JPH0746731Y2 - Engine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an engine cooling device.

(Prior Art) Conventionally, in a heater device of an automobile using engine cooling water, a cock is provided in a heater inlet passage for introducing cooling water into the heater, and the cock is opened when the heater is used and closed when not used. As a result, the cooling water was circulated through the heater only when the heater was used, but due to the complexity of the cock switching work, no cock has been provided recently,
Regardless of whether or not a heater is used, cooling water is circulated on the emergency heater side, and heating / non-heating is switched by opening / closing a damper on the passenger compartment side, which is becoming the mainstream (for example, Japanese Patent Laid-Open No. 62-199920). See the bulletin).

FIG. 2 shows a cooling system for an automobile engine equipped with such a constant water flow type heater device. This cooling system will be briefly described below. The cooling water outlet 1a of the engine 1
The cooling water inlet 2a of the radiator 2 and the cooling water outlet passage 3
The cooling water inlet 1b of the engine 1 and the cooling water outlet 2b of the radiator 2 are connected by a cooling water inlet passage 4, and a thermostat 5 and a water pump 11 are provided in the cooling water inlet passage 4. Further, a bypass passage 6 connects the cooling water outlet passage 3 and the thermostat 5.

Then, while introducing cooling water into the heater 7 from the cooling water outlet 1a of the engine 1 through the heater inlet passage 8,
The cooling water after passing through the heater 7 is returned to the downstream side of the thermostat 5 in the cooling water inlet passage 4 through the heater outlet passage 9.

In this cooling system, the temperature of the cooling water is the thermostat 5.
When the temperature is equal to or higher than the temperature set by, the thermostat 5 opens the cooling water inlet passage 4 and closes the bypass passage 6. The cooling water after cooling the engine 1 circulates through the radiator 2 and radiates heat there to become low-temperature cooling water, and then is returned to the engine 1 side again. On the other hand, when the cooling water temperature is equal to or lower than the set temperature, the cooling water inlet passage 4 is closed and the bypass passage 6 is opened.
Therefore, the cooling water is returned to the engine 1 side as it is from the bypass passage 6 without passing through the radiator 2, and thus the supercooling of the engine 1 is prevented.

Although the cooling water circulates in the heater 7 at all times during engine operation, the damper on the passenger compartment side is closed in the summer and the damper is opened to blow air in the winter to heat the passenger compartment only in the winter. Is possible.

(Problems to be Solved by the Invention) As described above, in the conventional cooling system, the thermostat 5 is controlled only by the temperature of the cooling water after the engine is cooled, so that the engine temperature is stable at the set temperature of the thermostat 5. become. Then, normally, the set temperature of the thermostat 5 is set to about 82 ° C, and the temperature of the cooling water after engine cooling rises to about 88 ° C.

On the other hand, it is said that the temperature of the cooling water at the heater inlet needs to be maintained at around 90 ° C. in order to obtain sufficient heater performance.

However, in the above conventional cooling system, since the return cooling water from the heater 7 is simply returned to the downstream side of the thermostat 5, in the winter when the heater 7 is used, the low temperature cooling radiated by the heater 7 is performed. Water is returned to the downstream side of the thermostat 5. Therefore, the water temperature on the cooling water inlet 51b side of the engine 1 does not rise above the set temperature of the thermostat 5 and the engine temperature stabilizes at a temperature below the set temperature of the thermostat 5, and as a result, the heater inlet There was a problem that the cooling water temperature could not be obtained sufficiently and the heating performance deteriorated.

As one method of solving such a problem, it is conceivable to raise the set temperature itself of the thermostat 5. In such a case, it is good because sufficient heating performance can be obtained in the winter, but in the summer On the contrary, since the cooling water temperature is not lowered, the engine temperature is stabilized at the high set temperature of the thermostat 5, which may adversely affect the reliability of the engine 1, which is not preferable.

Further, the present invention has been made for the purpose of providing an engine cooling device capable of improving heating performance without impairing the reliability of the engine.

(Means for Solving the Problem) In the present invention, as a concrete means for solving such a problem, the cooling water outlet of the engine and the cooling water inlet of the radiator are provided in a cooling water outlet passage, and the cooling water inlet of the engine and the radiator are provided. The cooling water outlet is connected with a cooling water inlet passage equipped with a thermostat that opens and closes in accordance with the cooling water temperature, and the cooling water outlet and the thermostat are connected with a bypass passage bypassing the radiator to cool the cooling water temperature. When the temperature is equal to or higher than the set value, the thermostat is opened to flow the cooling water to the radiator, and when the temperature is lower than the set value, the thermostat is closed and the cooling water is returned to the engine side without passing through the radiator, Further, the cooling water outlet of the engine and the cooling water inlet of the heater are connected by a heater inlet passage, and In the engine cooling device, the cooling water outlet of the engine is connected to the thermostat downstream position of the cooling water inlet passage through the heater outlet passage, and the cooling water is continuously circulated to the heater during engine operation. A branch passage branched from the heater outlet passage is connected to the thermostat.

(Operation) Since the present invention has such a configuration, (1) In the summer, even if a part of the cooling water refluxed from the heater hits the thermostat, the temperature of the heater itself does not perform a heat exchange operation. Is almost the same as the temperature of the cooling water returned from the engine side, and the engine temperature is stable at the set temperature of the thermostat. (2) In winter, the cooling water returned from the heater by using the heater The temperature is low, and when the low-temperature cooling water hits the thermostat, the thermostat operates at a temperature lower than the actual engine temperature and its set temperature is substantially increased. Despite the return to the downstream side, the temperature of the cooling water at the engine outlet, that is, the cooling water at the heater inlet, Water temperature is maintained at about the same as the summer, effects etc. are obtained.

(Effects of the Invention) Therefore, according to the engine cooling device of the present invention, since a part of the return cooling water from the heater is applied to the thermostat, the return cooling is performed in the summer when there is no heat radiation by the heater. The engine temperature is stabilized by the set temperature of the thermostat without being affected by the introduction of water into the thermostat, thereby preventing overheating of the engine and ensuring its reliability. In the winter when the temperature of the thermostat decreases, a part of the side return cooling water is introduced into the thermostat, so that the set temperature of the thermostat is substantially increased and the temperature of the cooling water at the heater inlet is maintained at a high temperature. Maintaining the reliability of the engine and maintaining the heating performance of the heater, such as maintaining the standard heating performance It is possible to obtain the practical effect that both are compatible.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a cooling device for an automobile engine according to an embodiment of the present invention. This cooling device has the same basic configuration as that of the above-described conventional example. The difference from the conventional example is that the present invention is applied to branch the branch passage 10 from the heater outlet passage 9. This is the point where one end of the branch passage 10 is connected to the thermostat 5. Therefore, here, only the operation and effect of providing the branch passage 10 will be described in detail, and other configurations will be omitted by giving the reference numerals corresponding to the respective members of FIG.

When the branch passage 10 is provided, a part of the return cooling water from the heater 7 is directly introduced into the thermostat 5 during the operation of the engine 1. In this case, the return cooling water from the heater 7 is used when the heater is not used (that is, in the summer).
In the above, since there is no heat dissipation effect in the heater 7, it is considered as high temperature cooling water having substantially the same temperature as the return cooling water from the engine 1, but when the heater is used (that is, in the winter) The low-temperature cooling water is considerably lower than the return cooling water from the engine 1.

Therefore, when the heater is not used, even if the return cooling water from the heater 7 is introduced into the thermostat 5, the operation of the thermostat 5 is controlled only by the temperature of the high temperature cooling water returned from the engine 1. Since the engine temperatures are substantially the same, the engine temperature stabilizes at the set temperature of the thermostat 5, and the overheating of the engine 1 is reliably prevented and its reliability is secured.

On the other hand, when the heater is used, the thermostat 5 uses the mixed cooling water of the high temperature cooling water from the engine 1 and the low temperature cooling water from the heater 7 (the water temperature is lower than that of the high temperature cooling water from the engine 1). The operation is controlled.
Therefore, the thermostat 5 is controlled by the cooling water temperature lower than the water temperature corresponding to the actual engine temperature (in other words, the set temperature of the thermostat 5 is substantially increased). Therefore, if the low-temperature cooling water is not introduced into the thermostat 5, the engine inlet water temperature that rises below the set temperature of the thermostat 5 by the low-temperature cooling water from the heater 7 that is returned to the downstream side of the thermostat 5 is set. It is possible to raise the temperature to the temperature or higher, and as a result, the temperature of the cooling water at the inlet of the heater 7 is maintained at the same high temperature as when the heater is not used, and the heating performance of the heater 7 is improved.

As described above, in the engine cooling device of this embodiment, the reliability of the engine 1 and the heating performance of the heater 7 are improved by the extremely simple means of providing the branch passage 10 to the conventional cooling structure. It can be realized at the same time.

The heater outlet passage 9 is directly connected to the thermostat 5 instead of the structure in which the heater outlet passage 9 is branched and the branched passage 10 is connected to the thermostat 5 as in this embodiment.
It is not unthinkable to connect all of the return cooling water from the heater 7 to the thermostat 5 by connecting it to the thermostat 5. However, in such a case, at the time of extremely low temperature (for example, -30 ° C or less), the thermostat Since the valve opening operation of No. 5 is delayed too much and the engine temperature rises excessively, the reliability of the engine 1 may be adversely affected, which is not preferable.

[Brief description of drawings]

FIG. 1 is an overall system diagram of an engine cooling device according to an embodiment of the present invention, and FIG. 2 is a system diagram of a conventional engine cooling device. 1 ... Engine 2 ... Radiator 3 ... Cooling water outlet passage 4 ... Cooling water inlet passage 5 ... Thermostat 6 ... Bypass passage 7 ... Heater 8 ... Heater inlet passage 9 ... Heater outlet passage 10 ... Branch passage 11 …… Water pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References: 61-147326 (JP, U): 61-178024 (JP, U): 59-184318 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A cooling system having a thermostat for opening and closing a cooling water outlet of an engine and a cooling water inlet of a radiator in a cooling water outlet passage, and opening and closing a cooling water inlet of an engine and a cooling water outlet of a radiator in accordance with a cooling water temperature. While connecting each with a water inlet passage, the cooling water outlet and the thermostat are connected by a bypass passage that bypasses the radiator, and when the cooling water temperature is equal to or higher than a set value, the thermostat is opened to allow the cooling water to flow to the radiator. When the temperature is below the set value, the thermostat is closed to allow the cooling water to recirculate to the engine side without passing through the radiator, and the cooling water outlet of the engine and the cooling water inlet of the heater are connected in the heater inlet passage. The cooling water outlet of the heater is connected to the thermostat of the cooling water inlet passage through the heater outlet passage. A cooling device for an engine, which is connected to a downstream position to allow cooling water to continuously flow through the heater during engine operation, wherein a branch passage branched from the heater outlet passage is connected to the thermostat. Characteristic engine cooling system.