WHAT TECHNICAL CHANGES NEED TO BE DONE TO UPGRADE FROM BS-III TO BS-IV

What needs to be done to upgrade from BS-III to BS-IV

In an innocuous tweet on Wednesday, Union Transport Minister Nitin Gadkari let the cat out of the bag with the announcement that the country will "leap-frog to BS-VI directly from 01/04/2020".

That is good news considering the pollution levels in the National Capital Region.

What are BS norms?

Bharat Stage emission standards, introduced in 2000, are emission standards that have been set up the Central government to regulate the output of air pollutants from internal combustion engine equipment, including motor vehicles. The different norms are brought into force in accordance with the timeline and standards set up by the Central Pollution Control Board which comes under the Ministry of Environment and Forests and Climate Change.

The Bharat Stage norms are based on European regulations. In 13 major cities, Bharat Stage IV emission standards were put in place in April 2010. BS-IV norms were supposed to come into effect nationwide from April 2017.

Difference in BS-IV and BS-VI standards

The BS norms have been similar to Euro norms till now, and with norms after BS-IV not defined yet, we compare the existing BS-III and BS-IV norms in India with the Euro 6 norms on which India's emission norms have been set.

Petrol Emission Norms (All figures in g/km)

Emission Norm	CO	HC	NOx	HC+NOx	PM
BS-III	2.30	0.20	0.15	---	---
BS-IV	1.00	0.10	0.08	---	---
Euro 6	1.00	0.10	0.06	---	0.005

Diesel Emission Norms (All figures in g/km)

Emission Norm	CO	HC	NOx	HC+NOx	PM
BS-III	0.64	---	0.50	0.56	0.05
BS-IV	0.50	---	0.25	0.30	0.025
Euro 6	0.50	---	0.06	0.17	0.005

Source - Indian Emissions Regulations/ARAI 

CO emissions are Carbon Monoxide emissions are are more evident in Petrol engines. Long Term exposure can prevent oxygen transfer and increase headaches/nausea.

HC emissions are Hydrocarbons which are again more prevalent in Petrol engines. Short term exposure can cause headaches, vomiting and disorientation.

NOx emissions are Nitrogen Oxide emissions which are more prevalent in Diesel engines. Long Term exposure can cause Nose and eye irritation and damage lung tissue.

PM is Particulate matter, again more prevalent in a Diesel engine. Long Term exposure can harm the respiratory tract and reduce lung function.

How will BS4 engine be less polluting from BS3 engines?

 

1. BS-IV petrol and diesel essentially contains less sulphur, a major air pollutant. Sulphur also lowers the efficiency of catalytic converters, which control emissions.
2. Broadly, BS-IV petrol and diesel have 50 parts per million (ppm) of sulphur, as compared to 150 ppm for petrol and 350 ppm for diesel under BS-III standards. 
3. The technology that will be used in future BS-VI vehicles, though, will have considerable impact, they claim. BS-V diesel vehicles were to have engine upgrades, particulate filters, lots of sensors, and electronic control. 
4. Petrols were to have catalyst and electronic control upgrades.In India, where small cars are preferred, fitting DPF(Diesel particulate filter) in the limited bonnet space would involve major design and re-engineering work. 
5. BS-VI vehicles also have to be equipped with an SCR (Selective catalytic reduction) module to reduce oxides of nitrogen, which is done by injecting an aqueous urea solution (AUS 32, which contains ammonia) into the system when the exhaust is moving. 
6. At every stage, the technology is getting more complex. To attain the specified super low emissions, all reactions have to be precise, and controlled by microprocessors.