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The cylinder block 1
Introduction:
is an engine body, each of the cylinders and the crankcase will fused, is mounted a piston, a crankshaft and other bearing skeleton parts and accessories. On modern vehicles are substantially water-cooled multi-cylinder engine, for a multi-cylinder engine, the cylinders are arranged in the form determines the dimensions and structural characteristics of the engine, on the stiffness and strength also affect the engine block, and arranged in relation to the overall vehicle.
Properties:
The operating conditions of the cylinder block is poor. It is subjected to abrupt changes in the combustion process and the pressure and temperature of the strong friction of the piston movement. Thus, it should have the following properties:
have sufficient strength and rigidity, small deformation, guarantee the correct position of the respective moving parts, in normal operation, noise and vibration.
has a good cooling performance, a cooling water jacket around the cylinder, so that the cooling water heat away.
wear, the cylinder block in order to ensure adequate service life. The upper portion of the cylinder block cylinder bores are parallel, the current multi-lined cylinder liner. The lower portion of the cylinder block is a crankcase for the crankshaft mounting, the installation of various accessories which may be external generator, the engine brackets and the like. Most of the cylinder block of cast iron or cast aluminum, aluminum alloy cylinder high cost, yet lightweight, good cooling performance, more and more widely used. The engine body is composed of a skeleton, an engine mounting base is agencies and system, which the inner and outer mounting parts and accessories of all major engine, subjected to various loads. Therefore, the body must have sufficient strength and rigidity. Organism group is mainly composed of a cylinder block, crankcase, cylinder head gasket and a cylinder head and other parts.
Cylinder Category:
The water-cooled engine cylinder block and the crankcase is often cast in one piece, referred to as a cylinder block mdash; mdash; crankcase, also known as cylinder block. A cylinder block is generally gray cast ironCast, the upper cylindrical cavity of the cylinder block is called a cylinder, the lower half of the crankcase supporting the crankshaft, which crankshaft lumen spatial movement. Cast in the cylinder body has many ribs, the lubricating oil passage cooling water jacket and the like.
The cylinder block should have sufficient strength and rigidity, the cylinder block and the oil pan mounting positions according to different planes, the cylinder block is generally divided into the following three forms.
(1) a cylinder block of general formula: which is characterized by mounting the oil pan of crankshaft rotation center plane and at the same height. The advantage of this cylinder block body height is small, lightweight, compact, easy to process, to facilitate disassembly of the crankshaft; but its drawback is a poor rigidity and strength.
(2) a cylinder block gantry: characterized by an oil pan mounted below the plane of the center of rotation of the crankshaft. The advantage is that the strength and stiffness are good, can withstand a greater mechanical loads; but its drawback is poor manufacturability, bulky structure, processing more difficult.
(3) tunnel cylinder body: a main crankshaft bearing hole of the cylinder block of such a monolithic form, using the rolling bearing, the main bearing hole larger, the crankshaft is loaded from the rear cylinder body. The advantage is a compact construction, good stiffness and strength, but its disadvantage is the high precision machining process is poor, not convenient disassembly of the crankshaft.
The cylinder block cooling:
cylinders arranged in two rows, left and right two cylinders on the same horizontal plane, i.e. the angle between the left and right two cylinder centerline gamma; = 180deg ;, referred boxer. It is characterized by a high degree of small, convenient overall layout is conducive to air cooling. Such small cylinder applications.
In order to work the inner surface of the cylinder at a high temperature, must be suitably cooled cylinder and a cylinder head. There are two methods of cooling a water-cooled, the other is cooled. Around the cylinder and the cylinder head are cooled engine water jacket cooling process, the cylinder block and the cylinder head cooling water jacket communicates, constantly circulating the cooling water in the water jacket, the heat away portion, built of cylinders and cooling.
Cylinder arrangement:
On modern cars are substantially water-cooled multi-cylinder engine, for a multi-cylinder engine, the cylinders are arranged in the form determines the size and shape of the engine junctionConfiguration characteristics of rigidity and strength also affect the engine block, and arranged in relation to the overall vehicle. In a different arrangement of cylinders, the cylinder block may further be divided into single-type, V-type and opposed-three ways:
(1) in-line
the individual cylinders of the engine arranged in a row, usually vertically arranged. Simple single cylinder structure, easy to process, but the length and height of the engine is large. Usually six-cylinder engine with the use of single-row.
For example Jetta, Beverly cars, red car engines are used with this inline cylinder block. Some cars in order to reduce the height of the engine, the engine is tilted at an angle.
(2) Type V
cylinders arranged in two rows, two left and right cylinder axis angle gamma; lt; 180deg ;, referred to as V-type engine, V-type engine with inline compared with the engine, the shorter body length and height, increases the rigidity of the cylinder block, reducing the weight of the engine, but the engine width increase, and the shape is complex, difficult processing, generally used for more than eight-cylinder engine, 6 cylinder engine has a cylinder block with this form.
(3) mounted on the
cylinders arranged in two rows, left and right two cylinders on the same level, i.e., left and right two cylinder axis angle gamma; = 180deg ;, referred boxer. It is characterized by a high degree of small, convenient overall layout is conducive to air cooling. Such small cylinder applications.
of the cylinder liner in two forms:
is called the cylinder bore directly integral cylinder on the cylinder block, cylinder integral strength and stiffness are good, can withstand greater load, such materials require high cylinder, high cost. If the cylinder is manufactured as a separate cylindrical element (i.e. a cylinder liner), and installed in the cylinder block. Thus, the cylinder liner is made of high wear-resistant material, a cylinder block lower prices generally available material, thereby reducing manufacturing costs. Meanwhile, the cylinder liner may be removed from the cylinder block, thereby facilitating repair and replacement, and can greatly extend the life of the cylinder block.
of the cylinder liner has a dry and a wet cylinder liner cylinder liner in two ways:
Dry GasCharacteristics of the cylinder liner is set back into the cylinder body, the outer wall thereof not in direct contact with the cooling water, and in direct contact with the wall surface of the cylinder block, thin wall thickness, typically 1 ~ 3mm. It has the advantage of the monoblock, strength and stiffness are good, but the process is more complex, the inner and outer surfaces need to be finished, convenient disassembly, poor heat dissipation.
is characterized by a wet cylinder liner into the cylinder after the cylinder body suit, the outer wall thereof in direct contact with the cooling water, the cylinder liner only in the upper and lower zones have a circular ring and the cylinder block contact with a wall thickness of typically 5 to 9mm. It is good heat dissipation, uniform cooling, easily processed, usually only the inner surface of the finish, and an outer surface in contact with water does not need processing, easy accessibility, but the drawback is the strength, stiffness is not good such as a dry cylinder liner, and prone water leakage. We should take some measures to leak.
the number of cylinders:
the number of cylinders: Number of cylinders commonly used in automobile engine has 3,4,5,6,8,10,12 cylinder. Displacement of 1 liter three-cylinder engine used, usually 1 to 2.5 l four-cylinder engine, the engine is generally about 3 liter 6 cylinder, 8-cylinder about four liters, 5.5 liters 12-cylinder engine. In general, in the same bore, the more the number of cylinders, the greater the displacement, the higher power; in the same displacement, the more the number of cylinders, the smaller the bore, the rotational speed can be increased to obtain a larger increase power.