JP2014156849A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine capable of accurately obtaining a combustion chamber temperature and a cooling water temperature inside the internal combustion engine with increased accuracy.SOLUTION: A control device of an internal combustion engine 10 concurrently estimates a combustion chamber temperature and a cooling water temperature inside the internal combustion engine on the basis of: a variation in combustion chamber wall temperatures calculated from a difference between a heat quantity transferred from combustion gas to a combustion chamber wall 34 and the heat quantity transferred from the combustion chamber wall 34 to cooling water and heat capacity of the combustion chamber wall 34; and the variation in cooling water temperatures calculated from the difference between the heat quantity transferred from the combustion chamber wall 34 to the cooling water and the heat quantity radiated from the cooling water to an outside and the heat capacity of the cooling water.

Description

  The present invention relates to a control device for an internal combustion engine.

  It is known that the temperature of the combustion chamber wall of the internal combustion engine and the temperature of the cooling water of the internal combustion engine affect the operating state of the internal combustion engine. If the combustion chamber wall temperature and the cooling water temperature can be obtained, the operation control of the internal combustion engine can be performed based on these values, so that an appropriate operation state of the internal combustion engine can be obtained.

  Conventionally, the first equation for calculating the amount of change in the temperature of the combustion chamber wall from the difference between the amount of heat received by the combustion chamber wall from the combustion gas and the amount of heat given to the cooling water from the combustion chamber wall and the heat capacity of the combustion chamber wall; Proposed to simultaneously estimate the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine based on the amount of heat received by the cooling water from the wall and the second equation for calculating the amount of change in the cooling water temperature from the heat capacity of the cooling water (For example, refer to Patent Document 1). This Patent Document 1 discloses a technique for estimating a combustion chamber wall temperature based on a heat transfer model from a combustion gas in a combustion chamber to a combustion chamber wall and a heat transfer model from the combustion chamber wall to cooling water (for example, Patent Document 2). Technology) is shown.

JP 2006-300031 A Japanese Patent No. 2666366

  In the technique described in Patent Document 1, a problem in the technique described in Patent Document 2, for example, the cooling water temperature inside the internal combustion engine (water jacket cooling water temperature) when the pump is stopped, and a water temperature sensor are detected. The problem caused by the difference from the cooling water temperature is solved. However, for example, surface heat dissipation from the internal combustion engine body and heat transfer to peripheral parts located away from the combustion chamber or water jacket are not considered, and estimation is made on the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine. An error may occur. For example, in an environment where the outside air temperature is low, there is a concern that an estimation error occurs in the cooling water temperature inside the internal combustion engine due to an increase in surface heat radiation from the internal combustion engine body.

  Moreover, since the circulation of the cooling water to the internal combustion engine is stopped when the pump is stopped, the following points are also concerned. That is, in an environment where the outside air temperature is low, the cooling water circulation stop may be ended earlier by estimating the estimated temperature of the cooling water temperature to be higher than the actual cooling water temperature. For this reason, there is a concern that warm-up in the internal combustion engine becomes insufficient and fuel consumption is deteriorated. Conversely, in an environment where the outside air temperature is high, there is a possibility that the circulation stop of the cooling water may be prolonged because the estimated temperature of the cooling water temperature is estimated to be lower than the actual cooling water temperature. For this reason, local boiling of cooling water, overheating, thermal degradation, etc. occur in the internal combustion engine, and there is a concern that reliability may be reduced.

  The present invention has been made in view of the above-described problems, and provides a control device for an internal combustion engine that can more accurately determine the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine. Objective.

  In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention is a control device for an internal combustion engine, which is a combustion chamber calculated from the difference between the amount of heat received by the combustion chamber wall from the combustion gas and the amount of heat given to the cooling water from the combustion chamber wall and the heat capacity of the combustion chamber wall. Combustion based on the amount of change in wall temperature, the difference between the amount of heat received by the cooling water from the combustion chamber wall and the amount of heat released from the cooling water to the outside, and the amount of change in cooling water temperature calculated from the heat capacity of the cooling water An estimation means for simultaneously estimating the chamber wall temperature and the cooling water temperature inside the internal combustion engine is provided. Here, the estimation of the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine by the estimation means is preferably performed when the pump is stopped. The amount of heat released from the cooling water to the outside includes the amount of heat released to the outside air and the amount of heat released to peripheral components disposed around the internal combustion engine.

  In an internal combustion engine, the temperature of the combustion gas in the combustion chamber changes according to the operating state of the internal combustion engine. When the temperature of the combustion gas changes, the amount of heat received by the combustion chamber wall changes. As a result, the combustion chamber wall temperature and the cooling water temperature change. Further, when the external temperature changes, the amount of heat released from the cooling water to the outside changes, and the cooling water temperature and the combustion chamber wall temperature change. Thus, the temperature of the combustion gas and the external temperature affect the combustion chamber wall temperature and the cooling water temperature.

  The amount of heat that the combustion chamber wall has is the difference between the amount of heat that enters the combustion chamber wall and the amount of heat that exits the combustion chamber wall, that is, “the amount of heat received by the combustion chamber wall from the combustion gas and the cooling water from the combustion chamber wall. It can be expressed as “difference from calorie”. For this reason, in the above configuration, the amount of change in the temperature of the combustion chamber wall is obtained from “the difference between the amount of heat received by the combustion chamber wall from the combustion gas and the amount of heat applied from the combustion chamber wall to the cooling water” and the “heat capacity of the combustion chamber wall”. (First relationship).

  In addition, the amount of heat that the cooling water has is the difference between the amount of heat entering the cooling water and the amount of heat emitted from the cooling water, that is, “the amount of heat received by the cooling water from the combustion chamber wall and the amount of heat released from the cooling water to the outside. Can be expressed as "difference". Therefore, in the above configuration, the amount of change in the cooling water temperature is obtained from “the difference between the amount of heat received by the cooling water from the combustion chamber wall and the amount of heat released from the cooling water to the outside” and “the heat capacity of the cooling water”. (Second relationship).

  The amount of change in the combustion chamber wall temperature changes in accordance with the cooling water temperature, and the amount of change in the cooling water temperature changes in accordance with the combustion chamber wall temperature, and the above first and second relationships influence each other. . For this reason, the change amount of the combustion chamber wall temperature and the change amount of the cooling water temperature can be solved as a differential equation of a two-dimensional variable having the combustion chamber wall temperature and the cooling water temperature as variables. By solving this differential equation, the combustion chamber wall temperature and the cooling water temperature can be obtained simultaneously.

  Here, the second relationship described above is that heat released from the cooling water to the outside (heat released to the outside air, heat released to peripheral components arranged around the internal combustion engine, etc.), that is, the internal combustion engine The relationship takes into account surface heat radiation from the engine. For this reason, the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine obtained from the first and second relationships are values that take into consideration the surface heat radiation of the internal combustion engine and the like. Therefore, the estimation error of the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine can be made smaller than in the conventional example, and the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine can be obtained more accurately. .

  In addition, when the pump is stopped, the circulation of the cooling water into the internal combustion engine is stopped. In this case also, the problem in the conventional example can be solved. That is, in an environment where the outside air temperature is low, it can be avoided that the cooling water temperature inside the internal combustion engine estimated from the first and second relationships is estimated to be higher than the actual cooling water temperature. It is possible to prevent the circulation stop from being finished early. Thereby, it can avoid that warming-up becomes insufficient in an internal combustion engine, and it can suppress the deterioration of a fuel consumption. Conversely, in an environment where the outside air temperature is high, it can be avoided that the coolant temperature inside the internal combustion engine estimated from the first and second relationships is estimated to be lower than the actual coolant temperature, Prolonged circulation stop of cooling water can be avoided. As a result, local boiling of cooling water, overheating, thermal degradation, and the like can be suppressed in the internal combustion engine, and a decrease in reliability can be avoided.

  In the present invention, the amount of heat released from the cooling water to the outside is a product of the difference between the cooling water temperature and the external temperature and a heat transfer coefficient, and the external temperature is the value at the start of the internal combustion engine. The cooling water temperature or the intake air temperature at the start of the internal combustion engine is preferably used.

  According to this configuration, in order to detect the external temperature by substituting the value detected by the cooling water temperature sensor or the intake air temperature sensor used to control the operating state of the internal combustion engine as the external temperature. There is no need to provide a dedicated sensor separately.

  Here, when the internal combustion engine is warmed up, the cooling water circulation into the internal combustion engine is stopped, so that the internal combustion engine can be warmed up quickly. Whether or not the internal combustion engine is warming up can be determined based on the cooling water temperature inside the internal combustion engine, and the internal combustion engine obtained from the first and second relationships described above can be used for this determination. It is possible to use the internal cooling water temperature.

  In the present invention, a cooling water temperature detecting means for detecting a cooling water temperature flowing out from the internal combustion engine is further provided, and when the pump is operated, the estimation means estimates the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine. It is preferable to estimate the combustion chamber wall temperature based on the cooling water temperature detected by the cooling water temperature detection means without performing the above.

  Thus, by changing the estimation method of the combustion chamber wall temperature between when the pump is stopped and when the pump is operating, the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine can be obtained more accurately. That is, when the pump is operated, there is almost no difference between the cooling water temperature obtained by the cooling water temperature detecting means and the cooling water temperature inside the internal combustion engine, so that the cooling water temperature inside the internal combustion engine can be obtained more accurately. . Moreover, it is not necessary to estimate the cooling water temperature by the estimating means, and the processing can be simplified. The combustion chamber wall temperature can be obtained more accurately from the coolant temperature detected by the coolant temperature detecting means.

  According to the present invention, the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine can be determined more accurately.

It is a figure which shows schematic structure of the control apparatus of the internal combustion engine which concerns on embodiment. It is a figure which shows schematic structure inside an internal combustion engine. It is a figure which shows typically the heat transfer from the cooling water inside an internal combustion engine to external air. It is a flowchart which shows the estimation control of a combustion chamber wall temperature and a cooling water temperature. It is a figure which shows typically the heat transfer from the cooling water inside an internal combustion engine to peripheral components.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a control device for an internal combustion engine according to an embodiment. FIG. 2 is a diagram showing a schematic configuration inside the internal combustion engine.

  As shown in FIGS. 1 and 2, the internal combustion engine 10 is a four-cycle engine, and includes a cylinder head 11 and a cylinder block 12. A water jacket 13 for circulating cooling water is formed inside the internal combustion engine 10. The water jacket 13 includes a water jacket 13 a formed inside the cylinder head 11 and a water jacket 13 b formed inside the cylinder block 12.

  As shown in FIG. 2, a cylinder 31 is formed in the cylinder block 12 of the internal combustion engine 10, and a piston 32 is inserted into the cylinder 31 so as to be movable along the axial direction of the cylinder 31. A combustion chamber 33 is formed by the cylinder head 11, the cylinder 31, and the piston 32. That is, the combustion chamber 33 is formed by a space surrounded by the combustion chamber wall 34 at the top, the piston 32 at the bottom, and the cylinder 31 at the side. The combustion chamber wall 34 is a partition wall between the combustion chamber 33 and the water jacket 4 formed in the cylinder head 2 and the cylinder block 3.

  As shown in FIG. 1, a cooling water passage for circulating cooling water inside the internal combustion engine (cooling water in the water jacket 13) to the outside of the internal combustion engine 10 is connected to the internal combustion engine 10. The cooling water passage is provided with an electric pump 28 that circulates the cooling water through the water jacket 13 of the internal combustion engine 10 and can change the flow rate of the cooling water. In addition, the cooling water passage includes a first circulation passage 21 that circulates through the radiator 24, a second circulation passage 22 that circulates through the heater core 25, and a third circulation passage 23 that circulates through the bypass passage 26. A part of each circulation passage has a portion shared with other circulation passages. For example, the water jacket 13 is included in all circulation passages. A cooling water temperature sensor 101 that outputs a signal corresponding to the temperature of the cooling water is attached in the vicinity of the outlet from the internal combustion engine 10 (the water jacket 13a of the cylinder head 11) in each circulation passage. The configuration of each circulation passage and the devices arranged in each circulation passage are examples, and can be changed as appropriate.

  A radiator 24, a thermostat 27, an electric pump 28, a water jacket 13, and the like are disposed in the first circulation passage 21. The thermostat 27 causes the cooling water to flow through the first circulation passage 21 when the cooling water temperature is high, and allows the cooling water to flow through the third circulation passage 23 when the cooling water temperature is low. In the first circulation passage 21, the cooling water discharged from the electric pump 28 circulates in the order of the water jacket 13, the radiator 24, and the thermostat 27. In this embodiment, the cooling water discharged from the electric pump 28 is supplied to the water jacket 13 b of the cylinder block 12, and then the cooling water flowing out of the water jacket 13 b is supplied to the water jacket 13 a of the cylinder head 11. It is like that. Alternatively, the water jacket 13a of the cylinder head 11 and the water jacket 13b of the cylinder block 12 may be arranged in parallel so that the cooling water is individually supplied to the water jackets 13a and 13b.

  The second circulation passage 22 includes a heater core 25, an electric pump 28, and a water jacket 13. In the second circulation passage 22, the cooling water discharged from the electric pump 28 circulates in the order of the water jacket 13 and the heater core 25.

  The third circulation passage 23 includes a bypass passage 26, a thermostat 27, an electric pump 28, and a water jacket 13. The bypass passage 26 is a passage that bypasses the radiator 24. In the third circulation passage 23, the cooling water discharged from the electric pump 28 circulates in the order of the water jacket 13, the bypass passage 26, and the thermostat 27.

  The internal combustion engine 10 configured as described above is provided with an ECU 100 as an electronic control unit for controlling the internal combustion engine 10. The ECU 100 is a unit that controls the operation state of the internal combustion engine 10 according to the operation conditions of the internal combustion engine 10 and the request of the driver. The ECU 100 includes the coolant temperature sensor 101, an accelerator opening sensor 102 that outputs a signal corresponding to the accelerator opening, that is, the engine load, a crank position sensor 103 that outputs a signal corresponding to the rotational speed of the internal combustion engine 10, and an internal combustion engine. An air flow meter 104 that outputs a signal corresponding to the intake air amount of the engine 10 and an outside air temperature sensor 105 that outputs a signal corresponding to the outside air temperature (outside air temperature) are connected via an electrical wiring. It is input to the ECU 100.

  In addition, the electric pump 28 is connected to the ECU 100 via electric wiring, and the ECU 100 controls the driving (operation) of the electric pump 28. By adjusting the electric power supplied to the electric pump 28 by the EUC 100, the operation of the electric pump 28 is controlled, and the discharge amount of the cooling water, that is, the flow rate of the cooling water can be adjusted. Further, the control of the electric pump 28 is performed independently of the control of the internal combustion engine 10. For example, the electric pump 28 can be stopped even during the operation of the internal combustion engine 10.

  According to Japanese Patent No. 2666366, the amount of change in the temperature of the combustion chamber wall 34 (combustion chamber wall temperature) of the internal combustion engine 10 is obtained by the following model equation.

CcΔTc = Hc (Tg−Tc) −Hw (Tc−Tw) (1)

In this equation (1), Cc is the heat capacity of the combustion chamber wall 34, ΔTc is the amount of change in the combustion chamber wall temperature, Hc is the heat transfer coefficient from the combustion gas to the combustion chamber wall 34 (combustion gas side heat transfer coefficient), Tg Is the temperature of the combustion gas in the combustion chamber 33, Tc is the combustion chamber wall temperature, Hw is the heat transfer coefficient (cooling water side heat transfer coefficient) from the combustion chamber wall 34 to the cooling water, and Tw is the cooling water temperature. Here, the cooling water temperature Tw is a detection value detected by the cooling water temperature sensor 101 when the electric pump 28 is operated. Further, the heat capacity Cc, the combustion gas side heat transfer coefficient Hc, and the cooling water side heat transfer coefficient Hw of the combustion chamber wall 34 are values obtained in advance by experiments. Further, the cooling water side heat transfer coefficient Hw is a constant value for simplification, and the combustion gas temperature Tg is substantially constant at around 200 ° C. The heat capacity Cc of the combustion chamber wall 34 may be the heat capacity of the internal combustion engine 10.

  When the above equation (1) is transformed and discretized with the sample time as t, the following equation (2) is obtained.

この式（２）をＥＣＵ１００に格納しておき、式（２）の各項に値（冷却水温度Ｔｗなどの値）を代入することによって、燃焼室壁温度Ｔｃを求めることができる。冷却水温度Ｔｗとしては、冷却水温度センサ１０１から得られる検出値が用いられる。

The equation (2) is stored in the ECU 100, and the combustion chamber wall temperature Tc can be obtained by substituting a value (a value such as the cooling water temperature Tw) into each term of the equation (2). As the cooling water temperature Tw, a detection value obtained from the cooling water temperature sensor 101 is used.

  On the other hand, in this embodiment, when the electric pump 28 is stopped, the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine 10 (the cooling water temperature of the water jacket 13) are estimated simultaneously. In this case, the model formula is as follows.

CcΔTc = Hc (Tg−Tc) −Hw (Tc−Tw2) (3)
CwΔTw2 = Hw (Tc−Tw2) −Ha (Tw2−Ta) (4)
In Expressions (3) and (4), Tw2 is the cooling water temperature when the electric pump 28 is stopped, Cw is the heat capacity of the cooling water in the water jacket 13, and Ha is the heat transfer rate from the cooling water in the water jacket 13 to the outside. , Ta is the external temperature. Here, the heat capacities Cc and Cw, the heat transfer coefficients Hc, Hw, and Ha are values obtained in advance by experiments. The combustion gas temperature Tg in the combustion chamber 33 is a value estimated based on the operating state (engine speed and engine load) of the internal combustion engine 10, and is obtained in advance through experiments or the like and further mapped to the ECU 100. Remember me. Further, when the electric pump 28 is stopped, the amount of cooling water in the water jacket 13 is constant, so the heat capacity Cw is set to a constant value.

  In the above equation (3), the amount of heat transfer from the combustion gas to the combustion chamber wall 34 when the electric pump 28 is stopped is represented by Hc (Tg−Tc), and the amount of heat transfer from the combustion chamber wall 34 to the cooling water. Is represented by Hw (Tc−Tw2), and the heat balance of the combustion chamber wall 34 is represented by Hc (Tg−Tc) −Hw (Tc−Tw2). The heat balance of the combustion chamber wall 34 is the difference between the amount of heat received by the combustion chamber wall 34 from the combustion gas and the amount of heat given from the combustion chamber wall 34 to the cooling water. Then, the amount of change ΔTc in the combustion chamber wall temperature when the electric pump 28 is stopped can be obtained from the heat balance of the combustion chamber wall 34 and the heat capacity Cc.

  In the above equation (4), the amount of heat transfer from the combustion chamber wall 34 to the cooling water of the water jacket 13 when the electric pump 28 is stopped is expressed as Hw (Tc−Tw2), and from the cooling water of the water jacket 13 to the outside The heat transfer amount to the water jacket 13 is represented by Ha (Tw2-Ta), and the heat balance of the cooling water in the water jacket 13 is represented by Hw (Tc-Tw2) -Ha (Tw2-Ta). The heat balance of the cooling water of the water jacket 13 is the difference between the amount of heat received by the cooling water of the water jacket 13 from the combustion chamber wall 34 and the amount of heat released from the cooling water of the water jacket 13 to the outside. And the variation | change_quantity (DELTA) Tw2 of the cooling water temperature of the water jacket 13 at the time of the stop of the electric pump 28 can be obtained from the heat balance of the cooling water of the water jacket 13, and the heat capacity Cw.

  In this embodiment, the amount of heat released from the cooling water of the water jacket 13 to the outside is the amount of heat Q1 released from the cooling water of the water jacket 13 to the outside air 200 (see FIG. 3). Specifically, the amount of heat is released from the cooling water of the water jacket 13 to the outside air 200 through the outer wall portion 35 outside the water jacket 13. In the above formula (4), the temperature (outside air temperature) of the outside air 200 is used as the external temperature Ta, and the heat transfer rate from the cooling water of the water jacket 13 to the outside air 200 is used as the heat transfer rate Ha. .

  When the electric pump 28 is stopped, the above equations (3) and (4) influence each other, so that a differential equation of two-dimensional variables is obtained. That is, the change amount ΔTc of the combustion chamber wall temperature changes according to the cooling water temperature Tw2, the change amount ΔTw2 of the cooling water temperature changes according to the combustion chamber wall temperature Tc, and the combustion chamber wall temperature Tc and the cooling water temperature Tw2 are , They influence each other. For this reason, said Formula (3) and Formula (4) can be solved as a differential equation of the two-dimensional variable which makes the combustion chamber wall temperature Tc and the cooling water temperature Tw2 a variable. By solving this differential equation, the combustion chamber wall temperature Tc and the cooling water temperature Tw2 can be obtained simultaneously. Here, first, the above equations (3) and (4) are modified as follows.

この式（５）を変形するために、式（５）の各項を次のように置き換える。

In order to transform this equation (5), each term of equation (5) is replaced as follows.

上記のような置き換えにより、式（５）は、次の式（６）のように表される。

By the above replacement, the equation (5) is expressed as the following equation (6).

CΔT = A · T + B · u (6)
When this equation (6) is further modified, the following equation (7) is obtained.

ΔT = C ⁻¹ · A · T + C ⁻¹ · B · u (7)
When this equation (7) is discretized with the sample time as t, the following equation (8) is obtained.

この式（８）をＥＣＵ１００に格納しておき、式（８）の各項に値（燃焼ガス温度Ｔｇ、外部温度Ｔａなどの値）を代入することによって、燃焼室壁温度Ｔｃおよびウォータジャケット１３の冷却水温度Ｔｗ２が同時に得られる。燃焼ガス温度Ｔｇとしては、内燃機関１０の運転状態から推定される推定値が用いられ、また、外部温度Ｔａとしては、外気温センサ１０５によって検出される検出値が用いられる。

The equation (8) is stored in the ECU 100, and values (values such as the combustion gas temperature Tg and the external temperature Ta) are substituted into the terms of the equation (8), whereby the combustion chamber wall temperature Tc and the water jacket 13 are substituted. The cooling water temperature Tw2 is obtained at the same time. An estimated value estimated from the operating state of the internal combustion engine 10 is used as the combustion gas temperature Tg, and a detected value detected by the outside air temperature sensor 105 is used as the external temperature Ta.

  As described above, according to this embodiment, the combustion chamber wall temperature Tc and the coolant temperature Tw2 of the water jacket 13 when the electric pump 28 is stopped can be estimated simultaneously. The ECU 100 can control the internal combustion engine 10 based on the combustion chamber wall temperature Tc and the coolant temperature Tw2 obtained in this way.

  In this embodiment, the above equation (4) is an equation that takes into consideration the heat released from the cooling water of the water jacket 13 to the outside air 200, that is, the surface heat radiation from the internal combustion engine 10. For this reason, the combustion chamber wall temperature Tc and the cooling water temperature Tw2 of the water jacket 13 obtained from the above formulas (3) and (4) are values in consideration of the surface heat radiation of the internal combustion engine 10. Therefore, the estimation error of the combustion chamber wall temperature Tc and the cooling water temperature Tw2 can be made smaller than in the conventional example, and the combustion chamber wall temperature Tc and the cooling water temperature Tw2 can be obtained more accurately.

  Here, when the internal combustion engine 10 is warmed up, the electric pump 28 is stopped and the circulation of the cooling water to the water jacket 13 of the internal combustion engine 10 is stopped, so that the internal combustion engine 10 can be warmed up early. Whether or not the internal combustion engine 10 is warming up is determined based on the coolant temperature Tw2 of the water jacket 13 of the internal combustion engine 10, and the water obtained from the above equations (3) and (4) is used for this determination. The cooling water temperature Tw2 of the jacket 13 can be used. Specifically, when the cooling water temperature Tw2 of the water jacket 13 obtained from the above equations (3) and (4) is lower than a predetermined warm-up completion temperature, the internal combustion engine 10 is warming up. If it is equal to or higher than the warm-up completion temperature, it is determined that the warm-up of the internal combustion engine 10 has been completed.

  Further, when the internal combustion engine 10 is warmed up, when the stop control of the electric pump 28, in other words, the cooling water circulation stop control to the water jacket 13 of the internal combustion engine 10, the problem in the case of the conventional example can be solved. . That is, in an environment where the outside air temperature is low, it can be avoided that the cooling water temperature Tw2 of the water jacket 13 estimated from the above equations (3) and (4) is estimated to be higher than the actual cooling water temperature. It is possible to prevent the cooling water circulation from being stopped early. Thereby, it can avoid that warm-up becomes inadequate in the internal combustion engine 10, and the deterioration of a fuel consumption can be suppressed.

  Conversely, in an environment where the outside air temperature is high, it is possible to avoid that the cooling water temperature Tw2 of the water jacket 13 estimated from the above equations (3) and (4) is estimated to be lower than the actual cooling water temperature. In addition, prolonged suspension of cooling water can be avoided. Thereby, the local boiling of cooling water, overheating, thermal degradation, etc. can be suppressed in the internal combustion engine 10, and the fall of reliability can be avoided.

  Here, by changing the estimation model of the combustion chamber wall temperature when the electric pump 28 is activated and stopped, the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine can be obtained more accurately. Specifically, as shown in the flowchart of FIG. 4, when the electric pump 28 is operated, the combustion chamber wall temperature Tc is estimated by the above equation (2), while when the electric pump 28 is stopped, the above equation (8). ) Simultaneously estimate the combustion chamber wall temperature Tc and the cooling water temperature Tw2.

  The flowchart of FIG. 4 is repeatedly executed every predetermined time. In step ST11, the ECU 100 determines whether or not the electric pump 28 is operating. If an affirmative determination is made in step ST11, the process proceeds to step ST12. On the other hand, if a negative determination is made, the process proceeds to step ST13.

  In step ST12, the EUC 100 estimates the combustion chamber wall temperature Tc from the above equation (2). When the electric pump 28 is operated, the cooling water circulates in the first circulation passage 21 or the second circulation passage 22, so that the cooling water temperature obtained by the cooling water temperature sensor 101 and the cooling water temperature of the water jacket 13 are There is almost no difference. For this reason, the cooling water temperature of the water jacket 13 can be obtained more accurately by setting the value obtained by the cooling water temperature sensor 101 to the cooling water temperature Tw. Thus, since it is not necessary to estimate the coolant temperature Tw when the electric pump 28 is operated, the processing can be simplified. The combustion chamber wall temperature Tc can be obtained more accurately from the cooling water temperature detected by the cooling water temperature sensor 101 based on the above equation (2).

  On the other hand, in step ST13, the ECU 100 simultaneously estimates the combustion chamber wall temperature Tc and the cooling water temperature Tw2 from the above equation (8). When the electric pump 28 is stopped, the difference between the cooling water temperature obtained by the cooling water temperature sensor 101 and the cooling water temperature of the water jacket 13 becomes large. Therefore, the combustion chamber wall temperature Tc and the water jacket are calculated by the above equation (8). 13 cooling water temperatures Tw2 are obtained simultaneously. In this way, it is possible to improve the estimation accuracy of the combustion chamber wall temperature Tc and the cooling water temperature Tw2 when the electric pump 28 is stopped and when the internal combustion engine 10 is in operation.

-Other embodiments-
In the above embodiment, the value detected by the outside air temperature sensor 105 is used as the external temperature Ta. However, as the external temperature Ta, the coolant temperature at the start of the internal combustion engine 10 or the intake air temperature at the start of the internal combustion engine 10 is used. May be used. The cooling water temperature at the start of the internal combustion engine 10 is detected by the cooling water temperature sensor 101, and the intake air temperature at the start of the internal combustion engine 10 is an intake air temperature sensor (not shown) provided in the intake passage of the internal combustion engine 10. ) Is detected. In this way, the outside air temperature sensor as described above can be used by substituting the value detected by the cooling water temperature sensor 101 or the intake air temperature sensor used for controlling the operating state of the internal combustion engine 10 as the external temperature Ta. There is no need to provide 105 separately.

  In the above embodiment, the amount of heat released from the cooling water of the water jacket 13 to the outside is the amount of heat Q1 released to the outside air 200 (see FIG. 3). However, the present invention is not limited to this, and the amount of heat released from the cooling water of the water jacket 13 to the outside may be the amount of heat Q2 released to the peripheral component 300 arranged around the internal combustion engine 10 (see FIG. 5). In this case, in the above equation (4), the temperature of the peripheral component 300 is used as the external temperature Ta, and the heat transfer rate from the cooling water of the water jacket 13 to the peripheral component 300 is used as the heat transfer rate Ha. Also in this case, as the external temperature Ta (the temperature of the peripheral component 300), it is possible to substitute the coolant temperature at the start of the internal combustion engine 10 or the intake air temperature at the start of the internal combustion engine 10. The amount of heat released from the cooling water of the water jacket 13 to the outside is both the amount of heat Q1 released to the outside air 200 and the amount of heat Q2 released to the peripheral component 300 arranged around the internal combustion engine 10. It is also possible.

  The present invention relates to cooling of an internal combustion engine including a pump capable of circulating cooling water inside the internal combustion engine and changing the flow rate of the cooling water, and a cooling water passage for circulating cooling water inside the internal combustion engine to the outside of the internal combustion engine. It can be used to control the system.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 13 Water jacket 28 Electric pump 33 Combustion chamber 34 Combustion chamber wall 100 ECU
101 Coolant temperature sensor 102 Accelerator opening sensor 103 Crank position sensor 104 Air flow meter

Claims (7)

  The amount of heat received by the combustion chamber wall from the combustion gas and the amount of heat given to the cooling water from the combustion chamber wall and the amount of change in the combustion chamber wall temperature calculated from the heat capacity of the combustion chamber wall, and the cooling water received from the combustion chamber wall Simultaneously estimate the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine based on the difference between the amount of heat and the amount of heat released from the cooling water to the outside and the amount of change in the cooling water temperature calculated from the heat capacity of the cooling water An internal combustion engine control apparatus comprising an estimation means. The control apparatus for an internal combustion engine according to claim 1,
The amount of heat released from the cooling water to the outside is the product of the difference between the cooling water temperature and the external temperature and the heat transfer coefficient, and the external temperature is the cooling water temperature at the start of the internal combustion engine, Or the control apparatus of the internal combustion engine characterized by using the intake air temperature at the time of starting of the internal combustion engine. The control apparatus for an internal combustion engine according to claim 1 or 2,
The control apparatus for an internal combustion engine, characterized in that the amount of heat released from the cooling water to the outside is the amount of heat released to the outside air. The control apparatus for an internal combustion engine according to claim 1 or 2,
The control device for an internal combustion engine, characterized in that the amount of heat released from the cooling water to the outside is a heat amount released to peripheral components arranged around the internal combustion engine. In the control device for an internal combustion engine according to any one of claims 1 to 4,
A control device for an internal combustion engine, wherein the circulation of cooling water into the internal combustion engine is stopped when the internal combustion engine is warmed up. In the control device for an internal combustion engine according to any one of claims 1 to 5,
A pump capable of circulating the cooling water inside the internal combustion engine and changing the flow rate of the cooling water;
The control apparatus for an internal combustion engine, wherein the estimation means estimates the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine when the pump is stopped. The control apparatus for an internal combustion engine according to claim 6,
A cooling water temperature detecting means for detecting a cooling water temperature flowing out from the internal combustion engine;
During the operation of the pump, the combustion chamber wall temperature and the cooling water temperature inside the internal combustion engine are not estimated by the estimating means, and the combustion chamber wall temperature is determined based on the cooling water temperature detected by the cooling water temperature detecting means. A control device for an internal combustion engine characterized by estimating.

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