Test bench

A test stand is a device or a device with a technical article may be tested for its properties reproducible. At a bench next to a part of the mechanical design for accommodating the test item also generate the corresponding sensor and control the properties and can log readings.

  • 3.1 control
  • 3.2 multi-machine control (depending on test set )
  • 3.3 Machine Control
  • 3.4 test machine

Survey

There are two different types of test, depending on the area of ​​responsibility:

  • Development test
  • EOL test (end-of - line test stand )

Development test

In R & D test fully automatic previously stored in the vehicle route profiles, synthetic line profiles or stage testing ( table with different load levels) can be driven. The goal is abzufahren on the test bench in no time the load in the vehicle or other relevant test scenarios.

Development test benches can in turn be divided into:

  • Endurance test bench ( components are tested over a defined cycle life)
  • Emissions test / exhaust test ( test of an internal combustion engine to the exhaust gas values ​​or the compliance with legal exhaust regulations )
  • Air test (in the climatic chamber, the behavior of the specimen in heat and cold, moisture tested if necessary )
  • Vibration test bench / strength test ( testing the mechanical strength due to vibration and other mechanical stress)
  • Wind tunnel altitude test ( testing of aircraft engines )

EOL test (end-of - line test stand )

This includes test benches in the manufacturing, test the newly built specimens to function at the end of the manufacturing process. They are used for quality assurance and have received its English name because the test stands are also usually physically right at the end of assembly or production lines.

Assignment after specimens

In addition to the breakdown by area of ​​responsibility, the test benches can be distinguished even after the specimens.

  • Engine test bench / dynamometer ( electrical, hydraulic, or internal combustion engines are tested or measured. Besides the engine characteristics such as torque and power more parameters are determined and the compliance with the specified parameters (efficiency ) tested, for example, and possibly optimized)
  • Gear Watch: The transmission or the rear axle on an electric drive machine ( Substitutes the internal combustion engine) and electric. Wheeled machines ( Substituting the street) operated. Depending on the drive there 3E test stands ( rear or front axle ) and 5E- test stands ( four wheel drive ).
  • Chassis dynamometer / chassis dynamometer ( All vehicles running on a dedicated drive roller and it can be simulated driving cycles of the vehicle. The overall properties, including the losses of the drive train such as gears, drive shaft and bearing with measured are. On a dynamometer are usually also the homologation (approval tests ) carried out including exhaust measurements.
  • Aggregate test ( brake tester, pump test bench )
  • Engine test ( testing of aircraft engines )

Generally

There are different versions of the types listed, and very often it is also about combinations of different types. With the exception of the dynamometer in common is that the candidate is rigidly connected to a power brake ( Water brake, eddy current brake) or a corresponding drive. Accelerated whenever needed ( e.g., a DC motor operates as an electric motor ) or brake (for example, to absorb a direct current machine, the motor power and works as a brake ) of the drive motor, whereby continuously the torque, speed and other engine parameters are measured. From these, the engine power can be calculated.

Operation

Control

The test is usually called by a real-time capable computer, even automation system controlled.

  • This gives the control system before the setpoints (speed and / or the counter-torque to brake or to the engine and other sizes ).
  • The resulting variables as responses of the DUT (engine, transmission, etc.) receives the automation system of measuring sensors of the test rig ( torque, speed, temperature, pressure, flow, etc.).
  • The entire speed range of the concerned test specimen is measured in this way.
  • The mean values ​​and the measured values ​​of the test specimen are shown graphically on the computer and stored for later analysis.
  • Almost all of the characteristics of a specimen can be logged and monitored.

Multi-machine control (depending on test set )

This has to regulate the task, the target values ​​and then prescribes the individual machine controllers whose nominal sizes. Here, the laws of the control technology depending on the test setup must (eg the gearbox, with a prime mover and two loading machines, a decoupled multi-machine control is required so that the mechanical system from the test bed behaves almost the same as the mechanical system of the vehicle )

Machine control

The engine controller receives the setpoints and converts them into control variables for electric actuators. These are nowadays mostly IGBTs, then the electrical output variable. Current out the machines.

Test machine

These are mostly

  • Electric motors Asynchronous (most common)
  • Synchronous motors ( in highly dynamic test benches and those with very little space for the electric motors )
  • DC motors ( due to increased maintenance only rarely in new projects )
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