Cars are made up of complex parts and technologies, but understanding them and knowing how they work can make them more approachable. Learn about the four-stroke cycle of an engine, how it drives, how it brakes, and how it transmits power and keeps us moving safely.
The biggest difference between plants and animals is their ability to move around on their own, but humans aren’t the best at it. Nevertheless, one of the main reasons we’re able to move around the planet is thanks to the automobile. When the automobile first appeared, it was called many different names, including Automation, Oleo Locomotive, Motor Rig, and Electrobat, due to its self-moving nature. Then, in 1876, the name Automobile, which means “moving by itself,” was introduced in France. According to the Korean Industrial Standards (KS), an automobile is defined as a vehicle that is equipped with a prime mover and steering device and can be driven on the ground with a passenger. Automobiles are classified into diesel, electric, LPG, and gasoline cars depending on the source of power, but they basically share the same driving principle. Let’s take a look at the basic structure and principles of the automobile.
The basic structure of the automobile was established by Frenchman Panhard Levassor in 1891. Since then, many rear-wheel drive vehicles have adopted this design. A car is made up of about 30,000 parts, which can be divided into two main parts: the body & frame and the chassis. The chassis is the part that makes the car function, which can be divided into the engine, powertrain, and wheels.
First of all, the engine is the heart of any machine. When you get in the driver’s seat and start the car, electricity is supplied from the battery to turn the flywheel of the starter motor, which starts to move the crankshaft, pistons, and valves together. The most important power generating engine in a car is a piston engine. A piston engine is an internal combustion engine that uses the expansion force of gases that have been changed to high pressure and high temperature by injecting and burning fuel and oxygen inside the cylinder to move the piston. At this time, the linear motion of the piston moving up and down is converted into rotational motion of the crankshaft through the connecting rod to rotate the wheels.
A typical automobile engine operates in a four-stroke cycle. The four-stroke cycle consists of an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, which causes the crankshaft to rotate twice. Most gasoline engines operate with this four-stroke cycle, but unlike gasoline engines, where the intake stroke is followed by the compression stroke, diesel engines first compress air to create a high temperature and pressure inside the cylinder, and then inject diesel fuel with a low ignition point to burn without a spark plug.
After using the power generated by the four-stroke cycle, the exhaust from the engine passes through a three-stage catalytic converter to remove harmful gases before being exhausted into the atmosphere through a muffler. The ternary catalytic converter removes pollutants such as carbon monoxide, hydrocarbons, and nitric oxide from the exhaust that pollute the environment. The heat generated by the engine must be dissipated through the coolant to the radiator, because if it is not cooled, it can cause an overheating phenomenon that damages or melts parts around the engine due to high heat.
The rotation of the crankshaft generated by the four-stroke process of the engine described above is transmitted to the transmission through the flywheel. If the driver is depressing the clutch or the gear is in neutral, no rotational force is transmitted to the wheels. When the clutch pedal is slowly released after shifting from neutral to first, the clutch disk squeezes against the flywheel, transmitting power. This power is sent to the wheels through the transmission, which adjusts the engine power to the situation.
Depending on which wheels the power is sent to, cars are categorized into front-engine front drive (FF), front-engine rear drive (FR), and 4-wheel drive (4WD). FF cars are driven by power from the front engine to the front wheels, while FR cars are driven by power from the front engine to the rear wheels. A 4WD car drives by sending power to all four wheels.
The main purpose of a car is to transfer power from the engine to the wheels to make the car move. But just as important are the brakes, which are the brakes that slow or stop the car. There are two types of brakes: foot brakes, which are operated with your feet, and hand brakes, which are operated with your hands. The hand brake is mainly used when parking, and it stops the wheels by pulling on a cable connected to the rear wheel, which pushes the lining of the rear wheel against the brake drum. The foot brake works by using the pressure of the brake fluid, and when you press the brake pedal, the hydraulic pressure is sent to all the wheels simultaneously to stop them.
A car is a complex of many technologies. However, instead of thinking of these technologies as too difficult and incomprehensible, it’s possible to understand the principles behind them with a little study. As the saying goes, “Learn the principles of anything first,” and I believe that if people can understand the principles of cars instead of just seeing them as high-tech, they will be one step closer to driving them.
