“borei-k”, “borei-kv” - a unit for smooth control of a car radiator fan (bu evso) with switching via the “negative” wire. Electronically controlled engine cooling system Engine cooling fan speed control

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 standard car 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.
	Borey-A	This is a version with a connector for connecting wires. The connectors are located inside the housing 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.
	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. Recommended for internal combustion engines over 3 liters. "Borey-KV4" commutes the "ground". Model power 520W. There is a custom version for 24 Volt.
	Borey-AV4	This powerful version is on another page. Model 2019 "Borey-AV4" commutes "plus". Model power 520W. Recommended for internal combustion engines over 3 liters. 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 - the 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 switching 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 an additional fan for the 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 temperature stabilization;
• 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;
• redundancy (the standard cooling system remains as a backup).
• To control the unit, no mechanical buttons are used; the control is non-contact, magnetic.

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 the vehicle's on-board network.

Operating principle of the fan control unit

There is no “discovery of America” here. While there is no gigantic effect, it is generally 15-30% compared to a classic fan control system.

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 ensure cooling of the internal combustion engine in the most severe mode (maximum power mode). 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; more power will not be beneficial ().

In general, exactly efficient fan control algorithms 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. Cars from different countries use different connectors, but the internal type of contact is almost always the same (size 6.3mm), including Russian-made Bosch fans, as well as Chevy Niva and Kalina fans.

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"

This is a powerful, newer model, it was released in 2018, and 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.

The increased power required major changes to the internal board. If previous versions used automated installation of power elements (first photo below), then this model requires their 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.

I decided to talk about one of my long-standing microcontroller developments (2006), made for smooth control of the electric cooling fan of engines of front-wheel drive VAZ models.

It must be said that at that time there were already a lot of different solutions - from purely analog to microcontroller-based, performing the desired function with varying degrees of perfection. One of them was a fan controller from the Silych company (what now looks like this), famous among those interested in its automatic ignition timing regulator, which programmatically detects engine detonation knocks. I followed the forum of the manufacturer of these devices for some time, trying to determine what turned out well in the device, and some - not so much, and as a result I decided to develop my own.

As planned, in contrast to existing solutions at that time, the new device was supposed to a) be placed in the housing of a regular automotive relay;
b) do not require changes in the standard vehicle wiring; c) have no adjustment elements; d) operate reliably and stably under real operating conditions.

The history of the appearance of the device and the operating algorithm of the first version were discussed - for those who do not want to click, I will describe the key things online:

1. The operating algorithm of the device was assumed to be the following: the voltage on the standard engine temperature sensor was measured; upon reaching the lower threshold temperature, the fan began to spin at minimum speed, and if it increased further, it linearly increased the rotation speed up to 100% at the moment when, according to the ECM (engine control controller), it was time to turn on the fan at full power.
That is, the temperature value corresponding to 100% switching on could be obtained when the device was turned on for the first time, because it has an input corresponding to the output of the standard relay winding.
The lower threshold in the first version had to be set somehow, thus drawing a linear control characteristic through two points.

0. At currents of the order of 20A, it is obvious that PWM is used for smooth regulation, and a powerful field switch is used as a key element.

1. Placing the device in a conventional relay housing means there is virtually no heat sink. And this, in turn, imposes strict requirements on the power dissipated by the key element in static (channel resistance) and dynamic (switching speed) modes - based on the thermal resistance of the crystal-case, it should not exceed 1 W under any conditions

2. The solution to point 1 can be either the use of a field driver or operation at a low PWM frequency.
Unlike analogues, for reasons of compactness and noise immunity, an option with a low PWM frequency was chosen - only 200 Hz.

4. Programming the device's activation threshold should either be very simple or completely automatic. Initially, the device was equipped with a reed switch, by bringing a magnet to it through the housing, the lower threshold was programmed (the value, of course, was stored in the EEPROM). The upper threshold was set itself at the moment of the first pulse from the ECM.
Subsequently, I came up with and implemented an algorithm for fully automatic setting of thresholds, based on finding the thermostable point of the engine (thermostat response point) in the absence of saturation in radiator-to-air heat transfer.

5. The device must provide diagnostics to the user. For this, an LED was added that blinked two bytes in binary code - the current ADC code and the word of status flags.

The device was assembled partly by overhead mounting directly on the terminals of the former relay, partly on a printed circuit board that had turned up from somewhere.
The power MOSFET drain output was soldered directly to the relay output lamella, which increased the power dissipation margin. The device worked without glitches on a VAZ-2112 from 2006 to 2010, when I removed it before selling it, and was used not only in the cold climate of St. Petersburg, but also on the Crimean mountain roads (and even on a car in a supercharged version - it was standing on my inlet drive compressor), despite the installation of the prototype level and the controller in the socket.

Here is the original diagram (drew only on paper):

And this is a view of the device from the inside:

The device was repeated by several people, one of them (off-roader Gennady Olomutsky from Kyiv) used it on a UAZ, drawing a circuit in sPlan and laying out a printed circuit board - in his version it looks like this:

But here is a piece from correspondence with one of those who repeated this device - in it the algorithm was written out in detail for the first time (!) - before that he wrote directly from the brain into assembler:
Now the idea and implementation of the autoinstallation algorithm itself (all steps below correspond to unspecified thresholds):

1. We are waiting for the signal to turn on the fan from the ECM (or from the temperature sensor in the radiator in Gennady’s version)
2. We remember the temperature at the moment the signal appears as T1 (we actually remember the ADC channel code for digitizing the sensor signal - let's call it C1)
3. Turn on the fan at 100%. Set the flag “autoinstallation mode is active (bit 3)”
4. After 3 seconds, we read the ADC code (let's call it C1"). This action is necessary in order to determine the amount of temperature compensation due to the influence of the current flowing through the fan and the resulting voltage drop in the measuring circuit on the digitized temperature value In reality, in 3 seconds the motor does not have time to cool down, but the fan starts and reaches the rated current.
5. Calculate the ADC correction for 100% fan power (let's call it K100 = C1 - C1"). Remember K100.
6. We are waiting for the signal to turn on the fan to be removed from the ECM (or the sensor in the radiator is turned off).
7. Smoothly reduce the power from 75% to 12% by about 1.5% per second.
8. Turn off the fan and wait 60 seconds.
9. We remember the temperature as T2 (ADC code C2).
10. We adjust the lower threshold (increase by 1/8 of the difference between the upper and lower) so that it is above the thermostable point of the thermostat. T2 = T2 + (T1 - T2) / 8. In ADC codes this is C2 = C2 - (C2 - C1) / 8, because The voltage at the sensor drops with increasing temperature.
11. Save C1, C2, K100 in the internal EEPROM of the relay.
12. Set the flag “thresholds are set” (bit 5), remove the flag “auto-setting mode is active”, exit the auto-setting mode to the operating mode

The idea of ​​the algorithm is that it blows through the radiator to the thermostable point of the thermostat, but does not blow strongly so as not to cool the engine by directly cooling the block and head. Then the fan turns off and the relay allows the motor to warm up a little - this way we automatically get the point for the fan to start operating.

During auto-installation, the relay receives a signal from the reed switch during steps 7 and 8 - bringing the magnet to the relay at these moments causes a sequence of steps 9, 11, 12. The threshold is not adjusted at step 10).

If during auto-installation some conditions expected by the relay are violated, the “auto-configuration error (bit 4)” flag is set and the relay exits auto-installation mode. In order for the relay to be able to enter this mode again according to the conditions of step 1, it is necessary to turn off and turn on the power of the relay.

Errors are caught like this:
Step 2 - ADC value is out of range (too low or high). The auto-configuration range according to the ADC code is 248..24 (11111000...00011000). In this case, the relay simply does not enter auto-configuration mode without setting the error flag.
Step 4 - within a waiting time of 3 seconds, the removal of the external fan signal is detected.
Step 7 - during a decrease in speed, an active external signal to turn on the fan is detected. Step 8 - while waiting, an active external signal to turn on the fan is detected. Step 11 - the set thresholds are outside the range of 248..24, or the difference C2 - C1< 4 (то есть они слишком близко друг к другу, либо по какой-то причине C2 >C1 - for example, when the fan does not actually work and the temperature continues to rise)

Now working mode:

Calculation of required power (Preq)
1. If the external signal is active - Preq = 100% 2. If inactive, then the current ADC code © and the corresponding temperature T are looked at:
T< T2 (C >C2): Preq = 0%
T > T1 (C< C1): Preq = 100%
T2<= T <= T1 (C2 >= C >= C1): Preq = Pstart + (100% - Pstart) * (C2 - C) / (C2 - C1) where Pstart = initial power (12%)

At the same time, the required power is not immediately supplied to the fan, but goes through a smooth acceleration algorithm and limiting the fan start/stop frequency.
This algorithm only works in operating mode and in the absence of an external turn-on signal:
Let Pcurr be the current fan power
1. If Pcurr > 0 and Preq = 0, or Pcurr = 0 and Preq > 0, that is, it is necessary to start a stopped fan or stop a running fan, then:
- The time the fan has been in this state (started or stopped) is shown. If the time is less than the threshold, the fan state does not change.
- In this case, if Pcurr > Pstart and Preq = 0, then for the remainder of the running state time Pcurr = Pstart is set (that is, the fan rotates at minimum speed) 2. If step 1 is not fulfilled, or the time spent in the state has passed, then:
- If Preq< Pcurr, то устанавливается Pcurr = Preq (то изменение скорости вращения в сторону снижения происходит сразу, как рассчитано новое значение)
- If Preq > Pcurr, then the increase in rotation speed is limited from above by approximately 1.5% per second (except for the case when turning on the fan is requested by an external signal) - that is, if Preq - Pcurr > Pdelta, then Pcurr = Pcurr + Pdelta, otherwise Pcurr = Preq

When calculating power, the average value of the current temperature code C is used (see Calculation of the required power), obtained by the arithmetic average of the last 8 values ​​Cm1, Cm2, Cm3... Cm8. Averaging occurs using the “sliding window” method - that is, placing a new value in a buffer of 8 values ​​pushes out the oldest one and causes recalculation of the arithmetic mean C. The ADC cycle (and recalculation of the average) occurs every 640 ms.
The “raw” (read from the ADC) Cadc value, before entering the counting buffer, participates in the following algorithm:
1. It is checked that Cadc > Cdisc, where Cdics is the max. ADC value for an unconnected measurement pin.
2. If Cadc > Cdisc, then the “sensor not connected (bit 6)” flag is set, the value does not fall into the buffer of the last 8 values, and the average is not recalculated.
3. If Cadc >= Cdisc - that is, the sensor is connected, then Cadc is adjusted by a certain amount depending on the current fan power and the correction value for 100% power (see step 4 of the auto-setting algorithm): Cadc = Cadc + Kcurr, where Kcurr = K100 * (Pcurr / 100%). If Kcurr > 0, then the flag “ADC value adjusted (bit 7)” is set. The correction algorithm works only in operating mode and does not work in autoconfiguration mode.
4. The negative dynamics of Cadc are limited in order to suppress sharp decreases in C due to pulse load in the vehicle power circuits common with the temperature sensor: If C - Cadc > Cdelta, then Cadc = C - Cdelta. The limitation does not work during the first 15 seconds after turning on the ignition, so that the correct values ​​Cm1, Cm2...Cm8 are quickly formed in the value buffer.
5. The power and dynamics corrected Cadc value is pushed into the value buffer for averaging as Cm1..Cm8 depending on the current value of the buffer head pointer (the buffer is cyclic, the head pointer takes values ​​from 1 to 8).

Now about LED diagnostics:

The first byte is the “raw” ADC code (in earlier versions the average C value was displayed here). The second byte is the status word. There is a pause of about 1.5 seconds between the first and second bytes.
There is a pause of 3-4 seconds between indication cycles.
Bytes are displayed bit by bit, starting with the most significant (bit 7, bit 6,... bit 0).
A long flash corresponds to a bit set to “1”, a short flash to “0”.

Explanation of the status word:
Bit 7 - ADC value adjusted based on current fan power
Bit 6 - temperature sensor not connected
Bit 5 - thresholds set
Bit 4 - threshold setting error
Bit 3 - auto-configuration mode active
Bit 2 - internal processor reset due to hang - abnormal situation
Bit 1 - external fan signal active
Bit 0 - purge mode when stopping the engine is active

When I described the algorithm, I was surprised how it was possible to cram it into 1024 words of tiny15 program memory. However, with a creak, it fit! EMNIP, there were only a couple of dozen free cells left. That's the power of assembler :)

Circuit design PWM speed controllerDC motor.

The control unit for the electric fan of the "Borey" cooling system (BU EVSO) or the controller for the "Argest" stove, as a PWM speed controller, consists of:

• microprocessor(PWM signal generation, current and temperature measurement, mode indication);
• power transistor(current switching, actuator element of the PWM speed controller of the electric fan);
• filter (elimination of electromagnetic interference).

The rotation speed of the commutator motor can be adjusted by changing the voltage supplied to it. At a constant voltage value of the power source - the battery, the voltage on the engine can be changed by changing the resistance in the engine circuit, for example, using a rheostat or transistor. However, when controlling powerful drives, this method leads to the release of large thermal power at the resistance (transistor) and a decrease in system efficiency.
You can increase efficiency by applying full voltage to the motor, but for a limited time. If this is done with a high frequency, then by controlling the duration of switching on, you can actually change the average voltage supplied to the motor.

Changing the duration of pulses with a constant repetition period (constant frequency) is called pulse-width modulation ( PWM, in English texts: PWM-Pulse Width Modulation).

When controlling engine speed using pulse width modulation, full power supply is applied to the engine, but the time for which it is applied is controlled. Relatively speaking, the PWM fan speed controller closes the power switch every second for a tenth of a second, if we need 10% of the engine power, if we need 25% of the power, then the PWM speed controller closes the power switch for a quarter of a second, if 50% of the power - then half a second, etc. When we need to spin the engine to full power, the PWM speed controller closes the power switch for a full second, that is, in fact, the power switch does not open at all.
Of course, in reality the microprocessor controls the power switch with a frequency much higher than once per second, but the principle remains the same. At a sufficiently high frequency, the current ripple in the inductive load is smoothed out, and some effective voltage is actually applied to the motor. Let's say, with a supply voltage of 12V and a pulse duration of 50% of the period, exactly the same result is obtained as when a voltage of 6V is applied to the motor.
When operating a car in the urban cycle with high ambient temperatures, when the probability of engine overheating is maximum (especially in traffic jams), the mode of smoothly changing the fan rotation speed within 30-60% using a PWM speed controller is sufficient to limit the temperature of the car engine. The use of the EVSO control unit in the car cooling system eliminates the need to turn on the fan at a power above 60% (especially at full power), thereby ensuring almost complete absence of noise in the car interior, in contrast to the annoying roar of an electric fan working at full capacity in a conventional system car engine cooling.

An engine cooling fan is a special device that provides airflow to the radiator and a heated car engine by constantly and uniformly removing excess heat into the atmosphere.

Engine cooling fan - types of device

The design of this mechanism, which is often called a radiator fan, is quite simple. It provides for one pulley on which four or more blades are placed. In relation to the plane of rotation, they are mounted at a certain angle, due to which the intensity of air injection increases (below we will tell you exactly where the fan blows).

The design also includes a drive. It can be: hydromechanical; mechanical; electric. The hydromechanical type drive is a hydraulic or special viscous coupling. The latter receives the required movement from the crankshaft. Such a coupling partially or completely blocks when the temperature of the silicone compound filling it rises.

The increase in temperature itself is caused by an increase in the load on the vehicle engine, which occurs with an increase in the number of crankshaft revolutions. The fan turns on the moment the clutch locks. But the hydraulic clutch unit turns on when the volume of oil in it changes. This is its fundamental difference from the viscous device.

By mechanical we mean a drive performed by a belt drive from. On modern cars it is practically not used, since significant power of the internal combustion engine is expended to rotate the fan (the engine gives off too much of its power). But the electric drive, on the contrary, is used very often. It consists of two main components - a control system and an electric motor for the engine cooling fan.

The control system monitors the temperature of the car's engine and ensures the functioning of the cooling mechanism. The drive electric motor is connected to the on-board computer. The control circuit of a standard electric drive consists of:

• ECU();
• a temperature sensor that monitors the temperature of the coolant;
• air flow meter;
• a relay (essentially a regulator), upon whose command the fan turns on and off;
• sensor for counting crankshaft revolutions.

The actuator in this case is the electric motor that provides the drive. The principle of operation of the announced circuit is quite simple: sensors transmit messages to the ECU; the electronic unit where the signals arrive processes them; After analyzing the messages, the ECU starts the fan regulator (relay).

Many cars of recent years of production do not have a regulator in their design, the commands of which turn the fan on and off, but a separate control unit. Its use guarantees more economical and truly efficient functioning of the entire cooling system (the unit always knows where the fan is blowing, at what angle it is located, when it is necessary to turn off the device, and so on).

Diagnosis of cooling fan faults

Neither the most innovative electric motor with high power, nor the ultra-reliable control unit or controller is able to protect the cooling system one hundred percent from breakdowns. Considering that a failed cooling fan that blows in the wrong direction or does not rotate at all can cause engine overheating, it is necessary to constantly monitor its normal functioning.

Timely repair of system components will save your car from many troubles, but it is important to correctly determine the cause of the fan failure. In other words, you first need to find a problem where, for example, the crankshaft speed controller or control unit or electric motor does not work. Any driver can diagnose fan malfunctions based on the recommendations below.

The check should begin by dismantling the connector (plug) of the temperature sensor and inspecting it. In cases where the sensor is single, you need to take a small piece of ordinary wire and close the terminals in the plug. If the fan is working properly, the control unit or relay should give a command to turn it on when closed. If the device we are interested in does not turn on during such a test, this means that it requires repair or replacement.

If there is a double temperature sensor, the testing principle changes slightly and is performed in two stages:

1. The red and red-white wires are closed. In this case, the fan should rotate slowly.
2. Red and black wires are connected. The rotation should now speed up significantly.

If rotation is not observed, the fan will have to be removed and a new device installed in its place. If the radiator cooling fan is constantly running (blowing without interruption), there is a possibility that the sensor for its activation has failed. It is not difficult to verify this suspicion. You must turn on the ignition and then remove the wire tip from the sensor.

If the device does not turn off after this, you can safely buy a new regulator (sensor) for turning off the device. Situations where the radiator cooling fan is constantly running are not uncommon, and now you know how to solve this problem. It also makes sense to check the fuse in cases where you doubt the functionality of the mechanism described in the article. This is done like this:

• from the positive terminal of the battery, power is supplied to the red-black or red-white wires in the fan connector;
• From the negative terminal a charge is supplied to the brown wire.

If the regulator or unit does not respond (the device does not turn on), check the temperature sensor wire (all connectors and plugs on it). The cable may need simple repairs (for example, insulating it, replacing the plug). If the problem is not in the wire, then you will have to purchase a new fan, since yours is broken.

Do-it-yourself dismantling, maintenance and repair of a cooling fan

A decent level of cooling of the radiator and engine of the machine is achieved only if the fan is periodically checked for various minor damage and contamination. It is not at all difficult to regularly perform such a check and use a brush to clean the device from dirt and dust.

The principle of dismantling the fan is simple: remove the ground wire from the battery; disconnect all wires without exception that are suitable for the node in question; Unscrew the bolts securing the device. Now you can slightly move the fan shroud and look at its condition. Such an inspection allows you to identify many breakdowns and perform:

• Stripping and replacing wires: their poor contact is often the reason for inadequate fan operation.
• Repairing brushes (or rather replacing them): this element of the system fails more often than others, since the brushes wear out very quickly, collecting all the dirt from the road.
• Elimination of short circuit or breakage of the rotor windings: sometimes they are in working condition, but do not function well due to contaminants accumulated on them. Solving this problem is not at all difficult - just soak a rag in solvents and thoroughly clean the windings (if necessary, you can also use special cleaning brushes).

Sometimes it is necessary to change the electric motor (for example, when the fan does not start when the engine is well warmed up). Unfortunately, this important part of the cooling device cannot be repaired.

Where does the cooling fan blow?

In this article we cannot ignore the question of where the mechanism that interests us blows. This is exactly what users ask experts and fellow car enthusiasts on dozens and hundreds of forums dedicated to vehicle maintenance. In fact, the answer to this is very simple.

The very purpose of the cooling device and the principle of its operation, described above, tells us that it blows exclusively on the engine, sucking in cold air through the radiator.

If in your car the air flow is directed not to the engine, but to the radiator, this only means that the fan was connected incorrectly after maintenance or repair work. Most likely, the terminals were simply mixed up. Install them correctly and never again wonder where the fan should direct the flow of cooled air.

The performance of a modern computer is achieved at a fairly high price - the power supply, processor, and video card often require intensive cooling. Specialized cooling systems are expensive, so several case fans and coolers (radiators with fans attached to them) are usually installed on a home computer.

The result is an effective and inexpensive, but often noisy cooling system. To reduce noise levels (while maintaining efficiency), a fan speed control system is needed. Various exotic cooling systems will not be considered. It is necessary to consider the most common air cooling systems.

To reduce fan noise without reducing cooling efficiency, it is advisable to adhere to the following principles:

1. Large diameter fans work more efficiently than small ones.
2. Maximum cooling efficiency is observed in coolers with heat pipes.
3. Four-pin fans are preferred over three-pin fans.

There can only be two main reasons for excessive fan noise:

1. Poor bearing lubrication. Eliminated by cleaning and new lubricant.
2. The motor is spinning too fast. If it is possible to reduce this speed while maintaining an acceptable level of cooling intensity, then this should be done. The following discusses the most accessible and cheapest ways to control rotation speed.

Methods for controlling fan speed

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First method: switching the BIOS function that regulates fan operation

The functions Q-Fan control, Smart fan control, etc., supported by some motherboards, increase the fan speed when the load increases and decrease when it drops. You need to pay attention to the method of controlling the fan speed using the example of Q-Fan control. It is necessary to perform the following sequence of actions:

1. Enter BIOS. Most often, to do this, you need to press the “Delete” key before booting the computer. If before booting at the bottom of the screen instead of “Press Del to enter Setup” you are prompted to press another key, do so.
2. Open the “Power” section.
3. Go to the line “Hardware Monitor”.
4. Change the value of the CPU Q-Fan control and Chassis Q-Fan Control functions on the right side of the screen to “Enabled”.
5. In the CPU and Chassis Fan Profile lines that appear, select one of three performance levels: enhanced (Perfomans), quiet (Silent) and optimal (Optimal).
6. Press the F10 key to save the selected setting.

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Second method: fan speed control by switching method

Figure 1. Stress distribution on contacts.

For most fans, the nominal voltage is 12 V. As this voltage decreases, the number of revolutions per unit time decreases - the fan rotates more slowly and makes less noise. You can take advantage of this circumstance by switching the fan to several voltage ratings using an ordinary Molex connector.

The voltage distribution on the contacts of this connector is shown in Fig. 1a. It turns out that three different voltage values ​​can be taken from it: 5 V, 7 V and 12 V.

To ensure this method of changing the fan speed you need:

1. Open the case of the de-energized computer and remove the fan connector from its socket. It's easier to unsolder the wires going to the power supply fan from the board or just cut them out.
2. Using a needle or awl, release the corresponding legs (most often the red wire is positive and the black wire is negative) from the connector.
3. Connect the fan wires to the contacts of the Molex connector at the required voltage (see Fig. 1b).

An engine with a nominal rotation speed of 2000 rpm at a voltage of 7 V will produce 1300 rpm per minute, and at a voltage of 5 V - 900 rpm. An engine rated at 3500 rpm - 2200 and 1600 rpm, respectively.

Figure 2. Diagram of serial connection of two identical fans.

A special case of this method is the serial connection of two identical fans with three-pin connectors. They each carry half the operating voltage, and both spin slower and make less noise.

The diagram of such a connection is shown in Fig. 2. The left fan connector is connected to the motherboard as usual.

A jumper is installed on the right connector, which is fixed with electrical tape or tape.

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Third method: adjusting the fan speed by changing the supply current

To limit the fan rotation speed, you can connect permanent or variable resistors in series to its power supply circuit. The latter also allow you to smoothly change the rotation speed. When choosing such a design, you should not forget about its disadvantages:

1. Resistors heat up, wasting electricity and contributing to the heating process of the entire structure.
2. The characteristics of an electric motor in different modes can vary greatly; each of them requires resistors with different parameters.
3. The power dissipation of the resistors must be large enough.

Figure 3. Electronic circuit for speed control.

It is more rational to use an electronic speed control circuit. Its simple version is shown in Fig. 3. This circuit is a stabilizer with the ability to adjust the output voltage. A voltage of 12 V is supplied to the input of the DA1 microcircuit (KR142EN5A). A signal from its own output is supplied to the 8-amplified output by transistor VT1. The level of this signal can be adjusted with variable resistor R2. It is better to use a tuning resistor as R1.

If the load current is no more than 0.2 A (one fan), the KR142EN5A microcircuit can be used without a heat sink. If it is present, the output current can reach a value of 3 A. It is advisable to include a small-capacity ceramic capacitor at the input of the circuit.

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Fourth method: adjusting the fan speed using rheobass

Reobas is an electronic device that allows you to smoothly change the voltage supplied to the fans.

As a result, the speed of their rotation smoothly changes. The easiest way is to purchase a ready-made reobass. Usually inserted into a 5.25" bay. There is perhaps only one drawback: the device is expensive.

The devices described in the previous section are actually reobass, allowing only manual control. In addition, if a resistor is used as a regulator, the engine may not start, since the amount of current at the moment of starting is limited. Ideally, a full-fledged reobass should provide:

1. Uninterrupted engine starting.
2. Rotor speed control not only manually, but also automatically. As the temperature of the cooled device increases, the rotation speed should increase and vice versa.

A relatively simple scheme that meets these conditions is shown in Fig. 4. Having the appropriate skills, it is possible to make it yourself.

The fan supply voltage is changed in pulse mode. Switching is carried out using powerful field-effect transistors, the resistance of the channels in the open state is close to zero. Therefore, starting the engines occurs without difficulty. The highest rotation speed will also not be limited.

The proposed scheme works like this: at the initial moment, the cooler that cools the processor operates at a minimum speed, and when heated to a certain maximum permissible temperature, it switches to the maximum cooling mode. When the processor temperature drops, the reobass again switches the cooler to minimum speed. The remaining fans support manually set mode.

Figure 4. Adjustment diagram using rheobass.

The basis of the unit that controls the operation of computer fans is the integrated timer DA3 and the field-effect transistor VT3. A pulse generator with a pulse repetition rate of 10-15 Hz is assembled on the basis of a timer. The duty cycle of these pulses can be changed using the tuning resistor R5, which is part of the timing RC chain R5-C2. Thanks to this, you can smoothly change the fan rotation speed while maintaining the required current value at the time of start-up.

Capacitor C6 smoothes the pulses, making the motor rotors rotate more softly without making clicks. These fans are connected to the XP2 output.

The basis of a similar processor cooler control unit is the DA2 microcircuit and the VT2 field-effect transistor. The only difference is that when voltage appears at the output of operational amplifier DA1, thanks to diodes VD5 and VD6, it is superimposed on the output voltage of timer DA2. As a result, VT2 opens completely and the cooler fan begins to rotate as quickly as possible.