Devices for use in control of exhaust emissions have become indispensable to motorcycles. In order to evaluate quantitatively the effect of each device, the modal analysis system has to be required.
The Modal Analysis System is one that classifies any driving schedule which is used for emissions measurement into four modes: idle, acceleration, cruise, and deceleration; then measures the emissions continuously using a mini-computer which accumulates the results of the analysis by mode.
Instead of CO2 tracer method, we introduced the method of diluted exhaust gas measurement.
In order for the system to produce reliable measurements, the accuracy of the total installation must be ensured.
This paper describes the improvements of accuracy of analysers, technique on handling delay time and the verifications on the modal analysis system.