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This paper describes the joint development by Tenneco and Pi Shurlok of a complete diesel engine aftertreatment system for controlling particulate matter emissions. The system consists of a DOC, DPF, sensors, controller and an exhaust fuel injection system to allow active DPF regeneration. The mechanical components were designed for flow uniformity, low backpressure and component durability. The overall package is intended as a complete PM control system solution for OEMs, which does not require any significant additions to the OEM's engine control strategies and minimizes integration complexity. Thus, to make it easier to adapt to different engine platforms, ranging from small off-road vehicle engines to large locomotive engines, model-based control algorithms were developed in preference to map-based controls.

The future of diesel-engine-powered passenger cars and light-duty vehicles in the United States depends on their ability to meet Federal Tier 2 and California LEV2 tailpipe emission standards. The experimental purpose of this work was to examine the potential role of fuels; specifically, to determine the sensitivity of engine-out NOx and particulate matter (PM) to gross changes in fuel formulation. The fuels studied were a market-average California baseline fuel and three advanced low sulfur fuels (<2 ppm). The advanced fuels were a low-sulfur-highly-hydrocracked diesel (LSHC), a neat (100%) Fischer-Tropsch (FT100) and 15% DMM (dimethoxy methane) blended into LSHC (DMM15). The fuels were tested on modern, turbocharged, common-rail, direct-injection diesel engines at DaimlerChrysler, Ford and General Motors. The engines were tested at five speed/load conditions with injection timing set to minimize fuel consumption.

This paper reports on Ford's participation in the PNGV ‘Ad Hoc’ Diesel Fuel Test program - Phase I. The purpose of this program was to assess the potential benefits of various fuel properties aimed at reducing engine-out emissions of NOx and particulates to meet LEV2 and Tier 2 emission standards. Four alternative fuels were evaluated using a Ford 1.2L DIATA diesel engine: 1) California Certification fuel (CARB), 2) low sulfur hydro-cracked fuel (LSHC), 3) LSHC fuel with a 15% Dimethoxy Methane blend (DMM), and 4) neat Fischer-Tropsch (FT100) fuel. Design of Experiments (DOE) and conventional techniques were used to evaluate the fuels at five speed and load conditions. Exhaust gas recirculation (EGR), injection rail pressure, and beginning of injection (BOI) timing were controlled during the tests. Steady-state engine performance, emissions, and cylinder pressure (combustion) data were recorded for each fuel.

Work by Plee, Ahmad, and coworkers in the 1980s [1, 2, 3, 4 and 5] showed that for changes in intake air state, Diesel NOx, soot, soluble organic fraction, and HC emissions could be correlated using the stoichiometric flame temperature calculated at SOC or peak pressure conditions. In the present work, similar flame temperature correlations are obtained for emissions from three test engines; a 1.2L high speed direct injection (HSDI) Diesel, a 2.4L HSDI Diesel, and a 2.34 L single cylinder direct injection (DI) Diesel engine, the first of which was tested using four alternative fuels. Use of the flame temperature correlations presented may reduce the number of engine tests required to evaluate the effects of EGR on emissions of NOx, particulate, and HC, even when alternative fuels are used.

EPA 2015 Tier IV emission requirements pose significant challenges to large diesel engine after treatment system development with respect to reducing exhaust emissions including HC, CO, NOx and Particulate Matter (PM). For a typical locomotive, marine or stationary generator engine with 8 to 20 cylinders and 2500 to 4500 BHP, the PM reduction target could be over 90% and NOx reduction target over 75% for a wide range of running conditions. Generally, HC, CO and PM reductions can be achieved by combining DOC, cDPF and active regeneration systems. NOx reduction can be achieved by injecting urea as an active reagent into the exhaust stream to allow NOx to react with ammonia per SCR catalysts, as the mainstream approach for on-highway truck applications.

The introduction of stringent EPA 2015 regulations for locomotive / marine engines and IMO 2016 Tier III marine engines initiates the need to develop large diesel engine aftertreatment systems to drastically reduce emissions such as SOx, PM, NOx, unburned HC and CO. In essence, the aftertreatment systems must satisfy a comprehensive set of performance criteria with respect to back pressure, emission reduction efficiency, mixing, urea deposits, packaging, durability, cost and others. Given multiple development objectives, a systematic approach must be adopted with top-down structure that addresses top-level technical directions, mid-level subsystem layouts, and bottom-level component designs and implementations. This paper sets the objective to provide an overview of system development philosophy, and at the same time touch specific development scenarios as illustrations.