A practical method to determine conveniently the effective cylinder charge in an internal combustion engine through a continuous exhaust gas analysis is described. For gasoline engines, the oxygen content of the exhaust gas is monitored and for diesel engines, n-butane is used as a tracer gas. The method can be used on 2-stroke and 4-stroke cycle engines.
The theoretical basis of the method is discussed and the limits of the application are shown. Actual test results obtained with test engines, which were especially prepared for zero scavenging and for controlled scavenging with air only or with an air/fuel mixture, are quoted.