1. P M V Subbarao Professor Mechanical Engineering Department
Influence of (Valve) Design & Operational Parameters on Volumetric Efficiency of Engine
P M V Subbarao
Professor
Mechanical Engineering Department
Clues to Improve Filling & Emptying Effectiveness….

2. Frictional Compressible Flow Through Inlet Valve
The real gas flow effects are included by means of an experimentally determined discharge coefficient CD.
When the flow is chocked:

3. Discharge Coefficient:
The value of CD and the available minimum flow area Amin are linked together.
The product CD . Amin is the effective flow area of the valve assembly, AE.

4. Non-dimensional available flow area for real Flow through INLET VALVESc

5. EXHAUST VALVES

6. Selection of Valve Timing for Better Flow

7. Selection of Maximum Valve Lift

8. Selection of Maximum Lift & Valve timings

9. Thermodynamic Parameters Vs Volumetric Efficiency
The volumetric efficiency is a function of
Intake mixture pressure pi.
Intake mixture Temperature Ti.
Fuel/ air ratio (F/A).
Compression ratio r.
Exhaust pressure, pe.
Where m is the mass of mixture in the cylinder at the end of intake stroke.

10. Effect of Fuel composition, Phase & Fuel/air Ratio
In a SI engine, the presence of gaseous fuel and moisture in the intake system reduces the air partial pressure below the mixture pressure.
For a mixture:

11. Fuel Chemistry Vs Volumetric Efficiency
1.0
C8H18
Pa,I/pi
CH4 H2
0.6
1.5
Equivalence Ratio

12. Compression Ratio Vs Volumetric Efficiency

13. Manifold Pressures @1400 rpm : Wide Open Throttle

14. Manifold Pressures @2400 rpm : Wide Open Throttle

15. Manifold Pressures @2000 rpm : 15% Open Throttle

16. Integrated Description of Wave Action