Investigation of Automotive IC Engine Water Pump Housing Failure and Resolution through Experimental Modal Analysis and Study of Vibration Characteristics of the System

Cooling system for an IC engine, consisting of the Water pump (WP), Radiator and Fan, plays an important role in maintaining thermal efficiency of the engine and protects the engine from overheating. Based on the vehicle application requirement, Fan will be mounted directly either on Crankshaft or WP pulley. But wherever increase in Fan speed ratio are in demand, it is preferred to mount the Fan on WP pulley. So it important to understand the WP housing structural strength with respect to vibration loads contributed from Radiator Fan assembly. This paper presents investigation of Failure of WP Housing during engine validation at engine test bed with Electronic Viscous Fan, based on the different operating conditions of the engine and fan as per the validation cycle. While the accessories are loading and the corresponding stresses are high when the fan is engaged. But in the current case, the failure of WP housing happened only during Fan clutch disengaged condition. Experimental Frequency Response Function (FRF) were carried out to identify the mode shapes and resonant frequencies. Vibration on WP housing were compared with Fan engaged and disengaged condition to identify the critical frequency ranges that minimize vibrational impacts on the WP housing. The results indicate a significant correlation between Fan Blade Pass Frequency (FBPF) and vibrational amplitude on WP housing. By optimizing FBPF, it is successfully mitigated high vibration levels, thereby enhancing the structural integrity and operational reliability of the WP housing. In addition, the results of crack initiation points, strain gauge measurements, structural and modal analyses are examined to enhance the WP housing strength.