Exploring the Different Types of Automobile Engines: A Comprehensive Classification

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Introduction

All cars have engines, which provide the energy needed to move the vehicle. The development of diverse car engine types can be attributed to the evolution of automotive engineering over time. Auto enthusiasts, mechanics, and anybody else with an interest in cars should all be aware of these engine types. We will explore the many kinds of automobile engines in this blog, including their functions,benefits, and uses.

Classification of automobile engines

Automobile engines are classified on the following basis.

1.Number of Cylinders

An engine may be a single-cylinder engine or a multi-cylinder engine. In a single-cylinder engine there is only one cylinder, whereas in a multi-cylinder engine there are more than one cylinders.The pistons of all the cylinders are connected to the common crankshaft. Therefore, engines may be:

1.Single cylinder engine

  1. Air-cooled single cylinder produces its combustion only from one cylinder.
  2. They are quite easy to work with since they are not complicated in design and construction as compared to many-cylinder ones.
  3. They are most likely employed in a variety of small power sources such as an engine for a motorcycle or a lawnmower, among others.
  4. Single cylinder motors generally prove to be lighter, more compact, and cheaper to buy than multi-cylinder engines.
  5. Such engines in general are weaker and less torquey than multi-cylinder engines of the same size, even with the best tuning.

2.Multi cylinder engine

  1. A multi-cylinder engine has more than one cylinder, placed in the different layouts, like the inline, V-layout, flat, and radial.
  2. These machines employees can be designed with four, six, eight, or more cylinders with cylinder arrangement depending on the application and the performance desired.
  3. Multi-piston engines are widely applied in cars, trucks, planes, yatchts, and more powerful generators.
  4. They offer efficient economy of operation, have higher kW output, and better torque as compared to engines with a single cylinder.
  5. Because multiple cylinders and more parts make them that much convoluted, multi-cylinder engines are bulkier, larger and therefore often pricier.

2.Cylinder Arrangement

1.In-line Cylinder Engine

  1. An in-line cylinder engine, also known as an inline engine or straight engine, is a type of internal combustion engine where the cylinders are arranged in a straight line along the crankcase. Each cylinder has its own piston, and they are usually connected to a common crankshaft.
  2. The in-Line cylinder engine is a multi-cylinder engine, with all the cylinders arranged in one straight line. Each cylinder has an independent crank.
  3. In an in-line cylinder engine, the cylinders are aligned in a row, either vertically or horizontally, depending on the engine's design. For example, in an inline-four engine, there are four cylinders arranged in a straight line.

2.V Cylinder Engine

  1. A V cylinder engine, also known as a V-engine, is a type of internal combustion engine where the cylinders are arranged in a V-shaped configuration when viewed from the front or rear of the engine. This configuration allows for a more compact design compared to in-line engines while providing good balance and performance. Here are some key points about V cylinder engines.
  2. In a V cylinder engine, the cylinders are arranged in two rows, with each row forming a V shape. The angle between the two rows can vary, commonly ranging from 60 degrees to 90 degrees, although other angles are also used in specific engine designs.

Below there is a some common types of V cylinder engine.

  • This configuration has six cylinders arranged in two rows forming a V shape. V6 engines are widely used in passenger cars, SUVs, and some trucks due to their balance of power and relatively compact size.
  • With eight cylinders arranged in a V shape, V8 engines are known for their high power output and performance. They are commonly used in sports cars, luxury vehicles, and larger trucks.In the V-8 engine design there are two blocks inclined at 90° to each other and each block has four cylinders.
  • V10 and V12 are the most common configurations but are used in some high-performance sports cars, supercars, and luxury vehicles where a higher number of cylinders is desired for increased power and smoothness.Below figure represent the V engine configuration.
Figure 1

3.Valve Arrangement in Cylinder Head Assembly

1.T-head Engine

  1. In this T Head engine the intake valves are always found on one side of the cylinder and the exhaust valves at the opposite side which will show the T shape of the valves when you look at the engine from the top.T Head engines are older designs where the valves are perpendicular to the cylinders. This engineering solution was applied to the early automotive engines. The design had a simple structure, so the engine could be maintained with ease. The airflow was limited compared to the modern engines. They had less efficient combustion as well.
  2. In the T-head engine the valves are arranged as shown in Fig. 2. The suction valve (SV) and the exhaust valve (EV) are on the cylinder block in opposite directions.
Figure 2

2.F-head Engine

  1. These engines are OHV as well as the OHC engines. Intake valves are overhead in cylinder head and exhaust valves are in the engine block (overhead valve).FA integer engines provide more air flow and combustion efficiency than T integer, but limited by exhaust valves in engine block, so cannot influence exhaust flow.
  2. In the F-head engine one valve is in the cylinder block and the other valve is in the cylinder head as shown in Fig. 3.
Figure 3

3.L-head Engine

  1. L Head engines, also known as flathead engines, have both intake and exhaust valves located in the engine block beside the cylinders, with the valves operated by a single camshaft located in the block.L Head engines were popular in early automotive designs due to their simplicity and compact size. However, they are less common in modern engines due to limitations in airflow and combustion efficiency.Simple design, compact size.Limited airflow and combustion efficiency compared to overhead valve designs.
  2. In the L-head engine the suction and exhaust valves are arranged side by side in the cylinder block as shown in Fig. 4.
Figure 4

4.I-head Engine

  1. The valves are either in the intake or in the exhaust position and are positioned in a line (inline).I Head engines deal with each cylinder sharing the same cylinder head, which is commonly seen in inline layouts. This design deliver the desired intake and exhaust flow are superior to those with T and F Head designs. Manual operation of the device may require complexities such as that of valve arrangements hence maintenance of the device may be more involved.
  2. In the I-head engine the suction and exhaust valves are arranged in the cylinder head as shown in Fig. 5.
Figure 5

5.Overhead Engine

  1. Overhead engines have the valves located in the cylinder head, either operated by pushrods and rocker arms (OHV) or directly by camshafts (OHC or DOHC).Overhead engines are modern designs where the valves are situated above the cylinders, allowing for better intake and exhaust flow control.
  2. In the overhead engine the suction and exhaust valves are arranged in the cylinder head. The cylinder head has a hemispherical shape as shown in Fig. 6. The difference between the I-head and overhead valve engines is that the I-head valves are actuated by push rods whereas the overhead valves are actuated by the cams located above the cylinder head.
Figure 6

6.Air-cooled Engines

  1. Air-cooled engines are designed to dissipate heat through air circulation without the need for a separate cooling system like a radiator or coolant.Air-cooled engines have cooling fins on the external surfaces of the engine block and cylinder heads. These fins increase the surface area, allowing heat to dissipate more efficiently.They are relatively simple in design compared to water-cooled engines, with fewer components such as water pumps, radiators, and coolant hoses.
  2. Due to the absence of a liquid cooling system, air-cooled engines are often lighter, making them suitable for applications where weight is a concern.They are commonly used in small engines such as those found in motorcycles, small aircraft, lawnmowers, and portable generators.
  3. Air-cooled engines have fins to radiate heat into the surrounding air. The fins are made triangular in shape as they increase the Cooling surface area. These fins are made of aluminum, which is a good conductor of heat. Air-cooled engines run at higher temperatures because air is not a good conductor of heat. Figure 7 shows an air-cooled engine.
Figure 7

7.Water-cooled Engines

  1. Water-cooled engines use a liquid coolant (usually a mixture of water and antifreeze) circulated through a cooling system to regulate engine temperature.Water-cooled engines have a radiator, water pump, coolant hoses, and a thermostat to regulate coolant flow and engine temperature.The liquid coolant can absorb more heat compared to air, providing efficient cooling even under heavy loads or in hot climates.
  2. Water-cooled engines can maintain more consistent operating temperatures, which is crucial for engine performance and longevity.They are commonly used in automobiles, trucks, industrial machinery, and high-performance vehicles.
  3. Water-cooled engines require circulation of water. All automobile engines,which are water-cooled,are fitted with radiators as shown in Fig. 8. The radiator offers resistance to the flow of air through the passages in between the small diameter tubes carrying hot water.
  4. Therefore an induced draught fan is provided at the back of the radiator. This fan creates the pressure difference required to get an increased flow of air. Similarly, to get pressure difference and to overcome the resistance in the water flow at the jackets of the engine, a water pump is provided which draws water from the radiator and forces it into the water jacket of the engine.
  5. Water is not allowed to rise to a higher temperature, as at higher temperatures scale formation takes place.Scale formation causes local heating due to poor cooling as scales are bad conductor of heat. Such local heating may lead to detonation, which may damage engine parts.
Figure 8

8.Gasoline Engine

  1. A gasoline engine, also known as a petrol engine, operates by igniting a mixture of gasoline and air to produce power.Gasoline engines use spark plugs to ignite the air-fuel mixture in the combustion chamber.They require a fuel delivery system, typically consisting of a fuel pump, fuel injectors (in modern engines), and a fuel tank.Gasoline engines usually have a lower compression ratio compared to diesel engines, requiring a spark to initiate combustion.
  2. Gasoline engines tend to produce less noise and vibration compared to diesel engines of similar size and power output.
  3. In the gasoline engine, gasoline (petrol) is used as fuel. A mixture of gasoline and air is prepared outside the cylinder and an electric spark plug is used to initiate combustion of the compressed charge.

9.Diesel Engine

  1. The diesel engine utilizes a compressed mixture of air and diesel prepared inside the cylinder as fuel. The heat of compression is utilized to initiate combustion of the mixture.A diesel engine operates by compressing air in the combustion chamber to a high temperature, causing diesel fuel to ignite without a spark.Diesel engines rely on high compression ratios to ignite the fuel, eliminating the need for spark plugs.
  2. They use fuel injectors to deliver precise amounts of diesel fuel into the combustion chamber.Diesel engines are known for their high torque output, making them suitable for heavy-duty applications such as trucks, buses, and industrial machinery.
  3. Diesel engines tend to be more fuel-efficient than gasoline engines, especially in applications with constant or high loads.

10.Gas Engine

  1. In the gas engine combustible gases are used as fuel. These engines are not commonly used in automobiles.A gas engine, also known as a natural gas engine or methane engine, uses natural gas as its primary fuel source.Gas engines operate using natural gas, which is typically composed of methane and may include other hydrocarbons.
  2. They require a fuel delivery system designed for natural gas, including gas storage tanks, regulators, and fuel injectors.Gas engines may use spark ignition (similar to gasoline engines) or compression ignition (similar to diesel engines) depending on the design and application.
  3. Natural gas is considered a cleaner-burning fuel compared to gasoline or diesel, resulting in lower emissions of pollutants such as carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM).

Use of engine

  1. Two-stroke cycle gasoline engines with petrol lubrication are used in light duty automobiles like mopeds, scooters etc.
  2. Two-stroke cycle diesel engines with pressure lubrication are used in medium duty automobiles like tempos etc.
  3. Four-stroke cycle gasoline and diesel engines with splash and pressure lubrication are used in heavy duty automobiles like trucks, buses, delivery vans etc.
  4. Cars are provided with four-stroke gasoline engines with splash and pressure lubrication systems.
  5. The inline engine is vertical, i.e. the stroke of the pistons is vertical. Such inline vertical engines are used in cars, buses, trucks etc.
  6. V-engines have cylinders at 90° and are used in heavy duty motor cycles, which are designed for long run.
  7. Single-cylinder horizontal engines are used in scooters and mopeds. This engine is so located that the cylinder head is towards the front of the scooter or moped.

Conclusion

The automotive sector has been dynamically developing, and the innovations aimed at the engines have become more and more energy-efficient, powerful, and environmentally friendly. Knowledge of different automobile engines types is obligatory for engineers, manufacturers and consumers as well at we work towards a cleaner and more efficient transportation system of the future. Whether it's the conventional gasoline engine, the novel system of hybrid technology, or the pollution-free electric motor, every variant of an engine type comes together to form the enormous field of automobile engineering.
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