摘要:
A fuel control system for an internal combustion engine includes an exhaust gas sensor from which feedback control signal is derived, a limiter for limiting the maximum and minimum voltages of the control signal and a triangular wave generator. The triangular wave has a constant amplitude peak of which the maximum value is slightly greater than the maximum voltage of the control signal and the minimum value is slightly below the minimum voltage of the control signal. A comparator is provided to produce an output at one of two binary levels depending upon whether the control signal is above or below the instantaneous value of the triangular wave. The output from the comparator is a train of pulses whose duty cycle ranges from predetermined minimum to maximum values which correspond respectively to the minimum open and closure times of air-fuel mixing control valves.
摘要:
A reference voltage, which is compared with an output voltage of an exhaust gas sensor in a differential signal generator of an electronic closed loop air-fuel ratio control system, changes depending upon a mean value of an output of the exhaust gas sensor provided in an exhaust pipe extending from an internal combustion engine. Furthermore, the magnitude of the reference voltage is limited in such a manner as to be within a predetermined range, or in other words, the magnitude of the reference voltage is limited at at least one of an upper and a lower values thereof.
摘要:
A fuel supply control system is disclosed which uses a stored program type digital computer for calculating a basic amount of fuel and modifying the basic amount in accordance with various correction factors dependent upon engine operating conditions so as to determine an actual amount of fuel supplied to an engine. The actual fuel amount is determined by adding all correction factors dependent upon engine temperature and multiplying the sum by the basic fuel amount.
摘要:
The variation range defined between the maximum and the minimum output voltages of a gas sensor in the exhaust passage is detected and compared with a reference signal which can have hysterisis characteristics. Engine operational parameters are utilized to disable and/or reactivate the system as well as the sensed sensor response, while the air-fuel ratio can be arbitrarily varied to test if the sensor is below an effective working temperature and reactivate the system.
摘要:
Emission control apparatus for internal combustion engines is provided with a sensor for detecting the concentration of a particular exhaust composition in the emissions from the engine. A signal indicating the deviation of the mixture ratio from a controlled point is generated by comparing the output from the sensor with a reference level, the signal being modified in amplitude according to a predetermined control characteristic and used to regulate the air-fuel mixture ratio at the desired control point. The varying magnitude of the sensed concentration is smoothed into a signal of slowly varying magnitude which is used to control the reference level so that error introduced into the deviation indicating signal due to the change with time in the output performance of the exhaust composition sensor is self-compensated. A level sensor is provided to detect when the reference level reaches an end of the control range to change the operating mode of the engine from closed-loop to open-loop mode.
摘要:
A circuit is provided in an electronic closed loop air-fuel ratio control system for starting and terminating the operation of the system at different voltages from an exhaust gas sensor.
摘要:
In a fuel mixture control system including an exhaust gas sensor located within an exhaust system of an internal combustion engine, maximum and minimum peak values of the gas sensor output are detected. A direct-current pedestal is added to the detected minimum peak value. A comparator detects when the added minimum peak exceeds the detected maximum peak value to provide a disabling signal to the mixture control system to switch its operational mode from closed loop control to open loop control when the temperature of the gas sensor falls below its operating temperature typically during prolonged idle condition.
摘要:
A reference signal with which the output of a gas sensor is compared is produced by detecting the maximum and minimum values of the output of the gas sensor and adding via a voltage divider these values to each other. The variation of the reference signal may be limited with predicted maximum and minimum values of the output of the gas sensor. The reference signal produced in such a manner may be utilized for disabling and reactivating the feedback control.
摘要:
In a mixture control system having an exhaust gas sensor located in an exhaust system of an internal combustion engine for controlling the air-fuel ratio of the mixture supplied to the engine, a detection system for detecting when the temperature of the exhaust gas sensor is within its normal operating range. A deviation signal is derived from the exhaust gas sensor to represent the deviation of the air-fuel ratio within the exhaust system from a desired air-fuel ratio. The peak value of the deviation signal is detected and stored in a storage circuit and compared with a threshold which represents the normal operating temperature of the exhaust gas sensor to provide a disabling signal for the mixture control system to suspend feedback control operation when the temperature of the sensor falls below its normal operating temperature. The exhaust gas sensor is then supplied with a current in response to the presence of the disabling signal so that the voltage across the sensor's internal impedance increases because of its high impedance value at low sensor temperatures. The output from the gas sensor is compared with a preset value higher than the maximum output level of the sensor when operating at or above its normal operating temperature but lower than the minimum output level of the sensor when operating below its normal operating temperature with the current being fed. When the gas sensor output falls below the preset value, the system determines that the temperature of the gas sensor has risen above its normal operating temperature to resume feedback control operation.
摘要:
A closed-loop emission control apparatus for internal combustion engines includes exhaust composition sensor for feedback control of the air-fuel mixture. When the temperature in the exhaust passage is lower than the operating temperature of the sensor, control is switched to an open-loop mode. The feedback control signal is fluctuated above and below a predetermined DC bias at periodic intervals during the open-loop mode to switch the control to the closed-loop mode in a minimum transition time as soon as the sensor's temperature condition warrants feedback control.