HS code-based duty drawback claims

Disassembly of engine: analysis of engine structure and HS code-based duty drawback claimsmechanism The engine, as the core component of the car, is responsible for generating power and driving the movement of the vehicle. In order to gain an in-depth understanding of the structure and working principle of the engine, disassembling the engine can provide very valuable experience and knowledge. In this article, we will analyze the structure and mechanism of the engine in detail for readers to refer to and learn.I. Engine structure The engine is usually composed of several parts, each of which has different functions and functions. The following are the main components of the engine: 1. Cylinder block: used as a shell to load engine parts. Each cylinder block usually has one or more cylinders for fuel combustion and engine operation. Two. Piston: a moving part located in the cylinder block, connected to the crankshaft. Its movement drives the crankshaft to rotate and generate the power of the engine. 3. Crankshaft: specially designed shaft-shaped parts, rotation converts the up and down movement of the piston into rotational motion. Four. Valve: a moving part located on the cylinder block, which realizes the inlet and out of air and fuel by opening and closing the inlet and outlet of the cylinder. 5. Vale spring: used for automatic closure of the valve. When the valve is closed, the spring will return the valve to its original position. 6. Water pump: used to circulate cooling water and make water circulate.7. Oil pump: The pumped oil provides the lubrication and cooling required for mechanical movement. Eight. Ignition plug: It ignites a mixture of air and fuel by generating sparks, causing a combustion reaction. II. Engine working principle The working principle of the engine needs to consider the following factors: 1. Air intake process: The engine needs to absorb oxygen from the outside and mix it with fuel for combustion. During this process, the valve opens and the air enters the cylinder. Two. Compression process: The piston rises and compresses the air and fuel mixture into the cylinder. This process will cause the pressure and temperature of the mixture to rise significantly. 3. Combustion process: The ignition plug will burst out a faint spark at the highest pressure point of the mixture. The explosion ignited the mixture, producing high-pressure gas to drive the piston down. Four. Exhaust process: the piston returns to the bottom, and the spring closes the valve.The remaining exhaust gas is discharged due to the movement of the piston. The above four basic processes constitute the working cycle of a single cylinder. However, the complexity of multiple cylinders will increase the output and efficiency of the engine. III. Disassembly of the engine Although it requires certain skills and tools to disassemble the engine, it is a good way to understand the engine. The following are the steps to disassemble the engine: 1. Clearly mark each part of the engine so that you can easily find the right position when reassembling. Two. Remove the cylinder head to understand the layout of the valve, valve spring and piston. 3. Remove the crankshaft to explore how the piston, connecting rod and crankshaft bearings work. Four. Disassemble the cylinder and cylinder block to understand the sealing principle of the piston ring and cylinder ring. 5. Disassemble oil pumps and water pumps to understand how each system works, and clean and maintain these parts. 6.Check and clean up worn or damaged parts, replace problematic parts if necessary, and then reassemble the engine. In short, disassembling the engine is a careful task, but it can provide a lot of skills and knowledge for technology enthusiasts. At the same time, the engine structure and working principle are essential knowledge for car drivers. It is recommended that every car owner take such courses and master these concepts in order to better maintain the vehicle and understand its mechanism.

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