Robert Boschgmbh

Paul Luis Hernandez Ladera

Michael Mast

Steffen Mutschler

Erich Ilk

Dietmar Bantle

Carola Spielvogel

Franz Werner

Olivier Krajka

A hydrostatic propulsion drive for a vehicle is disclosed including an electronic control unit and a hydrostatic transmission having a hydraulic pump with an adjustable swept volume and a hydraulic motor with an adjustable swept volume, the hydraulic pump being arranged in a closed hydraulic circuit. The swept volumes of the hydraulic pump and the hydraulic motor are changeable in accordance with a correction factor which is stored in a characteristic diagram and is dependent on the rotational speed and the drive torque of the hydraulic motor, the operating pressure at the hydraulic motor being increased if the correction factor is used. Due to the increased operating pressure, flow-induced pressure drops are reduced by way of volumetric flows, and leakage flows via gaps between moving parts of the hydraulic pump and the hydraulic motor are kept large enough to avoid excessive friction and loss of efficiency.

Hydrostatic propulsion drive for a vehicle

A hydrostatic drive includes a diesel engine and a hydrostatic adjustable machine which supplies multiple consumers in normal operation as a pump. The machine has a pressure/flow regulator to which is communicated, according to the load-sensing principle, the highest load pressure of the consumers, in particular when the machine is operated as a pump. In order to realize a start/stop function of the diesel engine, a previously charged high-pressure reservoir supplies the hydrostatic machine, which then acts as a starter motor for the diesel engine. In order to switch from pump to starter motor, the hydro-machine is adjusted over zero. In order for this switch to take place quickly and reliably, the pressure/flow regulator is deactivated by means of a switching valve and the adjustment device is supplied with an adjustment pressure medium via the switching valve, which medium is taken from the high-pressure reservoir or from an auxiliary reservoir.

Hydrostatic drive

A hydrostatic drive includes a hydraulic machine, a hydraulic adjusting device, a high-pressure accumulator, an accumulator-closing valve, and an electronic control unit. The hydraulic machine has a swept volume that is adjustable via the hydraulic adjusting device from a maximum positive swept volume to a maximum negative swept volume via a zero swept volume. The hydraulic machine is operated as a pump with positive swept volume and as a motor with negative swept volume. The high-pressure accumulator supplies the hydraulic machine with pressure medium for operation as a motor via a pressure line. The accumulator-closing valve has a first position and a second position and is arranged in the pressure line. A fluidic connection from the high-pressure accumulator to the hydraulic machine is open in the first position and closed in the second position. The accumulator-closing valve is actuated in accordance with signals from the electronic control unit.

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Elchingen, Germany

Paul Luis Hernandez Ladera