PV Diagram

Anyoon Rotary Engine obeys Otto Cycle perfectly

This IC engine obeys Otto cycle almost perfectly. Only problem in the cycle is with adiabatic compression and adiabatic expansion, by providing effective thermal sealing (Internal cooling by water injection) in the engine we can rectify this problem to some extent. In this engine 4 stages of Atkinson cycle (a more efficient variant of Otto cycle with expansion ratio different from compression ratio) are optimized for better efficiency 2 of them is shown in PV diagram.

1.) Since exhaust side and intake side are separate intake side is cooler than exhaust side and less heat is transferred from rotor to intake charge. So there will be less back pressure and higher volumetric efficiency results. Since charge is cooler higher compression ratio can be achieved.

2.) Since constant volume heat addition is possible by increasing the width of rotor’s one lobe, ignition before compression stroke ends, is not necessary. So there will not be any back pressure due to early combustion. During ignition and constant volume heat addition, volume of charge is considerably low this results in faster flame propagation (since fuel particles in the mixture are closer to each other.) and faster and better combustion results. This, also results in higher temperature with minimum fuel. This will increase efficiency. Also distance from spark plug to most distant fuel particle is lower at the time of ignition, compared to other engine architectures. So surface area is lowest during combustion and less heat is lost to the surroundings.

3.) As you can see in impulse torque graph (high initial torque in each power stroke), most of heat energy is converted into mechanical work earlier than in piston engine. So less heat will be transferred to the surroundings compared to piston engine during power stroke. More than that expansion ratio is increased without changing compression ratio (exhaust volume is higher than intake volume) more heat will be converted to work which is not possible in piston (except with some complicated additional mechanism) or Wankel engine.

4.) In exhaust stroke due to higher expansion ratio pressure of gases will be almost equal to atmospheric pressure. So no valve opening before expansion stroke ends is required. So exhaust blow down loss is reduced. This results in less back pressure during exhaust without losing any power in expansion stroke.

P V Diagram of Anyoon Rotary Engine Including Water Injection