Patent GB-858681-A (GB)
Title: Improvements in or relating to a fuel supply system for an internal combustion engine
IPC: F02D9/00
Filed: 1958-03-10
Abstract: 858,681. Charge forming apparatus ; regulating. BORG-WARNER CORPORATION. March 10, 1958 [March 12, 1957; March 13, 1957]. No. 7700/58. Classes 7(3) and 7(6). [Also in Groups XXVIII and XXXV] A fuel supply apparatus for an internal combustion engine comprises an air intake conduit connected to the cylinders of the engine, a fuel delivery pump drivable by the engine, a plurality of nozzles respectively positioned adjacent the cylinders and connected with the fuel delivery pump to be supplied with fuel therefrom, mechanism for starting the internal combustion engine and ar auxiliary fuel supply means for supplying ar air-fuel mixture into the air inlet conduit anc thereby to the engine cylinders, the auxiliary fuel supply means being operable by the engine starting mechanism to be renderec effective thereby. In operation, the vacuun motor 121 is responsive to the speed o operation of the vehicle engine particularly due to the orifices 152 and 153 in the throttle valve assembly 144. The passage 149 in the throttle valve shaft 146 is connected with tht chamber 162 and thereby with the motor 121 Due to the orifices 152 and 153 in the throttle fly assembly 144, the pressure in the chamber 162 varies with the speed of the vehicle engine and with the mass of air that passes througl the passage 141. The orifices 152 and 15: co-operate in order to provide this variatior of pressure in the chamber 162 as follows The orifice 153, being on the lower face of the plate 145 is always subject to pure manifolc pressure. When the plate 145 is closed, the orifice 152 is subject only to atmospheric pressure existing below the air cleaner 142 Since manifold pressure is less than atmospheric pressure, air flows through the orifice 152, the passage 148 and the orifice 153 intc the manifold 143. The pressure existing in the passage 148 is thus intermediate between these two pressures and is transmitted withou change through the orifice 150 and the passage 149 to the chamber 162 and thereby to the motor 121. As the throttle assembly 144 is opened, the slanted end 151 becomes more parallel with the sides of the air passage 141 and becomes increasingly subject to manifold pressure instead of the atmospheric pressure existing above the plate 145. Thus, as the plate 145 is swung open, the flow through the orifice 152 and the orifice 153 gradually decreases, and the pressure in the passage 148 which is applied to the motor 121 thus gradually decreases from the intermediate pressure mentioned above to the manifold pressure. The pressure in the passage 148 thus varies inversely with the flow of air through the passage 141 and with the speed of the engine. Due to the fact that the orifice 152 is increasingly subject to manifold pressure as the plate 145 is rotated, it should be noted that the change in pressure in the passage 148 is quite smooth and gradual, and this pressure changes in accordance with engine speed until the plate 145 has reached approximately 35 degrees throttle opening from its engine idling position. The vacuum motor 126 being connected directly with the orifice 158 in the manifold 143 is thus subject to the manifold vacuum which varies directly with the load on the engine. Both the motor 121 subject to engine speed and the motor 126 subject to engine load vary the output per stroke of the plunger 25 as will be described. The position of the cam 100 in the grooves 106 and 109, that is, the vertical position of the cam 100 as seen in Fig. 8 determines to a large degree the positioning of the rotating valve pin 68 which causes a variation of the output of the plunger 25. The cam plate 100 has its position modified by the positions of the cam guides 103 and 107 which are respectively movable about the pins 105 and 108, as will be described. The motors 126 and 121 function to move the pin 68 in a clockwise direction for the purpose of increasing the rate of discharge of the plunger 25 per stroke when the load on the engine as evidenced by a change in manifold pressure increases or when the speed of the engine decreases. The pressure in the conduit 161 increases as the speed of the engine decreases. This increasing pressure is effective on the diaphragm 123 of the motor 121 causing the plunger 124 to swivel the cam guide 103 counterclockwise about the pin 105, and the guide 103 acting through the pin 102 moves the -cam 100 to the right, thus moving the pin 68 clockwise as seen in Figs. 2 and 8 and increasing the output from the plunger 25 per stroke to the nozzles 51. Conversely, as the air flow in the passage 141 and the engine speed increase, the pressure in the conduit 161 decreases, and the spring 118 is effective to move the cam 100 to the left so that the pin 68 moves oppositely and decreases the output of the plunger 25 per stroke. The manifold pressure is effective through the port 158 on the diaphragm 128 of the motor 126, and as the load increases, the manifold pressure increases moving the cam 100 upwardly through the rod 129 and the lever 111, the pins 101 and 102 moving in the grooves 106 and 109 of the guides 103 and 107. The control pin 68 moves along the slanted cam surface 115 and is moved thereby clockwise so as to increase the output from the plunger 25 to the nozzles 51. Conversely, as the load decreases, the manifold pressure as applied to the diaphragm 128 decreases, and the cam 100 is moved in the opposite direction, so that the pin 68 moves counterclockwise under the influence of the spring 118 effective on the lever 116 to decrease the output of the plunger 25 per stroke. It is preferable to cause an increase in the pressure in the chamber 162 and in the conduit 161 beyond that due to the throttle assembly 144 when the accelerator A is in a relatively relaxed position. The valve 164 co-operating with the orifices 159 and 160 functions for this purpose. The increase in pressure in the conduit 161 acts through the motor 121 to cause an increase in the output of the plunger 25, to take care of idling conditions of the engine which, as is well known, require a greater amount of fuel per revolution of the crank-shaft than at higher speed conditions. It is contemplated that the valve plunger 166 under all conditions shall open the orifice 159 to some extent. Since the orifice 160 is above the throttle plate 145 and the orifice 159 is below the plate 145, there is a flow of air from the orifice 160 to the orifice 159. This results in a pressure which is transmitted through the valve 164, when the latter is opened, that is slightly greater than the pressure that exists in the passage 149, so that the pressure in the chamber 162 is increased slightly from that due only to the throttle assembly 144, thus increasing the output of the plunger 25. The orifices 159 and 160 are effective only under idling conditions, for example, when the throttle plate is not opened more than 4 degrees from its idling position, due to the functioning of valve 164. The lever 173 and link 172 are so arranged that the slide 169 has its passage 170 aligned with the conduit 171 when the throttle plate 145 is opened less than 4 degrees, so that the pressure influence from the orifices 159 and 160 is effective on the pressure in the chamber 162 only below the 4 degrees opening of the throttle plate 145. Under the engine idling conditions, there is a small amount of air that passes around the edges of the plate 145 as well as through the orifices 152 and 153. In addition, air also flows from the orifice 160 to the orifice 159 and the exact amount of this air flow may be adjusted by adjusting the plunger 166. The adjustable valve plunger 166 has an influence on the change in the pressure in the chamber 162 due to the functioning of the orifices 160 and 159, and this is the principal reason for the adjustable valve 163. The fuel requirements for individual engines under idling conditions differ, and the specific amount of fuel supplied to any one individual engine can be exactly adjusted under idling conditions by adjusting the plunger 166. The idling r.p.m. of the engine under normal conditions is determined by the setting of the stop screw 157. The purpose of the tube 132 and the piston 133 therein is to momentarily increase the output by the plunger 25 when the accelerator A is depressed to accelerate the vehicle. On the opening of the throttle plate 145 caused by such a movement of the accelerator A, the manifold pressure as applied to the motor 126 suddenly increases and moves the lever 111 and the cam 100 upwardly as seen in Fig. 8 so that the slanted side 115 on the cam 100 moves the control pin 68 clockwise toward its rich position. This movement of the cam 100, however, is not sufficient under vehicle accelerating conditions; and, therefore, the piston 133 acting in the closed tube 132 acts through the bracket 137 to swing the guide 103 counterclockwise about its pin 105. This movement of the guide 103 also tends to move the cam 100 toward the right through the pin 102. The arm 110, under these conditions, contacts the guide 107 and functions to cause the guide 107 to move in the clockwise direction about its pin 108, and such movement of the guide 107 through the pin 101 causes additional movement to the right of the cam 100. Such movements of the guides 103 and 107 thus provide the additional movement toward rich position of the control pin 108 which is necessary. The arm 110 is provided so that the cam 100 will be moved substantially to the right for accelerating conditions whether the cam 100 is in a lowermost position as seen in Fig. 8 corresponding to light loads or is in an upper position corresponding to heavy loads for which loading the pins 101 and 102 individually are respectively more effective than the other. The piston 133 fits in the tube 132 loosely. This is so that air leaks past the piston, and eventually the piston 133 is of no effect on the cam guides 103 and 107 to increase the f