WTB first gen RX-7
03-04-04, 06:58 PM
#27
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The engine will start easier it will be be internally balanced so it will run smoother and it will idle smooth at a lower RPM> I posted a topic in tech that explains the idle and cruise problem that they had in the past amd Mazda's solution for it.
It was also explained easlier that the inertia of the out flowing exhaust and the in flowing intake will cause a seperation.
In further thought a one way valve may be required on the intake to enhance the performance .
Cheers
Ken McKenzie
It was also explained easlier that the inertia of the out flowing exhaust and the in flowing intake will cause a seperation.
In further thought a one way valve may be required on the intake to enhance the performance .
Cheers
Ken McKenzie
03-04-04, 07:30 PM
#28
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sounds good. I think a one way valve will be needed, I find it hard to belive that the inertia of the intake on an n/a engine would be enough to counter the pressure from the exhaust.
anyway, it sounds pretty cool to me, when will you have one running?
anyway, it sounds pretty cool to me, when will you have one running?
03-04-04, 08:32 PM
#30
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listen...this guy is trying to explain to everyone what he is working on. and all you can do is tear his ideas apart and and tell him he's wrong. if you think this is bullshit then don't ****** read it. nobody is trying to sell anyone anything. keep your harsh negative comments to yourself.
03-04-04, 08:38 PM
#31
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Starapex, with all due respect... Your understanding of mazda's rotary is so flawed I don't even know where to begin. That's cool that you designed your own rotary engine when you were 18 back in 1960 or whatever, but when you come on here and say stuff like "mazda is incompetent, I know all about rotaries and will provide a solution for all it's shortcomings... blah blah" I get offended. Mostly, because I think you have no idea how modern rotaries operate but are somehow not aware of this fact. I think the principles and problems you describe may have applied 40 years ago, but even the rotaries in the early 70s were a DRAMATIC improvement over the original wankel engine mazda received to begin development from. It barely begins to compare.
I've read your 'writeup' in the tech section, but I don't think you'll find too many people who will agree with your assessment. Especially anyone with actual experience in tuning and building rotaries.
I'm sure this sounds kind of hostile, and it is, at least to a degree. I think it's great that there are people out there like yourself coming up with ideas, but coming on here bashing mazda and not providing proper facts, or even any evidence at all for your claims, will get you this sort of criticism.
I've read your 'writeup' in the tech section, but I don't think you'll find too many people who will agree with your assessment. Especially anyone with actual experience in tuning and building rotaries.
I'm sure this sounds kind of hostile, and it is, at least to a degree. I think it's great that there are people out there like yourself coming up with ideas, but coming on here bashing mazda and not providing proper facts, or even any evidence at all for your claims, will get you this sort of criticism.
03-04-04, 10:39 PM
#33
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There is no intent to bash Mazda. I am impressed with their skill and the quality of the product they make.
I do have a problem with people who say that innovation is ok as long as it is within established guidelines.
Prior to finding out about jerking, and bucking problems that take place in the Suzuki motorcycle and the NSU spyder I was under the opinion that what I have previously tried to explain in this thread should be known in the industry and that they were intentionally keeping modifications to the rotary to conform with established guidelines. With this thought in mind I labeled the industry as Goofs or Goons.
THIS KNOWLEDGE IS ONLY A COUPLE WEEKS OLD
The problem is inherent in an engine with the exhaust port in a position that has the apex seal slide over the hole when a leading surface is in the compression stroke. The power stroke pushes against the rotor and holds the gears against the leading edge of the stationary gear. When the apex seal slides over the exhaust port the pressure is released and the compression pressure pushes the rotor back and against the trailing edges of the stationary gear.
THE ABOVE DOES NOT APPLY TO THE MAZDA ENGINE
Mazda moved the exhaust port to open earlier to a position so the exhaust is released before the compression stroke has started.
Half measures avail us nothing in fact they make matters worse. Moving the exhaust port a couple of inches ahead will give a longer power stroke but the kick received from the compression stroke when the pressure is released is greater.
None of the manufacturers took the time to understand the problem so none of them recognized that the solution is to move the exhaust port to the minor axis.
On Sunday I took a damaged housing from a RX-7 and noted that the exhaust flange allows for a hole to be drilled through the flange and into the race in the ideal place. SO I DID IT. All I need to do now do the same to a good housing and then get a steel plug cast and chromiumed to insert into the old exhaust port and the engine can be assembled.
The engine will look exactly the same but it will have a power stroke for the complete eccentric shaft revolution.
THe power stroke will push the rotor to do the compression. The Apex seals will have continuous pressure against the housing race supplied by the power stroke the exhaust stroke and the compression stroke.
There is an car austion next Tuesday and I am going to see if they have a RX7 to auction.
I am presently building a rotary engine and I kid you not it is complicated. It is not only making the parts it is understanding the characteristics of metals. and it is all trial and error.
Cheers
Ken McKenzie
I do have a problem with people who say that innovation is ok as long as it is within established guidelines.
Prior to finding out about jerking, and bucking problems that take place in the Suzuki motorcycle and the NSU spyder I was under the opinion that what I have previously tried to explain in this thread should be known in the industry and that they were intentionally keeping modifications to the rotary to conform with established guidelines. With this thought in mind I labeled the industry as Goofs or Goons.
THIS KNOWLEDGE IS ONLY A COUPLE WEEKS OLD
The problem is inherent in an engine with the exhaust port in a position that has the apex seal slide over the hole when a leading surface is in the compression stroke. The power stroke pushes against the rotor and holds the gears against the leading edge of the stationary gear. When the apex seal slides over the exhaust port the pressure is released and the compression pressure pushes the rotor back and against the trailing edges of the stationary gear.
THE ABOVE DOES NOT APPLY TO THE MAZDA ENGINE
Mazda moved the exhaust port to open earlier to a position so the exhaust is released before the compression stroke has started.
Half measures avail us nothing in fact they make matters worse. Moving the exhaust port a couple of inches ahead will give a longer power stroke but the kick received from the compression stroke when the pressure is released is greater.
None of the manufacturers took the time to understand the problem so none of them recognized that the solution is to move the exhaust port to the minor axis.
On Sunday I took a damaged housing from a RX-7 and noted that the exhaust flange allows for a hole to be drilled through the flange and into the race in the ideal place. SO I DID IT. All I need to do now do the same to a good housing and then get a steel plug cast and chromiumed to insert into the old exhaust port and the engine can be assembled.
The engine will look exactly the same but it will have a power stroke for the complete eccentric shaft revolution.
THe power stroke will push the rotor to do the compression. The Apex seals will have continuous pressure against the housing race supplied by the power stroke the exhaust stroke and the compression stroke.
There is an car austion next Tuesday and I am going to see if they have a RX7 to auction.
I am presently building a rotary engine and I kid you not it is complicated. It is not only making the parts it is understanding the characteristics of metals. and it is all trial and error.
Cheers
Ken McKenzie
03-05-04, 05:58 PM
#36
Got Boost?
Whoa there captain... call me silly, but I think your a bit confused on your explination. In your second post you go through an explination that we've all gone through in our minds. You explain exactly what the rotary engine does, then...
This just doesn't make any sense. Each rotor rotates 120* per shaft revolution, so I get the three power strokes in three shaft revolution parts. Its where you say that there are Three surfaces "working" at the same time. This doesn't compute...
When one rotor face sparks (say TDC-compression), there will be an apex seal directly at 6 o'clock(facing TDC-intake/exhaust), opening the exhaust. Therfore, each rotor only would only have one working surface at a time, so on a two rotor engine only 2 working surfaces.
Yes what I think you are describing does give 360* power stroke length, but you are wrong on the duration of power stroke for mazda's rotary, the power stroke is around 240* or around 2/3 of a eshaft rotation. BDC though is at 270* eshaft rotation after TDC, so by lengthening the power stroke to 360* is just plain silly. Maybe you can clairify?
Anyway, if you look at the torque produced as a function of engine rotation, you relize that very small amouts of power are wasted by opening the exhaust ports at 240*. IIRC more than 80% of the energy is produced in the first 100*-150* of eshaft rotation. By opening it early(240* instead of 270*) the residual heat and pressure aid in expelling the spent exhaust gases. It was in the 1860's or so that this was found to be more efficient, and powerful in the boingers of the time. Its as true today (even on a rotary) as it was back then.
At first glance I thought you were describing a miller cycle rotary, but that would place the exhaust at 5 o'clock(like normal), and the intake at 8-9 o'clock. Which mazda has tried IIRC.
The engine completes three power strokes in three shaft revolutions and one rotor revolution therefore it completes three four stroke cycles or the total of twelve cycles.
Three surfaces work at the same time therefore three strokes take place in 3/4 of a shaft revolution. Six strokes take place in 1 1/2 shaft revolutions and twelve strokes take place in three shaft revolutions.
How is that for a start?
Three surfaces work at the same time therefore three strokes take place in 3/4 of a shaft revolution. Six strokes take place in 1 1/2 shaft revolutions and twelve strokes take place in three shaft revolutions.
How is that for a start?
When one rotor face sparks (say TDC-compression), there will be an apex seal directly at 6 o'clock(facing TDC-intake/exhaust), opening the exhaust. Therfore, each rotor only would only have one working surface at a time, so on a two rotor engine only 2 working surfaces.
Your study will confirm that each rotor will have a continuous power stroke for a 360 degree eccentric shaft revolution. Mazda only has a power stroke for slightly less than half of that.
Anyway, if you look at the torque produced as a function of engine rotation, you relize that very small amouts of power are wasted by opening the exhaust ports at 240*. IIRC more than 80% of the energy is produced in the first 100*-150* of eshaft rotation. By opening it early(240* instead of 270*) the residual heat and pressure aid in expelling the spent exhaust gases. It was in the 1860's or so that this was found to be more efficient, and powerful in the boingers of the time. Its as true today (even on a rotary) as it was back then.
At first glance I thought you were describing a miller cycle rotary, but that would place the exhaust at 5 o'clock(like normal), and the intake at 8-9 o'clock. Which mazda has tried IIRC.
Last edited by fatboy7; 03-05-04 at 06:00 PM.
03-05-04, 10:37 PM
#37
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I get lost in the maze when I try to understand the single rotor engine if I do not have the functioning pieces before my eyes.
To understand the engine one must realize that for every 30 degrees of driveshaft revolution the rotor turns ten degrees
The process that takes place when the driveshaft rotates 90 degrees after ignition is
on one surface The first third of the power stroke is completed.
On the surface ahead of the power stroke the second third of the exhaust stroke is completed.
On the surface behind the power stroke the last third of the intake stroke is completed.
This all takes place at the same time.
This ninety degree drive shaft rotation must take place twelve times to see all the strokes in the single rotor Wankel engine.
The cavity on the surface behind the power stroke enlarges one third during the aforesaid ninety degree process.
Maximum displacement is reached on the opposite side from the driveshaft lobe and an apex seal when they point in the same direction.
The apex seal that started on the minor axis directly opposite the power surface slides to the point on the housing where the intake port should finish.
In obtaining a 360 degree power stroke I am choosing to compress the exhaust to assist the end of the compression stroke
I am extending the power stroke and reducing the exhaust stroke by the same amount.
I therefore only have a two thirds of the exhaust stroke functioning.
I am working on a nine sided rotary piston engine and today I succeeded in machining eighteen 1/16" by 3/16" slots in the sides of it so I can use Mazda side seals.
The reason I utilize first generation Mazda rotary engine parts is they are in the public domain and I do not want to give Mazda the opportunity to restrict me.
I will be out of town until the 8th of March.
Cheers
Ken McKenzie
To understand the engine one must realize that for every 30 degrees of driveshaft revolution the rotor turns ten degrees
The process that takes place when the driveshaft rotates 90 degrees after ignition is
on one surface The first third of the power stroke is completed.
On the surface ahead of the power stroke the second third of the exhaust stroke is completed.
On the surface behind the power stroke the last third of the intake stroke is completed.
This all takes place at the same time.
This ninety degree drive shaft rotation must take place twelve times to see all the strokes in the single rotor Wankel engine.
The cavity on the surface behind the power stroke enlarges one third during the aforesaid ninety degree process.
Maximum displacement is reached on the opposite side from the driveshaft lobe and an apex seal when they point in the same direction.
The apex seal that started on the minor axis directly opposite the power surface slides to the point on the housing where the intake port should finish.
In obtaining a 360 degree power stroke I am choosing to compress the exhaust to assist the end of the compression stroke
I am extending the power stroke and reducing the exhaust stroke by the same amount.
I therefore only have a two thirds of the exhaust stroke functioning.
I am working on a nine sided rotary piston engine and today I succeeded in machining eighteen 1/16" by 3/16" slots in the sides of it so I can use Mazda side seals.
The reason I utilize first generation Mazda rotary engine parts is they are in the public domain and I do not want to give Mazda the opportunity to restrict me.
I will be out of town until the 8th of March.
Cheers
Ken McKenzie
03-06-04, 08:07 AM
#38
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In looking at the previous post to my last one I see the attempt to understand the engine in 120 degree eshaft rotation segments. This will only provide a scrambled view of the stroke functions.
There is an overlaping of strokes that can only be understood in one third of each four cycle stroke segment, and the ninety degree e shaft rotation segment.
Three strokes take place in 3/4 of a e shaft revolution
Six strokes take place in one and a half e shaft revolutions.
Twelve (Four cycle) strokes take place in three revolutions.
This is the critical difference that were not seen by the worldwide rotary engine industry up to this time.
One quarter revolution of the e shaft produces one third of a four cycle stroke on each surface of the rotor.
Cheers
Ken McKenzie
www.starapex.com
There is an overlaping of strokes that can only be understood in one third of each four cycle stroke segment, and the ninety degree e shaft rotation segment.
Three strokes take place in 3/4 of a e shaft revolution
Six strokes take place in one and a half e shaft revolutions.
Twelve (Four cycle) strokes take place in three revolutions.
This is the critical difference that were not seen by the worldwide rotary engine industry up to this time.
One quarter revolution of the e shaft produces one third of a four cycle stroke on each surface of the rotor.
Cheers
Ken McKenzie
www.starapex.com
03-06-04, 05:40 PM
#40
Got Boost?
In looking at the previous post to my last one I see the attempt to understand the engine in 120 degree eshaft rotation segments. This will only provide a scrambled view of the stroke functions.
You are looking at 90* rotor segments(since 90* is the length of one cycle on a given rotor face), which is the same as me looking at 270* eshaft segments (90* rotor motion divided by 120* degrees of rotor motion per 360* of eshaft rotation <90/(120/360) = 270>) All the research papers I've ever read in SAE and other journals refer to degrees of eshaft rotation, so thats what I go by. By this reasoning there are 1080* in a complete cycle. Usually its easier to look at one rotor face at a time, because the faces of the rotor don't ever interact, thus they have individual P-V diaagrams.
Pick a standard frame of reference, and you'll make alot more sence. Right now, I can't connect the dots. For instnace you say...
Three strokes take place in 3/4 of a e shaft revolution
This is the critical difference that were not seen by the worldwide rotary engine industry up to this time.
In obtaining a 360 degree power stroke I am choosing to compress the exhaust to assist the end of the compression stroke
I am extending the power stroke and reducing the exhaust stroke by the same amount.
I am extending the power stroke and reducing the exhaust stroke by the same amount.
Last edited by fatboy7; 03-06-04 at 05:42 PM.
03-08-04, 08:50 PM
#41
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Thanks for taking the time to explain I believe that we are not that far apart.
QUOTE
Usually its easier to look at one rotor face at a time, because the faces of the rotor don't ever interact, thus they have individual P-V diagrams.
The fact is the faces of the rotors do interact
Up to this time most thought is about individual strokes and the understanding the process of their functions.
What I am presenting is the division of each stroke into three parts.
In one revolution of the e shaft the you will have a three thirds power stroke and a one third exhaust compression stroke that provides a spring like assistance to the compression stroke and also assists the next power stroke. the surface following has a two thirds exhaust stroke and a two thirds intake stroke. The following surface has a one third intake stroke then a full compression stroke.
You must ignore the intake and exhaust locations that we know today as they have not been placed in the correct positions.
While I was away I reread The Wankel Rotary engine A history by John B. Hege
I read the book about a year ago and I knew it all form other books I have studied.
This time I got a lot of information that I didn't know.
They have information and a picture of Mazda's new Renesis engine. I note in the picture that they have moved the exhaust port sufficiently ahead to take advantage of an additional one third power stroke displacement.
They could not do this with ports on the periphery because of the interaction of the compression face due to pressure loss as the apex seal crosses the exhaust port.
The side port does not allow for all the exhaust to escape and therefore traps and compresses it against the housing providing sufficient pressure to balance or assist the compression stroke.
The problem with their configuration is they cannot position the intake port in the correct position.
Information taken from the book in my own words.
Intake ports came together in a two section plenum chamber. The divisions in the chamber made good use of the strong compression waves that are characteristic in the intake of a Wankel engine to achieve a ram effect between the rotor banks. Mazda called the effect. “Dynamic Supercharging”
Why has nobody questioned ? Why are we having strong compression waves in the intake of a Wankel engine?
ANSWER
After the intake stroke is complete the rotor does one third of the compression stroke while the intake port is still open.
This simple fact when it is known along with what Mazda doing with their exhaust in the Renesis is going to push the piston driven engine out of existence.
I have a picture following that shows maximum displacement on both sides of the engine and the position that I believe the exhaust and intake ports should take
This picture shows the front rotor with the intake stroke just completed and the compression stroke starting.
Cheers
Ken McKenzie
QUOTE
Usually its easier to look at one rotor face at a time, because the faces of the rotor don't ever interact, thus they have individual P-V diagrams.
The fact is the faces of the rotors do interact
Up to this time most thought is about individual strokes and the understanding the process of their functions.
What I am presenting is the division of each stroke into three parts.
In one revolution of the e shaft the you will have a three thirds power stroke and a one third exhaust compression stroke that provides a spring like assistance to the compression stroke and also assists the next power stroke. the surface following has a two thirds exhaust stroke and a two thirds intake stroke. The following surface has a one third intake stroke then a full compression stroke.
You must ignore the intake and exhaust locations that we know today as they have not been placed in the correct positions.
While I was away I reread The Wankel Rotary engine A history by John B. Hege
I read the book about a year ago and I knew it all form other books I have studied.
This time I got a lot of information that I didn't know.
They have information and a picture of Mazda's new Renesis engine. I note in the picture that they have moved the exhaust port sufficiently ahead to take advantage of an additional one third power stroke displacement.
They could not do this with ports on the periphery because of the interaction of the compression face due to pressure loss as the apex seal crosses the exhaust port.
The side port does not allow for all the exhaust to escape and therefore traps and compresses it against the housing providing sufficient pressure to balance or assist the compression stroke.
The problem with their configuration is they cannot position the intake port in the correct position.
Information taken from the book in my own words.
Intake ports came together in a two section plenum chamber. The divisions in the chamber made good use of the strong compression waves that are characteristic in the intake of a Wankel engine to achieve a ram effect between the rotor banks. Mazda called the effect. “Dynamic Supercharging”
Why has nobody questioned ? Why are we having strong compression waves in the intake of a Wankel engine?
ANSWER
After the intake stroke is complete the rotor does one third of the compression stroke while the intake port is still open.
This simple fact when it is known along with what Mazda doing with their exhaust in the Renesis is going to push the piston driven engine out of existence.
I have a picture following that shows maximum displacement on both sides of the engine and the position that I believe the exhaust and intake ports should take
This picture shows the front rotor with the intake stroke just completed and the compression stroke starting.
Cheers
Ken McKenzie
03-08-04, 10:06 PM
#42
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Sorry I haven'tr figured out how to post a picture.
What I want you to visulize is a rotor in the housing with the e shaft lobe and an apex seal on the major axis during the power stroke.
The opposite side will be at maximum displacement and the intake port should be closed by the apex seal just past it.
The compression stroke starts from this position.
Cheers
Ken
What I want you to visulize is a rotor in the housing with the e shaft lobe and an apex seal on the major axis during the power stroke.
The opposite side will be at maximum displacement and the intake port should be closed by the apex seal just past it.
The compression stroke starts from this position.
Cheers
Ken
