DESIGN AND VALIDATION OF A SOFT SWITCH FOR A VIRTUALLY VARIABLE DISPLACEMENT PUMP

Switch-mode hydraulic control is a compact and theoretically efficient alternative to throttling valve control or variable displacement pump control. The virtually variable displacement circuit created by a pulse-width modulated high-speed valve has drawbacks, such as large energy losses due to throttling and compressibility during valve transitions. Hydraulic soft switching was proposed as method of reducing the throttling energy loss, by absorbing, in a small variable volume chamber, the flow that would normally be throttled across the transitioning high speed valve. An active locking mechanism was presented by Van de Ven that overcomes the main challenge with soft switching, which is a lock mechanism that releases quickly and with precise timing.