Using a generative design method, we developed an ideal shape that achieves both weight saving and heat dissipation while withstanding vibration and stress: A concept model of an ECU that is directly mounted on the engine, and an eco-friendly design that improves fuel economy and reduces material use. The design achieves about 12% weight saving versus conventional enclosures and achieves equivalent cooling despite the much smaller volume. Finally, the design language is applicable to other models, so that the entire ECU Series can make a positive contribution.