Effects of Spark Characteristics on Engine Combustion with Gasoline and Propane
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Bibliographic record
Abstract
<div class="htmlview paragraph">This paper describes an experimental study of the effects of ignition spark characteristics on combustion behaviour in a light duty automotive engine. A prototype programmable energy ignition system was used to investigate the influence of both spark energy and the current/time profile used to deliver a given amount of energy. The engine was tested under part load conditions using a stoichiometric air/fuel ratio and relatively high levels of exhaust gas recirculation (EGR). In addition to tests with port-injected gasoline, tests were also carried out using propane (premixed upstream of the throttle) in order to investigate the possibility that improvements in the homogeneity of the mixture might influence the impact of varying the spark characteristics.</div> <div class="htmlview paragraph">The results focus upon the Coefficient of Variation of Indicated Mean Effect Pressure (COV of IMEP) and the 10% Mass Fraction Burn (MFB) duration versus concurrent measurements of the electrical energy delivered into the spark plug gap. Different spark waveforms in which current was delivered continuously during the spark produced similar reductions in the 10% MFB duration as the delivered spark energy was increased, while sparks with intermittent current delivery (multi-spark approaches) were somewhat less effective in this regard. COV levels with port injected gasoline were substantially higher than those with premixed propane when the delivered spark energy was very low, but the two fuels produced similar COV levels when the spark energy was increased. Significant differences in spark plug erosion would be expected for the various types of spark current waveforms due to differences in the integrated current required to deliver a given amount of ignition energy and the proportioning of the current between arc and glow discharge.</div>
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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 | 0.000 | 0.003 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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 it