Development of a two stroke direct injection jet ignition compressed natural gas engine

A traditional two stroke engine with crankcase scavenging also adopting an exhaust reed valve and lamellar intake is modified to accommodate a high pressure Compressed Natural Gas (CNG) direct injector and has the traditional spark plug replaced by a jet ignition device of the same thread. The jet ignition device is a pre-chamber accommodating a Gasoline Direct Injection (GDI) injector operated with CNG and an 8 mm racing spark plug. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices. The CNG is injected after the exhaust post closes. The GDI injector operated with CNG introduces a slightly rich amount of fuel in the pre-chamber. The spark plug discharge initiates the pre-chamber combustion that then propagates to the main chamber though multiple jets of high energy partially burned hot combustion products that quickly ignite the main chamber mixtures. The Computer Aided Design (CAD) model of the engine including the jet ignition device is discussed in detail. The Computer Aided Engineering (CAE) model of the engine is shown to produce efficiencies well in excess of 35% in the area of best operation. The load is controlled by fine tuning the injection and ignition events and increasing the overall air-fuel ratio. The solution offers an opportunity to produce an efficient alternative to four stroke engines with improved power density, running on alternative fuel having larger availability and better combustion properties and reduced pollution than traditional diesel and gasoline fuels.