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How 8 Cylinder Engine Works?

Overview

The 8 cylinder engine is called V8 because of the shape of the motor, which has the cylinders grouped in four pairs with the shape of a “V”, staked one after the other. Each cylinder has a piston inside, which moves up and down during the process of combustion. This engine is characterized as more powerful than the V4 and V6 motors and it is one of the best engine designs of all time.

Combustion Process

Carburetor

The carburetor is located in the top, central part of the engine. The gasoline is pumped from the gas tank into the carburetor. Inside, the gas is mixed with air to create an explosive mixture of both. The accelerator is connected to a valve, called throttle, inside the carburetor. As you press down the accelerator, the throttle opens more and allows more fuel to pass through. This speeds up the engine. As you decelerate, the throttle closes and the engine slows down.

Valve Trains

The valve trains let air and fuel from the carburetor into the cylinders and exhaust the remaining gases of the combustion process out of the engine. They are located on top of the cylinders, making the “V” shape taller. There is one intake valve and one exhaust valve for each cylinder. The air goes inside the cylinders through the top, inner sides of the cylinder head. The remaining gas of the combustion goes out of the engine through the exhaust valves, located on the outer sides.

These valves are activated by the metallic rods, which push the rocker arm and the valve open. Their movement is controlled by the camshaft, which is a horizontal bar on top of the motor. The Camshaft is driven by the crankshaft, using a belt or chain. It rotates at half the speed of the crankshaft.


Cylinders and Pistons


Each cylinder contains a piston inside, which moves up and down twice for each combustion. The first time a piston moves down, it lets a mixture of air and fuel into enter the cylinder through the intake valve (intake stroke). Then the intake valve closes and the piston moves upward, compressing the mixture of fuel and air so that the combustion becomes stronger (compression stroke). Next, the spark plug ignites the mixture of air and fuel and the explosion moves the piston downward (power stroke). Finally, the piston moves upward as the exhaust valve opens and lets the remaining gas out (exhaust stroke).

When the engine is working, the pistons are moving constantly and uninterruptedly. Their movement is synchronized so that the engine runs smoothly. The order in which each piston reaches the top varies in different kinds of V8 engines.

Crankshaft

The crankshaft is a bar with discs that is connected to the pistons by connecting rods. It is located in the bottom of the motor and its main purpose is to convert the vertical motion of the pistons into rotary motion. Its discs have a counterbalance in order to avoid movement of the engine as the pistons move. When a piston is upward, the counterbalance of its disc in the crankshaft is in the opposite direction.
When the crankshaft is responsible of making the vehicle advance with the energy generated by the engine. As it rotates, it transmits that rotation further on to the flywheel, the gearbox, the main shaft, the differential, and the wheels of the car.

Additional Systems

Lubrication System

The oil pan is located beneath the engine and contains the oil needed to lubricate its components. The oil pump starts working with the engine and sends oil to the filter, which removes the dust particles from the oil. Then, the oil is sent through two main passages: one to the crankshaft and cylinders and the other one to the camshaft. Finally, the oil is then returned to the oil pan through different passages.

Electrical System

The battery provides electricity to the booster coil, which increases its voltage high enough to produce a spark. Then the coil sends it to the distributor. As the rotor inside the distributor turns, it touches a series of contacts and sends the current to the spark plugs, located in the cylinder heads. These spark plugs will create a spark in the cylinder that ignites the compressed air and fuel mixture and start the power stroke of the piston.

Cooling System

The water pump is driven when the motor is working. It sends the coolant from the lower tank of the radiator to the engine. The engine has hidden passages in its perimeter to allow the coolant to pass through and absorb part of the heat generated by the combustion process. Then the coolant is pumped to the upper tank of the radiator. It has to pass through a thermostat, which won’t allow coolant in until it reaches a certain temperature. Once inside the upper tank of the radiator, the coolant heads to the lower tank passing through an area, ventilated by the air that is dragged by the fan that cools the engine. The fan is located in front of the motor and behind the radiator. It rotates because it is attached to the crankshaft.


Gasses from Combustion

The gas that comes out of the exhaust valve goes through a pipe to the catalytic converter, where it is cleaned so that it become less harmful for the environment. The air then goes through another pipe to the muffler, which contains different chambers inside that reduce the noise produced by the combustion. Finally, the air escapes through the tail pipe.

Conclusion

The technology of a V8 motor is very impressive. People might try to minimize this technology because it was created many decades ago, but it is very efficient and extremely complex. Designing a V8 motor for the first time implied knowing a lot about mechanics, engineering, and even physics. It is so complex that there have been cases of people that disassemble the components of the V8 engine and when they try to assemble them again, they find pieces left over. It is a technology so complex and well designed that it is still being used and it will always have its place in history.

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