Patent GB-640043-A (GB)
Title: Improvements in or relating to boost regulators for internal combustion engines
IPC: F02D9/00
Filed: 1947-10-24
Abstract: 640,043. Regulating. BENDIX AVIATION CORPORATION. Oct. 24, 1947, No. 28525. Convention date, Nov. 15, 1946. [Class 7(vi)] [Also in Group XXIX]. In a boost regulator for an internalcombustion engine in which the throttle valve is actuated by a servo-motor responsive to engine intake pressure and the datum is set manually, means connected to the manual control device is provided to release the servo valve should the latter become stuck in the intake pressure increase position. As applied to an aircraft engine, the manifold induction pressure is applied to the inside of the upper portion 76 of a compound bellows, the lower portion 75 thereof being evacuated so as to be responsive to atmospheric presure. The common boundary plate 79 of the bellows actuates the servo control valve 37 through a resilient link 83 and a floating lever 48. The servo power device 36 actuates the throttle valve (not shown) through a link 74, lever 68, shaft 34, lever 31, and link 30. Co-axial but not rigid with the shaft 34 is a further shaft 32 carrying an arm 29 connected to the pilot's control lever. Actuation of the latter to set the datum of the boost regulator rotates a cam 41 which acts on a spring-loaded lever 43 pivoted at 46 and connected to the servo valve through the intermediary of lever 48. A stop 106 prevents over-travel of shaft 32. For the higher intake pressure settings, a cam 109 on the shaft closes a micro-switch 23 whereby a valve is opened to allow antidetonant fluid to be supplied to the engine. Parallel with shafts 32, 34 is a further shaft 39 carrying arms 53, 62 which are rigid with the shaft and arms 54, 63 which are loose thereon, and any arm will move its complementary arm when the loose arm and a set screw 56 or 69 carried by two of the arms come into contact. Arm 62 is connected to the intermediate part of a floating lever 65 of which the ends are connected by links 66, 67 to shafts 32, 34 respectively. Loose arm 54 carries a spring-pressed stirrup 60 enclosing a projection 61 on the shaft of servo-valve 37. Arm 63 is connected through a link 71 to a spring-pressed plunger 38 subject to the pressure of the servo-motor motive-fluid supply. Should the motive-fluid supply fail, an abutment 102, which is normally kept depressed by the pressure of this supply acting through a passage-way 105, will rise and push servovalve 37 upwards so that the lower end of the power device will be vented and the liquid lock thereon will be removed. At the same time, piston 38 will be depressed by its spring and arm 63 will contact and force arm 62 against a stop 99. The pivoting point between arm 62 and lever 65 will thus become a fixed fulcrum and movements of manual control lever 29 will be communicated directly to the throttle shaft 34. If the pressure selected is sufficiently low to cause the servo-piston 36 to try to drive the throttle valve past a pre-determined minimum position, the automatic control is removed by the falling intake pressure collapsing bellows 76 until the centre plate 79 comes up against an adjustable stop 81. When this happens, the bellows will be unable to re-centre valve 37 from its raised position and piston 36 will act through link 67, floating lever 65, arm 62, shaft 39, and lever 54, to lower stirrup 60 and so re-set valve 37. Subsequent movement of the manual control to obtain a smaller throttle opening, acts in a manual control range as the movement of lever 29 will be communicated to the servo-valve through a lever 50, link 66, arm 62, arm 54, and stirrup 60. Should the servo-valve become stuck in the down i.e. pressure-increase position, the servo piston will rise to its top position and hold the throttle wide open. On rotation of manual lever 29 to the full pressure decrease position, arm 53 will be moved through arm 50, link 66, lever 65, and arm 62 in a counter-clockwise direction, away from arm 54, and the spring-loading 59 to hook 60 will be freed to allow the hook to release valve 37.