1. Turbo-charging of I.C. Engines
P M V Subbarao
Professor
Mechanical Engineering Department
Going for Artificially Breathing Engines….

2. Turbocharger

3. Matching of Turbocharger with Engine
I.C. Engines are semi-control volumes.
Can accept or deliver flow across the boundary intermittently.
Turbocharger is a combination of two pure control volumes.
They need to continuously accept and deliver flow across boundary.
Demands a special engineering art called as tuning.
An art of tuning CVs with CM.
Fluid Dynamic Turning.
Thermodynamic Tuning.

4. The Problem of Fluid Dynamic TuningТ C 1 2 3 4
P1, T1
P2, T2
P3, T3
P4, T4
Engine

5. Turbocharged engine with Reservoirs

6. Thermodynamic Tuning Т C 1 2 3 4
P1, T1
P2, T2
P3, T3
P4, T4
Engine

7. Compressor Sizing
A compressor is sized based on two pieces of information, boost pressure and airflow.
The desired boost pressure is chosen based on the performance objectives.
The minimum boost pressure needed to achieve the performance objectives is to be evaluated.
The airflow is directly related to the engine speed and is thus calculated based on what part of the speed range is desired to experience a power increase.
Once the boost pressure and airflow are known, they are used to size the compressor.
A compressor works best at a particular combination of airflow and boost pressure.

8. The First Law of Tuning
A comparison of this optimal combination of boost pressure and airflow for a given compressor to the Engine anticipated combination of boost pressure and airflow determines the suitability of the compressor for the system.

9. Thermo-fluid Dynamics of Compressor
Radial Flow Compressor
Mixed Flow Compressor

10. Geometry of Turbo-compressor Wheel

11. Thermodynamic View of a Real isentropic Compressor
Only Impeller can consume Power !!!
p02=p02i p2
Only Impeller can consume Power !!!
T02=T02i
p2i T
p01 p1
T01 s