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The Automotive Market in the United States is moving in the direction of more Light Trucks and fewer Small Cars. The customers for these vehicles have not changed, only their purchase decisions. Cummins has studied the requirements of this emerging market. Design and development of an engine system that will meet these customer needs has started. The engine system is a difficult one, since the combined requirements of a very fuel-efficient commercial diesel, and the performance and sociability requirements of a gasoline engine are needed. Results of early testing are presented which show that the diesel is possibly a good solution.

Design and development of the Cummins Signature 600, a new high horsepower dual overhead cam truck diesel engine, has been completed. The Signature 600 product system includes an all-new engine, controls, fuel system, and business information systems. During product definition, particular emphasis was placed on target markets, customer input to design, engineering and manufacturing processes, concurrent engineering and extensive mechanical and thermal analyses. Cummins Signature 600 fulfills the needs of Owner-Operator and Premium Fleet linehaul trucking businesses.

Cavitation corrosion is a very complex phenomenon that is governed by a formidable amount of factors and parameters. The phenomenon is a multi-disciplinary one which involves several aspects of physical sciences and engineering. This process is a slow progressive phenomenon with its detrimental effects being felt after severe damage has already occurred. A real time detection method for the severity of fluid cavitation and bubble collapse is described. The results are correlated to dynamic instantaneous pressure fluctuation measurements. The method is fast, reliable, and less restrictive of the sensing location. It has been tested and verified through a specially designed cavitation test rig and instrumentation setup. The method can be used for cavitation studies on ultrasonic bench rig tests and for cavitation measurements on running engines. The method was used to shed some light on characteristic cavitation differences between water and glycol which is used in engine coolants.

Diesel engine manufacturers have traditionally done most engine noise development work under steady: state operating conditions. However, truck driveby noise tests are acceleration tests, and engines exhibit different noise behavior under accelerating conditions. Acceleration noise can be affected by engine performance parameters which may have no influence on steady state noise levels. In this study, a test cell simulation of the truck driveby procedure has been developed and evaluated. Test cell simulation and truck driveby results are compared for a naturally-aspirated and a turbocharged engine. This simulation procedure has been shown to predict reliably results measured in vehicles. As a result, the simulation can be used to evaluate engine modifications during the development process without requiring a vehicle installation.

The development of smoke measurement procedures and instruments has been one of the significant factors contributing to the reduction of smoke from diesel-powered trucks. There is a need, however, for better information on the relation between measurements and the appearance of the smoke plume, for improved smokemeters, and for common international test procedures. Studies of smoke plumes using jet theory, alumina tracer, and hydraulic analog techniques indicate that the plumes are sometimes unstable and subject to large-scale shedding in the region where free-plume smokemeters are located. This introduces a significant random variation into smoke measurements made in this location. A future test procedure based on smoke measurements made with a long path (500 mm) in-line smokemeter during a dynamic cycle is suggested for consideration. Smoke limits would be based on tests similar to those conducted by MIRA to relate smoke levels and engine size to human response.

Water was inducted with the intake air and injected emulsified with the fuel, in a conventional single cylinder D.I. diesel engine. The major effects of inducted water were an increase in ignition delay, and reduction in the oxides of nitrogen and smoke at a constant fuel/air ratio. When the water was emulsified with the fuel, the ignition delay increased so much that no benefits were obtained except for a reduction in smoke. The results are compared to a similar study on an engine with the “M” combustion system. The major differences between the results obtained with the two combustion systems are attributed to the differences in the ignition delay caused by the water addition.

Until recently, dry cargo has been unloaded from trucks by use of compressed air. By making the automotive engine act partly as an air compressor during the unloading operation, the auxiliary air compressor mounted on the tractor frame can be eliminated. This paper, in describing the dual diesel, discusses operating characteristics, cycle analysis, and operational problems.