Patent GB-1451265-A (GB)
Title: Power trains
IPC: F02C6/20
Filed: 1974-07-11
Abstract: 1451265 Hydrodynamic transmission control GENERAL MOTORS CORP 11 July 1974 [30 Aug 1973] 30704/74 Heading F2W In a hydrodynamic torque converter transmission the power absorbing capacity of the converter 12 is varied in dependence on the position of a throttle control 63 for the fuel feed to an engine 11 (shown as a single shaft gas turbine) and also is varied as a function of the speed of the converter input shaft 34 (driven from the engine output shaft 17 through gearing) so that the power capacity of the converter will always equal or be less than the engine output power. The variation is effected by varying the angle of the torque converter stator blades 44 through rotation of a shaft 53 by the arrangement illustrated in Fig. 4. In Fig. 4 an input driven pump 76 supplies fluid at a pressure regulated by a valve 81 to a governor 88 which has, as its output, input speed dependent pressure. The pump 76 also supplies pressure to a variable throttle 101, 102 whose valve member 101 is moved by throttle control 63 to vary the pressure in the chamber 172 of a spring 182 biased servo 157. In series with servo 157, and connected to its piston-rod 181 is a further spring biased servo 158 which receives pressure from the governor 88 via a speed signal control 116 in the form of a variable throttle 134, 136 and a spring biased servo which varies the throttle opening on dependence on the governor output pressure. The two servos 157, 158 move together to rock a lever 213 and vary the vane angle through a servo 216 which rotates shaft 53 through lever 222. In operation initial movement from the closed position to an intermediate position of the throttle control 63 does not directly control the engine fuel supply, which is determined by a bell-crank control 108 having a lost-motion connection 106 with the lever 63, and which maintains the engine at a governed idling speed, but opens throttle 101, 102 to supply the servo 157 with pressure, which causes the vanes 44 to be opened from a closed position to increase the demand from the converter and so increase the engine power, determined by the governor to keep the engine at idling speed. Further movement of throttle control 63 acts on bellcrank 108 to increase engine speed which causes pressure to be supplied to chamber 199 of servo 158 to further increase the power capacity of the converter to equal, or be just less than the engine output. For maximum acceleration the throttle lever is moved to its full throttle position which actuates a switch 228 to open two solenoid valves 187 and 208, valve 187 causing pressure from the pump 76 to be supplied direct to servo 156, and valve 208 venting chamber 199 of servo 158 so that the vanes 44 of the converter are kept at an intermediate position and the engine, whose power output is greater than the torque converter capacity, speeds up to its rated speed (controlled automatically by the fuel control) at which point governor pressure operates a switch 231, 227 to close the solenoid valves 187, 208 and permit the speed responsive pressure to act in chamber 199 of servo 158 and immediately cause vanes 44 to assume their position of maximum converter power capacity. As shown in Fig. 4 the pump 76 also supplies filling fluid for the converter. A transmission 37 may be connected in series with the converter 12 and may comprise a multi-ratio, a friction or a hydrostatic transmission, with automatic or manual control. The drive may be mounted on a vehicle. A one-way clutch 50 allows the converter turbine 43 to drive the engine 11 for braking the vehicle.