Simulink-model based study of flow rate characteristic of directional control valve under different fault conditions

Abstract

Directional control valves perform a vital role in operating any hydraulic system accurately. It is a component working continuously with the fluid flowing at high pressure and controlling the volume and direction of the fluid to be supplied to the actuator. Any component working under such circumstances is prone to failure. The failure in the DC valve can be in the form of leakage due to wear at the surface of any internal part. Also due to moisture inside the valve, corrosion and binding may result in improper movement of spool and can lead to spool stuck situation. This project studies the flow rate behaviour of a four-port three-way directional control valve under ideal conditions and multiple leakage faults situations. The flow rate characteristic curve under healthy parameters is used to form a comparison study with flow rate characteristic curves obtained under leakage fault conditions. In the later part of the study, fault in spool movement is also incorporated, causing the improper opening of the orifice, and affecting the desired flow rate. From the comparison study of leakage, it has been concluded that the variation of flow rate is less with 10% fault in directional control valves as compared to the extreme case of 90% fault. And with fault in spool movement, we have observed that flow rate value increases with wear in orifice and then starts to decline with increase in fault in the spool.