Patent GB-774744-A (GB)
Title: Internal combustion engine supercharger drive
Inventor: JOHNSON LLOYD EDWARD
IPC: F02D9/00
Filed: 1955-04-20
Abstract: 774,744. Charging pumps; regulating. CATERPILLAR TRACTOR CO. April 20, 1955, No. 11379/55. Classes 7 (2) and 7 (6). [Also in Groups XXIV and XXIX] The ratio of a variable speed gear in an I.C.-engine supercharger drive is varied by hydraulic means controlled automatically by the volume of fuel fed to the engine. A directdrive clutch 45 and overdrive brake 48 of a planet gear 27 between an engine-driven input shaft 23 and an output shaft 64 driving the supercharger supplying air to the engine, are engaged by selectively directing pressure oil 94 from the engine lubricating system, through a piston selector-valve 95 to either side of an axially-movable clutch-brake piston 55, the selector-valve being actuated to three positions, neutral, high and low, in response to varying fluid-pressure 65 acting on a diaphragm 93 and supplied by a regulator-valve 18, Fig. 3, set to provide three different pressures under the automatic control of an extension 78 of the usual manually- or speed-governed rack which simultaneously adjusts the injection pumps to meter the fuel feed to the engine. Supercharger drive-ratio thus varies automatically with fuel feed and hence load to ensure correct fuel-air ratio. The gear comprises an input planet-carrier 27, fast with a pinion 25 driven by the input shaft 23, intermeshed planets 33, 36, meshing respectively an output sun 34, fast with a worm-wheel 63 driving the supercharger shaft 64, and a reaction sun 37 fast on a shaft 38 carrying one set of discs of the direct-drive clutch 45 and overdrive brake 48, the other set of which are carried respectively by the input planet-carrier 27 and fixed flange 42. Pressure is supplied to the interior of the selector-valve 95 from the line 94 and a space between the double diaphragm 93. The clutch-brake piston 55 slides on fixed side-walls forming opposed centrifugally-balanced pressure-spaces 51, 54, which, in the neutral position shown, are both pressurized from the valve-port 98 and bleed externally through grooves 62 by-passing sealrings 60 to clear sludge. Restricted valve openings 97, 99 supply lubricating and cooling oil from the selector-valve 95, through ports 100, 101, to the clutch and brake. This neutral position is maintained by regulating pressure in the line 65 to an intermediate value. Regulating pressure 65 to a low value permits a spring 102 to overcome the diaphragm 93 and shift the selector-valve 95 to the right, pressurizing the space 54 and exhausting 51. The piston 55 is thereby moved left to engage the direct-drive clutch 45. Regulating the line 65 a high value shifts the selector-valve 95 left, pressurizing the space 51 to shift the piston 55 right and apply the overdrive brake 48. Regulator valve.-The three pressure steps are obtained from the regulator valve 18, Fig. 3, to which pressure from the common fuel feed pump is supplied at 71, to pass through a space 73 and slots 81 in a slidable sleeve 74, into a delivery chamber where it downwardly loads a diaphragm secured to the sleeve 74 and loaded upwardly by an adjustable spring 76. The delivery chamber 80 bleeds constantly through a restrictor 82, and feeds the line 65 leading to the selector-valve actuating diaphragm 93, Fig. 2. The level of the escape opening to the delivery chamber 80 provided by the slots 81 is controlled by the engine fuel-injection rack 78 turning a plug 77 having closure members 77a, b, c, operative at three different levels. Thus with the level 77a operative, the diaphragm 83 sets the sleeve 74 in an intermediate position, shown, in which delivery pressure 65 maintains the selector valve 95, Fig. 2, in neutral. When the rack turns the plug 77 to render level 77b effective, the diaphragm 83 rises to reduce delivery pressure 65 to its low level for direct-drive. When turned to render level 77c effective, the diaphragm 83 is depressed, increasing delivery pressure 65 to its high value for overdrive.