This is purely speculation, but I believe there is merit in my analysis. It stems from the figures obtained wrt Lambda readings. I do not want to have to spend a lot of money, re- calibrating my AFR by way of expensive software modifications.
So I have been investigating wide - band Lambda Probes. Those fitted to the manifolds are Bosch LSU 4.2's and there is, as usual with Bosch, data sheets available to which engineers can refer.
The principle being that Stoichiometric represents an AFR of 14.7:1 air/fuel ratio. Now, according to my research, in terms of sensor voltage this equates to 350 milli - volts. Ultimately this is derived from the sensor current which is "Tuned" to 1 milli - amp. This voltage is determined as being central to the linear section of the sensor at Stoic. Any variation from this is a function of the "Cell Impedance", which varies depending upon the fuel/oxygen Ions across the "pump".
The Bosch Lambdas have an external calibration resistor, to compensate for manufacturing tolerances, the value of which is chosen to normalize the Pump Current to 1 milli - amp.
So I thought, if I was to increase or decrease the value of the calibration resistor, the closed loop system would cause the ECU to re - adjust the current in the loop to 1mA. So I could; at will, modify the AFR, and importantly, it would be applicable at all points across the rpm range.
Tonight, I had a quick pint with a friend of decades standing. He also happens to be a very senior marine engineer. He quickly picked up on what I was saying and simply stated, "So, you have been talking to VAG then! Switch resistance when your car is due an MOT or subject to compliance tests, then switch it out again, when in normal use?"
I was flabbergasted at the speed at which he grasped what it is that VAG appear to do. So simple, so inexpensive, yet so effective.
If anyone can suggest there is anything more to what VAG have done, I would appreciate the input. However, the next stage is to test the theory.
So I have been investigating wide - band Lambda Probes. Those fitted to the manifolds are Bosch LSU 4.2's and there is, as usual with Bosch, data sheets available to which engineers can refer.
The principle being that Stoichiometric represents an AFR of 14.7:1 air/fuel ratio. Now, according to my research, in terms of sensor voltage this equates to 350 milli - volts. Ultimately this is derived from the sensor current which is "Tuned" to 1 milli - amp. This voltage is determined as being central to the linear section of the sensor at Stoic. Any variation from this is a function of the "Cell Impedance", which varies depending upon the fuel/oxygen Ions across the "pump".
The Bosch Lambdas have an external calibration resistor, to compensate for manufacturing tolerances, the value of which is chosen to normalize the Pump Current to 1 milli - amp.
So I thought, if I was to increase or decrease the value of the calibration resistor, the closed loop system would cause the ECU to re - adjust the current in the loop to 1mA. So I could; at will, modify the AFR, and importantly, it would be applicable at all points across the rpm range.
Tonight, I had a quick pint with a friend of decades standing. He also happens to be a very senior marine engineer. He quickly picked up on what I was saying and simply stated, "So, you have been talking to VAG then! Switch resistance when your car is due an MOT or subject to compliance tests, then switch it out again, when in normal use?"
I was flabbergasted at the speed at which he grasped what it is that VAG appear to do. So simple, so inexpensive, yet so effective.
If anyone can suggest there is anything more to what VAG have done, I would appreciate the input. However, the next stage is to test the theory.