Tenneco touts E85 instead of DEF

Lake Forest, Ill.-Tenneco Automotive is promoting a competing technology for diesel exhaust fuel (DEF) used in selective catalytic reduction. According to Tenneco, the new hydrocarbon lean NOx catalyst system for diesel emissions control uses E85, which is 85 percent ethanol and 15 percent gasoline, as a reductant. A Tenneco engineer explained that diesel fuel as a reductant can attain moderate NOx reductions, but E85 can achieve significantly better conversion numbers. He said exactly why E85 works so well for NOx abatement is not yet fully understood, but its oxygen content and volatility are thought to be major factors. Urea SCR systems typically use copper- or iron-based catalysts, but Tenneco’s system employs a unique silver-based catalyst. General Electric is the producer, but Tenneco has exclusive rights to this specific catalyst formulation from GE for a majority of the on- and off-road emissions control markets, except large locomotive applications. The intention is to use both diesel fuel and E85 in the same exhaust system and catalyst. Typically, diesel fuel would be used for NOx control under light loads, while E85 would come into play during heavier loads and stop-and-go cycles. Another advantage E85 has over urea is its ability to withstand lower temperatures, which means that the storage tank on the vehicle would not require the heaters and heated lines that DEF tanks need.