JPH0746729Y2 - Engine cooling water temperature control device for engine stop - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an engine cooling water temperature control device for an engine stop time, which is applied to a vehicle that performs water cooling pressure forced circulation type engine cooling with a radiator equipped with a condensation tank,
In particular, the present invention relates to an engine cooling water temperature control device for engine stop, which is effective in preventing a temperature rise of an injector that constitutes an electronically controlled fuel injection device.

2. Description of the Related Art A water-cooled pressure forced circulation type cooling device is generally adopted in recent automobile engines, and its radiator side will be described with reference to FIGS. 6 to 9. According to the drawing, a radiator 3 which is connected to an engine (not shown) and supplies engine cooling water is connected to a condensation tank 4 via a connecting pipe 9, and is attached to an engine cooling water injection nozzle 8 at the upper end of the radiator 4. By operating the pressure adjusting mechanism of the cap 7, the engine cooling water is cooled by the radiator 3
From the condensation tank 4 to the radiator 3 and vice versa, so that the internal pressure of the cooling device is kept higher than the atmospheric pressure to raise the boiling point of the engine cooling water. Therefore, the pressure adjusting mechanism provided on the cap 7 will be described in more detail. The pressure adjusting mechanism includes a pressurizing valve 12 and a pressure reducing valve 14, and normally both valves are closed by the force of the springs 13 and 18 as shown in FIG. Is about 0.9
The internal pressure of kg / cm ² is maintained. Therefore, the boiling point of the engine cooling water is increased by about 18 ° C, which is advantageous for the cooling device. However, when the internal pressure of the radiator 3 further rises above 0.9 kg / cm ² , as shown in FIG. 8, the pressurizing valve 12 is pushed up by the spring 13 contracted by the pressure, and the engine cooling water in the radiator 3 is connected to the connecting pipe. It flows through 9 to the condensation tank 4 which is open to the atmosphere. For this reason, the internal pressure of the radiator 3 drops, and when it falls to about 0.9 kg / cm ² , the pressurizing valve 1
2 closes and holds its pressure. Further, when the temperature of the engine cooling water decreases and the internal pressure of the radiator 3 also decreases, the negative pressure in the radiator causes the pressure reducing valve 14 to contract and open the spring 18, and the engine cooling water from the condensation tank 4 to the radiator 3. To maintain an appropriate internal pressure. In this way, in the water-cooled pressure forced circulation type cooling device, the internal pressure is raised to keep the boiling point high because it is advantageous for engine cooling.
Due to the high boiling point, the radiator itself and the circulation path of the engine cooling water also become hot. Moreover, when the engine is stopped after the vehicle stops running, the cold air is no longer forcibly supplied into the engine room, and the current situation is to wait until the high temperature radiator 3 and the like are naturally cooled.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, in recent years, an electronically controlled fuel injection device has been rapidly increasing as a fuel supply system to an engine, and its injector is attached to an intake manifold of the engine. For this reason, the injector is easily affected by the engine cooling water temperature, and as shown in FIG. 5, for example, between the engine cooling water shown by the solid line and the injector shown by the alternate long and short dash line, air does not flow in the engine room during traveling. Due to distribution, there is a temperature difference. However, if the engine is stopped after running harshly in the midsummer, heat will be retained because the air will not flow into the engine room, and the temperature of the engine cooling water will rise once and gradually rise above 110 ° C, then gradually. It will be naturally cooled. On the other hand, the injectors and other parts also start to rise in temperature under the influence of the engine cooling water temperature at the same time when the engine is stopped, and gradually approach the engine cooling water temperature with the passage of time. Therefore, if the engine is left for a short time and restarted after the engine is stopped, there is a disadvantage that the fuel injection by the injector cannot be controlled as desired, especially when the temperature of the injector is high. Further, the continued high temperature of 110 ° C. or higher was not preferable for other parts.

Means for Solving the Problems The present invention is to solve the above-mentioned problems, and in an engine cooling water temperature control device for an engine stop time of a vehicle that performs water cooling pressure forced circulation type engine cooling with a radiator equipped with a condensation tank, A water temperature sensor that measures the temperature of the engine cooling water, a timer that measures the time after the engine is stopped, and an electromagnetic on-off valve provided in the pressure reducing channel that branches from the engine cooling water circulation channel in the radiator and communicates with the condensation tank. When the engine cooling water is equal to or higher than a predetermined temperature even after a predetermined time elapses after the engine is stopped, the electromagnetic opening / closing valve is opened to reduce the pressure in the radiator. It is an engine cooling water temperature control device for engine stop.

Action According to the above-mentioned means, when the engine cooling water has a temperature equal to or higher than the predetermined temperature when the predetermined time has elapsed after the engine is stopped, the depressurizing flow path is branched from the engine cooling water circulation path in the radiator and communicates with the condensation tank. By opening the provided electromagnetic on-off valve, the engine cooling water, which has a high temperature and high pressure in the radiator, flows into the condensation tank through the pressure reducing passage. For this reason, the pressure in the radiator is lowered, the boiling point of the engine cooling water is lowered, and the engine cooling water consumes a large amount of heat of vaporization and boils, so that the temperature is drastically lowered.

Embodiment An embodiment of the engine cooling water temperature control device for engine stop according to the present invention will be described with reference to FIGS. 1 to 5. The engine cooling water temperature control device for engine stop measures the temperature of engine cooling water. A water temperature sensor 1, a timer 2 for measuring the time after the engine is stopped, and an electromagnetic on-off valve 6 provided in a pressure reducing passage 5 branching from the engine cooling water circulation passage in the radiator 3 and communicating with the condensation tank 4. The temperature of the engine cooling water is measured by the water temperature sensor 1 at the same time as the timer 2 measures the elapse of a predetermined time after the engine is stopped (not shown). In some cases, the solenoid on-off valve 6 is opened to reduce the pressure in the radiator. Reference numeral 7 is a cap provided with a pressure adjusting mechanism, 8 is an engine cooling water injection nozzle, 9 is a connecting pipe, 10 is an overflow pipe, and 11 is a battery power source.

According to the engine cooling water temperature control device for engine stop having the above-described configuration, the electromagnetic opening / closing valve 6 is normally closed as shown in FIG. 2, the pressure adjusting mechanism of the cap 7 is operated, and the internal pressure of the radiator 3 is 0.9 kg. / cm ² is kept. And
When the engine is stopped by running harshly in midsummer, the temperature of the engine cooling water will be about 120 ° C as shown in Fig. 5.
After the temperature rises to ℃, it gradually cools down and begins to fall. Therefore, the engine cooling water temperature is measured by the water temperature sensor 1, and at the same time, the time after the engine is stopped is measured by the timer 2. For example, when the engine cooling water temperature is 100 ° C. or higher 10 minutes after the engine is stopped, the electromagnetic opening / closing valve 6 open. Then, the high-temperature and high-pressure engine cooling water flows from the radiator 3 through the depressurization flow path 5 into the condensation tank 4 which is open to the atmosphere, as shown by the arrow in FIG. As a result, the internal pressure of the radiator 3 is lowered and the boiling point of the engine cooling water is lowered, so that the engine cooling water consumes large heat of vaporization and boils. For this reason, the temperature of the engine cooling water drops sharply 10 minutes after the engine is stopped, as shown by the broken line in FIG. Therefore, the temperature of the injector for the electronically controlled fuel injection device, which is mounted on the intake manifold and is affected by the engine cooling water temperature, is 10 minutes after the engine is stopped, as shown by the chain double-dashed line in FIG. Since the temperature difference between and is small, the rising gradient is also small, and the engine cooling water temperature is asymptotically lower than in the past, so the temperature rise of the injector can be suppressed low. The reason why the electromagnetic on-off valve 6 is not opened immediately after the engine is stopped is because the boiling amount of the engine cooling water is too large, and moreover, since the temperature rise of the injector is slow, even after about 10 minutes have elapsed. There is no big difference in the effect.

Further, FIGS. 3 and 4 show second and third embodiments utilizing the pressure adjusting mechanism of the cap 7. Second of FIG. 3
In the embodiment, an electromagnet 19 is provided on the pressurizing valve 12 of the cap 7 ', and when the engine cooling water is at a predetermined temperature or higher after a predetermined time elapses after the engine is stopped, the electromagnet 19 is energized to pressurize the valve 12. Is configured to pull up. When the pressurizing valve 12 is pulled up, the high-temperature and high-pressure engine cooling water in the radiator 3 flows into the condensation tank 4 through the connecting pipe 9, and the radiator internal pressure lowers and the boiling point also lowers. The pressurizing valve 12 normally maintains the internal pressure of the radiator 3 at about 0.9 kg / cm ² by the action of the spring 13. Next, referring to the third embodiment of FIG. 4, a pressure chamber 15 integrated with the pressure reducing valve 14 of the cap 7 ″ is provided, and a spring is provided therein.
Set 16 Further, a communication pipe 17 is provided in the pressure chamber 15 via the timer 2'and the check valve 16 so that the negative pressure of the intake manifold acts, and the negative pressure acting on the pressure chamber 15 when the engine is stopped causes the negative pressure to act as an orifice. The spring 16 is constructed so as to overcome the internal pressure of the radiator 3 and open at the time when it slowly disappears from the timer 2 '. When the pressure reducing valve 14 is opened, the high-temperature and high-pressure engine cooling water flows from the pressure reducing valve 14 through the connecting pipe 9 into the condensation tank 4 as indicated by the arrow, and the internal pressure of the radiator is lowered and the boiling point is also lowered. Although the pressure reducing valve 14 is closed under the negative pressure of the intake manifold during normal traveling, it naturally opens when the temperature of the engine cooling water drops and a negative pressure is generated in the radiator. 3 has the effect of maintaining an appropriate internal pressure. The fifth
The changes in the engine water temperature and the temperature of the injector shown in the figure facilitate the explanation, and it goes without saying that they change depending on the temperature and other conditions.

Effect of the Invention According to the above-described present invention, the engine cooling water temperature rise after the engine is stopped can be suppressed to a low level even under severe conditions such as driving harshly in the midsummer. Therefore, the temperature rise of the injectors and other parts around the engine that are affected by the engine cooling water temperature is also reduced, and it is possible to prevent the injectors from becoming so hot as to adversely affect the fuel injection control at the time of restart.

[Brief description of drawings]

1 and 2 are system diagrams showing an embodiment of an engine cooling water temperature control device for engine stop according to the present invention.
The figure shows a state in which the solenoid on-off valve is opened, FIG. 2 shows the state in which the solenoid on-off valve is closed, FIG. 3 shows the second embodiment of the present invention, and FIG. 4 shows the present invention. FIG. 5 is a diagram showing a third embodiment, FIG. 5 is a diagram showing changes in temperature of engine cooling water and an injector after the engine is stopped, and FIG. 6 is a system diagram showing a conventional example,
7 to 9 are enlarged views of the portion VII of FIG. 6 showing the pressure adjusting mechanism of the cap, and FIG. 7 is a view showing a normal state in which both the pressurizing valve and the pressure reducing valve are closed, FIG. 8 is a diagram showing a state in which the inside of the radiator has become high temperature and high pressure and the pressurizing valve is opened, and FIG. 9 is a diagram showing a state in which the pressure inside the radiator is lowered and the pressure reducing valve is opened. 1 ... Water temperature sensor, 2, 2 '... Timer, 3 ... Radiator, 4 ... Condensation tank, 5 ... Decompression flow path, 6 ...
Electromagnetic on-off valve, 7,7 ', 7 "... Cap, 8 ... Engine cooling water injection nozzle, 9 ... Connection pipe, 10 ... Overflow pipe, 11 ... Battery power supply, 12 ... Pressure valve,
13,18 ... Spring, 14 ... Reducing valve, 15 ... Pressure chamber, 16 ...
Check valve, 17 ... Communication pipe.

Claims (1)

[Scope of utility model registration request] Claims: 1. An engine cooling water temperature control device for stopping an engine of a vehicle in which a radiator equipped with a condensation tank is used to perform water cooling pressure forced circulation type engine cooling; a water temperature sensor for measuring the temperature of the engine cooling water; A timer for measuring the time, and an electromagnetic on-off valve provided in the pressure reducing flow path that branches from the engine cooling water circulation flow path in the radiator and communicates with the condensation tank, and a predetermined time elapses after the engine is stopped. Also, when the engine cooling water is at a predetermined temperature or higher, the electromagnetic on-off valve is opened to reduce the pressure inside the radiator, and the engine cooling water temperature control device for engine stop is characterized.