Drive-dynamometer system
First Claim
1. In a test stand for vehicle engines, means supporting an engine to be tested, and a hydrostatic system comprising a fixed displacement motor connected to the engine crankshaft and a variable displacement pump spaced from said motor and having motive means for driving it, said system being a closed hydraulic loop system connecting said motor and pump whereby the engine may be selectively cold-tested or hot-tested, the motor during hot-testing acting as a pump and the pump acting as a motor, means for adjusting the displacement of said pump, and a control loop system for said pump adjusting means to simulate different load or inertia conditions.
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Accused Products
Abstract
A drive-dynamometer system particularly adapted for automated testing of parts such as vehicle engines. The dynamometer is a hydrostatic system having a fixed displacement motor connected to, and a variable displacement pump spaced from the part being tested, the pump having motor means for driving it. The system has a closed hydraulic loop connecting the motor and the pump whereby the engine may be selectively cold-tested or hot-tested, the motor during hot-testing acting as a pump and the pump acting as a motor which therefore drives its motor means. Preferably, this comprises a synchronous electric motor, which, when acting as a generator, creates useful electric power for the plant in which the unit is installed. Means are provided for adjusting the displacement of the pump, and a control loop system is provided for the pump adjusting means to simulate different load or inertia conditions. The fixed displacement motor has two motive connections, and a device is preferably provided for sensing the pressure differential between said connections to indicate positive or negative torque.
25 Citations
13 Claims
- 1. In a test stand for vehicle engines, means supporting an engine to be tested, and a hydrostatic system comprising a fixed displacement motor connected to the engine crankshaft and a variable displacement pump spaced from said motor and having motive means for driving it, said system being a closed hydraulic loop system connecting said motor and pump whereby the engine may be selectively cold-tested or hot-tested, the motor during hot-testing acting as a pump and the pump acting as a motor, means for adjusting the displacement of said pump, and a control loop system for said pump adjusting means to simulate different load or inertia conditions.
- 8. In a hydrostatic drive-dynamometer system for hot-testing or cold-testing vehicle engines, a fixed displacement motor connected to the engine crankshaft and having two main motive connections, a variable displacement pump spaced from said motor and having motive means for driving it, said system being a closed hydraulic loop system unobstructed in either direction throughout its extent connecting said motor and pump whereby the engine may be selectively cold-tested or hot-tested, the motor during hot-testing acting as a pump and the pump acting as a motor, a servo controller for said variable displacement pump, a programmer connected to said servo controller for commanding engine speed, a speed feedback sensor connecting said fixed displacement motor with said servo controller, a throttle servo connected to the engine carbureto, a connection between said programmer and said throttle servo, and a pressure differential sensor connected to the motive connections of said fixed displacement motor for indicating positive or negative torque.
- 10. In a test stand for vehicle engines, means supporting an engine to be tested, and a hydrostatic system comprising a fixed displacement motor unit and a variable displacement pump unit, one of said units being connected to the engine crankshaft and the other spaced from the first unit and having motive means for driving it, said system being a closed hydraulic loop system connecting said motor and pump whereby the engine may be selectively cold-tested or hot-tested, the motor during hot-testing acting as a pump and the pump acting as a motor, means for adjusting the displacement of said pump, and a control loop system for said pump adjusting means to simulate different load or inertia conditions.
- 12. In a hydrostatic drive-dynamometer system for hot-testing or cold-testing vehicle engines, a first fluid unit connected to the engine crankshaft, a second fluid unit spaced from said first fluid unit, one of said units comprising a fixed displacement motor having two main motive connections, the other unit comprising a variable displacement pump spaced from the motor and having motive means for driving it, said system being a closed hydraulic loop system unobstructed in either direction throughout its extent connecting said motor and pump whereby the engine may be selectively hot-tested or cold-tested, the motor, during hot-testing acting as a pump and the pump acting as a motor, a servo controller for said variable displacement pump, a programmer connected to said servo controller for commanding engine speed, a speed feedback sensor connecting said fixed displacement motor with said servo controller, a throttle servo connected to the engine carburetor, a connection between said programmer and said throttle servo, and a pressure differential sensor connected to the motive connections of said fixed displacement motor for indicating positive or negative torque.
Specification