Introduction:

Piston assembly consists of a piston, piston rings, and gudgeon pin. It transmits to the connecting rod and crankshaft the gas force produced during combustion. As the piston is attached by means of a gudgeon pin to the small end of the connecting rod. As gas force is transmitted it guides the connecting pin. The mixture of air/fuel is compressed with a piston.

Linear displacement of piston head: The movement of piston head from Top Dead Centre (TDC) is the topmost position of the piston inside the cylinder to Bottom Dead Centre (BDC) is the bottommost position of the piston inside a cylinder.(continuous process)

PROCEDURE FOR DOING Piston Assembly and MOTION STUDY IN SOLID WORKS

Step 1: Creating the cad model for each component in the assembly.

Step 2: Create new assembly select the parts.

CONSTRAINTS: FP-Front Plane; TP-Top plane; RP-Right Plane;

1. Coincide1-crank axis and FP
2. Coincide2-crank axis and TP
3. Distance mate 1-crank FP and assembly FP
4. Coincide3-axis of connecting rod and end cap
5. Coincide4-Connecting rod and end cap face mate
6. Coincide5-Axis of connecting rod and crank
7. Distance mate 2 - faces connecting rod and crank
8. Coincide6-Axis of wrist pin and piston
9. Coincide7-FP of wrist pin and piston
10. Coincide8-Axis of wrist pin and connecting rod
11. Coincide9-FP of connecting rod and piston
12. (Based on casesit differes) Coincide10-RP of assembly and piston(or) Distance mate-RP of assembly and piston

Now the assembly is ready

Step 3: click on assembly at the tools and select rotate component (In move component session).

Step 4: Click the SOLIDWORKS add-in and enable motion study.

Step 5: Now create the new motion study and change animation to motion analysis.

Step 6: Select the motor option to give the torque to the driving wheel (we can give the rpm, time).

Step 7: Select the contact option to give the materials (we can assign material here).

Step 8: Now we give gravity and select y axis.

Step 9: For getting precise click on settings and we can enable precise contact and no of frames.

Step 10: Now we can use calculate options to calculate the results.

Step 11: Now we can plot the graph using plot option.

Step 12: To save in excel (Right click the plot and click the save as CSV option).

Step 13: We can save the results.

Case 1: 0 mm Offset

Case 2: 10 mm Positive Offset - If the crank rotation is in the Clockwise direction.

Case 3: 10 mm Negative Offset - If the crank rotation is in the Clockwise direction.

Superimposing of three cases:

Result video: https://youtu.be/l4SMcilngBo

Conclusion:

From the plot we can conclude that in case three the displacement is faster than other two because of the gravity along downward y-axis. which implies that when rotation along clockwise which makes the crank to rotate speed(because the wrist pin in offseted at rightside in the direction of the rotation of crank).