| 摘要 |
PURPOSE:To arrange a rate of excess air to 1, in air-fuel ratio control, by providing an FF circuit in which output of an O2 sensor is compared with the first reference voltage, if higher, assumed as excess fuel, and compared with the second reference voltage, if lower, assumed as excess air. CONSTITUTION:Output (a) of an O2 sensor 1 is voltage amplified to become a signal (c) to charge capacitors 4, 5 through diodes 6, 7. The capacitor 4 is connected with its one end to a power source Vcc and charged to voltage (d) higher by a voltage drop of the diode 6, while the capacitor 5 is connected with its one end to the earth and charged to constant voltage (e). In a comparator 8, if c>d, a positive pulse (h) is input to a set terminal s of an FF16, while in a comparator 9, if c<e, a positive pulse (i) is input to a reset terminal R. As a result, output (j) from the FF16 is reduced with delay times Tr, Tf at H L or L H of the sensor output (a), further reduced with a degree of unbalance. Accordingly, if fuel control is performed by the output (j), excess air and excess fuel are almost balanced, and a rate of excess air can be obtained to 1.0. |
