JPS6337248B2 - - 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.

However, 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. The amount of circulating water (water pump rotation speed) is set to ensure sufficient cooling capacity to prevent overheating even when the outside temperature is high and the combustion heat of the engine is high. be. Therefore, when the engine temperature is lower than the set value in cold regions, etc., the amount of cooling water supplied may become excessive, resulting in supercooling, which increases the warm-up time, and requires unnecessary water pump operation. The drive results in a loss of engine output and impedes improvements in fuel efficiency.

Therefore, as shown in Japanese Patent Application Laid-Open No. 53-136144, the water pump that supplies cooling water to the cooling water passage can be driven and controlled independently of the engine rotation, and the engine temperature can also be detected. , the rotation speed of the water pump is controlled according to the engine temperature, and when the engine temperature is low, the amount of cooling water supplied by the water pump is reduced or stopped,
Engines have been proposed that improve fuel efficiency and shorten warm-up time by reducing engine output loss.

However, when controlling the rotational speed of the water pump in accordance with the engine temperature as in the conventional example, there is a risk that overheating may occur in extremely localized areas depending on the position at which the engine temperature is detected. In other words, the engine temperature fluctuates the most and reaches the highest temperature near the combustion chamber (especially at the exhaust port) where high-temperature combustion gas comes into contact with the engine.
When the engine temperature is detected from the cooling water temperature in the water jacket in the cylinder block, there is a long delay before the detected engine temperature rises even if the high-temperature section reaches a high temperature. The increase in rotational speed is delayed, the cooling capacity is low, and the high-temperature section becomes extremely overheated exceeding an allowable value, resulting in a problem that adversely affects durability and the like.

In view of this, the present invention detects the temperature near the combustion chamber of the engine to control the drive of the water pump, thereby preventing the occurrence of local overheating and improving the output loss of the engine as a whole. ,
The purpose is to improve warm-up performance.

That is, the engine water pump control device of the present invention includes a water pump for circulating cooling water inside the engine, a drive device that can drive and control the water pump independently with respect to engine rotation, and a water pump for circulating cooling water inside the engine. The combustion chamber is characterized by comprising a temperature sensor provided near the combustion chamber to detect the temperature near the combustion chamber, and a control circuit that receives the output of the temperature sensor and controls the drive device.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an engine equipped with a cylinder head 2 and a cylinder block 3, 4 is a combustion chamber surrounded by the cylinder head 2 and a piston 5, and 6 is connected to the combustion chamber 4 and connected to an intake valve 7. An intake port 8 is opened and closed by an exhaust valve 9, and 8 is an exhaust port which also communicates with the combustion chamber 4 and is opened and closed by an exhaust valve 9.

Reference numeral 10 denotes a cooling water passage constituted by a water jacket provided in the cylinder head 2 and cylinder block 3, and the cooling water passage 10 is connected to a radiator (not shown) disposed outside the engine 1. )It is connected to the.

The cooling water passage 10 is equipped with a water pump 1 for supplying cooling water and circulating it inside the engine 1.
1 is interposed, and the water pump 11 is configured to be able to be driven and controlled independently of engine rotation by a drive device 12, and this drive device 12
is controlled in conjunction with the control circuit 13, and the rotational speed of the water pump 11 is controlled.

That is, the water pump 11 is connected to an electric motor 15 via a transmission belt 14, and the operation of the electric motor 15 is controlled by a control circuit 13.
controlled by signals from

A temperature sensor 16 is provided near the combustion chamber 4 of the engine 1 and detects the engine temperature near the combustion chamber 4. The output of the temperature sensor 16 is input to the control circuit 13.
controls the drive device 12 in response to the output of this temperature sensor 16. When the engine temperature is low, the rotation speed of the water pump 11 is reduced or stopped, and when the engine temperature rises, the rotation speed of the water pump 11 is decreased. It is designed to either raise or start driving.

In the illustrated case, the temperature sensor 16 is mounted on the cylinder head 2 of the engine 1 and is configured to detect the temperature near the combustion chamber 4 from the wall temperature between the intake port 6 and the exhaust port 8.

The mounting position of the temperature sensor 16 is such that the detected wall temperature increases as it approaches the exhaust port 8, and the temperature sensor 16 is inserted into the cooling water passage 10 to detect combustion from the cooling water temperature. The temperature near the chamber 4 may also be detected. that time,
Cooling water temperature detection is less sensitive to temperature changes than wall temperature detection.

FIG. 2 shows an example of the control circuit 13, in which the output signal of the temperature sensor 16 is input to a temperature detection circuit 17 to detect the engine temperature.
The output signal of this temperature detection circuit 17 is input to an output current calculation circuit 18. This output current calculation circuit 1
8 calculates an output current to drive the electric motor 15 at a predetermined rotation speed in accordance with the magnitude of the engine temperature signal from the temperature detection circuit 17, and the output signal is sent to the drive device 12 by the current control circuit 19. Output.

The output current from the current control circuit 19 is applied to a relay 20 that starts and stops the electric motor 15, and is also applied to the base of a transistor 22 connected to a rotation control coil 21 of the electric motor 15. That is, when the output current becomes larger than a predetermined value, the contacts of the relay 20 are closed to start the electric motor 15, while a rotation control current corresponding to the output current flows to the rotation control coil 21 due to the action of the transistor 22, and the electric motor is activated. It is configured to control the rotation speed of the motor 15, that is, the rotation speed of the water pump 11, to a predetermined rotation speed.

In the above embodiment, the cooling water passage 10 is one system, but this cooling water passage is divided into a first cooling water passage that cools the high temperature part (cylinder head 2) of the engine 1 and a low temperature part (the cylinder head 2) 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 3).

Further, in the above embodiment, an example was shown in which the electric motor 15 was used as the drive device 12 of the water pump 11, but the present invention is not limited to this. For example, the water pump is connected to the output shaft of the engine. The driving device may be configured to drive in conjunction with each other via a variable pulley mechanism, and may be configured to control the gear ratio of this variable pulley mechanism. It is also possible to use a driving device that drives in conjunction with each other.

Therefore, according to the present invention as described above, the rotation speed of the water pump is controlled according to the engine temperature,
This eliminates unnecessary driving of the water pump, improves engine output loss, improves fuel efficiency and warm-up performance, and detects engine temperature near the combustion chamber, where the temperature is highest. This makes it possible to prevent the occurrence of localized overheating caused by detection delays.

[Brief explanation of the drawing]

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. 1...Engine, 2...Cylinder head, 3...
... Cylinder block, 4 ... Combustion chamber, 6 ... Intake port, 8 ... Exhaust port, 10 ... Cooling water passage, 11 ... Water pump, 12 ... Drive device, 13 ... Control circuit, 15 ... electric motor, 1
6...Temperature sensor.

Claims (1)

[Claims] 1. A water pump for circulating cooling water inside the engine, a drive device that can drive and control the water pump independently of engine rotation,
A water pump control device for an engine, comprising: a temperature sensor provided near the combustion chamber of the engine to detect the temperature near the combustion chamber; and a control circuit that receives the output of the temperature sensor and controls the drive device. .