HHO Hydrogen fuel cell – O2 sensor voltage adder

This is a very simple unit designed NOT to replace the O2 sensor signal but to simply add variable voltage to it, thereby causing the ECU to lean out your mix and allow the HHO to be more effective. I have been building an EFIE from plans on better-mileage.com(sp) but I started thinking about it and realized maybe we’re making this a little more complicated than it has to be. Elaborate circuits do work (I’ve been building circuits myself for many years) but there is a simpler way to accomplish the same thing AND easier for a typical person to make. Not everyone is comfortable with breaking out the soldering iron and soldering components onto a circuitboard or setting up components on a protoboard to build something elaborate. I wanted to build something that anyone could make, without having to go to that kind of trouble. What you see in this video is a unit that doesn’t take the place of the O2 sensor. Instead, it adds extra variable voltage to the already existing O2 (lambda) voltage. The voltage fluctations the ECU expects to see from the O2 sensor are still there, so you don’t get the danger of the ECU thinking something is wrong and putting itself into open-loop mode (which causes it to ignore the O2 sensor, negating any gains you were trying to make). This unit allows you to vary the amount of voltage you are adding, but you don’t need very much. Normal operating voltage from the O2 sensor runs around 0.45 volts (450 millivolts) but fluctuates about every second or so (the ECU watches for this as a diagnostic). We want to add just a little bit of extra voltage, about another 0.4 volts (400 millivolts) or so to make the ECU believe we are running rich, causing it to lean out the mix and pump less gasoline to the engine. I am using a penlight battery for my potential in this unit but once testing is completed, I’ll remove the battery and use stepped-down voltage from the vehicle’s 12-volt system to supply power for my potential (eliminating the need for a battery that will need to be replaced periodically) and provide power for a small LED digital voltage meter on the front of the box so that lambda-v voltage can be monitored. The 10k variometer allows you to adjust the trim of your potential’s voltage, within a 10k ohm window so that you have control over how much voltage you are adding to the lambda-v. You will never need the full width of this “window” because we don’t need to add much additional voltage. I may add resistors to the pot to strictly limit just how much you CAN add and may add a rectifier (diode) to the sensor wire but neither is planned unless I find they are absolutely necessary.

See updated photos of the cell and COSM/oscillator at:

http://www.freewebs.com/jhines2/apps/photos/

25 thoughts on “HHO Hydrogen fuel cell – O2 sensor voltage adder

  1. pickmylocks says:

    Hose barbs I have if you need a 10 pack, 3/8 x 3/8 Nylon.. most stores don’t carry these and home depot or lowes or they might carry a few if your lucky. never be without barbs again if your making your own cells. Ebay item 250267329649

  2. madscientist67 says:

    Hi cuja. Your best bet to see the connections is to check out the wiring diagram for this original adder on my other site. I just tried it because I wanted to just give you the link to it but their servers must be down right now. Go to this site: w w w . m a d c o s m . c o m Go to the Photo Gallery (you’ll see the link in the nav bar) and the first album you’ll see contains the diagrams for the original adder this video was about. It shows all connection points. 🙂

  3. cujafish says:

    hi Mad, im trying to copy
    and the red gromet is in the way of the wiring

    what connects to the negative of the battery ?
    do you just ground it out with the potentiometer ?

    thanx

  4. bayoujeffro says:

    Have you verified this with a change in block learn & intigrator values (long & short term fuel trim) from the ECU?

  5. BIGINSF says:

    I hooked up the eife to the same relay as the cell so they run together. My cell relay is powered via a microswitch at the throttle so the moment I touch the throttle it switches on along with a solenoid valve that opens right where the hho enters the intake. This way there is no delay waiting for hho to reach the intake. Don’t think hho does much good at idle. How about a pwm designed to increase production as accelerator is depressed? A pot controlled by throttle?

  6. BIGINSF says:

    My newest efie was made from 2 – 10Megaohm resistors and a 1 megaohm potentiometer together reducing the 12-14v from car battery. This gives me a variable adjustment from 0-2.5V that I can add to o2 sensor reading. I just experimented since I know nothing about electronics and this works good. Don’t have any issues with unregulated 12-14v voltage input.

  7. madscientist67 says:

    You could use resistors but your supply voltage could surge and sag. Instead, you want to use an LM7805. This is a voltage regulator that outputs fixed and regulated 5v DC power, then you can limit output with resistance. I went to this on this older model box before moving on to the more current COSM’s (the successor to the “adder”) to eliminate the penlight battery as well as making other features possible, such as meters and such.

  8. wh333t says:

    After watching this video a few times, I think I completely understand how to make one!

    The switch is just to turn the device on and off right?

    How could you run this off the cars existing 12v circuit? Would you get some resistors to resist enough voltage to match that of the mini battery in there?

  9. madscientist67 says:

    Take a peek at the photo gallery at: w w w . m a d c o s m . c o m (remove the space from between each character in that address). One of the first is of the original unit. Wow, it’s been a while since I even looked at that one! LOL

  10. almir334 says:

    Mad, I just finished looking at your coms IIA diagram it is proffesionaly done but it is too complicated for me, so can you please post the simple diagram of the first
    COMS that you made (the one with brown and white wires as output.) Thank you Almir

  11. almir334 says:

    nice work, can you please send me a diagram on how you connected all this and how it connects to o2. Thank you in advance Almir

  12. mymessagetomark says:

    I just unplugged my o2 sensor.I have a fuel cell on my 93 explorer and am very happy with it.I am building a much larger cell now.

  13. bass24782 says:

    incorperate a flow meter on your generator. Somehow hook it up of use it to making it produce the correct amount of voltage per volume of production. How about a inline spinning wheel thingy. When more HHO passes over it, the faster it spins and the more voltage it sends to the O2 sensor.

  14. BIGINSF says:

    Bought a potentiometer at Radio shack and can’t get it to reduce voltage at all as I turn the knob. I wonder where I went wrong? tried 25k and 10k pot.

  15. BIGINSF says:

    pretty much what I was planning on doing with a Pot. I wonder how long a 1.5V battery would last? I was thinking of using a 12V – 1.5V adapter. They are about $10 and can be adjusted for 1.5, 3, 5, 9v etc. Then add the pot to reduce down from 1.5V

  16. andy6030 says:

    gday mate
    its andy from down under…
    i have got a big arse aussie six cylinder and she sucks fuel like a hummer on roids.
    i have been mucking around with hho for a few months now and love the concept(all the usual tricks etc…
    just a thought on the permanent battery.
    you could put a ver y small solar panel to keep the battery charged.
    this must be simple as baked pie to do.

    regards andy from oz

  17. themiln says:

    Great just what I’ve been looking for!

    Another design idea is to put a rotary click switch with set amounts of volts say in increasing increments of 0.25 Volts or less, rather than a variable pot which could get very sensitive to adjust on the go.

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