MBD Simulation on a Piston Assembly
AIM
To perform MBD Simulation on a Piston Assembly.
INTRODUCTION
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidiser in a combustion chamber that is an integral part of the working fuel flow circuit. In an internal combustion engine, the expansion of the high temperature and high pressure gases produced by combustion applies direct force to some component of the engine. The force is applied typically to piston, turbine blade. This force moves the component over a distance, transforming chemical energy into useful work.
A piston is a component of reciprocating engine and other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by pistonring. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder.
- Piston Ring.
- Piston Skirt.
- Piston Pin.
- Piston Head/Crown.
- Connecting Rod.
- Connecting Rod Bolt.
- PIston Bearings.
OBJECTIVE
To obtain the linear displacement of piston head in the following 3 cases
additional details
PARTS
CONNECTING ROD
END CAP
CRANK
PISTON
WRIST PIN
PISTON ASSEMBLY
PROCEDURE
- The parts where seperatly desinged according to the dimension.
- The assembly was done using suitable mates. After which the motion analysis is done.
- A motor is applied to the crank shaft at 2000 rpm. Then the contact points where provided (use dry steel as material)
- For detailed result set the frame rate to 12000 frames per sec, to capture each degree of rotation of crank shaft.
- The analysis was done according to the condition (3 cases).
- The linear displacement of piston head was plotted against time for all the 3 cases.
RESULT
CASE 1
Wrist pin offset is zero
CASE 2
10mm positive wrist pin offset
CASE 3
10mm negative wrist pin offset
SUPER IMPOSED PLOT
CONCLUSION
The linear displacement is almost same in all 3 cases
Linear displacements are :
- Case 1 ( 0 mm offset ) - 303.1604000
- Case 2 (10 mm positive offset)- 303.1349618
- Case 3 (10mm negative offset)- 303.1352737
The point of maximum displacement is TDC and the point of minimum displacement is BDC.