Hot Smoke results from incomplete combustion during heavy engine loads. Hot smoke also results from an over-rich fuel mixture. Insufficient oxygen prevents the diesel fuel from completely oxidizing. Traditional engine adjustments do nothing to hot smoke production. Fumigation reduces most hot smoke production resulting in reduced pollution and increased vehicle mpg.
Cold smoke produces the same emission pollutant particulate matter.
Fumigation does not abate cold smoke. Mandated reductions have forced manufacturers to reexamine the diesel engine combustion process to discover answers. For four-stroke diesel engines, fumigation is a relatively low cost and easily adaptable solution. A fumigation system injects a gaseous or liquid fuel into the intake air stream of a compression ignited engine. This fuel burns and becomes a part-contributor to the power producing fuel.