Production of Piston Using Silicate Bonded Core
ABSTRACT
Production of Piston using Silicate bonded cores was carried out in this project. The molding sand and silicate bonded core was prepared by mixing silica sand, sodium silicate (light) and the mixture was allowed for 24 hours in the atmosphere to enhance the reaction of the mixture with carbondioxide, aluminum scrap was malted in a crucible furnace charcoal fired to produce molten aluminum. Molten aluminum was the poured into the already prepared mold through the sprue and the set up was allowed to solidify. After that a fettling operation was carried out to produce a sound casting.
CHAPTER ONE
1.0 INTRODUCTION
The piston is effectively a pressure-tight plunger that slides up and down in the cylinder. The piston converts the pressure created by the combustion process into a reciprocating mechanical movements. The piston is therefore exposed to extreme forces and temperature during combustion.
By connecting a reciprocating piston to a crankshaft with a connecting rod, the reciprocating movement is connected into rotational movement of the crankshaft. The crown forms the upper surface on which the combustion pressure acts. The force created due to combustion is equal to the cross-sectional area of the cylinder multiplied by the gas pressure. This force which acts along the entire line of the cylinder is transmitted through the structure of the piston to the gudgeon pin bosses and through the gudgeon pin to the connecting rod. (Hillier et al., 2002).
In an engine its purpose is to transfer from expanding gas in the cylinder to the crankshaft through piston rod and or connecting rod. As an important part in an engine piston endures the cyclic gas pressure and inertia forces at work and this working condition may cause the fatigue damage of the piston (Murthy, 2002).
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During the greater part of the power stroke the connecting rod operates at an angle to the centre-line of the cylinder. This cause a side force to be applied by the piston to the cylinder wall. It is therefore necessary to provide bearing surfaces on the piston to carry this side force. These bearing surfaces are formed on the piston skirt.
To allow the piston to move freely in the cylinder, the piston must have a small clearance. To reduce the leakage due to the clearance, piston rings are fitted into grooves formed on the piston just below the crown. The rings are usually made of selected steel materials and they have a characteristic similar to springs i.e the rings will tend to expand out so that they closely contact the cylinder wall. (Murthy, 2002)
1.2 THE BACKGROUND OF THE PROJECT
The background of the project is to produce a piston using a silicate bonding core that will benefit engine balancing, and that will have the below points of consideration.
- Have enormous strength to withstand the high pressure.
- Have minimum weight to withstand the inertia forces.
- Form effective oil sealing in the cylinder.
- Have sufficient support for the piston pin and sufficient rigid construction to withstand thermal and mechanical distortion.
- Have a high speed reciprocating without noise and also provide sufficient bearing area to prevent undue wear.
1.3 STATEMENT OF PROBLEM
Early piston were produce from cast iron, but the purpose of engine balancing a lighter alloy could be used. Cast iron is relatively heavy, rather brittle and cable to develop cracks, additionally cast iron is not particularly good conductor of heat. However, piston cast form aluminum has better strength, and fatigue life and better engine balance.
1.4 AIM OF THE PROJECT
Against the background of the problem stated above, the aims of this project are:
- To produce piston which shall be of use in the automobile industries. .
- To help students get more acquainted with material identifications, applications and operations.
- To produce a product which can in effect reduce over-dependency on foreign countries.
- To reduce environmental pollution by recycling or using aluminum waste that are littered in the environment.
1.5 SIGNIFICANCE OF STUDY
With high rate of piston malfunction and cost used in production. The production of the piston using bonding silicate core (casting) will reduce the production cost and help improves quality. Lifespan, engine balancing, strength, minimum weight to withstand the inertia forces and to promote engine and proper functioning.
1.6 LIMITATIONS AND SCOPE OF THE PROJECT
This projects covers only production of piston using silicate bonded cores.
