Development of a Compact and High-Performance Radiator for Thermal Management of Environmentally-Friendly Cars

To comply with increasing fuel efficiency regulations, a low temperature radiator (LT radiator) is required to cool the charge-air system of a turbocharged engine. These engines are important to use for environmentally-friendly cars. Since heavy-duty and high-performance cars demand high cooling performance, the main radiator alone is typically insufficient in meeting the vehicle’s cooling requirements. An additional radiator installed in the front of the wheel-well is required to meet the extra cooling demand. In order to install this radiator in the front of the wheel-well, guaranteed performance in the limited packaging space and impact resistance of the leading tube edge are required. We developed the Supplementary Inner-Fin Radiator (SIR) which achieves the compact, high-performance, and durability requirements by use of an inner-fin tube (I/F tube). The purpose of this paper is to report our design approach and product specifications of the SIR. In particular, the impact resistance requirement is set from understanding the vehicle usage environment. This is an important consideration due to coolant leaks caused by damaged radiator tubes. First, we estimated the impact energy of 0.42 J from modeling a stone-impact environment with the conditions of a 7.7 mm sized stone and a vehicle speed of 130 km/h. The tube resistance target of 0.63 J was set in consideration of a safety factor. Second, we discovered that the stone hits the tube from the front-side when the radiator is placed in the front of the wheel-well, and so we analyzed the inner-fin tube from the viewpoints of shock absorption and deformation suppression. Finally, we confirmed that the SIR achieves this target of tube impact resistance (0.78 J > 0.63 J) by means of an impact bench test.