Impact of BS VI Emission Norms

Editor@Throttle|Updated: March 22, 2018 9:31

India has the most polluted cities in the world. 30 Indian cities stand in the Top 100 Most Polluted Global Cities (in terms of particulate matter PM10) as per data published by World Health Organization in May 2016. Air pollution is the fifth leading cause of death in India.


India has traditionally been a laggard in terms of enforcing and implementing emission norms for the manufacturing sector. Indian auto industry is not an exception to this either. For instance in the capital city of Delhi, vehicles contribute 59%, 50% and 18% of the overall emissions of carbon monoxide, hydrocarbons and nitrous oxides respectively.


There is a strong opinion emerging among policy makers and environmental groups in India that stricter emission standards need to be implemented for all kind of vehicles in the country. The rising levels of particulate matter, NOx and hydrocarbons need to be curbed to improve air quality index. 



(Image Source :Wikipedia) 


Currently, BS-IV norms are applicable in 13 major cities of the country, while BS-III norms are applicable elsewhere. As per Auto Fuel Policy 2025, BS-VI roll out was envisaged for the entire country by 2017, BS-V by 2021 and BS-VI by 2024. 

However in a bold move in January 2016, the Union Government of India decided to skip BS-V emission norms altogether and leapfrog directly to BS-VI norms by April 2020. The move to BS-VI norms from BS-IV norms will bring down NOx emissions by 25% in petrol engine vehicle and by 68% in diesel engine vehicles. PM emissions, a major component of outdoor air pollution, are also expected to come down drastically by over 80% in diesel engine vehicles. 



 Image Source : Crankit

How will BS VI norms affect motorcycles?


Two-wheeled vehicles, such as motorcycles and mopeds, are the largest vehicle class in India, both in terms of current vehicle population, as well fraction of new vehicle sales. As such, they represent an important source of pollutant emissions and have a significant impact on air quality, particularly in urban areas of the country. As proposed, the BS VI regulations largely align emission limits for two-wheeled vehicles with the most stringent standards adopted for similar vehicle types in the EU, and ensure that these vehicles will generally be no more polluting than BS VI four-wheel passenger vehicles. 



(Image Source : ZigWheels)

BS VI emission standards are set for Class 1-3 two-wheelers equipped with SI( Spark ignition ) engines, which account for the majority of the two-wheeled vehicle population in India, and separately for two-wheelers fitted with CI (compression ignition) engines. Separate standards are also set for two-wheelers with SI engines less than 50 cubic centimeters and maximum rated speed less than 50 km/h. This class of two-wheeled vehicles largely consists of pedal-powered mopeds, which make up a very small fraction of the market.


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In all cases, BS VI standards will apply to vehicles manufactured on or after April 1, 2020. Mass emission limits specified in the BS VI standards can be found on Figures 1 and 2 include comparisons of BS VI and BS IV mass emission limits for CI and SI two-wheelers, respectively. For Class 1-3 SI two-wheelers, BS VI CO, NOX, and HC emission limits are equivalent to Euro 5 limits for similar L-category vehicles, which have been adopted and will be implemented beginning in 2020 for new vehicle types and in 2021 for all vehicles.


This means that, for two-wheeled vehicles, the BS VI regulation essentially harmonizes emission limits, as well as implementation schedules with Europe. Relative to BS IV levels, NOX emission limits for these two-wheeled vehicle classes are reduced by between 70 and 85%. In the BS VI standards, an independent tailpipe HC emission limit of 0.10 g/km is also introduced. 


Image Source : Wikipedia 


In previous regulatory stages, HC emissions from two-wheelers were regulated under a combined NOX+HC standard. By setting independent emission standards for both HC and NOX, BS VI emission standards will help to ensure that emission control strategies do not reduce emissions of one pollutant at the expense of the other. Hydrocarbon emissions from gasoline two-wheelers are further controlled through the tightening of the evaporative emissions limit. 


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Under BS IV standards, manufacturers are able to meet either a 2.0 or 6.0 g/test evaporative emissions limit, with vehicle models meeting the 2.0 g/test subject to less a stringent tailpipe NOX+HC limit. Under the BS VI regulation, all gasoline powered vehicle models are required to meet a 1.5 g/test evaporative emissions limit, and no flexibility provisions are included for meeting tailpipe and evaporative emission limits. These steps will help to reduce complete vehicle HC emissions. As shown, emission limits for diesel and Class 1-3 gasoline twowheeled vehicles are, for the most part, numerically equivalent to limits for light-duty passenger vehicle. Exceptions include a slightly higher NOX limit for CI two-wheelers (0.09 g/km vs. 0.08 g/km for light-duty diesel passenger vehicles), and the omission of a PN limit for two-wheeled vehicles powered by GDI engines. OBD system specifications for two-wheelers are included for the first time in proposed BS VI regulations.


The BS VI regulation also sets OBD emission thresholds for these two-wheeled vehicle classes. Threshold limits are set for CO, NOX, non-methane hydrocarbons (NMHC), and PM, and are numerically equivalent to Euro 5 thresholds for similar L-Category vehicle types. 


Durability mileage for two-wheeled vehicles is set at 35,000 km in the BS VI standards, which represents a moderate increase from the 30,000 km requirement included in the BS IV regulation. This mileage is equivalent to Euro 5 requirements for two-wheel motorcycles with rated maximum speed greater than 130 km/h and exceeds Euro 5 requirements for other two-wheel vehicle types, which are set at either 11,000 or 20,000 km. 


BS VI Fuel Outlook

Fuel standards in BS VI are comparable to EU VI and EPA Tier 3 in specifications. Use of higher injection pressure, electronically controlled injection and advanced after-treatment reduce sensitivity of diesel engines to fuel density. Availability of affordable clean fuel is seen as one of the challenges by OEMs for compliance, while it is expected that the supply chain will stabilize resulting in lower prices, as scale of production increases.


Upgrading to BS VI fuel is expected to make petrol and diesel costlier by Rs 1.40 and Rs 0.63, respectively. Considering the flexible nature of fuel prices after deregulation, this is not expected to make a large impact on powertrain preferences.


BS VI norms for manufacturers


They all need to install electronic fuel injection systems (EFI). So though we do have some fuel injected bikes right now every single new one has to use this EFI system before 2020. The working of the Fuel Injection system is more computerized and works on a lot of sensors. The fuel injection nozzle is provided directly in the combustion chamber. The air intake is measured by the air sensor location inside. There is a pressure pump which pressurizes the fuel which allows it to be atomized and hence inside the combustion chamber, the spray is in the form of a mist which allows for complete and cleaner combustion. The fuel supply is controlled by the ECU which is the computer controlling all the electronics of the bike. So when the air supply is increased when the throttle is pulled, the air sensor detects the increase which data is then fed to the ECU so that accordingly the fuel amount to be injected is increased as well. 



While the shift to BS6 emission norms goes a long way to curb pollution, motorcycle riders must get the PUC ( Pollution Under Control) check done regularly. Continuous exposure to SPM (Suspended Particulate Matter), NOx and CO2 is dangerous and can trigger lung problems and respiratory infections. So it is a good practice to get the PUC done, not just for the sake of challan but good health too!