Itt Industries, Inc.

Heinz Loreck

Hans W Bleckmann

To avoid dangerous pressure decreases in antiskid systems, it is necessary to continuously monitor the operability of the electrical components. The present invention ensures maximum reliablity and a simple circuit configuration. Electrical signals are generated during the period of time in which a pressure decrease occurs and/or by the speed of pressure decrease at each wheel of a vehicle axis and are subtracted from one another. If the absolute value of the difference reaches a limiting value, the disturbed part of the system will be prevented from causing a further pressure decrease.

Method and a device for monitoring an antiskid system

It is known that an output valve providing a pressure decrease in a wheel brake cylinder can be controlled by a pulse train which is variable in response to the acceleration or deceleration of the associated wheel. A disadvantage of such an arrangement is that a wheel at standstill will not be able--under certain circumstances--to accelerate again during a control cycle. Additionally, the wheel brake cylinder pressure may have been decreased to such an extent that the wheel will neither continue to decelerate, or accelerate sufficiently. According to the present invention the control behavior is improved in these critical cases by generating pulses proportional to wheel acceleration and to transmit an opening signal to the outlet valve upon cessation of the accelerating pulses. The opening signal is immediately switched off as soon as the acceleration pulses occur again.

Method and a circuit for controlling the pressure in wheel brake

Converters are known where input pulses are coupled to a detector stage via an adding device and a first integrating register. The detector stage provides an output signal relative to threshold values which increases, keep constant or reduce the contents of a second integrating register. The contents of the second register are coupled to the minus input of the adding device. The time variation of the input pulses may be coupled from the detector stage. According to the present invention the dynamic behavior, stability and suppression of disturbances is improved by differentiating the input pulse train, coupling this pulse train to the detector stage and to integrate the output of the detector stage with the integration factor being constantly adjusted to the output signal of the detector stage.

Method and circuit for the conversion of variable physical quantities

It is known that a vehicle speed reference signal suitable for slip control can be obtained by fully releasing the braking force at one or more vehicle wheels intermittently and to obtain the true vehicle speed from the signal provided by the free-rotating wheels. However, this technique results in the stopping distance of the vehicle being longer than desired since the braking effectiveness is considerably reduced. To avoid this disadvantage, the present invention compares a speed reference signal cyclically with the instantaneous velocity signals of the wheels and to weight the comparison result dependent on whether the instantaneous velocity signal comes from a driven wheel or a non-driven wheel. The weighted comparison result provides a correcting factor for the speed reference signal.

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Moedling, Austria

Heinz Loreck