Modeling Flywheel-Speed Variations Based on Cylinder Pressure
Combustion supervision by evaluating flywheel speed variations is a
common approach in the automotive industry. This often involves
preliminary measurements. An adequate model for simulating flywheel
speed can assist to avoid some of these preliminary measurements.
A physical nonlinear model for simulating flywheel speed based on
cylinder pressure information is investigated in this work.
Measurements were conducted at Scania in a test bed and on a chassis
dynamometer. The model was implemented in MATLAB/Simulink and
simulations are compared to measured data. The first model can not
explain all dynamics for the measurements in the test bed so extended
models are examined. A model using a dynamically equivalent model of
the crank-slider mechanism shows no difference from the simple model,
whereas a model including a driveline can explain more from the
test-bed measurements. When simulating the setups used at the chassis
dynamometer, the simplest model works best. Yet, it is not very
accurate and it is proposed that optimization of parameter values
might improve the model further. A sensitivity analysis shows that
the model is fairly robust to parameter changes.
A continuation of this work might include optimization to estimate
parameter values in the model. Investigating methods for combustion
supervision may also be a future issue.
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Last updated: 2013-12-03