DE102004057834A1 - Method for adjustment of driving engine of motor vehicle, involves independent determination of drive input torque and driving resistance torque, along with reference torque provided for correction of driving resistance torque - Google Patents

Abstract

The method involves independent determination of the drive input torque (Mf) and driving resistance torque (Mw). A reference torque (Msoll) is provided for correction of the driving resistance torque, at least when the drive input torque is greater than the driving resistance torque.

Description

The The invention relates to a method for adjusting one of A desired engine torque to be output to a drive motor of a motor vehicle according to the preamble of claim 1.

One Such method is in the form of so-called traction control systems or traction control systems sufficiently well known. This is basically a Reduction of engine torque, usually in principle determined by a driver's request moment, made when slip on the drive wheels occurs.

From the DE 100 18 381 A1 For example, a method for adjusting a drive torque is known in which the driving resistance is taken into account.

It Object of the invention, a traction control system mentioned above Type with regard to the control quality and with regard to reducing emissions.

These The object is achieved by the Characteristics of claim 1 solved. Advantageous developments are the objects the dependent Claims.

The invention is based on the following findings:
A traction control has to be able to work very fast in order to work as well as possible. This can usually be ensured simply by means of ignition interventions. The disadvantage of ignition interventions, however, is that thereby the efficiency of the engine is deteriorated and thus a consumption and emission increase is the result. In addition, complete spark suppressions cause vibrations that mechanically stress the engine and driveline. Ignition angle reductions cause increased thermal load. Therefore, in the prior art systems with pure throttle control are preferred. However, these are slower for physical reasons and therefore technically more difficult to control.

The The present invention therefore provides acceleration of traction control a feedforward control in terms of drive power depending From driving resistance and thus attacks even before the emergence a control error due to a changing driving condition.

Therefore is a target torque to be delivered by the drive motor, at least in the case that the driver's request moment is greater than the driving resistance torque is given by a correction of the driving resistance torque. Thus, in the presence of increased Slip this regulated faster. There is little slip before, the driver's desired Moment reached quickly.

In The drawing is a particularly advantageous embodiment for the inventive method shown in the form of a block diagram. The this block diagram The underlying function can, for example, be in the form of a software module in one anyway usually integrated electronic engine or traction control unit be.

In a first block 1 is a driver's request torque M _F, for example, determined as usual from the position of an accelerator pedal FP and the engine speed n. In a second block 2 a driving resistance torque M _{W is determined} in particular from the vehicle speed v, the longitudinal acceleration a _L , the lateral acceleration a _Q and the vehicle mass m. This driving resistance torque M _W is precontrolled and can be corrected at the multiplication point X, for example by means of a correction factor F. The correction factor F can lead to an increase (F> 1) or to a reduction (F <1) of the driving resistance torque M _W. Various ways of determining a driving resistance torque are known and are for example in the DE 100 18 381 A1 described.

The driver request torque M _F and the driving resistance torque M _W are input signals of a slip controller 3 , Through the slip control 3 the correction factor F is determined depending on the slip at the drive wheels and on the difference between the driver request torque M _F and the driving resistance torque M _W. If the actual slip s _is greater at the drive wheels than a predetermined desired slip s _soll , the pre-controlled driving resistance torque M _{W is} reduced until the actual slip s _{ist is} smaller than the setpoint slip s _soll . If the actual slip s _ist at the drive wheels is smaller than a predetermined setpoint slip s _soll , the pre-controlled road resistance torque M _{W is} corrected in the direction of the driver's desired torque M _F. In principle, this can lead both to an increase and to a reduction of the driving resistance torque M _W.

Preferably, however, the desired driver torque M _{F is} instantaneously preselected as the desired torque M if the driver request torque M _{F is} less than the driving resistance torque M _W or the currently present corrected driving resistance torque M _corr . This development of the invention makes sense, in particular in the case of an abrupt release of the accelerator pedal. This function is in particular through the minimum selection block 4 ensures whose output signal is to be output by the drive motor of the motor vehicle target torque M _soll .

Claims (3)

A method for setting a target torque to be output by a drive motor of a motor vehicle as a function of a determined driver request and the slip on the drive wheels, characterized in that a driver request torque (M _F ) and a driving resistance torque (M _W ) determined independently and that a target torque (M _soll ), at least in the event that the driver's desired torque (M _F ) is greater than the driving resistance torque (M _W ), set by a correction of the driving resistance torque (M _W ) becomes. Method according to claim 1, characterized in that, if the actual slip (s _ist ) at the drive wheels is greater than a predetermined target slip (s _soll ), the driving resistance torque (M _W ) is corrected in the direction of reduction until the actual slip (s _ist ) is smaller than the target slip (s _soll ) and that when the actual slip (s _ist ) at the drive wheels is less than a predetermined target slip (s _soll ), the driving resistance Moment (M _W ) in the direction of the driver's request torque (M _F ) is corrected. A method according to claim 1 or 2, characterized in that as the desired torque, the driver's desired torque (M _F ) is specified when the driver's request torque (M _F ) is smaller than the driving resistance torque (M _W ) or the currently present corrected Travel resistance torque (M _korr ) is.