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/