Fuel Supply System With Improved Throttle Body Heater

The field of this invention is that of fuel supply systems for internal combustion engines and the invention relates more particularly to a fuel supply system having electrical heater means arranged to prevent freeze-up of throttle body means or the like in the system, particularly as fuel is evaporated in the system to be furnished to the engine in an air-fuel mixture.

When air or an air-fuel mixture is furnished to an internal combustion engine through throttle body means in a carbureted fuel supply system, in a throttle body injection system, or in a direct port fuel injection system or the like where the throttle body controls the amount of air available to the engine or the like, there is a tendency for some components of the system, particularly components such as the throttle bearings or the like of the throttle body means, to freeze-up and operate poorly or to fail to operate under some atmospheric or driving conditions. Such freeze-up tends to occur particularly as operation of an internal combustion engine is initiated. It would be desirable if heat could be provided to the fuel system as soon as engine operation is initiated to counteract this tendency of freeze-up to occur in the throttle body means.

It is an object of the invention to provide a novel and improved fuel supply system having means for avoiding freeze-up of throttle body means in the system; to provide such a system having gasket means accommodating electrical resistance heater means therein to be located between mounting flange means on the throttle body means and mating flange means on the engine for transferring heat to the throttle body means through the flange means; to provide a novel and improved gasket heater means for use in such a system; and to provide such a novel and improved fuel supply system and gasket heater means which is a rugged, reliable and economical construction.

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 the engine for furnishing air or an air-fuel mixture to the engine. The throttle body means 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 within the scope of this invention. The throttle body means has flange means which are disposed around the open end of the throttle body passage means to mate to corresponding flange means provided on the intake manifold of the engine around the intake manifold opening. Preferably the flange means serve for mounting the throttle body means on the engine. Gasket means are provided between the throttle body flange means and the mating engine flange means and, in accordance with this invention, a chamber is provided in the gasket means at a location between portions of the two noted flange means. The gasket means provide selected spacing between the flanges and have compressible sealing means at respective opposite sides of the gasket means for sealingly engaging the respective throttle body flange means and mating engine flange means for sealing communication between the throttle body passage and the intake manifold opening. An electrical resistance heater means is accommodated in the chamber between portions of the throttle body flange and the mating engine flange to be energized therein, preferably on initiation of engine operation, for transferring heat to the throttle body flange means to avoid freeze-up of a throttle body means.

In a preferred embodiment of the invention, an aperture is provided in the gasket means communicating with one side of the chamber. A cup-shaped metal heat-transfer element having a bottom, a side wall and a rim and having a flange on the rim is located within the chamber so that the bottom of the element is adapted to move to extend out of the chamber through the aperture to engage the throttle body flange means. A self-regulating electrical resistance heater element of a material of positive temperature coefficient of resistivity has one side thereof bonded in thermally and electrically conductive relation to the bottom of the cup-shaped heat-transfer element inside the element; a metal terminal means is disposed on the gasket means at an opposite side of the chamber; and spring means are disposed between the terminal means and the opposite side of the heater unit for electrically connecting the heater unit to the terminal means and for biasing the heat-transfer element into engagement with the throttle body flange means for electrically grounding the heater unit to the throttle body means and connecting the electrical heater means in an energizing electrical circuit.

Other objects, advantages and details of the novel and improved fuel supply system and gasket heater means of this invention appear in the following detailed description of preferred embodiments of the invention, the detailed description referring to the drawings in which:

FIG. 1 is a partial side elevation view of a fuel supply system of this invention; and

FIG. 2 is a partial section view to enlarged scale along the vertical axis of the system of FIG. 1.

Referring to the drawings, 10 in FIGS. 1 and 2 indicates the novel and improved fuel supply system of this invention which is shown to include a throttle body 12 having throttle body components such as the throttle valve 14 mounted therein. The throttle body means 12 has throttle body flange means 16 arranged to mate with corresponding flange means 18 on the intake manifold 20.1 of an internal combustion engine diagrammatically illustrated at 20 in FIGS. 1 and 2. Preferably the flange means 16 and 18 serve for mounting the throttle body means on the engine as is diagrammatically illustrated in FIGS. 1 and 2 by the bolt means 21. The throttle body means 12 has passage means 22 therein which open at one end 22.1 for communicating with a corresponding opening 20.2 in the intake manifold for furnishing air or a mixture of air and fuel to the engine in conventional manner as is diagrammatically illustrated by the arrows 24 in FIGS. 1 and 2. Typically the throttle valve 14 is rotatably movable in bearings 26 in the throttle body means as is diagrammatically indicated by arrows 28 in FIGS. 1 and 2 so that the throttle valve blade 14.1 regulates the flow of air or air-fuel mixture 24 to the engine in the throttle body passage 22. In such a throttle body arrangement, it will be understood that there is a tendency for the throttle body bearings to freeze-up when air or an air-fuel mixture is furnished to the engine through the throttle body passage 22. This is particularly true when fuel is evaporating in the passage during engine start-up on the occurrence of selected atmospheric conditions or the like.

In accordance with this invention, novel and improved gasket heater means 30 are arranged between the throttle body flange means 16 and the mating flange means 18 on the engine for sealing communication between the passage 22 and the intake manifold opening 20.2 and for transferring heat to the throttle body means 12 for preventing freeze-up of throttle body components during furnishing of air or an air-fuel mixture to the engine 20. In a preferred embodiment of this invention, for example, the novel and improved gasket means 30 comprises a compressible gasket means 32 of a material such as a phenolic resin or the like, preferably having multiple layers 32.1, 32.2 and 32.3 or the like secured together by adhesive means (not shown) or by fusing or the like. The gasket means are adapted to provide a selected spacing between the flanges 16 and 18 when the bolts 21 are drawn down to apply selected pressure on the gasket means and opposite sides 32.4, 32.5 of the compressible gasket material are adapted to sealingly engage the respective flanges 16 and 18. Chamber means 34 are provided in the gasket means at a location within the gasket means such that when the gasket means 30 is arranged between the flanges 16 and 18 at least part of the chamber means is disposed between the mating flanges 16 and 18. Typically for example, a pair of the chambers 34 (only one of which is shown in FIG. 2) are provided in the gasket means at locations beneath the throttle body flange means 16 aligned with the respective locations of the bearings 26 in the throttle body for a purpose to be described below. Preferably as shown in FIG. 2, the gasket means has an aperture 36 communicating with each chamber 34 at the side of the chamber adjacent to the throttle body flange means 16.

In accordance with this invention and electrical resistance heater 38 is accommodated within the gasket chamber means 34 to be energized therein for transferring heat to the throttle body means 12 as described below. Preferably for example, a metal heat-transfer means 40 is arranged at one side of the heater means for facilitating heat-transfer to the throttle body flange 16. Preferably also, metal terminal means 42 are arranged in the gasket means at an opposite side of the heater means and conductive metal spring means 44 are disposed between the terminal means and the heater means for electrically connecting the terminal means to the heater means. Preferably the terminal means 42 comprises a support portion 42.1 embedded in the gasket means and a terminal post portion 42.2 which extends from the gasket means through a slot 42.3 in the gasket means.

In a preferred embodiment of the invention, the metal heat-transfer means 40 comprises a cup-shaped metal element having a bottom 40.1, a side wall 40.2, a rim 40.3, and a flange 40.4 extending around the rim. Projections 40.5 are preferably provided on the outer side of the bottom of the element. The heater means 38 preferably comprises a self-regulating electrical resistance heater unit having a body 38.1 of a ceramic material or the like such as lanthanum-doped barium titanate of positive temperature coefficient of resistivity having metal contact layers 38.2 and 38.3 formed on opposite sides thereof. Preferably the heater body material is selected to display a sharp anomalous increase in resistivity when electrically energized for stabilizing at a safe element temperature after energization. The contact layer 38.3 on one side of the heater unit is bonded in thermally and electrically conductive relation to the heat-transfer cup by use of an electrically conductive, metal-filled epoxy adhesive 45 or the like. The spring means 44 typically comprises a coil spring means as shown or a corresponding cantilever or bifurcated leaf spring or the like which is disposed between the terminal means and the opposite contact layer 38.2 of the heater unit for electrically connecting the heater unit to the terminal means and for biasing the heat-transfer cup to extend from the aperture 36. The heat-transfer cup is arranged to be movable in the chamber 34 to extend its bottom through the aperture 36 to electrically engage the throttle body flange means 16 as shown in FIG. 2. The flange 40.4 of the heat-transfer cup is arranged to engage a portion 34.6 of the gasket layer 34.1 for limiting extension of the heat-transfer cup from the aperture 36.

In that arrangement, the terminal post 42.2 of the gasket heater means 30 is adapted to be electrically connected to an automotive power source such as the battery 46 through switch means or the like such as the ignition switch 48 and the throttle body means 12 is connected to electrical ground for connecting the heater unit 38 in an electrical circuit as is diagrammatically illustrated in FIG. 1. The heater unit 38 is connected in the electrical circuit between the terminal means 42 and the throttle body flange 16. Accordingly, the heater unit is promptly energized when the ignition switch 48 is closed for promptly generating heat and transferring that heat to the throttle body flange means 12 in an efficient manner. In that way the throttle body means receives heat for preventing freeze-up of throttle body components such as the throttle bearings 26. The heater unit is self-regulating so that it stabilizes at a safe temperature for continuing its desired throttle body heating effect. The gasket means 30 is easily and economically manufactured and is easily and compactly accommodated in the fuel supply system 10 in conventional manner.

It should be understood that although particular embodiments of the 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.