Exhaust gas purification system for internal combustion engine

摘要

The system minimises emission of hydrocarbon compounds, carbon monoxide and nitrogen oxides in the exhaust of an Otto engine. Fresh air is introduced into the exhaust system via a pump (10). The air flows via a pipe (11) with branches which enter the exhaust pipe (5,6) just downstream of the exhaust valve. The exhaust gas-air mixture passes a lambda sensor, just before the catalytic converter (7) which measures the proportion of oxygen in the exhaust gases. The lambda sensor is connected to an engine control circuit (8) which is connected to the accelerator pedal (9) and the air pump. It controls the speed and the power of the engine and keeps the value of lambda between 1.1 and 1.3.