MBD simulation on IC engine valve train
Aim:
To model the various components in IC engine valve train and assembled it. To analyse the various parameters in the IC engine valve train using solidworks.
Objectives:
- The various parts in the IC engine valve train such as a) CAM, b) Push rod, c) Rocker arm, d) Valve and e) Valve mount is modelled.
- The CAM is modelled with the different CAM lifts of 3.5mm and 6mm.
- The CAM lift can be calculated by the following formulae.
- The modelled parts are assembled to done the MBD simulation.
- The MBD analysis was done with different paramters.
| Sl.No | CAM Lift (mm) | Speed (RPM) | Material |
| 1 | 3.5 | 1500 | Cast Carbon Steel |
| 2 | 6 | 1500 |
Cast Carbon Steel |
- The valve lift should be obtained.
- The contact force between CAM and push rod should be obtained.
- The contact force between push rod and the rocker arm should be obtained.
- The contact fore between rocker arm and valve should be measured both on magnitude and on X direction separately.
- The results should be discussed.
Valve:
The valves play an important role in the engine assembly. It allows the fuel to enter inside the cylinder. It also lets the exhaust fuel to go out. The valves should be opened in a particular time based on the process occurred in the combustion chamber.
Valve train assembly:
The valve train assembly helps the valves to open and close in the correct time. Based on the valve lift needed, the CAM should be designed. The CAM is attached with push rod. The push rod is connected with rocker arm and the rocker arm is connected with valve. The valve has a valve mount. The spring is attached in between the valve mount and the upper part of the valve. Based on the CAM rotation, the valves are opened and closed.
Part modelling:
The various parts in the IC engine valve train are modelled in solidworks with defined input parameters.
1) CAM:
2) Push rod:
3) Rocker arm:
4) Valve:
5) Valve mount:
The material for all the parts are defined as cast carbon steel.
All the parts are assembled with proper constraints and then the MDB analysis is started.
Assembly:
MBD analysis:
The MBD analysis is initiated with providing the motor with the speed of 1500 rpm in the CAM. A spring is provided in between the valve mount and the top of the valve. The spring is pretensioned by providing more distance. The spring constant valve of 20 N/mm is initialised.
Case 1:
In case 1, the CAM is designed with the CAM lift of 3.5mm.
a) valve lift:
The valve lift has rised to the maximum of nearly 54mm with the CAM lift of 3.5mm. The valve lift indicates the linear displacement of the valve.
b) Contact force between CAM and push rod:
c) Contact force between push rod and rocker arm:
d) Contact force between rocker arm and valve (magnitude):
e) Contact force between rocker arm and valve (X-direction):
Case 2:
In case 2, the CAM is designed with the CAM lift of 6 mm.
a) valve lift:
The valve lift has rised to the maximum of nearly 56 mm with the CAM lift of 6 mm. The valve lift indicates the linear displacement of the valve.
b) Contact force between CAM and push rod:
c) Contact force between push rod and rocker arm:
d) Contact force between rocker arm and valve (magnitude):
e) Contact force between rocker arm and valve (X-direction):
Results and discusssion:
The contact force plot between rocker arm and valve in X-direction is in the negative side. This is because of the friction force between rocker arm and valve in the X-direction. The valve lift indicate the distance travelled by the valve. The contact forces reaches its peak whenever the maximum extend of the CAM strikes the push rod.
Animation video:
Case 1:
Case 2:
CAD model:
https://drive.google.com/file/d/1FcJm5yrV_-nqbf6QwvBFkun6fNk2xam_/view
Conclusion:
Thus the IC engine valve train assembly was made in solid works and the MBD simulations were done.