If you’re familiar with piston engines, you may have heard the word Wankel associated with rotor engines. But what makes the Wankel rotary engine so unique? Let’s take a closer look.
The Wankel rotary engine was named after its inventor, Felix Wankel. Remarkably, he conceived the idea when he was just 22 years old back in 1929. His vision was to create an engine that was lightweight, efficient, cheap, and easy to repair.
Throughout the 1950s, Wankel worked tirelessly to develop a new type of engine that didn’t rely on cylinders and pistons. Instead, his engine used a triangular rotor and an oval-shaped housing. Some even referred to it as a spinning Dorito, due to its triangular shape.
Why did Wankel choose a triangular shape?
Well, mathematically, it is the most effective configuration within that housing. The rotor revolves around the housing, with all three points of the rotor remaining in constant contact with the edge of the housing. This creates three separate sections that constantly expand and contract as the piston moves around the output shaft.
As the piston moves, a small pocket of air expands into a larger pocket, creating a vacuum. Air and fuel are then injected into this vacuum in the intake parts of the combustion chamber. This mixture is uncompressed against the flat side of the housing and ignited by two spark plugs. Finally, the exhaust gases are forced out at high pressure.
The subject of controversy
Interestingly, the origins of the rotary engine can be traced back as far as the late 1800s. It was initially found in aviation and motorbikes, but the earlier versions were piston engines with a rotating crankcase and an odd number of pistons.
It wasn’t until Felix Wankel came along and created the pistonless rotary engine that we know today. However, this revolutionary engine has been the subject of controversy.
Reasons for Its Decline:
The rotary engine was used in Mazda models like the RX-7, RX-8, and the 787b race car. The engine emits terrible emissions and consumes a lot of oil.
Also, it seems the engine declined in popularity due to emissions regulations, especially in Europe, where Euro 5 emissions regulations were strict. This led Mazda to stop selling the RX-8 in Europe after 2010.
Some inherent problems with the rotary engine, include lower thermal efficiency, carbon buildup, and seal issues. These issues contributed to its decline.
Advantages of the Rotary Engine:
Despite its flaws, the engine has advantages, such as its high power output for its size and lack of vibrations.
Mazda’s efforts to revive it with a range extender for an electric SUV. However, Mazda has filed patents for a new two-rotor Wankel rotary engine design, indicating potential advancements in the technology.
A recent development where a 12-rotor engine was built, which can produce an enormous amount of power but has its own set of challenges, including heat generation and design issues.
Despite its unique design and potential advantages, the Wankel rotary engine has faced criticism and skepticism over the years. Critics argue that it is less fuel-efficient and more prone to issues such as seal wear and oil consumption compared to traditional piston engines.