engine continuously detects whether vaporous fuel is also present in the container which is situated in the fuel supply system and contains the liquid fuel under an upwardly limited pressure; opens the discharge line if the vaporous fuel has been detected and blocks the discharge line if no vaporous fuel has been detected; and discharges the vaporous fuel through the opened discharge line while retaining the liquid fuel.

A method to control the combustion of a compression ignition engine having the steps of: establishing, for each combustion cycle, a fuel quantity to be injected into the cylinder; injecting a first fraction of the fuel quantity; heating a second fraction of the fuel quantity, which is equal to the remaining fraction of the fuel quantity, to an injection temperature higher than 100° C.; injecting the second fraction of the fuel quantity heated to the injection temperature into the cylinder at the end of the compression stroke and at no more than 60° from the top dead centre; and decreasing the injection temperature and the ratio between the second fraction and the first fraction as the internal combustion engine increases and as the rotation speed of the internal combustion engine increases.

An objective of the disclosure is to provide a method for calculating a one-dimensional (1D) spatial fluctuation in an unbranched high-pressure fuel pipe of a common rail system. The method includes the following steps: dividing a flow in the unbranched high-pressure fuel pipe according to a spatial length into sections for solving, to obtain forward and reverse pressure fluctuation forms; iteratively calculating forward and reverse pressure fluctuations propagating in a fuel pipe model to obtain fluctuations of various sections of the fuel pipe from an inlet to an outlet within one step, and calculating a flow velocity at a corresponding position in the pipe; and extracting a corresponding flow rate of the system, and substituting into an iterative calculation of the overall system to obtain an output pressure.

The invention provides a vehicle engine system comprising: a fuel pump for selectively delivering fuel under high pressure; an accumulator having a first chamber for receiving an output from the fuel pump and a second chamber for receiving an oil feed, wherein as one chamber is filled up the other chamber is compressed; wherein on vehicle acceleration the fuel pump delivers fuel to a common rail fuel injection system, and on vehicle braking the fuel pump delivers fuel to the first chamber of the accumulator to thereby put the oil in the second chamber under pressure, and wherein on subsequent acceleration the oil chamber delivers an output under pressure.

Methods and systems are provided for relieving pressure from a compression locked engine. The engine may be compression locked during an engine start attempt due to operator application of a manual transmission clutch at or around the time of a first combustion event of the engine start. A direct injector of the compression locked cylinder is commanded open to relieve the pressure into the fuel rail.

A method for operating an internal combustion engine, including aligning an injection behavior of the number of injectors. Aligning the injection behavior includes switching off one injector of the number of injectors, detecting a signal of the internal combustion engine that is to be assigned to the switched off injector, determining an alignment characteristic from the signal and assigning the alignment characteristic to the switched off injector as an alignment characteristic assigned to the injector, and switching on the previously switched off injector. Aligning the injection behavior further includes performing the aforementioned steps sequentially for the other injectors of the number of injectors and correcting a control of an injector that is to be corrected using the measured value assigned to the injector that is to be corrected.

A pump life prediction system and methods for predicting pump life of a pump are disclosed. A method may include monitoring pump operating conditions. A value indicative of cavitation damage is determined based on the pump operating conditions. A pump life remaining is determined based on the value. The method may also include outputting an indication of the pump life remaining.