Tekniikan ja innovaatiojohtamisen yksikkö, 2018
Martin Axelsson/Seppo Niemi
Sähkö- ja energiatekniikan koulutusohjelma (DI)
With a homogeneous charge compression ignition (HCCI) combustion it is possible to achieve high thermal efficiency and reduced nitrogen oxide (NOX) and particulate matter (PM) emissions. The challenge in HCCI testing is that the compression end conditions before the ignition are not easily measurable.
The objective of this Master´s thesis work was to develop a method for determining the compression end conditions (pressure, temperature, lambda and exhaust gas recirculation rate) of a dual-fuel engine. The engine under investigation is a two-stage turbocharged medium-high speed engine that uses gas as the main fuel and diesel as the pilot fuel. The engine operates with a homogeneous charge compression ignition (HCCI) combustion process. The knowledge of compression end conditions is needed for better understanding of engine operating conditions and to help the post-processing of test results.
The chosen approach for defining those conditions was to build a response model that can estimate those parameters on the basis of engines operating conditions. It was chosen to use the GT-Power 1D-simulation tool for reproducing totally 63 engine test run cases through the whole engine operative area. The simulated compression end conditions were then combined with empirical data to be used as a base data set for the response model. The response model function uses only measurable parameters to estimate the compression end conditions.
As a result of the thesis work, 1D-simulations for reproducing engine test runs were carried out, and the data from those were used to build a response model. A response model for defining compression end conditions was made. The model was tested with four validation cases that were not included in the simulations during the model building phase. Validation cases proved that developed reproducing method can be used for analysing and post-processing test results.
dual-fuel engine, HCCI, parameters, simulation, GT-Power