What is the intake stroke of a gasoline engine?

At the start of the engine's intake stroke, the piston is at the top dead center and the combustion chamber is filled with exhaust gases from the previous working cycle. When the piston moves from the top dead center to the bottom dead center, the volume of the combustion chamber becomes larger, forming a vacuum, and at the same time, the cam is driven to rotate through the gear, so that the protruding part of the cam is pushed open to the intake valve, and the fuel is mixed with air through the carburetor to form a combustible mixture into the cylinder. Hope!

The engine bai is forcibly divided into several categories, 1, by stroke, two-stroke and four-stroke du. zhi

Two-strokes have two strokes, an aspirated power stroke and an exhaust compression stroke.

A mixture of fuel and lubricating oil is used to ignite a spark plug at the top of the piston, after which the piston works downwards while the gas mixture to be compressed next time is sucked in. The piston then goes up to compress the gas mixture and then ignites. Looping back and forth.

Four-strokes have four strokes.

Inhale, compress, do work, exhaust.

Suction stroke, piston downward movement, generating negative pressure, engine intake valve open, inhaling air (diesel engine) or oil-gas mixture (gasoline engine), compression stroke, piston upward movement, generating high pressure, intake valve and exhaust valve are closed, compressing the gas in the cylinder, doing power stroke, after the piston reaches the top, ignition (gasoline engine) or fuel injection (diesel engine) makes the gas in the cylinder deflagrate, generate power, make the piston move downward.

In the exhaust stroke, the piston moves upwards to generate pressure, open the exhaust valve, and expel the burned gas.

The piston generates the power to move up and down through the connecting rod and crankshaft, and changes the up and down motion into rotary motion, which passes through the gears and tires and transmits to the ground.

2. According to the fuel content, the gasoline engine needs to vaporize the gasoline when the air is intake, mix it in the air to achieve a certain air-fuel ratio, and then use a spark plug to generate an arc to ignite the gas after compression.

Diesel engine, compress air to the deflagration point of diesel fuel in the compression stroke, and directly compress ignition.

The same is true for other oils.

The electric motor rotates directly through electromagnetic induction, switching the magnetic field on the stator or rotor. The motor that switches the magnetic field on the rotor is a brushed motor, and the motor that switches the magnetic field on the stator is a brushless motor. The brush motor is automatically switched by the rotation of the rotor, so the structure is very simple, the cost is low, the torque is large, stable and reliable.

The disadvantage is that the rotational speed is low and the rotational speed is uncontrollable.

Because of the non-contact structure, the speed of the brushless motor is controlled by an external inverter, and the inverter changes the phase of the magnetic field to control the speed and promote the rotation of the motor. The contactless structure ensures low friction and can be used at very high speeds.

3. Miscellaneous. The steam engine, a two-stroke, uses boiled water from a boiler to produce high-pressure steam, which is controlled by valves into the two chambers of the piston, generating power.

An internal combustion engine, which uses fuel, is burned in the course of a two-stroke or four-stroke to produce power.

Turbofan engines use fuel or steam to produce gas, push the blades to rotate to drive the entire coaxial blades to rotate, and draw in more gas to increase the combustion efficiency to produce thrust or speed. A typical example is a jet engine.

Thrust is generated by producing a large amount of gas directly by burning the fuel. A typical example is a fire dragon out of the water, a sky monkey, and a space engine.

The intake stroke is the process by which the control valve opens to allow air and gasoline to enter the cylinder together.

The four strokes of a gasoline engine are:

1. Suction stroke: the intake valve is opened, the piston moves downward, and the mixture of oil and air enters the cylinder, and when the piston moves to the lowest, the intake valve is closed;

2. Compression stroke: the intake valve and exhaust valve are closed, the piston moves upward, the mixture of fuel and air is compressed, when the piston moves to the top, the compression stroke ends, and the mechanical energy will be moved.

Transformed into internal ridge line energy;

3. Power stroke: the spark ignites the mixed gas, and the burning gas expands sharply, pushing the piston downward, and converting the internal energy into mechanical energy;

4. Exhaust stroke: the exhaust valve is opened, the piston is transported upward, and the exhaust gas after combustion is discharged, and when the piston moves to the top, the exhaust valve is closed.

1. Suction stroke: The piston moves from top to bottom, and the flywheel rotates for half a week by inhaling the mixture of air and gasoline.

2. Compression stroke: the piston moves from bottom to top, the flywheel rotates for one-half of a cycle, and the mechanical energy is converted into internal energy.

3. Power stroke: The piston moves from top to bottom, the flywheel rotates for half a week, the internal energy is converted into mechanical energy, and the external work is done once.

4. Exhaust stroke: the piston moves from bottom to top, and the flywheel rotates for half a week (relying on inertia).

The engine converts chemical energy into mechanical energy, and its conversion process is actually the process of the work cycle, simply put, it is through the combustion of fuel in the cylinder, generating kinetic energy, driving the reciprocating movement of the piston in the engine cylinder, thereby driving the connecting rod connected to the piston and the crank connected to the connecting rod, making reciprocating circular motion around the center of the crankshaft, and outputting power.

The working process of a four-stroke gasoline engine is a complex process, which consists of four strokes (strokes) of air intake, compression, combustion expansion, and exhaust.

The four strokes of a stroke gasoline engine are: intake stroke, compression stroke, expansion stroke, and exhaust stroke.

1. Intake stroke.

At this time, the piston is driven by the crankshaft to move from the top dead center to the bottom dead center, and at the same time, the intake valve opens and the exhaust ridge travel door closes. When the piston moves from the top dead center to the bottom dead center, the volume of the Pai Ye key above the piston increases, and the gas pressure in the cylinder decreases, forming a certain vacuum. Since the intake valve is opened, the cylinder communicates with the intake pipe and the mixture is sucked into the cylinder.

When the piston is moved to the bottom dead center, the cylinder is filled with fresh mixture and exhaust gases that were not discharged from the previous duty cycle.

2. Compression stroke.

The piston moves from bottom dead center to top dead center, and the intake and exhaust valves are closed. The crankshaft is driven to rotate under the action of inertial forces such as flywheels, and the piston is pushed upward through the connecting rod, and the gas volume in the cylinder gradually decreases, the gas is compressed, and the pressure and temperature of the mixture in the cylinder increase.

3. Expansion stroke.

At this time, the intake and exhaust valves are closed at the same time, the spark plug is ignited, the mixture is burned violently, the temperature and pressure in the cylinder rise sharply, and the high-temperature and high-pressure gas pushes the piston to move downward, and the crankshaft is driven to rotate through the connecting rod. In the four strokes of the engine work, only this stroke can realize the conversion of heat energy into mechanical energy, so this stroke is also called the work stroke.

4. Exhaust stroke.

The system has resistance, and the combustion chamber also occupies a certain volume, so it is impossible to exhaust the exhaust gas at the end of the exhaust, and the exhaust gas left in this part is called residual exhaust gas. The residual exhaust gas not only affects the inflation, but also has a negative effect on combustion.

Gasoline engine working principle:

By burning the fuel in the cylinder, kinetic energy is generated, and the piston in the engine cylinder is driven to reciprocate, thereby driving the connecting rod connected to the piston and the crank connected to the connecting rod to reciprocate in a circular motion around the center of the crankshaft, and output power. A gasoline engine is an electric spark ignition internal combustion engine that uses gasoline as fuel.

The gasoline engine is mainly composed of a crank connecting rod mechanism, a gas distribution mechanism, a driving mechanism, a fuel supply system, a cooling system, a lubrication system, a starting and ignition system. Taking the valve mechanism as an example, its function is to ensure that when the piston is in a certain position, the valve is opened and closed, so that the combustible mixture enters the cylinder, and the exhaust gas is discharged from the cylinder.

The above content reference: Encyclopedia - gasoline engine.

The working cycle of a four-stroke gasoline engine consists of 4 piston strokes, namely the intake stroke, the compression stroke, the power stroke and the exhaust stroke.

1.Inspiratory stroke. The intake valve is opened, the exhaust valve is closed, the piston moves from the top dead center to the bottom dead center, the cylinder volume above the piston increases, the vacuum degree is generated, the pressure in the cylinder drops below the intake pressure, and under the action of vacuum suction, the gasoline atomized through the carburetor or gasoline injection device is mixed with air to form a combustible mixture, which is sucked into the cylinder by the intake tract and the intake valve.

The intake process continues until the piston passes the bottom dead center and the intake gate closes. Then the ascending piston begins to compress the gas. 2.

Compression stroke. The intake and exhaust valves are all closed, the combustible mixture in the cylinder is compressed, the temperature of the mixture rises, and the pressure rises. Before the piston approaches the top dead center, the pressure of the combustible mixture rises to about 0 6 1 2MPa, and the temperature can reach 330 430.

3.Do the power stroke. As the compression stroke approaches the top dead center, an electric spark spark is emitted by a spark plug mounted above the cylinder head, igniting the compressed combustible mixture.

After combustible mixture combustion, a large amount of heat is released, and the gas pressure and temperature in the cylinder rise rapidly, the maximum combustion pressure can reach 3 6MPa, and the maximum combustion temperature can reach 2 200 2 500. The high-temperature and high-pressure gas pushes the piston to move rapidly to the dead center, and works externally through the crank connecting rod mechanism. At the beginning of the work stroke, the intake and exhaust valves are closed.

4.Exhaust stroke. When the power stroke is nearing the end, the exhaust valve is opened, because the pressure in the cylinder is higher than the atmospheric pressure at this time, the high-temperature exhaust gas is quickly discharged from the cylinder, this stage belongs to the free exhaust stage, and the high-temperature exhaust gas is discharged through the exhaust valve at the local sound speed.

With the exhaust process to enter the forced exhaust stage, the piston moves over the bottom dead center to the top dead center, and the exhaust gas in the cylinder is forcibly discharged, and the exhaust process ends when the piston reaches the vicinity of the top dead center. At the end of the exhaust, the gas pressure in the cylinder is slightly higher than the atmospheric pressure, about 0 105 0 115MPa, and the exhaust gas temperature is about 600 900. Because the combustion chamber occupies a certain volume, it is impossible to completely remove the exhaust gas at the end of the exhaust, and the remaining part of the exhaust gas is called residual exhaust gas.

Photo by Deng Xuequn) @2019

The working cycle of a four-stroke gasoline engine consists of four piston strokes, namely the intake stroke, the compression stroke, the power stroke and the exhaust stroke.

1.Inspiratory stroke. When the intake valve is opened and the exhaust valve is closed, the piston moves from the top dead center to the bottom dead center, the cylinder volume above the piston increases, a vacuum degree is generated, and the pressure in the cylinder drops below the intake pressure.

Under the action of vacuum suction, the gasoline atomized by a carburetor or gasoline injection device is mixed with the air to form a combustible mixture, which is sucked in by the air intake and intake valves. The intake process continues until the piston passes the bottom dead center and the intake valve closes. Then the upward piston begins to compress the gas.

2.Compression stroke. All intake and exhaust valves are closed, the combustible mixture inside the cylinder is compressed, and the temperature and pressure of the mixture rise.

Before the top dead center of the piston, the pressure of the combustible mixture rises to about 330 430. 3.Power stroke.

As the compression stroke approaches the top dead center, a spark plug mounted above the cylinder head emits an electrical spark that ignites the compressed combustible mixture. After combustible mixture combustion, a large amount of heat is released, and the gas pressure and temperature in the cylinder rise rapidly, with a maximum combustion pressure of 3 6MPa and a maximum combustion temperature of 2200 2500. The high-pressure gas pushes the piston to move rapidly to the bottom dead center, and does external work through the crank connecting rod mechanism.

At the beginning of the working stroke, the intake and exhaust valves are closed.

4.Exhaust stroke. At the end of the power stroke, the exhaust valve opens.

Since the pressure in the cylinder is higher than the atmospheric pressure at this time, the hot exhaust gases are quickly discharged from the cylinder. This stage is the free exhaust phase, where the hot exhaust gases are discharged through the exhaust valve at local sound speed. As the exhaust process progresses, it enters the forced exhaust stage, and the piston moves beyond the bottom dead center to reach the top dead center, and the exhaust gas in the cylinder is forcibly discharged.

When the piston reaches the vicinity of the top dead center, the venting process ends. At the end of the exhaust, the gas pressure in the cylinder is slightly higher than the atmospheric pressure, approximately, and the exhaust temperature is about 600 900. Since the combustion chamber occupies a certain volume, it is not possible to completely exhaust the exhaust gases at the end of the exhaust gas, and the remaining part is called residual exhaust gas.

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