Methods and systems for accurate and precise fuel supply control for continuous-flow of gaseous fuel to an internal combustion engine over a large dynamic power range, including a dual-stage valve that allows optimal controla first stage in the form of a voice-coil driven electronic pressure regulator, and a second stage in the form of a voice-coil-driven choked-flow valve; monitoring the pressure of the fuel intermediate the two stages and making appropriate adjustments to the first stage via a pressure actuator loop; feeding the gaseous fuel mixture through a unitary block assembly into the second stage; monitoring the pressure of the air/fuel mixture and making appropriate adjustments to the second stage via a valve actuator control loop.

A controller for a gas engine includes a cycle detection unit 67 configured to detect a crank angle period of a single combustion cycle of an engine including a plurality of cylinders based on a crank angle detection value inputted from a crank angle detector 75, a misfire detection unit 69 configured to detect a misfire in a combustion chamber 37 based on an in-cylinder pressure detection value inputted from the in-cylinder pressure detector 59, and a simultaneous misfire determination unit 73 configured to determine a simultaneous misfire of more than one cylinder when a total number of cylinders where the misfire is detected in the single combustion cycle by the misfire detection unit 69 is not less than a preset threshold value of a cylinder number. The fuel gas to all of the cylinders is shut off when the simultaneous misfire of more than one cylinder in the single combustion cycle is determined by the simultaneous misfire determination unit 73.

A control device of a spark-ignition engine is provided. The control device includes a main body of the engine, a fuel injection valve, an ignition plug, and a controller. According to an engine operating state, the controller switches between a compression-ignition mode in which compression-ignition combustion is performed, and a spark-ignition mode in which spark-ignition combustion is performed. The controller switches from the spark-ignition mode to the compression-ignition mode by performing in order, a first stage where an air-fuel ratio of mixture gas is set to a predetermined value and the spark-ignition combustion is performed, a second stage where the air-fuel ratio of the mixture gas is set leaner than the first stage and the compression-ignition combustion is performed, and a third stage where the air-fuel ratio of the mixture gas is set richer than the second stage and the compression-ignition combustion is performed.

Methods and systems are provided for estimating an engine exhaust pressure based on outputs from an exhaust oxygen sensor. In one example, a method may include estimating an exhaust pressure of exhaust gas flowing through an engine exhaust passage based on a difference between a first output of an oxygen sensor disposed in the exhaust passage and a second output of the oxygen sensor and then adjusting engine operation based on the estimated exhaust pressure. As one example, both the first and second outputs may be taken while operating the sensor in a variable voltage mode, after increasing a reference voltage of the oxygen sensor from a lower, first voltage to a higher, second voltage.

Multiple mode control system for a vehicle includes a vehicle control unit operatively configured with manual override switch, one or plurality of sensors, audio output means and electronic control unit (ECU). The vehicle control unit includes processor configured with Read Only Memory, random access memory, analog to digital converter, switch driver and an optional communication engine and hard disk drive. The engine of the vehicle is configured with electronic control unit.

Systems and methods for determining normalized fuel-air ratio error for a cylinder of an engine an engine are disclosed. In one example, the engine is operated in a four-cylinder mode to generate a first normalized fuel-air ratio error for a first cylinder and operated in an eight-cylinder mode to generate a second normalized fuel-air ratio error for a second cylinder.