Standardized Method for Vibration Testing of Engine Cooling Systems 931142
The purpose of this paper is to demonstrate practical applications of a standardized method for vibration testing of vehicle engine cooling modules and components based on the developed data collection scheme, the test data calibration and editing. In addition, some examples of collected road data analysis and simulated test creation will be discussed.
Moving vehicle vibrations are an important part of the dynamic environment of an engine cooling module which affects system durability. Several methods of vibration testing and real road condition simulation were developed to evaluate the cooling module durability and to assure the system long life in customer hands. The goal of simulated vibration testing is to recreate the dynamic load on the system which the vehicle ECM might see in real road conditions and which could produce cooling module failures during the vehicle life cycle. Direct simulation of the road conditions takes many days or even months and would not be acceptable for a testing laboratory running sophisticated dynamic equipment. An effective test should be completed in significantly shorter time using the method of accelerated dynamic simulation.
The engine cooling module (ECM) is an assembly of radiator, charge air cooler, automatic transmission oil cooler and condenser. In many cases the system includes a shroud with a fan and electric motor and, sometimes, coolant recovery bottles or auxiliary tanks. Some cooling modules are mounted rigidly to the frame or to the body of vehicles, but more and more frequently some type of mount isolators are provided to the assembly and its components. Vibration durability testing has become a routine procedure for both passenger car and heavy duty truck engine cooling module evaluation and a significant part of every ECM test specification. Vibration test specifications describe different dynamic conditions for cooling system testing. Today there are no mutually accepted vibration test standards in the automotive industry. Many automotive companies have their own specifications and product testing procedures.