Thermal expansion of gases is used today in many devices. These are turbojet engines, diesels, and carburetors ... A thermal unit can be of two types:
- engine with external combustion;
- ICE (internal combustion engine).
Consider in detail a device of the second type.
general characteristics
On most cars today, devices are installed where the principle of an internal combustion engine is to release heat and convert it to mechanical work. This process is performed in cylinders.
The most economical options are piston and combination motors.
They can be used for a long time and are relatively small in size and weight. But the minus in them is the movement of the piston, which occurs in a reciprocating manner with the participation of the crank mechanism, which, on the one hand, makes the work more complicated, and on the other hand, is a limiter in increasing the speed. Most strongly, the latter is noticeable with large dimensions of the motor.
The creation, development and, in general, the operation of an internal combustion engine, of course, is based on the effect of thermal expansion, in which heated gases do useful work. As a result of combustion, the pressure in the cylinder jumps sharply, and the piston moves. This is the principle of force exposure, in which thermal expansion is performed, which is used in ICE and other technologies.
In order for useful
mechanical energy to be produced continuously, the combustion chamber must be replenished with an air-fuel mixture, due to which the piston drives the crankshaft, and the latter - the wheels.
Most cars today are four-stroke, and the energy in them is almost completely converted into usable.
A bit of history
The first mechanism of this type was created in 1860 by a French engineer, and two years later his compatriot proposed using a four-cycle cycle, where the operation of the internal combustion engine included the processes of absorption, compression, combustion and expansion, as well as exhaust.
In 1878, a German physicist invented the first four-stroke cycle, the efficiency of which reached 22%, which greatly exceeded the characteristics of all its predecessors.
Such a motor has become widespread in various spheres of life. Today it is used in automobiles, agricultural machinery, ships, diesel locomotives, airplanes, power plants and so on.
Advantages and disadvantages
The success is mainly due to the practical characteristics of economy, compactness and good adaptability. In addition, the engine is able to start in the most ordinary conditions, after which it quickly accelerates and reaches full load. For vehicles, such a characteristic as significant braking torque is important.
ICE (engine) is capable of operating on different types of fuel, from gasoline to boiler fuel oil.
However, these motors have a number of drawbacks, among which limited power, a lot of noise, very frequent crankshaft rotation during start-up, inability to connect to drive wheels, toxicity, reciprocating reciprocating movements stand out.
Housing
The housing is a classic design consisting of a cylinder block, their head, and in the case of a detachable lower part of the crankcase, and a fundamental frame with covers. There is also a monoblock design. Such a variety naturally implies a different repair approach.
The elements of the motor housing are the base where the parts of the timing and crank mechanism, cooling, power, lubrication and so on are attached.
Classification
The most widely used engine (internal combustion engine), in which the process takes place in the cylinders themselves. But motors can be classified according to various other attributes.
According to the working cycle, they are:
According to the method of mixture formation in an internal combustion engine, an engine is:
- with external education (gas and carburetor);
- motor with internal mixture formation (diesel).
By cooling method:
On cylinders:
- single cylinder;
- two-cylinder;
- multi-cylinder.
By their location:
- in-line (vertical or inclined);
- V-shaped.
By filling the cylinder with air:
- naturally aspirated;
- supercharged.
The frequency of rotation of the internal combustion engine (engine) is:
- slow-moving;
- increased frequency;
- high-speed.
By fuel used:
- multi-fuel;
- gas;
- diesel;
- petrol.
By compression ratio :
By appointment:
- automotive tractor;
- aviation;
- stationary;
- shipboard and so on.
Power
The power of automotive units is usually calculated in horsepower.
This term was introduced at the end of the eighteenth century by an English inventor who watched horses pulling baskets of coal from mines. Measuring the weight of the load and the height at which it is lifted, D. Watt calculated how much coal a horse can pull in a minute from a certain depth. Subsequently, this unit was named after the well-known term "horsepower". After the International System of Units (SI) was adopted in 1960, hp became an auxiliary unit, which is equal to 736 watts.