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The study was aimed at assessing the impact of fuel quality on the PN10 and PN23 emissions. A total of 6 fuels having different level of ethanol, renewable components, additives, and aromatic hydrocarbons were tested on the test vehicle. In the first phase of the study, the emission tests were conducted removing the GPF present in the original aftertreatment system to measure the direct impact of different fuels on the tailpipe particle emissions. The emission results showed that heavy aromatics components lead to a significant increase in particle emissions while the fuel with renewable components and E20 emit less PN comparing to the E10 reference fuel. However, those fuel impacts became very small with a GPF present due to a high filtration efficiency independent of fuel type.

This summary covers representative developments from 2008 in diesel regulations, engine technology, and NOx, particulate matter (PM), and hydrocarbon (HC) control. Europe is finalizing the Euro VI heavy-duty (HD) regulations for 2013 with the intent of technologically harmonizing with the US. A new particle number standard will be adopted. California is considering tightening the light-duty fleet average to US Tier 2 Bin 2 levels, and CO2 mandates are emerging in Europe for LD, and in the US for all vehicles. LD engine technology is focused on downsizing to deliver lower CO2 emissions, enabled by advances in boost and EGR (exhaust gas recirculation). Emerging concepts are shown for attaining Bin 2 emission levels. HD engines will make deNOx systems optional for even the tightest NOx standards, but deNOx systems enable much lower fuel consumption levels and will likely be used. NOx control is centered on SCR (selective catalytic reduction) for diverse applications.

This paper will review the field of diesel emission control with the intent of highlighting representative studies that illustrate the state-of-the-art. First, the author reviews general technology approaches for heavy and light duty applications. Given the emerging significance of ultrafines to health, and to emission control technologies, an overview of the significant developments in ultrafine particulate science is provided, followed by an assessment of filter technology. Regarding NOx control, SCR (selective catalytic reduction) and LNT (lean NOx traps) progress is described. Finally, system integration examples are provided. In general, progress is impressive and studies demonstrate that high-efficiency systems are within reach in all highway vehicle sectors. Engines are making impressive gains, and will increase the options for emission control.

The diesel oxidation catalyst is required to remove hydrocarbons and carbon monoxide from the diesel engine exhaust stream while minimizing the impact of all other features such as cost, space, pressure drop, weight, fuel consumption, etc. The challenge of designing a catalytic converter for a particular application then becomes to: first, understand the emissions and other performance targets and requirements for the engine; second, understand the influence each of the converter parameters has on the overall system performance and; third, optimize the system using these relationships. This paper will explore some of the considerations with respect to the second of the above challenges.

To meet tightening emissions standards, alternate pollution abatement technologies are necessary, such as an In-Line Adsorber (ILA) system. The ILA has a first catalyst, an adsorber, and a second catalyst. A diverter directs exhaust gas through the adsorber to capture unconverted hydrocarbons until the first catalyst reaches light-off temperature. The ILA system was designed so that the second catalyst becomes active concurrent with the adsorber hydrocarbon desorption. The system was evaluated using the FTP test with two different secondary air strategies on 3.8 liter V6 and 4.0 liter V8 vehicles. The ILA system performance consistently reduced ∼50-60% of cold start hydrocarbon emissions. This study examined a simplified ILA system designed to operate with a commercial secondary air pump powered by the engine.