CN104895818B - A kind of control method of engine electric-controlled fan, apparatus and system - Google Patents

Abstract

The invention provides a control method, device and system for an engine electronically controlled fan. In this application, when the ECU of the hydraulic retarder detects that the water temperature of the circulating water channel of the retarder body is higher than the preset temperature, and it is necessary to turn on the electronically controlled fan for heat dissipation, A message with negative torque is sent to the engine ECU. The engine ECU integrates the first fan speed of the hydraulic retarder and the other fan speeds, and selects a maximum fan speed to control the electronically controlled fan to the cooling water tank. Due to hydraulic The retarder ECU and the engine ECU share a heat dissipation water tank, and use the maximum fan speed to dissipate heat from the heat dissipation water tank, which can not only meet the heat dissipation requirements of the engine body circulating water channel, but also meet the heat dissipation requirements of the hydraulic retarder body circulating water channel. And only the engine ECU is used for fan control, and there will be no two ECUs to control the electronically controlled fan separately, so there will be no problem of heat dissipation conflict.

Description

A control method, device and system for an engine electronically controlled fan

technical field

The invention relates to the technical field of automation, in particular to a control method, device and system for an engine electronically controlled fan.

Background technique

When the vehicle is running, the water temperature of the hydraulic retarder will exceed the preset temperature, resulting in insufficient braking force of the vehicle. In order to solve the above problems, the hydraulic retarder ECU is used in the prior art to judge whether the water temperature exceeds the preset Set the temperature. When the temperature is higher than the preset temperature, the control relay needs to be closed to start the electric control fan, but the electric control fan is also controlled by the engine ECU. When the water temperature of the engine body circulation channel is too high, the engine ECU also needs to control the relay. Close to activate the electronically controlled fan.

The engine ECU and the hydraulic retarder ECU control the electronically controlled fan at the same time, which is prone to conflicts, so a way is needed to solve the above problems.

Contents of the invention

The invention provides a control method, device and system for an engine electronically controlled fan, which can control the movement of the electronically controlled fan without adding relays and connecting wires, so as to achieve the purpose of heat dissipation and cooling.

In order to achieve the above object, the present invention provides the following technical means:

A method for controlling an electronically controlled fan of an engine, comprising:

Receive a message with negative torque sent by the retarder ECU, the message is sent by the retarder ECU when it detects that the water temperature of the circulating water channel of the retarder body is greater than the preset temperature;

calculating a first fan speed corresponding to the negative torque;

Selecting a maximum fan speed from the first fan speed and other fan speeds, the remaining fan speed being at least one fan speed calculated using other water temperature conditions;

The electronically controlled fan is controlled to run according to the maximum fan speed.

Preferably, the controlling the electronically controlled fan to operate according to the maximum fan speed includes:

When the maximum fan speed is greater than a first wind speed threshold, closing a first relay corresponding to the first wind speed threshold;

When the maximum fan speed is greater than the second wind speed threshold, the second relay corresponding to the second wind speed threshold is closed.

Preferably, the calculating the first fan speed corresponding to the negative torque includes:

When the negative torque is less than the preset torque, the control status bit is 1;

When the status bit is 1, the preset fan speed is used as the first fan speed.

Preferably, the message carrying the negative torque sent by the receiving hydraulic retarder ECU includes:

Receive messages with negative torque sent by the retarder ECU via the CAN bus.

A method for controlling an electronically controlled fan of an engine, comprising:

Detect the water temperature of the circulating water channel of the hydraulic retarder body;

When the water temperature of the hydraulic retarder is higher than the preset temperature, a message carrying negative torque is sent to the engine ECU.

A control device for an electronically controlled fan of an engine, comprising:

The receiving unit is used to receive the message with negative torque sent by the hydraulic retarder ECU, the message is that the hydraulic retarder ECU detects that the water temperature of the circulating water channel of the hydraulic retarder body is greater than the preset temperature sent when

A calculation unit, configured to calculate a first fan speed corresponding to the negative torque; select a maximum fan speed from the first fan speed and other fan speeds, and the remaining fan speed is at least one fan calculated by using other water temperature conditions Rotating speed;

The control unit is used to control the electronically controlled fan to operate according to the maximum fan speed.

Preferably, the control unit includes:

A first control unit, configured to close a first relay corresponding to the first wind speed threshold when the maximum fan speed is greater than a first wind speed threshold;

The second control unit is configured to close a second relay corresponding to the second wind speed threshold when the maximum fan speed is greater than a second wind speed threshold.

A control device for an electronically controlled fan of an engine, comprising:

The detection unit is used to detect the water temperature of the circulating water channel of the hydraulic retarder body;

The sending unit is configured to send a message carrying negative torque to the engine ECU when the water temperature of the hydraulic retarder is greater than a preset temperature.

A control system for an electronically controlled fan of an engine, comprising:

Hydraulic retarder ECU, hydraulic retarder body circulating water channel, engine ECU, engine body circulating water channel and electronically controlled fan;

The hydraulic retarder ECU is connected to the hydraulic retarder, the engine ECU is connected to the engine, the electronically controlled fan is connected to the engine ECU, and the hydraulic retarder ECU is connected to the engine ECU;

The hydraulic retarder ECU is used to detect the water temperature of the circulating water channel of the hydraulic retarder body; when the water temperature of the hydraulic retarder is greater than the preset temperature, send a message carrying negative torque to the engine ECU;

The engine ECU is used to receive a message with a negative torque sent by the retarder ECU, and the message is that the retarder ECU detects that the water temperature of the circulating water channel of the retarder body is higher than the preset value. Sent when the temperature is set; calculate the first fan speed corresponding to the negative torque; select the maximum fan speed from the first fan speed and the remaining fan speeds, and the remaining fan speeds are at least one calculated using other water temperature conditions Fan speed: controlling the electronically controlled fan to run according to the maximum fan speed.

Preferably, the engine ECU is connected to the hydraulic retarder ECU through a CAN bus.

The present invention provides a control method, device and system for an engine electronically controlled fan. The ECU of the hydraulic retarder detects that the water temperature of the circulating water channel of the hydraulic retarder body is higher than the preset temperature, and it is necessary to turn on the electronically controlled fan to carry out When dissipating heat, a message with negative torque is sent to the engine ECU. The engine ECU integrates the wind speed of the first fan of the hydraulic retarder and the wind speed of the other fans, and selects a maximum fan speed to control the electronically controlled fan to the cooling water tank. Since the hydraulic retarder ECU and the engine ECU share a cooling water tank, the maximum fan speed is used to dissipate heat from the cooling water tank, which can not only meet the heat dissipation requirements of the engine body circulating water channel, but also meet the cooling requirements of the hydraulic retarder body circulating water channel , and only the engine ECU is used for water temperature control, there will be no two ECUs to control the electronically controlled fan separately, so there will be no problem of heat dissipation conflict.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a control system for an engine electronically controlled fan disclosed in an embodiment of the present invention;

Fig. 2 is a flow chart of a method for controlling an engine electronically controlled fan disclosed in an embodiment of the present invention;

Fig. 3 is a flow chart of another control method for an engine electronically controlled fan disclosed in an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a control device for an engine electronically controlled fan disclosed in an embodiment of the present invention;

Fig. 5 is a structural schematic diagram of another control device for an electronically controlled fan of an engine disclosed in an embodiment of the present invention;

Fig. 6 is a schematic structural diagram of another control device for an engine electronically controlled fan disclosed in an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Fig. 1, the present invention provides a kind of control system of engine electronically controlled fan, comprising:

① Engine body circulating water channel, ② Engine water temperature sensor, used to monitor engine water temperature, ③ Engine ECU, installed on the engine body, ④ Communication CAN line, ⑤ Hydraulic retarder ECU, installed on the hydraulic retarder On the body of the retarder, ⑥ is the water temperature sensor of the hydraulic retarder, which is used to monitor the water temperature of the hydraulic retarder, ⑦ is the circulating water channel of the hydraulic retarder body; ⑧ is the thermostat, used to control the size of the circulating water, Whether to enter the cooling water tank, ⑨ is the cooling water tank, used for water temperature cooling, ⑩ electric control fan, installed on the engine crankshaft.

It can be seen from Fig. 1 that the circulating water channel of the engine body, the circulating water channel of the hydraulic retarder body and the cooling water tank constitute the water circulation device. When the water temperature of the retarder is too high, it enters the thermostat through the outlet pipe of the hydraulic retarder. When the thermostat determines that the outlet water temperature is higher than the opening temperature, the outlet water of the circulating water channel of the hydraulic retarder body is put into the cooling water tank. , if the thermostat determines that the temperature of the outlet water is lower than the opening temperature, the outlet water of the hydraulic retarder will directly enter the circulation channel of the engine body for recycling.

When the hot water in the cooling water tank is radiated by the electronically controlled fan, the cooled water enters the circulating water channel of the engine body through the water tank outlet pipe of the cooling water tank, and then enters the circulating water channel of the hydraulic retarder body, thereby achieving the circulating water channel of the engine body And the purpose of cooling the circulating water channel of the hydraulic retarder body.

As shown in Figure 2, the present invention provides a control method for an engine electronically controlled fan, including:

Step S101: Receive a message with negative torque sent by the retarder ECU, the message is sent by the retarder ECU when it detects that the water temperature of the circulating water channel of the retarder body is greater than the preset temperature of;

This method is applied to the engine ECU. The engine ECU itself will detect whether the water temperature of the circulating water channel of the engine body exceeds the set temperature. When the temperature exceeds the set temperature, it will control the electric control fan to rotate at a certain speed. The ECU will also calculate the remaining speeds of the electronically controlled fan according to other water temperature control conditions.

In addition, the engine will also receive the message carrying the negative torque sent by the hydraulic retarder ECU, and calculate according to the negative torque to obtain the first fan speed corresponding to the negative torque. The present invention uses the CAN bus between the engine ECU and the hydraulic retarder ECU for message transmission, so that it is not necessary to add a separate wire harness between the engine ECU and the hydraulic retarder ECU, and it will not change the connection between the engine and the hydraulic retarder. The structural relationship of the force retarder ECU is simple and convenient.

Step S102: Calculate the first fan speed corresponding to the negative torque;

There are many ways to calculate the corresponding first fan speed according to the negative torque, and this embodiment provides the following ways:

The first type: When the water temperature of the circulating water channel of the hydraulic retarder body is higher than the preset temperature, a fixed value of negative torque is sent to the engine ECU, and the engine ECU calculates an electronically controlled fan speed based on the fixed negative torque, and the electric motor Control the fan speed as the first fan speed.

The second type: When the water temperature of the circulating water channel of the hydraulic retarder body is higher than the preset temperature, different sizes of negative torque will be sent to the engine ECU according to the water temperature of the hydraulic retarder, and the engine will calculate different sizes of electric torque based on the negative torque. To control the speed of the fan, it can be understood that the higher the water temperature of the circulating water channel of the hydraulic retarder body, the greater the calculated speed of the electronically controlled fan.

The third type: when the water temperature of the circulating water channel of the hydraulic retarder body is greater than the preset temperature, a negative torque is launched to the engine (the negative torque can be a fixed value, or it can vary with the water temperature), when the negative torque When the torque is less than the preset torque, the control status bit is 1; when the status bit is 1, the preset fan speed is used as the first fan speed.

This embodiment only provides three methods for calculating the speed of the first electronically controlled fan. Of course, other methods can be used to calculate the first fan speed corresponding to the negative torque, as long as the first fan speed can reach the speed of the hydraulic retarder body. The circulating water channel can be used for heat dissipation purposes.

Step S103: Selecting the maximum fan speed from the first fan speed and other fan speeds, the remaining fan speed being at least one fan speed calculated using other water temperature conditions;

Since the engine and the hydraulic retarder share a cooling water tank, and the circulating water channel of the engine body is connected with the circulating water channel of the hydraulic retarder body, controlling the electronically controlled fan to dissipate heat from the cooling water tank can not only cool down the circulating water channel of the engine body At the same time, it can cool down the circulating water channel of the hydraulic retarder body. In order to meet the dual requirements of the engine body circulating water channel and the hydraulic retarder body circulating water channel, as well as the requirements of other water temperature control conditions, the first fan speed of the hydraulic retarder ECU, the fan speed of the engine ECU, and the remaining fan speeds Select the maximum fan speed in , and use the maximum fan speed to control the operation of the electronically controlled fan.

The electronically controlled fan operates at the maximum fan speed, so that the cooling water tank can dissipate heat at the maximum cooling speed, thus meeting the dual cooling requirements of the hydraulic retarder ECU and the engine ECU.

Step S104: Control the electronically controlled fan to run according to the maximum fan speed.

There are two relays between the engine ECU and the electronic control fan. The two relays are controlled by the first wind speed threshold and the second wind speed threshold. One relay controls the electric control fan to run at a medium speed, and the other relay controls the electric control fan to run at a high speed. The engine ECU After the maximum fan speed is obtained, it is judged that the maximum fan speed is compared with the first wind speed threshold and the second wind speed threshold, and when the maximum fan speed is greater than the first wind speed threshold, the first relay corresponding to the first wind speed threshold is closed; If the maximum fan speed is greater than the second wind speed threshold, then close the second relay corresponding to the second wind speed threshold.

After the corresponding relay is closed, the electronically controlled fan runs at the corresponding speed. When the maximum fan speed is only greater than the first wind speed threshold, only the first relay is controlled to close, and the electric control fan is controlled to run at a medium speed. When the maximum fan speed is greater than the second wind speed threshold , both the first relay and the second relay are closed, and the electric control fan is controlled to run at a high speed, so as to dissipate heat for the cooling water tank as soon as possible.

As shown in Figure 2, the present invention also provides a control method for an engine electronically controlled fan, which is applied to a hydraulic retarder ECU, including:

Step S201: Detect the water temperature of the circulating water channel of the hydraulic retarder body;

The ECU of the hydraulic retarder continues to use the temperature sensor to collect the water temperature of the circulating water channel of the hydraulic retarder body. The hydraulic retarder body circulates the water channel for heat dissipation, so it sends a message with negative torque to the engine ECU.

When the water temperature of the hydraulic retarder is lower than another set water temperature, it stops sending messages to the engine ECU.

Step S202: When the water temperature of the hydraulic retarder is higher than the preset temperature, send a message carrying negative torque to the engine ECU.

The negative torque is expressed as the fan speed required to cool down the circulating water channel of the hydraulic retarder body. The negative torque can be a specific value set in advance, or a value calculated based on the temperature of the circulating water channel of the hydraulic retarder body. , no matter which method is available, as long as the fan speed calculated from the negative torque can achieve the purpose of cooling the circulating water channel of the hydraulic retarder body.

The subsequent execution process is realized by the engine ECU, and the specific execution process is shown in Figure 1, and will not be repeated here.

As shown in Figure 3, the present invention provides a control device for an engine electronically controlled fan, comprising:

The receiving unit 31 is used to receive a message with a negative torque sent by the retarder ECU. The message is that the retarder ECU detects that the temperature of the circulating water channel of the retarder body is higher than the preset value. It is sent when the temperature is lower than another preset temperature, and the sending is stopped.

The calculation unit 32 is used to calculate the first fan speed corresponding to the negative torque; select the maximum fan speed from the first fan speed and the remaining fan speeds, and the remaining fan speeds are at least one calculated by using other water temperature conditions speed of the fan;

The control unit 33 is configured to control the electronically controlled fan to operate according to the maximum fan speed.

As shown in Figure 4, the control unit 33 includes:

The first control unit 41 is configured to close a first relay corresponding to the first wind speed threshold when the maximum fan speed is greater than the first wind speed threshold;

The second control unit 42 is configured to close a second relay corresponding to the second wind speed threshold when the maximum fan speed is greater than the second wind speed threshold.

As shown in Figure 5, the present invention also provides a control device for an engine electronically controlled fan, including:

The detection unit 51 is used to detect the water temperature of the circulating water channel of the hydraulic retarder body;

The sending unit 52 is configured to send a message carrying negative torque to the engine ECU when the water temperature of the hydraulic retarder is greater than a preset temperature.

The invention provides a control device for an engine electronically controlled fan. In this application, when the hydraulic retarder ECU detects that the water temperature of the circulating water channel of the hydraulic retarder body is higher than the preset temperature, and it is necessary to turn on the electronically controlled fan to dissipate heat, through A message with negative torque is sent to the engine ECU. The engine ECU integrates the first fan speed of the hydraulic retarder and the other fan speeds, and selects a maximum fan speed to control the electronically controlled fan to the cooling water tank. Due to the hydraulic retarder The transmission ECU and the engine ECU share a heat dissipation water tank, and use the maximum fan speed to dissipate heat from the heat dissipation water tank, which can not only meet the heat dissipation requirements of the engine body circulation water channel, but also meet the heat dissipation requirements of the hydraulic retarder body circulation water channel, and only use The engine ECU controls the water temperature, and there will be no two ECUs to control the electronically controlled fan separately, so there will be no problem of heat dissipation conflict.

As shown in Fig. 1, the present invention provides a kind of control system of engine electronically controlled fan, comprising:

Hydraulic retarder ECU ⑤, hydraulic retarder body circulating water channel ⑦, engine ECU ③, engine body circulating water channel ① and electronically controlled fan ⑩;

The hydraulic retarder ECU ⑤ is used to detect the water temperature of the circulating water channel of the hydraulic retarder body; when the hydraulic retarder water temperature is greater than the preset temperature, send a message carrying negative torque to the engine ECU;

The engine ECU ③ is used to receive a message with negative torque sent by the retarder ECU. Sent when the temperature is set; calculate the first fan speed corresponding to the negative torque; select the maximum fan speed from the first fan speed and the remaining fan speeds, and the remaining fan speeds are at least one calculated using other water temperature conditions Fan speed: controlling the electronically controlled fan to run according to the maximum fan speed.

The engine ECU is connected with the hydraulic retarder ECU through a CAN bus.

The present invention provides a control system for the electronically controlled fan of the engine. In this application, when the ECU of the hydraulic retarder detects that the water temperature of the circulating water channel of the hydraulic retarder body is higher than the preset temperature, and it is necessary to turn on the electronically controlled fan for heat dissipation, a The message with negative torque is sent to the engine ECU. The engine ECU integrates the wind speed of the first fan of the hydraulic retarder and the wind speed of the other fans, and selects a maximum fan speed to control the electronically controlled fan to the cooling water tank. Due to the hydraulic retarder The radiator ECU and the engine ECU share a heat dissipation water tank, and use the maximum fan speed to dissipate heat from the heat dissipation water tank, which can not only meet the heat dissipation requirements of the engine body circulation water channel, but also meet the heat dissipation requirements of the hydraulic retarder body circulation water channel, and only use the engine The ECU controls the water temperature, and there will be no two ECUs to control the electronically controlled fans separately, so there will be no problem of heat dissipation conflict.

If the functions described in the method of this embodiment are implemented in the form of software function units and sold or used as independent products, they can be stored in a computing device-readable storage medium. Based on this understanding, the part of the embodiment of the present invention that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions to make a A computing device (which may be a personal computer, a server, a mobile computing device or a network device, etc.) executes all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes. .

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. a kind of control method of engine electric-controlled fan, which is characterized in that apply in Engine ECU, electrical control electric fan is controlled In Engine ECU and Retarder ECU, the method includes：

The message for carrying negative torque that Retarder ECU is sent is received, the message is being detected for Retarder ECU The water temperature of Retarder bulk circulation water channel is more than what is sent during preset temperature；

Calculate the first rotation speed of the fan corresponding with the negative torque；

Maximum rotation speed of the fan is chosen in first rotation speed of the fan and remaining rotation speed of the fan, remaining described rotation speed of the fan is utilizes At least one rotation speed of the fan that other water temperature conditions calculate；

The electrical control electric fan is controlled to be operated according to the maximum rotation speed of the fan；

In ECU when the water temperature for detecting Retarder bulk circulation water channel is not more than preset temperature, controlled by Engine ECU Electrical control electric fan.

2. the method as described in claim 1, which is characterized in that the control electrical control electric fan turns according to the maximum fan Speed operating includes：

When the maximum rotation speed of the fan is more than the first wind speed threshold value, then the first relay corresponding with the first wind speed threshold value is closed Device；

When the maximum rotation speed of the fan is more than the second wind speed threshold value, then the second relay corresponding with the second wind speed threshold value is closed Device.

3. the method as described in claim 1, which is characterized in that described to calculate the first rotation speed of the fan corresponding with the negative torque Including：

When the negative torque is less than predetermined torque, state of a control position is 1；

When the mode bit for 1 using default rotation speed of the fan as first rotation speed of the fan.

4. the method as described in claim 1, which is characterized in that the reception Retarder ECU was sent carries negative twist The message of square includes：

Receive the message for carrying negative torque that Retarder ECU is sent through CAN bus.

5. a kind of control device of engine electric-controlled fan, which is characterized in that be integrated in Engine ECU, electrical control electric fan is controlled In Engine ECU and Retarder ECU, including：

Receiving unit, for receiving the message for carrying negative torque of Retarder ECU transmissions, the message is hydrodynamic retarding What device ECU was sent when the water temperature for detecting Retarder bulk circulation water channel is more than preset temperature；

Computing unit, for calculating the first rotation speed of the fan corresponding with the negative torque；In first rotation speed of the fan and remaining Maximum rotation speed of the fan is chosen in rotation speed of the fan, remaining described rotation speed of the fan is at least one wind calculated using other water temperature conditions Fan rotating speed；

Control unit for the electrical control electric fan to be controlled to be operated according to the maximum rotation speed of the fan, is detecting that fluid power delays in ECU When the water temperature of fast device bulk circulation water channel is not more than preset temperature, electrical control electric fan is controlled by Engine ECU.

6. device as claimed in claim 5, which is characterized in that described control unit includes：

First control unit is more than the first wind speed threshold value for working as the maximum rotation speed of the fan, is then closed and first wind speed Corresponding first relay of threshold value；

Second control unit is more than the second wind speed threshold value for working as the maximum rotation speed of the fan, is then closed and second wind speed Corresponding second relay of threshold value.

7. a kind of control system of engine electric-controlled fan, which is characterized in that including：

Retarder ECU, Retarder bulk circulation water channel, Engine ECU, engine body cyclic water channel and automatically controlled wind Fan；

Retarder ECU is connected with Retarder, and the Engine ECU is connected with engine, the electrical control electric fan and institute It states Engine ECU to be connected, the Retarder ECU is connected with the Engine ECU；

The Retarder ECU, for detecting the water temperature of Retarder bulk circulation water channel；When the Retarder sheet When the water temperature of body circulation water channel is more than preset temperature, the message of negative torque is carried to Engine ECU transmission；

The Engine ECU, for receiving the message for carrying negative torque of Retarder ECU transmissions, the message is liquid What power retarder ECU was sent when the water temperature for detecting Retarder bulk circulation water channel is more than preset temperature；Calculating and institute State corresponding first rotation speed of the fan of negative torque；Maximum fan is chosen in first rotation speed of the fan and remaining rotation speed of the fan to turn Speed, remaining described rotation speed of the fan are at least one rotation speed of the fan calculated using other water temperature conditions；Control the electrical control electric fan It is operated according to the maximum rotation speed of the fan, in ECU in the water temperature for detecting Retarder bulk circulation water channel no more than default During temperature, electrical control electric fan is controlled by Engine ECU.

8. system as claimed in claim 7, which is characterized in that pass through between the Engine ECU and Retarder ECU CAN bus is connected.