Car Engine Road Spectrum Load Mapping Synthesis Preliminary Study

The level of fatigue reliability is one of the most important performances to the quality of products of vehicle and power machine. Fatigue destroy is a complex problem. Many elements can affect the fatigue intensity. People in practice discover that we can use working stress-time course to build the standard load spectrum about a machine through the load sampling. Using the S-N curve and the standard load spectrum, we can calculate the fatigue damages about the machine when working for some time.This paper is a part of research on the main fatigue durability in the engine. It is the first time we use mapping combine method about the fatigue durability in the engine, so this experiment is a primary trial validate. On the base of mapping combine method about the trial flow in the load spectrum, We use Genetic Algorithms toolbox in the Matlab to build up the mapping space parameters. Through the Genetic Algorithms, We construct the output torque about the engine. When the mapping is over, It gives a introduction about the RS theory. Taking use of RS theory, We calculate the output torque through the measurement of the engine's rotate speed. Then we get a compare. In the example, We figure out the pressure in the inlet engine combining with other parameters. It gets the 3 dimension crankshaft model in the UG according to the part size parameters. When putting the crankshaft as a flexible body, We use the ANSYS to get the finite element analysis. Multi rigid body dynamics model is built by software MSC.adams, and put the pressure to the Multi body. It can get the torsional vibration response curve and get a compare with the practical curve.It is concluded that there are some differences with the practical data. From the compare with the RS result and the practical example. There are some theory innovation and practical meaning to use the mapping combine method in the engine .