device for regulating the luchtgetal labda of a verbrandingsinrichting added fuel air mixture.

摘要

1386429 Regulating I C engine ROBERT BOSCH GmbH 30 March 1972 [2 April 1971] 14960/72 Heading F1B [Also in Divisions G1 and G3] The fuel/air mixture supplied to an I. C. engine is regulated in dependence upon the composition of the exhaust gases of the engine utilizing at least one gas probe, the/or at least one of the probes comprising an oxygen ion conductive solid electrolyte whose output signal is fed to an electronic control circuit via a low pass filter. In an intermittent fuel injection system, Fig. 1 and Figs. 2, 4, 5, 6, and 9 (not shown), the signal representing oxygen content regulates the duration of each energization of the injection valve, and in a carburetter system, Fig. 3 (not shown), the signal regulates the position of an auxiliary air throttle. As shown, the intermittent fuel injection system includes the oxygen sensor 21 whose output is applied to a threshold circuit 23 via the low pass filter 22, the output of the circuit 23 being fed to one input of a control multi-vibrator 30 via a limiting network 25. The multi-vibrator is triggered in synchronism with engine rotation, and its pulses energize an injection valve 28. The duration of the pulses is determined by the output of the limiting network 25 and by other parameters. In operation, the multi-vibrator is normally set to produce an air/fuel ratio slightly in excess of that desired so as to produce a higher than desired oxygen content. Thus, the circuit 23 is triggered to increase the pulse period of the multivibrator to produce an air/fuel ratio slightly less than that desired. A two step regulation is thereby achieved. In a modification, Fig. 2 (not shown), the output of the filter 22 is applied to a pair of differentiating amplifiers which operate so that one responds to excess oxygen signals and the other to insufficient oxygen signals. One of the amplifiers operates to vary the pulse duration of the multivibrator, while the other operates to vary the pulse duration of a multiplying circuit which is operative to extend the pulses of the multi-vibrator. In an improvement of the above modification Figs. 5 and 6 (not shown), the carbon monoxide content or temperature of the exhaust gases is also utilized, and a function generator is provided to regulate air/fuel ratios for different engine operating condition, e.g no-load, intermediate load, and full load conditions. In a further modification, Fig. 9 (not shown), temperature compensation is provided by utilizing a temperature sensor in the exhaust manifold. Until the temperature reaches a pre-set value, the oxygen sensor signal is not utilized. Alternatively, the oxygen sensor may be provided with a heater.