Fuel Consumption
The diagram indicates
that the fuel consumption of an IC engine at constant RPM is dependent
on the Air/Fuel ratio and the Ignition Timing.
The graph shows that
advancing the spark for this engine by 40 degrees (i.e. 40o BTDC) and using
an air/fuel ratio of about 1.4 gives the minimum fuel consumption.
Fuel Consumption as a function of SparkTiming and Air/Fuel ratio, l.