Patent GB-716484-A (GB)
Title: Improvements in auxiliary starting carburetters
IPC: F02M1/04
Filed: 1950-12-04
Abstract: 716,484. Carburetters. SOLEX. Dec. 4, 1950 [Dec. 3, 1949], No. 29664/50. Class 7(3) In a carburetter comprising a throttle valve and an auxiliary starting carburetter constituting a single source of rich mixture for the starting and running when cold of an internal-combustion engine, this rich mixture is controlled by a distributer valve permitting according to its position and also to the position of the throttle valve the discharge of the mixture either upstream or downstream or simultaneously upstream and downstream of the throttle valve the rich mixture if any delivered downstream of the throttle valve being always diluted by additional air comparatively to that delivered upstream. In Fig. 1 an auxiliary starting carburetter comprises a fuel well 10 from which fuel is drawn through a channel 15 into a chamber 16 and from the chamber together with air which enters through a tube 24 passes into the induction pipe 1 on the downstream side of a throttle valve 4 therein. A rotatable shut-off valve 17 is provided. In operation when the engine is being driven by the starter this valve occupies the position of Fig. 2A and the fuel from the channel 15 passes to the chamber 16 through a relatively large orifice 20. When the engine is running and is beginning to gather speed the operator brings the valve 17 into the position of Fig. 2B. In this position the channel 15 is connected to the chamber 16 through an orifice 20a and at the same time a groove 27 provided in the valve 17 connects the channel 15 to a second channel 25 leading to a Venturi 2. When the throttle is in its closed or idling position there is practically no suction on its upstream side and a supplementary air inflow takes place through this channel. When the throttle is opened to speed up the engine the suction on the downstream side of the throttle decreases and reduces the flow through conduit 22 but the suction in the Venturi 2 increases and causes a certain amount of fuel diverted from that supplied through channel 15 to flow to the induction pipe through channel 25. In the position of the valve of Fig. 2C the auxiliary carburetter is out of action. One or several orifices 21 in the valve 17 control the supply of mixture into the conduit 22. In a modification channel 25 leads to the face of the body part against which the valve 17 works. The channel is provided with a non-return valve. Fig. 4A shows the valve 17 employed in the position in which the starting carburetter is brought in. Orifice 20 connects channel 15 to chamber 16 and groove 27 connects channel 25 to the channel 15. The non- return valve prevents when the throttle 4 is in the idling position air coming from the channel 25 from penetrating into chamber 16 and thus reducing suction in the channel 15. By turning the valve anti-clockwise the flow is first restricted and then cut off. Fig. 5 shows a modification comprising a valve 29 operated by the throttle valve. In the position shown this valve connects conduits 30, 31 and thus connects the channel 15 which is connected to conduit 31 by valve 17, Fig. 7A, to the conduit 22 leading to the downstream side of the throttle valve. When the throttle valve is fully opened the valve 29 directly interconnects conduits 31 and 32 to enable fuel from the well 10 to flow towards the Venturi 2. In intermediate positions of the throttle valve conduit 31 communicates through valve 29 with conduits 30 and 32. A non-return valve may be provided at the outlet of air intake 24 into chamber 16.