How does a four stroke diesel engine work?

A four-stroke gasoline engine mixes air with gasoline in a certain ratio to form a good mix.

Car engines.

The gas is sucked into the cylinder during the suction stroke, and the mixture is compressed and ignited to produce heat energy, and the high-temperature and high-pressure gas acts on the top of the piston to promote the piston to reciprocate linear motion, and outputs mechanical energy through the connecting rod and crankshaft flywheel mechanism. A four-stroke gasoline engine completes a working cycle in the intake stroke, compression stroke, power stroke and exhaust stroke.

1. Inlet air (piston down).

2. Compressed air + sprayed diesel (piston up).

3. Do work (piston down).

4. Exhaust gas (piston up).

Engine working principle: It is divided into two-stroke engine and four-stroke engine working principle.

<> "How a four-stroke gasoline engine works.

The interpretation of stroke is the stroke, the process of getting from one position to another; The vast majority of gasoline engines are four-stroke engines, and a four-stroke engine means that the sum of the processes from top dead center to bottom dead center and bottom dead center to top dead center is four times. So how does a four-stroke gasoline engine work?

1.The working principle of the four-stroke gasoline engine is relatively simple: after four strokes of air intake, compression, work and exhaust, a working cycle is completed, and in this process, the piston reciprocates up and down and moves four strokes, and the corresponding crankshaft rotates for two weeks.

2.The first is the intake stroke: the piston runs from top to point and down to point. The intake valve opens and the exhaust valve closes. Due to the difference in air pressure, the mixed combustible gas is sucked in.

3.Again, there is the compression stroke: the piston runs from bottom to point, and the intake and exhaust valves are closed. The flammable gas mixture is compressed and almost reaches the ignition point.

4.Later came the power stroke: the intake and exhaust valves were still closed. When the piston is about to run to the point for the second time, the spark plug ignites the combustible gas mixture. The flammable gas mixture expands, moving the piston from top to bottom.

5.Finally, there is the exhaust stroke: the piston runs from the bottom to the point, the intake valve closes, and the exhaust valve opens.

That's all there is to know about how a four-stroke gasoline engine works.

(1) The main difference in structure is: the ignition system of the gasoline engine, while the diesel engine does not have an ignition system, and there are also differences in the fuel supply system.

2) Differences in working principle:

The mixture of gasoline engines is formed on the outside of the cylinder (except for modern direct injection technology), while the mixture of diesel engines is formed on the inside of the cylinder. - The situation has changed with the development of modern automotive technology.

At the end of the compression stroke, the gasoline engine is forced to ignite by spark plugs, while the diesel engine is self-combusted.

It also varies within the individual duty cycles.

The gasoline engine mixes air and gasoline in a certain proportion into a good mixture, which is sucked into the cylinder during the intake stroke. The mixture is compressed and ignited to produce heat energy. The high-temperature and high-pressure gas acts on the top of the piston, pushing the piston to reciprocate in a straight line, and outputs mechanical energy outward through the connecting rod and crankshaft flywheel mechanism.

The four-stroke gasoline engine completes a working cycle in the intake stroke, compression stroke, power stroke and exhaust stroke.

Driven by the crankshaft, the piston moves from top dead center to bottom dead center. At this point, the intake valve opens, the exhaust valve closes, and the crankshaft rotates 180°. During the piston movement, the cylinder volume gradually increases, the gas pressure in the cylinder gradually decreases from PR to PA, and a certain degree of vacuum is formed in the cylinder.

The mixture of air and gasoline is sucked into the cylinder through the intake valve and further mixed in the cylinder to form a combustible mixture. Due to the resistance of the intake system, the gas pressure in the cylinder at the end of the intake is 0p lower than the atmospheric pressure, that is, Pa = (, the combustible mixture entering the cylinder rises to 340 400K due to the heating of the intake pipe, cylinder wall, piston top, valve, combustion chamber wall and other high-temperature parts, as well as the mixing with the residual exhaust gas.

During the compression stroke, the intake and exhaust valves close at the same time. The piston moves from bottom dead center to top dead center, and the crankshaft rotates 180°. When the piston moves up, the working volume gradually decreases, and the pressure and temperature of the mixture in the cylinder continue to increase after compression.

When the end point of compression is reached, the pressure PC can reach 800 2000kPa, the temperature can reach 600 750K, and the compression stroke is curve A C on the dynamometer diagram. When the piston is close to the top dead center, the spark plug ignites the combustible mixture, and the combustion of the mixture releases a large amount of heat energy, which makes the pressure and temperature of the gas in the cylinder rise rapidly. The maximum combustion pressure pz is 3000 6 000kpa, the temperature tz is 2200 2800k, and the high temperature and high pressure gas pushes the piston to move from the top dead center to the bottom dead center, and outputs mechanical energy through the crank connecting rod mechanism.

As the piston moves downwards, the cylinder volume increases and the gas pressure and temperature gradually decrease. When point B is reached, its pressure drops to 300 500kpa, the temperature drops to 1200 1500k, and during the power stroke, the intake and exhaust valves are closed, and the crankshaft rotates 180°.

During the exhaust stroke, the exhaust valve opens, the intake valve remains closed, the piston moves from bottom dead center to top dead center, and the crankshaft rotates 180°. When the exhaust valve is opened, the combustion exhaust gases are discharged to the outside of the cylinder under the pressure difference between the inside and outside of the cylinder on the one hand, and to the outside of the cylinder through the displacement of the piston on the other. Due to the drag of the exhaust system, the pressure at the exhaust terminal r is slightly higher than the atmospheric pressure, i.e., pr=(.

The temperature of the exhaust end TR = 900 1100K, when the piston moves to the top dead center, there is still a certain amount of exhaust gas in the combustion chamber that cannot be discharged. This part of the exhaust gas is called residual exhaust gas.

1. Suction stroke, piston descends, and inhale the mixture. 2. Compression stroke, piston rise, compression mixture. 3. Do the power stroke, ignite the fuel, and press the piston down to do the work.

4. Exhaust stroke, piston rises, and exhaust gas is discharged. There are four strokes of air intake, compression, combustion work and exhaust to complete a working cycle.

The principle is that the gasoline is first collected, then compressed, pushed, and then generated to exhaust the power.

The working principle of the four-stroke gasoline engine: suction stroke: the piston descends, and the mixture is sucked in; Compression stroke: piston rises, compresses the mixture; Power stroke: ignition burns fuel, and the piston presses down to do work; 4. Exhaust stroke, piston rises, and exhaust gas is discharged.

In order to make the engine generate power, fuel and air must be supplied to the cylinder first, and then it is burned to produce heat energy after compression, and the gas is used as the working medium and the crankshaft is rotated by pushing the piston and connecting rod, so that the heat energy is converted into mechanical energy, and finally the exhaust gas after combustion is discharged from the cylinder. At this point, the engine completes a duty cycle. This cycle repeats itself and the engine generates continuous power.

The working principle of a four-stroke diesel engine is:

The work of the diesel engine is done by the four processes of air intake, compression, combustion expansion and exhaust, which constitute a working cycle. The piston goes through four processes to complete the sock bucket and one working cycle of the diesel engine is called a four-stroke diesel engine.

Intake stroke: the intake valve is opened, the exhaust valve is closed, the piston is driven by the crankshaft and connecting rod, moves from the top dead center to the bottom dead center, sucks fresh air into the cylinder, the piston reaches the bottom dead center, and the intake stroke ends.

Compression stroke: the intake and exhaust valves are closed, the piston is driven by the crankshaft and connecting rod, moves from the bottom dead center to the top dead center, the air sucked into the cylinder is compressed into high temperature and high pressure gas, and when the piston reaches the top dead center, the compression stroke ends.

Power stroke: After the compression stroke is over, (the intake and exhaust valves are still closed) the fuel injector will inject fuel into the cylinder, under the action of high temperature and high pressure gas, the fuel is compression-ignited, and a huge amount of energy is generated in the cylinder, which pushes the piston to move from the top dead center to the bottom dead center, the crankshaft flywheel group stores and outputs energy, and when the piston reaches the bottom dead center, the power stroke ends.

Exhaust stroke: the intake valve is closed, the exhaust valve is opened, the piston is driven by the crankshaft and connecting rod, and moves from the bottom dead center to the top dead center, and the exhaust gas after combustion in the cylinder is discharged, and when the piston reaches the top dead center, the exhaust stroke ends. In the four strokes of air intake, compression, work and exhaust, only the power stroke produces energy, and the other three strokes are completed by the inertia of the crankshaft and flywheel.

The working principle of the four-stroke diesel engine The working principle of the diesel engine is completed by the four processes of air intake, compression, combustion expansion and exhaust, these four processes constitute a working cycle, and the piston goes through four processes to complete a working cycle The diesel engine is called a four-stroke diesel engine.

The four-stroke engine belongs to the reciprocating piston internal combustion engine, which is divided into three categories: gasoline engine, diesel engine and gaseous fuel engine according to the different types of fuel used. A piston internal combustion engine fueled by gasoline or diesel is called a gasoline engine or a diesel engine, respectively. Piston internal combustion engines that run on natural gas, liquefied petroleum gas, and other gaseous fuels are called gaseous fuel engines.

Gasoline and diesel are both petroleum products that are the traditional fuels for automobile engines. Non-petroleum fuels are referred to as alternative fuels. Engines that burn alternative fuels are called alternative fuel engines, such as ethanol engines, hydrogen engines, methanol engines, etc.

1. Each working cycle of the engine is composed of intake stroke, compression stroke, power stroke and exhaust stroke, while the four-stroke engine needs to complete a working cycle, and the piston needs to make 4 strokes in the cylinder (that is, the crankshaft rotates 2 revolutions);

2. The working fluid entering the cylinder is pure air. Due to the less resistance of the diesel engine intake system, the pressure at the end of the intake air is pa=(, which is higher than that of the gasoline engine. The intake terminal temperature ta = 300 340K, which is lower than that of gasoline engine;

3. Since the compressed working fluid is pure air, the compression ratio of the diesel engine is higher than that of the gasoline engine (generally =16 22). The pressure at the end of compression is 3000 5000kpa, and the temperature at the end of compression is 750 1000k, which greatly exceeds the autoignition temperature of diesel (about 520k);

4. When the compression stroke is nearing the end, under the action of the high-pressure oil pump, the diesel fuel is sprayed into the cylinder combustion chamber through the injector at a high pressure of about 10MPa, and it is immediately ignited and burned after being mixed with air in a very short time. The pressure of the gas in the cylinder rises rapidly to a maximum of 5,000 9,000 kPa and a maximum temperature of 1,800 2,000 kPa. Because the diesel engine ignites and burns by compression, the diesel engine is called a compression-ignition engine;

5. The exhaust of the diesel engine is basically the same as that of the gasoline engine, but the exhaust temperature is lower than that of the gasoline engine. General TR = 700 900K. For single-cylinder engines, their rotational speed is uneven, the engine works unsmoothly, and the vibration is large.

This is because only one of the four strokes is for work, and the other three are for the work that consumes the power of the work to prepare for the work. In order to solve this problem, the flywheel must have a large enough moment of inertia, which in turn will lead to an increase in the overall engine mass and good buried size. The use of multi-cylinder engines can compensate for the above shortcomings.

Modern automobiles mostly use four-, six- and eight-cylinder engines.

How does a diesel engine work:

The working process of the diesel engine is the same as that of the gasoline engine, and each working cycle also goes through four strokes: air intake, compression, work and exhaust. The diesel engine inhales pure air in the intake stroke. Near the end of the compression stroke, the diesel fuel is injected into the cylinder by the fuel injection pump, and is mixed with the compressed high-temperature air in a very short time to form a combustible mixture.

Due to the high compression ratio of the diesel engine, the air pressure and temperature in the cylinder are very high at the end of compression, which greatly exceeds the spontaneous ignition temperature of the diesel. Therefore, after the diesel fuel is injected into the cylinder, it mixes with the air in a very short time and immediately ignites and burns on its own.

Similarly, each duty cycle consists of an intake stroke, a compression stroke, a power stroke and an exhaust stroke. Compared with gasoline, diesel has a low autoignition temperature and high viscosity that is not easy to evaporate, so the diesel engine adopts compression ignition ignition at the end of compression (compression ignition grinding ignition), while the gasoline engine is a spark plug.

Ignite. The engine is the chemical energy.

Converted into mechanical energy.

The transformation process of the machine is actually the process of the work cycle, simply put, the Heng Chong bucket generates kinetic energy by burning the fuel in the cylinder, and drives the reciprocating motion of the piston in the engine cylinder, thereby driving the connecting rod connected to the piston and the crank connected with the connecting rod around the crankshaft.

The center moves in a reciprocating circular motion.

And the output of power.

1. Body: It is the assembly base of each part of the engine. It includes the cylinder head, cylinder block, lower crankcase (oil pan). The cylinder head and the inner wall of the cylinder block together form part of the combustion chamber. Many parts of the body are part of other systems.

2. Crank connecting rod mechanism: It is a mechanism used by the engine to generate and transmit power, through which the linear reciprocating motion of the piston is transformed into the rotary motion of the crankshaft and output power. It includes pistons, piston pins, connecting rods, crankshafts with flywheels, and cylinder blocks, among others.

4. Fuel supply system: The fuel supply system of gasoline judgment machine includes gasoline tank, gasoline pump, gasoline filter and air filter.

Carburetors, intake pipes, exhaust pipes, exhaust mufflers, etc. Its function is to mix gasoline and air into a suitable combustible mixture and supply it to the cylinder for combustion, and exhaust the exhaust gases generated by combustion out of the engine.

5. Cooling system: mainly including water pump, radiator, phoenix fan, water distribution pipe, cylinder block and water jacket in the cylinder head. Its function is to dissipate the heat of high-heat parts into the atmosphere to ensure the normal operation of the engine.

6. Lubrication system: including oil pump, pressure limiting valve, lubricating oil channel, filter collector, oil filter and oil radiator, etc. Its function is to supply lubricating oil to the friction parts to reduce the friction resistance between them, reduce the wear of the parts, and partially cool the friction parts and clean the friction surface.