With all the EU Green rules from the EU coming in to force, its getting close to the end of 2/,s.
The 2-stroke engine emits significant amount of particulate matter (PM), un-burnt hydrocarbons (HC), Carbon Monoxide (CO) and Nitrogen Oxides (NOx). CO and NOxemissions by 2-stroke engines is much lower compared to 4-stroke engines.
PM: Lubricating oil is less combustible than gasoline, some of the oil that is mixed with gasoline will survive to be emitted in the exhaust. This is further worsened locally as engine oil mixed is up to twice the manufacturers recommendations (4%). It is estimated that particulate emissions from a single 2-stroke motorcycle is comparable to those from a diesel truck or bus. PM, particularly the finer ones, are associated with respiratory problems.
HC emissions result from the elements of the air-fuel mixture that fail to burn in the engine due to leakage through the exhaust port, weak compressing causing partial combustion and misfiring (About 30% of the fuel comes out of the exhaust un-burntin 2-stroke engines).
Some gasoline components like benzene are carcinogens, while others combine with NOxto form ozone. Ozone affects the respiratory system, reduces visibility, damages vegetation and contributes to photochemical smog.
Two stroke engines have much higher emissions of PM and HC than 4-stroke engines of similar power and size. In the USA, motorcycle manufacturers switched to making 4-stroke engines in 1978, in response to the adoption of strict emission standards. Other European countries and Japan followed suit.
Emissions from 2-stroke engines can be reduced by rigorous inspection and maintenance programmesand used of lubricating oil of correct quality and quantity. But the best option is to ban the use of 2-stroke engines
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