The Wankel engine, also known as the rotary engine, is a unique type of internal combustion engine that differs significantly from the traditional piston engine. Known for its compact design, smooth operation, and high-revving nature, the Wankel engine has been used in several vehicles throughout automotive history, though it remains relatively rare compared to conventional engines. Car enthusiasts and engineers often admire Wankel engines for their engineering innovation, but only a select group of manufacturers have incorporated them into production cars. Understanding which cars use Wankel engines helps highlight their unique characteristics and the reasons behind their limited adoption.
Understanding the Wankel Engine
Developed by German engineer Felix Wankel in the 1950s, the Wankel engine replaces the reciprocating pistons of a traditional engine with a triangular rotor that rotates inside an epitrochoidal chamber. This design allows for fewer moving parts, a compact and lightweight structure, and a smooth power delivery. The engine is particularly known for its high power-to-weight ratio and ability to achieve high engine speeds, making it popular in sports and racing cars. However, Wankel engines also face challenges such as higher fuel consumption, emissions issues, and apex seal wear, which have limited their widespread use.
Key Advantages of Wankel Engines
- Compact and lightweight design, making it ideal for sports cars.
- Smoother operation with less vibration due to continuous rotary motion.
- High-revving capabilities, producing impressive power in a small displacement.
- Fewer moving parts compared to piston engines, reducing mechanical complexity.
Cars That Use Wankel Engines
Though the Wankel engine is innovative, very few manufacturers have produced vehicles with this technology. Mazda is the most prominent company to consistently utilize Wankel engines in their production cars, while other manufacturers have experimented with rotary engines for limited applications or concept vehicles.
Mazda RX Series
Mazda has been synonymous with Wankel engines for decades, most famously through its RX series. The RX-7 and RX-8 are iconic sports cars that showcase the rotary engine’s performance potential.
- Mazda RX-7 (1978 2002)One of the most popular rotary-engine sports cars, the RX-7 was produced across three generations. Known for its lightweight chassis, balanced handling, and turbocharged rotary options, it gained a loyal following among car enthusiasts.
- Mazda RX-8 (2003 2012)The RX-8 continued Mazda’s rotary tradition with a modern design, four doors, and the Renesis engine, which addressed some of the emission and reliability concerns of earlier models.
Mazda Cosmo
The Mazda Cosmo is another historically significant Wankel-powered vehicle. Introduced in the 1960s, the Cosmo Sport (also known as the 110S) was the first production car to feature a twin-rotor rotary engine. It laid the foundation for Mazda’s commitment to rotary technology and remains a collector’s favorite today.
Concept and Limited-Run Vehicles
Beyond production sports cars, Mazda and other manufacturers have experimented with Wankel engines in concept vehicles and limited runs
- Mazda RX-Vision ConceptUnveiled in 2015, the RX-Vision concept showcases Mazda’s vision for a modern rotary-powered sports car, highlighting its lightweight design and high-performance capabilities.
- Mazda Cosmo 20B (limited edition)Some special editions featured three-rotor engines, delivering higher output and demonstrating the versatility of the rotary design.
- NSU Ro 80Produced by German automaker NSU in the late 1960s and early 1970s, the Ro 80 featured a Wankel engine and was noted for its futuristic styling and smooth rotary operation, although reliability issues limited its commercial success.
Why Wankel Engines Are Rare
Despite their unique advantages, Wankel engines are uncommon in modern vehicles. Several factors contribute to this rarity
Fuel Efficiency and Emissions
Rotary engines are generally less fuel-efficient than piston engines and produce higher emissions. Stricter modern environmental regulations have made it difficult for manufacturers to justify Wankel engines in mass-produced cars without significant technological advancements.
Maintenance and Durability
The apex seals in a Wankel engine, which maintain the seal between the rotor and the chamber walls, are prone to wear. This can lead to compression loss and increased maintenance requirements, making the engine less appealing for everyday vehicles compared to conventional piston engines.
Limited Commercial Adoption
Only a few manufacturers, notably Mazda, have successfully implemented Wankel engines at scale. Other automakers often experimented with rotary engines in concept cars or racing vehicles but faced challenges in scaling production due to cost, reliability, and emissions concerns.
Current and Future Applications
While the Wankel engine is rare in production cars today, it has potential applications in hybrid vehicles, range extenders, and lightweight sports cars. Mazda has expressed interest in reintroducing rotary engines as a range-extender for electric vehicles, where the engine operates at a constant speed to generate electricity rather than directly powering the wheels. This application could leverage the rotary engine’s compact size and smooth operation while mitigating fuel efficiency and emissions issues.
Racing and Motorsports
Rotary engines have also maintained a presence in racing and motorsports. Their high-revving nature and lightweight design make them well-suited for endurance racing and compact sports cars. Mazda’s success in events like the 24 Hours of Le Mans, particularly with the 787B in 1991, which won the race, highlights the competitive potential of Wankel engines.
Cars that use Wankel engines are relatively rare, with Mazda being the most significant manufacturer to embrace this innovative technology. From the iconic RX-7 and RX-8 to historic models like the Cosmo and racing legends, the rotary engine has left a lasting mark on automotive history. While challenges such as fuel efficiency, emissions, and maintenance have limited widespread adoption, the Wankel engine remains a symbol of engineering creativity and performance potential. Future applications, including range extenders for electric vehicles and racing platforms, may offer new life to this unique powerplant. Enthusiasts continue to appreciate Wankel-powered cars for their smooth operation, high-revving performance, and distinct character, keeping the legacy of the rotary engine alive in both collectors’ garages and concept designs for years to come.