Prediction of traction in EHL contacts operating in the linear isothermal region

Sammanfattning: The vehicle industry plays an important role in moving people and goods all over the world. Unfortunately, the vehicular transportation has a huge (negative) impact on the climate. Improved fuel-efficient vehicle technologies are therefore required to reduce emissions and address environmental concerns. The introduction of alternative fuels and the use of high-pressure fuel injection systems in vehicle engines are some of the approaches that are employed to enhance the fuel efficiency of automobiles. However, in the case of high-pressure fuel injection systems, the tribological interfaces such as those of cam–roller followers are subjected to severe operating conditions (including high contact pressures and sliding motion) and consequently high frictional losses and risk of wear-related failures. This thesis’s objective is to establish a prediction formula for the traction coefficient slope to analyze the motion of the roller follower. This prediction formula is derived based on numerical calculations performed using a fully-coupled finite-element based model of the elliptical elastohydrodynamically lubricated contact specifically designed for operational conditions within the isothermal linear regime.