Challenging requirements for modern large engines regarding power output, fuel consumption, and emissions can only be achieved with carefully adapted combustion systems. With the improvement of simulation methods simulation work is playing a more and more important role for the engine development. Due to their simplicity and short computing time, one-dimensional and zero-dimensional calculation methods are widely applied for the engine cycle simulation and optimization. While the gas dynamic processes in the intake and exhaust systems can already be simulated with sufficient precision, it still represents a considerable difficulty to predict the combustion process exactly. In this contribution, an empirical combustion model for large prechamber gas engines is presented, which was evolved based on measurements on a single cylinder research engine using the design of experiment method. The combustion process in prechamber gas engines is investigated and reproduced successfully by means of a double-vibe function. The mathematical relationship between the engine operating parameters and the parameters of the double-vibe function was determined as a transfer model on the base of comprehensive measurements. The effects of engine operating parameters, e.g., boost pressure, charge temperature, ignition timing, and air/fuel ratio on the combustion process are taken into account in the transfer model. After adding modification functions, the model can be applied to gas engines operated with various gas fuels taking into account the actual air humidity. Comprehensive verifications were conducted on a single-cylinder engine as well as on full-scale engines. With the combination of the combustion model and a gas exchange simulation model the engine performance has been predicted satisfactorily. Due to the simple phenomenological structure of the model, a user-friendly model application and a short computing time is achieved.

1.
Wimmer
,
A.
,
Chmela
,
F.
,
Engelmayer
,
M.
, and
Winter
,
H.
, 2003, “
Virtuelle Brennverfahrensentwicklung bei Großmotoren
,”
Proceedings of the Ninth Symposium: The Working Process of the Internal Combustion Engine
, Graz.
2.
Chmela
,
F.
,
Dimitrov
,
D.
, and
Wimmer
,
A.
, 2007, “
Simulation der Verbrennung bei Vorkammer-Großgasmotoren
,”
Proceedings of the 11th Symposium: The Working Process of the Internal Combustion Engine
, Graz.
3.
Chmela
,
F.
,
Engelmayer
,
M.
,
Beran
,
R.
, and
Ludu
,
A.
, 2003, “
Prediction of Heat Release Rate and NOx Emission for Large Open Chamber Gas Engines With Spark Ignition
,”
Proceedings of the Third Dessau Gas Engine Conference
, Dessau.
4.
Schnessl
,
E.
,
Kogler
,
G.
,
Strasser
,
Ch.
,
Winter
,
H.
, and
Wimmer
,
A.
, 2003, “
Potential verschiedener Brennverfahren für den Einsatz in Gasmotoren
,”
Proceedings of the Third Dessauer Gasmotoren-Konferenz
, Dessau.
5.
Zhu
,
J.
,
Wimmer
,
A.
,
Schneßl
,
E.
,
Winter
,
H.
, and
Kogler
,
G.
, 2007, “
Development of Combustion Concepts for Large Engines Based on Single Cylinder Research Engines
,”
International Symposium on I.C. Engines
, Shanghai.
6.
Chmela
,
F.
,
Pirker
,
G.
, and
Wimmer
,
A.
, 2008, “
Automatisierte Bestimmung der Eingangsparameter von Verbrennungs-modellen auf der Basis des gemessenen Zylinderdruck-verlaufs
,”
FVV Informationstagung Motoren-Frühjahrstagung 2008
, Paper No. Heft R541.
7.
Wimmer
,
A.
, and
Schnessl
,
E.
, 2006, “
Effects of Humidity and Ambient Temperature on Engine Performance of Lean Burn Natural Gas Engines
,”
ASME Fall Conference
, Sacramento, Paper No. ICEF2006-1559.
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