Electronically controlled carburetor

An electronically controlled carburetor system for controlling the air-fuel mixture supplied by a carburetor to an internal combustion engine comprising:

• sensor means for sensing prescribed characteristics of selected physical parameters related to the operation of the engine;
• control means for controlling at least one of the amount of intake air and the amount of fuel supplied to the engine;
• and
• processing means responsive to output signals produced by said sensor means representative of said prescribed characteristics, for generating an output signal representative of a change in the density of the air taken into the engine, said output signal being coupled to said control means whereby said at least one of the amount of intake air and the amount of fuel supplied to the engine is controlled in accordance with said change in air density;
• and wherein
• said control means comprises an electromagnetic valve, to which said output signal is coupled, provided in a low-speed fuel path branching from the downstream part of a main metering orifice of said carburetor, and wherein said processing means generates said output signal so as to increase the duration of the opening of said electromagnetic valve until the amount of intake air reaches a prescribed quantity and thereafter maintaining the duration of opening of said valve constant.

An electronically controlled carburetor system for controlling the air-fuel mixture supplied by a carburetor to an internal combustion engine comprising:

• sensor means for sensing prescribed characteristics of selected physical parameters related to the operation of the engine;
• control means for controlling at least one of the amount of intake air and the amount of fuel supplied to the engine;
• and
• processing means, responsive to output signals produced by said sensor means representative of said prescribed characteristics, for generating an output signal representative of a change in the density of the air taken into the engine, said output signal being coupled to said control means whereby said at least one of the amount of intake air and the amount of fuel supplied to the engine is controlled in accordance with said change in air density;
• and wherein
• said control means comprises a change-over valve for closing either one of two low-speed fuel paths branched from respective upstream and downstream parts of a main fuel metering orifice of said carburetor, and a control valve for adjusting the amount of low-speed fuel after it passes through said change-over valve, and wherein said processing means selectively couples said output signal to said change-over valve and said control valve so that, as long as the amount of intake air is less than a prescribed quantity, said output signal causes said change-over valve to open the low-speed fuel path extending from the downstream part of said main fuel metering orifice and causes the degree of opening of said control valve to increase, and upon said amount of intake air reaching said prescribed quantity, said output signal causes said change-over valve to open the low-speed fuel path extending from the upstream part of said main fuel metering orifice and causes the degree of opening of said control valve to remain unchanged.

An electronically controlled carburetor system for controlling the air-fuel mixture supplied by a carburetor to an internal combustion engine comprising:

• sensor means for sensing prescribed characteristics of selected physical parameters related to the operation of the engine;
• control means for controlling at least one of the amount of intake air and the amount of fuel supplied to the engine;
• and
• processing means, responsive to output signals produced by said sensor means representative of said prescribed characteristics, for generating an output signal representative of a change in the density of the air taken into the engine, said output signal being coupled to said control means whereby said at least one of the amount of intake air and the amount of fuel supplied to the engine is controlled in accordance with said change in air density;
• and wherein
• control means comprises a control valve provided in a low-speed fuel path directly communicating with a float chamber of said carburetor and a change-over valve for opening and closing an air bleed path communicating with a main fuel supply system and a low-speed fuel supply system and wherein said processing means selectively couples said output signal to said change-over valve and said control valve so that, as long as the amount of intake air is less than a prescribed quantity, said output signal causes the degree of opening of said control valve to increase and said change-over valve to close said air bleed path and, upon said amount of intake air reaching said prescribed quantity, said output signal causes the degree of opening of said control valve to remain unchanged and said change-over valve to open said air bleed path.