| Zugriffsnummer | 31337 |
| Dokumenttyp | Zeitschriftenartikel |
| Sprache | Englisch |
| Titel | Calibration-free, high-speed, in-cylinder laser absorption sensor for cycle-resolved, absolute H2O measurements in a production IC engine |
| Autor(in); Institution |
Witzel, Oliver; 3.2, Gasanalytik und Zustandsverhalten, PTB-Braunschweig
Klein, Alexander; 3.2, Gasanalytik und Zustandsverhalten, PTB-Braunschweig
Meffert, C.; Universität Duisburg-Essen, Duisburg, GERMANY
Schulz, C.; Universität Duisburg-Essen, Duisburg, GERMANY
Kaiser, S.A.; Universität Duisburg-Essen, Duisburg, GERMANY
Ebert, Volker; 3.2, Gasanalytik und Zustandsverhalten, PTB-Braunschweig
|
| Quelle/Jahr | Proceedings of the Combustion Institute: 35 (2014), 3, 3653 - 3661 |
| ISSN | 1540-7489 |
| DOI | |
| Verlag | Amsterdam [u.a.]: Elsevier |
| Freie Schlagworte | IC engine ; residual gas ; spectroscopy ; tunable diode laser absorption ; combustion diagnostics |
| Zusammenfassung | The performance of a hygrometer based on calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS) for in-cylinder H2O measurements is demonstrated in a nearly unmodified production internal combustion engine. The H2O concentration is a proxy for the residual -gas fraction remaining in the cylinder after intake-valve closure. One challenge for in-cylinder measurements, especially in multi-cylinder engines, is to obtain optical access to the combustion chamber. The measurements here were performed in the flywheel-side cylinder of a four-cylinder engine with small access ports that were previously designed for endoscopic imaging. Due to their position these ports prohibit the usual collinear arrangement of the optical elements typical for line-of-sight measurement techniques. Therefore, we developed a new “angled” fiber-optical interface, which allows a trans-illumination of the engine at a 90° angle. The optical fiber interface uses a scattering target inside the combustion chamber with its 84 mm bore achieving an absorption length of about 70 mm. With this arrangement, crank-angle resolved measurements of the H2O concentration during early compression could be monitored realized with a temporal resolution of 250 µs and a H2O precision detection limit of 0.074 vol.%. This allows detailed analysis of single engine cycles as needed for residual -gas investigations. Measurements were performed with over a range of various loads (25 – 100 Nm) and speeds (1400 – 370650 rpm) were performed, over which the residual -gas fraction was expected to vary significantly. We measured H2O concentrations were measured between 3.3 and 5.0 vol.%. The results were compared with a simple model of residual gas content and were found to agree within the combined uncertainty of both methods, which gives an indication that dTDLAS can be used to validate more complex engine models beyond what is possible by pressure-trace analysis. |
Zitierung
Witzel, O., Klein, A., Meffert, C., Schulz, C., Kaiser, S., & Ebert, V. (2014). Calibration-free, high-speed, in-cylinder laser absorption sensor for cycle-resolved, absolute H₂O measurements in a production IC engine. Proceedings of the Combustion Institute, 35(3), 3653–3661. https://doi.org/10.1016/j.proci.2014.06.038