Improvements in Automatic Igniting Apparatus for Gas and Petroleum Motors.
Year: 1897

page_text: Date of Application, 25th Mar., 1897-Accepte, 1st May, 1897
COMI LEID DI PITIATION.
Improvements in Automatic Igniting Apparatus for Gas and
Petroleum Motors.
We, DONAT BANKI, of II Rorsahegy utca 6, and JOHANN CSONKA of
Szövetség uteza 5, both of Budapest, in the Kingdom of Hungary, Engineers, 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 :-
This invention consists in connecting an igniting tube Z by means of a thin tube z
with the combustion chamber R. By employing suitable dimensions for the igniting
tube and the connecting tube the igniting tube remains glowing without exterior
heating, but only by the heat derived from the explosions in the cylinder and the
lighting operated by this glowing tube is effected regularly near the dead point.
A tube z which has to be kept glowing by the explosion heat must be composed
of an appropriate material which receives heat well and must have a surface
receiving a great heat in proportion to the heat delivering surface; also the
igniting tube must possess a sufficient mass in order to receive and hold a
corresponding quantity of heat in itself. In order to correspond to all these
conditions there must be used a tube about 4 to 6 mm. thick (preferably of copper)
with a bore not less than 6 to 7 mm. A thin igniting tube, as used for ignition
in explosion motors with exterior heating, is cooled, as soon as the exterior lamp is
taken away and has therefore not the property of automatic ignition.
For more exact explanation of the process in the igniting tube we may imagine
a tube connected with the explosion chamber of a gas or petroleum motor, and,
that the motor is in operation that is to say in the cylinder explosions occur at
certain intervals. During the explosion stroke the temperature in the igniting
tube is very high and far surpasses the igniting temperature. In consequence of
the great difference of temperature a greater quantity of heat passes into the tube
walls and escapes again from the tube partly by radiation and by conduction.
After the explosion stroke has ended there remains in the tube walls a certain
amount of heat, which depends upon
1. The bore of the tube, that is to say, the inner tube surface, which receives
the heat,
2. The material of the tube, that is, the heat conducting property of the tube
material.
3. The thickness of the tube wall and,
4. The material surrounding the tube.
Referring to these points we remark as to the first generally a greater amount
of heat is introduced into the tube the larger its bore is; to the second the greater
the conducting property of the material, as much more heat will pass into the tube.
Copper, the conducting property of which is 0,7.3 with reference to silver, is much
more heated during the explosion than for instance iron, the heat conducting
property of which is only 0-12. On the third point we may remark that the
amount of heat disposable for heating the igniting tube during the explosion
period is the same as is contained in the combustion products enclosed in
the tube.
A thick walled tube will have a lower mean temperature while receiving the
same amount of heat as one with thin walls. However the thick tube will be able
of keeping the heat longer in consequence of its lower temperature.

page_text: To the, fourth point we may say that after the tube contains a certain quantity
of hot combustion products, which. serve for heating the tube, it is evident that
after the end the explosion stroke both the tube and the combustion products in
the tube are hotter if the tube is surrounded with a bad heat conducting cover
than when the exterior tube walls are exposed directly to the air.
It is thus clear, that a copper tube outwardly jacketted and with corresponding
dimensions remains glowing during the operation of the motor whilst a thin
uniusulated tube made of a less well conducting material for instance iron will
remain below the ignition temperature.
In our lighting tube composed of the two parts Z and the part Z has for the
above reasons a high ignition temperature whilst the tube piece z will never obtain
so high a temperature that is to say it can keep a lower temperature than is
necessary for ignition from the explosion period up to the moment of ignition.
The ignition is therefore effected by the tube Z and an ignition by the tube piece =
is excluded.
This property of this thin connecting tube z gives the explanation for the fact,
that by inserting this tube early ignitions are avoided.
When a combustible mixture escaping from the opening of a tube is ignited, this
mixture will continue burning at the tube opening, without the flame travelling
backwards into the tube so long as the velocity of the mixture does not sink under
a certain limit.
We can observe this process in any soldering lamp or Argand gas burner. The
same is intended with our igniting tube or combination of tubes.
The process in the tube from the beginning of the compression to the igniting
point is as follows:-
At the beginning of the compression the whole tube Z and is filled with
uncompressed combusted gases, but before the tube opening there is the combustible
mixture. On compression the combustible mixture penetrates first into the thinner
tube z and moves the expanded gases into the tube Z. In consequence of the
rising compression there would pass continually explosive mixture from the tube z
into tube Z which mixture is ignited by the hot walls of the tube Z and will
continue burning on the tube opening 2. Near the inner piston dead point the
piston velocity becomes less, the compression and the current through the tube
will therefore become weaker, until the flame moves finally through the tube z back
into the cylinder interior.
It is evident that this back movement of the flame which causes the ignition of
the main body of explosive mixture in the cylinder is brought nearer to the dead
point, the thinner the tube z is in proportion to the tube Z and that early ignitions
are less possible the longer this tube is and the more it is cooled.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed we declare that what we
claim is :-
Improvements in igniting devices for gas and petroleum engines in which a thin
tube arranged outside the cylinder connects the real automatic igniting tube with
the interior of the cylinder substantially as and for the purpose set forth.
Dated this 25th day of March 1897.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, London, Agents to Applicants.