The company Infiniti announced that it will display at the Paris Motor Show the unique variable displacement engine VC-T with variable compression ratio, and just a few weeks ago we looked at some parts of Japan firsthand. In a nutshell -- it is a revolution. And here’s why.

Engineering prophets who promised to bury the piston engine and create a more efficient internal combustion engine, there were hundreds, but all of them as heretics were burned at the stake of scientific and technical evolution. One of the clearest examples of this -- rotary vane motor e-mobile with a flow rate of 3.5 liters of fuel per 100 kilometers, the creators of which were quietly forgotten even before the death of the project for obvious reasons -- it was not possible to build a working sample of this engine.

The main real competitor of the piston internal combustion engine promised to be the Wankel rotary engine, which went into production in the sixties.

The new engine developed by Infiniti or, to be precise, the entire Nissan corporation -- the Variable Compression Engine (VC-T) -- has the usual pistons and connecting rods, but it is markedly different from any other engine. And its main difference is that it can be in the process of changing the compression ratio.

The degree of compression is called the volume ratio of the combustion chamber when the piston is at bottom dead center to the volume when the piston is at top dead center. Simply put, it is the degree of compression piston air-fuel mixture. The greater the compression, the mixture expands relatively more compressed volume during the combustion, and the greater the pressure on the piston, the capacity and overall efficiency is increased. In general, the dream of every automotive engineer.

The problem is that with a high degree of compression and high load, the fuel does not begin to burn, and it explodes. This effect is called a detonation and is not good either in terms of power, either in terms of reliability. Engineers have to look for compromise and choose the degree of compression, which eliminates the detonation.

The VC-T engine allows you to change the compression ratio in steps at different speeds, and load on the engine, always staying on the verge of maximum efficiency and avoiding detonation.

According to the engineers, the VC-T engine should be 27 percent more economical than the current atmospheric V6 Series VQ, which it will eventually replace. Hence, passport consumption in the combined cycle is within 7 liters.

And yet, to evaluate the real contribution of the new technologies in the economy is not yet possible, since the VC-T and VQ engines are too different. Volume, presence boost, number of cylinders – everything is different. Therefore, the real benefits of the Japanese development have yet to be understood, but as with any revolution, it is interesting in itself.