Patent GB-233216-A (GB)
Title: Improvements in or relating to carburettors for internal combustion engines
IPC: F02M1/00
Filed: 1924-01-31
Abstract: 233,216. Stromberg Motor Devices Co., and Mock, F. C. Jan. 31, 1924. Spray carburettors.-The idling or by-pass nozzle is so connected with the main nozzle as to provide an air supply for the latter when the idling nozzle is inoperative, the main nozzle carrying and being surrounded by an accelerating well having a laterally - extending arm carrying an upwardly extending tube providing an additional air inlet for the main nozzle. 'The nozzle is of large diameter, has a narrow flange below a conical top and is located in a Venturi tube the diverging portion of which has two different tapers. The carburettor casing comprises a lower part 23 and an upper 24 joining along the line 25 which is above the normal fuel level x-x. Two carburetting-chambers 27 extend through the casing, each chamber having a throttle valve 31, a main fuel nozzle 29 and a Venturi tube 28 the upper or diverging portion of which is of two different tapers y, z, Fig. 5. A float chamber 33, Fig. 3, substantially surrounds the two chambers and comprises two parts 34, 35 connected by a tube 36 on the longitudinal axis of the carburettor, each part containing a float 37 attached to arms 38 of a yoke 39 as described in Specification 233,580. The yoke is pivoted on pins 44 and carries a pin 43 over which is hooked the fuel control valve 42. Fuel entering at 57, Fig. 3, reaches this valve through a conduit 47 after passing through a gauze filter 48 and tube 58. From the float chamber fuel passes to each of the nozzles through separate ducts 61, Fig. 3, which lead to bores 62, Fig. 5, each containing a plug 64 with calibrated orifice 66. Hence the fuel passes to a chamber 67, Figs. 2 and 5, at the base of the nozzle which is supported on the arms 72. A plug 69 in the chamber 67 is bored at 82, 83 and screws into an upper part 71 over which is again screwed a part 75 so as to leave a well 76 which communicates through an arm 78, 79 and apertured plug 81 with the carburettor air inlet. Air reaches the fuel stream through apertures 77 and the aerated fuel is discharged through outlets 87 in a conical head 88 provided with a small flange 86 which prevents fuel from being drawn in drops into the eddy space above the nozzle. The bores 83 in plug 69 open into an annular space which communicates through a passage 85, Fig. 5, and calibrated orifice 91 with the idling nozzle 109 which is fed with aerated fuel through a tube 92 and passage 102, the tube 92 being surrounded by a chamber 93 to which air is admitted through a calibrated axial bore 97 and lateral bores in an interchangeable plug 94. This air is taken from an annular space 96 around the Venturi tubes, which space is in communication through ports 98, Fig. 4, with a lower annular space 99 opening into the air intake through a slot 101. The idling nozzle 109 is eccentrically mounted in a rotatable plug 104, Figs. 4 and 7, so that by adjustment of the plug, the position of the nozzle relative to the throttle valve edge may be varied as described in Specification 233,217. When the idling system is out of action at wide open throttle positions, it serves to supply air to the fuel at a relatively high point in the main nozzle so as to reduce the gravity head which, in addition to the suction head, determines the fuel flow. The height to which the ducts 83 deliver this air can be varied by altering the plug 69. By closing the passages 98, 99, Fig. 4, and providing a port 100 leading to the Venturi tube, the suction in the space 96 can be raised.