The IEA Advanced Motor Fuels Agreement has initiated this project concerning the application of biodegradable lubricants to diesel and gasoline type vehicles.
Emission measurements on a chassis dynamometer were carried out. The purpose of these measurements was to compare the emissions of CO, CO2, NOx, THC, PM, lubricant-SOF and PAH from one diesel and one gasoline type vehicle using biodegradable lubricants and conventional lubricants. This paper describes the results of the experiments with the diesel type vehicle only. Lubricant consumption and fuel consumption are other important parameters that have been evaluated during the experiments.
Both vehicle types were operated on conventional crude oil based fuels and alternative fuels. The diesel vehicle was operated on conventional diesel fuel from a Danish fuel station, low sulfur diesel from Sweden and biodiesel, which was bought at a fuel station in Germany. The driving patterns that were applied in these experiments were the FTP and EU test cycles.
Since the biodegradability of lubricants changes with age, it was necessary to measure this change by driving the vehicles for a number of kilometers in order to obtain a full picture of the environmental impact of implementing biodegradable lubricants. Therefore lubricant samples were taken from the engine crankcase after driving 7500 km on the road. These samples were analyzed in order to evaluate biodegradability of the used lubricant and engine wear.
The main findings from the study can be summarized as:
the application of a biodegradable lubricant did not result in any unusual wear on the engine
the biodegradability of the aged lubricant was dependent on the applied fuel, biodiesel showing higher biodegradability than conventional diesel
the lubricant consumption with the biodegradable lubricant, compared to the reference lubricant, was dependent on the driving pattern
the lubricant was the main contributor to the soluble organic fraction of the particulates emitted, only biodiesel gave a contribution from the fuel
a slightly higher fuel consumption and NOx emission was noticed with application of biodegradable lubricant compared to conventional lubricant