Development of a Floating-Liner Engine for Improving the Mechanical Efficiency of High Performance Engines 2006-01-3636

Engine friction typically accounts for 10 - 20 % of the power output of an engine, and friction in the power cylinder assembly is responsible for 50 % or more of the total engine friction. Hence, improvements to this assembly are critical for maximizing mechanical efficiency in high-performance and race engines. Many strategies have been developed and are currently being employed with the intent of reducing engine friction and extracting additional engine power. However, quantitative proof of their effectiveness has been very limited. This paper discusses the design and development of a research grade ‘floating-liner’ engine for measuring the friction forces within the power cylinder assembly of a high-speed internal combustion engine. The key attributes that set this motored floating liner engine apart from others include: simplified liner-piston exchange to minimize time and cost of testing, multi-axial force measurement, and the high speed capabilities of the force transducers and acquisition system, allowing force measurement at a crankshaft resolution of 0.5 degrees. Thus, the characteristics of this floating-liner engine are suitable for simulating high-speed, high-performance engines and quantifying the piston-cylinder friction in such engines.