Abstract: A process is proposed for controlling an automatic transmission wherein a transition occurs from a first, lower reduction step to a second, higher reduction step when a first clutch disengages and a second clutch engages and a synchronizer speed is calculated by multiplying the transmission output speed by the reduction ratio of the second reduction step. A speed value, at which the pressure increase of the second clutch begins, is assigned to the synchronizer speed from a characteristic curve. The characteristic curve is adapted if the transmission input speed exceeds the synchronizer speed or if the gradient of the transmission input speed exceeds a limit value.

Abstract: In an electronic-hydraulic control mechanism of an automatically shifting motorcar transmission, control valves (88, 70, 65, 67, 91 and 94) are coordinated with actuation devices (81 to 87) of hydraulically engageable and disengageable friction clutches or brakes (A to E1). The pressure level in one main pressure system of the control mechanism is regulated by a main pressure valve (29) while a control unit (72) designed as microprocessor controls the actuation devices via electrically actuated solenoid valves (41, 42 and 43) and pressure-control valves (38, 39 and 40) in accordance with operation parameters of the motorcar transmission and of a drive engine, the same as of a shift and/or travel program control.

Abstract: In a control mechanism for a frictionally engaged lock-up clutch of a hydrodynamic torque converter, a coupling element (8) is axially displaced for engaging and disengaging the lock-up clutch (7), face end actuation spaces (10, 11) being accordingly pressurized via regulating valves (15, 16). A lubricant line (28) leads via a radiator (39) to lubrication points (40) of a change-speed gear (6) rear-mounted on the torque converter (3), the lubricant line (28) being attached to a controlled return flow of the actuation space (11). To ensure there is a sufficient supply of lubricant to the lubrication points (40) and a sufficient cooling of the pressurized fluid or lubricant in all shift conditions of the lock-up clutch (7) via the radiator (39), a leg (34) of the main pressure line (13) is attached to the lubricant line (28) before the radiator (39) which feeds a missing amount of lubricant into the lubricant line (28).

Abstract: A device for electrohydraulic actuation of a clutch of a differential transmission (31) situated between an automatic transmission (3) and the drive wheels of the vehicle comprises an actuating piston (23) actuated by pressurized fluid supplied via a main contorl line (4) through a safety valve (6) and a clutch valve (13), a pressure reducing valve (5) is provided for supplying a reduced constant pressure fluid to a pilot control line (7) which is connected to both the safety valve (6) and the clutch valve (13), and a pressure control valve (11) is provided in the pilot contorl line (7) and, when the pressure control valve (11) is closed, the clutch and safety valves (6, 13) are both closed by the reduced pressure fluid thereby preventing the flow of pressurized fluid to the actuation piston, and when pressure control valve (11) is open, the flow of pressurized fluid to the actuation piston (23) is allowed by the safety and clutch valves (6, 13) thereby allowing engagement of the clutch and the locking of the

Abstract: Electric-hydraulic control for an automatic transmission (1) with a selecting slide (4), at least for the neutral position (N), as well as the forward drive position (D) and the reverse drive position (R), an electronic control device (5), which is connected to at least one sensor (55) for detecting the gear output speed, with solenoid valves (6, 65) held in neutral position by spring force, a pressure-medium source (7), pressure-control valves (8) and switch valves (9) and dampers for the actuation of gear-selecting clutches and -brakes (A-E) as well as with a R-gear safety mechanism which is created by the cooperation of a solenoid valve (6) and a switch valve (9), both of them being already used in other gear-selecting operations.

Abstract: Electrohydraulic control for an automatically shiftable automotive transmission with a selection slide valve (2), at least for the neutral position (N), as well as for the drive mode (D) and reverse mode (R), an electronic control device (3) having solenoid valves (4) held in neutral position by spring action, a pressure-medium source (1), pressure control and gear control valves (5, 6, 7) for the actuation of gear engagement couplings and brakes (A-F), as well as with a R-gear safety valve (8), for preventing the shifting into the R-gear when the forward drive speed is still too high, and a system which, in the case of electronic failure, holds or shifts the automatic transmission to one gear insuring that the maximum permissible rotational speed of the engine is not exceeded when the vehicle travels at maximum speed, whereby, in the event of failure of the electronic control device (3) during driving, a control system holds or shifts the gear, and in the event of failure of the electronic control device (3)

Abstract: An electrohydraulic control for an automatically shiftable transmission (G 1) has at least two solenoid valves (1a, 1b) which are connected via the control pressure lines (13, 14) with gear control valves (2, 3) and these with coupling valves (4, 5) and shock absorbers (6, 7) via system pressure lines (260, 261, 262) for the engagement of the couplings (C, C'). In order to shift into a gear, two couplings are engaged and the coupling valves have an additional connection for the supply of a load-dependent modulation pressure. Via a control pressure line (14), system pressure lines (330, 331, 332 and 530, 531) as well as a modulation pressure line (17), a gear-control valve (3) and a coupling valve (5) with a shock absorber (6 ) are connected in such a manner that one of the couplings (C') is closed with a delay. Due to this delay, a smoother shifting results, particularly when shifting with a zero load or in the lower load range.

Abstract: Electro-hydraulic control for an automatic transmission (1) is disclosed with two primary shafts (11, 12), whereby the first shaft (11) is connected with a turbine (21) of a hydrodynamic unit (2) and the second shaft (12) is directly connected to the driving shaft (31) of a driving motor (3) and the driving output is directed depending on speed, individually or by power split, to the for instance stepped-down planetary gear with a selecting slide (4) at least for the neutral position (N), as well as the forward drive- (D) and the reverse drive position (R) and an electronic control device (5) with solenoid valves (6), kept in zero position by spring force, for a pressure-medium source (7), pressure- and switch valves and dampers for the actuation of gear shift couplings and brakes (A-E), whereby between a solenoid valve (6) and the gear shift couplings for the highest speed (E) as well as the reverse drive (B) an emergency valve (8/9) is interposed.

Abstract: A vehicle driven by a super charged engine has a gear transmission that is automatically shifted between drive ratios under the joint control of vehicle speed and engine load demand, modified by a loading signal pressure derived from the engine carburetor to correctively influence the change in drive ratio so as to accommodate a super charged type of engine. Such loading signal pressure is applied to a shift valve of the transmission control system independently of control pressure reflecting vehicle speed and engine load demand in order to correctively modify the pressure control exercised during the drive ratio change interval.

Abstract: A control valve for a torque converter, that has a bridge coupling, in a hydrodynamic-mechanical transmission for motor vehicles. The valve serves to control, by means of a fluid pressure, the bridge coupling of the torque converter to which a mechanical transmission is connected in series. The operational pressure can depend on the position of the power control apparatus of the driving engine and/or on the speed of the engine or the take-off axle of the transmission.

Abstract: A hydraulic control system for a hydrodynamic/mechanical transmission with hydraulically actuated clutches for selecting the "gears" or "speeds" of the mechanical transmission comprises a hydraulic-pressure source, e.g. a pump connected with the crank shaft of an engine, delivering hydraulic fluid to the clutches via a main pressure line. The pressure in this line is controlled by a main pressure valve such that the excess fluid is supplied to the feed line of the hydrodynamic unit of the hydrodynamic/mechanical transmission, e.g. a torque converter or fluid coupling. At higher fluid excesses in the main pressure line, the hydraulic fluid is bypassed to the intake side of the source between a filter and the pump. The system includes a further pressure valve which constitutes the pressure control valve for the hydrodynamic unit, the latter valve having only two controlled ports and being free from any port connected to the reservoir.