Engine torque control system based on the dynamic behavior of a driven automatic transmission

#This invention relates to a method for adapting the dynamics of the torque build-up of a motor vehicle to the dynamics of an automatic transmission it drives, which can be designed as continuously variable transmission or continuously variable automatic transmission, by means of pre-conditioning the hydraulic system in the automatic transmission in the sense that the hydraulic pressures be kept within a range from which an increase of the pressures to eventually needed higher pressures is possible in sufficiently short time and by means of reducing the engine dynamics by an external engagement originating from the transmission.

#In modern engines of motor vehicles the dynamics of the torque build-up becomes continuously higher. Specially in modern diesel engines for passenger motor vehicles already 60 ms after actuating the accelerator pedal the torque produced thereby can build up on the crankshaft.

#The dynamics of an engine cannot be followed by the dynamics of an automatic transmission it drives with the build-up of pressures on clutches in case of a continuously variable automatic transmission or with the build-up of pressures on the adjusting elements for the variator in CVT transmission. Depending on the operating point, starting from which the hydraulic system of the transmission must move, the required contact pressure on the clutches in the case of continuously variable automatic transmissions or frictional elements in the case of continuously variable transmissions cannot be built up with the needed speed in order to cope with the quickly increasing engine torque.

#The invention is explained herebelow with reference to the drawing where in the single figure is shown a graphic representation of the distribution of the portions of pre-conditioning and of reduction of the engine dynamics according to the sportiveness factor.

#In this graphic representation, the sporting mode is plotted on the abscissa in the form of the detected sportiveness factor and on the ordinate the portion of the two solutions 1 and 2 described above as first method and second method. As can be seen in the extreme point A, that is, with low sportiveness factor, the solution 2 is fully used, that is, a reduction of the engine dynamics by an external engagement originating from the transmission which, for ex., via the CAN bus, sends a notice to the engine and wherein only a certain engine dynamics is admissible. The transmission is here driven by the pressures into a favorable efficiency range. The engine dynamics is therefor maximally limited insofar as required by the dynamics of the automatic transmission.

#As the sportiveness factor increases a change is now more and more effected to the solution 1, that is, the pre-conditioning of the hydraulic system for a quickly increasing engine torque. The dynamics of the engine is thereby continuously less limited for which the automatic transmission must always be more strongly pre-conditioned. In the extreme point B, only the first solution is used, that is, the pre-conditioning. The dynamics of the engine is no longer limited in the extreme point B, but for this the automatic transmission has to be maximally pre-conditioned insofar as required by the dynamics of the engine.

#1 portion of the pre-conditioning