At the risk of being ridiculous, pehaps this is one of the questions being asked:
A self-cleaning (pyrolytic) oven cleans by INCINERATING the grease and dirt an-aerobically at approximatly 900*F or higher. In other words in an oxygen-deficit situation.This is similar to the cells in your body that "burn" food, (in limited oxygen)yet it is done without open flames.
Therefore the door on such ovens locks for safely and to keep oxygen from rushing in. I believe the lock-temp is above 600*F as a normal oven hi-temp is 550*F.
IIRC, Electric self-cleaners came out around the early 60's, invented by GE.
Gas self-cleaners were problematic in that the oven burners require primary(mixed-with-the-gas) combustion air and secondary combustion air (freely available air/oxygen) to support the flames. Traditional older gas-stove designs with a broiler drawer under the oven cavity had one gas-burning tube to perform both broil and bake functions by heatign both cavities simultaneously. This proved to be unworkable for the intents of a self-cleaning (pyroytic)gas stove. Besides, how would you self-clean two oven cavities?
I believe it was Caloric that pioneered the first gas self-cleaner. This was accomplished by having only one oven cavity with two burners, top to broil and bottom to bake/roast similar to what is found in an electric oven.
Providing adequate primary coinbustion air was solved by moving the Venturi OUTSIDE of the oven cavity. (The Venturi is a mechanical device that is just past the gas-orifice valve with an air-shutter; it mixes air with the gas. Rushing gas creates a suction that draws in air.) Adequate secondary combustion air is accomplished by having VERY limited air accessible to the burner flames. This is normally now seen in gas self-cleaners in the form of slats or small holes near/under the bake/roast. Of course one no longer sees totally unrestriced air to the burner.
Similalty, a gas stove must have a vent to exhaust posionous byproducts of combustion from the oven cavity to make way for the necessary fresh/clean oxygen for combustion. This is what makes a gas oven HELLISHLY hot; a great deal of heat leaves the oven via this vent. {In an electric oven a one-inch round "token" vent exists basically to keep air pressure inside and outside of the oven equal and to prevent an out-rush of gasses into the users face upon opening the oven door. It may also be to allow smells out to detect if something in the oven has caught fire.
Some people say gas ovens make food more tasty. I say that gas ovens let smells escape to a greater degree enticing the appetite. The sense of taste and smell are highly linked in humans. Witness where the nostrils are. Think also about how food has "no taste" when one has a cold (i.e. stuffed-up nose).
It should be noted that on a gas oven the BTU/H heat input was apporimately 12,000 BTU/h before the advent of the self cleaning oven. Therefore at higher temps it was "on" nearly constantly to maintain the set temp. Due to the need for a higher oven cavity tetmeperature to pyrolytically clean at nearly 1,000*F the newer ovens have oven burners of about 18,000 BTU/h or roughly a 50% increase. These therefore are "OFF" more frequently especially at lower set temps. Bottom line is that a self-cleaner in gas browns and heats entirely differently than a manual-clean oven. I would guess a similar situation happened with electrics as they went from manual-clean to self-clean.
Anyhoo, too much said. Ciao for now.
