Basic Engineering Terms | Automobile Engineering.

Basic Engineering Terms refer to the definitions and meanings of the engineering terms. In this article, I will discuss the basic meaning of different engineering terms for Automobiles.

Basic Engineering Terms

Basic Engineering Terms

The field of automobile engineering deals with automobile design, development, production, and maintenance. A self-propelled machine used for transportation, typically designed to carry passengers or goods.
In basic engineering terms, several factors are causing the vehicle to run on the road. Some of these are- 

  1. Chassis – The structure or the frame of the vehicle.
  2. Powertrain – The system that delivers the power in the car like the engine, transmission, etc. 
  3. Engine – The device converts fuel into mechanical energy to generate vehicle movement power.
  4. Transmission – It transfers power from the engine to the wheels. 
  5. Suspension System – This system provides a cushioning effect to the driver. 
  6. Steering System – The mechanism that allows the driver to control the vehicle’s direction.
  7. Braking System – This system allows the vehicle to stop. 
  8. Fuel System – The fuel system provides fuel into the engine for combustion. 
  9. Electrical System – This system provides electrical power to the vehicle system. 
  10. Exhaust system – The system directs and channels the exhaust gases from the engine.
  11. Cooling system – This system provides a cooling effect to the drivers and the passengers. 
  12. Aerodynamics – The system that directs and channels the exhaust gases from the engine.
  13. Safety System – Various systems and features are designed to enhance the safety of the vehicle and its occupants, such as airbags, seat belts, anti-lock braking system (ABS), and electronic stability control (ESC).


These terms provide a general overview of the key components and systems involved in automobile engineering. But in this article, I will discuss the other automobile engineering terms, so read this article- 

Basic Engineering Terms – Stroke Length 

Basic Engineering Terms - Stroke Length


Stroke length is the distance between T.D.C and B.D.C. To understand stroke length, it’s important to know the basic operation of a four-stroke internal combustion engine, which consists of four stages: intake, compression, combustion, and exhaust. During the intake stroke, the piston moves downward from TDC to BDC, allowing the air-fuel mixture to enter the combustion chamber. In the compression stroke, the piston moves upward from BDC to TDC, compressing the air-fuel mixture. The combustion stroke involves the ignition of the compressed mixture, resulting in the expansion of gases and the downward movement of the piston from TDC to BDC, generating power. Finally, in the exhaust stroke, the piston moves upward from BDC to TDC, expelling the burned gases from the combustion chamber.
The stroke length is the distance that the piston travels along the cylinder bore between TDC and BDC during the intake, compression, combustion, and exhaust strokes. It directly affects the displacement of the engine, which is the total volume of air-fuel mixture that can be combusted during one complete cycle. The displacement, along with other factors such as the number of cylinders and the engine speed, plays a crucial role in determining the engine’s power output.

Basic Engineering Terms – Cylinder Bore 

Basic Engineering Terms - Cylinder Bore

The cylinder bore is the engine’s displacement, which is the total volume swept by all the pistons in one complete revolution. The displacement, along with other factors such as stroke length and the number of cylinders, affects the engine’s power output and performance characteristics. The cylinder bore is the diameter of the cylinder. 
The cylinder bore is typically measured in millimeters (mm) or inches (in) and is an essential parameter used in engine design and specifications. It directly affects the size of the combustion chamber and the amount of air-fuel mixture that can be combusted during each engine cycle. A larger bore allows for a greater displacement, which can lead to higher power output, while a smaller bore results in lower displacement and potentially better fuel efficiency.

Basic Engineering Terms – Combustion Chamber


Basic Engineering Terms - Combustion Chamber

It is the clearance of space between the piston head and the cylinder head(when the piston is at the T.D.C. position). It extends up to the top compression ring. It contains a pressurized air-fuel mixture. The ratio of different fuels is-
  1. Petrol Engine – 6:1 to 15:01.
  2. Diesel Engine – 16:01 to 28:01.
  3. Gas Engine – 6:1 to 15:01.


The combustion chamber is located within the cylinder head, above the piston, and is formed by the combination of the cylinder head’s shape and the top surface of the piston when it is at the top dead center (TDC). The primary function of the combustion chamber is to facilitate the efficient and controlled combustion process.
The design of the combustion chamber plays a significant role in determining engine performance, fuel efficiency, emissions, and other factors. The shape, size, and various features within the combustion chamber, such as valves, spark plugs, and fuel injectors, all influence the combustion process.

Basic Engineering Terms – Displacement Volume

Displacement Volume is also known as the swept volume. It is the volume swept by the piston while moving from one dead center to another dead center. 
Total volume means- clearance volume + swept volume. 
Displacement volume is determined by two factors: the cylinder bore and the stroke length. The cylinder bore is the diameter of the cylindrical chamber where the piston moves, while the stroke length is the distance traveled by the piston from the top dead center (TDC) to the bottom dead center (BDC) within the cylinder.
To calculate the displacement volume of an engine, the following formula is used:
Displacement Volume = (π/4) x (Cylinder Bore)^2 x Stroke Length x Number of Cylinders.

Basic Engineering Terms – Adiabatic Process

The adiabatic process is such a process in which the heat exchange does not happen with the atmosphere. During an adiabatic process, the energy transfer occurs solely through work done on or by the system.
For example, in the combustion process of an internal combustion engine, the air-fuel mixture inside the cylinder undergoes adiabatic compression, meaning that no heat is exchanged with the surroundings. The rising temperature and pressure result from the compression work done by the piston. Subsequently, during the combustion and expansion phase, the hot gases expand adiabatically, pushing the piston and performing work. Again, no heat is exchanged with the surroundings during this expansion process.

Basic Engineering Terms – Engine Capacity 

Engine capacity is the displacement volume of the cylinder or the cylinders is called engine capacity. Engine capacity is an important parameter that influences the power output, torque characteristics, and overall performance of an engine. In general, a larger engine capacity tends to result in higher power and torque, as it allows for a larger volume of air-fuel mixture to be combusted during each engine cycle. This is why vehicles with larger engine capacities are often associated with higher performance and towing capabilities, such as in sports cars or trucks.
Engine capacity = πr^2LN where, 
  • r – radius of the cylinder. 
  • -Length of the cylinder. 
  • N – Number of cylinders. 
  • π22/7 or 3.14. 



A 4-stroke 4-cylinder engine operates under various conditions. In this article, I have discussed the basic terms of automobile engineering. 
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