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Six laboratories capable of chassis-testing heavy-duty vehicles participated in a crosscheck program designed to compare emissions results from a Ford L-9000. The single-axle vehicle was shipped to each laboratory and tested through a series of UDDS and steady-state cycles. The resulting data were compared statistically using reproducibility and repeatability analyses. Although one lab produced some results that significantly differed from the other five, the remaining labs produced comparable results. TPM, CO and THC were the most variable while NOX and CO2 were most stable. Lab differences included atmospheric and environmental conditions, road-load curve application and drivers. Comparison of steady state and transient tests suggest that driver variability is not a major factor.

This paper explores the feasibility of using in-cylinder pressure-based variables to predict gaseous exhaust emissions levels from a Navistar T444 direct injection diesel engine through the use of neural networks. The networks were trained using in-cylinder pressure derived variables generated at steady state conditions over a wide speed and load test matrix. The networks were then validated on previously “unseen” real-time data obtained from the Federal Test Procedure cycle through the use of a high speed digital signal processor data acquisition system. Once fully trained, the DSP-based system developed in this work allows the real-time prediction of NOX and CO2 emissions from this engine on a cycle-by-cycle basis without requiring emissions measurement.

In this last decade, non-destructive X-ray measurement techniques have provided unique insights into the internal surface and flow characteristics of automotive injectors. This has in turn contributed to enhancing the accuracy of Computational Fluid Dynamics (CFD) models of these critical injection system components. By employing realistic injector geometries in CFD simulations, designers and modelers have identified ways to modify the injectors’ design to improve their performance. In recent work, the authors investigated the occurrence of cavitation in a heavy-duty multi-hole diesel injector operating with a high-volatility gasoline-like fuel for gasoline compression ignition applications. They proposed a comprehensive numerical study in which the original diesel injector design would be modified with the goal of suppressing the in-nozzle cavitation that occurs when gasoline fuels are used.