MBD Simulation on IC Engine Valve Train
AIM
To perform MBD Simulation on IC Engine Valve Train.
INTRODUCTION
A 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.
OBJECTIVE
CALCULATIONS
In our case
D1= 35mm, so R1=17.5mm
D2= 20mm, so R2=10mm
CASE 1: Cam lift is 3.5mm, so distance between centers is 11mm
CASE 2: Cam lift is 6mm, so distance betweeen centers is 13.5mm
For detailed result set the frame rate to 9000 frames per sec and also enable precise contact.
Also change the component to cast carbon steel.
PARTS
VALVE
VALVE STEM
ROCKER ARM
PUSH ROD
CAM
COMPLETE ASSEMBLY
RESULT
CASE 1
for 3.5mm cam lift
VALVE LIFT
Contact forces between cam and push rod
Contact force between push rod and rocker arm
Contact force between rocker arm and valve (magnitude)
Contact force between rocker arm and valve (x component)
CASE 2
for 6mm cam lift
VALVE LIFT
Contact force between cam and push rod
Contact force between push rod and rocker arm
Contact force between rocker arm and valve (magnitude)
Contact force between rocker arm and valve (x component)
CONCLUSION
The valve displacement is higher in case of 6mm than 3.5mm. This cause variation in the flow of fuel air misture through the valve opening.
The contact force between the various contacting components has increased when the cam lift is increased.
The contact force between the Rocker arm and valve varies while measuring with respect to the X direction and measuring with respect to magnitude, this is because in magnitude the net force is calculated in all the direction whereas in x component, the force in x direction is calculated (which is frictional force).