An Improved Vapourizing and Igniting Device for Gas and Oil Motor Engines.
Year: 1897

page_text: Date of Application, 12th May, 1897
Complete Specification Left, 11th Feb., 1898-Accepted, 23rd Apr., 1898
PROVISIONAL SPECIFICATION.
An Improved Vapourizing and Igniting Device for Gas and Oil Motor
Engines.
JOHN FIELDING, of Upton Saint Leonards, in the County of Gloucester, Engineer,
do hereby declare the nature of this invention to be as follows:-
The object of my invention is to enable a gas or oil motor engine to be worked
without externally heating the igniting and vapourizing apparatus, except at start-
ing.
With this object I employ a tube, preferably a horseshoe bend, which connects
the combustion chamber to the valve box, so that the highly heated products of
combustion are caused to pass through, and thereby heat the tube to a temperature
greater than would be produced merely by the heat of the explosions.
This tube acts as an igniting tube, and in oil engines it also serves in the
vapourizing of the oil charge; at starting it is heated externally.
In an oil engine a branch pipe, fitted with an air inlet valve, and an oil supply
jet and valve, connects to the horseshoe bend, and a mixture of oil spray and air
are drawn through this branch, and the horseshoe bend, into the combustion
chamber and cylinder, the charge of oil being vapourized as it passes along the
branch, and through the horseshoe bend. As the charge enters the cylinder, it
is mixed with a further supply of air, which is admitted by the main air inlet valve.
By a slightly modified arrangement the oil charge may be vapourized in an
external passage before it enters, along with the supplementary air supply, into
the horseshoe bend.
In other respects the motors may be in accordance with usual practice in such
engines, whether of the two or four stroke cycle kind.
In the accompanying drawing, Figs. 1 and 2, the invention is shewn as applied
to an oil motor, Fig. 1 represents the first described arrangement, A being the
cylinder, B the piston, C the combustion chamber, D the exhaust valve, E the main
air inlet valve, F the horseshoe bend, G the branch pipe, H the air inlet valve
on same, I the oil supply jet, and J is a non-return valve in the oil pipe, K is a
water jacket which surrounds the cylinder, combustion space, and main air inlet
and exhaust valve chambers.
Fig. 2 shews the modified arrangement with external vapourizing passage, similar
letters refer to the various parts as far as they correspond, and L is the air inlet
to the passage G.
An Improved Vapourizing and Igniting Device for Gas and Oil Motor
Engines.
I, JOHN FIELDING, of Upton Saint Leonards, in the County of Gloucester,
Engineer, do hereby declare the nature of this invention and in what manner
[Price 8d.]

page_text: the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
My invention relates to an improved arrangement of the ignition tube for gas and
oil motor engines which is sufficiently heated internally by the combustion of the
charge to enable the heating lamp to be dispensed with.
The advantages of automatic ignition, without the use of a lamp, are of such
importance that engines so fitted are generally preferred on account of their
simplicity, even though, as is well known some sacrifice of efficiency is involved.
This loss of efficiency is due to the employment of a hot combustion chamber
of relatively large capacity holding in fact the great part of the explosive. charge:
The successful working of such engines. depends upon the fact that this combus-
tion chamber presents a large surface to be heated by the explosion, and upon the
fact that it is connected to the water jacketted cylinder only by a small neck, so
as to minimise the conduction of heat from' the chamber to the cylinder. In con-
sequence of the large area of heated surface pre-ignition of the charge tends to
take place, especially under heavy loads, so much so that anything like accurate
firing of the charge at about the dead point is practically impossible.
Another disadvantage arising from the large area of the heating surface is, that
each incoming fresh charge is dilated to such an extent by the heat taken up before
compression begins, that the volume of fresh air drawn in is much smaller than
would be the case if the combustion chamber were cooled, and consequently a larger
cylinder is required for a given power. Furthermore the heat radiated from this
large hot chamber is highly inconvenient when an engine is working in a con-
fined space.
The preliminary heating of the large combustion chamber also necessitates
the use of a very powerful heating lamp, with a proportionately large consumption
of oil or gas, the great heat of such a lamp or flame also is most inconvenient in
confined spaces.
In order to overcome these defects I employ an ignitin apparatus of such
capacity that only a relatively small proportion of the charge is compressed into
it and the consequent reduction in the area of the surface to be heated makes it
necessary that some other provision be made for imparting the required heat
besides that produced by the effect of the internal combustion, which alone would
be insufficient; and I therefore arrange the ignition tube so that it acts as a channel
or passage connecting the combustion chamber with the exhaust valve chamber,
both of which are water jacketted. The area of cross section of the igniting tube
must therefore be such as to allow sufficiently free escape of the exhaust gases..
The passage through the tube of the whole of the escaping highly heated pro-
ducts of combustion contributes largely to the necessary heating effect, notwith-
standing the smallness of the surface, and the fact that the ends of the tube are
connected by apertures of the full area with the water jacketted parts of the
cylinder.
but
The ignition tube may be made and arranged in any convenient manner,
I find it most convenient to make it in the form of a horseshoe bend; which permits
of free expansion of the tube when heated, and offers little resistance to the flow
of the escaping gases. It will be clear from the foregoing that my object is to
make my improved igniting tube as small and to maintain its temperature as
high, as possible, so as to secure approximately the results which are obtained by
the use of ordinary externally heated small ignition tubes.
The tube may be surrounded by a suitable casing containing the heating lamp,
or the arch formed by the horseshoe bend may be used so as to act as a flue or
chimney for the heating lamp, thus dispensing with a separate enclosing chamber.
In an oil engine my improved igniting, tube may be utilized for vapourising
the charge, or a separate vapouriser may be employed in any suitable known
manner.
When used as a vapouriser I fit the igniting tube with a branch pipe through

page_text: which the oil mixed with air is drawn, the said air being if desired, previously
heated by radiation from the igniting tube.
The main body of air is however drawn into the water jacketted combustion
chamber through an air inlet valve of the usual construction.
The oil vapour and air entering the combustion chamber from the vapouriser
are there mixed thoroughly with the main air charge during the drawing in stroke
of the piston; the mixed charge is compressed by the following stroke and a small
portion of it is forced into the igniting tube, which fires the charge at about the
point of maximum compression.
In the accompanying drawings Figs. 1, 2 and 3, the invention is shewn as
applied to an oil motor.
Fig. 1 is a sectional plan shewing the rear end, of the cylinder, Fig. 2 is a
vertical section on the line 2-2 of Fig. 1, Fig. 3 is a plan on the line 3-3 of Fig. 2.
A is the cylinder, B the piston, C the combustion chamber, D the exhaust valve,
E the main air inlet valve, F the horseshoe bend which at starting is heated by
a lamp, G the branch pipe, H the air inlet valve on same, I the oil supply jet,
supplied by the pipe L from a suitable pump and fitted with non-return valve J,
K is a water jacket which surrounds the cylinder, combustion space and main
air inlet and exhaust valve chambers.
CLAIMS.
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 motor in combination with the combustion
chamber and exhaust valve chamber, an external non-jacketted passage adapted
to form an igniting tube substantially as described.
2. In an internal combustion motor the arrangement and combination of a
combustion chamber and an exhaust valve chamber connected by a separate
external and non-jacketted passage adapted to act as a vapourising and igniting
chamber substantially as described for the purpose set forth.
3. In an internal combustion motor the arrangement and construction of a vapour-
ising and igniting apparatus substantially as described with reference to the
drawing.
Dated this 10th dar of Walma 1900