FLUID-WORKING MACHINE AND METHOD OF OPERATING A FLUID-WORKING MACHINE

摘要

Disclosed is a method of detecting a fault in a fluid-working machine comprising a plurality of working chambers of cyclically varying volume, each said working chamber operable to displace a volume of working fluid which is selectable for each cycle of working chamber volume to carry out a working function responsive to a received demand signal. An output parameter of the fluid working machine, which is responsive to the displacement of working fluid by one or more of the working chambers to carry out the working function, is measured. It is determined whether the measured output parameter fulfils at least one acceptable function criterion, taking into account the previously selected net displacement of working fluid by a working chamber during a cycle of working chamber volume to carry out the working function. By taking into account the previously selected net displacement of working fluid by a working chamber during a cycle of working chamber volume to carry out the working function, an unacceptable fault in a fluid-working machine may be detected if it causes one or more measured output parameter to respond in a way which would not be expected if the fluid working machine was functioning acceptably.