Ask yourself this: Have you ever considered how intriguing a car actually is? You fill the device with liquid, sit in a chair, and move your hands and feet in order to move around the room more quickly. No one would have imagined 200 years ago that 4-wheeled metal carriages would be enclosed and capable of speeds more than 27 metres per second. However, it has occurred, and things will continue to improve from here on out. Here, we’ll investigate the engine, the part of the vehicle responsible for its rapid acceleration. We’re going to dissect all of its complex parts and see how they work. So let’s get started with this post and learn about how an automobile engine functions.
How a Car Engine Works: The 3 Main Parts
In broad terms, the engine can be segregated into three key parts, the head, the block and the oil sump.
1.The cylinder headis the channel through which the fuel enters the engine chamber and exhaust gases exit. Its key components are the camshafts, valves and spark plug.
2.The cylinder blockis where all the combustion action takes place. The key components here are the combustion chamber, piston, and the crankshaft.
3.The oil sumpconstitutes the lowermost part of the engine. Its key components are the oil pan and the oil filter.
How a Car Engine Works: The Fundamental Workflow
Today’s automotive engines are 4-stroke, meaning they generate useful power over the course of four piston strokes. The piston moves from its lowest point (Bottom Dead Centre) to its highest point (Top Dead Centre) and back again during each stroke. Intake, Compression, Power, and Exhaust are the four strokes. To better understand the power cycle, we can look at a flowchart that outlines the many steps involved:
How a Car Engine Works: The Processes Inside the Engine Head
The intake manifold is the starting point for the combustion process in an internal combustion engine. The air and fuel combination enters the combustion chamber via the intake manifold. From the throttle body, air is drawn into the manifold. Contrarily, the gasoline is pumped into the manifold’s tailpiece by a nozzle known as the fuel injector.
The fuel release valve, or tap, is our next stop. The valve, in its most basic form, is the mechanism that keeps the combustion chamber sealed and opens the gate when fuel is introduced or gases are released. Valve opening and closing corresponds to the type of stroke taking place. A rod called a camshaft acts as an actuator, controlling when valves open and close.
Cams are projections from the camshaft’s cylinder that form drops. The valve is allowed to open when the port is pushed downward by the cam as it rotates against it. When the pointed end changes to a rounded one, the valve is closed by the springs that hold it in its previous position. Belts and pulleys connect the camshaft’s rotation to the crankshaft’s. There is a manual adjustment for the timing of the rotation, which is extremely precise and delicate.
How a Car Engine Works: Processes Inside the Engine Block
Let’s go on to the meat of the matter at hand, the combustion process. The head has a combustion chamber where the actual burning occurs. The piston plays a vital role in this setup. The piston’s motion initiates the rotational force applied to the wheels. At least four complete strokes, or travels from one end of the cylinder to the other, are required to create useful power from the piston. Okay, let’s break down these 4 strokes:
The 4 Strokes of the Engine:
1.Intake Stroke:The combustion starts with the piston at the top dead centre or TDC position. The piston now starts to move down. Just before the piston begins its downward motion, the intake valve opens up. As the piston moves down, it sucks in the fresh air-fuel mixture from the manifold. As the piston reaches bottom dead centre or BDC, the chamber fills up with air-fuel mixture.
2.Compression Stroke:Once the piston has reached BDC, the compression stroke begins. Just before the piston reaches the lowermost position, the intake valve closes. Now the piston moves upwards. As it moves up, it compresses the air-fuel mixture as it has no place to escape with the closed valves.
3.Power Stroke:Just before the piston reaches the topmost position in the compression stroke, the spark plug mounted on the cylinder head lets off a very tiny spark. When this spark comes into contact with the compressed air-fuel mixture, it ignites the mixture. Once ignited, the flame rapidly expands. Since the valves are still closed, the flame has no place to escape and pushes the piston downwards. This is the power stroke where usable power is generated by the motion of the piston.
*Note–Diesel Engines don’t have spark plugs. Instead, the fuel injector sits in that position. On diesel engines, the combustion mechanism is slightly different. Only hot air is sent to the combustion chamber during the intake stroke. This air is then compressed which causes it to heat up even more. During the power stroke, the injector sprays the fuel which on coming into contact with the hot air catches fire and starts the combustion. The remaining cycle is the same as a petrol engine.
4.Exhaust Stroke: Last comes the exhaust stroke. The piston with the momentum gained from the previous stroke starts to move back upwards. As it begins to move, the exhaust valve opens up. The leftover gases from the combustion process are pushed out. With this one 4-stroke cycle is completed. After this, the piston again moves from TDC to BDC and the cycle restarts.
You may be asking where the force comes from that causes the piston to descend when you turn the key from the off position. The engine’s starter motor is responsible for this. When you flip the key in the ignition, the starter motor provides the initial thrust that pushes the piston down, kicking off the engine’s combustion process. The force required to move the piston is then provided by the momentum built up in each power cycle.
A crankshaft is a rotating shaft that is joined to the piston through a connecting rod. Crankpins are offset projections on the connecting rod that the piston rides on. The piston’s up and down motion is therefore transformed into a spinning motion. The crankshaft rotates, and that motion travels through a number of components before it reaches the wheel. In a subsequent piece, we’ll examine the transmission of energy to the wheels in greater depth.
How a Car Engine Works: The Oil Sump
When looking at the engine from the bottom up, the Oil Sump will be the lowest point. The oil sump receives the lubricating oil and distributes it to the various engine elements. Both the oil pan and the oil pump are housed in the oil sump. The oil pan serves as a storage tank for all of the fluid. The oil pump, which is responsible for drawing oil from the oil pan and pumping it into the lubrication passageway, is completely submerged in the oil pan.
A little screen at the oil pump’s inlet keeps big particles from getting through. Once the oil has been drawn into the pump, it is sent to a main oil filter, where it is further cleaned of larger dirt and metal fragments. In order to lubricate the moving elements of the engine, this oil is sent into the lubricant channel. This oil drains through a different pipe back to the sump, where the cycle begins again.
Piston movement is made easier by spraying oil directly into the combustion chamber. However, the combustion will not work properly if oil and gasoline are combined. In such case, how does one go about greasing the sleeve that surrounds the piston? A series of rings wrap around the piston’s axis. As the piston reaches bottom dead centre (BDC) in a 4-stroke cycle, oil is sprayed onto the chamber walls. When the piston begins to descend, oil spray is halted and extra oil is scraped off the walls by the rings. This ensures that the oil and fuel never combine.
In conclusion, this is how an automobile engine operates. We will pick up where we left off at the crankshaft in the next section. There, we’ll be able to observe the engine’s power transmission to the many parts it contacts. Please let us know if you have any questions or comments about this article; we love hearing from our readers!