What is a BS6 Engine & How BS6 Engines work, BS4 Vs BS6

With the increase in the level of pollutants in India's metropolitical cities, the Central Government has decided to strictly guide the automakers to change the manufacturing of vehicles suitable for the Bharat Stage 6 emission norms and like others Bajaj is also following this BS6 norms and all the latest bikes of Bajaj are also BS6 compliant. These norms will replace the current regulations of Bharat Stage 4.

The implementation of lockdown shook the Indian automotive industry because of the pandemic. It is expected to see a significant shift again when everything will come back to normal. In this article, let's understand — what is a BS6 engine?

Difference between BS4 And BS6

The Indian Government came up with Bharat Stage Emission Standards to restrict the increase of pollutants in the atmosphere, especially in metropolitan cities emitted by the internal combustion engines and automobiles' engines.

These standards were designed based on Europe's regulations and are named BS3, BS4 and BS6, respectively. The higher number is used to denote a comparatively critical condition.

But what is the BS6 Engine? The BS4 engine demonstrated greater hope than past standards and mainly focused on reducing the atmosphere's sulfur levels. However, it was not able to meet the criteria to reduce Particulate Matter and Nitric Oxide.

The BS6 engine will meet the standards to reduce NOx and PM levels and will be able to bring down the sulfur level in the atmosphere. This stage will be restricting the emissions from the tailpipe to 1.0g/km of CO.

How does a BS6 engine work?

The working of BS6 is mainly based on Selective Catalytic Reduction units. It is an advanced emissions unit that was developed to control emissions.

The SCR unit in BS6 converts NOx into two parts — water and diatomic nitrogen with the help of AdBlue or diesel exhaust fluid. The diesel fluid comprises urea and deionized water.

When AdBlue is connected with the engine, the area will be converted into Carbon Dioxide and Ammonia. The ammonia later further converts the gases into nitrogen and water vapor and reduces pollutant emissions from the engine.

BS6 Engine: More details

The fuel for BS6 bikes are currently available in most parts of India, and the price difference between the BS6 fuel and BS4 is almost zero. However, it is expected that once BS6 fuel vehicles are set on the road, the oil marketing companies will probably increase the price of the fuel.

Minor changes will be made in the CNG vehicles so that they are compatible with BS6 fuel. And with the onset of this stage, CNG-based BS6 vehicles will have a massive impact on the country's automobile industry.

The sulfur level of BS6 fuels will be lower than the older versions. The sulfur acts as a lubricant that burns effectively. However, some alternatives will be used to make the grease easier with the reduction of sulfur.

About SCR

The SCR or Selective Catalytic Reduction unit is primarily designed for the Engine of BS6 bikes, reducing emissions. The emission of NOx is reduced by increasing the temperature for combustion, which decreases the production of Particulate Matter in the engine. SCR controls the level of NOx using catalytic reduction.


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