Lubricant Base Oil effects on Regulated EURO II Heavy-duty Diesel Engine Emissions and Fuel Economy

摘要

Increasing environmental concern is leading to the reduction of permissible regulated vehicle exhaust emissions in the major world markets. The data presented in this paper is derived from tests conducted on two, EURO II emission level heavy-duty diesel engines in two different programmes. Test lubricants used in this study consisted of standard mineral, VHVI and synthetic base oils blended in various proportions with performance additives. In each case, lubricants of the same or comparable viscosity class, performance level and other parameters were compared. The major conclusions are: 1. The use of PAO based lubricants can reduce particulate emission mass in the European Transient Cycle (ETC) by between 35 ― 55% relative to standard mineral oil based lubricants. PAO based lubricants gave an average reduction in particulate mass emission of 30% when compared to lubricants based on VHVI oils. 2. The use of PAO based lubricants reduce particulate emission mass in a simulated ECE R-49 13-mode cycle by up to 30% relative to standard mineral oil based lubricants. PAO based lubricants gave an average reduction in particulate mass emission of 13% when compared to lubricants based on VHVI oils. 3. Under transient conditions, PAO based lubricants generate on average 40-50% fewer particulates in the range 36nm-7μm compared to lubricants based on mineral and VHVI oils 4. PAO based lubricants allow the formulation of low viscosity 5W-30 heavy-duty diesel engine oils with fuel economy benefits of up to 2.4% relative to standard 15W-40 mineral oil based lubricants measured over the ETC.