JP2013087761A - Engine cooling water circulation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid disadvantage of introducing low temperature cooling water lower than a lower limit temperature to a heat exchanger while early introducing cooling water which is equal to or higher than the lower limit temperature to the heat exchanger.SOLUTION: This engine cooling water circulation system includes: a cylinder route 20 for circulating engine cooling water to a cylinder part Es; a head route 30 for circulating it to a head part Eh; and an EGR cooler 60 (heat exchanger) for introducing the cooling water which has circulated in the cylinder route 20 or the head route 30 to cool an EGR gas (prescribed fluid). The system adjusts a distribution ratio of the cooling water to both the routes 20 and 30 so that a cylinder temperature is higher than a head temperature upon warming-up of an engine. The system controls an introduction route of the cooling water so that at a point in time when the cylinder temperature rises up to the lower limit temperature, the cooling water is introduced from the cylinder route 20 to the EGR cooler 60, and thereafter at a point in time when the head temperature rises up to the lower limit temperature, the cooling water is introduced from the head route 30 to the EGR cooler 60.

Description

  The present invention relates to an engine coolant circulation system configured to introduce engine coolant into a heat exchanger such as an EGR cooler, an oil cooler, or a heater core.

  During the engine warm-up period, it is desirable to increase the temperature of the engine oil early to reduce the friction loss in the cylinder. Therefore, conventionally, the circulation path of the engine cooling water is branched into a cylinder path that circulates the cylinder part of the engine and a head path that circulates to the head part of the engine (see Patent Document 1). During the warm-up operation, the circulation flow rate in the cylinder path is made smaller than the circulation flow rate in the head path. According to this, since the temperature rise of the cylinder part is promoted in preference to the head part, the temperature rise of the engine oil can be promoted, and the friction loss in the cylinder during the warm-up operation can be reduced.

  Incidentally, when the water pump that circulates the cooling water is electrically operated, the circulation of the cooling water may be stopped during the warm-up operation, or may be driven while reducing the circulation flow rate of the cylinder path as described above. Also good. In addition, the thermostat operates so that the cooling water circulates around the radiator during the warm-up operation.

JP 2010-163920 A

  By the way, various heat exchangers that exchange heat with the cooling water described above are mounted on the vehicle. For example, an EGR cooler that cools a part of exhaust gas recirculated to the intake side (EGR gas), an oil cooler that cools engine oil, a heater core that heats air-conditioning air during vehicle interior heating, etc. Listed as an exchanger.

  And in such a heat exchanger, it is desirable not to introduce low-temperature (less than the lower limit temperature) cooling water. For example, when cooling water having a low temperature (for example, less than 60 ° C.) is introduced into the EGR cooler, the water component contained in the EGR gas is condensed in a state containing many oxidizing components, and the condensed water is discharged into the exhaust pipe. Corrosion of various metal parts. Further, when low-temperature (for example, less than 30 ° C.) cooling water is introduced into the oil cooler, the viscosity of the oil increases and friction loss in the cylinder increases. In addition, when low-temperature cooling water is introduced into the heater core, the time required to heat the vehicle interior to a desired temperature is increased.

  However, while it is desirable not to introduce low-temperature cooling water below the lower limit temperature, cooling water above the lower temperature is introduced into the heat exchanger at an early stage so that EGR gas cooling, oil cooling, heater core heating, etc. There is also a need to start early.

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to avoid the problem of introducing low-temperature cooling water having a temperature lower than the lower limit temperature into the heat exchanger, while cooling water having a temperature equal to or higher than the lower temperature limit. An object of the present invention is to provide an engine coolant control apparatus that is intended to be introduced early into a heat exchanger.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to the first aspect of the present invention, the cylinder path for circulating the cooling water for cooling the engine to the cylinder part of the engine, the head path for flowing the cooling water to the head part of the engine, the cylinder path or the head path And a heat exchanger that introduces the circulating cooling water and exchanges heat between the introduced cooling water and a predetermined fluid, and is configured to be capable of adjusting a distribution ratio of the cooling water to the cylinder path and the head path. It is assumed that the above applies.

  When the engine is warming up, a distribution control device that controls the distribution ratio so that the temperature of the cylinder portion is higher than the temperature of the head portion, and the temperature of the cylinder portion reaches a predetermined lower limit temperature. When the temperature rises, cooling water is introduced from the cylinder path to the heat exchanger. After that, when the temperature of the head portion rises to the lower limit temperature, cooling water is supplied from the head path to the heat exchanger. An introduction control device for controlling the introduction path of the cooling water so as to introduce the cooling water.

  According to the said invention, the following effects are exhibited by providing a distribution control apparatus. That is, since the temperature of the cylinder part (cylinder temperature) is controlled during warm-up so that the temperature of the head part (head temperature) is higher than that of the head part (head temperature), the increase in cylinder temperature is accelerated in preference to the head part temperature rise Is done. Therefore, since the temperature rise of the engine oil existing in the cylinder part is promoted, the friction loss in the cylinder during the warm-up operation can be reduced.

  During the warm-up operation in which the cylinder temperature is increased in this way, the temperature of the cooling water flowing through the cylinder path should rise faster than the cooling water flowing through the head path. In the above invention using this, the following effects are exhibited by providing the introduction control device.

  That is, since the cooling water in the cylinder path is introduced into the heat exchanger when the cylinder temperature rises to the lower limit temperature, the lower limit of the temperature is avoided while avoiding the problem of introducing the low-temperature cooling water below the lower limit temperature into the heat exchanger. It is possible to promptly introduce cooling water at a temperature or higher into the heat exchanger.

  In addition, when the head temperature reaches the lower limit temperature with a delay in increasing the cylinder temperature, the cylinder temperature should be higher than the head temperature. In the above invention in view of this point, since the cooling water is introduced from the head path to the heat exchanger when the head temperature rises to the lower limit temperature, the low-temperature (however, the lower limit temperature or higher) cooling water from the head path is heated. It will be introduced into the exchanger. Therefore, when the heat exchanger cools a predetermined fluid such as an EGR cooler or an oil cooler, the cooling capacity can be improved.

  According to a second aspect of the present invention, the introduction control device is configured such that the cylinder portion reaches the upper limit temperature set higher than the lower limit temperature even after the temperature of the head portion has increased to the lower limit temperature. The period until the temperature rises is controlled to allow cooling water to be introduced from the cylinder path to the heat exchanger.

  As described above, when the head temperature rises to the lower limit temperature, the cooling water is introduced from the head path to the heat exchanger as described above, but the cooling water alone from the head path is insufficient to introduce the heat exchanger. As a result, a sufficient amount of heat exchange may not be obtained. On the other hand, in the above invention, even after the head temperature has risen to the lower limit temperature, the cooling water introduction from the cylinder path is permitted during the period until the cylinder temperature rises to the upper limit temperature. It is possible to eliminate the concern that the amount introduced into the heat exchanger is insufficient.

  If the heat exchanger cools a predetermined fluid, such as an EGR cooler or oil cooler, after the cylinder temperature rises to the upper limit temperature, the introduction of cooling water from the cylinder path is prohibited and the cooling capacity It is desirable to avoid a decrease in the above.

  In the invention according to claim 3, the introduction control device includes an electromagnetic valve that controls a circulation amount of the cooling water to the heat exchanger or the radiator, a bypass path that bypasses the electromagnetic valve and distributes the cooling water, And a thermostat that opens the valve when the cooling water temperature rises to a relief temperature set higher than the lower limit temperature, and distributes the cooling water to the bypass path.

  According to the above invention, even when the electromagnetic valve of the introduction control device fails and the cooling water is not circulated from the cylinder path and the head path to the radiator or the heat exchanger, the thermostat operates as follows. It will be. That is, when the cooling water temperature rises to the relief temperature due to the failure, the cooling water can be distributed to the radiator or the heat exchanger through the bypass path. Therefore, even if the failure occurs, the fail-safe function can be exhibited so as to avoid the engine temperature from exceeding the relief temperature.

  According to a fourth aspect of the present invention, the heat exchanger has a cylinder heat exchanger that introduces cooling water from the cylinder path and a head heat exchanger that introduces cooling water from the head path. It is characterized by being configured.

  According to the above invention, since the cylinder heat exchanger and the head heat exchanger can be used properly according to the cooling water temperature, it is possible to accurately manage the predetermined fluid at the desired temperature in the heat exchanger. The desired temperature can be quickly achieved.

  According to a fifth aspect of the present invention, the introduction control device opens and closes a path that bypasses the heat exchanger from the cylinder path and opens and closes a path that flows from the cylinder path to the heat exchanger. And at least one of a side three-way valve and a head side three-way valve that opens and closes a path through which the heat exchanger bypasses the heat exchanger and opens and closes a path from the head path to the heat exchanger. It is characterized by that.

  According to the above invention, the valve that opens and closes the path that bypasses the heat exchanger from the cylinder path (or head path), and the valve that opens and closes the path that flows from the cylinder path (or head path) to the heat exchanger. Since the number of valves can be reduced as compared with the case where these are separately provided, the introduction control device can be downsized.

The schematic diagram of the engine-cooling-water circulation system concerning 1st Embodiment of this invention. In 1st Embodiment, the time chart explaining valve | bulb action | operation according to the change of a cooling water temperature. The flowchart explaining the control content which implement | achieves the valve | bulb action | operation of FIG. The schematic diagram of the engine-cooling-water circulation system concerning 2nd Embodiment of this invention. The schematic diagram of the engine-cooling-water circulation system concerning 3rd Embodiment of this invention. The schematic diagram of the engine-cooling-water circulation system concerning 4th Embodiment of this invention. The schematic diagram of the engine-cooling-water circulation system concerning 5th Embodiment of this invention.

  Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing an engine coolant circulation system according to this embodiment, and coolant discharged from a water pump 10 flows into a cylinder path 20 and a head path 30 described below. Since the water pump 10 is operated by the rotational driving force of the engine, cooling water is always discharged from the water pump 10 when the engine is driven.

  The cylinder path 20 is a circulation path of a water jacket formed in the cylinder part Es of the engine, and the cylinder part Es is cooled by flowing cooling water through the cylinder path 20. The head path 30 is a water jacket distribution path formed in the head section Eh of the engine, and the head section Eh is cooled by flowing cooling water through the head path 30.

  Incidentally, the cylinder part Es is a part that accommodates the piston of the engine so as to be able to reciprocate, and the head part Eh is a part that forms an intake port and an exhaust port. And since the head part Eh has much heat transmitted from a combustion chamber compared with the cylinder part Es, the material whose heat conductivity is higher than the cylinder part Es is used for the metal material of the head part Eh. Further, the target upper limit value (for example, 70 ° C.) of the head temperature Th is set lower than the target upper limit value (for example, 90 ° C.) of the cylinder temperature Ts.

  The cylinder path 20 and the head path 30 are connected in parallel, and the cooling water discharged from the water pump 10 is distributed to the cylinder path 20 and the head path 30 at a rate according to the valve open / close state of the distribution device 40 described later. Is done. Therefore, by controlling this distribution ratio, the cylinder temperature Ts and the head temperature Th can be controlled to be the above-described target values.

  Cooling water flowing out from the cylinder path 20 (hereinafter referred to as cylinder cooling water) can flow into the radiator 50 through the cylinder side outflow path 21 and can flow into the EGR cooler 60 through the cylinder side HE path 22. Yes. In other words, the circulation path on the downstream side of the cylinder path 20 branches into the cylinder-side outflow path 21 and the cylinder-side HE path 22.

  Cooling water flowing out from the head path 30 (hereinafter referred to as head cooling water) can flow into the radiator 50 through the head side outflow path 31 and can flow into the EGR cooler 60 through the head side HE path 32. Yes. In other words, the circulation path on the downstream side of the head path 30 branches into a head side outflow path 31 and a head side HE path 32.

  Incidentally, the radiator 50 is a heat exchanger that cools the cooling water by exchanging heat with the outside air. When the cooling water temperature is lower than the set temperature of the thermostat 51 (for example, 80 ° C.), the cooling water circulates bypassing the radiator 50 by closing the thermostat 51. Therefore, since the thermostat 51 is closed during the warm-up operation of the engine, the cooling water is not cooled by the radiator 50. On the other hand, when the warm-up operation is completed, the cooling water temperature rises to a temperature equal to or higher than the set temperature of the thermostat 51 and the thermostat 51 is opened, so that the cooling water is cooled by the radiator 50.

  The EGR cooler 60 is a heat exchanger (HE) provided in an EGR system that recirculates a part of exhaust gas (EGR gas) to the intake side, and cools the EGR gas to improve intake charging efficiency. Is. Specifically, the EGR cooler is connected to the circulation path of the cooling water so that the cooling water flowing through the cylinder path 20 or the head path 30 is introduced into the EGR cooler, and the introduced cooling water and EGR gas (predetermined fluid) The EGR gas is cooled by exchanging heat.

  Next, the configuration of the distribution device 40 will be described.

  The distributor 40 includes a valve Vs1 for adjusting the opening degree of the cylinder side outflow path 21, a valve Vs2 for adjusting the opening degree of the cylinder side HE path 22, a valve Vh1 for adjusting the opening degree of the head side outflow path 31, and the head side. A valve Vs2 for adjusting the opening degree of the HE path 32 is provided. These valves Vs1, Vs2, Vh1, and Vh2 are electromagnetic valves having electromagnetic coils, and the electronic control unit (ECU 70) controls the energization of these electromagnetic coils, so that each valve opening, that is, each The opening degree of the paths 21, 22, 31, 32 is controlled. The distribution device 40 and the ECU 70 correspond to an “introduction control device”.

  The valves Vs1 and Vs2 control the circulation path of the cylinder cooling water. By controlling the ratio between the opening degree of the valve Vs1 and the opening degree of the valve Vs2, the amount of the cylinder cooling water flowing to the radiator 50 and the EGR cooler are controlled. The ratio to the amount flowing to 60 is controlled. The valves Vh1 and Vh2 control the circulation path of the head cooling water. By controlling the ratio between the opening degree of the valve Vh1 and the opening degree of the valve Vh2, the amount of the head cooling water flowing to the radiator 50 and the EGR cooler are controlled. The ratio to the amount flowing to 60 is controlled.

  In other words, the ECU 70 performs control (introduction control) for switching between the cylinder-side HE path 22 and the head-side HE path 32 as the coolant introduction path to the EGR cooler 60, and to the EGR cooler 60. The flow rate of the introduced cooling water is controlled.

  Furthermore, the flow rate of the cylinder cooling water flowing through the cylinder path 20 is determined by the sum SUMs of the opening degrees of both valves Vs1, Vs2, and the head cooling water flowing through the head path 30 is determined by the total sum SUMh of the opening degrees of both valves Vh1, Vh2. Is determined.

  In other words, the ECU 70 adjusts the ratio between the total opening SUMs of both valves Vs1 and Vs2 and the total opening SUMh of both valves Vh1 and Vh2, so that the cooling water to the cylinder path 20 and the head path 30 is adjusted. Control distribution ratio (distribution control). Thus, the ratio between the cooling capacity for the cylinder part Es and the cooling capacity for the head part Eh is controlled, and the cylinder temperature Ts and the head temperature Th are both controlled to be less than the target upper limit value.

  It can be said that the ECU 70 controls the ratio of the cylinder cooling water distributed to the EGR cooler 60 and the radiator 50 and the ratio of the head cooling water distributed to the EGR cooler 60 and the radiator 50. The ECU 70 when performing the distribution control corresponds to a distribution control device, and the ECU 70 when performing the introduction control corresponds to an introduction control device.

  Here, as described above, since the water pump 10 is operated by the rotational driving force of the engine, it is necessary to control the total flow rate of the cylinder cooling water and the head cooling water to be a predetermined amount or more. That is, it is prohibited to fully close all the four valves Vs1, Vs2, Vh1, and Vh2 so that the total flow rate does not become zero.

  The cylinder temperature Ts is detected by a temperature sensor Ss provided at the outlet portion of the cylinder path 20, and the head temperature Th is detected by a temperature sensor Sh provided at the outlet portion of the head path 30. Then, according to the cylinder temperature Ts and the head temperature Th, the operation of the distributor 40, that is, the opening / closing operation of the four valves Vs1, Vs2, Vh1, Vh2, is controlled by the ECU 70.

  Next, details of the above-described distribution control will be described with reference to FIG. FIG. 2A shows changes in the cylinder temperature Ts and the head temperature Th, and shows how the temperature of the cooling water rises from time t1 when the engine is cold started.

  When the engine whose cooling water temperature is lower than the set temperature of the thermostat 51 is cold-started, the thermostat 51 is opened to perform a warm-up operation that bypasses the radiator 50 and circulates the cooling water. During the warm-up operation, the operation of the distribution device 40 is controlled (distribution control) so that the temperature increase of the cylinder portion Es is promoted in preference to the head portion Eh.

  Specifically, by controlling the distributor 40 so that the circulating flow rate in the cylinder path 20 is smaller than the circulating flow rate in the head path 30, the cylinder cooling water is retained in the cylinder path 20 for a long time. Thereby, as shown in FIG. 2A, the rising speed of the cylinder temperature Ts becomes faster than the rising speed of the head temperature Th, and Ts> Th. Therefore, the temperature rise of the engine oil located in the cylinder part Es is promoted, and the increase in the viscosity of the engine oil during the warm-up operation can be suppressed. Therefore, friction loss with the piston (not shown) in the cylinder part Es can be reduced.

  Incidentally, as shown in FIG. 1, the cylinder path 20 is branched into a plurality of paths inside the cylinder part Es, thereby promoting the retention of cylinder cooling water in the cylinder path 20 for a long time.

  Next, details of the above-described introduction route control will be described with reference to FIGS. Each of (b) to (e) shows changes in the opening of the four valves Vs1, Vs2, Vh1, and Vh2.

  Here, when cooling water having a temperature lower than a predetermined lower limit temperature Tlow (for example, 60 ° C.) is introduced into the EGR cooler 60, the water component contained in the EGR gas condenses in a state containing many oxidizing components, The condensed water corrodes various metal parts such as exhaust pipes. Therefore, until the time point t2 when the temperature of the cooling water rises to the lower limit temperature Tlow, the valves Vs2 and Vh2 are fully closed to prohibit the introduction of the cooling water to the EGR cooler 60.

  In the example of FIG. 2D, the valve Vs1 is operated in a half-open state during the period from t1 to t2, and the cylinder cooling water is released from the cylinder-side outflow path 21, but the valve Vs1 is fully closed. It may be operated so that the circulation flow rate of the cylinder cooling water becomes zero. In any case, the circulation flow rate of the cylinder cooling water is made smaller than the circulation flow rate of the head cooling water.

  When the engine is cold started, the cylinder temperature Ts rises faster than the head temperature Th due to the above-described distribution control. Therefore, the cylinder cooling water should reach the lower limit temperature Tlow earlier than the head cooling water. Therefore, in the present embodiment, first, at time t2 when the cylinder temperature Ts reaches the lower limit temperature Tlow, the valve Vs2 is fully opened to introduce cylinder cooling water into the EGR cooler 60.

  After that, at the time t3 when the head temperature Th reaches the lower limit temperature Tlow after the increase in the cylinder temperature Ts, Ts> Th should be satisfied. Therefore, in the present embodiment, at time t3 when Th = Tlow, the valve Vs2 is fully closed and the valve Vh2 is fully open, so that the head cooling water is introduced into the EGR cooler 60. Switch the cooling water introduction path.

  In the example of FIG. 2D, the valve Vs1 is fully closed during the period from t2 to t3, and the entire amount of cylinder cooling water is introduced into the EGR cooler 60. However, the flow rate is excessive. In that case, part of the cylinder coolant may be released from the cylinder-side outflow path 21 by operating the valve Vs1 in a half-open state. Further, when the amount of cylinder cooling water introduced into the EGR cooler 60 becomes too small, the valve Vh2 is operated in a half-open state to introduce a part of the head cooling water from the head-side outflow path 31, thereby cooling the cylinder. Both water and head cooling water may be introduced. In any case, in the period from t2 to t3, the cylinder cooling water is introduced to the EGR cooler 60 with priority over the head cooling water.

  In short, the cylinder cooling water is allowed to be introduced into the EGR cooler 60 even after the head temperature Th has risen to the lower limit temperature Tlow. However, after the cylinder temperature Ts rises to the upper limit temperature High set higher than the lower limit temperature, introduction of cylinder cooling water into the EGR cooler 60 is prohibited.

  Incidentally, the lower limit temperature Tlow (for example, 60 ° C.) <The target upper limit value of the head temperature Th (for example, 70 ° C.) <The target upper limit value of the cylinder temperature Ts (for example, 90 ° C.) <The upper limit temperature High (for example, 100 ° C.). .

  FIG. 3 is a flowchart showing a procedure for controlling the distribution device 40 by the microcomputer of the ECU 70, and this process is repeatedly executed at a predetermined cycle during engine operation.

  First, in step S10 shown in FIG. 3, it is determined whether or not the engine is warming up by cold start. For example, when the cylinder temperature Ts detected by the temperature sensor Ss is less than 90 ° C., it is determined that the warm-up operation is being performed.

  If it is determined that the warm-up operation is being performed (S10: YES), in the subsequent step S11, the above-described distribution control is performed, and the cylinder temperature Ts is given priority over the head temperature Th (Ts> Th). In subsequent steps S12 and S13, it is determined whether or not the head temperature Th is equal to or higher than the lower limit temperature Tlow, and whether or not the cylinder temperature Ts is equal to or higher than the lower limit temperature Tlow.

  If Th <Tlow and Ts <Tlow (S12: NO and S13: NO), it is regarded as the period t1 to t2 in FIG. 2, and the process proceeds to step S14. Then, the valves Vs2 and Vh2 are fully closed to close the cylinder-side HE path 22 and the head-side HE path 32, and the cooling water introduction to the EGR cooler 60 is waited.

  If Th <Tlow and Ts ≧ Tlow (S12: NO and S13: YES), it is regarded as the period t2 to t3 in FIG. 2, and the process proceeds to step S15. And valve | bulb Vs2 is fully opened in order to open the cylinder side HE path | route 22, and the cylinder cooling water to the EGR cooler 60 is introduced.

  If Th ≧ Tlow (S12: YES), it is considered that it is after time t3 in FIG. 2, and the process proceeds to step S16. Then, the valve Vh <b> 2 is fully opened to open the head-side HE path 32, and the head cooling water is introduced into the EGR cooler 60.

  When the cooling water is introduced into the EGR cooler 60 in steps S15 and S16, the amount of cooling water introduced into the EGR cooler 60 and the relief amount for bypassing the EGR cooler 60 are determined in step S17. It adjusts according to the discharge amount.

  For example, when only the cylinder cooling water or the head cooling water is introduced and the required introduction amount into the EGR cooler 60 is too small, both the cylinder cooling water and the head cooling water are introduced into the EGR cooler 60 at the same time. Specifically, the head cooling water is also introduced into the EGR cooler 60 when the cylinder cooling water is introduced in step S15. Alternatively, the cylinder cooling water is also introduced into the EGR cooler 60 when the head cooling water is introduced in step S16.

  On the other hand, if the total amount of cylinder cooling water or head cooling water is excessive with respect to the required introduction amount, the relief amount from the cylinder side outflow path 21 or the head side outflow path 31 is increased, and the EGR cooler 60 is increased. Adjust the cooling water introduction amount. Specifically, when the cylinder cooling water is introduced in step S15, the opening degree of the valve Vs1 is increased to increase the relief amount from the cylinder-side outflow path 21. Alternatively, when the head cooling water is introduced in step S16, the opening degree of the valve Vh1 is increased to increase the relief amount from the head side outflow path 31.

  If it is determined in step S10 that the engine is not warming up (S10: NO), in the subsequent step S18, the circulating flow rate of the cylinder cooling water is set so that the cylinder temperature Ts and the head temperature Th are less than the target upper limit values. And the distribution ratio of the circulation flow rate of the head cooling water is controlled. Specifically, the flow rate of the cylinder cooling water determined by the sum SUMs of the opening amounts of the two valves Vs1 and Vs2 and the flow rate of the head cooling water determined by the sum SUMh of the opening amounts of the two valves Vh1 and Vh2. Control the rate.

  In subsequent step S <b> 19, the valve Vh <b> 2 is fully opened to open the head-side HE path 32, and the head cooling water is introduced into the EGR cooler 60. Even when the head cooling water is introduced in step S19 after the warm-up operation is completed, the process proceeds to step S17, and the introduction amount of the cooling water to the EGR cooler 60 and the relief amount for bypassing the EGR cooler 60 are as follows. It adjusts according to the discharge amount of the water pump 10.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) The cooling water is configured to flow separately to the cylinder path 20 and the head path 30, and the ratio of the flow rates of the cylinder cooling water and the head cooling water is distributed and controlled, so that Ts> Th during the warm-up operation. Control to be. Thereby, since the temperature rise of the engine oil which exists in the cylinder part Es is accelerated | stimulated, the friction loss in the cylinder part Es at the time of warming-up operation can be reduced.

  (2) Since the warm-up operation is started using the fact that Ts> Th is achieved by the distribution control, the cylinder cooling water is first introduced into the EGR cooler 60 at time t2 when Ts> Tlow. In addition, it is possible to realize early introduction of cooling water (cylinder cooling water) having a temperature equal to or higher than the lower limit temperature Tlow to the EGR cooler 60 while avoiding the problem of introducing low-temperature cooling water having a temperature lower than the lower limit temperature Tlow into the EGR cooler 60.

  (3) Since the head cooling water having a temperature lower than that of the cylinder cooling water is introduced into the EGR cooler 60 at the time t3 when Th> Tlow after the cylinder cooling water is introduced, the cooling capacity of the EGR cooler 60 can be improved. .

  (4) Even after the time point t3 when the head temperature Th rises to the lower limit temperature Tlow, if the cylinder temperature Ts is lower than the upper limit temperature High, the introduction of the cylinder cooling water is permitted, so the cooling water to the EGR cooler 60 The concern about the shortage of introduction can be resolved.

(Second Embodiment)
In this embodiment shown in FIG. 4, a thermostat 41 and a bypass path 42 described below are added to the engine coolant circulation system shown in FIG. Hereinafter, the configuration of FIG. 4 will be described focusing on differences from FIG. In FIG. 5, the description of the same reference numerals as those in FIG.

  One end of a bypass path 42 is connected to the cylinder-side outflow path 21 and the cylinder-side HE path 22 and the head-side outflow path 31 and the head-side HE path 32. The other end of the bypass path 42 is connected to a path that leads to the radiator 50. A thermostat 41 is provided in the bypass path 42. In this thermostat 41, when the cooling water temperature rises to the relief temperature set higher than the lower limit temperature Tlow.

  When the thermostat 41 opens, the cooling water flowing into the distribution device 40 from the cylinder path 20 and the head path 30 flows to the radiator 50 through the bypass path 42. That is, the cooling water circulates bypassing the four valves Vs1, Vs2, Vh1, and Vh2.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, the following effects are also exhibited. That is, all four valves Vs1, Vs2, Vh1, and Vh2 are in a fully closed state, and if a failure occurs in which none of the valves can be opened, the cooling water is cooled by the radiator 50. As it disappears, the cooling water temperature rises. However, since the thermostat 41 opens when the cooling water temperature rises to the relief temperature, the cooling water flows to the radiator 50 through the bypass path 42 and is cooled. Therefore, the fail-safe function is exhibited so as to avoid the engine temperature from exceeding the relief temperature.

(Third embodiment)
In the second embodiment shown in FIG. 4, a bypass path 42 is provided so as to bypass the four valves Vs1, Vs2, Vh1, and Vh2. In contrast, in the present embodiment shown in FIG. 5, bypass paths 42s and 42h are provided so as to bypass the valves Vs2 and Vh2 that open and close the cylinder side HE path 22 and the head side HE path 32. Thermostats 41s and 41h are provided in the bypass paths 42s and 42h, respectively.

  As described above, also in the present embodiment, the same effects as those in the second embodiment are exhibited. That is, even if a failure occurs in which none of the four valves Vs1, Vs2, Vh1, and Vh2 can be opened, the thermostats 41s and 41h are opened when the cooling water temperature rises to the relief temperature. Since the valve operates, the cooling water flows to the radiator 50 through the bypass paths 42s and 42h and is cooled. Therefore, the fail-safe function is exhibited so as to avoid the engine temperature from exceeding the relief temperature.

(Fourth embodiment)
The first to third embodiments are examples in which the EGR cooler 60 is applied as a heat exchanger that introduces cooling water and exchanges heat with a predetermined fluid (EGR gas). On the other hand, the present embodiment shown in FIG. 6 is an example in which the heater cores 60h and 60s for heating the conditioned air (predetermined fluid) blown into the passenger compartment are applied as the heat exchanger.

  These heater cores 60 h and 60 s are arranged in parallel in the air conditioning case 61 and are installed so that the conditioned air flowing through the air conditioning case 61 passes through. The air conditioning case 61 is provided with a switching door 62 that switches the flow path of the conditioned air so that one of the heater cores 60h and 60s is opened and the other is closed. The switching door 62 is controlled to rotate by an electric motor. For example, the head cooling water use mode (the state shown in FIG. 6) in which the heater core 60s is closed to open the heater core 60h, and the heater core 60s is closed to turn off the heater core 60s. Switch to the cylinder coolant usage mode that opens.

  The operation of the distribution device 40 in the present embodiment is the same as in the first to third embodiments. Therefore, since the cylinder cooling water is introduced into the heater core 60s (cylinder heat exchanger) in the period from t1 to t2 in FIG. 2, the cylinder cooling water use mode is switched in this period. Moreover, since the head cooling water is introduced into the heater core 60h (head heat exchanger) in the period t2 to t3 in FIG. 2, the head cooling water use mode is switched in this period.

(Fifth embodiment)
In the first to fourth embodiments, the distribution device 40 is constituted by the four valves Vs1, Vs2, Vh1, and Vh2, and these valves adjust the opening degree of each of the paths 21, 22, 31, and 32. It is a two-way valve. On the other hand, in the present embodiment shown in FIG. 7, instead of these two-way valves, a three-way valve Vs3 (cylinder side three-way valve) and a three-way valve Vh3 (head side three-way valve) are adopted.

  Specifically, the three-way valve Vs3 adjusts the opening degree of the cylinder side HE path 22 and adjusts the opening degree of the cylinder side HE path 22. The three-way valve Vh3 adjusts the opening degree of the head side HE path 32 and adjusts the opening degree of the head side HE path 32.

  As described above, according to the present embodiment, the number of valves can be reduced as compared with the case where the valves Vs1 and Vs2 are provided in each of the cylinder-side outflow path 21 and the cylinder-side HE path 22. Further, the number of valves can be reduced as compared with the case where the valves Vh1 and Vh2 are provided in the head-side outflow path 31 and the head-side HE path 32, respectively. Accordingly, the distribution device 40 can be reduced in size.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Moreover, you may make it combine the characteristic structure of each embodiment arbitrarily, respectively.

  In each of the above-described embodiments, the heater cores 60h and 60s and the EGR cooler 60 are applied as heat exchangers that introduce and use cooling water. However, an oil cooler that cools engine oil (predetermined fluid) with cooling water is used as the heat exchanger. It may be applied as an exchanger.

  In the fifth embodiment shown in FIG. 7, the three-way valves Vs3 and Vh3 are provided in both the cylinder-side HE path 22 and the head-side HE path 32, but the three-way valve is provided in one of the paths, Two two-way valves may be provided in the path.

  In the fourth embodiment shown in FIG. 6, the two heater cores 60h and 60s are arranged in parallel in the air conditioning case 61. However, the air conditioning air passes through both heater cores 60h and 60s in series. You may make it do. In this case, the switching door 62 can be eliminated and the conditioned air can be heated by both the heater cores 60h and 60s, so that the heating capacity can be improved.

  In the example of FIG. 6, the cylinder heat exchanger and the head heat exchanger are applied to the heater cores 60s and 60h, but may be applied to other heat exchangers such as an EGR cooler and an oil cooler.

  In each of the above embodiments, the valves Vs1, Vs2, Vh1, Vh2, Vs3, and Vh3 constituting the distribution device 40 are controlled to adjust the opening degree in a half-open state, but in a fully open state and a fully closed state You may make it abolish the opening degree adjustment in a half-open state by controlling to switch.

  -Although the water pump 10 of each said embodiment is an engine drive type which act | operates with the rotational drive force of an engine, the electric type which act | operates with an electric motor may be sufficient. In this case, the operation of the water pump 10 is stopped during the period from t1 to t2 in FIG. 2 when the cylinder temperature Ts rises to the lower limit temperature Tlow, and the temperature rise of the cylinder part Es during the warm-up operation is promoted. Good.

  DESCRIPTION OF SYMBOLS 20 ... Cylinder path | route, 30 ... Head path | route, 40 ... Distribution apparatus (distribution control apparatus, introduction control apparatus), 41, 41s, 41h ... Thermostat, 42, 42s, 42h ... Bypass path, 60 ... EGR cooler (heat exchanger) , 60s ... heater core (cylinder heat exchanger), 60h ... (head heat exchanger), 70 ... ECU (distribution control device, introduction control device), Es ... cylinder portion, Eh ... head portion, Tlow ... lower limit temperature, High ... upper limit temperature, Vs1, Vs2, Vh1, Vh2, Vs3, Vh3 ... electromagnetic valve, Vs3 ... cylinder side three-way valve, Vh3 ... head side three-way valve.

Claims (5)

A cylinder path for circulating cooling water for cooling the engine to the cylinder part of the engine, and a head path for circulating cooling water to the head part of the engine;
A heat exchanger that introduces cooling water flowing through the cylinder path or the head path, and exchanges heat between the introduced cooling water and a predetermined fluid, and
Applied to a vehicle configured to be able to adjust the distribution ratio of cooling water to the cylinder path and the head path;
A distribution control device that controls the distribution ratio so that the temperature of the cylinder portion is higher than the temperature of the head portion during warm-up operation of the engine;
When the temperature of the cylinder part rises to a predetermined lower limit temperature, cooling water is introduced into the heat exchanger from the cylinder path, and then when the temperature of the head part rises to the lower limit temperature, An introduction control device for controlling a cooling water introduction path so as to introduce cooling water from the head path to the heat exchanger;
An engine cooling water circulation system comprising:   The introduction control device is a period until the temperature of the cylinder part rises to an upper limit temperature set higher than the lower limit temperature even after the temperature of the head part rises to the lower limit temperature. The engine cooling water circulation system according to claim 1, wherein control is performed to allow cooling water to be introduced from the cylinder path to the heat exchanger. The introduction control device includes:
An electromagnetic valve for controlling a circulation amount of cooling water to the heat exchanger or the radiator;
A bypass path for bypassing the electromagnetic valve and circulating cooling water;
A thermostat that opens the valve when the cooling water temperature rises to the relief temperature set higher than the lower limit temperature, and distributes the cooling water to the bypass path;
The engine coolant circulation system according to claim 1, wherein the engine coolant circulation system is provided.   The heat exchanger includes a cylinder heat exchanger that introduces cooling water from the cylinder path and a head heat exchanger that introduces cooling water from the head path. The engine coolant circulation system according to any one of claims 1 to 3. The introduction control device includes:
A cylinder side three-way valve that opens and closes a path that circulates from the cylinder path to bypass the heat exchanger, and opens and closes a path that circulates from the cylinder path to the heat exchanger;
It has at least one of a head side three-way valve that opens and closes a path that circulates through the heat exchanger from the head path and opens and closes a path that circulates from the head path to the heat exchanger. The engine coolant circulation system according to any one of claims 1 to 4.

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