Why Mazda Discontinued the RX-7’s Rotary Engine and What the Future Holds

Mazda's powerful and distinctive rotary engines, seen in cars like the RX-7, have captured the imagination of automotive enthusiasts for decades. However, the reasons behind their discontinuation are rooted in modern automotive demands for efficiency and emissions compliance.

Technical Challenges and Past Decline

The decline of Mazda’s rotary engine in the late 20th century was largely due to its inefficiency and maintenance needs. Specifically, these engines had issues with poor fuel economy, frequent need for seal replacements, and excessive oil consumption. These factors made it a poor fit in a market that increasingly demanded strict fuel efficiency and stringent emissions standards.

Current Status and Future Potential

Despite these challenges, Mazda still manufactures rotary engines, albeit for a different purpose. Rather than powering their vehicles, these engines are being considered as range extenders for hybrid vehicles. The Wankel design of these engines allows them to provide significantly more horsepower relative to their size. This makes them ideal for extending the lifespan of electric vehicle batteries during long trips.

How does it work? When the main battery of an electric vehicle runs low, the small rotary engine kicks in to charge the battery and provide enough power to run the main electric motors, ensuring the vehicle stays operational.

Historical Context: Rotary Engines in Aviation

The rotary engine, with its unique design, has a long and varied history in aviation as well. Unlike the radial engines that may look similar, early WW1 fighter planes used rotary piston/cylinder technology where the crankshaft was attached to the aircraft, and the propeller was linked to the crankcase. This design exploited centrifugal force to act as both a fuel and an oil pump, offering some advantages in terms of simplicity and efficiency.

However, this design also posed significant maintenance issues, leading to frequent and expensive repairs.

Future Possibilities

While the original purpose of the rotary engine in automotive use was hindered by modern fuel economy and emissions standards, its potential in hybrid electric vehicles remains promising. Mazda is exploring ways to leverage this design, recognizing its advantages in terms of power density and efficiency.

Note: For a deeper dive into the technical specifics of the Wankel engine, you can check out the link provided below, which offers an excellent write-up on Mazda's Wankel engine.

Conclusion

While the reasons for the discontinuation of the rotary engine in automotive applications are clear, the adaptability and unique benefits of this design ensure its continued exploration and potential in the future of automotive technology.