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I understand that some vehicles have mass flow sensors, as you described. Quote:
Where I'm going wrong is that severach is stating the fuel is primarily metered by temperature, citing evidence that his FE is better at warmer low altitudes (higher air density) rather than colder high altitude (lower air density). His conclusion is that fuel metering is primarily a function of temperature to account for gasoline vaporization. If the engine control system is supposed to be measuring density, then severach's observations don't make sense. Unless of course his ECU is using a less than optimal method to compute density. The only other thing that makes sense is when I looked at a standard atmosphere calculator, where I compared the air density at 1000 ft versus a 100 degree F temp at sea level. Turns out that the air density at 1000 ft is much higher than sea level at 100 deg F. If severach had temperature and altitude data, a better comparison could be made. |
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Your idea does work people need to try it before judging you on your claim.Here's a patent similar to your idea..:D https://www.freepatentsonline.com/4527533.html |
It has been known in the past that providing a means to preheat gasoline prior to entering the carburetor of a gasoline engine, can provide increased efficiency and therefore better mileage in a vehicle utilizing such an engine equipped with such a gasoline heater. For example, Canadian Pat. No. 973,439
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A lambda sensor is too slow so the only thing it regulates well is steady state. That's what the Chevette system was doing. Since rich is always acceptable the system can richen during state changes and lean out when the state steadies again. That runs fine but the emissions and efficiency are crap. All the rest of the sensors are needed to regulate when the state is changing before the slow but reliable lambda sensor can get the information out. Quote:
Here vaporization is only affecting mileage, not what the sensors see. Quote:
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severach;
My experience with FI systems fades around 1995, and was concentrated on Nissan versions. Just my opinion but it would make sense that as CPU power increases the ability to program initial trim values for fuel delivery would have become more of an ECU duty than earlier systems. The hot wire MAF sensors were prone to failure over time so it would make sense that engineers would try to find a way to eliminate them. Probably came from working with hot wire sensors that failed, and making the system still operate in failure mode, that led to the elimination of the sensor altogether with better CPU memory and programming fuel maps of better accuracy in the CPU itself. The Mass AF sensor would have a different reading depending on relative humidity, which served to cool the hot wire more than dry air and change the resistance value. Not a dedicated humidity sensor. Good reading your imput, I am learning some of the newer stuff. I have tried my WAI off and on, and it seems to have a positibe effect on mileage. However I have not tried to read temps of the air intake. I would think that temps of over 100 F would not bring on richer mixtures that quickly. Would the 02 sensor imput still cause closed loop at IAT temps over 100F or does the system go into a failure mode and open loop? The neat thing about my simple air intake snorkel reversal is the fact that as air flow increases the temp would decrease which helps when you need power, but also manitains higher intake temps under light loads. regards gary |
I noticed sitting in baaaad traffic on tuesday afternoon that "something happened" where I was bouncing off the fan all the time, going half to 3/4 scale and back again, then after a bit of that with very little movement, i.e. no engine bay airflow, the temp gauge just slowly started dropping to about 1/3... Now on these motors the plenum is known to heat soak, and on this year it has an IAT screwed into the plenum.... so I'm just wondering if it went rich to cool the motor... with sitting in that traffic an hour my last tank sucked... I couldn't get out of it, and it was moving too "fast" to turn the engine off, and too "slow" to P+G through.
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Bumping an old thread here.
Was a conclusion ever reached regarding severach's assertions? |
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