DESIGNING THE WORLDS LARGEST INJECTION MOLDED NYLON PART, A COWLING ASSEMBLY FOR A MERCURY MARINE LARGE FOUR-STROKE OUTBOARD ENGINE

摘要

The cowling (engine cover assembly) for a marinernoutboard engine serves several critical functions. Itrnprotects the engine from the environment andrnprovides structural protection to the under-cowlrncomponents. The cowling routes air into the enginernwith minimal power loss, and at the same timernprevents water from entering the enginerncompartment. The cowl assembly dampens enginernnoise and vibration thus providing improved NVHrn(Noise Vibration and Harshness) characteristics.rnThe cowl assumes the form of styled surfaces tornmake the engine aesthetically pleasing. In addition,rna well designed latching system ensures that therncowling stays on the engine, and providesrnstructural protection to internal components in thernevent of the boat striking submerged objects suchrnas floating logs or rocks.rnThese requirements of an outboard engine cowlingrndemand special considerations in design, materialrnselection, and manufacturing. The top cowl is thernworlds largest structural and cosmetic glassrnreinforced nylon part, the development of whichrnwas very challenging. The key aspects of arnpatented, innovative, low cost cowling assemblyrnfor a large four-stroke outboard engine, itsrnadvantages and benefits are presented in this paper.