Yearly Archives: 2007

The first reductions in vehicle exhaust emissions were achieved by improving engine design and tuning, but to reach the massively reduced levels of today, new add-on technologies had to be developed to attack specific pollutants and remove or chemically convert them. Often these had to be different devices, or combinations of devices, for the different kinds […]

Evaporation of gasoline from the fuel system is potentially a much greater source of airborne hydrocarbons than tailpipe emissions, so modern gasoline vehicles are equipped with fuel systems which are fully closed and designed to maintain a stable fuel tank pressure without allowing vapour to escape to the atmosphere. A canister of activated charcoal absorbs […]

Three-Way Catalysts a 3-way catalytic converter (“catalyst”) is now standard on every gasoline-engined vehicle. The catalyst uses a ceramic or metallic core (known as a “substrate”) with a coating containing the precious metals, platinum, palladium and rhodium. These metals are the actual “Catalysts” that give the converter its name. They promote the required chemical […]

Particulate filters or Wall-flow Particulate filters remove particulate matter from the exhaust by filtration. They have a honeycomb structure like a catalyst substrate but with the channels blocked at alternate ends, which forces the exhaust gas to flow through the walls between the channels, filtering over 90% of the particulate matter out. The filters are […]

Exhaust Gas Recirculation technology is able to reduce diesel nitrogen oxide (NOx) emissions by taking a carefully controlled portion of the inert exhaust gases, cooling it and re-introducing it to the combustion chamber when conditions are right to do so. This reduces the high concentration of Oxygen and the high temperatures in the combustion chamber, […]