80 HP PLASMA ASSISTED CATALYST SYSTEM

The US economy is linked to efficient heavy vehicle transportation and diesel remains the fuel of choice for mass transportation of goods and services. Diesel engines remain the most reliable and cost effective system for commerce. Recent deleterious effects of diesel exhaust on health and environment have led to an urgent need for cost effective technologies that would bring about reduction in NOx and PM. CARB estimates on-road diesel mobile source will contribute almost 50% NOx and 78% PM emissions by 2010. As a result recent Federal and State mandates have been adopted to reduce emissions from diesel exhaust to 1 Gm/bhp.-Hr of NOx and 0.05 Gm/bhp-hr of PM by the year 2007. The 2007 standard is to be achieved in a stepwise manner starting with the standards for 2002 namely 2 Gm/bhp-hr NOx and 0.1 Gm/bhp-hr of PM. 2002 standards are likely to be met by most engine manufacturer by some modified form of exhaust gas recirculation (EGR) system or by employing a sophisticated engine control system. Importance of cost effective technology requirement is further exaggerated by the fact that in recent years diesel engine production have increased dramatically see figure 1 and has out stripped the gasoline engine production almost 4:1 see figure 2. Currently gasoline engine employs a 3-way catalytic system for NOx and HC reduction and in order for the 3-way system to work the engine is run near stoichiometric air : fuel ratio so that exhaust has virtually no oxygen. This strategy has resulted in a poorer efficiency and hence less efficient utilization of our natural resources. By contrast diesel engine operate on a lean burn principals i.e. air rich and currently there are no commercial technologies available for treating NOx and PM. Technologies being considered for reducing NOx from lean burn (diesel) exhaust are; Lean NOx catalyst systems, NOx adsorber system, Selective Catalytic Reduction systems and plasma assisted catalyst system. Of all these technologies Plasma assisted catalyst system is probably the most attractive since it can use currently available fuel onboard