GB1356060A - Electrically controlled fuel injection systems for internal com bustion engines - Google Patents

Abstract

1356060 Fuel injection systems ROBERT BOSCH GmbH 22 Dec 1971 [23 Dec 1970] 59769/71 Heading G1N In an I. C. engine intermittant fuel injection system, the duration of the injection valve actuating pulse S is controlled in dependence upon air intake quantity Q which is determined by a temperature dependent resistor 30 arranged in the intake 25 of the engine 10 and provided with a heating current Jh so as to maintain its temperature substantially constant, a voltage Us dependent upon the heating current Jh being applied to a plurality of amplifying networks A1-A4 having different responses and amplification factors so that a summing amplifier 40 provides a voltage Uk, as shown in Fig. 3, which is matched to the air intake quantity Q. This voltage is applied to an integrating device 37 which is charged, over a predetermined crankshaft angle, in dependence upon the voltage Uk, the discharge time then determining the duration ti of the injection valve actuating pulses S provided by a differentiating device 38. As shown, the resistor 30 is included in a bridge network whose out-of-balance voltage is applied to a regulator R for regulating the heating current Jh. The integrator 37, Fig.6 (not shown), includes a capacitor in the feedback of an operational amplifier, the capacitor being charged in synchronism with engine rotation by a switch 46 and bi-stable multi-vibrator 48, for 180 degrees crank-shaft rotation, the capacitor then being discharged. The bi-stable multi-vibrator operates transistor switches in the integrator for this function. The amplifying networks A1 - A4, Fig. 4 (not shown) each include an operational amplifier whose response and amplification factor is adjustable to provide the desired voltage function Uk in the summing amplifier 40, Fig. 5 (not shown).