1What is CNG?
CNG stands for Compressed Natural Gas. It is a gaseous fuel and is a mixture of hydrocarbons – mainly Methane. For use in Automobiles as fuel, it is compressed to a pressure of 200-250 Kg/cm2 to enhance the vehicle’s onboard storage capacity.
2Is CNG safe?
Yes, it is safe. The properties of CNG make it a safe fuel. It is lighter than air, so in case of a leak it just rises up and disperses into the atmosphere. Besides, a high auto-ignition temperature of 540°C as against petrol’s 360°C makes it a safe fuel. Also, in case of a leak, if CNG’s concentration in the air is less than 5% and more than 15%, the gas will not burn even in the presence of a spark.
3What is involved in converting a vehicle to a CNG-friendly one?
All spark-ignited engines can be converted to CNG, but a specially designed conversion kit is required for the purpose. The kit consists of a cylinder to be fixed in the boot of the car and other equipment to allow gas flow into the engine. Of late, research is on for converting diesel-run vehicles to dual-fuel with CNG.
4Can a car, fitted with CNG conversion kit, run on Petrol after its CNG gets over?
Yes, after conversion to CNG the vehicle can run on petrol whenever desired simply by flicking a switch on the dashboard. These are called dual-fuel vehicles.
5What is the cost of converting a vehicle to a CNG-friendly one?
The cost of converting a vehicle to CNG depends on its type and make, and may range anywhere from 26,000.00 to around 50,000.00
6What are the dimensions and weight of a CNG cylinder?
CNG cylinders are manufactured from a special steel alloy and are seamless in construction. Their compact size allows them to easily fit even in a small car. An empty CNG cylinder with a 50 water liter carrying capacity (WLC) weighs 48 kg, with a length of 835 mm and a diameter of 316 mm, and can store approximately 8 to 9 Kgs of CNG – depending upon filling conditions, gas density, etc. The 50 WLC capacity cylinder is the one most regularly used – with cylinders of 45 WLC, 55 WLC, 60 WLC and 65 WLC capacity are used as well.
7What is the mileage from one fill? How does one get to know the quantity of CNG left in the cylinder?
The mileage depends upon city road conditions and may vary from vehicle to vehicle and driving habits. A cylinder with a 50-liter water-carrying capacity is capable of carrying approximately 9 kg of CNG. This is equivalent to 12.5 liters of petrol and will allow a run of about 150-160 km for a medium sized 1300 CC car. Also, many OEM manufactured and retrofitted cars have electronic fuel gauge indicators fitted on the dashboard that give an approximate idea about CNG remaining in cylinders.
8What is the pressure of CNG in a cylinder? Is refueling of a cylinder safe, given the pressure?
CNG cylinders are designed and built in such a way so as to withstand high pressure. The maximum pressure in a CNG cylinder is up to 200 kg/cm2 (g) (about 2840 psi[g]). CNG cylinders are safe as they are manufactured as per specific requirements and tested before use, in accordance with international specifications and standards and they are duly approved by Chief Controller of Explosives. Moreover, these have been provided with a ‘safety burst disc’ such that in case of inadvertent high-pressure/high temperature at the time of filling or at any other time, this disc is ruptured and pressure released. Further, these cylinders are to be re-tested every three years at CNG Cylinder Retesting Cylinders approved by Petroleum and Explosives Safety Organisation (PESO).
9How much will be the saving after conversion to CNG?
The fuel bill on the basis of the average running of the vehicle is reduced by approximately 50 percent after conversion of CNG at the present price of CNG & Petrol in Pune. For detailed savings, please refer Savings Calculator.
10Does CNG kit require servicing?
CNG kit is safe and simple. It gives years of trouble-free operation. It doesn’t require frequent servicing. Just as for all other fuels, it is advised to have routine services. An authorized person should be consulted for service. As per Gas Cylinder Rules, 1981, the cylinder should undergo hydro-stretch testing every 3 years to check pressure tolerance.
11Does CNG have any harmful effect on the engine?
Owing to CNG’s distinct features, it does not contaminate or dilute crankcase oil, giving a new lease of life to the engine. The absence of any lead content in CNG helps avoid lead fouling of plugs, thereby enhancing plug life. One of the important benefits of CNG is that upon entering the engine in the form of a gas (and not as a spray or mist like other fuels), it doesn’t disturb the presence of lubricating oil in the engine and reduces chances of wear and tear.
12Can an existing LPG vehicle run on CNG?
An LPG-fuelled vehicle will not run on CNG as the two fuels are different from each other, have differing calorific values and need different air-fuel ratios for combustion. CNG has to be stored at relatively higher pressure in a cylinder than LPG, so the same cylinder cannot be used for both gases. A vehicle will need specific conversion for CNG operation.
13Where is the tank placed in the car?
The CNG cylinder is fixed in the luggage space of your car. It is fastened with a metal strap so that it does not move while the car is running. As per BIS code, it has to be a permanently fitted tank and should be integral part of vehicle (as per BIS 14899 for fuel tank container and as per LPG/CNG Control order).
14How do I get to know the quantity of CNG left in my cylinder ?
An electronic fuel management system is installed as part of the CNG conversion kit in your vehicle on the dashboard. This system will show you the CNG levels in your vehicle.
15In which countries are natural gas vehicles popular?
Natural gas as a vehicle fuel has a long and established record in Europe, Canada, India, New Zealand, Australia and in USA. Other countries such as Japan, Mexico, Malaysia, Pakistan and Bangladesh are recognizing the benefits of CNG and plan to expand its use.