A Review of Fuel, Intake and Combustion System Deposit Issues Relevant to 4-Stroke Gasoline Direct Fuel Injection Engines

The recent emergence of production Gasoline Direct Fuel Injection (GDFI) engines into the world markets offers the promise of both improved fuel economy and emissions for 4-stroke Spark Ignition (SI) engines. However with all new technologies there are new challenges that accompany them. The subjects of fuel and intake system and combustion chamber deposits in Port Fuel Injected (PFI) SI engines are well researched and documented.

Today only a small amount of specific research exists for GDFI engines [1,2,3,4]. In any case, based on available PFI deposit literature it is possible to make a number of observations about the likely GDFI fuel and intake system deposit issues and their effect on fuel economy, exhaust emissions and performance during a lifetime of service.