Year: 1888

page_text: Date of Application, 26th June. 1888
Complete Specification Left, 26th Mar., 1889
Complete Specification Accepted, 27th Apr., 1889
I JAMES ROOTS 19 St. Marys Road Westbourne Park W. Engineer do hereby declare
the nature of this invention to be as follows:-
The piston is made with the packing rings farther apart than usual. In the casting
of the cylinder an aperture is made about one third of the distance from the end, over
which aperture is bolted a casting forming a globular chamber open to the cylinder, a
channel connects the chamber with the back of the cylinder close to the cover, having
a valve midway. The outstroke of the piston draws in a charge of gas and air, this is
compressed by the instroke a portion of it in the back of the cylinder behind the piston
and a portion in the said chamber, that portion at the back of the cylinder is ignited,
tho piston is impelled forward on its outstroke and on arriving at the opening to the
chamber, the second compressed charge is fired at about a third of the stroke just
when the crank is in the most favourable position for receiving an impulse. If the
said chamber is without communication with the back of the cylinder the first charge
is more compressed than the second. The chamber may be fixed at the back on the
cylinder cover providing the second charge is fired about a third of the stroke and
there is a controlling valve between the two charges.

page_text: JAMES ROOTS, of 19 St. Mary's Road, Westbourne Park, W. Engineer, 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 anu by the following statement:-
The object aimed at and attained in this engine is the maintaining a higher pressure
through a greater portion of the stroke and the effecting this in such a manner as to
economise the ga-.
The piston is made with the packing rings farther apart than is usual. In tho
casting of the cylinder a port or aperture is made at a short distanco from the end,
over which aperture, is holtel a casting forming a chamber open to the cylinder. The
ourstroke of the piston draws in a charge of gas and air, this is compressed by the
instroke, a portion of it in the lack of the cylinder behind the piston and a portion
in the said chamber, that portion in the back of the cylinder is first ignited, the piston
is impelled forward on its outstroke and on arriving at the opening to the chamber
the second compressed charge is fired just when the crank is in a most favourable
position for receiving an impulso. If the said chamber is without communication
with the back of the cylinder the first charge is more compressed than the second.
Figure is a sectional elevation of the engine.
Figure 2 is a part sectional plan.
A is the cylinder. B the piston. (the separate explosion chamber. D the port
in the cylinder communicating with E the ordinary lift admission valve. F the
ordinary bell admission or mixing chamber. G the gas pipe. O the exhaust valve of
ordinary construction. P the ordinary red hot igniting tube.
The Trush charge of gas and air is drawn by the suction stroke from the bell
chamber F, by the valve E through the chamber and the port 1) sweeping before
it the products in the chamber C into the cylinder. The piston B returns compressing
the charge both into the chamber and in the cylinder until the piston covers and
closes the port 1). The piston B continues its stroke, further compressing the charge
in the end of the cylinder A until at the highest compression this portion is fired by
the red hot tube P. The piston B then returns on its outstroke and on reaching the
port D the richer charge in C is also fired, and the piston continues its working out-
stroke with an increased pressure during that portion of the stroke from which greater
mechanical advantage is obtained i.e. when the crank is at or near right angles
with the connecting rod.
This arrangement pormits of the soparate explosion chamber becoming extremely
licated without increasing the friction or affecting the lubrication of the piston, the
timo of the second explosion being determined by the distance of D from the end of
the stroke.
On the exhaust instroke, the exhaust valve O is closed immediately after the piston
has covered the port and the romaining exhaust products are compressed by that
portion of the instroke and allowed to expand again until the piston in its out-
stroke uncovers the port D when the suction commences.

page_text: In my Provisional Specification I give about one third of the outstroke as the
distance of the port 1) from the end of the compression stroko but I find that the
distance will vary in Engines of different size. The two charges may be connected
by a tube of small bore, one end being screwed into the chamber C, the other
into the cover, being connected together by an union joint having a channel or
channels sufficiently narrowed to prevent the passage of flame but allowing the
passage of the gases under pressure, in which case the compression in both
chambers is always rapidly equalised, but I prefer to make the Engine as shown
in the drawing, in which case the compression in the cylinder end is about double
that in the chamber C, and is about 80 lbs. to 45 lbs. respectively.
I disclaim the arrangement mentioned in the provisional specification of placing
the chamber on the cylinder cover as it would not be an economical arrange-
ment.
I am aware that separate explosion chambers have been used in Gas Engines
before. I am also aware that Gas Engines have been constructed in which separate
consecutive explosions have occurred in one outstroke, notably that described in the
Patent Specification of Matthew Piers Watt Boulton, No.3767 and dated September 27th
1876, in which three separate annular chambers were formed round and in the
cylinder and which were in turn opened by the piston in its outstroke. This arrange-
ment gives a much greater cooling surface for the explosive charge, a difficulty of
properly lubricating, and increased friction in passing the piston rings over each
chamber. In my improved Engine, these disadvantages are removed, causing a
great economy of gas.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that I do
not claim a separate chamber or a second explosion in one outstroke but what I
do claim is :-
1. In explosive gas motors, a second explosion chamber communicating with the
cylinder by the port D, which port is opened and closed by the movement of the piston
for the purpose and as described and shown.
2. In Gas Engines having a second explosion chamber, drawing the whole charge
through the second or separate explosion chamber, sweeping out the products therein,
so that the second charge is much the richer of the two, as described.
3. In an explosive gas motor, the combination of the cylinder A and piston B with
a chamber, such as C, admission valve E, and chamber F.
The 26th day of March 1889.