Indepth study of WAI injection systems

[C6C6CH3vo]

Here is a study MIT did with direct injection under ultra high pressures using ethanol, they were able to triple the boost (50psi) on the gasoline engine. The text is advanced beyond the scope of this forum and I found it difficult to understand much of the math/formula's (some of you guys may understand), but the basic principle is reasonably understood and provides several additional facts to what we already know that were surprising, e.g. optimal antidetonant effects respective to injection and intake valve.

Another thing, methanol wasn't used due to it's toxicity so it really lacks any importance to the industry. It was however pointed out being superior to ethanol

Enjoy

http://lfee.mit.edu/public/LFEE%202006-01%20RP.pdf

[Richard L]

Post #1 has been updated.. (23rd December 2007)

More detail study of a water injection pump.
Indepth study of WAI injection systems

[Richard L]

Post #1 has been updated again.. (26th December 2007)

More detail study of a PWM valve system.
Indepth study of WAI injection systems

[SlowCar]

Richard, when you get time...will it be possible for you to make a video of a side by side comparison of PWM valve vs. Proportional valve action using a M15 or a M10 nozzle commonly used on Evos?

[Richard L]

I will certainly do it as soon as I get get a free day. I will also data log it to a chart.

I hope you are having a nice break.

[Richard L]

More updates in post #1 and post #2 done.

1. PWM valve and proportional valve difference (with pic)
2. Regulating pump pressure.

[Zeus]

...still holding out on direct port.

[PK3]

Very interesting thread. Has any body taken this stuff off the paper, out of the books, out of the lab and onto the track?

I Find my super doesn’t really linger at full boost for very long. Wonder if it really could fathom the nuances of the exact droplet sizes and the like.

Bottom line… using the best science here, does it make it faster and safer?

Regards, PK

[Richard L]

Originally Posted by Zeus

...still holding out on direct port.

I am working on it.

[Richard L]

Originally Posted by PK3

Very interesting thread. Has any body taken this stuff off the paper, out of the books, out of the lab and onto the track?

I Find my super doesn’t really linger at full boost for very long. Wonder if it really could fathom the nuances of the exact droplet sizes and the like.

Bottom line… using the best science here, does it make it faster and safer?

Regards, PK

One has to start from somewhere, theory based on with practical experience goes a long way. At present WAI technology is at the same transitional stage as carburetted engine to single point fuel injected engine.

Like anythime else, the knowledge and infomation is there and available - food for those inquistive minds.

[PK3]

Originally Posted by Richard L

One has to start from somewhere, theory based on with practical experience goes a long way. At present WAI technology is at the same transitional stage as carburetted engine to single point fuel injected engine.

Like anythime else, the knowledge and infomation is there and available - food for those inquistive minds.

Richard

Couldn’t agree with you more, proof of my interest is that I’ve read this 7 page post and links twice. As you know I’m toying with ideas that accumulated, might make for a setup better than most. (I come from a family of engineers (I’m not though)).

In fact, the prospect of a relatively resistance free CV made me dream a couple up, maybe using aeronautic principles to wedge a modified ball into somewhat inert “docked” position which wouldn’t ‘t require a full 20 psi to keep it there and out of the way.

But, is it worth it? What if, if for instance, half the beautiful shaped droplets wind up hitting the walls of the intake manifold and consolidate into worthless condensate like tears anyway.

Regards, PK

P.S. I’ volunteer my Porshe as a mule

[Richard L]

A CV that snaps only is quite possible - just design a gated valve with machanical hysteresis, similar to a tactile membrane switches. But with the availability of a solenoid valve, why bother.

Any metal based spring is subject to temperature influency, The switching point of the snap CV valve may differ greatly between 30C and -30C.

Drop dispersion should have taken place at the point of injection. Chances are droplets will have done most of its work done during this moment of impact. Any wetting surrfaces should have dried up similar to the action of a super poweful hair dryer.

Before multipoint injection was used, there are many cars that run on a single throttle located injector, I believe RX7 is amongst one of them.

[PK3]

Hello Richard

I agree with your principle about the solenoid being Ideal. Someone in this thread the brought up the issue of meantime between failure (MTBF?), Solenoid V. check valve.

As I think about though, assuming a solenoid is half as durable as an injector with far fewer cycles, ought to last the life of the car. it’s the circuitry to it which might be prone to failure.

As to droplet size and the like, I have ulterior motives. The easiest place for an injector in my car is to poke it straight into the side of my 4 inch round intake. From intricacies brought up here, I might be losing (allot?) by essentially spraying directly at the opposite wall of the intake tube.

On one of sub threads here a guy had a clever little setup that had the centered in the intake & angled to spray straight along with the air flow. I wonder if it was worth it in my case or a solution looking for a problem.

Regards,

PK

[Richard L]

If the correct solenoid valve is used, it should work for the life time of the car. Things to watch out for in chhoosing a solenoid valve:

1. Pressure limit
2. Flow limit
3. Continuous rating
4. Heat rise against "3" within a permissible max.
5. Fluid compatibility with seal
6. Fluid compatibility with wettwed metal parts

You will find the past premature failure is main due to mis-match. In this industry, there ara very few WAI manufactures perform proper test before launching a system. I would not take anyone of their advice too seriously - do your own research.

Only two years ago, WAI makers still using viton seals on their pumps even alcohol injection has been around for much longer than that. you cannot gauge MTBF value for compariring two different devices.

Droplet tranfer - think for it this way, when tyou inject 10% methanol to fuel at AFR 12:1. The actural mass ratio between methanol to air is : 120:1 - do you think 0.83% of maetanol has a chance of staying put for long along the inlet tract before it got sweeped into the combustion chamber? Having a wetted wall will help the next boost cycle before fresh methanol arrives at the inlet valves.

There are more important aspect of WAI require more detail study.

Abner is the person who uses a centrally located jet, good idea.