Development of Mechanical Gasoline Direct Injection (GDI) Engines for 4 Stroke Two Wheelers

                  The general demand in the market today is for two wheelers with excellent fuel economy, superb power performance and cleaner & greener emissions. But the actual situation is somewhat contrary in the sense that the two wheeler generally bought by the public have characteristics which include very high levels of pollution caused by scavenging losses, un-economical operation because of fresh charge losses, less scope for lean operation and no control on the engine once the valves have closed. Therefore the goal of this paper is to design an injection system to achieve optimum emission values and noise levels. In addition this paper looks at improving fuel consumption and drivability independent of the operating point, which is implemented by a mechanical variable injection timing system. For this, the effect of different head designs on the exhaust gas emissions is analyzed initially. Also a light weight and compact Aluminum housing is designed for the pump – follower junction. This is directly attached to the overhead camshaft. A new jerk type fuel injection pump was designed based on the differences in the physio-chemical properties of diesel and petrol. The characterization of the engine is done in carburetor mode for reference purpose. A characterization of the fuel injection pump was also carried out.