PWM fan control circuit and control method thereof

Abstract

The invention relates to the technical field of cooling fans, and discloses a PWM fan control circuit which comprises an ECU and a PWM fan connected with the ECU, and the ECU is connected with a cooling liquid temperature sensor, an inter-cooling temperature sensor, an air conditioner switch, an air conditioner pressure sensor and a DPF inlet temperature sensor. The ECU calculates the required duty ratio of a PWM fan according to the cooling liquid temperature obtained by the cooling liquid temperature sensor, the post-intercooling temperature obtained by the post-intercooling temperature sensor, the air conditioner pressure obtained by the air conditioner pressure sensor and the DPF inlet temperature obtained by the DPF inlet temperature sensor. And taking the maximum value as the duty ratio sent to the PWM fan. The invention further discloses a control method of the PWM fan control circuit. According to the PWM fan control circuit and the control method thereof, accurate control over the rotating speed of the PWM fan is achieved, energy is saved, consumption is reduced, and the heat dissipation effect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation fans, and in particular to a PWM fan control circuit and a control method thereof. Background Art

[0002] PWM fan refers to an adjustable speed fan and a temperature-controlled fan. It is widely used in vehicles. Generally, the fan speed is controlled by the ECU according to the coolant temperature. It is a high-speed or low-speed electronic fan that can achieve high or low-speed operation according to the coolant temperature.

[0003] However, the existing vehicle cooling system is complex, and it is difficult to achieve precise control of the PWM fan by relying solely on the coolant temperature. This results in high energy consumption and poor heat dissipation. Summary of the invention

[0004] The purpose of the present invention is to provide a PWM fan control circuit and a control method thereof to address the deficiencies of the above-mentioned technology, thereby achieving precise control of the PWM fan speed, saving energy and reducing consumption, and having a good heat dissipation effect.

[0005] To achieve the above-mentioned purpose, the PWM fan control circuit involved in the present invention includes an ECU and a PWM fan connected to the ECU, the ECU is connected to a coolant temperature sensor, an intercooler after-temperature sensor, an air-conditioning switch, an air-conditioning pressure sensor and a DPF inlet temperature sensor, and the ECU calculates the required duty cycle of the PWM fan according to the coolant temperature obtained by the coolant temperature sensor, the intercooler after-temperature sensor, the air-conditioning pressure obtained by the air-conditioning pressure sensor and the DPF inlet temperature obtained by the DPF inlet temperature sensor, and takes the maximum value as the duty cycle sent to the PWM fan.

[0006] A control method for a PWM fan control circuit, wherein the ECU calculates the required duty cycle of the PWM fan according to the coolant temperature obtained by the coolant temperature sensor, the intercooler after-temperature obtained by the intercooler after-temperature sensor, the air-conditioning pressure obtained by the air-conditioning pressure sensor, and the DPF inlet temperature obtained by the DPF inlet temperature sensor, and takes the maximum value as the duty cycle sent to the PWM fan.

[0007] Preferably, when the coolant temperature obtained by the coolant temperature sensor reaches t1, the PWM fan starts to run;

[0008] When the coolant temperature is lower than t2, t2<t1, the PWM fan stops running;

[0009] When the coolant temperature is higher than t3, t3>t1, the PWM fan operates at full speed;

[0010] When the coolant temperature is between t1 and t3, the PWM fan is linearly controlled from the lowest speed to the highest speed.

[0011] Preferably, when the intercooler after-temperature obtained by the intercooler after-temperature sensor reaches t4, the PWM fan starts to run;

[0012] When the temperature after cooling is lower than t5, t5<t4, the PWM fan stops running;

[0013] When the temperature after intermediate cooling is higher than t6, t6>t4, the PWM fan operates at full speed;

[0014] When the temperature after intercooling is between t4 and t6, the PWM fan is linearly controlled from the lowest speed to the highest speed.

[0015] Preferably, when the air conditioning switch sends an air conditioning A / C start request signal, the ECU adjusts the speed of the PWM fan according to the air conditioning pressure obtained by the air conditioning pressure sensor;

[0016] When the air conditioning pressure is lower than P1, the PWM fan operates at a low speed;

[0017] When the air conditioning pressure is higher than P2, P2>P1, the PWM fan works at high speed;

[0018] When the air conditioning pressure is between P1 and P2, the PWM fan is infinitely regulated in the low speed gear and high speed gear range;

[0019] When the ECU receives an air-conditioning shutdown request signal and the air-conditioning pressure is lower than P3, P3<P1, and the PWM fan is shut down after a delay of several seconds.

[0020] Preferably, when the DPF inlet temperature obtained by the DPF inlet temperature sensor exceeds t7, the PWM fan is infinitely regulated in speed between a low speed gear and a high speed gear.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. By controlling the PWM fan based on the coolant temperature, the temperature after the intercooler, the air conditioning switch, and the air conditioning pressure, the PWM fan is precisely controlled, which plays a role in energy saving and consumption reduction;

[0023] 2. When the air-to-gas ratio is low or high, turn off the PWM fan to reduce noise;

[0024] 3. Connect the DPF inlet temperature to the PWM fan control and turn on the PWM fan in time to prevent the customer from driving at a low gear, low speed and high load during driving regeneration conditions. At this time, heat will accumulate. If the PWM fan cannot be activated and turned on, overheating problems may occur. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific embodiments.

[0026] A PWM fan control circuit comprises an ECU and a PWM fan connected to the ECU, wherein the ECU is connected to a coolant temperature sensor, an intercooler after-temperature sensor, an air conditioner switch, an air conditioner pressure sensor and a DPF inlet temperature sensor, and the ECU calculates a required duty cycle of the PWM fan according to the coolant temperature obtained by the coolant temperature sensor, the intercooler after-temperature sensor, the air conditioner pressure obtained by the air conditioner pressure sensor and the DPF inlet temperature obtained by the DPF inlet temperature sensor, and takes the maximum value as the duty cycle sent to the PWM fan.

[0027] A control method for a PWM fan control circuit, wherein an ECU calculates the required duty cycle of the PWM fan according to the coolant temperature obtained by a coolant temperature sensor, the intercooler after-temperature obtained by an intercooler after-temperature sensor, the air-conditioning pressure obtained by an air-conditioning pressure sensor, and the DPF inlet temperature obtained by a DPF inlet temperature sensor, and takes the maximum value as the duty cycle sent to the PWM fan.

[0028] In this embodiment, when the coolant temperature obtained by the coolant temperature sensor reaches t1 = 90°C, the PWM fan starts to run, and at this time, the duty cycle is 15%;

[0029] When the coolant temperature is lower than t2=88°C, t2<t1, the PWM fan stops running, and the duty cycle is 5%;

[0030] When the coolant temperature is higher than t3 = 100°C, t3>t1, the PWM fan works at full speed with a duty cycle of 84%;

[0031] When the coolant temperature is between t1 and t3, the PWM fan is linearly controlled from the lowest speed to the highest speed, and the duty cycle is 15% to 84%.

[0032] When the intercooler after-temperature sensor reaches t4 = 50°C, the PWM fan starts running with a duty cycle of 15%;

[0033] When the temperature after cooling is lower than t5 = 47 ° C, t5 < t4, the PWM fan stops running with a duty cycle of 5%;

[0034] When the temperature after cooling is higher than t6 = 65 ° C, t6> t4, the PWM fan works at full speed with a duty cycle of 84%;

[0035] When the temperature after the intermediate cooling is between t4 and t6, the PWM fan is linearly controlled from the lowest speed to the highest speed, and the duty cycle is 15% to 84%.

[0036] When the air conditioning switch sends the air conditioning A / C on request signal, the ECU adjusts the speed of the PWM fan according to the air conditioning pressure obtained by the air conditioning pressure sensor;

[0037] When the air conditioning pressure is lower than P1 = (1.37 ± 0.1) MPa, the PWM fan works at low speed, and the low speed output is 30% duty cycle;

[0038] When the air conditioning pressure is higher than P2 = (1.77 ± 0.1) MPa, P2>P1, the PWM fan works at high speed, and the high speed output has a duty cycle of 84%;

[0039] When the air conditioning pressure is between P1 and P2, the PWM fan has stepless speed regulation between low speed and high speed, and the duty cycle range is 30% to 84%.

[0040] When the ECU receives the air conditioning shutdown signal and the air conditioning pressure is lower than P3 = (0.196 ± 0.02) MPa, P3 < P1, and the PWM fan is shut down after a delay of 10 seconds.

[0041] Finally, when the DPF inlet temperature obtained by the DPF inlet temperature sensor exceeds t7 = 550°C, the PWM fan is infinitely regulated in the low-speed gear and high-speed gear range, and the duty cycle range is 30% to 84%.

[0042] The PWM fan control circuit and control method of the present invention realizes precise control of the PWM fan by controlling the PWM fan based on the coolant temperature, the temperature after the intercooler, the air-conditioning switch and the air-conditioning pressure, thereby achieving energy saving and consumption reduction. When the air ratio is at a low or high level, the PWM fan is turned off to reduce noise. The DPF inlet temperature is connected to the PWM fan control to turn on the PWM fan in time, thereby preventing the customer from driving at a low gear, low speed and high load during driving regeneration conditions, at which time heat accumulation occurs. If the PWM fan cannot be activated and turned on, overheating problems are likely to occur.

Claims

1. A PWM fan control circuit, comprising an ECU and a PWM fan connected to the ECU, characterized in that: The ECU is connected to a coolant temperature sensor, an intercooler after-temperature sensor, an air-conditioning switch, an air-conditioning pressure sensor and a DPF inlet temperature sensor. The ECU calculates the required duty cycle of the PWM fan according to the coolant temperature obtained by the coolant temperature sensor, the intercooler after-temperature sensor, the air-conditioning pressure obtained by the air-conditioning pressure sensor and the DPF inlet temperature obtained by the DPF inlet temperature sensor, and takes the maximum value as the duty cycle sent to the PWM fan.

2. A control method for the PWM fan control circuit as claimed in claim 1, characterized in that: The ECU calculates the required duty cycle of the PWM fan according to the coolant temperature obtained by the coolant temperature sensor, the intercooler after-temperature obtained by the intercooler after-temperature sensor, the air-conditioning pressure obtained by the air-conditioning pressure sensor, and the DPF inlet temperature obtained by the DPF inlet temperature sensor, and takes the maximum value as the duty cycle sent to the PWM fan.

3. The control method of the PWM fan control circuit as claimed in claim 2, characterized in that: When the coolant temperature obtained by the coolant temperature sensor reaches t1, the PWM fan starts to run; When the coolant temperature is lower than t2, t2<t1, the PWM fan stops running; When the coolant temperature is higher than t3, t3>t1, the PWM fan operates at full speed; When the coolant temperature is between t1 and t3, the PWM fan is linearly controlled from the lowest speed to the highest speed.

4. The control method of the PWM fan control circuit as claimed in claim 2, characterized in that: When the intercooler after-temperature obtained by the intercooler after-temperature sensor reaches t4, the PWM fan starts to run; When the temperature after cooling is lower than t5, t5<t4, the PWM fan stops running; When the temperature after intermediate cooling is higher than t6, t6>t4, the PWM fan operates at full speed; When the temperature after intercooling is between t4 and t6, the PWM fan is linearly controlled from the lowest speed to the highest speed.

5. The control method of the PWM fan control circuit as claimed in claim 2, characterized in that: When the air conditioning switch sends an air conditioning A / C start request signal, the ECU adjusts the speed of the PWM fan according to the air conditioning pressure obtained by the air conditioning pressure sensor; When the air conditioning pressure is lower than P1, the PWM fan operates at a low speed; When the air conditioning pressure is higher than P2, P2>P1, the PWM fan works at high speed; When the air conditioning pressure is between P1 and P2, the PWM fan is infinitely regulated in the low speed gear and high speed gear range; When the ECU receives an air-conditioning shutdown request signal and the air-conditioning pressure is lower than P3, P3<P1, and the PWM fan is shut down after a delay of several seconds.

6. The control method of the PWM fan control circuit as claimed in claim 2, characterized in that: When the DPF inlet temperature obtained by the DPF inlet temperature sensor exceeds t7, the PWM fan is steplessly regulated in the low-speed gear and high-speed gear range.