MBD Simulation on a Piston Assembly

Aim/Objective: MBD Simulation on Piston Assembly.

Theory:

Piston:

A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder.

Crankshaft:

A crankshaft is a rotating shaft which (in conjunction with the connecting rods) converts reciprocating motion of the pistons into rotational motion. Crankshafts are commonly used in internal combustion engines and consist of a series of cranks and crankpins to which the connecting rods are attached.

Connecting rod and Endcap:

Connecting rod, is the part of piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converets the reciprocating motion of the piston into the rotation of the crankshaft. End cap is a part of connecting rod.

Wrist Pin:

In IC engines the Wrist pin is also known as Gudgeon pin it connects the piston to the connecting rod, and provides a bearing for the connecting rod to pivot upon as the piston moves.

Cad Model:

Conditions/Parameters:

Wrist Pin Offset - The position of the wrist pin is going to be varied as followed. But the center of the axis of the piston head and the crank are coincident to each other (i.e) They are on the same plane in all the three cases.

"0" mm Offset - Run a simulation as seen in the video.

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

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

Graphs:

Case 01: Wrist Pin Offset = 0

Case 02: 10 mm Positive Wrist Pin Offset = 0

Case 03: 10 mm Negative Wrist Pin Offset = 0

Conclusion/Result :

Linear Displacement increases as we move from negative wrist pin offset to positive pin offset.

1.At 0 mm offset: 302.708

2.At 10 mm positive offset: 302.522

3.At 10 mm negative offset: 302.521