Development Of An Ignition Tuning System For Single-cylinder Engine

To find an easy way to measure the load of a single-cylinder engine, the author brings out a new method, which uses the fluctuation ratio of the transient speed in token of the load.Through the force analysis of the piston and the crankshaft, the paper demonstrates that the transient speed is dependent on the force on the crankshaft. The author takes a lot of experiments, which proves that the fluctuation ratio of the transient speed is dependent upon the load of the engine, and the relationship between them is nearly linear, the larger the load is, the bigger the fluctuation ratio is.Based on the linear relationship between the transient speed ratio and the load of the single-cylinder engine, the author developed a ignition tuning system for the single-cylinder engine. The equipment is mainly composed of an analog circuit module, an ECU and a man machine interface. The ECU is composed of 2 ATMEL89C52 single chips, which collaborate together and accomplish measuring and calculating. The ECU can measure the average speed and the fluctuation ratio of the transient speed, and then quickly find a best ignition advance angle in any working condition for the spark ignition engine. The LCD displays the working state of the engine.The author uses the equipment and a dynamometer to calibrate the ignition characteristic map of the single-cylinder engine, and the map is confirmed comparatively accurate: the higher the average speed is, the bigger the ignition advance angle is, and the bigger the fluctuation ratio of the transient speed is, the bigger the ignition advance angle is. It proved that the way using the fluctuation ratio of the transient speed to measure the load in a single-cylinder engine is right and feasible.