Search Results

This paper describes a study of the effects of oil composition on visible smoke, engine cleanliness, and piston anti-seizure performance. Two laboratory tests, termed the DSC (Differential Scanning Calorimeter) method, and the HTT (Hot Tube Test) are investigated as screening tests for two-cycle engine oils. Two types of oil were developed to comply with stringent Japanese oil requirements. Firstly, smokeless type oils formulated, with high concentrations of polybutenes were introduced to greatly reduce visible smoke from two-cycle engines of high specific output. Secondly, low-friction oils containing ester type synthetic base stocks were developed to achieve higher engine output in racing applications.

In Japan, turbocharged passenger cars have recently been introduced with increased improvements in fuel economy and engine performance. However, a turbocharger is driven by hot exhaust gas, so that an engine oil with superior thermal stability is required. After studying a turbocharged engine's thermal effects, two laboratory screening tests that correlate with dynamometer engine tests were established. These tests, termed the panel coking test and the high temperature panel corrosion test, enable one to evaluate base oils, additive components and viscosity index improvers for a given engine oil. Finally, a 10W-30 engine oil formulated by using these tests, showed superior deposit control and anticorrosion performance in the dynamometer engine test and actual driving conditions.

A high viscosity index (HVI) petroleum base stock (VI=125), which is produced by a severe hydrocracking process, has been used in formulating an advanced SAE 5W-30 oil meeting API SG, EC-II and current ILSAC performance requirements in order to demonstrate potential fuel economy benefits of this oil. The oil was formulated by blending the HVI base stock with a small amount of a solvent-refined base stock to obtain an “optimal aromaticity”, a dispersant VI improver, an optimized combination of detergent and inhibitor, and a conventional ashless friction modifier. The fuel economy performance of this oil has been compared to that of a similarly formulated solvent-refined SAE 5W-30 oil using the Sequence VI test, a motored engine friction test, a new fired/motored friction test, and the EPA road simulator fuel economy test. The SAE 5W-30 HVI oil exhibited an improved fuel economy performance in the above tests, despite of higher HTHS viscosity of the HVI oil.