BS4 vs BS6: Key Differences Explained

Have you ever felt a little choked up after a long ride in heavy traffic? Vehicle emissions are a major source of air pollution, impacting everyone on the road. But there’s good news for eco-conscious riders!

Here’s a breakdown of the two main players: BS4 and BS6 emission standards. Think of them as guidelines for how clean your two-wheeler’s or four-wheeler’s breath needs to be. For an eco-conscious ride, it is crucial to understand the differences between BS4 and BS6 

• BS6 Fuel: BS6 is the cleaner-burning fuel for your ride. It contains significantly less Sulphur (five times less) than BS4 fuel. This translates to less harmful pollutants coming out of your exhaust.
• BS6 Engines: BS6 engines are designed to release much less nitrogen oxide (NOx), a major air pollutant. BS6 petrol engines cut down NOx by 25%, and diesel engines by a staggering 70%.

The bottom line? BS6 is all about cleaner air for you, your fellow riders, and the environment. It’s a win-win for everyone, making your ride and our cities a breath of fresh air!

What is BS4 (BSIV)?

The BSIV regulations introduced changes to tailpipe emissions, Electronic Control Units (ECUs), ignition controls, and more. The most visible change was the Automatic Headlamp On (AHO) standard, which aligned with BS4 and addressed safety concerns under the new emission norms.

What is BS6 (BSVI)? 

The sixth generation of the emission standard, referred to as BS6, offers an important advance over the previous BS4 emission standard in terms of reducing air pollution. This is also a result of the BS5 (BSV) being removed in an attempt to move towards more advanced emission standards.

Pollution Emission Norms (BS4 vs BS6)

BS6 regulations are a stricter upgrade to BS4 standards, significantly reducing vehicle emissions. Here’s a breakdown of the key differences:

• Fuel Requirements: BS6 vehicles require BS6 fuel to meet emission limits. Using BS4 fuel in a BS6 car will cause it to exceed legal emission levels.
• Real-World Testing: BS6 introduces Real Driving Emission (RDE) testing. It measures emissions in real-time driving conditions, unlike BS4’s lab-based testing.
• Reduced Emissions: BS6 allows only 60 mg/km of nitrogen oxides (NOx) from petrol vehicles, compared to 80 mg/km in BS4. Additionally, BS6 limits particulate matter (PM) to a mere 4.5 mg/km for petrol vehicles.
• Stricter Diesel Limits: BS6 drastically cuts diesel emissions. While BS4 allows 250 mg/km of PM, BS6 restricts it to 80 mg/km. BS6 also reduces combined hydrocarbon (HC) and NOx limits for petrol from 300 mg/km to 170 mg/km.

Differences Between BS4 and BS6 – Pollution Emission Norms 

BS6 Slashes Pollutant Limits

Compared to BS4, BS6 regulations significantly tighten restrictions on vehicle emissions. Diesel car emissions are drastically reduced, with BS6 allowing only 80 mg/km compared to the much higher 250 mg/km permitted under BS4. This represents a whopping 68% decrease! BS6 also applies stricter limits to other pollutants. 

Particulate matter (PM) is capped at a mere 4.5 mg/km, down from 25 mg/km in BS4. Additionally, the combined limit for hydrocarbons (HC) and nitrogen oxides (NOx) is reduced from 300 mg/km to 170 mg/km. These substantial reductions translate to cleaner air and a healthier environment. 

Effects of BS6 Emission Standards

Impact of BS6 Emission Standards On Diesel Vehicles 

• Due to changes applied to the exhaust system, the cost of diesel vehicles in keeping with BS6 increased relative to BS4 vehicles. 
• BS6 automobiles include a Diesel Particulate Filter (DPF) to minimize soot emissions. Sulphur emissions would be decreased by the exhaust system.
• Diesel automobiles reduce NOx using SCR devices. 

Impact of BS6 Emission Standards on Petrol Vehicles

• Petrol cars that comply with BS6 standards were costly with the launch of Electronic Fuel Injection (EFI).
• The combustion process and emissions of the gasoline engine were greatly decreased with the switch to the more demanding BS6 emission norms.
• The outdated motor had been replaced with Electronic Fuel Injection (EFI).  
• Better engine combustion led to a small increase in fuel economy.

Impact of BS6 on CNG Cars

The shift to BS6 emission standards has a minor impact on CNG (Compressed Natural Gas) cars. Here’s a breakdown:

• Small Tweaks for CNG Engines: Car companies just need to make minor adjustments to CNG engines to meet BS6. Think of it like fine-tuning the engine to run smoothly on the cleaner BS6 fuel.
• A Bridge to Cleaner Cars: BS6-compliant CNG vehicles are like a stepping stone. They’ll be around until electric and hybrid cars become more common. That’s because CNG is already cleaner than regular gasoline or diesel, even before BS6.
• Cleaner Ride Ahead: You can expect to see BS6-compliant CNG cars hitting the market soon. These new models will be even better for the environment compared to older BS4 gasoline or diesel cars.

Can BS6-grade fuel be used in BS4 vehicles?

If you own a gasoline-powered BS4 car with fuel injection, you can breathe easily! 

BS4 and BS6 gasoline are very similar, so your car will still run fine with BS6 fuel. However, things are a bit different for BS4 diesel vehicles.

Here’s the issue: BS4 diesel fuel contains more sulphur (50 parts per million) compared to BS6 fuel (10 parts per million). While this lower sulphur content is good for the environment, it can cause problems for BS4 diesel engines.

How do BS6 emission norms differ from BS4?

• With the start of Bharat Stage VI rules, two new techniques that were not included in Bharat Stage IV are Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR).
• When Bharat Stage VI emission limits are put into impact, Real Driving Emissions (RDE) will be introduced in India. It will compare the emission levels of a car in real life to those in a lab.
• The introduction of Bharat Stage VI emission rules has resulted in a further change where Onboard Diagnostics (OD) is now required for every vehicle.

Takeaways on Differences Between BS4 and BS6

The primary change brought about by the adoption of Bharat Stage VI emission standards is a shift in the fuel used in automobiles. A car with an engine that complies with BS6 criteria needs BS6 fuel.

By adopting pollution emission norms, the government has made the right choice to reduce pollution for environmental safety. Individuals who own gasoline-powered vehicles with BS4 engines don’t need to worry. You can utilize BS6 petrol in these automobiles. The fuel’s hardly noticeable changes to its chemical composition are the cause. The simple response is that automobiles with BS6 engines won’t be distributed after April 2020. The manufacturers are being requested to cease producing BS6 vehicles, as it relates to them. Never forget that improper and incomplete combustion results in a changed fuel flow pattern, which increases the emission level. Thus, upgrade yourself as well.

Frequently Asked Questions

What are the differences between BS4 and BS6 fuel?

BS6 fuel has a lower sulfur content (10 ppm) compared to BS4 fuel (50 ppm). The lower sulfur content is necessary for the advanced emission control systems in BS6 vehicles to function correctly.

Is BS6 mileage better than BS4?

Not necessarily. BS6 mileage can be better, worse, or the same compared to BS4 for a few reasons:

• Focus on emissions: BS6 standards prioritize reducing pollution, which can sometimes lead to slight adjustments in engine performance that might affect fuel efficiency.
• Engine design: Manufacturers can implement various technologies to meet BS6 norms, and some of these might improve or decrease fuel economy depending on the specific design.

Which is superior – BS4 or BS6?

The sulphur content in BS6 fuel is 10 parts per million, a fivefold reduction from the 50 parts per million in BS4 fuel. As a result, BS6 gasoline is more environmentally friendly than BS4. It lessens emissions of hazardous pollutants and has a lower sulfur content.

How to identify a BS4 or BS6 engine?

Look at the Vehicle Identification Number (VIN), Production Date, and RTO Form 21, you may determine if your vehicle complies with the BS4 and BS6. 

Can I still buy a BS4 car?

No, since April 1st, 2020, only the sale and registration of new BS6 vehicles are allowed in India.