Some aspects of validation of the fuel consumption measurement method

Currently produced diesel engines of different manufacturers, used for the same applications, have comparable specific fuel consumption. Therefore, the laboratories measuring fuel consumption, especially in comparative tests, require the use of more accurate methods of measurement. The Environmental Protection Centre of Motor Transport Institute has recently implemented the fuel consumption measurement method using KMA Mobile flow meter produced by AVL company. This device allows to carry out measurements by both volumetric and mass method, thanks to builtin device for measuring the fuel density. Due to some customers requirements the laboratory began with preparations for obtaining accreditation of the Polish Centre of Accreditation for the procedure of measuring fuel consumption by volumetric and mass method. One of the requirements of the Polish Centre for Accreditation is carrying out the validation of the new method. It can be done by comparing the results obtained with new method with the results of the method already validated. The validated method is described in the regulation. This is the carbon balance method described in UN-ECE Regulations No. 101. The calculation of fuel consumption according to this method is based on a measurement of pollutants emissions of carbon dioxide (CO2), carbon monoxide (CO) and hydrocarbons (THC). This paper describes the fuel consumptions measuring procedure using two methods: mass method using a AVL KMA Mobile flow meter and carbon balance method using the AVL AMA i60 analyzers. To verify measurement results additionally there was fuel consumption measured with using a scale, as a difference of the external fuel tank mass change, from which the vehicle was fuelled during the tests