What is four-stroke internal combustion engine?

Turn the crankshaft two turns (720 °), the piston in the cylinder up and down reciprocating motion four strokes, complete a work cycle of the internal combustion engine called four-stroke internal combustion engine. Four-stroke internal combustion engine is in four working strokes to complete a work cycle of the internal combustion engine. It is a kind of heat engine.

1. Basic Information

When the piston reciprocates in the cylinder, the process of moving from one end of the cylinder to the other is called a stroke. Most of the ordinary internal combustion engines are four-stroke internal combustion engines. It is divided into suction stroke, compression stroke, work stroke and exhaust stroke. There are mainly four-stroke gasoline engines and four-stroke diesel engines. The earliest four-stroke internal combustion engine uses the fuel of gas.

In 1876, Otto built a new, gas-fueled four-stroke internal combustion engine.

2. Working Process

Suction Stroke

The intake valve opens, the exhaust valve closes, the piston moves downward, and the gasoline and air mixture enters the cylinder.

Compression stroke

The intake and exhaust valves are closed, the piston moves upward, and the gasoline and air mixture is compressed. Mechanical energy is converted into internal energy.

Work stroke

At the end of the compression stroke, the spark plug generates an electric spark that causes the fuel to burn violently, producing high temperature and high pressure gas. The high-temperature and high-pressure gas pushes the piston downward and drives the crankshaft to do external work. Among the four strokes, only the work stroke does external work, the other three strokes are done by the inertia of the work stroke. Internal energy is converted into mechanical energy.

Exhaust stroke

The intake valve is closed, the exhaust valve is opened, and the piston moves upward to expel the exhaust gas from the cylinder.

3. Workflow

Six-stroke internal combustion engine, including cylinder, piston, intake valve, exhaust valve and crankshaft, its completion of a working cycle includes cylinder, piston, intake valve, exhaust valve and crankshaft, its completion of a working cycle includes suction stroke, compression stroke, work stroke, said suction stroke is, the intake valve opens, the piston moves from the upper stop to the lower stop, the mixture is sucked into the cylinder, compression stroke is, the intake valve closes, the piston moves from the lower stop to the upper stop, the mixture in the cylinder is compressed, the work stroke is, the piston moves close to the upper stop, the spark plug ignites in advance, the mixture is burned, the combustion produces high temperature. The compression stroke is, the intake valve is closed, the piston moves from the lower stop point to the upper stop point, the mixture is compressed in the cylinder, the work stroke is, the piston moves close to the upper stop point, the spark plug ignites in advance, the mixture is burned, the combustion produces high temperature and high pressure gas expansion in the cylinder, the piston is pushed from the upper stop point to the lower stop point.

4. Technical characteristics

Compared with the four-stroke internal combustion engine, there are three advantages: from the economy of its fuel consumption compared to the four-stroke internal combustion engine only one-half; from the power compared to its power than the four-stroke internal combustion engine is 35% larger; from the environmental aspects compared to its harmful exhaust emissions only one-half of the four-stroke internal combustion engine. Its characteristics are: the piston moves to the lower stop, the beginning of the compression stroke, the exhaust door open, part of the exhaust gas quickly, the exhaust door closed, the piston moves from the lower stop to the upper stop, the remaining part of the cylinder of high-temperature gas is compressed, the piston moves to the upper stop, the beginning of the water jet expansion stroke, the water jet pump through the cylinder with the water jet nozzle to the cylinder, water contact to the hot flaming gas, water explosion, the water mixture expands rapidly in volume. The volume of the vapor mixture expands rapidly, the resulting high-pressure gas to push the piston from the upper stop point to the lower stop point, and finally the exhaust stroke, the exhaust door opens for the second time, the exhaust gas and water vapor is rapidly discharged.

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