THE EFFECTS OF LUBRICATING OIL CONSUMPTION ON THE DETAILED CHARACTERISTICS OF DIESEL PARTICULATE MATTER

Abstract

Testing was carried out on a Cummins N14 single-cylinder heavy-duty D.I. diesel research engine with a full dilution tunnel system to quantify lubricating oil consumption (LOC) rates and determine any effects of changes in LOC rates on the particulate matter. Varying oil consumption rates and their effect on particulates were analyzed at selected operation conditions of the CARB 8-mode test cycle. The three steady-state engine operating conditions tested were mode 4 (1200RPM, 25% load), mode 5 (1200RPM, 100% load), and mode 1 (1800RPM, 100% load). Several engine alterations, consistent with the literature, for changing LOC rates were applied. The alterations consisted of installing an oil control ring with a unit pressure 50% less than the standard value, removing the intake valve stem seals (VSS), removing the exhaust VSS, and removing all (intake and exhaust) VSS. Each of these alterations was tested individually to avoid causing interacting effects. LOC rates were successfully quantified by measuring the calcium concentration in the exhaust particulates. For the engine operating conditions tested, no major differences in detailed PM characteristics for changes in LOC rates were found except for organic carbon emissions at mode 5. In addition, very small changes in the particle size distribution for the lower unit pressure oil control ring were observed for modes 5 and 1 in the size range of 150 to 250 nanometers.