Hydraulics Control System

How does a closed loop hydraulic control system works?

It depends on what you are trying to accomplish. Take some time to explain what you are trying to do and why you are trying to do it.

You will not get an answer unless you are willing to spend the time to give more detail.

Hope to hear back from you.

One example of a closed hydraulic loop is a variable volume constant pressure pump. If the output pressure rises, the increased pressure moves a pump element to make it pump less, therby returning the pressure to the set value. Etc. (There are various methods for this.)

So far as I know, there isn't a pump/motor closed closed loop system that works as you describe. (It sounds as though you are trying to create a perpetual motion machine or over-unity device, neither of which can be done.)

In most modern hydraulic drives there are closed loops build with -at least- a variable pump and a constant motor but most of them have both pump and motor variable in order to make highest energy economy possible. This is NOT a perpetual motion machine since the prime mover of the pump gets its power supply from outside the loop. Such a transmission is a lot more efficient than the use of servo valves since those have a maximal efficiency of 30% and a combination pump + motor can reach 85 to 90 %.

Sorry, old bean, but the quality of your questions hasn't improved in the 4 years since you last posed the question, "what you mean by continuos variable transmission(CVT) in engines?"

If you "save power supply to motor", the pump won't go round-n-round. There will be nothing to control.

See ya.

I think there is another way to look at this subject. It is quite possible to achieve a closed loop control system if there is some form of accumulator in the loop.

A case in point is a water pumping application that we have just installed for a local municipality. A pump pumps water to a header tank that is considerably higher than the highest user in the system. The header tank (accumulator) provides full system pressure to the user until such time as the level reduces to a minimum set point, at which stage the pump restarts and the top level in the tank is restored.

In a similar fashion, a hydraulic accumulator in a system allows the pump and motor to stop while the system is still pressurised awaiting use.

S

I don't understand the question...can you clarify it? Thanks.

Lou Bindner