The engine studied is a new one : 3.2L, V6, GDI with double
VVT (intake and exhaust).
The engine has been studied in the maximum power
configuration and the performances have been studied at
different engine speed, from 1000 to 7000 [rpm] with step of
500 [rpm].
For the performance predication a commercial 1D fluid-dynamic
solver (Gtpower) has been coupled with the optimisation
algorithm.
The VVA system is not yet present on the engine. For this
reason, the optimisation technique has been used in the project
phase as mean to evaluate engine performance variation.
The aim of the work is the optimisation of engine torque
using Variable Valve Actuation Systems: VVT for intake
and exhaust timing and VVA for the intake valve lift and
opening duration .
The variable valve actuation systems used for the optimisation
work are:
- VVT ( Variable Valve Timing): this system is able to change the
position of valve start opening (see1)
- VVA (Variable Valve Actuation): this system is able to change valve
lift and opening duration
NOTE:The combined use of these two systems allows the users to obtain the required
valve lift characteristics for typical performance objectives.
Before the optimisation phase the model has been tuned
using some experimental data, such as:
1) Pressure waves on the intake and exhaust manifold
2) In cylinder pressure
3) Combustion rate
4) Friction
5) Pressure losses on the intake and exhaust systems
6) Temperature on the catalyst cupel (intake and exhaust)
NOTE: The VVA system is able to create different valve lift and opening
duration. Using modeFrontier, it is possible to consider the valve lift and
opening duration plots as numbers, and so as parameters. Following that way,
calling the files relative to them with numbers (increasing at increasing lift)
the optimisation solver is able to evaluate their influence in a correct
way.
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