An Experimental Investigation of HCCI Combustion Stability Using N-Heptane
Bibliographic record
Abstract
In this paper, cyclic variations in the combustion process of a single-cylinder HCCI engine operated with n-heptane were measured over a range of intake air temperatures and pressures, compression ratios, air/fuel ratios, and exhaust gas recirculation (EGR) rates. The operating conditions produced a wide range of combustion timings from overly advanced combustion where knocking occurred to retarded combustion where incomplete combustion was detected. Cycle-to-cycle variations were shown to depend strongly on the crank angle phasing of 50% heat release and fuel flow rate. Combustion instability increased significantly with retarded combustion phasing especially when the fuel flow rate was low. Retarded combustion phasing can be tolerated when the fuel flow rate is high. It was also concluded that the cyclic variations in imep are primarily due to the variations in the total heat released from cycle-to-cycle. The completeness of the combustion process in one cycle affects the in-cylinder conditions and resultant heat release in the next engine cycle.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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".