Rotary Engine; it is always confused with ‘Radial Motor’ and ‘Rotary Wankel Motor’ in general. ‘Rotary Wankel Motor’ in terms of name and ‘Radial Motor’ in terms of appearance. So much so that the Rotary Engine; He was a pioneer in the development of the Wankel Engine and the Radial Engine. The Rotary Motor, which was used in many areas during its first release, is not used today. It has been used by many famous aircraft, especially in the aviation industry.
Rotary Motor was first introduced to the stage of history by the French bicycle brand ‘Felix Millet’. Motorcycles using Rotary Motor for the first time in history were made by Felix Millet brand. The 5-cylinder Rotay Engine was developed in 1887 by the French inventor, Felix Theodore Millet. Later, it was mounted on the rear wheel of a bicycle and Rotay Motor was used in this way for the first time in history. Rotary Engine has started to be used in the aviation industry later on. Rotary Engines were used on all aircraft in the First and Second World Wars. Later on, Radial Motors started to replace Rotary Motors.
In 1998, Rotary Motors were started to be used by the automotive brand Adams Farwell. However, it failed due to its inability to perform proper cooling, and it was withdrawn from the automotive industry in its tenth year.
What is a Rotary Motor?
Rotary Engine is a type of internal combustion engine. Although it functions the same as the engines used today, it has the same timings. For example; “Intake, Compression, Ignition and Exhaust.” timings are the same. There are certain aspects of Rotary Motors that differ. One of them is that it has a mass rotating around its axis. In addition, water cooling system is not used in Rotary Motors. Instead, an air-cooled system is used. Rotary Motor has a rotating mass. The crankshaft in these engines is fixed. The crankcase rotates around the crankshaft.
How Does a Rotary Engine Work?
The working principle of Rotary Motors is the same as the working principle of today’s motors. The only difference is the rotating mass of Rotary Motors. In Rotary Engines, the crankshaft is stationary. In a normal internal combustion engine, the crankshaft is in motion. With the movement taken from the piston, the crankshaft also moves. It transmits this movement to the gearbox. However, the situation is different with Rotary Motors. The crankshaft of the rotary engine remains stationary. Combustion chambers lined up around the crankshaft begin to rotate around the shaft. There are pistons inside the combustion chamber. These pistons go back and forth between the Bottom Dead Center (A.O.N) and the Top Dead Center (U.O.N). This ensures that the times (Intake, compression, work, exhaust) are formed.
The rotation of the Rotary Engine’s mass around the crankshaft does not contribute to the way it works. It does not contribute in any way to the movement of the pistons or the speed of the vehicle. The working principle of the Rotary Engine is the same as a normal internal combustion engine. The only difference is that it has a rotating sump.
Rotary Engine Runtimes
Rotary Engine is an internal combustion engine with Otto Cycle. It has the same operating times as the internal combustion engines with the Otto cycle. These times are ‘Intake, Compression, Work (Ignition) and Exhaust’. Let’s look at how these runtimes are formed in turn.
Suction Time: The first time that occurs in the rotary engine is the suction time. When this time starts, the intake valve opens fully. This ensures that the air-fuel mixture is filled into the cylinder. Meanwhile, the piston moves towards A.Ö.N. The mixture filled in allows the piston to descend from the upper part to the lower part. When the piston reaches the bottom, the intake valve closes and the intake time ends.
Compression Time: The piston advancing from the lower part to the upper part will ensure that the mixture inside is compressed. Meanwhile, both the intake and exhaust valves are closed. This ensures that my inside mix is not leaked. In addition, it is ensured that the mixture inside is easily compressed.
Work (Ignition) Time: The piston reaching the upper part has thoroughly compressed the mixture inside. At work time, the compressed mixture in the cylinder starts to burn. The piston comes to the upper part by compressing the mixture. Afterwards, the ‘Spark Plug’ sparks, allowing the compressed mixture to burn. With this combustion effect, a high pressure occurs in the cylinder. The pressure causes the piston to move towards the bottom.
Exhaust Time: The exhaust time is the last action that takes place in the cylinder. After the work time is over, the piston reaches the lower part. There are residual burnt gases in the cylinder. The exhaust valve opens, the piston starts to move upwards. As the piston goes up, it also pushes the burned gases inside the cylinder. With this pressure, the burned gases are thrown out through the exhaust valve. When the piston reaches the highest point, the exhaust time ends and this cycle continues by starting the intake time.
Rotary Motor Advantages
Rotary Motor also comes to the fore with its beautiful advantages. Thanks to these advantages, the engine reached many people in a short time, and it was appreciated by these people. Although it is not very popular in the automotive industry, it has been used in the aviation industry for many years.
The advantages of the engine in general are as follows;
* It has a light structure due to the small number of parts.
*It is a highly efficient engine compared to the internal combustion engines used today.
*Since it is air cooled, there is no need for additional water cooling system.
* Thanks to the rotating mass of the engine, it is easily cooled by air. The propellers used in normal air-cooled engines are not needed.
Rotary Engine Disadvantages
Rotary Motor, which has disadvantages as well as advantages, has not been widely used in the automotive industry due to these disadvantages.
The disadvantages are as follows;
*Fuel consumption is high.
*Since the lubrication process is not complete, wear and expansion of the parts is inevitable. This will cause malfunction in a short time.
*The control of Rotary Engines, especially used in airplanes, is very difficult. Pilots need access to high experience in this field. Inexperienced pilots find it difficult to control these powered airplanes.
*It works noisily.
Why Rotary Motors Rotate
Rotary engines are fixed to a fixed crankshaft. The crankcase rotates clockwise around the stationary crankshaft. This is different for radial engines. In radial engines, the crankshaft rotates, the crankcase remains stationary. However, in these engines, the crankcase rotates around the crankshaft.
There are two reasons why the engine rotates around the crankshaft. The first reason is to allow the engine to cool easily. The air that fills the gaps in the crankcase of the engine allows the engine to cool. It renews this air by constantly rotating, allowing it to cool easily. The second reason is to maintain balance. As the engine rotates, the weight equalizes. This prevents the vehicles from losing balance.
Writer: Sinan Karadas