New to forum / Custom WI system for AUDI

[simple]

Hello All,
I am new to this place. Have found it searching some info on W/I.
This place is great source of useful info!
My Location: Australia
Car: AUDI 1.8T Quattro B6
The reason for searching, I am trying to build a custom W/I system for my car. Still learning about it. My intension is to have a variable W/I with knock sensitive activation and self learning function.
I know that I am on a quest for the Holy Grail, but it is in my nature to explore (I lead R&D team at factory).

Val

:smile:

[Richard L]

It is a good idea. YOu need to find a good reliable knock signal or risk injecting too much water due to other engine noises at high RPM.

The holy grail is finding a true "knock signal", a "voice print" of your particular engine is necessary, may be require a high speed DSP (digital signal processing) chip to record and compare and filter out the background noise.

Good luck with your prioject.

[simple]

Thanks Richard,
I have parts already coming from different parts of the world. I will keep you posted on the progress.

[simple]

An update for those who interested

At this stage we are only testing the hydraulics, to get some data to refine electronic control module which is in drawings stage.
This is the pic of the one of the test set-ups



The pump is 5 L/m 160PSI. Happy workhorse



The jet we experimenting is agricultural 40 micron, low wear ceramic internals atomizing nozzle. Utilizes centrifugal force atomization principle. It has surprisingly stable atomization from 30-160PSI range. Picture taken at 160PSI



At this pressure it delivers 420 cc/m. And at 20PSI (min pressure) we get about 140cc/m.

We also need to try Aquamist jet, it has better adopted fitting. Just need to get my hands on one :wink:

[Richard L]

I am not sure how you are going to control the flow, If you vary the pump speed to vary the flow, please consider the following:

Your starting pressure = 30psi+ 20psi (assummed manifold pressure) = 50 psi to get a decent droplet side.
You final pressure will be 160psi-20psi = 140 psi

The actual pressure change is 50-140psi, approximately 3x.

Translate the presesure change to flwo change:

In order to double the flow, you need 4x the pressure. So you actual flow range is about +70%. Do you think it will be adequate for your application? Can you pump create more pressure?

If you put a 15psi checkvalve inline to stop the water from vacuum siphoning , your pressure span will be reduced further to 65psi to 125psi, giving you less than +50% increase between min and max!






Richard

[simple]

Hello Richard and thank you for the input.
I did not allow for boost back pressure ? my bad. At this stage I have two paths to go, it is a twin stage pump system to generate 250-280PSI or to have twin stage nozzle set up when second nozzle valve controlled and opened when first nozzle is maxed out.
Both ideas need to be tested for suitability and no so great.

On the other hand I plan to have accurate knock detection and water will be delivered and volume of water accurately calibrated JUST to suppress the detonation. Based on that I guess that my requirements for water flow range will be significantly reduced due to the fact that amount of water needed to be injected not proportional to RPM at given load.

I have come across a person in Canada who tested SS fuel injectors for 6 months in a solution of 50/50 water/meth. Both, fuel pump and fuel injectors have survive the test and in a good shape. This is something to test and consider as well.

I also was considering HSV you sell and constant water pressure. But I would prefer analogue water delivery to pulsed spray as I plan to inject water 50sm away from engine head and you may not get homogenised mix of water droplets and air.

I guess that truly Ideal set up would be to have 4 nozzles (one for each port) and each nozzle controlled by HSV and constant water pressure. Basically we have to copy fuel injection system. Than we can vary HSV duty cycle to deliver necessary amount of water. This set up will also allow you to deliver water to cylinders as needed due to the fact that not all cylinder knock when engine under the load. Some are more stable and need a lot less water added. This set up will use a lot less water as it will not waste any.
The problem here is the cost of HSV as you would need 4 of them.

Looks like I get carried away a bit. Sorry for the long post
:smile:

[Richard L]

Depending on the final specificationa, the capability required.

Progressive pump system analysised:
Apart from the limited dynamic range (unless you have a pump that can delivery between 50psi to 1000 psi), you will still fall short of the power range of an engine.

Progressive pump speed system is also quite slow to react to change fo transient load, for example: change up or down a gear could mean a change of delivery quantity of 1000rpm. A rotating mass (pump motor) will not be fast enough to react to this change. So you have one more things to consider if you want to go for a anaogue pump speed controller.

Pulsed delivery will not affect the engine dynamics that much, considering the engine only have one intake stroke per revolution (I think?). Since droplet size is a mixed bunch, smaller droplet to travel faster towards the throttle even it starts at the same point. So in real time, you have a continuous train of water droplets spread over the entire inlet tract.

I think you should really consided a system similar to the fuel injection system adopted by almost all car makers.


Richard

[simple]

OK, done some tests with fuel injector:



Injector is off 3.0L Turbo supra / V-shape (440cc).
Result is disappointing. Atomization at 140PSI is poor as you can see on the picture. It is more like jet spray rather than mist (comparing to previous agricultural nozzle).
Now I need some professional input from tuners here, do all injectors have that bad atomization?

[Richard L]

Almost all injectors have narrow angle and the atomisation is about the same. Theyarenot design to cool inlet air but aim at teh inlet valves (also requires cooling).

Richard

[simple]

Richard, can you post some specifics for HSV valve.
I wonder how I can drive it. I believe it has 250Hz max operating frequency.
I need to know what signal needed to drive (like square pulse) and what is recommended signal duration to operate it at 1% duty and 99% duty.
What is it? internal resistance, so I can work out power consumption. Also what is it?s inrush current (if know)?

Car specifics as mentioned before:
1.8L Turbocharged motor / 4 cylinder
Four inlet ports/ 3 intake valves per port.

Considering using one HSV to operate two M3 nozzles (mounted in common section of plenum)