JP2004011623A - Cooling device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device for an internal combustion engine which prevents a sudden temperature fall of cooling water circulating in the internal combustion engine. <P>SOLUTION: A warming-up control means 50 controls a pump 38 for a heat accumulation tank and a three-way selector valve 30 and warms up the engine by supplying the hot cooling water pooled in the heat accumulation tank 36 to the engine 10. When temperature of the cooling water returned from a heater core 44 to the engine 10 is below that of the cooling water discharged from the heat accumulation tank 36, the warming-up control means 50 controls the three-way selector valve 30 and adjusts a flow rate of the cooling water circulating through the heater core 44 and the engine 10 below a predetermined flow rate. <P>COPYRIGHT: (C)2004,JPO

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 quickly warmed up in a water-cooled cooling device.
[0002]
[Prior art]
In an internal combustion engine for a vehicle, early warm-up at the time of engine start is very important for improving fuel efficiency and exhaust emission. Regarding the early warm-up of a water-cooled internal combustion engine, a warm-up method using a heat storage tank has been proposed, for example, as described in JP-A-2001-140644. The internal combustion engine disclosed in this publication stores heat by storing high-temperature cooling water flowing through a cooling water circuit in a heat storage tank during engine operation, and stores the high-temperature cooling water stored in the heat storage tank. When the engine is started next time, the internal combustion engine is supplied to the internal combustion engine via the cooling water circuit, so that the internal combustion engine is quickly warmed up.
[0003]
Further, the internal combustion engine described in the above-mentioned publication also heats a vehicle interior using cooling water. That is, the heater core provided in the cooling water circuit collects heat from the high-temperature cooling water discharged from the internal combustion engine, and uses the 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 heats the vehicle interior, that is, circulates cooling water to the heater core immediately after the internal combustion engine starts operating after the warming-up. The water is returned to the internal combustion engine, and the temperature of the cooling water heated by the warm-up is rapidly reduced.
[0005]
The sudden decrease in the temperature of the cooling water is, for example, when the warm-up 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. Due to the decrease, the fuel injection amount control is adversely affected, and as a result, problems such as a disturbance in the air-fuel ratio occur.
[0006]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a cooling device for an internal combustion engine that prevents a rapid decrease in temperature of cooling water flowing through the internal combustion engine. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a cooling device 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 collecting heat from the cooling water. Heat collecting means, cooling water circulating between the internal combustion engine and the heat storage tank, and cooling water circulating between the internal combustion engine and the heat collecting means. And a flow control valve for controlling the flow rates of the warm-up cooling water and the heat collection cooling water, and controlling the flow control valve so that the high-temperature cooling water stored in the heat storage tank is supplied to the internal combustion engine. Warm-up control means for supplying heat to the heat-collecting means, wherein the warm-up control means controls the flow rate regulating valve when the cooling water in the heat collecting means is equal to or lower than a predetermined temperature, and It is assumed that the flow rate of the cooling water is adjusted to a predetermined minute flow rate.
[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 to prevent the temperature of the cooling water flowing in the internal combustion engine from rapidly dropping, The low-temperature cooling water can be gradually warmed. Thus, for example, in a device that performs fuel injection control or the like based on the temperature of the cooling water flowing through the internal combustion engine, it is possible to suppress disturbance in injection amount control or the like due to a rapid decrease in the 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 the cooling water for heat collection and the cooling water for warming up from the temperature of the cooling water for warming up before the merging. And
[0011]
Preferably, the apparatus further comprises a water temperature sensor for detecting a temperature of the cooling water in the heat collecting means, wherein the warm-up control means measures a temperature of the cooling water in the heat collecting means based on a detection result of the water temperature sensor. It shall be.
[0012]
Desirably, 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 cooling water for heat collection.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a configuration diagram showing an 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, whereby the engine 10 is cooled. An engine pump 14 driven by a crankshaft (not shown) of the engine 10 is connected to an upstream side of the cooling water passage 12, and 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 a downstream side of the cooling water passage 12 of the engine 10, and is configured such that cooling water flows to a suction side of the engine pump 14 via a thermostat valve 18 and a cooling water passage 20. ing. The thermostat valve 18 is connected to a water inlet of a radiator 24 via a cooling water passage 22, and a water outlet of the radiator 24 is connected to a suction side of the engine pump 14 via a 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 merging.
[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 a predetermined temperature Ts, the thermostat valve 18 closes the cooling water passage 20. When the cooling water temperature is equal to or lower than the predetermined temperature Ts, the cooling water passage 16 is closed and the cooling water passage 16 is connected to the cooling water passage 20.
[0017]
Therefore, when the temperature of the cooling water is higher than the predetermined temperature Ts during the operation of the engine 10, the cooling water is supplied to the engine pump 14 → the cooling water passage 12 → the cooling water passage 16 → the thermostat valve 18 → the cooling water passage 22 → The coolant circulates through a closed circuit of the radiator 24 → the cooling water passage 26 → the engine pump 14, and the cooling water heated in the engine 10 is cooled when passing through the radiator 24.
[0018]
On the other hand, during the operation of the engine 10, when the cooling water temperature is equal to or lower than the predetermined temperature Ts, the cooling water is supplied from the engine pump 14 → the cooling water passage 12 → the cooling water passage 16 → the thermostat valve 18 → the cooling water passage 20 → the engine. Circulates through the closed circuit of the pump 14.
[0019]
The cooling water passage 12 of the engine 10 is also connected to a circuit different from the above-described circuit. That is, on the downstream side of the cooling water passage 12, a cooling water passage 28, a three-way switching valve 30 as a flow control 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 cooling water passage 26 is connected to the engine pump 14. Thereby, the pump 14 for the engine → the cooling water passage 12 of the engine → the cooling water passage 28 → the three-way switching valve 30 → the cooling water passage 32 → the heat storage tank 36 → the heat storage tank pump 38 → the cooling water passage 40 → the cooling water passage 26 → A closed circuit in which the warm-up cooling water circulating with the engine pump 14 flows is formed.
[0020]
This closed circuit is used when the high-temperature cooling water heated by the engine 10 is introduced into the heat storage tank 36 and stored therein, or when the engine 10 is started, the engine 10 is warmed up by the high-temperature cooling water stored in the heat storage tank 36. This is the 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, since the engine pump 14 is a pump driven by the crankshaft of the engine 10 as described above, it 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 heat collecting means for collecting heat from the cooling water heated by the engine 10.
[0021]
Thereby, 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 42 → the heater core 44 → the cooling water passage 40 → the cooling water passage 26 → the engine pump 14 circulates. 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 flow path of cooling water.
[0023]
When the mode selection switch of the air conditioner (not shown) 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, Drive pump 46 is driven. As a result, in addition to the flow of the cooling water described above, a part of the cooling water flowing out of the cooling water passage 12 of the engine 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. The flow then flows from the cooling water passage 44 to the cooling water passage 40 and merges with the cooling water passage 26. The heater core 44 takes heat from the high-temperature cooling water heated by the engine, and uses the heat for warming up the vehicle interior.
[0024]
Next, the operation of storing high-temperature cooling water in the heat storage tank 36 to store heat and the 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, the heat storage is performed immediately after the engine 10 is stopped. That is, in response to an engine stop signal (for example, an ignition switch OFF signal), the warm-up control unit 50 controls the three-way switching valve 30 so as to connect the cooling water passage 28 and the cooling water passage 32, and also stores the heat for the heat storage. The pump 38 is operated. Thereby, the cooling water is supplied to the cooling water passage 12 of the engine → 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 passage 26 flows through a closed circuit that returns to the cooling water passage 12 via the engine pump 14. However, in this case, since the engine 10 has been stopped, the engine pump 14 is not operating. That is, the cooling water flowing through the cooling water passage 12 of the engine is flowed by the heat storage pump 38.
[0026]
Next, warming 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 the 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 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 a closed circuit that returns to the heat storage tank 36 via 34. Further, since the engine 10 is not yet cranked, the engine pump 14 is not operated. Therefore, the cooling water flowing through the cooling water passage 12 of the engine is flown by the heat storage tank pump 38. During this warm-up, it is desirable that the cooling water does not circulate through the heater core 44. That is, the warming-up is efficiently performed by avoiding a decrease in the cooling water temperature due to the heat collection of the heater core 44.
[0027]
As described above, it is desirable that the warm-up be performed before the engine 10 is started, and that the engine 10 be started after the engine 10 reaches a desired temperature by 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, although the temperature of the engine 10 reaches a desired temperature and the temperature of the cooling water for warm-up circulating between the engine 10 and the heat storage tank 36 is high, the temperature of the cooling water inside the heater core 44 remains low. It is. If the cooling water in the heater core 44 is injected into the cooling water for warming up in this state, the temperature of the injected cooling water, that is, the temperature of the cooling water flowing into the engine 10 rapidly decreases, and the engine cooling water is cooled. May adversely affect various engine controls based on the temperature of the engine.
[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 inside 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. 1 are denoted by the same reference numerals in FIG.
[0030]
When an instruction to start the engine 10 is input, for example, when an engine start key is input by a driver, the engine 10 is warmed up in step 1. After the warm-up is sufficiently performed in step 1, the engine 10 is started in step 2.
[0031]
After the start of the engine 10, in step 3, the three-way switching valve 30 is controlled such that the flow rate of the cooling water for heat collection circulating between the engine 10 and the heater core 44 becomes smaller than a predetermined flow rate. As the predetermined flow rate, when the low-temperature cooling water inside the heater core 44 joins 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 the joining decreases. The value is set as a theoretically calculated value that does not adversely affect the control of the engine 10, or as a value obtained by an experiment.
[0032]
Next, in step 4, the temperature of the cooling water in the heater core 44 is compared with the temperature of the cooling water for warm-up. If the two 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 flow rate restriction of the cooling water for cooling is released, and the cooling for heat collecting is performed as necessary for warming up the passenger compartment. Fully open the water. If the two 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, where the flow rate of the cooling water for heat collection is set to be smaller than the predetermined flow rate. I do.
[0033]
The temperature of the cooling water in the heater core 44 may be theoretically calculated based on a measured value obtained from the heater core water temperature sensor 52, or the flow rate and circulation time of the cooling water for heat collection, or An experiment may be performed according to the flow rate and circulation time of the cooling water for heat collection, 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 in which a rapid decrease in temperature of cooling water flowing in the internal combustion engine is prevented.
[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 a warm-up control unit.
[Explanation of symbols]
Reference Signs List 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 that stores high-temperature cooling water heated by the internal combustion engine,
Heat collecting means for collecting heat from the cooling water;
Cooling water circulating between the internal combustion engine and the heat storage tank, and cooling water circulating between the internal combustion engine and the heat collecting means; Flow rate adjusting valve for adjusting the flow rate of cooling water for cooling and the cooling water for heat collection,
Warm-up control means for controlling the flow rate regulating valve, supplying high-temperature cooling water stored in the heat storage tank to the internal combustion engine to warm it up,
Has,
When the cooling water in the heat collecting means is equal to or lower than a predetermined temperature, the warm-up control means controls the flow rate control valve to adjust the flow rate of the cooling water for heat collection to a predetermined minute flow rate. apparatus. The cooling device for an internal combustion engine according to claim 1,
The cooling device for an internal combustion engine, wherein the predetermined temperature is a temperature of the warm-up cooling water. The 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 the cooling water for heat collection and the cooling water for warming up from the temperature of the cooling water for warming up before merging. Cooling device for internal combustion engine. The cooling device for an internal combustion engine according to any one of claims 1 to 3,
Further comprising 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 unit measures a temperature of cooling water in the heat collecting unit based on a detection result of the water temperature sensor. The cooling device for an internal combustion engine according to any one of claims 1 to 3,
The cooling device for an internal combustion engine, wherein the warm-up control means determines a temperature of the cooling water in the heat collecting means based on an experimental result obtained in advance according to a flow rate and a circulation time of the cooling water for heat collection.

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