Engine Combustion and Pressure Development - Effects of Mixture Ratio, Spark Position, and Throttle Opening on Flame Pictures and Pressure Cards

HIGH-SPEED motion pictures of the flames in a gasoline engine have been photographed, together with pressure records of the same explosions. These records of flame motion and pressure development have been examined to determine the effects of changing the mixture ratio, the spark position, and the throttle opening.

Also, some quantitative relationships between the fraction of charge burned and the pressure developed at any time during the explosion have been tested with the experimental data observed while operating the engine under several sets of conditions.

It is shown that, by means of these relationships, both the fractional volume and fractional mass of charge inflamed at any time may be calculated from the pressure cards with an accuracy comparable with the accuracy of the present experimental observations.