Ignition by Shielded Glow Plug in Natural Gas Fueled Direct Injection Engines
Bibliographic record
Abstract
Injected natural gas requires some form of ignition assist in order to ignite in the time available in a diesel engine combustion chamber. A glow plug — a heated surface — is one form of ignition assist. Ignition by glow plug results in a single site of ignition from which the flame must propagate to other jets in the ignition pattern. The goal of this work was to determine what factors affect how the flame propagates from this initial ignition site to the remaining unburned mixture. The combustion of natural gas jets under diesel engine conditions was studied over a range of temperatures with a glow plug shield using a CFR engine as a rapid compression device. The results showed that of all the factors considered it is the inter-related geometries of the injection pattern, combustion chamber, and glow plug shield that are most dominant in controlling combustion rates and fuel utilization, because those factors determine the distribution of fuel in the combustion chamber. Ignition of adjacent gas jets requires a flammable path between jets, which is achieved: 1) through mixing between the entrainment regions of adjacent jets and 2) through mixing along the cylinder wall of adjacent jets that are spreading along the wall. Ignition by either of both of these pathways can provide high fuel utilization and combustion rates and low combustion variability. Autoignition of an adjacent jet due to heat release from ignition of the first jet was not observed in these experiments with two jets.
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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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".