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One of the authors has proposed to use the decay rate of EHRR, the effective heat release rate, d2Q/dθ2 as an index for the rapid local combustion [1]. In this study, EHRR profiles and the cylinder gas pressure oscillations of the low and high speed knock are analyzed by using this index. A delayed rapid local combustion, such as an autoignition with small burned mass fraction can be detected. In the cases of the low speed knock, it has been agreed that a rapid local combustion is an autoignition. Although whether the cylinder gas oscillation is provoked by an auto ignition in a certain cycle or not is an irregular phenomenon, the auto ignition takes place in almost all of the cycles in the knocking condition. Mixture mass fraction burned by an auto ignition is large. A small auto ignition may induce a secondary auto ignition, in many cases, mass burned by the secondary auto ignition is extremely large.

This paper reports on a new concept for static seal designs taking into consideration the surface roughness of sealing surfaces. The concept focuses on fluid penetration from the interstices between the seal and counterface caused by surface roughness. In the study, we investigated the relation between the leakage and surface roughness of the sealing surface of the elastomer seal. At the same time, we also analyzed the contact state of the elastomer seal based on the equations of Ishiwata et al. on deformation of elastomer surface into rough surfaces [1]. The micro-leakage testing machine (SMLA) developed by the authors was used to measure micro-leakage at high precision and in a short time [2]. The results showed that the sealing phenomena were related to the ratio of seal surface contact pressure Ps / elastic modulus of seal E, determined by the compression ratio of seals, and does not depend on the chemical structure and hardness of the elastomer used.

The correlation between the micro surface roughness and sealability of O-rings was experimentally analyzed. We developed a SMLA (Seal Micro Leakage Analyzer) for observing the contact of micro asperities using a micro-prism glass plate, and a micro-leakage measurement device for O-rings. Using the SMLA, the contact of micro asperities of O-rings surfaces ranging from 1.6 microns to 16.3 microns was clearly visualized. We also measured the contact area and leakage amount at the same time, and studied the sealing mechanism. The visualized images of the contact area were analyzed by image processing. The results showed that the micro asperites on the O-ring surfaces were squashed elastically to form a band which sealed in the fluid.

The flow behavior of rubber compounds inside a mold is very complicated including various phenomena such as heat transfer from the mold, wall slip and swell at the divergent cavity. A slit rheometer which can measure the flow behavior inside a mold during curing was developed. The rheometer has a window which enables the observation of the flow behavior directly under 50 MPa. The pressure loss gradient along the flow direction and shear viscosity were found to be independent on the degree of cure but wall slip was observed. The wall slip phenomena could not be explained by slip analysis, because plug flow occurred due to little effects of the poiseuille flow. The pressure behavior inside the slit could be well predicted by using the equation obtained by assuming stress relaxation of visoelastic fluid occurs without share along the wall. The stress relaxation phenomena were predicted by taking into account the short and log relaxation time.

In automotive plastic parts, bumpers are rather bigger parts and easy to be detached. And there is growing need to develop bumpers recycling technology. Now we developed the recycling technology for waste painted Super Olefin Polymer (SOP) bumpers from car dealers in production. This technology consists of discriminating from the repair in market by dyeing, and of melting SOP resin and hydrolysis of the paint film which are carried out simultaneously in a twin-screw extruder Reactive Processing System.

An experimental evaluation of the reliability of the Zeuch's method was carried out. The following were derived: 1) cavitation limits the minimum back pressure available; 2) the injection rate measured by the Zeuch's method agrees with that by the W.Bosch's method; 3) the effect of dynamic pressure of the injected fuel jet has a negligible effect on the pressure sensor which is attached to the chamber wall; and 4) the high-frequency noise after the end of injection observed in the Zeuch's measurement can be effectively removed by either a low-pass filter or an inverse Fourier transform processing.