Improvements in Internal Combustion Engines.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in Internal Combustion Engines.
1, FRANCIS LEIGH MARTINEAU, of Gosford Green, Coventry, in the County
of Warwick, Engineer do hereby declare the nature of this invention to be as
follows:-
My invention has reference to motive power engines of the kind called internal
combustion engines that is, motive power engines worked by the detonation of a
mixture of combustible gas or vapour with atmospheric air..
I will describe my invention in connection with a gas engine.
Instead of effecting the detonation of the gaseous mixture in a cylinder having
a fixed bottom which fixed bottom determines the capacity of the detonating
chamber, employ a cylinder having near its bottom an auxiliary piston which
auxiliary piston constitutes virtually the bottom or closed end of the cylinder.
This auxiliary piston is capable of being moved preferably by a screwed piston rod
to a greater or less distance in the cylinder al the capacity of the detonating
chamber thereby diminished or increased. By means of a hand wheel or otherwise
the required position is given to the said auxiliary piston. The said piston is so
connected with the spring inlet valve through which the detonating mixture is
admitted into the detonating chamber or principal cylinder of the engine, that the
advance of the auxiliary piston and consequent reduction of the capacity of the
detonating chamber is accompanied by a loading of the spring valve. As a
consequence of the loading of the valve the pressure of the gaseous mixture drawn
into the cylinder is reduced proportionately to the reduction of the capacity of the
detonating space when the principal piston has reached the end of its motion into
the cylinder and the low pressure detonating mixture is compressed to the required
extent before detonation takes place. The power of the engine is reduced when
the secondary piston is advanced but the smoothness of the running of the engine
is maintained and the economy of the engine is not altered. Hence ap engine
constructed according to my invention can at pleasure be made to work at its
highest power and when low power only is required the engine can be made
to work very smoothly and economically.
The explosive gaseous mixture is detonated in the ordinary way and the exhaust
valve is opened in the usual way.
Although I prefer to connect the auxiliary piston to the inlet valve so that the
Intter shall be worked automatically they may be disconnected and each adjusted
separately by hand.
The application of my invention to oil or vapour engines differs in no essential
respect from its application to a gas engine as herein before described.
Dated this Twenty-eighth day of February 1896.
W. T. WHITEMAN,
Agent for the Applicant.

page_text: Improvements in internal Combustion Engines.
1, FRANCIS LEIGH MARTINEAU, of Gosford Green, Coventry, in the County
of Warwick, Engineer, do hereby declare the nature of my invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
My invention has reference to motive power engines of the kind called internal
combustion engines, that is, motive power engines worked by the detonation of a
mixture of combustible gas or vapour with atmospheric air and has for its object
the reduction of the compression space or detonating chamber of the cylinders of
the said engines and of the detonating charge when it is not required to work the
engines at their full power whereby great economy in the working of the engines
is effected.
I will describe my invention in connection with a gas engine.
Instead of effecting the detonation of the gaseous mixture in a cylinder having
a fixed bottom, which fixed bottom determines the capacity of the detonating
chamber, employ a cylinder having near its bottom an auxiliary piston which
auxiliary piston constitutes virtually the bottom or closed end of the cylinder.
This auxiliary pisten is capable of being moved preferably by a screwed piston rod
to a greater or less distance in the cylinder and the capacity of the detonating
chamber thereby diminished or increased. By means of a hand wheel or otherwise
the required position is given to the said auxiliary piston. The said piston is 50
connected with the spring inlet valve through which the detonating mixture is
admitted into the detonating chamber or principal cylinder of the engine, that the
advance of the auxiliary piston and consequent reduction of the capacity of the
detonating chamber is accompanied by a loading of the spring valve. As a
consequence of the loading of the valve the volume of the gaseous mixture drawn
into the cylinder is reduced proportionately to the reduction of the capacity of the
detonating space thus the pressure at the termiuntion of the inward stroke of the
principal piston is the same as if the auxiliary piston had not been advanced.
The power of the engine is reduced when the secondary piston is advanced but the
Emoothness of the running of the engine is maintained and the economy of the engine
is not altered. Hence an engine constructed according to my invention can at
pleasure he made to work at its highest power and when low power only is required
the engine can be made to work very smoothly and economically.
The explosive gascous mixture is detonated in the ordinary way and the exhaust
valve is opened in the usual way.
Figure of the accompanying drawing represents in longitudinal section the
cylinder and piston and parts connected therewith of an internal combustion
engine constructed according to my invention.
Figure 2 represents in longitudinal section and Figure 3 in cross section the
cylinder and piston of a modified arrangement of my invention hereinafter
described.
The same letters of reference indicate the same parts in the several figures of
the drawing.
I will first describe the arrangement Figure 1.
a is the cylinder of the engine and the piston of the same; c is the auxiliary
piston or movable bottom of the cylinder provided with the screw threaded piston
rod which piston rod c is moved in one or other direction, when desired, by the
rotation of the hand wheel e to which is connected the rotary screw box through
which the screwed piston rod passes. The auxiliary piston c is indicated in

page_text: dotted lines in its forward position. The outer end of the screwed auxiliary
piston rod c is connected to one end of a lever d pivotted at g to a standard or
fixed part of the franiework of the engine; the other end of the said lever d being
connected through a connecting rod to a lever i the free end of which bears on
the inner end of the spring of the inlet valve m and regulates the load on the said
spring ; is the exhaust valve of the engine worked in the ordinary way.
The action of the parts described is as follows.
When it is desired to work the engine at full, that is, at its highest power, the
parts occupy the respective positions represented in full lines in Figure 1 and the
engine works in the ordinary way.
When it is desired to work the engine at less than its highest power the han
wheel is rotated in the direction proper to advance the screwed auxiliary piston
rod and auxiliary piston e inwards into the position indicated in dotted lines, or
into an intermediate position, so as thereby to reduce the compression space or
detonating chamber of the cylinder a. The inward motion of the auxiliary piston
rod effects the simultaneous increase in the loading of the spring of the inlet
valve m so that on the charging stroke of the piston & the volume of the detonating
charge admitted by the said inlet valve m is reduced proportionately to the
decrease in the size of the compression space or detonating chamber.
Hence, the compression space or detonating chamber of the cylinder of the
engine may be adjusted to work at any desired power less than the normal or
highest power when the full power of the engine is not required and consequently
a great saving in gas results."
Although I have described and represented the auxiliary piston with a screwed
piston rod working in a rotating screw box yet I wish it to be understood that
I do not limit myself to this method of adjusting the position of the auxiliary
piston.
Although prefer to connect the auxiliary piston to the inlet valve so that the
latter shall be worked automatically they may be disconnected and each adjusted
separately by hand.
Instead of effecting the reduction of the compression space by providing the
cylinder with a movable bottom which may be advanced towards the ordinary
piston, the cylinder of the engine itself may be mounted in such a way as to be
capable of a sliding motion towards the ordinary piston, the auxiliary piston or
movable bottom of the cylinder being in this case dispensed with.
This modification of my invention is represented in Figures 2 and 3.
The cylinder a is mounted upon the slides, s and has motion communicated to it
as follows. On the underside of the cylinder a is a screw box a² in which works
the screw which screw is capable of a rotary motion only. The screw kis
rotated by the hand wheel e through the toothed wheel e2 on the hand wheel
shaft e gearing with a toothed wheel or. pinion on the screw k. The gas
admission valve and air admission valve p and mixing chamber 7 together with
the inlet valve m of the cylinder a are fixed to the said cylinder and move with it
when it is advanced in one or other direction on its slide s, s for the purpose of
decreasing or increasing the power of the engine.
The loading of the spring of the inlet valve m is effected by hand but it may be
effected automatically from the hand wheel shaft e'.
I wish it to be understood that I do not limit myself to the means described and
represented of giving motion to the cylinder as these may be varied without
departing from the nature of my invention.
The application of my invention to oil or vapour engines differs in no essential
respect from its application to a gas engine as herein before described.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that I claim
as my invention ;-
First. The improvements in internal combustion engines hereinbefore described

page_text: and represented in Figure 1 of the accompanying drawing, the said improvements
consisting essentially in combining with the cylinder of the engine an auxiliary
piston or movable bottom capable of being advanced towards the ordinary piston
or withdrawn therefrom so as to effect a reduction or increase in the compression
space or detonating chamber of the cylinder at will, whereby the said engines may
be worked at their full or highest power or at any power less than their full or
highest power, substantially as described and illustrated.
Secondly. The modified or alternative arrangement or combination of parts of
internal combustion engines herein before described and represented in Figures 2
and 3 of the accompanying drawing the said modified arrangement consisting
essentially in making the cylinder and parts connected therewith capable of a
sliding motion on the bed of the engine for the purpose of reducing or increasing
the compression space or detonating chamber of the said cylinder whereby the
engines may be worked at their full or highest power or at any power less than
their full or highest power substantially as described and illustrated.
Dated the Tenth day of November 1896.
FRANCIS LEIGH MARTINEAU.