Improvements in Gas Engines.
Year: 1890

page_text: Date of Application, 16th Sept., 1890
Complete Specification Left, 16th June, 1891-Accepted, 1st Aug., 1891
PROVISIONAL SPECIFICATION.
Improvements in Gas Engines.
I JAMES ROOTS Engineer Mottingham Kent do hereby declare the nature of this
invention to be as follows:-
During the suction stroke for about half the stroke gas and air are drawn together
into the cylinder forming the explosive charge then for the remainder of the suction
stroke air only is drawn into the cylinder either by a different or the same valve.
During about half the in or what is usually the compression stroke the air is
displaced or ejected from the cylinder either into a separate chamber or into the
mixing chamber from whence it may at the next suction stroke be again drawn into
the cylinder with gas and form the next charge. The charge left in the cylinder
after the displacement is then compressed in the remaining half stroke and fired
Or the reverse
having a double expansion and then exhausted in the usual manner.
of this action, air being drawn into the cylinder during the first half of the stroke
and explosive charge in the second half then the air is first displaced in the instroke
leaving the charge behind the piston to be compressed as before described. The
valve by which the air is ejected may be in the middle of the stroke.
A modification of this arrangement for effecting double expansion may be com-
bined with the division of the charge into two portions described in my Specification
9310 of 1888, as follows
The second explosion chamber is preferably placed at the side of the cylinder in
horizontal engines with the mixing chamber bolted at the end of it. The admission
valve spindle passes through the neck to the outside of the mixing chamber instead
of through its centre. A lever by means of a cam on the exhaust valve shaft opens
the valve at the proper time and retains it open during nearly half the instroke
while about half the cylinder contents are ejected from the cylinder to the second
explosion chamber and on to the mixing chamber. When combustion occurs the
charge is expanded to nearly double the volume of the original contents but to more
than double the volume of gas and air fired: as during the in or exhaust stroke, the
exhaust valve is preferably closed before the stroke end by about one sixth. Thus
the portion ejected is drawn through and returns through the second explosion
chamber and the combination is effected in a very simple manner and with a very
economical result. The exhaust valve is opened by cam and lever in the usual
manner and is preferably fitted in the cover.
The gas valve is controlled by a lever which has attached to it a spiral spring the
other end of which is attached to a fixed stud so that when in the central or straight
line position the lever by the spring tension will move in either direction at the
slightest touch of the adjustable pins on the rod fixed to and raised by the centri-
fugal ball governor. The spring may also be fitted to a toothed quadrant acting in
the same way the teeth of which gear into a pinion fixed to the screw spindle of the
gas valve. If the governor be fitted to the rotating exhaust valve shaft a groove is
substituted for the adjustable pins before mentioned and an intermediate lever with
adjusting screws may be used."
For ignition a small chamber may be placed partway in the tube or channel used
for ignition as near as possible to that part of the tube kept red hot by atmospheric
burner: the chamber is lined with asbestos fibre, slag wool or other incombustible
material to ignite the charge. A small gas supply with a valve to prevent leakage
of the charge into the gas pipe may be fitted to the chamber. The gas-tubing
ignition pipe may be lined with a silicate to prolong its life. The inner part may
be a carbon tube in the clearance space or in a recess in the cover.
The cover and

page_text: clearance space may be lined with carbon and the tube may be formed by a hole or
channel bored in the carbon disc lining the cover.
September 19th 1800
:
COMPLETE SPECIFICATION..
Improvements in Gas Engines.
I, JAMES ROOTS, Engineer, of 166 Fleet Street, City of London formerly of
Mottingham, Kent, 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 :-
During the suction stroke for about half the stroke, gas and air are drawn
together into the cylinder forming the explosive charge then for the remainder of
the suction stroke air only is drawn into the cylinder either by a different, or the
same valve. During about half the in or what is usually the compression stroke,
the air is displaced or ejected from the cylinder either into a separate chamber or
into the mixing chamber from whence it may at the next suction stroke be again
drawn into the cylinder with gas and form the next charge. The charge left in the
cylinder after the displacement is then compressed in the remaining half stroke and
fired having a double expansion and then exhausted in the usual manner. Or the
reverse of this action, air being drawn into the cylinder during the first half of the
stroke and explosive charge in the second half then the air is first displaced in the
instroke leaving the charge behind the piston to be compressed as before described.
: The valve by which the air is ejected may be in the middle of the stroke.
A modification of this arrangement for effecting double expansion may be com-
bined with the division of the charge into two portions described in my Specification
9310 of 1888 as follows. The second explosion chamber is preferably placed at the
side of the cylinder in horizontal engines with the mixing chamber bolted at the
end of it. The admission valve spindle passes through the neck to the outside of
the mixing chamber instead of through its centre. A lever by means of a cam on
the exhaust valve shaft opens the valve at the proper time and retains it open
during nearly half the instroke while about half the cylinder contents are ejected
from the cylinder to the second explosion chamber and on to the mixing chamber.
When combustion occurs the charge is expanded to nearly double the volume of
the original contents but to more than double the volume of gas and air fired, as
during the in or exhaust stroke, the exhaust valve is preferably closed before the
stroke end by about one sixth. Thus the portion ejected is drawn through and
returns through the second explosion chamber and the combination is effected in a
very simple manner and with a very economical result. The exhaust valve is
opened by cam and lever in the usual manner and is preferably fitted in the cover.
The
gas valve is controlled by a lever which has attached to it a spiral spring, the
other end of which is attached to a fixed stud, so that when in the central or straight
_line position, the lever by the spring tension will move in either direction at the
slightest touch of the adjustable pins on the rod fixed to and raised by the
centrifugal ball governor.
The spring may also be fitted to a toothed quadrant acting in the same way,
the teeth of which gear into a pinion fixed to the screw spindle of the gas valve.
For ignition, a small chamber may be placed part way in or attached to the
external tube or channel used for ignition and which is kept red hot by atmospheric
burner; the chamber is lined with asbestos fibre, slag wool, or other incombustible
material to ignite the charge. The gas-tubing ignition pipe is heated and dipped
into a solution of silicate of soda to prolong its life. The inner part may consist of
a carbon tube in the clearance space or in a recess in the cover. The cover and
clearance space may be lined with carbon and the tube may be formed by a hole or
channel bored in the carbon disc lining the cover.

page_text: In order that my invention may be clearly understood I have appended the
accompanying sheet of drawings in which Figure 1 is a part sectional elevation of
all that is necessary to illustrate the first part of my invention A being the cylinder
into which a combustible charge of gas and air are drawn by the outmovement of
the piston for about half its stroke the gas valve B being kept open by means of a
cam C of the required peripheral length fixed upon the shaft D. During the
remainder of the stroke the cam C allows the gas valve B to close cutting off the
supply so that air only is drawn into the cylinder which upon the return stroke of
the piston is displaced either into the mixing chamber or through the exhaust valve
which is opened for this purpose. The combustible charge left in the cylinder after
the air displacement is then compressed and fired but is expanded to twice its former
volume giving therefore double expansion after which it is exhausted in the usual
manner.
Figures 2. 3 and 4 represent sectional plan, part sectional side elevation and part
sectional end elevation respectively of an engine, constructed according to the
second part of my invention being a modification of the before described arrange-
ment, whereby double expansion combined with the division of the charge in two
portions is effected as described in my former Specification No. 9310 of 1888.
Referring more particularly to Figure 2 the second explosion chamber E is placed
preferably at the side of the cylinder A with the mixing chamber F attached to it
as shown in Figure 3 with the admission valve spindle & passing through the lower
neck or junction box to the outside and opened by a tapped lever H at the proper
time and retained open so that about half of the cylinder contents may be displaced
into the second explosive chamber E past the valve G into the mixing chamber F
during part of the in or compression stroke of the piston, the remainder of the stroke
of the piston compresses the charge when it is fired, first in the clearance and then
in the second explosion chamber the charge being expanded during the working
stroke to more than double the volume of gas and air fired for I prefer the exhaust
valve I to close at about one sixth before the stroke ends. The exhaust valve I is
operated by means of the lever J and cam K. The portion of the charge displaced
into the mixing chamber is drawn into the cylinder A by way of the second
explosion chamber E upon the next suction stroke.
Figures 5 and 6 are detail views of the governing arrangements for controlling
the gas valve by a lever L pivotted at one end. One end of a spiral spring M is
attached to the lever L the other end to a fixed stud N. Or the spring M may be
attached to a toothed quadrant P gearing into a pinion Q fixed to the screw spindle
of the gas valve operating same under the action of the spring as hereinbefore
described.
The spring M prevents the lever L or quadrant P from remaining at the dead
point, that is, the utmost extension of the spring M and the slightest movement by
the governor taking it over this point, suddenly and completely cuts off the gas.
Figure 7 shows a method of igniting the charge by means of asbestos fibre, slag
wool, or other incombustible material R placed in a metal chamber S open to the
cylinder by port T, which chamber is kept hot for the ignition of the charge by the
heat supplied to it by the combustion in the combustion chamber.
Figures 8 and 9 are side section and front view respectively of a carbon disc U
with a hole bored through same, or a metal tube V may be inserted as shown.
In Figure 7 the chamber S is a continuation of the channel to the external
igniting tube, and in either figure the charge is compressed into the chamber or
tube to effect ignition as in the external igniting tube, the flame to heat which is
turned off after the engine has become sufficiently heated.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. In explosive gas engines for effecting a double expansion by displacing a
part of the charge, the taking in air alone for about half the suction stroke, thus

page_text: -
preventing the back fire of the displaced portion in the mixing chamber; and the
keeping the gas valve normally open during the half suction stroke.
2. The combination of the second explosive chamber with the construction and
arrangement of parts for displacing about half the cylinder contents, as set forth.
3. The construction and arrangement of parts for governing as described and
shown.
4. The methods described and shown for firing the charge (after the engine has
become heated) without external flame by a tube or chamber fitted within the
explosion chamber into which the charge is compressed as in the external tube
igniter and in a similar way fired at the point of highest compression.
The 16th day of June 1891.
JAMES ROOTS.