MBD Simulation on a Piston Assembly
AIM - TO STUDY AND ANALYSE THE MOTION OF A PISTON ASSEMBLY USING SOLIDWORKS MOTION.
THEORY A piston assembly is the most important part of an internal combustion engine. It basically consist of following parts:-
A piston, connecting rod, crank, gudgeon pin, crank pin, piston rings, etc.
WORKING
- When the charge is admitted into the combustion chamber, the piston moves upward and compresses the charge, as soon as the charge is ignited by a spark, the fuel burns rapidly thus a large amount of thrust force is generated on the piston head which tends to push the piston downwads thus in this way the reciprocating motion of the piston is converted into rotary motion of the crank
- In both two stroke and four stroke IC engine the crank rotates by 180 degree when the piston reciprocates from TDC to BDC and vice versa.
- In two stroke engine the power is obtained in every 2nd stroke whereas in case of four stroke engine the power is obtained in every 4th stroke.
SETUP -
First of all we will model the parts and then do the assembly of the various components.
PISTON
CONNECTING ROD UPPER END
CONNECTING ROD LOWER END
CRANK
GUDGEON PIN
ASSEMBLY
In the assembly basically we need to create three kind of arrangements, the following three arrangements are explained below.
ARRANGEMENT NO. 1
"0" mm offset
10 mm Positive Offset
10 mm Negative Offset
SIMULATION SETUP
Step 1 Go to SOLIDWORKS motion analysis
Step 2 Choose motion study properties and rnter the FPS as 7200 and choose precise contact
Step 3 Go to contact and apply the solid contacts between the various parts which are in contact to eachother
Step 4 Apply motor to the crank shaft and enter the value of 2000 RPM
Step 5 Run the Study.
OBSERVATIONS
CASE1
0 MM OFFSET
In this case as can be seen from the diagram below, the piston undergoes a simple harmonic motion.
CASE 2
10 MM POSITIVE OFFSET
In this case as well it can be seen that the reciprocation of the piston causes simple harmonic motion within a fixed range.
CASE 3
10 MM NEGITIVE PLOT
The same simple harmonic motion can be observed in this case also.
RESULTS
From the plot obtained in the three cases it can be interpreted that there was no major changes in the displacement of the piston and it was nearly same in all the three cases.
VIDEO OF THE SIMULATION
DOWNLOAD THE CAD FILES FROM HERE
https://drive.google.com/drive/folders/1EYwyDZQ25yQESZPxpSbdw2JgJPQvKJoD?usp=sharing