The Impact of Inlet Valve Deposits on PFI Gasoline SI Engines – Quantified Effects on Fuel Consumption

Control of inlet valve deposit (IVD) formation in port fuel injected (PFI) gasoline spark ignition (SI) engines has been an on-going concern due to the deleterious impact that this material can have on engine performance (power, acceleration times, drivability and fuel consumption). However, decoupling the effects of IVD formation from the multiplicity of other changing engine parameters whilst quantifying the impacts on engine behavior has remained a challenging task to accomplish. A dedicated experimental methodology is presented that has been specifically designed to address this issue. It successfully decouples and quantifies those engine performance impacts that are attributable to IVD formation. Results are presented demonstrating the deleterious impact of IVD formation on fuel consumption in a PFI SI engine.