Automotive radiator of the liquid cooling system

The radiator is one of the key and most important elements of the liquid cooling system. Dissipating heat into the atmosphere becomes the main task, which was diverted from the engine by the coolant. The radiator of the engine cooling system can be considered the most important part of the power unit itself.

We also recommend reading the article, in which the device of the fuel system of the internal combustion engine is considered. From this article you will be able to learn about the main elements, mixture formation and principles of system operation.

Devices, similar to a modern radiator, were installed on the earliest versions of cars with internal combustion engines, since without the specified cooling element, the operation of the power plant becomes simply impossible. This device is directly responsible for maintaining the normal operating temperature of the engine within strictly defined limits. Such protection protects the motor from overheating, which will inevitably put almost any internal combustion engine out of order.

The history of radiator creation

The water cooling system appeared at the dawn of engine building. For the first time, the radiator concept was applied to the first production car called Benz Velo, which ended up on free sale in 1886 year. This idea of ​​the device was further developed by Wilhelm Maybach, who designed a product with honeycombs. The development found application in the design of the Mercedes 35HP model. Over the following decades and to this day, the radiator device has not undergone global changes, remaining almost in the same form, as in Maybach's time.

The first liquid engine cooling systems did not have a water pump (pumps), which forced the coolant (in the very beginning it was just water) forced to circulate in the system. Early developments of the internal combustion engine cooling system relied on the thermosiphon effect.

Thanks to this effect, the coolant entered the radiator. The thermosiphon effect is based on that, that the density of water decreases when heated. Due to this property, heated water is directed upwards. As a result, heated liquid appeared in the device, entering there through the passage through the upper nozzle.

Water cooling took place inside the radiator, the density of the liquid increased again. This led to, that water was falling into the lower part of the radiator, and from there it penetrated back into the engine jacket through the lower pipe. The main disadvantage of systems with the thermosiphon effect was that, that they could not provide adequate cooling against the background of the ever-increasing power of internal combustion engines. Such systems quickly supplanted solutions, which were based on the use of a centrifugal water pump (pumps).

Liquid cooling system radiator

The main task of the element is to remove heat from the power plant into the atmosphere by cooling the liquid, which passes inside the channels. To ensure better heat dissipation, the device is mounted in such a place, where the best blowing by the oncoming air flow during the movement of the car is noted. A typical place of installation in the underhood space is the area behind the radiator grille at the front of the car. It is worth noting, that even in cars with a rear internal combustion engine, the radiator is most often installed in the front. The difference is the laying of longer lines of the engine cooling system.

There are other places for installing the cooling device, but are less common. Cars with a rear-engine layout can have a radiator, which is installed along the side wall. Such a solution can be found on sports cars, which have two cooling radiators at once, located along both walls of the engine compartment. Effective air blowing is realized by using air intakes. The specified air intake is placed in the rear of the machine on the side walls.

Radiator device

and is a device; b - the steam valve is open; c – the air valve is open.

• The radiator has an upper design (1) and lower (7) tanks. These tanks are connected to each other by tubes (5) from brass or aluminum. Plates are attached to these tubes using soldering (6), which increase the area of ​​surface cooling of the element. Through this surface, heat is transferred from the coolant and released into the environment.
• The upper tank has a filler neck for filling with coolant. The neck is covered with a cork (3). There is steam in this cork (11) and air (12) valves.
• The upper tank also has a spigot (2) for, to connect the radiator to the engine cooling jacket. Such a connection is implemented using a rubber hose. In addition, there is a steam outlet tube (4), as well as an electric thermometer sensor (13).
• Lower tank (7) has a nozzle (8) to connect the device to the pump (pump). There is also an additional tap, which is capable of draining the coolant. The radiator is attached to the car frame with special fasteners (9).

The so-called cores (radiator plates) are the main elements of heat exchange. Depending on the type of core, the following types of radiators are distinguished:

1. tubular;
2. lamellar;
3. tubular-ribbon, etc. d.

Radiator tanks can be made of plastic or metal. If you look at the device in more detail, then the main part of the core, essentially, is a set of seamless aluminum or brass tubes. Tubes, connecting the upper and lower nozzles, having walls up to 0,15 millimeters. Liquid, which passes through the core of the cooling radiator, diverges into a large number of microflows. Each such tube is covered with peculiar ribs, which are thin corrugated copper or aluminum tape.

Products made of aluminum have a lower weight compared to other manufacturing materials, but prone to accelerated destruction. The point is, that a number of significant difficulties arise when trying to weld this metal, and also aluminum is poorly resistant to mechanical damage.

In order for the aluminum product to approach the quality of cooling to the brass structure, it must be made large in size and increase the thickness of the element. At the beginning of the automotive era, cellular radiators were actively used. Such a device was made of small sections of brass tubes, which had a pentagonal section. The liquid inside such tubes did not circulate forcibly, and the entire cooling process was carried out using the contact of metal ribs with the counterflow of air.

Let's return to the device of a modern radiator. Steam valve, shown in the figure, is loaded by a special spring (10). The spring has elasticity 1250-2000 p. This allows you to increase the pressure in the cooling radiator and raise the boiling point of the coolant in the liquid cooling system to 110-119°С. This solution ensures a reduction in the volume of coolant in the entire system, which means a parallel decrease in engine mass. At the same time, the required cooling intensity of the power unit is maintained. Another plus is the reduction of losses, which should be understood as the evaporation of the cooling liquid.

The air valve is also spring-loaded, but weaker in resistance. The elasticity of such a spring is on the mark 50-100 p. The task of the air valve is to let air into the device in that case, if coolant condensation occurred after that, how it boiled and was cooled.

In other words, excessive pressure may occur inside the system due to the phenomenon of vaporization. The boiling point of the coolant rises accordingly, at the same time, there is no dependence on atmospheric pressure, since the reset pressure is set by the valve in the cover. This feature of the cooling system is indispensable when driving in mountainous terrain. Due to the reduced atmospheric pressure in the mountains, the coolant boils faster, than under normal conditions. This solution for installing the air valve thus prevents the destruction of the radiator. which can simply be crushed by atmospheric pressure.

Cork, equipped with valves, ensures the opening of the exhaust valve in the event of boiling of the coolant inside the system and the occurrence of excess pressure, which is approximately on the mark 0,5 kg / cm2. The steam is discharged into the steam outlet tube. The intake valve provides air access then, when the pressure inside is below atmospheric pressure (lower 1 kg / cm2), which occurs on the device when cooling the coolant.