Cyclic Variations and Average Burning Rates in a S. I. Engine

A method of calculating mass burning rates for a single cylinder spark-ignition combustion engine based on experimentally obtained pressure-time diagrams was used to analyze the effects of fuel-air ratio, engine speed, spark timing, load, and cyclic cylinder pressure variations on mass burning rates and engine output.

A study of the effects on mass burning rates by cyclic pressure changes showed the low pressure cycles were initially slow burning cycles. Although large cyclic cylinder pressure variations existed in the data the cyclic variations in imep were relatively small.