A Novel Semi-active Magnetorheological Bushing Design for Variable Displacement Engines
Bibliographic record
Abstract
This study introduces the concept of smart materials, namely magnetorheological (MR) fluids, to the design of automotive engine isolation systems. Hydraulic bushings and mounts are widely used in the automobile industry to isolate the engine and chassis from each other. The simplicity and low cost associated with these types of bushing, in addition to their dual frequency response characteristics, are the main reasons for their industrial popularity. Recently with the introduction of variable displacement engines (VDE), the conventional bushings have reached their performance limits. A more versatile isolator is therefore required to handle the additional vibration and disturbances in VDE, associated with the change in the engine displacement whenever the automobile does not use its full displacement capacity for maintaining the desired speed. The realization is that the appropriate isolator should be half as stiff in the operating frequency range of the three cylinder mode of the engine. In addition, in the full cylinder mode the isolator must maintain the performance levels comparable to existing conventional products. This study introduces a cost-effective semi-active bushing for the VDE isolation problem. After a study of the VDE systems, different modes of engine performances in those systems are discussed, and the ideal isolator features for this type of engine are identified. The hydraulic bushing frequency response is then obtained experimentally. Based on the experimental results, a simple semi-active bushing proof-of-concept design is developed and tested, which utilizes a short inertia track to satisfy the soft isolator requirement in VDE mode. A mathematical model of the semi-active system is generated, and its validity is verified experimentally. The damping requirement of this semi-active isolator is produced by utilizing a MR compliance chamber. This innovative solution reduces the amount of expensive MR fluid requirements of the bushing. The experimental results on the semi-active bushing system, using a magnetic shaker, show the merit of the system for the VDE application.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".