Diesel Engine Applications

The Need for Diesel Emissions Control

Diesel engines require unique emissions aftertreatment to meet the stringent global emission standards.  Aftertreatment systems can be used in both on-road vehicles (cars and trucks) and non-road equipment (agricultural, mining, construction, power generation, and stationary equipment) powered by diesel engines. These systems are used both for retrofit of existing equipment or vehicles and as original equipment for manufacturers (OEMs). Aftertreatment systems generally consist of the following:

• Diesel oxidation catalysts (DOCs). Diesel Oxidation Catalysts (DOCs) oxidize gaseous un-burned hydrocarbons and carbon monoxide into carbon dioxide and water.
• Diesel particulate filters (DPFs). DPFs are used to capture particulate matter and periodically burn it off into harmless gases.
• NOx reducing catalysts like selective catalytic reduction (SCR) or lean NOx trap (LNT). SCR and LNT reduce engine NOx emissions by advanced catalytic reactions employing an additive like urea or my manipulating engine air fuel ratios.
• Multi-function filters (MFF). MFFs generally combine two or more of the above aftertreatment components into a single unit. MFFs require high porosity substrates due to the large quantity of catalyst washcoat necessary.

Companies in these markets and their suppliers are struggling to find cost-effective solutions to meet the new EPA and EURO diesel regulations. GEO2 CLM based substrates are particularly well-suited to these applications because of their compromise breaking benefits which include:

High Soot Capture Efficiency at High Porosity

GEO2 high porosity DPFs are designed to meet the high filtration efficiency needs of worldwide regulated markets including the most stringent EPA and EURO based standards. GEO2 CLM based materials have greater than 95% (mass based) and greater than 99% (number based) filtration efficiency in the range of combustion generated particles (soot particulates and condensed aerosols from nano-meter size ranges to > 2.5 microns.)

Reduced Backpressure

Backpressure from the DOC/DPF system robs engines of fuel efficiency and power. GEO2’s CLM based materials are designed to have lower backpressure than every commercially available DPF. The interconnected pore structure of CLM materials allows many more available passageways for the exhaust gas to flow through, resulting in higher permeability and lower backpressure as soot loads the DPF.

Thermal and Mechanical Robustness

CLM based materials have good thermal and mechanical robustness due to their fiber based microstructure and high temperature strength. The composite materials have high meting temperatures (>1500C), low elastic modulus and high modulus of rupture to withstand high temperature gradients without failure.

Resistance to Ash Corrosion

GEO2’s fiber composite filters and catalytic hosts use materials that are resistant to corrosion in acidic or basic chemical environments. This makes GEO2 technology ideal for use in chemically harsh environments such as diesel exhaust.

Less Cost and Weight

High porosity CLM based materials weighs less than the leading DPFs and can significantly reduce both unit and total system cost. In addition, when used as a multi function filter, CLM materials can eliminate one or more aftertreatment components.

More Information:

The Relationship Between Microstructure and Fracture Toughness for Fibrous Materials for Diesel Particulate Filters

Click here to view paper

Advanced High Porosity Ceramic Honeycomb Wall Flow Filters

http://www.sae.org/technical/papers/2008-01-0623