The U.S. Environmental Protection Agency (EPA) recently issued a notice of violation against Volkswagen (VW) for installing a defective device in certain models of diesel cars to circumvent emission tests for nitrogen oxides (NOx). We quantified the health and economic impacts of extra NOx emissions attributable to non-compliant vehicles in the U.S. using the EPA's Co-Benefits Risk Assessment m...

To meet Euro VI emission targets for heavy-duty applications, truck manufacturers concentrate on Exhaust Gas Recirculation (EGR) and its combination with urea-based Selective Catalytic Reduction (SCR). TNO developed a concept that opens the route for an alternative solution which relies on SCR as the main technology for NOx abatement. This concept offers potential fuel benefits in combination w...

Coflow and counterflow methane–air flames are simulated over a complete partially premixed regime in order to characterize the effects of dominant combustion modes (i.e., single-, two-, and three-stage combustion) on NOx emissions. Simulations employ a comprehensive numerical model that uses detailed descriptions of transport and chemistry (GRI-2.11 mechanism) and includes radiation effects. It...

The emission control of NOx in exhaust gases is one of the greatest engineering challenges to extend the practical and commercial application of diesel and lean burn engines. One solution is selective NOx reduction using hydrocarbons in an oxidizing atmosphere. We mainly focused on catalytic reactions under temperature excursion because of the resemblance to conditions prevailing in real automo...

Forty light-duty gasoline vehicles (LDGVs), ninety two diesel trucks (DTs), and twenty rural vehicles (RVs) were measured in Beijing, Xi’an, and Shenzhen in China using a portable emissions measurement system (PEMS). We obtained gaseous emission factors (EFs) for LDGVs of different emission control technologies (including Euro 0, Euro I, Euro II, Euro III and Euro IV), and EFs of fine particula...

Fleet fuel consumption is greatly reduced through the introduction of the HSDI Diesel engine. The reduced fuel consumption is then reflected in a reduction of CO2 emissions. The drop in fuel consumption and CO2 emissions results in a rise in market acceptance, which is also the result of desirable driving performance and greatly improved NVH behavior. The continuously increasing demands on plac...

A detailed chemistry-based CFD model was developed to simulate the diesel spray combustion and emission process. A reaction mechanism of n-heptane is coupled with a reduced NOx mechanism to simulate diesel fuel oxidation and NOx formation. The soot emission process is simulated by a phenomenological soot model that uses a competing formation and oxidation rate formulation. The model is applied ...

The impact of convection on tropospheric O3 and its precursors has been examined in a coupled chemistryclimate model. There are two ways that convection affects O3. First, convection affects O3 by vertical mixing of O3 itself. Convection lifts lower tropospheric air to regions where the O3 lifetime is longer, whilst mass-balance subsidence mixes O3-rich upper tropospheric (UT) air downwards to ...