Improvements in Gas and Oil Engines.
Year: 1895

page_text: Date of Application, 29th July, 1895-Accepted, 31st Aug., 1895
CUBE LEID DEPUITIVATION.
Improvements in Gas and Oil Engines.
I, FRIEDRICH DÜRR, Mechanical Engineer, of Lübeckerstrasse 19', Berlin, in
the German Empire, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :---
This invention relates to a gas engine or internal combustion engine, in which
the way to be taken by the combustible gas mixtures and by the products of
combustion, and the valves, are arranged in such a manner, that the engine makes
a complete cycle in two stages or in two strokes of the power piston.
The accompanying diagram is a longitudinal section of the principal parts of a
gas engine embodying my invention, and will be referred to in describing the same.
The drawing shows the power piston K in one of its extreme positions or dead
centres, after it has completed the outstroke. It also indicates by dotted lines the
other extreme position of the piston, after it has completed the instroke or return
stroke. At the beginning of the return stroke, preferably during the first quarter,
the gas valve A and the discharge valve B are opened simultaneously, the valve A
being actuated by any suitable automatic valve gear, and serving to admit the
combustible gas mixture, while the valve B communicates with any suitable suction
apparatus E operated automatically by the engine. The combustible gases drawn
into the engine enter first the chamber J and drive the waste gases or products of
combustion resulting from the previous working period, to the valve B, from which
they are rapidly drawn off by the suction apparatus E.
The bottom of the working cylinder has a cylindrical inward projection ; which
extends into the said cylinder and forms between the inlet and outlet a guide,
partition or shield adapted to prolong the way of the combustible gas mixture.
The valves A and B close again, after having remained open during about a
quarter of the stroke of the power piston.
The combustible mixture, which then remains in the cylinder and cannot escape,
is compressed during the remainder of the piston stroke, and when the latter has been
completed (the piston being in the position indicated by dotted lines), is ignited by
any suitable mechanism, so that the work of expansion begins when the piston
commences the following outstroke.
As soon as the piston again approaches its outermost position (represented by the
drawing), so that it leaves only about one quarter of the stroke to be completed,
the automatic valve gear opens the valve C, which relieves the pressure in the
cylinder, and closes again at the end of the piston stroke. When this has taken
place, the processes of charging, compressing and expanding are repeated in the
manner described above.
Instead of lifting-valves as shown, slide-valves or equivalent controlling devices
may be employed.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a gas or oil engine, a cylindrical guide or shield extending into the power
cylinder, in combination with admission, discharge and relieve valves, and a suction
apparatus communicating with the discharge valve, the said parts being so arranged,

page_text: that during a portion of the piston stroke the said suction apparatus draws off the
gaseous products of combustion enclosed in the cylinder and simultaneously draws
a fresh combustible charge into the same, that during the remainder of the piston
stroke the fresh combustible charge is compressed and ignited, that on the
completion of the stroke the compressed charge is allowed to expand against the
piston, and subsequently to escape, all substantially as described and for the purpose
specified.
2. A gas or oil engine constructed and adapted to operate substantially as
described and represented by the drawings.
Dated this 26th day of July 1895.
FAIRFAX & WETTER,
433, Strand, London, Agents.