Liquefied propane carburetor modification system

• US 4,369,751 A
• Filed: 08/13/1980
• Issued: 01/25/1983
• Est. Priority Date: 08/13/1980
• Status: Expired due to Term

• Current Assignee: Ayres Technologies Incorporated
• Original Assignee: Ayres Technologies Incorporated
• Inventors: Batchelor, Douglas R., Batchelor, William H.
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Cross, E. Rollins
• Application Number:
  US06/177,790
• Time in Patent Office: 895 Days
• Field of Search: 123/525, 123/527, 123/590, 123/489, 48/180 R, 48/180 C, 220/3, 220/445, 220/900, 62/49
• US Class Current: 123/672
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 43/00 Engines characterised by operating on gaseous fuels; Plants including such engines engines characterised by the gas-air charge being ignited by compression ignition of an additional fuel F02B7/06; engines convertible from gas to other fuel consumption F02B69/04
• CPC Class Codes: F02D 19/027 Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
• CPC Class Codes: F02M 13/08 Carburettors adapted to use liquid and gaseous fuels, e.g. alternatively
• CPC Class Codes: F02M 21/0212 comprising at least 3 C-Atoms, e.g. liquefied petroleum gas [LPG], propane or butane
• CPC Class Codes: F02M 21/0239 Pressure or flow regulators therefor
• CPC Class Codes: F02M 21/042 Mixer comprising a plurality of bores or flow passages
• CPC Class Codes: F02M 21/06 Apparatus for de-liquefying, e.g. by heating
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A system which can be retrofit into an existing conventional gasoline powered vehicle for enabling the vehicle to operate on either gasoline or liquefied propane fuel. The system includes a mixer in the form of an adapter to fit on the top of an existing carburetor. The mixer has a unique spring balanced metering device which controls flow of gaseous propane to the carburetor in proportion to airflow through the carburetor. The mixer is connected to a regulator assembly which receives liquid propane in a first chamber, heats the liquid propane to form a vapor, and feeds the vapor through an idle valve to control idling of the engine. The vapor is also passed to a second chamber of the regulator assembly in response to demand from the metering device which is sensed by a diaphragm actuated gas flow valve. From the second chamber, the gaseous propane is fed to a high speed inlet of the mixer. Engine manifold vacuum is also used to provide additional control for the gas flow valve to increase efficiency of the system. Other features include a special purpose fuel tank and an optional exhaust system oxygen sensor for further regulating gas flow to the engine.

Claims

1. In an internal combustion engine having an engine block, at least one combustion chamber, an intake manifold for channeling fuel to said combustion chamber and a carburetor mounted on said intake manifold, the improvement comprising a storage tank for storing liquefied gaseous fuel;

a regulator and vaporizer means for vaporizing said liquefied gaseous fuel and regulating the flow of said liquefied gaseous fuel, said vaporizer and regulator means including a first chamber for receiving said liquefied gaseous fuel from said tank, said first chamber having a first outlet port containing a gaseous fuel flow regulator, said first outlet port being connected to said intake manifold, and a second chamber containing a second outlet port, said second chamber being divided into upper and lower portions by a diaphragm, valve means actuated by said diaphragm for selectively communicating said second chamber with said first chamber; and

mixer means connected to said carburetor, said mixer means having an inlet port connected to said second outlet port for receiving gaseous fuel therefrom and mixing said gaseous fuel with combustion air, said mixer means defining a venturi structure including large cross sectional area inlet and outlet ends and a smaller cross sectional area midportion intermediate said large cross sectional area ends and further defining a gas receiving chamber disposed substantially entirely about said venturi passage and with which said inlet port is communicated, said smaller cross sectional area midportion of said venturi structure including at least a substantially continuously peripheral slot formed therein opening outwardly from the outer periphery of said smaller cross sectional area midportion into the immediately surrounding portions of said gas receiving chamber and communicating the latter with the outer periphery of the smaller cross sectional area venturi midportion, said large cross-sectional area outlet end being communicated with said intake manifold and said large cross sectional area inlet end being adapted to receive filtered induction air.

2. The invention as defined in claim 1 wherein said storage tank includes an outer shell and an inner shell, said inner shell being mounted centrally of and perimetrically spaced from said outer shell.

3. The invention as defined in claim 2 wherein said inner shell further includes at least two pressure sensor means, one of said pressure sensor means being mounted through the top of said inner shell for measuring the pressure in the top portion of said inner shell and the other of said pressure sensor means being mounted through the bottom of said inner shell for measuring the pressure in the bottom portion of said inner shell, and circuit means for receiving the outputs of said pressure sensors and producing a signal proportional to the fuel level in said inner shell.

4. The invention as defined in claim 3 and further including vent means for communicating the space between said inner and outer shells to the surrounding atmosphere.

5. The invention as defined in claim 1 and further including vacuum operated diaphragm means connected to said intake manifold for yieldably resisting movement of said second chamber diaphragm in response to increases in vacuum in said intake manifold.

6. The invention as defined in claim 5 and further including exhaust gas analyzer means for sensing pollutants in the exhaust of said internal combustion engine and restricting movement of said diaphragm in response to an excess level of pollutants.

7. The invention as defined in claim 6 wherein said exhaust gas analyzer means comprises an oxygen sensor.

12. The invention as defined in claim 1 including heating means in said first chamber for heating said liquefied gaseous fuel and thereby vaporizing the latter.

8. An internal combustion engine having an induction system including an intake manifold for channeling intake air to a combustion chamber of said engine, a storage tank for storing liquefied gaseous fuel under pressure, a regulator and vaporizer means for receiving liquefied fuel from said tank, reducing the pressure of received fuel and vaporizing the fuel, air and vaporized fuel mixer means connected to said intake manifold, said mixer means including at least one inlet port for air and defining a venturi zone of reduced cross-sectional airflow area, said mixer means including a gaseous fuel chamber to which gaseous fuel is supplied from said vaporizer means and from which gaseous fuel is discharged into said venturi zone at points spaced thereabout, said induction system including adjustable airflow throttling means disposed downstream from said mixer means, said venturi zone being defined by a venturi structure including large cross-sectional area inlet and outlet ends and a smaller cross-sectional area midportion intermediate said large cross-sectional ends, said fuel chamber including portions thereof disposed substantially entirely about said smaller cross-sectional area midportion, said smaller cross-sectional area midportion of said venturi structure including at least a substantially continuous peripheral slot formed therein opening radially outwardly from said smaller cross-sectional area midportion into said portions of said chamber and thereby communicating the latter with the outer periphery of said smaller cross-sectional area midportion, said large cross-sectional area outlet end being communicated with said intake manifold and said large cross-sectional area inlet end being adapted to receive filtered induction air.

9. The combination of claim 8 wherein said points of discharge of gaseous fuel about said venturi zone comprise spaced portions of said substantially continuous peripheral slot extending about said venturi zone.

10. The combination of claim 9 including a combined pressure differential and airflow responsive valve associated with said port for opening and throttling said port upon increases and decreases in demand of intake air to said combustion chamber.

11. The combination of claim 8 wherein said mixer means also defines a second inlet port for air including a corresponding venturi zone, said second port being smaller in cross-sectional area than said first port, said mixer means defining a second gaseous fuel chamber to which gaseous fuel is supplied from said vaporizer means and from which gaseous fuel is discharged into the venturi zone of said second port at points spaced thereabout.