A method for controlling an electric fan of a vehicle

Abstract

The present invention relates to a method for controlling an electric fan of an automobile, comprising obtaining an engine water outlet temperature, an engine air intake temperature, an air conditioning refrigerant pressure, a vehicle speed and a retarder gear switch state; formulating different fan calling conditions according to the engine water outlet temperature, the engine air intake temperature, the air conditioning refrigerant pressure, the vehicle speed and the retarder gear switch state, executing an "or" logic between different fan calling conditions, calling the fan when any one of the fan calling conditions is met, and calling different fan speed duty ratios according to corresponding control strategies, and when multiple fan calling conditions are met at the same time, the fan speed duty ratio is executed according to the highest one; the present invention can ensure that the cooling circulation water temperature is close to a balanced stable state, reduce the fan meshing frequency, and thus achieve the purpose of reducing the fuel consumption of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile fan control, and in particular to a method for controlling an automobile electric fan. Background Art

[0002] At present, the commonly used fan control strategies are: the fan speed duty cycle increases linearly according to the gradual increase of the engine water temperature setting value; the fan speed duty cycle increases linearly according to the gradual increase of the engine intake temperature setting value; however, the water temperature changes at different rates: when the water temperature changes slowly, the fan speed duty cycle can increase linearly; when the water temperature changes quickly, the fan speed needs to be increased quickly, and the fan speed duty cycle cannot increase linearly, otherwise it will cause the engine coolant high temperature alarm;

[0003] When the air conditioning refrigerant pressure is higher than the medium pressure value, the electronically controlled fan directly connects and runs at the highest speed; however, when the refrigerant pressure reaches the medium pressure and the fan is directly connected, if the air conditioning refrigerant pressure drops below the medium pressure threshold, the electronically controlled fan directly connects and the state is called. The fan directly connects and causes the fan engagement frequency to increase (i.e., the fan directly connects for a long time and the fan power consumption is high), which increases the fuel consumption of the vehicle.

[0004] When the retarder switch is turned on or the retarder is called by combined braking, the electronically controlled fans are directly connected and run at the highest speed. However, when the retarder switch is turned on or the retarder is called by combined braking, there is no need for direct fan connection when the water temperature is low. Direct fan connection will increase the fan engagement frequency and increase the fuel consumption of the whole vehicle;

[0005] In order to solve various deficiencies of commonly used fan control strategies, the present invention relates to an electronically controlled fan control strategy, which adds a water temperature change rate factor condition, a fan delay exit method after the air conditioning refrigerant pressure drops from medium pressure to less than the medium pressure threshold, and adds water temperature and time threshold factor conditions after the retarder switch is turned on or when the retarder is called by combined braking. Through these factor condition changes, the cooling cycle water temperature is ensured to be close to a balanced stable state, and the fan meshing frequency is reduced, thereby achieving the purpose of reducing vehicle fuel consumption. Summary of the invention

[0006] The object of the present invention is to provide a method for controlling an electric fan of an automobile in view of the deficiencies in the prior art.

[0007] The present invention is achieved by adopting the following technical solutions:

[0008] A method for controlling an electric fan of an automobile, the method comprising:

[0009] Obtain engine water outlet temperature, engine air intake temperature, air conditioning refrigerant pressure, vehicle speed and retarder gear switch status;

[0010] Different fan calling conditions are formulated according to the engine water outlet temperature, engine intake temperature, air conditioning refrigerant pressure, vehicle speed and retarder gear switch status. The "or" logic is executed between different fan calling conditions. When any fan calling condition is met, the fan is called, and different fan speed duty cycles are called according to the corresponding control strategy. When multiple fan calling conditions are met at the same time, the fan speed duty cycle is executed according to the highest one.

[0011] As a further explanation of the invention, the engine outlet water temperature is collected in real time, and the fan speed duty cycle changes nonlinearly with the engine outlet water temperature and the engine speed.

[0012] As a further illustration of the invention, when the engine outlet water temperature is less than the set temperature T1, the fan is not called;

[0013] When the engine outlet water temperature ≥ set temperature T1 and the temperature rises, it is divided into:

[0014] When the time for each unit ℃ increase in the engine outlet water temperature is greater than the set time threshold upper limit, the fan speed duty cycle is executed according to the corresponding value of the engine outlet water temperature-engine speed table;

[0015] When the lower limit of the set time threshold is less than the time per unit ℃ increase in the engine outlet water temperature ≤ the upper limit of the set time threshold, the fan speed duty cycle is executed according to the set multiple a of the corresponding value of the engine outlet water temperature-engine speed table; among which, when the fan speed duty cycle is ≥100%, it is executed at 100%;

[0016] When the time for each unit ℃ increase in the engine outlet water temperature is ≤ the lower limit of the set time threshold, the fan speed duty cycle is executed according to the engine outlet water temperature-engine speed table set multiple b; among which, when the fan speed duty cycle is ≥100%, it is executed at 100%;

[0017] When the engine outlet water temperature is ≥ the set temperature T1 and the temperature decreases: the fan speed duty cycle continues to run for the set time t1 according to the fan speed duty cycle before the temperature decreases, and then executes according to the corresponding value of the engine outlet water temperature-engine speed table.

[0018] As a further explanation of the invention, the engine intake temperature is collected in real time, and the fan speed duty cycle varies nonlinearly with the engine intake temperature and the engine speed.

[0019] As a further illustration of the invention, when the engine intake temperature is less than the set temperature T2, the fan is not called;

[0020] When the engine intake temperature is ≥ the set temperature T2, the fan speed duty cycle is executed according to the corresponding value of the engine intake temperature-engine tachometer.

[0021] As a further explanation of the invention, when the vehicle speed is less than the set vehicle speed threshold, it is divided into:

[0022] When the air conditioner is turned on, the fan speed duty cycle is executed according to the set value d;

[0023] When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value e;

[0024] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to f for set time t2 and then set to d;

[0025] When the lower limit of the set speed threshold is ≤ vehicle speed ≤ the upper limit of the set speed threshold, it is divided into:

[0026] When the air conditioner is turned on, the fan speed duty cycle is executed according to the set value g;

[0027] When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value h;

[0028] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to i for set time t3 and then to g;

[0029] When the vehicle speed is greater than the set upper speed threshold, it is divided into:

[0030] When the air conditioner is turned on, the fan is not called;

[0031] When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value j;

[0032] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to the set value k and the fan is not called after the set time t4;

[0033] When the air conditioning refrigerant pressure rises from medium pressure to high pressure, the fan speed duty cycle is executed according to the set value m;

[0034] When the air conditioning refrigerant pressure drops from high pressure to medium pressure, the fan speed duty cycle is executed according to the set value n for the set time t5 and then according to the set value j.

[0035] As a further explanation of the invention, when the retarder gear switch is turned on, it is divided into:

[0036] When the retarder outlet water temperature is less than the set temperature T3, the fan will not be called;

[0037] When the retarder outlet water temperature is ≥ the set temperature T3, the fan speed duty cycle is executed at 100%.

[0038] As a further explanation of the invention, when the retarder gear switch is closed, it is divided into:

[0039] When the duration of the combined braking retarder is less than the set time t6, the fan will not be called;

[0040] When the duration of the combined braking retarder call is ≥ the set time t6, the fan speed duty cycle is called to 100%.

[0041] Compared with the prior art, the present invention has the following beneficial technical effects:

[0042] The present invention formulates different fan control strategies based on the engine water outlet temperature, the engine air intake temperature, the air conditioning refrigerant pressure, the vehicle speed and the retarder gear switch state, wherein the fan speed duty cycle performs nonlinear changes based on the engine water outlet temperature change rate, and similarly, the fan speed duty cycle performs nonlinear changes based on the engine air intake temperature change rate, and the fan speed duty cycle performs different set values ​​according to the corresponding relationship between the vehicle speed and the air conditioning refrigerant pressure, and the fan speed duty cycle performs different set values ​​when the water temperature and the continuous use time are increased after the retarder switch is turned on or when the retarder is called in combination with braking; through different control strategies, the cooling circulation water temperature is ensured to be close to a balanced stable state, the fan engagement frequency is reduced, and the purpose of reducing fuel consumption is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0044] like Figure 1 As shown, a method for controlling an electric fan of a vehicle, the method comprising:

[0045] Obtain engine water outlet temperature, engine air intake temperature, air conditioning refrigerant pressure, vehicle speed and retarder gear switch status;

[0046] Different fan calling conditions are formulated according to the engine water outlet temperature, engine intake temperature, air conditioning refrigerant pressure, vehicle speed and retarder gear switch status. The "or" logic is executed between different fan calling conditions. When any fan calling condition is met, the fan is called, and different fan speed duty cycles are called according to the corresponding control strategy. When multiple fan calling conditions are met at the same time, the fan speed duty cycle is executed according to the highest one.

[0047] Control strategy 1

[0048] The engine outlet water temperature is collected in real time. As the engine outlet water temperature and engine speed vary, the fan speed duty cycle changes nonlinearly.

[0049] When the engine outlet water temperature is less than the set temperature T1, the fan will not be called;

[0050] When the engine outlet water temperature ≥ set temperature T1 and the temperature rises, it is divided into:

[0051] When the time for each unit ℃ increase in the engine outlet water temperature is greater than the set time threshold upper limit, the fan speed duty cycle is executed according to the corresponding value of the engine outlet water temperature-engine speed table;

[0052] When the lower limit of the set time threshold is less than the time per unit ℃ increase in the engine outlet water temperature ≤ the upper limit of the set time threshold, the fan speed duty cycle is executed according to the set multiple a of the corresponding value of the engine outlet water temperature-engine speed table; among which, when the fan speed duty cycle is ≥100%, it is executed at 100%;

[0053] When the time for each unit ℃ increase in the engine outlet water temperature is less than the lower limit of the set time threshold, the fan speed duty cycle is executed according to the engine outlet water temperature-engine speed table set multiple b; among which, when the fan speed duty cycle is ≥100%, it is executed at 100%;

[0054] When the engine outlet water temperature is ≥ the set temperature T1 and the temperature decreases: the fan speed duty cycle continues to run for the set time t1 according to the fan speed duty cycle before the temperature decreases, and then executes according to the corresponding value of the engine outlet water temperature-engine speed table.

[0055] In the above, the set temperature T1 is preferably 92°C, and the engine water outlet temperature-engine speed table is formulated as shown in the table below:

[0056] Table 1 Engine outlet water temperature-engine speed

[0057]

[0058] When the engine outlet water temperature is less than 92°C, the fan will not be used;

[0059] When the engine outlet water temperature is ≥92℃ and the temperature rises, it is divided into:

[0060] When the time for the engine outlet water temperature to increase by 2°C is greater than the upper limit of 45s, the fan speed duty cycle is based on the corresponding value of the engine outlet water temperature - engine speed table;

[0061] When 15s < the time for each 2°C increase in the engine outlet water temperature and ≤ 45s, the fan speed duty cycle shall be 1.2 times the corresponding value of the engine outlet water temperature - engine speed table; among which, when the fan speed duty cycle is ≥ 100%, it shall be 100%;

[0062] When the time for the engine outlet water temperature to increase by 2°C is ≤15s, the fan speed duty cycle shall be 1.4 times the engine outlet water temperature minus the engine speed table; when the fan speed duty cycle is ≥100%, it shall be 100%;

[0063] When the engine outlet water temperature is ≥92℃ and the temperature drops: the fan speed duty cycle continues to run for 15s according to the fan speed duty cycle before the temperature drops, and then runs according to the corresponding value of the engine outlet water temperature-engine tachometer.

[0064] Control strategy 2

[0065] The engine intake temperature is collected in real time. As the engine intake temperature and engine speed vary, the fan speed duty cycle changes nonlinearly.

[0066] When the engine intake temperature is less than the set temperature T2, the fan is not called;

[0067] When the engine intake temperature is ≥ the set temperature T2, the fan speed duty cycle is executed according to the corresponding value of the engine intake temperature-engine tachometer.

[0068] The above set temperature T2 is preferably 65°C, and the engine intake temperature-engine speed table is formulated as shown in the table below:

[0069] Table 2 Engine Intake Temperature-Engine Speed

[0070]

[0071] When the engine intake temperature is less than 65°C, the fan will not be used;

[0072] When the engine intake temperature is ≥65℃, the fan speed duty cycle is executed according to the corresponding value of the engine intake temperature-engine tachometer.

[0073] Control strategy three

[0074] When the vehicle speed is less than the set speed threshold, it is divided into:

[0075] When the air conditioner is turned on, the fan speed duty cycle is executed according to the set value d;

[0076] When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value e;

[0077] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to f for set time t2 and then set to d;

[0078] When the lower limit of the set speed threshold is ≤ vehicle speed ≤ the upper limit of the set speed threshold, it is divided into:

[0079] When the air conditioner is turned on, the fan speed duty cycle is executed according to the set value g;

[0080] When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value h;

[0081] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to i for set time t3 and then to g;

[0082] When the vehicle speed is greater than the set upper speed threshold, it is divided into:

[0083] When the air conditioner is turned on, the fan is not called;

[0084] When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value j;

[0085] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to the set value k and the fan is not called after the set time t4;

[0086] When the air conditioning refrigerant pressure rises from medium pressure to high pressure, the fan speed duty cycle is executed according to the set value m;

[0087] When the air conditioning refrigerant pressure drops from high pressure to medium pressure, the fan speed duty cycle is executed according to the set value n for the set time t5 and then according to the set value j.

[0088] Above, when the vehicle speed is less than 5km / h, it is divided into:

[0089] When the air conditioner is turned on, the fan speed duty cycle is 50%;

[0090] When the air conditioner refrigerant pressure is ≥ medium pressure, the fan speed duty cycle is 100%;

[0091] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is 100% for 20 seconds and then 50%;

[0092] When 5km / h≤vehicle speed≤25km / h, it is divided into:

[0093] When the air conditioner is turned on, the fan speed duty cycle is 40%;

[0094] When the air conditioner refrigerant pressure is ≥ medium pressure, the fan speed duty cycle is 100%;

[0095] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is 100% for 20 seconds and then 40%;

[0096] When the vehicle speed is greater than 25km / h, it is divided into:

[0097] When the air conditioner is turned on, the fan is not called;

[0098] When the air conditioner refrigerant pressure is ≥ medium pressure, the fan speed duty cycle is 80%;

[0099] When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to 80% for 20 seconds, and then the fan is not called;

[0100] When the air conditioning refrigerant pressure rises from medium pressure to high pressure, the fan speed duty cycle is 100%;

[0101] When the air conditioner refrigerant pressure drops from high pressure to medium pressure, the fan speed duty cycle is 100% for 20 seconds and then 80%.

[0102] The above description about the refrigerant pressure of air conditioners: high pressure: refrigerant pressure ≥3MPa; medium pressure: 1.5MPa<refrigerant pressure<3MPa; normal pressure: refrigerant pressure ≤1.5MPa; adjust according to actual conditions.

[0103] Control strategy 4

[0104] When the retarder gear switch is turned on, it is divided into:

[0105] When the retarder outlet water temperature is less than the set temperature T3, the fan will not be called;

[0106] When the retarder outlet water temperature is ≥ the set temperature T3, the fan speed duty cycle is executed at 100%.

[0107] Above, the set temperature T3 is preferably 88°C;

[0108] When the retarder gear switch is turned on, it is divided into:

[0109] When the retarder outlet water temperature is less than 88°C, the fan will not be called;

[0110] When the retarder outlet water temperature is ≥88℃, the fan speed duty cycle is 100%

[0111] When the retarder gear switch is closed, it is divided into:

[0112] When the duration of the combined braking retarder is less than the set time t6, the fan will not be called;

[0113] When the duration of the combined braking retarder call is ≥ the set time t6, the fan speed duty cycle is called to 100%.

[0114] Above, the setting time t6 is preferably 10s:

[0115] When the retarder gear switch is closed, it is divided into:

[0116] When the combined braking calls the retarder for a duration of less than 10s, the fan will not be called;

[0117] When the combined braking calls the retarder for a duration of ≥10s, the fan speed duty cycle is called to 100%.

[0118] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0119] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling an electric fan of an automobile, characterized in that: The method comprises: Obtain engine water outlet temperature, engine air intake temperature, air conditioning refrigerant pressure, vehicle speed and retarder gear switch status; Different fan calling conditions are formulated according to the engine water outlet temperature, engine intake temperature, air conditioning refrigerant pressure, vehicle speed and retarder gear switch status. The "or" logic is executed between different fan calling conditions. When any fan calling condition is met, the fan is called, and different fan speed duty ratios are called according to the corresponding control strategy. When multiple fan calling conditions are met at the same time, the fan speed duty ratio with the highest one is used. The engine outlet water temperature is collected in real time. As the engine outlet water temperature and engine speed vary, the fan speed duty cycle changes nonlinearly. When the engine outlet water temperature is less than the set temperature T1, the fan will not be called; When the engine outlet water temperature ≥ set temperature T1 and the temperature rises, it is divided into: When the time for each unit ℃ increase in the engine outlet water temperature is greater than the set time threshold upper limit, the fan speed duty cycle is executed according to the corresponding value of the engine outlet water temperature-engine speed table; When the lower limit of the set time threshold is less than the time per unit ℃ increase in the engine outlet water temperature ≤ the upper limit of the set time threshold, the fan speed duty cycle is executed according to the set multiple a of the corresponding value of the engine outlet water temperature-engine speed table; among which, when the fan speed duty cycle is ≥100%, it is executed at 100%; When the time for each unit ℃ increase in the engine outlet water temperature is ≤ the lower limit of the set time threshold, the fan speed duty cycle is executed according to the engine outlet water temperature-engine speed table set multiple b; among which, when the fan speed duty cycle is ≥100%, it is executed at 100%; When the engine outlet water temperature is ≥ the set temperature T1 and the temperature decreases: the fan speed duty cycle continues to run for the set time t1 according to the fan speed duty cycle before the temperature decreases, and then executes according to the corresponding value of the engine outlet water temperature-engine speed table.

2. The method for controlling an electric fan of a vehicle as claimed in claim 1, characterized in that: The engine intake temperature is collected in real time. As the engine intake temperature and engine speed vary, the fan speed duty cycle changes nonlinearly.

3. The method for controlling an electric fan of a vehicle as claimed in claim 2, characterized in that: When the engine intake temperature is less than the set temperature T2, the fan is not called; When the engine intake temperature is ≥ the set temperature T2, the fan speed duty cycle is executed according to the corresponding value of the engine intake temperature-engine tachometer.

4. The method for controlling an electric fan of a vehicle as claimed in claim 1, characterized in that: When the vehicle speed is less than the set speed threshold, it is divided into: When the air conditioner is turned on, the fan speed duty cycle is executed according to the set value d; When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value e; When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to f for set time t2 and then set to d; When the lower limit of the set speed threshold is ≤ vehicle speed ≤ the upper limit of the set speed threshold, it is divided into: When the air conditioner is turned on, the fan speed duty cycle is executed according to the set value g; When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value h; When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to i for set time t3 and then to g; When the vehicle speed is greater than the set upper speed threshold, it is divided into: When the air conditioner is turned on, the fan is not called; When the air conditioning refrigerant pressure ≥ medium pressure, the fan speed duty cycle is executed according to the set value j; When the air conditioner refrigerant pressure drops from medium pressure to normal pressure, the fan speed duty cycle is set to the set value k and the fan is not called after the set time t4; When the air conditioning refrigerant pressure rises from medium pressure to high pressure, the fan speed duty cycle is executed according to the set value m; When the air conditioning refrigerant pressure drops from high pressure to medium pressure, the fan speed duty cycle is executed according to the set value n for the set time t5 and then according to the set value j.

5. The method for controlling an electric fan of a vehicle as claimed in claim 1, characterized in that: When the retarder gear switch is turned on, it is divided into: When the retarder outlet water temperature is less than the set temperature T3, the fan will not be called; When the retarder outlet water temperature is ≥ the set temperature T3, the fan speed duty cycle is executed at 100%.

6. The method for controlling an electric fan of a vehicle as claimed in claim 5, characterized in that: When the retarder gear switch is closed, it is divided into: When the duration of the combined braking retarder is less than the set time t6, the fan will not be called; When the duration of the combined braking retarder call is ≥ the set time t6, the fan speed duty cycle is called to 100%.

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