Patent GB-802710-A (GB)
Title: Internal combustion engine governor control
IPC: F02D1/00
Filed: 1956-08-20
Abstract: 802,710. Regulating. CATERPILLAR TRACTOR CO. Aug. 20, 1956 [Aug. 30, 1955], No. 25346/56. Class 7(6) [Also in Groups XXVI and XXIX] In an engine driving an output shaft through a hydraulic torque converter, the action of the normal engine-driven governor 10, Fig. 1, controlling the injection pump control rod 21 is overridden by a second governor 49, driven from the output shaft, when the speed of the output shaft drops below a predetermined value. The main governor 10 has a main spring 27 acting on a flange 16a of the governor sleeve 16 on which is slidably mounted a collar 16b loaded by a secondary spring 26 and connected through links 17, 20, to the control rod 21. The second governor 49 actuates through a lever 50 a rod 52 loaded initially by a spring 59 and, after a predetermined movement towards the right, by a second spring 61 abutted against a flanged sleeve 63. The rod 52 rotates through a rack and pinnion 88, 87, a cam 79 which moves a rod 75 attacher to the control valve 72 of a fluid pressure servomotor 71 the plunger 73 of which is normally out of contact with the end 99 of the control rod 21 but which under overspeed or very low speed conditions of the output shaft moves the rod 21 towards the shut-down position; During this overriding action the movement of the links 17, 20 is absorbed by the lost-motion spring 26 which permits movement of the collar 16b relative to the governor sleeve 16. Under normal running conditions the rod 52 is in the position shown in Fig. 1 in which it has moved to the right against spring 59 into contact with sleeve 63. If the speed of the output shaft rises above a predetermined value, the governor 49 overcomes the spring 61 and rod 52 moves further to the right, rotating the cam 79 anticlockwise which forces rod 75 to the right, causing the servomotor 71 to more rod 21 to reduce the fuel supply. Alternatively if, due to a sudden increase in load, the speed of the output shaft drops below a predetermined value, the rod 52 is moved from its normal position, Fig. 1, to the left by spring 59, rotating cam 79 clockwise whereby rod 75 is again moved to the right to cause a reduction in fuel supply. The cam 79 may be rendered inoperative by a stop inserted through a hole in its surrounding casing to engage a hole 115 in a member 105 carried by the cam; alternatively the stop may be positioned in holes 110 or 112 to prevent rotation of the cam in one or other direction to render either the overspeed or the low-speed action inoperative. In a modification, Fig. 6, the servomotor valve is connected to a rod 74' which co-operates with an arm 121 attached to the rod 52<SP>1</SP> actuated by the governor 49. The rod 52<SP>1</SP> is attached to a spring-loaded plunger 123 loaded by a weak spring 136 and sliding in a sleeve 125 abutting against a collar 128 loaded by a strong spring 127. Under overspeed conditions of the output shaft the governor 49 overcomes the spring 127 and the end 132 of arm 121 moves the rod 74<SP>1</SP> to cause the servomotor to override the main governor 10 and reduce the fuel supply. When the output shaft speed drops to a low value, the spring 136 moves plunger 123 to the left out of sleeve 125 and a projection 134 of the arm 121 contacts a peg 135 on a pivoted arm 119 which is thereby rotated to move rod 74<SP>1</SP> to the right, causing overriding of the main governor.