The car engine is a complex mechanism, one of the most important elements of which is the camshaft, which is part of the timing. The correct operation of the engine largely depends on the precise and trouble-free operation of the camshaft.
One of the most important functions in the operation of a car engine is performed by the camshaft, which is an integral part of the gas distribution (synchronization) mechanism. The camshaft provides the intake and exhaust strokes of the engine.
Depending on the engine design, the gas distribution mechanism may have a lower or upper valve arrangement. Today, timing belts with overhead valves are more common. This design allows for faster and easier maintenance, which includes adjusting and repairing the camshaft, which requires camshaft parts.
From a structural point of view, the engine camshaft is connected to the crankshaft, which is ensured by the presence of a chain and a belt. The camshaft chain or belt slips on the crankshaft sprocket or camshaft pulley. A camshaft pulley such as a split gear is considered the most practical and efficient option, so it is often used to tune engines to increase their power.
The bearings, inside which the camshaft journals rotate, are located on the cylinder head. If the journal holders fail, repair camshaft liners are used to fix them.
In order to avoid axial play, special retainers are included in the design of the camshaft. Directly along the axis of the shaft there is a through hole designed for lubrication of friction parts. This hole is closed at the rear using a special camshaft plug
The most important part of the camshaft is the cams, the number of which indicates the number of intake and exhaust valves. The cams are responsible for performing the main function of the camshaft - adjusting the valve timing of the engine and regulating the order of operation of the cylinders.
Each valve is equipped with a cam. The cam rides over the tappet, helping to open the valve. After the cam leaves the tappet, a strong return spring closes the valve.
The camshaft cams are located between the bearing journals. The timing of the camshaft gas distribution, which depends on the engine speed and the design of the intake and exhaust valves, is determined empirically. Similar data for a specific engine model can be found in special tables and diagrams specially compiled by the manufacturer
The main function of the camshaft (camshaft) is to ensure the opening / closing of the intake and exhaust valves, with the help of which the fuel assemblies (air-fuel mixture) are supplied and the gases formed. The camshaft is the main part of the timing (gas distribution mechanism), which participates in the complex process of gas exchange in a car engine.
The modern timing belt can be equipped with one or two camshafts. In a single shaft mechanism, all intake and exhaust valves are serviced at the same time (1 intake and exhaust valve per cylinder). In a mechanism equipped with two shafts, one camshaft drives the intake valves, the other shaft drives the exhaust valves (2 intake and exhaust valves per cylinder).
The location of the gas distribution mechanism directly depends on the type of car engine. Distinguish the distribution with an upper valve arrangement (in the cylinder block) and a lower valve arrangement (in the cylinder head).
The most common option is the overhead location, which effectively adjusts and holds the camshaft.
The principle of operation and the device of the camshaft
The gas distribution phases are defined according to the alignment marks which are on the gears or the pulley. Proper installation ensures that the engine cycles in sequence.
The cams are the main part of the camshaft. In this case, the number of cams with which the camshaft is equipped depends on the number of valves. The main purpose of the cams is to adjust the phases of the gassing process. Depending on the type of timing design, the cams may interact with a rocker arm or a tappet.
The cams are installed between the bearing journals, two for each engine cylinder. During operation, the camshaft must overcome the resistance of the valve springs, which serve as a mechanism fore recall, bringing the valve to its original (closed) position.
Overcoming these stresses requires the engine's useful power, so designers are constantly thinking about how to reduce power losses.
In order to reduce the friction between the tappet and the cam, the tappet can be equipped with a special roller.
In addition, a special desmodromic mechanism has been developed, in which a springless system is implemented.
The camshaft holders are equipped with covers, the front cover being shared. It has thrust flanges which are connected to the shaft journals.
The camshaft is made in two ways: steel forging or cast iron.
timing systems
As mentioned above, the number of camshafts corresponds to the type of engine.
In in-line engines with a pair of valves (one intake and one exhaust valve each), the cylinder is fitted with a single shaft. In-line engines with two pairs of valves have two shafts.
Currently, modern engines can be equipped with various valve timing systems:
VVT-i. In this technology, the phases are adjusted by turning the camshaft relative to the pinion on the drive.
Valvetronic. The technology allows you to adjust the valve lift by moving the axis of rotation of the rocker arm
VTEC. This technology involves regulating the phases of gas distribution through the use of cams on an adjustable valve
So, to sum up ... the camshaft, being the main link in the gas distribution mechanism, provides rapid and precise opening of the engine valves. This is ensured by precise adjustment of the shape of the cams which, by pushing the tappets, cause the valve to move.
The car engine is a complex mechanism, one of the most important elements of which is the camshaft, which is part of the timing. The correct operation of the engine largely depends on the precise and trouble-free operation of the camshaft.
One of the most important functions in the operation of a car engine is performed by the camshaft, which is an integral part of the gas distribution (synchronization) mechanism. The camshaft provides the intake and exhaust strokes of the engine.
Depending on the engine design, the gas distribution mechanism may have a lower or upper valve arrangement. Today, timing belts with overhead valves are more common. This design allows for faster and easier maintenance, which includes adjusting and repairing the camshaft, which requires camshaft parts.
From a structural point of view, the engine camshaft is connected to the crankshaft, which is ensured by the presence of a chain and a belt. The camshaft chain or belt slips on the crankshaft sprocket or camshaft pulley. A camshaft pulley such as a split gear is considered the most practical and efficient option, so it is often used to tune engines to increase their power.
The bearings, inside which the camshaft journals rotate, are located on the cylinder head. If the journal holders fail, repair camshaft liners are used to fix them.
In order to avoid axial play, special retainers are included in the design of the camshaft. Directly along the axis of the shaft there is a through hole designed for lubrication of friction parts. This hole is closed at the rear using a special camshaft plug
The most important part of the camshaft is the cams, the number of which indicates the number of intake and exhaust valves. The cams are responsible for performing the main function of the camshaft - adjusting the valve timing of the engine and regulating the order of operation of the cylinders.
Each valve is equipped with a cam. The cam rides over the tappet, helping to open the valve. After the cam leaves the tappet, a strong return spring closes the valve.
The camshaft cams are located between the bearing journals. The timing of the camshaft gas distribution, which depends on the engine speed and the design of the intake and exhaust valves, is determined empirically. Similar data for a specific engine model can be found in special tables and diagrams specially compiled by the manufacturer
The main function of the camshaft (camshaft) is to ensure the opening / closing of the intake and exhaust valves, with the help of which the fuel assemblies (air-fuel mixture) are supplied and the gases formed. The camshaft is the main part of the timing (gas distribution mechanism), which participates in the complex process of gas exchange in a car engine.
The modern timing belt can be equipped with one or two camshafts. In a single shaft mechanism, all intake and exhaust valves are serviced at the same time (1 intake and exhaust valve per cylinder). In a mechanism equipped with two shafts, one camshaft drives the intake valves, the other shaft drives the exhaust valves (2 intake and exhaust valves per cylinder).
The location of the gas distribution mechanism directly depends on the type of car engine. Distinguish the distribution with an upper valve arrangement (in the cylinder block) and a lower valve arrangement (in the cylinder head).
The most common option is the overhead location, which effectively adjusts and holds the camshaft.
The principle of operation and the device of the camshaft
The gas distribution phases are defined according to the alignment marks which are on the gears or the pulley. Proper installation ensures that the engine cycles in sequence.
The cams are the main part of the camshaft. In this case, the number of cams with which the camshaft is equipped depends on the number of valves. The main purpose of the cams is to adjust the phases of the gassing process. Depending on the type of timing design, the cams may interact with a rocker arm or a tappet.
The cams are installed between the bearing journals, two for each engine cylinder. During operation, the camshaft must overcome the resistance of the valve springs, which serve as a mechanism fore recall, bringing the valve to its original (closed) position.
Overcoming these stresses requires the engine's useful power, so designers are constantly thinking about how to reduce power losses.
In order to reduce the friction between the tappet and the cam, the tappet can be equipped with a special roller.
In addition, a special desmodromic mechanism has been developed, in which a springless system is implemented.
The camshaft holders are equipped with covers, the front cover being shared. It has thrust flanges which are connected to the shaft journals.
The camshaft is made in two ways: steel forging or cast iron.
timing systems
As mentioned above, the number of camshafts corresponds to the type of engine.
In in-line engines with a pair of valves (one intake and one exhaust valve each), the cylinder is fitted with a single shaft. In-line engines with two pairs of valves have two shafts.
Currently, modern engines can be equipped with various valve timing systems:
VVT-i. In this technology, the phases are adjusted by turning the camshaft relative to the pinion on the drive.
Valvetronic. The technology allows you to adjust the valve lift by moving the axis of rotation of the rocker arm
VTEC. This technology involves regulating the phases of gas distribution through the use of cams on an adjustable valve
So, to sum up ... the camshaft, being the main link in the gas distribution mechanism, provides rapid and precise opening of the engine valves. This is ensured by precise adjustment of the shape of the cams which, by pushing the tappets, cause the valve to move.
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