WORKING THEORY
An automotive oxygen sensor, also known as an O2 sensor, lambda probe, lambda sensor, or EGO (exhaust gas oxygen) sensor, is a small sensor inserted into the exhaust system of a petrol engine to measure the concentration of oxygen remaining in the exhaust gas to allow an electronic control unit (ECU) to control the efficiency of the combustion process in the engine. In most modern automobiles, these sensors are attached to the engine's exhaust manifold to determine whether the mixture of air and gasoline going into the engine is rich (too much fuel) or lean (too little fuel).
This information is sent to the engine management ECU computer, which adjusts the mixture to give the engine the best possible fuel economy and lowest possible exhaust emissions.
Since the air/fuel ratio in injected up-to-date vehicles is regulated by the Electronic Control Unit (ECU) and most factory ECUs are set to maintain a 14.7:1 air/fuel ratio; this is known as a stoichiometric fuel mix, user is unable to trim manually or mechanically this ratio as by early models. If too much oxygen is detected, the ECU thinks the mixture is too lean, and delivers more gas, if less oxygen is sensed, the ECU thinks the mixture is too rich and injects less gas to the engine.
5-WIRE WIDEBAND OXYGEN SENSORS
| 5-wire so called wideband oxygen sensors are more complex than standard zirconia sensors. A variation on the zirconia sensor, called the 'wideband' sensor, was introduced by Robert Bosch in 1994 but nowadays is used in only a few vehicles. It is based on a planar zirconia element, but also includes an electrochemical gas pump. An electronic circuit containing a feedback loop controls the gas pump current to keep the output of the electrochemical cell constant, so that the pump current directly indicates the oxygen content of the exhaust gas. This sensor eliminates the lean-rich cycling inherent in narrow-band sensors, allowing the control unit to adjust the fuel delivery and ignition timing of the engine much more rapidly. |  |
The wideband zirconia sensor is used in stratified fuel injection systems, and is also used in diesel engines to satisfy the serious EURO and ULEV emission limits.
 | The ECM is watching the polarity and reference voltage. A value greater than 1.00 indicates a lean air/fuel ration; conversely a value less than 1.00 indicates a rich air/fuel ratio. At idle the lambda value will typically fluctuate between .90 and 1.00. The advantage to this is the fact that the pumping current can be monitored constantly for better AFR control whereas before we had the lag time between samples. Trends in the AFR can be monitored closer than ever giving us cleaner air and better mileage. So to put in a thumbnail sketch, the wide band O2 sensor is a conventional switching sensor combined with an oxygen pump. O2 is pumped into or out of the exhaust sample chamber in order to produce it's 450mv. |
The ECM supplies a pumping voltage to the ion conductive material that separates the exhaust gas sample chamber and the exhaust stream. As the pumping voltage, and thus the pumping current, increases or decreases, as well as changes polarity, oxygen ions will be moved from the exhaust stream through the ion conductive material into the exhaust gas sample chamber.
Ions may also be moved from the exhaust gas sample chamber through the ion conductive material back into the exhaust stream. The ECM monitors the pumping voltage level and polarity required to maintain the 450 mV potential difference between the reference voltage circuit and the low reference circuit electrodes and uses this information to change the air/fuel ratio accordingly. This new commanded air/fuel ratio will burn in the engine cylinders, then pass the sensor, entering the exhaust gas sample chamber, and the adjustment process will start again. This process happens extremely quickly and thus makes the wide-range sensor much more accurate, fast, and able to detect greater deviations, rich or lean, from the stoichiometric air/fuel ratio.
If you install a hydrogen generator the oxygen content in the exhaust will rise. The more powerful HHO system you apply the more oxygen will be in the exhaust gas and this will result a fuel lean status accordingly ECU will send more fuel thus actually you will not save fuel despite this was the main reason you installed the H2O system for.
We need to trick the ECU into thinking that the engine is still burning is inefficient within the combustion chamber, by fooling the computer to sense there is less oxygen in the exhaust than there actually is. The amount of modification to the voltage signal is simply adjustable thru the enhancer unit to accommodate different amounts of hydrogen being injected.
Wideband Electronic Fuel Injection Enhancer will modify the O2 sensor signal in a 0 ... 50 % range indicating a regular pulsed fuel rich signal to the ECU. This way ECU will reduce the amounts of injected fuel and you can improve the MPG by up to 50 %.
The unit is fully adjustable. EFIE adjuster wires inline between the oxygen sensor and ECU.
EFIE O2 Sensor Adjuster is actually maximizing the Air Fuel Ratio (AFR) indicating fuel rich status. While you are injecting HHO gas into the engine you need to lean the air/fuel (gas) mixture if you really want to save gas. if you do not act so engine will work with a mixture with full of gas and HHO, reducing the power and failing MPG enhancement. When you are driving in HHO mode you have to strive to feed the engine by few gas.
The EFIE will help you to get out from closed loop - safe mode by tricking the O2 Sensor signal to the ECU, thus allowing the correct adjustments for various driving conditions to be made. Basically the oxygen sensor inform the ECU on its oxygen readings by delivering an alternating voltage between 0 ... 1 Volt.
In order to adjust this voltage the EFIE adds an adjustable value to that delivered by the oxygen sensor.
This extra voltage compensates for the variation caused by HHO. Adjustments to the trim screw can change the EFIE's voltage correction by 1millivolt. This fine tuning will allow you to reach peak MPG and result incredible economy.
Tests on fuel economy have given an increase of 8-16 MPG but may differ depending on engine, terrains, tire size etc.
INSTALLATION
Electronic Fuel Injection Enhancer adjuster wires inline between the oxygen sensor and ECU. You need to cut only the prior (before the catalytic converter) O2 sensor's signal wire and add +/- 12V to the adjuster. This device does not require a higher degree of skill it has a basic installation can be performed in 20 minutes without any special expertise. If car has one prior and one post oxygen sensor, you have to wire up a EFIE adjuster to the prior sensor only. Two EFIE units will be required for each prior oxygen sensor if dual exhaust installed with two upstream sensors before the cat.
Installation is VERY EASY and universal for each model.
1. Find the signal wire of (prior - upstream) oxygen sensor according to the chart below.
2. Cut the signal wire and contact the purple cable to the o2 sensor side, the yellow cable to the other end.
3. Contact the red wire to the ignition +12V and the black to the ground, chassis or battery negative.
COLOR MATCHING of 5 and 6-wire Wideband O2 sensors
| WIRES of O2 SENSOR | STOCK | STOCK | STOCK | STOCK | ACTION |
| signal out (Vs) | black | grey | red | black | contact here |
| sign in (Ip) | red | red | black | blue | ----- |
| sign in (Vs/Ip) | yellow | green | yellow | yellow | ----- |
| heater + | grey | light blue | grey | grey | ----- |
| heater - | white | red | white | white | ----- |
| Rcal (optional) | green | green | green | green | ----- |
Rcal = laser trimmed calibration resistor only for 6-wire wideband sensors
