Analysis of emissions from urban transit buses in real life conditions
Bibliographic record
Abstract
Due to limitations in instrumentation for testing of emissions, heavy–duty engines are commonly tested on engine dynamometers using modal or transient cycles. There is an urgent need to verify these procedures in real life situations. This paper presents the analysis of the results of testing of emissions from urban transit buses, conducted by Emissions Research and Measurement Division (ERMD) with collaboration of Instituto Colombiano del Petroleo ECOPETROL in Bogota, Colombia. Testing was conducted in real road conditions, using a portable dilution system designed and manufactured by the ERMD, on 15 randomly selected urban buses, using a specially designed road cycle. ECOPETROL, the main Colombian petroleum producer, had lowered the sulfur content from 3000 ppm to 1000 ppm in the fuel supplied for Bogota urban transit as a means to reduce emissions of secondary particulates. The expected trends were actually observed, but there were large test–to–test differences. It was concluded that testing should be confirmed on an engine dynamometer at the ERMD facility in Ottawa, Canada.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".