A dual fuel system includes a liquid pilot fuel supply, a liquid main fuel supply, and a fuel injection apparatus. The dual fuel system further includes a fueling control unit coupled with a cylinder pressure sensor and a NOx sensor, and structured to vary, via outputting a fueling control command to a main fuel injection control valve, fuel delivery parameters each on the basis of at least one of a cylinder pressure parameter or a NOx parameter. The fueling control unit compensates via the varying fuel delivery parameters for a change to a liquid main fuel composition such as a change from a first alcohol fuel or blend to a second alcohol fuel or blend.

Emission targets, such as NOx levels, for gaseous fuelled internal combustion engines that burn a gaseous fuel in a diffusion combustion mode are increasingly more challenging to achieve. A method of fuel injection for an internal combustion engine fuelled with a gaseous fuel comprises introducing a first amount of pilot fuel in a first stage of fuel injection; introducing a first amount of main fuel (the gaseous fuel) in a second stage of fuel injection; and introducing a second amount of main fuel in a third stage of fuel injection. The first and second amounts of main fuel contribute to load and speed demand of the internal combustion engine. Engine maps calibrated for different engine performance can be employed in different regions of the load and speed range of the engine. The engine maps are blended when the engine transitions between two regions; and momentary excursions into different regions do not change the engine calibration.

An improved body defining a restricted fluid flow passage in a fuel supply system for delivering a gaseous fuel to an internal combustion engine. The body is formed for installation between and fluidly connecting a gaseous fuel supply conduit and a gaseous fuel flow passage that defines a predetermined volume between the restricted fluid flow passage and a nozzle chamber of a fuel injector from which the gaseous fuel is injected into the internal combustion engine. The restricted fluid flow passage has the smallest effective flow area between the gaseous fuel supply conduit and the nozzle chamber. The restricted fluid flow passage is located a predetermined distance from an injection valve seal within the fuel injector. The predetermined distance is calculated as a function of the speed of sound in the gaseous fuel and an opened time of the fuel injector.

Methods and systems are provided for a multi-fuel engine. In one example, a method includes adjusting a substitution ratio based on an intake manifold temperature. The method further including adjusting the intake manifold temperature to increase the substitution ratio.

Methods and systems are provided for adjusting a location of a fuel injection in response to a substitution rate and a desired EGR flow. In one example, a method may include injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber, injecting a second, different, fuel to the combustion chamber via an exhaust port injector positioned to inject toward an exhaust valve of the combustion chamber, and combusting the first and second fuels together in the combustion chamber.

The present invention discloses a method of introducing fuel into a diesel engine for combustion within the engine. A natural gas in liquid form is injected into the engine for combustion therein with diesel fuel so as to maintain a natural gas concentration derived from the liquid in the range of greater than 0.6% to 3.0% of air intake by volume of natural gas. Suitable gases include natural gas, methane or substantially methane gas mixtures and substitute natural gas such as propane air mixtures providing a mixture with similar combustion properties to methane/natural gas.

Various methods and systems are provided for using only hydrogen as fuel in a duel fuel engine. In one example, a method may include direct injecting only hydrogen as fuel to one or more engine cylinders and compression igniting the injected hydrogen.

An apparatus for controlling a gasoline-diesel complex combustion engine includes an engine generating driving torque by burning gasoline fuel and diesel fuel, a driving information detector for detecting driving information of the engine, and a controller for controlling a diesel injector such that diesel fuel is injected as a single injection or a split injection based on a driving region and a knock intensity included within the driving information.

Methods and systems are provided for improving engine knock control by accounting for a drop in charge cooling efficiency of a knock control fluid at higher temperatures. In response to the prediction of an elevated temperature of a knock control fluid at a time of release from a direct injector, a pulse width of the injection is adjusted. Any knock relief deficits are compensated for using alternate engine adjustments, such as boost or spark timing adjustments.

A fuel valve includes a housing, a nozzle with nozzle holes opening to a volume inside the nozzle at the front end of the housing, a gaseous fuel inlet port in the housing connected to high pressure gaseous fuel, an axially displaceable valve needle received in a longitudinal bore in the housing, and rests on a valve seat in a closed position and has lift from the valve seat in an open position, the valve seat placed between a fuel chamber and an outlet port, the fuel chamber connected to the fuel inlet port, the outlet port connected to the volume in the nozzle, an actuator system for moving the needle between the closed and open positions, an ignition liquid inlet port connected to high pressure ignition liquid, and conduit connecting the ignition liquid inlet port to the fuel chamber, the conduit including a fixed flow restriction.