Search Results

It has long been understood that the piston assembly of the internal combustion engine accounts for a significant proportion of total engine friction. Modern engines are required to have better fuel economy without sacrificing durability. The pursuit of better fuel economy drives trends like downsizing, turbocharging and direct injection fuelling systems that increase cylinder pressures and create a more arduous operating environment for the piston ring / cylinder bore tribocouple. The power-cylinder lubricant is therefore put under increased stress as modern engine technology continues to evolve. The conventional approach to investigating fundamental power-cylinder tribology employs bench-tests founded on assumptions which allow for simplification of experimental conditions.

Over several years, a fuel economy test measurement technique has been developed to highlight the magnitude of benefits expected in real world applications of different heavy-duty vehicle (HDV) engine oils in an operating vehicle. This method provides discriminatory results using an alternative to the widely used gravimetric fuel measurement methodology of Brake Specific Fuel Consumption (BSFC), in order to measure gains of <2% in a more repeatable manner. For the results to prove meaningful to the wider commercial audience, such as vehicle operators, original equipment manufacturers and oil providers, the systemic test vehicle operating conditions need to closely represent on-road conditions experienced on a daily basis by long haul, heavy duty diesel vehicles. This paper describes the parameters, necessary measures and methodologies required to record real world data and create representative proving ground test cycles.