| 摘要 |
1,208,570. Fuel injection control system for I.C. engines. ASSOCIATED ENG. Ltd. Feb. 1, 1968 [Feb. 7, 1967], No.5878/67. Heading G1N. [Also in Division H3] In known fuel injection control systems (e.g. Specifications 1, 038, 541 and 1, 107, 989) for I.C. engines, wherein a pulse generator including a mono-stable multi-vibrator energizes electromagnetic injector valves to open the valve for a period depending on the duration of each pulse, the higher the supply voltage the more rapidly the injector valve will open, the reduction in opening time increasing the length of the open period; likewise a lower than normal supply voltage reduces the open period and quantity of fuel injected. In the present Specification the injection period is made independent of the supply voltage by the application of a bias voltage to the mono-stable multi-vibrator which bias varies as the supply voltage varies, to lengthen or shorten the period. Compensating for supply volts variation. As shown, a bias voltage V 6 applied to the emitters of TR 1 and TR 2 of the multi-vibrator is derived from a potential divider P which includes a non linear element Z 1 , e.g. a Zener diode or saturated diode. Since the voltage across Z 1 remains practically constant as its current increases (or decreases) with changes in the supply voltage, the voltage across the resistors of the potential divider including the bias voltage Vb, across Rb, will increase in proportion faster than the supply voltage V s . The voltage change across C1 which in part determines the pulse width is thus increased at a lesser rate than V s so that the width of the pulse energizing the valves is reduced to compensate for the shorter opening time at the increased supply voltage. Likewise the bias Vb decreases proportionally with decrease in V s . In the circuit shown the control voltage V 1 is derived from for example, engine speed, acceleration and/or inlet manifold pressure and the control voltage V 2 which affects the discharge of C 1 through TR 4 is derived from engine temperature, air temperature, starting and idling enrichment signals for example, as in Specification 1, 107, 989. |
