MBD Simulation on IC Engine Valve Train
MBD simulation on IC Engine valve train
Objective:
To create a model of cam and its associated parts for the IC engine valve train to run MBD simulation on that.
Run the simulation using the below parameters.
|
SL.NO |
CAM LIFT(MM) |
SPEED(RPM) |
MATERIALS |
|
1 |
3.5 |
1500 |
Steel dry |
|
2 |
6 |
1500 |
Steel dry |
Obtain the plot of
Valve lift
The contact force between them
Cam and push rod
Push rod and rocker arm
Rocker arm and valve
INTRODUCTION:
A valve train 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
Component used in valve train mechanism:
- Camshaft
- Pushrods
- Rocker arm
- Valve
- Valve mount
Calculation for cam lift:
Simulation setup:
Rotation of cam in clockwise direction
Speed of crank is 1500 rpm
A spring attached between valve and valve mount
Free length of spring is given as 52mm and spring constant of 10n/mm
Material used to calculate contact force between two mating component is steel dry.
Assembly and result:
Case1: Cam lifts of 3.5mm
Assembly of valve train
Fig1 Linear displacement of push rod
Linear displacement of valve
Contact force between cam and push rod
Contact between push rod and rocker arm
Contact force between rocker arm and valve (along magnitude)
Contact force between rocker arm and valve (along x-axis)
Case ii: cam lift for 6 mm
Assembly of valve train
Fig1 Linear displacement of push rod
Linear displacement of valve
Contact force between cam and push rod
Contact between push rod and rocker arm
Contact force between rocker arm and valve (along magnitude)
Contact force between rocker arm and valve (along x-axis)
Conclusions:
For the 1st case as we give cam lift of 3.5mm, the valve displacement is around 1mm but when we increase the cam lift to 6mm we got valve displacement of around 3.1mm from both the cases 1&2 contact force between push rod and cam ,and push rod and rocker arm are approximately same.
When comparing the contact force between case 1&2 the contact force is much more in case 2 then compare to case1 .it’s because the cam lift is ore in case 2 so the force required compress the spring is more.
References:
https://skill-lync.com/projects/MBD-Simulation-on-IC-Engine-Valve-Train-82128
https://en.wikipedia.org/wiki