Non road mobile machinery usage of catalytic converters
Last changed: 07 June 2011
Tractors and other non road mobile machinery almost exclusively rely on Diesel engines for the power. These engines are more fuel efficient than petrol engine, but also emit substantial amounts of nitrous oxides (NOX) and particulate matter. These emissions have a negative impact on human health and can cause eutropication and acidification.
In order to reduce these emissions various catalysts can be installed. The most common alternatives are:
- Diesel oxidation catalysts
- Particulate filters
- SCR catalysts
Diesel oxidiation catalyts reduce emissions of carbon monoxide, hydrocarbons and the organic fraction of particulate emissons. Particulate filters reduce, as would be expected, the particulate emissions. These two catalysts are often combined, as the oxidation catalyst heat the exhaust gas, which makes the particulate filter more efficient. SCR catalysts reduce the emission of nitrous oxides.
A distadvantage ofusing catalysts is that they use rare metals that can require substantial amount of energy to produce. In order to operate well they also need a number of conditions to be fulfilled, such as hot enough exhaust gases. The project try to relate the positive environmental impact of reducing vehicle emissions with the negative impact of catalyst production.