Engine cooling system in the carIt is designed to protect the unit from overheating and thus controls the performance of the entire engine block. Cooling is the most important function in the operation of an internal combustion engine.
The consequences of a malfunction of cooling ICE canto become fatal for the unit itself, up to the complete failure of the cylinder block. Damaged nodes may not be subject to repair works, their maintainability will be zero. It should be with all care and responsibility to take care of the operation and conduct periodic cleaning of the engine cooling system.
Controlling the cooling system, the car owner directly takes care of the "health of the heart" of his iron "horse".
The temperature in the cylinder block while runningThe unit can rise to 1900 ℃. Of this amount of heat, only a part is useful and is used in the required modes of operation. The rest is output by the cooling system outside the engine compartment. An increase in the temperature regime above the norm is fraught with negative consequences that lead to the burning of lubricants, the violation of technical clearances between certain parts, especially in the piston group, which will lead to a reduction in their service life. Overheating of the motor, as a result of a malfunction of the engine cooling system, is one of the causes of the detonation of the combustible mixture supplied to the combustion chamber.
Subcooling the engine is also undesirable.In the "cold" unit there is a loss of power, the density of the oil rises, which increases the friction of ungreased assemblies. The working combustible mixture is partially condensed, thereby depriving the cylinder walls of the lubricant. At the same time, the wall surface of the cylinder undergoes a corrosion process due to the formation of sulfur deposits.
The engine cooling system is designed to stabilize the thermal regime necessary for the normal operation of the motor of the vehicle.
The engine cooling system is classified according to the heat removal method:
Currently, air cooling incars is extremely rare. The fluid can be of an open type. In such systems, heat removal takes place through the steam pipe to the environment. The closed system is isolated from the external atmosphere. Therefore, the pressure in the engine cooling system of this type is much higher. At high pressures, the cooling threshold for the cooling element increases. The refrigerant temperature in the closed system can reach 120 ℃.
Natural supply air coolingmasses is the simplest way to remove heat. Motors with this type of cooling emit heat to the environment with the help of radiator fins located on the surface of the unit. Such a system has a huge lack of functionality. The fact is that this method directly depends on the small specific heat of air. In addition, there are problems with the uniformity of heat removal from the motor.
Such nuances prevent mounting at the same timeefficient and compact installation. In the engine cooling system, air flows unevenly into all parts, and then it is necessary to avoid the possibility of local overheating. Following the design features, the fins for cooling are mounted in those places of the engine, where the air masses are least active, due to aerodynamic properties. Those parts of the motor, which are most prone to heat, are arranged to meet the air masses, while the more "cold" areas are placed behind.
Motors with this type of excess heat removalequipped with a fan and cooling fins. Such a set of structural units allows artificially pumping air into the engine cooling system to blow cooling fins. Above the fan and ribs a protective casing is installed, which participates in the direction of air masses for cooling and prevents heat from entering from outside.
Positive moments in this type of coolingsimplicity of design features, low weight, absence of feeding and refrigerant circuits is assumed. The disadvantages are the high noise level of the system functioning and the unwieldiness of the device. Also in forced air cooling, the problem with the local overheating of the unit and the absent-mindedness of the blowing, despite the installed casings, has not been solved.
This type of engine overheat warningactively used until the 70's. The work of the engine cooling system with forced air type was popular on small vehicles.
The liquid cooling system for today isthe most popular and widespread. The process of heat removal takes place with the help of liquid refrigerant circulating along the main engine elements via special closed highways. The hybrid system combines elements of air cooling with liquid at the same time. The liquid is cooled in a radiator having fins and a fan with a casing. Also, such a radiator is cooled by supply air masses when the vehicle is moving.
The liquid cooling system of the engine gives the minimum noise level during operation. This type collects heat all over the place and diverts it from the engine with high efficiency.
By the method of movement of liquid refrigerant systems are classified:
The design of liquid cooling has the same structure and elements, both for a gasoline engine and for a diesel engine. The system consists of:
When flushing the engine cooling system, all these nodes (except the fan) are affected for more efficient further operation.
The coolant circulates through the pipelinesinside the block. The totality of such passes is called the "cooling jacket". It covers the most exposed areas of the engine. Refrigerant, moving along it, absorbs heat and carries it to the radiator block. Cooling, he repeats the circle.
One of the main elements in the device systemcooling the engine is considered a radiator. Its task is to cool down the coolant. It consists of a radiator grate, inside which tubes for the movement of liquid are laid. The cooling liquid enters the radiator through the lower branch pipe and exits through the upper one, which is mounted in the upper tank. Above the tank there is a neck, closed with a lid with a special valve. When the pressure in the engine cooling system increases, the valve opens slightly and the fluid enters the expansion tank, which is attached separately in the engine compartment.
Also on the radiator there is a temperature sensor,which signals the driver about the maximum heating of the liquid by means of a device installed in the passenger compartment on the information panel. In most cases, a fan (sometimes two) with a casing is attached to the radiator. The fan is activated automatically when the critical coolant temperature is reached or is forced from the drive with the pump.
The pump ensures a constant circulation of the cooling liquid throughout the system. Rotational energy of the pump is obtained by a belt drive from the crankshaft pulley.
Thermostat controls a large and small circlecoolant circulation. At the first start-up of the engine, the thermostat starts up the liquid in a small circle so that the engine unit warms up to operating temperature faster. After that, the thermostat opens a large circle of the engine cooling system.
Water is used as a coolant.or antifreeze. Modern car owners are increasingly using the latter. Water freezes at sub-zero temperatures and is a catalyst in corrosion processes, which adversely affects the system. The only advantage is its high heat transfer and more, perhaps, availability.
Antifreeze does not freeze when cold, preventscorrosion, prevents sulfur deposits in the engine cooling system. But it has a lower heat transfer, which negatively affects the hot season.
The consequences of a cooling problem areengine overheating or overcooling. Overheating can be caused by insufficient fluid in the system, unstable operation of the pump or fan. Also the thermostat malfunctions when it should open a large circle of cooling.
Неисправности системы охлаждения двигателя могут be caused by heavy pollution of the radiator, slagging of highways, poor performance of the radiator cap, expansion tank or poor quality antifreeze.
