Method of and apparatus for transmitting torque in the power trains of motor vehicles

A method of regulating a torque transmitting system which forms part of a power train, said power train having an operating condition and said torque transmitting system (a) being operatively connected with the output of a prime mover, (b) being drivingly connected with an automatic transmission by an output shaft, and (c) comprising a hydrodynamic power transmission, a friction clutch in parallel with the power transmission and a central computer unit, a force adapted to be applied to and a torque adapted to be transmitted by the friction clutch being variable under the influence of the central computer unit, said method comprising the steps of determining the torque which is to be transmitted by the friction clutch in dependence upon the operating condition of the prime mover in accordance with the torque equation M.sub.clutch =k.sub.c .multidot.k.sub.korr .multidot.M.sub.prime mover, wherein k.sub.c =k.sub.mc constituting a torque division factor and k.sub.korr is a correction factor, and computing, selecting and applying to the friction clutch that force which is required for the transmission of the predetermined clutch torque so that a slippage between an input and an output of the torque transmission system is automatically determined in dependence upon the torque division factor k.sub.c, which is a constant within the operating range of the power train, and the correction factor k.sub.korr compensates for departures of the power train from an ideal condition.

A method of regulating a torque transmitting system which is operatively connected with an output of a prime mover, said prime mover having an operating condition and said torque transmitting system (a) being drivingly connected with an automatic transmission by an output shaft and (b) comprising a hydrodynamic power transmission, a friction clutch in parallel with the power transmission and a central computer unit, the application of a force to the friction clutch and hence a torque which is being transmitted by the friction clutch being variable under the influence of the central computer unit, said method comprising the steps of ascertaining the torque to be transmitted by the friction clutch in dependence upon the operating condition of the prime mover in accordance with the torque equation M.sub.clutch =k.sub.c .multidot.k.sub.korr .multidot.M.sub.prime mover, wherein k.sub.c =k.sub.mc constituting a torque division factor and k.sub.korr is a correction factor, and computing, selecting and applying to the friction clutch that force which is required for the transmission of the ascertained clutch torque so that a slippage between an input and an output of the torque transmitting system is automatically determined in dependence upon the magnitude of the torque division factor k.sub.c, which is independent of a characteristic diagram of the prime mover, and that the correction factor k.sub.korr compensates for deviations of a condition of the power train from an ideal condition.

A method of regulating a torque transmitting system which is operatively connected with an output of a prime mover, said prime mover having an operating condition and said torque transmitting system (a) being drivingly connected with an automatic transmission by an output shaft and (b) comprising a hydrodynamic power transmission, a friction clutch in parallel with the power transmission and a central computer unit arranged to regulate the application of a variable force to the friction clutch, and hence a torque which is being transmitted by the friction clutch, said method comprising the steps of ascertaining the torque to be transmitted by the friction clutch in dependence upon the operating condition of the prime mover in accordance with the torque equation M.sub.clutch =k.sub.c .multidot.k.sub.korr .multidot.M.sub.prime mover, wherein k.sub.c =k.sub.mc constituting a torque division factor and k.sub.korr is a correction factor, and computing, selecting and applying to the friction clutch that force which is required for the transmission of the ascertained clutch torque so that a slippage between an input and an output of the torque transmission system is automatically determined in dependence upon the magnitude of the torque division factor k.sub.c, which is dependent exclusively upon the RPM of the prime mover, and that the correction factor k.sub.korr compensates for deviations of the condition of the power train from an ideal condition.

A method of regulating a torque transmitting system which is operatively connected with an output of a prime mover, said prime mover having a variable operating condition and said torque transmitting system (a) being drivingly connected with an automatic transmission by an output shaft and (b) comprising a hydrodynamic power transmission, a friction clutch in parallel with the power transmission and a central computer unit arranged to regulate the application of a variable force to the friction clutch, and hence a torque which is being transmitted by the friction clutch, said method comprising the steps of ascertaining the torque to be transmitted by the friction clutch in dependence upon the operating condition of the prime mover in accordance with the torque equation M.sub.clutch =k.sub.c .multidot.k.sub.korr .multidot.M.sub.prime mover, wherein k.sub.c =k.sub.mc constituting a torque division factor and k.sub.korr is a correction factor, and computing, and selecting and applying to the friction clutch that force which is required for the transmission of the ascertained clutch torque so that a slippage between an input and an output of the torque transmitting system is automatically determined in dependence upon the magnitude of the torque division factor k.sub.c, which is a function of the RPM and of the torque of the prime mover, and that the correction factor k.sub.korr compensates for deviations of the condition of the power train from an ideal condition.

A torque transmitting system for a power train of a vehicle which is equipped with a variable-speed transmission, particularly a motor vehicle with a prime mover including a combustion engine, comprising:

• a hydrodynamic torque transmission which is connected to and is driven by said prime mover of the vehicle and has an output shaft operatively connecting it with a following automatic transmission;
• a friction clutch which is disposed in parallel with the hydrodynamic torque transmission, which is actuatable by a flowing pressurized fluid, and which is provided with a first plenum chamber between a turbine wheel of the power transmission and an annular piston which is operatively connected with a friction disc and with a second plenum chamber between the annular piston and a cover of the power transmission, said chambers being configurated in such a way that a pressure differential existing between said chambers determines the torque which can be transmitted by the friction clutch;
• a central computer unit;
• and a hydraulic system which can cooperate with the computer unit to bring about a directed change of the pressure differential between said chambers and hence a change of the torque adapted to be transmitted by the friction clutch, the friction clutch being regulated at all speed ratios and the power transmission having a torque conversion ratio>2.5.

A torque transmitting system for the power train of a vehicle which is equipped with an automatic variable-speed transmission and with a drive, comprising:

• a hydrodynamic torque transmission which is driven by a power train of the vehicle and is operatively connected with said automatic transmission;
• a friction clutch which is disposed in parallel with the hydrodynamic torque transmission, said friction clutch being actuatable by a flowing pressurized fluid and being provided with a first plenum chamber between a turbine wheel of the torque transmission and an annular piston which cooperates with a friction disc, and with a second plenum chamber between the annular piston and a cover of the torque transmission, the chambers being configurated in such a way that a pressure differential existing between said chambers determines the torque which can be transmitted by the friction clutch;
• a central computer unit;
• and a hydraulic system adapted to cooperate with the computer unit to bring about a directed change of the pressure differential between said chambers and hence a change of the torque adapted to be transmitted by the friction clutch, said friction clutch being operated in such a way that a partial engagement between said piston and said friction disc takes place, at least at times, at all forward speeds.