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A dilute spark-ignited engine concept has been developed as a potential low cost competitor to diesel engines by Southwest Research Institute (SwRI), with a goal of diesel-like efficiency and torque for light- and medium-duty applications and low-cost aftertreatment. The targeted aftertreatment method is a traditional three-way catalyst, which offers both an efficiency and cost advantage over typical diesel aftertreatment systems. High levels of exhaust gas recirculation (EGR) have been realized using advanced ignition systems and improved combustion, with significant improvements in emissions, efficiency, and torque resulting from using high levels of EGR. The primary motivation for this work was to understand the impact high levels of EGR would have on particulate matter (PM) formation in a port fuel injected (PFI) engine. While there are no proposed regulations for PFI engine PM levels, the potential exists for future regulations, both on a size and mass basis.

A novel urea evaporation and mixing device has been developed to improve the overall performance of a urea-SCR system. The device was tested with a MY2007 Cummins ISB 6.7L diesel engine equipped with an SCR aftertreatment system. Test results show that the device effectively improved the overall NO conversion efficiency of the SCR catalyst over both steady-state and transient engine operating conditions, while NH₃ slip from the catalyst decreased.

The VanDyne SuperTurbocharger (SuperTurbo) is a turbocharger with an integral Continuously Variable Transmission (CVT). By changing the gear ratio of the CVT, the SuperTurbo is able to either pull power from the crankshaft to provide a supercharging function, or to function as a turbo-compounder, where energy is taken from the turbine and given to the crankshaft. The SuperTurbo's supercharger function enhances the transient response of a downsized and turbocharged engine, and the turbo-compounding function offers the opportunity to extract the available exhaust energy from the turbine rather than opening a waste gate. Using 1-D simulation, it was shown that a 2.0-liter L4 could exceed the torque curve of a 3.2L V6 using a SuperTurbo, and meet the torque curve of a 4.2-liter V8 with a SuperTurbo and a fresh-air bypass configuration. In each case, the part-load efficiency while using the SuperTurbo was better than the baseline engine.

The classical approach to prepare engine exhaust emissions control systems for evaluation and certification is to condition the fresh parts by aging the systems on an engine/dynamometer aging stand. For diesel systems this can be a very lengthy process since the estimated service life of the emissions control systems can be several hundred thousand miles. Thus full useful life aging can take thousands of engine bench aging hours, even at elevated temperatures, making aging a considerable cost and time investment. Compared to gasoline engines, diesel engines operate with very low exhaust gas temperatures. One of the major sources of catalyst deactivation is exposure to high temperature [ 1 ].

The US EPA emission standards for 2010 on-highway and 2014 non-road diesel engines are extremely stringent, both in terms of oxides of nitrogen (NOX) and particulate matter (PM). Diesel engines typically operate lean and use at least 40-50 percent more air than what is needed for stoichiometric combustion of the fuel. As a result, significant excess oxygen (O₂) is present in diesel exhaust gas which prevents the application of the mature three-way catalyst (TWC) technology for NOX control used in gasoline engines. The objective of this work was to investigate whether or not the catalyzed DPF had a TWC-type of effect on NOX emissions and if so, why and to what extent when used on a diesel engine operating at reduced A/F ratio conditions.

Particulate Matter (PM) emissions from gasoline direct injection (GDI) engines are becoming a concern and will be limited by future emissions regulations, such as the upcoming Euro 6 legislation. Therefore, PM control from a GDI engine will be required in addition to effective reduction of HC, CO and NOx emissions. Three different integrated aftertreatment systems were developed to simultaneously reduce PM, HC, CO and NOx emissions from a preproduction Ford 3.5L EcoBoost GTDI engine, with PM reduction as the major focus. PM reduction efficiencies were calculated based on the measurements of PM mass and solid particle number. Test results show that tradeoffs exist in the design of aftertreatment systems to significantly reduce PM emissions from a GDI engine.

This paper summarizes the validation testing of the Horiba Instruments OBS-2200 gaseous portable emissions measurement system (PEMS) for in-use compliance testing per Title 40 of the Code of Federal Regulations (CFR) Part 1065.920 (Section 1065.920). The qualification process included analyzer verifications as well as engine testing on a model-year 2007 heavy-duty diesel engine produced by Volvo Powertrain. The measurements of brake-specific emissions with the OBS-2200 were compared to those of a CFR Part 1065-compliant CVS test cell over a series of not-to-exceed (NTE) events. The OBS-2200 passed all linearity verifications and analyzer checks required of PEMS. Engine test validation was achieved for all three regulated gaseous emissions (CO, NMHC, and NOX) per 40 CFR Part 1065.920(b)(5)(i), which requires a minimum of 91 percent of the measurement allowance adjusted deltas to be less than or equal to zero.

Southwest Research Institute, as part of the Clean Diesel IV consortium, built a multi-cylinder HCCI engine that ran in the HCCI combustion mode full-time. The engine was used to develop HCCI fuels, demonstrate the potential operating range of HCCI, and to demonstrate the feasibility of transient control of HCCI. As part of the engine design, a hardware based method of decoupling control of air and EGR was developed and patented [ 1 ]. The system utilized a positive displacement supercharger with a controlled bypass valve for air-flow control, and a high-pressure loop EGR system with variable geometry turbocharger to control the EGR rate. By utilizing the system, the required precision from the air and EGR control in the engine controller was reduced.

In recent years, Diesel Particulate Filter (DPF) systems have become the state-of-the-art technology to realize low particulate emission for light, medium or heavy-duty diesel vehicles. In addition to good filtration efficiency and thermo-mechanical robustness, the engine backpressure resulted from the DPF installation is an important parameter which directly impacts the fuel economy of the engine. The goal of this experimental test series was to determine the dependence of fuel consumption on engine backpressure resulted from a DPF installed on a heavy-duty application. The testing was executed on a MY2003 Volvo D12 heavy-duty diesel engine in an engine test cell at Southwest Research Institute (SwRI). Empty DPF cans were used with an exhaust valve to mimic the post turbo pressure levels for two different types of DPF materials at nine selected engine operating points of the European Stationary Cycle (ESC).