Development of dynamic controller for static piston ring test rig
Lautamäki, Riku (2025)
2025
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-202505059147
https://urn.fi/URN:NBN:fi:amk-202505059147
Tiivistelmä
This thesis was done for Wärtsilä Finland Oy- Engine Structure & Power Systems department. The aim of the thesis was to develop a dynamic version from the static piston ring rig. The thesis was executed by designing and manufacturing a pressure controller for the current test rig. The aim was to make it simple but flexible as possible for ease of use. The purpose of this thesis was to correct the existing problems and offer more reliable data.
The current static test rig is used to obtain data from various piston rings, to clarify the ring characteristics effects on blowby and comparison of data to actual measured values. During the tests it was noticed that the results varied, and the repeatability accuracy wasn’t the greatest. During a manual pressure cycle on the same ring, the blowby changed which indicates that the piston ring is moving and trying to seat properly. Some multiring tests showed that during pressurising, the pressure builds up between the piston rings which results in the upper ring lifting. The lifting of the piston ring causes increase in blowby, giving faulty results.
The solution could be adjustable pressure cycles. With the help of pulsing action, the piston ring might stay seated better during the tests. As a result, the data relevancy and accuracy would be im-proved. During the work two prototypes were made, where the other one was selected for further processing. The tests made with the final version showed that the sealing of the piston rings takes place quite randomly, but usually as a result of sudden pressurising through a large orifice. When the rings start to seal the system works as intend-ed, and the average flow can be extracted from the measured blowby. Based on the tests, it can be stated that the controlling and the measuring devices should be optimized to achieve the best results.
The current static test rig is used to obtain data from various piston rings, to clarify the ring characteristics effects on blowby and comparison of data to actual measured values. During the tests it was noticed that the results varied, and the repeatability accuracy wasn’t the greatest. During a manual pressure cycle on the same ring, the blowby changed which indicates that the piston ring is moving and trying to seat properly. Some multiring tests showed that during pressurising, the pressure builds up between the piston rings which results in the upper ring lifting. The lifting of the piston ring causes increase in blowby, giving faulty results.
The solution could be adjustable pressure cycles. With the help of pulsing action, the piston ring might stay seated better during the tests. As a result, the data relevancy and accuracy would be im-proved. During the work two prototypes were made, where the other one was selected for further processing. The tests made with the final version showed that the sealing of the piston rings takes place quite randomly, but usually as a result of sudden pressurising through a large orifice. When the rings start to seal the system works as intend-ed, and the average flow can be extracted from the measured blowby. Based on the tests, it can be stated that the controlling and the measuring devices should be optimized to achieve the best results.