Consequently, the piston head approaches the bottom dead center when the port is opened and the admission pressure is achieved.
An excessive admission clearance also causes backflow through the admission port when the piston leaves the bottom dead center.
The functional demonstrator of the DLR operates with a mass variable gas spring, in which an electromagnetic switching valve fills the chamber to the appropriate pressure in the bottom dead center
(BDC) of the gas spring.
For example, at top dead center on a crank pin there is very little cheek metal, almost none really, while at bottom dead center
, on the same pin, the heated area is virtually surrounded by a huge heat sink.
During the intake of the air-fuel mixture in the Quad-4, a piston moves through a full stroke and past bottom dead center
. The intake valve closes only when the piston has passed through a third of the compression stroke.