Recent advances in the powertrain design of gasoline engines to meet environmental regulations have posed new challenges to the engine oil development. Smaller displacement engines, often with turbochargers, developed to meet higher fuel economy standards demand higher performance engine oils in conventional areas (oxidation and deposit control, fuel economy), and completely new areas (Low-Speed Pre-ignition [LSPI], turbocharger performance). Formulating engine oils which can simultaneously meet these competing demands will become more complex with increasing performance requirements.
Of particular interest for upcoming engine oil development is the phenomenon of low speed pre-ignition (LSPI). LSPI is an abnormal combustion event in which lubricating oil has been observed to play a role. This phenomenon is restricting automakers when operating their engines at high loads and low speed, which in turn is preventing the engine from operating at the most efficient conditions with respect to emissions and fuel economy.
Currently there are a number of different LSPI engine tests, using different hardware, operating conditions, and criteria to determine when LSPI events have occurred. In this presentation, a comparison of different LSPI tests will be made based on Oronite's extensive research work in this area. This comparison will highlight the differences in test severity and appetite while examining similar lubricant systems across different engine platforms and test conditions.