Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a fuel vaporizer for
the intake manifold of an.internal combustion engine equipped
with a downdraft carburektor.
It has previously been proposed to provide a fuel
: vaporizer for heating fuel discharged from a carburettor into
the intake manifold of an internal combustion engine, particularly
for use in cold climatic conditions.
. For example, United States Patent 2,597,251 teaches a
fuel vaporizer comprising a tube containing an insulated heating
-: 10- element and extending downwardly within a manifold intake from
a retaining frame or band sandwiched between gaskets between a
. carburettor flange and the manifold intake. The lower end of
~:i the tube is provided with a fuel trap consisting of a sleeve
.~ mounted on the tube and extending downwardly to a hQrizontal
plate having an annular upstanding peripheral flange and divided .
by a plurality of further flanges into pockets in which incoming ;
.. . fuel is trapped and vaporized by heat generated by the heating
''-J, element. .
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~;. This previously proposed vaporizer has the disadvantage .
: 20 that it provided inefficient utilization of.the electrical power
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:~ employed for energizing the heating element. To vaporize the
fuel trapped in the pockets, heat from the heating element must
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be transferred by condu~tion -through the sleeve exten~ing around
the lower end of the tube, and thence to the plate and flanges
forming the pockets, and since the plate and.fl~anges are of .
relatively thin metal, these parts cannot retain a large amount
` of heat.
The present invention is based on the concept that, in
order to avoid undesirably.high electricalpower consumption,
, 30 which would adversely affect the battery of the vehicle in which
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the vaporizer is provided and would cause tempera~ure control
problems, the vaporizer should include means by which heat from
. a low.power electrical resistance heater can be accumulated
over a period of time prior to starting of the engine.
It is accordingly an object of the present invention
to provide an improved fuel vaporizer which promotes efficient
.. starting of an internal combustion engine but which requires
;. less electrical power than prior art fuel vaporizers.
~ According to the present invention,there is provided
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. 10 a fuel vaporizer for the intake manifold of an internal com-
bustion engine, comprising a heat reservoir, a low power
, electrical resistance h~ater embedded in the heak reservoir,
j elongate support means for supporting the heat reservoir in
~ the intake manifold of the internal combustion engine, the heat
. reservoir comprising a block of a heat conductive material pro-
.~ jecting laterally from the support means, and the block having
~: an upwardly facing fuel impingement surface, and electrical ~: .
. current supply conductor means for supplying an electrical :
.. current to the electrical resistance heàter. ;
~ 20 Preferably, the vaporizer is urther provided with
`` switch means for connecting an electrical current supply source :.
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.. to the supply conductor means independently of the ignition
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.. i switch of the internal combustion engine,.and means responsive
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~ to starting of the internal combustion engine for interrupting
!'"~ the current suppl.y through the supply conductor~.means when the
.O internal combustion engine is started.
The invention will be more readily understood from
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the fol~owing description of the preferred .embodiment thereof
~.~ given, by way of example, with reference to the accompanying
.3
.~ 30 drawings, in ~hich~
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Figure 1 shows a partially broken-away view in per-
spective of a uel vaporizer arrangement embodying the present
invention and secured to a gasket positioned between a car-
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burettor and an intake manifold of an internal combustion engine;
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Figure 2 shows a view in perspective of one of the
fuel vaporizers of Figure 1 in greater detail;
~- Figure 3 shows a diagrammatic view in vertical section
I^! through the intake manifold, with the carburettor and gasket
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; secured thereto; and
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Figure 4 shows a circuit diagram of the fue1 vaporizer.
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Reerring firstly to Figure 1 of the accompanying
drawings, there is illustrated in this drawing an intake mani- I
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fold lO of an internal combustion engine provided with a car-
burettor, of which the bottom flange is indicated by reference
numeral 11.
A gasket 12 is shaped to fit between the top of the ¦ -
~ intake manifold 10 and the underside of the carburettor flange
; 11, these parts being secured together by securing screws in the
conventional manner.
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The gasket 12 has at its inner side two downwardly
,~ extending support tubes 14. More particularly, the upper end ¦
;~ of each support tube 14 extends horizontally into the gasket 12,
A" " in which it is supported. I;
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~ Each support tube 14 is shaped to extend vertically
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downwardly into the intake manifold 10 and is secured at its
lowermost end to a disc-shaped héat reservoir in the-form of a
block 15 of brass or other suitable heat conductive material.
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~;~ As can be seen more clearly from Figure 2,~the block
15 is formed at its upper side with a flat, upwardly facing fuel
impingement surface 17 surrounded by an upstanding, annular rim
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18 and provided with a plurality of fuel-containing recesses ~
19. ~':' ;'
. A cylindrical heater uni~ 16 is secursd at one ~:
." end to a cylindrical brass button 13, and the heater unit
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.. 16 and the brass button are f.itted into corresponding
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transverse borings in the block 15 and :retained therein
~,i by a grub screw 22 in threaded engagement with a further . ~:
' boring 23 in the block 15. The lower end of the support
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~. tube 14 is soldered to the brass button 13.
;' 10 AS can be seen from Figures 1, 2 and 3, the block ..
15 projects laterally Prom the vertical support pipe 14 into
.~/!, the path of the stream of liquid fuel, indicated by
`,~ reference numeral 20 in Figure 2, from the carburettor.
. Also, as can be seen from Figure 3, the suppork
.... j. tube 14 supports the block 15 slightly above the bottom
~ of the intake manifold flow passage beneath the carburettor, ~ ~
,`. so that the fuel vaporizer does not obstruct the airflow .:.
.~ indicated by arrows 21 in Figure 2.
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~: Figure 4 shows two heater elements 25 of respect-
:ive heater units 16. The heater elements 25 are connected, . :
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:~i by leads 24 extending through the support tubes 14, in
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parallel with one another between vehicle ground and one
contact of a normally-closed relay switch R, the other con-
.~ tact of which is connected, by conductor 26, through a
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~ manually-operable switch 27 to a vehicle battery (not shown). .
:~ An indicator lamp L connected between ground and :
the connector 26, i.e. in parallel with the heater elements
` ? 25, serves to provide a visual indication of closure of . ~.
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the manually-operable switch 27 and of the operation of the
relay R. :.
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The relay R comprises a coil 28 connected at one end
` to ground and at its opposite end, through a Zener diode 29, to
a conventional alternator 30.
~` The operation of the above-describ,ed apparatus is as
follows:-
Prior to starting of an engine in which the apparatus
is provided, the manually-operable switch 27 is closed to ener-
gize the heater elements 25. After a suitable period of time,
during which the block 15 is sufficiently heated by the heater
elements 25, the engine of the vehicle i5 ready to be started.
; The accelerator pedal of the vehicle is depressed
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several times in accordance with the vehicle manu~acturers in-
~, structions. The liquid fuel stream 20 from the carburettor
acceleration pump impinges on the block 15, and is vapourlzed.
The engine starter is then engaged and, after the engine has
started and is idling, the voltage of the alternator 30 reaches
a value sufficient to energize the coil 28 and to thereby open
~` the normally-closed contacts of the relay switch R. The lamp L
is de-energized, which indicates-that the relay switch R has
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~ 20 interrupted the current supply to the heater elements 25.
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