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Downsizing gasoline direct injection engine with turbo boost technology is the main trend for gasoline engine. However, with engine downsizing and ever increasing of power output, a new abnormal phenomenon, known as pre-ignition or super knock, occurs in turbocharged engines. Pre-ignition will cause very high in-cylinder pressure and high oscillations. In some circumstances, one cycle of severe pre-ignition may damage the piston or spark plug, which has a severe influence on engine performance and service life. So pre-ignition has raised lots of attention in both industry and academic society. More and more studies reveal that the auto-ignition of lubricants is the potential source for pre-ignition. The auto-ignition characteristics of different lubricants are studied. This paper focuses on the ignition delay of different lubricants in Controllable Active Thermo-Atmosphere (CATA) combustion system.

An anti-friction additive was studied in API SM 5W-30 oil. Its tribological performance was evaluated on a four-ball tester, SRV and MTM. This additive has been found to be an effective antifriction additive for lubricants. The investigation indicates that this additive possesses excellent energy saving and reducing friction characteristics in API SM 5W-30 lubricating oil.

Zinc dialkyldithiophosphates (ZDDPs) provide efficient and effective anti-wear, anti-oxidation and anti-corrosion properties in engine oil formulations. Two kinds of formulated engine oils were investigated including Oil 1 containing secondary ZDDPs, and Oil 2 containing primary/secondary ZDDPs. It revealed that different types of ZDDPs exhibits different volatilities and have different effects in the Sequence IIIG test. ZDDPs with higher molecular weight alcohols exhibit a relatively low volatility. The combination of primary/secondary ZDDPs exhibits higher phosphorus volatility in the Sequence IIIG, but have the same anti-wear protective behavior than that of the secondary ZDDPs in field tests. The field test results of phosphorus volatility and viscosity increase show encouraging agreement with the results of the Sequence IIIG test. However, the field test exhibits lower phosphorus volatility than the Sequence IIIG engine test.

Regulations to reduce emissions worldwide are the driving force behind the modifications that OEMs (Original engine manufactures) are making to their engine designs, which in turn drives the need of changes in lubricant requirements. To meet the emission standards, engine makers are turning to after-treatment devices that supplement EGR (Exhaust Gas Recirculation). In the United States, engines are being equipped with DPF (Diesel Particulate Filters), while in Europe SCR (Selective Catalytic Reduction) is favored. In China, technologies of engine design are also intended to meet the stricter regulations of emissions control. But different OEMs tend to favor different technologies depending on their own in-house technologies and that of their partners. So HDEO (Heavy-Duty Engine Oil) marketers in China must qualify their products to meet both API (American Petroleum Institute) licensing standards and individual OEM specifications.