Dynamic Response Analysis of the Main Plunger in A Two-stage On/Off Poppet Valve for the Digital Hydraulics Field

The necessity for greater energy conservation in hydraulic machinery is highlighted by escalating fuel costs and heightened ecological awareness. Utilizing independent metering to enhance the energy utilization of hydraulic actuators is one effective strategy, yet the market is short on efficient reversible proportional valves that can perform this function. For handling modest flow rates up to 150 Liters per minute, the digital hydraulic method utilizing fast direct operated on/off solenoid valves shows promise; however, solutions for managing larger flows remain vague. This research explores the application of pilot-operated solenoid valves in digital hydraulic systems designed for substantial flow volumes. It establishes a model grounded in physical principles to examine how various factors influence the valve reaction speed. A unique valve design was established, derived from an existing valve but with a modified structure.

The findings indicate that the pressure difference, viscosity of the fluid and pilot plunger dynamics are crucial determinants of the valve response time. Incorporating a stroke limiter proves significant in harmonizing the response times across valves with varying flow rates, while the traditional methods of deploying serial orifices is deemed unsuitable. A glance from the results shows that at a Δ
P of 10 bar, the valve with an 8 mm attached serial orifice has an opening response of 65 ms, while the stroke limited valve achieves 40 ms. This significant advantage slightly narrows at higher pressures, stabilizing at 100 bar. During closing, the stroke limiter is remarkably 60% faster at 10bar, and both configurations settle at 40 ms at 200 bar.