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Natural gas systems: useful information

Find out everything there is to know about LPG and natural gas systems for cars: start saving and cutting pollution right away!

  • What is LPG?

    LPG stands for Liquid Petroleum Gas. It is a by-product of the refining of crude oil. LPG is a gas at atmospheric pressure and normal ambient temperatures, but it can be liquefied when higher pressure is applied and/or when the temperature is reduced. The LPG used in vehicles is a blend of propane and butane gases with chemical and physical properties that help vehicle performance in terms of power, versatility and engine functioning. The products of its combustion are carbon and nitrogen oxides and unburnt hydrocarbons, in smaller quantities than produced by petrol and diesel-fuelled vehicles, while aromatic hydrocarbons, sulphur dioxide and particulates are absent. The energy content of LPG is 10,000 kcal/kg, while that of petrol is 10,300 kcal/kg.
  • What is Natural Gas?

    Natural Gas (CH4) is the most ecological fuel of all, and one of the most abundant in nature. It is not obtained through a refinement process, but is an ecological fuel ready to use right from the source. Natural Gas contains no impurities, sulphur, lead compounds or aromatic hydrocarbons, so it produces only very low levels of polluting emissions, with no odour, particulate matter or combustion residues. The chemical composition of Natural Gas produces much less CO2 than other fuels and reduces ozone formation in the atmosphere. The intrinsic properties of Natural Gas make it suitable for use in vehicles with no need for additives that may be harmful to human health. Also, it contains more energy than any other fuel (natural gas = 11,600 kcal/kg; petrol = 10,300 kcal/kg; diesel =10,200 kcal/kg). Another important benefit is that Natural Gas is much easier and more economical to transport than other fuels, because after the initial cost of building a gas pipeline, it is very inexpensive to transport. Unlike other fuels, Natural Gas does not need to be transported in tanker trucks, which produce polluting emissions and contribute to traffic congestion, and therefore it helps reduce accident risk and pollution by heavy vehicle traffic. The Natural Gas pipeline grid is underground, so it does not affect the landscape in the places it passes through.
  • Is it true that LPG-powered vehicles pollute less than petrol-powered ones?

    Yes, it's true. With LPG, carbon dioxide (CO2) emissions are reduced by about 10%, while emissions of carbon monoxide (CO), nitrogen oxides (NOx) and unburnt hydrocarbons (HC) remain largely unchanged, depending on the type of vehicle and on the fuel system installed. LPG fuelled vehicles produce practically no PM 10, one of the principal causes of atmospheric pollution in city centres. LPG fuelling significantly reduces components of exhaust gases for which the law does not yet set any limits, such as, for example, sulphur dioxide (SO2), benzene (C6H6), formaldehyde (HCHO) and PAH (polycyclic aromatic hydrocarbons), highly aggressive carcinogenic substances ("unregulated" pollutants). Using LPG in place of petrol or diesel also reduces the potential for formation of “summer smog”, photochemical smog causing ozone (O3) production.
  • Is it true that Natural Gas-powered vehicles pollute less than petrol-powered ones?

    Yes, it's true. With Natural Gas, CO2 emissions are reduced by about 20%, while emissions of carbon monoxide (CO), nitrogen oxides (NOx) and unburnt hydrocarbons (HC) remain largely unchanged, depending on the type of vehicle and on the fuel system installed. Natural Gas fuelled vehicles do not produce PM 10, one of the principal causes of atmospheric pollution in city centres. Natural Gas fuelling significantly reduces components of exhaust gases for which the law does not yet set any limits, such as, for example, sulphur dioxide (SO2), benzene (C6H6), formaldehyde (HCHO) and PAH (polycyclic aromatic hydrocarbons), highly aggressive carcinogenic substances ("unregulated" pollutants). Using Natural Gas in place of petrol or diesel also reduces the potential for formation of “summer smog”, photochemical smog causing ozone (O3) production.
  • What are the main pollutants emitted by engines that are harmful to health?

    Engines emit different types of pollutants, depending on the engine type and the fuel used. The main ones include carbon monoxide (CO), nitrogen oxides (NOx) unburnt hydrocarbons (HC), particulate matter (PM10), carbon dioxide (CO2), benzene (C6H6), aldehydes such as formaldehyde (HCHO) and polycyclic aromatic hydrocarbons (PAH), and sulphur compounds such as sulphur dioxide (SO2) and sulphur trioxide (SO3).
  • Is there any specific legislation regulating vehicle emission levels?

    Yes, in Europe the reference legislation is Directive 70/220/EEC (as amended and updated by subsequent directives, most recently by 2003/76/EC). According to this Directive, only some of the exhaust substances emitted are subject to restrictions (maximum emission levels in grams per km). "Regulated" pollutants are: carbon monoxide (CO), nitrogen oxides (NOx), unburned hydrocarbons (HC) and particulate matter (PM). Carbon dioxide (CO2) is "under surveillance" but not "regulated" (the emission level must be measured and reported on the vehicle registration certificate, but a limit has not been set).
    • Environmental benefits related to LPG (3.04)
    • Environmental benefits related to Natural Gas (3.05)
    • Gas-fuelled cars and no-traffic days
  • LPG/Petrol savings: is it true that you can save up to 50% with an LPG-powered car compared to a petrol-powered one?

    Yes, it's true. The running costs for an LPG-powered vehicle are significantly lower than those for a petrol-fuelled one.
  • NATURAL GAS/Petrol savings: is it true that you can save up to 70% with a Natural Gas-powered car compared to a petrol-powered one?

    Yes, it's true. The running costs for a Natural Gas-powered vehicle are significantly lower than those for a petrol-fuelled one.
  • No-traffic days and alternating licence plates on city roads: is it true that in the event of such traffic restrictions, gas-fuelled vehicles can travel freely?

    Generally speaking, yes. However, in the case of no-traffic days or alternating licence plates on the roads, it is advisable to check the issuing order. In almost all cities that impose such traffic restrictions, LPG and Natural Gas fuelled vehicles are recognised as ecological and can travel freely.
  • Which legislation establishes the limit values for ambient air quality according to which restrictions are applied to the use of motor vehicles?

    Decree no. 60 dated 2 April 2002, transposing:
    • Directive 1999/30/EC on ambient air quality limit values (micrograms per m3) for sulphur dioxide (SO2), nitrogen dioxide, nitrogen oxides (NOx), particulate matter (PM) and lead (Pb)
    • Directive 2000/69/EC on ambient air quality limit values for benzene (C6H6) and carbon monoxide (CO).
    Restrictions on the use of motor vehicles are adopted with discretion by individual regions and municipalities.
  • What kind of tank is installed with a Natural Gas system?

    A Natural Gas fuelling system involves the use of cylindrical tanks of differing capacity, diameter, weight, etc.
  • Where is it installed?

    The cylindrical tanks are housed in the boot of the vehicle or outside the vehicle, complying with safety distances.
  • Does the installation of Natural Gas tanks require changes to be made to specific car parts, such as the suspensions?

    No, this is not necessary.
  • Does installation reduce space?

    This depends on the gas tank system installed.
  • Does installation involve the loss of a passenger seat?

    The weight of the Natural Gas system is calculated as part of the total load that can be transported by the vehicle (people + luggage). Therefore, the driver must take into account the weight of the system installed when determining the maximum load that can be transported.
  • Should the Natural Gas tank be serviced regularly?

    Yes, Natural Gas tanks must be tested every five years (calculated from the date stamped on the cylinders) by G.F.B.M. (Gestione Fondo Bombole Gas Naturale); testing is free. Users pay the cost of dismantling and reassembling the tanks. This operation is performed to check the efficiency and condition of the tanks in order to ensure fully safe use of Natural Gas systems on vehicles (Law no. 145 dated 7 June 1990, Presidential Decree n. 404 dated 9 November 1991).
  • What kind of tank is installed with an LPG system?

    An LPG fuelling system involves the use of two types of tank: cylindrical or doughnut shaped. These two types of tanks are available with different capacity, diameter, weight, etc. When a cylindrical tank is housed in the boot of the car, the load capacity reduces according to its size. Housing a doughnut shaped tank in the place of the spare tyre, instead, safeguards the space available.
  • Where is it installed?

    The cylindrical tank is normally positioned in the boot; the doughnut shaped tank, instead, is normally housed in the place of the spare tyre. Both types can be positioned on the outside of the vehicle in compliance with safety distances.
  • Does installation reduce space?

    When a cylindrical tank is housed in the boot of the car, the load capacity reduces according to the tank's capacity. Housing a doughnut shaped tank in the place of the spare tyre, instead, safeguards the space available. The spare tyre can be stored in a special bag, or replaced by a tyre repair kit.
  • Does installation involve the loss of a passenger seat?

    The weight of the LPG system is calculated as part of the total load that can be transported by the vehicle (people + luggage). Therefore, the driver must take into account the weight of the system installed when determining the maximum load that can be transported.
  • Should the LPG tank be serviced regularly?

    No, LPG tanks do not need to be serviced. LPG tanks must be replaced after 10 years of use. In this regard, it should be noted that the tenth year of use should be understood as commencing:
    • on the date the system was tested, if its installation occurred after the vehicle was first registered;
    • on the date the vehicle was first registered, if it is certified as having been set up with an LPG system right from the start.
  • What cars can be converted to gas?

    All petrol-fuelled cars, vehicles with carburettor, injection fuelled vehicles and injection fuelled vehicles with catalytic mufflers can be converted to run on gas, whether with an indirect or direct injection system. When having an LPG or Natural Gas system installed on a vehicle, it is advisable to check with a specialised workshop as to which type of system should be installed on the specific vehicle model.
  • Can diesel-fuelled cars can be converted to gas?

    Yes, the innovative LANDIRENZO DUAL FUEL injection system makes it possible to convert diesel engines into engines that can work with a mixture of diesel and natural gas. This renews diesel engines with new technology that saves money, improves autonomy and cuts polluting emissions significantly. This sophisticated technology may be applied to medium-to-light commercial vehicles with standard conversion kits and to heavy vehicles with special conversion kits.
  • Is it possible or advisable to convert utility vehicles?

    Modern gas fuel supply systems do not result in significant power loss compared to running on petrol, and therefore it is possible to install LPG and CNG systems even on utility vehicles.
  • Is it possible to transfer a system from one car to another?

    It is technically possible (if the engine characteristics are similar and allow it), but it is not economically viable as the cost savings resulting from not having to purchase new components are cancelled by the double cost of labour.
  • What condition must the car be in to be able to be converted to gas and function optimally?

    A vehicle that runs well on petrol and has been kept in good general condition will run well on gas. In order to install an LPG or CNG system on a vehicle, this must be in good general condition; in particular, the ignition system (coils, spark plug wires, spark plugs), the air filter, the lambda probe, the catalyst and the valves must be in good condition.
  • How long does it take to complete installation of a gas system?

    Installation of an LPG or CNG system normally takes just a few days in a specialised workshop.
  • Is it still possible to run the car on petrol after installing a gas system?

    Installation of an LPG or CNG system will not affect the vehicle’s ability to run on petrol. The driver may decide which fuel to use by simply pressing a changeover button on the dashboard. Today’s gas systems are easy to use as they ensure the vehicle always starts up running on petrol and automatically switches to gas after about 15 to 60 seconds, when optimal running parameters have been reached. Installation of a gas system practically doubles the vehicle’s autonomy, which can now count on two fuel supplies.
  • Is it preferable to run a new car in before converting it to gas?

    No. There are no specific contraindications. However, it is worth checking the gas system once the car has been run in.
  • Does Landi Renzo have a network of qualified and authorized installers?

    Over the years, we have developed a qualified network of Dealers, Authorized Workshops and GAS Specialists, with staff trained and continuously updated on new products and installation techniques by means of technical courses and direct technical assistance, ensuring constant support for the entire network. Moreover, Landi Renzo's Italian Network of Workshops and Dealers has also been certified under ISO 9001 since 2006, and there are plans to extend this certification to the Group's networks in other countries. View the Landi Renzo Network of Workshops
  • Why does it cost more to convert to Natural Gas than to LPG?

    The higher cost is primarily due to the cost of the high-pressure natural gas tank. As Natural Gas is under considerably higher pressure than LPG (about 200 bar as compared to 15 bar), the safety standards to be met are much higher.
  • Are gas systems safe?

    Yes, they are safe. Products installed in vehicles in specialised workshops are approved by the Transport Ministry on the basis of European standards. All Landi Renzo products are also tested one by one on the basis of our quality system, which obtained ISO 9001 Certification in 1996 and ISO TS 16949 Certification in 2001, the Quality System specific to the automotive sector involving the application of extremely strict quality standards.
  • Are LPG tanks safe?

    LPG tanks have always been designed and constructed taking into account the chemical-physical characteristics of the fuel. LPG tanks are built using 3.5mm steel sheets, heat-treated to avoid cracking in case of deformation (caused for example by an accident). The standards governing the construction of the various components are very severe. The tests and trials for tanks and pipes are performed at a pressure of 45 bar, although normally the operating pressure in vehicles never exceeds 20 bar.
  • What is the reference standard for LPG tanks and what security systems are required?

    LPG tanks are regulated by UN/ECE Regulation no. 67/01, which sets forth the special devices required to ensure maximum safety in every situation (fire, accident, parking in an underground garage, exposure to excessive heat by radiation, etc.). In particular, there is a special multivalve that encloses the following safety systems:
    1. A "normally closed" solenoid valve (i.e. closed when it is not powered) interrupts the outgoing flow of gas from the LPG tank when the "key" is not inserted in the panel. This is also an important safety feature since, in the event of an accident, it closes as soon as the engine switches off, even if the "panel" remains on.
    2. A fill limit device interrupts LPG supply during filling when 80% of the tank’s volume is full. This device, required by law, prevents pressure in the tank from increasing excessively due to external causes, such as overheating (an increase in temperature expands gas; when the gas is enclosed in a sealed environment such as a tank, this expansion creates an increase in internal pressure).
    3. A pressure release valve prevents excess pressure from building up inside the tank; in the event of pressure over 27 bar, LPG is released externally in a gradual, controlled manner. This permits restoration of regular working pressure in the LPG tank and eliminates the risk of overpressure.
    4. A temperature relief valve releases gas externally in a gradual, controlled manner when the temperature exceeds 120°.
  • Are Natural Gas tanks safe?

    Natural Gas tanks offer guaranteed safety as they are all subjected to strict tests, both for approval and throughout their lifespan. The particular strength required to endure testing pressures of 300 bar and operating pressures of 220 bar means the cylinders are extremely resistant to impact. Use of thoroughly tested, dependable components, the adoption during installation of all measures aimed at preventing gas leaks in the event of an anomaly in operation, and the intrinsic features of natural gas (high ignition temperature, possibility of ignition only within a certain interval of mixing with air) are all factors that play an important role in ensuring safety. As Natural Gas is lighter than air, in the event of a leak it will not stagnate but be dispersed in the atmosphere without accumulating along the ground. Response has been positive all over the world. Tests conducted on Natural Gas cylinders by the world’s most important safety organisations (Bureau Veritas in Norway, EPA in the US, etc.) have yielded very successful results, guaranteeing the utmost dependability for this type of tank. A report by Norway’s Bureau Veritas states that the risks linked with use of Natural Gas fuelled vehicles are no greater than those associated with diesel-fuelled vehicles.
  • What are the standards applicable to Natural Gas tanks?

    Natural Gas tanks are regulated by UN/ECE Regulation R110.
  • In the event of an accident, what happens with an LPG system?

    Leakage of gas from an LPG system is much less likely than leakage of petrol. Fire tests have demonstrated that in the event of a fire, flame volume is much smaller than in the case of petrol leakage, which tends to spread over the ground around the vehicle. Dozens of crash and fire tests have been conducted, in collaboration with fire fighters, using the most sophisticated equipment to check the efficiency and safety of valves and tanks.
  • In the event of an accident, what happens with a Natural Gas system?

    Dozens of crash and fire tests have been conducted, in collaboration with fire fighters, using the most sophisticated equipment to check the efficiency and safety of Natural Gas systems and tanks. Natural Gas has the highest flash point of any fuel. It ignites at a temperature of 595°C, twice as high as that of liquid fuels, and combustion concentration (5%) is much higher than that of petrol (1%) and diesel (0.5%); these factors significantly reduce fire risk. Natural Gas has a lower density and specific weight than air, so if it should leak for any reason it will tend to become volatile, rising into the atmosphere rather than stagnating at ground level and accumulating in hazardous concentrations.
  • How can I detect a gas leak?

    Both LPG and Natural Gas are odorized so that you can detect any leaks.
  • Do gas-fuelled cars require special maintenance?

    Like any mechanical component subject to wear, natural gas systems need regular maintenance every 20,000 km (which may be performed during regular vehicle maintenance sessions), during which the correct functioning of the various components will be checked. Special attention should be directed to the gas filter (which may need replacing) and the ignition system, which must be kept in perfect condition.
  • What is the difference in performance between an LPG-fuelled vehicle and one run on petrol?

    An LPG fuelling system causes the following variations: A maximum power loss of about 2-3%, which basically preserves the vehicle's performance.
  • What is the difference in performance between a Natural Gas -fuelled vehicle and one run on petrol?

    A Natural Gas fuelling system causes the following variations: A maximum power loss of only 10% of maximum torque, resulting at most in a 5-10% drop in speed.
  • What is the autonomy of a car powered by LPG?

    To calculate the autonomy of a car powered by LPG, you must take into account several factors. Consider 80% of the total tank capacity (for safety reasons, the tank is 80% filled) Consider then that the performance of an LPG-run car is 85% of that of one run on petrol. For example, the autonomy of a car, equipped with a 48l LPG tank, which travels 10 km with 1l of petrol, is calculated as follows: Actual litres of LPG in the tank: 48 * 0.80 = 38.4 l of LPG Performance in km/l of LPG: 10 * 0.85 = 8.5 km/l of GPL Autonomy running on LPG: 38.4 * 8.5 = 326 km Note that the autonomy of the petrol tank remains unchanged and, therefore, the car's autonomy increases significantly as the car can run on both fuels.
  • What is the autonomy of a car powered by Natural Gas?

    To calculate the autonomy of a car powered by Natural Gas, take into account the following example. A car with a 100-litre cylinder, filled with natural gas at 220 bar, has an autonomy in km approximately equal to the consumption of 30 litres of petrol. Note that the autonomy of the petrol tank remains unchanged and, therefore, the car's autonomy increases significantly as the car can run on both fuels.
  • How do you calculate the conversion from petrol to LPG in km/l?

    LPG is purchased in litres. In general, the km/l performance of an LPG-fuelled vehicle corresponds roughly to 85% of the performance of the same vehicle powered by petrol. If a car runs 10 km on 1 litre of petrol, it will run 8.5 km (= 10 x 0.85) on 1 litre of LPG.
  • How do you calculate the conversion from petrol to Natural Gas in km/l?

    Natural Gas is purchased in kilograms. In general, a vehicle fuelled with 1kg of Natural Gas covers the same number of kilometres as it would cover with 1.7 litres of petrol (1kg CNG = 1.7 l petrol).
  • How is an LPG tank filled?

    The LPG tank is filled by fastening the pump nozzle to the vehicle's gas filler. This filler differs from country to country (coupling connection in Italy, bayonet in Holland, ACME in the United States, Canada, Germany, Great Britain, Ireland, Austria, Belgium). In a modern service station, filling the LPG tank takes the same amount of time as filling the petrol tank. For safety reasons, the multivalve on the tank means that it can only be filled to 80% capacity.
  • How is a Natural Gas tank filled?

    Natural Gas vehicles are filled by connecting the pump hose with the filling valve on the vehicle, which is normally inside the engine compartment or near the petrol tank filler. There are different types of fillers in different countries. In a modern service station with weighted pumps, refuelling takes 6 to 8 minutes with 80 - 100 litre cylinders.
  • Can gas-powered cars be parked in a garage?

    Natural Gas-fuelled vehicles can be parked in any kind of garage (underground included). As for parking LPG powered cars, modern vehicles equipped with a system installed after January 2001, and therefore in compliance with Regulations R67/01, can be parked in any kind of garage, but only as low as the first underground level in the event of underground car parks. LPG fuelled vehicles that do not meet UN/ECE Regulation no. 67/01 must continue to refer to the Decree dated 1 February 1986, meaning that they can only park above ground in parking lots not connected with underground levels, unless the owner decides to adapt the installation to European standards (adaptation is quick and inexpensive).
  • Can gas-powered cars be boarded on a ferry or ship?

    There is no in-force legislation in this regard; regulation is left to the discretion of the shipping companies. According to established practice, it is advisable to inform the shipping company when travelling with a gas-powered vehicle, both at the time of buying the ticket and when boarding. In any case, we recommend you always check with the specific shipping company.
  • Is it safe to drive through tunnels and galleries with gas-powered cars?

    Yes, there are no restrictions of any kind.
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