Valvetronic

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Valvetronic in the BMW N52 engine

Valvetronic ( proper spelling : VALVETRONIC ) is a brand of BMW AG and the BMW name for a variable valve control of gasoline engines . It was first used in the 1.8-l and 2.0-l four-cylinder engines ( BMW N42 ) of the 316/318 Compact of the E46 series , available from 2001 .

The valves are operated with roller rocker arms via intermediate levers from the overhead camshaft. The intermediate lever is arranged vertically next to the camshaft and is supported at the upper end on an electrically adjustable eccentric. At the lower end it has a control cam with which the valve is operated via the rocker arm. Depending on the position of the eccentric, another part of the control cam comes into contact with the rocker arm. It is flat at first and becomes steeper towards the end. As a result, the eccentric position acts on the maximum valve lift. The Valvetronic can regulate the valve stroke between 0.25 mm and 9.8 mm within 300 ms. To do this, an electric motor from VDO adjusts the eccentric shaft . In addition to the valve lift control, an adjustment is in the fitted with valvetronic motors timing during charge exchange means camshaft adjustment employed by BMW VANOS mentioned.

With the variable valve lift, the intake volume can be regulated so that the throttle valve is no longer required during normal operation. The throttle valve is only used in special operating conditions, such as emergency operation.

Effects

By the throttle-free load control are pumping losses drastically reduced, also the higher inflow results in better mixing of the fuel-air mixture in the cylinder . This means that fuel consumption is around 10% (BMW data) lower than with conventional engines.

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  • Patent DE4223172 : cylinder head with rocker arms supported on an eccentric shaft. Registered on July 15, 1992 , published on August 19, 1993 , applicant: Bayerische Motoren Werke AG , inventor: Harald Unger. Or file reference DE: P 42 23 172.8 - patents and utility models of the German Patent and Trademark Office (DPMA).
  • Harald Unger: VALVETRONIC. The contribution of the valve train to the reduction of CO 2 emissions from the gasoline engine (=  Die Bibliothek der Technik . Volume 263 ). Verlag modern industry / Süddeutscher Verlag onpact GmbH, Landsberg am Lech 2004, ISBN 3-478-93308-0 .
  • Harald Unger: Constructions and investigations into the mechanical fully variable valve train . Dissertation, Techn. Univ. Munich 1997, DNB  951631675 ( gbv.de [PDF; 568 kB ; accessed on April 26, 2016] table of contents).
  • Karl-Heinz Dietsche, Thomas Jäger, Robert Bosch GmbH: Automotive pocket book. 25th edition, Friedr. Vieweg & Sohn Verlag, Wiesbaden, 2003, ISBN 3-528-23876-3

Web links

See also

Individual evidence

  1. ↑ Information on the Valvetronic brand  in the register of the German Patent and Trademark Office (DPMA)