System for reducing instabilities in vehicle acceleration dynamics.

The invention relates to a device for reduction of vehicle longitudinal dynamics instabilities according to the preamble of claim 1.

The longitudinal vehicle dynamics instabilities manifest themselves in the fact that also undesirable periodic acceleration changes caused the arbitrary acceleration by depressing the accelerator. The accelerations are transmitted to the driver, who thus causing an undesired change of position of the accelerator pedal. The whole vibration system comprising the vehicle with elasticities in the driveline, masses to be accelerated and moments of inertia and the power output of the engine according to the operating point in the torque / speed characteristic and other factors may be unstable. This can lead to a tread that vibration, in the extreme case almost all Gaspedalstellweg will undergo involuntary (bonanza effect).

To remedy this undesirable phenomenon which occurs in particular in internal combustion engines with a steep torque / speed characteristic, attempts have been made, the

Longitudinal vibrations of the vehicle / driver system thereby attenuate that the accelerator pedal is connected via a delay element with the actuator in connection, which controls the air-fuel mixture of the Ver_brennungsmotors. The delay has been achieved in particular by a hydraulic damper. - The disadvantage of this damping action is that the randomly triggered by the driver adjustment of the accelerator pedal will also have a delayed effect in corresponding positions of the actuator. By this damper in the connection between accelerator pedal and actuator therefore occurs an undesirable delay in the response of the internal combustion engine. In addition, coordination problems of the damper, as in the connection between the accelerator pedal and the engine to be damped periodic oscillation of the vehicle type and - depending on the selected gear - for given vehicle type. Basically, this known method to the apparent improvement in the vehicle's longitudinal stability is also ineffective if the disturbing suggestions of the vibrations are not introduced via the accelerator pedal, but in other places, for example, by switching or coupling operations or road unevenness.

The invention is therefore based on the object to provide a device which effectively reduces the harmful effects of vehicle longitudinal dynamics instability independent of the attack point of the interference, the parameters of which are not critical set and what response the. behavior of the engine in an arbitrary accelerator operation does not deteriorate significantly.

This object is achieved by the specified in the characterizing part of claim 1 invention.

The solution based on the principle that a suitable signal is derived from the engine speed, which is to the purpose of regulation on minimum jerk of the vehicle, the fuel controller LuftgemischesYrückgeführt. For this, the changes in speed of the motor are detected and if they are detected randomly triggered as disturbing, that is not by the driver, implemented in opposite position changes of the actuator. Arbitrary changes accelerator by the driver are not affected by the damping device. More specifically, this damping of the vehicle longitudinal dynamics instabilities is performed by electrical means, by deriving from the engine speed emeelektrische voltage, which is then differentiated and transmitted via a limiter amplifier.

according to claim 2 of the engagement of this limiter amplifier is limited particularly expedient to approximately 50% of the working range of the adjustment of the actuator. Thus a safe compensation of parasitic oscillations is ensured, on the other hand, the Kompansation is not detrimental at random acceleration, deceleration by the driver from.

Particularly appropriate this device is combined with a conventional device for the electrical adjustment of the regulator on the gas. The coupling of the output from the limiter amplifier signal is expediently at the output of the device for electrical adjustment of the regulator by the accelerator (E-gas). - In this combination of the overhead of the means for reducing the disruptive effects of vehicle longitudinal dynamics instability is particularly low since the adjustment of the regulator is performed by electromechanical means.

The invention is illustrated below with reference to a drawing with a figure in which a signal flow of the device is shown in conjunction with an electronic throttle device:<ul><li>In Fig. 1, an accelerator pedal (accelerator pedal) is denoted by 1, the position of which via an electrical position transmitter 2 is converted into an electrical position signal. This signal is amplified by an amplifier 3 and is converted into a corresponding position of an electromechanical actuator 4, which determines the air-fuel mixture of an internal combustion engine. 5</li></ul>

With this conventional electronic throttle device following device for reduction of vehicle longitudinal dynamics instability coupled:<ul><li>With a rotatable member of the engine is a rotational speed sensor 6 in connection, which provides an electrical speed signal corresponding to the engine speed. This speed signal is converted into a speed voltage transformer into a proportional voltage. This voltage is in a differential element 8, which can be realized by a conventional resistor capacitor combination, differentiated and supplied to a limiter amplifier. 9 As shown with the direction indicated in the limiter-amplifier block characteristic curve 10, the amplifier amplifies approximately linear as long as its output voltage does not exceed a predetermined voltage range. Beyond this range the amplifier but no longer amplified, but its output voltage is held constant at a maximum value. This limiter circuit can be realized in a customary manner with a Zener diode.</li></ul>

The output of the limiter-amplifier is coupled to a coupling point 11 in the signal flow of e-gas facility.

This facility will be periodic oscillations on _Fahrzeuglängsdynamik instabilities are due, as has been shown practically completely, since any change in speed of the engine an opposite change in the adjuster position causes immediately, so that the fuel-air mixture is influenced in compensating sense. - Pressing the accelerator pedal 1, however, is to produce a desired change in the engine speed by controlling the air-fuel mixture via the controller of the limiter amplifier 9 is limiting, so that no engine speed compensation signal is fed via the coupling point 11 in the actuator 4 , The driver therefore hardly notice not that he drives with a device for reducing the vehicle's longitudinal dynamic instabilities.

This device has proven to be particularly advantageous in connection with diesel engines, the cause for its soft suspension in the vehicle and its characteristic vehicle longitudinal dynamics instabilities.