GB747534A - Improvements in two-stroke internal combustion engines - Google Patents

Abstract

747,534. Spray carburetters: regulating; auxiliary air admission; timing ignition. SOLEX. May 5, 1954 [June 17, 1953], No. 13140/54. Classes 7(2), 7(3), 7(4) and 7(6) A two-stroke crankcase compression engine comprises means responsive to the variations of the maximum or minimum pressure occurring in the crankcase on each cycle for controlling means influencing the operation of the engine. In Fig. 1 the pressure in the crankcase is transmitted through a pipe 20 containing a non-return ball valve 21 to a chamber 18 containing a spring-loaded diaphragm 17 attached to a needle valve 16 controlling a supplementary fuel jet 15 in a carburetter 10 supplying fuel-air mixture through a pipe 9 to the crankcase. On the first down-stroke of the piston 2 the pressure in chamber 18 rises to the maximum crankcase pressure and is maintained at this pressure throughout the remainder of the cycle by closing of the ball valve 21. On subsequent strokes the valve 21 is only opened if the maximum crankcase pressure exceeds the pressure in the chamber 18 so that the pressure in chamber 18 varies with variations in the maximum pressure on each cycle in the crankcase and operates the diaphragm 17 to vary the richness of the fuel-air mixture. A bleed orifice 22 permits a, gradual reduction in the pressure in chamber 18 if the value of the maximum crankcase pressure decreases. In a modification the diaphragm 17 is responsive to the minimum pressure in the crankcase on each cycle. In a further modification, Fig. 2, the diaphragm 17 controls a valve 23 in an auxiliary air intake passage 24 leading into the induction pipe 9 and in another modification the diaphragm 17 actuates an ignition timing device. In a fuel injection engine the pressure-responsive device may control the quantity of fuel injected or the time of injection.