Actuator working principle
Hydraulics has the natural cabability to deploy concentrated force and power. A fast control valve brings pressure onto a drive piston which then accelerates the valve mass against the force of the valve spring.
At the point of force balance the valve has its top speed and keeps moving until its kinetic energy is exhausted. A simple check valve in the fluid flow path prevents back flow and thus keeps the valve in its highest opening position. This valve lift hight is controllable via the pressure level.
For more information and to see how hydraulic energy is recuperated watch the video or read
Flexwork was tested on a 1.4 l spark ignited engine. Flexwork allows full load control by nearly loss-
free valve timing instead of the energy demanding gas throttling.
Results from the engine test bench were taken to simulate the fuel consumption of a passenger car
in different drive cycles.
Best values are reached with cylinder cut-off which is easily done with this variable valve train.
Also hybrid constellations (internal combustion engine + electro engine) would profit.
Flexwork Variable Valve Train advantages in different drive cycles for a typical medium sized passenger car (1500 kg, 2l-gasoline-engine) measured in CO2.
NEDC New European Driving Cycle
WLTC World harmonized Light Vehicle Test Procedure