Patent Publication Number: US-3875917-A

Title: Thermo-jet carburetor

Description:
United States Patent Scarritt, Sr. Apr. 8, 1975 1 THERMO-JET CARBURETOR 3.210.055 10/1965 Kinglcy 26l/39 B 36. I4 8 7 k 1 1 26144 R [761 lnvenm&#34; Frank Scam 1338 Park 3253 6 42 4x332 261544 R St., N., Saint Petersbur Fla. 33710 1 g FOREIGN PATENTS OR APPLICATIONS {22] 1973 1.224.162 3/1971 United Kingdom 261/44 R [2|] Appl. No.: 330.390  
  Primary Examiner-Charles J. Myhrc 52 us. c1 123/119 R; 123/119 F; 261/39 B; Asssmm Lazarus [5 [1 Int Cl F52 rh 770 [57] ABSTRACT [58] Fieid A, 39 B; The air-fuel ratio of a throttle controlled carburetor is I23 19 F. l 9 R regulated as a function of the speed, load and temperature of an engine as well as throttle valve position, by [56] Reierences Cited the joint control of vacuum and temperature responsive devices over a fuel metering device. A thermostat UNITED STATES PATENTS senses only the temperature of the coolant in the enfi&#39; (M915 f&#39; F gine cooling system to regulate flow of vaporized fuel (M931 Skmner 4 4 R through the fuel metering device into the mixing 2.702.536 2/!955 Carlson 1 261/39 B chamber of the carburetor 3.120.841 2/1964 B01101 123/119 F 3,198.185 8/1965 Nustas 123/119 F 8 Claims, 3 Drawing Figures HOT WATER W 1 m FUEL IN 26 i ll 24 I08 1 104 3 16 122 &#39;00 l as 44 6 22 n 76 1 11a 1211 9o 150 l 2 11 1211 l 2 11 94 11s an m 5a m 152 m iii-39 5. 3 x, 52 as HOT WATER OUT T0 ENGINE AIR IN HOT WATER IN PATENIEDAPR 81975 FUEL IN SHEET 2 [IF 2 TO ENGINE HOT WATER OUT THERMO-JET CARBURETOR This invention relates to control over the flow rate and air-fuel ratio of fuel mixtures to internal combustion engines for the purpose of improving combustion efficiency so as to reduce pollution resulting from engine exhaust.  
 BACKGROUND OF THE INVENTION One of the current approaches being taken to reducing air pollution resulting from automotive engine exhausts, is to improve combustion efficiency by special carburetor modifications. Generally. such modifications are expensive and require frequent maintenance to remain effective. Often such modifications will improve combustion efficiency under certain conditions at a sacrifice to operational efficiency under other conditions. For example, improving carburetor performance under normal engine running conditions is not compatable with optimum cold engine starting or accelerating conditions. Thus, there has been a proliferation of complicating modification proposals involving accelerating jets and pumps associated with automotive carburetors in an effort to overcome the compromises of carburetor design that account for incomplete combustion under certain conditions.  
  It is therefore an important object of the present invention to provide a carburetor which will supply a fuel mixture to the engine at a regulated airfuel ratio for more complete burning of the fuel within the engine under different operating conditions, this objective being achieved by a relatively simple and easily serviced arrangement.  
  An additional object of the invention is to provide a carburetor, in accordance with the foregoing object, that has no fixed fuel accelerating jets or pumps and which also performs with less fuel percolation under hot engine starting or accelerating conditions.  
  Yet another object of this invention is to provide a carburetor that has a thermostatically controlled, air to fuel ratio.  
 SUMMARY OF THE INVENTION In accordance with the present invention, a carburetor having a throttle valve located downstream of a venturi throat passage within which air and vaporized gasoline are mixed, has its air inflow rate varied as a function of engine vacuum by means of a pressure responsive piston biased to a position substantially blocking inflow of air to the throat passage. A tapered, flow restricting control element connected to and movable with the piston extends into the flow passage of a fuel metering device positioned within the fuel bowl from which vaporized gasoline is injected into the carburetor under the vacuum created by flow of air through the carburetor. The fuel metering device is also automatically displaceable relative to the flow control element against the opposing bias of a spring to modify the fuel inflow rate as a function of engine temperature. Toward that end, flow of water or engine coolant through the engine cooling system is diverted through a chamber within which a temperature sensing thermostat is located for sensing engine temperature independently of other variables such as pressure and temperature of the liquid fuel or the air. The thermostat is connected to an actuating stem engageable with the fuel metering device for making the fuel mixture more lean as engine temperature rises.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified side elevational view illustrating a typical installation for the present invention.  
  FIG. 2 is a vertical side section view through a carburetor constructed in accordance with the present invention.  
  FIG. 3 is a partial section view taken substantially through a plane indicated by section line 33 in FIG. 2.  
 DETAILED DESCRIPTION OF A SPECIFIC EMBODIMENT Referring now to the drawing in detail, FIG. I illustrates a typical power plant installation generally denoted by reference numeral 10 involving an internal combustion engine 12 having a cooling system which includes a surrounding engine water jacket and a radiator 14 through which heat is removed. Fuel such as vaporized gasoline is supplied to and mixed with air within a carburetor generally referred to by reference numeral 16 of a downdraft type as shown. the air being drawn into the carburetor through an air cleaner 18 under the vacuum pressure generated by operation of the engine to which the fuel mixture is conducted by an intake manifold 20 to which the carburetor is con nected.  
  Associated with the carburetor 16 is a thermostat unit 22 through which a flow of coolant is conducted, diverted from the engine cooling system. Although. coolant flow is shown diverted from the downstream side of the radiator 14 is FIG. I by way of example. it should be appreciated that coolant flow may be diverted from its upstream side or from other locations along the coolant flow path in the cooling system dependent on engine operating temperatures and the sensitivity of the thermostat unit 22. The thermostat unit is thereby able to regulate operation of the carburetor in accordance with engine temperature as will be explained in detail hereafter.  
  Referring now to FIGS. 2 and 3, the carburetor 16 includes a housing body 24 having an air intake conduit portion 26 on the upstream side of a venturi throat passage or space 28 formed within an intermediate body portion 30. A fuel mixture conduit portion 32 is connected to the body portion 30 of the carburetor on the downstream side and is connected to the intake manifold 20 of the engine. The usual throttle valve 34 is rotatably mounted within the conduit portion 32 and is adapted to be angularly displaced from the closed throttle position shown, clockwise to an open throttle position by an accelerator pedal linkage (not shown). Upon opening of the throttle valve during engine operation. vacuum pressure generated within the engine combustion chambers will draw in air through the air intake conduit portion 26 for mixing with fuel introduced into the throat passage 28 as is well known in the art.  
  The vacuum pressure is applied to a vacuum responsive device generally denoted by reference numeral 36 in FIG. 2 through a passage 38 inits tubular housing 40 which extends laterally from one side of the carburetor body 24. The housing 40 encloses a cylindrical chamber that is sealed at one axial end by an end cover 42 secured to a flange 44 by fasteners 46 with a sealing gasket 48 clamped between the flange and cover. A tubular air flow regulating piston element 50 is slidably mounted in the housing chamber having its open axial end 52 projecting into the carburetor body 24 to control inflow of air from conduit portion 26 to the throat passage or fuel mixing space 28. The piston is biased to an airflow blocking position as shown by a spring 54 bearing against the end wall 56 of the piston at one axial end. The other axial end of the spring is seated in a retainer 58 that is adjustably positioned in the housing 40 by a spring bias adjusting screw 60 threadedly mounted in the housing cover 42. The end wall 56 of the piston is exposed on one axial side to the static pressure of the air in communication with the interior of the piston through port 62 in the flow blocking position of the piston. The other axial side of the piston end wall 56 within the pressure sealed chamber of housing 40 is exposed to throttle controlled, engine vacuum through passage 38 which is in fluid communication with the conduit portion 32 of the carburetor. Thus, increasing vacuum in the housing chamber upon opening of the throttle valve 34 will cause displacement of the piston 50 against the bias of spring 54 to increase the inflow rate of air and the flow rate of the fuel mixture to the engine intake manifold. The rate of supply of fuel mixture to the engine will therefore be a function of engine speed and load as well as fuel demand or throttle valve position.  
  The vacuum responsive device 36 will also regulate the air-fuel ratio through a fuel metering device generally denoted by reference numeral 64 that is associated with a fuel storing float bowl 66 as shown in FIG. 2 to which a a liquid fuel such as goasoline 68 is supplied from a suitable source through fuel line 70. The liquid fuel is maintained at a predetermined level 72 within the bowl by a conventional float control mechanism 74 shown in FIG. 3 by dotted line, of well known construction and operation coarried by bowl cover 75. The fuel metering device includes a tubular housing 76 connected to and extending laterally from the carburetor body 24 opposite the housing 40 ofthe vacuum responsive device 36 and in axial alignment therewith. The housing 76 is also interconnected by a conical flange 78 to an end wall 80 of the fuel bowl 66 opposite the wall formed by the carburetor body in the illustrated em bodiment. The housing 76 slidably mounts a fuel injection member 82 through which vaporized gasoline is introduced into the mixing space 28 of the carburetor. The member 82 includes a hollow sealing portion 84 provided with external grooves seating O-ring seals 86 in wiping contact with the internal cylindrical surface of the housing 76 to separate the mixing space in the carburetor from the fuel storing space of the fuel bowl 66. A diametrically smaller fuel metering sleeve 88 extends from the sealing portion 84 of the member 82 into the mixing space of the carburetor and is provided with a fuel metering bore or passage 90 spaced just above the level 72 of the liquid fuel. For example, the spacing in a working model has been found satisfactory at one thirty-second of an inch. Accordingly, fuel vapors will be drawn into the mixing space through the fuel passage 90 at a flow rate regulated by a flow restriction member inthe form of a tapered pin 92 projecting into the passage 90 from its open discharge end 94 within the mixing space 28 of the carburetor. The Pin 92 is connected by its threaded end portion 96 to the end wall 56 of the vacuum responsive piston 50 and extends coaxially therefrom through opening 98 in the body portion 30 of the carburetor, across the mixng space into the fuel flow passage 90. In view of the taper of the pin 92, the degree to which it will restrict flow through the constant diameter passage will depend on the relative axial positions of the fuel injection member 82 and the pin 92 or piston 50. A spring 100 seated within the housing 76 and bearing against the sealing portion 84 of the member 82 biases it to a limit position tending to increase the flow rate of vaporized fuel through passage 90 to provide a richer fuel mixture for starting or accelerating conditions. Displacement of the flow restricting pin 92 by the piston 50 under the bias of spring 54 in response to a decrease in vacuum, will on the other hand tend to decrease the flow rate of fuel through passage 90 to make the fuel mixture more lean. Thus, the fuel flow rate will be regulated under the joint control of the vacuum responsive device 36 and the temperature sensing unit 22 which is operative to displace member 82 from its limit position shown in FIGS. 2 and 3. The fuel discharged from the end 94 of the sleeve 88 expands into the cross-sectionally V-shaped mixing space 28 as shown in FIG. 3 which constitutes the venturi throat passage of the carburetor as aforementioned.  
  The temperature sensing unit 22 includes a coolant chamber housing 102 connected by the spacers 104 to the end wall 80 of the fuel bowl and fuel metering device 64. Engine coolant from the radiator 14, for example, is diverted to the chamber housing 102 by conduit 106 connected to the housing by inlet fitting 108 and returned to the engine cooling system by conduit 110 connected to the housing by outlet fitting 112. A thermostat 114 of well known construction and operation is mounted within the housing 102 and connected to an actuating stern 116 which slidably extends through packing seal assemblies 118 and 120 respecetively mounted on the end wall 122 of housing 102 and end wall 80 at the fuel metering device 64. The end portion 124 of the actuating stem bears against a ported end wall 126 of the member 82 so as to displace the same against the bias of spring 100 in response to a rise in temperature of the coolant as sensed by the thermostat 114. Both axial limit positions of the actuating stem are determined by nuts 128 and 130, engageable with confronting stop surfaces on the stop members 132 and 134 secured to the end walls 122 and 80. The nuts 128 and are adjustably positioned on the actuating stem along its threaded portion 136 axially located between the packing assemblies 118 and 120. Thus, by adjusting the position of nuts 128 and 130, displacement of the member 82 is limited to obtain the desired range of fuel inflow variation under control of the temperature sensing unit 22. To adjust the effect of the vacuum responsive device 36 on the fuel inflow rate, the position of the flow restricting pin 92 on the piston end wall 56 may be adjusted by backing off the metering adjustment nut 136 and rotating the pin to a new axial position at which it is locked once again by tightening of the not 136.  
  Although a specific embodiment of the invention has been described, it will be appreciated that the invention is susceptible to modification, variation and change without departing from its proper scope as exemplified by the following claims.  
 What is claimed is:  
  l. in combination with an engine having a coolant circulating system fuel supply means and a throttle controlled carburetor for supplying a mixture of fuel and air at a regulated air-fuel ratio to the engine, vacuum responsive means connected to the carburetor and the fuel supply means for controlling the air-fuel ratio as a function of engine speed and load, and temperature responsive means connected to the fuel supply means and the coolant circulting system for varying the flow of fuel to the carburetor as a function of the engine temperature to automatically modify the influence of said vacuum responsive means on the flow of fuel wherein said carburetor includes a mixing space into which the fuel supply means and the vacuum responsive means project, said fuel supply means including a liquid fuel storing chamber spaced from the temperature responsive means, a vaporized fuel flow injection member, a flow injection member and means mounting said flow injection member and the control member for relative movement to vary the flow rate of vaporized fuel into the mixing space, one of said members being connected to the vacuum responsive means and the other of the members being operatively connected to the temperature responsive means.  
  2. The combination as set forth in claim 1 wherein said temperature responsive means includes coolant flow chamber means connected to the coolant circulating system independently of the fuel supply means, a temperature sensing device mounted within the chamber means, and actuating means connected t the sensing device for displacement of the said other of the members tending to make said fuel mixture more lean.  
  3. The combination as set forth in claim 2 wherein said fuel flow injection member includes a displaceable sealing portion (84) blocking flow of liquid fuel from the fuel storing chamber into the mixing chamber of the carburetor and a metering passage portion (88) extending from the displaceable portion into the mixing space having an outlet end 94 therein, and spring means engageable with the displaceable portion for biasing the metering passage portion to a position relative to the flow metering control member tending to increase the richness of the mixture of fuel and air.  
  4. The combination as set forth in claim 3 wherein the actuating means extends into the fuel storing chamber and engages the displaceable sealing portion of the fuel flow injection member.  
  5. The combination as set forth in claim 1 wherein said fuel flow injection member includes a displaceable sealing portion (84) blocking flow of liquid fuel from the fuel storing chamber into the mixing chamber of the carburetor and a metering passage portion (88) extending from the displaceable portion into the mixing space having an outlet end 94 therein, and spring means 100) engageable with the displaceable portion for biasing the metering passage portion to a position relative to the flow metering control member tending to increase the richness of the mixture of fuel and air.  
  6. The combination as set forth in claim 1 wherein said temperature responsive means includes coolant flow chamber means( 102) spaced from the fuel supply means, a temperature sensing device (114) mounted within the chamber means and actuating means 116) connected to the sensing device for regulating the fuel supply means only as a function of engine temperature.  
  7. The combination as set forth in claim 6 wherein said fuel supply means includes a source of liquid fuel (66) and fuel metering means 82) displaceable by the actuating means of the temperature responsive means for conducting a regulated flow of vaporized fuel the surce into the carburetor.  
  8. The combination as set forth in claim 1 wherein said fuel supply means includes a source of liquid fuel (66) and fuel metering means 82) displaceable by the temperature responsive means relative to the vacuum responsive means for conducting a regulated flow of vaporized fuel from the source into the carburetor.