What is LPG?
LPG (Liquefied Petroleum Gas) is a mixture of hydrocarbon gases, primarily propane and butane, which in normal conditions are gases but at pressures higher than 2 bars become liquid. LPG is obtained from the extraction of petroleum, around 2% of the extracted product, and 5% from the extraction of natural gas. It is also a by-product of crude oil refining. The use of LPG as a fuel dates back to 1800 and thanks to the considerable technological progress made in conversion kits, LPG is today an ideal alternative for those wanting to save money and respect the environment when driving. LPG vehicle emissions in fact pollute less than petrol ones and the former do not produce particulate. In addition to this, burning LPG does not produce carbon residues. This is why engine oil in LPG vehicles remains clear and its properties unaltered, even after many thousands of kilometres and this helps to reduce wear and tear of the engine’s mechanical parts.
Are LPG systems safe?
Absolutely. Systems installed in Romania in present meet the European UN ECE 67 R-01 regulation, which guarantees very high safety standards, based on extremely stringent international specifications and tests (crash tests, vehicle fire, etc.). In addition to having all their parts tested and approved according to this standard, LPG conversion kits are fitted with various safety devices:
• a tank multivalve that automatically blocks refuelling at 80% to allow expansion of the gas should the temperature rise;
• lock-off valves that shut off gas flow at the tank outlet and at the pressure reducer inlet in the engine housing and a tank approved to extremely stringent standards.
Modern LPG systems can therefore be considered absolutely safe and LPG systems are today used as original equipment or recommended for installation also by various automobile manufacturers.
What benefits does LPG conversion offer?
Considerable savings in the price of fuel (over 50% compared to petrol). When calculating savings, you must consider the advantage offered by the price (50% to 60% lower) of LPG together with around 10-12% lower mileage. Greater autonomy, generally 400 to 500 km, due to the addition of the LPG fuel tank. Lower emissions, normally guaranteeing that LPG vehicles can be used even when roads are closed to certain kind of vehicles or even-odd number plate measures are enforced. LPG combustion does not produce carbon residues (which cause engine oil to turn black). For this reason the engine oil in LPG vehicles remains clear and its properties unaltered, even after many thousands of kilometres and this helps to improve performance and reduce engine wear and tear.
Which cars can be converted to LPG?
LPG conversion is suitable for petrol cars with carburettor, turbo, injection, catalytic and Euro-6 approved engines.
LPG conversion kits also exist for the most common direct injection engines.
Is an LPG car less powerful?
With LPG modern sequential injection systems, loss of power stands at around 2-5%, generally lower than the power absorbed, for example, when the air-conditioning is switched on and with negligible effects on performance.
Can I still drive on petrol if I install an LPG system?
After installation of the LPG system, the vehicle becomes Bi-fuel, in other words, it can run either on gas or petrol. In this way the original autonomy of the vehicle actually increases, depending on the size of the gas tank installed.
Does an LPG-fuelled car consume more?
Due to the different chemical and physical properties of gas compared to petrol, there is generally an increase in fuel consumption of 10%-12%, which will also depend on the kind of system installed. This increased consumption is due to the lower calorie potential of LPG. However, the lower price of LPG and its lower environmental impact make it an economical (savings of approximately 50%) and eco-friendly choice.
Is an LPG system difficult to use?
Everything is automatic with LPG modern injection systems. All the driver needs to do is fill up with gas, push the fuel-switch and… start saving!
What emissions legislation must LPG vehicles comply with?
By law, after LPG conversion, the vehicle must comply with the same reference law applied to the original petrol type approval. LPG modern sequential systems are approved to EURO 6 and are, therefore, compatible with vehicles compliant with the most recent EU legislation.
How safe are LPG tanks?
LPG tanks are extremely safe, approved and tested according to extremely stringent standards, they are more resistant to blows and fire than normal petrol tanks fitted to cars. All LPG tanks fitted in Romania are compliant with the UN ECE 67 R-01 regulation which requires, for example, that every tank be tested to a pressure of 30 bars, almost three times the normal operating pressure.
LPG tanks are built from very thick high-resistance steel, heat treated to deform in the case of blows without cracking and tested during approval to a pressure of 67.5 bars. Furthermore, in compliance with the UN ECE 67 R-01 regulation, the multivalve fitted to the tank has a pressure relief valve to prevent overpressure and a heat valve to release the gas in a situation of excessive heat. As shown by many “bonfire tests” (tests that simulate the car catching fire due to external causes), the result of these technologies is an extremely safe product.
How does a modern LPG system work?
The most recent technological evolution of LPG conversion systems is represented by sequential multi point fuel injection systems. This LPG timed sequential injection system, whereby the gas is injected into each cylinder by an injector synchronised with the cylinder’s stroke in the same way as for petrol engines, is designed for 2 to 8-cylinder engines including turbo or Valvetronic, versions. It is also suitable for all Start & Stop system vehicles.
Thanks to this technology, the LPG system complies with the most recent legislation up to EURO 6. All the system components have been designed and tested to guarantee maximum performance and reliability. The main components of this system are:
• Filling connector: Connector with standard european attachment (used in most European countries apart from Germany, Netherlands, Luxembourg, United Kingdom and Ireland) fitted with a check valve, for filling the tank. It can be installed on the bodywork or under the petrol flap if there is enough space.
• Tank: This is filled with liquid LPG at the fuel pump at a pressure of around 15 bars. The tank is in arc welded high-resistance steel, heat treated to prevent cracks if it should be deformed by a blow. Today tanks are usually toroidal in shape so that they fit into the space designed to hold the spare wheel, but they can also be cylindrical.
• Multivalve: A multipurpose valve fitted onto the tank that allows it to be filled with gas via the connector and automatically blocks refuelling at 80%. It powers the refuelling circuit and measures the gas level with dedicated sensors. The multivalve is fitted with a lock-off valve for when the engine is switched off and heat and pressure relief valves. The multivalve zone is sealed from the car interiors with its own box or lid.
• Reducer: This vaporises the gas from its liquid state and reduces its pressure, stabilising it at the correct level for fuelling the common rail injection. It has a safety lock-off valve that closes all LPG flows when the engine is off.
• Gas Filter: This guarantees that the gas flow to the common rail injection and therefore to the cylinders is free from impurities and oil residues. LPG system is also fitted with temperature, gas pressure and engine load sensors for optimum system function.
• Common Rail gas injection: Controlled by the system injection electronic control unit (ECU), injectors synchronised with the engine inject the correct quantity of gas into each cylinder.
• GAS/Petrol fuel-switch: This allows the driver to switch from gas to petrol and vice versa and shows the gas tank level on an LED display. In normal conditions, the vehicle starts on petrol and then automatically switches over to LPG, undetected by the driver, when the circuit reaches the required working temperature (about 35°C). Should the LPG run out, the system automatically switches back to petrol and an alarm alerts the driver.
• Electronic Control Unit (ECU): TThe control unit interfaces with the original petrol control unit and via signals received from the system sensors controls the gas injectors, calculating times and quantities of gas to inject. The ECU is calibrated on installation to meet the vehicle’s specific characteristics and uses auto-adaptive programmes to adjust the working parameters according to variations in conditions of use and engine wear and tear.
What maintenance does an LPG system need?
To guarantee correct long-term working, the system is checked periodically (e.g. filter replacement) according to a programmed maintenance plan, at every 10.000 km. This maintenance is therefore usually carried out by a mechanic during the vehicle’s normal services.
Can the LPG tank be installed underneath the car chassis?
This kind of installation is possible when the minimum legal distances between the vehicle and the ground (250 mm when the car is empty) are respected. The tank must also be protected by a sheet metal covering, with a minimum distance from the ground of 200 mm when the car is empty.
Why are LPG cars more ecological?
Polluting emissions are significantly lower with LPG with 30% less CO, 20% HC and, relatively, also CO2. Gas cars do not produce particulate, in particular the PM10 that are critical for urban pollution.
Can LPG cars be parked in underground car parks?
LPG vehicles fitted with safety devices compliant with the UN ECE 67 R-01 regulation and therefore all vehicles converted since 01/01/2001, can be parked in underground garages down to the first level. Cars converted before this date and therefore still compliant with the previous legislation, can only be parked above ground.
If I use LPG do I also have to fill up with petrol?
Given that the car usually starts on petrol before automatically switching over to gas, it is a good idea to always have a certain amount of petrol in your tank. For some makes of car, petrol in the tank also serves to protect the petrol pump that would deteriorate prematurely if the car were run on empty.
