Comprehensive analysis of advantages disadvantages of car LPG and CNG vehicles: cost savings, convenience, maintenance schedule, engine wear, specific rules and constraints

In this time of expensive fuel, it advocates the desirability or not to switch to gas. Whether it's natural gas or LPG, the car is registered as a bi-fuel or is transformed as a result, the advantages are many: savings on supplies, lower emissions and the ability to circulate forever. What I am going to do is a list of the main concerns, even of the biggest fears that there may be dealing with such a choice.

I state that since there are no incentives to scrap and / or environmental incentives, and I say no no form of sponsorship was made to support the only alternative (and who knows for how long) to oil, and I'm not versed in issues type White Paper on Transport, Protocols on CO2 emissions, etc ...

The burning hotter and drier ruin valve seats and tested

It 'important to know that in the combustion of the air / gas mixture in the combustion chamber temperatures increase from 12 to 15 degrees. The gas is a gaseous fuel consequently has no action on the lubricant and coolant valves and valve seats.

In addition, there are no gas substances used in gasoline (benzene, toluene, etc ...) that washes up on the valves and valve seats, creating a layer of protection on the same cushion and help it to beat on the seats of the valves being closed, thereby mitigating the effect of "hammer".

This peculiarity makes that in gas operation every 40-50,000 Km, depending on the use of the car, there is a variation of the opening and closing of the exhaust valves to the detriment of the heat exchange in the combustion chamber. If the valves are not self-regulating, that is not automatically adapt to this variation, the car requires a maintenance recording valves to maintain the characteristics of drivability and reliability.

The maintenance varies according to the materials of construction of valves and valve seats.

1. If the car is equipped with a self-regulating valve requires no maintenance, and if the materials of construction of valves and valve seats are made of steel. The duration of the engine in gas mode is superior to petrol.

2. If equipped with valves to register and plate glass and steel building materials, require registration valves every 100/120.000 km depending on the use of the car.

3. If equipped with valves to register and plate glass and building materials not made of steel, valves require registration every 40-50,000 km depending on the use of the car.

The combustion clean and free of deposits makes the cylinders so smooth that the elastic bands can no longer be held by increasing the consumption of oil

It 's true but the increase of oil is irrelevant (certainly a minor inconvenience to the problem of some PAF or DPF filters in diesel engines)

The coils will break down more easily for the greater heat produced by the combustion gas

Depends on the car and the position of the coils, also in this case a car arranged to dual power certainly has a greater protection of the other.

Driving with the fuel tank below 1/4 you risk burning the fuel pump;

E 'enough to keep ¼ of fuel in the tank to be used, however, over the two months and replace it with fresh gasoline as green gasoline, if not used within this time decomposes and can cause damage to the fuel pump and the eletttroiniettori

Do not operate the engine with gas reserves of the petrol tank turned on because the fuel pump may deteriorate. Even the use of the car switched to the gas pump works to circulate the fuel injectors and let them cool.


Life of LPG-CNG injectors around 60000km - Turning much gas you encrust the petrol injectors

As mentioned below is always advisable to alternate a guide to LPG with a gasoline especially if you make long-distance paths for short-term this problem does not exist


Replacement Filter LPG-CNG every 20000km

The cost is really limited (simple operation and less than 25 €)


Efficiency of the motor indecent well as a decrease in gasoline yield than before installation, higher consumption than petrol

It is true, 10-20%, but today the delta petrol-LPG is about 90%

How to petrol operation is very important the perfect stoichiometric control of the air / gas mixture for low emissions, high performance, low power consumption and to avoid further increases in temperature in the combustion chamber and the exhaust circuit.

Under conditions of lean mixture (excess air) temperatures rise considerably.

Under conditions of rich mixture (excess gas) parts burned in the combustion chamber burn in the catalyst. Also in this case the temperature rises considerably and in both cases it will have to premature wear of the valves, valve seats and the catalyst


Parking is not always allowed in the garages underground

For cars powered by LPG, you can park in the floors above the ground and first floor of underground garages, even if organized on a more underground floors (as per regulation ECE / ONU 67-01)

The methane-powered cars - unlike other gases - can be parked anywhere without any structural limitation. In fact, the Decree of 1 February 1986 of the Ministry of the Interior provides, in paragraph 10.6, that "the parking of gas-powered automobiles with a density greater than air, is permitted only in floors above ground basement with non-communicating" . Since the methane gas has a lower density than air, the above provision therefore allows the parking of vehicles to methane everywhere.


Go and Rivai installer for the various calibrations and off lights motor fault;

Understood as to vehicles with different power.

All cars that meet the Euro 3 standards, EURO 4 and EURO 5 are equipped with a control system on system failure "EOBD".

This symbol indicates an on-board diagnostic system for emission control.

The system malfunction is indicated by a light amber:

The anomaly signal occurs in two ways:

1) light is on steady light: the motor control signals the presence of an error that does not lead to the deterioration of the catalyst.

In this case, you can continue to run their own vehicle but it should be checked as soon as the cause of the anomaly.

2) warning light to light: the motor control signals the presence of "misfire or misfire" that lead to damage to the catalyst.

In this case it is not recommended operation on gas.


Replacing LPG cylinder after 10 years - For the CNG cylinders shall be reviewed every 5 years if they are approved under the national legislation, if every 4 to the European standard (R110 UN / ECE) and replaced, respectively, after 40 or 20 years

And 'the law that compels us (and rightly so), however it comes to longer than the average life of a car


The savings is relative because if you make short trips will be a long way since gasoline to go to the gas temperature must reach at least 25 ° (then winter ....)

It does not seem a major inconvenience, it is' advisable to alternate the use of the two fuels especially at high speeds and in conditions of maximum effort engine (eg on the highway on a long ride switch gas to petrol is very important to avoid wear valves, valve seats and catalyst.

In urban route instead you can use the car exclusively gas as driving conditions do not lead to increases in temperature in the combustion chamber such as to cause premature wear.





Translated via software



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