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One of the demands regarding reciprocating seals is to minimize the leakage from machineries due to global environmental issue. Especially in these years, rising in efficiency and downsizing of the machineries make the operating conditions of the seals severer than ever. Therefore, it becomes more important to know the sealing performance with high accuracy under actual operating conditions. In order to meet the request, a new method based on visualization and spectroscopy is presented. In this paper the description of the technique and the first results obtained with general reciprocating seals are shown.

Seal rings are used as shaft seals in automatic transmissions, where they act as a dam to direct pressurized fluid flow to hydraulic circuits. Conventionally, cast-iron seal rings were used, but over the past two decades, this material has been switched to resins like PTFE and PEEK to satisfy performance requirements such as low leakage and low frictional torque. However in using resin seal rings, the shaft sometimes undergoes the so-called three body abrasive wear due to invasion of hard particles, such as wear particles and dust, into the sliding portion between the seal ring and the shaft. To prevent such wear of the shaft, it is important to prevent invasion of hard particles into the sliding portion, and also to promptly discharge hard particles from the sliding portion. We therefore designed a seal ring taking into consideration these needs and investigated its shaft wear reduction effects.

A dynamic and hydraulic analysis on common-rail injectors using Bond Graph Simulation Program (BGSP) was made. BGSP is based on the Bond Graph method of hydraulic system modeling, which has an advantage in handling multi-energy domains such as common-rail fuel injection system. After the verification of BGSP, analysis was made on a few concepts of common-rail injectors. Pressure traces of the control chamber for each injector concept was obtained. Through these analysis, the key phenomena were identified. Although the optimization has not been done yet, compatibility between initial injection rate shaping and rapid closing on a common-rail fuel injector was discussed. As a result, common-rail injectors with a “variable inlet orifice” concept have better compatibility.