JP2004084573A - Fan clutch control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fan clutch control device to economize fuel consumption of an engine and to increase this economical effect without using expensive components, by providing a fan clutch in an engine cooling fan and stopping the rotation of the cooling fan when the temperature of cooling water is low. <P>SOLUTION: A rotation sensor is provided on the fan side of the fan clutch, and when the fan clutch becomes slippery, warning is given step by step to urge its maintenance. Thereby, a serious failure that the temperature of the engine abnormally rises due to the failure of the fan clutch is avoided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICATION This invention is utilized for control of the engine cooling device of a motor vehicle. The present invention relates to a device for controlling the rotation of an engine cooling fan by a fan clutch to economize energy consumed by the cooling fan. The present invention relates to a device for generating an alarm to prompt a corresponding maintenance before a serious failure occurs in a cooling device due to a failure of a fan clutch.
[0002]
[Prior art]
A device that circulates cooling water of an engine through a radiator and cools the radiator with a cooling fan that is driven to rotate by a rotation shaft of the engine is widely used. Conventionally, this cooling fan is directly connected to the engine rotation shaft, or a pulley is provided on the rotation shaft of the cooling fan, and a fan belt is stretched over the pulley provided on the engine rotation shaft, so that the cooling fan Is configured to be rotationally driven in accordance with Such a device has a structure in which the cooling fan rotates steadily with the rotation of the engine from a sieve.In recent years, however, a fan clutch is provided between a rotating shaft for driving the cooling fan and a rotating shaft of the cooling fan. The device has become known. By controlling the opening and closing of the fan clutch, the rotation and stop of the cooling fan can be controlled. This structure is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-119455.
[0003]
In the device having this structure, when the temperature of the engine cooling water is low, the rotation of the cooling fan for cooling the radiator is stopped, so that useless energy consumption can be prevented. That is, the temperature of the engine cooling water is monitored, and when the temperature of the engine cooling water is sufficiently low, the rotation of the cooling fan is stopped by releasing the fan clutch. By utilizing the device that automatically controls the rotation of the cooling fan with the clutch as described above, it is possible to reduce wasteful energy consumption when the temperature of the engine cooling water is low. Test results show that in commercial vehicles such as heavy trucks and buses, the use of such a device can improve the fuel consumption of the engine by 2-3% under average vehicle usage. It has been reported.
[0004]
[Problems to be solved by the invention]
Designing such a device requires the use of reasonably reliable components for the fan clutch. If a malfunction occurs in the state where the fan clutch is engaged, the effect of improving the fuel consumption in a state where the cooling water is low is lost, but a failure that the vehicle cannot be run does not occur. However, a failure that cannot be engaged in a state where the fan clutch is released may increase the temperature of the engine cooling water and cause a road failure of the vehicle. The most likely failure of the fan clutch is a failure in which the rotational power is not effectively transmitted through the clutch due to wear of the contact surface of the clutch or deterioration or leakage of the fluid (in the case of an oil clutch). is there.
[0005]
The fan clutch is a mechanical component having a movable mechanism, and if all vehicles are designed to have no failure over the entire life of the vehicle, they become extremely expensive components. It is not possible to design the life of the fan clutch beyond the life of the vehicle for all uses. Since the economic effect of fuel consumption by using a fan clutch is at most a few percent as described above, it is irrational and meaningless to design using expensive parts that can cover this economic effect. Disappears.
[0006]
Generally, the failure of the clutch is such that the transmission of power is suddenly impossible and the failure of the clutch is extremely rare, and a slippery state occurs in the clutch, which gradually expands to the point where power transmission becomes impossible. That is, in the case of a mechanical contact type clutch, mechanical wear of the contact surface occurs, and this gradually increases. In the case of a fluid clutch, the clutch becomes slippery due to deterioration of the clutch oil or slight leakage, etc., and this phenomenon gradually increases, and power transmission becomes impossible.
[0007]
The present invention has been made in such a background, and an object of the present invention is to provide a cooling fan clutch control device that does not cause a serious vehicle failure due to a failure of a fan clutch. SUMMARY OF THE INVENTION It is an object of the present invention to provide a device capable of inexpensively and reasonably improving the substantial reliability of a fan clutch. The present invention relates to a control device capable of properly detecting a malfunction in which a fan clutch becomes slippery before it leads to a fatal malfunction, prompting maintenance and maintenance, and preventing a serious malfunction due to the fan clutch. The purpose is to provide.
[0008]
[Means for Solving the Problems]
According to the present invention, a sensor for detecting rotation is provided on the cooling fan side of a fan clutch provided in a passage for transmitting rotational power to the cooling fan, and the rotation detected by this sensor is corresponding to the rotation of the engine rotation shaft. The greatest feature is that when a slip condition occurs, a warning is issued to prompt the maintenance of the fan clutch.
[0009]
That is, the present invention includes a fan clutch (2) provided in a rotation transmitting means between an engine cooling fan (1) and an engine rotation shaft, and a control circuit (3) for controlling opening and closing of the fan clutch. A sensor for detecting rotation of the fan clutch on the fan side, and means for comparing and monitoring a rotation signal detected by the sensor and a rotation signal of the engine rotation shaft. And means for issuing an alarm when the difference between the two rotation signals exceeds a predetermined range. The numerals in the parentheses are reference numerals for the drawings of the embodiments described later.
[0010]
With this configuration, when the fan clutch becomes slippery due to wear of the fan clutch, oil deterioration or leakage, etc., an appropriate alarm is issued and this fan clutch is repaired. Can be. Therefore, it is possible to prevent the failure from proceeding without noticing the failure of the fan clutch and causing the temperature of the cooling water to suddenly increase to cause a state in which the vehicle cannot travel. With such a configuration, a relatively inexpensive fan clutch can be used, and a reasonable economic effect on the fuel consumption by using the fan clutch can be obtained.
[0011]
The means for comparing and monitoring the two rotation signals can evaluate the difference between the two rotation signals within a predetermined time and detect that the fan clutch has become slippery. However, not only those that evaluate the difference between the two rotation signals, those that evaluate the ratio of the two rotation signals within a predetermined time, or those that perform and evaluate a function operation for comparing the two rotation signals, The present invention can be implemented with various configurations.
[0012]
Preferably, the control circuit is a program control circuit, and the means for comparing and monitoring is provided in the control circuit. This control circuit can be configured by adding software inside the engine ECU. With this configuration, the addition of hardware is limited to one rotation sensor and small parts around the rotation sensor, and in other cases, the present invention can be implemented by partially changing the software of the engine ECU.
[0013]
Preferably, the control circuit includes a unit for recording the occurrence of the alarm. In the initial stage when the fan clutch is worn, the fan clutch generally slips occasionally. Then, as the wear progresses, slippage occurs continuously. Therefore, an alarm indicating that a slip has occurred in the fan clutch is temporarily recorded automatically in the memory of the control circuit, and this record is read out during maintenance and maintenance. You can know that it is in the state. According to this record, appropriate measures such as replacement or repair of the fan clutch can be taken.
[0014]
When the slippage of the fan clutch occurs, the detection of the alarm can be set in two stages. The control circuit includes means for automatically recording the occurrence of the alarm for the first-stage alarm, and means for displaying the alarm on the driver's seat for the second-stage alarm. It can be. With this configuration, in the first stage, that is, when the fan clutch has a slight slip, only the alarm is recorded, and in the second stage, that is, when the fan clutch has a correspondingly large slip, the alarm is not recorded. It can be configured to facilitate repair and maintenance. As a result, a serious failure due to a failure of the fan clutch can be properly avoided, and parts replacement and work man-hours associated with repair and maintenance of the fan clutch are not excessively increased.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The apparatus of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a block diagram of the apparatus according to the embodiment of the present invention. FIG. 2 is a main part flowchart for explaining the operation of the control circuit of the apparatus according to the embodiment of the present invention.
[0016]
The cooling fan 1 of the engine 10 cools cooling water circulating through a radiator (not shown). The cooling fan 1 is mechanically connected to a rotating shaft of the engine 10 and is driven to rotate. In this device, a fan clutch 2 is provided on a rotation drive shaft of the cooling fan 1. When the temperature of the cooling water is low and it is not necessary to rotate the cooling fan 1, the fan clutch 2 is opened and the rotation of the cooling fan 1 is started. Is configured to be stopped. The fan clutch 2 is a fluid clutch (or a mechanical clutch), and the opening and closing control of the fan clutch 2 is performed by an electric signal.
[0017]
The fuel supply and rotation speed of the engine 10 are controlled by an engine ECU (Electronic Control Unit) 5. The engine ECU 5 is a program control circuit, and is configured by installing software on a device including a large number of semiconductor switch elements. The control inputs of the engine ECU 5 are operation information of an accelerator pedal in a driver's seat, rotation information of an engine, temperature information of cooling water, state information of a clutch and a transmission, and the like. The control output of the engine ECU 5 is supplied to the engine 10 via an input / output interface (I / O), and the fuel flow and the air inflow thereof are adjusted and controlled. For these, well-known techniques can be used, and therefore detailed descriptions in the drawings of this embodiment are omitted.
[0018]
An electric signal for controlling the fan clutch 2 is generated from a control circuit 3 set inside the engine ECU 5. Specifically, the control circuit 3 is constructed by adding software inside the engine ECU 5 and providing corresponding connection hardware at an input / output interface (I / O) of the engine ECU 5. That is, the output of the sensor 4 for detecting the rotation of the cooling fan 1 is taken into the control circuit 3 via the input / output interface, and the control output of the control circuit 3 is supplied to the fan clutch 2 via the input / output interface. Open / close control.
[0019]
A display 6 is connected to the engine ECU 5 via an input / output interface. The display 6 is an optical display provided in the driver's seat, and provides a display for urging the driver to check and maintain the fan clutch.
[0020]
The engine ECU 5 is provided with a connection terminal 7 via an input / output interface. The connection terminal 7 is a terminal for connecting an external device for inspection and maintenance arranged in a maintenance shop. By connecting an external device, the data recorded in the engine ECU 5 can be read, and by operating the external device, the setting parameters of the engine ECU 5 can be partially changed. The present invention uses this external device to read the slip amount of the fan clutch recorded in the control circuit 3 and use this as a reference for maintenance.
[0021]
Explaining the operation of the device configured as described above, when the engine 10 is started, the engine ECU 5 starts up, takes in input information, and starts control. The control circuit 3 of the present invention controls the opening and closing of the fan clutch 2 according to the input coolant temperature information. That is, when the temperature of the cooling water is lower than the set value, the cooling fan 1 does not need to be rotated, and the fan clutch 2 is controlled to the open state. When the temperature of the cooling water becomes higher than the set value, the fan clutch 2 is controlled to the connected state, the cooling fan 1 is rotated, and cooling air is sent to a radiator (not shown). When the temperature of the cooling water becomes low due to the cooling air, the fan clutch 2 is controlled to the released state again to stop the rotation of the cooling fan 1. By controlling the rotation of the cooling fan 1 only for a necessary period in this way, the rotational power for rotating the cooling fan 1, that is, the fuel consumption of the engine 10 can be reduced.
[0022]
Here, the characteristic control operation of the present invention will be described with reference to the flowchart shown in FIG. When the rotation of the engine 10 is stable, the vehicle is not at a standstill, and the state of the fan clutch 2 is stable after t seconds (for example, t = 3 seconds) have elapsed since the control of the fan clutch 2 Next, the fan rotation and the engine rotation will be compared. The state where the rotation of the engine 10 is stable is, for example, assumed that the fluctuation of the engine rotation speed is within ± 10% for 3 seconds.
[0023]
The comparison between the fan rotation and the engine rotation is performed so that the occurrence of slippage in the fan clutch 2 can be detected in two stages. As an example, a two-stage determination is made as to whether the ratio of the rotation speeds of the engine and the cooling fan is 90% or more of a normal value, or less than 90% and further less than 50%. That is, the ratio of the engine rotation speed to the fan rotation speed when the fan clutch 2 is in a completely engaged state and there is no slippage between the two is set as a constant, and the detected ratio between the two rotation speeds is determined by this constant. If it is 90% or more of the constant, it is determined to be normal. A first stage alarm output is generated when the detected ratio falls below 90% of this constant. Then, the alarm output of the first stage is recorded in a diagnostic memory inside the engine ECU 5. Further, when the ratio between the detected rotational speeds is less than 50% of the above constant, this is set as a second-stage warning, which is displayed on the driver's seat to prompt prompt maintenance and maintenance.
[0024]
The first-stage alarm is recorded in the memory of the engine ECU 5 and is read out at the time of maintenance and maintenance of the vehicle. Then, according to this record, the condition of the fan clutch 2 is checked, and necessary repairs or parts replacement are performed. The second-stage warning is to warn the driver that it is necessary to perform maintenance on the fan clutch 2. When this display is lit, the driver can perform appropriate maintenance before the engine temperature rises and the vehicle cannot travel.
[0025]
【The invention's effect】
According to the present invention, even if a malfunction occurs in the fan clutch, the malfunction can be repaired and maintained before the malfunction causes a serious vehicle failure. With this configuration, it is possible to inexpensively and rationally improve the substantial reliability of the fan clutch without excessively increasing the quality of the fan clutch. By providing a two-stage warning that the fan clutch is slippery, the fan clutch is not needlessly maintained, and its substantial reliability can be improved economically.
[0026]
[Brief description of the drawings]
FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart of a main part of a control circuit of the apparatus according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cooling fan 2 Fan clutch 3 Control circuit 4 Sensor 5 Engine ECU (Electronic Control Unit)
6 Display 7 Connection terminal 10 Engine

Claims (3)

In a fan clutch control device including a fan clutch provided in a rotation transmission unit between an engine cooling fan and an engine rotation shaft, and a control circuit for controlling opening and closing of the fan clutch,
A sensor for detecting the rotation of the fan clutch on the fan side, means for comparing and monitoring a rotation signal detected by the sensor and a rotation signal of the engine rotation shaft, and a difference between the two rotation signals exceeding a predetermined range. Means for generating an alarm when the fan clutch is activated. 2. The fan clutch control device according to claim 1, wherein said control circuit is a program control circuit, and said means for comparing and monitoring is provided in said control circuit. The predetermined range is set in two stages, and the control circuit includes means for automatically recording the occurrence of the alarm for the first stage alarm, and operates the alarm for the second stage alarm. 3. The control device for a fan clutch according to claim 2, further comprising means for displaying the information on a seat.

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