Search Results

As direct injection technology in gasoline engines has become increasingly sophisticated to seek better performance, even a small amount of deposit can have a negative effect on the functionality of injectors. Against such a background, gasoline with effective additives is expected to fix this issue, however, the clean-up and keep-clean processes are not fully understood. In this study, a direct injector fouling test has been developed in order to inspect in more detail injector fouling phenomena in gasoline engines. The test engine used was a 2012 downsized supercharged direct injection spark ignition (DISI) engine equipped with an injector of maximum 15MPa injection pressure. The test fuel consisted of one regular grade gasoline (RG) and three premium grade gasoline with different concentrations of detergent.

Investigation of both intake valve deposit (IVD) formation tendency and the effect of surrounding conditions (e.g. atmospheric temperature) on IVD formation was conducted using poly aromatics-rich gasoline in a port fuel injected (PFI) engine. The IVD mostly consisted of carbonaceous deposit and this was shown to be derived from the heavier poly aromatic fuel molecules and engine oil. Analysis also indicated that some metals in the deposit structure came from additives of lubricating oil and the wear and/or corrosion within the engine. In this engine test, there was a significant effect of room temperature where higher room temperatures correlated with higher levels of IVDs. These results illustrate the importance of the surrounding condition in order to understand the IVD issues, higher IVDs weights will result under hotter driving (e.g. in summer) condition.