The Wankel Rotary Engine: pros and cons of its unique design
The Wankel Rotary Engine: pros and cons of its unique design
Before we dive into the pros and cons of the legendary Wankel Rotary Engine, it’s important to understand why it’s so unique in the first place.
A brief explanation:
In a conventional engine, pistons slide up and down through cylinders, the pistons go through cycles of air intake, compression, combustion and exhaustion. Each cylinder is one combustion chamber. The most common modern engine configurations are either a turbocharged inline 4 or a naturally aspirated v6.
In a Rotary Engine, rotors revolve about an eccentric shaft in a chamber. These also go through compression cycles, but many processes can occur at the same time because of the rotor’s three faces. Each rotor has 3 combustion chambers. The most popular configuration is a turbocharged 2 rotor, however, custom 3 or 4 rotor engines have been made.
(I’d recommend checking out some gifs to get a better idea of how both engines function)
Pros of the rotary:
They sound amazing
Due to the high rpm of Rotary Engines, and the fact that the rotor is essentially a very quickly rotating flywheel, it produces a simply extraordinary sound. The only sound that comes close to it is that of a 10 cylinder conventional piston engine.
They produce lots of power
The rotary has 3 combustion cycles per revolution of the engine as opposed to 1 per 4 revolutions. This means the rotary creates lots of power. Dramatic power increases can be seen with the addition of a turbocharger, which is why they often came with them from the factory.
The engines are compact and light
Rotary Engines are far more compact than their piston counterparts for a variety of reasons, mostly, their lack of extra parts. This is due to the unique engineering that went into the Wankel Engine.
Cons of the rotary:
They guzzle gas
Back when rotaries were conceived, fuel economy wasn't a concern, and because rotaries are fairly unevolved, they were never designed with the intent of being fuel efficient.
They guzzle oil
Rotaries are famous for burning excess amounts of oil. Rather than changing your oil on a monthly basis, it’s recommended that rotary owners top up their oil after every other time they fill up gas. This is because there is no better way to keep the engine lubricated than by injecting it directly into the combustion chamber.
They don't produce a lot of torque
Incidentally, the rotary’s high rpm levels don’t allow it to produce a lot of torque. This means they need lots of gears to get them up to speed, which adds weight and slows the car down.
All in all, the power, sound, uniqueness, and legend surrounding owning a car with a Wankel Rotary Engine should be enough to make any automotive enthusiast fall in love with this incredible feat of engineering.
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