GB709076A - Anti-reversal device for internal combustion engines - Google Patents

Abstract

709,076. Engine stop-gear. C.A.V., Ltd. Oct. 14, 1952 [Oct. 26, 1951]. No. 25062/51. Class 122(4) A safety device for internal combustion engines of the compression-ignition type to which liquid fuel is supplied by a pump controlled by a governor responsive tc pressure variations in the engine air intake manifold comprises a valve adapted to control the communication between the manifold and the governor and to reverse the normal action of the governor to thereby interrupt the fuel supply and stop the engine when reversal of pressure condition occurs in the manifold. The output of an engine fuel pump g is controlled by a rack f actuated by a spring-loaded diaphragm d dividing a governor chamber a into two compartments b and c normally connected to the engine air intake manifold q and the atmosphere respectively Interposed between the manifold and the governor is a valve comprising an axially bored stepped piston k loaded by a spring m and having its larger and smaller diameter portions slidable in coaxial cylinders i and j respectively. The cylinder i is connected at one end to the atmosphere through a passage t and a filter u and at the other end to a venturi throat p in the manifold q by a pipe o and has a port r normally connected via by a pipe s to the compartment c. The cylinder j is normally connected by a port v and a pipe w with the compartment b. During normal running the piston k occupies the position shown in Fig. 1 and the governor operates in the normal manner being connected to the manifold through the bore in the piston k and the port v and to the atmosphere through the port r and the passage t. If accidental reversal of direction of engine rotation occurs with consequent reversal of the pressure condition in the manifold q, the positive pressure acts on the larger end of the piston k and moves it to the right against the action of spring m and causes the governor compartment b to communicate with the atmosphere and the compartment c to communicate with the manifold. In this condition the diaphragm d moves the rack f to a position in which the fuel supply is interrupted and the engine stops.