Robert Boschgmbh

Saab-scania Ab

Franz Maurer

Werner Stumpe

Eberhard Weiss

Konrad Eckert

Peter Zieher

Ingolf Grauel

Helmut Domann

Rainer Wirtz

Egbert Muller

Manfred Stahl

Hakan Samuelson

Erich Jung

Eric Thoms

A multiple-circuit brake system for motor vehicles in which a multiple-circuit braking value transducer is embodied partially electrically and partially as a pneumatic control valve and is intended for triggering pressure control valves, the wheel brake cylinders being disposed following these pressure control valves. One pressure-medium reservoir is associated with each pressure control valve, and the controlling energy for each of these pressure control valves is drawn from the pressure-medium reservoir associated with that valve. In the pneumatic brake circuit (I), a further pressure-medium reservoir is provided preceding the braking value transducer, as a result of which it is possible, with the aid of two-way check valves, to actuate the wheel brake cylinders with the pneumatic brake circuit (I) whenever the electrical brake circuits (II, III) have failed.

Multiple-circuit brake system

A brake control system has a controller (52, 53, 54) including hysteresis. To prevent over-shoot of control operation if a comparison between actual braking pressure (P.sub.act) and commanded pressure (P.sub.com) is applied to control valves which, for example, operate pneumatically, so that the brakes will not instantaneously respond, a difference pressure threshold (.DELTA.P.sub.G) is determined and, when the difference pressure level is passed by the difference pressure signal, the valves are controlled to operate in pulse operation, in which each pressure pulse (T.sub.E) is followed by a quieting or pressure-OFF time (T.sub.BER). The pulse sequence and the timing of pulses and pulse gaps is controllable in accordance with pressure levels, operating parameters, pressure difference levels and the like.

Method and system for electrically controlling braking of a vehicle

Brake force regulating system

Optimum fuel consumption in an internal combustion engine driving a hydrostatic transmission having a continuously variable gear ratio is achieved by first applying the signal derived from the gas pedal directly to the transmission ratio regulator and, secondly, by controlling the fuel consumption of the engine in response to the gas pedal signal as follows: first, the signal from the gas pedal is multiplied by a signal signifying the output speed of the transmission. The so-formed desired power signal is applied to a storage which furnishes a desired engine speed signal in response thereto. The desired speed signal is compared to the actual engine speed and the resulting error signal, after amplification and integration, is applied to a unit controlling the fuel supply of the engine.

System for optimizing the fuel consumption of an internal combustion

To turn a thyristor, particularly a high-voltage thyristor, ON, and to connect the thyristor and the utilization circuit to a power source, a charge capacitor is connected to a charging circuit to charge the capacitor when the thyristor is blocked or in OFF state. A controlled switch, typically a transistor 20, is connected to the charge capacitor 19 and connects the charge capacitor to the gate electrode of the thyristor, when the controlled switch is turned ON; a control circuit is connected to the controlled switch which includes an opto-coupler 28 to control its conduction. Preferably, a threshold sensitive element such as a Zener diode 25, or a four-layer diode 30, is included in the controlled switch transistor base circuit to provide for sharp turn-on characteristics. Since the conduction characteristics of the controlled switching transistor 20 will depend on the charge state of the capacitor 19, the controlled switching transistor will be conductive only when the capacitor has a sufficiently high charge for reliable firing of the thyristor.

Switching circuit for high-voltage thyristors

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Schwieberdingen, Germany

Franz Maurer