Optimized alcohol and plasma enhanced prechambers for engines powered by gasoline and other fuels are used to increase the range of prechamber operation and to reduce soot. The increased prechamber capability is employed to extend the limit of lean operation of the engines. It can also be used to extend the limit of heavy EGR operation and to enable higher RPM operation. The amount of alcohol used in the prechamber is preferably less than 2% of the fuel that is used in the engine cylinder. The alcohol for the prechamber can be entirely provided by onboard separation from a gasoline-alcohol fuel mixture.

Optimized alcohol and plasma enhanced prechambers for engines powered by gasoline and other fuels are used to increase the range of prechamber operation and to reduce soot. The increased prechamber capability is employed to extend the limit of lean operation of the engines. It can also be used to extend the limit of heavy EGR operation and to enable higher RPM operation. The amount of alcohol used in the prechamber is preferably less than 2% of the fuel that is used in the engine cylinder. The alcohol for the prechamber can be entirely provided by onboard separation from a gasoline-alcohol fuel mixture.

A variable displacement pump includes: an urging mechanism which includes two spring members; an electromagnetic switching valve which is arranged to connect the second control chamber and the discharge portion in an energized state, and to connect the second control chamber and the low pressure chamber in a deenergized state; and a control valve which is actuated by the pressure of the discharge portion, and which is arranged to decrease the pressure within the second control chamber when the pressure of the discharge portion becomes equal to or greater than a predetermined pressure.

A propulsion device for vehicles includes a device for the partial oxidation of fuel, a fuel tank and a diesel internal combustion engine. The device for the partial oxidation of fuel is in fluid connection with the fuel tank and the diesel internal combustion engine, with the result that at least some of the fuel carried in the vehicle is taken for partial oxidation before combustion in the diesel internal combustion engine. A method for operating such propulsion devices using partially oxidized fuel in the propulsion devices reduces soot emissions.

A propulsion device for vehicles includes a device for the partial oxidation of fuel, a fuel tank and a diesel internal combustion engine. The device for the partial oxidation of fuel is in fluid connection with the fuel tank and the diesel internal combustion engine, with the result that at least some of the fuel carried in the vehicle is taken for partial oxidation before combustion in the diesel internal combustion engine. A method for operating such propulsion devices using partially oxidized fuel in the propulsion devices reduces soot emissions.

A process for generating a main fuel composition comprising methanol and water and not more than 20% by weight dimethyl ether, and a fumigant comprising dimethyl ether, the process comprising: providing a pre-fuel composition comprising methanol and dimethyl ether, adding water to the pre-fuel composition to cause or aid evaporation of at least a portion of the dimethyl ether from the pre-fuel composition, collecting the portion of dimethyl ether evaporated from the pre-fuel composition for use as a fumigant, and using the remainder of the pre-fuel composition comprising methanol and water as a main fuel composition. The water may be at a temperature above ambient.

A process for generating a main fuel composition comprising methanol and water and not more than 20% by weight dimethyl ether, and a fumigant comprising dimethyl ether, the process comprising: providing a pre-fuel composition comprising methanol and dimethyl ether, adding water to the pre-fuel composition to cause or aid evaporation of at least a portion of the dimethyl ether from the pre-fuel composition, collecting the portion of dimethyl ether evaporated from the pre-fuel composition for use as a fumigant, and using the remainder of the pre-fuel composition comprising methanol and water as a main fuel composition. The water may be at a temperature above ambient.