Patent No. 28022 from 16th of December, 1883
Gas engine - G. Daimler from Canstadt
The innovations in gas engines and oil engines consist of a piston pressing air mixed with ignitable materials (gases, steams, oil etc.) against the hot walls of a closed and heat-protected or not cooled space at the end of a cylinder so that at the end of the stroke, by means of the effect of the compression a self-ignition or, so to speak, pneumatic ignition and fast combustion of the whole amount of the mixture occurs, the power of which can be used as a driving force. Fig. 1 of the drawing, A is a cylinder in which the piston B moves. One end of the cylinder is closed by cap C, which is wrapped in poor heat conductors (clay, slag wool) and as far as possible heat-isolated from the cylinder. The piston bottom is also wrapped in poor heat conductors. When piston B is raised air will be mixed with gas or oil and sucked or pressed in through valve D. The piston compresses the mixture in the space C and it is ignited at the end of the stroke. Combustion and expansion of the mixture drives back the piston with significant power which can be transferred by crank or other mechanics. The next upward movement of the piston removes the combustion remains completely or partially through the exhaust valve G; then the whole process starts again etc. etc. After several repetitions of this process the walls of space C and the piston bottom are warmed up to a normal raised temperature, which ignites the mixture regularly in and around the upper piston position as a result of the compression, according to the empirical statement that combustible mixtures, which would not burn under atmospheric pressure or only slowly, burn fast or even explode under compression. To make the mixture explode at the beginning of the process when the walls of the combustion chamber are still cold, the metal ignition cap F, which has a constantly opened connection to the combustion chamber, is heated up by an external flame so that ignition starts only at the end of the compressing move, as long as self ignition starts.
1) The procedure for gas or oil engines to rapidly compress an amount of combustible mixture (air mixed with oil or gas etc.) in a closed room so that it self- ignites at the moment of the highest compression, thus exploding or rapidly burning the mixture and then to use the power created by the combustion as a driving force. 2) The ignition cap, which is constantly open to the combustible mixture and which will be heated up so that the ignition occurs only at the end of the compression stroke.