CNG (compressed natural gas) is the methane, the hydrocarbon of which the mix called natural gas is almost entirely composed by.
CNG
CNG is an excellent fuel for controlled ignition engines, allowing to achieve great performances, low consumptions, very low polluting emissions and almost complete absence of carbon residuals into the engine. Thanks to its molecular structure, it can increase the energetic efficiency while reducing consumptions very much.
In italy 3,420,776 vehicles supplied by alternative fuels and propulsions are travelling, of which 926.704 (2,41) have petrol-CNG bi-fuel engine. All bi-fuel vehicles are 8,88% of national car fleet (information provided by consorzio ecogas study centre)
In case of petrol and gas oil vehicles, it is widely accepted that the main polluting elements are carbon oxides, nitrogen oxides and particulates (microscopic particles containing a chemical elements mix – just for diesel oil engine), which still are a big problem to resolve.
With CNG systems, CO2 (carbon dioxide) emissions are reduced by 20% and particulate matter (PM10), main cause of air pollution, is zero.
CNG supplied by filling stations is measured in kilogrammes. 1 kg of CNG (year 2018) costs approximately 0,99 euro/kg and corresponds to about 1,5 litres of petrol. In short, the use of CNG offers considerable economic advantages.
The total capacity (in litres) of cylinders installed divided by four gives with good approximation the equivalent CNG cubic metres contained into the tank.
For example, a 80 lt cylinder contains about 20 cubic meters of CNG.
Assuming to average 14 km to the CNG cubic metre (roughly equivalent to 12,5 km per petrol litre), the range should be at around 280 km.
Link to calculate the savings.
The difference between two different fillings depends on both driving style and quantity of fuel supplied. The engine efficiency and the atmospheric conditions (air pressure and humidity) influence the engine performances too.
Being CNG not liquid, the fuel quantity supplied is not only a matter of tank volume (capacity of cylinders in litres) but also of pressure and temperature achieved at the end of filling; so, fuel quantity supplied can slightly change every time (the same happens in case of liquid fuels, but in a less sensible way). The quantity supplied also depends on gas features (see next question).
It is quite normal that gas network supplies CNG with different composition and origin, even to the same filling station at different times. This can result in difference on kg supplied and amount to be paid. It should be said, however, that the heavier the gas, the bigger the energy content – and the longer the range.
A CNG vehicle is filled by connecting the suitable nozzle to the car filling valve, generally situated into the engine compartment or next to the petrol filler.
In a modern filling station supplying CNG by weight, the refuelling can take 2 or 3 minutes on a mid-size vehicle (80 – 100 lt cylinder).
Distribution network has today about 1.200 CNG stations in italy, constantly growing, and approximately 3.700 CNG stations in 29 european countries.
For further information, download the APP BRC (link to the APP)
CNG system does not damage the right engine operation at all, on the contrary it extends its life.
BRC gas equipment provides approved cng supply systems consistent with most of todays’ car engines on the market, so that you can convert to CNG almost all petrol vehicles (both the carburettor and the injection or supercharged ones) without incurring any technical problem. Ask anyway a BRC installer for checking in details your engine and providing more specific information.
It depends on the kind of system and the installer labour organisation. On average, the conversion takes a few days.
In case of the most advanced systems (BRC sequent sequential multipoint gas injection), the difference in performances driving the car is almost imperceptible.
More than one only CNG cylinder can be installed on a car. So, by optimising the choice in accordance with the car boot, we can save space considerably without reducing the CNG total capacity too much.
CNG systems do not need any specific maintenance. Following the instructions indicated by the use and maintenance booklet of the system is suggested. In italy, a specific tag required by the law (CNG cylinders fund committee) shows safety and validity information about cylinders installed on the car, necessary to refuel. CNG cylinders must be replaced after 4 or 5 years from its final test according to the compliant regulation.
Please check the related laws in force in your country.
In italy, CNG vehicles are not subject to any restriction concerning underground parking.
Thanks to the very low polluting emissions, CNG vehicles can move freely into the historical centres during traffic restriction periods too, except for different indications.
The CNG conversion cost depends on many factors, such as the vehicle original supply (injection, direct injection), the kind of equipment installed (traditional, timed injection), the number of cylinders and so on. Ask BRC gas service installers for the most suitable system for your car.
Periodically, some economic measures are aimed at facilitating the CNG vehicles users. Visit the following links for more detailed information about incentives currently in force
In one of about 600 installers who are members of the BRC Gas service network (link to the site www.brcgasservice.it)
