be used to further study intake opening size position and number it is presently understood that sizing intake opening 36 too small will not allow a sufficient quantity of fuel to enter shielded space 33 whereas sizing the intake opening too large can lead to excessive flow between shielded space 33 and the combustion chamber which can cause excessive cooling of igniter 32 and reduce pressure build up within shielded space 33 causing slower or less extensive penetration of the burning fuel air mixture that is propelled into the combustion chamber 0092 fig3 illustrates another preferred embodiment of ignition device 30 wherein discharge openings 38 u2032 are positioned in the dome shaped end of sleeve 34 u2032 an advantage of locating discharge openings 38 u2032 in the dome shaped end is that the length of ignition device 30 can be shorter than if the discharge openings were located in the cylindrical side walls as they are in the embodiment of fig2 with some piston head designs such as ones that employ a pip depending upon how far ignition device 30 protrudes into the combustion chamber a dimple can be formed in the piston head opposite ignition device 30 to prevent contact therebetween during engine operation 0094 fig3 also.