Techniques to Control Emissions from a Diesel Engine

Abstract

Diesel particulate and NO x emission cause several serious health problems; therefore, it is necessary to reduce these emissions from the tailpipe. In the past decades, significant technological advancements have been made in the field of engine emission control. In modern diesel engines, smarter electronic fuel injection strategies are being employed. Control of engine emissions can be put under two baskets: (1) active control techniques, and (2) passive control techniques. Active control techniques are those which restrict the formation of the pollutants in the combustion chamber itself. Passive control techniques refer to after-treatment devices. Active control techniques include advancement in the combustion chamber design, use smarter electronic fuel injection system, exhaust gas recirculation, high-pressure multi-fuel injection with precise injection timing, homogenous charge compression ignition, etc. which if used properly restrict the formation of the pollutants. Some other in-cylinder technologies are also effective in reducing the pollutant emission. Although active control techniques are able to reduce the emission up to some extent, but in order to meet the modern emission regulations, passive techniques are also required in addition to active techniques. Passive control technique involves after-treatment devices like diesel oxidation control, diesel particulate trap, NO x absorber, selective catalytic reduction.