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Old 11-01-2011, 07:47 AM
  #226  
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Originally Posted by 999miki
+1
Even conventionally injected rotary is capable of quite good BSFC numbers - at full load. At part load its disaster Direct injection as it was examined decades ago is better in whole load range due to absence of throttle plate and overall better combustion thanks to better stratification and burn rate.

The problem with cat converter, in the way Mazda research paper described it, lies in to cold EGTs for proper function of cat. Why is there cat in the first place when such engine can operate with much lower HC and CO emissions than conventional RE is beyond me It must be in something that every car must be equiped with working catalyst system

BTW whats the point of these discussions? Does anyone here actually know main culprit of wankel engine poor performance at low load? I´m just sick of all that marketing crap
Here is one solution to your bsfc dilema.
http://www.rotaryeng.net/RX8-TC-eng3.html
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Old 11-01-2011, 10:22 AM
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Originally Posted by Roaddemon
Here is one solution to your bsfc dilema.
http://www.rotaryeng.net/RX8-TC-eng3.html
stuff like that is the perfect example of : works on paper but totally impossible (or should I say impractical?) in real life.
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Old 11-01-2011, 10:40 AM
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Originally Posted by nycgps
stuff like that is the perfect example of : works on paper but totally impossible (or should I say impractical?) in real life.

kinda like hybrid tech. The cost negates the mpg increase. Unless you travel 20k /year for 10 years.
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Old 11-01-2011, 11:09 AM
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Originally Posted by Roaddemon
kinda like hybrid tech. The cost negates the mpg increase. Unless you travel 20k /year for 10 years.
But even then, you'll be replacing batteries...
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Old 11-01-2011, 11:17 AM
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Why would replacing batteries be a problem?

There are hybrid systems that only use a tiny battery in their system, and there are hybrid systems without batteries at all.


Agreed, replacing an entire floor of Lithium batteries is not exactly financially doable, and is another of the reasons I call the Prius a terrible way to do a hybrid.
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Old 11-01-2011, 11:27 AM
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Originally Posted by RIWWP
Why would replacing batteries be a problem?

There are hybrid systems that only use a tiny battery in their system, and there are hybrid systems without batteries at all.


Agreed, replacing an entire floor of Lithium batteries is not exactly financially doable, and is another of the reasons I call the Prius a terrible way to do a hybrid.

I also read a small fender bender in a Prius can cost thousands $ to repair because of the delicate nature of the Hybrid design. Not to mention special rescue equip needed to cut someone loose from prius wreck to avoid electrocution of first responders. Precious moments could be lost in fatal accident rescues.
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Old 11-01-2011, 11:50 AM
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I have to restrain myself to avoid discussing a hybrid method/idea that uses existing technology, add minimal weight to a car, and the majority of the cost and weight is just the electric motor itself.

I'm hoping I can get to the point of testing out the concept before someone else thinks of it. At some point I'm probably going to have to pay for a patent search.
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Old 11-01-2011, 01:00 PM
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Originally Posted by RIWWP
Why would replacing batteries be a problem?

There are hybrid systems that only use a tiny battery in their system, and there are hybrid systems without batteries at all.


Agreed, replacing an entire floor of Lithium batteries is not exactly financially doable, and is another of the reasons I call the Prius a terrible way to do a hybrid.
To keep my point simple and avoid a rant. my point is only that batteries are expensive. If you can resolve the expense, weight, and reliance on the hybrid system (the ability to disable or remove it without turning the vehicle into a pile of scrap) then I'm sold, and anyone else in their right mind should be to. If you want more mileage, replace it, if not, then suffer by paying more in gas, but I don't want to be forced to replace expensive or proprietary parts.
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Old 11-01-2011, 01:10 PM
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100% agree.

Each of my two concepts have no stored power at all. If the car is off, the jaws of life can go munching through without any level of risk. Parts replacement would not exceed the normal expectations of any other "normal" car. For one, it can also be completely removed from the vehicle, and as long as the ECU tune is adjusted to compensate, the only impact is some loss of performance from reduced power delivery (and some gain from reduced weight, even if slightly). For the other, it would just be an increased level of highway fuel usage (and slight weight savings)

In theory, both concepts could be present in the vehicle with no appreciable weight gain more than either one by itself would have, as the weight gain is essentially still just the electric motor itself. One is fairly easy to test from a "garage lab", the other might need some more specialized hardware (though nothing existing factories don't already have).

Last edited by RIWWP; 11-01-2011 at 01:18 PM.
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Old 11-01-2011, 03:23 PM
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Originally Posted by 999miki
The problem with cat converter, in the way Mazda research paper described it, lies in to cold EGTs for proper function of cat. Why is there cat in the first place when such engine can operate with much lower HC and CO emissions than conventional RE is beyond me
It is basically impossible to meet emission standards without a catalytic converter. The new federal standards are extremely tight. Hardly any pollution can come out of the tailpipe at all. This can't be done without a cat. The only other solution Mazda had back in the day was the thermal reactor, an emissions technology that was also employed on piston engines back in the 70s.

It must be in something that every car must be equiped with working catalyst system
Even though a rotary engine produces less NOx emissions than a comparable piston engine, the HC and CO emissions are high. It needs a catalytic converter... the oxidation process is very important. The cat on the Renesis used an HC trap to hold pollution as the engine warmed up.

BTW whats the point of these discussions? Does anyone here actually know main culprit of wankel engine poor performance at low load? I´m just sick of all that marketing crap
A lot of it has to do with the flame propagation in the trailing part of the combustion chamber. Due to the squish flows (concentrated pockets of mixture). This has been a problem since basically day 1. Another issue is flame quenching. Basically, the flames from the leading and trailing plugs collide with each other prematurely and you get a large unburned area. The revised engine geometry in the protype engines is supposed to help this.

There are also the normal issues with atomizing the fuel and other such things that affect piston engines.
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Old 11-01-2011, 04:23 PM
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Originally Posted by arghx7
It is basically impossible to meet emission standards without a catalytic converter. The new federal standards are extremely tight. Hardly any pollution can come out of the tailpipe at all. This can't be done without a cat. The only other solution Mazda had back in the day was the thermal reactor, an emissions technology that was also employed on piston engines back in the 70s.
hoho thermal reactor. oh no u didn't say that.

but someday, I think we might have to "go back to this wonderful technology" , Thermal reactor is pretty good at lowering emission and it will last virtually the life of the car.

Exhaust restrictions? robbing power? who cares? thx to clueless politicians and tree huggers who has no idea what science is all about. They just want/give less emission at all cost. even it might be impossible. we might not be able to get more than 50 hp in 10-20 yrs anyway.


A lot of it has to do with the flame propagation in the trailing part of the combustion chamber. Due to the squish flows (concentrated pockets of mixture). This has been a problem since basically day 1. Another issue is flame quenching. Basically, the flames from the leading and trailing plugs collide with each other prematurely and you get a large unburned area. The revised engine geometry in the protype engines is supposed to help this.

There are also the normal issues with atomizing the fuel and other such things that affect piston engines.
I hope so, it's been 20 something 30 years since the last major geometry changes.

Last edited by nycgps; 11-01-2011 at 04:30 PM.
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Old 11-01-2011, 09:10 PM
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use natural gas for fuel?
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Old 11-01-2011, 09:48 PM
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Originally Posted by arghx7
It is basically impossible to meet emission standards without a catalytic converter.

in the US it is impossible. the emissions regs mandate a cat.
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Old 11-02-2011, 10:31 PM
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I'm not sure exactly how this myth got started, that somehow a rotary doesn't need a cat and only has one due to some arcane rule.

The catalytic converter was an emissions and fuel economy breakthrough for the rotary when it was adopted in the days of the 12A. The problem with a thermal reactor is that it requires a rich mixture and high exhaust temperature to operate. Running a rotary without any exhaust aftertreatment system at all (no cat, no thermal reactor, nothing) is IMPOSSIBLE to pass emissions standards, even ones from 10 years ago.

Mazda has discussed this extensively in a paper they published 30 years ago. You can PM me if you want to learn more...
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Old 11-03-2011, 04:37 AM
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Old 11-03-2011, 04:42 AM
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Originally Posted by arghx7
I'm not sure exactly how this myth got started, that somehow a rotary doesn't need a cat and only has one due to some arcane rule.

The catalytic converter was an emissions and fuel economy breakthrough for the rotary when it was adopted in the days of the 12A. The problem with a thermal reactor is that it requires a rich mixture and high exhaust temperature to operate. Running a rotary without any exhaust aftertreatment system at all (no cat, no thermal reactor, nothing) is IMPOSSIBLE to pass emissions standards, even ones from 10 years ago.

Mazda has discussed this extensively in a paper they published 30 years ago. You can PM me if you want to learn more...
like zoom said, it's totally impossible in the US, you need a cat to pass, no matter how clean your tailpipe is.

not to mention, even pistons engine not gonna pass emission w/o a cat.
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Old 11-03-2011, 04:47 AM
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True that mate..

All CATS here too, one "good thing" I guess is no authority here monitors or tests owners car emissions at any stage of it's life.
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Old 11-03-2011, 09:48 AM
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Originally Posted by arghx7
I'm not sure exactly how this myth got started, that somehow a rotary doesn't need a cat and only has one due to some arcane rule.

..

i said nothing of the kind and it is not some "arcane" rule. US Federal emissions regulations mandate a calaytic converter. Even if a piston or rotary engine could be made to meet emissions regs with nothing or a thermal reactor or a great big blue snookery zu they would still have to run a catalytic converter because the regs say so. Unless they wanted to spend the time and money needed for lobbying to get that law changed to allow an alternative.
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Old 11-16-2011, 08:29 AM
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Originally Posted by olddragger
use natural gas for fuel?
Crack it into Methanol.....
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Old 11-16-2011, 09:17 AM
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Originally Posted by zoom44
i said nothing of the kind and it is not some "arcane" rule. US Federal emissions regulations mandate a calaytic converter. Even if a piston or rotary engine could be made to meet emissions regs with nothing or a thermal reactor or a great big blue snookery zu they would still have to run a catalytic converter because the regs say so. Unless they wanted to spend the time and money needed for lobbying to get that law changed to allow an alternative.
But it could be a really tiny one with big holes and little substrate
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Old 11-16-2011, 03:49 PM
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touche
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Old 11-17-2011, 04:51 PM
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Originally Posted by RIWWP
I have to restrain myself to avoid discussing a hybrid method/idea that uses existing technology, add minimal weight to a car, and the majority of the cost and weight is just the electric motor itself.

I'm hoping I can get to the point of testing out the concept before someone else thinks of it. At some point I'm probably going to have to pay for a patent search.
If only there was some long cylindrical metal (or carbon fiber) object in the car that could hold windings, so they would be spinning inside some form of tunnel or partial tunnel.....
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Old 11-17-2011, 05:19 PM
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If only...
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Old 12-01-2011, 08:08 AM
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another one: http://smh.drive.com.au/motor-news/r...130-1o64h.html
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Old 12-01-2011, 10:48 AM
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Originally Posted by foo77
Except the Shinari concept is for the Mazda 6, not a RX model.
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