the engine 50 the compression piston 72 pressurizes the air charge and drives the air charge into the one or more crossover passages 78 one or more check valves 228 in the one or more crossover passages 78 preferably one check valve 228 in each crossover passage 78 control flow of compressed air into an air processing system 210 through one or more air input lines 224 the air input lines 224 can preferably connect directly from the crossover passage s 78 to the air processing system 210 though check valves are utilized for this embodiment other appropriately designed valves may also be used e g poppet valves alternatively one or more small orifices preferably one orifice in each crossover passage 78 can be used in place of the one or more check valves 228 orifice s can generally be advantageous because of their potentially improved cost and packaging considerations in relation to check valves alternatively to air supply line 224 or in combination with air supply line 224 a second air supply line 226 can be used to supply compressed air to the air processing system 210 the second air supply line 226 connects the compression cylinder 66 directly i e not through one or more crossover passages 78 to the air processing system 210 as shown in fig3 via a check valve 230 in other words the compression piston 72 pressurizes an air charge and drives some or all of the air charge into the air supply line 226 through valve 230 thereby bypassing the.