Search Results

Small gasoline engines are used in motorcycles and handheld machinery, because of their high power density, low cost and compact design. The reduction of hydrocarbon emissions and fuel consumption is an important factor regarding the upcoming emission standards and operational expenses. The scavenging process of the two-stroke engine causes scavenging losses. A reduction in hydrocarbon emissions due to scavenging losses can be achieved through inner mixture formation using direct injection (DI). The time frame for fuel vaporization is limited using two-stroke SI engines by the high number of revolutions. A high pressure DI system was used to offer fast and accurate injections. An injection pressure of up to 140 MPa was provided by a common rail system, built out of components normally used in automotive engineering. A standard electromagnetic injector is applied for the fuel injection. This injection unit is dimensioned for multi-point injections in diesel engines.

Natural vegetable oil like rape seed oil is a potential substitute for regular fuel for diesel engines. Compared to other biogen fuels like rape seed methyl ester (RME), pure rape seed oil is neutral towards groundwater and it needs considerably less energy and additives for production. Different physical properties of rape seed oil compared to Diesel fuel are the reason why conventional Diesel engines can hardly be used satisfactorily with rape seed oil without being modified. Poor exhaust-emission behavior is caused by the incomplete combustion. Due to poor spray atomization of vegetable oil, an increased fuel entrainment in the lubricating oil, carbonization in the combustion chamber and deposits at injectors and valves are further drawbacks of injection systems designed for conventional diesel fuel. The preheating of this fuel can solve some problems.