JP3029448B2 - Engine electric fan control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electric fan control device for an engine.

[Related Art] Generally, a vehicle equipped with a water-cooled engine is provided with a radiator for cooling engine cooling water and an electric fan for blowing air to the radiator. Then, in order to control the on / off of the electric fan or the amount of air blow according to the cooling water temperature or the like (hereinafter, such control is referred to as air blow control)
An electric fan control device is provided.

Such an electric fan control device basically performs air blowing control based on a cooling water temperature detected by a water temperature sensor, and specifically, determines whether the cooling water temperature is higher than a set value. An electric fan control device configured to turn on / off an electric fan, and when a plurality of electric fans are provided, when a cooling water temperature exceeds a first set value, one electric fan is turned on and a second set value is set. An electric fan control device that turns on both electric fans when it exceeds the limit, or an electric fan control device that changes the number of revolutions of the electric fan according to the cooling water temperature (Japanese Unexamined Patent Application Publication No.
No. 60-75715). The water temperature sensor is usually provided facing a cooling water discharge passage connected to a cooling water discharge port of the water jacket. Also,
In addition to the cooling water temperature, the rate of change of the cooling water temperature over time,
There is also known an electric fan control device that performs air blowing control in consideration of an engine load and the like.

[Problems to be Solved by the Invention] However, in an automobile equipped with an electric fan control device that performs air blowing control based on at least a detection value of a water temperature sensor, the engine is not cooled sufficiently after the engine is stopped. When the engine is restarted (hereinafter referred to as warm restart), immediately after the engine starts,
A transient phenomenon occurs in which the electric fan starts to rotate suddenly and stops in a short time (hereinafter, this phenomenon is referred to as a rotation phenomenon immediately after starting), which causes noise and gives the driver discomfort. is there.

In addition, in a situation where overheating of the engine is likely to occur (for example, when driving on congested roads in summer) (when there is a concern about overheating), the above-described conventional electric fan control device that performs the air blowing control based on the cooling water temperature includes:
There is a problem that the response to overheating tends to be delayed.

The present invention has been made to solve the above-described conventional problems, and can prevent the occurrence of a rotation phenomenon immediately after the start of the electric fan at the time of a warm restart, and, when there is a concern about overheating, It is an object of the present invention to provide an electric fan control device for an engine, which can prevent occurrence of a wobble.

[Means for Solving the Problems] The present inventors have considered that the rotation phenomenon immediately after the start of the electric fan at the time of the warm restart is caused by the following causes.

That is, when the engine is stopped, the water pump is also stopped, and the circulation of the cooling water in the cooling system is stopped. For a while after that, the engine is maintained at a high temperature by its heat capacity, so that the cooling water staying in the water jacket has a high temperature. However, since the cooling water outside the water jacket (mainly inside the radiator) is rapidly cooled, the average temperature of the cooling water in the entire cooling system rapidly decreases. Here, when the engine is restarted (warm restart), the water pump is driven, and the high-temperature cooling water remaining in the water jacket is discharged to the cooling water discharge passage, and is thus detected by the water temperature sensor. The cooling water temperature becomes very high, and the electric fan is turned on. However, since the cooling water staying in the water jacket passes around the water temperature sensor in a relatively short time, the cooling water temperature detected by the water temperature sensor soon returns to normal, and the average temperature of the entire cooling water The electric fan is turned off unless the temperature is extremely high. In this way, a rotation phenomenon occurs immediately after starting.

According to a first aspect of the present invention, there is provided an electric fan control device for an engine that controls an electric fan that blows to a radiator, based on the above-described considerations, in order to achieve the object described above. A cooling water temperature detecting means for detecting a cooling water temperature, and controlling the air blowing of the electric fan according to an output value of the cooling water temperature detecting means and at least a criterion set in advance based on at least the cooling water temperature; After the start, the cooling water is circulated in the cooling system by driving the water pump, and the temperature of the cooling water in the high-temperature portion is reduced, so that the approximate average temperature of the cooling water in the entire cooling system can be detected in this portion. An electric fan control device for an engine, wherein the air blowing control is stopped for a predetermined time until the control.

Also, the present inventors, at the time of overheating concerns,
There are phenomena such as the time average of the cooling water temperature becoming high and the frequency of the cooling water temperature becoming extremely high.These are reflected in the cooling water temperature history. Thought that it was possible to determine the presence or absence of a situation where overheating was likely to occur.

According to a second aspect of the present invention, there is provided an electric fan control device for an engine that controls an electric fan that blows air to a radiator, based on the result of the consideration. The electric fan control device for an engine according to the present invention is characterized in that the air blast control of the electric fan is performed according to the following formula, while the determination criterion is changed according to the history of the cooling water temperature.

A third aspect of the present invention is the electric fan control device for an engine according to the second aspect, further comprising a criterion changing means for fixing the criterion to the electric fan inoperative side for a certain period after the engine is started. An electric fan control device for an engine is provided.

According to the first aspect of the present invention, at the time of a warm restart, after the engine is started, the water pump drives the water pump to circulate the cooling water in the cooling system, and the temperature of the cooling water in the high temperature portion decreases. In this portion, the blower control of the electric fan based on the cooling water temperature is stopped for a predetermined period until the substantially average temperature of the cooling water of the entire cooling system can be detected, and during this time, the cooling water stays in the water jacket. The high-temperature cooling water passes around the water temperature sensor. Therefore, when the blower control of the electric fan is restarted, the substantially average temperature of the cooling water of the entire cooling system is detected, so that the occurrence of the rotation phenomenon immediately after the start and the generation of noise due to this are prevented. Further, unnecessary cooling of the cooling water is prevented, so that warm-up of the engine is promoted, and vaporization and atomization of the fuel are promoted.

According to the second invention, the history of the cooling water temperature is grasped,
From this history, the presence or absence of a situation where overheating is likely to occur is detected. Since the criterion can be changed, when a situation in which overheating easily occurs occurs, the criterion is set to the electric fan operating side, for example, the side where the electric fan is turned on / off at a lower reference temperature. By making the change, such a situation can be dealt with at an early stage, and occurrence of overheating can be prevented.

According to the third aspect, the same operation and effect as those of the second aspect can be obtained. Furthermore, at the time of a warm restart, the judgment criterion is fixed to a non-operating side of the electric fan, for example, a side where the electric fan is turned on / off at a higher reference temperature for a certain period of time, so that the high temperature staying in the water jacket is high. The occurrence of the rotation phenomenon immediately after the start of the electric fan by the cooling water and the generation of noise due to this phenomenon are prevented. Further, unnecessary cooling of the cooling water is prevented, and vaporization and atomization of the fuel are promoted.

[Examples] Examples of the present invention will be specifically described below.

As shown in FIG. 2, a water-cooled engine 3 having a cooling system C is provided at a substantially central portion of an engine room 2 of the automobile 1.
Is arranged. A radiator 4 forming a part of the cooling system C is disposed at a front end of the engine room 2, and an electric fan 5 for forcibly blowing air to the radiator 4 is disposed behind the radiator 4. .

As shown in FIG. 1, in the cooling system C, cooling water in a water jacket 6 formed in the engine 3 is sent to the radiator 4 through a cooling water discharge passage 7,
The cooling water cooled in the radiator 4 is supplied to a cooling water return passage 8.
The cooling water is returned to the inside of the water jacket 6 through the cooling water passage. In order to perform such cooling water circulation, the cooling water return passage 8 is provided with a water pump 9.
Is provided.

The cooling water discharge passage 7 is provided with a water temperature sensor 11 composed of a resistance type temperature sensor 11a. Further, when the cooling water temperature is low, the cooling water in the cooling water discharge passage 7 is bypassed to prevent the engine 3 from being overcooled.
A thermostat 13 is provided for flowing through the cooling water return passage 8 through the cooling water return passage 12.

Also, a battery is needed to supply power to various electrical devices.
15 are provided. The electric power of the battery 15 is supplied to various electric devices 18 via a first conductive line 17 provided with an ignition switch 16 and supplied to the electric fan 5 via a second conductive line 21 provided with a power transistor 19. And supplied to the control unit 23 via the third conducting wire 22.

The control unit 23 is connected to the resistance temperature detector 11a of the water temperature sensor 11 via the fourth conductor 24, and detects the electric resistance of the resistance temperature detector 11a, thereby detecting the electric resistance of the resistance water detector 11a. The temperature of the cooling water is detected. Further, the control unit 23 is connected to the base of the power transistor 19 via the fifth conductor 25, and depends on whether or not to apply a voltage to the base.
Is electrically connected or disconnected between the collector and the emitter, that is, the second conductive wire 21, and the electric fan 5 is turned on and off. Further, the control unit 23 is connected to a ground terminal (minus terminal) of the ignition switch 16 via a sixth conducting wire 26, and detects the voltage of the ground terminal of the ignition switch 16 so that the ignition switch 16 is turned on. On / off is detected.

The control unit 23 corresponds to the electric fan control device according to the first to third aspects, and controls the blower of the electric fan 5 using the cooling water temperature and the ON / OFF of the ignition switch as input information. However, the control method of the air blowing control by the control unit 23 will be described below with reference to the flowchart shown in FIG.

This air blowing control is generally performed by first performing cooling water temperature Tw and an ignition switch in steps # 1 to # 3.
16 on and off, and based on these, whether or not the engine has just started (within 10 seconds) and whether the engine 3
Is determined to be in a state of being easily overheated, and if it is immediately after the engine is started (within 10 seconds), the rotation phenomenon immediately after the start of the electric fan 5 as described in the application “Problems to be Solved by the Invention” In order to prevent the occurrence, the electric fan non-operation side routine of step # 4 to step # 8,
In other words, the routine is executed in which the reference temperature (judgment criterion) at which the electric fan 5 is to be turned on / off is higher, and when the engine is not immediately after starting (after 10 seconds) and when there is no fear of overheating, the fuel efficiency is improved. The above-described electric fan non-operation side routine (step # 4 to step # 8) is executed. On the other hand, when there is a concern about overheating, the electric fan operation side routine of step # 9 to step # 13 is performed to prevent the occurrence of overheating. That is, the configuration is such that the routine in which the reference temperature (judgment criterion) at which the electric fan 5 should be turned on / off is lower is executed.

In step # 1, the cooling water temperature Tw and the on / off state of the ignition switch 16 are read.

In step # 2, it is determined whether or not the time is within 10 seconds after the start of the engine. This determination is made by counting the elapsed time after the ignition switch 16 changes from off to on, that is, after the voltage of the ground terminal of the ignition switch 16 changes from 0 to positive, and determines whether this is within 10 seconds. This is done by comparing If it is determined in step # 2 that the time is within 10 seconds after starting the engine (YES), the occurrence of the rotation phenomenon immediately after starting as described in the application “Problems to be Solved by the Invention” is prevented. Then, an electric fan non-operation side routine (step # 4 to step # 8) described later is executed.

On the other hand, at step # 2, if it is determined that more than 10 seconds after starting the engine (NO), at step # 3, overheat determination reference temperature Tw ₅ the cooling water temperature Tw within the last 30 minutes are preset Is determined (see FIG. 4). In this embodiment, Tw> Tw within the past 30 minutes
_A score of ₅ is considered to be a concern for overheating. Specifically, the elapsed time from the last time when Tw> Tw ₅ is counted, and depending on whether or not this elapsed time is within 30 minutes, Tw> Tw ₅ within the past 30 minutes It is determined whether or not there is. The count is reset to a new count is started each time its Tw> Tw _5, when it is determined to be within 10 seconds after the engine is started at step # 2, was loaded into the round cooling Even if the water temperature Tw exceeds Tw ₅ , the count is not reset. In other words, this is to prevent the temperature of the high-temperature cooling water staying in the water jacket 6 from being used as a data for determining whether or not there is a situation in which overheating is likely to occur during a warm restart.

Here, since the control unit 23 is basically to continue the control even when the engine is stopped, in step # 3, regardless of the stop-operation of the engine 3, a Tw> Tw ₅ within the last 30 minutes It is determined whether there has been any event. Therefore, even when the engine 3 is once stopped, the history of the cooling water temperature before the engine is stopped, that is, information on overheating is inherited after the engine is restarted.

In step # 3, if it is judged that there may become Tw> Tw ₅ within the last 30 minutes (YES), ie if during overheating concerns, in order to prevent overheating, the electric describing later The fan operation side routine (step # 9 to step # 13) is executed.

On the other hand, at step # 3, if it is determined that never becomes Tw> Tw ₅ within the last 30 minutes (NO), because it is not a time overheating concerns, the relatively high maintained by fuel efficiency cooling water temperature In order to improve the performance, an electric fan non-operation side routine (step # 4 to step # 8) is executed.

Hereinafter, the electric fan non-operation side routine (steps # 4 to # 4)
Step # 8) will be described.

In step # 4, the cooling water temperature Tw is the electric fan operating temperature.
Whether or not the temperature is higher than Tw ₁ is compared. In step # 5, whether or not the cooling water temperature Tw is lower than the electric fan stop temperature Tw ₂ is compared. Based on these comparison results, whether Tw> Tw ₁ is satisfied. either a Tw <Tw _2, or whether it is Tw ₂ ≦ Tw ≦ Tw ₁ is determined. Incidentally, the magnitude relationship of Tw _1, Tw _2, Tw ₅ is as Figure 4.

If Tw> Tw ₁ (YES at step # 4), the step # 7 is executed unconditionally (including the continuation of on-state) the electric fan 5 is turned on.

If Tw <Tw ₂ (NO in step # 4 and step #
5; YES), step # 8 is executed unconditionally, and the electric fan 5 is turned off (including the continuation of the off state).

If _{Tw 2 ≦ Tw ≦ Tw 1 (} NO in NO and step # 5 in step # 4), further at step # 6, it is determined whether the electric fan 5 is turned on, the electric fan 5 is turned on (YES), Step # 7 is executed and the ON state is continued, and if the electric fan 5 is OFF (NO), Step # 8 is executed and the OFF state is continued. Therefore, when the cooling water temperature Tw rises from the low temperature state, Tw
> Electric fan 5 at the time point when Tw ₁ is turned on, when this after the coolant temperature Tw falls is, Tw <hysteresis occurs electric fan 5 such are turned off at time point when Tw _2, whereby hunting Is prevented.

When such an electric fan inoperative side routine is executed, is held in the cooling water temperature Tw is almost Tw ₂ ~Tw _1, thus the cooling water temperature Tw is kept relatively high temperature, the fuel efficiency is enhanced . Further, at the time of the warm start, the occurrence of the rotation phenomenon immediately after the start is prevented. After Step # 7 or Step # 8 is executed, the process returns to Step # 1.

Hereinafter, the electric fan operation side routine (Step # 9 to Step # 13) will be described.

This electric fan operation side routine has the same control logic as the electric fan non-operation side routine described above, and Steps # 9 to # 13 are executed in Step # 9, respectively.
Since steps 4 to # 8 are correspondingly described, the individual description of each step is omitted, and only the differences will be described below.

As shown in FIG. 4, in the electric fan operation routine, the electric fan operation temperature Tw ₃ and the electric fan stop temperature Tw ₄
Are the electric fan inoperative side routines respectively (Tw ₁ ,
Tw ₂ ) It is set to a lower value.

As a result, when the electric fan operation side routine is executed, the cooling water temperature Tw is generally held to Tw ₄ ~Tw _3, thus the cooling water temperature Tw is maintained at a relatively low temperature, when overheating concerns, overheating Can be prevented from occurring.

In the present embodiment, the occurrence of the rotation phenomenon immediately after the start is prevented by executing the electric fan operating side routine, but the electric fan 5 is forcibly turned on for a certain period (10 seconds) at the time of engine start. It may be turned off to prevent the occurrence of the rotation phenomenon immediately after starting. In this way, energy loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an engine and a cooling system of an automobile equipped with an electric fan control device according to the present invention. FIG. 2 is a perspective view of an engine room of an automobile provided with the electric fan control device according to the present invention. FIG. 3 is a flowchart showing a control method of air blowing control by the control unit. FIG. 4 is a diagram showing a relationship among an overheat determination reference temperature, an electric fan operating temperature, and an electric fan stop temperature in the air blowing control. C ... Cooling system, 1 ... Automobile, 2 ... Engine room, 3 ... Engine, 4 ... Radiator, 5 ... Electric fan, 6 ... Water jacket, 7 ... Cooling water discharge passage, 8 ... Cooling water return passage, 11… Water temperature sensor, 19 ……
Power transistor, 23 Control unit.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Seigo Sakai 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-61-252824 (JP, A) JP-A Sho 63-179120 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F01P 7/04 F02D 45/00

Claims (3)

(57) [Claims] 1. An electric fan control device for an engine for controlling an electric fan for blowing air to a radiator, comprising: a cooling water temperature detecting means for detecting a temperature of a cooling water in a portion of the cooling system which is heated by the heat capacity of the engine. While controlling the air blowing of the electric fan in accordance with the output value of the cooling water temperature detection means and at least a determination criterion based on at least the cooling water temperature, the cooling water flows through the cooling system by driving the water pump after the engine is started. The air flow control is stopped for a predetermined period of time until the temperature of the cooling water circulates and becomes high and the approximate average temperature of the cooling water of the entire cooling system can be detected in this part. An electric fan control device for an engine. 2. An electric fan control device for an engine for controlling an electric fan that blows air to a radiator, wherein the fan control of the electric fan is performed in accordance with a criterion preset based on at least the temperature of the cooling water, while a history of the cooling water temperature is controlled. An electric fan control device for an engine, wherein the criterion is changed according to the condition. 3. The electric fan control device for an engine according to claim 2, further comprising a criterion changing means for fixing the criterion to a non-operating side of the electric fan for a certain period after starting the engine. An electric fan control device for an engine.