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.

Various methods and systems are provided for skipping fire in one or more cylinders in a dual fuel engine. In one example, a method may include injecting a combination of two fuels to a first set of cylinders of the engine while disabling fuel injection to all remaining cylinders of the engine.

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.

An apparatus and method for igniting a gaseous fuel directly introduced into a combustion chamber of an internal combustion engine comprises steps of heating a space near a fuel injector nozzle; introducing a pilot amount of the gaseous fuel in the combustion chamber during a first stage injection event; controlling residency of the pilot amount in the space such that a temperature of the pilot amount increases to an auto-ignition temperature of the gaseous fuel whereby ignition occurs; introducing a main amount of the gaseous fuel during a second stage injection event after the first stage injection event; and using heat from combustion of the pilot amount to ignite the main amount.

A secondary fuel injection system determines (precisely) a maximum amount of secondary fuel that can be injected into a cylinder during a cycle based upon the rotational speed (RPM) of the engine. A primary fuel injection pulse width of the prior cycle and is used to determine how much heat energy was requested by an engine control module based upon the duration of the injection pulse. Secondary fuel is injected into the intake port of the cylinder after the exhaust valve closes in an amount that is calculated based upon the maximum that can be injected during the allowed calculated time of crankshaft rotation and the amount of heat energy requested in the prior cycle and to include the amount of primary fuel that is then injected into the cylinder is being reduced based upon the amount of heat energy provided by the secondary fuel that was previously injected.

A method of reducing carbonaceous deposits on a fuel injector is provided in which a first fuel composition is supplied to the fuel injector in a dual fuel engine, the first fuel composition comprising natural gas fuel and a first percentage of diesel fuel; and a second fuel composition is supplied to the fuel injector in a dual fuel engine, the second fuel composition comprising a second percentage of diesel fuel that is greater than the first percentage of diesel fuel to cause cavitation to occur within the fuel injector, thereby reducing carbonaceous deposits.

An engine including a main fuel injection valve, a pilot fuel injection valve, a liquid fuel supply rail pipe, and a pilot fuel supply rail pipe. The main fuel injection valve supplies liquid fuel from the liquid fuel supply rail pipe to a combustion chamber during combustion in a diffusion combustion system. The pilot fuel injection valve supplies pilot fuel from the pilot fuel supply rail pipe to the combustion chamber in order to ignite gaseous fuel during combustion in a premixed combustion system. The liquid fuel supply rail pipe is disposed at one side of an imaginary vertical plane (P1) including an axis of a crank shaft. The pilot fuel supply rail pipe is disposed at the side of the imaginary vertical plane at which the liquid fuel supply rail pipe is disposed.

Methods and systems are provided for integrating a bi-fuel engine with a CVT transmission. Responsive to a driver demand, a controller may determine whether to maintain usage of a current fuel or transition to an alternate fuel based on the cost efficiency of the transition and further based on any engine limitations that may be incurred at the engine speed-load following the transition. To improve the net fuel economy benefit while addressing the engine limitation, a fuel transition may be combined with a CVT adjusted engine speed-load regime, while maintaining engine power output.

An objective of the present invention is to stabilize the fuel injection amount for each cylinder and to execute fuel injection control accurately in a single-pressure-feed dual-injection type alcohol fuel injection system. An engine includes two injection valves and and a single-pressure-feed dual-injection type fuel supply system. The fuel supply system is configured such that fuel is injected sequentially in two cylinders during the pressure-feed-interval period from the execution of one fuel pressure-feed operation to the execution of the next fuel pressure-feed operation. If the alcohol concentration in the fuel is higher than a predetermined determination value γ at a startup operation time, an ECU executes only a cylinder injection for the first of the two cylinders described above, and executes both an intake passage injection and a cylinder injection for the second cylinder. Thus, even if the fuel pressure decreases due to the fuel injection for the first cylinder, the required fuel injection amount can be reserved for the second cylinder.