MBD Simulation on a Piston Assembly

Aim - To model piston parts & assembly & perform motion analysis for piston assembly.

Introduction & Theory -

Piston assembly consists of a piston, piston rings and piston pin known as gudgeon pin.

It transmits gas force generated during combustion to the connecting rod and crankshaft.As piston is connected to small end of the connecting rod with the help of gudgeon pin. It guides the connecting rod when gas force is transmitted.

Air/fuel mixture is compressed by piston.Piston rings restrict the flow of hot gases into the crankcase. This is also referred as blow by control.Piston rings lubricate the cylinder wall.Piston rings restrict the amount of oil from crankcase into the gap between piston and cylinder head.Heat is transferred to the cylinder wall from piston by piston rings

Construction 0f PISTON assembly :

Connecting rod -

The main function of a connecting rod is to form a link between a piston and crankshaft. A small end of the connecting rod is connected to the piston with gudgeon pin and big end is separated into two parts for ease of assembly with crankpin. The two parts of the big end are bearing cap and big end housing. Both are being bolted together. This is done for ease of assembly of connecting rod with crankpin. To supply oil to the big end, the oil hole is drilled from big end.

Crankshaft -

Crankshaft is the final link in the slider crank mechanism. The linear motion of a piston is converted into rotary motion of a crankshaft. The energy is generated into the combustion chamber by transforming the reciprocating motion of a piston into rotary motion of a crankshaft. Crankshaft consists of two main bearings at the other side of the it, made up in to two half liners. Crankshaft, crankshaft oil seals, main bearings, pulley and vibration damper are parts of crankshaft assembly.

Piston rings -

There are two types of piston rings: compression and oil control ring. Piston rings are generally made up of rectangular section. To prevent sticking of ring into the groove, their inner and outer edges are chamfered.

Piston pin -

Gudgeon pin is the main load carrying part in piston assembly. Small end of the connecting rod is connected to piston with the help of gudgeon pin.

3 D models of piston assembly -

PISTON ASSEMBLY -

RESULTS -

CASE 1

CASE 2

CASE 3