Improvements in Internal Combustion Engines.
Year: 1897

page_text: Date of Application, 9th Sept., 1897
27th Au
1808
PROVISIONAL SPECIFICATION.
Improvements in Internal Combustion Engines.
JAMES ROOTS, Engineer, 100, Westminster Bridge Road, London, do hereby
declare the nature of this invention to be as follows:-
A relatively small cylinder is attached for igniting to the cover of the engine,
with its axis parallel to the working cylinder, and on one side of it, in which
a piston is reciprocated by means of an excentric on the crank shaft or on the
usual half speed pin. In the piston which may be hollowed out or tubular for
a portion of its length, is provided a port, which registers with another port in
the small cylinder, and which also passes through the cover into the clearance
space of the engine. These ports are similar to those described in my Speci-
fication 2138 of 1896 as applied to an igniting piston and cylinder. The end
of the cylinder may communicate by means of a small admission valve or other-
wise with any channel of the engine which contains unexploded mixture free
from products.
The small igniting piston and cylinder attached to the cover or connected with
the clearance space, may have separate suction and exhaust valves, the exhaust
valve of which may be operated by the same gear which operates the exhaust
valve of the engine, and the igniting piston is then operated by an excentric.
The excentric may have attached to it for starting a handle or lever.
Instead of the usual mushroom valves a cylindrical piston valve provided
with rings may be used, having ports registering at the desired times, with ports
in its casing or cylinder for effecting admission and exhaust of the working
cylinder. This piston valve may be operated by means of a cam fitted on the
crank shaft, having a figure of 8 or "return and cross groove" cut upon its
peripheries, one half of the being cylindrical and centric or thereabout with
the shaft, the other half cam-shaped and excentric. A slide or two rollers fitted
on the reciprocating shaft runs in the groove. Both the igniting piston and
valve piston may be operated by the same rod, and in small engines, both the
ignition and admission and, exhaust may be effected by the one piston, having
igniting ports such as those in the before mentioned specification.
Dandamhan 0th 1907

page_text: be performed, to be particularly described and ascertained in and by the following
statement: —
A relatively small cylinder is attached for igniting to the cover of the engine
with its axis parallel to the working cylinder and on one side of it in which a
piston is reciprocated by means of an eccentric on the crankshaft or on the usual
half-speed pin. In the piston which may be hollowed out or tubular for a portion
of its length is provided a port which registers with another port in the small
cylinder and which also passes through the cover into the clearance space of
the engine. These parts are improvements upon and similar to those described
in my Specification 2138 of 1896 as applied to an igniting piston and cylinder.
The end of the cylinder may communicate by means of a small admission valve
or otherwise with any channel of the engine which contains unexploded mixture
free from products.
The small igniting piston and cylinder attached to the cover or connecting
with the clearance space may have separate suction and exhaust valves the
exhaust valves of which may be operated by the same gear which operates the
exhaust valve of the engine and the igniting piston is then operated by an eccentric.
Instead of the usual mushroom valves a cylindrical piston valve provided with
rings may be used having ports registering at the desired times with ports in its
casing or cylinder for effecting admission and exhaust of the working cylinder.
This piston valve may be operated by means of a cam fitted on the crankshaft
having a figure of 8 or return and cross groove cut upon its peripheries, one
half of the cam being cylindrical and centric or thereabouts with the shaft, the
other half cam-shaped and eccentric. A slide or two rollers fitted on the recipro-
cating shaft end runs in the groove. Both the igniting piston and valve piston
may be operated by the same rod, and in smaller engines both the ignition and
admission and exhaust may be effected by the one piston having igniting ports
such as those in the before mentioned specification.
Fig. 1 shows an engine having its igniting piston with a hollow trunk having
ports (1) for the passage of the igniting flame to the working charge and (2) for
the passage of the exhaust.
Fig. 2 is an engine upon the one revolution cycle with an igniting piston and
cylinder.
Fig. 3 shows a modification without a hollow trunk igniting piston.
Fig. 3 is a diagram indicating the relative timing of the working and ignition
pistons.
Fig. 4 is a section on the line 1, 2, of Fig. 3.
Fig. 5 is a modification in which the ignition piston may serve also as a gas
pump, or to supply additional air.
Like letters refer to like parts in all the figures.
A is the working cylinder, B the working piston, C the ignition and valve
cylinder, D the ignition and valve piston. E the admission valve, F the exhaust
port, G the port in the piston D registering with F. H the port registering with
the port I leading to the working cylinder. J indicates the position (not rightly
shown in this section) of the ignition tube which may be used at starting especially
in an oil engine. K indicates the position of the vapouriser in an oil engine or
ignition tube casing in a gas engine, and K₁ the port leading to the admission
valve from the vapouriser or in the case of a gas engine from the gas inlet pipe,
or gas valve.
Referring to the position shown in Fig. 1. ignition of the working charge in
the main cylinder A has just taken place through the port I, and the piston B
moves outward on the working stroke. The piston D also moves outward until
the exhaust port F is opened by the piston bringing its port G opposite F. The
working cylinder is then exhausted through the port F; immediately on the
closing of port F by the piston D, the suction commences through the valve E,
the piston B drawing in a charge of oil vapour and air or air and gas by the
port I to the working cylinder. The two pistons then move inward compressing

page_text: the charge and upon the closing of the port I, the piston D compresses the charge
remaining in the ignition cylinder to a high degree of compression preferably
sufficient to ignite it without the assistance of any external heat. In either a
gas or oil engine but particularly in the latter it may not be desirable to do this
at starting, in either case it would require a higher compression when cold to
ignite the charge than after a few ignitions had occurred to heat the surrounding
metal. For starting the engine therefore an ignition tube J is provided, the
position of which (though not correctly shown in this section) is indicated in
Figs. 1, 2, 3, 4, and 5. After the cylinder is hot, the flame heating the ignition
tube is turned out and the charge is ignited. by compression in the hollow tubular
piston in Figs. 1 & 2, and in the ends of the cylinders C in Figs. 3 & 5, between
the admission valve E and the piston D. In Fig. 1, as the valve shaft P makes
one revolution for every two revolutions of the crankshaft Q, therefore the
piston D makes one stroke for every two strokes of the piston B. In Figs. 1 & 2,
ignition takes place in the cylinder C and within the hollow tubular piston D
just prior to highest compression therein and on the port H opening to the port I
the flame passes through and ignites the working charge in the cylinder A. The
ignition piston continues to operate in Fig. 1, as before described.
In Fig. 2, is shown the arrangement of piston for ignition only when not used
as a valve for controlling the exhaust, and when applied to an engine having
an impulse every revolution and firing at every outstroke when the governor
does not cut out. The exhaust port shown in dotted lines is in the working
cylinder wall at F.
In this case the piston D moves almost synchronously with the piston B, and
the piston rod of the one may be operated by the piston rod of the other in any
known manner instead of being connected to the disc crank pin shown on the
crankshaft Q of the engine Fig. 2, as both pistons make the same number of
strokes. On the opposite or crank side of the piston B in this engine in the
usual well-known manner air is drawn into the crank chamber (not shown),
compressed therein and delivered by a connecting pipe through the valve E to
the cylinder C and through the port I to the working cylinder A. In the case
of an oil engine the air may be first passed through a closed vapouriser in the
position indicated at K, Figs. 2 & 4, surrounding the ignition tube thence to the
port indicated at K₁ leading to the valve E.
On the return of the piston D, Fig. 2, the charge remaining in the cylinder O
is compressed to a high degree of compression sufficient to ignite it and when
the port H registers with the port I at the highest compression, the flame passes
from the cylinder C to the cylinder A.
In Figs. 1, 3, and 5, the engine (of which a part is shown) is arranged to
work upon the ordinary or de Rochas cycle. In Fig. 3, the working piston B
is shown shortly after the commencement of the exhaust instroke with the exhaust
port F open, both pistons continue their inward stroke so that when the working
piston B has reached the end of the instroke the port F will be covered by the
piston D. While the piston B performs the suction outstroke the piston D is
moving forward on the instroke, and when the inward compression stroke of
the piston B commences the piston D is about to close the port I leading to the
working charge. The continued movement of the piston D now compresses to
a high pressure the charge remaining in the cylinder C between the piston D
and the valve E and ignites it. At the highest point of the compression stroke
of the piston B the piston D has again uncovered slightly the port I and
At the
the flame in the ignition cylinder passes to the working charge igniting it.
end of the working stroke the piston D uncovers the exhaust port F and the
working continues. In Fig. 3, the movements of the pistons relatively to one
another is approximately indicated, the line with arrows indicating the movement
of the igniting piston while the lettering shows the corresponding stroke of the
working piston. In Fig. 4, the piston of the vapouriser K for an oil engine is
shown. if it be a gas engine the ignition tube and casing are preferably fitted
in a similar relative position so that when the engine is starting cold the tube

page_text: may be heated if desired to commence the ignitions though it must be understood
that a sufficiently high compression may be obtained in the ignition cylinder
to fire the charge without using the ignition tube.
In Fig. 5, the action is similar to that described for Fig. 3 and 4, but an addi-
tional valve W is shown fitted to the piston D, which valve may be used as a gas
valve for a gas engine and is so placed with its spindle in a tubular piston rod
that it may be very conveniently governed by usual mechanism (not shown).
A cam Y is shown in Fig. 5 keyed to the crankshaft Q. A slide or a pair of
rollers run in the figure of 8 groove cut in the cam, so that the igniting piston
may be operated relatively at the desired times. When the slide or rollers (not
shown) are in the centric groove Y¹ the piston valve or igniting piston is not
operated but when the slide moves across to the cam or eccentric groove Ya the
piston or valve is forced upward to ignite the charge by compression. It must
however be understood that the crank and cam at Fig. 5^ is not shown in position
for operating the piston in Fig. 5.
The slide or rollers usually used in grooves of this description operate the side
rod or reciprocating shaft of the engine, in engines having an ordinary exhaust
valve when the slide runs into the groove Y2 of the larger diameter and eccentric
the exhaust valve is opened and is closed during the time the slide runs in the
smaller groove Y¹, this cam therefore would be useful only for the ignition
piston as shown in Fig. 2, when used for the two revolution or de Rochas cycle,
and with an ordinary exhaust valve.
No water jacket is shown applied to the cylinder C but it will be understood
this is easily added if desired.
The diagram Fig. 3ª applies only to the movements of the pistons as shown in
Figs. 3 & 5.
In Fig. 2 with a working stroke every revolution if the engine be used as an
oil engine it will require a closed vapouriser to convey the oil and air under
pressure from the pump, reservoir or crank chamber to the valve E, but in engines
upon the de Rochas cycle the vaporiser will be, of the Roots open type.
The great advantage of the position of the main admission valve E will be
evident, as the new explosive charge for the working cylinder must necessarily
all pass through the cylinder. C so that explosive charge free from products remains
in the end of the ignition cylinder, thus not only ensuring ignition when firing
by compression but also when starting with the ignition tube. Gas engines
will require a much higher ignition compression than oil engines in the cylinder C
especially in the arrangement as shown in Figs. 3 & 5.
An additional air valve may be used in the ordinary way in engines upon the
dé Rochas cycle which use would not affect the action of the admission valve E.
It must be understood that the short shaft P is of ordinary arrangement with its
gear wheels, but is placed at right angles with the crank shaft and is provided
with an eccentric not shown to work the rod of the piston; although a pair of
ordinary two to one gear wheels may be used having a pin in the learger gear
wheel to which the piston rod is attached.
It will also be understood that the ignition cylinder may be used in de Rochas
cycle engines without the exhaust port F and with an ordinary exhaust valve.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is;-
1. In an internal combustion engine the combination with the working cylinder
and piston of a small ignition cylinder and piston, which ignition piston is operated
by means of an eccentric or pin working either at half speed or at the same
speed as the crankshaft and which has the port H or its equivalent that registers
with another port in the cylinder at or near the highest compression.
2. In an internal combustion engine the combination of the working cylinder
and piston with the ignition cylinder and piston and the admission valve for the
working cylinder substantially in the manner shown.

page_text: 3. Arranging the admission valve for the working cylinder at or near the cover
of the ignition cylinder for the purpose described.
4. In an internal combustion engine a small cylinder and piston firing by
high compression a small charge to be employed for the ignition of the main
charge, provided with a port such as For à port such as G for exhausting the
waste products.
5. Providing a small additional cylinder outside the working cylinder with
an ignition tube to fire the charge in the working cylinder, especially at starting.
6. The combination of the working cylinder, the ignition cylinder with the
valve E, and an ignition tube.
7. In an internal combustion engine a small piston and cylinder, not used
as a power cylinder, operating as a valve for the working cylinder and piston,
provided with exhaust port, admission valve, and ignition tube.
8. In an internal combustion engine having a working stroke every revolution,
an additional piston and cylinder for firing the charge by high compression, the
port from which admits through the cover or to the combustion chamber of the
working cylinder.
9. In an internal combustion engine having an ignition piston and cylinder
and a working stroke every revolution, arranging the valve through which enters
the air or charge from the pump or reservoir or crank chamber, on the end of
the ignition cylinder; with or without an ignition tube to be used if desired
for starting.
10. In an internal combustion engine the combination of an ignition cylinder
and piston having the main admission valve attached thereto, with a vapouriser.
11. In an internal combustion engine the grooved cam with two diameters
or widths, excentric and centric such as shown in Fig. 5.
12. In an internal combustion engine the improved parts as described and
shown in Fig. 1.
13. In an internal combustion engine the improved parts as described and shown
in Fig. 2.
14. In an internal combustion engine the improved parts as described and
shown in Figs. 3 & 4.
15. In an internal combustion engine the improved parts as described and
shown in Fig. 5.
Dated this Ninth day of July 1898.