Online Technique of Measuring Real Time Friction in Engine Valve Train.

Abstract

Reduction in power loses, fuel economy and check and control on emissions are the key common drivers of automotive industry. Improvement of technologies and lubricant formulations are considered to enhance engine performance and in order to do so an extensive demand for comprehensive experimental work and precise measurement tools are required to validate the effectiveness of these technologies. In roller follower valve train configuration, cam and roller contact surfaces are largely responsible for power loses as friction between two surfaces at cam roller interface based on different operating conditions and lubricant rheology. In this research project, a real production gasoline engine with end pivoted roller follower which is widely used in today’s passenger vehicles has been developed following new development techniques using advanced sensor technology to measure the friction at a single cam roller interface following actual engine environment. Following technique avoids any major modifications to the roller and cam while observing their behavior at live operating engine. This technique studies the friction at single cam lobe and follower by considering multiple variables such as oil pressure, operating temperature, lubricant type and rotation speed. A good agreement between theoretical data and experimental evidence also established. It is strongly believed that the obtained realistic data will provide flexibility in validating the mathematical models on cam trains and also beneficial for engine modifications and lubricant formulations in present efforts to improve engine tribological efficiency.