Control system for regulating air/fuel ratio

A control system for an engine which burns combustible gas received from a carburetor having an element which is adjustable to regulate the air/fuel ratio of the mixture delivered to the engine, with the products of combustion being discharged through an exhaust conduit, comprising:

• a sensor, having a portion suitable for positioning in the exhaust conduit, to develop an electrical control signal varying in relation to the amount of at least one component gas in the discharged exhaust gas mixture;
• a control actuator adapted to be coupled to the adjustable element of the carburetor, and connected to receive an electrical regulating signal to regulate both the direction and the rate of actuator movement and correspondingly regulate movement of the element to change the air/fuel ratio;
• and
• a control circuit, coupled between the sensor and the control actuator, including means for establishing a reference signal, and means for continually comparing the control signal received from the sensor with the reference signal to provide the regulating signal for driving the control actuator in a direction to provide either a richer or leaner mixture, which control circuit continually functions and continually drives the actuator in one of two directions, thus establishing an average position of the carburetor adjustable element to produce a stoichiometric value of the air/fuel ratio, switching means coupled to the control actuator to regulate the direction of control actuator movement as a function of the sense of the regulating signal and also to regulate the rate of control actuator movement, an adjustable power supply coupled to said switching means for modifying the amplitude of said regulating signal and thus controlling the rate of control actuator movement, and means connected to supply an engine-speed-indicating signal to the adjustable power supply so that the rate of change of the air/fuel ratio is a function of engine speed.

A control system for an engine which burns combustible gas received from a fuel delivery device having an element which is adjustable to regulate the air/fuel ratio of the mixture delivered to the engine, with the products of combustion being discharged through an exhaust conduit, comprising:

• a sensor, having a portion suitable for positioning in the exhaust conduit, to develop an electrical control signal varying in relation to the amount of at least one component gas in the discharged exhaust gas mixture;
• a control actuator adapted to be coupled to the adjustable element of the fuel delivery device, and connected to receive an electrical regulating signal to regulate both the direction and the rate of actuator movement and correspondingly regulate movement of the element to change the air/fuel ratio;
• and
• a control circuit, coupled between the sensor and the control actuator, including means for establishing a reference signal, and means for continually comparing the control signal received from the sensor with the reference signal to provide the regulating signal for driving the control actuator in a direction to provide either a richer or leaner mixture, which control circuit continually functions and continually drives the actuator in one of two directions, thus establishing an average position of the adjustable element in the fuel delivery device to produce a stoichiometric value of the air/fuel ratio, switching means coupled to the control actuator to regulate the direction of control actuator movement as a function of the sense of the regulating signal and also to regulate the rate of control actuator movement, an adjustable power supply coupled to said switching means for modifying the amplitude of said regulating signal and thus controlling the rate of control actuator movement, and means connected to supply an engine-speed-indicating signal to the adjustable power supply so that the rate of change of the air/fuel ratio is a function of engine speed.