A control method and device of an electronic fan

Abstract

The application discloses a control method of an electronic fan, and steps are as follows: fan intelligent control mode in oil-off working condition: when the engine is in the oil-off working condition meeting the judgment condition, the various change conditions of the judgment condition and the battery SOC are recorded; power acceleration fan control limited mode: when the engine starting power output request is close to the limit, all the judgment conditions are met, the fan request electric power is controlled, and the knock preset coefficient is optimized; normal working mode: after the high-speed fan opening switching to the low-speed fan opening process or within the preset time after the high-speed fan opening switching to the low-speed fan opening process, the preset coefficient is adjusted, the power is turned off, the storage is updated, and the fan opening scheme is set according to the updated preset value. The application further discloses a control device of the electronic fan. According to different control modes set under different working conditions, the motor is controlled from a more reasonable angle, and the application can be widely applied in the engine control field.

Description

Technical Field

[0001] This invention relates to the field of engine control, and in particular to a control method and apparatus for an electronic fan. Background Technology

[0002] During normal vehicle operation, the engine coolant temperature needs to be maintained within a suitable range to keep the engine's power, economy, and emissions at optimal levels. When the engine coolant temperature is too high, active cooling of the engine is required. This is achieved by controlling the thermal management module of the electronic control system and the fan to cool the engine while it is running. However, as an electrical load, the fan consumes battery power when it is turned on.

[0003] In light of this, some manufacturers have increased their R&D efforts in this area. For example, a patent application with publication number CN114017174A, entitled "A Control Method and Device for a Fan in an Engine Cooling System," attempts to control the fan based on the water temperature difference. However, this solution does not consider dynamic control of the real-time performance of the cooling system, nor does it consider sampling different control modes from the perspectives of vehicle economy and power under different operating conditions.

[0004] In light of this situation, one manufacturer has introduced another invention, CN111350580A, entitled "An Engine Cooling System and an Engine Cooling Control Method," which directly compares the target temperature and the actual temperature. Based on the magnitude of these two temperatures, it classifies the system into only two operating conditions: when the actual temperature reaches the first preset target temperature and is greater than the second preset target temperature, the control module controls the electronic thermostat to open the first water circuit connected to the radiator until the actual temperature drops to the second preset target temperature; when the actual temperature is less than the second preset target temperature, the control module controls the electronic thermostat to close until the actual temperature reaches the first preset target temperature. However, this introduces the problem that the entire cooling control system also includes a heater and an oil changer, and it does not consider different control modes based on factors such as vehicle economy and power under different operating conditions. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a control method and device for an electronic fan, which sets different control modes according to different working conditions, thereby controlling the motor more reasonably.

[0006] This invention provides a control method for an electronic fan, employing three control modes for various operating conditions. The method includes the following steps: Intelligent fan control mode under fuel cut-off conditions: When the engine is in a fuel cut-off condition that meets certain criteria, the fan operating time is not less than the fan operating time set in the intelligent fan control mode for fuel cut-off conditions. The battery SOC (State of Charge) at the time the criteria are met is recorded. Start The system monitors various changes in battery SOC within a certain time period before the fan starts during the judgment process, and only one of these conditions is triggered each time the fuel cut-off condition occurs; Power acceleration fan control limited mode: When the engine's starting power output request approaches its limit, the fan's power is limited. At the same time, based on meeting all judgment conditions, the fan's requested power is controlled. The rate of change of the fan's requested power is determined by the difference between the actual water temperature and the target water temperature, and the ratio of the engine's requested arc torque to the maximum torque. The knock preset coefficient is optimized based on the knock occurrence situation; Normal operation mode: The fan's requested power is determined based on the difference between the actual water temperature and the target water temperature, and the actual water temperature. If the rate of change of water temperature exceeds a preset value within a preset time period after the high-speed fan starts switching to the low-speed fan, the preset coefficient is adjusted and stored after power-down. The updated preset coefficient is used to determine whether the fan should start at high speed / low speed, and the fan start scheme is set according to the relationship between the updated preset coefficient and the updated preset value.

[0007] In the above technical solution, the specific process of the intelligent fan control mode under fuel cut-off conditions is as follows: Fuel cut-off condition judgment conditions: including engine fuel cut-off request conditions, engine actual water temperature and target water temperature difference conditions, fan status conditions, engine speed closed-loop control conditions, vehicle headlight status conditions, and air conditioning status conditions; Fan start-up time: the default fan start-up time T1 in the intelligent fan control mode under fuel cut-off conditions is set to a fixed value, and the maximum value of this default fan start-up time T1 and the fan start-up time requested by other functions is taken as the final fan start-up duration; Battery SOC change: the battery SOC at the moment when all 6 fuel cut-off condition judgment conditions are met is recorded, i.e., SOC Start The change in battery SOC within the time T2 before the fan starts during the process of satisfying the above 6 fuel cut-off conditions, i.e., reading the maximum battery SOC value. Max and the minimum SOC of the battery Min And the battery SOC at time T2 before the fan turns on: SOC T2 .

[0008] In the above technical solution, the specific conditions of the fuel cut-off condition judgment sub-step are as follows: Engine fuel cut-off request: Engine fuel cut-off request; Difference between actual engine coolant temperature and target coolant temperature: The difference between actual engine coolant temperature and target coolant temperature exceeds the preset coolant temperature Q1; Fan status: Fan is on; Engine speed closed-loop control condition: Not in engine speed closed-loop control condition; Vehicle headlight status: Vehicle headlights are not on; Air conditioning status: Air conditioning is not on.

[0009] In the above technical solution, the specific process of the battery SOC change sub-step is as follows: First default start time: if SOC Start Too low, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the first preset value, then the default fan start time will be updated to T1' = T2 + (T1 - T2) * 0.8, but not less than 0.2 times T1; the second default start time: if the SOC Start Too low, and SOC Start -SOC T2 If the second preset value is exceeded, the default fan start time will be updated to T1' = T2 + (T1 - T2) * 0.5, but not less than 0.2 times T1; the third default start time: if the SOC Start Too high, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the third preset value, then the default fan start time will be updated to T1' = T2 + (T1 - T2) * 1.2, but not exceeding twice T1; the fourth default start time: if the SOC Start Too high, and SOC Start -SOC T2 If the default fan start time does not exceed the fourth preset value, then update the default fan start time to T1' = T2 + (T1 - T2) * 1.5, but not exceeding twice T1; Fifth default start time: if the SOC is normal, and the SOC Start -SOC T2 If the fifth preset value is exceeded, the default fan start time will be updated to T1' = T2 + (T1 - T2) * 0.2, but not less than 0.2 times T1; the sixth default start time: if the SOC Start Normal, and SOC Start -SOC T2 If the default fan start time does not exceed the sixth preset value, then update the default fan start time to T1' = T2 + (T1 - T2) * 1.25, but not exceeding twice T1; The seventh default start time: if the SOC... StartNormal, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the seventh preset value, then the default fan start time is T1' = T1; the final fan start time is: the maximum value of the above default times T1' and the fan start time requested by other functions is taken as the final fan start time. Each oil cut-off condition will only trigger one of the conditions between the first default start time and the seventh default start time.

[0010] In the above technical solution, the specific process of the power acceleration fan control limited mode step is as follows: Starting judgment condition: Engine request torque condition: Engine request torque is close to the maximum torque currently provided by the engine; Battery SOC condition: Battery SOC is low; Accelerator pedal opening condition: Accelerator pedal opening is large enough; Air conditioning status condition: Air conditioning is on; Vehicle speed range condition: Vehicle speed is within a very low range; Control fan request power: First, control fan request power is 0, i.e., the fan is not turned on; then, if the vehicle speed increases beyond a preset value and then no longer decreases, the vehicle... If the speed increases beyond the preset vehicle speed, the fan's requested electric power change rate will be gradually increased. The fan's requested electric power change rate is determined by the difference between the actual and target water temperatures and the ratio of the engine's requested firing torque to the maximum torque. The larger the water temperature difference and the smaller the torque ratio, the greater the fan's requested electric power. Optimize the knock preset coefficient: If the difference between the maximum knock delay ignition angle requested and the actual knock delay ignition angle is within the preset range after knock occurs, or if knock occurs in this operating mode and the difference between the maximum knock delay ignition angle requested and the actual knock delay ignition angle does not exceed the knock preset value, the knock preset coefficient k will be adjusted for various situations.

[0011] In the above technical solution, the specific process of the optimized knock preset coefficient sub-step is as follows: First knock preset coefficient k adjustment: If knock occurs in this working mode, and the difference between the knock request for the maximum ignition angle and the actual knock delay ignition angle is within a preset range, then the knock preset coefficient k in the power acceleration fan control limited mode is 1.2 times the original value. At this time, the updated knock preset coefficient k is changed without powering down and stored; Second knock preset coefficient k adjustment: If knock occurs in this working mode, and the difference between the knock request for the maximum ignition angle and the actual knock delay ignition angle does not exceed the knock preset value, then the knock preset coefficient k in the power acceleration fan control limited mode is 1.5 times the original value. At this time, the updated knock preset coefficient k is changed and then powered down and stored. Then, the updated knock preset coefficient k is used next time to determine whether to enter the power acceleration fan control limited mode.

[0012] In the above technical solution, the specific process of the normal working mode steps is as follows: Fan power request determination condition: The fan power request is determined based on the actual water temperature and the target water temperature difference and the actual water temperature; Preset coefficient adjustment: If the water temperature change rate exceeds a preset value within a preset time after the high-speed fan switches to low-speed fan, the preset coefficient is adjusted according to four cases to change the actual water temperature and the fan power request under the water temperature difference at the time of fan state switching; Preset coefficient update: Various preset coefficients are stored and obtained after power-down. The updated preset coefficient is used to determine whether the fan is turned on at high speed / low speed, and the fan is turned on at high speed, low speed, or off according to the relationship between the updated preset coefficient and the updated preset value A and the updated preset value B.

[0013] In the above technical solution, the specific process of the preset coefficient adjustment sub-step is as follows: First type of preset coefficient setting: If, after the high-speed fan switches to the low-speed fan, the rate of change of water temperature within the first preset time T3 exceeds the first preset value r1 and the total duration exceeds the first preset time threshold T31, then the actual water temperature and the fan's requested power under the water temperature difference at the time of fan state switching are increased, and the first preset coefficient R11 is increased; similarly, if, after the high-speed fan switches to the low-speed fan, the rate of change of water temperature within the first preset time T3 exceeds the second preset value r2 and the total duration exceeds the second preset time threshold T32, then the actual water temperature and the fan's requested power under the water temperature difference at the time of fan state switching are reduced. The rate of change of water temperature within the second preset time T4 after the low-speed fan switches to the high-speed fan exceeds the third preset value r3 and the total duration exceeds the third preset time threshold T41, then the actual water temperature and the fan power requested by the fan under the water temperature difference at the time of fan state switching are increased, and the third preset coefficient R12 is increased; similarly, if the rate of change of water temperature within the second preset time T4 after the high-speed fan switches to the low-speed fan exceeds the fourth preset value r4 and the total duration exceeds the fourth preset time threshold T42, then the actual water temperature and the fan power under the water temperature difference at the time of fan state switching are reduced, and the fourth preset coefficient R22 is reduced.

[0014] In the above technical solution, the specific process of the preset coefficient update sub-step is as follows: the first preset coefficient R11, the second preset coefficient R21, the third preset coefficient R12, and the fourth preset coefficient R22 are all stored after power-down. The updated preset coefficients are then used to determine whether the fan is turned on at high speed or low speed. If the fan's requested power multiplied by the updated preset coefficient is greater than the preset value A, then the high-speed fan is turned on. If the fan's requested power multiplied by the updated preset coefficient is not greater than the preset value A, but greater than the preset value B, then the low-speed fan is turned on. If the fan's requested power multiplied by the updated preset coefficient is less than the preset value B, then the fan is turned off.

[0015] The present invention also provides a control device for an electronic fan, having a computer program that can execute a control method for the electronic fan.

[0016] The electronic fan control method and device of the present invention have the following beneficial effects:

[0017] Different control modes are set according to different working conditions, so as to control the motor more reasonably, which not only meets the needs of extreme power, but also controls the fan more reasonably and intelligently. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall flow of the electronic fan control method of the present invention;

[0019] Figure 2 This is a flowchart illustrating the steps of the electronic fan control method of the present invention for interrupting the intelligent control mode of the fan in oil operation condition;

[0020] Figure 3 This is a flowchart illustrating the steps of the power acceleration fan control restricted mode in the electronic fan control method of the present invention;

[0021] Figure 4 This is a flowchart illustrating the normal operating mode steps in the electronic fan control method of the present invention.

[0022] Figure 5 This is a schematic diagram of the control device for the electronic fan of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but these embodiments should not be construed as limiting the present invention.

[0024] The purpose of this invention is to propose a control scheme for an electronic fan.

[0025] A typical engine cooling system includes an engine outlet temperature sensor, an atmospheric temperature sensor (or atmospheric temperature signal), a vehicle speed sensor (or vehicle speed signal), a water pump, a thermal management module (which may include an electronic thermostat), and a radiator fan.

[0026] The engine outlet temperature sensor is used to detect the temperature of the coolant at the engine outlet. It is also called a water temperature sensor and detects the actual water temperature of the engine.

[0027] An atmospheric temperature sensor or atmospheric temperature signal is used; the engine cooling system is hardwired to the atmospheric temperature sensor or receives the atmospheric temperature signal via a network such as CAN.

[0028] The vehicle speed sensor or vehicle speed signal is either hard-wired to the engine cooling system or received via a network such as CAN.

[0029] Water pumps control the circulation of cooling water;

[0030] Thermal management module: When the thermal management module is turned on, it means that some of the coolant is returned to the engine inlet after being cooled by the radiator.

[0031] A radiator fan is used to cool the cooling water flowing through the radiator.

[0032] This invention employs three control modes for fan control under different operating conditions.

[0033] See Figure 1 The electronic fan control method of the present invention includes the following steps:

[0034] First control mode: Intelligent fan control mode under fuel cut-off conditions

[0035] See Figure 2 Fuel Cut-off Condition Fan Intelligent Control Mode: When the engine is in a fuel cut-off condition that meets the judgment conditions, the fan operation time is not less than the fan operation time set in the fuel cut-off condition fan intelligent control mode. The judgment conditions are recorded, and the battery SOC at the time of satisfaction is entered, i.e., SOC Start The process involves various changes in battery SOC during the time before the fan starts, and each fuel cut-off condition triggers only one of these conditions. The specific process is as follows:

[0036] Fuel cut-off condition judgment criteria: The following conditions must be met simultaneously:

[0037] 1. Engine fuel cut-off request;

[0038] 2. The difference between the actual engine coolant temperature and the target coolant temperature exceeds the preset coolant temperature Q1 (Q1 is taken as 6℃ in this embodiment);

[0039] 3. The fan is on;

[0040] 4. Not in closed-loop control mode at engine speed;

[0041] 5. The vehicle's headlights are not on;

[0042] 6. The air conditioner is not turned on;

[0043] At this time, the engine is in fuel cut-off condition and does not need to perform closed-loop speed control. The engine power demand is reduced, the battery can be charged, and other electrical loads are not turned on (headlights are not turned on, air conditioning is not turned on). This ensures the consistency of operating conditions, and the fan start time can be precisely controlled.

[0044] Fan start time: The default fan start time T1 in the first control mode is set to a fixed value, which is 5 seconds in this embodiment. The maximum value of this default time and the time of other function requests to start the fan (control of other function requests to start the fan is not within the scope of this technology) is taken as the final fan start time, that is, the fan start time is not less than the fan start time set in the first control mode.

[0045] Battery SOC variation: There is an optimal safe range for battery life; if it is too low or too high, it will damage the battery's lifespan. In this embodiment, a battery SOC below 30% is considered too low; a battery SOC above 80% is considered too high; and a battery SOC between 30% and 80% is considered normal.

[0046] Record the battery's State of Charge (SOC) at the moment when all six fuel cut-off conditions are met. Start The change in battery SOC during the time T2 = T1 - ΔT before the fan starts (the fan start time is not less than T1 time, only the time T2 before the fan starts is considered, where ΔT is not greater than 0.5 times T1 and not less than 0.2 times T1, in this embodiment ΔT is taken as 0.3 times T1) during the process of satisfying the above 6 fuel cut-off conditions, that is, reading the maximum battery SOC value SOC. Max and the minimum SOC of the battery Min Battery SOC at time T2 before fan starts: SOC T2

[0047] 1. If SOC Start Too low, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the first preset value (±5% in this embodiment), then the default fan start time is immediately updated to T1' = T2 + (T1 - T2) * 0.8, but not less than 0.2 times T1.

[0048] 2. If SOC Start Too low, and SOC Start -SOC T2 If the value exceeds the second preset value (10% in this embodiment), it indicates that the SOC is decreasing. To avoid the decrease in SOC, the fan start time needs to be reduced to maintain a smooth change in SOC. Therefore, the default fan start time is immediately updated to T1' = T2 + (T1 - T2) * 0.5, but not less than 0.2 times T1.

[0049] 3. If SOC Start Too high, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the third preset value (±5% in this embodiment), then the default fan start time is immediately updated to T1' = T2 + (T1 - T2) * 1.2, but not more than twice T1.

[0050] 4. If SOC Start Too high, and SOC Start -SOC T2 If the value does not exceed the fourth preset value (which is a negative value, and in this embodiment it is -10%), it indicates that the SOC is increasing, which means that the battery power is too high and more electrical load can be consumed. In this case, the default fan start time is immediately updated to T1' = T2 + (T1 - T2) * 1.5, but not exceeding twice T1.

[0051] 5. If SOC is normal, and SOC Start -SOC T2 If the value exceeds the fifth preset value (10% in this embodiment), it indicates that the SOC is decreasing. To avoid the decrease in SOC, the fan start time needs to be reduced to maintain a smooth change in SOC. Therefore, the default fan start time is immediately updated to T1' = T2 + (T1 - T2) * 0.2, but not less than 0.2 times T1.

[0052] 6. If SOC Start Normal, and SOC Start -SOC T2 If the value does not exceed the sixth preset value (which is a negative value, and in this embodiment it is -10%), it indicates that the SOC is increasing, which means that the battery power is too high and more electrical load can be consumed. In this case, the default fan start time is immediately updated to T1' = T2 + (T1 - T2) * 1.25, but not exceeding twice T1.

[0053] 7. If SOC Start Normal, and SOC Start SOC MaxSOC Min SOC T2 If the difference between the four values ​​does not exceed the seventh preset value (±5% in this embodiment), then the default fan start time is T1' = T1.

[0054] The default time T1' and the time of other function requests for fan on (the control of other function requests for fan on is not within the scope of this technology) are taken as the maximum value as the final fan on duration.

[0055] The priority of the above 7 situations decreases from one to the next, and only one of them is triggered each time the fuel is cut off.

[0056] The first control mode does not consider the power requested by the fan; it only controls the duration of the fan's operation while it is running.

[0057] Second control mode: Power acceleration fan control limited mode

[0058] See Figure 3 The power acceleration fan control limited mode: When the engine's starting power output request approaches its limit, the fan's operating power is limited. Simultaneously, based on meeting all judgment conditions, the requested fan electrical power is controlled. The rate of change of the requested fan electrical power is jointly determined by the difference between the actual and target water temperatures and the ratio of the engine's requested firing torque to its maximum torque. Furthermore, the knock preset coefficient is optimized based on the occurrence of knock. The specific process is as follows:

[0059] When the engine's starting power output request is close to its limit, the fan's operating power is limited.

[0060] Starting conditions: The conditions for entering the power acceleration fan control restricted mode must be met simultaneously:

[0061] 1. The engine requests a firing torque close to the maximum torque that the engine can currently provide; (wherein the maximum engine torque can be found in patent CN202010632793.4 "Method for Determining the Maximum Output Torque of a Gasoline Engine". In this embodiment, if the engine requests a firing torque exceeding the maximum torque multiplied by a preset coefficient k (in this embodiment, the preset coefficient k is 98%) and the duration exceeds 0.8s, then the engine requests a firing torque close to the maximum torque that the engine can currently provide.)

[0062] 2. Low battery SOC; meaning the battery charge is too low, limiting its ability to power the fan. In this embodiment, a battery SOC of no more than 25% is considered low.

[0063] 3. The accelerator pedal opening is large enough; in this embodiment, the accelerator pedal opening is greater than 98%, which is considered to be large enough.

[0064] 4. Turn on the air conditioner;

[0065] 5. Vehicle speed is within a very low range. In this embodiment, a vehicle speed below 8 km / h is considered very low.

[0066] Next, control the fan to request electrical power, and simultaneously optimize the knock preset coefficient k based on the knock occurrence situation:

[0067] The process of controlling the fan to request electrical power is as follows:

[0068] First, control the fan to request 0 power, meaning the fan will not turn on.

[0069] Next, if the vehicle speed increases beyond the preset speed value and then stops decreasing (i.e., the speed increase refers to the moment when all five conditions are met simultaneously, and the speed is read from the start; if four conditions are still met simultaneously (the fifth speed condition is not considered and can be ignored), and the speed increases beyond the preset speed value (in this embodiment, the preset speed value is 2 km / h), then the fan's requested power change rate is gradually increased. This fan requested power change rate is determined by the difference between the actual and target water temperatures (referred to as the water temperature difference) and the ratio of the engine's requested torque to its maximum torque (referred to as the torque ratio). The larger the water temperature difference and the smaller the torque ratio, the greater the fan's requested power. The fan requested power change rate in this embodiment is calibrated as shown in Table 1 below.

[0070] Table 1

[0071]

[0072] Optimize the detonation preset coefficient: Optimize the detonation preset coefficient k based on the detonation occurrence conditions. The specific process is as follows:

[0073] If detonation occurs in this operating mode, and the difference between the maximum detonation delay angle requested (the maximum detonation delay angle requested is the maximum allowable detonation angle after detonation occurs, which is a calibration value, and is 10° in this embodiment) and the actual detonation delay angle is within a preset range (2° to 5° in this embodiment), then the detonation preset coefficient k in this control mode is 1.2 times the original value to avoid further detonation and ensure that the fan starts as early as possible; at this time, the updated detonation preset coefficient k is not stored after the change.

[0074] If detonation occurs in this operating mode, and the difference between the maximum detonation delay angle requested (the maximum detonation delay angle requested is the maximum allowable detonation angle after detonation, which is a calibration value; in this embodiment, it is 10°) and the actual detonation delay angle does not exceed the detonation preset value (in this embodiment, it is 2°), then the detonation preset coefficient k in this control mode is 1.5 times the original value to avoid further occurrence of severe detonation and ensure that the fan starts as early as possible. At this time, the updated preset coefficient k is changed and stored without powering down. Then, the updated preset coefficient k is used to determine whether to enter this control mode in the next operation.

[0075] The third control mode: Normal operating mode

[0076] See Figure 4 Normal operating mode: The fan's requested power is determined based on the actual water temperature and the target water temperature difference. If the rate of water temperature change exceeds a preset value within a preset time after the high-speed fan switches to low-speed fan operation, or after the high-speed fan switches to low-speed fan operation, the preset coefficient is adjusted and stored after power-down. The updated preset coefficient is used to determine whether the fan should operate at high / low speed, and the fan operation scheme is set according to the relationship between the updated preset coefficient and the updated preset value. The specific process is as follows:

[0077] All other work modes besides the two mentioned above fall under this work mode.

[0078] Fan power demand determination criteria: In this operating mode, the fan power demand is determined based on the actual water temperature and the target water temperature difference (water temperature difference) and the actual water temperature, as shown in Table 2 below:

[0079] Table 2

[0080]

[0081] Preset coefficient adjustment: If, after the high-speed fan switches to the low-speed fan, the rate of change of water temperature exceeds the first preset value r1 (0.5℃ / 10ms) within the first preset time T3 (2s in this embodiment) and the total duration exceeds the first preset time threshold T31 (1.5s in this embodiment), then the actual water temperature and the fan power demand under the water temperature difference at the time of fan state switching are increased, and the first preset coefficient is increased to R11 (that is, the fan power demand in the table above is multiplied by the first preset coefficient R11, where R11 is 1 in this embodiment). 125); Similarly, if the rate of change of water temperature exceeds the second preset value r2 (-0.5℃ / 10ms) within the first preset time T3 (2s in this embodiment) after the process of switching from high-speed fan to low-speed fan, and the total duration of the maintenance exceeds the second preset time threshold T32 (1.5s in this embodiment), then the actual water temperature and the fan power under the water temperature difference at the time of fan state switching are reduced, and the second preset coefficient is reduced to R21 (that is, the fan requested power in the table above is multiplied by the preset coefficient R21, and R11 is 0.988 in this embodiment).

[0082] If, during the transition from low-speed fan to high-speed fan, the rate of change in water temperature exceeds the third preset value r3 (0.5℃ / 10ms) within the second preset time T4 (3s in this embodiment) and the total duration of this value exceeds the third preset time threshold T41 (2.2s in this embodiment), then the actual water temperature and the requested power of the fan under the temperature difference at the moment of fan state switching are increased, and the third preset coefficient is increased to R12 (i.e., the requested power of the fan in the table above is multiplied by the preset coefficient R12, where R12 is greater than R11, and R12 is 1.2 in this embodiment); In cases where the rate of change of water temperature exceeds the fourth preset value r4 (-0.5℃ / 10ms) within the second preset time T4 (3s in this embodiment) after the high-speed fan switches to the low-speed fan, and the total duration of the maintenance exceeds the fourth preset time threshold T42 (2.2s in this embodiment), then the actual water temperature and the fan power under the water temperature difference at the time of fan state switching are reduced, and the fourth preset coefficient is reduced to R22 (that is, the fan power requested in the table above is multiplied by the preset coefficient R22, where R22 is not greater than R21, and R11 is 0.98 in this embodiment).

[0083] Preset coefficient update: The first preset coefficient R11, the second preset coefficient R21, the third preset coefficient R12 and the fourth preset coefficient R22 are all stored after power-down. The stored and updated coefficients are used to determine whether the fan is turned on at high speed / low speed.

[0084] If the fan request power multiplied by the updated preset coefficient in Table 2 is greater than the preset value A (20W in this embodiment), then the high-speed fan is turned on; if the fan request power multiplied by the updated preset coefficient in Table 2 is not greater than the preset value A, but greater than the preset value B (10W in this embodiment), then the low-speed fan is turned on; if the fan request power multiplied by the updated preset coefficient is less than the preset value B, then the fan is turned off.

[0085] See Figure 5 The electronic fan control device of the present invention employs three control modes for various operating conditions, including the following components:

[0086] Fuel Cut-off Condition Fan Intelligent Control Mode Module: When the engine is in a fuel cut-off condition that meets the judgment conditions, the fan operation time is not less than the fan operation time set by the fuel cut-off condition fan intelligent control mode. The judgment conditions are recorded, and the battery SOC at the time of satisfaction is entered. Start The battery SOC changes during the time before the fan turns on, and only one of the conditions is triggered in each fuel cut-off condition.

[0087] Power Acceleration Fan Control Limited Mode Module: When the engine's starting power output request approaches its limit, the fan's operating power is limited. At the same time, based on meeting all judgment conditions, the requested electric power of the fan is controlled. The rate of change of the requested electric power of the fan is determined by the difference between the actual water temperature and the target water temperature, the ratio of the engine's requested arc torque to the maximum torque, and the knock preset coefficient is optimized according to the knock occurrence situation.

[0088] Normal operating mode module: Determines the requested power of the fan based on the actual water temperature and the target water temperature difference. If the rate of change of the water temperature exceeds the preset value within a preset time after the high-speed fan turns on to the low-speed fan, the preset coefficient is adjusted and stored after power-down. The updated preset coefficient is used to determine whether the fan should be turned on at high speed or low speed, and the fan start scheme is set according to the relationship between the updated preset coefficient and the updated preset value.

[0089] The key technical points and technical principles of this invention are as follows:

[0090] 1. Setting fan control for different modes;

[0091] 2. Fan control methods in different modes.

[0092] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0093] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A control method for an electronic fan, characterized in that: Three control modes are used for fan control under various operating conditions, including the following steps: Fuel Cut-off Condition Fan Intelligent Control Mode: When the engine is in a fuel cut-off condition that meets the judgment conditions, the fan operation time is not less than the fan operation time set by the fuel cut-off condition fan intelligent control mode. The judgment conditions are recorded, and the battery SOC at the time of satisfaction is entered. Start The battery SOC changes during the time before the fan turns on, and only one of the conditions is triggered in each fuel cut-off condition. Power acceleration fan control limited mode: When the engine start-up power output request is close to the limit, the fan power is limited. At the same time, based on meeting all judgment conditions, the requested electric power of the fan is controlled. The rate of change of the requested electric power of the fan is determined by the difference between the actual water temperature and the target water temperature, the ratio of the requested torque of the engine to the maximum torque, and the knock preset coefficient is optimized according to the knock occurrence situation. Normal operating mode: The fan power request is determined based on the actual water temperature and the target water temperature difference. If the water temperature change rate exceeds the preset value within a preset time after the high-speed fan switches to low-speed fan operation or after the high-speed fan switches to low-speed fan operation, the preset coefficient is adjusted and the power is turned off to store the data. The updated preset coefficient is used to determine whether the fan is turned on at high speed or low speed, and the fan operation scheme is set according to the relationship between the updated preset coefficient and the updated preset value.

2. The control method for an electronic fan according to claim 1, characterized in that: The specific steps of the intelligent fan control mode under the oil cut-off condition are as follows: Fuel cut-off condition judgment conditions include: engine fuel cut-off request conditions, difference between actual engine coolant temperature and target coolant temperature conditions, fan status conditions, engine speed closed-loop control conditions, vehicle headlight status conditions, and air conditioning status conditions. Fan start time: Set the default fan start time T1 in the intelligent fan control mode under oil cut-off condition to a fixed value. The maximum value of the default fan start time T1 and the fan start time requested by other functions shall be taken as the final fan start time. Battery SOC changes: Record the battery SOC at the moment when all six fuel cut-off conditions are simultaneously met. Start The change in battery SOC within the time T2 before the fan starts during the process of satisfying the above 6 fuel cut-off conditions, i.e., reading the maximum battery SOC value. Max and the minimum SOC of the battery Min And the battery SOC at time T2 before the fan turns on: SOC T2 .

3. The control method for an electronic fan according to claim 2, characterized in that: The specific conditions for the sub-step of determining the fuel cutoff condition are as follows: Engine fuel cut-off request: Engine fuel cut-off request; Difference between actual engine coolant temperature and target coolant temperature: The difference between the actual engine coolant temperature and the target coolant temperature exceeds the preset coolant temperature Q1; Fan status: The fan is on; Engine speed closed-loop control condition: Not in engine speed closed-loop control condition; Vehicle headlight status: Vehicle headlights are off; Air conditioning status: Air conditioning is not turned on.

4. The control method for an electronic fan according to claim 3, characterized in that: The specific process of the sub-step regarding battery SOC change is as follows: First default start time: If SOC Start Too low, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the first preset value, then the default fan start time will be updated to T1' = T2 + (T1 - T2) * 0.8, but not less than 0.2 times T1. Second default start time: If SOC Start Too low, and SOC Start -SOC T2 If the value exceeds the second preset value, the default fan start time will be updated to T1' = T2 + (T1 - T2) * 0.5, but not less than 0.2 times T1. Third, default start time: If SOC Start Too high, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the third preset value, then the default fan start time will be updated to T1' = T2 + (T1 - T2) * 1.2, but not exceeding twice T1. Fourth, enable the default time: if SOC Start Too high, and SOC Start -SOC T2 If the value does not exceed the fourth preset value, then update the default fan start time to T1' = T2 + (T1 - T2) * 1.5, but not exceeding twice T1; Fifth, enable the default time: if the SOC is normal, and the SOC... Start -SOC T2 If the value exceeds the fifth preset value, the default fan start time will be updated to T1' = T2 + (T1 - T2) * 0.2, but not less than 0.2 times T1. Sixth, enable default time: if SOC Start Normal, and SOC Start -SOC T2 If the value does not exceed the sixth preset value, then update the default fan start time to T1' = T2 + (T1 - T2) * 1.25, but not exceeding twice T1; Seventh, enable default time: if SOC Start Normal, and SOC Start SOC Max SOC Min SOC T2 If the difference between the four values ​​does not exceed the seventh preset value, then the default fan start time for this operation is T1' = T1. Final fan start duration: The maximum value of the above default times T1' and the fan start time requested by other functions is taken as the final fan start duration. Each oil cut-off condition will only trigger one of the conditions between the first default start time and the seventh default start time.

5. The control method for an electronic fan according to claim 4, characterized in that: The specific process of the power acceleration fan control limited mode steps is as follows: Starting conditions: Engine request torque condition: The engine requests a torque close to the maximum torque that the engine can currently provide; Battery SOC condition: Battery SOC is low; Accelerator pedal opening condition: The accelerator pedal opening is large enough; Air conditioner status: Air conditioner is on; Speed ​​range condition: The vehicle speed is within a very low range; Controlling the fan's requested power: First, control the fan's requested power to be 0, that is, the fan is not turned on; then, if the vehicle speed increases beyond the preset speed value and then no longer decreases, the rate of change of the fan's requested power is gradually increased. The rate of change of the fan's requested power is determined by the difference between the actual water temperature and the target water temperature, and the ratio of the engine's requested torque to the maximum torque. The greater the water temperature difference and the smaller the torque ratio, the greater the fan's requested power. Optimize the knock preset coefficient: If the difference between the maximum ignition angle requested for knock delay and the actual knock delay ignition angle is within the preset range after knock occurs, or if knock occurs in this working mode and the difference between the maximum ignition angle requested for knock delay and the actual knock delay ignition angle does not exceed the knock preset value, adjust the knock preset coefficient k for various situations.

6. The control method for an electronic fan according to claim 5, characterized in that: The specific process of the sub-step for optimizing the pre-set detonation coefficient is as follows: First knock preset coefficient k adjustment: If knock occurs in this working mode, and the difference between the maximum ignition angle requested for knock and the actual knock ignition angle is within the preset range, then the knock preset coefficient k in the power acceleration fan control limited mode is 1.2 times the original value. At this time, the updated knock preset coefficient k is not stored after the change. Second knock preset coefficient k adjustment: If knock occurs in this working mode, and the difference between the knock request to delay the maximum ignition angle and the actual knock delay ignition angle does not exceed the knock preset value, then the knock preset coefficient k in the power acceleration fan control limited mode is 1.5 times the original value. At this time, the updated knock preset coefficient k is changed and stored after power-down. Then, the updated knock preset coefficient k is used to determine whether to enter the power acceleration fan control limited mode in the next operation.

7. The control method for an electronic fan according to claim 6, characterized in that: The specific process of the normal working mode steps is as follows: Conditions for determining the requested power of the fan: The requested power of the fan is determined based on the actual water temperature and the difference between the target water temperature and the actual water temperature. Preset coefficient adjustment: If the water temperature change rate exceeds the preset value within a preset time after the high-speed fan switches to the low-speed fan, the preset coefficient will be adjusted in four different cases to change the actual water temperature at the time of fan state switching and the fan's requested power under the water temperature difference. Preset coefficient update: Various preset coefficients are stored after power-down. The updated preset coefficients are used to determine whether the fan should be turned on at high speed or low speed. The fan is turned on at high speed, low speed, or off according to the relationship between the updated preset coefficients and the updated preset values ​​A and B.

8. The control method for an electronic fan according to claim 7, characterized in that: The specific process of the preset coefficient adjustment sub-step is as follows: First type of preset coefficient setting: If the rate of change of water temperature within the first preset time T3 exceeds the first preset value r1 and the total duration exceeds the first preset time threshold T31 after the high-speed fan is switched to the low-speed fan, then the actual water temperature at the time of fan state switching and the fan power requested under the water temperature difference are increased, and the first preset coefficient R11 is increased. Similarly, if the rate of change of water temperature within the first preset time T3 exceeds the second preset value r2 and the total duration exceeds the second preset time threshold T32 after the high-speed fan switches to the low-speed fan, then the actual water temperature and the fan power under the water temperature difference during the fan state switch are reduced, and the second preset coefficient R21 is reduced. The second type of preset coefficient setting: If the rate of change of water temperature within the second preset time T4 after the low-speed fan turns on to the high-speed fan turns on exceeds the third preset value r3 and the total duration exceeds the third preset time threshold T41, then the actual water temperature and the fan power requested by the fan under the water temperature difference at the time of fan state switching are increased, and the third preset coefficient R12 is increased; similarly, if the rate of change of water temperature within the second preset time T4 after the high-speed fan turns on to the low-speed fan turns on exceeds the fourth preset value r4 and the total duration exceeds the fourth preset time threshold T42, then the actual water temperature and the fan power under the water temperature difference at the time of fan state switching are decreased, and the fourth preset coefficient R22 is decreased.

9. The control method for an electronic fan according to claim 8, characterized in that: The specific process of the preset coefficient update sub-step is as follows: The first preset coefficient R11, the second preset coefficient R21, the third preset coefficient R12 and the fourth preset coefficient R22 are all stored after power-down. The updated preset coefficients are then used to determine whether the fan is turned on at high speed or low speed. If the fan's requested power multiplied by the updated preset coefficient is greater than the preset value A, then the high-speed fan will be activated. If the fan's requested power multiplied by the updated preset coefficient is not greater than the preset value A, but greater than the preset value B, then the low-speed fan is turned on; if the fan's requested power multiplied by the updated preset coefficient is less than the preset value B, then the fan is turned off.

10. A control device for an electronic fan, comprising a computer program, characterized in that: The computer program is capable of executing the control method for the electronic fan as described in any one of claims 1 to 9.

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