A study on the prediction of gas consumption of CNG buses

To estimate the practical gas consumption levels of in-use CNG buses in Beijing, the sampling exhaust emissions of in-use CNG buses in practical operation are measured using a portable emissions measurement system. And then based on these emission data, instantaneous gas consumption rates of these buses are calculated with carbon balance method, and the feature of CNG bus gas consumption are analyzed. The gas consumption rate database for these buses is set up according to the classification by speed, acceleration and vehicle specific power (VSP), and a model for gas consumption of CNG buses in practical operation is created. Verifications show that the gas consumption calculated with the model is in good agreement with the real gas consumptions measured with a discrepancy within 10%. Thus once the operation data of vehicles in certain category are obtained by using global positioning system, the gas consumption of vehicle in the same category can well be predicted based on the model.