JP5633199B2

JP5633199B2 - Internal combustion engine cooling system

Info

Publication number: JP5633199B2
Application number: JP2010130035A
Authority: JP
Inventors: 内田　光宣; 光宣内田; 基正飯塚; 梯　伸治; 伸治梯; 道夫西川
Original assignee: Denso Corp; Nippon Soken Inc
Current assignee: Denso Corp; Soken Inc
Priority date: 2010-06-07
Filing date: 2010-06-07
Publication date: 2014-12-03
Anticipated expiration: 2030-06-07
Also published as: JP2011256736A

Description

本発明は、内燃機関の冷却システムに関するものである。 The present invention relates to a cooling system for an internal combustion engine.

内燃機関の冷却システムとして、シリンダヘッド内のヘッド側流路とシリンダブロック内のブロック側流路とを互いに独立させて設けた内燃機関の冷却システムが特許文献１に記載されている。 As a cooling system for an internal combustion engine, Patent Document 1 discloses a cooling system for an internal combustion engine in which a head side flow path in a cylinder head and a block side flow path in a cylinder block are provided independently of each other.

この特許文献１に記載の冷却システムは、１つのラジエータと内燃機関との間で冷却水が循環する冷却水回路が形成され、上流側分岐点で冷却水がヘッド側流路とブロック側流路の両流路に分配され、下流側合流点で両流路から流出の冷却水が合流し、合流後の冷却水がラジエータもしくはヒータコアに流入する構成となっている。さらに、この冷却システムでは、ブロック側流路の下流側に設けた流量制御弁によって、ヘッド側流路とブロック側流路への分配量を調整できるようになっている。 In the cooling system described in Patent Document 1, a cooling water circuit in which cooling water circulates between one radiator and the internal combustion engine is formed, and the cooling water flows at the upstream branch point at the head side flow path and the block side flow path. The cooling water flowing out from both flow paths joins at the downstream junction, and the combined cooling water flows into the radiator or the heater core. Furthermore, in this cooling system, the distribution amount to the head side flow path and the block side flow path can be adjusted by a flow rate control valve provided on the downstream side of the block side flow path.

特開２００５−３６７３１号公報JP 2005-36731 A

ところで、近年では、車両に搭載される内燃機関（エンジン）に対して、要求される出力を確保しつつ、従来よりも小型化させたいという要望がある。これを実現するために、圧縮比を上げたり、過給機付き内燃機関では過給圧を上げたりすると、ノッキングが生じる恐れがあるので、耐ノッキング性能を向上させる必要があり、耐ノッキング性能を向上させるために、シリンダヘッドを積極的に冷却することが考えられる。 By the way, in recent years, there is a demand for reducing the size of an internal combustion engine (engine) mounted on a vehicle while ensuring the required output. In order to achieve this, knocking may occur if the compression ratio is increased or the boost pressure is increased in an internal combustion engine with a supercharger. Therefore, it is necessary to improve the anti-knocking performance. In order to improve, it is conceivable to actively cool the cylinder head.

一方、シリンダブロックについては内燃機関内部のフリクション増加を抑制するために、所定温度以上に維持する必要がある。 On the other hand, the cylinder block must be maintained at a predetermined temperature or higher in order to suppress an increase in friction inside the internal combustion engine.

そこで、上述の冷却システムを用いた場合では、ヘッド側流路に大流量の冷却水を分配し、ブロック側流路に小流量の冷却水を分配することで、シリンダヘッドのみを積極的に冷却することが考えられる。この場合、ヘッド側流路から流出の冷却水は低温となり、ブロック側流路から流出の冷却水は高温となる。 Therefore, when the above-described cooling system is used, only the cylinder head is actively cooled by distributing a large flow rate of cooling water to the head-side flow channel and distributing a small flow rate of cooling water to the block-side flow channel. It is possible to do. In this case, the cooling water flowing out from the head side flow path becomes a low temperature, and the cooling water flowing out from the block side flow path becomes a high temperature.

しかし、上述の冷却システムでは、暖房時に、ヘッド側流路からの冷却水とブロック側流路からの冷却水とが合流して、ヒータコアに流入することとなる。このとき、ヘッド側流路からの低温大流量の冷却水と、ブロック側流路からの高温小流量の冷却水とを混合させてしまうと、混合後の冷却水温度は、ブロック側流路からの冷却水よりもヘッド側流路からの冷却水温度に近づいてしまう。 However, in the above-described cooling system, at the time of heating, the cooling water from the head side flow path and the cooling water from the block side flow path merge and flow into the heater core. At this time, if the low-temperature and large-flow rate cooling water from the head-side flow channel and the high-temperature and small-flow rate cooling water from the block-side flow channel are mixed, the mixed cooling water temperature is reduced from the block-side flow channel. The temperature of the cooling water from the head-side channel is closer to that of the cooling water.

このため、ヘッド側流路から流出の冷却水温度を低くしようとすると、ヒータコア流入の冷却水温度も連動して低くなるので、暖房性能を維持できる温度までしか、ヘッド流出の冷却水温度を下げることができず、シリンダヘッドの冷却性能をより高めることは困難である。 For this reason, if the cooling water temperature flowing out from the head-side flow path is lowered, the cooling water temperature flowing into the heater core also decreases in conjunction with it, so the cooling water temperature flowing out of the head is lowered only to a temperature at which heating performance can be maintained. It is difficult to improve the cooling performance of the cylinder head.

本発明は上記点に鑑みて、ヘッド側流路とブロック側流路に対して冷却水を分配する構成と比較して、暖房性能を維持しつつ、ヘッド側流路流出の冷却水温度をより低くできる内燃機関の冷却システムを提供することを目的とする。 In view of the above points, the present invention has a higher cooling water temperature at the head side channel outflow while maintaining the heating performance as compared with the configuration in which the cooling water is distributed to the head side channel and the block side channel. It is an object of the present invention to provide a cooling system for an internal combustion engine that can be lowered.

上記目的を達成するため、請求項１に記載の発明は、
シリンダヘッド（３）内に形成され、冷却水が流れるヘッド側流路（１１）と、
シリンダブロック（４）内に形成され、ヘッド側流路（１１）と独立して冷却水が流れるブロック側流路（２１）と、
ヘッド側流路（１１）から流出の冷却水を放熱させ、放熱後の冷却水をヘッド側流路（１１）に流入させる第１放熱器（１２）と、
第１放熱器（１２）と独立して冷却水が流れるとともに、ブロック側流路（２１）から流出の冷却水を放熱させ、放熱後の冷却水をブロック側流路に流入させる第２放熱器（２２）と、
ヘッド側流路（１１）と第１放熱器（１２）との間で冷却水が循環する第１冷却水回路（１０）と、
ブロック側流路（２１）と第２放熱器（２２）との間で冷却水が循環する第２冷却水回路（２０）と、
第１冷却水回路（１０）に設けられ、ヘッド側流路（１１）と第１放熱器（１２）との間で冷却水を循環させる第１循環手段（１５）と、
第２冷却水回路（２０）に設けられ、ブロック側流路（２１）と第２放熱器（２２）との間で冷却水を循環させる第２循環手段（２５）と、
冷却水との熱交換によって車室内に向かう送風空気を加熱する加熱用熱交換器（３１）と、
第１冷却水回路（１０）から加熱用熱交換器（３１）に流入する冷却水経路と、第２冷却水回路（２０）から加熱用熱交換器（３１）に流入する冷却水経路との一方もしくはその両方のいずれかに切り替える機能を有する第１経路切替手段（３２）と、
加熱用熱交換器（３１）から第１冷却水回路（１０）に冷却水が戻る冷却水経路と、加熱用熱交換器（３１）から第２冷却水回路（２０）に冷却水が戻る冷却水経路との一方もしくはその両方のいずれかに切り替える機能を有する第２経路切替手段（３３）と、
第１、第２経路切替手段（３２、３３）を制御する制御手段（４０）とを備え、
制御手段（４０）は、
加熱用熱交換器（３１）に流出入する冷却水経路が、第１冷却水回路（１０）から加熱用熱交換器（３１）に流入して第１冷却水回路（１０）に冷却水が戻る冷却水経路となるように、第１、第２経路切替手段（３２、３３）を制御する第１の制御と、
加熱用熱交換器（３１）に流出入する冷却水経路が、第２冷却水回路（２０）から加熱用熱交換器（３１）に流入して第２冷却水回路（２０）に冷却水が戻る冷却水経路となるように、第１、第２経路切替手段（３２、３３）を制御する第２の制御と、
第１、第２冷却水回路（１０、２０）の両方から冷却水が合流して加熱用熱交換器（３１）に流入した後、加熱用熱交換器（３１）流出の冷却水が分流して第１、第２冷却水回路（１０、２０）に流入するように、第１、第２経路切替手段（３２、３３）を制御する第３の制御とを実行することを特徴とする。 In order to achieve the above object, the invention described in claim 1
A head-side channel (11) formed in the cylinder head (3) and through which cooling water flows;
A block-side channel (21) formed in the cylinder block (4) and through which cooling water flows independently of the head-side channel (11);
A first radiator (12) for radiating the cooling water flowing out from the head side flow path (11) and allowing the cooling water after heat radiation to flow into the head side flow path (11);
A second radiator that allows cooling water to flow independently of the first radiator (12), dissipates the cooling water flowing out from the block-side flow path (21), and allows the cooling water after heat radiation to flow into the block-side flow path. (22)
A first cooling water circuit (10) in which cooling water circulates between the head side flow path (11) and the first radiator (12);
A second cooling water circuit (20) in which cooling water circulates between the block-side flow path (21) and the second radiator (22);
A first circulation means (15) provided in the first cooling water circuit (10) for circulating the cooling water between the head side flow path (11) and the first radiator (12);
A second circulation means (25) provided in the second cooling water circuit (20) for circulating the cooling water between the block-side flow path (21) and the second radiator (22);
A heating heat exchanger (31) for heating the air blown toward the vehicle interior by heat exchange with the cooling water;
A cooling water path flowing from the first cooling water circuit (10) into the heating heat exchanger (31) and a cooling water path flowing from the second cooling water circuit (20) into the heating heat exchanger (31) A first path switching means (32) having a function of switching to one or both,
Cooling water path for returning cooling water from the heating heat exchanger (31) to the first cooling water circuit (10), and cooling for returning cooling water from the heating heat exchanger (31) to the second cooling water circuit (20) A second path switching means (33) having a function of switching to one or both of the water path,
Control means (40) for controlling the first and second path switching means (32, 33),
The control means (40)
A cooling water path flowing into and out of the heating heat exchanger (31) flows into the heating heat exchanger (31) from the first cooling water circuit (10) and cooling water enters the first cooling water circuit (10). A first control for controlling the first and second path switching means (32, 33) so as to return to the cooling water path;
A cooling water path flowing into and out of the heating heat exchanger (31) flows into the heating heat exchanger (31) from the second cooling water circuit (20) and cooling water enters the second cooling water circuit (20). A second control for controlling the first and second path switching means (32, 33) so as to return to the cooling water path;
After the cooling water merges from both the first and second cooling water circuits (10, 20) and flows into the heating heat exchanger (31), the cooling water flowing out of the heating heat exchanger (31) is divided. And third control for controlling the first and second path switching means (32, 33) so as to flow into the first and second cooling water circuits (10, 20) .

これによると、ヘッド側流路と第１放熱器との間で冷却水が循環する冷却水回路と、ブロック側流路と第２放熱器との間で冷却水が循環する冷却水回路とを独立して形成しているので、ヘッド側流出の冷却水温度を低く、ブロック側流出の冷却水温度を高くするという冷却水の温度制御が可能である。 According to this, the cooling water circuit in which the cooling water circulates between the head side flow path and the first radiator, and the cooling water circuit in which the cooling water circulates between the block side flow path and the second radiator. Since it is formed independently, it is possible to control the temperature of the cooling water by lowering the cooling water temperature at the head side outflow and increasing the cooling water temperature at the block side outflow.

さらに、加熱用熱交換器に流出入する冷却水の経路を切り替える第１、第２経路切替手段を設けているので、ヘッド側流路から流出の冷却水の温度をブロック側流路から流出の冷却水の温度よりも低くする場合には、ブロック側流路から流出の冷却水を加熱用熱交換器に流入させるとともに、ブロック側流路から流出の冷却水の温度を暖房性能維持に必要な温度とすることで、暖房性能を維持できる。 Furthermore, first switching the path of the cooling water flowing into and out the heating heat exchanger, since the provided second path switching means, from the head-side passage of the outflow temperature of the cooling water flowing out of the block-side passage When the temperature is lower than the temperature of the cooling water, the cooling water flowing out from the block-side flow path is allowed to flow into the heat exchanger for heating, and the temperature of the cooling water flowing out from the block-side flow path is necessary for maintaining the heating performance. Heating performance can be maintained by setting the temperature.

よって、本発明によれば、ヘッド側流路とブロック側流路に対して冷却水を分配する構成と比較して、暖房性能を維持しつつ、ヘッド側流路から流出の冷却水の温度をより低くすることが可能となる。 Therefore, according to the present invention, compared with the configuration in which the cooling water is distributed to the head side channel and the block side channel, the temperature of the cooling water flowing out from the head side channel is maintained while maintaining the heating performance. It becomes possible to make it lower.

また、請求項１に記載の発明では、第１経路切替手段（３２）は、第１冷却水回路（１０）から加熱用熱交換器（３１）に冷却水が流入する冷却水経路と第２冷却水回路（２０）から加熱用熱交換器（３１）に冷却水が流入する冷却水経路との一方もしくはその両方に切り替え可能な機能を有し、第２経路切替手段（３３）は、加熱用熱交換器（３１）から第１冷却水回路（１０）に冷却水が戻る冷却水経路と、加熱用熱交換器（３１）から第２冷却水回路（２０）に冷却水が戻る冷却水経路との一方もしくはその両方のいずれかに切り替える機能を有している。 Further, the invention described in claim 1, the first path switching means (32), the cooling water passage and a second cooling water to the heating heat exchanger (31) from the first coolant circuit (10) flows The second path switching means (33) has a function capable of switching to one or both of the cooling water path through which the cooling water flows from the cooling water circuit (20) to the heating heat exchanger (31). The cooling water path from which the cooling water returns from the heat exchanger (31) to the first cooling water circuit (10), and the cooling water from which the cooling water returns from the heating heat exchanger (31) to the second cooling water circuit (20) It has a function of switching to either one or both of the routes.

この場合、第１冷却水回路（１０）から流出の冷却水と第２冷却水回路（２０）から流出の冷却水との流量割合を、第１、第２循環手段によって調整したり、経路切替手段に流量割合調整機能を持たせて、この経路切替手段によって調整したりすることがより好ましい。これにより、加熱用熱交換器に流入する冷却水温度を制御でき、加熱用熱交換器で加熱後の空気温度を制御することも可能となる。 In this case, the flow rate ratio between the cooling water flowing out from the first cooling water circuit (10) and the cooling water flowing out from the second cooling water circuit (20) is adjusted by the first and second circulation means, or the path is switched. More preferably, the means is provided with a flow rate ratio adjusting function and adjusted by this path switching means. Thereby, the temperature of the cooling water flowing into the heating heat exchanger can be controlled, and the air temperature after heating can be controlled by the heating heat exchanger.

請求項２に記載の発明は、請求項１に記載の発明において、制御手段（４０）は、少なくとも、ヘッド側流路（１１）内もしくはヘッド側流路（１１）から流出の冷却水の温度を検出する第１水温センサ（４１）と、ブロック側流路（２１）内もしくはブロック側流路（２１）から流出の冷却水の温度を検出する第２水温センサ（４２）の検出結果に基づき、第２水温センサ（４２）で検出した冷却水温度が、所定温度よりも低く、かつ、第１水温センサ（４１）で検出した冷却水温度よりも低い場合に、第１の制御を実行し、第２水温センサ（４２）で検出した冷却水温度が、所定温度よりも低く、かつ、第１水温センサ（４１）で検出した冷却水温度よりも高い場合に、第２の制御を実行し、第１、第２の制御を実行した後において、内燃機関（２）の負荷が予め定められた所定値よりも低いと判定した場合に、第３の制御を実行することを特徴とする。請求項１に記載の発明において、このような構成を採用することができる。
また、請求項３に記載の発明のように、請求項１に記載の発明において、制御手段（４０）は、少なくとも、ヘッド側流路（１１）内もしくはヘッド側流路（１１）から流出の冷却水の温度を検出する第１水温センサ（４１）と、ブロック側流路（２１）内もしくはブロック側流路（２１）から流出の冷却水の温度を検出する第２水温センサ（４２）の検出結果に基づき、内燃機関（２）の暖機時には、第２水温センサ（４２）で検出した冷却水温度が第１水温センサ（４１）で検出した冷却水温度よりも低い場合に、第１の制御を実行し、第２水温センサ（４２）で検出した冷却水温度が第１水温センサ（４１）で検出した冷却水温度よりも高い場合に、第２の制御を実行し、内燃機関（２）の暖機後には、内燃機関（２）の負荷が予め定められた所定値よりも高いと判定した場合に、第２の制御を実行し、内燃機関（２）の負荷が予め定められた所定値よりも低いと判定した場合に、第３の制御を実行するようにすることもできる。 According to a second aspect of the present invention, in the first aspect of the present invention, the control means (40) includes at least the temperature of the cooling water flowing out from the head side flow path (11) or from the head side flow path (11). Based on the detection result of the first water temperature sensor (41) for detecting the temperature of the coolant flowing out from the block side channel (21) or from the block side channel (21). The first control is executed when the coolant temperature detected by the second coolant temperature sensor (42) is lower than the predetermined temperature and lower than the coolant temperature detected by the first coolant temperature sensor (41). The second control is executed when the coolant temperature detected by the second coolant temperature sensor (42) is lower than the predetermined temperature and higher than the coolant temperature detected by the first coolant temperature sensor (41). After executing the first and second controls, When the load of the engine (2) is determined to be lower than a predetermined prescribed value, and executes the third control. In the invention described in claim 1 , such a configuration can be adopted.
Further, as in the invention according to claim 3, in the invention according to claim 1, the control means (40) is configured to flow at least in the head side channel (11) or from the head side channel (11). A first water temperature sensor (41) for detecting the temperature of the cooling water, and a second water temperature sensor (42) for detecting the temperature of the cooling water flowing out from the block side channel (21) or from the block side channel (21). Based on the detection result, when the internal combustion engine (2) is warmed up, the first coolant temperature is detected when the coolant temperature detected by the second coolant temperature sensor (42) is lower than the coolant temperature detected by the first coolant temperature sensor (41). When the cooling water temperature detected by the second water temperature sensor (42) is higher than the cooling water temperature detected by the first water temperature sensor (41), the second control is executed and the internal combustion engine ( After the warm-up of 2), the load on the internal combustion engine (2) is predetermined. When it is determined that the load is higher than the predetermined value, the second control is executed. When it is determined that the load of the internal combustion engine (2) is lower than the predetermined value, the third control is executed. You can also do it.

また、請求項４に記載の発明は、請求項２または３に記載の発明において、制御手段（４０）は、少なくとも、第１水温センサ（４１）と第２水温センサ（４２）の検出結果に基づいて、第１の制御と、第２の制御と、第３の制御とを実行するとともに、第１循環手段（１５）による冷却水循環量および第２循環手段（２５）による冷却水循環量の制御を行うことを特徴とする。 According to a fourth aspect of the present invention, in the invention according to the second or third aspect , the control means (40) at least detects the detection results of the first water temperature sensor (41) and the second water temperature sensor (42). Based on this, the first control, the second control, and the third control are executed, and the cooling water circulation amount by the first circulation means (15) and the cooling water circulation amount by the second circulation means (25) are controlled. It is characterized by performing .

なお、この欄および特許請求の範囲で記載した各手段の括弧内の符号は、後述する実施形態に記載の具体的手段との対応関係を示すものである。 In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

本発明の第１実施形態における内燃機関の冷却システムの全体構成を示す模式図である。It is a mimetic diagram showing the whole cooling system composition of an internal-combustion engine in a 1st embodiment of the present invention. 図１中の第１経路切替弁３２の縦断面図である。It is a longitudinal cross-sectional view of the 1st path | route switching valve 32 in FIG. 図２の第１経路切替弁３２による冷却水経路の各切替状態を示す図である。It is a figure which shows each switching state of the cooling water path | route by the 1st path | route switching valve 32 of FIG. 各エンジン運転状態でのヘッド側流路１１、ブロック側流路２１の冷却水温度および冷却水流量を示す図である。It is a figure which shows the cooling water temperature and the cooling water flow rate of the head side flow path 11 and the block side flow path 21 in each engine operation state. 始動・暖機前半時かつ空調装置作動時での冷却水の循環経路を示す図である。It is a figure which shows the circulation path | route of the cooling water at the time of starting and warming-up first half time and air-conditioner action | operation. 暖機後半時かつ空調装置作動時での冷却水の循環経路を示す図である。It is a figure which shows the circulation path | route of the cooling water at the time of warm-up second half and the time of air-conditioner operation | movement. 高負荷運転時かつ空調装置作動時での冷却水の循環経路を示す図である。It is a figure which shows the circulation path of the cooling water at the time of high load driving | operating and air-conditioner operation | movement. 低負荷運転時かつ空調装置作動時での冷却水の循環経路を示す図である。It is a figure which shows the circulation path of the cooling water at the time of low load driving | running | working and an air conditioner action | operation. 空調装置停止時での冷却水の循環経路を示す図である。It is a figure which shows the circulation path of the cooling water at the time of an air-conditioner stop.

以下、本発明の実施形態について図に基づいて説明する。なお、各図面において、互いに同一もしくは均等である部分には、説明の簡略化を図るべく、図中、同一符号を付してある。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, parts that are the same or equivalent to each other are given the same reference numerals in the drawings for the sake of simplicity.

（第１実施形態）
図１に、本実施形態における内燃機関の冷却システムの全体構成を示す。本実施形態の内燃機関の冷却システム１は、内燃機関（エンジン）および走行用電動モータの双方から直接駆動力を得て走行可能なパラレル型のハイブリッド車に搭載されるものである。 (First embodiment)
FIG. 1 shows an overall configuration of a cooling system for an internal combustion engine in the present embodiment. The internal combustion engine cooling system 1 according to this embodiment is mounted on a parallel hybrid vehicle that can travel by directly obtaining driving force from both the internal combustion engine (engine) and the traveling electric motor.

図１に示すように、内燃機関の冷却システム１は、エンジン２のシリンダヘッド３内に形成されたヘッド側流路１１と、エンジン２のシリンダブロック４内に形成されたブロック側流路２１と、ヘッド側流路１１から流出の冷却水を放熱させる第１ラジエータ１２と、ブロック側流路２１から流出の冷却水を放熱させる第２ラジエータ２２とを備えている。そして、ヘッド側流路１１と第１ラジエータ１２との間で冷却水が循環する第１冷却水回路１０と、ブロック側流路２１と第２ラジエータ２２との間で冷却水が循環する第２冷却水回路２０とが独立して形成されている。 As shown in FIG. 1, the internal combustion engine cooling system 1 includes a head-side passage 11 formed in the cylinder head 3 of the engine 2, and a block-side passage 21 formed in the cylinder block 4 of the engine 2. The first radiator 12 for radiating the cooling water flowing out from the head side flow path 11 and the second radiator 22 for radiating the cooling water flowing out from the block side flow path 21 are provided. Then, the first cooling water circuit 10 in which the cooling water circulates between the head side flow path 11 and the first radiator 12, and the second cooling water circulates between the block side flow path 21 and the second radiator 22. The cooling water circuit 20 is formed independently.

エンジン２のシリンダヘッド３は、ピストンが往復運動するシリンダボア（円柱状の穴）の上死点側の開口部を閉塞して燃焼室を構成するブロック体である。シリンダブロック４は、シリンダボアを構成するブロック体である。 The cylinder head 3 of the engine 2 is a block body that constitutes a combustion chamber by closing the top dead center side opening of a cylinder bore (columnar hole) in which a piston reciprocates. The cylinder block 4 is a block body constituting a cylinder bore.

ヘッド側流路１１およびブロック側流路２１は、シリンダの周囲近傍に形成されたウォータジャケットと呼ばれる冷却水流路であり、それぞれ、シリンダヘッド３およびシリンダブロック４を冷却する冷却水が流れる。冷却水は、水もしくは添加成分を含む水である。 The head side channel 11 and the block side channel 21 are cooling water channels called water jackets formed in the vicinity of the periphery of the cylinder, and cooling water for cooling the cylinder head 3 and the cylinder block 4 flows, respectively. The cooling water is water or water containing additive components.

シリンダヘッド３では、シリンダヘッド３に設けられたヘッド側冷却水入口３ａから冷却水が流入し、ヘッド側流路１１を冷却水が流れる。そして、ヘッド側流路１１通過後の冷却水がシリンダヘッド３に設けられたヘッド側冷却水出口３ｂから流出する。 In the cylinder head 3, cooling water flows from the head side cooling water inlet 3 a provided in the cylinder head 3, and the cooling water flows through the head side flow path 11. Then, the cooling water after passing through the head-side flow path 11 flows out from the head-side cooling water outlet 3 b provided in the cylinder head 3.

一方、シリンダブロック４では、シリンダブロック４に設けられたブロック側冷却水入口４ａから冷却水が流入し、ブロック側流路２１を冷却水が流れる。そして、ブロック側流路２１通過後の冷却水がシリンダブロック４に設けられたブロック側冷却水出口４ｂから流出する。 On the other hand, in the cylinder block 4, the cooling water flows from the block side cooling water inlet 4 a provided in the cylinder block 4, and the cooling water flows through the block side flow path 21. Then, the cooling water after passing through the block side flow passage 21 flows out from the block side cooling water outlet 4 b provided in the cylinder block 4.

このように、ヘッド側流路１１およびブロック側流路２１の一方を流れた冷却水は、他方に流入することなく、各冷却水出口３ｂ、４ｂからエンジン２の外部に流出する構成となっている。すなわち、ヘッド側流路１１とブロック側流路２１とを冷却水が独立して流れる構成となっている。 Thus, the cooling water that has flowed through one of the head-side flow path 11 and the block-side flow path 21 flows out of the engine 2 from the respective cooling water outlets 3b and 4b without flowing into the other. Yes. That is, the cooling water flows independently through the head side channel 11 and the block side channel 21.

第１、第２ラジエータ１２、２２は、冷却水と空気との熱交換によって、冷却水を放熱させる放熱器である。第１ラジエータ１２の方が第２ラジエータ２２よりも冷却性能（放熱性能）が高く、第１ラジエータ１２の方が第２ラジエータ２２よりも放熱後の冷却水の温度を低くできる。具体的には、冷却水と空気とが熱交換する熱交換コア部の面積が、第１ラジエータ１２の方が第２ラジエータ２２よりも広くなっている。なお、熱交換コア部の面積が同じでも、第１ラジエータ１２に送風するファンの送風能力を、第２ラジエータ２２よりも高くする等により、第１ラジエータ１２の冷却性能を高くしても良い。 The first and second radiators 12 and 22 are radiators that radiate cooling water by heat exchange between the cooling water and air. The first radiator 12 has higher cooling performance (heat radiation performance) than the second radiator 22, and the first radiator 12 can lower the temperature of the cooling water after heat radiation than the second radiator 22. Specifically, the area of the heat exchange core portion where heat is exchanged between the cooling water and air is larger in the first radiator 12 than in the second radiator 22. Even if the area of the heat exchange core portion is the same, the cooling performance of the first radiator 12 may be increased by making the blowing capacity of the fan that blows air to the first radiator 12 higher than that of the second radiator 22.

第１冷却水回路１０には、第１ラジエータ１２を迂回して冷却水が流れる第１バイパス通路１３が設けられている。この第１バイパス通路１３とヘッド側流路１１との間で冷却水が循環する、いわゆる内部循環回路が形成される。同様に、第２冷却水回路２０には、第２ラジエータ２２を迂回して冷却水が流れる第２バイパス通路２３が設けられている。この第２バイパス通路２３とブロック側流路２１との間で冷却水が循環する、いわゆる内部循環回路が形成される。 The first cooling water circuit 10 is provided with a first bypass passage 13 through which the cooling water flows around the first radiator 12. A so-called internal circulation circuit is formed in which cooling water circulates between the first bypass passage 13 and the head-side passage 11. Similarly, the second cooling water circuit 20 is provided with a second bypass passage 23 in which the cooling water flows around the second radiator 22. A so-called internal circulation circuit is formed in which cooling water circulates between the second bypass passage 23 and the block-side flow passage 21.

第１、第２バイパス通路１３、２３の下流側端部には、それぞれ、第１、第２サーモスタット（Ｔ／Ｓ）１４、２４が設けられている。この第１、第２サーモスタット１４、２４は、冷却水の温度に応じて、ラジエータ１２、２２側へ流れる冷却水の流量を変更する流量変更手段である。ラジエータ１２、２２側を開弁する温度は、第１サーモスタット１４の方が第２サーモスタット２４よりも低くなっている。 First and second thermostats (T / S) 14 and 24 are provided at downstream ends of the first and second bypass passages 13 and 23, respectively. The first and second thermostats 14 and 24 are flow rate changing means for changing the flow rate of the cooling water flowing toward the radiators 12 and 22 according to the temperature of the cooling water. The temperature at which the radiators 12 and 22 are opened is lower in the first thermostat 14 than in the second thermostat 24.

第１、第２冷却回路１０、２０には、それぞれ、冷却水の循環手段および流量調整手段としての第１、第２電動ウォータポンプ１５、２５が設けられている。第１、第２電動ウォータポンプは、電動モータで駆動するものであり、後述するエンジンＥＣＵ４０からの制御信号によって、回転数（冷却水流量）が制御される。これにより、第１、第２冷却水回路の冷却水循環量が制御される。 The first and second cooling circuits 10 and 20 are provided with first and second electric water pumps 15 and 25 as cooling water circulation means and flow rate adjustment means, respectively. The first and second electric water pumps are driven by an electric motor, and the rotation speed (cooling water flow rate) is controlled by a control signal from an engine ECU 40 described later. Thereby, the cooling water circulation amount of the first and second cooling water circuits is controlled.

第１電動ウォータポンプ１５は、第１サーモスタット１４とヘッド側冷却水入口３ａとの間に設けられており、第２電動ウォータポンプ２５は、第２サーモスタット２４とブロック側冷却水入口４ａとの間に設けられている。 The first electric water pump 15 is provided between the first thermostat 14 and the head side cooling water inlet 3a, and the second electric water pump 25 is provided between the second thermostat 24 and the block side cooling water inlet 4a. Is provided.

また、第１冷却水回路１０のヘッド側流路１１の出口側と、第２冷却水回路２０のブロック側流路２１の出口側との両方に、各冷却水回路１０、２０から１つのヒータコア３１へ冷却水が至り、再び各冷却水回路１０、２０に冷却水が戻るヒータコア回路３０が接続されている。ちなみに、ヒータコア３１は、冷却水との熱交換によって車室内に向かう送風空気を加熱する加熱用熱交換器である。 Further, one heater core from each of the cooling water circuits 10 and 20 is provided on both the outlet side of the head side flow path 11 of the first cooling water circuit 10 and the outlet side of the block side flow path 21 of the second cooling water circuit 20. A heater core circuit 30 is connected to the cooling water that reaches the cooling water circuit 31 and returns to the cooling water circuits 10 and 20 again. Incidentally, the heater core 31 is a heat exchanger for heating that heats the air blown toward the vehicle interior by heat exchange with cooling water.

ヒータコア回路３０を具体的に説明する。第１冷却水回路１０のヘッド側冷却水出口３ｂの下流側に、ヘッド側流路１１から流出の冷却水をヒータコア３１に流入させるための第１分岐部１６と、ヒータコア３１通過後の冷却水を第１冷却水回路１０に戻すための第１合流部１７とが設けられている。同様に、第２冷却水回路２０のブロック側冷却水出口４ｂの下流側に、ブロック側流路２１から流出の冷却水をヒータコア３１に流入させるための第２分岐部２６と、ヒータコア３１通過後の冷却水を第２冷却水回路２０に戻すための第２合流部２７とが設けられている。 The heater core circuit 30 will be specifically described. A first branch part 16 for allowing cooling water flowing out from the head side flow path 11 to flow into the heater core 31 downstream of the head side cooling water outlet 3b of the first cooling water circuit 10, and cooling water after passing through the heater core 31 Is provided to the first cooling water circuit 10. Similarly, on the downstream side of the block-side cooling water outlet 4 b of the second cooling water circuit 20, a second branch portion 26 for allowing the cooling water flowing out from the block-side flow path 21 to flow into the heater core 31, and after passing through the heater core 31. And a second merging portion 27 for returning the cooling water to the second cooling water circuit 20.

そして、ヒータコア３１の上流側に、第１分岐部１６に連なる冷却水通路と、第２分岐部２６に連なる冷却水通路とが合流する第３合流部が設けられており、この第３合流部に第１経路切替弁３２が配置されている。また、ヒータコア３１の下流側には、第１合流部１７に連なる冷却水通路と、第２合流部２７に連なる冷却水通路とに分岐する第３分岐部が設けられており、この第３分岐部に第２経路切替弁３３が配置されている。 A third merging portion where the cooling water passage continuing to the first branching portion 16 and the cooling water passage continuing to the second branching portion 26 merge is provided on the upstream side of the heater core 31, and this third merging portion. The first path switching valve 32 is disposed at the end. Further, on the downstream side of the heater core 31, there is provided a third branch portion that branches into a cooling water passage continuing to the first joining portion 17 and a cooling water passage continuing to the second joining portion 27. The second path switching valve 33 is disposed in the section.

第１、第２経路切替弁３２、３３は、ヒータコア３１に流出入する冷却水の経路を切り替える経路切替手段であり、第１冷却水回路１０からヒータコア３１に流入して第１冷却水回路１０に冷却水が戻る冷却水経路と、第２冷却水回路１０からヒータコア３１に流入して第２冷却水回路２０に冷却水が戻る冷却水経路との一方もしくはその両方のいずれかに切り替える。 The first and second path switching valves 32 and 33 are path switching means for switching the path of the cooling water flowing into and out of the heater core 31. The first and second path switching valves 32 and 33 flow into the heater core 31 from the first cooling water circuit 10 and enter the first cooling water circuit 10. The cooling water path is returned to the cooling water path and the cooling water path flowing from the second cooling water circuit 10 into the heater core 31 and returning to the second cooling water circuit 20 is switched to one or both.

第１経路切替弁３２は、第１冷却水回路１０からヒータコア３１に流入する冷却水経路と、第２冷却水回路１０からヒータコア３１に流入する冷却水経路との一方もしくはその両方のいずれかに切り替える機能を有するものである。第１経路切替弁３２は、第１、第２冷却水回路１０、２０からの冷却水を合流させてヒータコア３１に流入させる場合に、第１、第２冷却水回路１０、２０の一方から他方への冷却水の流入を防止する機能を有している。また、第１経路切替弁３２は、空調ＯＦＦ時にヒータコア３１での不要な放熱を避けるために、閉弁可能な構造となっており、ヒータコア回路３０の循環を停止可能な機能も有している。 The first path switching valve 32 is provided in one or both of a cooling water path flowing from the first cooling water circuit 10 to the heater core 31 and a cooling water path flowing from the second cooling water circuit 10 to the heater core 31. It has a switching function. When the cooling water from the first and second cooling water circuits 10 and 20 is merged and flows into the heater core 31, the first path switching valve 32 is switched from one of the first and second cooling water circuits 10 and 20 to the other. It has a function to prevent the cooling water from flowing into the. Further, the first path switching valve 32 has a structure that can be closed in order to avoid unnecessary heat dissipation in the heater core 31 when the air conditioning is OFF, and has a function that can stop the circulation of the heater core circuit 30. .

第１経路切替弁３２としては、具体的には、図２に示す構造のものが採用可能である。ここで、図２に、第１経路切替弁３２の縦断面図を示す。また、図３に、図２の第１経路切替弁３２による冷却水経路の各切替状態を示す。 As the first path switching valve 32, specifically, the structure shown in FIG. 2 can be adopted. Here, FIG. 2 shows a longitudinal sectional view of the first path switching valve 32. FIG. 3 shows each switching state of the cooling water path by the first path switching valve 32 of FIG.

図２に示す第１経路切替弁３２は、第１冷却水回路１０側に接続される入口側の冷却水通路３２１と、第２冷却水回路２０側に接続される入口側の冷却水通路３２２と、ヒータコア３１側に接続される出口側の冷却水通路３２３と、入口側の冷却水通路３２１、３２２の合流部に設けられた切替ドア３２４、３２５とを備えている。この切替ドア３２４、３２５は、２枚の板状ドアで構成されており、２枚の板状ドアのそれぞれが一端を軸として独立して回動可能なバタフライ構造となっている。 The first path switching valve 32 shown in FIG. 2 includes an inlet-side cooling water passage 321 connected to the first cooling water circuit 10 side and an inlet-side cooling water passage 322 connected to the second cooling water circuit 20 side. And an outlet side cooling water passage 323 connected to the heater core 31 side, and switching doors 324 and 325 provided at the junction of the inlet side cooling water passages 321 and 322. The switching doors 324 and 325 are composed of two plate-like doors, and each of the two plate-like doors has a butterfly structure that can rotate independently about one end as an axis.

そして、この第１経路切替弁３２では、２枚の切替ドア３２４、３２５が同じ位置に移動して、図３（ａ）、（ｂ）に示すように、２つの入口側の冷却水通路３２１、３２２の一方のみを開いた状態としたり、図３（ｃ）に示すように、両方を開いた状態としたりすることができる。また、図３（ｄ）に示すように、２枚の切替ドア３２４、３２５が異なる位置に移動して、２つの入口側の冷却水通路３２１、３２２の両方を閉じた状態とすることができる。 In the first path switching valve 32, the two switching doors 324 and 325 move to the same position, and as shown in FIGS. 3A and 3B, the two cooling water passages 321 on the inlet side. 322, only one of them can be opened, or both can be opened as shown in FIG. Further, as shown in FIG. 3D, the two switching doors 324 and 325 can move to different positions, and both the two inlet side cooling water passages 321 and 322 can be closed. .

なお、本実施形態では、第１経路切替弁３２として、図２に示す構造のものを採用しているが、本実施形態と同様の機能を有していれば、一般的なロータリバルブ等の他の構造のものを採用しても良い。 In the present embodiment, the structure shown in FIG. 2 is adopted as the first path switching valve 32. However, if the first path switching valve 32 has the same function as the present embodiment, a general rotary valve or the like can be used. Other structures may be employed.

第２経路切替弁３３は、ヒータコア３１から第１冷却水回路１０に冷却水が戻る冷却水経路と、ヒータコア３１から第２冷却水回路２０に冷却水が戻る冷却水経路との一方もしくはその両方のいずれかに切り替える機能を有するものである。第２経路切替弁３３としては、このような機能を有するものであれば、一般的な切替弁が採用可能である。 The second path switching valve 33 is one or both of a cooling water path for returning cooling water from the heater core 31 to the first cooling water circuit 10 and a cooling water path for returning cooling water from the heater core 31 to the second cooling water circuit 20. It has the function to switch to either. As the second path switching valve 33, a general switching valve can be adopted as long as it has such a function.

また、第２経路切替弁３３の下流側であって第１冷却水回路１０の第１合流部１７よりも上流側の冷却水通路および第２経路切替弁３３の下流側であって第２冷却水回路２０の第２合流部２７よりも上流側の冷却水通路には、それぞれ、逆流を防止するための逆止弁３４、３５が設けられている。 In addition, downstream of the second path switching valve 33 and upstream of the first merging portion 17 of the first cooling water circuit 10 and downstream of the second path switching valve 33 and second cooling. Check valves 34 and 35 for preventing backflow are respectively provided in the cooling water passages upstream of the second junction 27 of the water circuit 20.

冷却システム１は、エンジン制御装置（以下、エンジンＥＣＵという）４０を備えている。エンジンＥＣＵ４０は、入力側に接続された各種センサからの入力信号に基づいて、出力側に接続された冷却システム１の各種機器の作動を制御する制御手段である。なお、このエンジンＥＣＵ４０は、図示しない燃料噴射装置等の各種機器の作動も制御するが、この点については従来と同様であるため説明を省略する。 The cooling system 1 includes an engine control device (hereinafter referred to as an engine ECU) 40. The engine ECU 40 is a control unit that controls the operation of various devices of the cooling system 1 connected to the output side based on input signals from various sensors connected to the input side. The engine ECU 40 also controls the operation of various devices such as a fuel injection device (not shown), but since this is the same as the conventional one, the description thereof is omitted.

具体的には、エンジンＥＣＵ４０の入力側に、エンジン運転状態を検知する各種センサとして、ヘッド側流路１１から流出した冷却水の温度を検出する第１水温センサ４１、ブロック側流路２１から流出した冷却水の温度を検出する第２水温センサ４２、エンジン回転数を検出する回転数センサ４３およびエンジンの吸入空気量を検出する吸気量センサ４４等が接続されている。なお、他のセンサとしては、アクセルペダルの踏み込み量を検出するセンサや、車速を検出するセンサ等が挙げられる。 Specifically, on the input side of the engine ECU 40, as various sensors for detecting the engine operating state, the first water temperature sensor 41 for detecting the temperature of the cooling water flowing out from the head side flow path 11 and the flow from the block side flow path 21 are used. A second water temperature sensor 42 for detecting the temperature of the cooled cooling water, a rotation speed sensor 43 for detecting the engine rotation speed, an intake air amount sensor 44 for detecting the intake air amount of the engine, and the like are connected. Other sensors include a sensor that detects the amount of depression of an accelerator pedal, a sensor that detects the vehicle speed, and the like.

一方、エンジンＥＣＵ４０の出力側には、冷却システム１の第１、第２電動ウォータポンプ１５、２５および第１、第２経路切替弁３２、３３が接続されている。したがって、エンジンＥＣＵ４０は、エンジン冷却制御プログラムを実行することにより、エンジン運転状態に応じて、第１、第２電動ウォータポンプ１５、２５および第１、第２経路切替弁３２、３３を制御する。 On the other hand, the first and second electric water pumps 15 and 25 of the cooling system 1 and the first and second path switching valves 32 and 33 are connected to the output side of the engine ECU 40. Therefore, the engine ECU 40 controls the first and second electric water pumps 15 and 25 and the first and second path switching valves 32 and 33 according to the engine operating state by executing the engine cooling control program.

また、エンジンＥＣＵ４０は、図示しない空調制御装置（以下、エアコンＥＣＵという）と電気的に接続されており、エアコンＥＣＵと通信可能に構成されている。これにより、エンジンＥＣＵ４０は、空調装置の作動・停止等の運転状態に関する情報が入力される。 The engine ECU 40 is electrically connected to an air conditioning control device (hereinafter referred to as an air conditioner ECU) (not shown), and is configured to be communicable with the air conditioner ECU. As a result, the engine ECU 40 receives information related to the operation state such as operation / stop of the air conditioner.

次に、エンジンＥＣＵが実行するエンジンの冷却制御について説明する。 Next, engine cooling control executed by the engine ECU will be described.

エンジンＥＣＵ４０は、エンジンの冷却制御プログラムを実行することにより、エンジンの運転状態および空調装置の運転状態に応じて、第１、第２経路切替弁３２、３３および第１、第２電動ウォータポンプ１５、２５を制御する。 The engine ECU 40 executes the engine cooling control program, so that the first and second path switching valves 32 and 33 and the first and second electric water pumps 15 correspond to the operating state of the engine and the operating state of the air conditioner. , 25 are controlled.

ここで、図４に、各エンジン運転状態でのヘッド側流路１１、ブロック側流路２１の冷却水温度および冷却水流量を示す。また、図５〜９に、各エンジン運転状態での冷却水の循環経路を示す。 Here, FIG. 4 shows the cooling water temperature and the cooling water flow rate of the head side flow path 11 and the block side flow path 21 in each engine operating state. Moreover, the circulation path of the cooling water in each engine operation state is shown in FIGS.

〈始動・暖機前半時かつ空調Ｏｎ時〉
図５は、始動・暖機前半時かつ空調装置作動（空調ＯＮ）時での冷却水の循環経路を示している。ここでいう始動、暖機前半時とは、ブロック側流路２１の冷却水温度が、所定温度よりも低く、かつ、ヘッド側流路１１の冷却水温度よりも低い場合である。したがって、エンジンＥＣＵ４０は、第２水温センサ４２で検出した冷却水温度が、所定温度よりも低く、かつ、第１水温センサ４１で検出した冷却水温度よりも低い場合に、始動・暖機前半時であると判定する。 <Starting / Warming first half hour and air conditioning On>
FIG. 5 shows a cooling water circulation path during the first half of start-up / warm-up and when the air conditioner is activated (air conditioning ON). The start-up and the first half of warm-up here refer to the case where the cooling water temperature in the block-side channel 21 is lower than a predetermined temperature and lower than the cooling water temperature in the head-side channel 11. Therefore, when the coolant temperature detected by the second water temperature sensor 42 is lower than the predetermined temperature and lower than the coolant temperature detected by the first water temperature sensor 41, the engine ECU 40 starts and warms up in the first half It is determined that

始動、暖機前半時では、ヘッド側流路１１、ブロック側流路２１から流出の冷却水は、どちらもサーモスタット１４、２４の開弁温度まで水温が上昇していないため、第１、第２ラジエータ１２、２２を経由せずに、それぞれ、内部循環回路を通って第１、第２電動ウォータポンプ１５、２５の上流側に流入する。このとき、ヘッド側流路１１とブロック側流路２１とは、冷却水が独立して流れる構成であるため、燃焼室からの伝熱により、ヘッド側流路１１内の冷却水の方がブロック側流路２１内の冷却水よりも水温上昇が早い。 In the first half of the start-up and warm-up, the cooling water flowing out from the head-side channel 11 and the block-side channel 21 has not risen to the valve opening temperature of the thermostats 14, 24. Instead of passing through the radiators 12 and 22, they flow through the internal circulation circuit to the upstream side of the first and second electric water pumps 15 and 25, respectively. At this time, since the head-side flow path 11 and the block-side flow path 21 are configured so that the cooling water flows independently, the cooling water in the head-side flow path 11 is blocked by heat transfer from the combustion chamber. The water temperature rises faster than the cooling water in the side channel 21.

そこで、始動、暖機前半時かつ空調ＯＮ時では、エンジンＥＣＵ４０は、ヒータコア３１に流出入する冷却水経路が、第１冷却水回路１０からヒータコア３１に流入して第１冷却水回路１０に冷却水が戻る冷却水経路となるように、第１、第２経路切替弁３２、３３を制御する。 Therefore, at the time of start-up, the first half of warm-up, and the air conditioning ON, the engine ECU 40 cools the cooling water path flowing into and out of the heater core 31 from the first cooling water circuit 10 to the heater core 31 and cooling to the first cooling water circuit 10. The first and second path switching valves 32 and 33 are controlled so that the cooling water path returns to the water.

このとき、図４に示すように、エンジンＥＣＵ４０は、ヘッド側流路１１を流れる冷却水の流量が、エンジン暖機を促進しつつ、空調（暖房）のために要求される必要最低限の流量（空調要求流量）となるように、第１ウォータポンプ１５の回転数（冷却水流量）を制御する。ちなみに、空調要求流量は、ヒータコア３１の暖房能力を確保するために、冷却水温度に応じてヒータコア３１に必要な冷却水流量が定められるが、図４では、便宜上、空調要求流量を一定量としている。 At this time, as shown in FIG. 4, the engine ECU 40 has a minimum flow rate required for air conditioning (heating) while the flow rate of the cooling water flowing through the head side flow path 11 promotes engine warm-up. The number of rotations (cooling water flow rate) of the first water pump 15 is controlled so as to be (air conditioning required flow rate). Incidentally, the required air conditioning flow rate is determined in accordance with the cooling water temperature in order to ensure the heating capacity of the heater core 31, but in FIG. Yes.

一方、ブロック側流路２１の冷却水流量については、エンジン暖機を促進できる流量であれば良いので、エンジンＥＣＵ４０は、ブロック側流路２１の冷却水流量が極小流量となるように、第２ウォータポンプ２５の回転数（冷却水流量）を制御する。なお、第２ウォータポンプ２５を停止させても良い。 On the other hand, the coolant flow rate in the block-side flow path 21 may be any flow rate that can promote engine warm-up, so the engine ECU 40 sets the second flow rate so that the coolant flow rate in the block-side flow path 21 becomes a minimum flow rate. The rotational speed (cooling water flow rate) of the water pump 25 is controlled. Note that the second water pump 25 may be stopped.

これにより、始動、暖機前半時では、水温上昇が速いヘッド側流路１１から流出の冷却水のみがヒータコア３１に流入するので、即効暖房が可能となる。 As a result, during the start-up and the first half of warm-up, only the cooling water flowing out from the head-side flow path 11 where the water temperature rises quickly flows into the heater core 31, so that immediate heating is possible.

また、本実施形態では、ヘッド側流路１１とブロック側流路２１とを、それぞれ、独立して冷却水が内部循環するので、ヘッド側流路１１の方がブロック側流路２１よりも水温上昇が早く、すなわち、シリンダヘッド３の方がシリンダブロック４よりも温度上昇が早い。 In the present embodiment, since the cooling water circulates independently through the head-side channel 11 and the block-side channel 21, the head-side channel 11 has a higher water temperature than the block-side channel 21. The rise is faster, that is, the temperature of the cylinder head 3 is faster than that of the cylinder block 4.

これに対して、ヘッド側流路１１とブロック側流路２１とを冷却水が独立して内部循環せず、ヘッド側流路１１とブロック側流路２１との上流側で冷却水が分流し、ヘッド側流路１１とブロック側流路２１の下流側で冷却水が合流する場合では、ヘッド側流路１１、ブロック側流路２１から流出の冷却水が混合するので、ヘッド側流路１１とブロック側流路２１での水温上昇は同程度となってしまう。 On the other hand, the cooling water does not circulate independently through the head-side flow path 11 and the block-side flow path 21, and the cooling water is divided upstream of the head-side flow path 11 and the block-side flow path 21. When the cooling water merges downstream of the head side flow path 11 and the block side flow path 21, the cooling water flowing out from the head side flow path 11 and the block side flow path 21 is mixed. And the water temperature rise in the block side flow path 21 will be comparable.

このため、通常、シリンダヘッド３の温度が低いほど、燃料噴射量を多くする燃料噴射量制御がされるところ、本実施形態によれば、ヘッド側流路１１とブロック側流路２１とを独立して冷却水が内部循環しない場合と比較して、シリンダヘッド３の温度上昇が早いので、燃料噴射量の早期減量による燃費向上が可能となる。 For this reason, normally, the fuel injection amount control is performed such that the fuel injection amount is increased as the temperature of the cylinder head 3 is lower. According to the present embodiment, the head side channel 11 and the block side channel 21 are made independent. Since the temperature rise of the cylinder head 3 is faster than when the cooling water does not circulate internally, fuel consumption can be improved by reducing the fuel injection amount early.

〈暖機後半時かつ空調ＯＮ時〉
図６は、暖機後半時かつ空調装置作動時での冷却水の循環経路を示している。ここでいう暖機後半時とは、ブロック側流路２１の冷却水温度が、所定温度よりも低く、かつ、ヘッド側流路１１の冷却水温度よりも高い場合である。したがって、エンジンＥＣＵ４０は、第２水温センサ４２で検出した冷却水温度が、所定温度よりも低く、かつ、第１水温センサ４１で検出した冷却水温度よりも高い場合に、暖機後半時であると判定する。 <Warm-up late and air-conditioning ON>
FIG. 6 shows a cooling water circulation path in the second half of warm-up and when the air conditioner is activated. The latter half of the warm-up here is a case where the cooling water temperature of the block-side flow path 21 is lower than a predetermined temperature and higher than the cooling water temperature of the head-side flow path 11. Therefore, the engine ECU 40 is in the second half of the warm-up when the coolant temperature detected by the second coolant temperature sensor 42 is lower than the predetermined temperature and higher than the coolant temperature detected by the first coolant temperature sensor 41. Is determined.

暖機後半時では、ヘッド側流路１１、ブロック側流路２１から流出の冷却水が、どちらも第１サーモスタット１４の開弁温度以上であって第２サーモスタット２４の開弁温度以下の温度まで水温が上昇することで、図６に示すように、第１冷却水回路１０では、第１サーモスタット１４が開弁して、第１ラジエータ１２に冷却水が流入するが、第２冷却水回路２０では、第２サーモスタット２４が開弁せず、第２ラジエータ２２に冷却水が循環しない内部循環が継続される。 In the latter half of the warm-up period, the cooling water flowing out from the head side channel 11 and the block side channel 21 is both higher than the valve opening temperature of the first thermostat 14 and lower than the valve opening temperature of the second thermostat 24. As the water temperature rises, as shown in FIG. 6, in the first cooling water circuit 10, the first thermostat 14 opens and the cooling water flows into the first radiator 12, but the second cooling water circuit 20 Then, the second thermostat 24 does not open, and the internal circulation in which the cooling water does not circulate through the second radiator 22 is continued.

このため、図４に示すように、ヘッド側流路１１から流出の冷却水温度はほぼ一定になるが、ブロック側流路２１から流出の冷却水温度は、時間経過に伴い上昇し続けるので、ブロック側流路２１から流出の冷却水の温度が、ヘッド側流路１１から流出の冷却水の温度よりも高くなる。 For this reason, as shown in FIG. 4, the cooling water temperature flowing out from the head-side flow path 11 becomes substantially constant, but the cooling water temperature flowing out from the block-side flow path 21 continues to rise as time passes. The temperature of the cooling water flowing out from the block side flow path 21 becomes higher than the temperature of the cooling water flowing out from the head side flow path 11.

そこで、暖機後半時かつ空調ＯＮ時では、エンジンＥＣＵ４０は、ヒータコア３１に流出入する冷却水経路が、第２冷却水回路２０からヒータコア３１に流入して第２冷却水回路２０に冷却水が戻る冷却水経路となるように、第１、第２経路切替弁３２、３３を制御する。 Therefore, during the second half of warm-up and when the air conditioner is ON, the engine ECU 40 causes the cooling water path that flows into and out of the heater core 31 to flow into the heater core 31 from the second cooling water circuit 20 and the cooling water flows into the second cooling water circuit 20. The first and second path switching valves 32 and 33 are controlled so as to return to the cooling water path.

また、図４に示すように、エンジンＥＣＵ４０は、ブロック側流路２１を流れる冷却水の流量が、エンジン暖機を促進しつつ、空調のために要求される必要最低限の空調要求流量となるように、第２ウォータポンプ２５の回転数（冷却水流量）を制御する。一方、ヘッド側流路１１を流れる冷却水流量は、シリンダヘッド３の所望の冷却を行えれば良いので、シリンダヘッド３の冷却に必要な流量となるように、第１ウォータポンプ１５の回転数（冷却水流量）を制御する。 Further, as shown in FIG. 4, in the engine ECU 40, the flow rate of the cooling water flowing through the block-side flow path 21 becomes the minimum required air conditioning flow rate required for air conditioning while promoting engine warm-up. Thus, the rotation speed (cooling water flow rate) of the second water pump 25 is controlled. On the other hand, the flow rate of the cooling water flowing through the head-side flow path 11 only needs to be able to cool the cylinder head 3, so the rotational speed of the first water pump 15 is set to a flow rate necessary for cooling the cylinder head 3. (Cooling water flow rate) is controlled.

〈高負荷運転時かつ空調ＯＮ時〉
図７は、高負荷運転時かつ空調装置作動（空調ＯＮ）時での冷却水の循環経路を示している。ここでいう高負荷運転時は、エンジンＥＣＵ４０がエンジン回転数や空気吸入量等の運転状態に関する情報に基づいて導かれるエンジン負荷が予め定められた所定値よりも高いと判定した場合である。 <During high load operation and air conditioning ON>
FIG. 7 shows a cooling water circulation path during high load operation and when the air conditioner is activated (air conditioning ON). The high-load operation here is a case where the engine ECU 40 determines that the engine load derived based on information about the operation state such as the engine speed and the air intake amount is higher than a predetermined value.

この暖機後高負荷時かつ空調ＯＮ時では、エンジンＥＣＵ４０は、ヒータコア３１に流出入する冷却水経路が、第２冷却水回路２０からヒータコア３１に流入して第２冷却水回路２０に冷却水が戻る冷却水経路となるように、第１、第２経路切替弁３２、３３を制御する。 At the time of high load after warm-up and when the air conditioning is ON, the engine ECU 40 causes the cooling water path flowing into and out of the heater core 31 to flow into the heater core 31 from the second cooling water circuit 20 and to the second cooling water circuit 20. The first and second path switching valves 32 and 33 are controlled so that the cooling water path returns.

また、図４に示すように、エンジンＥＣＵ４０は、シリンダヘッド３の冷却に必要な流量となるように、第１ウォータポンプ１５の回転数（冷却水流量）を制御する。具体的には、シリンダヘッド３を積極的に冷却してノッキングを抑制するために、ヘッド側流路１１から流出の冷却水温度が、例えば、４０〜６０℃となる冷却水流量とする。このときの冷却水温度は空調に必要な最低温度（空調要求温度）よりも低い温度であり、このときの冷却水流量は空調要求流量よりも大流量である。 As shown in FIG. 4, the engine ECU 40 controls the rotation speed (cooling water flow rate) of the first water pump 15 so that the flow rate is necessary for cooling the cylinder head 3. Specifically, in order to actively cool the cylinder head 3 and suppress knocking, the cooling water temperature flowing out from the head side flow path 11 is set to a cooling water flow rate of 40 to 60 ° C., for example. The cooling water temperature at this time is lower than the minimum temperature (required air conditioning temperature) necessary for air conditioning, and the cooling water flow rate at this time is larger than the required air conditioning flow rate.

また、図４に示すように、エンジンＥＣＵ４０は、ブロック側流路２１を流れる冷却水の流量が、シリンダヘッド３の冷却に必要な流量、かつ、空調要求流量以上となるように、第２ウォータポンプ２５の回転数（冷却水流量）を制御する。具体的には、エンジン内部のフリクション増大を抑制しつつ、暖房性能を維持できるように、ブロック側流路２１から流出の冷却水温度が、所定温度以上、例えば、８０〜９０℃となる冷却水流量とする。 Further, as shown in FIG. 4, the engine ECU 40 sets the second water so that the flow rate of the cooling water flowing through the block-side flow path 21 is equal to or higher than the flow rate required for cooling the cylinder head 3 and the required air conditioning flow rate. The rotation speed (cooling water flow rate) of the pump 25 is controlled. Specifically, the cooling water temperature at which the cooling water flowing out from the block-side flow path 21 is equal to or higher than a predetermined temperature, for example, 80 to 90 ° C., so that the heating performance can be maintained while suppressing an increase in friction inside the engine. The flow rate.

これにより、第１冷却水回路１０においては、第１ラジエータ１２で第２ラジエータ２２よりも低温にされた冷却水が、ヘッド側流路１１に大流量流入するので、高負荷運転時のノッキング発生を効果的に抑制できる。 As a result, in the first cooling water circuit 10, the cooling water having a temperature lower than that of the second radiator 22 by the first radiator 12 flows into the head-side channel 11, so that knocking occurs during high load operation. Can be effectively suppressed.

一方、第２冷却水回路２０においては、第１ラジエータ１１流出の冷却水よりも高温である第２ラジエータ２２流出の冷却水が、シリンダブロック４を過冷却しない程度の流量にて、ブロック側流路２１に流入するので、フリクション増大を効果的に抑制できる。 On the other hand, in the second cooling water circuit 20, the cooling water flowing out of the second radiator 22, which is higher in temperature than the cooling water flowing out of the first radiator 11, has a flow rate that blocks the side flow of the cylinder block 4. Since it flows into the path 21, an increase in friction can be effectively suppressed.

また、ヒータコア３１においては、ヘッド側流路１１から流出の冷却水をヒータコア３１に大流量流入させると、暖房性能が維持できなくなってしまうため、ヘッド側流路１１から流出の冷却水ではなく、ブロック側流路２１から流出の冷却水をヒータコア３１に流入させることにより、暖房性能維持が可能となる。 Further, in the heater core 31, if the cooling water flowing out from the head side flow path 11 is flowed into the heater core 31 at a large flow rate, the heating performance cannot be maintained. Heating performance can be maintained by allowing the cooling water flowing out from the block-side channel 21 to flow into the heater core 31.

〈低負荷運転時かつ空調ＯＮ時〉
図８は、低負荷運転時かつ空調装置作動（空調ＯＮ）時での冷却水の循環経路を示している。ここでいう低負荷運転時は、エンジンＥＣＵ４０がエンジン回転数や空気吸入量等の運転状態に関する情報に基づいて導かれるエンジン負荷が予め定められた所定値よりも低いと判定した場合である。 <Low load operation and air conditioning ON>
FIG. 8 shows the circulation path of the cooling water during low load operation and when the air conditioner is activated (air conditioning ON). Here, the low-load operation is a case where the engine ECU 40 determines that the engine load derived based on information about the operation state such as the engine speed and the air intake amount is lower than a predetermined value.

低負荷運転時かつ空調ＯＮ時では、エンジンＥＣＵ４０は、第１、第２冷却水回路１０、２０の両方から冷却水が合流してヒータコア３１に流入した後、ヒータコア３１流出の冷却水が分流して第１、第２冷却水回路１０、２０に流入するように、第１、第２経路切替弁３２、３３を制御する。 During low load operation and air conditioning ON, the engine ECU 40 causes the coolant from both the first and second coolant circuits 10 and 20 to merge and flow into the heater core 31, and then the coolant that flows out of the heater core 31 is diverted. The first and second path switching valves 32 and 33 are controlled so as to flow into the first and second cooling water circuits 10 and 20.

また、図４に示すように、エンジンＥＣＵ４０は、ヘッド側流路１１の冷却水流量およびブロック側流路２１の冷却水流量が、シリンダヘッド３およびシリンダブロック４の冷却に必要な最低流量となるように、第１、第２ウォータポンプ１５、２５の回転数を制御する。 Further, as shown in FIG. 4, in the engine ECU 40, the cooling water flow rate of the head side flow path 11 and the cooling water flow rate of the block side flow path 21 are the minimum flow rates necessary for cooling the cylinder head 3 and the cylinder block 4. Thus, the rotation speed of the 1st, 2nd water pumps 15 and 25 is controlled.

ここで、ヘッド側流路１１の冷却水流量を低流量とすると、ヘッド側流路１１から流出の冷却水温度が高負荷運転時と比較して高温となるので、ヘッド側流路１１から流出の冷却水を暖房熱源として利用することが可能となる。 Here, if the cooling water flow rate of the head side flow path 11 is low, the cooling water temperature flowing out from the head side flow path 11 becomes higher than that at the time of high load operation. This cooling water can be used as a heating heat source.

しかし、低負荷運転時に、ヘッド側流路１１のみならずブロック側流路２１も低流量制御を実施した場合、ヘッド側流路１１とブロック側流路２１のどちらか一方から流出の冷却水のみをヒータコア３１に流入させると、ヒータコアに流入する冷却水の流量が空調要求流量を満たさない。 However, when low flow control is performed not only on the head-side flow path 11 but also on the block-side flow path 21 during low-load operation, only cooling water flowing out from either the head-side flow path 11 or the block-side flow path 21 is used. When flowing into the heater core 31, the flow rate of the cooling water flowing into the heater core does not satisfy the required air conditioning flow rate.

そこで、この場合では、ヘッド側流路１１から流出の冷却水とブロック側流路２１から流出の冷却水とを合流させることにより、ヘッド側流路１１およびブロック側流路２１の冷却水流量を極力抑えつつ、空調要求流量以上の流量の冷却水をヒータコア３１へ導入することが可能となる。 Therefore, in this case, the cooling water flow rate of the head side flow channel 11 and the block side flow channel 21 is reduced by combining the cooling water flowing out from the head side flow channel 11 and the cooling water flowing out from the block side flow channel 21. It is possible to introduce cooling water having a flow rate higher than the required air conditioning flow rate into the heater core 31 while suppressing the pressure as much as possible.

なお、ブロック側流路２１の冷却水流量が空調要求流量以上の場合、高負荷運転時のように、ブロック側流路２１からの冷却水のみをヒータコア３１に流入させても良い。 In addition, when the cooling water flow rate of the block side flow path 21 is more than the air conditioning request flow rate, only the cooling water from the block side flow path 21 may be allowed to flow into the heater core 31 as in a high load operation.

〈空調ＯＦＦ時〉
図８は、空調装置停止（空調ＯＦＦ）時での冷却水の循環経路を示している。 <When air conditioning is off>
FIG. 8 shows a cooling water circulation path when the air conditioner is stopped (air conditioning OFF).

空調ＯＦＦ時の場合、ヒータコア３１へ冷却水を導入する必要がなく、シリンダヘッド３およびシリンダブロック４に対して必要な冷却を行えば良い。 When the air conditioning is OFF, it is not necessary to introduce cooling water into the heater core 31, and the cylinder head 3 and the cylinder block 4 may be cooled as necessary.

したがって、エンジンＥＣＵ４０は、ヒータコア回路３０の冷却水循環が停止するように、第１、第２経路切替弁３２、３３を制御するとともに、ヘッド側流路１１、ブロック側流路２１の冷却水流量が、シリンダヘッド３およびシリンダブロック４の冷却に必要な冷却水量となるように、第１、第２ウォータポンプ１５、２５の回転数を制御する。 Therefore, the engine ECU 40 controls the first and second path switching valves 32 and 33 so that the cooling water circulation of the heater core circuit 30 is stopped, and the cooling water flow rates of the head side flow path 11 and the block side flow path 21 are increased. The rotational speeds of the first and second water pumps 15 and 25 are controlled so that the cooling water amount required for cooling the cylinder head 3 and the cylinder block 4 is obtained.

これにより、第１、第２冷却水回路１０、２０では、それぞれ、ヒータコア回路３０に冷却水が流入することなく、冷却水が循環する。 As a result, in the first and second cooling water circuits 10 and 20, the cooling water circulates without flowing into the heater core circuit 30.

次に、本実施形態の主な特徴について説明する。 Next, main features of the present embodiment will be described.

（１）本実施形態によると、ヘッド側流路１１と第１ラジエータ２１との間で冷却水が循環する第１冷却水回路１０と、ブロック側流路２１と第２ラジエータ２２との間で冷却水が循環する第２冷却水回路２０とを独立して形成しているので、高負荷運転時では、ヘッド側流路１１から流出の冷却水温度を低く、ブロック側流路２１から流出の冷却水温度を高くするという冷却水の温度制御が可能である。 (1) According to this embodiment, between the first cooling water circuit 10 in which the cooling water circulates between the head side flow path 11 and the first radiator 21, and between the block side flow path 21 and the second radiator 22. Since the second cooling water circuit 20 in which the cooling water circulates is formed independently, the cooling water temperature flowing out from the head side flow path 11 is low and the outflow from the block side flow path 21 during high load operation. It is possible to control the temperature of the cooling water by increasing the cooling water temperature.

さらに、本実施形態では、ヒータコア３１に流出入する冷却水の経路を切り替える第１、第２経路切替弁３２、３３を設けているので、ヘッド側流路１１から流出の冷却水の温度が暖房性能を維持できない温度まで低くなっても、ブロック側流路２１から流出の冷却水をヒータコア３１に流入させるとともに、ブロック側流路２１から流出の冷却水の温度を暖房性能維持に必要な温度とすることで、暖房性能を維持できる。 Further, in the present embodiment, the first and second path switching valves 32 and 33 that switch the path of the cooling water flowing into and out of the heater core 31 are provided. Even if the temperature is lowered to a temperature at which the performance cannot be maintained, the cooling water flowing out from the block-side flow channel 21 flows into the heater core 31, and the temperature of the cooling water flowing out from the block-side flow channel 21 is set to a temperature necessary for maintaining the heating performance. By doing so, the heating performance can be maintained.

よって、本実施形態によれば、ヘッド側流路とブロック側流路に対して冷却水を分配供給する構成の特許文献１に記載の冷却システムと比較して、暖房性能を維持しつつ、ヘッド側流路１１から流出の冷却水の温度をより低くすることが可能となる。 Therefore, according to the present embodiment, the head performance is maintained while maintaining the heating performance as compared with the cooling system described in Patent Document 1 configured to distribute and supply the cooling water to the head-side flow path and the block-side flow path. It becomes possible to make the temperature of the cooling water flowing out from the side flow path 11 lower.

（２）特許文献１に記載のように、ヘッド側流路とブロック側流路の入口側で、ラジエータ放熱後の冷却水をヘッド側流路とブロック側流路に分配供給する構成の冷却システムでは、ヘッド側流路とブロック側流路の入口側の冷却水温度は同じとなってしまう。 (2) A cooling system configured to distribute and supply cooling water after heat radiation from the radiator to the head side channel and the block side channel on the inlet side of the head side channel and the block side channel as described in Patent Document 1. Then, the coolant temperature on the inlet side of the head side channel and the block side channel becomes the same.

このため、ヘッド側流路から流出の冷却水温度を比較的低温とし、ブロック側流路から流出の冷却水温度を比較的高温となるように、ヘッド側流路とブロック側流路の分配流量を調整すると、ブロック側流路の入口側温度と出口側温度の差が大きくなり、シリンダブロックに熱歪みが発生する恐れがある。 For this reason, the distribution flow rate of the head side channel and the block side channel is set so that the cooling water temperature flowing out from the head side channel is relatively low and the cooling water temperature flowing out from the block side channel is relatively high. If is adjusted, the difference between the inlet-side temperature and the outlet-side temperature of the block-side flow path increases, and there is a risk that thermal distortion will occur in the cylinder block.

これに対して、本実施形態では、第１、第２冷却水回路１０、２０を互いに独立して形成しているので、ブロック側流路２１に流入する冷却水の温度を、ヘッド側流路１１に流入する冷却水の温度と独立して制御できる。このため、本実施形態によれば、特許文献１に記載の冷却システムと比較して、ブロック側流路２１に流入する冷却水温度を高くでき、ブロック側流路２１の入口側と出口側の温度差を低減できる。よって、シリンダブロック４に発生する熱歪みを抑制できる。 On the other hand, in the present embodiment, the first and second cooling water circuits 10 and 20 are formed independently of each other, so that the temperature of the cooling water flowing into the block side flow path 21 is set to the head side flow path. 11 can be controlled independently of the temperature of the cooling water flowing into 11. For this reason, according to this embodiment, compared with the cooling system described in Patent Document 1, the temperature of the cooling water flowing into the block-side channel 21 can be increased, and the inlet side and the outlet side of the block-side channel 21 can be increased. The temperature difference can be reduced. Therefore, thermal distortion generated in the cylinder block 4 can be suppressed.

（第２実施形態）
第１実施形態では、高負荷運転時に、ヘッド側流路１１から流出の冷却水よりも高温であるブロック側流路２１から流出の冷却水のみをヒータコア３１に流入させたが、第１、第２経路切替弁３２、３３によって、ヘッド側流路１１から流出の冷却水とブロック側流路２１から流出の冷却水との両方をヒータコア３１に流入させるようにしても良い。 (Second Embodiment)
In the first embodiment, at the time of high load operation, only the cooling water that has flowed out from the block-side flow channel 21, which is higher in temperature than the cooling water that has flowed out from the head-side flow channel 11, flows into the heater core 31. Both the cooling water flowing out from the head side flow path 11 and the cooling water flowing out from the block side flow path 21 may be caused to flow into the heater core 31 by the two-path switching valves 32 and 33.

この場合、ヘッド側流路１１から流出の冷却水とブロック側流路２１から流出の冷却水との流量割合を流量調整手段によって調整する。流量調整手段としては、第１、第２電動ウォータポンプ１５、２５を利用することができる。第１、第２ウォータポンプ１５、２５の流量制御によって、ヒータコア３１に流入する冷却水を任意の温度に調整することで、ヒータコア３１で加熱後の空気温度を制御することも可能となる。 In this case, the flow rate adjusting means adjusts the flow rate ratio between the cooling water flowing out from the head side flow path 11 and the cooling water flowing out from the block side flow path 21. As the flow rate adjusting means, the first and second electric water pumps 15 and 25 can be used. By adjusting the cooling water flowing into the heater core 31 to an arbitrary temperature by controlling the flow rates of the first and second water pumps 15 and 25, the air temperature after heating by the heater core 31 can be controlled.

なお、流量調整手段として第１、第２電動ウォータポンプ１５、２５を利用する代わりに、第１流路切替弁３２に流量調整機能を持たせても良い。この場合、第１流路切替弁３２を、第１冷却水回路１０側に連なる流路と第２冷却水回路２０側に連なる流路のそれぞれの開口面積が変化可能な構造とすれば良い。 Instead of using the first and second electric water pumps 15 and 25 as flow rate adjusting means, the first flow path switching valve 32 may have a flow rate adjusting function. In this case, the first flow path switching valve 32 may have a structure in which the respective opening areas of the flow path connected to the first cooling water circuit 10 side and the flow path connected to the second cooling water circuit 20 side can be changed.

また、高負荷運転時に限らず、低負荷運転時であっても、ヘッド側流路１１から流出の冷却水が低温であり、ブロック側流路から流出の冷却水が高温であれば、本実施形態と同様に、両方の冷却水の流量調整によって、ヒータコア３１に流入する冷却水の温度を調整しても良い。 Further, not only during high load operation but also during low load operation, if the cooling water flowing out from the head side flow path 11 is low temperature and the cooling water flowing out from the block side flow path is high temperature, this implementation Similarly to the embodiment, the temperature of the cooling water flowing into the heater core 31 may be adjusted by adjusting the flow rates of both cooling waters.

（他の実施形態）
（１）上述の実施形態では、第１冷却水回路１０の第１分岐部１６と第１合流部１７との間や、第２冷却水回路２０の第２分岐部２６と第２合流部２７との間は、常に、冷却水が流通可能であったため、各冷却水回路１０、２０からヒータコア３１に冷却水を導く際に、ヒータコア３１を迂回する冷却水流れが形成されてしまう。そこで、第１冷却水回路１０の第１分岐部１６と第１合流部１７との間や、第２冷却水回路２０の第２分岐部２６と第２合流部２７との間に、開閉弁等を設けることにより、ヒータコア３１に冷却水を導く際に、ヒータコア３１を迂回する冷却水流れが形成されないようにすることもできる。 (Other embodiments)
(1) In the above-described embodiment, between the first branch portion 16 and the first junction portion 17 of the first cooling water circuit 10 or the second branch portion 26 and the second junction portion 27 of the second cooling water circuit 20. Since the cooling water was always circulated between and, the cooling water flow bypassing the heater core 31 is formed when the cooling water is guided from the respective cooling water circuits 10 and 20 to the heater core 31. Therefore, an on-off valve is provided between the first branch portion 16 and the first junction portion 17 of the first cooling water circuit 10 and between the second branch portion 26 and the second junction portion 27 of the second cooling water circuit 20. For example, when the cooling water is guided to the heater core 31, a cooling water flow that bypasses the heater core 31 can be prevented from being formed.

（２）上述の実施形態では、経路切替手段として用いた第１、第２経路切替弁３２、３３は、第１冷却水回路１０からヒータコア３１に流入して第１冷却水回路１０に冷却水が戻る冷却水経路と、第２冷却水回路１０からヒータコア３１に流入して第２冷却水回路２０に冷却水が戻る冷却水経路との一方もしくはその両方のいずれかに切り替える構成であったが、一方のみに切り替える構成であっても良い。この場合、経路切替手段を、例えば、ヒータコア３１の上流側で第１分岐部１６、第２分岐部２６にそれぞれ連なる通路およびヒータコア３１の下流側で第１合流部１７、第２合流部２７にそれぞれ連なる通路の各通路に設置した開閉弁で構成しても良い。 (2) In the above-described embodiment, the first and second path switching valves 32 and 33 used as the path switching means flow into the heater core 31 from the first cooling water circuit 10 and enter the cooling water into the first cooling water circuit 10. The cooling water path returns to the cooling water path and the cooling water path flows into the heater core 31 from the second cooling water circuit 10 and returns to the second cooling water circuit 20. The configuration may be such that only one is switched. In this case, for example, the path switching means is connected to the first junction 16 and the second junction 27 on the downstream side of the heater core 31 and the passage connecting to the first branch 16 and the second branch 26 on the upstream side of the heater core 31. You may comprise with the on-off valve installed in each channel | path of the channel | path which each continues.

（３）上述の実施形態では、第１ラジエータ１２の方が第２ラジエータ２２よりも冷却性能（放熱性能）が高かったが、第１、第２ラジエータ１２、２２の放熱性能を同じとしても良い。この場合であっても、第１、第２冷却水回路１０、２０それぞれの冷却水流量の制御や、第１、第２サーモスタットの開弁設定温度によって、ヘッド側流路１１、ブロック側流路２１から流出の冷却水温度を異ならせることができる。 (3) In the above-described embodiment, the first radiator 12 has higher cooling performance (heat dissipation performance) than the second radiator 22, but the first and second radiators 12 and 22 may have the same heat dissipation performance. . Even in this case, the head-side flow path 11 and the block-side flow path are controlled according to the control of the cooling water flow rates of the first and second cooling water circuits 10 and 20 and the valve opening set temperatures of the first and second thermostats. The cooling water temperature flowing out from 21 can be varied.

（４）上述の実施形態では、エンジンＥＣＵ４０とエアコンＥＣＵとを別々の電子制御装置として構成したが、これらを１つの電子制御装置として構成しても良い。また、上述の実施形態のエンジンＥＣＵ４０を、燃料噴射制御を行う燃料噴射用と、エンジン冷却制御用のそれぞれの電子制御装置として構成しても良い。 (4) In the above-described embodiment, the engine ECU 40 and the air conditioner ECU are configured as separate electronic control devices. However, they may be configured as one electronic control device. Further, the engine ECU 40 of the above-described embodiment may be configured as an electronic control device for fuel injection for performing fuel injection control and for engine cooling control.

（５）上述の実施形態では、第１、第２水温センサ４１、４２を、それぞれ、エンジン２の各冷却水出口３ｂ、４ｂの近傍に設けて、ヘッド側流路１１、ブロック側流路２１から流出の冷却水温度を検出したが、エンジン２の内部に設けて、ヘッド側流路１１、ブロック側流路２１内を流れる冷却水の温度を検出しても良い。 (5) In the above-described embodiment, the first and second water temperature sensors 41 and 42 are provided in the vicinity of the cooling water outlets 3b and 4b of the engine 2, respectively. However, the temperature of the cooling water flowing in the head side flow path 11 and the block side flow path 21 may be detected by providing inside the engine 2.

（６）上述の実施形態では、第１、第２循環手段として、第１、第２電動ウォータポンプ１５、２５を採用したが、電動式ではなく、機械式のウォータポンプを採用しても良い。 (6) In the above-described embodiment, the first and second electric water pumps 15 and 25 are employed as the first and second circulation means, but a mechanical water pump may be employed instead of the electric one. .

（７）第１実施形態では、第１、第２経路切替弁３２、３３の切替制御を、エンジン運転状態に応じて行ったが、単に、第１、第２水温センサの検出結果に基づいて、第１、第２経路切替弁の切替制御を行っても良い。 (7) In the first embodiment, the switching control of the first and second path switching valves 32 and 33 is performed according to the engine operating state, but simply based on the detection results of the first and second water temperature sensors. The switching control of the first and second path switching valves may be performed.

（８）上述の各実施形態を実施可能な範囲で組み合わせても良い。 (8) You may combine each above-mentioned embodiment in the range which can be implemented.

２エンジン（内燃機関）
３シリンダヘッド
４シリンダブロック
１０第１冷却水回路
１１ヘッド側流路
１２第１ラジエータ（第１放熱器）
１５第１ウォータポンプ（第１循環手段）
２０第２冷却水回路
２１ブロック側流路
２２第２ラジエータ（第２放熱器）
２５第２ウォータポンプ（第２循環手段）
３１ヒータコア（加熱用熱交換器）
３２第１経路切替弁（経路切替手段）
３３第２経路切替弁（経路切替手段）
４０エンジンＥＣＵ（制御手段）
４１第１水温センサ
４２第２水温センサ
４３回転数センサ（運転状態検出センサ）
４４吸気量センサ（運転状態検出センサ） 2 Engine (Internal combustion engine)
3 Cylinder head 4 Cylinder block 10 1st cooling water circuit 11 Head side flow path 12 1st radiator (1st heat radiator)
15 1st water pump (1st circulation means)
20 Second cooling water circuit 21 Block side flow path 22 Second radiator (second radiator)
25 Second water pump (second circulation means)
31 Heater core (heat exchanger for heating)
32 1st path switching valve (path switching means)
33 Second path switching valve (path switching means)
40 Engine ECU (control means)
41 1st water temperature sensor 42 2nd water temperature sensor 43 Rotational speed sensor (operation state detection sensor)
44 Intake sensor (operating state detection sensor)

Claims

A head-side flow path (11) formed in the cylinder head (3) of the internal combustion engine (2) and through which cooling water flows;
A block side flow path (21) formed in the cylinder block (4) of the internal combustion engine (2), through which cooling water flows independently of the head side flow path (11);
A first radiator (12) for dissipating the cooling water flowing out from the head-side flow path (11) and allowing the cooling water after heat dissipation to flow into the head-side flow path (11);
The cooling water flows independently of the first radiator (12), the cooling water flowing out from the block-side channel (21) is radiated, and the radiated cooling water flows into the block-side channel. 2 radiators (22);
A first cooling water circuit (10) in which cooling water circulates between the head side flow path (11) and the first radiator (12);
A second cooling water circuit (20) in which cooling water circulates between the block side flow path (21) and the second radiator (22);
A first circulation means (15) provided in the first cooling water circuit (10), for circulating cooling water between the head side flow path (11) and the first radiator (12);
A second circulation means (25) provided in the second cooling water circuit (20) for circulating cooling water between the block-side flow path (21) and the second radiator (22);
A heating heat exchanger (31) for heating the air blown toward the vehicle interior by heat exchange with the cooling water;
A cooling water path flowing from the first cooling water circuit (10) into the heating heat exchanger (31), and a cooling flowing from the second cooling water circuit (20) into the heating heat exchanger (31). A first path switching means (32) having a function of switching to either or both of the water path;
Cooling water path for returning cooling water from the heating heat exchanger (31) to the first cooling water circuit (10), and cooling from the heating heat exchanger (31) to the second cooling water circuit (20) A second path switching means (33) having a function of switching to one or both of the cooling water path from which water returns;
Control means (40) for controlling the first and second route switching means (32, 33),
The control means (40)
A cooling water path flowing into and out of the heating heat exchanger (31) flows into the heating heat exchanger (31) from the first cooling water circuit (10) and enters the first cooling water circuit (10). A first control for controlling the first and second path switching means (32, 33) so that the cooling water path returns to the cooling water path;
A cooling water path flowing into and out of the heating heat exchanger (31) flows into the heating heat exchanger (31) from the second cooling water circuit (20) and enters the second cooling water circuit (20). Second control for controlling the first and second path switching means (32, 33) so that the cooling water path returns to
After cooling water merges from both the first and second cooling water circuits (10, 20) and flows into the heating heat exchanger (31), cooling water flows out of the heating heat exchanger (31). A third control for controlling the first and second path switching means (32, 33) so that the first and second cooling water circuits (10, 20) flow into the first and second cooling water circuits (10, 20). An internal combustion engine cooling system.

The control means (40) includes at least a first water temperature sensor (41) for detecting a temperature of cooling water flowing out from the head side flow path (11) or from the head side flow path (11), and the block side Cooling detected by the second water temperature sensor (42) based on the detection result of the second water temperature sensor (42) for detecting the temperature of the cooling water flowing out from the flow path (21) or from the block side flow path (21). When the water temperature is lower than a predetermined temperature and lower than the cooling water temperature detected by the first water temperature sensor (41), the first control is executed, and the second water temperature sensor (42) is used. When the detected cooling water temperature is lower than the predetermined temperature and higher than the cooling water temperature detected by the first water temperature sensor (41), the second control is executed, and the first, first, After executing the control 2 above, If the load of the combustion engine (2) is determined to be lower than a predetermined value, the cooling system of an internal combustion engine according to claim 1, characterized in that to perform said third control.

The control means (40) includes at least a first water temperature sensor (41) for detecting a temperature of cooling water flowing out from the head side flow path (11) or from the head side flow path (11), and the block side When the internal combustion engine (2) is warmed up based on the detection result of the second water temperature sensor (42) that detects the temperature of the cooling water flowing out from the flow path (21) or from the block side flow path (21), When the cooling water temperature detected by the second water temperature sensor (42) is lower than the cooling water temperature detected by the first water temperature sensor (41), the first control is executed, and the second water temperature sensor (42 ), When the coolant temperature detected by the first coolant temperature sensor (41) is higher than the coolant temperature detected by the first coolant temperature sensor (41), the second control is executed, and after the internal combustion engine (2) is warmed up, Where the load of the internal combustion engine (2) is predetermined When it is determined that the load is higher than the value, the second control is executed, and when it is determined that the load of the internal combustion engine (2) is lower than the predetermined value, the third control is performed. The cooling system for an internal combustion engine according to claim 1 , wherein the cooling system is executed .

Before SL control means (40) is at least based on the detection result the first and the second water temperature sensor and a water temperature sensor (41) (42), said first control, and the second control, the and executes a third control, in claim 2 or 3, characterized in that for controlling the cooling water circulation amount of the cooling water circulation amount and the second circulation means (25) by said first circulation means (15) A cooling system for an internal combustion engine as described.