The
air pump for the beach raft is a good example for the use of the passive
valves. In the air pump, simple flaps work as the valves, and
the pressure change in the pump makes them open and close.
The
air pump for the beach raft is a good example for the use of the passive
valves. In the air pump, simple flaps work as the valves, and
the pressure change in the pump makes them open and close.
On the other hand in 4 cycle engine, the
intake and exhaust valves (red arrows) are opened and closed actively
by a timing belt or the cam-gear train (not shown). Precise flow control
can be made in this system.