What will happen if... install LPG on a diesel

Installing gas-balloon equipment on gasoline engines is a common practice that has been known for a long time. However, more and more drivers are wondering whether it is possible to install LPG on a diesel engine.

How it was before

The key problem in converting a diesel engine to gas is the principle of ignition of the fuel mixture. Diesel fuel self-ignites from compression, and this is the basis of the operation of such engines. Gas, like gasoline, does not ignite from pressure. It would seem like a dead end, but a solution was found back in Soviet times.

Instructions for KAMAZ vehicles with gas-balloon equipment

Specialists came up with a scheme in which the engine runs on gas, and it is ignited by a small portion of diesel fuel. Such systems were first installed on KAMAZ trucks, right on the assembly line.

Scheme of factory LPG and its connection with the high-pressure fuel pump on the KAMAZ engine

How it works:

Gas enters the cylinders in a volume of 70-80% of the norm, and at the right moment the injector injects an ignition dose of diesel fuel — the remaining 20-30%. Thanks to the high octane number of gas (100-110 units), the engine runs smoothly, without detonation. Practice has shown: the resource of such "gas-diesel" engines before overhaul increases by 1.5-2 times. They operate noticeably quieter and smoother.

Fuel savings reached 30-40%, if additional maintenance is taken into account. But after the collapse of the USSR, the developments were curtailed, considering the project unprofitable. The not-so-best quality of domestic components also played a role. Still, it is worth admitting: apart from KAMAZ trucks with factory LPG, other vehicles remained only on paper.

Where LPG for diesel cars is sought

AutoPortal found out: in Ukraine and Russia, only a few companies undertake the installation of LPG on diesel vehicles. We contacted all of them to find out prices for such equipment for passenger cars. In the list of vehicles suitable for conversion, the most compact was the "Valdai" (also known as "Gazelle"). Further — only trucks.

Almost all masters use their own developments based on second-generation LPG components. However, in Dnipropetrovsk, there was a company that creates systems based on the fourth generation. The design is assembled from proven parts familiar from gasoline versions: reducer, injectors, cylinders, pipelines, crankshaft sensors, camshaft sensors, gas pedal and temperature sensors.

But some things had to be developed independently. Wiring and connectors are of Ukrainian production. The gas-diesel control unit and its software are also a local development. A complete set with installation will cost about 25,000 UAH.

Is it worth it? Let's calculate using the example of the "Valdai", which spends about 14 l/100 km in the city. After installing LPG (propane-butane), fuel is consumed in a 2:3 ratio — two parts diesel, three parts gas.

Here are the numbers:

With savings of 28.90 UAH per 100 km, to recoup the installation, you will have to drive 86,505 km. Only after that will real benefit begin. Whether it is worth it depends on how and where the vehicle is used. It seems that converting diesel to gas makes sense mainly on heavy trucks with powerful engines. But on small-displacement cars, especially passenger cars, such an undertaking is hardly justified. Do not forget about the range — with LPG it increases, which means stops at gas stations will become less frequent.