Autoportal has repeatedly covered the intricacies of LPG equipment for cars. However, judging by the number of letters and comments, there remains a significant number of skeptics. In this material, we tried to address all the most "acute" points that concern car owners. After all, more and more Ukrainians are installing LPG systems on their cars.
Is LPG not equally "beneficial" for all cars?
The myth that gas leads to car breakdowns dates back to the USSR era. Back then, many drivers were engaged in stealing fuel from service vehicles. When the party ordered part of the transport to be converted to gas (for economy and environmental reasons), ordinary citizens lost an additional source of income. Draining gasoline is not a problem, but with gas, that won't work. The theft schemes often involved fleet managers (recall the legendary phrase: "and for this I allowed my own shed to be mutilated"). Therefore, both they and the drivers united their efforts to discredit the technology of gasifying vehicles. Drivers wrote fictitious reports about frequent breakdowns, fleet managers passed them up the chain, etc. The result - LPG ruins the internal combustion engine.
If you study the statistics and experience of other countries, you can draw completely different, unexpected conclusions. For example, not everyone knows (and wants to believe) that when using gas, there is less wear in components and assemblies, and no carbon deposits in the combustion chambers.
Very often, from pseudo-specialists, we hear that LPG is not suitable for certain types of engines. In particular, gas is literally contraindicated for Subaru boxer engines. But we can tell a real-life story that happened to our colleague while in the Netherlands. He visited a Subaru dealership in Amsterdam, where an interesting conversation took place between him and the salesman:
- Tell me, could I buy a Forester with gas equipment?
- Of course, it's right in front of you. In fact, all the cars you see are gasified.
- What? Even this sporty Impreza?
- Yes, of course. Who needs it without LPG. Without LPG, it's very expensive to drive.
- And won't that affect the engine's operation?
- It will, its mileage will be one and a half to two times longer. It all depends on your driving style.
Any skeptic can double-check this information about gasifying Subaru (and not only) in the Netherlands. Why do we have problems with LPG that the rest of the world doesn't know about? It's very simple. Gas has a higher octane number. Accordingly, the engine must operate with different ignition timing settings. You don't have to worry about the safety of any engine, including Subaru, if you install LPG at a certified station of the equipment manufacturer. It's another matter if it's done in a "garage" shop. They might install it correctly, but the adjustment - no. Then the result can be sad. Most often, prolonged operation with incorrect ignition timing leads to burnout of the exhaust valve in one or even several cylinders.
LPG generations. Their number and differences
First and second generations are systems designed for old carburetor and mono-injection engines. Their gas consumption is about 20% higher compared to gasoline. Considering them today is no longer relevant, as carburetor engines have been discontinued by almost all manufacturers. The first generation differs from the second in its ability to work with engines equipped with a catalytic converter.
Third generation can work with carburetor and mono-injection engines. The system delivers gas to the intake manifold very close to the intake valve of each cylinder. Between the nozzles installed in the intake manifold and the reducer, which handles excess pressure supply, there is a mechanical stepper doser that distributes proper portions of gas to the intake manifold.
The disadvantage of this generation is that LPG does not use the engine's electronic control unit and, accordingly, the algorithms by which the injection timing and the amount of required fuel are calculated. That is, all calculations are performed according to algorithms set by the LPG manufacturer. They can differ significantly from factory requirements and lead to incorrect engine operation.
Fourth generation has electromagnetic gas injectors that provide gas injection into each cylinder (that is, analogous to a gasoline system). Dosing and determining the injection phase is done by the standard vehicle controller.
The advantages of the fourth-generation LPG system are several. For example, automatic transition of the engine from gas to gasoline fuel. With proper LPG tuning, the driver practically does not notice the transition from gas to gasoline and back. The difference in gas consumption (compared to gasoline) does not exceed 10-20%.
Today, this is the most popular and profitable equipment for gasoline engines with distributed fuel injection.
Fifth generation is a "liquid phase distributed injection" system.
The difference from fourth-generation LPG is that the 5th generation injects gas into the cylinders in a liquid state. For this, the cylinder has a gas pump that ensures the passage of gas in the liquid phase from the cylinder (via the gas injector rails) and excess back into the cylinder.
The fuel maps and engine ECU are standard. Only minor changes may be made to adapt the gas system to the gasoline fuel map. The fifth generation uses additional injectors and a rail.
There is an opinion that with the fifth generation, it is possible to start the engine on gas, and consumption is identical to gasoline costs. But this is not entirely true, according to AUTOGAS CENTER:
"The system needs time to pump gas and remove air from the system, about 30-40 seconds (depending on how long the car has been parked). But still, this time is much less than warming up the engine in the 4th generation, and it does not depend on air temperature (winter-summer). Consumption - +10-20%, compared to driving on gasoline," specialist Pavel dispels the myths.
Sixth generation. Yes, it also already exists! In this case, the fuel rails, injectors, and the standard gasoline controller of the car remain original without any modifications.
There is practically only one drawback - sensitivity to gas purity. The cost can also be attributed to drawbacks, however, as is known, after mass production begins, the price may significantly decrease. Note that the installation of the 6th generation is only possible on engines with direct fuel injection.
Today, offers for installing 5th and 6th generation LPG in Ukraine already exist, although there are few of them. And this is logical - try finding quality gas here too...
Is the overpayment always justified?
The most common systems today are fourth generation. It's easiest to track the average cost of equipment and installation for them.
Note that the price difference (depending on the manufacturer) ranges within 5-10%. The main difference can accumulate due to the cost of installation and tuning. But! It is precisely the installation and tuning that will determine how well and long your engine will work...
The price of equipment directly depends on the number of cylinders in the engine. Since a separate injector is installed for each cylinder. It's quite logical that for a four-cylinder engine the price will be one, and for an eight-cylinder engine - another. In addition, the capabilities of the injectors play a role. The larger the cylinder volume, the larger the injector flow area should be. The price will also be higher.
Often you can hear, is it profitable to drive on gas? The answer is unequivocal, it's profitable. But how much, that's the second question. You can answer it yourself. To do this, you need to know the cost of LPG installation, the cost of gasoline and gas. A calculator won't hurt.
For example, let's calculate the payback of LPG for two different cars. The first has a four-cylinder engine with a volume of 1.6 L, and the second has 4.8 L and 8 cylinders. Average gasoline consumption in the first is 10 L/100 km, in the second 20 L/100 km. Installation cost is 8,500 UAH and 16,000 UAH, respectively. Gasoline price is 16.3 UAH, and gas - 8.9 UAH. We will consider that gas consumption may be about 10% higher than gasoline.
For 100 km of travel, a car with a 1.6 engine will spend 10 L of gasoline or 163 UAH, gas 11 L or 97.9 UAH, that is, the difference is 65.1 UAH. This is the amount you save. But you also need to recoup the installation cost. Divide 8,500 UAH by 65.1 UAH and multiply by 100 km. At these prices and with this fuel consumption, the installation will pay off in 13,000 km. Further mileage will save you 65 UAH every hundred kilometers.
Using the same scheme, we recalculate the car with a 4.8 L engine and get a difference in travel cost of 130.2 UAH, and LPG payback - in 12,288 km.
How much you drive directly affects the payback period in months, days, years.
What to do if there is increased consumption or uneven engine operation on gas?
You won't be able to determine how good LPG installers are "by eye." Ideally, they should have a certificate showing their level of professionalism and ability to install this equipment. Moreover, it's worth carefully studying who it was issued to. They might show you a certificate from another company, passing it off as their own.
It's good if the service is recommended by any of your acquaintances or friends. If they have no problems with LPG installed by a specific service, then you will most likely be satisfied with its services.
LPG installation location
Any gas cylinders have a solid margin of safety. At least, if compared to a fuel tank, this margin is more than tenfold. You can easily install a cylinder under the car's floor instead of the spare tire. For the overly cautious, it's enough to install additional protection, similar to those installed under the engine. This will be more than enough for peace of mind while driving. The probability of cylinder damage and car fire with gas is very low, but provided that the system is in good condition and all safety valves are operational. Therefore, you need to monitor the system and undergo scheduled maintenance.
One of the most common mistakes is filling the cylinder without a technical reserve of free space in cold weather. After warming up, the pressure rises to critical values, the cylinder depressurizes, and a subsequent explosion occurs. Therefore, never fill the cylinder completely. In addition, all cylinders have a maximum service life. After its expiration, they must undergo re-inspection. The gas pipeline system in the car must regularly undergo maintenance to detect leaks and carry out preventive measures.
If you look at recorded explosion cases, almost all of them occurred due to non-compliance with safety rules.
Next time, we will tell you whether it is possible (and necessary) to install LPG on small-displacement engines, how to equip home gas refueling stations, and what the real power loss is when installing LPG.
