Good hip shop and right on the trail.

Let me tell you a bit about adaptation versus control. Closed loop control started in engines with lambda systems in 1980. The last year of 450s got such control. Very simple idea. Make a mechanical system to get close to a precise amount of fuel and then use an after the fact sensor (the O2 sensor) to evaluate how good the job was done. Then use electronics to correct, then sense the result and correct, and then sense the result and correct. The concept used with a system that could react in about 250 milli seconds was able to achieve an exact mixture by moving rich, lean, rich, lean, etc turning as soon as the midpoint is passed. the quicker the readings the narrower the swing rich, lean, rich. Placed in terms of percent CO (Carbon Monoxide the mixture gas in 5gas testing), the ideal is .5% CO. The O2 sensor reads from 0.0% to 1.0% CO correct running closed loop will have voltage swings from .2 to .8v on the O2 sensor. The faster the reaction the smaller the swing. From zero to one the percent O2 sensor voltage can be directly extrapolated to CO% .5v = .5% CO.

On these systems the base mixture had to be set as the systems ability to correct was limited. Proper mixture was to be set to .5% CO using an analyzer without the O2 sensor connected.

All of this sounds a lot like adaptation because mixtures are being adapted to a value. But it is really just feedback control. Adaptation started with the electronic systems which were no longer adjustable. The non adjustment was required to keep cars in closed loop without constant maintenance AND to prevent people from being able to over ride the system with mechanical adjustments.

So now adaptation is where the car changes its center of correction as the requirements change. If for example the car decides that 10% more fuel on average is needed to maintain mixture in the center of the correction capability it now moves that center ten percent. Current adaptations give the modern controller slightly less ability to go rich than to go lean but the original fuel calculation from algorithm can be moved from .68 of one to 1.25 of one, with one being the original calculation.

During warm closed loop considerations it really doesn't matter so much about adaptation. Where it matters is cold or during all fast activities. Because the car decides that due to wear and infirmity of components the current fuel needs are to be increased by 20% ( say due to restricted injectors) . The system now is running at 1.2 adapted. Now when you go start the car up cold its fuel calculation which was richer (for cold running calculation) anyway is now preset 20 percent richer. This is before the O2 sensor is warm enough to help out. The old car would have corrected rich when hot but when cold it would have went to its middle of the road setting made hot. If there were restricted injectors the car would suffer during cold running and also everywhere there was things hapeening faster than 250milliseconds. (snap acceleration comes to mind)

So I have about got myself confussed, I better stop.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician