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Technical Paper

Recent DPF/SCR Results Targeting US2007 and Euro 4/5 HD Emissions

Selective Catalytic Reduction (SCR) of Nitrogen Oxide (NOx) emissions using ammonia or a 32.5%-urea solution has been used for many years in a variety of stationary applications. These applications include but are not limited to coal fired power plants, gas turbines, diesel locomotives, marine engines, as well as other stationary diesel and non-diesel engine applications. Global emission limits for mobile heavy-duty diesel engines are becoming increasingly rigid. In response to this trend the diesel industry has begun testing and applying various emission control technologies to mobile applications. SCR is one such technology. Europe is the first major market to introduce SCR into the heavy-duty (class 8) as well as medium-duty (class 4-7) truck applications. The EURO4 standards (effective Oct. 2005/2006) and the EURO5 standard (effective 2008) favor SCR as the NOx reduction technology of choice in the European Union (EU).
Technical Paper

Sooted Diesel Engine Oil Pumpability Studies as the Basis of a New Heavy Duty Diesel Engine Oil Performance Specification

Changing diesel engine emission requirements for 2002 have led many diesel engine manufacturers to incorporate cooled Exhaust Gas Recirculation, EGR, as a means of reducing NOx. This has resulted in higher levels of soot being present in used oils. This paper builds on earlier work with fresh oils and describes a study of the effect of highly sooted oils on the low temperature pumpability in diesel engines. Four experimental diesel engine oils, of varying MRV TP-1 viscosities, were run in a Mack T-8 engine to obtain a soot level ranging between 6.1 and 6.6%. These sooted oils were then run in a Cummins M11 engine installed in a low temperature cell. Times to lubricate critical engine components were measured at temperatures ranging between -10 °C and -25 °C. A clear correlation was established between the MRV TP-1 viscosity of a sooted oil and the time needed to lubricate critical engine components at a given test temperature.
Technical Paper

A New Engine Test for the Development of Heavy Duty Diesel Engine Oils for Engines with Exhaust Gas Recirculation: The Mack T-10 Test

More stringent emission legislation has been a driver for changes in the design of Heavy Duty Diesel engines since the 1980s. Optimization of the combustion processes has lead to significant reductions of exhaust emission levels over the years. However, in the year 2002, diesel engines in the USA will have to meet an even more stringent set of emission requirements. Expectations are that this will force most engine builders to incorporate Exhaust Gas Recirculation (EGR). Several studies of the impact of EGR on lubricant degradation have shown increased levels of contamination with soot particles and acidic components. Both of these could lead to changes in lubricant requirements. The industry is developing a new specification for diesel engine lubricants, PC-9, using test procedures incorporating engines with EGR.
Technical Paper

The Development of Urea-SCR Technology for US Heavy Duty Trucks

Prototype selective catalytic reduction (SCR) systems using urea have been demonstrated on diesel trucks in Europe in recent years. In view of upcoming stringent emissions control standards for US HD diesel engines, urea-SCR is being evaluated by US engine and truck manufacturers. The authors and their companies have worked jointly on a project to develop, test, and demonstrate urea-SCR on a US HD diesel engine and Class-8 truck. A prototype urea-SCR system was applied to a 12-liter HD diesel engine. The engine model selected is rated at 350 bhp and is common for highway trucks. The only engine modifications were changes to the injection timing control map in order to better suit the application of the urea-SCR system. This paper details two demonstration phases of the project as follows. The first phase includes recent emissions cell tests using a new compact SCR catalyst and an engine calibration optimized for lower NOX.
Technical Paper

Case History: Engine Timing Gear Noise Reduction

This paper describes the procedures used to reduce the tonal noise of a class eight truck engine timing gear train that was initially found to be objectionable under idle operating conditions. Initial measurements showed that the objectionable sounds were related to the fundamental gear mesh frequency, and its second and third harmonics. Experimental and computational procedures used to study and trouble-shoot the problem include vibration and sound measurements, transmission error analysis of the gears under light load condition, and a dynamic analysis of the drive system. Detail applications of these techniques are described in this paper.
Technical Paper

Mack Trucks' New E7 Diesel Engine

Mack Trucks' E7 direct injection heavy-duty diesel engine is a four cycle, in-line six cylinder design. The 728 cu in. (12 1) engine is turbocharged and chassis mounted air-to-air aftercooled. The E7 is being introduced in 1989 with power ratings of 250 hp to 400 hp (186 kW to 298 kW) at 1700 to 1800 rpm, calibrated to 1990 EPA standards. Highlights of the E7 engine's design, development and performance are presented. Information is included which illustrates the strategies utilized to attain program goals of controlling weight and cost while extending power ratings, reducing emissions levels, and improving fuel economy, serviceability, durability and reliability.
Technical Paper

Particulate Traps: Some Progress; Some Problems

Two ceramic monolith wall flow diesel particulate traps, incorporating a new split flow design with a base metal catalytic coating were tested on line haul highway trucks to investigate their performance characteristics. The trucks were equipped with a 300 HP turbocharged and after-cooled engine. After-cooler by-pass was used to effect the regeneration of the trap and an elapsed-time scheme was employed to control the regeneration process. Tests were terminated after one trap completed 147,500 miles of operation on the truck for in-depth examination of the trap to determine the cause of substantial increase in back pressure. Tests with the second trap of identical design was also terminated due to filtering efficiency loss, the cause of which was traced to a flaw in the canning arrangement. This arrangement permitted exhaust flow to by-pass the element and led to melt down of the trap, due to reduced flow during regeneration.
Technical Paper

Air Isolation of Class 8 Highway Tractor Cabs

A foundation of highway truck ride and cab suspension historical evolution is laid describing the influence of marketplace demands, highway conditions, and government laws. Ride quality test methods are revealed along with variables tried and conclusions drawn. These data and techniques are then used to design cab suspension systems for a new line of truck products including both conventional and COE cabs.
Technical Paper

Development Of A Laboratory Gear Oil Spalling Test

This paper describes development of a full-scale laboratory truck axle test used to predict the field performance of gear lubricants in heavy truck use. The relationship between laboratory results and known field performance will be described, as will a unique way of analyzing laboratory results. Data will also be presented which will show the laboratory test to be both repeatable and reproducible. Finally, data will be presented which shows lubricant additive type to play a vital role in defining field performance.
Technical Paper

Mack's E9 Series V8 Engines With Chassis Mounted Charge Air Cooling

A new 998 CID V8 engine series has been developed by Mack Trucks, Inc. to supplement its line of heavy duty diesel engines. These engines, the E9 Series, are available in two configurations--a 400 bhp (298 kW) high torque rise version and a 440 bhp (328 kW) conventional torque backup version. Increased horsepower and improved fuel economy were achieved through the development of a chassis mounted charge air cooler and a new four-valve cylinder head. In addition, significant durability improvements were obtained due to the reduced thermal loadings resulting from the lower charge air temperatures. Additional noteworthy features include a new injection pump, improved lube oil system, advanced piston design, and proper selection of seals and gasket materials.
Technical Paper

Flywheel Power Takeoffs - Continuous Power for Truck Mounted Equipment

The truck flywheel power takeoff has proven itself as a reliable means of supplying continuous power to a variety of mounted equipment. The features of available units are described in detail in an effort to provide the design and application engineer with complete information regarding their function and application, and to stimulate expanded usage of this constant power source.