According to this image at what point does the rotor start to compress the air volume?

About how high above the aux port?
or at what degree?

If some would like to take the image into paint and draw a line at that point it would be helpful, thank you.

 

AFAIK it is a simple answer, as soon as the tip of the rotor passes the dimple/peak in the spark plug side of the housing it starts its' compression "stroke" for the face just behind that apex seal.

While at the same time the face just ahead of that seal is is initiating it's expansion "stroke".

 

can somebody give me the actual # of degree, at which its stats reducing in chamber volume?

 

I have no idea. Go here: http://www.rotaryengineillustrated.c...ions/index.php and look at an animation of the combustion cycle.

A rotor has three faces/combustion chambers. One apex seal at either end.

When the AFT apex seal reaches the hole of the oil injector, THAT is where I think the compression STARTS for that face. That apex seal has just gone past the intake ports so the intake part is done at that time. And what follows intake? Compression.

I also looked in the FSM for a na engine and it says that the auxillary intake ports are closed at 70* ABDC. So compression should happen just prior to that or just after that *. I figure. Don't know. Got me. Look at the animation in the url.

http://www.rotaryengineillustrated.c...ession-ex.html

 

wel this is what i have come up with, so crrect me if im wrong, but the compression ration starts at maybe 90*ish

 

pretty cool picture you got there.

It helps a lot to put some abstract degree values into something more easily understandable.

 

Something like that.

http://www.rotaryengineillustrated.c...etary-m-2.html

This url above is the only one I could see the animation on. They have the aux ports highlighted a bit, and you can see where the rotor passes over that aux port and start compression. That's about as close I can give for an answer. Someone will come along sooner or later with a better pic.

 

looks like it starts when the LEADING end of the apex seal is in between the spark plugs

 

anyone know the actual #* at which it starts compressing?

 

Let's start by establishing the purpose for which you need to know this.

The first response you got, from RockLobster, was a perfectly intelligent, sensible, and i believe correct answer. Apparently it is not in the format that you are asking for.

Now, it seems no one has been able to give you this information in the way you're asking for it. Are you sure that whatever notation you're looking for is common? or used regularly in any fashion?

I think you need to explain what specifically you are looking for, and how you want it measured.

 

all im asking is according to the image and the mechanics of the rotary engine, at what TDC* does the rotor start compressing.

i dont have a motor apart in front of me to play with, so telling me that it happens when the apex seal is touching the first spark plug hole is helpful but i cant replicate it.

 

I think I got it but you have to bear with me because it does not come from 1 single reference publication.

According to Kenichi Yamamoto's book "Rotary Engine" In 1.4.2 Principles of operation; figure 1.28 and the accompanying paragraph, "The volume of the working chamber [the one on the intake stroke] gradually expands as the rotor rotates as illustrated by 2 and 3 and reaches the maximum volume at 4.

Now for those who don't have the book (I'm using a PDF version of it) figure 1.28 position 4 shows the rotor with one apex seal pointing straight down along with the lobe on the E-shaft pointing straight down. This would be Bottom Dead Center, correct? The intake port is still open slightly and doesn't close until position 5. Position 5 shows the intake port closed, but the e-shaft lobe is no longer at Bottom Dead Center, it has rotated further toward the exhaust port, or to a position After Bottom Dead Center.

Now, according to page 1-4 of the factory service manual the primary port on a 6 port non-turbo engine closes at 40 degrees ABDC (After Bottom Dead Center) and the secondary port closes at 30 degrees. (Aux port closes at 70 deg ABDC) On a 4 port turbo engine the primary port closes at 50 degrees ABDC.

So with all the ports closing ABDC, the working chamber is already going into the compression stroke because the working chamber is at its largest volume until it reaches Bottom Dead Center and anything after BDC begins the compression stroke.

Hope that all makes sense and answers the original question.