Carburetor kit for improved air-fuel mixture

Apparatus for improving the emissions of internal-combustion engines having an engine fan generating a first air stream and a carburetor wherein an air-fuel mixture is produced by drawing fuel from a fuel float chamber into a second air stream flowing through a venturi tube as a result of a vacuum provided at an intake manifold, comprising:

• (a) first pneumatic passage means for connecting the float chamber of the carburetor and the first air stream, so that a positive pressure differential is available for application to the float chamber;
• (b) second pneumatic passage means for connecting the float chamber to a point upstream of a throttle in the venturi tube, so that a negative pressure differential is available for application to the float chamber when said throttle is at least partially open;
• (c) first valve means for controlling the flow rate through said first pneumatic passage means;
• (d) second valve means for controlling the flow rate through said second pneumatic passage means;
• (e) sensor means for measuring the oxygen content of the exhaust gases of the engine and for generating a signal corresponding to said oxygen content;
• and
• (f) electronic control means for actuating said first valve means in response to the signal generated by said sensor means, such that a flow rate through said first valve means is progressively reduced as the oxygen content in the exhaust gases decreases and is progressively increased as the oxygen content in the exhaust gases increases;
• and for actuating said second valve means in response to the signal generated by said sensor means, such that a flow rate through said second valve means is progressively reduced as the oxygen content in the exhaust gases increases and is progressively increased as the oxygen content in the exhaust gases decreases.

Apparatus for improving the emissions of internal-combustion engines having a carburetor wherein an air-fuel mixture is produced by drawing fuel from a fuel float chamber into an air stream flowing through a venturi tube as a result of a vacuum provided at an intake manifold, comprising:

• (a) first pneumatic passage means for venting the float chamber of the carburetor to atmosphere, so that an atmospheric pressure is available for application to the float chamber;
• (b) second pneumatic passage means for connecting the float chamber to the intake manifold, so that a negative pressure differential is available for application to the float chamber;
• (c) first valve means for controlling the flow rate through said first pneumatic passage means;
• (d) second valve means for controlling the flow rate through said second pneumatic passage means;
• (e) sensor means for measuring the oxygen content of the exhaust gases of the engine and for generating a signal corresponding to said oxygen content;
• and
• (f) electronic control means for actuating said first valve means in response to the signal generated by said sensor means, such that a flow rate through said first valve means is progressively reduced as the oxygen content in the exhaust gases decreases and is progressively increased as the oxygen content in the exhaust gases increases;
• and for actuating said second valve means in response to the signal generated by said sensor means, such that a flow rate through said second valve means is progressively reduced as the oxygen content in the exhaust gases increases and is progressively increased as the oxygen content in the exhaust gases decreases.

A method of improving the emissions of internal-combustion engines having an engine fan generating a first air stream and a carburetor wherein an air-fuel mixture is produced by drawing fuel from a fuel float chamber into a second air stream flowing through a venturi tube as a result of a vacuum provided at an intake manifold, comprising the following steps:

• (a) connecting the float chamber of the carburetor and the first air stream through first pneumatic passage means, so that a positive pressure differential is available for application to the float chamber;
• (b) connecting the float chamber and the intake manifold through second pneumatic passage means, so that a negative pressure differential is available for application to the float chamber;
• (c) providing first valve means for controlling the flow rate through said first pneumatic passage means;
• (d) providing second valve means for controlling the flow rate through said second pneumatic passage means;
• (e) providing sensor means for measuring the oxygen content of the exhaust gases of the engine and for generating a signal corresponding to said oxygen content;
• and
• (f) providing electronic control means for actuating said first valve means in response to the signal generated by said sensor means, such that a flow rate through said first valve means is progressively reduced as the oxygen content in the exhaust gases decreases and is progressively increased as the oxygen content in the exhaust gases increases;
• and for actuating said second valve means in response to the signal generated by said sensor means, such that a flow rate through said second valve means is progressively reduced as the oxygen content in the exhaust gases increases and is progressively increased as the oxygen content in the exhaust gases decreases.

A method for improving the emissions of internal-combustion engines having an engine fan generating a first air stream and a carburetor wherein an air-fuel mixture is produced by drawing fuel from a fuel float chamber into a second air stream flowing through a venturi tube as a result of a vacuum provided at an intake manifold, comprising the following steps:

• (a) connecting the float chamber of the carburetor and the first air stream through first pneumatic passage means, so that a positive pressure differential is available for application to the float chamber;
• (b) connecting the float chamber to a point upstream of a throttle in the venturi tube through second pneumatic passage means, so that a negative pressure differential is available for application to the float chamber when said throttle is at least partially open;
• (c) providing first valve means for controlling the flow rate through said first pneumatic passage means;
• (d) providing second valve means for controlling the flow rate through said second pneumatic passage means;
• (e) providing sensor means for measuring the oxygen content of the exhaust gases of the engine and for generating a signal corresponding to said oxygen content;
• and
• (f) providing electronic control means for actuating said first valve means in response to the signal generated by said sensor means, such that a flow rate through said first valve means is progressively reduced as the oxygen content in the exhaust gases decreases and is progressively increased as the oxygen content in the exhaust gases increases;
• and for actuating said second valve means in response to the signal generated by said sensor means, such that a flow rate through said second valve means is progressively reduced as the oxygen content in the exhaust gases increases and is progressively increased as the oxygen content in the exhaust gases decreases.

A method for improving the emissions of internal-combustion engines having a carburetor wherein an air-fuel mixture is produced by drawing fuel from a fuel float chamber into an air stream flowing through a venturi tube as a result of a vacuum provided at an intake manifold, comprising the following steps:

• (a) providing first pneumatic passage means for venting the float chamber of the carburetor to atmosphere, so that an atmospheric pressure is available for application to the float chamber;
• (b) connecting the float chamber to the intake manifold through second pneumatic passage means, so that a negative pressure differential is available for application to the float chamber;
• (c) providing first valve means for controlling the flow rate through said first pneumatic passage means;
• (d) providing second valve means for controlling the flow rate through said second pneumatic passage means;
• (e) providing sensor means for measuring the oxygen content of the exhaust gases of the engine and for generating a signal corresponding to said oxygen content;
• and
• (f) providing electronic control means for actuating said first valve means in response to the signal generated by said sensor means, such that a flow rate through said first valve means is progressively reduced as the oxygen content in the exhaust gases decreases and is progressively increased as the oxygen content in the exhaust gases increases;
• and for actuating said second valve means in response to the signal generated by said sensor means, such that a flow rate through said second valve means is progressively reduced as the oxygen content in the exhaust gases increases and is progressively increased as the oxygen content in the exhaust gases decreases.