An engine device including an engine capable of coping with both a premix combustion mode in which premixed fuel obtained by mixing fuel with air in advance is supplied into a cylinder and combusted and a diffusion combustion mode in which liquid fuel is injected into the cylinder and combusted. The engine device further includes a gas supply device configured to supply the gaseous fuel into the cylinder in the premix combustion mode; a pilot injection device configured to inject the liquid fuel into the cylinder in the premix combustion mode; and a main injection device configured to inject the liquid fuel into the cylinder in the diffusion combustion mode. The liquid fuel is injected from the main injection device and the liquid fuel is injected from the pilot injection device during the diffusion combustion mode, thus diagnosing failure in the pilot injection device.

Various methods and systems are provided for an engine capable of receiving liquid and gaseous fuel. In one example, cylinder misfire may be identified based on a misfire monitor. The misfire monitor may detect misfire based on signals from a crankshaft sensor.

A method for starting a gaseous fuel internal combustion engine is disclosed. According to the disclosed method, the engine is rotated using a start device until a first speed threshold is reached. After reaching the first speed threshold, pilot fuel is supplied to a plurality of cylinders of the engine to combust the same. After performing an ignition health check, gaseous fuel is supplied to all or a relatively large number of cylinders to start accelerating the engine up to a second speed threshold.

A combination control assembly for dual fuel internal combustion engine comprises: a bracket (8) that is fixed on an engine shell (12); a micro switch (9) that is used to send signals; a female quick connector (7) is used to connect with the carburetor and a male quick connector (10) is used to connect with the female quick connector (7); a gas pipe (11) is used to connect with the male quick connector (10) and the other side, gaseous fuel; the bracket (8) is provided with the micro switch (9) and the female quick connector (7), the micro switch (9) is provided with a reed (91), and the male quick connector (10) is provided with a trigger tab (101). When the male quick connector (10) is connected to the female quick connector (7), the trigger tab (101) is against the reed (91). A knob component (6) is connected with the fuel valve (5) to control fuel flow in the fuel pipe (4), and the engine flameout is also controlled by the knob component (6).

Various methods and systems are provided for an engine capable of receiving liquid and gaseous fuel. In one example, cylinder misfire may be identified based on a misfire monitor. The misfire monitor may detect misfire based on signals from a crankshaft sensor.

The present invention relates to a system for coping with a malfunction of an ethanol sensor of a FFV. The present invention provides a system for coping with a malfunction of an ethanol sensor of a FFV, the system including: a driving condition detector configured to determine whether a driving condition of the FFV is satisfied; an air-fuel ratio control condition detector configured to determine whether an air-fuel ratio control condition is satisfied; a timer unit configured to calculate a timer value by measuring time when an ethanol content value measured in the ethanol sensor is constant and when the driving condition and the air-fuel ratio control condition are satisfied; and a controller configured to synchronize an ethanol-content learned value with the ethanol content value measured in the ethanol sensor when it is determined that the timer value calculated in the timer unit is higher than a preset critical value.

A system for project planning for an engine for determining an operating behavior of the engine to be expected under defined operating conditions of the engine includes: a plurality of sensors configured to measure respective ones of the defined operating conditions of the engine; and a knocking intensity prediction tool configured to determine the knocking intensity of the engine to be expected under the defined operating conditions of the engine.

An engine device (21) including: an intake manifold (67) configured to supply air into a cylinder (77); an exhaust manifold (44) configured to output exhaust gas from the cylinder (77); a gas injector (98) which mixes a gaseous fuel with the air supplied from the intake manifold 67; and a main fuel injection valve (79) configured to inject a liquid fuel into the cylinder (77) for combustion. At the time of switching the operation mode from one to the other between a gas mode and a diesel mode, an instant switching to the diesel mode is executed when the engine rotation number is determined to approach the upper limit value which leads to an emergency stop of the engine device.

A dual-fuel conversion system that introduces natural gas into at least one engine cylinder and replaces diesel fuel with a replacement pilot fuel for ignition. The system includes replacement injectors that mount to an injector adapter that replaces the original diesel fuel injector, a control computer that is reprogrammed to control timing of the replacement injectors, and replacement fuel components to distribute natural gas and a pilot fuel to the at least one engine cylinder.

A method for deposit mitigation in a gaseous fuel injector that introduces a gaseous fuel through a gaseous fuel orifice directly into a combustion chamber of an internal combustion engine includes at least one of a) reducing the ago length of the gaseous fuel orifice by substantially between 10% to 50% of a previous length of a previous gaseous fuel orifice showing deposit accumulation above a predetermined threshold; b) providing the gaseous fuel orifice with an inwardly and substantially linearly tapering profile; c) determining deposit mitigation is needed; and performing at least one of the following deposit mitigation techniques i) increasing gaseous fuel injection pressure wherein deposit accumulation is reduced during fuel injection; and ii) decreasing gaseous fuel temperature wherein a rate of deposit accumulation is reduced; and d) injecting compressed air through the gaseous fuel orifice during shutdown of the internal combustion engine; whereby torque loss in the internal combustion engine due to deposit accumulation in the gaseous fuel orifice is reduced below a predetermined value.