How car engine works? / 4 stroke internal combustion engine (3D animation)

Summary

This video explains the operation of a four-stroke internal combustion engine, focusing on key components like the crank mechanism, valve timing, and ignition system. It describes the engine's four-stroke cycle—intake, compression, power, and exhaust—and how each phase contributes to converting fuel energy into mechanical work. The script also covers engine management, ignition timing, fuel-air mixture, and the role of the engine control unit in optimizing efficiency. The operation of subsystems like intake, fuel supply, and exhaust are also discussed, highlighting the intricate processes that keep the engine running smoothly.

Takeaways

• 😀 The internal combustion engine (ICE) converts the combustion energy of fuel into mechanical energy.
• 😀 A four-stroke reciprocating engine is the most common type used in vehicles, consisting of intake, compression, power, and exhaust strokes.
• 😀 The engine operates using a crank mechanism and valve timing system to convert energy into rotational mechanical work.
• 😀 The four-stroke cycle consists of two crankshaft revolutions and is repeated for continuous engine operation.
• 😀 The intake stroke draws in the fuel-air mixture, while the compression stroke increases its pressure and temperature before ignition.
• 😀 The power stroke is where combustion occurs, generating pressure that moves the piston and turns the crankshaft.
• 😀 The exhaust stroke expels combustion gases from the cylinder, completing the cycle.
• 😀 Engine operation involves systems for fuel intake, fuel supply, exhaust, lubrication, and cooling to maintain efficiency and longevity.
• 😀 Ignition timing is critical for optimal engine performance, with the spark plug firing slightly before top dead center to ensure maximum gas pressure.
• 😀 Modern engines use an engine management system that controls ignition timing, fuel injection, and more through sensors and the engine control unit (ECU).
• 😀 The fuel-air mixture in gasoline engines must be maintained at an optimal ratio (14.7:1) for balance between power and fuel economy.

Q & A

What is the basic function of an internal combustion engine (ICE)?

The basic function of an internal combustion engine is to convert the combustion energy of fuel into mechanical energy.

What is a four-stroke reciprocating engine, and how does it operate?

A four-stroke reciprocating engine operates in four strokes—intake, compression, power, and exhaust—completing one cycle over two crankshaft revolutions. The engine uses these strokes to convert the combustion of fuel into mechanical energy.

What is the role of the valve timing mechanism in an engine?

The valve timing mechanism controls the opening and closing of the inlet and exhaust valves, ensuring that the fuel-air mixture enters the cylinder and exhaust gases are expelled at the correct times.

How does a two-stroke engine differ from a four-stroke engine?

A two-stroke engine completes a full power cycle in two strokes of the piston, unlike a four-stroke engine, which requires four strokes. Two-stroke engines are less common in cars due to their reduced efficiency and higher emissions.

What happens during the compression stroke in a four-stroke engine?

During the compression stroke, the piston moves from bottom dead center to top dead center, compressing the fuel-air mixture inside the cylinder, which increases the pressure and temperature.

What is the power stroke, and what does it involve?

The power stroke occurs when the fuel-air mixture ignites, generating heat and expanding gases that force the piston from top dead center to bottom dead center, turning the crankshaft and converting thermal energy into mechanical work.

What is the significance of the exhaust stroke in a four-stroke engine?

During the exhaust stroke, the piston expels exhaust gases from the cylinder by moving from bottom dead center to top dead center, while the exhaust valves open. This completes the cycle and prepares the cylinder for the next intake.

How does engine speed relate to ignition timing?

At higher engine speeds, the ignition system must fire the spark plug earlier (advance the ignition timing) to ensure efficient combustion. At lower speeds, the ignition timing is closer to top dead center.

What is the role of the engine control unit (ECU) in modern engines?

The ECU controls the ignition timing, fuel injection, and other critical engine functions to optimize performance, efficiency, and emissions, using data from various sensors in the engine.

How does variable valve timing (VVT) improve engine performance?

Variable valve timing adjusts the timing of the valve openings and closings based on the engine’s operating conditions, improving power, fuel efficiency, and reducing emissions.