Cooling fan unit. Intelligent Engine Cooling Fan Control Relay

On modern car One fan is installed, operating in different speed modes.

Cooling fan control does two things:

preventing motor overheating;
cooling of freon in the condenser.

It is controlled by a control unit located on the fan fittings. The fan, fittings and control unit are one unit. If one of the parts fails, the entire assembly is replaced.

Control unit malfunction

One of the problems with the cooling system is the failure of the cooling fan, which prevents the fan from working and causes overheating of the motor, and when using an air conditioner, overheating of the freon, an increase in pressure, and as a result, damage to the air conditioning system.

If overheating can be noticed from the engine temperature gauge on the dashboard, then overheating of freon can be determined only by indirect signs ( insufficient cooling air).

Controlling the cooling fan does not imply, but it can be repaired. Two weak points This field effect transistors IRF477. They are N-channel transistors with a voltage of 450V and a current of 8.8A. During repairs, they are replaced with IRF640, since 477s are rare on sale and are difficult to find in stores.

Failure of the transistor can also damage the TL494 chip. When repairing this cooling fan control unit, replacing the microcircuit was not required.

Control unit repair

To replace transistors it is necessary to remove part of the compound. This is easy to do by heating it with a soldering station hair dryer.

Next, unscrew the nuts that secure the transistors by drilling two holes in the bottom wall of the case, through which you need to hold the screws with a screwdriver so that the nuts do not turn along with the screws. Next we work with a soldering iron.

To test our design after repair without a machine, we assemble a simulator, although you can short the lilac wire to negative by applying power to the control unit.

After power is applied, the fan should not spin, and when the control wire is shorted to “–” it should spin at medium speed. Using the simulator, it is easy to adjust the rotation speed throughout the entire range.

This device was developed to monitor engine temperature and control the cooling fan clutch and intake manifold heater in a Mercedes 190. The device diagram is shown in the figure and is a regular thermometer on a DS18B20 sensor and a PIC16F628A microcontroller. The device measures the engine temperature, displays it on the screen and, depending on it, turns on the actuators.

* Not indicated on the diagram - VD3 - KS522

The measured engine temperature is displayed in the range from 0 to 99 degrees. If the temperature is below zero degrees, then Lo (low) is displayed on the display, and when it is more than 99 degrees, Hi (high) is displayed. Although the indication limit is 99 degrees, the thermometer still continues to measure temperature. As soon as the temperature reaches 110 degrees (which is considered normal for a Mercedes engine; it does not boil at this temperature), Ot (overheating) will be displayed on the display. And at the RA4 output of the microcontroller, a logical 0 signal appears - an error; this signal can be used to turn on the LED in the cabin, or to control the beeper. The signal to RA4 will be reset only after the ignition is turned off; lowering the engine temperature will no longer have any effect on this signal. At temperatures below 40 degrees, the intake manifold heater will be turned on. Similarly, at a temperature of 89 degrees the cooling fan will be turned on. To reduce the load on the battery, the device has an input that connects to the starter relay. When the starter is turned on, regardless of the engine temperature, the fan and heater are turned off; as soon as the starter is turned off, the fan and heater are turned on according to the measured temperature.

The thermometer-thermostat itself is assembled on printed circuit board and placed in plastic case. The housing is secured with two self-tapping screws directly in the engine compartment. The device must be placed so that it is as far as possible from high-voltage ignition wires and other power wires, as well as as far as possible from hot engine parts. It is highly desirable to use a microcontroller in an extended temperature version - PIC16F628A-E/P, but it is also possible in an industrial version - PIC16F628A-I/P. The board is designed for dual led indicator from Bright LED - BD-A816RD. By and large, an indicator is not needed in this device, but I installed it so that the device would not be completely simple, and also so that you can see the engine temperature right under the hood. The 7805 microcircuit stabilizer must be installed on a small-sized radiator - a strip of aluminum. Electrolytic capacitors you need to choose from frost-resistant specimens.

To make the temperature sensor itself, a brass blank was needed, from which the housing for the DS18B20 sensor was machined. This case is made so that it can easily be screwed into place of one of the standard sensors (unfortunately, they died safely, which is why this device had to be developed). It is advisable to make the case as lightweight as possible in order to reduce its thermal inertia. The sensor must be connected to the microcontroller board with a shielded heat-resistant wire.

Relays can be installed in any convenient location, outside the device body, protective diodes that joke their windings on the board are already installed.

Naturally, this device can be installed in the cabin. Then it will also replace the standard coolant thermometer.

Smart radiator fan control:

Reduced fuel consumption
Increased engine life
The fan operates almost silently

Modifications (types) of "Borea"

There are two types of “Borey” - with switching of either the negative or positive wire to the fan. Accordingly, in “Borey” there will be either the letter “K” (minus) or the letter “A” (plus). All versions are sealed in relation to the board, versions with wires are also sealed in the place where the wires are soldered.

The remaining modifications are related to the presence/absence of soldered wires, the thickness of the power wires (2.5 or 4 sq. mm) and power (360 or 520 W), the type of fan connector (Russian or imported), battery voltage 12V or 24V (trucks).

The “Borey” case is aluminum, 45x45mm or 35x90mm in size, the size is not tied to any type of Borey and can vary from batch to batch. The case serves as a heat sink and is electrically isolated from the board.

You can find out which of the wires to the fan switches the relay of the car’s standard system as follows. With the ignition on, but the engine not running and the fan turned off, you need to use a tester to measure the voltage at any of the fan terminals relative to ground. If the tester shows +12V, then the fan is switched with a ground wire and you need a “Borey-K” or “Borey-KV”. If it shows 0 Volt, then the “positive” wire, respectively, you need “Borey-A” or “Borey-AV”.

	Borey-K	"Borey-K" commutes the "mass". Model power 360W. There will be a custom version for 24 Volt.
	Borey-A	This is a version with a connector for connecting wires. The connectors are located inside the case to prevent dirt from getting into them; a fitting is used to enter the wires. The entire board is sealed with sealant, with the exception of the connector contacts for connecting wires. Wires are not included. The version without wires is convenient because the power wires can be made to the optimal length “on site”. The fitting is designed for wires up to 4 sq. mm, but at the limit 6 sq. mm are possible. "Borey-A" switches the "plus" wire. Model power 360W. There will be no 24V version. This version has been in production since the spring of 2018 and has significant improvements in electronics, implemented functions and programming.
	Borey-KV	This version is on the current page. "Borey-KV" commutes the "ground". Model power 360W. There is a 24V version available.
	Borey-AV	This version is on another page. "Borey-AV" switches the "plus" wire. Model power 360W. Hermetically sealed design "Borea", wires 2.5 sq. mm. included in the kit and soldered directly into the board. The module is completely filled with compound. The version with soldered wires does not imply their lengthening or shortening. Their length, of course, can be changed, but without twisting/soldering/re-crimping this will not work.
	Borey-KV4	This powerful version is on the current page. "Borey-KV" commutes the "ground". Model power 520W. Hermetically sealed design "Borea", wires 4 sq. mm. included in the kit and soldered directly into the board. The module is completely filled with compound. The version with soldered wires does not imply their lengthening or shortening. Their length, of course, can be changed, but without twisting/soldering/re-crimping this will not work.

Purpose of the fan control unit (CU EVSO)

All luxury cars equipped with electric radiator fans of the cooling system also have a smooth control module rotation speed control this fan. This is no coincidence, since such control provides many advantages compared to classic relay control. Smooth Control speed rotation has only one significant drawback- high price. It is precisely in terms of price that our fan control unit gives a huge head start to imported analogues, being in no way inferior to them in other parameters. The history of the creation of "Borey" can be viewed.

“Borey” is designed to change the rotation speed of the electric radiator fan of the cooling system depending on the current temperature of the car engine so that the temperature of the internal combustion engine does not go higher than 1-2 degrees from the set point of turning on the electric fan. Borei copes with this task much better than the standard relay system.

The control unit "Borey" is fan control system , which has advanced functions compared to the standard system.

The EVSO control unit will solve for you the problem of cooling the car engine in the most difficult conditions. "Borey" is much more reliable than a relay.
The EVSO control unit can control a second electric fan or electric pump to increase heat removal from the radiator of the cooling system. Naturally, for the Borey to operate, it requires a fan(s) whose performance is sufficient for the most severe cooling conditions of the car engine.
The EVSO control unit works “in parallel” with the standard fan activation system, without interfering with it. These two systems back up each other, thereby increasing overall reliability.
The EVSO control unit also handles the needs of the car's air conditioner, including blowing out the air conditioner condenser when the air conditioner needs it. This eliminates the need for additional fan for air conditioner.
The EVSO control unit is connected to the vehicle's standard sensor, and there is no need to select or calibrate these sensors. The stabilization temperature is set by the driver himself using a very simple operation (all the details are below).

What vehicles is the EVSO control unit designed for?

Yes, actually, for everyone where there is an electric fan. From "Oka" to "Cherokee", from 0.5 liters of engine capacity to 5-8 liters, including serially installed on AVTOROS all-terrain vehicles. IN powerful cars It makes sense to simply use two electric fans with two Boreis, even where one would do the job. Per liter of volume, installing a Borey on a Cherokee is much cheaper than on an Oka. When replacing a fan with a viscous coupling with an electric fan, it is recommended to use "Borey-K" or "Borey-KV". For powerful machines, the “Borey-KV1-4” version with thick wires with a cross-section of 4 sq. mm is intended. For commercial vehicles and trucks, where the on-board voltage is 24V, the Borei-KV24 version is available.

Advantages:

automatic adjustment of stabilization temperature without driver intervention;
ease of adjustment of stabilization temperature;
monitoring the operation of the cooling system fan using programmed tests;
monitoring the operating parameters of the cooling system when starting the engine;
automatic protection against current overload over 30 A;
automatic protection against short circuit current over 50 A;
easy integration into a standard cooling system;
stabilization of the engine temperature, not the radiator;
high reliability;
reservation ( standard system cooling remains as a backup).
not used to control the unit mechanical buttons, non-contact, magnetic control.

Advantages when using a fan control unit

reduce fuel consumption;
increase the service life (resource) of the car engine;
virtually eliminate noise from fan operation;
reduce the electrical load on on-board network car.

Operating principle of the fan control unit

There is no “discovery of America” here. Just as there is no gigantic effect, it is generally 15-30% in relation to classical system fan control.

When using relay that turns on the electric fan in the classical system, the engine is cooled by 10 degrees, when it is enough to cool it by 1 degree, the extra 9 degrees turn out to be really “extra” work that the Borey does not do in vain. The effect here is, of course, not 9 times, but the gain is double. We already wrote above that the fan must provide cooling of the internal combustion engine in the most severe mode (mode maximum power). When a fan in a traffic jam cools an engine operating at 10% of its power, 30% of the rotation speed is enough for it, from more power there will be no benefit ().

In general, exactly efficient algorithms fan control operation allow you to achieve small savings, but more importantly, allow you to more accurately stabilize the engine temperature. Drivers who have installed Borei usually say: “I installed it and forgot it, but in traffic jams the temperature gauge stays on like a glove.”

Installation

Four sets of wires are available for delivery, differing in the type of fan connector used and polarity (for “Borey-A” and “Borey-K”). The power wires have a cross-section of 2.5 sq. mm.

The first type with a Russian connector is good because if it does not fit the “plastic” to the fan connector, then the contacts can be removed from the plastic case and plugged individually into the fan connector, taking into account the polarity. In cars different countries different connectors are used, but internal type There is almost always one contact (size 6.3mm), including for Bosch fans Russian production, as well as Chevy Niva and Kalina.

The second set of wires with Packard connector 12015987 (picture on the right) fits plastically to most imported fans, including Russian-made Bosch fans, as well as Chevy Niva and Kalina fans. However, it is no longer possible to disassemble such a connector; the contacts inside are specialized and will not fit into another type of connector.

Features of "Borey-KV4"

It's powerful, more new model, it was released in 2018, according to the program and settings it is compatible with Borei-K. This is a model with soldered wires with a cross section of 4 sq. mm. It is mounted similarly to the Borey-KV, and programmed similarly to the Borey-K.

Increased power required major changes internal board. If previous versions used automated installation of power elements (first photo below), then this model requires them manual installation and soldering, which certainly increases its cost.

LED scale to indicate fan speed

The LED scale "Foton-1" shows the current speed (power) of fan rotation. In fact, “Foton-1” is an average voltage meter on the motor. "Foton-3" additionally has a temperature scale showing temperature deviations from the fan activation point.

Not indicated on the diagram - VD3 - KS522

The thermometer-thermostat itself is assembled on a printed circuit board and housed in a plastic case. The housing is secured with two self-tapping screws directly in the engine compartment. The device must be placed so that it is as far as possible from high-voltage ignition wires and other power wires, as well as as far as possible from hot engine parts. It is highly desirable to use a microcontroller in an extended temperature version - PIC16F628A-E/P, but it is also possible in an industrial version - PIC16F628A-I/P. The board is designed for a dual LED indicator from Bright LED - BD-A816RD. By and large, an indicator is not needed in this device, but I installed it so that the device would not be completely simple, and also so that you can see the engine temperature right under the hood. The 7805 microcircuit stabilizer must be installed on a small-sized radiator - a strip of aluminum. Electrolytic capacitors must be selected from frost-resistant specimens.

To make the temperature sensor itself, a brass blank was needed, from which the housing for the DS18B20 sensor was machined. This case is made so that it can easily be screwed into place of one of the standard sensors (unfortunately, they died safely :-), which is why we had to develop this device). It is advisable to make the case as lightweight as possible in order to reduce its thermal inertia. The sensor must be connected to the microcontroller board with a shielded heat-resistant wire.

The cooling system is a mechanism that is designed to cool engine components that are heated during operation. In modern cars it also performs additional functions for cooling the following components:

oils in the lubrication system;
working fluid in an automatic transmission;
exhaust gases in an appropriate recirculation system;
air in the turbocharging system.

In addition, air is heated in air conditioning, ventilation and heating systems.

Types of cooling systems

Based on the cooling method, the systems under consideration can be divided into several types. This:

air (open type);
liquid (closed type);
combined.

In the first case, air flow is used to perform functions. System liquid cooling removes temperature from parts through fluid flow. Combined type provides for the combination of the listed methods to reduce it.

Most often on vehicles a closed type system is installed. This is due to the fact that it is able to provide effective and uniform cooling of the parts of the power unit. In addition, this design produces minimal noise during operation. Therefore, considering this topic, it is worth paying more attention to liquid system cooling.

Cooling system design

It is worth noting that for gasoline and diesel engines, various systems cooling, but their designs are similar. They include a lot of components. The main ones are the coolant radiator, radiator cooling fan, oil cooler, thermostat, centrifugal pump, heat exchanger and expansion tank.

The design of the cooling system also includes a “cooling jacket” of the motor. To perform regulation of mechanisms, they are used special elements management. With their help, you can ensure the optimal level of cooling of the power unit during operation.

Cooling fan and its types

A cooling fan is a device that performs the function of increasing the cooling intensity of the radiator and engine. This is possible thanks to the constant and uniform diversion of tempo from the details into the atmosphere.

Today, there are two workable designs of the device in question: mechanical and electrical. The first type of cooling fan works by transmitting torque from the crankshaft pulley through a V-belt drive.

On modern cars, it is more important to use an electrically driven fan. Its design includes a control system and an electric motor. The temperature sensor readings directly affect the intensity of work of this device. This is the most best option, which has advantages over mechanical analogues, which is why it has gained popularity.

Fans that cool the engine and radiator can be of three types: with viscous coupling, electronically controlled and a thermal switch. These designs have significant differences, so each of them is worth considering in more detail.

Viscous coupling fans

A system based on a viscous coupling is not common. It is equipped with vehicles with a longitudinally mounted power unit, and it is also used on large SUVs used to overcome water obstacles. This is due to the operating principle of such a cooling fan. The viscous coupling is a completely sealed design and is therefore reliably protected from water penetration. Under her influence electrical systems will fail instantly.

The viscous coupling is filled with special silicone oil or gel. It changes its properties when exposed to temperatures. The rotation speed of the device will be reduced or increased depending on the heating level. This cooling fan consists of a sealed housing filled with silicone liquid, as well as drive and driven shaft disk packages. The operating principle is based on the transmission of rotation from the drive to the driven shaft due to disk packs.

Electrically driven fans

The radiator and engine cooling fan with electric drive has more complex design, rather than previous system. In addition, it is more modern, so it is found on many new cars. The device includes an electric motor, a temperature sensor, an electronic control unit, and a cooling fan relay. Most devices have two temperature sensors. One is equipped with a pipe coming out of the radiator. The second sensor is built directly into the thermostat housing, and can also be located in the pipe coming out of the motor. The difference in sensor readings affects the operation of the cooling fan control unit.

Setting the operating mode of the device's electric motor requires an air flow meter, as well as a sensor that monitors the crankshaft speed. The control unit will receive the corresponding signals from all sensors and process them. The cooling fan relay is then activated, which will monitor the rotation speed of the impeller after the system is turned on. Such devices are often installed by car manufacturers nowadays.

Fans with thermal switch

Similar mechanisms were installed on cars before the invention electronic unit. For example, a VAZ cooling fan is also equipped with a thermal switch. This device is responsible for turning on/off the system's electric motor.

Operating principle of cooling fans of this type is as follows: the signal is sent from a temperature sensor, which is installed in the cylinder block housing on a special scale located in the car interior. This indicator and the response of the thermal switch to changes in the temperature of the liquid in the radiator affect the procedure for turning the engine on and off.

If the temperature of the cooler is increased to the maximum, the contacts inside the thermal switch will be closed and connected to the system power circuit. Then current will be supplied to the electric motor, which will cause the fan impeller to rotate. The contacts will open if the temperature drops to the extreme minimum, which guarantees that the device will turn off.

Diagnosis of cooling fan temperature sensor faults

The cooling fan is not protected from damage, even if it has highest quality. Whenever similar problem urgent measures should be taken to eliminate it, since a system malfunction can lead to overheating of the motor. First of all, you should run diagnostics and find out why the cooling fan is not working.

To check a single temperature sensor, you will need to dismantle its connector and short-circuit the terminal in the plug using ordinary wire. The device should turn on. For a double sensor, you must first short-circuit the red and red-white wires, and then the red and black wires. Slow and accelerated rotation (respectively) will be observed. If this does not happen, the cooling fan will need to be repaired or replaced.

Diagnosis of fuse faults

What to do if the cooling fan does not work has become clear. However, what should a motorist do if the system turns on, but is nevertheless inoperative? In such cases, there is no problem with the temperature sensor. If you have such a problem, it is advisable to check the cooling fan fuse, which may be damaged.

To check, you will need to apply power to the red-white wire from the positive terminal of the battery, and from the negative terminal - a charge to the brown wire. In this case, the device should turn on. If this does not happen, you need to check the condition of the plugs, connectors and cables, which are quite easy to replace.

Fan repair and replacement

Motorists often have experience in car repairs, so they can independently diagnose the mechanisms and take measures to eliminate malfunctions. If you lack the appropriate knowledge and skills, you should contact specialists. Repair and replacement of the cooling fan will be carried out efficiently in a specialized center. In addition, this will allow you to maintain the warranty on the car if it has not expired.