Patent GB-628471-A (GB)
Title: Control mechanism for internal combustion engines
IPC: F02D9/00
Filed: 1946-07-11
Abstract: 628,471. Fluid-pressure servomotor-control systems. BENDIX AVIATION CORPORATION. July 11, 1946, No. 20795. Convention date, Aug. 31, 1945. Addition to 628,469. [Class 135] In the automatic boost control mechanism according to the parent Specification, means are provided for limiting the range of adjustment of the datum varying control members and further means responsive to an engine operating condition, such as water injection, are provided for selectively placing the first means into and out of operative relation with the datum varying control members. Figs. 4 and 6 shows a lever or frame 42 pivoted on a shaft 43 and connected by a rod 48 to a floating lever 50 which is also connected to a manifold pressure responsive bellows assembly 53 and to a servomotor 65 controlling the throttle 19 of an internal combustion engine as in the parent Specification. The frame 42 carries adjustable tapped screws 95, 96, adapted to contact the ends of cam follower arms 85, 86, also pivoted on the shaft 43. The arms 85, 86 carry followers 39, 40 adapted to be engaged by cams 33, 34 on a shaft 32 adjusted by the pilot's lever 1 as in the parent Specification. A spring 44 tends to press the frame 42 in an anti-clockwise direction against the greater pressure exerted by spring fingers 98, 99, forming part of a fixed plate 101 and bearing on the cam-follower arms 85, 86. Both cam followers engage their respective cams but the position of the frame 42 is governed by one of them depending upon the adjustment of the screws 95, 96 and the amount of cam rise, the lowest rise corresponding to the highest pressure selection. The cam 33 which corresponds to the higher pressure selection may be rendered inoperative by disengaging its follower arm 85 by a rod 130 operated by a piston 131 which is moved by fluid pressure to the disengaging position when the variable speed gear or the hydraulic coupling between the engine and the supercharger is in the highspeed position. The mechanism for doing this is the same as that described in the parent Specification and may be controlled by the pilot or by a bellows responsive to barometric pressure. Thus the higher pressure selection range is operative at the lower blower speed and the lower pressure selection range at the higher speed. The shaft 43 however carries a further arm 109 pressed clockwise by a spring 113 against a rod 117 operated by a piston 118. The arm 109 has a horizontal extension or plate 110 with adjustable tappet screws 111, 112 adapted to contact the cam-follower arms 85, 86 respectively. Thus, each cam follower is prevented at a certain point from following its respective cam as the cam rise decreases and therefore as the selected pressure increases. These limits are individually adjustable by the screws 111, 112. Normally these limits are imposed, but if the engine is operating under water injection or with any other supplemental fluid system the pressure supply to the piston 118 is cut-off and the arm 109 retracted by the spring 113 so that each follower arm 85, 86 is permitted the full anti-clockwise movement and the pressure selection limits may be exceeded under either pressure selection programme. The water injection system and its control of the fluid pressure on the piston 118 is similar to that described in the parent Specification. Specification 603,157 is referred to.