Interrelated power delivery controls – including engine control – Transmission control – Transmission controlled by engine
Patent
1996-11-15
1998-07-28
Bonck, Rodney H.
Interrelated power delivery controls, including engine control
Transmission control
Transmission controlled by engine
477128, 477121, F16H 6102
Patent
active
057856290
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a process for controlling an automatic transmission.
In a first kind of automatic transmissions known from the prior art, for example, EP-PS 0 324 758, a clutch valve is coordinated with a clutch. The clutch valve here determines the pressure curve and the pressure level in the clutch during a gearshifting operation. The clutch valve consists of a valve slide with control pistons, a pressure spring and a piston. The pressure spring supports itself, on one side, on the valve slide with control pistons and, on the other side, on the inner side of the piston. The piston is movable, the same pressure level appearing on the outer side of the piston as in the clutch. The force resulting from the pressure moves the piston. Said force is oriented opposite to the force of the pressure spring. The constant stiffness and the pitch of spring thus establish a gradient of the pressure ramp on the clutch and the height of the pressure. The inner side of the piston can, in addition, be loaded with pressure. It is accordingly possible, by said added pressure, to raise the pressure ramp. The load take-up point of the clutch falls in the area of the pressure ramp. On the load take-up point the clutch takes over the engine torque. The pressure level on the inner side of the piston is determined by an electromagnetic pressure regulator of an electronic control device. It is known that on the basis of different input quantities such as engine torque, vehicle speed and throttle-valve signal, the electronic control device calculates the pressure level in the clutch to be gearshifted. The electronic control device differentiates here an upshift or a downshift and a first or second change range, that is, push or pull. In changes near the push/pull transition, the electronic control device calculates, based on the input quantity, a lower pressure value for the piston inner side of the clutch valve. Due to the pressure spring, a ramp-shaped pressure curve appears on the clutch so that the clutch reliably takes over the engine torque.
In a second kind of automatic transmission also known from the prior art, for example, EP-PS 0 440 748, an electromagnetic pressure regulator directly determines the pressure curve of the clutch to be gearshifted. The electromagnetic pressure regulator here reproduces the pressure ramp. In gearshifts near the push/pull transition, the problem that the electronic control device calculates a low pressure value on the basis of the input quantity appears. This, in turn, causes that the load take-up point of the clutch to be gearshifted very late in time so that long gearshifting times can occur. For reasons of safety, such automatic transmissions have a timed step which limits the maximum gearshifting time. After expiration of said time step, the clutch to be gearshifted necessarily becomes engaged with a very high pressure level. This causes a notable shifting jolt and an unacceptable loss of comfort.
The problem to be solved by the invention is to avoid said disadvantages in an automatic transmission of the second kind.
According to the invention the problem is solved by a process for control of an automatic transmission with clutches, the shifting state and pressure curve of which are determined by electromagnetic adjusting members of an electronic control device, said electronic control device, on the basis of input quantities, detects a driver's demand change to upshift or downshift and herefrom determines a mode of changing. The mode of changing corresponds to an upshift by one gear, or a downshift by one gear, or a downshift by more than one gear. From a parameter representative of the driver's desired performance and a speed of an internal combustion machine or output speed of the automatic transmission, the electronic control device determines an existing operation point and, via a performance graph, selects a first or second change range, said performance graph containing coordinations of theoretical operating points with the changing mode. The solution offers the advantage t
REFERENCES:
patent: 4753134 (1988-06-01), Hayasaki
patent: 4955259 (1990-09-01), Narita
patent: 5016175 (1991-05-01), Baltusis et al.
patent: 5166879 (1992-11-01), Greene et al.
patent: 5168777 (1992-12-01), Isono et al.
patent: 5396420 (1995-03-01), Graf
patent: 5417626 (1995-05-01), Gierer
patent: 5436834 (1995-07-01), Graf et al.
patent: 5459658 (1995-10-01), Morey et al.
patent: 5470288 (1995-11-01), Palansky et al.
patent: 5475590 (1995-12-01), Palansky et al.
patent: 5568748 (1996-10-01), Carlson et al.
patent: 5603672 (1997-02-01), Zhang
patent: 5618243 (1997-04-01), Kondo et al.
Gierer Georg
Wiest Wolfgang
Bonck Rodney H.
Kwon Peter T.
ZF Friedrichshafen AG
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