| 摘要 |
904,461. Electric control systems. BOSCH G.m.b.H., ROBERT. Nov. 26, 1958 [Nov. 27, 1957], No. 38054/58. Class 40 (1). [Also in Groups XXVII and XL (c)] The fuel injection valve of an I.C. engine is opened during the unstable state of a monostable transistor flip-flop circuit which is changed over once per revolution for each cylinder by a cam driven by the engine shaft, and returns to its stable state after a time period determined by the speed of the engine, the position of the throttle lever, and the temperature and pressure of the air. As shown (Fig. 1), the valve cone 35 of a fuel injection valve 33 is raised to allow fuel to be injected into the intake pipe 30 of an I.C. engine 10 when coil 34 is energized by the output of an amp ifier 28, which occurs when normally conducting transistor T 2 is cut off by transistor T 1 conducting after switch 39 has been closed by cam 38 driven by the motor shaft 11. The duration of the cut-off is determined partly by the potential at the emitter E 2 of transistor T 2 and partly by the discharge time of capacitor 58 through its shunt resistors 59, 60, resistor 59 being sensitive to atmospheric temperature and pressure. Motor shaft 11 drives a second cam 25 to cyclically close a switch 27, when capacitor 76 is charged through the emitter-base path of transistor T 3 , and capacitor 78 is also simultaneously charged, to be discharged through a potentiometer resistor R when switch 27 is open. Since the charging time of capacitor 78 is determined only by the values of capacitor 76 and resistor 77, and is therefore constant, and its discharge time depends on the period between successive closures of switch 27, the average voltage across capacitor 78, and potentiometer R, is higher at higher motor speeds, and thus reduces the time during which transistor T 2 is non-conducting, and valve cone 35 is raised. The voltage at the emitter Eg is further controlled by the position of the slider of potentiometer R, which is mechanically linked to the throttle lever 81. |
