Engine Test Apparatus Inertia Compensation via Shaft Speed
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Solution Overview
Problem
Conventional engine test apparatuses face limitations in inertia compensation frequency range, leading to inaccurate measurement of engine characteristics due to resonance issues when using dynamometer rotation speed for control.
Innovation Solution
An engine test apparatus that measures the rotation speed of the engine's output shaft and uses this data for inertia compensation control, allowing for a broader frequency range and reducing resonance by converting engine rotation behavior into torque, thereby accurately controlling the dynamometer operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dynamometer rotation speed is used for inertia compensation control, then the control system can operate the engine in an unloaded state, but the frequency range for inertia compensation is limited due to antiresonance points
Solution Approach 1:
The patent introduces an intermediary element - a phase lead compensation process - to mediate between the dynamometer rotation speed signal and the torque current command. This phase lead compensation acts as a mediator that corrects the phase advance caused by antiresonance, allowing the system to maintain reliable inertia compensation across a broader frequency range including the previously problematic 100 Hz region.
2Ease of operation
If the dynamometer rotation speed is used for inertia compensation control, then the engine can be controlled in an unloaded state, but resonance occurs at resonance points due to phase advance
Solution Approach 1:
The patent applies preliminary anti-action by introducing a phase lead compensation process that anticipates and counteracts the phase advance problem before it causes resonance. The compensation is built into the control system in advance, allowing the engine to operate in an unloaded state without experiencing resonance instability at resonance points.
3Adaptability or versatility
If the rotation speed of the output shaft of the engine is used for inertia compensation control, then the frequency range for inertia compensation is extended, but additional measurement devices are required
Solution Approach 1:
The patent makes the speed measuring device universal by having it serve multiple functions: it measures the rotation speed of the engine's output shaft for inertia compensation control, and can also provide rotation speed data for other control purposes. This multi-functionality extends the frequency range for inertia compensation without proportionally increasing device complexity.
Data Source
AI summary
An engine test apparatus includes a dynamometer connected to an engine through a shaft, and a control device configured to control operations of the engine and the dynamometer, and the engine test apparatus further includes a speed measuring device configured to measure a rotation speed of the output shaft of the engine and transmit the rotation speed to the control device the control device includes an engine control unit configured to control operation of the engine, and a dynamometer control unit configured to control operation of the dynamometer, the dynamometer control unit uses the rotation speed transmitted from the speed measuring device to generate a torque current command corresponding to a torque value to be generated by the dynamometer, in order to operate the engine controlled to be operated by the engine control unit in an unloaded state as if the shaft and the dynamometer are not connected.