How does CNG affect the engine of a car?

8 myths about HBO. They are debunked by the experts at the wheel.

Gas in a car prolongs the life of the engine, significantly reduces the cost of operation and is not dangerous at all. These statements are true only partially.

The country is full of gas

Automotive gas fuel comes in two varieties: liquefied petroleum gas (LPG) and compressed natural gas (CNG), also known as compressed natural gas (CNG). Compressed natural gas (methane) in Russia is really full, and it is relatively cheap. But there is much less liquefied gas (a mixture of propane and butane).

In general, filling stations in the country with propane-butane enough, but with compressed gas the situation is worse. There are only eleven methane-fueled filling stations even for the multi-million city of Moscow. However, gasification of vehicles is clearly zoned by climate zones. The more south, the more gas stations with compressed and liquefied gas. And vice versa, one cannot find a gas car in the North.

Gas is twice as cheap

Liquefied gas has always cost motorists about half as much as high-octane gasoline. And a kilometer driven on compressed gas is almost three times cheaper! And, as with gasoline and diesel fuel, gas prices differ from region to region..

To calculate the net benefit of switching to gas, you need to consider the additional costs as well. The initial cost of the set of GTB for LPG plus its installation and mandatory registration will not cost less than 40,000 rubles. Installation to run on methane – almost twice as expensive, primarily because of the expensive cylinders to withstand high pressure. In addition, HBO requires periodic maintenance and pressure testing of cylinders, which also increases costs.

Operating consumption of gas is about 10% higher than that of gasoline. Besides frequent “overruns” in search of gas-filling station are inevitable. Therefore, Only those with average annual runs over 30,000 kilometers will save money.. And if you drive a little bit and not every day – gas is not about you. And sell the “gas” car will not be easy: usually mileage in these cars is much higher, not everyone is willing to put up with holding space in the trunk of the cylinder and to take on the additional burden of service and repair of gas turbine.

Kilometer traveled by a car on propane-butane gas is almost twice cheaper than for gasoline. For methane it is three times cheaper.

You still need gasoline.

It’s true – it’s almost impossible to run a cold engine on gas. Saturated vapor pressure, which affects starting properties, is much lower in gas than in gasoline. And gas gearbox diaphragms lose elasticity in severe cold, which reduces their service life. That is why when starting the equipment is switched to “petrol” mode, and only then, after warming up, are switched back to “gas” mode. By the way, modern GTB systems determine by themselves when to switch from one fuel to another. In addition, gasoline is needed in case you run out of gas and there is no filling station nearby.

Simple starter, schematic

Gas doesn’t smell

Neither natural gas nor petroleum gas is odorless. But since gas leaks are extremely dangerous, so-called odorants are added, which have a pungent smell. If you feel a characteristic odor – urgently to the service department to look for a leak and adjust the equipmentCars with removed catalytic converter will smell – the usual bouquet of harmful gases will have notes of ethylmercaptan, that very odorant.

That’s how much gas a 60-liter cylinder can hold

No, not 60, but about 50. The reason is simple: it’s a safety measure to compensate for gas expansion when heated – so the cylinder doesn’t burst from the inside. For this purpose, a multi-valve is installed on the cylinder that prevents filling more than 85 per cent.

Gas prolongs life of the engine

It does not, but most of fears about gas being harmful are exaggerated. Gas is slightly better than gasoline with regard to the engine piston group and slightly more aggressive to the exhaust valves. Gas burns slower, the afterburning occurs when the valves are open, which heats up more.

Gas is cleaner than petrol: it has no sulfur, which is the main catalyst in the formation of so-called high-temperature deposits (sludge and carbon deposits). That is why the oil service life is longer when the engine is running on gas. There is a fly in the ointment, though: the combustion of gas produces more water. When the engine is not warmed up and the crankcase ventilation system is defective, it condenses, watering the oil, thereby reducing its characteristics.

Elements of the system of feeding liquefied petroleum gas fourth generation: 1 – filter vapor phase, 2 – absolute pressure sensor, 3 – electronic control unit, 4 – harness control, 5 – switch modes “gas / gasoline”, 6 – Multivalve, 7 – toroidal cylinder, 8 – Filling valve, 9 – Reducer, 10 – gas injectors.

Elements of the system of feeding liquefied petroleum gas fourth generation: 1 – filter vapor phase, 2 – absolute pressure sensor, 3 – electronic control unit, 4 – harness control, 5 – switch modes “gas / gasoline”, 6 – Multivalve, 7 – toroidal cylinder, 8 – Filling valve, 9 – Reducer, 10 – gas injectors.

12 to 5 volt converter for charging phones from the cigarette lighter

Any car can be converted to natural gas

You can equip anything with gas equipment, but in some cases it makes no sense. For example, it is not reasonable for small cars: their fuel consumption is small and there is no place to store the tank. It is not worth converting new cars: You can lose the warranty on the engine due to the use of non-recommended fuel, on the body (drilled, overloaded) and on the electrics, which were tampered with.

Diesel cars are also best left untouched. The gas mixture requires an ignition dose of diesel to ignite itself – such systems are complicated and expensive. Do not switch to gas, if you often use the entire usable volume of the cabin and the trunk – the equipment will eat a lot of space, as well as reduce the possibility of transforming the interior.

Gas is more dangerous than gasoline

This is somewhat true. Improper installation can cause a leak, and it is more difficult to detect, and gas ignites more readily than gasoline. In this case Particularly dangerous is liquefied gas, which is heavier than air – it does not rise up, and accumulates under the car, in pits and basements of garages.

The pressure gauge at the gas station shows that the gas is pumped into the cylinder at a pressure of as much as 16 bar. But when the cutoff valve kicks in, 85 percent of the gas will remain in the liquid phase and 15 percent in the vapor phase. Therefore, pressure inside the cylinder drops from 16 to 8 bar, which is not such a frightening indicator. Truck wheels, for example, are inflated to comparable values.


It is often said that compressed gas is not intended for private consumers at all. This statement is partly true: the number of methane filling stations is small. However, today natural gas is getting the green light: those who have decided to install compressed natural gas are promised financial support. Gazprom has presented a program for developing the gas filling network – the number of gas stations has increased several times in the last year and by the end of 2020 there will be at least five hundred of them.

Diagram of the converter DC/DC 12-5V

Manufacturers will follow the infrastructure. For example, AVTOVAZ is already mass-producing methane-powered versions of the Vesta and Largus. This is convenient and advantageous for those who need a gas-powered car – they won’t need any modifications or re-registrations. The lineup of many foreign brands also have gas-powered models. If there is demand, they will bring them. Therefore, it turns out that the future is more for methane than for propane-butane.

Converting your car to gas is justified only when you are going to drive it for a long time and a lot. And it doesn’t make sense for the average motorist to convert their car to gas.

The impact of gas on the engine of a car with HBO

Gas and engine

With the constant rise in price of petroleum fuel, every motorist thinks about how to drive a car more economically. One of the alternatives to gasoline and diesel fuel is gas, namely propane-butane mixture or methane.

Despite all the advantages of running a car on gas, there is a strong opinion among drivers that you should not operate a car on gas, because it has a negative impact on its propulsion system. Therefore, in this article we will consider how gas affects the engine of the car.

Gas for the engine from the positive side

Let us list the main advantages of using gas fuel for the operation of the internal combustion engine (taking into account the correct adjustment and operation of the machine, as well as the timely replacement of components):

  • The resource of the engine running on gas and gasoline is different in favor of gas fuel. On average, it increases engine life by 30 percent.
  • Gas-air mixture fills the cylinder unlike gasoline more evenly, and as a result there is a smoother and more complete combustion of the mixture, which leads to lower detonation and reduces the load on the details of the cylinder piston group;
  • The gas does not contain heavy impurities (tars, sulfur compounds, paraffin and lead), and therefore no abrasive substances are formed that affect component wear;
  • Combustion temperature is higher than that of gasoline and diesel fuel, which leads to the removal of carbon deposits;
  • Unlike gasoline, gas does not wash oil off the cylinder walls and does not liquefy oil;
  • Minimum negative impact on the oxygen sensor and catalytic converter, because gas has no heavy impurities in its composition.
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Is gas harmful for the engine?

Opponents of the use of gas equipment claim that the impact of gas has a negative impact on the engine of the car. Piston rings, valves and fuel nozzles can fail sooner, as they are not designed to work in high temperature regime. This statement is only partially true.

Indeed, these parts can fail prematurely. However, it is connected not exactly with a temperature mode, but with the wrong adjustment of the distributive mechanism and improper operation of the car.

Let’s consider, what harm does GBO have on engine:

  1. A slight decrease in the dynamics of the car is a consequence of slow combustion of gas fuel.
  2. SBS is demanding to the quality of the air mixture, so the air filter will have to be changed a little more often.
  3. If you notice that the gas consumption has increased, check the air filter, most likely it needs to be replaced.
  4. Sometimes when you switch to gas there is a back pop, but the gas equipment has nothing to do with it. It has to do with the malfunction of the internal combustion engine:
  • improper adjustment of ignition, including timing phases;
  • malfunctions of ignition system parts.

Engine drying on gas: fiction or reality

Many drivers are afraid to install gas equipment, faced with the opinion of burnt out valves after installing gas equipment, because “gas dries the engine. But the drying of the engine occurs – as a result of improper selection of equipment, due to lack of experience of the installers. In addition, some “experts” believe that there is no need to tune anything, there is an autocalibration for that. As a result of such awry experts become problems with the engine and disappointment in auto owners of gas fuel. We wrote about how to find a competent master here.

Why are the valves on gas burning? The Real Causes

Valve burnout

The main reason why intake and exhaust valves burn on gas is the quality of the gas-air mixture.

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A rich mixture has a positive effect on the engine – it helps clean combustion chamber parts from carbon deposits and unburned fuel. But it leads to increased gas consumption, premature catalytic converter failure and possible burnout of the manifold or exhaust system parts.

If you adjust the GTB properly, there is no adverse effect on the catalytic converter.

Poor mixture increases the risk of valve sagging and premature valve failure due to high combustion temperatures. Also a lean mixture leads to early replacement of spark plugs. Therefore, you should not tune the system for the sake of saving gas.

Blown valves

The mixture quality on the 1st and 2nd generations was very difficult to adjust, the 4th generation allows a more precise adjustment.

In addition, the valves are burned because of a loose fit to the seat as a result of improperly adjusted clearance. On cars, where the gap is adjusted by hydro-compensators, there is no such problem, as it is set automatically.

How to avoid harmful influence of HBO on the internal combustion engine

Having considered the positive and negative effects of gas as a fuel, it is possible to preserve the resource and avoid harm to the car engine, but with the proper adjustment and implementation of the following recommendations:

    It is necessary to carry out in the service, where trained and qualified specialists work;
  1. Carefully select the equipment for your vehicle;
  2. Timely conduct work related to engine maintenance and replacement of consumables;
  3. Control proper ignition setting and gas mixture quality;
  4. Periodically check the tightness of gas equipment connections.

To sum it up

In general, the use of gas for the ICE is preferable, and the engine is killed by improper adjustment. If during the installation of the gas equipment all the work was carried out qualitatively, the adjustment of the equipment is made correctly, and the operation of the car is carried out in accordance with the recommendations, you can not worry about the condition of the engine.

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