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Concerns such as depletion of petroleum fuels and global warming are placing more severe demands on internal combustion engines each year for reduced fuel consumption and CO₂ emissions. Countries around the world have set regulations that drastically reduce CO₂ emissions from vehicle exhaust. In order to meet these requirements, various new engine technologies are being developed. One of the technologies to cut CO₂ emissions of the SI engine is the combination of reduced displacement, high compression ratio, forced induction, and direct fuel injection. But in this downsized engine, abnormal combustion, which occurs under the condition of low speed and high intake pressure, is a serious problem. It has been referred to as Super Knock, Mega Knock or Low Speed Pre-Ignition (LSPI). In this paper, we use the term Super Knock. Many research institutions and car manufactures have been investigating this abnormal combustion, but the exact cause is still unknown.

Through CAE (Computer Aided Engineering) analysis, a method in verifying the reliability of wire harnesses has been developed. The relative displacement of the engine causes the battery cable to bend repeatedly; this may result in cable breakage. By investigating the breakage mechanism of battery cables, we have found a correlation between the strain change and cable breakage. Furthermore, the dynamic profile through CAE analysis has been established, and it is also possible to calculate its strain. Using this method, we can limit the amount of actual tests and predict the bending life of battery cables.

We developed a method to simulate the bending reliability with the aim of shortening the development time of wiring harnesses and achieving reliability in the initial stages of development. PVC-insulated wires are generally used in automobiles. Wire breakage due to repeated bending occurs easier at low temperature than at room temperature. Research showed us that we can estimate the number of bends until wire breakage at low temperature (bending life) from the amount of change in the strain in the wire insulation. Further, by using CAE analysis technology, it is possible to estimate the bending life of complex wire harnesses. This has greatly reduced the time and effort needed to perform evaluation compared with conventional evaluation tests.