Patent GB-909371-A (GB)
Title: An engine fuel charging device
IPC: F02M1/00
Filed: 1958-12-15
Abstract: 909,371. Carburetting apparatus. GOODRIDGE, L. M., and MARTIN, C. L. Dec. 15, 1958, No. 40308/58. Class 7(3) Carburetting apparatus comprises a plurality of conduits each of which is adapted for connection at one end to the intake port of an engine, a throttle valve for the conduits, a source of fuel, a fuel nozzle extending into each conduit downstream of the throttle valve and connected to the source of fuel, metering orifices of like flow capacity between each nozzle and the source, outlets for each nozzle in each conduit and air passages extending from each nozzle outlet to a conduit upstream of the throttle to apply equal back pressures on the fuel in each nozzle so as to divide the flow equally between the nozzles. Fig. 1 is a schematic showing. The air intake stack A is connected directly to a fuel injector unit B only one of which is shown. A fuel injector unit B is provided for each intake port of the engine or each pair of intake ports and the intake stack A is connected separately to each fuel injection unit B by a branched manifold. Each fuel injection unit has a float bowl containing a float for operating a valve in the fuel supply connection for the bowl. In the air intake stack A is a manually controlled throttle valve F mounted on the shaft G. Below the throttle valve F is an unbalanced pressure responsive automatic valve H. The shaft supporting valve H is biased to closed position by either an eccentrically mounted weight or a coiled thermosensitive spring responsive to engine temperatures or both. The valve H will create between it and the throttle valve F a zone of modulated pressure in small degree higher than that at the fuel injector nozzle D except at normal engine operating temperatures with throttle F in the wide open range and at high engine speeds. The valve H has no effect when nearly wide open. Within this zone of modulated pressure created by valve H is a nozzle J which faces the air stream past throttle F. A port K connects with nozzle J and in turn with the sealed fuel bowl C by way of tube L. At small openings of the throttle F a stream of air is directed into port K to increase the pressure in tube L and in the fuel bowl. Larger degrees of throttle opening produce the same effect on nozzle J. Above throttle F and located opposite shaft G is a tube M arranged tangentially of the intake stack. An opening is provided in tube M for sensing the pressure in the air stream past the throttle. As throttle F is opened a Venturi is formed between the upper surface of valve F and the lower surface of tube M. When valve F is opened further this distance will increase and eventually the throat of the Venturi is formed by the tube M and the throttle shaft G. At closed throttle the pressure in tube M will be atmospheric or substantially so and air will flow through tube N to lift the fuel from nozzle D. The Venturi action between the throttle F and tube M will decrease the flow through the tube N as the throttle is opened. At top engine speeds at wide open throttle the fuel will be raised in the tube N. It is possible to have the tube M act as an auxiliary fuel nozzle if desired. The system schematically represented in Fig. 2 is a second system operating with positive pressures on the fuel in the nozzle. The unbalanced valve 2H is upstream of the throttle valve 2F. Fig. 3 schematically illustrates the pushpull arrangement which combines the systems of Fig. 1 and Fig. 2. This system can be adjusted so that the pressure connected to the vent controls fuel metering in one range of throttle openings and engine speeds and the pressure connected to the fuel injector operates in another range or both may be effective continuously. The bias on the valve 3H may be one which progressively decreases with valve opening in which case the pressure system on the injection nozzle would be the exclusive control at large throttle openings. On the other hand when nozzle 3M is merely a port to bleed atmospheric pressure and not a Venturi then the system can be adjusted by decreasing the metering of the suction bleeds connected to the vent on the fuel bowl to make the pressure system on the injector nozzle control the fuel during idle only. In a modification a suction operated piston may act upon the spring of the unbalanced valve. In the arrangement shown in Fig. 4 the pressure in the conduit 76 and acting on the fuel nozzle 77 is controlled by the throttle valve 36. Thus as the throttle opens more of the port 48 will be subject to the air sweeping about the edge of the throttle valve 36. Consequently the pressure in the conduit 47 will decrease until the throttle reaches about half way when approximately intake stack pressure will prevail within the conduit 47. In Fig. 5 each of the cylinders 2 is shown in dotted lines. Connected to the cylinders is a manifold 34 having a branch for each intake port. Centrally of the distribution chamber 34A is a stack 35 as described with respect to Fig. 4. Fig. 7 shows a modification in which the intake ports are grouped in pairs. Each float chamber is provided with twin air intake units 81 (Fig. 9). Two fuel nozzles 77 are supplied from a single fuel chamber. Various forms of injector unit are described. Fig. 20 shows a twin injector unit which can be used for two intake ports. The float bowl is shown in section at 142. In Fig. 27 a second intake stack has an unbalanced valve 301. A clamp 303 secures a bellcrank 304 on shaft 302 of valve 301. One arm 305 has an adjustable weight 306 positioned to bias the valve 301 to closed position. The other arm 307 mounts a roller 308 which rides on cam surface 309 of lever 310 clamped at 311 on the primary throttle shaft 237. During operation as throttle 236 is opened cam face 309 will disengage from roller 308 leaving throttle valve 301 free to open by the action of suction. After initial opening air stream velocity in stack will control the position of throttle 301.