wankel engine

Say, whatever happened to the Wankel engine? It was supposed to be the greatest thing since the ballpoint pen. We heard that it was going to revolutionize the industry. Why hasn’t it?

The efficiency and emissions of real-world Wankels, as opposed to mathematical models, turned out to be no better than the common Otto-cycle engine. Also, erosion of the tip seals never really got solved.

Very unreliable. I think its a cool idea, just to have something different, but who’s willing to risk the money, and their reputation on it?

Well, Mazda worked out the tip seal problem fairly well and got the reliability into “pretty good” territory, but the darned things are still a little thirsty. Not that important in sports cars, like the old RX-7, but undesireable in regular cars.

The engine I’ve been wondering about is the Stirling. (Not to be confused with badge-engineered Hondas named Sterling.)

You can get them again.

Mazda is releasing an updated rotary, called the RENESIS in the RX-8. They’ve been showing the RX-Evolve concept car for a couple of years now:


The problem with the Stirling is that you can’t just turn it on and go. With the standard engine you get in your car, turn on the ignition and back out of the driveway. With a Stirling you get in the car, turn on the ignition then wait while the engine comes up to operating temperature (which can be several minutes).

I understand Ford was working on one back in the '70s that could start moving (slowly) after about 30 seconds, then the oil crisis ended and most everyone lost interest in fuel effenciency.

I had an RX-7 and found it to be quite reliable. It didn’t hum like the commercial said but it was a lot quieter than a normal engine. It never had a mechanical problem… had lots of power and torque… but poor gas milege. It was great when gas was $1.05 a gallon… but not so good when it went up to $2.00 a gallon.

With a name like Wankel it should be popular. It’s just so fun to say: “I’ve got a Mazda. It’s got a Wankel.”
“A what?”
“A Wankel”
“Stop talkin’ dirty!”
“What? I’ve got a Wankel!”
“Well whudidja do that for?”