MBD Simulation on a Piston Assembly

Aim: Design and Motion Simulation of Piston Assembly using Solidworks.

Theory: Piston-Crank Mechanism is a demonstration of a simple mechanical system of linkages and motion chains.The objective is to display the working of a piston inside an engine cylinder and how the reciprocating motion of the piston gets converted to the rotational motion of the crank.

It consists of the following parts:

• Connecting Rod
• Crank
• End Cap
• Gudgeon Pin
• Piston

Connecting Rod: A connecting rod, also called a con rod, is the part of a piston engine that connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the crankshaft.

Crank: The crankshaft is a moving part of the internal combustion engine (ICE). Its main function is to transform the linear motion of the piston into rotational motion. The pistons are connected to the crankshaft through the connecting rods. The crankshaft is mounted within the engine block.

End Cap: The small end of the connecting rod connects to the piston with a piston pin .The piston pin provides a pivot point between the piston and connecting rod. The rod cap is attached to the connecting rod with two cap screws for installation and removal from the crankshaft.

Gudgeon Pin: The gudgeon pin is typically a forged short hollow rod made of a steel alloy of high strength and hardness that may be physically separated from both the connecting rod and piston or crosshead. The design of the gudgeon pin, especially in the case of small, high-revving automotive engines is challenging. The gudgeon pin has to operate under some of the highest temperatures experienced in the engine, with difficulties in lubrication due to its location, while remaining small and light so as to fit into the piston diameter and not unduly add to the reciprocating mass. The requirements for lightness and compactness demand a small diameter rod that is subject to heavy shear and bending loads, with some of the highest pressure loadings of any bearing in the whole engine. To overcome these problems, the materials used to make the gudgeon pin and the way it is manufactured are amongst the most highly engineered of any mechanical component found in internal combustion engines.

Piston: A piston is a moving disk enclosed in a cylinder which is made gas-tight by piston rings. The disk moves inside the cylinder as a liquid or gas inside the cylinder expands and contracts. A piston aids in the transformation of heat energy into mechanical work and vice versa.

Piston Assembly:

Procedure:

• At first, we will go for part modelling to design the Piston, Crank, Connecting Rod, Gudgeon Pin, End Сар.
• After we have design them in Solidworks we will go for assembly of the following parts before going for the motion study.
• Now we will apply the motor at the crank axis and apply a rotation of 2000rpm in the clockwise direction.
• Now we will apply contact on all the parts.
• We will gravity downwards.
• Now we are completed will all the things we click on calculate and then after calculation we go for results and plots.
• Now we can simultaneously do the simulation of all the three.

Case 01: 0 mm offset and 2000 rpm in the clockwise direction.

Case 02: 10 mm offset and 2000 rpm in the clockwise direction.

Case 03: -10 mm offset and 2000 rpm in the clockwise direction.

Results:

Case 01: 0 mm offset and 2000 rpm in the clockwise direction.

Case 02: 10 mm offset and 2000 rpm in the clockwise direction.

Case 03: -10 mm offset and 2000 rpm in the clockwise direction.

Superimposed Image:

Observations:

• The linear displacement graph is smooth for all three cases.
• It shows the cyclic movement of the crank.
• It can be observed that the positive offset and negative offset graphs are opposite to each other.

Animation Link: https://www.youtube.com/playlist?list=PLgFSZcr_6Ygw0eRpOgDm1CVWU0wIEH9gA

CAD files link:https://drive.google.com/drive/folders/1h8I6NXuD5UpckoeGrPA-C-zNwK0_StvL