DESIGN OF IGNITION AND FUEL SYSTEMS FOR 2-STROKE ENGINES - A STATISTICAL EXPERIMENTAL-DESIGN APPROACH

Two problems in the production of two-stroke outboard marine engines, namely the low speed problem at wide open throttle and the pickup stal l problem, are solved using a statistical experimental design approach . Because theoretical relationships between the controllable variables and the performance of the engine are difficult to establish, it is u nrealistic to solve these problems analytically from a thermodynamic a pproach. Experimental design has been proved to be an effective and ef ficient methodology for solving the problems in this situation. In thi s project, four experiments were conducted sequentially, and more than 200 readings were taken. It is required to optimize the setting of th e different parameters so that the engine can reach a sufficiently hig h speed at wide open throttle and the vibration is reduced to an accep tably low level. Analysis of the experimental results suggests optimal choices of spark plug, advance firing angle, pressure relief hole siz e, spark plug gap, fuel flow rate, and rate of change of fuel flow rat e.