KRAFTSTOFFREGLER

摘要

1523390 Pressure fed carburetters BORG WARNER CORP 11 June 1976 [15 Sept 1975] 24358/76 Heading F1B [Also in Division G3] A fuel supply system comprises a regulator 12 including a body 51 having an inlet port 52 connected to a fuel source 11, an outlet port 53, and a return port 54 connected with a fuel charge forming apparatus 14 for receiving excess fuel therefrom, a spool 61 movable in the body 51 and having means 72 for throttling flow between the return and outlet ports 54, 53, a pressure regulator controlling flow from the return port 54 to a control chamber 66 in communication with the spool 51 from whence it is exhausted to the outlet port 53 through a restriction 68. The pressure regulator is formed by a diaphragm 76 biased by a spring 79 to co-operate with a port 77. In use, fuel from the outlet port 53 is fed by a pump 13 to a tube 27 extending across an air supply passage 24 and having an opening 31 facing upstream of the passage, and excess fuel is returned thence to the return port 54. At equilibrium the diaphragm 76 takes up a position so that flow through the port 77 is equal to that through the restriction 68; the spool 51 is stationary and excess fuel is returned to the outlet port past the throttle means 72. When more fuel is drawn from the opening 31 so that the pressure at port 54 falls, the diaphragm 76 moves to reduce the flow through the port 77, so that the pressure in the control chamber 66 falls, and the spool 51 moves to reduce the flow past throttle means 72; thus the pressure in port 54 rises and this acts on the diaphragm to increase the flow through the port 77 until it is again equal to that through the restriction 68 and a new equilibrium position of the spool 51 is established. Likewise if the amount of fuel returning from the chargeforming means 14 increases the spool is moved to increase the flow past throttle means 72. The spring 79 has a low rate so that the force biasing the diaphragm 76 against the port 77 is substantially independent of diaphragm position. This force serves to determine the pressure in the control chamber 66 at equilibrium and ultimately to determine the fuel/air ratio of the charge formed in the means 14; this force may be pre-set by means of screw 82. Alternatively, Fig. 3 (not shown), the force on the diaphragm 76 may be adjusted continuously by a coil (84) in response to parameters such as engine temperature, oxygen content of exhaust gases, or atmospheric pressure.