JPH06323137A - Engine cooling water temperature control device - Google Patents

Abstract

PURPOSE:To always maintain a good combustion condition by providing a control means for adjusting a supply amount of cooling water to a radiator through a cooling water supply amount changing means in order to hold a cooling water temperature to an objective value. CONSTITUTION:A valve device 3, which is a cooling water supply amount changing means, is provided in a part bent at a right angle of a cooling water flow path 42. In a flow path wall in the downstream of a valve element 2, a temperature sensor 11 for detecting a cooling water temperature is provided, and a signal of the temperature sensor 11 is input to a control circuit 1. In the control circuit 1, an operation condition of an engine is decided, and also based on a detection signal of alcohol concentration in fuel, a rotation signal to a motor is output. The control circuit 1 reads the alcohol concentration, and a target value of engine cooling water temperature is set in accordance with the alcohol concentration. The rotation signal is output to the motor 7 to change a position of the valve element 2 so that the cooling water temperature obtains the objective temperature. Thus, a good combustion condition of the engine can be always maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling water temperature control device, and more particularly to a cooling water temperature control device suitable for use in an engine using a mixed fuel.

[0002]

2. Description of the Related Art Conventionally, a cooling water temperature of an engine is controlled by a thermostat 82 provided in a cooling water circulation path as shown in FIG. That is, the cooling water that has cooled each cylinder through the water jacket 81 of the engine 8 and heated itself reaches the radiator 83 via the thermostat 82 as shown by the arrow in the figure, is cooled there, and is cooled by the water pump 84. It is returned to the engine 8 again.

A wax type is often used as the thermostat 82. This is because the valve element opens according to the cooling water temperature due to the thermal expansion of the built-in wax.
While the cooling water temperature is low, it is closed to bypass the cooling water without flowing to the radiator 83, and when the cooling water temperature rises, it is gradually opened to increase the cooling water circulation amount to the radiator 83 and maintain the cooling water temperature at a desired value. is doing.

[0004]

By the way, in recent years, for the purpose of improving exhaust emission and removing petroleum, it has been attempted to use a mixed fuel obtained by mixing a certain amount of alcohol or the like with gasoline. In this case, alcohol has a higher latent heat of vaporization than gasoline, so when the engine cooling water temperature is set on the assumption that gasoline is used, the wall temperature of the combustion chamber will drop excessively, the combustion state will deteriorate, and rather exhaust emission There is a problem that the fuel efficiency is deteriorated as the fuel consumption decreases.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a cooling water temperature control device capable of setting an optimum cooling water temperature in accordance with the mixture concentration of fuel.

[0006]

The configuration of the present invention will be described with reference to FIG. 1. Means for knowing the mixed concentration of fuel components of an engine and setting a target temperature of engine cooling water according to the concentration, and an external signal. The means for changing the engine cooling water supply amount to the radiator according to the above, and the control means for outputting the external signal to the cooling water supply amount changing means in order to match the engine cooling water to the target temperature. ing.

[0007]

In the above structure, the target temperature determined in advance is selected and set according to the thermal characteristics such as latent heat of vaporization based on the mixed concentration of the fuel components of the engine. Then, the control means adjusts the cooling water supply amount to the radiator through the cooling water supply amount changing means, so that the cooling water temperature is maintained at the target temperature.

Thus, the optimum cooling water temperature is realized according to the engine used and the thermal characteristics of the fuel, and a good combustion state is always maintained without causing overcooling of the engine combustion chamber wall, resulting in deterioration of exhaust emission and the like. Is avoided.

[0009]

EXAMPLE In FIG. 2, a cooling water passage 41 extending from an engine to a radiator and a cooling water passage 42 extending from a radiator to a water pump (further, an engine) are provided, and a cooling water passage 42 is bent at a right angle. A valve device 3 as a water supply amount changing means is provided. The valve device 3 has the columnar valve body 2 arranged in the frame body 33 fixed to the flow path wall.
The valve body 2 has a flange-shaped valve plate 21 and a frame 33 on the outer periphery of the upper end thereof.
It is supported by a coil spring 51 provided between the lower end and the lower end of the.

The control rod 6 is inserted from above through the flow path wall, and the control rod 6 has a screw 61 on the outer periphery of the intermediate portion.
It is screwed into a screw hole 31 formed at the upper end of the frame 33, extends further downward, and is fixed to the top surface of the valve body 2.

A guide rod 23 provided upright on the lower surface of the valve body 2.
Is provided with a disc-shaped valve plate 22 so as to be movable up and down, and the valve plate 22 is positioned at the lower end of the guide rod 23 while being biased downward by a coil spring 52. The valve plate 22 faces a bypass flow passage 43 that opens downward and connects the flow passage 41 and the flow passage 42.

The upper end of the control rod 6 is connected to a motor 7 by a known structure so as to be movable in the axial direction.
1 moves up and down by a predetermined amount. When the control rod 6 descends, the distance between the valve plate 21 and the valve seat 32 of the frame 33 that faces the valve plate 21 above the valve rod 21 increases, and the open area of the cooling water flow passage 42 increases, while the valve plate 22 and the bypass bypass. The distance between the opening of the flow path 43 and the opening edge is reduced, and the open area of the bypass flow path 43 is reduced. As a result, the amount of cooling water supplied to the radiator increases, heat dissipation of the cooling water is promoted, and the water temperature decreases. If the valve body 2 is raised when raising the water temperature, the flow rate of the bypass flow passage 43 increases, and the cooling water supply amount to the radiator decreases.

A temperature sensor 11 for detecting the cooling water temperature is provided on the flow path wall downstream of the valve body 2, and a signal from the temperature sensor 11 is input to the control circuit 1. The control circuit 1 has a built-in microcomputer and determines the operating state of the engine from the intake air temperature of the engine, the engine speed, the throttle opening, etc., and based on the detection signal of the alcohol concentration in the fuel, As described above, the rotation signal is output to the motor 7.

In FIG. 3, the alcohol concentration is read in step 101, and the target temperature of the engine cooling water stored in advance is set in step 102 according to the alcohol concentration. As shown in FIG. 4, this target temperature is increased as the concentration of alcohol having a large latent heat of vaporization in gasoline is increased to prevent an excessive decrease in the temperature of the engine combustion chamber wall.

In step 103, the operating state of the engine is determined based on the intake air temperature and the like, and the target temperature is corrected accordingly. Then, steps 105 and 10
At 6, the motor 7 is adjusted so that the cooling water temperature becomes the target temperature.
A rotation signal is outputted to the rotary actuator and the rotary signal is appropriately operated to change the position of the valve body 2. The above steps are repeated until the engine stops (step 107).

Thus, the cooling water supply amount to the radiator is changed in real time according to the alcohol concentration in the gasoline, and the cooling water temperature is changed so as to cancel the fluctuation of the latent heat of vaporization of the fuel, so that a good engine is always produced. The combustion state is maintained.

It is needless to say that the structure of the valve body for changing the amount of cooling water supplied to the radiator is not limited to that of the above-mentioned embodiment, and the water passage is replaced with the bypass passage and the valve body. The pump may be of a variable flow rate type and the cooling water supply amount to the radiator may be directly changed.

Further, instead of detecting the alcohol concentration or the like in real time, the kind of fuel whose mixing ratio is known is set in advance, and a predetermined amount of valve element is operated according to the set kind of fuel. It may be configured.

[0019]

As described above, according to the cooling water temperature control device of the present invention, it is possible to change the engine cooling water temperature in accordance with the thermal characteristics of the fuel used, and especially when the mixed fuel is used, it is always good. It is possible to maintain a good engine combustion state.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a complaint.

FIG. 2 is a configuration diagram of an apparatus including a cross-sectional view of a valve body installation portion.

FIG. 3 is a control flowchart of a control circuit.

FIG. 4 is a diagram showing a relationship between an alcohol concentration and a cooling water target temperature.

FIG. 5 is a cross-sectional view showing a conventional engine cooling water circulation path.

[Explanation of symbols]

 1 control circuit (target temperature setting means, control means) 2 valve body (cooling water supply amount changing means) 21, 22 valve plate 41, 42 cooling water flow passage 43 bypass flow passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Kobayashi 14 Iwatani Shimohakakucho, Nishio City, Aichi Prefecture Japan Auto Parts Research Institute, Inc.

Claims (1)

[Claims] 1. A means for setting a target temperature of engine cooling water according to the mixed concentration of fuel components of an engine, and changing an engine cooling water supply amount to a radiator according to an external signal. And a control means for outputting the external signal to the cooling water supply amount changing means in order to match the engine cooling water with the target temperature.