HEAT TRANSFER THROUGH THE OIL FILM AND ITS EFFECT ON CONNECTING ROD BEARING TEMPERATURE

Abstract

The present paper was focused on the heat transfer rate through the main bearing of single and four cylinder engines using fresh (new) and used oil at different rotational speed. The experimental study was carried at I.C. Engine laboratory College of Engineering Technology Hoon, Libya. The results show that for four-cylinder engine, and at a engine rpm. more than 2500 rpm, it was found that the heat absorbed by the oil increases approximately 10% compared with the used oil. The oil condition i.e. ( used or new ) had a very small affect on bearing temperature. Comparing the new oil with the used oil it was obtained that increasing the engine rpms by 1000 rpm increases the heat transferred by the new oil approximately  40%, while the overall heat transfer coefficient increases by approximately 25% and the bearing temperature increases by approximately 10%. It is concluded that the new oil plays a positive role in heat transfer process and in protecting the bearing from frictional wear.

Key worlds: Heat transfer, connecting rod bearing, oil film, oil temperature.