A hydraulic system employing an electronically commutated fluid working machine having working chambers, each having one or more electronically controllable valves actively controlled by a controller to regulate the net displacement of working fluid into or out of low- and high-pressure manifolds on a cycle by cycle basis to meet an indicated demand. The high-pressure manifold has an additional outlet, regulated by a controllable outlet valve. If the demand indicated by a demand signal is expected to cause pulsatile flow or vibrations which may excite resonant modes, the controller causes the displacement of working fluid by the working chambers to exceed the demand indicated by the demand signal, and the controller simultaneously opens an electronically controllable outlet valve to allow some of the excess flow to leave, such that the net displacement of fluid meets the demanded displacement of fluid, while mitigating the pulsatile flow or undesirable vibrations.

Highly efficient pressure differential rotary engines can include rotatable cylinders arranged radially around a central stationary shaft. Each of the cylinders can house one or more pistons, and the cylinders and pistons can rotate together about the central stationary shaft. Pressure differentials within the cylinders can be used to power the rotation of the cylinders about the central stationary shaft.

A rotary heat engine including a central crankshaft and a plurality of cylinder assemblies and a heat exchanger assembly. At least one of the plurality of cylinders, and preferably all of the plurality of cylinders includes a cylinder member, a piston member slidably positionable within the cylinder member, a connecting rod and a rolling diaphragm. The rolling diaphragm is positioned between the piston and the cylinder assembly to define a working volume which is in fluid communication with an opening that is in communication with the heat exchanger body.

A rotary heat engine including a central crankshaft and a plurality of cylinder assemblies and a heat exchanger assembly. At least one of the plurality of cylinders, and preferably all of the plurality of cylinders includes a cylinder member, a piston member slidably positionable within the cylinder member, a connecting rod and a rolling diaphragm. The rolling diaphragm is positioned between the piston and the cylinder assembly to define a working volume which is in fluid communication with an opening that is in communication with the heat exchanger body.

Highly efficient pressure differential rotary engines can include rotatable cylinders arranged radially around a central stationary shaft. Each of the cylinders can house one or more pistons, and the cylinders and pistons can rotate together about the central stationary shaft. Pressure differentials within the cylinders can be used to power the rotation of the cylinders about the central stationary shaft.

A rotary heat engine including a central crankshaft and a plurality of cylinder assemblies and a heat exchanger assembly. At least one of the plurality of cylinders, and preferably all of the plurality of cylinders includes a cylinder member, a piston member slidably positionable within the cylinder member, a connecting rod and a rolling diaphragm. The rolling diaphragm is positioned between the piston and the cylinder assembly to define a working volume which is in fluid communication with an opening that is in communication with the heat exchanger body.

A rotary heat engine is comprised of a central crankshaft, a plurality of cylinder assemblies, and a plurality of heat exchanger assemblies. The central crankshaft has first end and a second end defining an axis of rotation. The plurality of cylinder assemblies are coupled to the central crankshaft. The plurality of heat exchanger assemblies are each associated with the plurality of cylinder assemblies, respectively.