## Which Cars Have Rotary Engines?
### Introduction
Rotary engines, also known as Wankel engines, are a type of internal combustion engine that uses a triangular rotor instead of the traditional pistons and cylinders found in reciprocating engines. This unique design offers several advantages, including a higher power-to-weight ratio, smoother operation, and lower emissions.
### Mazda RX-Series
Mazda is the only automaker that has mass-produced cars with rotary engines. The company’s RX-Series sports cars have been powered by rotary engines since the introduction of the Mazda Cosmo Sport in 1967.
**Notable Models:**
* Mazda RX-7 (1978-2002)
* Mazda RX-8 (2003-2012)
* Mazda RX-Vision concept (2015)
### NSU Ro 80
The NSU Ro 80 was a German sedan that was produced from 1967 to 1977. It was the first production car to be powered by a rotary engine. However, reliability issues plagued the Ro 80, and it was discontinued after only 37,406 units were produced.
### Citroën GS Birotor
The Citroën GS Birotor was a French sedan that was produced from 1973 to 1975. It was the second production car to be powered by a rotary engine. Like the NSU Ro 80, the GS Birotor suffered from reliability issues and was discontinued after only 847 units were produced.
### Advantages of Rotary Engines
* **Higher power-to-weight ratio:** Rotary engines are more compact and lighter than reciprocating engines, which gives them a higher power-to-weight ratio. This makes them ideal for sports cars and other performance-oriented vehicles.
* **Smoother operation:** Rotary engines run more smoothly than reciprocating engines because there are no reciprocating parts. This results in a more comfortable and refined driving experience.
* **Lower emissions:** Rotary engines produce fewer emissions than reciprocating engines because they do not have to overcome the inertia of reciprocating parts. This makes them more environmentally friendly.
### Disadvantages of Rotary Engines
* **Lower fuel efficiency:** Rotary engines are less fuel-efficient than reciprocating engines because they have a lower compression ratio. This means they require more fuel to produce the same amount of power.
* **Higher maintenance costs:** Rotary engines have more complex designs than reciprocating engines, which makes them more expensive to maintain.
* **Reliability issues:** Early rotary engines were plagued by reliability issues, but Mazda has since addressed many of these problems. However, rotary engines still require more frequent maintenance than reciprocating engines.
### Conclusion
Rotary engines offer several advantages over reciprocating engines, including a higher power-to-weight ratio, smoother operation, and lower emissions. However, they also have some disadvantages, such as lower fuel efficiency, higher maintenance costs, and reliability issues. Mazda is the only automaker that currently produces cars with rotary engines, and the future of this technology remains uncertain.
