Design and Evaluation of a Conceptual Zero-Emission Truck Model Considering Aerodynamic Efficiency
Bibliographic record
Abstract
<div class="section abstract"><div class="htmlview paragraph">Emerging zero-emission-powertrain concepts are providing opportunities to re-shape heavy trucks for improved aerodynamic performance. To investigate the potential for energy savings through aerodynamic improvements, with a goal to inform operators and regulators of such benefits, a multi-phase project was initiated to design and evaluate aerodynamic improvements for Class 8 tractor-trailer combinations. While the focus was battery-electric and hydrogen-fuel-cell powered trucks, improvements for internal-combustion powered trucks were also examined. Previously-reported activities included a scaled-model wind-tunnel test that demonstrated the potential for up to 9% drag reduction from simple shape adaptations, with a follow-up CFD study providing guidance towards further optimization.</div><div class="htmlview paragraph">This paper presents wind-tunnel-test results using a high-fidelity 30%-scale model of a new aerodynamic tractor concept, with comparison to a conventional North American Class 8 tractor with a modern aerodynamic package and identical wheelbase. The study included testing of the new tractor concept along with individual parts such as air dams, under-body panels, grill/cooling-flow configurations, mirrors, wheel fairings, cab extenders, etc. The battery-electric variant of the new tractor provided a 16% drag reduction compared to the conventional truck model when using the same trailer configuration. When paired with a low-drag-trailer concept, the new tractor-trailer combination demonstrated up to 41% drag reduction compared to the conventional tractor with a standard box-van trailer. This configuration is shown to be nearly insensitive to crosswinds with a wind-averaged drag coefficient of 0.34. Examining additional cooling-flow configurations necessary for hydrogen-fuel-cell trucks showed up to 3% increase in drag associated with the extra cooling drag. Additionally, the new tractor-shaping concept applied to a conventional internal-combustion-powertrain arrangement generated 8% drag reduction compared to the conventional tractor.</div></div>
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".