Cam groove control
The curved groove is a valve control mechanism for controlling the discharge valve of a four-stroke - gasoline engine .
Development of the cam groove control
In August 1883, Daimler received parts from the Kurtz bell foundry for an engine which, according to the foundry's documents and records, had a cylinder diameter of 42 millimeters and a stroke of 72 millimeters. Maybach and Daimler experimented with it for about five months until the engine worked reliably. New on this prototype were the valve control via a cam and the glow tube ignition . Gottlieb Daimler submitted a patent specification for this invention on "regulating the speed of the engine by controlling the exhaust valve".
The principle of the patent was based on the control of the exhaust valve in the cylinder head by a rod. At the foot of this rod sits a bolt with a sliding block that runs in the groove of a control disc at the end of the crankshaft. The groove milled in the disc consists of two concentric circles that are crossed together at one point. The sliding block changes from the inner to the outer circle and vice versa with every rotation. The valve is kept closed for one turn via the control rod and is then open for one turn. The outer circle of the control groove does not extend over the full circumference, it merges into the intersection, the inner circle goes through so that the sliding block can also run through the inner circle and the valve remains closed. This is brought about by flyweights which, at speeds above 600 rpm, twist a tongue located in the branch of the inner groove. This limits the speed. This control was used on the machine called the grandfather clock motor . For this invention, Daimler received Imperial Patent No. 34926.
The spring-loaded inlet valve was located in the piston and was controlled by a stop in the crankcase. During the intake stroke, air was initially drawn in through the exhaust valve until the fresh mixture flowed over from the crankcase shortly before bottom dead center.
In 1892 a camshaft was used for valve control for the first time in the construction of a two-cylinder engine instead of the cam groove control.
The original engine was destroyed by a major fire in 1903 at the DMG plant in Cannstatt, so that it could later only be reconstructed from the inventor's records and from the foundry's books.
As is well known, camshaft technology has established itself as valve control over time, while cam groove control has faded into the background.
literature
- The great automotive history of Mercedes-Benz. United Soft Media Verlag GmbH, Munich 2002
- Wolfgang Roediger: A hundred years of the automobile - reports and findings. Urania-Verlag, Leipzig / Jena / Berlin 1988, 2nd edition, ISBN 3-332-00035-7 .
- German patent specification No. 34926, issued April 3, 1885, accessible via http://depatisnet.dpma.de/
- German patent specification No. 28243, issued December 22, 1883, accessible via http://depatisnet.dpma.de/
- German Patent No. 28022, issued December 16, 1883, accessible via http://depatisnet.dpma.de/
- Reinhard Seiffert: The Gottlieb Daimler era: New perspectives on the early history of the automobile and its technology. Vieweg, 2009
- Friedrich Sass: History of the German internal combustion engine construction: From 1860 to 1918. Springer, 1962
Individual evidence
- ↑ Daimler: Engines, Carburettors, Radiators and Gears (1883–1901) ( Memento of the original from May 20, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Daimler Internet portal, "Press kit: Mercedes-Benz" section, November 20, 2007.
