Fuel Injection Question

I'm trying to get a better understanding of fuel injection systems that are used on the parallel valve Lycoming 180hp IO-360 engines with vertical updraft installations.

Airflow Performance offers two different AFP installation kits for their fuel injection system. One specifies using the primer ports and the other fuel injection port in the cylinder head. Fuel Injection directly into the cylinder would seem like the most efficient method. Using the primer port sounds like a compromise kludge.

Can someone provide some insight on how fuel injection with the ECI and Superior new clone engines is implemented. Is there an injector at each cylinder?

What function does the spyder (looks like a carburetor but has tubes running from it to the cylinders) perform. Am I confusing multiport vs. single port injection?

Mattituck discounts the Precision system quite a bit. Is the Precision fuel injection just a non certified version of the Bendix fuel injection or are they two different companies?

Fuel Injection

I think that you have confused a few things here. The Airflow Performance system is essentially the same as Bendix. Precision is the company that now makes the Bendix system (and have re-engineered it to some extent). All these systems are continuous flow systems that pour a continuous stream of fuel into the inlet port (not directly into the cylinder). Some cylinders do not have an "injection" port drilled, so the primer port can be used. It doesn't really make much difference to the end result. Most Superior or ECI cylinders have both ports drilled (and usually plugged). So whether you call it a kludge or not, all of the systems work in the same way. The injector body (the thing that looks a bit like a carb) attempts to measure the mass flow of air entering the engine, and schedules the appropriate quantity of fuel to be sent to the injectors. Fuel quantity is regulated by the injector body by changing fuel pressure - that is why many fuel flow gauges are pressure gauges marked in gallons per hour. The spider is the really only a way of splitting off 4 smaller pipes from the larger feed pipe from the injector body (it does also incorporate a low pressure shut off valve).

So, Airflow & Bendix are very similar and are multi port systems, I'm not aware of any single port systems. They are both continuous flow systems that regulate fuel pressure to control fuel quantity. There are no electrons involved in either, just a pair of expensive diaphragms (and associated valves). There are some good explainations of how the system works on the net, just have to google for the right thing.

Yours, Pete

Fuel Injection

Awesome answer there Pete...

Just FYI "newsum", I have an Aiflow Perfomance fuel injection system fitted to my Superior 360. I can confirm for you that the standard Superior cylinder has both the Primer and Injector ports ready for use and both are simply blanked off with plugs. Installation of the kit I purchased from AP was simple and I think you will find that there are plenty of happy pilots out there flying with this straight forward kit. Customer service has also been good and they will answer any questions you have, but my recommendation would be to go with the kit that mounts in the Injector Ports.

Mike

Fuel Injection

Lycoming has an outstanding training guide and CD on this subject. It would take about an hour to go through it. It is pricey, but I purchased it for Firebird Aviation anyway. Education is part of our free services to the RV community.
This training guide will remove all mysteries of the RSA system.
Anyone stopping by my shop at the Mineral Wells Airport, Texas is more than welcome to use it.
If you are interested in what a Superior IO-360 installation looks like, check out FirebirdAviation.com, and click on Rebirth of an RV-4.
Darrell

Good information! Thanks to all for your feedback on my question.

Maybe this is a dumb question, but I'm still learning about aircraft engines. What do these primer and/or injection ports on the cylinder look like? Doug's got a ton of pictures of building his ECI engine at http://www.vansairforce.net/eci/FlashEngine.htm. Can somebody point out the ports on one of those pictures?

Thanks,
Dave

Injection/Primer ports

Pick a cylinder - any cylinder, and look on the left-hand side just around the corner from the Rocker Cover. This is where the Intake Manifold is and if you were to look up inside you'd see the Intake Valve. On the casting of the cylinder, drilled into the intake wall are two holes that are tapped to receive pipe fittings. The top one is for the Injector and the bottom one is for the Primer. Normally the cylinder comes with a pipe plug in each of these two holes that you simply remove with a 3/16" Hex Wrench if you need to fit an Injector or Primer Nozzle.

Easy huh?


Mike

Ah, I get it now. I thought these ports went right into the cylinder. You're saying they go into the intake port. That makes sense. Thanks.