How does a diesel engine work?

How does a diesel engine work?

1. How does a diesel engine produce energy?

Diesel combustion in the cylinder (oil + gas) generates kinetic energy, driving the crank connecting rod mechanism connected with the piston to reciprocate circular motion around the crankshaft, output power.

2. How is energy converted?

The chemical energy of diesel oil is converted to heat energy, which is converted to mechanical energy.

3. What are the four strokes of a four-stroke diesel engine?

Intake stroke (oil and gas mixture), compression stroke, power stroke, exhaust stroke, each time four strokes reciprocating cycle.

4. Crankshaft rotation Angle in a working cycle of four-stroke diesel engine?

Four-stroke diesel engines turn the crankshaft twice (180*4=720) in a single working cycle, theoretically doubling the power of two-stroke (now obsolete) diesel engines.

5. Diesel ignition mode?

Diesel engines use diesel as a fuel. Compared with gasoline, diesel has a lower natural temperature, higher viscosity and is not easy to evaporate. So the diesel engine at the compression end of the compression ignition, do not need a special spark plug.

How does a diesel engine work?


6. How does a diesel engine achieve supercharging?

Compressed air is to improve the oxygen density in the air, when the oxygen density increases, the oil can be fully combustion, improve engine power.Yanmar have a high quality diesel engine here.  In LandKingParts we sell yanmar engine parts for farm machinery, heavy trucks and other large machinery, and  westerbeke engine parts. If you need, welcome to buy!The principle of turbocharging is that when the engine speed rises to a certain speed, the exhaust gas from the engine drives the turbine to rotate, and the turbine drives the compressor to work. The high-temperature and high-pressure gas passing through the compressor is cooled into low-temperature high-pressure gas and fed into the cylinder to realize the turbocharging process. Turbocharging actually increases torque/power.

7.What is the working principle of a four-impulse diesel engine?

1) air intake, compression stroke

The piston moves upward from BDC, and the exhaust gas turbo sends fresh air with a certain pressure into the cylinder; When the piston runs to a certain point, blocking the scavenging port, the cylinder becomes closed, the piston continues to go up, and the pressure in the cylinder gradually increases.

2) expansion, exhaust stroke

At a certain moment before the piston runs to TDC, the fuel is sprayed into the combustion chamber in a good atomized state by the injector and mixed with air for self-ignition and combustion. When the piston crosses TDC, the gas pressure and temperature in the cylinder rise sharply. Under the action of high temperature and high pressure gas, the piston moves from TDC to TDC, passing the power to the crankshaft through the connecting rod, and the crankshaft outputs power in the form of rotation. As the piston goes down, the cylinder volume increases gradually, and the pressure and temperature of the gas decrease gradually. Until the exhaust valve opens.

8. Working principle of four-impulse diesel engine?

The working process of diesel engine is actually the same as that of gasoline engine. Each working cycle also experiences four strokes of intake, compression, work and exhaust.

1.) Intake stroke

The working medium entering the cylinder is pure air. Because diesel engine intake system resistance is small, intake terminal pressure PA = (0.85~0.95) P0, higher than gasoline engine. Inlet terminal temperature Ta=300~340K, lower than gasoline engine.

The task of the intake is to fill the cylinder with fresh air. When the intake stroke begins, the piston is at TDC and some exhaust gas remains in the combustion chamber of the cylinder. As the crankshaft rotates the elbow, the connecting rod moves the piston from TDC to TDC, while the intake valve is opened by means of a drive mechanism associated with the crankshaft. As the piston moves down, the volume above the piston in the cylinder increases: the air pressure in the cylinder is lower than the pressure in the intake pipe, so the outside air is constantly being filled into the cylinder.

2) Compression stroke

Because the working medium of compression is pure air, the compression ratio of diesel engine is higher than that of gasoline engine (generally ε=16~22). The pressure of the compression end point is 3 000~5 000 kpa, and the temperature of the compression end point is 750~1 000K, which is much higher than the spontaneous combustion temperature of diesel oil (about 520K).

3) Do power stroke

When the compression stroke is near the end, under the action of high pressure oil pump, the diesel oil is injected into the cylinder combustion chamber through the injector at a high pressure of about 10MPa, and it is immediately ignited after mixing with the air in a very short time. The pressure of the gas in the cylinder rises rapidly, the highest is 5 000~9 000 kpa, and the highest temperature is 1 800~2 000K. Because the diesel engine is self-ignition combustion by compression, it is called compression combustion engine.

4) Exhaust stroke

Diesel engine exhaust is basically the same as gasoline engine, but the exhaust temperature is lower than gasoline engine. Generally the Tr = 700 ~ 900 k. For the single cylinder engine, its speed is not uniform, the engine work is not smooth, vibration. This is because only one of the four strokes is used for work; the other three are used to prepare for work. To solve this problem, the flywheel must have a large enough moment of inertia, which in turn leads to an increase in overall engine mass and size. The use of multi – cylinder engines can make up for the above shortcomings. Modern cars mostly use four cylinder, six cylinder and eight cylinder engines.

Because the working principle of diesel engine is to compress the gas itself, rely on combustion to generate power, and drive the flywheel rotation, to store energy for the next work, produce more exhaust pollution, so gradually more and more cars switch to gasoline or even new energy to replace diesel.


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