Car engine cooling system - Cars Info 24

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Tuesday, January 21, 2020

Car engine cooling system



Car engine cooling system


Radiant cooling





 Radiator

panels are heating systems that use heat coming through tubes placed behind the surface of the environment.  It is a name that may be misleading despite its spread, because most heat is transferred - through this device - by convection, and most of it is not transmitted by heat radiation.

 The heat comes through radiation and not by convection, as is the case with heaters (radiator) used in home heating.  Radiator is used to cool the internal parts of the internal combustion engine in vehicles and aircraft (which depend on the internal combustion engine), motorcycles, trains, and any system that relies on the internal combustion engine for its work.  The principle of its action depends on the circulation of a liquid called a coolant, as this fluid passes inside the internal parts of the engine, carrying heat through the principle of heat exchange and then returns to the radiator, which in turn disseminates this heat in the outside air.  The coolant is often water-based and may be used (oil). To circulate this liquid often use a pump that runs between the engine and the radiator. A fan that circulates air through the radiator is also used to cool the liquid.

 Use in vehicles

 Vehicles that use a liquid-cooled internal combustion engine, the radiator connects to the coolant transport channels into the engine by pumping.  Coolant may be just water (in areas where water does not freeze), but mostly a mixture of water and antifreeze is used. The radiator transports heat from the liquid to the surrounding air, dissipating the heat away from the engine. In addition to cooling the engine, the radiator also cools the automatic transmission, the air conditioner, and sometimes, the engine oil.  The radiator is placed in the most exposed places to the air (at the front of the vehicle), as this position is exposed to a large flow of air as a result of moving forward, behind an opening covered with a protection net, for motors located in the middle or behind the vehicle, and in the case of the last engine this position may require tubes Long connection between the radiator and the engine at the time, the atmosphere may be used to draw air from above or from the sides through holes designated for this purpose in long vehicles such as (buses).

 Structure of the radiator

 The radiator consists of two pairs of tanks connected between them by narrow paths called the pulp, which forms a large area compared to its size, the core is made of metal foil pressed to become a (canal) shape, and then welded together, over the years the radiator was made from a brass  Or copper and welded to tanks that are also made of copper or copper. Today, tanks are made of plastic, to reduce manufacturing costs as well as reduce weight, as well as pulp. It is made of aluminum, this modern structure is easy to maintain, from the previous one.


 Coolant pump






 Previously, the coolant was circulated inside the cooling circuit (between the radiator and the engine) by the principle of thermal movement or heat displacement slowly, and when the coolant heats up inside the engine, its density 
decreases and rises, in contrast, the coolant cools inside the radiator, increasing its density so it does not come down, and here it happens  The exchange between the hot liquid coming from the motor from the top and the cold liquid coming from the radiator from the bottom, and so they move in a circle that always lasts slowly but slowly.  This method is suitable for stationary (non-vehicle) motors. This principle in moving the coolant is preferable to increase the vertical distance between the radiator and the engine, to match the movement of the hot rising liquid and the descending cold liquid.  The vehicles are used to move the coolant inside the refrigeration circuit a circulation pump, the movement of which is derived from the engine itself using a gear system or mostly a conveyor belt called a fan belt where if this belt fails, then the entire cooling system is disrupted causing an increase in the engine temperature.


 A radiator that does not use a circulation pump made in 1937 AD relying on the self-movement of the liquid due to heat and cold

 The heater

 Or the cabin heater is a form of the radiator, but in a small form it depends on a group of valves or dispersions, or both, where it interrupts the passage of the liquid to the direction of a miniature radiator inside the cockpit, this miniature radiator is attached to propellers, as it is based on heating the cockpit with a portion of heat  The engine, and its working principle is the same as the principle of the engine radiator, where the core of the mini radiator exchanges heat, which provides adequate warmth to the cockpit.

 Thermostat


 Thermostat valve

 The engine temperature control is carried out through a valve called a thermostat, tightly installed using a wax, blocking the cooling circuit, this valve opens when the engine reaches the ideal temperature needed for optimal operation, when the engine cools too much, the valve closes.  There is a narrow bypass pass that allows the thermostat to test the thermal changes in the sides when the engine starts to gain heat. The thermostat allows the coolant to exit to the circulation pump, and then returns to the engine again, bypassing the stage of passing the radiator. This short circuit, which is limited to turning to and from the engine only, without going through the radiator needed for cooling, allows the engine to quickly acquire heat and is the optimum heat for the engine to operate.  When the engine reaches the ideal temperature, then the thermostat opens, allowing the coolant to transfer to the radiator, so that the engine does not overheat much.

 When the optimum heat is acquired for the engine, the thermostat valve continues to operate, by controlling the flow of the coolant to the radiator, thereby preserving the ideal heat for the engine, under extreme conditions, such as slowly climbing over a plateau in a hot atmosphere, the thermostat valve is in an almost completely open position  Because the engine runs close to its maximum capacity, while the flow of air passing through the radiator is weak (the air flow plays an important role in the radiator's ability to diffuse heat). On the other side, descending from a slope on a cold night under slight pressure from the engine, the valve of the thermostat is approximately in the state of shutdown, because the engine works with little energy while the radiator disperses more heat than what the engine produces, as a result of the high flow of air  In this case, passing more cooling fluid to the radiator causes the engine to cool down below the ideal heat needed to run. Another effect is that the cabin radiator will not produce the heat needed to heat the cabin. The thermostat valve with its constant movement between open and closed, under various conditions, and at various speeds, contributes to maintaining the ideal engine temperature required to obtain the best performance from the engine.

 air flow

 Other factors that affect the engine temperature, including the radiator size, the type of the cooling fan, the radiator size is chosen based on the ideal engine temperature designed for better performance, under various extreme conditions of heat and cold, to which the engine may be exposed (such as climbing up a hill under high engine torque  On a hot day). The velocity of air flow through the radiator plays an important role by dispersing or radiating heat. The speed of the vehicle determines this, as opposed to the effort required by the engine to reach this speed, in a self-regulating process based on self-feedback. In addition, there is a fan driven by the motor itself, which also synchronizes the motor's rotational speed.  The fan attached to the motor often organizes its rotation through a special movement clutch called viscous-drive clutch, which slips and reduces the speed of the fan's rotation at low temperatures. This procedure is economical, as there is no need to waste the energy needed to move the fan in cold climates. In modern vehicles there are other factors that regulate heat rates such as variable speed, rotating radiator fans.  These electric fans are controlled by a thermometer detector consisting of a key (key) or from the vehicle's computer. Also, electric fans have additional advantages, such as giving good air flow and cooling when the engine is at lower power, or in a relatively slow motion, such as what happens during a traffic jam,

 Before the development stage of the fan's clutch and electric fans, the engines were equipped with a simple fan that provides air flow at all times that have many downsides, especially for vehicles that require high cooling capabilities and thus a large radiator, such as commercial vehicles and trucks, which often cool too much.  Under a little effort from the engine in cold times. The appearance of the thermometer detector did not affect anything, since once it is in the open position in the large radiator and with a simple motor fan, it leads to a sharp decrease in temperature. The solution at the time was to provide the radiator with a veil that was partially or completely modified to block the high airflow.  The veil is made in the simplest form of simple materials such as (the fabric and the rubber that the radiator covers). Some vehicles contained a veil that was modified from the cockpit to give the required control.

 Coolant pressure

 The engine's heat equivalent is directly proportional to the internal temperature of the engine. The coolant remains under higher pressure conditions than atmospheric pressure, to increase its boiling point.  The radiator has a pressure-relief valve placed inside the radiator cap. This specific valve pressure varies with vehicle models, but often falls between 9 to 15 psi.

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