The automotive electronic control unit outputs control signals using electrical signals of various input sensors installed in the vehicle to control the state of the engine, automatic transmission, and electric power steering (EPS). These units are installed inside the vehicle or engine room, and the temperature rises and falls by several tens of degrees due to the heat of the engine and the self-heating of the electronic control unit. Therefore, it was exposed to a thermal fatigue environment due to the difference in the coefficient of thermal expansion between the components, which caused frequent component damage. Solder cracks due to thermal fatigue in electronic control units are a key failure mode. However, because of its great heat capacity, the electronic control unit for automobiles took a long time to attain the desired temperature of high or low, and as a result, the 1,000-cycle test for thermal fatigue life verification required 3,167 hours (or 4.4 months). Therefore, in this study, the thermal shock cycle test time for the verification of the thermal fatigue life of electronic control units for automobiles was reduced by dividing it into two types.

Domestic railway-maintenance technologies have been developed over more than 100 years of railway operation. Based on these technologies, we are striving to localize the vehicular parts, while the component localization is currently from 90-95%. Foreign manufacturers’ products, however, are still used in the manufacturing of major core components. Bearings are one of the key components in the support of the rotating shaft, and they are the essential components of major railway parts, like axles, electric motors, and gears, as they ensure the running stability of railway vehicles at high speeds. Among them, the axle bearings need to be protected against damage not only due to the possibility of a failure, but also to avoid railway accidents, so a high reliability and stability are required. Therefore, the durability test of axle bearings is both costly and time-consuming. In South Korea, the development of axle bearings has not occurred, but several test benches for a bearing-durability test have recently been developed. The characteristic curve was created using the temperature change according to the rotational speed of the bearing, and the acceleration index was obtained from this characteristic curve.