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End of an Era: Mazda Building Last Rotary Engine

Gone (for now)...but not forgotten.

by on Jun.28, 2012

Mazda briefly stretched out the rotary engine's final run with production of the special-edition RX-8 Spirit.

It has been a mainstay of the brand’s powertrain line-up for more than four decades but in the coming days Mazda will produce the last of its one-popular rotary engines as it halts production of the RX-8 sports car.

The rotary, also known as a Wankel, for its inventor, helped make the Hiroshima-based automaker – but also nearly destroyed it, as well, when a series of major design flaws were discovered leading to endemic early engine failures. But while improvements in the design allowed Mazda to maintain the rotary for quite some time the engine just couldn’t keep up with today’s fast-rising fuel economy standards.

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“Production of the RX-8 will end, but the rotary engine will live on as an important part of Mazda’s spirit,” said Mazda President Takashi Yamanouchi, in a prepared statement.

The rotary engine was developed by German engineer Felix Wankel just after World War II, but it took until the 1960s before automakers began taking a serious look at the technology.

Mazda's focus now is on high-mileage models, like the new CX-5, equipped with the SkyActiv system.

Unlike a conventional piston engine, a rotary uses a triangular rotor revolving within an oval chamber to generate power.  It allows for much higher RPMs and generates significantly more power than a piston engine for a given displacement.  Rotaries also are significantly smaller, lighter and use less moving parts.

That led to a number of manufacturers taking out licenses to use rotaries, including Audi progenitor NSU, General Motors and American Motors.  The latter originally planned to use a rotary in its ungainly Pacer model. But only Mazda made a serious go of it, initially turning to the Wankel engine as it made its splashy entry into the U.S. with models like the RX-2 and RX-3.

“Piston engines go ‘boing-boing,’” proclaimed a catchy ad aired in the mid-1970sm Mazda goes hummm.”

Unfortunately, early rotaries quickly went silent.  The mechanical seals between the tips of the rotor and the well of the surrounding chamber failed in catastrophic number, it turns out, forcing Mazda to make extensive repairs and nearly driving the maker into bankruptcy.

(Ironically, the problem was first caught by a then unknown analyst trying to create a firm focusing on quality issues. The headlines that emerged from his reports about the Mazda seal problem turned J. David Power into something of a hero and helped launch the entity now known as J.D. Power and Associates.)

Mazda eventually solved the rotor problem and put the rotary back into its line-up, but by then it faced a different and equally serious challenge: fuel economy.  While the basic design of a Wankel churns out plenty of power for its compact size, the engine has some fundamental inefficiencies that require it to burn far more fuel.  The small engine, it turned out, required a big gas tank.

The higher fuel prices rose – and the more federal regulators ramped up mileage mandates – the more the rotary drifted towards the sidelines.

At its peak, in 1973, Mazda produced 239,871 rotaries.  That also happened to be the year of the first Mideast oil crisis.  In the years that followed, more and more of the maker’s products started going boing-boing as Mazda switched back to piston power.

In recent years, only the unusual 4-door Mazda RX-8 remained in production using the Wankel engine.  And steadily diminishing sales ultimately led the Japanese maker to pull the plug.  It extended the run briefly when nostalgic demand for a final, special-edition RX-8 garnered more sales than expected.

But, for now, Mazda is rotary-less.  However, the maker is yet hinting that a comeback is possible.  During a recent preview of the new Mazda SkyActiv, a new high-technology concept that delivers significantly better mileage than comparable powertrain systems, company officials hinted they have several possible solutions in mind.

But whether they can bring it back into the line-up remains to be seen. Since effectively ending its long-running alliance with Ford Motor Co., Mazda has been struggling financially. Yamanouchi recently said the maker will need to find partners to move ahead and it’s questionable whether another maker would be willing to invest in a revived rotary program.

 

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