The increasing pollution level is a one among the key concerns of the government across the globe. Various factors augment to this pollution, however, automotive emission is the major contributing factor for the pollution. The major pollutants comprise oxides of nitrogen, oxides of sulphur, oxides of carbon (CO and CO2), particulate matter, volatile organic compounds (VOCs) and hydrocarbons (HC). With the stringent emission standards such as Euro-6 coming into existence the OEMs is stressed to manufacture vehicle which comply with the norms. The companies are hugely investing to design more advanced emission control systems, while embedding sensors such as NOx sensors, oxygen sensors, soot sensors, gas sensors and few more to control emissions.
These sensors in combination with catalytic convertor and powertrain control module (PCM) help reduce the harmful contents in the vehicle exhaust. Different pollutants are produced in different conditions like incomplete burning of fuel produces hydrocarbons, a lean mixture produces NOx, burning in limited oxygen produces CO and so on. The treatment of each type of pollutant is different and this is where the sensors play a prominent role in reducing emission. For instance, oxygen sensor (Air-Fuel Ratio type) detects the air fuel ratio in the cylinder and sends the signal to PCM.
The most preferred method used to control the emission level is by using an oxygen sensor in the exhaust chamber. This system uses a three way catalytic convertor; it uses oxidation catalyst to burn HC and CO and reduction catalyst to break NOx. The oxygen sensor sends either of the two signals to the PCM lean or rich. The PCM keep flipping the air/fuel mixture from rich to lean depending on the signal from the oxygen sensor. When the air-fuel mixture is rich the amount of HC (hydro-carbon) and CO (carbon-monoxide) goes down; the reduction catalyst breaks down NOx. On the other hand the oxidation catalyst uses oxygen to burn HC and CO; this makes the mixture lean. The oxygen send lean signal to PCM; PCM flips the air/fuel mixture to rich. When oxygen sensor sends rich signal the PCM reduces the on-time of fuel injectors and makes the mixture lean. This frequently changing of air/fuel mixture helps to bring down the emission value to minimum.
Owing to the stringent emission norms automotive sensors market has witnessed significant growth in terms of value and volume, particularly, in fuel emission system. With the rapid advancement such as enhance safety, anti-lock brake system (ABS), airbags and emission norms compliance are likely to propel the market for automotive sensors in coming years.