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The major aim of this study is to investigate the tribofilm formation and friction-speed characteristics of ZnDTP in the presence of other lubricant additives. Simultaneous measurement of friction and electrical conductivity were employed using ZnDTP and several kinds of functionally different additives. Several analyses of friction surfaces were also carried out in order to measure the reaction film thickness and investigate the chemical composition of this film. It was demonstrated that the presence of each additive with ZnDTP prevented the formation of a ZnDTP tribofilm and thereby could provide lower friction than ZnDTP alone.

In resent years, dynamic studies of valve mechanisms in the internal combustion engine have dealt with peculiar phenomena such as valve jump or bounce which occurs at high speed operation. These studies have contributed to the reduction of valve mechanism problems. However, one of the most severe problems is the wear of the valve face or seat. The dynamic study of valve mechanisms can be applied to this problem. It can be concluded that the impulse force working on the valve at the closing moment is the most effective factor to influence this problem. But, this impulse force has not been closely understood from the point of view of valve vibration mechanisms. This paper describes how the five mass model can simulate the valve mechanisms dynamically, and express the impulse force rather than the valve motion or pushrod force used previously.

Nowadays, most manufacturers are looking for the improvement of lightweight parts and other components in the automobile field. Carbon fiber and glass fiber are the most effective materials for their requirement to reduce the weight in vehicles due to their light weight and high tensile strength. The diameter of carbon fiber is 6 μm while glass fiber diameter is 17 μm. The mechanical tensile force of carbon fiber and glass fiber are 430 N and 290 N respectively on fiber alone without matrix. Carbon fibers are gradually smaller in each filament due to tensile force. Approximately 5 mm are elongated for both carbon fiber and glass fiber in tensile test report. In current research, characteristic and tensile force of carbon fiber and glass fiber were investigated by using electron microscopy, Raman spectroscopy and XRD.

The soot contamination in used engine oils of diesel engine vehicles was about 1% by weight. The soot and metal wear particle sizes might be in the range of 0-1 µm and 1-25 µm, respectively. The characteristics of soot affecting on metal wear was investigated. Soot particle contamination in diesel engine oil was simulated using carbon black. Micro-nanostructure of soot particles were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and laser diffraction spectroscopy (LDS). The metal wear behavior was studied by means of a Four-Ball tribology test with wear measured. Wear roughness in micro-scale was investigated by high resolution optical microscopy (OM) , 3D rendering optical technique and SEM image processing method. It was found that the ball wear scar diameter increased proportionally to the soot primary particle size. The effect of biodiesel contamination were also increasing in wear scar diameter.