He is using a microprossor, which is really the only good way to do this. You can learn to use these processors too, but it will take a committment on your part. They aren't really all that hard. But if you're only focused on the automotive side, maybe this guy will sell you one of his.

 

don't know if I have time right now to learn how to program a microprocessor lol - might have to wait til the end of the year lol! I think that must be the only real way to do it!?

he has put up a schematic and wiring diagram....

I will try and contact him about it all... i'd need some basic instructions but would love to attempt it

i'd need to use a DC pump

 

I use a DC pump similar to this on my boat for cool misting. Mine is self-priming, meaning noisey. I use a simple mechanical pressure switch to regulate the pressure. Not what you're after, but I can vouch for the effectiveness of the pump.

 

I use a DC pump similar to this on my boat for cool misting. Mine is self-priming, meaning noisey. I use a simple mechanical pressure switch to regulate the pressure. Not what you're after, but I can vouch for the effectiveness of the pump.

Yeah well I think the easy idea for this whle thing would be to use a boost pressure switch to turn on the expresso pump and open a normally closed water solenoid (like used in hot water systems) this would prevent siphoning/pressure leak down etc. The good thign about the expresso pump (piston type) is tht it produces pressure very quickly.

I will do a lot more research to figure out the best way to get progressive control of water injection, I think it has to be with a DC pump and a microcontroller to be able to have it versatile and adjustable!

Thanks for the help. I really want to learn more about the electronic side of these sorts of things. my daily driver is a car with pretty cool engine management, I once read all the patent information on the designs and looked through the wiring diagrams, so many foreign concepts.

 

I will do a lot more research to figure out the best way to get progressive control of water injection, I think it has to be with a DC pump and a microcontroller to be able to have it versatile and adjustable!

I agree. You might want to just leverage off this other guy's work. If you want to learn the UP stuff, there is lots of help available here.

 

Oh, one more thing. Many of the microprocessors (microcontrollers) have PWM built right into the devices, so you don't need a separate chip. Just some buffer/driver electronics.

 

I agree. You might want to just leverage off this other guy's work. If you want to learn the UP stuff, there is lots of help available here.

Thanks for making me welcome, maybe after I get permission from the owner Ill get step by step help recreating a microcontroller for myself (and maybe taking a different route without the LCD) based on that guys schematic!

so my understanding is approximately
- analog signal (0-5v) goes into analog to digital converter
- once in digital the microcontroller interprets the digital waveform and responds to it with a relevant pwm signal which gets sent to a motor driver
- the motor driver drives the DC water pump

is that basically the overall gist of it?

 

Hey, I just noticed, this isn't a custom design, you can freely buy the board, and then see if you can get his code. Check this out:

http://www.pololu.com/catalog/product/1373

BTW, I'm not sure his design is even using PWM. He might just be using on/off control. But, if you want to improve the design, you can still go down that path. Also, the PWM you will use will be much slower than what the PWM is normally designed to do. That's OK becuase you'll probably have lots of I/O's to customeize your own PWM scheme.

 

he said he uses a parallax microprocessor and a polulu motor driver.

I understand> the microprocessor takes the inputs (which are converted frm analog to digital) and then sends the pwm to the motor driver>?

oh so Id need his microprocessor drivers (or coding etc) is it hrd to code a microprocessor? lol

 

The microprocessor would be on the polulu board. There is even a free software development environment available for download. It looks like there is code already on the board that you only need to configure, or you have the option to write custom code.

 

The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

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erm this isnt going on a real car

if you'd read the whole thread you would have seen that...

 

Hi all thanks for your interest, sorry for being what must be annoyingly vague I forget how helpful context is lol !

For a fun project (i'm a med student and yes I procrastinate a whole lot to keep me sane ) I want to create a water injection setup for a dream track car... the 'fun' is in doing a DIY kit that is cheap and effective - I don't particularly care about the car factor I just want something challenging and interesting to do. my dad used to work repairing electronics and currently runs a computer business, guess I get the interest in electronic tinkering from him, I do have an interest in cars (and read this DIY water injection kit thing in an auto mag I'm subscribed too - they said that progressive DIY control could not be done!)

I've read tonnes of info on it all, and looked at what some of the high end kits offer.

There are 2 styles of water injection kits that use progressive volume water injection which is far superior to WI that just switches on at a certain point.... it gives progressively more water based on engine demand

style 1- uses a controller that reads MAP and MAF readings (sine voltages that relate to turbo boost levels and airflow) and subsequently changes the duty cycle of the pump to change the VOLUME of water injected into the engine. the downside of these kits is that in duty cycling the pump the pressure changes and you can get uneven atomisation - probably not that huge a problem. These kits are 400-600 $

style 2 - uses a controller that is similar to the first style, this controller however progressively on/off switches a fast switching water solenoid while a recirculating style pump maintains a constant pressure. The solenoid switches on more and off less at higher boost whatever to give the engine more water. - this style seems far superior to the first style, not to mention it's about 1000 more haha

I have read a thread from autospeed.com (water injection part 1) on people very effectively using an expresso vibrating pump (which delivers 200+psi) as the injector pump at $25 bucks its waaay cheaper than a recirculating pump

the downside is the expresso pump is AC, but the DIY people just use an inverter and hook it all up which is fine - the people however that have done this before just use the system in a way where it just comes on and sprays a constant volume, I want to try to mimic a better kit that progressively sprays more!

My thoughts
- I could use the expresso setup with a fast switching solenoid (but use what to switch it on / off progressively more rapidly or leave it on for progressively longer?)
- I could find a generic recirculating pump and then just duty cycle it with a PWM? This would be what a PWM would be suitable for right?


Well that's my thoughts for now !

I will bring this up to the rest of the moderating staff, but it looks close enough to me.