Overview of Car Engine Parts
There are so many car engine parts making car engines generate power to run vehicles on road. The main function of the car engine is to generate power from the fuel to move the car. To achieve this, several individual parts work in the car engine. Each car engine parts play an important role. These parts require in good condition for proper working.
Basic behind Car Engine
The car engine is a kind of heart for the car. We can say the Engine is the main part of the car or any other automobile. But the design of the engine is complex to understand.
In an SI Engine compression of the air-fuel mixture creates the pressure and temperature to burn the air-fuel mixture by the spark from the spark plug. In CI Engine, only compression of air creates high air temperature and spraying fuel from the fuel injector generates power.
To generate this power and withstand the load, it is necessary to become a car engine robust in structure. It consists of two main and heavy components like a cylindrical block and a cylindrical head. The cylinder head can attach to the cylindrical block.
The cylindrical block supports the piston, crank, crankshaft, connecting rod, crankshaft, and oil sump to rotate the piston in the cylinder to generate power. While the cylindrical head supports camshaft, cams, inlet, and outlet valves to open and close when the air-fuel mixture comes into the combustion chamber.
Today’s advanced technology makes the engine more efficient work. In this article, we are going to see the car engine parts names with pictures. diagrams, construction, working, material composition, and use.
Car Engine Parts Diagram
Car Engine Parts Names
- Engine Block
- Cylinder Head
- Piston Ring
- Combustion Chamber
- Cylinder Lining
- Gudgeon Pin
- Connecting Rod
- Crank Shaft
- Timing Belt/Timing Chain
- Serpentine Belt
- Oil Pan
- Valves, Valve Springs & Rocker Arm
- Spark Plug
- Fuel Injector
In this article, we will also find an answer to why a piston has a piston ring & why the crankshaft is bigger at one end?
All Car Engine Parts with their Functions
All car engine parts names with pictures are explained below with their function, constructional details, working, and materials.
The engine block is the main supporting structure of the Engine where combustion action takes place. It is made by the casting as a single unit. In most cases, cast iron & Aluminium alloy is the main choice for the engine block.
The engine block contains 6, 8, 12, or 16 main holes for fixing & reciprocating pistons in it. They have various small holes through which water & oil flow from pipes to cool & lubricate the engine.
The engine block holds pistons, crank, crankshaft, crankpin, connecting rod, and other parts in it. These parts convert the reciprocating action of the piston into rotary motion.
Whereas the engine used in motorcycles has a bit different engine block (Mostly referred to as Cylinder Block). This cylinder block has fins attached outwards. It helps to increase the contact area between the cylinder and air-flow outside.
When the motorcycle is moving at high speed creates forced air circulation around Cylinder Block. Which apparently, causes an increase in the cooling rate of the cylinder block.
The cylinder head is attached to the engine block from the top side, with help of a gasket and bolts. This gasket prevents the leakage & losses of the gases & heat from the cylinder.
The cylinder head provides an inlet & outlet for the air and exhaust gases. It is made in a single unit by the casting process.On the cylinder head, assembly of the valves, valve springs, pushrods, lifter, camshaft, cams, and rocker arm presents.
This assembly regulates the airflow or air+petrol flow inside the cylinder during the intake stroke and helps to remove exhaust gases from the cylinder during the exhaust stroke.
Cylinder blocks can be further classified into different types depending upon the valve and port configuration: Loop flow type, Offset cross-flow type, and Inline cross flow type.
The piston is the cylindrical component guided in the engine block with a crank & connecting rod to reciprocate in the cylinder. Pistons are strong enough to withstand the high temperature generated due to combustion. So, these pistons are mainly made by casting or forging cast iron or aluminum alloys.
The function of the piston is to compress the air or air-fuel mixture into the cylinder. Pressure energy generates due to this fuel combustion, and the piston converts this energy into useful mechanical power.
Piston transfer this power through connecting rod and crankshaft to run the vehicle.Piston reciprocates very fast into the cylinder. So it is not solid completely. It is made with a precise tolerance with a high finish to reciprocate into the cylinder.
Generally, the piston is not made with a tight fit or loose fit to reciprocate inside the cylinder. Because due to the tight fit, there are chances to stick the piston into the cylinder. And due to loose fit, it may leak the gases from the cylinder.
To prevent these losses, piston rings are used with the piston. Piston rings give a great sealing fit between piston & cylinder. These piston rings are manufactured in cast iron with a fine grain structure with high elasticity.
Due to that, piston rings are not affected by high heat.
There are three types of piston rings.
- Temperature Ring- In a Car engine, high temperature develops due to the combustion of fuel inside the cylinder. The function of the temperature ring is to resist high temperatures.
- Compression/Pressure Ring- Due to the creation of high temperature, it develops high pressure. This pressure ring is designed to bear this high pressure.
- Oil Control Ring- This ring prevents oil leakage between piston and cylinder.
Why does a piston have piston rings?
One of the biggest reasons behind using piston rings on the piston is thermal expansion.
When the temperature of the body increases, its volume increases too. When the piston inside the cylinder starts expanding due to thermal expansion, it will apply force on the cylinder block. It causes wear of cylinder block.
Piston rings eliminate this problem. Here piston is originally kept smaller in diameter to keep the clearance between piston and cylinder. This clearance fills with piston rings.
When the heat generated through power stroke starts affecting piston and piston rings, they both start to expand their shape. The piston will fill the gap between the piston and cylinder.
Whereas the ring is not a complete circle, it also has a small gap. Hence when the ring expands, it doesn’t cause the wear on the cylinder and fills this gap instead.
The combustion chamber is the area present inside the cylinder. This area is defined by the position and size of the piston in the cylinder. This air-fuel mixture comes from the inlet valve & gets ignited.
When the piston moves from the Bottom Dead Centre to the Top Dead Centre, it causes compressing of the air-fuel mixture. Once the piston starts reaching its TDC, the spark plug ignites the mixture & produces energy. This energy pushes the piston to BDC.
The same process happens in the Diesel engine. But instead of the air-fuel mixture, only air comes into the combustion chamber and is compressed to a high temperature. Instead of the spark plug, the fuel injector injects diesel into it & gets it to burn to produce energy.
Combustion of the fuel depends upon the compression ratio. It is different for SI & CI engines.
To form a cylinder, cylinder liners fit into cylindrical cylinder blocks. It makes the internal part of the cylinder fine to reciprocate piston into it. It gives a fine sliding surface to the piston. Cylinder lining and piston ring capture lubricant between them for lubrication purposes.
Cylinder lining helps to transfer heat from the piston to the coolant.
A Gudgeon pin is also known as a wrist pin. It is hollow in the construction. It using to connect the piston to the connecting rod to transfer motion. Gudgeon pin is imposed by the load due to reciprocating motion & temperature due to rotation of the connecting rod and piston.
In the car engine, the gudgeon pin is made with the forged steel alloy or Titanium Pin (Low Density). It is designed to bear the shear & bending stresses.
Connecting rods using to connect the piston with the crankshaft to transfer reciprocating motion. They are made in such a way that, a small part connects to the piston & the large part connects to the crank. A Gudgeon pin connects a small part, and a crankpin connects a large part.
Connecting rod is the part that transmits piston motion to the crank. Later, this motion is converted by the crankshaft into rotary motion. Connecting rod is made up of forged steel.
Connecting rod is connected to the crankshaft by the crank with the help of a crank pin. The crank helps to convert and transfer reciprocating motion into rotary motion.
The crankshaft is supported by the engine block inside it. The reciprocating motion generated by the piston due to the combustion of fuel gets transferred via connecting rod into the rotary motion of the crank.
As we know, the crank is part of the crankshaft. Hence, rotary motion is directly transferred to propel the automobile. Crank is made by the forging process of steel alloy.
Why crankshaft is bigger at one end?
Piston-connecting rod-crankshaft mechanism operates at very high speed. During this, the piston reciprocates and has its linear momentum. It causes the piston to pull everything upward, and therefore vertical shaking of the whole engine.
To eliminate this shaking of the engine, we need to provide extra weight on the crankshaft on one side. Due to this weight, when the piston goes to the top dead center (TDC), this weight on the crankshaft goes downward. The momentum of both forces cancels each other providing us with a smooth ride. But the problem does not end here.
Let’s explain why. Because of this attached extra weight on the crankshaft, we eliminated the engine shaking in the vertical direction. But the engine delivers us the horizontal shaking problem.
To defend against such kind of shaking, we need one more shaft with more weight. This one is called a counter crankshaft. It helps in stabilizing the engine even more.
Timing Belt/Timing chain
As the name says, the timing belt connects various parts of the IC to operate at its required time. It helps to rotate the crankshaft and camshaft, which synchronizes the timing of the inlet and exhaust valves of the IC engine as per the strokes.
The timing belt is flat from one side and has a tooth on the other side. These teeth get to engage with the rotating gears of various parts like the crankshaft and camshaft to transfer motion to different engine parts.
The timing belt is less expensive, occupies less space, is more efficient, is light in weight, and does not create noise. These belts do not require any oiling or lubrication like chain belts. So, it is better than the timing chain.
As per the manufacturer, it is necessary to replace the timing belt after a specific period for better performance. Breaking the timing belt can cause severe damage to the engine. It is advisable to replace the water pump and other parts with the timing belt to reduce excess cost.
A serpentine belt is a single, continuous belt used to drive multiple peripheral devices in an automotive engine, such as an alternator, power steering pump, water pump, air conditioning compressor, air pump, etc.
The belt is guided by an idler pulley and a belt tensioner. The belt tensioner may be hydraulic, spring-loaded, or maybe manual, depending upon the type of application.
The serpentine belt is used on the exterior of the engine. It is also called an accessory belt, alternator belt, or fan belt because it is used to drive various other accessories. In modern vehicles, only one belt is used to drive all other accessories by multiple idler pulleys.
If a serpentine belt in the car fails or breaks, all things will stop working, such as power steering, air conditioning, and the battery will also die. It can damage our car engine also. So, it is essential to inspect the serpentine belt at a predecided time and change it as per standard guidelines.
The oil pan is the bottom half of the crankcase. Another name for the oil pan is oil sump. All car engine parts require lubrication to reduce the friction between them.
It causes to run all engine parts to run smoothly. Otherwise, friction can reduce the life of the car engine parts and reduce the efficiency of the car engine.
After the lubrication of the engine parts, it collects into the sump. It is mainly for the collection of lubricating oil.
The oil pan and the lower part of the cylinder block together are called the crankcase. It contains a crank & crankshaft. Its main function of it is to provide bearing support to the crankshaft. The crankcase prevents the engine parts from dust particles. It is made up of grey cast iron or aluminum.
In the two-stroke engine, the air-fuel mixture passes through the crankcase to the combustion chamber. The oil sump is not present in the two-stroke engine.
As we know, the speed & torque produced by the car engine is not uniform in nature. Due to that vehicle will not run at a uniform speed. So, it will affect the life of the other parts due to fluctuation. A flywheel is used to avoid this.
There are two main functions of the flywheel.
- It stores the energy generated in the power stroke to use in the preparatory stroke.
- It makes the rotation of the crankshaft uniform.
The flywheel is mounted on the crankshaft. It balances the speed of the vehicle.
Depending upon the number of cylinders and the construction of the engine, flywheel size gets varies.
Valves, valve springs & rocker’s arm
On the top of the cylinder head, two openable holes are there for inlet & outlet purposes. From the inlet air-fuel or air comes inside the combustion chamber & from the outlet, exhaust gases drain out. It is regulated by the valve & valve spring mechanism.
This valve & valve spring are operated by the rocker’s arm. As per the timing of the camshaft rocker arm push the valves to open & close.
When these valves are in a close position, it gives very tight sealing to avoid losses or leakage.
Poppet Valve- The poppet valve operates with the rocker arm and spring. When the camshaft rotates due to the shape of the cam, the poppet valve opens and closes. It has a stem connected to the head at an angle of 45 degrees.
Sleeve Valve- The sleeve valve is the part of the cylinder, and it fits into the cylinder wall. Sleeve valves help to transfer air-fuel mixture flow from crankcase to cylinder during combustion in two-stroke engines.
Rotary Valve- The rotary valve regulates the gas or air-fuel mixture through the pipes.
Cam is the egg shape round steel plate mounted on the camshaft. The main function of the cam is to control inlet and outlet valve timing. This all is depending on its shape. Cam is an integral part of camshafts.
When the camshaft rotates, as per the design of the shaft, the cam rotates & lifts the rocker arm to push the valve to open. Cam is made of steel alloy to resist friction.
The location of the camshaft varies as per the type of vehicle or design. In some vehicles, it mounts in a cylinder head, or in some cases, it mounts in an engine block. They are guided by a series of bearing.
It is a shaft on which cams are mounted at a specific distance to open valves. The camshaft is driven by car engine speed to rotate. It regulates the opening & closing timing of the inlet & exhaust valves. Its material is a steel alloy.
The intake manifold is the series of pipes connected to supply air-fuel mixture or air into the combustion chamber. In the diesel engine, instead of an air-fuel mixture, only air is supplied into the combustion chamber.
The exhaust manifold is the same as the inlet, but it is for draining exhaust gases generated after the combustion. The function of the exhaust manifold is the same in SI & CI engines.
In the car engine parts, the gasket is the important part. It gives airtight sealing between
- The engine block & cylinder head.
- Inlet manifold with the cylinder head.
- Outlet manifold with the cylinder head.
Due to the gasket, there are no chances of leakage or any loss.
A spark plug is the main part of the Self Ignition Engine. And spark plug must operate under the most severe conditions. When the air-fuel mixture comes from the inlet valve, then it compresses inside the combustion chamber.
Once the piston going to reach TDC, the spark plug ignites the mixture to produce energy. Without a spark plug, the SI engine does not work.
The fuel Injector is the primary part of the Compression Ignition Engine. When air comes from the inlet valve into combustion, then it gets compressed with the help of a piston. Once the piston going to reach TDC, the fuel injector injects the fuel. Due to the high temperature of the air, it burns to generate energy.
1. Engine block
2. Cylinder head
4. Connecting rod
10. Spark plug (SI Engine)
11. Fuel Injector (CI Engine)