High-efficiency hydrostatic vehicular drive system

Patent · Tue Aug 12 04:00:00 EDT 1980

OSTI ID:6769044

Hamma, K

A drive system has an engine that operates a control pump and a hydraulic variable-displacement drive pump having a control element and connected to a hydraulic motor. A servocylinder operates the control element of the drive pump and is pressurized through a control line connected to the control-pump output. A control valve is connected between the control line and the sump of the system and is connected to the hydraulic line between the motor and the drive pump to reduce pressure in the control line when the higher pressure of the line between the drive pump and the motor rises within a predetermined range. Thus it is possible with a substantially constant engine speed to produce a substantially constant output torque, with only the displacement of the pump and pressure in the lines between the pump and the motor varying by appropriate control of the control-line pressure.

• Assignee: Zahnradfabrik Friedrichshafen Ag (Germany, Federal Republic Of)
• Patent Number(s): US 4216656
• OSTI ID: 6769044
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100 -- Internal Combustion Engines
330600* -- Advanced Propulsion Systems-- Vehicle Design Factors
CONTROL EQUIPMENT
DESIGN
ENGINES
EQUIPMENT
FLOW REGULATORS
FLUID MECHANICS
HEAT ENGINES
HYDRAULICS
HYDROSTATICS
INTERNAL COMBUSTION ENGINES
MACHINE PARTS
MECHANICAL TRANSMISSIONS
MECHANICS
MOTORS
PUMPS
TORQUE
VALVES
VEHICLES