MAINSTREAM ENGINEERING CORP — Department of Defense SBIR Phase II: OSD13-PR1

Description

This effort is to develop a fast responding, light weight, direct injection system to operate within the fuels ignition delay time for UAS/UGS application. These systems must be applicable to engines that are 200 HP or less, either reciprocating or rotary. A technical challenge associated with the conversion of gasoline engines to heavy fuel (JP-8) is the avoidance of knock. An approach used to avoid knock is to operate within the fuels ignition delay time; hence to employ direct combustion chamber injection. The challenges of the reciprocating engine are to avoid end gas knock (auto ignition occurring in the end gas after spark) and to inject the fuel very late into the cycle. The challenges for the rotary engine are atomization and the avoidance of wall quenching due to its combustion chamber shape. Delaying the injection process causes higher pressure rise rates which can exceed the engines design capabilities. An injection system that offers fast response and multiple injections per cycle may alleviate excessive pressure rise and the avoidance of knock. Good combustion control eliminates many durability issues from overloading, shock, and combustion deposits. The shape of the combustion trace can be tailored through multiple injection pulses and combustion deposits can be controlled with better atomization and fuel patterns. Hence an injection system that offers fine atomization, fast response, and multiple injections per cycle is needed. System components are to include injectors, high pressure supply pump (1000 bar min), feed pump and controller with harness.