PROFESSIONAL MOTORSPORT
SIMULATION SOFTWARE
Due to limited amount of air, test for combustion model
With the DTM many parts of the engine where described. However the main limitation for the engine power was generated by the air restrictor.
All the air entering the engine had to pass this restrictor. Nature limits the amount of air which can flow through such an air restrictor. This provides another very interesting opportunity to test and validate the accuracy of the engine model.
Bore x Stroke:
Compression ratio:
Mechanical Losses:
92 x 75.2 [mm] (8 Cylinder)
14.5 : 1
0.8 [Bar]
Intake Valves:
Exhaust Valves:
2 x 37 [mm]
2 x 33 [mm]
Inlet Camshaft :
Exhaust Camshaft :
238 [mm] (@ 1 [mm] lift)
230 [mm] (@ 1 [mm] lift)
Intake runner:
Primary exhaust:
350 x 48 [mm]
700 x 44 [mm]
In reality they delivered between 475 - 485 [Hp]
![Simulated power curve of a DTM engine with 2 x 28 [mm] air restrictors](assets/img/menus/dtm_engine.png)
Optimizing valve timing, intake and exhaust parameters leads to the power curve as seen above.
Although official figures are not available, the shown power curve is close enough to use in the lap simulation to get a accurate correlation with the real car data.
Leading to a low fill rate of the cylinder
In the figure showing the fill rate of the cylinder, it can clearly been seen when the air restrictors limit the amount of air flow.
The transition when the restrictor cuts in, is in reality less sharp than the model presents it here. It is a detail which we will try to improve in the future.
At the maximum torque point
Due to the high compression ratio of 14.5:1, the ignition cannot be run at the 'optimal' advance as can be seen in the figure.
The figure shows the influence of ignition advance on the delivered torque of the engine at 5300 [rpm].