Okay, this is going to be a long one....I've been working on a project for a couple years now, and am getting somewhere slowly. Here is a bit of background:
The most common type of the internal combustion (IC) engine is the reciprocating piston engine, where a piston moves in a linear motion inside a cylinder observing two/four stroke combustion cycles. The linear motion of the piston is converted to rotary motion of a shaft via a slider-crank mechanism. The reciprocating motion of the IC engine is a historical artefact of its predecessor - the steam engine. Since commercialisation of the IC engine in the mid-1800s, this type of engine has been a driving force behind our exponential technological progress and globalisation.
Despite its massive success, there are a number of drawbacks in the reciprocating piston architecture that cannot be avoided. Some examples include:
* in translating reciprocating motion to rotary motion at the point of peak force (at piston top dead centre) the lever arm in the slider-crank mechanism is zero hence no torque is generated,
* a single cylinder engine is unbalanced generating vibration and wear on the cylinder and piston head,
* there is only one power stroke for every two revolutions of the shaft.
The rotary vane engine has long been proposed as an alternative design to the reciprocating piston engine with the aim of avoiding the above mentioned drawbacks. This type of engine consists of a cylindrical chamber with two shafts either side, each shaft has vanes attached. The vanes create between themselves chambers of variable volume, within which the strokes of the internal combustion cycle can occur. In the case that the chamber is hermetically sealed, and combustion made to occur in one of the chambers, the vanes would oscillate at a natural frequency - hence why the term oscillating piston engine, or vibratory engine is sometimes applied to this design.
The rotary vane engine overcomes the previously mentioned drawbacks of the reciprocating piston engine. A rotary vane single cylinder engine has a constant lever arm, hence non-zero torque output across the full duration of the combustion stroke, low vibration with no linear moving parts, and at least four power strokes per shaft revolution. However, the rotary vane engine is not without its own drawbacks - the most prominent one being that despite many attempts to build a rotary vane engine, none of the proposed designs have been successful in practical tests. The main cause of failure in all known constructions is that they employ mechanical linkages to coordinate shaft rotation. Components in these linkages experience alternating shock loadings, which quickly lead to their destruction.
Our solution to this critical drawback in the rotary vane engine design is to use electrical machines attached to either one or both shafts to achieve necessary coordination between the shafts. Controlling the accelerating and decelerating electromagnetic torques of the electrical machines ensures the necessary coordination of rotation of the shafts, and at the same time conversion of heat energy of the fuel into electrical energy.
