Apparatus for reducing hydrocarbon content of engine exhaust gases during decelaration of automobile

Claim 2

In a carburetor for an automotive gasoline-powered internal combustion engine and having a main mixture supply flow path leading to the intake manifold of said engine and kept substantially closed by a butterfly valve mounted therein during the idle and decelerating operations of the automobile and a slow running mixture supply flow path which is adapted to supply said engine with an air-fuel mixture having a predetermined air-fuel ratio during said operations and which includes first and second air bleeds which are vented to the atmosphere, a liquid fuel passage leading from a fuel source and communicating with said first and second air bleeds, a mixture passage for passing the air delivered from said first and second air bleeds and fuel delivered from said fuel passage, a slow running port communicating with said mixture passage and opening into said main mixture supply path at a position where said butterfly valve substantially closes the last named path during the idling and decelerating operations and an idling port communicating with said slow running port and opening into said main mixture supply flow path downstream of said butterfly valve, a system for reducing the quantity of unburned hydrocarbons in the exhaust gases emitted from said engine during the decelerating operation of the automobile, said system comprising a diaphragm valve assembly which is divided by a diaphragm member into atmospheric and suction chambers, of which the atmospheric chamber is vented to the atmosphere and has accommodated therein a valve member secured to said diaphragm member and inserted operatively into said idling port and of which the suction chamber communicates with the intake manifold of said engine by way of a suction conduit and has accommodated therein a coil spring which acts to normally hold said valve member in a position to close said idling port during the idling operation, said diaphragm member being provided therein with an opening permitting said atmospheric chamber to communicate with said suction chamber, said atmospheric chamber being provided therein with a stopper for restricting the displacement of said valve member and serving to isolate said atmospheric chamber from the atmosphere while said valve member remains in a position to close said idling port for thereby blocking communication between said suction chamber and the atmosphere during the idling operation, wherein, as an increased vacuum develops at the intake manifold of the engine during the decelerating operation, said diaphragm member is displaced by the increased vacuum exercised thereto through said suction conduit and against the action of said coil spring in a direction to cause said valve member to withdraw from said idling port and to permit the atmospheric chamber to communicate with the suction chamber, whereby an increased amount of the air-fuel mixture is delivered into said main mixture supply flow path and simultaneously atmospheric air is introduced into the intake manifold of the engine by way of said atmospheric chamber, suction chamber and suction conduit.

Claim 3

The system as set forth in claim 3, wherein said suction conduit is provided at a suitable location thereof with an orifice for metering the amount of air to be introduced into the intake manifold of the engine.

Claim 4

In a carburetor for an automotive gasoline-powered internal combustion engine and having a main mixture supply flow path leading to the intake manifold of said engine and kept substantially closed by a butterfly valve mounted therein during the idling and decelerating operations of the automobile and a slow running mixture supply flow path which is adapted to supply said engine with an air-fuel mixture having a predetermined air-fuel ratio during said operations and which includes first and second air bleeds which are vented to the atmosphere, a liquid fuel passage leading from a fuel source and communicating with said first and second air bleeds, a mixture passage for passing air delivered from said first and second air bleeds and fuel delivered from said fuel passage, a slow running port communicating with said mixture passage and opening into said main mixture supply path at a position where said butterfly valve substantially closes the last named path during the idling and decelerating operations and an idling port communicating with said slow running port and opening into said main mixture supply flow path downstream of said butterfly valve, a system for reducing the quantity of unburned hydrocarbons in the exhaust gases emitted from said engine during the decelerating operation of the automobile, said system comprising a deceleration port communicating with said idling port and opening into said main mixture supply flow path downstream of said butterfly valve and a diaphragm valve assembly which is divided by a diaphragm member into atmospheric and suction chambers, of which the atmospheric chamber is vented to the atmosphere and has accommodated therein a valve member secured to said diaphragm member and inserted operatively into said deceleration port and of which the suction chamber communicates with the intake manifold of the engine by way of a suction conduit and has accommodated therein a coil spring which normally acts to hold said valve member in a position to close said deceleration port during the idling operation, wherein, as an increased vacuum develops at the intake manifold of the engine during the decelerating operation, said diaphragm member is displaced with the increased vacuum exercised thereto through said suction conduit and against the action of said coil spring in a direction to cause said valve member to withdraw from said deceleration port, whereby an increased amount of the air-fuel mixture is allowed into said main mixture supply flow path through said deceleration port during the decelerating operation.

Claim 5

The system as set forth in claim 5, wherein said valve member has its end tapered and said idle port has provided at the inner wall thereof with a constriction, whereby the amount of said mixture to be delivered into said main mixture supply flow path during the decelerating operation is increased continuously as the tapered end of said valve member passes said constriction.

Claim 6

In a carburetor for an automotive gasoline-powered internal combustion engine and having a main mixture supply flow path leading to the intake manifold of said engine and kept substantially closed by a butterfly valve mounted therein during the idling and decelerating operations of the automobile and a slow running mixture supply flow path which is adapted to supply said engine with an air-fuel mixture having a predetermined air-fuel ratio during said operations and which includes first and second air bleeds which are vented to the atmosphere, a liquid fuel passage leading from a fuel source and communicating with said first and second air bleeds, a mixture passage for passing air delivered from said first and second air bleeds and fuel delivered from said fuel passage, a slow running port communicating with said mixture passage and opening into said main mixture supply path at a position where said butterfly valve substantially closes the last named path during the idling and decelerating operations and an idling port communicating with said slow running port and opening into said main mixture supply flow path downstream of said butterfly valve, a system for reducing the quantity of unburned hydrocarbons in the exhaust gases emitted from said engine dUring the decelerating operation of the automobile, said system comprising a deceleration port communication with said idling port and opening into said main mixture supply flow path downstream of said butterfly valve and a diaphragm valve assembly which is divided by a diaphragm member into atmospheric and suction chambers of which the atmospheric chamber is vented to the atmosphere and has accommodated therein a valve member secured to said diaphragm member and inserted operatively into said deceleration port and of which the suction chamber communicates with the intake manifold of the engine by way of a suction conduit and has accommodated therein a coil spring which acts to normally hold said valve member in a position to close said deceleration port during the idling operation, said diaphragm member being provided therein with an opening permitting said atmospheric chamber to communicate with said suction chamber, said atmospheric chamber being provided therein with a stopper for restricting the displacement of said valve member and serving to isolate said atmospheric chamber from the atmosphere while said valve member remains in a position to close said deceleration port for thereby blocking communication between said suction chamber and the atmosphere during the idling operation, wherein, as an increased vacuum develops at the intake manifold of the engine during the decelerating operation, said diaphragm member is displaced with the increased vacuum exercised thereto through said suction conduit and against the action of said coil spring in a direction to cause said valve member to withdraw from said deceleration port and to permit said atmospheric chamber to communicate with said suction chamber, whereby an increased amount of air-fuel mixture is delivered into said main mixture supply flow path and simultaneously atmospheric air is introduced into the intake manifold of the engine by way of said atmospheric chamber, suction chamber and suction conduit.

Claim 7

The system as set forth in claim 7, wherein said suction conduit is provided at a suitable location thereof with an orifice for metering the amount of air to be introduced into the intake manifold of the engine.

Claim 8

In a carburetor for an automotive gasoline-powered internal combustion engine and having a main mixture supply flow path leading to the intake manifold of said engine and kept substantially closed by a butterfly valve mounted therein during the idling and decelerating operations of the automobile and a slow running mixture supply flow path which is adapted to supply said engine with an air-fuel mixture having a predetermined air-fuel ratio during said operations and which includes first and second air bleeds which are vented to the atmosphere, a liquid fuel passage leading from a fuel source and communicating with said first and second air bleeds, a mixture passage for passing air delivered from said first and second air bleeds and fuel delivered from said fuel passage, a slow running port communicating with said mixture passage and opening into said main mixture supply path at a position where said butterfly valve substantially closes the last named path during the idling and decelerating operations and an idling port communicating with said slow running port and opening into said main mixture supply flow path downstream of said butterfly valve, a system for reducing the quantity of unburned hydrocarbons in the exhaust gases emitted from said engine during the decelerating operation of the automobile, said system comprising: a solenoid valve assembly having a valve member which is operatively inserted into said idling port and a coil spring which acts to normally hold said valve member in a position to close said idling port; and a diaphragm switch assembly which is linked through a wire circuit with said solenoid valve assembly and which is adapted to cause the same to be energized in response to an increase in the vacuum at the intake manifold of the engine, wherein, as an increased vacuum develops aT the intake manifold during the decelerating operation said diaphragm switch assembly is actuated to cause said solenoid valve assembly be energized to force said valve member to withdraw from said idling port against the action of said coil spring, whereby an increased amount of the air-fuel mixture is allowed into said main mixture supply flow path during the decelerating operation.

Claim 9

The system as set forth in claim 9, wherein the interior of said solenoid valve assembly is opened to the atmosphere through an air vent and communicates with the intake manifold of the engine by way of a conduit, said air vent being isolated from the intake manifold while said valve member is held in a position to close said idling port, viz, during the idling operation, wherein, as said valve member is moved in a direction to open said idling port in response to the increase in the vacuum at the intake manifold during the decelerating operation, said air vent is permitted to communicate with the intake manifold through said conduit, whereby atmospheric air is introduced into the intake manifold during the decelerating operation.

Claim 10

The system as set forth in claim 10 wherein said conduit is provided at a suitable location thereof with an orifice for metering the flow rate of air to be allowed into the intake manifold of the engine.

Claim 11

In a carburetor for an automotive gasoline-powered internal combustion engine and having a main mixture supply flow path leading to the intake manifold of said engine and kept substantially closed by a butterfly valve mounted therein during the idling and decelerating operations of the automobile and a slow running mixture supply flow path which is adapted to supply said engine with an air-fuel mixture having a predetermined air-fuel ratio during said operations and which includes first and second air bleeds which are vented to the atmosphere, a liquid fuel passage leading from a fuel source and communicating with said first and second air bleeds, a mixture passage for passing to said main mixture supply flow path air delivered from said first and second air bleeds and fuel delivered from said fuel passage, a system for reducing the quantity of unburned hydrocarbons emitted from said engine during the decelerating operation said system comprising a bypass passage branched from said mixture passage and communicating with said main mixture supply flow path downstream of said butterfly valve, a valve assembly having a valve member, a coil spring and a valve seat, said valve seat being normally forced against said valve member by means of said coil spring for closing said bypass passage during the idling operation, wherein, as an increased vacuum develops at the intake manifold of said engine during the decelerating operation, said valve member is pulled by said increased vacuum against the action of said coil spring for thereby opening said passage, whereby the air-fuel mixture fed via said bypass passage is prohibited and permitted to enter said main mixture supply flow path during the idling and decelerating operations, respectively.

Claim 12

The system as set forth in claim 12, wherein said valve member is a ball check valve member.