GB1252070A - - Google Patents

Abstract

1,252,070. Fuel injection systems. ROBERT BOSCH G.m.b.H. March 27, 1969 [March 28, 1968], No. 15969/69. Heading G1N. In an I. C. engine fuel injection system, a single control monostable multi-vibrator supplies opening pulses to a plurality of solenoid valves, and at least one storage device is provided to supply a prolongation pulse which immediately follows the basic pulse of the multi-vibrator, the duration of this basic pulse being dependent upon at least one engine operating parameter, e.g. intake manifold pressure, and the duration of the prolongation pulse being dependent upon the duration of the basic pulse. In this way the valves are operated with mutually overlapping injection period. As shown, solenoid valves 21-24 are opened in a desired sequence by switches 11-14, e.g. in the ignition distributer. As each switch is closed, a bi-stable multi-vibrator 32 is triggered which triggers monostable multi-vibrator 33 into an unstable state while applying a signal to one of the AND gates 34 or 39. During the unstable period of multi-vibrator 33 a pulse is applied to a respective valve, via an OR gate 36 or 41 and an amplifier 51 or 52, and the storage device 35 or 40 commences to charge. When multi-vibrator 33 returns to its normal state, the storage device 35 or 40 discharges to provide the prolongation pulse. The storage device may include a capacitor (83), Fig. 3 (not shown), which may be charged and discharged linearly to provide a proportional relationship between the basic pulse and the prolongation pulse, or controlled by an engine operating parameter to provide a desired relationship between these pulses. In an alternative, each valve is provided with a storage device with a distributer, e.g. a logic circuit, connected between multi-vibrator 33 and the individual storage devices. In a modification, Fig. 4 (not shown), the output of each OR gate 36, 41 is split into two channels, each channel containing an AND gate and an amplifier connected to a respective valve 21-24, and the switches 11-14 are connected to respective AND gates in the channels. In a modification of the latter embodiment, Figs. 5-7 (not shown), switching is effected electronically by connecting pairs of switches 11, 13 and 12, 14 to the bi-stable multi-vibrator 32 via respective bi-stable multivibrators (30), (31), the outputs of the latter multivibrators being connected to respective AND gates in the channels. In an eight-cylinder I. C. engine, further valves (25)-(28), Fig.4 (not shown), are connected in parallel with valves 21-24, the valves operating in pairs. In Figs. 8-10 (not shown), two valves or groups of valves are operated which are opened alternatively and whose periods overlap. This injection system is intended for operating a rotary piston engine.