*EDIT*
Photos added as new post at end of thread & Now has a low water warning on screen.
*EDIT*

Hey all...

Just to let you know about the water injection controller I am making - bit of information and how to use it.

It is designed to work with just about any water injection pump that uses a motor (ie. diaphragm pumps, impellor pumps).

A decent pump and nozzle is needed, the autospeed GMH pump and spraying systems co. nozzle is ideal, for more hardcore turbo applications a shurflow pump and spraying systems nozzle can be used. It also has an output for a solenoid check valve for applications where the nozzle is mounted after the throttle body.

I am also designing a unit to drive extra injectors (better than a crappy microswitch, and mappable too!) for the turbo guys.

Both will be priced around the $200 mark.


Information:

Traditional water injection systems used nothing more special than a boost switch to turn on a pressure pump at a specified manifold pressure. This works crudely, as at the turn-on point, the water/fuel ratio is close to ideal, but as the boost starts to rise, it drifts away from the ideal mixture. It doesn't take into effect the fact that it is 5 degrees on a freezing cold morning (when it wouldn't be needed) or 40 degrees at full load up a hill.

This is where the Water Injection Controller comes in - the car's ECU knows what the intake temperature is, it knows the load of the engine, ignition advance and intake airflow, it uses this to control its injector duty cycle. It does this better than any boost pressure switch, intake airflow or map sensor. So why reinvent the wheel? Use the car's ECU to do the thinking for you!

The controller looks at the injector pulse width, (0-100%) and turns it into 250 load points, giving you a 0.4% resolution. The user then sets the duty cycle (PWM 0-255 = 0-100%) of their water injection pump at each one of these load points using the three front panel buttons (up, down and enter) and the backlit 2 line 16 Charactor alphanumeric LCD screen. As the duty cycle of the injectors change, the controller reads the appropriate map point and controls the pump as neccesary.

To make setting the maps a breeze, a minium pump setting is also stored, so that when you increment a map point from zero, it immediatly jumps to the minimum pump setting (no pumps produce a usable spray at low output). The previous map point is tranferred to the next one (if the next point is zero only to avoid deleting the users prior settings) making a curve easy to set.

To program, the ENTER button is held down when power is applied to the unit - it enters the programming mode. There is also a 'factory reset' mode that deletes all of the settings in the unit (hold down all three buttons on power up). The buttons are locked out in normal usage, to avoid accidentally changing any settings.

In normal use, the unit displays the current injector pulse duty cycle in both percent (and the current map point it is reading), along with the pump duty cycle in both percent and its current PWM setting on the point in the map.


Display List

Power up (engine not running)

Water Injection
Controller V2.50


Engine Running (when engine stops goes to above screen)

FUEL 86% (216)
WATER 75% (191)

Programming Mode

Program Mode
(+) Increase

Program Mode
(-) Decrease

Program Mode
(OK) Save Value

Min Pump PWM
0 (0%) (Use the +/- Enter buttons to set)

Saving PWM Data!

SET 0/250 (0%)
Set PWM 0 (0%) (Use the +/- Enter buttons to set)

Saving SET Data!


Factory Reset

ERASING XXX/252

DONE!


Comments/suggested improvements welcome!

Sounds impressive Heath.

On most of the commercially available units I've seen, the pump is capable of 150psi presumably to allow for good atomisation. Is the Autospeed GMH pump that you recommend also capable of these sort of pressures?

The $200 cost is for the control unit alone so what other hardware would be required for a complete system?

When will the final version be ready for sale? I'd like to get some form of water injection in while the weather's hot!


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Go Heath! Looks like good stuff. Cant wait to see how it goes when you finally get yours supercharged.

Sooo what's the benefit of one of these? What exactly do they do? What are they supposed to improve?
Are they for NA or boosted cars?
Spraying water... where does the water come from? Where does it go?

The GMH pump is 38 Psi, but the nozzle gives good atomisation at this pressure (nozzle has a 22psi check valve - its working pressure is around 20 psi upwards)

The other designs use a spearco pump (basically a diaphragm pump for portable water system pressurisation - for boats/caravans etc).

The control unit will be *around* $200, probably closer to $150-175 actually. The case is a diecast box, and its quite small. PITA to design a PCB for, I don't think I'll keep with this but I need to put it in some sort of box at the moment :P

The first version wont have an external LCD, I'm having enough fun fitting an LCD with a backlight, a 40 pin microprocessor, a handful of buttons and the PWM circuitry into a box that measures about 1 inch tall, 2.5" wide and 5" long. Its a very tight squeeze, the LCD is sitting on top of the chip :doubt:.




Sounds impressive Heath.

On most of the commercially available units I've seen, the pump is capable of 150psi presumably to allow for good atomisation. Is the Autospeed GMH pump that you recommend also capable of these sort of pressures?

The $200 cost is for the control unit alone so what other hardware would be required for a complete system?

When will the final version be ready for sale? I'd like to get some form of water injection in while the weather's hot!


.

Sooo what's the benefit of one of these? What exactly do they do? What are they supposed to improve?
Are they for NA or boosted cars?
Spraying water... where does the water come from? Where does it go?
have a read through this post...

http://aussiemagna.com/forums/showthread.php?p=640301#post640301

cheers,
.wook

Bit more progress. Finally settled on the chip that is being used, its got far fewer pins, and less eprom space, so only 128 map points (0.8% resolution) but it makes the board smaller and cheaper, its quicker to program in your load points and it isn't using a sledgehammer to crack walnuts. Code size is under 2K so no point in having 8K of program space and another 16 unused IO ports :doubt:

Controller will handle a 10A pump with ease, its easily mountable in the glovebox, and has a clear plastic lid that the LCD can be seen though. All of the buttons are inside the case, so no accidental bumps change the settings, and the LCD screen can be relocated to somewhere else if you so desire (it uses 16 pin IDC headers, easy to extend with ribbon cable).

Uses screw-down terminal strips for your power, injector feed and motor output - only 6 wires! (+/- ign, injector feed + and -, motor + and -). Motor output is fused, so no nasty suprises either, and it also has an LED to show it is recieving injector pulses as well (so polarity is immediately obvious)

Getting closer, just designing a board that looks OK (since it will be visible) and has adequate heat dissipation.

Cheers
Heath Young

Heath, I have access to a laser cutter if you need help with making the perspex top. Also it could have writing/frosting to cover the pcb.

Here's an Autospeed article on water injection. It's from 1999 but the theory still applies.

http://autospeed.drive.com.au/cms/A_0115/article.html


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does anyone know when using a supercharger does the water injection jet go after or before the charger?

does anyone know when using a supercharger does the water injection jet go after or before the charger?


It can go before or after but before is better.


.

why is it better to put the injector jet before the charger?

heath, you using a atmel or PIC?

i've wrote a program similar to yours for a PIC, just never got a hold of the nozzle or pump.

mine was also designed to read of a carby TPS.

PIC - Amtel is nice but expensive. Pic is good because there is a lot of support for them, pleanty of compilers etc.

This is a revision of an old design I made years ago for an insane Saab turbo I once owned - ran up to 25 psi boost on occasions. (It was a fully mappable management system for the turbo, water injection and extra (4) injector drivers). Its pretty stripped down now, no need for boost control or injector drivers. It ate too many gearboxes, and being a lowered compression FWD turbo, power came on in a rush, so it had a nasty tendancy to steer itself into gutters :doubt:

Cheers
Heath Young

Another update - settled on a box (finally) - Bulkhead mountable plastic with a clear plastic top to view the LCD. (120 W, 70 D and 30 H). Uses screw-down terminals, so nice and easy to connect to.

I solved the heat issues with the voltage regulator (LCD backlight was consuming 100ma) and added a status LED to make the unit easier to install - LED is tricolour, red for power, yellow for valid pulses detected and green for pump running. This could be remotely mounted on the dash etc. if so desired - only takes 3 wires.

PCB boards are on their way (after 10 iterations!) - initial boards will not be silkscreened, I know what goes where (the board is TIGHT, especially with using single sided boards and through-hole componentry... Surface mount would be nice but meh - my eyesight isn't what it used to be.

Couldn't fit a fuse in the case, there just isn't room. Easy enough to install an in-line fuse.

I also recieved my VDO pump and spraying systems nozzle to play with - I will have to do some proper volume measurements and spray quality testing.

The mosfets I will be using for the motor control are pretty nice - lowest RDS I've seen - 5.3 mOhms(!) so very little heat generated. The totem pole driver is now behaving nicely as well.

The mosfets are rated at a crazy 160A each (read the fine print and you work out that the package is only capable of 75A (the legs on a to-220 package make fairly good fuses at this current) - Power handling will allow a pretty large pump (at roughly 20A) to be used with ease.

The boards will probably go through a few more design revisions due to how cramped they are...

Some minor bugs in the software have been ironed out as well.

A more solid price of $150 seems achieveable for these units, bringing the total cost of a fully programmable water injection system to around $300 with a decent pump.

Cheers
Heath Young

OK some photos...

I messed up this board iteration, the connector for the LCD should be on the right, so it is connected with a ribbon cable... Sigh. Still works though.

The LED won't be used to free up the board space - the voltage reg now has a heatsink (it was getting a little too hot doing its thing.

BUT - this is the same basic design and case as the production version. Its nice and small, fits perfectly inside the glovebox or centre console... (120W X 50D X 63H)

The mapping is still being tested to see it all works, but no major bugs found as yet.

I will post up some pics when I am happy with the final production boards.

Cheers
Heath Young

A more solid price of $150 seems achieveable for these units, bringing the total cost of a fully programmable water injection system to around $300 with a decent pump.

Cheers
Heath Young

Sorry mate for being a nub...

Will you be producing? As i am very interested (I will buy one) if you see positive results.

Cheers

Tristian

Impressive stuff Heath!

Yes I will be producing them - I'm now hopefully on the last iteration of the PCB boards (famous last words for me) - I put some text on the boards that I forgot I needed to reverse (typical).

Boards are still handmade. At the moment. The heat issue has been ironed out (I ended up using a heatsink for the voltage regulator - it was within operating specs before, but if you cant hold it for 20 seconds without having to let go, its too hot (rule of thumb? :D )

I have another board to etch tonight and populate tomorrow... (With the LCD screen in the right place this time)

Cheers
Heath Young

well as i said.

You are obviously doing this for benefits. So put me down as a customer.

Ready to purchase.


Just trying to show how interested and serious i am

Cheers

Tristian

There is an article on autospeed today all about water injection which is great for describing the pros/cons. http://www.autospeed.com/cms/A_107970/article.html Should we just copy and paste the article or get permission? I am sure Julian Edgar would be interested/impressed by heaths controller.

Thats a pretty good article actually - it addresses a lot of points / requirements of a water injection system.

I have now gotten to the final prototype board stage, it only needs a few components moved 1 mm or so around for adequate clearance (the crystal for example makes it hard to remove the PIC for a firmware update).

I am in the process of writing this up as an article for Silicon Chip magazine, with Jaycar Electronics probably having the kit rights (like most SC stuff) - so you will be able to build your own. :)

Cheers
Heath Young

Minor update - firmware redesigned again (now up to version 3.2(!) - yes, thats 32 iterations) :nuts:

Now detects 100% duty cycle properly, reads the maps nicely, you can adjust the PWM minimum trip point independently of the MAP values (which update dependently on this), you can adjust the minimum PWM output with the pump running - so you can see straight away on a bench (rather than mapping it at idle or something like that).

Getting closer guys... Now building the second prototype to send to Silicon Chip...

Cheers
Heath Young

Wow, i hope this will be relatively easy to setup/tune. Sounds like its going to be a great product though.

Heath, how long do you reckon before this is ready for sale?



.

Its coming soon (yeah so is christmas) - Seriously though I have been busy at work so the development has stalled a little, the final PCB is basically ready for production.

AFAIK all of the little bugs (bar one) have been ironed out - for those who are wondering what the last bug is - it is a small problem with the IC dumping a full high pulse for 0.1s when the PWM turns off. It doens't do anything to affects its operation though.

Real time mapping is not going to happen either, the steps are too fine, so even at a consistent RPM/Load the duty shifts up and down rapidly as the computer adjusts the mixtures - or maybe my car has issues :doubt:

I can probably supply the assembled and mounted board for those who are interested soon, the problem is that I am currently moving house so the workshop resembles downtown Bazra on a bad day :(

Cheers
Heath Young

Hey Heath how's the WI controller coming along? Any closer? :D

I've been rather busy with other projects, but autospeed is basically following my design path (ulka pump and inverter) - I might shoot them an email with some information on my design, might be of some interest to them...