A method and apparatus to determine values for at least one fuel use characteristic variable which represents a first fuel use process in a first vehicle, are provided. In addition, values are determined for at least one parameter which represents at least one peripheral condition of the fuel use in the first vehicle during the first fuel supply process. A mathematical relationship is determined between one or more supplied values of the at least one fuel use characteristic variable and the corresponding values of the at least one parameter. A profile data record including a data record and/or learning data is supplied on the basis of at least one determined mathematical relationship. At least one further fuel parameter of a fuel which is used by the first vehicle and/or by a second vehicle during a second fuel use process is adapted as a function of the supplied profile data record.

A method for operating an engine system 200 comprising an engine 208 configured to consume a fuel, having at least a two flowmeters 214, 216, is provided. The method includes the step of operating an engine 208 disposed between a supply flowmeter 214 of the at least two flowmeters and a return flowmeter 216 of the at least two flowmeters. A first fuel density in the supply flowmeter 214 and a second fuel density in the return flowmeter 216 are measured. The fuel density measurements 317 between the supply flowmeter 214 and return flowmeter 216 are compared and a differential density measurement value, Δρ 319, based on a difference in the second fuel density and the first fuel density is determined. The Δρ 319 is compared to a range of theoretical differential fuel density values, Δρ.sub.t, and potential fuel contamination is indicated if the Δρ lies outside a range of Δρ.sub.t values by a predetermined threshold.

A method operates a fuel-supply system for an internal combustion engine. The fuel-supply system contains a high-pressure fuel pump, a high-pressure fluid accumulator having a fuel-injection valve, and a high-pressure sensor. A measurement signal of the sensor is representative of a pressure within the high-pressure fluid accumulator. The high-pressure fuel pump is fluidically connected on the outlet side to the high-pressure fluid accumulator. A respective maximum injection quantity of the fuel-injection valve is determined depending on the measurement signal of the high-pressure sensor. The injection quantity is determined depending on an efficiency characteristic representing the efficiency of the high-pressure fuel pump, the efficiency characteristic depending on the measurement signal of the high-pressure sensor. The at least one fuel-injection valve is actuated in such a way that a respective injection quantity to be metered by the at least one fuel-injection valve is limited to the respective maximum injection quantity.

A control device that controls an internal combustion engine includes an electronic control unit configured to, during an operation other than a start-up of the internal combustion engine, cause the fuel injection valve to execute one or a plurality of fuel injections in each cycle such that a target fuel injection amount in one injection becomes equal to or greater than a predetermined minimum injection amount, and when the internal combustion engine is started up, in a case where startability of the internal combustion engine is insufficient, execute an excess split injection control for causing the fuel injection valve to execute more fuel injections than the maximum number of fuel injections per cycle while making the target fuel injection amount in one injection smaller than the minimum injection amount per cycle and maintaining a target total fuel injection amount per cycle.

Systems, methods and apparatus for controlling operation of dual fuel engines are disclosed that regulate the fuelling amounts provided by a first fuel and a second fuel during operation of the engine. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The fuelling amounts are controlled to improve operational outcomes of the duel fuel engine.

A fuel separation system includes a fuel separator configured to receive a fuel stream and separate the fuel stream, based on a volatility of the fuel stream, into a vapor stream defined by a first auto-ignition characteristic value and a first liquid stream defined by a second auto-ignition characteristic value, the second auto-ignition characteristic value greater than the first auto-ignition characteristic value; and a control system communicably coupled to the fuel separator and operable to receive an input from an engine, the input including an engine operating condition, the control system configured to adjust an operating parameter of the fuel separator, based at least in part on the engine operating condition, to vary at least one of the first or second auto-ignition characteristic values.

Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

A control device of the present invention is applied to an engine provided with a fuel injection valve which directly injects fuel into a combustion chamber. The control device includes a pre-ignition prediction unit which predicts occurrence of pre-ignition when the engine is started; and an injection control unit which causes fuel to be injected in an expansion stroke from the fuel injection valve when occurrence of pre-ignition is predicted by the pre-ignition prediction unit. Thus, it is possible to prevent pre-ignition without lowering the effective compression ratio.

Systems and methods for controlling fuel factions delivered to different cylinders are provided. In one example, a controller is configured to, during a single engine cycle and responsive to a first condition, deliver a lower fraction of a first fuel into a donor cylinder in comparison to a fraction of the first fuel being injected into a non-donor cylinder and deliver a higher fraction of a second fuel into the donor cylinder in comparison to a fraction of the second fuel being injected into the non-donor cylinder.

Systems, methods and apparatus for controlling operation of an engine structured to combust gaseous fuel such as a dual fuel engine, including an estimation of key parameters dependent on natural gas quality, are disclosed. The natural gas quality parameters are estimated from natural gas properties obtained from various sensed parameters associated with the engine.