Improvements in Gas Engines.
Year: 1888

page_text: Date of Application, 9th Nov., 1888
Complete Specification Left, 9th Aug., 1889-Accepted, 2nd Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in Gas Engines.
I JAMES ROOTS 19 St. Marys Road Westbourne Park W. Engineer do hereby
declare the nature of this invention to be as follows:-
The
The objects of this invention are the economy of the explosive gas used in the
engine, a simple arrangement for governing, and a method of easily starting.
engine draws in a charge of gas and air, compresses it into a chamber at the back
of the cylinder and also into the clearance space so that the charge is about equally
divided. That portion in the clearance space is then fired, the piston nakes an
outstroke and when near the end of it a portion of the combustion products are let
out the piston returns compressing the products until near the end of the instroke,
when the valve between the chamber and cylinder is opened by a cam or other
suitable means, off the exhaust-valve shaft and the charge in the chamber is fired
impelling the piston on another outstroke, on the return instroke it exhausts and
again draws in a charge. There are two working strokes to one each of suction and
compression. The cycle is suction, compression, explosion, compression, explosion.
exhaust, when the suction commences again.
A spring curved tube such as is used in a Bourdon pressure gauge is fixed on the
outside of the cylinder toward the front end, having a small hole or valve com-
municating with the cylinder, so that the pressure within expands the tube and the
more frequent the explosions the more it expands or straightens, the gas being prevented
from freely escaping and the lifting or straightening is used to cut off or lessen the
supply of explosive gas, thus governing the speed. An elastic disc may be used in
place of the Bourdon spring.
A hole is bored through the wall of the cylinder, or cover, or chamber, into which
is fixed a bearing having a hollow sliding rod passing through it and closely fitting
it, on the end of the rod inside the cylinder is a collar having a valve surface seated
against the bearing with a spring on the outside to keep it down on the seating. It
is very much like a small spindle valve with a large hollow spindle. After having
drawn in half a charge uncompressed, a lighted match or a piece of lighted tow or
cotton waste dipped in paraffin, is placed in the cavity of the sliding rod, and by hand
forced quickly into the cylinder, setting fire to the charge and starting the engine.
A modification of this arrangement is made like a cock or tap with only one opening
to the cavity in which the lighted match is placed and the cock or tap being quickly
turned brings the cavity with the light opposite an opening to the cylinder and fires
the charge. To fire the charge when under compression I attach a chamber about
the size of an orange, communicating with the inside of the cylinder having a tap
between to close communication, and an aperture in the side of it covered by a trap
door which being worked by the tap is always open when the tap is closed and vice
On the tap being opened a portion of the charge flows into the chamber, the
tap is then closed and the gas in the chamber is ignited with a match, on the tap
being opened the flame is carried to the charge in the cylinder.
Tho said small
chamber may also be attached to either the sliding cavity or the revolving cavity
before mentioned. In engines in which the charge is fired by a red hot igniting
tube 1 place a small tap or valve at the end of the igniting tube and the charge is
fired by allowing a small portion of the compressed charge to flow through the tube
and suddenly closing it again.
versu.
Doind November 8th 1000

page_text: COMPLETE SPECIFICATION.
Improvements in Gas Engines.
I, JAMES ROOTS, of 19 St. Mary's Road, Westbourne Park, Middlesex 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 and by the following
statement:
The object of this invention is the economy of the explosive gas used in the Engine.
The Engine draws in a charge of gas and air compresses it into a chamber at the
back of the cylinder and also into the clearance space, so that the charge is about
equally divided. That portion in the clearance space of the cylinder is then fired,
the piston makes an outstroke and when near the end of it a portion of the combustion
products are let out, the piston begins to return when the valve between the chamber
and cylinder is opened by a lever actuated by a cam on the exhaust valve shaft, the
pressure then in the chamber being greater than that in the cylinder, the charge flows
in, displacing more of the exhaust, the exhaust valve then closes and the second half
charge, together with the remaining products is compressed and fired impelling the
piston on another working outstroke, on the return instroke there is a full exhaust
stroke and on the next outstroke the piston again draws in a full charge, the series of
operations being repeated.
There are two working strokes to one full or complete stroke each of suction and
compression. The cycle is, outstroke, full or whole-stroke suction, instroke, wholestroke
compression, outstroke, explosion and working stroke with half the charge, instroke,
part exhaust and then compression of the remaining part of the charge with the
remainder of exhaust products, outstroke, explosion and second working stroke,
instroke, wholestroke exhaust and again wholestroke suction. This arrangement gives
double the expansion and therefore an economy of the gas.
The other devices for starting etc, mentioned in the Provisional Specon I abandon.
Briefly, this invention consists in effecting double expansion by dividing the charge,
by means of a chamber, into which is returned from the cylinder about one half the
charge, during the stroke following the suction stroke, one part only being fired at a
time. There is no tendency to produce a vacuum. Dividing the charge, per se, is not,
new. In the Drawings the same letters refer to the same parts in all the Figures.
Figure 1 is a side sectional elevation; Figure 2, a half sectional plan; Figure 3 a
half end elevation of the engine; Figure 4 shows a modification; Figure 5 shows a
one-to-two arrangement giving the double expansion. A is the cylinder, B the piston,
C the chamber for receiving half the charge, A' the cylinder inlet port, A² the
cover, the valve closing communication between the chamber and cylinder, D' the
stuffing box through which the spindle of the valve D passes; D2 the lever which
opens or raises the valve D by means of the cam D³. E is the inlet valve to the
chamber which also covers the gas orifices E, F the first exhaust valve opened by the
lever actuated by the cam 2, G the second exhaust valve opened by the lever G'
actuated by the cam G2, H the exhaust valve shaft which is revolved once to every
three revolutions of the crank shaft by means of ordinary gear wheels; I is the usual
igniting pipe kept at a red heat by an ordinary atmospheric gas burner and enclosed
in an asbestos lined tube, and the other parts not shewn are of the usual
construction.
The valve E may also if desired be opened during the suction stroke by a lever
and cam on the one-to-three shaft, but it is not necessary and is not shown.
The cylinder inlet port A¹ is made sloping or inclined so as to direct the charge
away from the exhaust valve G. The exhaust valve G is placed up as closely as
possible to the surface of the cylinder as any space here would cause a waste of
pressure during the working outstroke.
The valve seating and box are fitted into the port cast in the cylinder side.
The suction outstroke of the piston B draws in a charge of gas and air through the
chamber by the two valves D and E, the valve D being opened by the cam D³,

page_text: the valve E by atmospheric pressure; at the commencement of the compression
instroke the valve E closes, the valve D being kept open by the cam during a part
of the instroke, a portion of the charge is returned to and compressed into the
chamber C, as well as in the cylinder and clearance space, when the valve D is closed
the half charge in the cylinder is further compressed and exploded doing a full
working stroke and having a double expansion, the chamber having about half
the cubic space of the whole piston stroke: close to the working stroke end, the
exhaust valve G is opened and a part of the exhaust let out: near the dead point
the valve D opens by its cam D³ which has two bosses or prominences or by the
pressure within the chamber C and the half charge then pours into the cylinder
displacing more of the exhaust during the instroke until the piston has covered the
exhaust port of the valve G which then closes, and during the remainder of the instroke
the second half charge is compressed together with the remaining products and fired,
performing the second working stroke with double expansion, at the end of which
the first exhaust valve F is opened by its cam F2 and the cylinder, (except for the
very small clearance space allowed) is completely exhausted on the instroke, and the
series of operations commences anew.
The pressure in the chamber C will vary according to the number of revolutions
and the temperature of the cylinder walls.
In Figure 4 is shown a section of the cylinder end of a modification in which
the second exhaust port and valve G is dispensed with and a curved shield or bafe
plate S screwed to the cylinder cover A2 is employed to direct the incoming charge
of explosive compound away from the exhaust valve F when the valve D is opened,
the cam F being made with two bosses or prominences to open the valve F twice
in the three revolutions, the first opening operating in lieu of the opening of the
valve G and the rest of the Engine having the same construction. I prefer the
former arrangement with two exhaust valves or ports as a portion of the new charge
is less likely to find its way out of the exhaust valve with the exhaust products.
Figure shows another arrangement which effects the same object i.. double
expansion of the half charge but without the compression of the half charge in the
chamber C. The exhaust valvo shaft revolves in this case one to two of the crank
shaft and the second exhaust with the port and valve is also dispensed with.
The chamber C is open to the air at the bottom through wire gauze and the gas
orifice is at T, but the previously described closed chamber can also be used with
this arrangement. The piston B draws in an explosive charge into the cylinder A,
through the chamber Cand inlet port A¹ the valve D being lifted by the cam D³
which in this case has only one boss by means of the lever D, it is also kept lifted
by the cam on the return instroke during half the stroke, so that half the charge is
returned to the chamber C, the half charge in the cylinder A is then compressed and
fired, doing a working stroke, the return or instroke of the piston exhausts by the
valve F opened by the lever as before described, and on the next outstroke a whole
charge is again drawn in, about half of which is again returned to the chamber C, the
series of operations being repeated. The governor may be made to control the time
of closing the valve D, so that the charge left in the cylinder when compression
commences may vary from half to a third or two thirds, by acting directly upon the
cam D³.
In the three-to-one arrangement Figs. 1, 2, & 3 it is evident that by timing the
cam D to retain the valve D open later in the second instroke, the second portion
would be fired in the chamber C'as well as in the clearance space, but this heats the
valve D excessively; it is also evident that the exhaust port of the valve G could be
used without the valve when placed closer to the end of the outstroke.
This invention may be duplicated in one engine.
Having now particularly described and ascertained the nature of my said inven-
ion and in what manner the same is to be performed, I declare that what 1
claim is :-

page_text: whereby the cylinder inlet valve placed between the cylinder and the chamber is
retained open during about half the instroke following the suction outstroke so that
about half the charge only is fired at each time thus allowing it double the expansion,
as set forth.
2. In an explosive Gas Engine the chamber C for receiving about half the charge
drawn in the cylinder during the suction stroke and this portion of the chargo being
compressed in the chamber C assists in displacing the exhaust products in the
cylinder, as set forth.
3. In an Explosive Gas Engine the method of working with two working strokes
in three revolutions, each allowing double expansion, substantially as described.
4. The combination and arrangement of mechanism for producing two working
strokes in three revolutions, substantially as described and shown herein.
5. The modified arrangement, as described with reference to Figure 4.
6. In an explosive Gas Engine the chamber Copen to the air for receiving un-
compressed the portion of the charge displaced by the piston on its instroke, there
being a working stroke every other revolution.
7. The method of working and arrangement of parts, as described and shown in
Figure 5.
The 0th day of Awenst 1880
H. GARDNER,
166, Fleet Street, London, Agent for the said James Roots.