With the advancement and development of universal modern industry, the problem of environmental pollution is getting worse. Besides emission of industry, emission pollution of vehicles and motorcycles is increasingly noticed. The corresponding emission rules of law are also increasingly strict. From 2009, the minimum emission value of two-wheel motorcycle is regulated in Pakistan by EPA (Environmental Protection Agency, of Pakistan).
Exhaust pipe emission includes CO (Carbon Mono oxide), HC (Hydro Carbons), NOx (Nitrogen Oxide) and CO2 (Carbon Dioxide).
Emission from vehicles are controlled through as per standards of Pakistan Environment Protection Agency (PAK-EPA) under clause (e) of session 6(1) of the Pakistan Environment Protection Act, 1997, and with the approval of the Pakistan Environment Protection Council, established national environmental quality (NEQS) as follows:
Structure and working principle of EURO-II (emission control unit, ECU):
Emission control unit mainly includes air pump, air cleaner, connecting pipe and accelerant-catalyzing device.
The air pump, in accordance with the principle of engine ripple control, controls the air flow volume. Fresh air could be inhaled into the exhausted pipe and mixed with the un-burnt CO, HC which exhausted from combustion room. This device could help to reduce the exhaust emission of motorcycle and to reach the Euro-2 emission standard.