How Modern Engine Oils can impact on Emission Reduction 2003-01-1989
Automotive engine oils have, for many years, relied on ZnDTP to provide protection against wear. ZnDTP functions by creating a sacrificial chemical layer between contacting metal surfaces which are in relative motion with each other.
In order to meet the requirements of ever more stringent emissions control legislation modern automotive vehicles are now fitted with complex exhaust after treatment devices and engine control systems.
The phosphorous contribution from ZnDTP is, typically, 1000 - 1400 ppm. It has been suggested that phosphorous can have detrimental effect on the performance of the after treatment exhaust catalyst and emission control systems (1,3).
This study demonstrates the effects of reducing phosphorous in automotive engine oils on both exhaust after treatment devices and on emission control system sensors by comparing the performance of two lubricant formulations, differing only in the antiwear chemistry, in fired engine bench tests. This comparison demonstrates that significant improvements in emissions control can be achieved by reducing the level of phosphorous in engine oil formulations without compromising wear protection.