Test Bench Adapter Flange Inertia Tuning for Engine Simulation
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Solution Overview
Problem
Current engine test bench systems are insufficient in reproducing drive train simulations beyond 8-10 Hz, failing to accurately represent the real vehicle-specific combustion and transient behavior of internal combustion engines, particularly in capturing cyclical irregularities and excited frequencies up to 40 Hz.
Innovation Solution
The test stand arrangement is designed with a selected mass and moment of inertia for the adapter flange and electric machine to set the natural frequency between 10 Hz and 100 Hz, utilizing a parallel joint shaft and a 3-phase-fed electric machine with low inertia and high torque-to-moment ratio, enabling realistic simulation of combustion shocks and drive train vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the natural frequency of the test bench is set above 100 Hz with a resonance control unit to suppress resonance, then the test bench can operate at higher frequencies, but the system complexity increases due to the resonance control unit and the ability to accurately represent drive train vibrations up to 40 Hz deteriorates
Solution Approach 1:
The patent changes the natural frequency parameter of the test bench from above 100 Hz to between 10 Hz and 100 Hz (preferably 20 Hz to 60 Hz) by adjusting the moment of inertia of the adapter flange. This parameter change eliminates the need for resonance control units while enabling accurate representation of drive train vibrations up to 40 Hz, thus reducing system complexity while maintaining or improving frequency response capability.
2Reliability
If the moment of inertia of the adapter flange is increased to set the natural frequency between idle and partial load frequencies, then the natural frequency moves to the engine operating range, but the acceleration capability of the system may be reduced
Solution Approach 1:
The patent carefully adjusts the moment of inertia of the adapter flange to achieve a natural frequency between 10 Hz and 100 Hz (preferably 20 Hz to 60 Hz), which is in the engine operating range. This parameter optimization enables accurate representation of combustion shocks and drive train vibrations while the electric machine's high torque-to-inertia ratio compensates for any reduction in acceleration capability, maintaining overall system performance.
Solution Approach 2:
The patent uses an electric machine with the largest possible ratio of torque to moment of inertia to provide high acceleration capability despite the increased moment of inertia of the adapter flange. This allows the system to quickly reach target operating conditions and frequencies, compensating for the slower response that would result from the higher natural frequency setting.
3Speed
If the electric machine is designed with the lowest possible moment of inertia and largest torque-to-moment ratio, then the acceleration capability is improved, but the device complexity increases
Solution Approach 1:
The patent specifies that the electric machine should have the lowest possible moment of inertia and the largest possible ratio of torque to moment of inertia. This parameter optimization enables high acceleration capability for driving and loading the test object. The solution accepts increased electric machine design complexity as necessary to achieve the required dynamic performance for accurate drive train simulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for precise simulation of real vehicle behavior, including hybrid start/stop operations and drive train vibrations up to 40 Hz, facilitating efficient development and calibration tasks without the need for prototypes, enabling earlier coordination of development goals and reducing testing time and costs.
Implementation Method 1
the mass and the moment of inertia of the adapter flange are selected in such a way that the natural frequency of the system consisting of the test object, adapter flange, connecting shaft and electric machine for driving and / or loading the test object is between the idle frequency and a partial load frequency of the test object
Implementation Method 2
an electric machine (4) for driving and / or loading the test object (1), wherein the arrangement has a constant, predetermined moment of inertia from the connecting shaft (2) and the drive and loading machine (4)
Implementation Method 3
The connecting shaft is advantageously designed as a parallel joint shaft
Implementation Method 4
the electric machine for driving and / or loading the test object has the largest possible ratio of torque to moment of inertia. The two features mentioned are responsible for ensuring that the electric machine has a high acceleration (braking) capability
Data Source
AI summary
A test bench arrangement includes an electric machine (4) for driving and/or loading a test specimen (1) and is connected to it by a connecting shaft (2) with an adapter flange (3). In order to establish the connection between the powertrain and vehicle simulation and the real vehicle-specific combustion and transient behavior of the engine, the arrangement consisting of the connecting shaft (2) and the drive and load machine (4) has a constant, predetermined moment of inertia, and the mass and moment of inertia of the adapter flange (3) are selected such that the natural frequency of the system consisting of the test specimen (1), adapter flange (3), connecting shaft (2), and electric machine (4) for driving and/or loading the test specimen (1) lies between the no-load frequency and a partial-load frequency of the test specimen (1).