MBD Simulation on IC Engine Valve Train
Objective:-
In this project, we will model an IC engine valve train which consists of essential parts as a cam, push rod, rocker arm, valve mount, and valve, make a assembly in SolidWorks and run the motion analysis to find the contact force encountered between the parts and show the reason for 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.
Introduction:-
IC Engines uses valves to handle charge in and out of the cylinder for their operation there are intake valves and exhaust valves which are to spring less be operate at right time when needed and remains close to seal the cylinder when compression and combustion is occurred. To do this opening and closing of valves cam and follower mechanism is used.The whole assembly is called IC engine valve train.
There are five parts in this mechanism:
- Cam
- Rocker arm
- Push rod
- Valve
- Valve mount
Designing 3D models:
Cam:- Cams are used to convert rotary to linear (reciprocating) motion. As the cam rotates, the follower rises and falls in a process known as reciprocating motion.
Pushrod:-To provide the lift.
Rocker arm:- It is an oscillating lever that conveys radial movement from the cam lobe into linear movement at the poppet valve to open it.
Valve:- Valve is used as a barrier to restrict the flow of intake and exhaust gases.
Valve Mount:-This acts as the stoppage for the valve and limits the movement of the valve.
Assembly:- Assembly is created by applying appropriate constraints.
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.
- Next, give the rotation to the cam with 1500 RPM.
- Set up a linear spring between a valve and the valve mount with the spring stiffness of 10 N/mm and free length 45 mm.
- Change the frames to 7200 frames per sec and use precise contact.
- Select the entire assembly and assign the material as follows, go to Material-Edit material and select Cast Carbon Steel and click apply.
- Now click the calculation button.
- Run the analysis for the required time.
There are two cases to follow to get the desired motion analysis and the plots. They are as follows
| Sl.No | CAM Lift (mm) | Speed (RPM) | Material |
| 1 | 3.5 | 1500 | Cast Carbon Steel |
| 2 | 6 | 1500 |
Cast Carbon Steel |
We have to calculate center distance as followed:
Case 1 (Cam lift=3.5mm) :-
Given R1=17.5mm
R2=10mm
CAM Lift = (L-R1)+R2
L=CAM Lift +R1 -R2
=3.5+17.5-10
=11mm
Case 2 (Cam lift=6mm) :-
Given R1=17.5mm
R2=10mm
CAM Lift = (L-R1)+R2
L=CAM Lift +R1 -R2
=6+17.5-10
=13.5mm
Results and explanation:-
Case 1 (Cam lift=3.5mm) :-
Contact Force Cam and Push rod :-
Contact Force Push rod and Rocker arm:-
Contact Force Rocker arm and valve (X- direction):-
Contact Force Rocker arm and valve (Magnitude):-
Case 2 (Cam lift=6mm) :-
Contact Force Cam and Push rod :-
Contact Force Push rod and Rocker arm:-
Contact Force Rocker arm and valve (X- direction):-
Contact Force Rocker arm and valve (Magnitude):-
Animation:-
Observation and Results:-
There is more smooth movement in case of 6mm cam lift than 3.5mm cam lift.