Torpedo boats have their machinery stowed away in the most ingenious manner, so as to get the most power concentrated in the least number of cubic feet possible. A watch is a marvelous example of what can be done in the way of packing machinery, but it is doubtful if the torpedo boat or the watch can show such ingenuity in nesting machinery as is shown in the modern steam or gasoline automobile. When the power plant of the
There is more machinery in a gasoline automobile, yet it is nested in space very little more than is required to house the steam engine and boiler. A casual glance is enough to impress one who has any love for machinery with the fact that the mechanism is of the highest order. Every member shows the high-class workmanship which entered into its making. Every part bears witness to the skill and ingenious craft of its maker. It represents the aristocracy of engine building.
It was with a steam automobile with an engine of this kind that the world's record for steam automobiles was broken, in October, 1902, by making a mile in one minute and twenty-seven and one-fifth seconds. There was a steam pressure of 650 pounds to the square inch in the wire-wound copper boiler of the machine.
"The cylinders of the enginethere are two of themare two and a half inches in diameter, the engine has a stroke of three and a half inches and the steam is cut off at five-eighths stroke. The ordinary working steam pressure is 160 pounds. The engine weighs forty-seven pounds and is three and one-half indicated horse power. This is the engine used in the ordinary runabouts which weighs 650 pounds. The boiler is of the fire tube type. It is fourteen inches in diameter and thirteen inches long, and it has 298 copper tubes, each one-half inch in diameter. The copper shell is seamless, with steel heads, and there are about 2,000 feet of steel piano wire wound, in two layers, around the boiler to strengthen the copper shell, which is only three thirty-seconds of an inch thick. The boiler is covered with an asbestos jacket that not only prevents the steel wire from rusting but prevents loss of beat by radiation. The boiler holds about five gallons of water, but carries, when in use, but three gallons.
"The water for the boiler is contained in a tank that holds twenty-seven gallons, and it is forced from this tank to the boiler by a pump attached to the cross-head of the engine. As the pump works all the time while the machine is running, it is necessary to provide means to shut off the water from the boiler when none is needed, and this is done by means of a by-pass and an automatic valve that shunt the water back to the tank when necessary.
"The furnace of the boiler is a Bunsen burner, for gasoline is the fuel. The burner consists of 200 one-half inch copper tubes expanded between two steel plates. The tubes are for the air which is burned with the gasoline. In the steel plates are about fifty small holes for the gasoline vapor, which is taken in between the two plates through a mixing tube from the gasoline jet valve. The beat of the boiler is used to vaporize the gasoline and make it a gas. The top plate of the burner is four inches in diameter and the whole burner sits down four inches below the bottom of the boiler.
"The fire is controlled entirely by the steam pressure, which actuates a copper diaphragm whose expansion or contraction opens and closes the needle valve that feeds the gasoline into the burners; the gasoline is under an air pressure of eighty pounds to the inch, so that it jets out in spurts. The diaphragm is normally set for 180 pounds of steam. When the pressure exceeds that amount the diaphragm moves and operates the valve, which reduces the flow of gasoline and thus lowers the flame under the boiler. If the pressure falls below the working standard the diaphragm moves the other way and more gasoline is fed to the fire. The boiler is provided with a safety valve, which blows off at 260 pounds pressure. Between the boiler and the throttle valve of the engine is a globe valve which can be opened and closed only by a key carried by the operator of the automobile. If it is desired to leave the rig the key shuts this lock valve and no steam can enter the engine's cylinders.
"About five gallons of gasoline are carried in the reservoir, and as it takes one gallon to run ten to twelve miles, enough fuel for a sixty-mile run can be carried in the tank. The boiler evaporates about one gallon of water to the mile run. The speed of the machine is controlled by the throttle; the more steam the higher speed. The rear wheels are the drivers, which are driven through., differential or compensating gears. This gearing permits the outer wheel to revolve faster than the inside wheel in going around a curve. The engine drives a sprocket which transmits its motion to the differential gearing by means of a steel link belt, and the engine makes two and one-half revolutions to each turn of the gear. When running ten miles an hour the engine makes 300 revolutions. The brake is a double action band brake. Ball bearings are used on the engine as well as on the wheels, and the tires, of course, are pneumatic. The operator has at hand the steering device, throttle valve, reversing lever and brake lever, and in front of him is a steam gauge and air gauge.
"It will be noticed that the steam automobile uses gasoline for fuel and calls in compressed air as an agent to present the fuel to the flame in the best possible manner. In the automobiles operated by gasoline engines, the volatile child of petroleum is the fuel, but it is used without being first burned to raise steam. It is curious that while gasoline, is the operating agency of the gasoline motor, water, electricity and compressed air are also necessary. The water is required to keep the cylinder of the gasoline engine cool; the electricity to make the sparks that explode the gasoline at the proper time, and the compressed air to enable the operator to govern the supply of the fluid and gas.
"There is a miniature waterworks system in a gasoline automobile. If it were not for water to cool the cylinder of the engine the piston would stick, and that would end its operation, for the time being at least. The water tank lies up pretty snug to the engine and the water is forced forward through a pipe to the front of the machine, where it passes through the radiator, which might be called the dashboard. It is placed in front so as to get the full effect of the air that rushes through it and cools the water. From the radiator the water passes back and performs its office of cooling the cylinder of the engine. It then passes on and re-enters the reservoir to continue its cycle of operations.
"Now suppose the engine at rest. The forward movement of the piston sucks in the charge of air and vapor; when the piston goes back on its return stroke it compresses that charge between the piston and cylinder head, and just when the charge is at its highest point of compression an electric spark flashes through it and explodes it. The explosion drives the piston forward, and at the same time the gasoline valve is closed, so that on the fourth strokethat is, the next stroke backwardthe exhaust valve opens and the exploded gas leaves the cylinder and goes into the muffler. Then the next forward stroke sucks in a new charge and the same operations are repeated.
"This motor here is what is called an air controlled motorthe air is compressed by a pump in and about the inlet valve which feeds the gasoline to the carburetor and the gas-air mixture to the cylinder. A pipe carries the compressed air forward to the person who is running the automobile. A button controls a valve at the forward end of the pipe in such a way that it it is compressed some of the air is released and the pressure is lowered. And this operates to move the valve so as to allow not only more gasoline to pass into the carburetor, but also more of the gas-air mixture to pass from the carburetor to the cylinder.
"The electric sparks for igniting the charge in the cylinder are made by a little dynamo which is part of the outfit, but in starting the machine, however, the sparks come from an electric battery. When the machine is idlethat is, when the engine is in operation, but the automobile is standing stillthe fly-wheel of the engine makes about 100 revolutions per minute. On a good road the motor makes about 800 revolutions, going thirty miles an hour.
The horse power of this engine, which is the style used on the ordinary runabouts, is eight and a half, and the automobile as it stands weighs 1,850 pounds. In its gasoline tanks it carries about nine gallons of the fluid, which on good roads is good for a tour of from 125 to 140 miles. All parts of the engine are automatically oiled, and the mechanism as it stands there is a beautiful example of fine workmanship."
As compared with its competitors, the electric auto is simplicity itself. The driving mechanism is a first-class electric motor; the energy comes from the storage batteries that are carried on the machine. The electric automobile is clean, simple, safe and more expensive than the other styles.
Electricity from the battery passes through a controller, which, by making different combinations, of batteries, feeds more or less electricity into the motor, and consequently decreases or increases the speed of the vehicle. For instance, an ordinary electric runabout, at the lowest speed, requires about twenty volts; second speed, forty volts; and third speed, eighty volts; which means that every one of the forty cells of the batteries is at work. An ordinary electric carriage will use from seventeen to thirty amperes per hour.
The average radius of the electric vehicle is forty miles per charge, that is, the average electric auto, with one charging of its storage battery, will travel forty miles without requiring recharging. Some will go much farther-others not so far.