Patent GB-407925-A (GB)
Title: A method of and a system for controlling the supply of liquid fuel to an internal combustion engine
IPC: F02D9/00
Filed: 1932-06-21
Abstract: 407,925. Spray carburetters; pumps. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. June 21, 1932, No. 17528. Convention date, June 22, 1931. [Classes 7 (iii) and 7 (vi).] The fuel delivered by a pump to the air charge of an internal-combustion engine externally of the cylinders is controlled by varying the output from the pump by means of the pressures anterior and posterior to the throttle in the air conduit, so that an increase either in the air pressure anterior to the throttle or in the air pressure posterior to the throttle tends to cause an increase in the delivery of fuel. In the construction shown in Fig. 1, the stroke of a pump 21 is controlled in accordance with the pressure anterior to the throttle 11, and in accordance with the difference of pressures anterior and posterior to the throttle valve 11. The pressure in the mixing chamber 2 is transmitted through a pipe 95 to one side of a flexible diaphragm 93, which closes a chamber 91, and the other side of the diaphragm is exposed to atmospheric pressure. The diaphragm transmits its movement to one arm 51 of a three-arm lever 51, 53, 55, of which the arm 53 engages a groove 87 provided in a tensioned barometric device 73 responsive to changes of altitude, Which is enclosed in a casing 47 open to the atmosphere through an aperture 89. The arm 55 transmits the combined movement of the barometric device 73 and of the diaphragm 93, through levers 71, 35 to a forked lever 39 which shifts a variable throw cam 31 axially. The height of the cam varies the stroke of pump plungers 27 which are actuated by bellcranks 29, and which deliver the fuel to a nozzle 25 in the manifold 2 at the outlet of which a rotarv distributer 12 be housed. To enrich the mixture at low altitudes, the lever 55 carries a floating lever 57, having a toe 61, which is normally forced by a spring 65 into engagement with a recess 63 in the lever 55 and, when the lever 55 approaches its uppermost position, a projection 69 on the lever 57 contacts with the casing 47, further movement of the lever 55 tilting the lever 57 to magnify the movement of the lever 71 and increase the amount of fuel delivered by the pump. An adjustable stop-screw 43 on the lever 35 determines the minimum amount of fuel delivered. To delay the movement of the air throttle 11 with respect to the movement of its control rod 13, the throttle valve spindle carries an arm 265, which is pressed by a spring 273 against a stop 269 and, in addition, an arm 295 on the spindle is connected to a plunger 291 operating in a dashpot 289. In a modified construction, the casing 47 and the chamber 91 are in communication, so that the stroke of the fuel pump is controlled in accordance with the pressure in a chamber communicating with the main air conduit both anterior and posterior to the throttle, and in accordance with the difference between said pressure and the external air pressure. In a third modification, Fig. 5, in which the air is supplied to the pipe 9 by a supercharger, the pressure between the supercharger and the throttle valve is transmitted through a pipe 129 to a casing 105, which contains a tensioned barometric device 107, and also to one side of a diaphragm 117, the other side of which is subjected to the pressure in the air conduit between the throttle and the engine through a pipe 131. The diaphragm and the barometric device control the stroke of the fuel pump through a lever 111 which acts on a lever 115 connected to the pump-actuating lever 35. In the modification shown in Fig. 2, the fuel delivery from the pump is controlled in accordance with the pressure in a chamber communicating with the main air conduit both anterior and posterior to the throttle, and in accordance with the position of the air throttle valve. A cam 143 on the air throttle shaft 145 engages a roller 142 carried by a lever 139 urged upwards by a spring 141 and having a cam surface 147 which engages a roller 149 carried by the lever 133 which shifts the fuel-pump cam 31. The lever 133 is also moved through a lever 155 by a tensioned aneroid 153 in a casing 135 which is open to the atmosphere through an orifice 165 ; the aneroid is also subjected to the pressure in the air conduit 2 through a pipe 167. The various fuel controls above described instead of controlling the stroke of the pump plungers may adjust a metering valve in the pump outlet, as shown in Fig. 3, in which a pump 171 supplies fuel continuously to a chamber 183 in a casing 179 which is divided into two chambers 183, 185 by a diaphragm 181 ; excess fuel is returned to the pump inlet 187 through a pipe 195 which is controlled by a spring-loaded valve 199 carried by the diaphragm. The fuel flows under a small pressure difference from the chamber 183 past the metering valve 211 to the chamber 185 and is delivered through a pipe 191 to a nozzle 173. To control the fuel supply in accordance with the setting of the air throttle valve 11, a cam 213 acts on a roller 215 carried by a lever 217 which, through a lever 221, acts on one arm of a lever 239, 237, the other arm moving the valve 211. The valve is also controlled through levers 227, 231 and 247 by a tensioned aneroid element 223, enclosed in a casing 225. The lever 247 carries the pivot 241 of the lever 239, 237. The aneroid is subjected to the combination of altitude and manifold pressures by a pipe 253 which is connected to the manifold at 97 and a pipe 255 connected at 259 to the pipe 9 before the throttle valve 11, and the air may be delivered to the pipe 9 by a supercharger. The pipe 253 may contain a perforated plug 261. The Specification as open to inspection under Sect. 91 states also that the aneroid devices, 'shown in Figs. 2 and 3, need not be exposed to manifold pressure, the fuel delivery being controlled in accordance with the air pressure anterior to the throttle and by the position of the air throttle. This subject-matter does not appear in the Specification as accepted.