Multi-Fuel Combustion Methods, Devices and Engines Using the Same

An internal combustion engine composing:

• at least one fuel injector capable of producing jets with variable spray angles, a combustion chamber, a piston, a cylinder, and a cylinder head with intake and exhaust valves, wherein it has means to inject fuels with different spray angles at different injection timings to distribute fuel in combustion chamber spaces, to control quantity of fuel for premixed mixture formation and fuel stratification formation for different engine speeds and loads.

A method of combustion, comprising steps of:

• (i) determining fuel injection timings and quantities according to engine speeds and engine loads, (ii) direct injecting fuels into combustion chamber by varying injection spray angles based on injection timings, wherein narrower injection spray angles are used for early and post injections when the engine piston is away from TDC, and wider injection spray angles are used for injections when the engine piston is closing to engine top dead center (TDC), and (iii) using the narrower spray angle jets for generating early homogeneous charge, and wider spray angle jets for generating locally stratified late charges to couple with spark plug to ensure ignition stability.

An internal combustion engine composing:

• at least one fuel injector capable of producing variable spray angles, a combustion chamber having at least two divided chamber spaces on piston top, a piston, a cylinder, and a cylinder head with intake and exhaust valves, a spark plug, the said engine is operated such that it forms lean homogeneous mixture with the said variable orifice injector by activating its narrower spray angle jets for early injections, and it forms minor mixture stratification by activating its wider spray angle small jets for late injections, while the said small jets are coupled with said spark plug to form optimized mixture to ensure ignition stability.