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Infographic - Know all about the CNG in Automobiles

Snapshot: We will discuss various aspects of Compressed Natural Gas, from its importance to the cost of running viz-a-viz other fuel options.

Once the Indian car market was dominated my petrol cars as the diesel cars were regarded to be crude vehicles. The spiraling fuel costs for petrol led to the diesel car revolution in the country which also resulted in the refinement of the diesel engines. Now, that the cost woes are quite alike for both petrol and diesel fuels, CNG kits have emerged as the saviors for the cost conscious Indian populace. CNG powered car revolution is thought to soon happen in India.

We will discuss various aspects of Compressed Natural Gas, from its importance to the cost of running viz-a-viz other fuel options.

What is CNG?
CNG means Compressed Natural Gas is nothing but Methane stored at high pressure. CNG is often touted as the best alternative to power a car in place of Petrol, Diesel, and LPG (liquified petroleum gas). The gas is collected in free form from the oil deposits and then compressed to less than 1% and stored in a tank. CNG is safer than the other form of fuels and also is more greener as it produces less gases in combustion as compared to the traditional gases.

Why CNG?
There are numerous reasons why the CNG is popularly used in many commercial vehicles as well as passenger cars. Some of them are:

1. CNG is a much cheaper fuel option as compared against petrol or diesel.

2. CNG is a cleaner fuel than diesel and petrol.

3. It is definitely a much more environmentally friendly fuel and its cleaner form also helps in preserving the vehicle’s engine for longer, thus it is economical and eco-friendly from all aspects.

4. CNG has much less auto-ignition temperature and cuts down the chances of accidental automobile fires, making it an overall safe fuel.

Apart from this, CNG is a much newer fuel option and there are many more benefits that you can get out of the very cost effective CNG powered vehicles.

How to get CNG in cars?
The CNG cars are high in demand nowadays, and one can opt for it in two ways. One can choose to buy a new CNG only car with a factory fitted CNG kit from the car manufacturer, or petrol cars can also be fitted with a CNG kit from the car dealer. The second option also offers the flexibility of dual fuel and can switch from petrol to CNG and vice versa as desired.

CNG Kit Types
There are primarily two sorts of CNG kits that are available, namely the Venturi kits and the Sequential kits. The CNG kits are also classified as the Open-loop systems and the Closed-loop systems. Let us now take a look at the types of CNG kits.

Venturi CNG Kits
The Venturi CNG kits have a simple design and principle. It pumps out a limited volume of the CNG fuel into the engine’s intake manifold based on throttle. This type of CNG kit works rather like a carburetor. The Venturi CNG kit, is not only more affordable, but is also simpler than the sequential CNG kit types. It is also versatile and can be fitted in all types of vehicles, irrespective of the engine construction type.

Sequential CNG Kits
The Sequential CNG kits are more complicated, but are more accurate than the Venturi CNG kits. The Sequential CNG kit also maintains a very well controlled flow of fuel into the motor’s intake manifold. In order to smartly monitor and to accurately control the flow of the fuel into the engine, a special CNG compliant ECU is employed for the Sequential kits.

Closed-loop Systems
A closed-loop system comes with Oxygen sensors called Lambda sensors for optimal CNG fuel flow. It also monitors exhaust emissions and send the feedback to the ECU which controls the gas flow to minimize the harmful emissions.

Open-loop Systems
These systems don’t have Lambda sensors, thus the exhaust missions cannot be checked in these kits.

Is CNG really the cheapest fuel?
We will try to calculate the running cost and the ownership cost of a CNG system and compare it with other traditional fuel options like the petrol and diesel. Consider a hypothetical condition where a person runs 10000 km on an average in a year. Calculating running cost:

CNG price in India - Rs 38.15/ litre

CNG tank capacity - 8.5 litre

CNG average - 170 km/ tank or 20km/litre

CNG running cost for 10000 km = Rs 19075

Petrol price in Delhi - Rs 61.30/litre

Petrol Average - 12kmpl

Petrol running cost for 10000 km = Rs 51080

Diesel price in Delhi - Rs 50.50/lire

Diesel Average - 17kmpl

Diesel running cost for 10000km = Rs 29705

Clearly, CNG is a winner here, with almost Rs 30000 difference in running cost per year. If a person uses a good aftermarket CNG kit, it costs about Rs 50000 over and above the car cost. So, running the car for two years will get you even and from the next year, one will save all the amount in fuel. 

Documents required for changing from petrol to CNG
Over the last few years, car buyers are opting for cars with Compressed Natural Gas (CNG) fitted kit. But, a lot of paper work is required when you plan to change from petrol (or diesel) to CNG for your car. You need certain documents that need to be submitted at your local Road Transport Office (RTO). Below is a list of documents required for registration:

1. Original Registration Certificate (RC) or smart card of the vehicle. A new RC with new conversions is issued.

2. Original car insurance copy. The car owner needs to inform the insurer about the change. A charge of 4% of the CNG kit's value is levied as extra premium and changes need to be made to the policy.

3. Identity proof of the car owner: passport, voters ID, aadhar card, landline bill, etc. The driver's licence is not applicable.

4. Installation Certificate from the Retro-Fitment Centre (RFC). RFC needs to complete a form that is issued by the RTO.

5. RFC's licence copy is a must.

6. Certificate issued by the Chief Controller of Explosives (CCOE) for the CNG cylinder.

7. CCOE certificate for 'multifunction valve' in case of conversion to LPG.

8. A copy of approval will be required from the Vehicle Research and Development Establishment, International Centre for Automotive Technology or Automotive Research Association of India.

9. Pollution Under Control (PUC) certificate is needed for the petrol mode.

Also, check our artcile on Auto Glossary for beginners!

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