In a message dated 11/10/02 9:14:02 PM Eastern Standard Time, paulholm@xxxxxxxxxxxxx writes:It might be interesting to hear more from Joe about the development Paul, (And all) When I was at Chrysler, we used "Positive displacement" carburetor flow stands. We ran flow curves on carburetors from idle through wide open throttle using large vacuum pumps to simulate an engine. We started at idle (Closed throttle) with the manifold vacuum set at 18.5"hg, with the flowstands set at maximum airflow, and recorded periodic readings of the fuel/air ratio as we opened the throttle.When we reached WOT we reduced the airflow to simulate going up a large hill with the pedal to the metal until the airflow reached zero. That gave a curve which could be used to compare one carburetor to the next, and we could change the curve as needed. We recorded idle, off-idle, road load, step-up cut in, and finally the WOT curve. The positive displacement flow stands used laboratory gasoline that had a known density and we timed the flow of a known quantity of fuel and a known quantity of air to establish a ratio of fuel to air. The air was drawn from large drums of known volume that were pulled down into a water seal. These drums lifted measuring sticks hung from pulleys at the operators station. The carburetor was mounted under a large hood that we pulled down into a moat for an absolute seal that never wore out. Airflow was measured in "Pounds Per Hour" because it was a more exact measurement and could be controlled. As you started a reading you drew fuel from a burette and started a stopclock at the start mark and stopped it when the fuel ran out. Simultaneously, you lowered the hood over the carb and timed the known quantity of air. After a year or so of this, you knew absolutely everything about carburetors, and were able to bore a large audience to tears, as I just have you all! ENJOY! Joe Savard Lake Orion, MI |
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