Design of IC Engine Components

1. DESIGN OF IC ENGINE COMPONENTS
DR.MAHALINGAM COLLEGE OF ENGINEERING AND TECHNOLOGY, POLLACHI.
P.KARUPPUSAMY AP / AUTO
R.VISHNURAMESHKUMAR AP / AUTO
DEPARTMENT OF AUTOMOBILE ENGINEERING
Reference:
1. A text book of MACHINE DESIGN – R.S. KHURMI
2. Design of MACHINE ELEMENTS – V.B. BHANDARI
Year / Sem : III / VI
AY : 2018 – 19

2. UNIT – II
DESIGN OF VALVES
2

3. VALVE OPERATING SYSTEMS
Overhead valve drive Overhead camshaft valve drive

4. VALVE DESIGN
1. Poppet valve
2. Rotary valve
3. Disk valve
TYPES
The most commonly used valve is the poppet valve
a. cheap,
b. good flow properties,
c. good seating,
d. Easy lubrication, and
e. good heat transfer to the cylinder head.

5. POPPET VALVE DESIGN
Different poppet valve designs

6. Inlet valves are usually constructed using the one-piece design,
whereas Exhaust Valves are generally constructed using a two-piece design.
Valve seats formed in-situ within the cast iron cylinder heads were originally used in
passenger car engines.
In order to provide greater wear resistance, hardfacing alloys were developed as well as
seat inserts designed to be press-fitted into the cylinder heads

7. Valve seating face angle
1. The hottest part of the valve, under running conditions, is the underside of the head. The
additional expansion of this side makes the two seating face angles equal at running
temperatures.
2. When the valve is very hot the spring load can cause the head to dish slightly, which can
lift the inner edge of the valve seating face (nearest the combustion chamber) clear of the
seat insert if the angles are the same when cold.
3. The risk of trapping combustion particles between the two seating faces is reduced

8. Material Requirements
 Good heat conduction
 Good heat resistance
 Corrosion resistance
 Wear resistance
 Shock resistance
Materials
 Inlet Valve – Nickel Chromium alloy Steel
 Exhaust Valve – Silichrome steel

9. Design of Engine Valve (Poppet or Mushroom Valve)
 Size of the valve port
 Thickness of the valve disc
 Maximum lift of the valve
 Valve stem diameter

10. a) Size of the valve port
Volume displaced by piston = Volume displaced through the valve

11. b) Thickness of the valve disc

12. c) Maximum lift of the valve

13. d) Valve stem diameter

14. Tutorial
The conical valve of an I. C. engine is 60 mm in diameter and is subjected to a maximum gas
pressure of 4 N/mm2. The safe stress in bending for the valve material is 46 MPa. The valve
is made of steel for which k = 0.42. The angle at which the valve disc seat is tapered is 30°.
Determine :
1. thickness of the valve head;
2. stem diameter;
3. maximum lilt of the valve.