MBD Simulation on IC Engine Valve Train
Objective:
- To model the parts and assemble the IC Engine Valve train.
- To run the MBD 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 observe and plot for the following results
- Valve Lift.
- The contact force between
- Cam and Push Rod
- Pushrod and Rocker Arm
- Rocker Arm and Valve
IC Engine Valve Train
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 combustion chamber once combustion is completed.
Cam Lift
This is the distance the cam lobe rises away from the base circle of the camshaft. It is the distance the lifter will move. It is also called "lobe lift." Some camshaft manufacturers list this value.
3D Modeeling, Assembly and MBD Simulation Setup:
The IC Engine Valve Train Mechanism involves
1. Cam,
2.Push rod,
3.Rocker arm
4.Valve
5.Valve stem
Images of the 3D modelled components
1. Cam
2.Push rod
3.Rocker arm
4.Valve
5.Valve stem
Assembly of the IC Engine Valve Train Mechanism.
MBD Simulation Setup for the two different cam lift conditions.
For the Motion Analysis study, the following conditions to be applied
* Rotating motor is applied to the Cam with 1500 rpm and direction of rotation.
* All contacts are defined between the components of IC Engine Valve Train Mechanism
* Simulation is then run, and results of Valve Linear displacement, Contact forces in both the cases are exported to Excel and plotted.
Results and plots:
case1: for 3.5 mm can lift
The cam lift is related with the formula
CAM Lift = (L-R1)+R2, and the model is reflected as same to attain 3.5mm cam lift
Linear displacement of the push rod w.r.t to time
Contact force between the Cam and the push rod w.r.t time
Contact force between the arm and the push rod w.r.t time
Contact force between the arm and the valve rod w.r.t time
Contact force in X-Direction between the arm and the push rod w.r.t time
case2: for 6 mm can lift
The cam lift is related with the formula
CAM Lift = (L-R1)+R2, and the model is reflected as same to attain 6mm cam lift
Linear displacement of the push rod w.r.t to time
Contact force between the Cam and the push rod w.r.t time
Contact force between the arm and the push rod w.r.t time
Contact force between the arm and the push rod w.r.t time
Contact force in X-Direction between the arm and the push rod w.r.t time
Observations:
- The valve lift depends on the cam lift and the legnth of the rocker arm. While we change the cam lift valve in our cases, the valve lift also increases proportionally.
- The contact forces between all the components follows similar pattern and the forces are maximum at the highest cam lift.
- The X direction of contact force between the rocker arm and the valve represnts the friction force for the sliding motion between them and the +ve and -ve valve corresponds to the extension and contraction of the valve.
CAD Models link:
https://drive.google.com/drive/folders/1IUzxM6qYp-bhO17JN4sk-dvS3-Z14jVD?usp=sharing