Cold Operability of Light Duty Diesel Vehicles - Importance of Vehicle Testing

It is widely known that different factors, such as cold properties of a fuel as well as a vehicle design, affect the cold operability limit of vehicles. In this study, the aim was to get a better understanding of the properties of modern Light Duty Diesel (LDD) vehicles (2014-2020) that define their cold operability temperature limit. Moreover, the aim was to find out what a responsible fuel producer can do, in addition to providing a proper fuel that meets the specification, to ensure that a vehicle stays operable at cold temperatures. Similar study was done 10 years ago by Neste with the LDD vehicles of that time [1]. Therefore there was a need to update the info to concern the modern LDD vehicles. In this study the operability limit difference between the worst and the best operating LDD vehicle was >10°C (nbr of LDD vehicles = 5) with the same fuel. The limits were determined in a cold chamber using a chassis dynamometer. This operability variance indicates a significant effect of vehicle design on the vehicle’s cold operability limit. The results showed no correlation between diesel fuel’s cold filter plugging point (CFPP) or the surface area of the fuel filter and vehicle cold operability. Therefore, fuel producers should continue the fuel testing using real vehicles to ensure that the produced fuels are suitable for the specific conditions. Moreover, it is good to keep in mind that the results of this study, which demonstrated significant differences in LDD vehicles’ cold operability, were obtained using only one fuel having a specific CFPP, so further studies on this topic are needed.