Gas exchange tuning in a single-cylinder research engine model
Typ
Examensarbete för masterexamen
Program
Automotive engineering (MPAUT), MSc
Publicerad
2021
Författare
Edholm, Oskar
Tagesson, Filip
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The development of new engines is a complex, multi-year endeavor and the process is
lined with numerous steps of testing and verification. One of these steps is the use of
single-cylinder research engines, which are used to limit variables and enable fast changes
of components, methods and strategies when in the early stages of engine development.
When the single-cylinder testing is done, the concepts from the single-cylinder are applied
in the multi-cylinder engine, this introduces errors, as the pressure dynamics in the intake
and exhaust are different in the two engine types due to the number of cylinders and
manifold structures. To lessen the impact of this disparity the pressure dynamics in the
single-cylinder engine should operate more like the multi-cylinder engine it is trying to
replicate.
In this report a GT-Suite model of a single-cylinder engine is created, optimized and ver ified to closely replicate an existing research engine. The pressure pulses in the intake
and exhaust manifold are measured and compared to the ones of a multi-cylinder engine
that the single-cylinder is replicating. Thereafter, concepts to modify the pressure pulses
are introduced, modelled and tested. The concepts are optimized to modify the pressure
pulses in a way that makes them match the multi-cylinder pulses as close as possible.
Lastly the effect of altering the cylinder volume of the single-cylinder engine model is
assessed.
All proposed designs showed improvement towards replicating the multi-cylinder pressure
dynamics and both intake and exhaust utilize the same concept topologically but vastly
different in dimensions. This is not unexpected as the pressures on the intake and exhaust
behave very differently. This result was verified for multiple engine operating conditions
and showed beneficial in all cases.
If the cylinder volume of the engine is altered but all else in kept identical only very minor
changes in pressures are observed when compared to the original cylinder volume engine.
This is also true when applying the suggested topology modification.
Beskrivning
Ämne/nyckelord
Gas exchange, Engine modelling, Optimization, GT-Power, Simulation, Single-cylinder research engine, Multi-cylinder engine