What is the CNG Dual Fuel System?

Under the CNG Dual Fuel System a compressed natural gas Conversion Kit is added to a vehicle with no major modifications to the vehicle's system. In fact the capability of the vehicle is enhanced to include operating on an alternative fuel ie: CNG

What is CNG and why should I go in for it?

CNG stands for Compressed Natural Gas. It is one of the most viable alternatives to traditional fuel energy resources for the automotive industry. CNG is low in pollutants, high in calorific value and heat yield, economical and available in abundance globally.

Reasons for switching over to this alternate fuel are mainly:

1. Economic benefit: The cost of CNG is almost a third of the cost of Petrol in terms of calorific value resulting in substantial saving in fuel cost, and investment on the CNG kit is paid back in a short period

2. Environment friendly: The use of CNG as a fuel reduces vehicular exhaust emissions significantly. Carbon Monoxide emissions are reduced by 70 to 90% and Hydrocarbon emissions by 40 to 60% as compared to vehicles that use the conventional fuel - Petrol. Carbon Dioxide emissions, a cause for global warming, are also reduced significantly by 10%

3. 100% Income Tax Depreciation: Corporate Organisations, firms, etc. can claim 100% depreciation on a CNG Conversion Kit as this is a pollution controlling equipment. Organisations that buy CNG Conversion Kits should consult their Income Tax Consultants and avail of the depreciation benefits

4. Flexibility and ease of use: The basic engine characteristics of a vehicle are retained while converting it to run on CNG. The vehicle therefore is capable of running either on Petrol or CNG at the flick of a switch on its dashboard.

| Top |

The Fuelling Process

There are very few CNG refuelling stations. Of the ones that exist, there are three basic types. Fast fuelling stations which take five to ten minutes for refuelling, ideal for retail roadside pumps. Slow fuelling stations which take from five to eight hours to fill, ideal for a fleet of vehicles which have a long idling time. Combined Fast and Slow fuelling stations which can cater to both the above categories.

CNG is stored at compression stations which are directly connected with the gas pipeline. Here the gas is compressed to a required pressure and aids fuelling. CNG can also be transported to other retail outlets by cylinder trucks. these trucks carry a number of cylinders which provide CNG to fuel stations which are not connected by pipelines. These fuelling stations could be placed alongside petrol and diesel pumps too. the whole process requires proper infrastructure and transportation.

| Top |

Bi-fuel Possibility

Vehicles can also be operated in the dual mode like Petrol-CNG and Diesel-CNG. Experiments of these kinds have been conducted on vehicles by TELCO, Kirloskar Cummins Ltd., Ashok Leyland, IBP, OIL, Delhi transport Corporation and Gujarat Road Transport Corporation. The results were quite satisfactory.

The Gas Authority of India Limited (GAIL) has requested vehicle manufacturers to nominate workshops and undertake conversions on their vehicles. The actual performance could be monitored by the Indian Institute for Petroleum (IIP), Kit suppliers from Italy and New Zealand have joined hands with oil marketing companies and vehicle manufacturers to train and initiate conversion from petroleum products to CNG.

Many countries around the world, including India, have abundant reserves of natural gas. Hopefully, it is only a matter of time when things begin to take a turn for the better and CNG would be as prevalent as petroleum products.

|Top|

What does the kit comprise of ?

1. The Cylinder

The cylinder is used to store CNG at a working pressure of 200 bar. It is fitted with a shut-off valve and a safety burst disc. The cylinders are type approved by the Chief Controller of Explosives, Government of India

2. The Vapour Bag

Fitted onto the cylinder, the Vapour Bag is used to enclose the cylinder valve and the pipes connecting it and is vented out of the car

3. The High Pressure Pipe

This High Pressure Pipe connects the refuelling valve to the CNG Cylinder and Pressure Regulator

4. The Refuelling Valve

The Refuelling Valve is used to refuel the CNG cylinder

5. The Pressure Regulator

The Pressure Regulator has a Solenoid Valve to shut-off gas supply to the engine. The CNG stored at a high pressure in the cylinder is reduced to just below atmospheric pressure by this unit. This negative pressure is also a safety feature that will not allow gas to pass through when the engine is not running

6. The Gas-Air Mixer

The Gas-Air Mixer is a unique component, specially designed to suit each engine model. It precisely meters gas fed into the engine

7. The Petrol-Solenoid Valve

The Petrol-Solenoid Valve is used to cut off petrol supply to the engine when it is run on CNG

8. The Selector Switch

The Selector Switch is fitted at the dashboard, enabling the driver to choose either the CNG mode or the petrol mode of operation. The electronics built into this unit also ensures safety by switching off the gas solenoid whenever the engine is switched off. It also serves as a fuel indicator for the quantity of CNG available in the cylinder

|Top|

Do's and Don'ts for CNG conversion

Ensure that the workshop is authorised and observes Safety Standards and Code of Practices in kit installation and commissioning.

The kit, including the cylinder must be of the type approved for the make of the car. Do not buy components from different sources and install the kit yourself.

Ensure that the car undergoes the required pre-conversion checks thoroughly. After the connections are made, ensure a complete and thorough leak test of the gas system.

Installer's certificate must be collected from the workshop.

Any modification or improvisation should only be done at an authorised workshop.

Acquaint yourself with the mechanism of CNG and the precautions essential for a CNG vehicle. Follow them strictly.

In case of an accident, get the vehicle thoroughly checked by an authorised workshop and obtain re-certification.

Do not install an LPG, Propane or any other cylinder in place of a CNG cylinder. It is illegal and unsafe.

Additional premium is charged by the insurance company for CNG run cars. One should run the vehicle only after the risks of the additional CNG kit system are covered by the insurance company.

Disadvantage CNG