This month we continue reprinting a series that first appeared in GEM in the March-April 1969 issue. Over the coming months, we will retrace engine history as presented by Carleton M. Mull. This segment originally appeared in the September/October 1969 GEM.
The first issues of this history of the gas engine described the events and told of the men who built the first steam engines. The successful development of these machines assisted man in the performance of labor in the early manufacturing and mining era. From the designs of the steam engine, the gas engine inventors took the mechanical pattern to experiment with a different type of prime mover. They worked with different kinds of fuel to find other sources of energy. This era extended from about 1700 to the early part of 1800.
By 1875, the general trend in design of the two types of gas engines were patented. Many mechanical modifications of the basic principles of the engines were submitted to the patent office, both here and in Europe.
Examination of engine details covered by patents in the United States during the last quarter of the 19th century is an interesting study to those who would like to see designers' ideas in the progress of the development of the gasoline engine.
The main features of the stationary engines were pretty much alike; however, the accessories such as carburation, cooling arrangements, lubrication systems, ignition and various types of pulleys and drives were still in the experimental stages.
Mixing valves for fuel intake were used on the slow speed engines and are still common on this type of engine of the present manufacturers. Such trade names as Lunkenheimer, General Valve Co., Aldrich and the Hay Co., built these valves for mixing the gasoline and air in the proper proportions.
High speed engines used carburetors which had the advantage of float type gasoline supply control. Well known manufacturers were Schebler, Kingston, Renault, Stromberg, Breeze, Aldrich and Zenith. Many engine manufacturers built their own mixing valves and some were of the type arranged to use two kinds of liquid fuel, such as gasoline and kerosene. Engines would be started on gasoline from a small auxiliary fuel reservoir. As soon as the engine was warmed up, two needle valves would allow the operator to close down the gasoline supply and open up the kerosene valve for continuous operation on the cheaper fuel.
Mention has been made of the first method used to produce ignition in the gas engines. This type was commonly obtained by some device of gas jet or bunsen burner attached to the cylinder head. The burner was kept going during the operation of the engine and timed by a valve so the flame would enter the combustion chamber.
Later development of this method of ignition used a flame to heat a porcelain or nickel alloy tube that was installed in the head of the engine, permitting the compressed fuel charge to come in contact with the hot tube creating the explosion. In some engines where the compression was high enough, the gas flame would be turned off after the engine was started and the tube would maintain sufficient heat to continue to operate the engine.
Wet cell electric batteries furnished current for the earliest electrical ignition. This type of glass jar battery was satisfactory for engines on a fixed foundation, but they were not suitable for automotive application. A good battery like the Edison, in a low tension system with an induction coil and with a make and break igniter, constituted a dependable ignition system for stationary engines.
The wet cell with the carbon electrodes and caustic soda solution was replaced by the dry cell batteries in the early 1900s. These round cylindrical dry batteries rated at 2 volts, required little maintenance and were easily adaptable to both stationary and automotive engines.
Low tension generators and magnetos rated at 6 and 8 volts were soon to be available. The Apple dynamo with a friction clutch governor operated at variable speeds with a constant voltage output. This popular little generator was manufactured by the Dayton Electric Manufacturing Co. of Dayton, Ohio.
Other horseshoe magnet type generators and magnetos were on the market at the start of the century which offered more dependable ignition systems. Some of the manufacturers were the Robert Bosch Co., the Splitdorf Electric Co., the Sumter Electrical Co., the Webster Magneto and the Wizard.
The next development of better and more dependable ignition systems was the event of the high tension spark coil and high tension magneto. With this more modern system was the introduction of the 'electric ignition plugs' or 'spark plugs'as the spark plug of today was first named. The high tension magneto with a field and wound rotor, created a flow of current which passed through the condenser built in the magneto and then to a distributor for timing to the spark plugs.
A combination of a battery and magneto system on an engine made starting easy. The engine could be started on the battery system and then switched over to the generator for continuous operation.
Many versions of the make and break igniters were in use before spark plugs. These circuit breakers were made with a set of electrical contacts in the combustion space. The early igniters of this method were built into the cylinder head. Some had one rotating electrode that made a wiping contact with the other electrode. The unit type make and break igniter was a big improvement from a service standpoint. The entire unit could be removed from the engine to be replaced by a new unit, or to have the contact points renewed.
Electric ignition plugs, or sparking plugs, as they were known when they were first used, were made in a number of types from the more or less conventional spark plug to the complicated design with a coil and timing mechanism built in the magnetic igniter. These looked like a very large spark plug and could only be installed when there was ample space around the spark plug area of the engine. The Bosch Magneto Co. built the magnetic igniter.
The Duryea automobile manufacturers built another type known as the 'Exploder.' In this plug, the timer on the engine caused the magnetic coil in the Exploder to break the circuit, allowing the full flow of current to create a strong spark across the points of the plug.