Wankel Rotary Engines in Consumer Vehicles: A Legacy and a Possible Revival

While Wankel rotary engines have not been widely used in consumer vehicles in the past few decades, their distinctive sound and performance characteristics continue to attract enthusiasts and automotive engineers alike. Despite their challenges, including fuel efficiency and maintenance issues, there is renewed interest in rotary engines, as seen in recent concept cars from Mazda. This article explores the use of rotary engines in consumer vehicles, focusing on their history, pros and cons, and the potential for a revival.

Historical Context and Distinctive Features

The Wankel rotary engine, developed by German engineer Felix Wankel in the early 1950s, seemed destined for a promising future in the automotive industry. Designed around a triangular rotor that orbits within an egg-shaped combustion chamber, the rotary engine offered several advantages over traditional reciprocating engines, including a simplified design, higher efficiency, and smoother operation. However, the technology faced significant challenges, particularly with fuel consumption and emissions, which made it less appealing in the 1970s and 1980s.

Fuel Economy and Maintenance Concerns

One of the primary drawbacks of rotary engines is their poor fuel economy. Users often encountered significant fuel consumption issues, even under conservative driving conditions. For example, according to the author's acquaintance who owned an RX-8, the car struggled to achieve even 12L/100km (or approximately 20mpg) despite careful driving practices. The RX-7, another notable rotary-powered vehicle, required frequent oil changes, with owners often changing the oil every 2000 miles to prevent carbon buildup, which necessitated intensive high-rev runs to mitigate.

Modern Comparisons and Market Dynamics

When compared to modern engines, particularly those with higher performance capabilities, the rotary engine seems less competitive. Today, a 4.0L V8 can consistently achieve fuel efficiencies well below 10L/100km (around 25mpg) while requiring fewer maintenance checks. This higher efficiency and lower maintenance make modern V8 engines more attractive to most consumers, although they might be less appealing to those who desire the unique driving qualities of a rotary engine.

Potential for Revival: Mazda's Interest

Despite the challenges, there are signs of renewed interest in rotary engines. Mazda, the only major automaker to have commercially produced a rotary engine, has been teasing the possibility of a rotary revival in recent years. Concepts such as the Mazda RX-Vision and Vision Gran Turismo showcase elements of rotary technology, suggesting that the company may be exploring potential applications in the future. These concepts highlight the continued fascination with the rotary engine and its potential to offer distinctive performance and driving characteristics.

Conclusion

The Wankel rotary engine, while not widely used in consumer vehicles today, remains a legend in the automotive industry. Its unique features and distinctive sound continue to intrigue automotive enthusiasts and engineers. Although the current comparison suggests that modern engines offer better fuel efficiency and lower maintenance, there is a possibility for a rotary engine revival, as evidenced by Mazda's ongoing interest. As technology advances, the potential for a return of the rotary engine cannot be entirely ruled out, making it an engine to keep an eye on for future developments.