Piston and process for achieving controlled ignition and combustion of hydrocarbon fuels in internal combustion engines by generation and management of fuel radical species

A process of radical seeding of a charge in a combustion chamber of an air breathing reciprocating piston type internal combustion engine including a piston having a recess area at its crown and a fuel supply system arranged to supply fuel into the combustion chamber to carry out a combustion cycle including intake, compression, combustion, expansion and exhaust portions comprising:

• providing a generally toroidal shaped reaction chamber in the piston crown area adjacent the periphery of the recess and extending at least part way around the outer periphery of the recess area;
• providing the reaction chamber with a continuous slot orifice directed tangentially towards one side of the chamber and curved inner sidewalls so that a radial vortical flow is induced in the reaction chamber when fluid flows into the reaction chamber from the recess area during each compression stroke of the piston, with the vortical flow arranged so as to retain the fluid in the reaction chamber;
• selecting slot orifice dimensions, configuration and location such that combustion flames from the combustion chamber are quenched by the slot orifice before they can extend into the reaction chamber and such that inflow and outflow of compressible gases to and from the reaction chamber from and to the recess area are choked due to differential pressure conditions existing across the slot orifice during part of the expansion, exhaust and compression portions of each combustion cycle, so that the pressure fluctuations in the reaction chamber always lag behind the pressure fluctuations in the combustion chamber and so that radicals generated in the reaction chamber during a combustion cycle are partially retained in the reaction chamber during the combustion, expansion and exhaust portions of the combustion cycle and are partially discharged into the recess area near the start of the compression portion of the next succeeding combustion cycle;
• carrying out each combustion cycle by directing at least a portion of the fuel for each cycle with air into the reaction chamber and partially reacting the fuel with air in the reaction chamber while the mixture is vortically swirled in intimate contact with the chamber sidewalls, and by discharging a portion of the radicals generated in the reaction chamber into the bottom lower half of the recess area under the choked outflow conditions recited in the previous step;
• carrying out the generation of radicals in the reaction chamber and controlling the generation of radicals within the reaction chamber in accordance with the formula:
• R.sub.out =R.sub.gen. +R.sub.in -R.sub.ret. .gtoreq.R.sub.crit.
• where:
• R.sub.out =radicals discharged from the reaction chamber into the piston recess area;
• R.sub.gen. =radicals generated during each combustion cycle in the reaction chamber;
• R.sub.in =seeded radicals returned to the reaction chamber from the combustion chamber during compression of a charge;
• R.sub.ret. =radicals retained in the reaction chamber;
• R.sub.crit. =the minimum quantity of radical species of fuel in the reaction chamber required to obtain preselected ignition and combustion characteristics of the charge each combustion cycle.