JP2006233944A - Warming-up system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique that can suitably warm up an internal combustion engine provided with an engine heating medium passage where the heating medium flows. <P>SOLUTION: There is provided a heat accumulation tank that stores the heating medium inside while keeping the heat in the heating medium. The heating medium in the engine heating medium passage provided in the internal combustion engine is discharged into the heat accumulation tank after stopping the internal combustion engine (S104) and is stored in the heat accumulation tank. After the temperature of the internal combustion engine has risen to a certain or higher level after starting the internal combustion engine, the heating medium is introduced into the engine heating medium passage from the heat accumulation tank. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a warm-up system for an internal combustion engine, and more particularly to a warm-up system for an internal combustion engine having an engine heat medium passage provided in the internal combustion engine and through which a heat medium flows.

  In an internal combustion engine cooling apparatus that cools an internal combustion engine with cooling water, when the internal combustion engine needs to be cooled, the cooling water is allowed to flow through an engine cooling water passage provided in the internal combustion engine, thereby cooling the internal combustion engine. Is not required, the cooling water in the engine cooling water passage is discharged to the cooling water tank so that the cooling water does not flow through the engine cooling water passage (for example, see Patent Document 1). ).

In addition, it has temperature detection means for detecting the temperature in the vicinity of the combustion chamber of the internal combustion engine. There is also known a technique for returning the cooling water in the cooling water tank to the engine cooling water passage when the temperature in the vicinity of the combustion chamber is equal to or higher than a set value (for example, see Patent Document 2).
JP 2000-220457 A Japanese Utility Model Publication No. 1-80622 Japanese Utility Model Publication No. 3-26255 Japanese Utility Model Publication No. 3-26254 Japanese Patent Laid-Open No. 10-77839

  When the engine heat medium passage through which the heat medium flows is provided in the internal combustion engine, the internal combustion engine is cooled by flowing the heat medium through the engine heat medium passage, thereby suppressing the excessive temperature rise of the internal combustion engine. Yes. However, if a heat medium is present in the engine heat medium passage when the internal combustion engine is started, the warm-up efficiency of the internal combustion engine may be reduced.

  This invention is made in view of the said problem, Comprising: It aims at providing the technique which can warm up more suitably the internal combustion engine provided with the engine heat-medium channel | path through which a heat medium flows. To do.

  The present invention includes a heat storage tank that retains the heat medium while keeping the heat medium, and discharges the heat medium in the engine heat medium passage provided in the internal combustion engine to the heat storage tank after the internal combustion engine is stopped. Then, after the internal combustion engine is started, the temperature of the internal combustion engine rises to a certain level or more, and then the heat medium is introduced from the heat storage tank into the engine heat medium passage.

More specifically, the internal combustion engine warm-up system according to the present invention is:
A heat storage tank for storing the heat medium while keeping heat,
An engine heat medium passage provided in the internal combustion engine and through which the heat medium flows,
After the internal combustion engine is stopped, the heat medium in the engine heat medium passage is discharged into the heat storage tank, and after a predetermined introduction condition is satisfied after the internal combustion engine is started, the heat medium in the heat storage tank is changed to the engine heat medium. It is introduced into the passage.

Here, the prescribed introduction condition is a condition for determining that the temperature of the internal combustion engine has risen to some extent. For example, the specified introduction condition may be a time when the elapsed time from the start of the internal combustion engine becomes equal to or longer than the specified start time.

  In the present invention, after the internal combustion engine is stopped, the heat medium is discharged from the engine heat medium passage to the heat storage tank. Therefore, the heat medium having a relatively high temperature heated during the operation of the internal combustion engine is stored while being kept warm in the heat storage tank. Furthermore, when the internal combustion engine is started, there is almost no heat medium in the engine heat medium passage, so that warming up of the internal combustion engine can be further promoted.

  Further, after the internal combustion engine is started, when the heat medium is introduced from the heat storage tank into the engine heat medium passage, the heat medium that has been kept at a relatively high temperature is introduced. Therefore, it is possible to suppress an excessive decrease in the temperature of the internal combustion engine by introducing the heat medium into the engine heat medium passage.

  Therefore, according to the present invention, the internal combustion engine provided with the engine heat medium passage through which the heat medium flows can be more suitably warmed up.

  In the present invention, when the engine internal temperature detection means for detecting the temperature of the heat medium in the engine heat medium passage (hereinafter referred to as engine heat medium temperature) is further provided, the engine temperature detection means after the internal combustion engine is stopped. When the engine internal heat medium temperature detected by the above is lowered to a temperature equal to or lower than the specified heat medium temperature, discharge of the heat medium from the engine heat medium passage to the heat storage tank may be started.

  Here, the specified heat medium temperature can suppress an excessive temperature drop of the internal combustion engine even when the heat medium is introduced into the engine heat medium passage after the internal combustion engine is restarted. At a temperature that is not less than the lower limit value of the temperature, and it is considered that it takes a specified time or more for the internal heat engine temperature to decrease to the specified heat medium temperature after the internal combustion engine is stopped. is there. The specified time here is a time during which it can be determined that the temperature of the internal combustion engine does not decrease to a temperature that requires warm-up at the start if the stop period of the internal combustion engine is shorter than the specified time. The specified time and the specified heat medium temperature may be determined based on the internal heat medium temperature at the time when the internal combustion engine stops.

  When the discharge of the heat medium from the engine heat medium passage to the heat storage tank is started immediately after the internal combustion engine is stopped, the internal combustion engine has a short stop period and the temperature of the internal combustion engine reaches a temperature that requires warm-up when the internal combustion engine is started. Even if it does not decrease, the heat medium may be discharged from the engine heat medium passage to the heat storage tank. That is, there is a possibility that the heat medium is moved unnecessarily.

  On the other hand, since the temperature of the heat medium in the engine decreases with time after the internal combustion engine is stopped, the heat medium is discharged from the engine heat medium passage to the heat storage tank when an excessively long time has elapsed after the internal combustion engine is stopped. When is started, there is a possibility that a heat medium having an excessively low temperature is stored in the heat storage tank. As a result, when the heat medium is introduced from the heat storage tank into the engine heat medium passage after the internal combustion engine is started, an excessive temperature drop of the internal combustion engine is likely to occur.

Therefore, as described above, after the internal combustion engine is stopped, the heat from the engine heat medium passage to the heat storage tank is reduced when the temperature of the heat medium in the engine detected by the temperature detecting means in the engine decreases to a specified heat medium temperature or less. Start discharging media. As a result, the discharge of the heat medium from the engine heat medium passage to the heat storage tank is started after a lapse of a specified time or longer after the internal combustion engine is stopped. That is, even when the internal combustion engine is started, if the stop period of the internal combustion engine is so short that it is not necessary to warm up the internal combustion engine, the heat medium is discharged from the engine heat medium passage to the heat storage tank. Not done. Furthermore, it is possible to suppress an excessively long time from when the internal combustion engine is stopped until the start of the discharge of the heat medium from the engine heat medium passage to the heat storage tank. That is, it is possible to suppress the temperature of the heat medium stored in the heat storage tank from becoming excessively low.

  Therefore, according to the above control, it is possible to suppress unnecessary movement of the heat medium, and to prevent the heat medium having an excessively low temperature from being introduced into the engine heat medium passage after the internal combustion engine is started. I can do it. As a result, the consumption of energy used for the movement of the heat medium between the engine heat medium passage and the heat storage tank can be suppressed, and the heat medium is transferred from the heat storage tank to the engine heat medium passage after the internal combustion engine is started. An excessive temperature drop of the internal combustion engine when introduced can be suppressed.

  In the present invention, the discharge of the heat medium from the engine heat medium passage to the heat storage tank may be prohibited until the specified stop time elapses after the internal combustion engine is stopped.

  As described above, if the discharge of the heat medium from the engine heat medium passage to the heat storage tank is started immediately after the internal combustion engine is stopped, the heat medium may be moved unnecessarily. Therefore, as described above, from the time when the internal combustion engine stops until the specified stop time elapses, the heat medium from the engine heat medium passage to the heat storage tank regardless of the temperature of the heat medium in the engine heat medium passage. Is prohibited. Here, the specified stop time is a relatively short time, and even when the internal combustion engine is stopped for the specified stop time, it can be determined that the temperature drop of the internal combustion engine is small. The specified stop time is a predetermined time.

  According to such control, when the internal combustion engine is stopped for a certain period of time, the heat medium is discharged from the engine heat medium passage to the heat storage tank. Therefore, unnecessary movement of the heat medium can be suppressed.

  In the present invention, when the automatic stop / starting means for automatically stopping / starting the internal combustion engine is further provided, and when the internal combustion engine is stopped by the automatic stop / starting means, the engine heat medium passage leads to the heat storage tank. The discharge of the heat medium may be prohibited.

  The automatic stop / start means automatically stops the internal combustion engine when a prescribed condition is satisfied, for example, when a vehicle equipped with the internal combustion engine stops or decelerates. When the internal combustion engine is stopped by such automatic stop / start means, it can be determined that the period until the internal combustion engine is started, that is, the stop period of the internal combustion engine is relatively short. Therefore, in such a case, discharge of the heat medium from the engine heat medium passage to the heat storage tank is prohibited. Thereby, unnecessary movement of the heat medium can be suppressed.

  In the present invention, the integrated injection amount calculating means for calculating the integrated amount of the fuel injection amount from the start of the internal combustion engine (hereinafter referred to as the integrated injection amount), and the integrated injection calculated by the integrated injection amount calculating means. And engine temperature estimation means for estimating the temperature of the internal combustion engine based on the quantity.

  In the present invention, when the internal combustion engine is started, since there is no heat medium in the engine heat medium passage, the temperature of the internal combustion engine cannot be estimated based on the heat medium temperature in the engine. Therefore, as described above, the temperature of the internal combustion engine is estimated based on the integrated injection amount.

  As the integrated injection amount increases, the amount of heat generated by the combustion of fuel in the internal combustion engine also increases, so the temperature of the internal combustion engine inevitably increases. Accordingly, it is possible to estimate the amount of temperature increase from the start of the internal combustion engine from the integrated injection amount. The temperature at the start of the internal combustion engine can be estimated from the elapsed time from the time when the internal combustion engine is stopped, the outside air temperature, and the like. Therefore, the temperature of the internal combustion engine after starting can be estimated based on these.

  The heat medium is introduced into the engine heat medium passage when the start of introduction of the heat medium from the heat storage tank to the engine heat medium passage after the start of the internal combustion engine is too early, that is, when the temperature rise of the internal combustion engine is insufficient. If it does, there exists a possibility that the temperature of an internal combustion engine may fall excessively by being cooled with this heat carrier. On the other hand, if the start of introduction of the heat medium from the heat tank to the engine heat medium passage after the start of the internal combustion engine is too late, the internal combustion engine may be overheated before the internal combustion engine is cooled by the heat medium. is there.

  Therefore, when the temperature of the internal combustion engine is estimated by the engine temperature estimating means as described above, the specified introduction condition is satisfied when the temperature of the internal combustion engine becomes equal to or higher than the specified engine temperature after the internal combustion engine is started. You may judge that you did. That is, introduction of the heat medium from the heat storage tank to the engine heat medium passage may be started when the temperature of the internal combustion engine rises to a specified engine temperature or higher.

  Here, the specified engine temperature is higher than a temperature at which the temperature of the internal combustion engine can be determined to decrease excessively when the heat medium is introduced from the heat storage tank into the engine heat medium passage, and from the heat storage tank to the engine heat medium passage. When the heat medium is not introduced, the temperature is lower than a temperature at which it can be determined that the internal combustion engine is overheated. The prescribed engine temperature can be determined in advance by experiments or the like.

  According to the above control, the temperature after starting the internal combustion engine is estimated, and introduction of the heat medium from the heat storage tank to the engine heat medium passage is started when the estimated temperature rises above the specified engine temperature. Thus, the introduction of the heat medium can be started at a more suitable timing. Therefore, it is possible to suppress an excessive temperature drop of the internal combustion engine and an excessive temperature rise of the internal combustion engine.

  In the present invention, when the lubricating oil temperature detecting means for detecting the temperature of the lubricating oil supplied to the internal combustion engine is further provided, the temperature of the lubricating oil detected by the lubricating oil temperature detecting means is defined after the internal combustion engine is started. It may be determined that the prescribed introduction condition is satisfied when the temperature of the lubricating oil becomes equal to or higher. That is, introduction of the heat medium from the heat storage tank to the engine heat medium passage may be started when the temperature of the lubricating oil rises to the specified lubricating oil temperature or higher.

  When the temperature of the lubricating oil is relatively low, the internal combustion engine is cooled by the lubricating oil. Therefore, even if the heat medium does not exist in the engine heat medium passage, the excessive temperature rise of the internal combustion engine can be suppressed. I can do it. However, if the temperature of the lubricating oil becomes relatively high, it becomes difficult to cool the internal combustion engine with the lubricating oil, and thus there is a risk of overheating of the internal combustion engine in the absence of a heat medium in the engine heat medium passage. .

  In addition, if the start of introduction of the heat medium from the heat storage tank to the engine heat medium passage after the start of the internal combustion engine is too early, the temperature of the internal combustion engine may be excessively decreased due to cooling by the heat medium. .

  Therefore, as described above, after the internal combustion engine is started, introduction of the heat medium from the heat storage tank to the engine heat medium passage is started when the temperature of the lubricating oil rises to the specified lubricating oil temperature or higher.

  Here, the specified lubricating oil temperature is the lower limit value of the temperature at which it is possible to determine that the temperature of the internal combustion engine is unlikely to decrease excessively even when the heat medium is introduced from the heat storage tank into the engine heat medium passage. The temperature is equal to or lower than the upper limit value of the temperature at which overheating of the internal combustion engine can be suppressed even when no heat medium is present in the engine heat medium passage. The prescribed lubricating oil temperature can be determined in advance by experiments or the like.

According to the above control, when the temperature of the lubricating oil rises to the specified lubricating oil temperature or higher, introduction of the heat medium from the heat storage tank to the engine heat medium passage is started more favorably. You can start at the right time. Therefore, it is possible to suppress an excessive temperature drop of the internal combustion engine and an excessive temperature rise of the internal combustion engine.

  In the present invention, when further provided with a tank temperature detection means for detecting the temperature of the heat medium in the heat storage tank (hereinafter referred to as the tank heat medium temperature), the engine heat from the heat storage tank after the start of the internal combustion engine. The introduction start timing of the heat medium into the medium passage may be delayed as the temperature of the heat medium in the tank detected by the tank temperature detecting means is lower.

  The lower the heat medium temperature in the tank, the more likely the temperature of the internal combustion engine to decrease excessively when the heat medium is introduced from the heat storage tank into the engine heat medium passage. Therefore, as described above, the heat medium introduction start timing from the heat storage tank to the engine heat medium passage after the start of the internal combustion engine is made slower as the tank heat medium temperature is lower. As a result, the lower the heat medium temperature in the tank, the higher the temperature of the internal combustion engine becomes, and the heat medium is introduced into the engine heat medium passage.

  Therefore, according to the above control, it is possible to further suppress an excessive temperature drop of the internal combustion engine when the heat medium is introduced from the heat storage tank into the engine heat medium passage after the internal combustion engine is started.

  With the internal combustion engine warm-up system according to the present invention, it is possible to more suitably warm up the internal combustion engine provided with the engine heat medium passage through which the heat medium flows.

  Hereinafter, specific embodiments of a warm-up system for an internal combustion engine according to the present invention will be described with reference to the drawings.

<Schematic configuration of internal combustion engine and its cooling water system and lubricating oil system>
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine according to the present embodiment and its cooling water system and lubricating oil system. The internal combustion engine 1 is provided with an engine coolant passage 2 through which coolant flows.

  One end of the cooling water passage 3 provided outside the internal combustion engine 1 is connected to one end of the engine cooling water passage 2. The other end of the cooling water passage 3 is connected to the other end of the engine cooling water passage 2. An engine-related element and a radiator (not shown) that need to be cooled by the cooling water are provided in the middle of the cooling water passage 3.

  In the vicinity of the other end portion of the cooling water passage 3, a cooling water pump 4 that pumps the cooling water from one end side to the other end side of the cooling water passage 3 is provided. The cooling water pump 4 is a pump that operates using the rotation of the crankshaft of the internal combustion engine 1 as a driving force. By operating the cooling water pump 4, the cooling water circulates through the engine cooling water passage 2 and the cooling water passage 3. A circulation passage formed by the engine coolant passage 2 and the coolant passage 3 is referred to as a coolant circulation passage 5.

  The internal combustion engine 1 is also provided with a heat storage tank 6. The heat storage tank 6 and the cooling water passage 3 are communicated with each other through a tank side cooling water passage 7. One end of the tank side cooling water passage 7 is connected to the cooling water passage 3, and the other end is inserted into the heat storage tank 6. The heat storage tank 6 is a tank that retains cooling water while keeping the temperature. The volume of the heat storage tank 6 is equal to or greater than the volume of the cooling water circulation passage 5.

One end of the engine side air passage 11 is connected to the middle of the engine cooling water passage 2. The engine side air passage 11 is provided with an engine side air vent valve 12 and an engine side air pump 13. On the other hand, one end of a tank side air passage 14 is connected to the heat storage tank 6. The tank side air passage 14 is provided with a tank side intake vent valve 15 and a tank side air pump 16. The control method of the engine side intake vent valve 12, the engine side air pump 13, the tank side air vent valve 15, and the tank side air pump 16 will be described later.

  Further, an oil pan 8 is installed below the internal combustion engine 1. One end of an oil supply passage 9 is connected to the oil pan 8. The other end of the oil supply passage 9 is connected to the upper part of the internal combustion engine 1. An oil pump 10 that pumps oil (lubricating oil) from the oil pan 8 side to the internal combustion engine 1 side is provided in the middle of the oil supply passage 9. By operating the oil pump 10, oil is sucked up from the oil pan 8, and the oil is supplied to the internal combustion engine 1 through the oil supply passage 9.

  The engine cooling water passage 2 is provided with an engine water temperature sensor 17 that outputs an electrical signal corresponding to the temperature of the cooling water in the engine cooling water passage 2 (hereinafter referred to as engine water temperature). The heat storage tank 6 is provided with a tank water temperature sensor 18 that outputs an electrical signal corresponding to the temperature of the cooling water in the heat storage tank (hereinafter referred to as the tank water temperature). Further, the oil pan 8 is provided with an oil temperature sensor 19 that outputs an electrical signal corresponding to the oil temperature in the oil pan 8.

  The internal combustion engine 1 is also provided with an ECU 20 for controlling the internal combustion engine 1. The ECU 20 is a unit that controls the operation state of the internal combustion engine 1 in accordance with the operation conditions of the internal combustion engine 1 and the request of the driver.

  The ECU 20 is electrically connected with an engine water temperature sensor 17, a tank water temperature sensor 18, an oil temperature sensor 19, and an ignition switch 21. These outputs are input to the ECU 20. Further, the ECU 20 is electrically connected with an engine side air vent valve 12 and an engine side air pump 13, a tank side air vent valve 15, a tank side air pump 16, and an oil pump 10. These are controlled by the ECU 20.

  Further, a fuel injection valve of the internal combustion engine 1 is also electrically connected to the ECU 20, and this fuel injection valve is also controlled by the ECU 20.

<Cooling water movement control>
In the present embodiment, the cooling water is circulated in the cooling water circulation passage 5 during the operation of the internal combustion engine 1. When the internal combustion engine 1 is stopped, the cooling water in the cooling water circulation passage 5 is discharged into the heat storage tank 6 at a timing described later. Then, after the internal combustion engine 1 is started again, the cooling water in the heat storage tank 6 is introduced into the cooling water circulation passage 5 at a timing described later.

  Here, a method for moving the cooling water as described above will be described. When the cooling water in the cooling water circulation passage 5 is discharged into the heat storage tank 6, first, the engine side air vent valve 12 and the tank side air vent valve 15 are opened. Then, the air in the heat storage tank 6 is drawn by operating the tank side air pump 16, and the air is released from the other end of the tank side air passage 14. Thus, the air is drawn out from the heat storage tank 6, whereby the cooling water in the cooling water circulation passage 5 is drawn into the heat storage tank 6 through the tank-side cooling water passage 7. After the cooling water in the cooling water circulation passage 5 is drawn into the heat storage tank 6, the engine side air vent valve 12 and the tank side air vent valve 15 are closed.

On the other hand, when the cooling water in the heat storage tank 6 is introduced into the cooling water circulation passage 5, the engine side air vent valve 12 and the tank side air vent valve 15 are first opened as described above. Then, by operating the engine side air pump 13, the air in the cooling water circulation passage 5 is extracted, and the air is discharged from the other end of the engine side air passage 13. Thus, the air is drawn out from the cooling water circulation passage 5, whereby the cooling water in the heat storage tank 6 is drawn into the cooling water circulation passage 5 through the tank side cooling water passage 7. After the cooling water in the heat storage tank 6 is drawn into the cooling water circulation passage 5, the engine side air vent valve 12 and the tank side air vent valve 15 are closed.

  By such control, the cooling water in the cooling water circulation passage 5 can be discharged into the heat storage tank 6, and the cooling water in the heat storage tank 6 can be introduced into the cooling water circulation passage 5.

  In the present embodiment, as described above, the cooling water is discharged from the cooling water circulation passage 5 to the heat storage tank 6 after the internal combustion engine 1 is stopped. Therefore, the relatively high temperature cooling water heated during the operation of the internal combustion engine 1 is stored in the heat storage tank 6 while being kept warm. Further, when the internal combustion engine 1 is started, there is almost no cooling water in the engine cooling water passage 2, so that warming up of the internal combustion engine 1 is more easily promoted.

  When the cooling water is introduced from the heat storage tank 6 into the cooling water circulation passage 5 after the internal combustion engine 1 is started, the cooling water that has been kept at a relatively high temperature is introduced. Therefore, it is possible to prevent the temperature of the internal combustion engine 1 from being excessively lowered by introducing the cooling water into the engine cooling water passage 2.

  Therefore, according to the present embodiment, the internal combustion engine 1 can be warmed up more suitably.

<Cooling water discharge control>
Next, the control flow of the cooling water discharge control for discharging the cooling water from the cooling water circulation passage 5 to the heat storage tank 6 after the internal combustion engine 1 is stopped will be described based on the flowchart shown in FIG. This routine is stored in advance in the ECU 20, and is a routine that is repeated at regular intervals while the ECU 20 is ON.

  In this routine, the ECU 20 first determines in step S101 whether the ignition switch 21 has been turned off. That is, it is determined whether or not the internal combustion engine 1 has been stopped. If an affirmative determination is made in S101, the ECU 20 proceeds to S102, and if a negative determination is made, the ECU 20 once ends the execution of this routine.

  In S102, the ECU 20 determines whether or not the elapsed time Δts after the ignition switch 21 is turned off, that is, the elapsed time Δts after the internal combustion engine 1 is stopped is equal to or longer than the specified stop time Δt0. Here, the specified stop time Δt0 is a relatively short time, and is a time when it can be determined that the temperature drop of the internal combustion engine 1 is small even when the internal combustion engine 1 stops at the specified stop time Δt0. The specified stop time Δt0 is a predetermined time. If an affirmative determination is made in S102, the ECU 20 proceeds to S103, and if a negative determination is made, the ECU 20 once ends this routine.

In S103, the ECU 20 determines whether or not the engine water temperature Twe has decreased to a specified cooling water temperature Twe0 or lower. Here, the specified cooling water temperature Twe0 suppresses an excessive temperature drop of the internal combustion engine 1 even when the cooling water is introduced into the engine cooling water passage 2 after the internal combustion engine 1 is restarted. It takes a time longer than a specified time for the internal water temperature Twe to fall to the specified cooling water temperature Twe0 after the internal combustion engine 1 is stopped. It is the temperature considered. The specified time here is a time during which it can be determined that the temperature of the internal combustion engine 1 does not decrease to a temperature that requires warm-up at the start if the stop period of the internal combustion engine 1 is shorter than the specified time. In this embodiment, the relationship between the engine water temperature and the specified time when the internal combustion engine 1 is stopped and the specified cooling water temperature Twe0 is stored in advance in the ECU as a map, and the specified cooling water temperature is calculated from the map. Twe0 is determined. If an affirmative determination is made in S103, the ECU 20 proceeds to S104. On the other hand, if a negative determination is made in S103, the ECU 20 determines that the engine water temperature Twe has not decreased to the specified cooling water temperature Twe0, and repeats S103.

  In S104, the ECU 20 starts discharging the cooling water from the cooling water circulation passage 5 to the heat storage tank 6 by the above method. Thereafter, the ECU 20 once ends the execution of this routine.

  According to the control routine described above, even when the internal combustion engine 1 is stopped, the heat storage tank 6 is connected from the cooling water circulation passage 5 until the specified stop time ΔT0 elapses after the internal combustion engine 1 is stopped. Cooling water is not allowed to be discharged.

  Further, after the internal combustion engine 1 is stopped, the discharge of the cooling water from the cooling water circulation passage 5 to the heat storage tank 6 is started when the in-engine water temperature Twe is lowered to the specified cooling water temperature Twe0 or lower. Thereby, the discharge of the cooling water from the cooling water circulation passage 5 to the heat storage tank 6 is started after a time equal to or longer than a predetermined time has elapsed since the internal combustion engine 1 was stopped. That is, even when the internal combustion engine 1 is started, if the stop period of the internal combustion engine 1 is so short that it is not necessary to warm up the internal combustion engine 1, the cooling from the cooling water circulation passage 5 to the heat storage tank 6 is performed. There is no water discharge. Furthermore, it is possible to suppress an excessively long time from when the internal combustion engine 1 is stopped until the cooling water starts to be discharged from the cooling water circulation passage 5 to the heat storage tank 6. . That is, it is possible to suppress the temperature of the cooling water stored in the heat storage tank 6 from being excessively low.

  Therefore, according to the present embodiment, unnecessary movement of the cooling water can be suppressed, and the cooling water having an excessively low temperature is introduced into the engine cooling water passage 2 after the internal combustion engine 1 is started. Can be suppressed. As a result, the consumption of energy used for the movement of the cooling water between the engine cooling water passage 2 and the heat storage tank 6 can be suppressed, and the cooling water circulation passage 5 from the heat storage tank 6 after the internal combustion engine 1 is started. It is possible to suppress an excessive temperature drop of the internal combustion engine 1 when a heat medium is introduced into the internal combustion engine.

<Modified example of cooling water discharge control>
Here, as a modified example of the cooling water discharge control, a case will be described in which the internal combustion engine 1 is applied to a system that automatically stops and starts the internal combustion engine, such as an economy running system or a hybrid system.

  When the internal combustion engine 1 is automatically stopped by the system as described above, it can be determined that the period until the internal combustion engine 1 is started, that is, the stop period of the internal combustion engine 1 is relatively short. As described above, when the stop period of the internal combustion engine 1 is relatively short, there is a high possibility that the temperature of the internal combustion engine 1 does not decrease to a temperature that requires warm-up at the time of start-up.

  Therefore, when the internal combustion engine 1 is automatically stopped by the above system, the discharge of the cooling water from the cooling water circulation passage 5 to the heat storage tank 6 is prohibited. Thereby, unnecessary movement of the cooling water can be suppressed.

<Cooling water introduction control>
Next, a control flow of the cooling water introduction control for introducing the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 after the internal combustion engine 1 is started will be described based on the flowchart shown in FIG. Similarly to the above, this routine is also stored in advance in the ECU 20, and is a routine that is repeated at regular intervals while the ECU 20 is ON.

  In this routine, the ECU 20 first determines in step S201 whether or not the ignition switch 21 is turned on. That is, it is determined whether or not the internal combustion engine 1 has been started. If an affirmative determination is made in S201, the ECU 20 proceeds to S202, and if a negative determination is made, the ECU 20 once ends the execution of this routine.

  In S202, the ECU 20 estimates a starting engine temperature Tengs that is the temperature of the internal combustion engine 1 at the time when the internal combustion engine 1 is started. The starting engine temperature Tengs is estimated based on the elapsed time from the time when the internal combustion engine 1 is stopped, the outside air temperature, and the like.

  Next, the ECU 20 proceeds to S203, and calculates an integrated injection amount Qfs that is an integrated amount of the fuel injection amount from the start of the internal combustion engine 1.

  Next, the ECU 20 proceeds to S204, and estimates the temperature increase amount ΔTeng from the start of the internal combustion engine 1 from the integrated injection amount Qfs.

  Next, the ECU 20 proceeds to S205, and estimates the current temperature Teng of the internal combustion engine 1 from the starting engine temperature Tengs and the temperature increase amount ΔTeng.

  Next, the ECU 20 proceeds to S206, and determines whether or not the temperature Teng of the internal combustion engine 1 has risen to a specified engine temperature Teng0 or higher. Here, the specified engine temperature Teng0 is higher than a temperature at which it can be determined that the temperature of the internal combustion engine 1 is excessively lowered by being cooled by the heat medium when the heat medium is introduced from the heat storage tank 6 to the cooling water circulation passage 5. When the heat medium is not introduced from the heat storage tank 6 to the cooling water circulation passage 5, the temperature is lower than the temperature at which it can be determined that the internal combustion engine 1 is overheated because it is not cooled by the heat medium. The prescribed engine temperature Teng0 is a value determined in advance by experiments or the like. If an affirmative determination is made in S206, the ECU 20 proceeds to S207. On the other hand, if a negative determination is made in S206, the ECU 20 determines that the temperature Teng of the internal combustion engine 1 has not risen to the specified engine temperature Teng0, and returns to S203.

  The ECU 20 having proceeded to S207 starts the introduction of the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 by the above method. Thereafter, the ECU 20 once ends the execution of this routine.

  In the present embodiment, the cooling water discharge control is executed, so that the cooling water is discharged from the cooling water circulation passage 5 when the internal combustion engine 1 is stopped. Therefore, when the internal combustion engine 1 is started again, there is almost no cooling water in the engine cooling water passage 2, and therefore the temperature of the internal combustion engine 1 after the start cannot be estimated based on the engine water temperature. However, according to the control routine, even in such a case, the temperature of the internal combustion engine 1 after starting can be estimated.

  According to the control routine, the temperature Teng after the start of the internal combustion engine 1 is estimated, and when the estimated temperature Teng rises to the specified engine temperature Teng0 or more, the heat storage tank 6 supplies the cooling water circulation passage 5 to the cooling water circulation passage 5. Start introducing cooling water. Therefore, the introduction of the cooling water can be started at a more suitable timing. Therefore, an excessive temperature drop of the internal combustion engine 1 and an excessive temperature rise of the internal combustion engine 1 can be suppressed.

<Cooling water introduction control modification>
Here, the control routine of the modified example of the cooling water introduction control described above will be described based on the flowchart shown in FIG. This routine differs from the control routine shown in FIG. 3 only in that S306 is added, and the other steps are the same. Therefore, the same steps are denoted by the same reference numerals, and the description thereof is omitted. Further, this routine is also stored in advance in the ECU 20 as described above, and is repeated at a predetermined interval while the ECU 20 is ON.

  In this routine, after S205, the ECU 20 proceeds to S306. In S306, the ECU 20 determines the specified engine temperature Teng0 based on the tank water temperature Twt which is the temperature of the cooling water in the heat storage tank 6. Here, the specified engine temperature Teng0 is set to a higher temperature as the tank water temperature Twt is lower. Thereafter, the ECU 20 proceeds to S207.

  The lower the tank water temperature Twt, the more likely the temperature of the internal combustion engine 1 to decrease when cooling water is introduced from the heat storage tank 6 into the cooling water circulation passage 5. However, according to the control routine, after the internal combustion engine 1 is started, the introduction timing of the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 becomes slower as the tank water temperature Twt is lower. The cooling water is introduced into the cooling water circulation passage 5 after the temperature becomes higher.

  Accordingly, it is possible to further suppress an excessive temperature drop of the internal combustion engine 1 when the cooling water is introduced from the heat storage tank 6 to the cooling water circulation passage 5 after the internal combustion engine 1 is started.

  In the present embodiment, the configuration in which the cooling water is moved between the cooling water circulation passage 5 and the heat storage tank 6 by operating the engine side air pump 13 or the tank side air pump 16 has been described. Instead of the pump 13 and the tank-side air pump 16, an electric pump that can be controlled by the ECU 20 may be provided in the cooling water passage 3. In this case, the cooling water can be moved between the cooling water circulation passage 5 and the heat storage tank 6 by operating the electric pump.

  The schematic configuration of the internal combustion engine, its cooling water system and lubricating oil system, and the cooling water discharge control according to the present embodiment are the same as those of the above-described first embodiment, and thus the description thereof is omitted.

<Cooling water introduction control>
When the temperature of the oil supplied to the internal combustion engine 1 is relatively low, the internal combustion engine 1 is cooled by the oil, and therefore the internal combustion engine 1 can be operated even when there is no cooling water in the engine cooling water passage 2. Overheating can be suppressed. However, if the temperature of the oil becomes relatively high, it becomes difficult to cool the internal combustion engine 1 with the oil. Therefore, there is a risk that the internal combustion engine 1 will be overheated in the absence of cooling water in the engine cooling water passage 2. is there. In addition, if the start time of introduction of the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 after the start of the internal combustion engine 1 is too early, the temperature of the internal combustion engine 1 is excessively lowered by being cooled by the cooling water. There is a fear.

  Therefore, in this embodiment, after the internal combustion engine is started, the timing for introducing the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 is determined based on the oil temperature To in the oil pan 8. Hereinafter, the control flow of the cooling water introduction control according to the present embodiment will be described based on the flowchart shown in FIG. Similarly to the above, this routine is also stored in advance in the ECU 20, and is a routine that is repeated at regular intervals while the ECU 20 is ON.

  In this routine, the ECU 20 first determines in step S401 whether or not the ignition switch 21 is turned on. That is, it is determined whether or not the internal combustion engine 1 has been started. If an affirmative determination is made in S401, the ECU 20 proceeds to S402. If a negative determination is made, the ECU 20 once ends the execution of this routine.

In S402, the ECU 20 determines whether or not the oil temperature To in the oil pan 8 has risen to a specified oil temperature To0 or higher. Here, the specified oil temperature To0 is a temperature at which it is possible to determine that the temperature of the internal combustion engine 1 is unlikely to decrease excessively even when cooling water is introduced from the heat storage tank 6 into the cooling water circulation passage 5. The temperature is equal to or higher than the lower limit value and equal to or lower than the upper limit value of the temperature at which excessive temperature rise of the internal combustion engine 1 can be suppressed even in a state where there is no cooling water in the engine cooling water passage 2. The specified oil temperature To0 is a value determined in advance by experiments or the like. If an affirmative determination is made in S402, the ECU 20 proceeds to S403. On the other hand, if a negative determination is made in S402, the ECU 20 determines that the oil temperature To has not risen to the specified oil temperature To0, and repeats S402.

  In S403, the ECU 20 starts introducing the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 by the same method as in the first embodiment. Thereafter, the ECU 20 once ends the execution of this routine.

  According to the control routine described above, introduction of the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 is started when the oil temperature To rises to the specified oil temperature To0 or higher. Therefore, the introduction of the cooling water can be started at a more suitable timing. Therefore, an excessive temperature drop of the internal combustion engine 1 and an excessive temperature rise of the internal combustion engine 1 can be suppressed.

  In the cooling water introduction control according to the present embodiment, the specified oil temperature To0 may be determined based on the tank water cooling water temperature Twt. In this case, the lower the tank water temperature Twt, the higher the specified oil temperature To0.

  According to this, similarly to the cooling water introduction control according to the modification of the first embodiment, the introduction timing of the cooling water from the heat storage tank 6 to the cooling water circulation passage 5 after the start of the internal combustion engine 1 is the tank water temperature Twt. The lower the speed, the slower, and the cooling water is introduced into the cooling water circulation passage 5 after the temperature of the internal combustion engine 1 becomes higher.

  Accordingly, it is possible to further suppress an excessive temperature drop of the internal combustion engine 1 when the cooling water is introduced from the heat storage tank 6 to the cooling water circulation passage 5 after the internal combustion engine 1 is started.

  In the cooling water introduction control, the cooling water introduction start timing from the heat storage tank 6 to the cooling water circulation passage 5 is determined based on both the cumulative injection amount Qfs according to the first embodiment and the oil temperature To according to the second embodiment. May be.

The figure which shows schematic structure of the internal combustion engine which concerns on the Example of this invention, its cooling water system, and a lubricating oil system. The flowchart which shows the control flow of the cooling water discharge control which concerns on Example 1 of this invention. The 1st flowchart which shows the control flow of the cooling water introduction control which concerns on Example 1 of this invention. The 2nd flowchart which shows the control flow of the cooling water introduction control which concerns on the modification of Example 1 of this invention. The flowchart which shows the control flow of the cooling water introduction control which concerns on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Engine cooling water passage 3 ... Cooling water passage 5 ... Cooling water circulation passage 6 ... Heat storage tank 7 ... Tank side cooling water passage 8 ... Oil pan 9 ... Oil supply passage 10, Oil pump 11, Engine side air passage 12, Engine side air vent valve 13, Engine side air pump 14, Tank side air passage 15, Tank side air vent valve 16, Tank Side air pump 17 .. Engine water temperature sensor 18. Tank water temperature sensor 19. Oil temperature sensor 20. ECU
21. Ignition switch

Claims (7)

A heat storage tank for storing the heat medium while keeping heat,
An engine heat medium passage provided in the internal combustion engine and through which the heat medium flows,
After the internal combustion engine is stopped, the heat medium in the engine heat medium passage is discharged into the heat storage tank, and after a predetermined introduction condition is satisfied after the internal combustion engine is started, the heat medium in the heat storage tank is changed to the engine heat medium. A warming-up system for an internal combustion engine, characterized by being introduced into a passage. Engine temperature detection means for detecting the temperature of the heat medium in the engine heat medium passage,
After the internal combustion engine is stopped, the discharge of the heat medium from the engine heat medium passage to the heat storage tank is started when the temperature of the heat medium detected by the engine temperature detecting means falls below a specified heat medium temperature. The warm-up system for an internal combustion engine according to claim 1, wherein:   The internal combustion engine according to claim 1 or 2, wherein discharge of the heat medium from the engine heat medium passage to the heat storage tank is prohibited until a specified stop time elapses after the internal combustion engine is stopped. Engine warm-up system. An automatic stop / start means for automatically stopping / starting the internal combustion engine;
3. The internal combustion engine according to claim 1, wherein when the internal combustion engine is stopped by the automatic stop / start means, discharge of the heat medium from the engine heat medium passage to the heat storage tank is prohibited. Warm-up system. An integrated injection amount calculating means for calculating an integrated amount of the fuel injection amount from the start of the internal combustion engine;
Engine temperature estimating means for estimating the temperature of the internal combustion engine based on an integrated amount of the fuel injection amount calculated by the integrated injection amount calculating means,
After starting the internal combustion engine, when the temperature of the internal combustion engine estimated by the engine temperature estimating means rises to a specified engine temperature or higher, it is determined that the specified introduction condition is satisfied, and the engine is removed from the heat storage tank. 5. The warm-up system for an internal combustion engine according to claim 1, wherein introduction of the heat medium into the heat medium passage is started. Further comprising lubricating oil temperature detecting means for detecting the temperature of the lubricating oil supplied to the internal combustion engine,
After starting the internal combustion engine, when the temperature of the lubricating oil detected by the lubricating oil temperature detecting means rises to a specified lubricating oil temperature or higher, it is determined that the specified introduction condition is satisfied, and the heat storage tank 5. The warm-up system for an internal combustion engine according to claim 1, wherein introduction of the heat medium into the engine heat medium passage is started. It further comprises tank temperature detection means for detecting the temperature of the heat medium in the heat storage tank,
The introduction start timing of the heat medium from the heat storage tank to the engine heat medium passage after the start of the internal combustion engine is made slower as the temperature of the heat medium detected by the tank temperature detecting means is lower. The warm-up system for an internal combustion engine according to any one of claims 1 to 6.

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