Boost pressure

from Wikipedia, the free encyclopedia

The boost pressure is the air pressure in the intake line of an internal combustion engine, either absolute or relative to the surrounding atmospheric pressure.

Supercharged engines

In the case of charged internal combustion engines , the charging pressure or boost is the pressure relative to the surrounding atmospheric pressure. It is also called “pre-compression” and is recorded by a measuring instrument at a point determined for the respective engine type and, in some vehicles, displayed inside or outside the instrument cluster . The boost pressure can be regulated for engines with the appropriate boost technology.

In piston engines, turbocharging the engine can increase torque and power. A higher boost pressure causes a higher power output at full load , which is of course also a greater load on the engine at this moment . With most series engines with turbo - or compressor charging, the manufacturers therefore compromise and choose a not too high boost pressure in order not to restrict the running performance of the engine too much, and thus to be able to give acceptable guarantees . In racing , and especially in vehicle tuning , however, higher boost pressures are chosen in order to achieve an even higher power output. The mileage of the engine is only considered secondary. Normal petrol engines with pre-compression often work with boost pressures below one bar , diesel and more powerful and / or smaller ( downsizing ) petrol engines with boost pressures of 1 bar and more (for example VW Golf VI R: 1.2 bar). Seat used in 2009 for its diesel racing engine in the WTCC , however, much higher boost pressures from 2.5 to 2.9 bar, because diesels are much more dependent on the boost pressure, as a foreign ignition / petrol, to achieve similar performance improvements there. In the 1980s, boost pressures over 5 bar were also used in Formula 1 in the qualifying rounds, with which the 1.5 liter engine delivered up to 1050 kW (= 1430 hp).

Naturally aspirated engines

In non-supercharged engines, the boost pressure (in this context manifold pressure , abbreviated MAP ) is the absolute pressure in the intake tract. It is basically less than (or equal to) atmospheric pressure. The measurement and display is mainly used in aircraft engines with controllable pitch propellers in order to be able to adjust the power, since this is no longer directly reflected in the speed due to the propeller adjustment.

literature

  • Gert Hack Iris Langkabel: Turbo and compressor motors. 1st edition, Motorbuch Verlag, Stuttgart 1999, ISBN 3-613-01950-7

Individual evidence

  1. ↑ Lutz Algermissel: Sporty compact: Most powerful Golf of all time only has four cylinders. In: welt.de . September 16, 2009, accessed October 7, 2018 .
  2. ↑ http://www.motorsport-total.com/wtcc/news/2009/05/Neue_Regelung_Ladedruck-Erhoehung_fuer_SEAT_09052209.html
  3. ↑ Michael Schmidt: BMW four-cylinder turbo: Bayern power with 1,430 hp. February 18, 2019, accessed April 3, 2020 .