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In this work, the connecting rod bearing seizures as one of the problems latent to the high-output, high-speed engines are investigated. Studies are conducted on the evaluation of anti-seizure properties of a single connecting rod bearing installed in the test rig as well as in commercial engines. As the results of the former study, the bearing wear is affected by the rod surface roughness (Rmax ) and the oil temperature (viscosity). Further, frequent metal to metal contacts of bearings are observed by the electrical measuring apparatus under higher temperature, and full load conditions. While in the latter, it is found the total heat generated of the bearing is the important factor affective to the bearing seizures, and can be analyzed by using PV value, rod surface roughness and oil viscosity.

In the cities of the U.S. the worsening ozone problem has attracted attention and prompted reinforcement of regulations against emissions of hydrocarbons (HC) from automobiles. To cope with this situation, a reduction of HC is a vital challenge for the automotive industry. HC emission comes mainly from a cold engine, which usually uses a richer air-fuel mixture to achieve stable combustion and secure good driveability. The purpose of this paper is to show that using a engine with variable valv1e timing and lift system (VTEC) (1)∼(2) it is possible to reduce considerably HC emission in cold-start conditions. In other words, it is able to employ a leaner mixture than in existing engines (A/F=15.5) by using the VTEC system to alter the valve timing and lift according to various driving conditions, thereby considerably reducing HC emissions due to the improvement and stabilization of engine combustion.