US1592311A - Internal-combustion engine - Google Patents

Description

F. PQRSCHE INTERNAL CQMBUSTIOH ENGINE Filed Jan 14. 1925 Patented July 13, 1926.- p

UNITED STATES PATENT OFFICE.

FERDINAND PORSCHE, 013 STUT'IGART-UNTERTURKHEIM, GERMANY. ASSIGNOR TO DAIMLER-MOTOR-EN-GESELLSCHAFT. F WURTTEMBERG. GERMANY, A CORPO- RATION OF GERMANY.

INTERNAL-COMBUSTION ENGINE.

Applications for this invention have been filed as follows: Germany, Sept. 28, 1923; Great Britain, Sept. 29, 1924:; France, Sept.

- 27, 1924:; Italy, Sept. 27, 1924;; Austria, Sept. 27, 1924. v

This invention relates to an improved internal combustion engine operating by means of self ignition,

The reason why engines with self ignition cannot be employed is that the use of self ignition involves an explosive ignition shock of the entire charge so that considerable shocks are exerted on the pistons and the construct-ional parts connected therewith which cause what is commonly known as knocking which leads to the rapid destruction of the engine. 7

Apart from the question of knocking, assuming the knocking to be overcome, it is essential for the operation of an engine at low or high speeds to provide means to prevent the ignition shock taking place before the dead point is reached.

In itself the normal ignition, that is to say the shock producing explosion of the entire cylinder contents, is not connected with high speeds but the carrying out of this normal ignition method is impossible on account of the-said knocking. If therefore, it is desired to operate the engine with, shock ignition by increasing the compression temperature sufficiently to cause self ignition knocking must first be prevented.

One object of the invention is to provide meansto prevent knocking.

A further object of the invention is to provide a high speed engine utilizing self ignition.

The method of operation of thisinvention consists in composing in different ways as regards its self ignition temperature the mixture of fuel and air. which is to be brought to combustion by the heat of compression.

In order to form the mixture orexplosive compound two or more combustibles are em ployed, the self ignition temperature of one of which lies somewhat below the compression temperature produced by the working piston, so that the part of the. mixture or of the explosive compound formed from this fuel in the cylinder produces an explosion on ignition, ature of the proceeds more rapidly whilst the self ignition temperother fuel lies above the com- 2,452, and in Germany September 28, 1923.

pression temperature produced by the working piston so that no self'ignition of this part of the mixture can possibly take place.

By a suitable formation of the compression chamber or by suitable introduction of the two elements of the mixture or compound, provision is preferably made -to prevent any substantial mixture of these two parts of the compound.

If a. differently constituted mixture or compound as set forth above be compressed, an explosion takes place in the more easily ignitable part but the suddenly formed pressuredoes not act directly on the pistons to produce the dreaded knocking, but the suddenly formed pressure first compresses the other part of the compound and ignites it so that this part in turn is able to develop a pressure corresponding to its combustion temperature.

The ignition of one part of the compound of course proceedsextremely rapidly. But.

the development of the pressure of the sec- 0nd less inflammable part of the compound as compared with normal ignition by means of an electric spark, as the flame derived from the explosion of the more easily ignitable part of the compound has a larger active surface than the sparks of one or even more sparking plugs.

However, there is no explosion wherein the maximum explosion pressure instantaneously results but this takes place as a somewhat reton and the crank may reach the dead point in order that the highest pressure is devel oped at the dead point. 1

The crank must therefore have a high angular velocity which in motors having .a limited stroke such as are employed onautomobiles is synonymous with high speed.

It is obvious that the compound may also be formed of more than two fuels.

One example of construction illustrating the method of operation is shown in the accompanying drawing.

The diagram shows forexamplea working cylinder (1 provided with an inlet and outlet. valve, on said cylinder connects with a cylinder 1) of smaller'diameter which is also provided with an inlet and outlet valve.

In said smaller cylinder 6 is introduced that stricted development during which the pis- I compression temperature; in said larger cyl: inder a is introduced that portion of the mixture, the ignition temperature of which is higher than the compression ten'iperature.

The ignition flame is conveyed through the ignition passage and in order that no mixture of the layers of the compound contained in the two ignition chambers may take place, both layers are compressed to a uniform degree of compression. As both chambershave separate inlet valves a mixture is avoided even during charging. The provision of separate outlet valves in the two chambers has the advantage that burnt gas is constantly expelled. Any reduction of the quality of the charge by means of burnt gases is thus prevented;

I declare that what I claim is In an internal combustion engine, a Working cylinder with inlet and outlet valves and a piston, a smaller cylinder in alignment with and projecting from the end of the first-named cylinder and provided with inlet and outlet valves, a. conduit connecting the. last-named inlet valve with a source of rich gas, and a small piston carried by the main piston and loosely fitting the smaller cylinder.

In testimony whereof I atfix my signature.

FERDINAND PORSCHE.

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