MBD Simulation on IC Engine Valve Train
AIM:-
- To Model the parts
- To Assemble the parts created
- To run simulation on IC Engine Valve under the given conditions
INTRODUCTION:-
A valvetrain or valve train is a mechanical system that controls operation of the intake and exhaust valves in an internal combustion engine. The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) into the combustion chamber, while the exhaust valves control the flow of spent exhaust gasses out of the combusion chamber once combustion is completed.
The valvetrain layout is largely dependent on the location of the camshaft(s). The common valvetrain configurations for piston engines are:
- cam-in-block
- The camshaft is located within the engine block, as either an overhead valve (OHV) or flathead engine. Because they often use pushrods, OHV engines are often called "pushrod engines".
- Overhead Camshaft
- The camshaft(s) are located near the top of the engine, above the combustion chamber.
- Camless
- This layout uses no camshafts at all. Technologies such as solenoids are used to individually actuate the valves.
MODELS:
Cam
When cam lift is 3.5 mm
When cam lift is 6mm
Push Rod
Rocker Arm
Valve
Valve Mount
PROCEDURE:-
- Create 3D model for IC Engine Valve Train
- Create two separate cam's with 3.5 mm lift and 6mm lift.
- Assembling the 3D model by Using the appropriate mates and using move component tool.
- Then follow the process for Motion Analysis
MOTION ANALYSIS:-
To run the Motion Analysis
- First go to motion study and establish contact between Cam and Push rod, Push rod and Rocker Arm, Rocker Arm and Valve.
- Provide rotary motion of 1500 rpm to the cam
- Set up a linear spring between the valve and valve mount
- Change the fps to 7200 fps and use precise contact.
- In order to assign a material to the assembly ,select the whole assembly and assign the material
- Go to Material--> Edit Material--> Select Cast Carbon Steel -->Apply
| Sl.No | CAM Lift (mm) | Speed (RPM) | Material |
| 1 | 3.5 | 1500 | Cast Carbon Steel |
| 2 | 6 | 1500 |
Cast Carbon Steel |
OUTPUT:-
Case 1 : When cam lift is 3.5mm
Linear Displacement of the Valve(valve lift)
Contact force between cam and Pushrod
Contact Force between Push rod and Rocker Arm
Case 2 : When cam lift is 6mm
Linear Displacement of Valve
Contact Force Between Cam and push Rod
Contact Force Between push rod and Rocker arm
Contact Force Between Rocker arm and valve
Youtube link of Animation:
Case:1
Case:2
Google Drive Link
https://drive.google.com/file/d/1Z8Lev3g3xH0WiSLJfQpgiRh1lSaYgKMq/view?usp=sharing
Observation and Results:
- The magnitude if the contact force between the rocker arm and the valve pushes the valve downwards, but its X-component gives us only the friction force of the rocker arm sliding over the face of the valve head.
- The linear Displacement of the valve is greater than the lift produced by the cam as the moment arm towards the valve greater than that towards the push rod.
- The spring is kept constricted from the beginning so that it can work properly.The forces produced by the rotation of the CAM easily compresses the spring and the rocker arm moves beyond it and there won't be any motion transfer to the valve thereafter
- In the plot of contact force against time for rocking arm and the valve, a minimum force is always present due to initial compression state of the spring.