Improvements in Igniting Apparatus for Gas and Oil Motor . Engines.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
Improvements in Igniting Apparatus for
Gas and Oil Motor
.
Engines.
I, FRANCIS WILLIAM CROSSLEY of Openshaw, near Manchester in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:
Ignition of the charge in the cylinder of compression gas or oil engines is
conveniently effected by communication with the interior of a heated tube. The time
of such communication may be governed by either slide or lift valves but lift valves
are generally preferable. Such valves however are liable to, leak, and this may cause
premature ignitions, deranging the working of the engine, and tending to reverse
the direction of rotation particularly at the starting of the engine.
My invention relates to the construction and working of lift valves in such a
manner as to avoid the risk of premature ignition resulting from leakage past the valve
or from too early communication being made at starting. Whatever be the special
construction of the ignition valves employed for opening and closing communication
between the engine cylinder and the heated tube I always so arrange them that the
passage leading to the igniting tube remains open to the atmosphere or to a space in
which there is no combustible fluid and closed to the cylinder containing a combus-
Then by a movement of the
tible charge until the time for ignition almost arrives.
valves the former communication is closed and the tube is put in direct communication
with the cylinder containing the charge.
As this prevents the entrance of combustible fluid into the igniting tube before the
desired time, the moment of ignition is thus safely controlled.
According to an arrangement applicable to a single motor engine I place in a
cylindrical cavity a.stem having at each end a lift valve. When this stem is moved
by a spring toward one end of the cavity, one of these valves is seated closing com-
munication between the engine cylinder and the igniting tube, and leaving the other
valve open so that there is communication between the atmosphere and the tube.
When the stem is moved by the cam in opposition to the spring toward the other end
of the cavity, the passage to the air is closed and that to the engine cylinder is
opened. Thus when the valve to the cylinder is closed, that to the outer air is

page_text: open and consequently should any combustible fluid leak past the lift valve next the
cylinder, it is free to escape without entering the heated tube and therefore without
causing premature ignition in the cylinder.
If it be desired to prevent escape of combustible gases to the atmosphere during
the moment between the opening of the valve communicating with the cylinder and
the closing of the other, a piston may be formed on the stein of the valves so as to
block the cylindrical cavity between the valves. This piston being between the
passage leading to the igniting tube and the cylinder valve when the latter is shut,
leaves the passage between the igniting tube and atmosphere at this time open.
When the movement of the valves and piston takes place, the pisiton passing to the
other side of the passage leading to the igniting tube, opens its communication
with the cylinder and closes that to the atmosphere, at no time permitting a free
passage between the cylinder and atmosphere.
I employ a somewhat similar arrangement of igniting valves for twin engines in
which there are two cylinders side by side, having the strokes of their pistons so
timed that when the one is compressing a charge, the other is expelling products of
previous combustion. In this case, the two lift valves connected together by a piston
stem as above described, seat respectively on passages leading to the two cylinders,
and between these seatings there is a single passage to the heated tube which
serves for ignition of the charge in both cylinders. When the piston in the
one cylinder is compressing the combustible charge therein, the one valve closes
the passage to that cylinder the other valve being then open. If any combustible
fluid should leak past the closed valve it is free to pass to the other cylinder
(where there is no combustible) without entering the heated tube. When the
moment for ignition comes, the valves are shifted so as to close the passage
formerly open and to open the passage to the cylinder which contains the com-
pressed charge. A portion of this charge then entering the heated tube is ignited,
and the ignition is communicated to the charge in the cylinder. As a convenient
means of working the valves in this arrangement, 1 employ a cam having a path in
which a roller on an elastic lover is engaged, this lever being linked to the stem of
the two valves, so that as the cam revolves the valves are moved to and fro. I make
the cam path such that the stroke given by it to the lever is greater than that
required by the stroke of the valves, and thus the lever is bent at each stroke and
acts as a spring to keep the valve in case each closed.
My invention further relates to means of varying the time of communication
between the cylinder and the igniting tube. This by preference should take place
considerably later at starting than during ordinary working. For this purpose, I
provide a double stepped cam for giving motion to the valves.
It is fitted to slide on but to turn with the shaft that works the supply and dis-
charge valves. One of these cam steps is set in advance of the other, the one being
timed for the regular working of the engine the other for the starting. The cam
can be slid into position for either step acting on the ignition valve lever, but in
order to ensure that the right step shall act under each of the two working
conditions, 1 connect this cam to that which works the exhaust valve, this latter cam
baving a step or projection which is brought into play during the starting of the
engine to release a portion of the charge during the compressing stroke, and thus
to reduce the labour of moving the engine by hand against full compression of the
charge. As the attendant in starting must use the exhaust cam in this way, he
must at the same time use the later step of the ignition cam, but when the engine is
started and the exhaust cam is shifted so that it no longer releases part of the
charge, the ignition cam is necessarily shifted with it so as to bring its earlier step
into action giving the required lead to the ignition.
Dated thin 10th
CL 1000
ABEL & IMRAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION..
Improvements in Igniting Apparatus for Gas and Oil Motor
Engines.
I, FRANCIS WILLIAM CROSSLEY, of Openshaw near Manchester in the County of
Lancaster, 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:-
In gas or oil motor engines, in which the charge is compressed before it is fired,
the ignition of the compressed charge is conveniently effected by opening com-
munication from the cylinder to the interior of a heated tube or to an igniting
or incandescent body. The time of opening this communication may be governed by
slide or lift valves. Should there happen to be a leakage past such lift valves, which
are generally preferable to slide valves, a premature ignition may ensue deranging the
working of the engine and tending to reverse it, particularly at the starting of the
engine.
My invention relates to the construction and working of ignition valves of the lift
valve kind in such a manner as to avoid risk of premature ignition resulting from
leakage past the valves or from too early communication with the heated tube or
iguiting body at the starting of the engine.
Whatever be the special construction of the ignition valves, I always so arrange
them that the passage leading to the heated tube or igniting body remains open to
the atmosphere or to a space that contains no combustible fluid and closed to the
cylinder containing the combustible charge until the time for ignition almost arrives,
whereupon by a movement of the valves, the former communication is closed and
the cylinder is put in communication with a heated tube or other igniting body.
As this arrangement prevents combustible fluid from entering the heated tube
or coming in contact with the igniting body before the desired time, the moment
of ignition is thus safely controlled.
In the accompanying drawings I show several arrangements of ignition valves
according to my invention as I will now describe, employing as far as possible the.
same reference letters to indicate corresponding parts in the various figures. I show
these valve arrangements in connection with a heated tube, but it may be readily under-
stood that similar arrangements can be used to govern communications to a chamber
containing an igniting or incandescent body, such for instance as a heated platinum
wire, instead of a tube.
Fig. 1 is a vertical section, Fig. 2 is a front view and Fig. 3. is a plan partly in
section shewing an arrangement of ignition valve which is opened by the descent of a'
spring lever L worked by a cam. T is the ignition tube which is situated within a refrac-
tory casing R and is heated by the flame of a burner B. The tube communicates by a
passage P with the valve box D from which there is a passage C, to the engine
cylinder, and another passage A to the open air or to a space containing no com-
bustible. A double ended piston valve E works in the valve box D. It is usually
'

page_text: kept up by the spring S with its upper end seated, closing the passage C from the
cylinder but leaving a free passage from P to A. When the lever L descends the
piston E descends, first closing the passage P and then seating with its lower end
so as to close the passage to A whilst it again opens P to C, thus putting the heated
tube in communication with the cylinder. Beyond the passage P is provided a
chamber Fin which products of previous combustion are compressed by the portion
of fresh charge coming from the cylinder. It is not necessary that the valve stem E
should be a piston fitting the valve box, but it is preferred to make it as a piston
which closes P except when the valves are at either extreme of their stroke.
Fig. 4 is a vertical section Fig. 5 is a front view and Fig. 6 is a plan partly in
section of an igniting valve arrangement in which the lever Lusually keeps up the
double valve E the upper stem of which acts as a piston valve closing the passage C
to the cylinder during compression of the charge. The lower stem of the valve is
shaped as shewn at Figs. 18 and 19 which are sections taken respectively at A¹ and B'.
On the descent of the lever L at the moment of ignition the spring S depresses E on
its lower seating, closing the passage to A and opening that from to P. An
additional chamber G may be provided to receive gascous residues of previous com-
bustion such as would interfero with ignition. The upper stem of E may merely fit
the passage in D above it as a piston or plunger, as shewn in Fig. 4, or it may be
made to seat as a valve as shewn in the part section Fig. 4. In this case the end
of the lever L is provided with a spring H which yields a little when E is pushed
up against the upper seating. The lever is worked by a cam in the usual way.
Fig. 7 is a vertical section. Fig. 8 is a front view and Fig. 9 is a plan of an
arrangement in which two separate valves E and e, with their stems abutting on each
other, govern the passages to A and C respectively. Fig. 7 shews their position at
the moment of ignition. During compression of the charge the valve e is closed and
the valve E is held open by the lever L which is worked by a cam.
ignition, the cam releases the lever L, and the spring S causes it to ascend closing the
valve E and opening e thereby putting C in communication with P.
At the time for
Figs. 10 to 15 inclusive shew an arrangement for ignition of the charges of the
two cylinders of a twin engine, one heated tube or other igniting appliance serving
for each alternately. Fig. 10 is an end view and Fig. 11 is a sectional plan, Fig. 12
shews separately the igniting lever L and the cam K which works it. Fig. 13
is a sectional plan of the bearing in which the lever L is pivotted. Fig. 14 is a
sectional plan to an enlarged scale of the ignition valve and the passages which it
governs. Fig. 15 is a cross section of the middle of the valve stem.
VIV are the
two cylinders, U₁ U² their respective exhaust valves. On the countershaft M is fixed
the cam N which by means of the levers 0'02 work the charging valves QQ² of
the two cylinders, and on this shaft M is also fixed the cam K which moves the
igniting lever L keeping it up as shewn in Fig. 12 during nearly half a revolution
and keeping it down for nearly half a revolution. The upright arm L' is bent over
at the top, its bent end L² engaging between the collars of the valve E. While
the valve end E2 is closing the passage to the cylinder in which the charge is
undergoing compression the passage P is in free communication with the passage C,
to the cylinder in which there are incombustible gases resulting from previous
combustion. When the valve is shifted, El is seated and E2 is unseated opening
communication from C2 to the passage Pleading to the heated tube or other
igniter. The stroke given by the cani K to the lever L is somewhat greater than
is permitted by the stroke of the valves E¹ E2, and the lever L is made elastic so
that being a little bent at each stroke it acts as a spring keeping each valve close
home to its seat except at the moment when it is shifted to effect ignition. Instead
of making the lever L elastic play may be left for L2 between the collars of the
stem of the valves E' E' so that the pressure acting on the one of these valves to
open it serves to keep the other closely seated.
When the engine is first started, the communication for effecting ignition should
be opened later than when the engine is working at normal speed. Also, in order to
facilitate the starting of the engine, it is desirable to open the exhaust valve during

page_text: part of the compressing stroke, so as to relieve to a certain extent the labour that would
attend full compression of the charge. In order to provide for those conditions and
to ensure safety at starting the engine without risk of premature ignition, I employ
the connected arrangement of gear for the exhaust and ignition valves shown in end
view in Fig. 16 and in part plan in Fig. 17. On the countershaft M I fit with a
sliding feather two cams X and Y which are joined together and can be slid
longitudinally on the shaft M' by a hand lever m to either of two positions, in each
of which the cams are retained by a round ended spring stud m' entering a counter-
sunk in the shaft M. The cam face by means of a lever X' normally opens the
exhaust valve X2, but, besides this face there is a step 1, indicated by dotted lines
in Fig. 16, which, when it acts on the roller of X, also opens the exhaust valve for a
short time during the compressing stroke. On the cam Y the face y by means of the
lever normally works the ignition valve which may be such as I have described
with reference to Figs. 4 to 6 inclusive. But there is on the cam Y a step y' which
acts on the roller of Y' so as to prevent the ignition valve from being opened till a
point of the revolution later than that at which the face Y would cause ignition.
At the starting of the engine the cams X and Y are shifted together by the lever m
to the position where the steps r¹ and y' are brought into action the one relieving the
compression labour and the other causing ignition later. When the engine attains
speed, the cams are shifted to the normal position, the faces & and Y then acting in
the usual way. Instead of moving the cams along the shaft as above described, the
levers or the rollers which bear against the cams may be shifted laterally so as to
be acted on by the steps x and y for starting and by and Y during normal working.
Although I have shewn and described this connection of the exhaust and ignition
valve gear as applied to ignition valves of the kind previously described, obviously a
similar connection of the gear may be employed when the ignition valves are of other
kinds worked by cams which can be connected with the exhaust cams.
Having thus particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I would have it understood
that I make no general claim to the use of a heated tube or other incandescent body.
for effecting ignition, nor to valves for governing the passages to and from the igniting
chamber, but what I claim is :—
1. The arrangement of ignition valves substantially as described with reference to
Figs. 1, 2 and 3 of the accompanying drawings.
2. The arrangement of ignition valve, substantially as described with reference to
Figs. 4, 4, 5 and 6.
3. The arrangement of ignition valve, substantially as described with reference to
Figs. 7, 8 and 9.
4. The ignition apparatus adapted to a twin engine substantially as described with
reference to Figs. 10 to 15 inclusive.
5. Connecting the cams for working respectively the exhaust valve, and the ignition
valve, and providing them with steps which are brought simultaneously into action for
relieving compression and delaying ignition at the starting of the engine, substantially
as described with reference to Figs. 16 and 17.
Dated this 10th day of December 1888.