GB1364999A - Internal combustion engine fuel control system having a full load - Google Patents

Abstract

1364999 Electronic fuel control systems for I C engines BENDIX CORP 20 Dec 1972 [20 Jan 1972] 58694/72 Heading G1N In an I. C. engine, electronic fuel control system, a full-load fuel enrichment circuit is provided to determine when engine operation extends into its full-load range to cause an additional amount of fuel to be supplied, the amount being dependent upon the extent of the operation into the full-load range. As shown in Fig. 3, alternate pulses are applied at 40, 42, in synchronism with engine rotation, to a generating circuit 60, each pulse causing the initiation of a charging voltage across a pair of capacitors, Fig. 5 (not shown) which each produce a waveform 90 as shown in Fig. 6. The portion A-D corresponds to the charging of one capacitor by a first current source during a pulse at 40 and the part above D corresponds to the charging of the same capacitor by a second current source during a pulse at 42. The second capacitor also produces the same waveform but phase displaced by the width of a pulse at 40 or 42 with respect to the waveform shown. The instantaneous output 66 of generator 60 is represented by the highest voltage across the two capacitors. This output is applied to the fuel enrichment circuit and to a circuit 62 which provides pulses for causing energization of injector valve means for their duration. The fuel enrichment circuit is shown in Fig. 4, the voltage on line 66 being compared with a reference voltage R which represent the lower limit of the full-load range. When the voltage on 66 reaches the reference voltage, a transistor 76 is switched which causes a transistor 80 to act as a current sink for one of the capacitors. Thus, the slope of the waveform 90 is reduced above the reference level R as shown in Fig. 6. The circuit 62 initiates a pulse 94 coincident with the generation of a pulse at 42, and compares the voltage on 66, i.e. the waveform 90, with a reference 92 which is determined by at least the intake air-pressure. When the voltage on 66 reaches the reference 92, the pulse 94 is terminated. The duration of pulse 94 determines the duration of injections. Thus, if the reference 92 is above the reference R, the pulse 92 is lengthened due to the change in slope of 90 above R. Other engine parameters, such as temperature, may be used to determine reference 92. Instead of using a current sink, the circuit 64 may add a current to one of the charging current sources, this current being cut-off when the reference R is exceeded.