Rotary Engine: why not more?
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Historically rotary engines have been a cheap way to produce good power, but they die quickly and suck a TON of gas (hence why Mazda killed most rotary production during/after the oil shock in the 70's).
We'll see how the Renesis fairs.
We'll see how the Renesis fairs.
To be fair it's really only mazda that is researching rotary engines. We would definately have better engines if all the automotive makers were developing them.
The problem right now as evident on the RX8 forums is that the engine makes a hell of alot more heat than a standard piston engine, and the RX8 eats gas like a V8. But it's alright for now as the RX8 is after all a sports car.
I think the reliability with the rotaries aren't a big deal actually, they seem to happen because of the heat generated by the engine combined with the turbo causing the apex seals to break.
The problem right now as evident on the RX8 forums is that the engine makes a hell of alot more heat than a standard piston engine, and the RX8 eats gas like a V8. But it's alright for now as the RX8 is after all a sports car.
I think the reliability with the rotaries aren't a big deal actually, they seem to happen because of the heat generated by the engine combined with the turbo causing the apex seals to break.
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Mostly because they're trying to differentiate themselves, the same way they did in hte 60's/etc.
the rotary design has to "inject" oil due to the fact they can be no splash oiling from the rotating crankshaft on a piston engine. Imagine how dificult it is to keep the emmision levels below EPA spec in your engine. Then start injecting pure oil directly into the combustion chamber.
Yes Schulkw, now uyou can be happy! 
But, as you know, I have to point this out:
Two threads on the rotary were created. This one and http://mazda3forums.com/viewtopic.php?t=517
But, as you know, I have to point this out:
Two threads on the rotary were created. This one and http://mazda3forums.com/viewtopic.php?t=517
As an RX-7 owner for many years (and recently an MZ3GT owner ), I thought I would chime in and clear up a few myths:
Yes, they do inject oil but in minute amounts - you might use a half quart every few thousand miles - by no means a pollution issue.
Yes, they do run very hot (1800 to 2000 degrees) and that is normal for this car. However, if you run them hotter than this, it can cause o-ring issues (not apex seals) - the rings are rubber and will turn as hard a rock if overheated. Hardened (and leaky o-rings) is not normal and is usually caused by poor maintenance, ie; vac leaks that cause a lean condition and thereby causing the engine to run too hot. Don't overheat a rotory and they will typically out live a boinger.
Gas milage is bad due to the design of the engine - wasted spark is the term sometimes used meaning the engine will actually not burn off all the fuel through the combustion cycle - this is where the pollution issue comes from and why the early rotaries had 3 catalatic converters. The RX-8 solves the issue to some extent by redesigning the porting. the RX-7's were brutal on gas - in the low teens for gas milage unless they were well tuned.
The biggest advantage to a rotory is the small displacement to HP ratio - smaller, light weight 1.1 and 1.3 litre engines that provided upwards of 200+ HP had a huge advantage over the piston - also the light weight, very nimble, and almost perfect 50/50 weight distribution. Plus the extremely flat torgue curv - meaning the car built power right up through the rev range rather than producing most of it's peaky power in the higher range as do most of the multi value piston engines (can you say HONDA?)
), I thought I would chime in and clear up a few myths:Yes, they do inject oil but in minute amounts - you might use a half quart every few thousand miles - by no means a pollution issue.
Yes, they do run very hot (1800 to 2000 degrees) and that is normal for this car. However, if you run them hotter than this, it can cause o-ring issues (not apex seals) - the rings are rubber and will turn as hard a rock if overheated. Hardened (and leaky o-rings) is not normal and is usually caused by poor maintenance, ie; vac leaks that cause a lean condition and thereby causing the engine to run too hot. Don't overheat a rotory and they will typically out live a boinger.
Gas milage is bad due to the design of the engine - wasted spark is the term sometimes used meaning the engine will actually not burn off all the fuel through the combustion cycle - this is where the pollution issue comes from and why the early rotaries had 3 catalatic converters. The RX-8 solves the issue to some extent by redesigning the porting. the RX-7's were brutal on gas - in the low teens for gas milage unless they were well tuned.
The biggest advantage to a rotory is the small displacement to HP ratio - smaller, light weight 1.1 and 1.3 litre engines that provided upwards of 200+ HP had a huge advantage over the piston - also the light weight, very nimble, and almost perfect 50/50 weight distribution. Plus the extremely flat torgue curv - meaning the car built power right up through the rev range rather than producing most of it's peaky power in the higher range as do most of the multi value piston engines (can you say HONDA?)
Ford, a long time ago (mid 80s? not sure) made a rotary engine. It was somewhat a replica of the legendary 13B. They couldnt get it to perform so they scraped the whole project as a whole.
Another advantage a rotary has over typical piston engines is: less rotational mass inside the motor. Hence why the RX7/8 can rev up to 10k.
Another advantage a rotary has over typical piston engines is: less rotational mass inside the motor. Hence why the RX7/8 can rev up to 10k.
We may be seeing more rotary engines in the future...
http://www.edmunds.com/news/autoshows/articles/100643/page019.html
It seems they're easier to convert to hydrogen power than conventional piston.
Now we just have to wait 20 years for the hydrogen infrastructure to be built up. :lol:
http://www.edmunds.com/news/autoshows/articles/100643/page019.html
It seems they're easier to convert to hydrogen power than conventional piston.
Now we just have to wait 20 years for the hydrogen infrastructure to be built up. :lol:
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That's what I heard too. Or something along those lines.vaBooM said:
Rotaries have been around for quite a while. But not really worked on that much.
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They are, AK/47, but don't produce nearly as much power when using hydrogen.
Yeah, that's why they started with gasoline in the first place, it had the best yeild for energy/volume.MZ6ZoomZoom said:
But if H2 is the cheap/clean solution it's being hailed as, I could handle a three rotar putting out 200 HP or so. However, there's a long way to go before that happens.
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