Development of a Compression Pressurized Direct Fuel Injection System for Retrofit to Two-Stroke Engines

Small displacement carbureted, crankcase-scavenged, two-stroke engines are commonly used for transportation needs in developing countries (Iyer 2000). The high emissions characteristic of this engine design creates localized acute air pollution problems and contributes significantly to global air pollution (Gorham 2002). A compression pressurized direct fuel injection system (CPDI) has been proposed as a lower cost alternative to the common air blast direct injection system (ABDI). This paper describes the application of the CPDI system as a retrofit to a two-stroke engine typical of those used in “tricycle” transports in the Philippines. Power production, emissions, and fuel consumption for the original carbureted engine, the ABDI system and the CPDI system are also compared. The DI systems show a significant reduction in both hydrocarbons (88% reduction for the ABDI system and 86% reduction for the CPDI system) and carbon monoxide (49% for the air blast system, 83% for the compression pressurized system), and similar power compared to the carbureted engine.