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After a little over a decade, the transition to downsizing engines seems complete. Almost all new generations of units are already turbocharged. During this time, naturally aspirated engines gradually faded into the background.

Downsizing, a popular term among the general public, has recently become less and less common in car brand press releases and in the media. Maybe it's because there is nothing to cut. Has the switch to smaller turbo engines already taken place? And how quickly the last decade passed, at the beginning of which VW introduced the first generation of its 1.4 TwinCharger, which became one of the founders of this direction. Naturally aspirated gasoline engines are quite rare today and can be found in some exotic sports models or base units of major car companies, as well as in still entrenched idealists such as Mazda and somewhat. Toyota... There are other exceptions of course, like the many cheaper Chinese cars that are likely to run on these cars for a long time to come. After years of wandering, periods of revitalization and dwindling interest, forced turbocharging has finally found its place in the sun. From walking in a car in the 70s with a pioneering effort BMW, Porsche and SaabDuring the exotic Japanese adventures of the 80s and the powerful sports versions of the 90s, the turbocharger found its use as a technical component of modern internal combustion engines.

There is no way back

There is logic in this transition. The smaller turbocharger has several advantages over the larger naturally aspirated engine. To begin with, reducing internal friction due to a smaller working volume and number of cylinders. In addition, a decrease in pumping losses due to the fact that the turbine creates pressure in the intake manifold, which helps filling and even at this time "presses" on the piston. The variable valve timing capabilities help keep the intake and exhaust valves open at the same time, and the cylinder is blown out by the exhaust gases, and direct injection works great here, providing internal cooling of the combustion chamber where the working pressure is higher. atmospheric cars. The higher pressure makes the combustion process more efficient due to the closer proximity of the molecules to each other. BMW demonstrates the fact that with state-of-the-art fuel injection and precision electronics, designers will be able to return to water injection and additional in-cylinder cooling capabilities. Since this solution is used at high loads and provides a significant reduction in the propensity to knock, it becomes possible to increase the geometric compression ratio and improve operating efficiency over the entire operating range. Audi shows how the efficiency of a turbocharged gasoline engine can be improved using the Miller cycle variant in its new 2.0 TFSI. Thanks to the same electronics, direct fuel injection, twin-jet turbochargers and the ability to integrate exhaust pipes into the gas cooling head, the turbomachines have much more favorable and functional characteristics for everyday life than their corresponding naturally aspirated gasoline units. The already iconic 1.0 EcoBoost from Ford reaches 170 Nm of torque at 1400 rpm. It is expected that in the second generation the consumption of the small engine will be further reduced - this time on the go some of the cylinders need to be switched off (in this case, understand one) that VW has pioneered again with the 1.4 TSI ACT. On the diesel front, business is still in full swing, with production units with three turbochargers and experimental models with an optional electric compressor already available.

Text: Georgy Kolev

Read more about the topic in the new issue of auto motor und sport magazine.

2020-08-30

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