The aerodynamic inefficiencies of motor vehicle cooling systems are generally of secondary importance to their production costs. However, the advent of the inexpensive moulded fan has meant that an improvement in cooling system aerodynamics can be more readily achieved which could reduce costs and radiator sizes, with the additional benefits of predictable performance and improved economy. In the investigation described, the design objective was to meet the top gear cooling targets entirely with ram-induced airflow, and to design the engine driven fan so that it consumed negligible power for top gear conditions, whilst being capable of meeting the cooling targets in the intermediate gear ratios. The work divided itself into the following three sections: (1) The prediction and achievement of the maximum ram-induced airflows. (2) Designing the cooling fan to be effectively free-wheeling and, therefore, consuming negligible power during top gear motoring, and to measure the performance of the resulting fan throughout the ram and fan assisted airflow regimes. (3) Designing and predicting the performance of a cooling system which was subsequently built and installed in a test vehicle in order to check its performance and making an overall comparison with regard to the original system. The paper shows that the design objectives were closely achieved. The 1·7 litre test vehicle was cooled satisfactorily with a one foot square radiator with the expenditure of only 0·9 hp in the cooling system when travelling at 70 mile/h.
Design and Modification of Radiator in I.C. Engine Cooling System for Maximizing Efficiency and Life