Abstract:
Die Erfindung betrifft ein Verfahren zur Steuerung eines zumindest teilweise unsynchronisierten Schaltgetriebes, welches während eines Übersetzungsänderungsvorgangs die Erhöhung einer Drehzahl zumindest eines zu synchronisierenden Getriebeteils dadurch realisiert, dass zumindest ein Element des Getriebes über eine schaltbare Kupplung mit einem Antriebsmotor verbunden wird, und dieser Antriebsmotor die erforderliche Drehzahl und das benötigte Drehmoment an seiner Abtriebswelle zur Verfügung stellt. Zudem ist vorgesehen, dass dann, wenn die vom Antriebsmotor bereitgestellte Drehzahl undioder das bereitgestellte Drehmoment innerhalb eines festgelegten Zeitraumes nicht ausreicht um die Synchronisierung des Schaltgetriebes zu gewährleisten, eine Schaltstrategie verfolgt wird, weiche ein unbeabsichtigtes Verharren des Schaltgetriebes in dessen Neutraistellung oder Leerlaufstellung verhindert.
Abstract:
The invention relates to a method for controlling the automatic gearbox of a motor vehicle provided with an electronic gear control, whereby a spontaneous release of the accelerator pedal (FastOff) is detected and a system that prevents shifting to a higher gear is activated when a pedal position gradient (PSTG) is lower than a threshold value for said pedal position (KF_PSTG) that is stored in a family of characteristics as a function of a pedal position value (PST) and a driver-type evaluation counter (COUNT); the state of the system preventing shifting to a higher gear (FFO=1) remains active until a) a traction mode is detected, when the real pedal position value (PST) goes beyond a traction/thrust characteristic (KF_ZS); and/or b) a time (T1, T2) has elapsed after a defined period (THSV1, THSV2).
Abstract:
When during driving an electric fail occurs and when any gear stage out of forward gear stages is kept effective in step 5, a friction element to be coupled at this gear stage is compared with a friction element currently coupled by switch signals from hydraulic switches 11, 12, 13, 14, 15, a failing electric system is judged when they do not agree, and the system proceeds to step 6 and beyond when this electric fail is judged to fix the gear stage of the automatic transmission to a specific gear stage. Accordingly, a shift control device for an automatic transmission is provided that can positively prevent interlocks by eliminating sleeping fails, and ensure a high shift control performance not limiting the hydraulic control ranges of respective friction elements at switching shifting.
Abstract:
For motor vehicles equipped with overdrive-equipped transmissions normally biased in one of the overdrive or non-overdrive modes of operation, a method for automatically biasing the transmission (100) to the alternate mode of operation, and apparatus (10) to pratice the method. Normally used to bias transmissons (100) from the overdrive to the non-overdrive mode of operation, the apparatus (10) and method taught herein are particularly well-suited for operation in conjunction with automatic transmissions, and are actuated uniquely with each ignition run cycle. Alternatively, the method and apparatus (10) may, with equal facility, incorporate other vehicle operations and conditions to actuate its overdrive biasing function.
Abstract:
A clutch control system for the automatic control of a motor vehicle clutch which connects an engine with a gearbox under the control of a driver operated gear ratio selector lever. The control system controls both initial clutch take-up on starting of the vehicle, clutch re-engagement following each ratio change, clutch disengagement on movement of the gear selector lever to change the operative ratio of the gearbox, and clutch disengagement on the coming to rest of the vehicle. The clutch control system also warms (50, c) the operator if he attempts to drive away in a designated non take-up gear or in any gear in a predetermined abusive manner and may be arranged to promote rapid engagement or disengagement of the clutch in certain abusive conditions to reduce energy generation in the clutch.
Abstract:
A detector switch is provided to confirm that an electric signal from the controller to the electromagnetic valve is transformed into the operation of a control valve spool when the speed of an automobile or a construction machine is changed through a transmission. Therefore, the control valves (11, 12, 13) are provided with the detector switch (7) that is capable of transmitting a signal to the controller (5) when a valve spool (3) has come in contact therewith in a transmission that has the spool (3) for switching the electromagnetic valves (21, 22, 23) connected to the controller (5) to change the clutch hydraulic pressure to change the speed.
Abstract:
The invention concerns an engine-rpm-dependent arrest device to prevent non-permitted down shifts in motor vehicle gearboxes, comprising a pilot valve (1) and a control valve (2), both of which have two positions. The control valve (2) is switched into one position by the pressure acting on the surface (36) of the control-valve piston (31), when this pressure exceeds a given pressure produced by a low-pressure pump (20) operating in dependence on engine rpm. The control valve (2) is only in contact with the pressure medium conveyed by the low-pressure pump (20) and controls the large end surface (40) and the annular surface (41) of the stepped-design pilot-valve piston (38). If, with a high gear engaged and motor rpm above a given limit, the gear-shift valve (7) is shifted to its low-gear position, the pilot valve (1) prevents pressure acting on the low-gear activation device (15). At the same time, pressure continues to act on the high-gear activation device (16), thus keeping the gearbox in the high gear.
Abstract:
Method for automatic gear selection in a vehicle power transmission, said selection being catered for by a control system including an electronic unit (1) which, in response to signals representing vehicle speed and engine load, coacts with a programmable read-only memory PROM (28), in which there are stored, for each gear position, alternative speed limits for changing gear to neighbouring gears and also limiting values relating to speed change and engine load for selection between said alternative speed limits. To eliminate the risk of unsuitable gear selection for heavy vehicles, e.g. in conjunction with changing gear on a hill, the invention is essentially distinguished in that during travel, data on speed change and engine load are stored in a random access memory RAM (29); that the speed value most recently stored in said RAM before the initiation of the gear selection is compared, together with values stored in said RAM and relating to speed change and engine load at a certain instant before the initiation of the speed change, with values stored in said PROM and relating to speed, speed change and engine load, respectively; that said comparison results in the choice of a certain gear; that in the electronic unit (1) there is generated an output signal representing the selected gear; and that said output signal is fed to an operative means for indicating and/or engaging the selected gear.
Abstract:
When shifting an automatic transmission (3) into a higher gear, it is determined that an inertia phase has started when an input rotation speed of the automatic transmission (3) has started to decrease. Here, if throttle opening amount reduction control is being performed to reduce the output torque of the engine (2) when it is determined that the inertia phase has started, it is highly likely that determination is erroneous because that control causes the input rotation speed of the automatic transmission (3) (i.e., the engine speed) to decrease. When it is highly likely that the determination that the inertia phase has started is erroneous in this way, learning of a hydraulic pressure command value (Pt) is prohibited. As a result, erroneous learning of the hydraulic pressure command value (Pt) can be prevented.