BS4 Vs. BS6: Key Difference Between BSIV and BSVI Engine

How is BS6 Different from BS4?

Bharat Stage Emissions Norms (BS) is the organization that regulates the emission for vehicles in India. The BS4 and BS6 engines were introduced to reduce vehicle emissions, pollution levels, and save the environment.

BS6 engine is a major step taken by the Indian Ministry of Road Transport and Highway (MoRTH) to improve the air quality and reduce emissions. In comparison to the BS4 engines, BS6 engines adhere to stricter norms that help in lower levels of pollutants like nitrogen oxide (NOx), particulate matter (PM), and other harmful gasses. The government mandated that all bikes registered and sold after 1 April 2020 follow the BS6 compliant. Once you purchase a new bike, it will typically be running on a BS6 engine. You must also ensure to buy a bike insurance policy when you finally get your bike.

BS6 emission norms are stricter than the BS4 criteria and help to reduce NOx emissions by 70% in diesel two wheelers and by 25% for petrol engines. Thus a BS6 engine emits five times lower sulphur traces than a BS4 engine.

Key Differences Between BS4 and BS6 Engine

It is quite crucial to understand which one is better while comparing the BS4 vs the BS6 engine. The following table highlights the difference between the two in a detailed manner:

BS6 vsBS4 Engine Pollution Emission Levels

The B6 engine emits less pollutants as compared to the BS4 engine. The table below depicts the emission levels of both BS6 and BS4 engines.

How Does a BS6 Engine Work?

Given the high pollution levels in India, BS4 norms despite being stringent couldn’t be sufficient. The BS6 norms introduced by MoRTH are expected to reduce NOx, PM levels along with reducing the sulphur traces.

The BS6 norms also claim to reduce NOx levels by 25% in petrol engines and by 68% in diesel engines. It is also anticipated that PM emissions will fall by 80% in diesel vehicles.

In the BS6 engine, the converter assists the Selective Catalytic Reduction (SCR) mechanism present in the Nitrogen Oxide to transform into Diatomic Nitrogen or H2O. In this, the SCR system uses fuel fumes fluid to minimize the NOx levels.

If the exhaust fumes come in contact with AdBlue liquid, the urea is transformed into CO2 or ammonia. The NOx is also transformed into nitrogen and water vapours, which helps minimize the emission.

Why Do We Need a BS6 Bike Engine?

With the advancement in engine technology, BS6 has made significant improvements in every aspect. Under this norm, two-wheeler manufacturers must install gasoline injection systems to reduce toxic exhaust emissions.

As the BS6 bike engines are powerful and more fuel-efficient, they have reduced environmental carbon emissions. Ultimately, this emission norm has improved the overall performance of a two-wheeler.