2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42
For more than a hundred years in the world, the main power unit in all wheeled vehicles has been a piston internal combustion engine. Appearing at the beginning of the 20th century and replacing the steam engine, the internal combustion engine in the 21st century remains the most profitable type of motor in terms of economy and efficiency. Let's take a closer look at how this type of internal combustion engine works, how it works, find out what other piston engines are.
Definition, ICE features
In the process of development of science and technology, the design of internal combustion engines has been constantly improved. The engines managed to prove their effectiveness. This is how piston internal combustion engines appeared and, as a subspecies, carburetor and injection engines. Diesel engines, rotary piston and gas turbine units can be distinguished.
Gasoline ICEs
The traditional piston engine is equipped with an internal combustion chamber. This is the cylinder inside the engine block. When the fuel burns, energy is released, which is then converted into mechanical movement of the crankshaft. Due to the translational movement of the pistons, which act on the system of connecting rods and the crankshaft, the flywheel is rotated. You can learn more about the design in the corresponding GOST piston internal combustion engine.
The carburetor internal combustion engine is different in that the working mixture of fuel and air is prepared in a special device - a carburetor. The mixture is injected into the cylinders by vacuum. It is then ignited by the spark plug.
Injection ICE has a more modern design. Here, instead of the traditional mechanical device, the power system has electronic nozzles. They are responsible for injecting precise amounts of fuel directly into the engine's cylinders.
Diesel ICEs
The diesel piston internal combustion engine has certain structural and fundamental differences from gasoline internal combustion engines.
If a spark from a candle is used for ignition in a gasoline unit, then a different principle works in diesel engines and there are no candles except glow. Diesel fuel enters the cylinders through injectors, mixes with air, and then the whole mixture is compressed, as a result of which it heats up to combustion temperature.
Rotor piston
Rotary piston engine essentialdiffers from traditional ICE. Gases act on special parts and elements. So, under the influence of gases, the movable rotor moves in a special chamber in the shape of a figure eight. The chamber performs the functions of pistons, timing and crankshaft. The camera is shaped like a figure of eight.
Combined units
In gas turbine internal combustion engines, thermal energy is converted into mechanical energy due to the rotation of a special rotor with special blades. This rotor drives the turbine shaft.
Special piston and combined internal combustion engines (and these are gas turbine engines and rotary engines) can be safely entered in the red book. Today, only the Japanese Mazda makes a rotary piston engine. Crysler once produced an experimental series of gas turbine internal combustion engines, but this was in the 60s and none of the automakers has returned to this issue to this day.
In the Soviet Union, gas turbine internal combustion engines were installed on tanks and landing ships, however, even there it was later decided to abandon units of this design.
ICE device
The engine is a single mechanism. It consists of a cylinder block, crank mechanism parts, timing mechanism, injection and exhaust systems.
The combustion chamber is located inside the cylinder block, where the fuel-air mixture is directly ignited, and the combustion products actuate the pistons. By means of a crankmechanism, the energy of fuel combustion is transferred to the crankshaft. The timing mechanism is necessary to ensure the timely opening and closing of the intake and exhaust valves.
Operation principle
When the engine is started, a mixture of fuel and air is injected into the cylinders through the intake valve and ignited by a spark on the spark plug generated by the ignition system. During combustion, gases are formed. When thermal expansion occurs, due to excess pressure, the piston begins to move, thereby rotating the crankshaft.
The operation of piston engines is cyclical. In the cycle of a piston internal combustion engine, there can be from two to four cycles. Cycles during the operation of the motor are repeated several hundred times in one minute. So the crankshaft can rotate continuously.
Two-stroke ICE
When the engine starts, the piston is driven by the rotation of the crankshaft. When the piston reaches bottom dead center and starts to move up, the cylinder will be supplied with a fuel-air mixture.
When moving up, the piston will begin to compress the mixture. When the piston reaches its top position, a spark will be generated. The fuel-air mixture will ignite. Expanding, the gases will push the piston down.
At this moment, the exhaust valve will open, through which the combustion products can exit the chamber. Then again reaching the bottom dead center, the piston will begin its journey to TDC. All these processes take place in one revolution of the crankshaft.
Whenthe piston will begin a new movement, the intake valve will open and a new portion of the fuel-air mixture will replace the exhaust gases. The whole process will start over. A two-stroke piston internal combustion engine makes fewer movements than a four-stroke one. Reduced friction loss but generates more heat.
The gas distribution mechanism is replaced by a piston. As the piston moves, the intake and exhaust ports in the cylinder block open and close. Compared to a four-stroke power unit, gas exchange in a two-stroke engine is a major drawback. Efficiency and power are lost when exhaust gases are released.
Despite this drawback of two-stroke piston internal combustion engines, they are used in mopeds, scooters, as outboard motors, in chainsaws.
Four-stroke internal combustion engine
Four-stroke ICE has no disadvantages of a two-stroke engine. Such motors are installed on most cars and other equipment. The intake and exhaust of exhaust gases is a separate process, and it is not combined with compression, although the piston internal combustion engine works from the ignition of the mixture. The operation of the motor is synchronized by the gas distribution mechanism - the valves open and close synchronously with the crankshaft speed. The intake of the fuel mixture is carried out only after the complete exit of the exhaust gases.
Advantages of internal combustion engines
It's worth starting with the most popular engines - in-linefour-cylinder units. Among the advantages are compactness, light weight, one cylinder head, high maintainability.
Among all types of internal combustion engines, boxer motors can also be distinguished. They are not very popular due to the more complex design. They are mainly used in racing cars. Among the advantages - excellent primary and secondary balancing, and hence the soft work. There is less stress on the crankshaft. As a result, there is little power loss. The engine has a low center of gravity and the car handles better.
Inline six-cylinder engines are perfectly balanced, and the unit itself runs very smoothly. Despite the large number of cylinders, the production cost is not very high. You can also highlight maintainability.
Disadvantages of internal combustion engines
The main drawback of reciprocating internal combustion engines is still not toxicity and noise, but poor efficiency. In an internal combustion engine, only 20% of the energy is spent on the actual mechanical work. Everything else is spent on heating and other processes. Engines also release harmful substances into the atmosphere, such as nitrogen oxides, carbon monoxide, and various aldehydes.
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