Are all the parts of aluminum alloy engine made of aluminum? Tell me about the material of the engine.

What is the material of automobile engine? Some people say that this is not simple, cast iron aluminum alloy! Aluminum alloy engine technology is more advanced, good heat dissipation, light weight and more advanced; Cast iron engine has poor heat dissipation and heavy weight, which is a representative of backward technology. Cast iron engines are now used to save costs, cut corners and so on. ? So is this a fact? In recent years, Chinese people have been completely brainwashed by some car companies, thinking that aluminum alloy engines are made of aluminum alloy and cast iron engines are made of cast iron, so the quality difference between the two is huge. ? But it's not like that at all. The engine consists of two mechanisms and five systems. The so-called cast iron engine and aluminum alloy engine only refer to the materials of the engine cylinder block, and the materials of other parts are basically the same. In other words, there are many iron parts on aluminum alloy engines, and there are also many aluminum alloy parts on cast iron engines. In order to explain the material of automobile engine in detail, we might as well decompose the engine and talk about the material of each component in detail.

1. cylinder block: the cylinder block is the most basic component of the engine, and all other components are directly or indirectly installed on it. ? There are two kinds of cylinder materials, one is cast iron, which is generally cast with gray cast iron. In order to strengthen the cylinder block, the current engine? Strength and wear resistance, but also the use of nickel, chromium, molybdenum, phosphorus and other elements of high-quality gray cast iron. However, some high-strength diesel oil will be cast with more advanced nodular cast iron or vermicular cast iron. The strength, rigidity, wear resistance and vibration absorption of cast iron cylinder block are excellent, but the biggest disadvantage is its heavy weight. ? At present, gasoline engines for small cars mostly use aluminum alloy cylinders or aluminum-magnesium alloy cylinders. They are made of aluminum alloy or aluminum-magnesium alloy, the biggest advantage is light weight and good heat dissipation, but the strength, stiffness, wear resistance and vibration absorption of the cylinder block are not as good as those of the cast iron cylinder block. So those online sprayers who boast that aluminum alloy engines are better all day can rest.

2. Cylinder head: The working conditions and structural complexity of cylinder head and cylinder block have many similarities, so they are generally cast with the same material, which is also gray cast iron or alloy cast iron. In order to improve the heat dissipation performance and reduce the weight of the engine, some gasoline engines will use aluminum alloy to cast cylinder heads. However, aluminum alloy is low in strength and easy to deform in use, so it can only be used in gasoline engines, while diesel engines are cast with higher strength cast iron.

3. Cylinder liner: The cylinder liner is embedded in the cylinder block, and the piston and piston ring move up and down in it, so it must be very wear-resistant. Therefore, it is generally made of high-grade cast iron with good wear resistance, such as pearlite cast iron, alloy cast iron, high phosphorus cast iron and boron-containing cast iron. It should be noted that both cast iron engines and aluminum alloy engines have cast iron cylinder liners, and aluminum alloy engines must also be inlaid with cast iron cylinder liners. Now there is a more advanced technology, that is, directly applying metal spraying technology to the aluminum alloy cylinder block, spraying a dense and wear-resistant iron coating, and then using laser quenching to enhance hardness and wear resistance, which can greatly reduce the weight and volume of the engine. However, such an engine cannot be repaired. In case of cylinder explosion, the engine can only be replaced directly. ? 4. Piston: Whether it is cast iron engine or aluminum alloy engine, the pistons they use are basically aluminum alloy. Silicon-aluminum alloy is widely used, its expansion coefficient and density are small, and its wear resistance is good. A few heavy-duty diesel engines use Cu-Ni-Mg-Al alloy pistons with good high temperature strength and thermal conductivity. At present, some diesel engines also use cast iron pistons, which have excellent performance and good heat resistance, and are consistent with the expansion coefficient of the cylinder block, which can reduce the assembly clearance. The early diesel engine of Xichai 6DL-2 used cast iron pistons, and the engine ran very smoothly. ? 5. Piston ring: The piston ring is in direct contact with the cylinder wall and moves up and down at high speed, so it requires good wear resistance. Piston rings are generally cast with high-quality gray cast iron, alloy cast iron or nodular cast iron, and the friction surface is treated with porous chromium plating or molybdenum spraying to enhance wear resistance and lubrication performance. ? 6. Piston pin: the piston pin connects the piston and the connecting rod, and it has to bear a great continuous impact load in the working process, so it is not suitable for it. The requirements for strength and wear resistance are very high. Generally forged with low carbon steel or low carbon alloy steel, such as 20Cr and 20MnV. The surface should be carburized or cyanided, so as to obtain higher surface hardness, good wear resistance and high strength, and at the same time have a better impact-resistant soft core.

7. Connecting rod: The connecting rod connects the piston with the crankshaft, converts the reciprocating linear motion of the piston into the rotary motion of the crankshaft, and transmits the force on the piston to the crankshaft. It must bear alternating bending load in its work. Generally, it is forged with medium carbon alloy steel such as 40Cr, and the surface is shot peened to improve the fatigue strength.

8. Crankshaft: The crankshaft is one of the most important parts of the engine. It is the power output element of the engine. When working, it bears periodically changing gas pressure, reciprocating inertia force and centrifugal force. The working conditions are extremely complicated, so the requirements for its materials are also extremely high. Crankshaft is generally forged with high-quality medium carbon steel or medium carbon alloy steel, and large diesel engines are generally cast with ductile iron, and the surface is strengthened by shot peening. Some crankshaft surfaces should be nitrided to improve fatigue strength.

9. Camshaft: The camshaft is one of the most important parts in the valve mechanism. Its working conditions are similar to those of crankshaft. Generally, it is forged with high-quality carbon structural steel or alloy structural steel, and the cam surface is quenched by high-frequency quenching or carburizing to improve wear resistance and surface hardness. At present, some models use alloy cast iron or nodular cast iron to cast camshafts.

10, valve: the valve is a part of the engine valve train, which is used to control air to enter the cylinder and exhaust the exhaust gas after engine combustion. Its biggest feature is that it can withstand the high temperature of combustion, so valves are generally made of heat-resistant steel, such as silicon chrome steel, silicon chrome molybdenum steel, silicon chrome manganese steel and so on. Some valves will be coated with a layer of tungsten-cobalt alloy by surfacing or plasma spraying to improve corrosion resistance and high temperature resistance. In addition, in order to enhance heat dissipation, some valves are also equipped with metal sodium, which flows into the interior after being heated and melted, bringing the heat of the valve head to the valve stem and radiating it out. ? 1 1. Valve seat ring: The valve seat ring cooperates with the valve and is embedded in the cylinder head. Its working conditions are similar to those of valves, and generally the same as those of valves. Made of heat-resistant alloy steel or alloy cast iron. ? 12. Valve spring: The function of the valve spring is to make the valve automatically return and close, and ensure the seating pressure between the valve and the valve seat. In addition, it is necessary to absorb the inertia force of the valve during opening and closing. Generally, high-quality cold-drawn spring steel wire is used, and after heat treatment, the surface is polished or shot peened.

13. Valve cover: The valve cover is used to seal the valve chamber to prevent oil splashing. Generally, thin steel plate is used for stamping, and some models use aluminum alloy valve covers. Their functions are the same, and there is no distinction between high and low. In order to strengthen thermal insulation, some models will use plastic or resin materials with poor heat dissipation to make valve covers.

14. oil pan: the oil pan is installed at the bottom of the engine to hold oil. Generally, it is stamped from thin steel plate, and some models are cast from aluminum alloy. Relatively speaking, the oil pan cast by aluminum alloy has better heat dissipation, but its impact resistance and collision resistance are poor, so it will be damaged by impact. Unlike the oil pan made of thin steel plate, it may be deformed only when it is hit, but it will not damage the oil leakage.

The above is the material distribution of the main parts in the engine. In fact, the materials used in the engine are not only these, but also various other rubber parts (such as various oil seals). ), alloy parts (such as bearing shells, copper sleeves at various parts, etc. ), and various metallic and nonmetallic materials such as copper, tin, resin and plastic are also on the engine accessories. In a word, the engine is not made of one material, but is made of many materials. The quality of these materials largely determines the quality of the engine. We often say that the quality of Japanese engines is good, largely because of better materials and technology.