Mannesmann Rexroth Corporation

Volkswagen Ag

Frank Metzner

Heinrich W Nikolaus

Peter Reinhardt

Rolf Kordak

Hermann Deutsch

Frank Meyer-Hessing

For a compact arrangement of a relatively large number of cylinders, the specification discloses a V-type engine having first and second rows of cylinders which are arranged relative to each other so as to form a V-shape, with a third row of cylinders located between the first and second rows and a fourth row located outside the V-space between the first and second rows, the third and fourth rows likewise forming a V-shape between them, and all cylinders of the internal combustion engine being connected to the same crankshaft.

V-type internal combustion engine arrangement

A hydrostatic drive system consists respectively of an adjustable primary and secondary unit which are connected together via a conduit train with impressed pressure. The volume flow of the primary unit is regulated in dependence upon the impressed pressure and the volume flow of the secondary unit as a function of the speed. To avoid pronounced dropping of the impressed pressure the power of the secondary unit is limited. For this purpose a circuit is provided in which the volume flows of the primary and secondary units are compared. The power limitation intervenes when the volume flow of the secondary unit exceeds the volume flow of the primary unit.

Hydrostatic drive system

The torque of a hydraulic machine is dependent of the fluid pressure delivered to the machine and is further dependent of the adjustment of its volume of through-put. In response to a load coupled to the machine, a speed results which is controlled by a speed control system acting on the adjusting system of the hydraulic machine. According to the invention, an electro hydraulic speed control comprises a pair of control circuits which are connected to, but operate independent of each other. Thus the electrical control circuit produces a control signal y.sub.e1 from the difference of the actual value and the desired value of the speed for adjusting a hydraulic restricting means which produces a hydraulic pressure signal p.sub.st in the hydraulic control circuit which pressure signal is compared with a hydraulic reference signal p.sub.o to produce a differential pressure signal p.sub.o -p.sub.st which is applied to the adjusting cylinder of the hydraulic machine. The control system thus comprises two circuits, i.e. an electrical speed control circuit and a hydraulic pressure control circuit resulting in optimizing the control operation.

Hydraulic drive system

Improved control of a hyrostatic drive machine at very small speeds of rotation. The rotation speed control signal in the creep rotation speed region is modified in dependence upon the actual value of the rotation angle and possibly the efficiency characteristic diagram so as to produce a regulated constant torque.

Rotation angle dependent correction of speed control signal in low-speed

A secondarily controlled hydrostatic machine with variable volume is connected to a line with impressed system pressure which is fed by a primary unit. By switching over the primary unit the secondary unit is subjected to a displacement amount which results in as large as possible a pivot angle of the secondary unit to obtain the highest possible efficiency. The switching over takes place in dependence upon an upper and lower switching point corresponding to the desired pivot angle range of the secondary unit.

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Wolfsburg, Germany

Frank Metzner