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As on-highway heavy-duty diesel engine designs have evolved to meet tighter emission regulations, the crankcase environment for heavy-duty engine lubricants has become more challenging. The introduction of Exhaust Gas Recirculation (EGR) has allowed for significant reductions of exhaust emissions, but has led to increased oxidation and acid build-up in the lubricant. Engine lubricant quality is important to help ensure engine durability, engine performance, and reduce maintenance downtime. Increased acidity and oxidation accelerate the rate at which the lubricant quality is degraded and hence shorten its' useful life. This paper explores the use of a lube filter with a controlled additive release to maintain lubricant quality.

In order to meet the U.S. EPA's 2007 on-highway emission standards for particulate and NOx, all diesel engines will require diesel particulate fi lters (DPFs) and cooled exhaust gas recirculation (EGR) and will utilize ultra-low sulfur fuel. As this will be the first time that all on-highway diesel engines will employ DPFs combined with ultra-low-sulfur fuel, the Engine Manufacturers Association (EMA) requested that a new oil category be developed to provide compatibility with DPFs in the exhaust system, as well as engine durability for both new and legacy engines. This paper reviews the development of this new oil category called API CJ-4, which will be introduced in October 2006. This diesel engine oil category is the first in the U.S. which limits the oil's sulfated ash, phosphorus, and sulfur in order to insure adequate service life of the DPF. The API CJ-4 oil category includes 9 fi red engine tests and 6 bench tests.

This oil category was driven by two new cooled exhaust gas recirculation (EGR) engine tests operating with 15% EGR, with used oil soot levels at the end of the test ranging from 6 to 9%. These tests are the Mack T-10 and Cummins M11 EGR, which address ring, cylinder liner, bearing, and valve train wear; filter plugging, and sludge. In addition to these two new EGR tests, there is a Caterpillar single-cylinder test without EGR which measures piston deposits and oil consumption control using an articulated piston. This test is called the Caterpillar 1R and is included in the existing Global DHD-1 specification. In total, the API CI-4 category includes eight fired-engine tests and seven bench tests covering all the engine oil parameters. The new bench tests include a seal compatibility test for fresh oils and a low temperature pumpability test for used oils containing 5% soot. This paper provides a review of the all the tests, matrix results, and limits for this new oil category.

The Cummins M-11/EGR diesel engine test is a key tool in evaluating lubricants for the new PC-9 performance category. Wear on liners, crossheads, rocker arms and top ring faces of M-11/EGR high soot test engines operated with two different test cycles was studied through analytical surface techniques. The first test cycle used in this study was an early prototype PC-9 cycle, and the second test cycle was the PC-9 test procedure. Abrasive wear was observed on liners, crossheads and top ring faces. In addition to abrasive wear, corrosive wear was also found on M-11/EGR liners. However, no corrosive wear was observed on crossheads, rocker arms or top ring faces. Soot provides the major contribution to abrasive wear, since the widths of the relatively uniform parallel grooves in the wear scars closely match the primary soot particle sizes. More importantly, soot produced by the M-11/EGR engine was found to be harder than the engine parts.