Maybe it's just me, but there seems to be some confusion on the net. i think i have this straight:

The air bleeds are the little plastic caps that always break. These are positioned under the fuel injectors.

The anti-afterburn system is regulated by an air solenoid and is powered by the air pump. This sprays additional air right at the fuel stream during a throttle slam to prevent the mixture from being too rich.

Assuming all that is correct, my question is: Do these two things have to do with each other? i mean, what do the air bleeds do exactly? i can't imagine they assist in atomization beyond what the injectors orifice disk does. do these two systems work together? Are the air bleeds "part" of the anti-afterburn?

Sorry to post this in the MS forum, but I think I’d rather ask you guys than the general clientele. I’ll move the post if anyone has an issue with it.

 

The air bleeds definitely help atomize the fuel better than just the injectors alone.

They are necessary on the rotary because there aren't any hot valves to spray the fuel at to help vaporize the fuel.

If you remove these bleeds, it can cause the engine to run poorly.

I'm not sure it has anything to do with the anti-afterburn stuff directly... I thought that was a separate system that adds more air to the exhaust not to the intake. I'm not sure though, most of the rotaries I've worked on have had emissions equipment removed.

Ken

 

ken,
logic would point to you being correct about the bleeds assisting atomization, but i just don't understand how they do it...they are plastic, so they clearly are not used to hold engine heat so supply the fuel a hot surface to vaporize on (which would make more sence to me). so their effectiveness must be in their "screen". it just seems odd that the tiny hole(s) in the injector orifice disk under a high pressure can't atomize fuel as well alone. thats like spraying a water bottle on a screen door to get smaller droplets...the only way i can think that would help is to have some air blowing on the fuel as well somehow. anyway, sorry about the rant, i tend to do that when i can't understand something concerning fluid flow.

 

If you look at the fuel injectors, they spray directly down into the port, kind of like the "air doors" in large commercial buildings.

The air bleeds catch the fuel and allow the airflow to pull it through the screen, atomizing it. It's the next best thing to injecting the fuel into a booster venturi for carburetor-like atomization.

And no, fuel injectors don't atomize very well at all in the absence of turbulent airflow. The bigger the injector, the worse the atomization. (And what do we have...) Really big injectors' patterns look more like open hoses than a mist of fuel...