MBD Simulation on IC Engine Valve Train
Aim:
To Model the parts and assemble them in SolidWorks and Run the simulation using the below parameters.
Solution:
About engine valve train: (reference:wikipedia)
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 combusion chamber once combustion is completed.
All the parts are designed in solidworks and assembled in the same software also done a motion study on it based on the given prerequesties and they are explained below.
Part Design:
Part1: Cam
There are two different cam profile is used in this MBD and they are designed based on the following procedure.
First I selected the front plan(note : here all the parts are builded in the front plan), then created two circles one is with higher diameter and other is with lower diameter and the smaller one is coincident at the diameter line of the bigger circle and then create two tangent line with these circles and then trim unwanted lines using power trim option and then make whole sketch dimensionally constrained and exit sketch, then select extruded bose and select the sketch and give the thickness based on the lecture video and the save this as cam.
Coming to the cam lift we have to set the center distance of the two circles as for the first cam as 12.5mm and for the second one it is 11mm, and the diameter of the bigger circle is 25mm and the other one is 12mm, and for other cam it is 25mm and 10mm respectively.
Then the cam lift is calculated based on the formula as follow;
CAM-Lift = (L-R1)+R2;
CAM-Lift = (11-12.5)+5
CAM-Lift = 3.5mm by this i found the value of length and diameters
CAM-Lift = (12.5-12.5)+6
CAM-Lift = 6mm by this i found the value of length and diameters for the second CAM.
Part2: Push Rod.
First I have selected the front plane and then start sketching using line command draw some horizontal and vertical lines and make them dimensionally constrained and then make the sketch closed and then exit the sketch and select the revolve bose and this will make a rod and make one corner in the rounded condition.Then save it as Push rod.
Part3: Rocker Arm.
First I have selected the front plan and then start sketch using three point arc and make three circles and make them joined at their ends and make them dimensionally constrained and join those lines with line command and made them dimensionally constrained and then save them as Rocker arm.
Part4: Valve cap and Valve
First I have selected the front plan and then start sketch by using line create a symetric diagram and then make it dimensionally constrained and by using a three point arc complete the bottom and make it revolve bose command for that completed sketch and save it Valve.
Second I have started a new sketch in front plane and started sketch using line command and draw some horizontal and vertical lines and make them dimensionally constrained and after this revolve it as done in the valve part and save it as valve cap.
Assembly:
Take all the part to the assembly page and the first imported part should be checked to set at float condition and then constrained it based on the lecture vidoe, in this assembly i used move component command and make physical movement this will easy to make the components constrained i.e., physically constrained and save it as engine valve train.
Then select all the Components and add material from the material liberary as Cast Carbon steel and again save.
Motion Study (Multi Body Dynamics): for cam lift 3.5mm
Motor: Giving the motor force to the cam profile and this will make the CAM profile to rotate.
Contact Force: Step1: Giving contact force to the cam and the push rod and uncheck the material option.
Step2: Giving contact force to the push rod and Rocker arm and make the same for material option as given in previous condition.
Step3: Giving contact force to the Rocker arm and Valve and make the same for material option as given in previous condition.
Step4: Make cap fixed at the assembled position.
Spring contact: Then select the edge of the max diameter of the valve and the edge of the valve cap and give a spring stiffnes of about 10N/m^2 and compression as 45mm.
After completing this started Calculation using calculate button; and after this the video made during calculation is captured using camtasia and uploaded in youtube and the link is shared below and i made a plot for the following contact force's of the component,
Cam and Push Rod
Pushrod and Rocker Arm
Rocker Arm and Valve
plot on Cam and Push Rod
Plot on Pushrod and Rocker Arm
Plot on Rocker Arm and Valve
Motion Study (Multi Body Dynamics): for cam lift 6mm
Motor: Giving the motor force to the cam profile and this will make the CAM profile to rotate.
Contact Force: Step1: Giving contact force to the cam and the push rod and uncheck the material option.
Step2: Giving contact force to the push rod and Rocker arm and make the same for material option as given in previous condition.
Step3: Giving contact force to the Rocker arm and Valve and make the same for material option as given in previous condition.
Step4: Make cap fixed at the assembled position.
Spring contact: Then select the edge of the max diameter of the valve and the edge of the valve cap and give a spring stiffnes of about 10N/m^2 and compression as 45mm.
After completing this started Calculation using calculate button; and after this the video made during calculation is captured using camtasia and uploaded in youtube and the link is shared below and i made a plot for the following contact force's of the component,
Cam and Push Rod
Pushrod and Rocker Arm
Rocker Arm and Valve
plot on Cam and Push Rod
Plot Pushrod and Rocker Arm
Plot on Rocker Arm and Valve
Parts are uploaded in drive and the link is shared :
https://drive.google.com/drive/folders/1t9ny6jhs1wBWkgQ4ZcWe3G2Uts8mjdeh?usp=sharing
Youtube Video Links:
Engine valve train with CAM lift 3.5mm: https://youtu.be/6V9Two946F8
Engine valve train with CAM lift 6mm: https://youtu.be/xZoIllfwwWU
Result:
Finally i have made a motion study and made three contact force graph on the components and their results are shown above