An engine device including: an intake manifold configured to supply air into a cylinder; an exhaust manifold configured to output exhaust gas from the cylinder; a gas injector which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve configured to inject a liquid fuel into the cylinder 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 vehicular propulsion system, a vehicular fuel system and a method of operating an internal combustion engine. A separation unit that makes up a part of the fuel system includes one or more adsorbent-based chambers such that the separation unit may selectively receive and separate at least a portion of onboard fuel into octane-enhanced and cetane-enhanced fuel components. A supply tank includes three compartments where the first contains the onboard fuel, the second receives a vaporized adsorbate from the separation unit and condenses at least a part of it into one of an octane-rich fuel component or a cetane-rich fuel component, while the third may either store the condensed and enriched fuel component or help condense more of the vaporized adsorbate. The condensing takes place through heat exchange between the onboard fuel and the vaporized adsorbate that are present within the various compartments of the supply tank. A controller may be used to determine a particular operational condition of the internal combustion engine such that the onboard fuel can be sent to one or more combustion chambers within the internal combustion engine without first passing through the separation unit, or instead to the separation unit in situations where the internal combustion engine may require an octane-rich or cetane-rich mixture.

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; a gas injector (98) which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve (79) configured to inject a liquid fuel into the cylinder for combustion. At the time of switching the operation mode from one to another between a gas mode and a diesel mode, a supply amount of a first fuel to be supplied in a post-switching operation mode is increased to a switching threshold value through an increase control which monotonously increases the supply amount, and then is controlled by a speed-governing control based on the engine rotation number. The switching threshold value is set based on the engine rotation number or the engine load.

A method for determining failure of an electromechanically actuated gas shut off valve includes sensing and recording a gas fuel rail pressure and a boost pressure from an air intake manifold at a first time after the dual fuel engine has been started. The method includes opening the gas shut off valve at a second time, holding the gas shut off valve in its open state, and then closing the gas shut off valve after a predetermined interval at a third time. The method includes comparing an actual gas rail pressure decay rate to a threshold gas rail pressure decay rate for the predetermined interval, and determining failure of the gas shut off valve when the actual gas rail pressure decay rate is less than the threshold gas rail pressure decay rate. Upon determining failure of the gas shut off valve, the method also includes initiating a mitigating action.

A vehicular propulsion system, a vehicular fuel system and a method of operating an internal combustion engine. A separation unit that makes up a part of the fuel system includes one or more adsorbent-based chambers such that the separation unit may selectively receive and separate at least a portion of onboard fuel into octane-enhanced and cetane-enhanced components. Regeneration of an adsorbate takes place through a heat exchange relation with existing system infrastructure. A controller may be used to determine a particular operational condition of the internal combustion engine such that the onboard fuel can be sent to one or more combustion chambers within the internal combustion engine without first passing through the separation unit, or instead to the separation unit in situations where the internal combustion engine may require an octane-rich or cetane-rich mixture, where adsorbed and remainder portions taken from the separation unit may be stored in separate tanks for later mixing and use within the combustion chamber.

A vehicular propulsion system, a vehicular fuel system and a method of operating an internal combustion engine. A separation unit that makes up a part of the fuel system includes one or more adsorbent-based chambers such that the separation unit may selectively receive and separate at least a portion of onboard fuel into octane-enhanced and cetane-enhanced fuel components. A supply tank includes three compartments where the first contains the onboard fuel, the second receives a vaporized adsorbate from the separation unit and condenses at least a part of it into one of an octane-rich fuel component or a cetane-rich fuel component, while the third may either store the condensed and enriched fuel component or help condense more of the vaporized adsorbate. The condensing takes place through heat exchange between the onboard fuel and the vaporized adsorbate that are present within the various compartments of the supply tank. A controller may be used to determine a particular operational condition of the internal combustion engine such that the onboard fuel can be sent to one or more combustion chambers within the internal combustion engine without first passing through the separation unit, or instead to the separation unit in situations where the internal combustion engine may require an octane-rich or cetane-rich mixture.

An internal combustion engine in which a fuel reforming operation in a fuel reformation cylinder (2) is not executed when a gas temperature of a fuel reformation chamber (23) at a time point when a piston (22) in the fuel reformation cylinder (2) reaches a compression top dead point is estimated to fall short of a reforming operation allowable lower limit gas temperature set based on a lower limit value of a reforming reaction enabling temperature. For example, fuel is supplied from an injector (25) so that an equivalence ratio in the fuel reformation chamber (23) is less than 1. Alternatively, the fuel supply from an injector (25) is stopped. This way, a supply of non-reformed fuel from the fuel reformation cylinder (2) to an output cylinder (3) can be avoided, and knocking in the output cylinder (3) can be avoided.

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.

A method for operating a dual-fuel internal combustion engine, having an intake path and an engine having a number of cylinders. In the method the engine is operated in a first operating state in diesel operation with diesel or another liquid fuel, and in a second operating state in gas operation with gas as fuel in a charge mixture, and switching between diesel operation and gas operation takes place in a switchover range determined, in particular predetermined, by switchover operating parameters.

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.