Position of orange cradle of the blue crank shaft determines compression ratio of violet piston cylinder. It gives different volumes of the combustion chamber. There is an offset between the blue crank shaft and the cradle axes.
The position is controlled by yellow crank shaft connected to the cradle by pink conrod. A cylinder and rack-gear drive for turning the yellow crank shaft are not shown.
The video shows the shifting process from high compression ratio to low one and then back to high one.
Disadvantage: the output crankshaft axis position is variable.
This working principle is taken from Envera VCR 1.0 car engine.
Inventor files of this video:
[ Ссылка ]
The static compression ratio is calculated by the following formula:
CR = (Vp + Vc) / Vc
Where
Vp: volume created by piston motion
Vp = (π /4).b.b.s
b: cylinder bore (diameter)
s: piston stroke length
Vc: clearance volume (volume of the combustion chamber (including head gasket)). This is the minimum volume of the space at the end of the compression stroke, i.e. when the piston reaches top dead center.
In this mechanism Vc is adjusted to get various CR.
STEP files of this video:
[ Ссылка ]
Inventor files:
[ Ссылка ]
