MBD Simulation on IC Engine Valve Train
OBJECTIVE:
To design and model the CAM and piston Valve train assembly and run the motion analysis for the same.
AIM OF THE CHALLENGE:
- Model the parts and assemble them in SolidWorks.
- Run the simulation using the below parameters
| Sl.No | CAM Lift (mm) | Speed (RPM) | Material |
| 1 | 3.5 | 1500 | Cast Carbon Steel |
| 2 | 6 | 1500 |
Cast Carbon Steel |
To Obtain the
- Valve Lift.
- The contact force between
- Cam and Push Rod
- Pushrod and Rocker Arm
- Rocker Arm and Valve
Explain why the contact force between the Rocker arm and valve varies while measuring with respect to the X direction and measuring with respect to magnitude.
THEORY:
The Valve Train consists of the mechanism that opens and closes the valves in engine. The opening and closing system is called a camshaft. ... The cams on the shaft activate the valves directly or through a very short linkage called Rocker Arm. This is responsible for transferring the rotational movement of the camshaft into the opening and closing of the intake and exhaust valves. It consist of various parts like cam, rocker arm , valve, pushrod etc...
PROCEDURE:
Simulation Setup:
Speed - 1500 RPM (clockwise)
Spring is attached btw valve and its mount of stiffness 10 N/mm and free length 45 mm.
CAD MODELS :
CAM :
PUSHROD:
ROCKER ARM :
VALVE :
VALVE STEM:
VALVE TRAIN ASSEMBLY:
OBSERVATIONS AND GRAPHS:
CASE 1:
CAM LIFT = 3.5MM
SPEED = 1500RPM
MATERIAL : CAST CARBON STEEL
CALCULATION:
CAM Lift can be derived from the sketch
● The diameter of lower circle (D1)- 27 mm
● The diameter of upper circle (D2)- 14 mm
● The distance between two centres (L)- 10 mm
CAM Lift = (L-R1)+R2
= (10-13.5)+7
= 3.5 mm
CASE 2:
CAM LIFT = 6 MM
SPEED = 1500RPM
MATERIAL : CAST CARBON STEEL
CAM Lift can be derived from the sketch
● The diameter of lower circle (D1)- 27 mm
● The diameter of upper circle (D2)- 14 mm
● The distance between two centres (L)- 10 mm
CAM Lift = (L-R1)+R2
= (12-10)+4
= 6 mm
EXPLANATION OF THE CURVES:
CASE 1:
VALVE LIFT:
CONTACT FORCE:
A) CAM AND PUSH ROD
B) PUSHROD AND ROCKER ARM
C) ROCKER ARM AND VALVE
CASE 2:
VALVE LIFT:
CONTACT FORCE:
A) CAM AND PUSH ROD
B) PUSHROD AND ROCKER ARM
C) ROCKER ARM AND VALVE
INFERENCE:
The contact force between the Rocker arm and valve varies because the contact force of Rocker arm and valve along x axis is frictional force that cause by the sliding of Rocker arm on the valve but the contact force of Rocker arm and valve along magnitude consider magnitude of both the friction force occuring in x direction and the force in other directions also to move the valve.
CONCLUSION:
CAM and piston Valve train assembly and run the motion analysis for the same was studied and analyzed.