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Flow through Valves

Flow through Valves. P M V Subbarao Professor Mechanical Engineering Department. Breathing abilities are limited by Smallest Areas of Flow …. Another Crucial Hardware in Intake System. A I R. FUEL. A I R. First Law Analysis: USUF. SI Engine. CI Engine.

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Flow through Valves

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  1. Flow through Valves P M V Subbarao Professor Mechanical Engineering Department Breathing abilities are limited by Smallest Areas of Flow ….

  2. Another Crucial Hardware in Intake System

  3. A I R FUEL A I R First Law Analysis: USUF SI Engine CI Engine Intake Process:

  4. SI Engine CI Engine

  5. Ideal Gas Equation for Intake Process Instantaneous EoS: Instantaneous Mass Flow Rate:

  6. Options for Most Important Hardware for Better Breathing Valve/Port Design 1. Poppet Valve 2. Rotary Valve 3. Reed Valve 4. Piston Controlled Porting Valve Location 1. The T-head 2. The L-head 3. The F-head 4. The I-head: (i) Over head Valve (OHV) (ii) Over head Cam (OHC)

  7. Poppet Valve

  8. Rotary Valve

  9. Reed Valve

  10. Arrangement of Poppet Valves • The majority of internal combustion engines also are  classified  according  to  the  arrangement of the intake and exhaust valves, whether the valves are located in the cylinder head or cylinder block. • L-HEAD  —The   intake   and   the exhaust valves are both located on the same side of the piston and cylinder. • The valve operating mechanism is located directly below the valves, and one camshaft actuates both the intake and the exhaust valves

  11. I-HEAD —The   intake   and   the exhaust valves are both mounted in a cylinder head  directly  above  the  cylinder.   • This arrangement requires a tappet, a pushrod, and a rocker arm above the cylinder to reverse the direction of valve movement. • Although this configuration is the most popular for current gasoline and diesel engines. • It was rapidly superseded by the overhead camshaft.

  12. F-HEAD: • The  intake  valves  are normally located in the head, while the exhaust valves are located in the engine block. • The intake valves in the head are actuated from the camshaft through tappets, pushrods, and rocker arms. • The exhaust valves are actuated directly by tappets on the camshaft.

  13. T-HEAD  —The  intake  and  the exhaust valves are located on opposite sides of the cylinder in the engine block, each requires their own camshaft.

  14. SINGLE OVERHEAD CAMSHAFT • The  camshaft  is  located  in  the cylinder  head.   • The  intake  and  the  exhaust  valves are  both  operated  from  a  common  camshaft.   • The valve train may be arranged to operate directly through the lifters, as shown in view A, or by rocker  arms,  as  shown  in  view  B.   • This configuration  is  becoming  popular  for  passenger car gasoline engines.

  15. DOUBLE OVERHEAD CAMSHAFT • When   the   double   overhead camshaft is used, the intake and the exhaust valves each operate from separate camshafts directly through the lifters. • It provides excellent engine  performance  and  is  used  in  more expensive automotive applications.

  16. Typical Intake Poppet Valve Geometry

  17. Typical Exhaust Poppet Valve Geometry

  18. Geometrical Nomenclature for Valves • The instantaneous valve flow area depends on valve lift and the geometrical details of the valve head, seat and stem. • There are three separate stages to the flow area development as valve lift increases.

  19. Stages of Valve Lifting

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