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:
Es wird ein Verfahren zum Steuern eines Antriebsstranges eines Fahrzeugs mit einer Antriebsmaschine und mit einem Getriebe, dessen Übersetzung innerhalb eines Übersetzungsbereiches automatisch stufenlos und/oder gestuft variierbar ist, in Abhängigkeit vorgebbarer und über eine Fahrzeuggeschwindigkeitsregelung einstellbaren Ziel-Geschwindigkeiten (v_ziel) und aktueller auf eine Fahrzeuglängsachse bezogene Fahrzeugneigungen beschrieben. Erfindungsgemäß wird bei aktivierter Fahrzeuggeschwindigkeitsregelung und einer Abweichung der Ist-Geschwindigkeit (v_ist) des Fahrzeugs von einer vorgegebenen Ziel-Geschwindigkeit (v_ziel) des Fahrzeugs eine Anforderung zum Verändern einer aktuellen Übersetzung (i_ist) des Getriebes generiert, wenn ermittelt wird, dass das mit der Ist-Übersetzung (i_ist) des Getriebes am Abtrieb des Antriebsstranges darstellbare Abtriebsmoment kleiner als ein Schwellwert oder kleiner als ein zum Einstellen der vorgegebenen Ziel-Geschwindigkeit (v_ziel) des Fahrzeugs erforderliches abtriebsseitiges Abtriebsmoment ist, wobei die Übersetzung (i_ist) des Getriebes derart variiert wird, dass das am Abtrieb darstellbare Abtriebsmoment in Richtung des zum Einstellen der Ziel-Geschwindigkeit (v_ziel) erforderlichen Abtriebsmomentes verändert wird.
Abstract:
A method for controlling a motor vehicle fitted with a manual gearbox, whereby said vehicle is provided with a clutch, a manual gearbox and an engine. The acceleration (1) of the motor vehicle is set by means of a control device and reduced before changing gear to a first acceleration value (3). The acceleration value is reduced to a second value that is lower than the first value after a specific time period has elapsed.
Abstract:
Proposed is a method of controlling and regulating an automatic gearbox with overlapping gear shifts. The invention calls for the disengaging coupling (11) to be changed over from the control mode to the regulating mode if defective engagement of the engaging coupling (12) is detected.
Abstract:
The invention relates to a vehicle integrated-control apparatus and method that sets a final control target by coordinating a control target (FO) primarily set based on an input of a driver with instruction values from the control systems; and that causes a drive control system to control a drive source (140) and a stepped automatic transmission (240) to achieve the final control target. With this apparatus and method, at least one of the control systems, which provide instruction values to be coordinated with the primarily set control target, is notified of a range of control targets that can be achieved at a current shift speed; a range of control targets that can be achieved by changing the current shift speed to a currently achievable shift speed; and a range of control targets that can be achieved without changing the current shift speed to another shift speed.
Abstract:
The present invention relates to a method for determination of one or more shift points for a gearbox in a motor vehicle which comprises an engine connected to, in order to drive, said gearbox, where a shift point represents an engine speed at which said gearbox is adapted to effecting a downshift or upshift, said one or more shift points are determined on the basis of an engine target speed ω T and a first engine speed difference Δω TT , said target speed ω T is a desired speed for said engine, said first engine speed difference Δω TT is a difference between a first engine speed at a first time t 1 and said target speed ω T at a second time t 2 , and said first and second times t 1 and t 2 are separated by a time period T . The invention relates also to a system, a motor vehicle, a computer programme and a computer programme product thereof.
Abstract:
The invention relates to a hydraulic changing device for a multi-ratio vehicle gearbox, especially for commercial vehicles, e.g. a mobile excavator. The hydraulic changing device feeds gear actuators (3, 4) with a pressure medium conveyed by a servo pump (10). There is a control slide (26) which is acted upon by the effect of a control spring (33) on the one hand and by a pressure in a low-pressure chamber (23) on the other. The low-pressure chamber (23) is coupled to a low-pressure pump (20) operating in dependence upon the motor speed. The arrangement is completed by a shuttle valve (6) and a leakage valve (5). The pressure prevailing in the low-pressure chamber actuates the control slide (26) against the force of the control spring (33) in such a way that undesired changes from a higher to a lower gear are prevented. The hydraulic changing device of the invention is distinguished by its low structural and design expenditure.
Abstract:
In a process for controlling an automatic gearbox wherein a transition occurs from a first, lower reduction step to a second, higher reduction step when a first clutch opens and a second clutch closes and a synchronizer speed is calculated by multiplying the gearbox output speed by the reduction ratio of the second reduction step, a speed value at which the pressure decrease of the second clutch begins is assigned to the synchronizer speed from a characteristic curve. The characteristic curve is adapted if the gearbox input speed becomes greater than the synchronizer speed or if the gradient of the gearbox input speed exceeds a limit value.
Abstract:
A speed change control method for an automatic transmission for realizing a smooth skipping downshift even when the driver steps on the accelerator in a gentle fashion at the time of kick-down. An electronic control unit (6) calculates a deviation between a throttle valve opening theta t1 at a time when a predetermined period of time has elapsed after it outputs an instruction to effect a downshift from the fourth gear to the third gear and a throttle valve opening theta ts when the downshift instruction is outputted and a variation rate ( theta t1)' of a throttle value opening at the elapsed time, and outputs (S12) an instruction to cancel the already-outputted instruction of the downshift from the fourth gear to the third gear in a case where the deviation so calculated is found to be greater than a threshold value DELTA theta and the variation rate so calculated is greater than a treshold value DELTA ( theta )' (S10, S11), and also outputs (S13) an instruction to effect a downshift from the fourth gear to the second gear.