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Exhaust emissions from heavy-duty truck and bus diesel engines have been legislated from 1970 to 2010. Smoke emissions continue to be controlled but exhaust odor regulations were never promulgated. Gaseous emissions (oxides of nitrogen, carbon monoxide and hydrocarbons) were regulated in 1973 and particulate matter first regulated in 1988. Throughout this period there has been cooperation, lawsuits, statement of principles, Consent Decrees and now The Clean Diesel Independent Review Panel. If the 2010 rulemaking remains in place, diesel emissions of NOx and PM will have been reduced 99% from uncontrolled levels.

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 use of small-hole diesel injector tips and high injection pressures was investigated as a countermeasure to the increased particulate matter (PM) emissions formed when using exhaust gas recirculation (EGR) in diesel engines. This study examined the use of injector tip hole sizes down to about 0.09-mm (0.0035 in.), and injection pressures to 300 MPa (3000 bar, or 43,500 psi). The first phase of these studies was conducted in a high-temperature, high-pressure combustion bomb, with supporting calculations using a unit injector model, a jet-mixing model, and a diesel jet evaporation model. The second phase was conducted in a commercial diesel engine of 12.7-liter displacement designed to meet U.S. 1998 emissions levels. Engine tests were conducted with a baseline cam and a faster rise-rate cam, and three different hole tip sizes. The cams consisted of a baseline cam and a cam of similar design, but with a 12 percent faster rise rate.

The Detroit Diesel Corporation (DDC) DELTA engine has been specifically designed for the North American market. The advanced engine technologies being pursued for this engine enables its applications to the light truck/SUV vehicles for personal transportation as well as for the light commercial use, such as urban delivery vans. This paper reports on the progress attained so far in engine development. The next stage is currently under way resulting in Generation 1.0 DELTA engine technology. The results of various technology assessments on Generation 0.X hardware are reported. Further, the Generation 1.0 design and its potential will be briefly presented. It is concluded that the DELTA engine technology, including breakthrough advancements, is viable for practical applications to meet future light-duty and heavy-duty emissions with potentially attractive commercial features.

This paper studies the effect of nozzle geometry on the flow characteristics inside a diesel fuel injection nozzle and correlates to the subsequent atomization process under different operating conditions, using simple turbulent breakup model. Two kinds of nozzles, valve covered orifice (VCO) and mini-SAC nozzle, with various nozzle design parameters were studied. The internal flow inside the nozzle was simulated using 3-D computational fluid dynamics software with k-ε turbulence model. The flow field at the nozzle exit was characterized by two parameters: the fuel discharge coefficient Cd and the initial amplitude parameter amp0. The latter parameter represents the turbulence characteristics of the exit flow. The effects of nozzle geometry on the mean velocity and turbulent energy distribution of the exit flow were also studied. The characteristics of the exit flow were then incorporated into the spray model in KIVA-II to study the effect of nozzle design on diesel spray behavior.

This paper was written to document the results of a development program conducted by Detroit Diesel Corporation in cooperation with U.S. Army. The purpose of this program, was to apply “state-of-the-art” low heat rejection (LHR) technology and cold starting improvements to the 8V-71T engine used in the Self-Propelled Howitzer and Ammunition support vehicles. The principal focus of this report covers the diesel engine air system, Low Heat Rejection cylinder head developments, and the resultant synergism impacting reduced cooling system burden, improved engine performance, reliability, durability, fuel economy, and smoke signature. Concurrent development of a glow plug system is integrated to this development with dramatic resultant impact on engine startability and tactical vehicle performance.

The extensive reliability engineering program performed during the development of the DDEC I and DDEC II systems is described. This program insured that established reliability goals would be met and objectively demonstrated before the DDEC systems were released to the marketplace. Reliability goals representing the most stringent customer expectations were established at the program start. Then a formal reliability growth test program was performed that included running on engine dynamometers, at selected domiciled truck locations and in a broad range of customer revenue service vehicles.