Actual Rotary Displacement Request

[t_g_farrell]

Originally Posted by PhillipM

It's not that because for taxation reasons it gets classed as a 2.6L anyway...

Wow! That does suck then.

Rice, that was a great demonstration with the pics.

[My5ABaby]

Originally Posted by PhillipM

It's not that because for taxation reasons it gets classed as a 2.6L anyway...

Of course Mazda says it's a 1.3L. It would be stupid for them to call it anything else from a marketing standpoint, regardless of taxation.

I don't want to buy a 3.9L or 2.6L engine that makes 146hp. I want to buy a 1.3L engine that does.

[Barry Bordes]

Yes Peter I agree that it would take three revolutions of the eccentric shaft to have all faces of the rotor see fire.

Following that logic the other trochoid shapes would need four or five revolutions to show all faces and hence we would have to multiply them by 4 or 5.

I am saying that in all of these shapes that the displacement is the volume of the largest cavity created by the two corresponding surfaces (actually 4 counting end plates).

This would hold true for a two-stroke and a four-stroke also.



As an example the caliber of this revolver doesn't change if it holds different numbers of slugs. It is still a 357.

[RICE RACING]

Barry, ALL of the total sum faces fire once in 1080 degree's, nothing more nothing less.

Like I tell my students, you need to take time out and see the pictures, if you don't get it at first do not worry you are not the first and not the last to get confused on how internal combustion engines work.

2 stroke
4 stroke
Wankel

Its pretty simple really.

[RICE RACING]

For EVERYONE remember this.

In 360 deg
ALL CYLINDERS in a 2 stoke fire once! no matter if its single or a V16!

In 720 deg
ALL CYLINDERS in a 4 stroke fire once! no matter if its a single or a V16!

In 1080 deg
ALL faces of a rotary wankel fire once! no matter if its a single rotor or a 4+ rotor!

Which ever formula you decide to use in your PISTON applications you need to know which EQUIVALENCE displacement to use (2 stroke, 4 stroke or wankel) there are no aftermarket ECU's set up to run the true Wankel cycle or count the individual rotor faces based of its ACTUAL cycle (which is only 1080deg, nothing less)......... so you just need to know how a motor works and apply the other piston engine formulas to the wankel as appropriate (as I showed all of you)

[Libor]

Originally Posted by RICE RACING

there are no aftermarket ECU's set up to run the true Wankel cycle or count the individual rotor faces based of its ACTUAL cycle

Peter, I was curious about something. Would there be any benefit in engine control with ECU of such abilities? Like better fueling of individual chambers?

[RICE RACING]

Originally Posted by Libor

Peter, I was curious about something. Would there be any benefit in engine control with ECU of such abilities? Like better fueling of individual chambers?

There are some of us who are using this kind of bespoke *aftermarket* true rotary ECU and have been doing so for a long time!

Yes there are major benefits!
Mazda racing ECU's and stock ECU's are of this type 1080 deg true Wankel cycle, it is the only way to truely look at the engine.

Otherwise you do need to do alot of conversions to adapt all the other ECU's, not to hard to do, but most dont get it, especially when you are looking at things like control of injector opening and closing degree's etc.

[Barry Bordes]

Originally Posted by RICE RACING

Barry, ALL of the total sum faces fire once in 1080 degree's, nothing more nothing less.

Like I tell my students, you need to take time out and see the pictures, if you don't get it at first do not worry you are not the first and not the last to get confused on how internal combustion engines work.

2 stroke
4 stroke
Wankel

Its pretty simple really.

Actually example (3) (shown below) would take 1440º and

example (4) would take 1800º to complete all faces of its trochoid shape.

Different rotor/stationary gear ratios would be used to accommodate the 4 in 3 and 5 in 4 trochoid mesh.

Barry

[RICE RACING]

I am ONLY refering to the Wankel Rotary I pictured and as we all use, drive and modify

Nothing else

[scotty305]

Interesting question, Barry.

Originally Posted by RICE RACING

There are some of us who are using this kind of bespoke *aftermarket* true rotary ECU and have been doing so for a long time!

Yes there are major benefits!
Mazda racing ECUs and stock ECUs are of this type 1080 deg true Wankel cycle, it is the only way to truly look at the engine.

Otherwise you do need to do a lot of conversions to adapt all the other ECUs, not to hard to do, but most don't get it, especially when you are looking at things like control of injector opening and closing degree's etc.

Mazda stock ECUs are only capable of measuring 360 degrees of eccentric shaft rotation; since the trigger wheel is mounted on the eccentric shaft it cannot discern the difference between one rotor face vs the other three. As far as the ECU is concerned, the rotary may as well be a two-cylinder two-stroke that displaces 1.3L per 360 degrees.


In a similar fashion, you could compare a 1.3L two stroke piston engine to a 2.6L four-stroke piston engine... both ingest the same amount of air in 720 degrees, but the 1.3L two-stroke occupies less space and will weigh less assuming similar materials are used to build both engines. Is this starting to sound familiar? If I'm not mistaken, the two-stroke should have less torque at low RPM greater fuel consumption than the four-stroke. I'm not an engine expert (rotary or piston) so please correct this if I'm wrong.

[RICE RACING]

Originally Posted by scotty305

Interesting question, Barry.



Mazda stock ECUs are only capable of measuring 360 degrees of eccentric shaft rotation; since the trigger wheel is mounted on the eccentric shaft it cannot discern the difference between one rotor face vs the other three. As far as the ECU is concerned, the rotary may as well be a two-cylinder two-stroke that displaces 1.3L per 360 degrees.


I'm not an engine expert (rotary or piston) so please correct this if I'm wrong.

No mate they use 1080 in programming and can measure it with a 360 wheel on the crank



You may not know where each individual rotor face is but that is not an issue so far as knowing the actuall Wankel Cycle and when to trigger things.

[Monkman33]

Guys, displacement by definition is the volume displaced by one revolution of the crankshaft or e-shaft in this case. doesn't matter if it is 2 stroke, 4 stroke, or not.

You guys are all going off on this "when does it ignite, and when does it do this or that?" It's all moot.

total volume displaced over 1 crankshaft revolution = Displacement. It is consistent across the board. There is no Mazda conspiracy to hide its actual displacement. A 6.0 liter engine is a 6.0 liter engine, whether its 2 stroke or 4. You can't use the "Getting back to face 1" argument due to the trochoidal nature and the 3:1 ratio. If you do use this argument, then you have to divide the final result by 3 because of the 3:1 ratio.

Now, what is the one consistent thing in all the engines? output RPM. Displacement is based on 1 of these revolutions. So any other attempt to define definition by more than 1 revolution is incorrect. 1 revolution is the consistent factor across the board. Te reason racing bodies use a multiplier is to even the playing field just like they do for 2-stroke engines. The advantage a 2 stroke has is that is happens to fire its full displacement per revolution, just as a rotary does, where as a 4 stroke only fires half of its displacement per revolution.

Don't confuse revolutions of the rotor versus the crank/eshaft. You'll end up chasing ghosts.

[RICE RACING]

It's not a argument, its FACT! ALL INTERNAL COMBUSTION ENGINES (except the rotary!) are rated on ONE CYCLE OF WORK FOR THE COMPLETE ENGINE.

Mazda conveniently choose to not rate the whole engine, if you or others can't get that then you need to move onto another area of interest I suggest, one you can understand

The Wankel Rotary is a 1080deg cycle, nothing more nothing less!

You btw f*** your own argument cause a 4 stoke is NOT rated after only 360 degrees! cause it HAS NOT COMPLETED ITS CYCLE OF OPERATION! it is rated ONLY AFTER 720 degree's (suck sqeeze bang blow) it only SUCKS once in 720 degree's! and ALL piston faces are counted to rate the displacement of the whole engine! not 1/3rd of them, or 2/3rd's of them! but ALL OF THEM!......... The irony is only in the rotary world where people want to only count 1/3rd of the combustion faces and rate it as a 2 stroke engine, but its NOT! its a wankel and thus they only want to count one face (which misses out 2/3rds of the rest of the engine). if only you could do this on a BDC built half bridge!!!! then when it drops an apex seal on each rotor he can then tell you its only a 2 stroke engine like people in this thread and the other 2 apex seals and four combustion faces are not required LOL!!!!!!!!!!!

[j9fd3s]

Originally Posted by RICE RACING

No mate they use 1080 in programming and can measure it with a 360 wheel on the crank



You may not know where each individual rotor face is but that is not an issue so far as knowing the actuall Wankel Cycle and when to trigger things.

ah yes, good point! one of the rotary ADVANTAGES is that each stroke is 270 degrees instead of 180 like a piston engine.

you are wrong though, piston engines suck all the time

mike

[RICE RACING]

Just remember

Each engine is only *honestly* rated for displacement AFTER (ALL OF ITS ELEMENTS) have completed one cycle of work.

Elements = ALL individual combustion faces
Cycle = defined by power pulse (or simply spark firing) *remember suck sqeeze bang blow*

It's not a hard concept to fathom honestly ......... some always struggle cause they don't know how the 2 storke or 4 stroke or Wankel actually work though!

Define the cycle!
Count the faces!
There is your answer for displacement!

Equivalence (like I mentioned in my second post) can be used to compare the 13B to other non wankel cycles (as defined by time to displacement), IE displaces 1308cc in 360deg or 2616cc in 720deg, but it only does its wankel cycle in 1080deg which my friends = 3924cc in 13B form, nothing less!