Challenges for Future Heavy Duty Diesel Lubricant Development: PC-10/DX-2/Euro IV

Over the last decade, the introduction of increasingly stringent emissions legislation to control emissions from vehicles, has necessitated a variety of changes in Heavy Duty Diesel (HDD) engines to ensure that these requirements can be achieved. These include: the use of increased retardation of fuel injection timing, modifications to fuel injection technology in terms of pressure of injection together with electronic control, the use of inter-coolers and most recently exhaust gas re-circulation (EGR).

It appears clear that US Federal Tier III, Euro IV and Japanese New Long Term (NLT) emissions legislation will result in the widespread use of aftertreatment devices for the reduction of oxides of nitrogen (NOx) and particulate matter (PM) in heavy duty diesel engines. Feedback from vehicle manufacturers (OEMs) indicates that the use of such devices will require the introduction of lubricants with reduced phosphorus, sulfur and ash content to facilitate durability of these aftertreatment devices. This paper will describe the challenges faced in the development of such lubricants and data presented to demonstrate that satisfactory performance may be achieved in terms of wear and corrosion parameters. Data will be presented from Mack T10 and GM 6.5 Roller Follower Wear testing at reduced phosphorus, sulfur and ash levels and the impact of fuel sulfur level investigated. Data will also be presented from the XUD11 BTE test to examine the impact of fuel sulfur level on dispersancy performance. Testing will be required to validate these observations in future engine designs.