Self-regulating heater

Abstract

A self-regulating electrically heated positive-temperature-coefficient (hereinafter PTC) carburetor stove for use in the fuel entry system of a gasoline engine is connected through the ignition system directly to the battery for rapidly heating of the stove upon starting of the car. This system comprises a plurality of PTC pills housed in a container with a high thermal conductivity top plate in direct heat transfer relation with the pills. Gasoline droplets are evaporated on this plate during cold start conditions to minimize the need to run a cold engine in the closed choke gasoline rich mode. During heat-up of the engine the PTC pills reach the anomaly temperature and at that point greatly increase their resistance thereby virtually terminating the power requirement of the stove in the heated engine mode.

What I claim is: 
     
       1. A fuel entry system of an internal combustion engine comprising a carburetor having one barrel through which fuel and air are adapted to pass, an intake manifold connected to said carburetor and having a wall at right angle to said barrel, a stove disposed in said wall and offset with respect to said barrel, said stove comprising a self-regulating heater element having a steeply sloped positive temperature coefficient of resistivity, means to electrically connect the element to power supply so that shortly after energization thereof the element is maintained at an essentially constant preselected temperature whereby fuel droplets coming in contact with the stove will be vaporized to enhance start-up of the internal combustion engine, said stove having a top plate in heat transfer relationship with said element, said top plate being provided with a multiplicity of heat-conducting rods on the side opposite to said element and projecting into said intake manifold, a baffle within said intake manifold for guiding the fuel-air stream passing through the barrel towards said stove, said baffle being mounted for rotation within said intake manifold, and means for rotating said baffle in dependence on engine load such that with increasing load said baffle is swung away from said stove. 
     
     
       2. The invention as claimed in claim 1, and further comprising an opening in said wall of the intake manifold, said stove being inserted into said opening with the surface of said top plate being flush with the inner surface of said wall. 
     
     
       3. The invention as claimed in claim 1, wherein said stove comprises a cup-shaped container with the bottom thereof forming said plate, the open end of said container lying outside said intake manifold and being closed by a terminal plate comprising terminals for connecting said heater to a power source and being of a heat-resistant, electrically insulating material. 
     
     
       4. The invention as claimed in claim 2, wherein said cup-shaped container has a lateral flange extending around the open end thereof and abutting the outer surface of said wall of the intake manifold. 
     
     
       5. The invention as claimed in claim 1, and further comprising passages in said wall, said passages being connectable to a water cooling circuit of the internal combustion engine. 
     
     
       6. The invention as claimed in claim 1 and further comprising means for switching off said element during starting of the engine. .Iadd. 
     
     
       7.  A fuel entry system of an internal combustion engine, comprising a carburetor having a barrel through which fuel and air are adapted to pass, an intake manifold connected to said barrel and having a bent configuration to provide a wall substantially at right angle and opposite to said barrel, a stove disposed in said wall and offset with respect to said barrel, said stove comprising at least one self-regulating heater element having a steeply sloped positive temperature coefficient of resistivity, means to electrically connect the element to a power supply so that shortly after energization thereof the element is maintained at a preselected temperature whereby fuel droplets coming in contact with the stove will be vaporized to enhance start-up of the engine, said stove having a top plate in heat transfer relationship with said element, said top plate having a surface which faces the interior of said intake manifold and is flush with the inner surface of said wall and is provided with a multiplicity of heat conducting rods projecting from said surface into said intake manifold. .Iaddend. .Iadd.8. A fuel entry system as claimed in claim 7 and further comprising a baffle within said intake manifold for guiding the fuel-air stream passing through the barrel 
     
     
        towards said stove. .Iaddend. .Iadd.9.  A fuel entry system as claimed in claim 8 wherein said baffle is mounted for rotation within said intake manifold, and further comprising means for rotating said baffle in dependence on engine load such that with increasing load said baffle is swung away from said stove. .Iaddend. .Iadd.10. A fuel entry system of an internal combustion engine, comprising a carburetor having a first barrel for low load operation and a second barrel for high load operation, an intake manifold connected to said barrels and having a bent configuration to provide a wall substantially at right angle and opposite to said barrels, said intake manifold continuing downstream of said second barrel in an intake pipe extending to an engine cylinder, a stove disposed in said wall substantially in alignment with said second barrel, said stove having a top plate with a surface flush with said wall and provided with a multiplicity of heat conducting rods projecting from said surface into said intake manifold, at least one self-regulating heater element in heat-transfer relationship with said top plate and having a steeply sloped positive temperature coefficient of resistivity, means to electrically connect the element to a power supply so that shortly after energization thereof the element is maintained at a preselected temperature whereby fuel droplets coming in contact with the top plate and rods will be vaporized to enhance start-up operation of the engine, and a baffle in said intake manifold extending from a spot between the barrels towards said rods so that the flow of fuel and air passing through the first barrel is forced to pass through the interstices between said rods. .Iaddend.