Transmission Torque Control for Accurate Engine Behavior Reproduction
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Solution Overview
Problem
The existing transmission testing devices using drive dynamometers face challenges in accurately reproducing the behavior of actual engines, particularly in the high frequency band due to noise amplification in the command values generated by inertia compensation.
Innovation Solution
A transmission testing device configuration that includes a drive dynamometer connected to the input shaft, an absorption dynamometer connected to the output shaft, a shaft torque detection unit, and a control unit that generates shaft torque and engine torque correction values using specific transfer functions to accurately control the drive dynamometer, simulating the behavior of an actual engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inertia compensation is performed by generating a command value using differentiation of the difference value between drive dynamometer inertia and actual engine inertia, then the shaft torque values can match between the drive dynamometer and actual engine, but noise is amplified particularly in the high frequency band, making it difficult to accurately reproduce engine behavior
Solution Approach 1:
A correction value generation unit is introduced as an intermediary component that receives both the shaft torque value and engine torque input value, processes them through transfer functions, and generates correction values. This intermediary unit filters out high-frequency noise while maintaining the essential torque characteristics, thereby resolving the contradiction between measurement precision and noise amplification.
Solution Approach 2:
The system implements feedback by using the detected shaft torque value to generate a shaft torque correction value, and by using the engine torque input value to generate an engine torque correction value. These correction values are fed back to adjust the drive dynamometer's torque command, creating a closed-loop control system that accurately reproduces engine behavior without amplifying noise.
2Adaptability or versatility
If a drive dynamometer is used to simulate actual engine behavior, then engine testing can be performed without an actual engine, but the difference in inertia between the drive dynamometer and actual engine causes mismatch in shaft torque values
Solution Approach 1:
The system changes the torque command parameters by adding correction values to the base torque command. The shaft torque correction value and engine torque correction value are calculated based on transfer functions that account for the inertia difference between the drive dynamometer and actual engine, thereby adjusting the parameters to achieve accurate shaft torque matching while maintaining the ability to test without an actual engine.
Data Source
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AI summary
Provide is a transmission testing device that can highly accurately reproduce behavior of an actual engine. The present invention includes a drive dynamometer DM1 that is connected to an input shaft 11a of a transmission 11, absorption dynamometers DM2 and DM3 that are connected to output shafts of the transmission 11, a shaft torque detection unit 12 that detects a shaft torque value generated at the input shaft 11a of the transmission 11, and a control unit 13 that controls the drive dynamometer DM1. The control unit 13 uses the shaft torque value detected by the shaft torque detection unit 12 to generate a shaft torque correction value for the drive dynamometer DM1, receives an engine torque input value and uses the received engine torque input value to generate an engine torque correction value for the drive dynamometer DM1, and controls the drive dynamometer DM1 on the basis of a torque command value generated from the shaft torque correction value and the engine torque correction value.