1-   What is the difference between LPG and Natural Gas?

LPG is a liquid gas petroleum-derived (actually it is a gas mixture which includes mainly propane and butane) contents into appropriate pressure vessels (a ca 6-8 bar).

Natural Gas (or CNG, compressed natural gas) on the other hand, it is a natural gas that is contained in specific high-pressure containers, the cylinders (a ca 200 bar).

2-   Is it true that LPG and Natural Gas are good for the environment?

Yes. Compared with diesel, they don’t emit dust particulates. If the level of emissions of an engine is 100, regarding the carbon dioxide, in the case of LPG drops at 90 and to 75 in the case of Natural Gas.

As regard to the polluting agent, excluding the hydrocarbons (unchanged emissions between gasoline, LPG and Natural Gas) the benzene emissions, the nitrogen oxides and the carbon oxides appear to be always lower than those of the gasoline, especially when old vehicles petrol-fueled are transformed. The emissions of the dangerous benzene are zero in the case of vehicles powered by Natural Gas.

Out of curiosity: since the molecule of Natural Gas is stable, the catalyst struggles to purify the hydrocarbons (for this reason the cars powered by Natural Gas carried out directly by the producers have often a more expensive catalyst, since richer of noble metals).

3-   Can circulate the gas-fueled vehicles in case of roadblock for environmental reasons?

The emissions of a gas-fueled engine are much lower than that of the equivalent petrol or diesel-fueled engine. For this reason, generally, the gas-fueled cars shall be exempt from the roadblock (also because there are very few compared to the car fleet). However it depends on the choices made by the City Council who schedules the roadblock.

4-   Is it true that a vehicle consumes less of the corresponding vehicle petrol or diesel-fueled?

It depends. A LPG-fueled car consumes at least 20% more than one petrol-fueled (but also 30% more it is supposed). On the other hand, a Natural Gas-fueled car consumes (in kg/100 km of gas) as a diesel-fueled vehicle (in l/100 km) and even less. Generally we can say that no fuel is more convenient than the Natural Gas.

5-   Is it hard to convert a vehicle into a gas-fueled one?

The transformation into gas requires the add to the vehicle of an installation ad hoc from a specialized garage. In general this shall include the stop for the vehicle check of a day. However, the law considers the installation of a LPG or Natural Gas implant as a modification to the characteristics of the vehicle, consequently it requires the updating of the Registration Certificate.

This means an examination, so-called testing, at the offices of the DVM (Provincial Motor Vehicle) where it is located the specialized garage that carries out the change. This prolong the stop of the stop for the vehicle check for a few days. Passed the examination and the test, the office of the DVM (Provincial Motor Vehicle) updates the Registration Certificate through the release of a self-adhesive coupon to be shown on it or though the release of a duplicate of the Registration Certificate.

Warning! The  vehicle has to be tested at the competent DMV for the updating of the Registration Certificate also when:

àThe previous fuel installation is removed and the initial petrol-fueled is restored;

àmodifications occur to the constituents installed in the case of systems already approved (for example, the substitution of the expired LPG tank).

Warning! The substitution (carried out free of charge) of the cylinders of Natural Gas with other similar, in the occasion of the expiry, doesn’t need the updating of the Registration Certificate.

6-   Are there incentives for the purchase or for the transformation of vehicles gas-fired?

It depends. The law provides different amounts depending on whether you purchase a new vehicle gas-fired approved or a new vehicle transformed into gas-powered, or in the case in which you transform into gas-powered a vehicle already on the road.

7-   Is it convenient  turning into gas your own vehicle?

It depends. LPG and Natural Gas are cheaper than petrol and diesel. However, the transformation costs, as well as it costs more than the corresponding petrol version, a new vehicle gas-fired approved (in general the maintenance of a gas-powered vehicle, it’s more expensive).

It’s impossible to predict the price trend of LPG and Natural Gas, for this reason it’s hard to say which is the most convenient. Prices will drop in the case of incentives to buy or to transform the vehicle.

8-   In the event of an accident, the gas-fueled system is dangerous?

No. The LPG and Natural Gas tanks are regulated by the legislation ECE/ONU 67/01 which provides for arrangements to ensure safety in every situation (fire, accident, exposure to heat).

9-   Is it true that the Natural Gas cylinders and the LPG tanks must be revised periodically?

Yes. The Natural Gas cylinders must be revised every five years if they meet the national standards or every four years if they are in line with the Regulation ECE/ONU n.110.

In the first instance the upper limit of use is 40 years from the date of building, in the second case, on the other hand, they can’t be utilized for longer than 20 years (or for a shorter period if required by the constructor) and after that period they must be set up for the scrapping.

The law provides exceptional checks when the cylinder has been in an accident, it has been in a fire or it was reinstalled after have been dismounted by another vehicle.

Regarding the LPG tanks, these should be tested periodically every 10 years.

10-Is it true that the gas engine has under-perform?

Yes, but far less as it used to be. Actually the modern gas installations shall take the sequential injection with an injector for every cylinder, who place the gas as close as possible to the intake valve.

The LPG performances almost match these of the petrol-fueled system and there’s no risk of accidental breakups.

11-Which risks imply, for the engine, the transformation to gas-fired system?

The modern LPG and Natural Gas installations achieved such a level of sophistication that almost exceeded the electronic “crisis of rejections” which occurred not too long ago. Rather to get worried, are the mechanical problems. Some engines don’t like the gas high temperature of combustion and the feature of gas to burn so cleanly, so dry and without the lubricity.

Those who have problems are especially the premises of the valves that rots and lose thickness.

12-Is it true that setting up the gas system the guarantee decade?

For a new vehicle, covered by legal guarantee for two years, the installation of a gas system means the loss of the right to the repair only for the components interested to the dual-fuel.

Instead, to ensure those involved in the transformation are the installer and the builder: it’s up to them the coverage on the remaining parts and on the two-years guarantee on the system and on the editing carried out.

13-Is it true that  the gas-powered vehicles can’t be parked in the ground?

In general, it’s not true. In the case of LPG, the law establish that the establishments meeting the norms ECE/ONU 67/01 (all the LPG systems must be necessarily equipped with this security system since 1st January 2001) can be parked until the first basement of the garages.

14-The gas supply can be done on your own?

No. However in the case of LPG, the refueling is quick and similar to that carried out with the traditional petrol and diesel providers, so much so that in some countries (not in Italy), self-service is allowed.

Instead in the case of the Natural Gas, since it is a high-pressure gas, the refueling is more complicated and longer, for this reason it isn’t allowed the self-service.

15-Is it true that the gas providers are only a few and are badly distributed on the national territory?

Definitely the gas providers aren’t spread like the petrol and diesel ones. However in certain regions, especially for the LPG the net has reached appropriate levels at the new request.

16-After all, it’s better the LPG or the Natural Gas?

Utilize the Natural Gas is advantageous economically even than the already convenient LPG, thanks to the higher performance of this gas and despite the higher cost of the installation and the largest volume and weight of the cylinders.

However, in support of the LPG there is the wider dissemination of the providers, the lightness of the tank (that doesn’t affect in a meaningful way the weight distribution of the car). Against, there are the limitations in the parking.


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