Improvements in Gas and Oil Engines.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Gas and Oil Engines.
I, GEORGE CROYDON MARKS, of 18, Southampton Buildings, London, W.C.,
Consulting Engineer (being a communication from abroad by Eugene Spitz, of
42, Boulevard Bonne-Nouvelle, 42, Paris, in the French Republic) do hereby
declare the nature of this invention to be as follows;
-
This invention relates to gas and oil motors and its object is to provide a new
arrangement in the cycle of operations of such engines.
The invention consists generally in interposing between any known cycle of
operations in gas or oil engines certain inactive periods or fractions of periods
and these at regular and periodical intervals.
This interposition of inactive periods has for its object the prevention of
excessive heating of the motor cylinder by diminishing the number of explosions
in a given time and thus permit the utilization of an engine in such places where
it is inconvenient to employ the ordinary methods of cooling the cylinder walls.
In carrying the invention into effect as applied to the cycle of operations
almost universally used in gas and oil engines and known as the "Otto" where
an explosion takes place every second revolution of the engine the arrangement is
as follows:
"
"
The
Consider first that the suction valve is automatic and also that the eduction or
exhaust valve is controlled by a single cam, then, in ordinary circumstances, the
successive operations of the Otto cycle consist of suction, compression, explo-
sion, exhaust, suction, compression, explosion, exhaust, and SO on.
work of the motor could thus be represented in active or four-phase
periods of suction, compression, explosion, exhaust, and it is the object
of the present arrangement to insert between each of these four-phase or active
periods an inactive period of equal duration and represented equally by two
revolutions of the engine. In this inactive period, therefore, none of the phases
would be produced but the piston. would only suck in and blow out pure air or
air mixed with spent or burnt gases by the exhaust valve which would remain
open during the whole time of the said inactive period, or, again, by a special
valve making communication between the cylinder and atmosphere.
In
It is evident that with an arrangement of this kind an explosion would only
take place every four revolutions of the engine being half the number at pre-
sent. The cooling cylinder being uniform or nearly so the heating with this
arrangement would be much less not only owing to the fewer explosions but
because of the flushing with cold air produced during the inactive period.
the ordinary construction of engine the exhaust cam is carried upon a side shaft
driven at half the speed of the engine motor shaft and as the time during which
the exhaust valve is to be kept open is approximately equal to half a revolution
of the engine it is evident that the extent of rise upon the cam would be equal
to a quarter revolution of the side shaft, that is to say, have a development
of 900. When, however, an inactive period or phase is introduced between each
active four-phase period a different construction is necessary. The side shaft is

page_text: geared to run at one-fourth the speed of the motor shaft and it is then evident
that to use the exhaust valve to produce the inactive periods by remaining open
the development of the cam must be as follows:-The two revolutions covering
the inactive period of the motor shaft are plus the half revolution required for
the quarter-phase representing the exhaust in the active period, that is to say,
360° x 2.5=900° corresponding to 2250 development of the cam upon the
side shaft.
900°
4
=
=
=
In the case where a special valve (other than the exhaust) would be employed
to put the cylinder in communication with atmosphere during the inactive period
it is then evident that with a shaft running at one-fourth the speed two cams
could be employed, one cam being used for the exhaust phase of the active period
1800
and having a development thereof of = 45°, and the other cam arranged
4
parallel with the first cam and in such a position relative thereto that its rise
would start immediately after the finish of the exhaust stroke on the other cam,
and this second cam having a development of 225°-45° = 180°. The second cam
would therefore cause a valve to communicate with atmosphere during the idle
two revolutions of the engine.
For simplicity of explanation in the hereinbefore described modification the
mechanism controlling the inactive period only has been described and it is
evident that in practice as many inactive periods or fractions of periods could be
introduced as required by modifying the relations of the speeds of the motor
shaft and the side shaft controlling the ordinary cycle of operations, or, further,
by modifying the distribution and development of the cams controlling the
exhaust, or by any other equivalent arrangement which would introduce the
regular inactiva periods between the ordinary cycles of operations. It is also
evident that the arrangement can be equally well applied to other cycles than
that of "Otto," such as, for instance, a cycle using an explosion every revolu-
tion, and that any number of cylinders, periods of cycles, construction of valves,
or differing gas or oil mixtures, may have this arrangement applied to them, and
all without departing from the subject of the present invention.
Dated this 27th day of
1000
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and.
13, Temple Street, Birmingham, Agents.
Improvements in Gas and Oil Engines.
I, GEORGE CROYDON MARKS, of 18, Southampton Buildings, London, W.C.,
Consulting Engineer (being a communication from abroad by Eugene Spitz, of
42, Boulevard Bonne-Nouvelle, Paris, in the French Republic) 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 gas and oil motors and its object is to provide a new
arrangement in the cycle of operations of such engines.
The invention consists generally in interposing between any known cycle of
operations in gas or oil engines certain inactive periods or fractions of periods
and these at regular and periodical intervals.
This interposition of inactive periods has for its object the prevention of
excessive heating of the motor cylinder by diminishing the number of, explosions
in a given time and thus permit the utilization of an engine in such places where
it is inconvenient to employ the ordinary methods of cooling the cylinder walls.

page_text: means to carry the invention into enecare mustrated in The accompanying
sheet of drawings as follows:-
:-
Figure 1 is a comparative diagram of an engine on the "Otto" cycle illus-
trating the improved cycle of operations.
"
Figure 2, is a diagrammatic view of the gearing operating the exhaust cam in
an ordinary "Otto" engine.
Figure 3 is a diagrammatic view of gearing designed to operate the exhaust
cam when the improvements are applied.
Figure 4 is a perspective view of a further modification in the improved
gearing.
In carrying the invention into effect as applied to the cycle of operations
almost universally used in gas and oil engines and known as the "Otto" where
an explosion takes place every second revolution of the engine the arrangement is
as follows:-
Consider first that the suction valve is automatic and also that the eduction or
exhaust valve is controlled by a single cam then, referring to the atmospheric
line A Figure 1 in ordinary circumstances, the successive operations of the
"Otto" cycle consist of suction a, compression b, explosion c, exhaust d,
suction a, compression b, explosion e, exhaust d, and so on as respectively shown
by these spaces and in the diagram by thick lines. The work of the motor could
thus be represented in active or four-phase periods of suction, compression,
explosion, exhaust, as on line A Figure 1, and it is the object of the present
arrangement to insert between each of these four-phase or active periods an
inactive period of equal duration and represented equally by two revolutions of
the engine, and as clearly shown at line B Figure 1 between the spaces lettered D.
In each inactive period D, therefore, none of the phases would be produced but
the piston would only suck in and blow out pure air or air mixed with spent or
burnt gases by the exhaust valve which would remain open during the whole time
of the said inactive period, or again by a special valve making communication
between the cylinder and atmosphere, all as hereinafter more particularly
described.
It is evident that with an arrangement of the kind indicated on line Ban
explosion would only take place every four revolutions of the engine, being half
the number at present. The cooling of the cylinder being uniform or nearly so
the heating with this arrangement would be much less not only owing to the
fewer explosions but because of the flushing with cold air produced during each
inactive period 1. In the ordinary construction of engine and as shown at
Figure 2, the exhaust cam e is carried upon a side shaft f driven at half the
speed of the engine motor shaft y, and as the time during which the exhaust
valve is to be kept open is approximately equal to half a revolution of the
engine it is evident that the extent of rise upon the cam e would be equal to a
quarter revolution of the side shaft, that is to say, have a development of
90 degrees as marked upon the drawing. When, however, an inactive period or
phase is introduced between each active four-phase period a different construction
is necessary, and one modification to effect this alteration is illustrated at
Figure 3. The side shaft is geared to run at one-fourth the speed of the motor
shaft and it is then evident that to use the exhaust valve k to produce the
inactive periods by remaining open the developement of the cammust be as
follows: The two revolutions covering the inactive period of the motor shaft
are plus the half revolution required for the quarter-phase representing the
exhaust in the active period, that is to say, 360° × 2.5=900° corresponding to
900° =225° developement of the cam upon the side shaft as shown upon Figure 3
4
of the drawings.
:
Figure 4 illustrates the cam gearing in the case where a special valve (other than
the exhaust) is employed to put the cylinder in communication with atmosphere
during the inactive period. It is evident that with a shaft m running at one-
fourth the speed two cams such as n and o could be employed, one cam n being

page_text: 180°
4
=
used for the exhaust phase of the active period, and having a developement
thereof of
45° as marked upon the drawing, and the other cam o arranged
parallel with the first cam n and in such a position relative thereto that its rise
would start immediately after the finish of the exhaust stroke on the other cam,
and this second cam having a developement of 225°-45° = 180° as also marked
upon the drawing. The second cam o would therefore cause a valve to communi-
cate with atmosphere during the idle two revolutions of the engine.
.
For simplicity of explanation in the herein before described modification the
mechanism controlling the inactive period only has been described and it is
evident that in practise as many inactive periods or fractions of periods could be
introduced as required by modifying the relations of the speeds of the motor
shaft and the side shaft controlling the ordinary cycle of operations, or, further,
by modifying the distribution and developement of the cams controlling the
exhaust, or by any other equivalent arrangement which would introduce the
regular inactive periods between the ordinary cycles of operations. It is also
evident that the arrangement can be equally well applied to other cycles than
that of "Otto," such as, for instance, a cycle using an explosion every revolu-
tion, and that any number of cylinders, periods of cycles, construction of valves,
or differing gas or oil mixtures, may have this arrangement applied to them, and
all without departing from the subject of the present invention.
Having now particularly described and ascertained the nature of my said
invention, and what manner the same is to be performed, I declare that what
I claim is:-
1.) In a gas or oil engine arranging its active periods or cycles separated from
each other by inactive periods or fractions of periods and causing the cylinder to
communicate with atmosphere during the said inactive periods either by the
exhaust or a special valve and all as a means of cooling the said cylinder.
Dated this 0641 dav
Tuna 1000
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents.