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Presentation on the physics of the internal combustion engine. Presentation - internal combustion engine

The history of the creation of the first engine internal combustion First for real
workable Internal Combustion Engine (ICE)
appeared in Germany in 1878. But the history of creation
ICE has its roots in France.
In 1860 the French inventor Ethven Lenoir
invented
the first internal combustion engine. But this unit
was imperfect, with low efficiency and could not be applied
on practice. Another Frenchman came to the rescue
inventor Beau de Rochas, who in 1862 proposed
use four strokes in this engine:
1.Inlet
2.Compression
3. Working stroke
4. Release stroke
The first four-stroke ICE car was
three-wheeled carriage by Karl Benz, built in 1885
year.
A year later (1886) Gottlieb Daimer's version appeared.
Both inventors worked independently of each other.
They merged in 1926 to form Deimler-Benz.
AG.

The principle of operation of the internal combustion engine

Modern car, most of all,
driven by an internal motor
combustion. There are many such engines.
lots of. They differ in volume
number of cylinders, power, speed
rotation, fuel used (diesel,
petrol and gas engines). But, fundamentally,
internal combustion engine device
Seems like. How does this device work and why?
called a four-stroke engine
internal combustion? About internal combustion
clear. Fuel burns inside the engine. BUT
why 4 stroke engine, what is it?
Indeed, there are two-stroke
engines. But on cars they are used
rarely. Four stroke engine
called because of the fact that his work can be
divided into four equal parts.
The piston will pass through the cylinder four times - two
up and down twice. The beat starts at
finding the piston in the extreme lower or
top point. For motorists-mechanics it is
called top dead center (TDC) and
bottom dead center (BDC).

First stroke - intake stroke

The first beat, he is the inlet,
starts at TDC (top
dead point). moving down
piston sucks into cylinder
air-fuel mixture. Work
this beat occurs when
open intake valve. By the way,
there are many engines
multiple intake valves.
Their number, size, time
being in the open
can significantly affect
engine power. There is
engines in which
depending on the pressure on the pedal
gas, forced
increase in residence time
intake valves open
condition. It's made for
increasing the number
intake fuel, which
after ignition, increases
engine power. Automobile,
in this case, maybe much
accelerate faster.

The second stroke is the compression stroke

The next stroke of the engine is
compression stroke. After the piston
bottomed out, he starts
rise up, thereby squeezing
mixture that entered the cylinder on the beat
inlet. The fuel mixture is compressed to
combustion chamber volumes. What is this
such a camera? Free space
between the top of the piston and
top of the cylinder
piston at top dead
point is called the combustion chamber.
Valves, in this stroke of the engine
closed completely. The denser they
closed, the compression occurs
better. Great importance
has, in this case, the state
piston, cylinder, piston rings.
If there are large gaps, then
good compression will not work, but
accordingly, the power of such
engine will be much lower. Degree
compression - compression, you can check
special device. By size
compression, it can be concluded that
engine wear.

Third cycle - working stroke

The third measure is a working one, it starts with
TDC. It's called a worker
not by chance. After all, it is in this
tact is an action,
forcing the car
move. In this tact to work
the ignition system comes on. Why
is this system called? Yes
because she is in charge
ignition fuel mixture, compressed
in the cylinder, in the combustion chamber.
It works very simply - a candle
system gives a spark. Justice
for the sake of it, it is worth noting that the spark
issued on the spark plug for
a few degrees before reaching
top piston. These
degrees, in a modern engine,
automatically adjusted
the brains of the car. After that
as the fuel ignites, occurs
explosion - it increases sharply in
volume, forcing the piston
move down. Valves on this beat
engine operation, as in
previous, are in a closed
condition.

The fourth measure is the release measure

Fourth cycle of work
engine, the last
high school graduation. Reaching
bottom point, after
working cycle, in the engine
starts to open
Exhaust valve. Such
valves, as well as inlet,
there may be several.
Moving up, the piston
removes through this valve
exhaust gases from
cylinder - ventilates
his. The better it works
exhaust valve,
more exhaust gases
removed from the cylinder
thereby freeing
place for a new portion
fuel-air mixture.

Varieties of the internal combustion engine

Diesel internal combustion engine

Diesel engine - piston
internal combustion engine,
flammable
atomized fuel from
contact with compressed heated
air. Diesel engines running
on diesel fuel (colloquially -
"sunshine").
In 1890, Rudolf Diesel developed the theory
"economical thermal engine",
which, due to the strong compression in
cylinders significantly improves its
efficiency. He received a patent for his
engine February 23, 1893. First
a functioning example called the "Diesel Motor" was built by Diesel by early 1897
year, and on January 28 of the same year he was successfully
tested.

The principle of operation of the injection engine

In modern injection
engines for everyone
cylinder provided
individual nozzle.
All nozzles are connected to
fuel rail, where
fuel is under
pressure that creates
electric fuel pump.
Injected quantity
fuel depends on
opening duration
nozzles. Opening moment
regulates the electronic unit
control (controller) on
based on processed
them data from various
sensors.

slide 1


Physics lesson in grade 8

slide 2

Question 1:
What physical quantity shows how much energy is released when burning 1 kg of fuel? What letter is it? Specific heat of combustion of fuel. g

slide 3

Question 2:
Determine the amount of heat released during the combustion of 200 g of gasoline. g=4.6*10 7J/kg Q=9.2*10 6J

slide 4

Question 3:
The specific heat of combustion of coal is about 2 times greater than the specific heat of combustion of peat. What does it mean. This means that the combustion of coal will require 2 times more heat.

slide 5

Internal combustion engine
All bodies have internal energy - earth, bricks, clouds and so on. However, most often it is difficult to extract it, and sometimes impossible. The most easily used for human needs is the internal energy of only some, figuratively speaking, "combustible" and "hot" bodies. These include: oil, coal, warm springs near volcanoes, and so on. Consider one of the examples of using the internal energy of such bodies.

slide 6

Slide 7

Carburetor engine.
carburetor - a device for mixing gasoline with air in the right proportions.

Slide 8

Main main parts of an internal combustion engine parts of an internal combustion engine
1 - intake air filter, 2 - carburetor, 3 - gas tank, 4 - fuel line, 5 - spray gasoline, 6 - intake valve, 7 - glow plug, 8 - combustion chamber, 9 - exhaust valve, 10 - cylinder, 11 - piston.
:
The main parts of the internal combustion engine:

Slide 9

The operation of this engine consists of several stages repeating one after another, or, as they say, cycles. There are four in total. The stroke count starts from the moment when the piston is at its highest point, and both valves are closed.

Slide 10

The first stroke is called the inlet (Fig. "a"). The intake valve opens and the descending piston draws the gasoline-air mixture into the combustion chamber. The intake valve then closes.

slide 11

The second step is compression (Fig. "b"). The piston, rising up, compresses the gasoline-air mixture.

slide 12

The third stroke is the working stroke of the piston (Fig. "c"). An electric spark flashes at the end of the candle. The gasoline-air mixture burns almost instantly and there is a heat. This leads to a strong increase in pressure and the hot gas does useful work - it pushes the piston down.

slide 13

The fourth measure is the release (rice "d"). The exhaust valve opens and the piston, moving up, pushes the gases out of the combustion chamber into exhaust pipe. Then the valve closes.

Slide 14

physical education minute

slide 15

Diesel engine.
In 1892, the German engineer R. Diesel received a patent (a document confirming the invention) for an engine, later named after him.

slide 16

Principle of operation:
Only air enters the cylinders of a Diesel engine. The piston, compressing this air, does work on it and the internal energy of the air increases so much that the fuel injected there immediately ignites spontaneously. The resulting gases push the piston back, carrying out the working stroke.

Slide 17

Work cycles:
air intake; air compression; fuel injection and combustion - piston stroke; release of exhaust gases. A significant difference: the glow plug becomes unnecessary, and its place is taken by a nozzle - a device for injecting fuel; usually these are low-quality grades of gasoline.

Slide 18

Some information about engines Engine type Engine type
Some information about engines Carburetor Diesel
History of creation First patented in 1860 by the Frenchman Lenoir; in 1878 built by German. inventor Otto and engineer Langen Invented in 1893 by German engineer Diesel
Working fluid Air, sat. gasoline vapor Air
Fuel Gasoline Fuel oil, oil
Max. chamber pressure 6 × 105 Pa 1.5 × 106 - 3.5 × 106 Pa
T at compression of the working fluid 360-400 ºС 500-700 ºС
T of fuel combustion products 1800 ºС 1900 ºС
Efficiency: for serial machines for the best samples 20-25% 35% 30-38% 45%
Application In cars of relatively small power In heavier machines of high power (tractors, freight tractors, diesel locomotives).

Slide 19

Slide 20

Name the main parts of the engine:

slide 21

1. What are the main cycles of the internal combustion engine. 2. In what cycles are the valves closed? 3. In what cycles is valve 1 open? 4. In what cycles is valve 2 open? 5. What is the difference between an internal combustion engine and a diesel engine?

slide 22

Dead spots - extreme positions of the piston in the cylinder
Piston stroke - the distance traveled by the piston from one dead center to another
Four-stroke engine - one working cycle occurs in four piston strokes (4 cycles).

slide 23

Fill in the table
Bar name Piston movement 1 valve 2 valve What happens
Inlet
Compression
working stroke
release
down
up
down
up
open
open
closed
closed
closed
closed
closed
closed
Suction combustible mixture
Compression of the combustible mixture and ignition
The gases push the piston
Exhaust gas emission

slide 24

1. Type heat engine, in which steam rotates the engine shaft without the help of a piston, connecting rod and crankshaft. 2. Designation of specific heat of fusion. 3. One of the parts of the internal combustion engine. 4. Cycle cycle of an internal combustion engine. 5. The transition of a substance from a liquid to a solid state. 6. Vaporization occurring from the surface of the liquid.


INTERNAL COMBUSTION ENGINE DEVICE The engine consists of a cylinder in which piston 3 moves, connected by means of connecting rod 4 to crankshaft 5. In the upper part of the cylinder there are two valves 1 and 2, which automatically open and close at the right time when the engine is running. A combustible mixture enters the cylinder through valve 1, which is ignited with the help of candle 6, and exhaust gases are released through valve 2. In the cylinder of such an engine, a combustion of a combustible mixture consisting of gasoline vapors and air periodically occurs. The temperature of the gaseous products of combustion reaches degrees Celsius.


OPERATION OF THE INTERNAL COMBUSTION ENGINE I STROKE One stroke of the piston, or one stroke of the engine, is completed in half a revolution of the crankshaft. When the engine shaft rotates at the beginning of the first stroke, the piston moves down. The volume above the piston increases. As a result, a vacuum is created in the cylinder. At this time, valve 1 opens and a combustible mixture enters the cylinder. By the end of the first stroke, the cylinder is filled with a combustible mixture, and valve 1 closes.


OPERATION OF THE INTERNAL COMBUSTION ENGINE STROKE II With further rotation of the shaft, the piston moves up (second stroke) and compresses the combustible mixture. At the end of the second stroke, when the piston reaches its extreme upper position, the compressed combustible mixture ignites (from an electric spark) and quickly burns out.


WORK OF THE INTERNAL COMBUSTION ENGINE III STROKE Under the influence of expanding heated gases (third stroke), the engine performs work, therefore this stroke is called the working stroke. The movement of the piston is transmitted to the connecting rod, and through it to the crankshaft with a flywheel. Having received a strong push, the flywheel then continues to rotate by inertia and moves the piston attached to it on subsequent cycles. The second and third cycles occur with closed valves.


OPERATION OF THE INTERNAL COMBUSTION ENGINE STROKE IV At the end of the third stroke, valve 2 opens, and through it the combustion products exit the cylinder into the atmosphere. The release of combustion products continues during the fourth stroke, when the piston moves up. At the end of the fourth stroke, valve 2 closes.

creation..

History of creation

Etienne Lenoir (1822-1900)

Stages of ICE development:

1860 Étienne Lenoir invents the first light gas engine

1862 Alphonse Beau De Rochas proposed the idea of ​​a four-stroke engine. However, he failed to implement his idea.

1876 ​​Nikolaus August Otto creates the Roche four-stroke engine.

1883 Daimler proposed the design of an engine that could run on both gas and gasoline

Karl Benz invented the self-propelled tricycle based on Daimler technology.

By 1920, internal combustion engines become leading. crews on steam and electric traction have become a rarity.

August Otto (1832-1891)

Karl Benz

History of creation

Tricycle, invented by Karl Benz

Operating principle

Four stroke engine

Duty cycle of a four-stroke carburetor engine internal combustion takes place in 4 strokes of the piston (stroke), i.e., in 2 revolutions of the crankshaft.

There are 4 cycles:

1 stroke - intake (the combustible mixture from the carburetor enters the cylinder)

2 stroke - compression (the valves are closed and the mixture is compressed, at the end of the compression the mixture is ignited by an electric spark and the fuel is burned)

3 stroke - working stroke (there is a conversion of the heat received from the combustion of fuel into mechanical work)

4 stroke - release (exhaust gases are displaced by the piston)

Operating principle

Two stroke engine

There is also two stroke engine internal combustion. The working cycle of a two-stroke carburetor internal combustion engine is carried out in two strokes of the piston or in one revolution of the crankshaft.

1 measure 2 measure

Combustion

In practice, the power of a two-stroke carburetor internal combustion engine often not only does not exceed the power of a four-stroke, but is even lower. This is due to the fact that a significant part of the stroke (20-35%) the piston makes with open valves

Engine efficiency

The efficiency of an internal combustion engine is low and is approximately 25% - 40%. The maximum effective efficiency of the most advanced internal combustion engines is about 44%. Therefore, many scientists are trying to increase the efficiency, as well as the very power of the engine.

Ways to increase engine power:

Use of multi-cylinder engines

Use of special fuel (correct mixture ratio and type of mixture)

Replacement of engine parts ( correct sizes constituent parts, depending on the type of engine)

Elimination of part of the heat loss by transferring the place of fuel combustion and heating of the working fluid inside the cylinder

Engine efficiency

Compression ratio

One of the most important characteristics of an engine is its compression ratio, which is determined by the following:

eV2V1

where V2 and V1 are the volumes at the beginning and at the end of compression. With an increase in the compression ratio, the initial temperature of the combustible mixture at the end of the compression stroke increases, which contributes to its more complete combustion.

Varieties of internal combustion engines

Internal Combustion Engines

Main engine components

The structure of a bright representative of the internal combustion engine - a carburetor engine

Engine frame (crankcase, cylinder heads, crankshaft bearing caps, oil pan)

movement mechanism(pistons, connecting rods, crankshaft, flywheel)

Gas distribution mechanism(camshaft, pushrods, rods, rocker arms)

Lubrication system (oil, coarse filter, sump)

liquid (radiator, liquid, etc.)

Cooling system

air (blowing with air currents)

Power system (fuel tank, fuel filter, carburetor, pumps)

Main engine components

Ignition system(current source - generator and battery, breaker + capacitor)

Starting system (electric starter, current source - battery, remote controls)

Intake and exhaust system(pipelines, air filter, muffler)

Engine carburetor

slide 2

An internal combustion engine (ICE) is a type of engine heat engine, in which the chemical energy of the fuel (usually liquid or gaseous hydrocarbon fuels) burning in the working area is converted into mechanical work. Despite the fact that internal combustion engines are a very imperfect type of heat engines (low efficiency, loud noise, toxic emissions, less resource), due to their autonomy (the necessary fuel contains much more energy than the best electric batteries), internal combustion engines are very widespread, for example, in transport.

slide 3

ICE types

Rotary piston

slide 4

Petrol

The mixture of fuel with air is prepared in the carburetor and then in the intake manifold, or in the intake manifold using spray nozzles (mechanical or electric), or directly in the cylinder using spray nozzles, then the mixture is fed into the cylinder, compressed, and then ignited with a spark slipping between the electrodes of the candle.

slide 5

Diesel

Special diesel fuel is injected into the cylinder at high pressure. The ignition of the mixture occurs under the action of high pressure and, as a result, the temperature in the chamber.

slide 6

Gas

an engine that burns as fuel hydrocarbons that are in a gaseous state under normal conditions: mixtures of liquefied gases - stored in a cylinder under saturated vapor pressure (up to 16 atm). The liquid phase evaporated in the evaporator or the vapor phase of the mixture gradually loses pressure in the gas reducer to close to atmospheric pressure, and is sucked by the engine into the intake manifold through an air-gas mixer or injected into the intake manifold by means of electric injectors. Ignition is carried out with the help of a spark that jumps between the electrodes of the candle. compressed natural gases - stored in a cylinder under a pressure of 150-200 atm. The design of power systems is similar to liquefied gas power systems, the difference is the absence of an evaporator. generator gas - a gas obtained by converting a solid fuel into a gaseous one. As solid fuels are used: coal peat wood

Slide 7

Rotary piston

Due to the rotation in the combustion chamber of the multifaceted rotor, volumes are dynamically formed in which the normal cycle of the internal combustion engine takes place. Scheme

Slide 8

Four-stroke internal combustion engine

Scheme of operation of a four-stroke engine cylinder, Otto cycle. inlet2. compression3. duty cycle 4. release

Slide 9

rotary internal combustion engine

Wankel engine cycle: intake (blue), compression (green), power stroke (red), exhaust (yellow) A rotor with a gear wheel, as it were, rolls around the gear. At the same time, its edges slide over the surface of the cylinder and cut off the variable volumes of the chambers in the cylinder.

Slide 10

Two-stroke internal combustion engine

Duplex cycle. in a two-stroke cycle, work strokes occur twice as often. Fuel Injection Compression Ignition Exhaust

slide 11

Additional units required for internal combustion engines

The disadvantage of internal combustion engines is that it only produces high power over a narrow rev range. Therefore, the essential attributes of an internal combustion engine are the transmission and the starter. Only in some cases (for example, in airplanes) can a complex transmission be dispensed with. Also ICE is needed fuel system(for supplying the fuel mixture) and exhaust system(for exhaust gases).

slide 12

Starting an internal combustion engine

Electric starter The most convenient way. When starting, the engine is spun by an electric motor (in the figure - a rotation diagram of a simple electric motor), powered by battery(After starting, the battery is recharged by the generator driven by the main engine). But it has one significant drawback: in order to crank the crankshaft of a cold engine, especially in winter, it needs a large starting current.