JP2007132313A - Cooling controller of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a cooling controller of conventional internal combustion engines wherein the supplied amount of cooling water to a cooling part may not be most suitable depending on the operating conditions of the engine since the cooling of the cooling part is not controlled according to the combustion temperature of air-fuel mixture and the temperature of exhaust gases. <P>SOLUTION: This cooling controller of an internal combustion engine comprises a plurality of cooling parts 12, 13, 15 to which a cooling refrigerant is supplied and a plurality of cooling medium supply passages 20c, 20p, 20t guiding the cooling medium to the cooling parts 12, 13, 15. The cooling controller further comprises flow control valves 22c, 22p, 22t capable of changing the supplied rate of the cooling medium to the cooling parts 12, 13, 15 and a control unit controlling the operation of the flow control valves 22c, 22p, 22t so that the supplied ratio of the cooling medium to the cooling medium supply passages 20c, 20p, 20t can be changed according to the operating conditions of the engine. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cooling control device for an internal combustion engine having a plurality of independent cooling paths.

  In a spark ignition internal combustion engine or a compression ignition internal combustion engine, a circulation passage for a cooling medium (hereinafter referred to as cooling water for convenience) is formed in a portion requiring cooling, and the cooling water is allowed to flow there. Such a cooling device is incorporated. In addition, when cooling water is supplied to the engine cooling section with this cooling device, the cylinder head is not damaged or the cooling water is boiled in the operating region where the heat loss due to the cooling water is greatest during high load operation of the engine. In addition, the flow rate ratio of the cooling water is set. Conventionally, the flow rate of the cooling water is set to be almost constant regardless of the operating state of the engine.

  On the other hand, in such an internal combustion engine, a three-way catalyst and an oxidation catalyst are also incorporated in the middle of the exhaust passage so that harmful components contained in the exhaust gas are not discharged outside the engine. In this case, since it is necessary to keep the catalyst in an active state, when the engine is warmed up or under a low load, the exhaust medium is not circulated without circulating the cooling medium to the cooling section that may lower the temperature of the exhaust gas. It is effective to guide the catalyst in a high temperature state and thereby keep the catalyst at a high temperature. Such a technique is disclosed in Patent Document 1.

  In Patent Document 1, a first cooling medium passage that surrounds an exhaust passage and a collection portion of exhaust passages formed in a cylinder head, and a second cooling medium passage that surrounds an exhaust port are formed. The supply amount of the cooling medium is controlled independently for each of the second cooling medium passages. More specifically, when the engine is under a low load, the cooling medium is not circulated through the first cooling medium passage, but is guided to the catalyst in a state in which cooling of the exhaust gas is suppressed, thereby activating the catalyst. Promoting.

JP-A-60-85215

  It is known that the combustion temperature of the air-fuel mixture and the temperature of the exhaust gas vary depending on the air-fuel ratio in the combustion chamber, that is, the in-cylinder A / F. The cooling of the cooling unit is not controlled according to the exhaust gas temperature. For this reason, the supply amount of the cooling water to the cooling unit may not be optimal depending on the operating state of the engine.

  For example, in order to activate the catalyst in the idle operation state, it is necessary to raise the temperature of the exhaust gas. However, the exhaust gas is cooled more than necessary by the cooling water flowing around the exhaust port. In the operating state, the temperature of the catalyst is difficult to rise.

  Similar problems also occur in a lean burn operation state in which fuel is supplied to the intake air amount less than the stoichiometric air-fuel ratio and burned. In other words, in lean burn operation where the temperature of the exhaust gas is likely to decrease, fuel efficiency can be improved, but the temperature of the exhaust gas decreases due to the cooling water flowing around the exhaust port, and the temperature of the catalyst decreases. Activation may be insufficient.

  In addition, in the high-load high-speed operation region of the engine, cooling water is flowed around the exhaust port to lower the exhaust temperature to improve fuel efficiency, while cooling water is flowed around the combustion chamber to cause knocking. It is basically difficult to contemplate simultaneously improving the engine output by suppressing it.

  Further, the cylinder group constituting the engine is divided into two groups. One cylinder group is supplied with fuel more than the stoichiometric air-fuel ratio, and the other group is supplied with fuel less than the stoichiometric air-fuel ratio. In so-called bank control, in which exhaust gas that has finally reached the stoichiometric air-fuel ratio is led to the catalyst by alternately switching this, the exhaust gas on the lean side having a low temperature is cooled more than necessary by the cooling water flowing around the exhaust port. Is done. As a result, the temperature of the catalyst is raised and the efficiency of the bank control for desulfurizing the sulfur component adhering thereto is lowered.

  An object of the present invention is to provide a cooling control device for an internal combustion engine that can perform optimum cooling in accordance with the operating state of the engine and thereby can further improve fuel consumption and output.

  A first aspect of the present invention is a cooling control device for an internal combustion engine having a plurality of cooling units to which a cooling medium is respectively supplied and a plurality of cooling medium supply passages that respectively guide the cooling medium to the plurality of cooling units. Adjusting means that can change the supply ratio of the cooling medium to the plurality of cooling sections, respectively, and the adjustment so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed according to the operating state of the engine. And a control means for controlling the operation of the means.

  In the present invention, the control means controls the operation of the adjusting means in accordance with the operating state of the engine, and the supply ratio of the cooling medium to the plurality of cooling units is changed via each cooling medium supply passage.

  In the cooling control apparatus for an internal combustion engine according to the first aspect of the present invention, the cooling unit may include at least one of an exhaust port and a supercharger.

  The second aspect of the present invention includes a plurality of cooling sections to which a cooling medium is respectively supplied, and a plurality of cooling medium supply passages that respectively guide the cooling medium to the plurality of cooling sections, and the engine at a stoichiometric air-fuel ratio. A cooling control unit for an internal combustion engine that can be switched between a stoichiometric operation state in which the engine is operated and a lean burn operation state in which the engine is operated by setting the fuel to be less than the stoichiometric air-fuel ratio. Adjusting means capable of changing the supply ratio of the medium, and control means for controlling the operation of the adjusting means so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed according to the operating state of the engine; The cooling unit includes at least one of an exhaust port and a supercharger, and the control means includes at least one of the exhaust port and the supercharger in a lean burn operation state. The supply amount of the cooling medium with respect is characterized in that for controlling the operation of the adjusting means to be less than the supply amount of the cooling medium in a stoichiometric operating condition.

  In the present invention, the control means controls the operation of the adjusting means in accordance with the operating state of the engine, and the supply ratio of the cooling medium to the plurality of cooling units is changed via each cooling medium supply passage. Particularly in the lean burn operation state, the control means operates the adjusting means so that the supply amount of the cooling medium to at least one of the exhaust port and the supercharger is smaller than the supply amount of the cooling medium in the stoichiometric operation state. To control. As a result, the temperature of the exhaust gas in the lean burn operation state rises higher than the temperature of the exhaust gas in the stoichiometric operation state.

  In the cooling control apparatus for an internal combustion engine according to the second aspect of the present invention, the control means provides cooling supplied to at least one of the exhaust port and the supercharger as the temperature of the exhaust gas or the catalyst in the lean burn operation state increases. The supply ratio of the medium may be increased.

  In the cooling control apparatus for an internal combustion engine according to the first or second aspect of the present invention, the cooling unit may include a combustion chamber of the engine.

  According to a third aspect of the present invention, a first cylinder group, a second cylinder group that can be supplied with less fuel than the stoichiometric air-fuel ratio, a plurality of cooling units each supplied with a cooling medium, and a plurality of these A cooling control device for an internal combustion engine having a plurality of cooling medium supply passages that respectively guide the cooling medium to the cooling section of the engine, and an adjustment unit that can respectively change a supply ratio of the cooling medium to the plurality of cooling sections; Control means for controlling the operation of the adjusting means so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed according to the operating state, and the plurality of cooling sections are in the first cylinder group Combustion chamber group and combustion chamber group of the second cylinder group, and the control means supplies a cooling medium supply rate for cooling the combustion chamber group of the second cylinder group to the first cylinder. Guru Is characterized in that for controlling the operation of the adjusting means to be less than the feed rate of the cooling medium for cooling the combustion chamber group flop.

  In the present invention, the control means controls the operation of the adjusting means in accordance with the operating state of the engine, and the supply ratio of the cooling medium to the plurality of cooling units is changed via each cooling medium supply passage. In particular, the control means makes the supply ratio of the cooling medium for cooling the combustion chamber group of the second cylinder group smaller than the supply ratio of the cooling medium for cooling the combustion chamber group of the first cylinder group. And controlling the operation of the adjusting means.

  In the cooling control apparatus for an internal combustion engine according to the third aspect of the present invention, when fuel less than the stoichiometric air-fuel ratio is supplied to the second cylinder group, the first cylinder group has more fuel than the stoichiometric air-fuel ratio. Can be supplied.

  The cooling control apparatus for an internal combustion engine according to the first to third aspects of the present invention may further include a bypass passage that allows the cooling medium to pass therethrough without being guided to the cooling unit.

  The operating state of the engine may include at least one of the temperature of the cooling medium, the temperature of the exhaust gas exhausted from the engine, the temperature of the catalyst for purifying the exhaust gas, or the air-fuel ratio of the combustion gas. . Alternatively, the rotational speed and output torque of the engine can be included.

  The control means may control the operation of the adjusting means so that the cooling medium does not boil.

  According to the cooling control apparatus for an internal combustion engine of the present invention having a plurality of cooling units to which cooling medium is respectively supplied and a plurality of cooling medium supply passages for guiding the cooling medium to the plurality of cooling units, respectively, Adjusting means capable of respectively changing the supply ratio of the cooling medium, and control means for controlling the operation of the adjusting means so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed according to the operating state of the engine. Thus, the cooling state of each cooling unit can be optimally controlled according to the operating state of the engine.

  When the cooling unit includes at least one of an exhaust port and a supercharger, the exhaust gas can be adjusted to an appropriate temperature according to the operating state of the engine, and thereby, for example, the catalyst can always work efficiently. It becomes possible.

  A stoichiometric operation state in which an engine is operated at a stoichiometric air-fuel ratio, and a plurality of cooling sections to which a cooling medium is supplied, and a plurality of cooling medium supply passages that respectively guide the cooling medium to the plurality of cooling sections; According to the cooling control unit for an internal combustion engine of the present invention that can be switched to a lean burn operation state in which the engine is operated with the fuel set to be less than the air-fuel ratio, the supply ratio of the cooling medium to the plurality of cooling units is changed respectively. Adjustment means to obtain, and control means for controlling the operation of the adjustment means so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed according to the operating state of the engine, The control means includes at least one of the superchargers, and the control means determines whether the supply amount of the cooling medium to at least one of the exhaust port and the supercharger in the lean burn operation state is a stroke. Since the operation of the adjusting means is controlled so as to be less than the supply amount of the cooling medium in the Kio operation state, the temperature reduction of the exhaust gas in the lean burn operation state is suppressed, so that the inactivation due to the catalyst temperature decrease is obviated. Can be prevented. In particular, when the control means increases the supply rate of the cooling medium supplied to at least one of the exhaust port and the supercharger as the temperature of the exhaust gas or the catalyst in the lean burn operation state increases, the temperature of the catalyst Can be maintained at an optimum temperature.

  When the cooling unit includes a combustion chamber of the engine, the combustion chamber can be maintained at an optimum temperature according to the operating state of the engine, and for example, occurrence of knocking can be suppressed.

  A first cylinder group, a second cylinder group that can be supplied with less fuel than the stoichiometric air-fuel ratio, a plurality of cooling units each supplied with a cooling medium, and a cooling medium guided to the plurality of cooling units, respectively. According to the cooling control apparatus for an internal combustion engine of the present invention having a plurality of cooling medium supply passages, the adjusting means capable of respectively changing the supply ratio of the cooling medium to the plurality of cooling units, and the plurality of cooling depending on the operating state of the engine Control means for controlling the operation of the adjusting means so that the supply ratio of the cooling medium to the medium supply passage is changed, and the plurality of cooling sections are provided in the combustion chamber group of the first cylinder group and the second cylinder group. And the control means is configured so that a supply rate of the cooling medium for cooling the combustion chamber group of the second cylinder group is equal to a supply rate of the cooling medium for cooling the combustion chamber group of the first cylinder group. The operation of the adjusting means is controlled so that the number of combustion chambers is reduced, so that when the combustion states are different between the first cylinder group and the second cylinder group, the respective cooling chamber groups can be optimally cooled. it can.

  When less fuel than the stoichiometric air-fuel ratio is supplied to the second cylinder group and more fuel than the stoichiometric air-fuel ratio is supplied to the first cylinder group, the exhaust from the second cylinder group in the lean burn state A decrease in the temperature of the gas can be suppressed, thereby preventing a decrease in the temperature of the catalyst.

  In the case of further including a bypass passage that allows the cooling medium to pass through without being guided to the cooling unit, the temperature of the cooling unit can be quickly increased, and thereby, for example, activation of the catalyst can be promoted. In addition, fuel consumption can be improved as the load on the pump that pumps the cooling medium is reduced.

  When the operating state of the engine includes at least one of the temperature of the cooling medium, the temperature of the exhaust gas exhausted from the engine, and the temperature of the catalyst for purifying the exhaust gas, each cooling unit according to these temperatures The cooling of the catalyst can be adjusted optimally, so that, for example, the catalyst can always work efficiently.

  When the operating state of the engine includes the air-fuel ratio of the combustion gas, the cooling for the individual cooling units can be optimally adjusted according to the air-fuel ratio.

  When the operating state of the engine includes the rotational speed and output torque of the engine, the cooling for the individual cooling units can be optimally adjusted according to the rotational speed and output torque of the engine.

  When the control means controls the operation of the adjusting means to avoid boiling of the cooling medium, it is possible to reliably prevent the cooling efficiency from being lowered.

  An embodiment in which a cooling control device for an internal combustion engine according to the present invention is applied to a vehicle equipped with a spark ignition internal combustion engine will be described in detail with reference to FIGS. However, the present invention is not limited to such an embodiment, and may be modified or modified in any way encompassed by the concept of the present invention described in the claims, and thus other modifications belonging to the spirit of the present invention. Of course, it can be applied to any technique.

  The concept of this embodiment is shown in FIG. 1, and its control block is shown in FIG. That is, the spark ignition internal combustion engine (hereinafter simply referred to as an engine) in the present embodiment includes a supercharger 12 having a wastegate valve 11 and a fuel injection valve 14 that directly injects fuel into the combustion chamber 13. A direct injection type fuel injection device, and a cooling control device for cooling the periphery of the combustion chamber 13 of the engine, the periphery of the exhaust port 15, and the bearing portion of the supercharger 12 are provided.

  The cooling control device according to the present embodiment passes through an independent cooling unit for cooling the combustion chamber 13, the exhaust port 15, and the supercharger 12 by the cooling water pump 17 from the radiator 16 and the heater core 18 for heating the vehicle interior. The cooling water circulation path 19 returns to the radiator 16 again. Between the cooling water pump 17 and the heater core 18, a combustion chamber cooling water passage 20 c that mainly cools the periphery of the combustion chamber 13, an exhaust port cooling water passage 20 p that mainly cools the periphery of the exhaust port 15, and mainly supercharging. A supercharger cooling water passage 20t for cooling the bearing portion of the machine 12 and a bypass passage 21 are incorporated in parallel. The combustion chamber cooling water passage 20c guides cooling water around the combustion chamber 13, the exhaust port cooling water passage 20p guides cooling water around the exhaust port 15, and the supercharger cooling water passage 20t is a bearing of the supercharger 12. Cooling water is guided around the part, and the bypass passage 21 is for directly passing the cooling water pumped from the cooling water pump 17 to the heater core 18 side without guiding it to each of the cooling parts described above.

  As the adjusting means of the present invention, the cooling water passages 20c, 20p, 20t (hereinafter may be collectively described as 20) and the bypass passage 21 can arbitrarily adjust the flow rate of the cooling water flowing through them. The first to fourth flow control valves 22c, 22p, 22t, 22w (hereinafter, these may be collectively referred to as 22) are interposed. The first to fourth flow rate control valves 22 are controlled by the command from the control unit 23 based on the operating state of the internal combustion engine, that is, the vehicle on which the engine is mounted, respectively. The cooling water passage 20 detects the temperatures Tc, Tp, Tt of the cooling water after cooling the combustion chamber 13, the exhaust port 15 and the supercharger 12, and outputs them to the control unit 23. 3 Water temperature sensors 24c, 24p, 24t are incorporated. Further, the temperature Tw of the cooling water flowing through the cooling water circulation path 19 between the cooling water passage 20 and the downstream portion of the bypass passage 21 and the heater core 18 is detected and output to the control unit 23. A fourth water temperature sensor 24w is incorporated.

  The control unit 23 includes detection signals Tc, Tp, Tt, and Tw from the first to fourth water temperature sensors 24c, 24p, 24t, and 24w (hereinafter sometimes collectively referred to as 24). In addition, it communicates with an air flow sensor 25 for detecting the amount of intake air introduced into the combustion chamber of the engine through an intake passage (not shown), an engine speed sensor 26 for detecting the engine speed Ne per unit time, and the exhaust port 15. Each detection from a catalyst temperature sensor 27 for detecting a catalyst bed temperature Ts (not shown) for purifying exhaust gas discharged to the outside and an exhaust temperature sensor 28 for detecting the temperature Te of the exhaust gas flowing in the exhaust port 15 Signals Ne, Ts, Te are supplied. In the present embodiment, based on the engine cooling speed Ne and the engine load, as shown in FIG. 3, in addition to the cooling mode of “cold start” set in advance based on the detection signal Tw from the fourth water temperature sensor 24w. One of “Idle”, “Lean burn”, “Stoichio”, and “High load high rotation” cooling modes read from the map is selected. Then, based on the detection signals Tc, Tp, Tt, and Tw from the first to fourth water temperature sensors 24, the first to fourth are set so as to achieve warm-up promotion, catalyst activation, and improvement in fuel consumption and output. In addition to the opening degree of the flow rate control valve 22, that is, the cooling water supply ratio X, Y, Z, W to the cooling water passage 20 and the bypass passage 21, the wastegate valve 11 of the supercharger 12 is opened and closed, and the igniter 29 The ignition timing and the fuel injection amount from the fuel injection valve 14 are also controlled via the control unit 23, respectively.

  The engine load described above is read from a map (not shown) stored in advance in the control unit 23 based on the intake air amount detected by the air flow sensor 25 and the engine speed Ne detected by the engine speed sensor 26. I am doing so. Instead, it is read out from a map set in advance based on the opening degree of the throttle valve and the engine speed Ne operated by the driver, or preset based on the pressure in the intake passage and the engine speed Ne. You may make it read from the map.

FIG. 4 shows a cooling mode selection procedure performed by the control unit 23 of the present embodiment. That is, it is first determined in step M11 whether or not the cooling water temperature Tw detected by the fourth water temperature sensor 24w is lower than a preset cold start determination temperature T _JW . Here, when it is determined that the cooling water temperature Tw is lower than the cold start determination temperature T _JW , that is, the “cold start” cooling mode should be selected, the process proceeds to step M12 to perform the cold start. Determine whether the flag is set. At first, since the cold start flag is not set, the process proceeds to step M13 to set the cold start flag, and then initial setting for cold start is performed in step M14. Control is performed in the “cold start” cooling mode.

  If it is determined in step M12 that the cold start flag is set, the process proceeds to step M15 and control in the “cold start” cooling mode is continued.

  In the initial setting for cold start performed in step M14, the cooling water supply ratios X, Y, Z, and W to the cooling water passage 20 and the bypass passage 21 are set to 0, 0, 0, and 100%, respectively. It is to be.

  The “cold start” cooling mode in step M15 is a mode in which the activation of the catalyst is promoted while preventing the cooling water from boiling during the cold start of the engine, and is set to the initial value set in step M14. On the other hand, the supply ratios X, Y, Z, and W of the cooling water to the cooling water passage 20 and the bypass passage 21 are appropriately corrected, and based on this, the control unit 23 adjusts the opening degree of the first to fourth flow control valves 20. To be adjusted.

The procedure of the “cold start” cooling mode in this embodiment is shown in FIG. That is, first, in step S11, it is determined whether or not the detection signal Tc from the first water temperature sensor 24c is higher than a preset reference temperature _TRc . If it is determined that the detection signal Tc is higher than the reference temperature _TRc , that is, it is necessary to cool the combustion chamber 13 to prevent boiling of the cooling water, the routine proceeds to step S12 and the combustion chamber is cooled. The cooling water supply ratio X to the water passage 20c is increased by 1 (%), the process proceeds to step S13, and the cooling water supply ratio W to the bypass passage 21 is calculated. Then, the process returns to step M11.

When it is determined in step S11 that the detection signal Tc from the first water temperature sensor 24c is equal to or lower than the reference temperature _TRc , the process proceeds to step S14 and the detection signal Tp from the second water temperature sensor 24p is set in advance. It is determined whether or not it is higher than the set reference temperature _TRp . Here, if it is determined that the detection signal Tp is higher than the reference temperature _TRp , that is, it is necessary to cool the exhaust port 15 to prevent boiling of the cooling water, the routine proceeds to step S15 to cool the exhaust port. After the cooling water supply ratio Y to the water passage 20p is increased by 1 (%), the process proceeds to step S16, where the catalyst temperature Ts is lower than the preset reference temperature T _Rs , that is, the minimum temperature at which the catalyst is activated. It is determined whether or not.

If it is determined in step S16 that the catalyst temperature Ts is _lower than the reference temperature _TRs , that is, it is necessary to increase the exhaust gas temperature Te to heat the catalyst, the process proceeds to step S17 and the exhaust port cooling water passage is performed. After the cooling water supply ratio Y to 20p is lowered by 1 (%), the process proceeds to step S18 to determine whether or not the cooling water supply ratio Y to the exhaust port cooling water passage 20p is 0 (%) or more. Is done. If it is determined that the cooling water supply ratio Y to the exhaust port cooling water passage 20p is 0 (%) or more, the process proceeds to step S13 to calculate the cooling water supply ratio W to the bypass passage 21. To do. If it is determined in step S18 that the cooling water supply ratio Y to the exhaust port cooling water passage 20p is a negative value, the process proceeds to step S19, where the cooling water to the exhaust port cooling water passage 20p is transferred. After resetting the supply ratio Y to 0 (%), the process proceeds to step S13, and the supply ratio W of the cooling water to the bypass passage 21 is calculated.

On the other hand, if it is determined in step S14 that the detection signal Tp is equal to or lower than the reference temperature T _Rp , the process proceeds to step S20 and the detection signal Tt from the third water temperature sensor 24t is set to a preset reference temperature T. _It is determined whether or not it is higher than _Rt . If it is determined that the detection signal Tt is higher than the reference temperature T _Rt , that is, it is necessary to cool the supercharger 12 to prevent the cooling water from boiling, the routine proceeds to step S21 and supercharging is performed. After raising the cooling water supply ratio Z to the machine cooling water passage 20t by 1 (%), the process proceeds to step S13 to calculate the cooling water supply ratio W to the bypass passage 21. If it is determined in step S20 that the detection signal Tt is equal to or lower than the reference temperature _TRt , that is, it is not necessary to change the cooling water supply ratio Z to the supercharger 12, the process proceeds to step S13. Then, the supply ratio W of the cooling water to the bypass passage 21 is calculated.

In this way, when the cooling water temperature Tw gradually increases and it is determined in step M11 that the cooling water temperature Tw is equal to or higher than the cold start determination temperature T _{JW, the} process proceeds to step M16, and the engine is changed to FIG. It is determined whether or not the vehicle is in the indicated idle operation region. If it is determined that the engine is in the idle operation region, the process proceeds to step M17 to determine whether the idle flag is set. At first, since the idle flag is not set, the process proceeds to step M18 to reset other flags set up to that point and set the idle flag, and then the idle initial setting is performed in step M19. The control in the “idle” cooling mode is performed in step M20.

  If it is determined in step M17 that the idle flag is set, the process proceeds to step M20, and control in the “cold start” cooling mode is performed.

  The initial setting for idling performed in step M19 is to set the cooling water supply ratios X, Y, Z, and W to the cooling water passage 20 and the bypass passage 21 to 0, 0, 0, and 100%, respectively. It is.

  The “idle” cooling mode in step M20 is a mode in which the heater core 18 is heated to such an extent that the heater core 18 can function in addition to maintaining the activation of the catalyst while preventing the cooling water from boiling during the idling operation of the engine. The supply ratios X, Y, Z, and W of the cooling water to the cooling water passage 20 and the bypass passage 21 are appropriately corrected with respect to the initial values set in step M19, and the control unit 23 performs the first correction based on this. -The opening degree of the fourth flow control valve 20 is adjusted.

FIG. 6 shows the procedure of the “idle” cooling mode in this embodiment. That is, the fourth or lower or not than the reference temperature T _RW detection signal Tw is set in advance from the water temperature sensor 24w first at S22 in step is determined. Here, the detection signal Tw is lower than the reference temperature T _RW, that is, if it is determined that it is preferable to raise the temperature of the cooling water through the heater core 18, it proceeds to the combustion chamber cooling water passage 20c to S23 in step After raising the cooling water supply ratio X to 1 (%), the process proceeds to step S24 to calculate the cooling water supply ratio W to the bypass passage 21, and then returns to step M16.

At S22 in step is the fourth temperature detection signal Tw from the sensor 24w is preset reference temperature T _RW or more, if it is determined that that is not necessary to raise the temperature of the cooling water through the heater core 18, In step S25, it is determined whether the detection signal Tp from the second water temperature sensor 24p is higher than the reference temperature _TRp . If it is determined that the detection signal Tp is higher than the reference temperature _TRp , that is, it is necessary to cool the exhaust port 15 to prevent boiling of the cooling water, the routine proceeds to step S26 and the exhaust port cooling is performed. After the cooling water supply ratio Y to the water passage 20p is increased by 1 (%), the process proceeds to step S27, where the catalyst temperature Ts is lower than the preset reference temperature T _Rs , that is, the minimum temperature at which the catalyst is activated. It is determined whether or not.

If it is determined in step S27 that the catalyst temperature Ts is _lower than the reference temperature _TRs , that is, it is necessary to increase the temperature of the exhaust gas to heat the catalyst to prevent boiling of the cooling water, the process proceeds to step S28. Then, the cooling water supply rate Y to the exhaust port cooling water passage 20p is lowered by 1 (%), and then the process proceeds to step S29, where the cooling water supply rate Y to the exhaust port cooling water passage 20p is 0 (%) or more. It is determined whether or not. Here, when it is determined that the supply ratio Y of the cooling water to the exhaust port cooling water passage 20p is 0 (%) or more, there is no particular problem, so the process proceeds to step S24, and the cooling water to the bypass passage 21 is transferred. The supply ratio W is calculated. When it is determined in step S29 that the supply ratio Y of the cooling water to the exhaust port cooling water passage 20p is a negative value, the process proceeds to step S30 and the cooling water to the exhaust port cooling water passage 20p. After resetting the supply ratio Y to 0 (%), the process proceeds to step S24, and the cooling water supply ratio W to the bypass passage 21 is calculated.

On the other hand, if it is determined in step S25 that the detection signal Tp is equal to or lower than the reference temperature _TRp , the process proceeds to step S31 and the detection signal Tt from the third water temperature sensor 24t is higher than the reference temperature _TRt. It is determined whether or not. If it is determined that the detection signal Tt is higher than the reference temperature T _Rt , that is, it is necessary to cool the supercharger 12 to prevent boiling of the cooling water, the routine proceeds to step S32 and supercharging is performed. The cooling water supply ratio Z to the machine cooling water passage 20t is increased by 1 (%), and the process proceeds to step S24 to calculate the cooling water supply ratio W to the bypass passage 21. If it is determined in step S31 that the detection signal Tt is equal to or lower than the reference temperature T _Rt , there is no need to change the cooling state for the supercharger 12, so the process proceeds to step S24 as it is, and the bypass passage The cooling water supply ratio W with respect to 21 is calculated.

In the above embodiment, although the detection signals Tw from the fourth temperature sensor 24w was made to determine whether lower than the reference temperature T _RW at S22 in step, the first temperature sensor in place of the determination routine It may be determined whether the detection signal Tc from 24c is higher than the reference temperature _TRc .

  When it is determined in the previous step M16 that the engine is not in the idle operation region, the process proceeds to step M21, and it is determined whether or not the engine is in the lean burn operation region shown in FIG. If it is determined that the engine is in the lean burn operation region, the process proceeds to step M22 to determine whether the lean burn flag is set. At first, since the lean burn flag is not set, the process proceeds to step M23 to reset other flags set up to that time and set the lean burn flag, and then the lean burn initial setting in step M24. In step M25, control in the “lean burn” cooling mode is performed.

  If it is determined in step M22 that the lean burn flag is set, the process proceeds to step M25, and control in the “lean burn” cooling mode is performed.

  In the initial setting for lean burn performed in step M24, the supply ratios X, Y, Z, and W of the cooling water to the cooling water passage 20 and the bypass passage 21 are set to 100, 0, 0, and 0%, respectively. That is.

  The “lean burn” cooling mode in step M25 is a mode in which the activation of the catalyst is promoted while the cooling water is prevented from boiling during the operation of the engine with the fuel supply amount smaller than the stoichiometric air-fuel ratio. , The supply ratios X, Y, Z, and W of the cooling water to the cooling water passage 20 and the bypass passage 21 are appropriately corrected with respect to the initial values set in the step M24, and the control unit 23 performs the first correction based on this. The opening degree of the 1st-4th flow control valve 20 is adjusted.

FIG. 7 shows the procedure of the “lean burn” cooling mode in the present embodiment. That is, first, in step S33, it is determined whether or not the detection signal Tp from the second water temperature sensor 24p is higher than the reference temperature _TRp . If it is determined that the detection signal Tp is higher than the reference temperature T _Rp , that is, it is necessary to cool the exhaust port 15, the process proceeds to step S34 to supply cooling water to the exhaust port cooling water passage 20p. After the ratio Y is increased by 1 (%), the process proceeds to step S35, where it is determined whether or not the catalyst temperature Ts is lower than a preset reference temperature T _Rs , that is, the minimum temperature at which the catalyst becomes active. The

If it is determined in step S35 that the catalyst temperature Ts is _lower than the reference temperature _TRs , that is, it is necessary to increase the temperature of the exhaust gas to heat the catalyst, the process proceeds to step S36 and the exhaust port cooling water passage 20p. After the cooling water supply ratio Y with respect to is lowered by 1 (%), the routine proceeds to step S37, where it is determined whether or not the cooling water supply ratio Y with respect to the exhaust port cooling water passage 20p is 0 (%) or more. The Here, if it is determined that the supply ratio Y of the cooling water to the exhaust port cooling water passage 20p is 0 (%) or more, there is no particular problem, so the process proceeds to step S38, and the cooling water to the bypass passage 21 is transferred. The supply ratio W is calculated. When it is determined in step S37 that the cooling water supply ratio Y to the exhaust port cooling water passage 20p is a negative value, the process proceeds to step S39 and cooling water to the exhaust port cooling water passage 20p is transferred. After resetting the supply ratio Y to 0 (%), the process proceeds to step S38 to calculate the supply ratio W of the cooling water to the bypass passage 21, and then returns to step M16.

On the other hand, if it is determined in step S33 that the detection signal Tp is equal to or lower than the reference temperature T _Rp , the process proceeds to step S40 and the detection signal Tt from the third water temperature sensor 24t is higher than the reference temperature T _Rt. It is determined whether or not. If it is determined that the detection signal Tt is higher than the reference temperature T _Rt , that is, it is necessary to cool the supercharger 12 to prevent the cooling water from boiling, the routine proceeds to step S41 and supercharging is performed. After raising the cooling water supply ratio Z to the machine cooling water passage 20t by 1 (%), the process proceeds to step S38, and the cooling water supply ratio W to the bypass passage 21 is calculated. If it is determined in step S40 that the detection signal Tt is equal to or lower than the reference temperature T _Rt , that is, it is not necessary to change the cooling state of the supercharger 12, the process proceeds to step S38 and the bypass passage is performed. The cooling water supply ratio W with respect to 21 is calculated.

  If it is determined in step M21 that the engine is not in the lean burn operation region, the process proceeds to step M26 to determine whether the engine is in the stoichiometric operation region shown in FIG. If it is determined that the engine is in the stoichiometric operation region, the process proceeds to step M27 to determine whether or not the stoichiometric flag is set. At first, since the stoichiometric flag is not set, the process proceeds to step M28, resets other flags that have been set up to that time, sets the stoichiometric flag, and then sets the stoichiometric initial setting in step M29. Control is performed in the “Stoichio” cooling mode in step M30.

  If it is determined in step M27 that the stoichiometric flag is set, the process proceeds to step M30 and control in the “stoichio” cooling mode is performed.

  The initial setting for stoichiometric performed at step M29 is to set the cooling water supply ratios X, Y, Z, and W to the cooling water passage 20 and the bypass passage 21 to 0, 100, 0, and 0%, respectively. It is.

  The “stoichio” cooling mode in the step of M30 is a mode for preventing boiling of the cooling water during operation of the engine at the stoichiometric air-fuel ratio, and the cooling water passage 20 and the initial value set in the step of M29. The supply ratios X, Y, Z, and W of the cooling water to the bypass passage 21 are appropriately corrected, and the control unit 23 adjusts the opening degree of the first to fourth flow control valves 20 based on this.

The procedure of the “stoichio” cooling mode in this embodiment is shown in FIG. That is, it is first determined in step S42 whether or not the detection signal Tc from the first water temperature sensor 24c is higher than the reference temperature _TRc . Here, when it is determined that the detection signal Tc is higher than the reference temperature _TRc , that is, it is necessary to cool the combustion chamber 13 to prevent boiling of the cooling water, the routine proceeds to step S43 to cool the combustion chamber. The cooling water supply ratio X to the water passage 20c is increased by 1 (%), the process proceeds to step S44, and the cooling water supply ratio Y to the exhaust port cooling water passage 20p is calculated, and then the process returns to step M16.

If it is determined in step S42 that the detection signal Tc from the first water temperature sensor 24c is equal to or higher than the reference temperature T _Rc , the process proceeds to step S45 and the detection signal Tt from the third water temperature sensor 24t is changed to the reference temperature. It is determined whether it is higher than _TRt . If it is determined that the detection signal Tt is higher than the reference temperature T _Rt , that is, it is necessary to cool the supercharger 12 to prevent the cooling water from boiling, the routine proceeds to step S46 and supercharging is performed. The cooling water supply ratio Z to the machine cooling water passage 20t is increased by 1 (%), and the process proceeds to step S44 to calculate the cooling water supply ratio Y to the exhaust port cooling water passage 20p. If it is determined in step S45 that the detection signal Tt is equal to or lower than the reference temperature T _Rt , that is, it is not necessary to change the cooling water supply ratio Z to the supercharger 12, the process proceeds to step S44. Then, the cooling water supply ratio Y to the exhaust port cooling water passage 20p is calculated.

  If it is determined in the previous step M26 that the engine is not in the stoichiometric operation region, that is, the engine is in the high load / high rotation region shown in FIG. 3, the process proceeds to step M31 and the high load / high rotation flag is set. It is determined whether or not it has been done. At first, since the high load high rotation flag is not set, the process proceeds to step M32 to reset other flags set up to that time and set the high load high rotation flag. Initial setting for high load rotation is performed, and control in the “high load high rotation” cooling mode is performed in step M34.

  If it is determined that the high load / high rotation flag is set in step M31, the process proceeds to step M34 and the control in the “high load / high rotation” cooling mode is performed.

  The initial setting for high load and high rotation performed in step M33 is to set the cooling water supply ratios X, Y, Z, and W to the cooling water passage 20 and the bypass passage 21 to 50, 50, 0, and 0%, respectively. Is to set.

  The "high load high rotation" cooling mode in step M34 reduces the exhaust gas temperature during high load high rotation of the engine to improve fuel efficiency and protect the catalyst, and prevents boiling of the cooling water and knocking. In this mode, the ratio W of cooling water to the bypass passage 21 is maintained at 0%. And the supply ratio X, Y, Z of the cooling water with respect to the cooling water channel | path 20 is correct | amended appropriately with respect to the initial value set by the step of M33, and the control unit 23 makes 1st-3rd flow volume based on this. The opening degree of the control valves 20c, 20p, and 20t is adjusted, and the wastegate valve 11 of the supercharger 12, the ignition timing, and the fuel supply amount are also controlled as necessary.

FIG. 9 shows the procedure of the “high load high rotation” cooling mode in this embodiment. That is, first in S47, it is determined whether or not the detection signal Tt from the third water temperature sensor 24t is higher than the reference temperature _TRt . If it is determined that the detection signal Tt is higher than the reference temperature T _Rt , that is, it is necessary to cool the supercharger 12 to prevent the cooling water from boiling, the routine proceeds to step S48 and the combustion chamber is reached. feed rate X of the cooling water for the cooling water passage 20c and the exhaust port cooling water passage 20p, Y is preset minimum feed rate X _min, whether a Y _min or more judges.

In step S48, the supply ratios X and Y of the cooling water to the cooling water passages 20c and 20p are equal to or greater than the minimum supply ratio X _min and Y _min . When it is determined that the cooling water supply ratio Z to the supercharger cooling water passage 20t can be increased by reducing Y, the process proceeds to step S49 to supply the cooling water supply ratio to the cooling water passages 20c and 20p. X and Y are respectively lowered by 0.5 (%) and the supply ratio Z of the cooling water to the supercharger cooling water passage 20t is raised by 1 (%), and then the process returns to step M16. The minimum supply ratios X _min and Y _min are minimum supply ratios for preventing boiling of the cooling water flowing in the cooling water passages 20c and 20p.

The cooling water passage 20c at S48 in step, feed rate X of the cooling water for 20p, Y is minimum feed rate X _min, when it is determined that less than Y _min flows through the supercharger cooling water passage 20t There is a possibility that the cooling water will boil. However, since the supply ratio Z of the cooling water to the supercharger cooling water passage 20t cannot be increased, the process proceeds to step S50, the wastegate valve 11 of the supercharger 12 is held open, and the supercharger 12 Is temporarily stopped. As a result, the bearing portion is prevented from being overheated as the exhaust temperature Te rises.

If it is determined in S47 that the detection signal Tt is equal to or lower than the reference temperature T _Rt , that is, it is not necessary to change the cooling water supply ratio Z to the supercharger 12, the process proceeds to step S51 and the first water temperature is changed. It is determined whether or not the detection signal Tc from the sensor 24c is higher than the reference temperature _TRc . If it is determined that the detection signal Tc is higher than the reference temperature _TRc , that is, it is necessary to cool the combustion chamber 13 to prevent boiling of the cooling water, the routine proceeds to step S52 and the exhaust port is cooled. feed rate Y of the cooling water to water passage 20p is equal to or minimal feed rate Y _min or more.

Instead of determining whether or not the detection signal Tc is higher than the reference temperature T _Rc in step S51, it may be determined whether or not knocking has occurred using a knock sensor.

Feed rate Y of the cooling water against the exhaust port cooling water passage 20p at S52 in steps described above is minimal feed rate Y _min or more, i.e. the combustion chamber by reducing the feed rate Y of the cooling water to the exhaust port cooling water passage 20p When it is determined that the cooling water supply ratio X to the cooling water passage 20c can be increased, the process proceeds to step S53, and the cooling water supply ratio X to the combustion chamber cooling water passage 20c is increased by 1 (%). On the other hand, the supply ratio Y of the cooling water to the exhaust port cooling water passage 20p is lowered by 1 (%). In contrast, when the feed rate Y of the cooling water against the exhaust port cooling water passage 20p is determined to less than minimum feed rate Y _min at S52 in step cooling water boils flowing combustion chamber cooling water passage 20c The possibility to do arises. However, since the cooling water supply ratio X to the combustion chamber cooling water passage 20c cannot be increased, the routine proceeds to step S54, and the ignition timing is retarded, for example, by 1 degree via the igniter 29, so that the output is temporarily reduced. Thus, the temperature rise of the combustion chamber 13 is suppressed.

When it is determined in step S51 that the detection signal Tc from the first water temperature sensor 24c is equal to or lower than the reference temperature _TRc , that is, it is not necessary to change the cooling water supply ratio X to the combustion chamber cooling water passage 20c. In step S55, it is determined whether the detection signal Tp from the second water temperature sensor 24p is higher than the reference temperature _TRp . If it is determined that the detection signal Tp is higher than the reference temperature T _Rp , that is, it is necessary to cool the exhaust port 15, the process proceeds to step S56 and the cooling water is supplied to the combustion chamber cooling water passage 20c. It is determined whether the ratio X is greater than the minimum supply ratio _Xmin .

Instead determine higher or not than the detection signal Tp is the reference temperature T _Rp at S55 in step, the upper limit value of the catalyst temperature of the catalyst temperature Ts detected by the catalyst temperature sensor 27 is set in advance, that is the catalyst Is higher than the upper limit temperature at which the exhaust gas temperature is not damaged, or the exhaust temperature Te detected by the exhaust temperature sensor 28 is higher than the upper limit value of the exhaust temperature at which the preset catalyst is not damaged by heat. It may be determined whether or not the value is too high.

In step S56, the supply ratio X of the cooling water to the combustion chamber cooling water passage 20c is larger than the minimum supply ratio _Xmin , that is, the supply ratio X of the cooling water to the combustion chamber cooling water passage 20c is reduced to reduce the exhaust port. When it is determined that the cooling water supply ratio Y to the cooling water passage 20p can be increased, the process proceeds to step S57, and the cooling water supply ratio X to the combustion chamber cooling water passage 20c is lowered by 1 (%). On the other hand, the cooling water supply ratio Y to the exhaust port cooling water passage 20p is increased by 1 (%). In contrast, when the feed rate X of the coolant with respect to the combustion chamber cooling water passage 20c is equal to or less than the minimum feed rate X _min is the cooling water flowing through the exhaust port cooling water passage 20p boiling at S56 in step The possibility to do arises. However, since the cooling water supply ratio Y to the exhaust port cooling water passage 20p cannot be increased, the routine proceeds to step S58 to increase the amount of fuel injected from the fuel injection valve 14 by a predetermined amount, and the temperature of the exhaust gas is increased. Temporarily lowering the temperature of the exhaust port 15 is suppressed.

When it is determined in step S55 that the detection signal Tp from the second water temperature sensor 24p is equal to or lower than the reference temperature T _Rp , that is, there is no problem in cooling the combustion chamber 13, the exhaust port 15, and the supercharger 12. The output torque and fuel consumption are improved as follows. That is, whether the feed rate X of the cooling water is larger than the minimum feed rate X _min for transition to the combustion chamber cooling water passage 20c to S59 steps. Here, the supply ratio X of the cooling water to the combustion chamber cooling water passage 20c is greater than the minimum supply ratio _Xmin , that is, the supply ratio X of the cooling water to the combustion chamber cooling water passage 20c is reduced to reduce the exhaust port cooling water passage 20p. If it is determined that the cooling water supply ratio Y to the engine can be increased, the process proceeds to step S60 and the cooling water supply ratio X to the combustion chamber cooling water passage 20c is decreased by 1 (%), while the exhaust port The cooling water supply ratio Y to the cooling water passage 20p is increased by 1 (%), and the ignition timing is advanced by, for example, 1 degree via the igniter 29 in step S61, and the fuel supply amount is reduced to reduce the engine torque and fuel consumption. To improve. In this case, it is desirable that the final advance amount is stopped below MBT, and similarly, the final fuel supply amount is desirably stopped at an air-fuel ratio of 12.5 or less.

In step S59, the supply ratio X of the cooling water to the combustion chamber cooling water passage 20c is equal to or less than the minimum supply ratio X _min . That is, the supply ratio X of the cooling water to the combustion chamber cooling water passage 20c is reduced to reduce the exhaust port. If it is determined that the supply ratio Y of the cooling water to the cooling water passage 20p cannot be increased, the process returns to step M16 without doing anything.

  In this way, it is possible to optimally cool each cooling unit according to the operating state of the engine.

  It will be readily understood by those skilled in the art that the present invention can be applied not only to a spark ignition type internal combustion engine but also to a cooling control device for a compression ignition type internal combustion engine. In addition, the types of cooling modes are not limited to “cold start”, “idle”, “lean burn”, “stoichio”, “high load and high rotation”, but the required vehicle characteristics and the engine to be installed. It should be understood that it can be appropriately changed depending on the type and its auxiliary equipment.

  For example, in an engine that includes a first cylinder group that is supplied with fuel that is greater than the stoichiometric air-fuel ratio and a second cylinder group that can be supplied with fuel that is less than the stoichiometric air-fuel ratio, the first cylinder It is effective to form first and second cooling water supply passages for separately supplying cooling water to the combustion chamber group of the group and the combustion chamber group of the second cylinder group. In this case, the control unit supplies a cooling medium supply rate for cooling the combustion chamber group of the second cylinder group to be lower than a supply rate of the cooling medium for cooling the combustion chamber group of the first cylinder group. Thus, the opening degree of the flow control valve 20 interposed in the first and second cooling water supply passages is controlled by the control unit 23, respectively. As a result, the combustion chamber group of the second cylinder group is not excessively cooled, and it is possible to prevent a problem that the exhaust gas temperature is excessively lowered and impairs the activation of the catalyst.

  The type of engine that can employ bank control for desulfurizing the sulfur component adhering to the catalyst is not limited to the V type, but may be an in-line type. In the case of an in-line engine, a dual exhaust manifold is used. For example, in an in-line four-cylinder engine, the first and fourth cylinder groups may be divided into the second and third cylinder groups.

  In the above-described embodiment, the first to third water temperature sensors 24c, 24p, and 24t are incorporated in the cooling water passage 20 to detect the temperatures Tc, Tp, and Tt of the cooling water flowing through them. These temperatures Tc, Tp, Tt can also be estimated from the rotational speeds of the sensor 28 and the supercharger 12 and the flow rate of the cooling water flowing through the cooling water passage 20. When this method is adopted, the first to third water temperature sensors 24c, 24p, and 24t can be omitted, and the component cost can be reduced.

  The flow rate of the cooling water flowing through the cooling water passage 20 can be calculated by integrating the discharge amount of the cooling water from the cooling water pump 17 and the opening degree of the first to fourth flow control valves 20. The discharge amount of the cooling water from the cooling water pump 17 is substantially proportional to the engine rotation number as shown in FIG. 10 showing the relationship between the engine rotation speed Ne and the cooling water discharge amount from the cooling water pump 17. Therefore, based on the engine speed Ne detected by the engine speed sensor 26, the coolant discharge amount from the coolant pump 17 is read out from the map of FIG. 10, and this value and the first to fourth flow control valves 20 The flow rate of the cooling water flowing through the cooling water passage 20 is obtained by integrating the opening degree.

  The temperature Tc of the cooling water flowing through the combustion chamber cooling water passage 20c decreases as the exhaust temperature Te detected by the exhaust temperature sensor 28 is lower and the flow rate of the cooling water flowing through the combustion chamber cooling water passage 20c increases. The exhaust gas temperature Te tends to increase as the exhaust gas temperature Te increases and the flow rate of the cooling water flowing through the combustion chamber cooling water passage 20c decreases. That is, the temperature Tc of the cooling water flowing through the combustion chamber cooling water passage 20c can be read from a map as shown in FIG. 11 showing the relationship between the exhaust temperature Te and the flow rate of the cooling water flowing through the combustion chamber cooling water passage 20c.

  Further, the temperature Tp of the cooling water flowing through the exhaust port cooling water passage 20p decreases as the exhaust temperature Te detected by the exhaust temperature sensor 28 is lower and the flow rate of the cooling water flowing through the exhaust port cooling water passage 20p increases. Conversely, the higher the exhaust temperature Te and the lower the flow rate of the cooling water flowing through the exhaust port cooling water passage 20p, the higher the tendency. That is, the temperature Tp of the cooling water flowing through the exhaust port cooling water passage 20p can be read from a map as shown in FIG. 12 showing the relationship between the exhaust temperature Te and the flow rate of the cooling water flowing through the exhaust port cooling water passage 20p.

  Further, the temperature Tt of the cooling water flowing through the supercharger cooling water passage 20t is low in the supercharger rotation speed Nt per unit time detected by the supercharger rotation speed sensor, and the supercharger cooling water passage 20t. The higher the flow rate of the flowing coolant, the lower the flow rate. Conversely, the higher the turbocharger rotation speed Nt, and the lower the flow rate of the coolant flowing through the supercharger coolant passage 20t, the higher the trend. That is, the temperature Tt of the cooling water flowing through the supercharger cooling water passage 20t is obtained from a map as shown in FIG. 13 showing the relationship between the supercharger rotation speed Nt and the flow rate of the cooling water flowing through the supercharger cooling water passage 20t. Can be read.

  Similarly, instead of the catalyst temperature sensor 27, an exhaust A / F sensor for detecting the air-fuel ratio of the exhaust gas flowing therethrough is incorporated in the middle of the exhaust passage upstream of the catalyst, and is detected by the previous exhaust temperature sensor 28. It is also possible to predict the catalyst temperature Ts based on the exhaust temperature Te and the air-fuel ratio detected by the exhaust A / F sensor. That is, the catalyst temperature Ts decreases as the exhaust temperature Te decreases and the air-fuel ratio deviates from the stoichiometric air-fuel ratio. Conversely, the catalyst temperature Ts tends to increase as the exhaust temperature Te increases and the air-fuel ratio approaches the stoichiometric air-fuel ratio. have. That is, the catalyst temperature Ts can be read from a map as shown in FIG. 14 showing the relationship between the exhaust gas temperature Te and the air-fuel ratio.

It is a schematic diagram showing the concept of the cooling system in one Embodiment of the cooling control apparatus of the internal combustion engine by this invention. FIG. 2 is a control block diagram of the embodiment shown in FIG. 1. It is a map showing the relationship between the engine speed, load, and driving | running | working area | region in embodiment shown in FIG. It is a flowchart in embodiment shown in FIG. It is a flowchart showing the subroutine of the cold start in embodiment shown in FIG. 6 is a flowchart showing details of an idle subroutine in the flowchart shown in FIG. 5. 3 is a flowchart showing details of a lean burn subroutine in the flowchart shown in FIG. 1. 3 is a flowchart showing details of a stoichiometric subroutine in the flowchart shown in FIG. 1. It is a flowchart showing the detail of the subroutine of the high rotation high load in the flowchart shown in FIG. It is a graph showing the relationship between an engine speed and a cooling water pump discharge amount. It is a map showing the relationship between exhaust temperature, the amount of cooling water of a combustion chamber, and the cooling water temperature which cools an exhaust port. It is a map showing the relationship between exhaust temperature, the amount of exhaust port cooling water, and the cooling water temperature which cools a combustion chamber. It is a map showing the relationship between a supercharger rotation speed, the amount of supercharger cooling water, and the cooling water temperature which cools a supercharger. It is a map showing the relationship between exhaust temperature, air fuel ratio, and catalyst temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Wastegate valve 12 Supercharger 13 Combustion chamber 14 Fuel injection valve 15 Exhaust port 16 Radiator 17 Cooling water pump 18 Heater core 19 Circulation path 20c, 20p, 20t Cooling water path 21 Bypass path 22c, 22p, 22t, 22w Fourth flow control valve 23 Control unit 24c, 24p, 24t, 24w First to fourth water temperature sensors 25 Air flow sensor 26 Engine speed sensor 27 Catalyst temperature sensor 28 Exhaust temperature sensor 29 Igniter Ne Engine speed Tc, Tp, Tt, Tw Cooling water temperature Ts Catalyst temperature Te Exhaust temperature T _JW Cold start judgment temperature T _Rc , T _Rp , T _Rs , T _Rt , T _RW reference temperature X, Y, Z, W Cooling water supply ratio X _min , Y _min cooling Minimum supply ratio of water

Claims (12)

A cooling control device for an internal combustion engine, comprising: a plurality of cooling units to which cooling medium is supplied; and a plurality of cooling medium supply passages that respectively guide the cooling medium to the plurality of cooling units.
Adjusting means capable of changing the supply ratio of the cooling medium to the plurality of cooling units, respectively;
Control means for controlling the operation of the adjusting means so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed in accordance with the operating state of the engine. apparatus.   The cooling control apparatus for an internal combustion engine according to claim 1, wherein the cooling unit includes at least one of an exhaust port and a supercharger. A stoichiometric operation state in which an engine is operated at a stoichiometric air-fuel ratio, and a plurality of cooling sections to which a cooling medium is supplied, and a plurality of cooling medium supply passages that respectively guide the cooling medium to the plurality of cooling sections; A cooling control unit for an internal combustion engine that can be switched to a lean burn operation state in which the engine is operated with fuel set to be less than the air-fuel ratio,
Adjusting means capable of changing the supply ratio of the cooling medium to the plurality of cooling units, respectively;
Control means for controlling the operation of the adjusting means so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed in accordance with the operating state of the engine, and the cooling unit includes an exhaust port and a supercharger The control means includes a cooling medium supply amount to at least one of the exhaust port and the supercharger in the lean burn operation state is smaller than a cooling medium supply amount in the stoichiometric operation state. An internal combustion engine cooling control apparatus for controlling the operation of the adjusting means to be   The control means increases the supply ratio of the cooling medium supplied to at least one of the exhaust port and the supercharger as the temperature of the exhaust gas or the catalyst in the lean burn operation state is higher. An internal combustion engine cooling control apparatus according to claim 1.   The cooling control device according to claim 1, wherein the cooling unit includes a combustion chamber of an engine. A first cylinder group, a second cylinder group that can be supplied with less fuel than the stoichiometric air-fuel ratio, a plurality of cooling units each supplied with a cooling medium, and a cooling medium guided to the plurality of cooling units, respectively. A cooling control device for an internal combustion engine having a plurality of cooling medium supply passages,
Adjusting means capable of changing the supply ratio of the cooling medium to the plurality of cooling units, respectively;
Control means for controlling the operation of the adjusting means so that the supply ratio of the cooling medium to the plurality of cooling medium supply passages is changed according to the operating state of the engine, and the plurality of cooling sections are the first cooling section. A combustion chamber group of a cylinder group and a combustion chamber group of the second cylinder group, wherein the control means supplies a cooling medium supply ratio for cooling the combustion chamber group of the second cylinder group. An internal combustion engine cooling control apparatus that controls the operation of the adjusting means so as to be less than a supply ratio of a cooling medium for cooling a combustion chamber group of the cylinder group.   7. The fuel according to claim 6, wherein when the fuel less than the stoichiometric air-fuel ratio is supplied to the second cylinder group, the first cylinder group is supplied with more fuel than the stoichiometric air-fuel ratio. A cooling control apparatus for an internal combustion engine as described.   The cooling control apparatus for an internal combustion engine according to any one of claims 1 to 7, further comprising a bypass passage that allows the cooling medium to pass therethrough without being guided to the cooling unit.   The engine operating state includes at least one of a temperature of a cooling medium, a temperature of exhaust gas exhausted from the engine, and a temperature of a catalyst for purifying the exhaust gas. The cooling control apparatus for an internal combustion engine according to any one of claims 8 to 10.   9. The cooling control apparatus for an internal combustion engine according to claim 1, wherein the operating state of the engine includes an air-fuel ratio of the combustion gas.   The cooling control apparatus for an internal combustion engine according to any one of claims 1 to 10, wherein the operating state of the engine includes an engine speed and an output torque. 12. The cooling control apparatus for an internal combustion engine according to claim 1, wherein the control means controls the operation of the adjusting means so that the cooling medium does not boil.

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