Fuel system having low profile gasket heater

A fuel system for an internal combustion engine has an electrical resistance heater accommodated in low profile gasket means at a location between a throttle body mounting flange and a mating intake manifold flange for heating the throttle body. The gasket means comprises a relatively rigid electrically insulating spacer forming a chamber, a heat-transfer member and a terminal secured to opposite sides of a heater for mounting and making electrical connection to the heater which is accommodated in the spacer chamber, and relatively thin outer layers of more compressible gasket material for sealingly engaging the throttle body and mating manifold flange means respectively.

BACKGROUND OF THE INVENTION 
The field of this invention is that of fuel systems for furnishing air or 
air-fuel mixtures to an internal combustion engine and the invention 
relates more particularly to means for preventing freeze-up of components 
in a throttle body means used in such a system. 
In fuel supply systems for internal combustion engines, air or a mixture of 
air and fuel is typically furnished to an engine through a throttle body 
means or the like mounted on the engines's intake manifold. The 
evaporation of fuel or the expansion of air and/or air-fuel mixtures and 
the like occurring in the throttle body means tends to produce a cooling 
effect which, under certain atmospheric conditions, can result in at least 
temporary freeze-up of throttle body components, such as, throttle 
bearings or idle speed fuel supply or inlet means or the like mounted on 
the throttle body means. As a result, there can be a failure of engine 
firing or a loss of suitable engine driveability. It would be desirable if 
heat could be furnished to such a throttle body means in a compact and 
efficient way promptly after initiation of engine operation to prevent 
such freeze-up. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a novel and improved fuel 
supply system; to provide such a system having means compactly and 
economically accommodated in the system for furnishing heat to the 
throttle body means of the system for preventing freeze-up of components 
of the throttle body means during operation of the system; and to provide 
such a system and a low profile heater for use in the system which is a 
rugged, reliable and economical structure. 
Briefly described, the novel and improved fuel supply system of this 
invention comprises throttle body means having passage means therein open 
at one end for communicating with a corresponding opening in an intake 
manifold of an internal combustion engine. The throttle body means is of 
any conventional type and can comprise a section of a carburetor, or a 
throttle body of a throttle body fuel injection system, or a throttle body 
or housing or the like of a direct port fuel injection system used for 
supplying air to an engine within the scope of this invention. In a 
typical application, for example, nozzle or slot means or the like are 
provided in the throttle body means at a selected location relative to the 
throttle body flange means for furnishing fuel to be evaporated within the 
throttle body means to form an air-fuel mixture to be furnished to the 
engine through the passage means when the engine is operated under idling 
conditions. Gasket means are provided between the throttle body flange 
means and the mating engine flange means and electrical resistance means 
are accommodated at a location between portions of the throttle body and 
engine flange means in a selected disposition within the gasket means 
relative to the nozzle or slot means to be energized within the gasket 
means to transfer heat to the throttle body flange means for preventing 
freeze-up of the nozzle or slot means or the like during furnishing of the 
fuel for forming the air-fuel mixture. The heater also serves to prevent 
freeze-ups in other applications where, for example, freeze-up of throttle 
bearings or idle fuel feeding means may be due to expansion of an air-fuel 
mixture in the throttle body means during regular running operation of the 
engine. 
In a preferred embodiment of this invention, the gasket heater means has a 
low profile to be compactly accommodated between the throttle body flange 
means and the mating engine flange means, the gasket heater means 
preferably comprising a first spacer layer member of a relatively rigid 
electrically and thermally insulating material such as a phenolic material 
or the like of selected thickness. The spacer member has a first opening 
forming a chamber in the spacer and has a second opening which is aligned 
between the throttle body passage means and the intake manifold opening. A 
second heat-transfer layer member formed of a thermally and electrically 
conductive material such as aluminum or the like having an opening therein 
aligned with the passage means has one side secured in overlying 
substantially coextensive and preferably in sealing, relation to one side 
of the spacer member to extend over the spacer chamber. An electrically 
conductive terminal member is embedded in the spacer member, preferably 
flush with an outer surface of an opposite side of the spacer member, so 
that the terminal means extends into the spacer chamber and preferably 
seals the chamber. A self-regulating electrical resistance heater of a 
ceramic material or the like of positive temperature coefficient of 
resistivity has one side secured in thermally and electrically conductive 
relation to said one side of the heat-transfer member so that the heater 
is accommodated within and sealed in protected relation within the spacer 
chamber by the relatively rigid spacer material. Spring means are also 
accommodated in the chamber for electrically connecting an opposite side 
of the heater to said terminal means. Third and fourth gasket layer 
members of a relatively thin and compressible electrically insulating 
gasket material such as an asbestos-filled nitrile compound or the like 
have respective openings therein aligned with the throttle body passage 
means, the third and fourth members being secured in substantially 
coextensive, overlying relation to an opposite side of the heat-transfer 
member and to said opposite side of the spacer respectively in sealing 
engagement with respective throttle body flange means and the mating 
engine flange means. In a preferred embodiment, the noted terminal means 
has an end extending therefrom beyond a lateral edge of the spacer member 
for connecting one side of the heater in an electrical circuit. The third 
gasket layer member also preferably has an additional opening therein and 
additional resilient spring means are secured in electrically conductive 
relation to the heat-transfer member to extend through said additional 
opening to electrically engage the throttle body flange means for 
connecting the other side of the heater in the electrical circuit. 
In that arrangement, the heater is adapted to be energized promptly on 
initiation of operation of the engine to avoid freeze-up of the nozzle or 
slot means or the like provided in the throttle body means as fuel 
evaporation or expansion or the like occurs in the passage means. The 
gasket heater means is compact, reliable and inexpensive and is adapted to 
be easily and reliably accommodated between the throttle body means and 
the engine for providing improved engine operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings, 10 in FIG. 1 indicates the novel and improved 
gasket heater means of this invention which is shown in FIG. 2 to be 
incorporated in the novel and improved throttle of the fuel supply system 
12 of this invention. The system 12 includes a throttle body means 14 
having passage means 16 open at one end 16.1 to communicate with a 
corresponding opening 18 at an intake manifold of an internal combustion 
engine diagrammatically indicated at 20 in FIG. 2. The throttle body means 
has flange means 22 arranged around the open passage end 16.1 for 
cooperating with corresponding or mating flange means 24 on the intake 
manifold and the gasket heater means 10 is arranged between the noted 
flange means for sealing communication between the passage means 16 and 
the intake manifold opening. Preferably screw means (not shown) are 
extended through mounting holes 27 provided in the gasket means 10 and 
through corresponding mounting holes (not shown) in the throttle body 
flange means 22 and mating flange means 24 for mounting the throttle body 
on the engine in a conventional manner. The throttle body means is of any 
conventional type and can comprise a section of a carburetor, or a 
throttle body of a throttle body fuel injection system, or a throttle body 
or housing or the like of a direct port fuel injection system used for 
supplying air to an engine within the scope of this invention. 
In the usual application of this invention, the throttle body means 
incorporates components, such as, throttle bearings or idle screw means or 
the like which could be subject to freeze-up during engine operation. 
Typically for example, such throttle body components comprise idle screw 
or nozzle means 26 of any conventional type which are provided in the 
throttle body means to open into the passage means 16 for furnishing fuel 
into the passage, as is diagrammatically indicated at 28 in FIG. 2, 
thereby to form an air-fuel mixture in the throttle body means and to 
furnish that mixture to the engine as is indicated in FIG. 2 by the arrows 
30 for regulating idling operation of the engine in conventional manner. 
Throttle valve means 32 are movably mounted in the passage means for 
regulating the flow of the air-fuel mixture to the engine in conventional 
manner. Typically, for example, the nozzle means 26 comprises a needle or 
valve member 26.1 threadedly engaged in the throttle body means as 
diagrammatically indicated at 26.2 in FIG. 2 so that a valve end 26.3 of 
the member is movable in a fuel entry slot, hole or passage 26.4 toward 
and away from a valve seat 26.5 formed in the fuel entry passage when head 
means or other valve control means 26.6 or the like are rotated as is 
indicated by arrow 26.7. In that arrangement, movement of the valve member 
toward and away from the valve seat 26.5 regulates the entry of a stream 
of fuel 28 into the passage 16 in response to engine vacuum or the like 
when the engine is idling so that the fuel rapidly evaporates in the 
passage to form the air-fuel mixture 30. As the nozzle means 26 is of any 
conventional type in accordance with this invention, it is not further 
described herein and it will be understood that the nozzle means supplies 
a fine regulated stream of fuel into the passage means 16 to be evaporated 
in the passage and that cooling which results from such fuel evaporation 
or from the expansion or evaporation of other air or air-fuel mixtures in 
the throttle body could tend to cause at least temporary or intermittent 
freeze-up of the nozzle means 26 resulting in occasional failure of engine 
firing or loss of engine driveability under at least some atmospheric 
conditions. 
In accordance with this invention, the novel and improved gasket heater 
means 10 are arranged between the throttle body flange means 22 and the 
mating engine flange 24 so that electrical resistance heater means 
accommodated in the gasket means are located between portions of the 
throttle body flange means and the mating engine flange means at a 
selected location relative to the nozzle means 26 or the like in the 
throttle body means for transferring heat to the throttle body flange 
means for heating the throttle body to prevent such freeze-up of the 
nozzle means or the like. 
In a preferred embodiment of the invention, gasket means 10 comprises a 
first spacer layer member 34 formed of a relatively rigid, thermally and 
electrically insulating phenolic material or the like. The spacer member 
has a first opening which forms a chamber 36 in the spacer and has a 
second, typically larger opening 38 which is aligned with the passage 
means 16 and with the intake manifold opening 18 as shown in FIG. 2. The 
spacer member has a selected thickness providing the chamber 36 with a 
selected capacity as discussed below. A second heat-transfer layer member 
40, preferably formed of a metal material such as aluminum or the like of 
relatively high thermal and electrical conductivity has a corresponding 
opening 42 also aligned with the passage 16. The heat-transfer member has 
one side 40.1 which is secured in substantially coextensive, overlying 
relation to one side 34.1 of the spacer member. The heat-transfer member 
extends over the chamber 36 and is preferably sealed to the spacer 34 by 
an adhesive (not shown) or by fusing of the spacer material or the like 
for sealing one end of the chamber 36. An electrically conductive metal 
terminal means 44 is embedded in the heater means 10 to extend into the 
opposite end of the chamber 36. An electrically conductive metal terminal 
means 44 is embedded in the heater means 10 to extend into the opposite 
end of the chanber 36. Preferably, for example, the terminal means 
comprises an element of aluminum or copper or the like which is embeded in 
a slot 34.2 in the spacer 34 so that one end 44.1 of the terminal extends 
into the chamber to cover said opposite end of the chamber, so that an 
opposite end 44.2 of the terminal extends out from a lateral edge of the 
spacer 34 for electrically connecting the terminal in an electrical 
circuit, and so that the terminal fits in the slot 34.2 to be 
substantially flush with an outer surface 34.3 of the spacer, the slot 
preferably accommodating the terminal therein just slightly below the 
surface 34.3 to avoid interference problems in subsequent assembly steps. 
Preferably the terminal is secured to the spacer by adhesive means or 
fusing of the spacer or the like so that the terminal 44 seals the 
opposite end of the chamber. 
In accordance with this invention, a self-regulating electrical resistance 
heater means 46 is accommodated in the chamber 36 to be energized therein 
for transferring heat to the throttle body flange means 22 through the 
heat-transfer member 40. Preferably for example, the heater means 
comprises a heater unit having a body 46.1 of a ceramic material or the 
like such as lanthanum-doped barium titanate having a positive temperature 
coefficient of resistivity adapted to display a sharply anomalous increase 
in resistance at a selective, safe temperature level for stabilizing the 
heater at about that temperature. Ohmic contact layer 46.2, 46.3 of metal 
such as aluminum or the like are provided on opposite sides of the body 
46.1 and one contact layer 46.2 at one side of the body is secured in 
electrically and thermally conducted relation to the heat-transfer member 
40 so that the heater is accommodated in the chamber 36. Preferably for 
example, the heater body is secured to the member 40 by use of an 
electrically and thermally conductive, metal-filled epoxy adhesive 46.4 or 
the like as shown in FIG. 2. Electrically conductive spring means 48 such 
as a spider spring formed of berrylium copper or the like are also 
accommodated in the chamber 36 between the opposite side of the heater 
body and the terminal 44 for electrically connecting the terminal to the 
heater. 
In accordance with this invention, third and fourth gasket layer members 50 
and 52 each having an opening 54, 56 therein aligned with the passage 16 
are disposed on opposite outer sides of the gasket means 10 to sealingly 
engage the throttle body flange means 22 and the intake manifold flange 24 
respectively. The third and fourth layer members are preferably relatively 
thinner and of relatively more compressible electrically insulating 
material than the spacer 34 and are preferably secured by fusing or 
adhesive means or the like at opposite sides of the gasket means 10 so 
that one gasket layer member 50 is disposed in substantially coextensive, 
overlying relation to the heat-transfer member 40 and the other gasket 
member 52 overlies and is coextensive with the opposite side 34.3 of the 
spacer without interference with the terminal 44 accommodated in the slot 
34.2. Typically for example, an asbestos-filled nitrile gasket material is 
used but other compressible materials with or without other fillers are 
also used within the scope of this invention. In a preferred embodiment of 
the invention, the gasket layer 50 has an additional terminal opening 50.1 
therein (see FIG. 1) and additional resilient terminal spring means such 
as a plurality of leaves 58 are secured to the side 40.2 of the 
heat-transfer member 40 at one end 58.1 so that opposite ends 58.2 of the 
springs extend through the opening 50.1 to electrically engage the 
throttle body flange or intake manifold 22 and 24 thereby to connect the 
side 46.2 of the heater body to the throttle body flange in the noted 
electrical circuit as will be understood. 
In that arrangement, the end 44.2 of the terminal means embedded in the 
spacer is adapted to be electrically connected to an automotive power 
source such as the battery 58 through switch means or the like such as the 
ignition switch 60 diagrammatically illustrated in FIG. 1. The heater 
means 46 is thereby connected in an electrical circuit between the 
terminal 44 and the throttle body 14, as is diagrammatically indicated in 
FIG. 1. Accordingly, the heater means is promptly energized when the 
switch 48 is closed for promptly generating heat and transferring that 
heat to the throttle body flange means 22 through the heat-transfer member 
40 in an efficient manner. In that way, the throttle body means receives 
heat for preventing freeze-up of the nozzle means 26 or other components 
of the throttle body. The heater means is also self-regulating to 
stabilize at a safe temperature. The novel and improved gasket means 10 
has a very low profile and is compactly accommodated between the flange 
means 22 and 24 and is readily connected in an electrical circuit. The 
heater means is safely and reliably accommodated within chamber 36 in the 
relatively rigid spacer 34 so it is protected during use when clamped 
between the flanges 22 and 24 and is preferably sealed therein for long 
service life. If desired, a thermostat means 62 as diagrammatically 
illustrated in FIG. 1 is also accommodated in a corresponding chamber in 
the rigid spacer 34 or the like, preferably adjacent to the nozzle means 
26 or the like to be responsive to throttle body temperature to open the 
noted circuit on warm days or the like for energizing the heater means 46 
only when said temperature is below a selected ambient or other 
temperature level. 
It should be understood that although particular embodiments of the gasket 
heater means and fuel supply system of this invention have been described 
by way of illustrating the invention, this invention includes all 
modifications and equivalents of the disclosed embodiments falling within 
the scope of the appended claims.