GB1257860A - - Google Patents

Abstract

1,257,860. Fluid logic and switching circuits; regulating I.C. engine fuel supply; spray carburetters. NIPPONDENSO K.K. Dec. 23, 1969 [Dec.27, 1968; May 12, 1969; May 15, 1969; June 5, 1969; July 8, 1969], No.62644/69. Headings F1B and F1P. A fuel supply system for an I.C. engine comprises a continuously fed fuel ejecting nozzle 2, Fig. 1, located in the engine air intake tube 1, a fuel receiver 3 adapted to selectively receive fuel from nozzle 2 and return it to a reservoir (not shown), an air ejecting nozzle 4 supplied with air pulses from the output 11, Fig. 2, of a fluid multi-vibrator unit 6a whereby the fuel jet is deviated and the air intake tube is supplied with that portion of the fuel jet that is not received by the receiver; the vibrator unit having a constant air supply input at 7, a pulsating air control input at 8 derived from an air trigger pulse generator 17 synchronously driven by the engine and means for controlling the duration of each output of the vibrator. The trigger pulses are generated by intermittent closing of a vent port 19 in a branch 23 of the delivery line 21 of a compressor 15 by an engine driven rotor 18, and the duration as distinct from the frequency of the pulses at output 11 are controlled by feeding them through a capacitor 12 and a variable throttle 13 to a control input 9 of the vibrator unit 6a. In a modification fuel from a nozzle 123, Fig. 5, is directed through a passage 124 into the air intake 118 unless deviated by pulses from air ejecting nozzle 125 into a fuel receiver chamber 122 connected through a port 127 to fuel reservoir 128. Also the control input 104c of vibrator 103 is supplied with air pulses from generator 108 which are shortened in duration by means of a vibrator unit 107 and the duration of pulses at the output 104e of vibrator 103 is controlled by varying the volume of a chamber 105c in the feedback line from vented output 104d to control input 104b. Chamber 105c is bounded by a piston 105b which is moved to the right against a biasing spring when the throttle 120 to which the piston rod 105k is linked by 135 is moved to its closed position. The piston 105b is also moved to the right to reduce the volume of chamber 105c by a reduction in pressure in suction tube 119 and which is transmitted through ports 134, 105h to a chamber 105#. As volume of chamber 105c becomes smaller the duration of the air pulses at output 104d become shorter and those at output 104e become longer and hence less fuel is ejected into suction passage 118. In a further modification wherein the disposition of fuel ejector nozzle 203, Fig. 8, air ejecting nozzle 205 and fuel receiver 204 is similar to that shown in Fig. 1, the control input at 212 of vibrator assembly 211 is formed by pulses generated by 227 and rectified at 232 together with the continuous output 225 of a OR-NOR element 222 which output exists only at low input pressures at 223, 224 derived respectively from the output 221 of a proportional amplifier 219 and an analogue type pressure converter 228 driven from the engine. In operation and at low engine speed and low negative pressure in a line 218 connected to the suction manifold 202, output 225 which is applied to control input 212 delays switching of the output 216 of vibrator 211a to vent 215 thus increasing the duration of pulses fed to the air ejector nozzle 205 and reduces the fuel air ratio in air suction tube 201. In a still further embodiment similar to that shown in Fig. 5, a fuel pump shut-off switch (437) Fig. 13 (not shown) opens the power circuit of the fuel pump when air supply to the compressor 101 fails. Also an air ejecting nozzle (439) supplied by compressor 101 via a check valve (438) ejects air towards the exhaust valve 117.