JPS6349047B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water pump control device for an engine.

Generally, in an engine, a water jacket is provided on the cylinder block and the cylinder head, and cooling water is circulated within the water jacket by driving a water pump to cool each part.

In the above-mentioned water pump, the rotation of the engine's crankshaft is usually transmitted through a belt through a pulley, and the water pump is constantly driven to rotate while the engine is rotating to circulate cooling water. There is a problem that overheating occurs due to an insufficient amount of cooling water being fed, or overcooling occurs due to an excessive amount of cooling water being fed.

Therefore, as shown in Japanese Patent Application Laid-Open No. 53-136144, the water pump can be driven and controlled independently of the engine rotation, and the rotation speed of the water pump is controlled depending on, for example, the engine temperature. A system has been proposed that aims to maintain the engine temperature at a stable temperature and obtain a good cooling function.

However, in the case where the water pump rotation speed is controlled according to the operating state of the engine as described above, if the water pump driving device, various sensors that detect the operating state of the engine, and the control device fail, the water pump will not be able to rotate at a predetermined speed. The problem is that the cooling capacity decreases, causing the engine temperature, that is, the cooling water temperature, to rise abnormally, resulting in an overheating state.

Also, for example, when the cooling water level decreases due to a cooling water leak, or when the radiator fan does not operate,
When knocking occurs for a long period of time, the engine temperature rises rapidly, and the cooling capacity does not increase accordingly, leading to the risk of overheating as described above.

In view of this, the present invention connects the water pump to the output shaft of the engine using a connecting device to drive the water pump in the event of an abnormality such as a failure of the water pump drive system or control system, and the engine is heated to an abnormally high temperature. The aim is to prevent this from happening.

That is, the water pump control device for an engine of the present invention includes a drive device that can drive and control the water pump independently of the engine rotation, and a drive device that controls the water pump so that the water pump rotation speed reaches a predetermined value in response to outputs from various sensors. The engine is characterized in that it includes a control device that controls the drive device, and a connection device that operates in the event of an abnormality and connects the water pump to the engine output shaft.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an engine, 2 is a cooling water passage provided with a radiator 3, and the cooling water passage 2 is connected to a water jacket formed in a cylinder block 4 of the engine 1 from downstream of the radiator 3, and It passes through a water jacket formed in the cylinder head 5 and is configured to communicate with the upstream side of the radiator 3 via a thermostat 6.

A water pump 7 for feeding cooling water is interposed in the cooling water passage 2, and the water pump 7 is configured to be able to be driven and controlled independently of engine rotation by a drive device 8, and this drive device 8 is controlled in conjunction with a control device 9, and the rotational speed of the water pump 7 is controlled.

That is, the water pump 7 is connected to an electric motor 11 via a transmission belt 10, and the operation of the electric motor 11 is controlled by signals from a control device 9.

Further, 12 is a temperature sensor that detects the engine temperature, and the output of the temperature sensor 12 is inputted to the control device 9, and the control device 9 receives the output of the temperature sensor 12 and controls the drive device 8. When the engine temperature is low, the rotation speed of the water pump 7 is reduced or stopped, and when the engine temperature rises, the water pump 7 is
increase the rotation speed or start driving,
The rotation speed is controlled to a predetermined number.

In the illustrated case, the temperature sensor 12 is mounted on the cylinder head 5 of the engine 1 and is configured to detect the engine temperature from the cooling water temperature or wall temperature of the high temperature portion.

On the other hand, 13 is a connection device for connecting the water pump 7 to the output shaft 14 of the engine 1,
When the electromagnetic clutch 15 is operated, the rotation of the output shaft 14 is transmitted to the water pump 7 via the transmission belt 16, and the electromagnetic clutch 15 of the connecting device 13 is operated and controlled by the control device 9. It is activated to the connected state in the event of an abnormality.

In this embodiment, the connection device 13 includes:
Either the output of the temperature sensor 12 is not input to the control device 9 due to disconnection of the coupler, disconnection, etc., or the rotation signal of the electric motor 11 is input to the control device 9 to detect the actual rotation speed of the electric motor 11. The electric motor 11 is configured to operate in the event of an abnormality in which the rotational speed of the electric motor 11 is lower than the rotational speed set by the control device 9 by more than a permissible value or has stopped in accordance with the output of the temperature sensor 12.

Further, 17 is an alarm device that is activated by the control device 9 when the connection device 13 is activated.

Furthermore, 18 is a heating device (radiator) branch-connected to a part of the cooling water passage 2, and the amount of cooling water supplied from the cooling water passage 2 to the heating device 18 is adjusted by an on-off valve 19. In addition, 20 is a heating device 18
It is a ventilation fan.

Note that the number of rotations when the water pump 7 is driven by the operation of the connection device 13 is set to be higher than the number of rotations caused by the drive device 8.

FIG. 2 shows an example of a control system for the water pump 7 and the connecting device 13, in which the output signal of the temperature sensor 12 is input to a temperature detection circuit 21 to detect the engine temperature. The output signal is input to the output current calculation circuit 22. The output current calculation circuit 22 calculates an output current to drive the electric motor 11 at a predetermined rotation speed in accordance with the magnitude of the engine temperature signal from the temperature detection circuit 21, and drives the electric motor 11 via the current control circuit 23. It is output to device 8.

The output current from the current control circuit 23 is applied to a relay 24 that starts and stops the electric motor 11, and is also applied to the base of a transistor 26 connected to a rotation control coil 25 of the electric motor 11. That is, when the output current becomes larger than a predetermined value, the contacts of the relay 24 are closed to start the electric motor 11, while a rotation control current corresponding to the output current flows to the rotation control coil 25 due to the action of the transistor 26, and the electric motor is activated. It is configured to control the rotational speed of the motor 11, that is, the rotational speed of the water pump 7, to a predetermined rotational speed.

Further, the temperature signal of the temperature detection circuit 21 is
and are input to the second comparison circuits 27 and 28, respectively, and are input to the first and second reference level transmission circuits 30,
31. The first reference signal of the first reference level transmitting circuit 30 corresponds to the upper limit temperature of the normal engine temperature range, and when the output signal from the temperature detection circuit 21 is larger than the first reference signal, for example, When the engine temperature becomes abnormally higher than the stable temperature due to water loss or knocking, the first
Comparison circuit 27 outputs a signal to OR circuit 32.
On the other hand, the second reference signal of the second reference level transmitting circuit 31 corresponds to the lower limit temperature of the normal engine temperature range, and when the output signal from the temperature detection circuit 21 is smaller than the second reference signal, that is,
For example, when the coupler of the temperature sensor 12 is disconnected and its output signal is not input, the second comparison circuit 28
outputs a signal to the OR circuit 32.

Further, the rotation pulse signal from the electric motor 11 is input to a waveform shaping circuit 33 to form a rectangular wave, and then integrated by an integration circuit 34 to detect the motor rotation speed, and the output signal of this integration circuit 34 is sent to a gain adjustment circuit. 35. This gain adjustment circuit 3
5 increases the motor rotation signal from the integrating circuit 34 by an amount corresponding to an allowable rotation reduction value that takes into account errors in the motor rotation speed and the like. The above gain adjustment circuit 35
The output signal is input to the third comparison circuit 29 and compared with the output signal from the output current calculation circuit 22, and the output signal from the gain adjustment circuit 35 is smaller than the output signal from the output current calculation circuit 22. In other words, when the actual rotation speed of the electric motor 11 decreases beyond the allowable value with respect to the set rotation speed, the third comparison circuit 29 outputs a signal to the OR circuit 32.

The above OR circuit 32 has a first, second or third
The connection device 13 operates when a signal is input from at least one of the comparison circuits 27, 28, and 29.
outputs an operating signal to connect the electromagnetic clutch 15, and connects the water pump 7 to the output shaft 14 of the engine 1.
At the same time, an alarm device 17 such as an alarm lamp is activated.

Incidentally, the timing at which the connection device 13 is activated is not limited to the above embodiment, but may occur if the drive device 8, the temperature sensor 12, or the control device 9 that controls the rotation of the water pump 7 breaks down and the water Abnormalities such as when the pump 7 cannot be driven at the specified rotation speed, or when the engine temperature becomes higher than the stable temperature by more than the set value due to a lack of cooling water, a failure of the radiator fan, occurrence of knocking, etc. It is intended to be activated at times.

Furthermore, although the above embodiment has been described in which there is one system of cooling water passages 2, this cooling water passage is divided into a first cooling water passage that cools the high temperature section (cylinder head 5) of the engine 1 and a low temperature section (the cylinder head 5) of the engine 1. It is also applicable to a configuration in which the system is branched into two systems including a second cooling water passage for cooling the cylinder block 4).

Further, as signals for controlling the rotation speed of the water pump 7, in addition to signals from the temperature sensor 12, various sensors that detect the operating state of the engine such as an engine rotation speed sensor, an intake negative pressure sensor, and an acceleration sensor can be used. signals can be used.

Therefore, according to the present invention as described above, the water pump can be driven and controlled independently of the engine rotation, and the water pump rotation speed is controlled to a predetermined value according to the operating state of the engine. In addition, when an overheating condition is induced, such as when a drive unit, sensor, or control device fails, or when an abnormality occurs, such as when the engine temperature rises abnormally, the water pump is It has the advantage that it can be connected to the output shaft of the engine to reliably drive at a relatively high rotational speed, suppress the rise in engine temperature, prevent the occurrence of an abnormally high temperature state, and protect the engine.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention, with FIG. 1 being an explanatory diagram showing the overall configuration, and FIG. 2 being a control circuit diagram showing an example of a control system. DESCRIPTION OF SYMBOLS 1... Engine, 2... Cooling water passage, 3... Radiator, 6... Thermostat, 7... Water pump, 8... Drive device, 9... Control device, 1
0...Transmission belt, 11...Electric motor, 12...
... Temperature sensor, 13 ... Connection device, 14 ... Output shaft, 15 ... Electromagnetic clutch, 16 ... Transmission belt, 17 ... Alarm device.

Claims (1)

[Scope of Claims] 1. A drive device that can drive and control the water pump independently of engine rotation, and control that controls the drive device so that the water pump rotation speed reaches a predetermined value in response to outputs from various sensors. 1. A water pump control device for an engine, comprising: a water pump control device; and a connection device that operates in the event of an abnormality and connects the water pump to an engine output shaft. 2. The engine water pump control device according to claim 1, wherein the connection device is activated when the drive device fails. 3. The engine water pump control device according to claim 1, wherein the connecting device is activated when the sensor fails. 4. The engine water pump control device according to claim 1, wherein the connection device is activated when the control device fails. 5. The engine water pump control device according to claim 1, wherein the connecting device is activated when the engine temperature is higher than the stable temperature by a set value or more.