What are the prospects facing new ideas in fluid power?

The field Of fluid power components and systems is characterized by a process of steady evolution, intended to improve functionality and reduce constructional effort. In many cases, these improvements were due to advances in related technologies, such as electrics, electronics, computer science, control technology, or material sciences. However, during the many decades for which fluid power has been used, wholly new ideas have appeared every now and then, allowing particular tasks to be accomplished in a better way. Any innovation must not only improve specific functions, it must also do so at a similar or better price than extant technology, or it must offer additional functionality in order to justify a higher cost. Moreover, it must match engineering's state of the art in terms of other criteria such as lifespan, constructional effort, operational safety, and energy efficiency. Examples of past innovations that failed to clear this hurdle and hence did not gain widespread acceptance in spite of intensive research and development are Fluidics and Alternating Flow Hydraulics (AFH). Remnants of Fluidics-technology are to be found not in hydraulics or pneumatics but in wastewater handling. Drawing upon a range of more recent examples, this paper shall chart the reception that some new ideas and developments have received. Their technical and economical advantages and disadvantages decide whether they succeed within a particular area of application or fall into oblivion. Examples treated comprise the secondary control of hydromotors, the free piston engine, new means of valve actuation, noise reduction by pre-compression volume, bus technology, and the fuel cell. The conclusion to be drawn from this investigation is that, owing to their clear benefits, some innovations quickly find wide acceptance and are widely applied. Other innovations have inherent weaknesses as well as some advantages, which renders it harder for them to penetrate the market. Sometimes, a hitherto-neglected principle of operation may attract renewed interest due to developments in neighbouring disciplines.