Patent GB-798616-A (GB)
Title: Improvements in internal combustion engine carburettors including an auxiliary device for starting and running said engines in the cold state
Inventor: MENNESSON ANDRE LOUIS
IPC: F02M1/04
Filed: 1956-10-29
Abstract: 798,616. Carburetters. SOC. INDUSTRIELLE DE BREVETS ET D'ETUDES. S.I.B.E. Oct. 29, 1956 [Oct. 31, 1955], No. 32951/56 Class 7(3) In a carburetter including an auxiliary device with a distributing valve for forming and supplying in the induction passage downstream of the throttle valve a rich mixture constituted on the one hand by fuel possibly emulsified in advance with air and on the other hand by additional starting air, the carburetter further including a movable part responsive to variations of the suction existing in the passage downstream of the throttle valve and capable of reducing the richness of the mixture when the engine is gathering speed after it has been started, this part is arranged in such manner that it varies simultaneously and inversely the respective flow passages for air and fuel supplied by the auxiliary device independently of the position of the distributing valve. When the engine is stopped and in the cold state the distributing valve 9 and the piston 33 occupy the position of Fig. 3. If the driver then operates the starter of the engine the suction which is produced in the passage 2 downstream of the throttle valve is transmitted through the conduit 8 and the distributing valve to the recess 32. This suction is then too low to overcome the resistance of the spring 35 and the piston remains applied against its abutment 39 thus stopping the air inlet conduit 7. The suction is also transmitted fully through the conduit 36, orifice 21 and groove 25 to the fuel inlet orifice 18 and there is a considerable inflow of emulsified fuel towards the induction passage. On starting as the engine gathers speed the suction acting on the piston 33 quickly increases and this piston is pulled on to the packing joint 41. The air inlet conduit 7 is then opened and air is sucked towards the conduit 8. At the same time the fuel in compelled to pass through the calibrated orifice 37. If after the engine has been started and when it is still cold the suction transmitted through the conduit 8 stops merely by the fact that the engine stops piston 33 comes back to its initial position shown in Figs. 2 and 3 since rod 44, 44a is held in upward position by lever 45. On the contrary, if the suction is reduced to zero as a result of the opening of the throttle valve the lever 45 is lowered and enables spring 46 downwardly to drive rod 44, 44a the arm 44a of which then acts upon piston 33 and the piston is kept in its lowermost position if the throttle 4 is sufficiently opened. With the engine started and cold the throttle valve 4 being not opened as the temperature of the engine rises the distributing valve 9 rotates in the clockwise direction which has for its effect to reduce the air and fuel flow. In an intermediate position the communication between groove 25 and orifice 21 may be cut off but the flow of fuel remains possible through calibrated passage 26 and groove 24. When the distributing valve is nearing its position where it is out of action the flow rates of fuel and air both depend upon the suction existing in grove 24 and the richness of the fuel air mixture that is supplied then remains constant whereas its flow rate decreases. Orifice 21 which might be replaced by a series of calibrated holes has chiefly for its object to determine in accordance with the ambient temperature the richness of the mixture when starting proper takes place, this richness being higher as the temperature is lower When the engine has reached its working temperature the distributing valve occupies a position, Fig. 6, for which it does not give any supply. Means operatively connected with the distributing valve may be provided for cutting off the action of auction on the piston 33 when the auxiliary device is out of action and for restoring this action when the auxiliary device is again brought into action. The displacement of the piston 33 towards its abutment 39 may be limited by making the abutment 47 of suitable dimensions. The opening of the piston 33 may be limited to one third of one fourth or one half of its total stroke. The piston 33 may be replaced by a diaphragm carrying a pair of plates and in this case the calibrated orifice 37 would be provided in the seat of the lower plate which controls communication between the conduits 34, 36. The distributing valve may be operated manually.