Patent ID: 9091253
Filing Date: 2015-07-28
Classification: F01B,F04B,Y10T

Abstract:
1. A fluid working machine comprising: a controller and a working chamber of cyclically varying volume, the working chamber having an electronically controllable primary low pressure valve associated therewith to control the connection of the working chamber to a first low pressure manifold by a first path, the controller being operable to actively control at least the primary low pressure valve, in phased relationship to cycles of working chamber volume, to determine the net displacement of fluid by the working chamber on a cycle by cycle basis, wherein the working chamber further comprises a secondary low pressure port which is openable and closable in phased relationship to cycles of working chamber volume to connect the working chamber by a second path to either the first low pressure manifold or a second low pressure manifold different from the first low pressure manifold, to enable fluid to flow into or out of the working chamber concurrently and in parallel through both the primary low pressure valve and the secondary low pressure port during a portion of at least some cycles of working chamber volume, wherein the primary low pressure valve and the secondary low pressure port are openable concurrently and in parallel at the point in an expansion or contraction stroke where the rate of change of volume of the working chamber is greatest.