Determination of the Start and End of Combustion in a Direct Injection Diesel Engine Using the Apparent Heat Release Rate
Bibliographic record
Abstract
The combustion duration in an internal combustion engine is the period bounded by the engine crank angles known as the start of combustion (SOC) and end of combustion (EOC), respectively. This period is essential in analysis of combustion for the such as the production of exhaust emissions. For compression-ignition engines, such as diesel engines, several approaches were developed in order to approximate the crank angle for the start of combustion. These approaches utilized the curves of measured in-cylinder pressures and determining by inspection the crank angle where the slope is steep following a minimum value, indicating that combustion has begun. These pressure data may also be utilized together with the corresponding cylinder volumes to generate the apparent heat release rate (AHRR), which shows the trend of heat transfer of the gases enclosed in the engine cylinder. The start of combustion is then determined at the point where the value of the AHRR is minimum and followed by a rapid increase in value, whereas the EOC is at the crank angle where the AHRR attains a flat slope prior to the exhaust stroke of the engine. To verify the location of the SOC, injection line pressures and fuel injection timing are also used. This method was applied in an engine test bench using a four-cylinder common-rail direct injection diesel engine with a pressure transducer installed in the first cylinder. Injector line pressures and fuel injector voltage signals per engine cycle were also recorded and plotted. By analyzing the trends of this curves in line with the generated AHRR curves, the SOC may be readily determined.
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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 | 0.000 | 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 | 0.000 | 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 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".