Copyright © 2003 SAE International ABSTRACT An air-conditioner compressor-mounting bracket is a structural component of an engine, on which bolts attach an air-conditioner compressor. In this paper, the shape of the air-conditioner compressor-mounting bracket of a passenger car is optimized using a finite element software, and the optimized bracket is manufactured and verified by tests. An objective function for the shape optimization of the bracket is the weight of the bracket. Two design constraints on the bracket are the first resonant frequency of the compressor assembly and the need not to fracture during the workbench durability test. The compressor assembly, which consists of a compressor, a bracket and connection bolts, is modeled using finite elements. The bracket is modeled by solid elements and the swash-plate-type compressor is represented by rigid masses and beam elements in order to consider the elastic effects of the compressor. For simulation of the dynamics stresses in the durability test, the large mass method is used. The design variable is the shape of the bracket including thickness profiles of the front and back surfaces of the bracket, radius of outer boltholes, and side edge profiles. The coordinates of the FE nodes control the shape parameters. Optimal shapes of the bracket are obtained by using SOL200 of MSC/NASTRAN. The verification tests are conducted on the workbench and in a full vehicle. Test results shows that the developed optimization procedure of the bracket are valid in the complex real world. INTRODUCTION Many peripheral pieces of equipment are attached on an engine block. Among them, the air-conditioner compressor is one of the largest components of the powertrain in a passenger car. An air-conditioner compressor-mounting bracket is a structural component of the engine, on which bolts attach the air-conditioner compressor. The compressor-mounting bracket supports the air-conditioner compressor and the dynamic characteristics of the compressor assembly mainly depend on that of the bracket. The compressor- mounting bracket experiences severe dynamic loads during the engine operation because the bracket is fixed by bolts directly to the engine block. From a designer’s viewpoint, fatigue failure of the bracket should not occur during the car’s life. Furthermore, resonant frequencies of the compressor assembly should not exist in the engine-operation range because vibrations of the compressor assembly can cause vibration and/or noise problems in the passenger compartment of the vehicle. Nowadays, development of components using CAE tools such as the finite element method has been a common tool in early design stages [1,2]. In addition, the shape and topology optimization technique is becoming a useful tool. In this paper, the shape of the air-conditioner compressor-mounting bracket of a passenger car is optimized using commercial finite element software, and the optimized results are confirmed by tests. ANALYSIS OF THE BRACKET The bracket is bolted on the engine block and other bolts connect the air-conditioner compressor and the bracket. To operate the swash-plate-type compressor, the power of the engine is transmitted through belts, which connect the belt pulley of the compressor and crankshaft of the engine. In this study, the authors are interested in the design of the bracket and assume that the designs of the compressor and engine block are fixed. There are two major quantities to be analyzed in order to design the compressor-mounting bracket. One is the resonant frequency of the compressor assembly and the other is the fatigue life of the bracket. First, the resonant frequency of the compressor assembly is very important 2003-01-1667 Optimal Shape Design of an Air-Conditioner Compressor- Mounting Bracket in a Passenger Car Doo-Ho Lee Dongeui University Jeong-Woo Chang Halla Climate Control Corp. Chan-Mook Kim Kookmin University