Water Injection and EMU?
 

Hey guys, I am thinking about getting water injection for my 1991 Greddy Turboed Miata with an Emanage Ultimate and Custom Intercooler. How would I hook it up? Would I just run a single from my greddy presure sensor to the water injection kit? Where are you guys putting your tanks at or are you using the stock windshield washer fluid tank? Thanks.

put the tank in the trunck so you have more range you can either switch via the greddy or just use a pressure sensor if you want variable DC then you will need a HSV. Wich would take a modified injector signal to be effective still i wouldn't spray until atleast 6 psi depending on your IC etc. And depending on your power gaols i would go 10-12% of your totall fuel potential with WI, with about a 30% mix of methanol.

Mine is autocross only, so I am using the windshield washer tank. In a hundred mile freeway criuse, not boosting much, I used three quarters of it. For track or daily driver a bigger tank is better.

I am running the Snow Performance (colorado company) Stage 1 boost cooler set to come on at 4.5 PSI using a 60ml/min nozzle. No intercooler yet. Spraying just before the dummy throttle body on my Supercharged setup.

No dyno numbers since the install, and I will have other changes as well before I get back to the dyno, but ... the exterior of the intake manifold is much cooler FWIW.

You will want to get a high speed valve and run it off the EMU's additional injector output. Then you have fully programmable progressive WI on a 2D map. Easy breezy lemon squeazy.

And perhaps there's a way to run WI off a 3D map that I'm unaware of.

sure all you need is pressure input then you can do DC vs rpm and pressure the same as we do on MS. I am not sure the emu can do that but it would be worth looking in to.

I don't have the EMU software on this computer, but I don't recall being able to choose IAT as the load axis. However, obviously you can choose MAP, and a 2D table of MAP vs RPM is pretty damn good, and better than nothing. Start at like 7 psi or so, and use your fuel map as a base, and basically just multiply each cell by 10% to get a 1:10 ratio of water to fuel.

The EMU can do a variable DC output on only two things:
1- It can rescale a variable DC input, but not by RPM or MAP, only a fixed scale (worthless)
2- It can generate a variable AFM output based on RPM & MAP. This would work if you retain the stock AFM.

The solution might be the sub-injector map. This gives you a full RPM/MAP table and is independent of the main injector maps. The only possible hitch would be that the period of this output varies with RPM, so you'd need to verify that whatever device you're driving will operate over a fairly large range of input cycle times. The "high speed" valve might do.

that is exactly what we are talking about.Joe

Then it's a no-brainer. Connect the valve to one of the un-used injector outputs (remember, the injector output driver is a switched ground, not an active high) and in the Parameters -> I/J tab, set the first "Type" parameter for that channel to "Sub I/J" and set the second "Type" parameter to "RPM" which will time it to the crank, rather than one of the main injector channels. (I believe that the firing order on the main injectors switches to full batch fire at some point in the load tables- I've got the diagram at home.) If you chose output A or B, ensure that JP 19 or 20 are set correctly (1-2).

Then on the "Map Select" tab, enable the "Sub I/J" map.

Now open up the "Sub I/J" map and select either PSI or VE, depending on what you're comfortable with. PSI is a more commonly used unit, but the MS crowd have been trained to think in VE. Populating values into the map is going to involve a knowledge of system pressure at the pump, nozzle size, and guesswork.

You can now go to the Logger and enable Sub I/J as a logged parameter to watch it go.

If you need a switch closure to turn on the pump when approaching boost, use the Aux output map. (page 42 of the EMU operating manual) This map drives the "VTEC" output wire (pin 14) to +12 when on. Use this to operate a relay that supplies power to the pump. Set it to turn on a few PSI below boost, so it's primed and ready when you cross over and start squirting.

Sounds fairly easy. Anyone have a link to a "high speed valve" that would be suitable for this application?

dont start to early esp if you have an IC spraying below 3 psi is not good for plugs.

aquamist 806-244
expensive :mad:

WOT says DevilsOwn will have one soon.

I sort of grasp the concept of this water injection thing you guys keep talking about. Help me out on something. Do you need to regulate the flow bassed on rpm or load? Could this be done by regulating the motor rpm? Or are you PWM modulating a small solinoid on the pump's outlet? If you want to control the motor's RPM there's a few inexpencive ways to do it I can walk you thru.

With the standard progressive systems, water is injected at a fixed rate based on manifold pressure, without regard for RPM. Technically, it would be better to have the water injected at a rate based on both PSI and RPM, and the technique described above accomplishes that.

Assuming the use of a high-speed water valve, you're not really modulating anything, you're just opening the valve for a certain amount of time every revolution, just like you do with the fuel injectors.

The Devil's controller, lacking the valve, attempts to vary the RPM of the pump motor by using PWM. This works, but it's not the most elegant solution. I think the "killer app" would be to use the valve and control it with the same box (the EMU) that's controlling the injectors. The amount of water injected can be very accurately controlled relative to the fuel in this case.

One piece of data that we would need to discover is an accurate understanding of the valve's response time for the off-on and on-off transitions. What Greddy refers to as "lag time" in their EMU software.

That's what modulation is. Pulsewidth modulation (PWM). on-off-on-off... That's what injector drive is. Would the system need a dampener like a fuel pulsation dampener? I guess the lines themselfs would absorb some of it. The reason I ask is there always a better/less expencive way to design something. If it was worth my while I might look into designing something so I'm just getting a feel for what it is your after in water injection and alot of you are using it so it might be worth my while developing a better system.

From Aquamist:
Basically it's a stainless steel high z fuel injector

PWM generally refers to the use of a switched voltage to simulate an analog signal, using variable duty cycle on a fixed period. Class-D audio amps, switching power supplies, solid-state motor speed controllers and lighting dimmers, that sort of thing.

Fuel injectors drivers aren't attempting to simulate a variable voltage, they're just turning the injector on and off. So I don't really consider injector drivers to be PWM circuits any more than my annoying nephew who loves to toggle the lights in the room off and on.


Hmm.... Assuming one cycle per crankshaft revolution, that works out to 4800 RPM maximum. No good.

I guess on a 1.8 engine you could time the Sub I/J to one of the main injector channels and that would give you one cycle per two revolutions, which would drive the HSV at roughly 60Hz at redline, which would work. I really need to find that damn document that shows the injector timing on the 1.6...

Fuel injection is width bassed on load and frequency bassed on rpm. I'm not trying to argue I'm trying to help you understand what PWM is. You are correct in saying class-d amps, dc motor controllers, smps, use PWM. Fuel injection is another. If you've looked at an injector signal on a scope you can see what I mean.

http://en.wikipedia.org/wiki/Pulse-width_modulation


On the waterspray... Are you trying to find a solinoid valve that will open/close like a fuel injector once per revolution? Does the water need to be controlled as accuratly as the fuel injectors need be? Why not just use a fuel injector for the water?

bringing this back into action as id love to read more on it......

More about Lazzer & I debating the finer points of digital modulation theory? :gay:

nah just wondering if you could get some diagrams of how you would set it up Joe ;) hehehe, that will be my my next move after i get all the turbo stuff worked out ;)

"digital modulation theory" :gay:

I'm the master of PWM. What do you need? I can draw up something. Motor control? Solinoid control?

Oh! Which reminds me... I found the perfect little solinoid valve for the junkyard do-it-yourself'er. You can find on a Chevy Lumina van that has the airpump built in for filling tires. Open the rear cargo door and check the left rear compartment behind the controll panel for the pump. There's a spiffy little high pressure solinoid back there. :bigtu: I'll post a pic.

I think 10hz would be more then enough. Put the solinoid in the trunk and the line to the intake will 'buffer' the pulsation.

What can I say? He's still wrong. PWM attempts to emulate an analog signal using only a digital switch. Fuel injector drivers, by comparison, are not trying to feed a variable voltage to the injectors to hold them in an intermediate-state condition, they're just turning 'em on and off. The components may look similar, but the application defines the circuit. :rolleyes:

The only way I'd call a fuel-injector driver a PWM circuit would be in a peak-hold application, and only if the "hold" condition was achieved by high-speed switching of the driver, rather than with a resistor.

And what the heck is a solinoid, anyway... :gay:

"solenoid" :vash:

Whos wrong? I'm wrong? Read up on PWM. Fuel injectors are driven with a PWM signal. The width is proportionate to...? Engine load?

once again Lazzer talks out his ass

Lazzer, I'll agree with you that the concept between fuel injector driver and pulse width modulation are similar. However, the applications are completely different.

PWM is a method digital regulation to achieve "analog-like" results. Most common application is voltage control (dimmer or motor speed control).
A fuel injector is simply turning on and off.

Impress me. Design a simple circuit for M2CupCar that will regulate the start up voltage to his high draw cooling fan (30A).
The device needs to begin at 50% duty cycle, ramp up over 3 seconds, then remove itself from the fan circuit. No fan shut off regulation required.

God damn lazzer why cant you play nice for a fucking minute without pissing everyone off?

Sweet shit man you dont know everything. ANd the stuff you know is probably wrong.

Do you consider .0001ohm of a mosfet "removed" or do you need a bypass relay to activate once 100% is reached? The program I use to draw schematics doesn't have any pwm driver IC models. One I use is the 3525. There are a few ways to do this. If you want exactly 3 seconds you'll need a pic processor otherwise I'll go with an RC network similer to a throttle ramp in motor control. Will that be enough for you?

Why is it always Ben and Loki that challange me? I don't understand why you guys get pissed off when I try to help someone understand something.

http://i196.photobucket.com/albums/a...h_MVC-002W.jpg

Back when I was screwing around designing a speed control for my EV I wondered how well the circuit would work for audio as a "class-d" amplifier. In the video it's just one mosfet being used LC coupled to the speaker. The scope is showing the signal at the speaker and is far from ideal. I wasn't building an amplifier after all. I was building a speed control for a 144vdc series wound motor.

Attachment 216004

There's the switching side of the fan controller. Ignore the stator winding. That's the only motor model I have.
I guess I can use a dual op-amp for osc and pwm. bbl

Sounds like your after the same system i'm running.

I've got the DO base system, running to a Aquamist HSV that i'm controlling via the sub I/J map.

Been running this system for a while now, nothing but praise for it.

The beauty of this system is you can control the HSV and water level by 0.5% DC.


Here's 1 of my sub I/J maps i was running as an example:

http://i32.photobucket.com/albums/d4...lip0001-24.jpg


Cheers
Mark

I want the ramp up circuit completely removed from the fan's current path in all ways, once the ramp event is concluded. 3 seconds was a number I pulled out of my ass. It doesn't have to be exact, nor does it have to be exactly regulated.

I also forgot to mention, the parts need to be cheap, and the circuit easy for a novice to build. I have one in mind; I'd be interested to see what you can come up with.

And I can't see you schooling Mr. Joe Perez, Ph.D on circuit theory.

Attachment 216002

When the switch is closed Q1 will conduct charging C1 thru R1. The voltage on C1 will be sent to the 3525 input to begin 0-100% pwm. When the switch is opened Q2 will discharge C1 to 'reset' the timing portion of the circuit. R2 and R3 set the trip point for the comparator which will be used to activate a bypass relay. I believe the 3525 uses 0-2.5v = 0-100% so the comparator should be adjusted for >2.5v trip in order to activate after 100% pwm is obtained. I'm not going to illustrate a complete schematic or values. That involves time I'm not being paid for. If you use an opamp for your osc/pwm I suggest you use another totempole for the mosfet gate drive.

I wasn't aiming on "schooling" anyone. I'm just saying injector drive is PWM. Hence the "duty cycle" term used in fuel injection. The duty cycle is the "on" state of the pulse or "pulse width". The ecu adjusts (modulates) the pulse width bassed on engine load and that, by definition, is pulse width modulation. PWM

Hey, no fair posting a useful, relevant answer that actually addresses the matter we've all been blithly ignoring! :bigtu:

Those without an emu can build a pwm bassed control ran off a map sensor couldnt they?

I guess I know they could but would they want to.

The master eh? :rly:
Some master you turned out to be...
good luck finding that pic man, last i checked Chevrolet didn't make a Lumina van, IDK, maybe your program can draw one up. You seem to do alot of searching/copy and pasting to sound smart... try google for once and see what a lumina looks like, and maybe then you can post something smart.
Trust me when i say, you're not helping anybody yet. Just because you read something on another forum, or on Wikipedia, doesn't mean that its the only right answer. Quit debating and pay more attention to your new master, Joe.
You've been schooled.

I think there is a simpler solution, if you run a vacum line to your container, then the more you boost the more you build pressure in the container pushing water/methanol to your nozzle. A check valve can be used so water only goes in the intake manifold when boost is present and not vac. Container must be pressure tested before trying this method but there are no electronics nor moving parts that will fail. Just an input...

probably not enough pressure available, but theres a good idea there. Just would need a pressure transducer and a variable relay of some sort to a motor. Keep in mind im a ME and hate electronics.

no offense mouglie, im all for ripping on lazzer, in fact its replaced my full time job, but that was a late hit.

Mougile actualy i believe there was such a thing as a chevy lumina van back in the early 90's they where called safaris i believe But IDK for sure.

:owned:

hahaaa... my bad...

I forgot about this. Here's it is. It has a metal body and looks like the fittings GM used can be removed. I'm just keeping an eye out for usefull junkyard parts that would be common. Like a Lumina Van. Attachment 215853

:inout: