1. The Camshaft
Camshaft are usually made from cast forged steel. The surface of the lobes are hardened for long life. In most cases the camshaft is located in the engine block and is supported and rotates, in series of bearings located along its length. It's purpose is to provide for the opening and closing of engine valves.
2. Pistons
When a flammable gas mixture ignited and burns, the gases expand producing heat and pressure. If the heat energy has nothing to work on, it will do nothing more than warm an area. The function of the piston is a hollow metal tube with the top enclosed. It is on this enclosed top that the heat energy works.The gunpowder would drive a cannonball through the barrel of the cannon when fired. If the energy produced by the burning gases is allowed to passed between the pistons and the cylinder walls, it is wasted energy;therefore, you must have a pressure-tight seal between the piston and the cylinder walls.Take a look at the piston as you can see near the top of the piston is series of land grooves.
The Piston
To obtain a pressure tight seal a series of rings is installed into the grooves near the top of the piston. Just below the lands and grooves is hole that extends through the piston. We will discuss the reason for the piston pin hole in more detail later. There are two types of rings compression rings and oil control rings. The top two rings are compression rings and are responsible for forming the pressure tight seal.
The piston moving in the cylinder causes friction. Even though the smooth surface of the cylinder walls helps to reduce the friction, the cylinder walls must be lubricated with oil but we cannot allow excess oil to remain on the cylinder walls. Oil remaining on the cylinder walls would be burned with gases when the piston travels down inside the cylinder. Eventually there would be no more oil to prevent or at excess oil from the cylinder walls as the piston travels downward.
Piston Rings
3.Connecting Rod
So far you have heat energy being converted to mechanical energy by pistons; but like heat energy , mechanical energy must have something to work on. If not, it is wasted. The piston traveling straight down must cause the wheels of the vehicle to rotate. That is the up and down motion (reciprocating motion) of the pistons must be connected to the crankshaft in a way that will allow for this change of motion occur. A component known as the connecting rod does this.
This is where the hole in the side piston is employed. A snug-fitted pin called piston pin is manufactured for this hole. The pin attaches the connecting rod to piston. This is done by inserting the pin through the holes in the side of the piston and through the piston pin bushing (a friction type bearing) located in a hole at the top of the connecting rod. The connecting rod is allowed to swing freely on the piston pin in much the same manner as your hand swing on your wrist. (For this reason, you will often hear the piston pin referred to as the wrist pin). The bottom of the connecting rod is connected to the crankshaft by bearing cap.
Connecting Rod and Related Parts
Okay so what was "reciprocating motion"? Yes, It's an up and down motion. And what delivers the power from the engine? Very good if you said the crankshaft.
4. Crankshaft
As stated previously, the crankshaft delivers power from the engine. The function of the crankshaft when aided by the connecting rod is the change the reciprocating motion of the pistons to rotary motion.The crankshaft extends through the length of the engine and has a series of throws and journal. Some of these journals are on the shaft itself, and others are located on the throws are connecting rod journals to be offset from the centreline of the crankshaft. The main journal cap is bolted over each of the crankshaft's main journals after the crankshaft is positioned in the crankcase.
Crankshaft Construction
The connecting rod journals provide a place to attach the connecting rod to the crankshaft. After the connecting rod is seated on the crankshaft, a connecting rod bearing cap is bolted over the journal to the connecting rod. Therefore when the piston is driven down in the cylinder, it drives the connecting rod, which drives the crankshaft to rotate.
The Crankshaft Changes Reciprocating Motion to Rotary Motion
5. Flywheel
In some engines there is brief interval when the pistons do not drive the crankshaft. However, with enough momentum, the crankshaft can travel through this brief portion of its rotation. To accomplish this, a large wheel known as the flywheel is bolted to the rear end of the crankshaft.
6. Vibration Damper
Under certain engine speeds and loads, the crankshaft tends to vibrate. To reduce this vibration, a small wheel known as the vibration damper is bolted to the front end of the crankshaft. Vibration dampers often serve as pulley for the fan, generator and accessory belts or they may have a pulley attached to accommodate the various belts.
Vibration Damper Location
With the exception of the flywheel and the vibration damper, all the moving parts discussed up to this point require lubrication (engine oil) stored inside the engine oil pan. So let's discuss the oil pan.
7. Oil Pan
The oil pan is the reservoir of the engine oil. It is a large metal pan fitted and bolted to the bottom of the crankcase. It enclose the crankcase and all moving parts. Oil picked up from the oil pan by the oil pump and distributed throughout the engine.
Oil Pan and related Parts.
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