Putnam's Automobile Handbook: The Care and Management of the Modern Motor-Car

by H. Clifford Brokaw; Charles A. Starr

This condition of gas was absent for several years. In the early days of automobile construction, before the manufacturers were able to devise a carburetor for vaporizing gasoline under all conditions, we had this same trouble as soon as the weather turned cold. Persistent experiments produced a carburetor which overcame the trouble. Then almost as soon as a carburetor was developed which would vaporize the gasoline under adverse conditions, somehow the volatility of the gasoline was found to have decreased.

You will remember the contest between armor plate and big guns—as soon as an impenetrable armor plate was invented, some genius would go ahead and find a powder or gun which would shatter the impenetrable plate. Then the armor factory would try to find something to outwit the gun maker. That is the way with carburetor and gasoline. It is time for the carburetor maker to devise a scheme to volatilize the heavy gasoline now supplied under all conditions—particularly in cold weather. There are signs that he is matching up to the emergency.

It is true that the gasoline now sold has a greater heat-producing quality, if only we can get it properly mixed and volatilized. It may be that the gasoline producers, by putting heavier gasoline on the market, have been of a real service to auto men, once we have learned to utilize it economically and efficiently. They may have had in mind the higher power, but they have given us a gas which is very hard to vaporize on a frosty morning. Sometime soon, probably the carburetor man will catch up and give us a vaporizer which will handle it. Until they do, we will have to look for means of overcoming the difficulties now experienced, and it is largely a question of warming up the air.

In changing gasoline from liquid to vapor, considerable heat must be supplied. When the atmospheric temperature is too low, there is not sufficient heat in it to vaporize the gasoline sprayed into the carburetor. When the engine is warm, the process of vaporization goes on from the needle valve to the moment of ignition, but if the engine is cold, the process is retarded more or less, and under some conditions it is possible for thoroughly vaporized gasoline to be again condensed. The man who does not understand is inclined to say uncomplimentary things about the engine and talk about “fireproof gasoline.” The only trouble is that the temperature is so low that we must heat the air before we send it into the carburetor. Practically all the carburetor manufacturers put out a “stove” to heat the air supply, which is attached around the exhaust pipe, so that the hot air surrounding the pipe is conveyed to the carburetor, which warms the air entering the intake, thus supplying the heat necessary to effect vaporization. This “stove” or gas warmer, the chauffeurs are beginning to call a “hot-air furnace.”

The process of vaporization absorbs a large amount of heat. To raise the temperature of the liquid one degree takes a certain amount of heat. The amount required per degree remains the same until the point of vaporization is reached, when two hundred times that amount of heat is required to effect vaporization. The “hot-air furnace” supplies the extra amount of heat.

A great many carburetors have the mixing chamber water-jacketed and the water from the cooling system is circulated through it, supplying some heat in that way. Sometimes that in itself is sufficient, but at present it seems advisable to use both. Neither one of these is in operation when the engine is started; the “hot-air furnace” depends upon the exhaust pipe being heated, and the water-jacket upon the engine itself being heated long enough to warm up the circulating water. So that it becomes necessary to find some means to supply heat until these warm up.

When the car is started in a warm garage the gasoline will vaporize properly and the engine will run in good shape, but as soon as the car goes out into the cold air it will cool the engine so that some of the gasoline will be condensed. Therefore we close the radiator cover partly or wholly until the engine is thoroughly warmed. If the car is started in a cold garage, the teakettle and dishrag method must be resorted to. Wrap the cloth around the carburetor so that it does not cover the air intake, and pour the boiling water on the rag, taking care that none gets in the air intake. The hot water will heat the carburetor and intake pipe and raise the temperature of the mixture so that the engine will run. In some cases it may be necessary even to drain out the cooling system and fill it with hot water, so that the combustion chamber becomes heated up.

As the weather becomes colder it will be found necessary, no doubt, to close up the radiator more and more in order to keep the engine at the required temperature. High engine temperature, up to the point where the water in the cooling system begins to boil, is desirable from the standpoint of efficiency, and if no trouble is experienced with irregular running, the hotter the engine is, the larger amount of power is developed.

One manufacturer has incorporated in the radiator a shutter-like device, by means of which the amount of air admitted may be regulated from the driver’s seat. Doubtless others will follow, or find an equally good substitute.

Radiator covers to fit almost any car now made may be procured at trifling expense; one may simply put a piece of cardboard over it. Being out without a cover recently when the engine did not work right, the author stopped when he came to a newsboy and bought a paper and tied it over the radiator, getting home all right with this substitute.