Q.1) What is CNG?
Ans. CNG stands for compressed natural gas. It is 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 on-board storage capacity.
Q.2. Is CNG safe?
Ans. 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 degrees centigrade as against petrol’s 360 degrees
centigrade, 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.
Q. 3. What is involved in converting a vehicle to a CNG-friendly
Ans. 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.
Q. 4. Can a car, fitted with CNG conversion kit, run on
Petrol after its CNG gets over?
Ans. Yes, after conversion to CNG the vehicle can run on petrol
whenever desired simply by flicking a switch on the dashboard.
Q. 5. What is the cost of converting a vehicle to a CNG-friendly
Ans. The cost of converting a vehicle to CNG depends on its type
Q. 6. What are the dimensions and weight of a CNG cylinder?
Ans. 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 litre-water-carrying capacity weighs 48 kg, with a length of
835 mm and a diameter of 316 mm. The 50 litre capacity cylinder
is the one most regularly used; cylinders with 45 litre, 55 litre,
60 litre and 65 litre capacity are used as well.
Q. 7. What is the capacity of a cylinder, and mileage from
one fill? How does one get to know the quantity of CNG left in the
Ans. Under city road conditions and may vary from vehicle to vehicle
and driving habits.
Q. 8. What is the pressure of CNG in a cylinder? Is refuelling
of a cylinder safe, given the pressure?
Ans. CNG cylinders are designed and built in such a way so as to
withstand high pressure. The maximumpressure in a CNG cylinder is
up to 200 kg/cm2 (g) (about 2840 pounds per square inch (gauge)
or 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.
Q. 9. How much will be the saving after conversion to CNG?
Ans. The fuel bill on the basis of average running of vehicle is
reduced by 50 percent approximately after conversion of CNG at the
present price of CNG & Petrol in Delhi.
Q. 10. Does CNG kit require servicing?
Ans. 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 under go hydro-stretch testing
every 5 years to check pressure tolerance.
Q. 1. What exactly is LPG and where does it come from?
Ans. 40% of LPG comes from the refining of crude oil and 60% straight
from field production. At atmospheric pressure it is a vapour, under
modest pressure it becomes liquid.
Q. 2. Most of my fleet is diesel powered?
Ans. This is not uncommon, so make the switch when your vehicles
come up for replacement. Let us carry out a cost saving analysis
now so you can see the benefits of changing your fleet to run on
Q. 3. What is going to happen to the price of Autogas in
Ans. The cost of Autogas currently stands at around 45p per litre.
Thanks to its environmental benefits, LPG has found favour with
the government. In 2006 the Chancellor agreed to continue to give
notice 3 years in advance of any changes in fuel duty. As a result,
the price of Autogas at the pumps will continue to be around half
that of petrol and diesel for the foreseeable future. With care
for the environment becoming a higher day-to-day priority, schemes
are also being put in place which see taxation, insurance and parking
incentivised towards LPG vehicles.
Q. 4. How is the infrastructure developing?
Ans. Currently there are more than 1,200 LPG refuelling stations
in the UK, and this number is constantly increasing - however depot
based fleets can take advantage of LPG immediately by installing
their own tank on-site.
Q. 5. What about the cost?
Ans. Autogas retails at around half the price per litre of unleaded
petrol and diesel. In practice this means that an Autogas vehicle
is about 40% cheaper to run than a conventional fuelled equivalent,
so depending on your mileage, the payback period of the Autogas
conversion (currently around £1600) could be less than 2 years.
Q. 6. What happens if an Autogas vehicle is involved in
Ans. All LPG tanks are rigorously tested and all are considerably
stronger than conventional fuel tanks. The UK has stringent safety
standards for Autogas vehicles and by selecting a reputable equipment
manufacturer and/or converter approved by the LPGA you are assured
peace of mind.
Q. 7. How much cleaner is Autogas than petrol?
Ans. Carbon dioxide is widely regarded as a main contributor to
the greenhouse effect, which is making our planet warmer. Autogas
reduces CO2 emissions from vehicles previously powered by petrol
by 15%. Autogas also emits 97% less Benzene than unleaded petrol.
Q. 8. How much cleaner is Autogas than diesel?
Ans. The black smoke that we see coming from diesel vehicles cause
over 20,000 premature deaths a year. By replacing a diesel engine
with an Autogas equivalent, over 90% less of this particulate matter
would be emitted.
Q. 9. If I convert my vehicles to Calor Autogas, can I
still drive on petrol?
Ans. Yes, and with bi-fuel you'll almost double your range. The
petrol tank still remains in the car and the driver can switch from
gas to petrol, or vice-versa.
Q. 10. Can LPG damage my engine?
Ans. No. In fact, LPG is a cleaner burning fuel engine, so life
is extended and less maintenance is required.
Q. 11. Will converting affect the performance?
Ans. There is very little difference in performance - however,
with a liquid injection system, performance can be increased by
5%. Some drivers find increased drivability and for anyone used
to driving on diesel, there's obviously a significant reduction
Q. 12. How much space does the tank take up?
Ans. For a range of about 300 miles most tanks take up less space
than a spare wheel.