JP3906745B2 - Cooling device for internal combustion engine - Google Patents

Description

[0001]
The present invention relates to a cooling device for an internal combustion engine, and more particularly to a cooling device for an internal combustion engine that can be warmed up early in a water-cooled cooling device.
[0002]
[Prior art]
In an internal combustion engine for a vehicle, early warm-up at the start of the engine is very important for improving fuel efficiency and exhaust emission. As for early warm-up of a water-cooled internal combustion engine, a warm-up method using a heat storage tank has been proposed as described in, for example, JP-A-2001-140644. The internal combustion engine disclosed in this publication stores heat by storing high-temperature cooling water flowing through the cooling water circuit in the heat storage tank during engine operation, and stores the high-temperature cooling water stored in the heat storage tank. By supplying the internal combustion engine via the cooling water circuit at the next engine start, the internal combustion engine is warmed up early.
[0003]
Further, the internal combustion engine described in the above publication also performs heating of the passenger compartment using cooling water. That is, the heater core provided in the cooling water circuit collects heat from the high-temperature cooling water flowing out from the internal combustion engine, and uses this heat to blow warm air into the vehicle interior.
[0004]
[Problems to be solved by the invention]
However, the conventional cooling device for an internal combustion engine has a relatively low temperature cooling in the heater core if the cooling water is circulated through the heating of the passenger compartment, that is, the heater core immediately after the start of the operation of the internal combustion engine after the warm-up. Water is returned to the internal combustion engine, and the temperature of the cooling water warmed by warm-up is rapidly reduced.
[0005]
For example, when the temperature of the internal combustion engine is estimated based on the temperature of the cooling water and the fuel injection amount is controlled so that the air-fuel ratio becomes a predetermined value, the temperature of the cooling water suddenly decreases. Due to the decrease, the fuel injection amount control is adversely affected, and as a result, problems such as disturbance of the air-fuel ratio occur.
[0006]
The present invention has been made in view of such problems, and an object of the present invention is to provide a cooling device for an internal combustion engine that prevents a rapid temperature drop of cooling water flowing through the internal combustion engine. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a cooling apparatus for an internal combustion engine according to the present invention includes a water-cooled internal combustion engine, a heat storage tank for storing high-temperature cooling water heated by the internal combustion engine, and collects heat from the cooling water. And collecting the cooling water into the cooling water for warming circulating between the internal combustion engine and the heat storage tank, and the cooling water for collecting heat circulating between the internal combustion engine and the heat collecting means And controlling the flow rate adjusting valve for adjusting the flow rates of the warming-up cooling water and the heat collecting cooling water, and controlling the flow rate adjusting valve so that the high-temperature cooling water stored in the heat storage tank is supplied to the internal combustion engine. And the warm-up control means controls the flow rate adjusting valve when the cooling water in the heat collection means is equal to or lower than a predetermined temperature, and the heat collection control means by adjusting the flow rate of the use coolant to a predetermined small flow rate, the heat collecting hand It shall be raised to a predetermined temperature of cooling water of the inner gradually warm.
[0008]
According to the above configuration, a large amount of low-temperature cooling water in the heat collecting means flows into the internal combustion engine, and the temperature of the cooling water flowing through the internal combustion engine is prevented from rapidly decreasing, and in the heat collecting means The low-temperature cooling water can be gradually warmed. Thereby, for example, in an apparatus that performs fuel injection control or the like based on the temperature of cooling water flowing in the internal combustion engine, it is possible to suppress disturbances such as injection amount control due to a rapid decrease in water temperature.
[0009]
Preferably, the predetermined temperature is a temperature of the warm-up cooling water.
[0010]
Preferably, the predetermined minute flow rate is a flow rate that does not substantially lower the temperature of the cooling water after joining the cooling water for collecting heat and the cooling water for warming up from the temperature of the cooling water for warming up before joining. And
[0011]
Desirably, it further has a water temperature sensor for detecting the temperature of the cooling water in the heat collecting means, and the warm-up control means measures the temperature of the cooling water in the heat collecting means based on the detection result of the water temperature sensor. It shall be.
[0012]
Preferably, the warm-up control means determines the temperature of the cooling water in the heat collecting means based on experimental results obtained in advance according to the flow rate and circulation time of the heat collecting cooling water.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Preferred embodiments of the invention will be described below with reference to the drawings.
[0014]
FIG. 1 is a configuration diagram showing the overall configuration of a cooling device for a water-cooled engine mounted on a vehicle. The engine 10 which is an internal combustion engine has a cooling water passage 12 therein, and the cooling water flows through the cooling water passage 12 to cool the engine 10. An engine pump 14 driven by a crankshaft (not shown) of the engine 10 is connected to the upstream side of the cooling water passage 12, and the cooling water is pumped to the cooling water passage 12 by the engine pump 14. Is done.
[0015]
A cooling water passage 16 is connected to the downstream side of the cooling water passage 12 of the engine 10 so that the cooling water flows to the suction side of the engine pump 14 via the thermostat valve 18 and the cooling water passage 20. ing. The thermostat valve 18 is connected to the water inlet of the radiator 24 via the cooling water passage 22, and the water outlet of the radiator 24 is connected to the suction side of the engine pump 14 via the cooling water passage 26. The cooling water passage 20 and the cooling water passage 26 are connected to the suction side of the engine pump 14 after joining.
[0016]
The thermostat valve 18 is a valve that switches the flow path of the cooling water according to the temperature of the cooling water. When the temperature of the cooling water flowing through the thermostat valve 18 is higher than the predetermined temperature Ts, the thermostat valve 18 is closed. The cooling water passage 16 and the cooling water passage 22 are connected, and when the cooling water temperature is equal to or lower than the predetermined temperature Ts, the cooling water passage 22 side is closed and the cooling water passage 16 and the cooling water passage 20 are connected.
[0017]
Accordingly, when the coolant temperature is higher than the predetermined temperature Ts during operation of the engine 10, the coolant is supplied from the engine pump 14 → the engine coolant passage 12 → the coolant passage 16 → the thermostat valve 18 → the coolant passage 22 → The cooling water that circulates in the closed circuit of the radiator 24 → the cooling water passage 26 → the engine pump 14 and is heated in the engine 10 is cooled when passing through the radiator 24.
[0018]
On the other hand, when the cooling water temperature is equal to or lower than the predetermined temperature Ts during operation of the engine 10, the cooling water is supplied from the engine pump 14 → the engine cooling water passage 12 → the cooling water passage 16 → the thermostat valve 18 → the cooling water passage 20 → the engine. Circulates in the closed circuit of the pump 14 for use.
[0019]
The cooling water passage 12 of the engine 10 is also connected to a circuit different from the circuit described above. That is, the downstream side of the cooling water passage 12 is a cooling water passage 28, a three-way switching valve 30 that is a flow rate adjusting valve, a cooling water passage 32, a water temperature sensor 34, a heat storage tank 36, a heat storage tank pump 38, a cooling water passage 40, The engine pump 14 is connected via a cooling water passage 26. Accordingly, the engine pump 14 → the engine coolant passage 12 → the coolant passage 28 → the three-way switching valve 30 → the coolant passage 32 → the heat storage tank 36 → the heat storage tank pump 38 → the coolant passage 40 → the coolant passage 26 → A closed circuit is formed in which the warm-up coolant circulating with the engine pump 14 flows.
[0020]
This closed circuit warms up the engine 10 with high-temperature cooling water stored in the heat storage tank 36 when the high-temperature cooling water heated by the engine 10 is introduced and stored in the heat storage tank 36 or when the engine 10 is started. It is a circuit used when The heat storage tank pump 38 is a pump driven by an electric motor (not shown), and therefore can be operated even before the engine 10 is cranked. On the other hand, the engine pump 14 is a pump driven by the crankshaft of the engine 10 as described above, and therefore cannot be operated before cranking. The three-way switching valve 30 is also connected to a cooling water passage 42, and a heater core 44 for heating the vehicle interior is connected to the cooling water passage 42 via a heater pump 46. That is, the heater core 44 functions as a heat collecting means for collecting heat from the cooling water heated by the engine 10.
[0021]
As a result, the engine pump 14 circulates between the engine coolant passage 12, the coolant passage 28, the three-way switching valve 30, the coolant passage 42, the heater core 44, the coolant passage 40, the coolant passage 26, and the engine pump 14. A closed circuit through which the cooling water for heat collection flows is formed. The heater core 44 is provided with a water temperature sensor 52.
[0022]
The three-way switching valve 30 is a valve that selectively connects the cooling water passage 28 to one of the cooling water passage 32 and the cooling water passage 42, and the warm-up control means 50 in the ECU 48 controls the operation of the three-way switching valve 30. Control and switch the cooling water flow path.
[0023]
When a mode selection switch (not shown) of the air conditioner is set to the “heating mode”, the warm-up control means 50 controls the three-way switching valve 30 to connect the cooling water passage 28 and the cooling water passage 42, and further the heater The pump 46 is driven. As a result, in addition to the cooling water flow described above, a part of the cooling water flowing out from the engine cooling water passage 12 is cooled by the cooling water passage 28 → the three-way switching valve 30 → the cooling water passage 42 → the heater pump 46 → the heater core. 44 → cooling water passage 40 flows and joins the cooling water passage 26, and the heater core 44 takes heat from the high-temperature cooling water heated by the engine and uses this heat for warm air in the passenger compartment.
[0024]
Next, a case where hot cooling water is stored in the heat storage tank 36 to store heat and an operation of warming up the engine 10 with the high temperature cooling water stored in the heat storage tank 36 when the engine 10 is started will be described.
[0025]
In this embodiment, heat storage is performed immediately after the engine 10 is stopped. That is, the warm-up control means 50 controls the three-way switching valve 30 so as to connect the cooling water passage 28 and the cooling water passage 32 in accordance with an engine stop signal (for example, an ignition switch OFF signal), and also for heat storage. The pump 38 is operated. Thereby, the cooling water is the engine cooling water passage 12 → the cooling water passage 28 → the three-way switching valve 30 → the cooling water passage 32 → the water temperature sensor 34 → the heat storage tank 36 → the heat storage tank pump 38 → the cooling water passage 40 → the cooling water. The closed circuit returns to the cooling water passage 12 via the passage 26 → the engine pump 14. However, in this case, since the engine 10 is stopped, the engine pump 14 is not operated. That is, the cooling water flowing in the engine cooling water passage 12 is flowed by the heat storage pump 38.
[0026]
Next, warm-up at the time of starting will be described. When the engine 10 is started, the warm-up control means 50 controls the three-way switching valve 30 so as to connect the cooling water passage 28 and the cooling water passage 32 before starting operation of the engine, that is, before cranking. The pump 38 is driven. Thereby, the cooling water is stored in the heat storage tank 36 → the cooling water passage 40 → the cooling water passage 26 → the engine pump 14 → the engine cooling water passage 12 → the cooling water passage 28 → the three-way switching valve 30 → the cooling water passage 32 → the water temperature sensor. It flows through the closed circuit which returns to the thermal storage tank 36 through 34. Moreover, since the engine 10 is before cranking, the engine pump 14 is not operated. Therefore, the cooling water flowing in the engine cooling water passage 12 is flowed by the heat storage tank pump 38. During the warm-up, it is desirable that the cooling water does not circulate to the heater core 44. That is, warming up is performed efficiently by avoiding a decrease in cooling water temperature due to heat collection of the heater core 44.
[0027]
As described above, it is desirable that the warm-up is performed before the engine 10 is started, and the engine 10 is started after the engine 10 reaches a desired temperature due to the warm-up. However, even if the warm-up is sufficiently performed, the cooling water present inside the heater core 44 remains at a low temperature. That is, the temperature of the cooling water in the heater core 44 remains low even though the engine 10 reaches a desired temperature and the temperature of the warming-up cooling water circulating between the engine 10 and the heat storage tank 36 is high. It is. If the cooling water in the heater core 44 is injected into the warm-up cooling water in this state, the temperature of the injected cooling water, that is, the cooling water flowing into the engine 10 is drastically lowered, and the engine cooling water The engine controls based on the temperature of the engine may be adversely affected.
[0028]
In order to avoid this, the warm-up control means 50 controls the three-way switching valve 30 to gradually increase the temperature of the cooling water in the heater core 44 and then fully open the circulation of the cooling water to the heater core 44. Good.
[0029]
FIG. 2 is a flowchart showing the control of the three-way switching valve 30 by the warm-up control means 50. In the following description of FIG. 2, the same elements as those shown in FIG.
[0030]
When a start instruction for the engine 10, for example, an engine start key is input by a driver, in step 1, the engine 10 is warmed up. After the warm-up is sufficiently executed in Step 1, the engine 10 is started in Step 2.
[0031]
After the engine 10 is started, in step 3, the three-way switching valve 30 is controlled so that the flow rate of the cooling water for collecting heat circulating between the engine 10 and the heater core 44 is smaller than a predetermined flow rate. As the predetermined flow rate, when the low-temperature cooling water inside the heater core 44 merges with the high-temperature warm-up cooling water circulating between the engine 10 and the heat storage tank 36, the temperature of the cooling water returning to the engine 10 after merging decreases. It is set as a theoretical calculated value that does not adversely affect the control of the engine 10, or as a value obtained through experiments.
[0032]
Next, in step 4, the coolant temperature in the heater core 44 is compared with the coolant temperature of the warm-up coolant. When both are substantially equal, it is determined that the temperature of the cooling water in the heater core 44 has risen to a predetermined temperature, the restriction on the flow rate of the cooling water for heat collection is released, and the cooling for heat collection is performed as necessary for heating the vehicle interior. Fully open the water. When both are not substantially equal, it is determined that the temperature of the cooling water in the heater core 44 has not risen to the predetermined temperature, and the process returns to step 3 to keep the flow rate of the cooling water for collecting heat smaller than the predetermined flow rate. To do.
[0033]
The temperature of the cooling water in the heater core 44 may be calculated theoretically based on the measured value obtained from the water temperature sensor 52 for the heater core, the flow rate of the cooling water for heat collection or the circulation time, or An experiment according to the flow rate of the cooling water for collecting heat and the circulation time may be performed, and an estimated value from the experiment result may be used.
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a cooling device for an internal combustion engine that prevents a rapid temperature drop of cooling water flowing through the internal combustion engine.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a cooling device for an internal combustion engine according to the present invention.
FIG. 2 is a flowchart showing a control procedure of warm-up control means.
[Explanation of symbols]
10 engine, 30 three-way switching valve, 34 water temperature sensor, 36 heat storage tank, 38 heat storage tank pump, 50 warm-up control means, 52 water temperature sensor.

Claims (5)

A water-cooled internal combustion engine;
A heat storage tank for storing high-temperature cooling water heated by the internal combustion engine;
A heat collecting means for collecting heat from the cooling water;
The coolant is divided into warm-up coolant that circulates between the internal combustion engine and the heat storage tank, and heat-collection coolant that circulates between the internal-combustion engine and the heat collecting means, and the warm-up A flow rate adjustment valve for adjusting the flow rate of the cooling water for cooling and the cooling water for heat collection;
A warm-up control means for controlling the flow rate adjusting valve and supplying the internal combustion engine with hot cooling water stored in the heat storage tank to warm up;
Have
The warm-up control means controls the flow rate adjusting valve when the cooling water in the heat collecting means is below a predetermined temperature, and adjusts the flow rate of the cooling water for heat collection to a predetermined minute flow rate, thereby collecting heat Gradually warm the cooling water in the means to a predetermined temperature,
A cooling device for an internal combustion engine , characterized in that: A cooling device for an internal combustion engine according to claim 1,
The cooling apparatus for an internal combustion engine, wherein the predetermined temperature is a temperature of the warm-up cooling water. A cooling device for an internal combustion engine according to claim 1 or 2,
The predetermined minute flow rate is a flow rate that does not substantially lower the temperature of the cooling water after joining the cooling water for heat collection and the cooling water for warm-up from the temperature of the cooling water for warm-up before joining. Cooling device for internal combustion engine. A cooling device for an internal combustion engine according to any one of claims 1 to 3,
A water temperature sensor for detecting the temperature of the cooling water in the heat collecting means;
The cooling device for an internal combustion engine, wherein the warm-up control means measures a coolant temperature in the heat collecting means based on a detection result of the water temperature sensor. A cooling device for an internal combustion engine according to any one of claims 1 to 3,
The cooling apparatus for an internal combustion engine, wherein the warm-up control means determines the water temperature of the cooling water in the heat collecting means based on experimental results obtained in advance according to the flow rate and circulation time of the heat collecting cooling water.

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