JP4529754B2 - Engine cooling system - Google Patents

Description

  The present invention relates to an engine cooling apparatus that cools an engine by circulating circulating water between a water jacket in the engine and a radiator, a heater unit for heating a vehicle interior, and the like.

  One of the methods for cooling the engine is a water cooling system in which cooling water is circulated and circulated between a water jacket and a radiator in the cylinder block and the cylinder head. In such a water cooling system, a heater unit is often disposed in parallel with the radiator of the cooling water circulation circuit in order to heat the vehicle interior using the heated cooling water as a heat source.

  For example, Patent Document 1 discloses that a radiator path that circulates and circulates cooling water between a water jacket and a radiator in the engine, a part of the radiator path and the path overlap, and the cooling water is supplied to the water jacket. Depending on the temperature of the cooling water discharged from the water jacket while being disposed in the heater path for circulating circulation, the water pump forcibly circulating the cooling water disposed in the overlapping part of each path, and the radiator path. An engine cooling device has been proposed that includes a thermostat that opens and closes a cooling water inflow passage for the radiator. In this apparatus, the inflow path to the radiator is closed until the cooling water is warmed to a predetermined temperature, and the cooling water is circulated through the heater path, thereby prematurely warming up the engine and improving the emission performance.

In addition, since the cooling device of this Patent Document 1 is configured so that the cooling water always flows through the heater path, the passenger compartment can be heated immediately after the engine is started, and the passenger's heating request is made immediately after the engine is started. There is an advantage that it can be satisfied.
JP 2004-353632 A

  By the way, in the heater unit, heat is exchanged between the air blown into the passenger compartment and the cooling water, so if the cooling water is circulated through the heater unit, the amount of heat of the cooling water is deprived, and it is attempted to warm up early. There was a limit.

  Here, when the engine is restarted shortly after the engine is stopped, neither the engine cooling water temperature nor the vehicle interior temperature has fallen to about the outside air temperature. May be able to raise. Even in such a case, if the cooling water is uniformly sent to the heater path, the vehicle interior can be heated immediately after the engine is started, but the heat quantity of the cooling water is deprived by the heater unit and the engine is warmed up. It will be delayed, and it will not be possible to send warm air of the appropriate temperature into the passenger compartment at an early stage. In such a case, the cooling water circulation circuit should be devised to warm the engine temperature at an early stage to further warm up the engine and to send warm air at a stable temperature into the passenger compartment at an early stage. It is considered to meet the requirements.

  In addition, when the outside air temperature is warm, such as in summer, the heater unit is rarely operated. Even in such a case, the cooling water is uniformly passed through the heater path, as described above, for a long warm-up time. This is not preferable from the viewpoint of improving emission.

  On the other hand, giving priority to early engine warm-up, for example, by providing a bypass that bypasses the radiator and heater unit in the cooling water circulation path, and circulating cooling fluid to the bypass by an electromagnetic valve, or by stopping the water pump, It is conceivable to cause the engine to warm up early by retaining the cooling water. However, when the temperature in the passenger compartment is extremely low, such as in winter, the passenger compartment can be heated even with warm air before reaching the appropriate temperature. It is considered that the heating requirement is satisfied.

  In addition, for example, adopting a configuration such as switching a solenoid valve based on a signal from a sensor leads to an increase in cost, and the water pump is often driven using an engine, and the water pump can be stopped. There is also a problem that the pump has to be driven separately from the engine, resulting in high manufacturing costs.

  In view of the above circumstances, the present invention satisfies the occupant's heating requirements immediately after starting the engine as much as possible while suppressing the manufacturing cost as much as possible, and realizes early engine warm-up as much as possible to improve emissions. The goal is to improve.

  An engine cooling apparatus according to the present invention includes a radiator path that circulates a cooling fluid between a water jacket and a radiator in the engine at a predetermined path opening temperature or higher, and the radiator path partially overlaps with the water jacket. A heater path that circulates the cooling fluid between the vehicle and the heater unit for heating the vehicle interior, a water pump that is disposed in an overlapping portion of each path and forcibly circulates the cooling water, and an upstream of the water pump A shortcut path that short-circuits the path on the downstream side and the downstream side, and an on-off valve mechanism that adjusts the flow rate of the cooling fluid flowing into the water jacket by opening and closing the shortcut path. A valve body that opens and closes, an elastic member that biases the valve body in the closing direction, and a shape memory alloy. A first shape memory alloy spring that biases the valve body in the opening direction at a predetermined shape recovery temperature or higher, and a second shape that is made of a shape memory alloy and biases the valve body in the closing direction at a predetermined shape recovery temperature or higher. A memory alloy spring, wherein the first shape memory alloy spring has a shape recovery temperature set to a predetermined first switching temperature lower than the path opening temperature, while the second shape memory alloy spring The shape recovery temperature is set to a predetermined second switching temperature that is lower than the path opening temperature and higher than the first switching temperature, and is disposed at a position that can immediately respond to changes in the temperature of the cooling water flowing through each path. In the on-off valve mechanism, the cooling water temperature is lower than the first switching temperature by the combined urging force of the urging force by the elastic member and the temperature condition urging force by the first and second shape memory alloy springs. When the valve body is closed When the cooling water temperature is equal to or higher than the first switching temperature and lower than the second switching temperature, the valve body is biased to the open state, and when the cooling water temperature is equal to or higher than the second switching temperature, The valve body is configured to be biased to a closed state.

  According to the present invention, there is provided a shortcut path that short-circuits the upstream and downstream paths of the water pump, and an on-off valve mechanism that adjusts the flow rate of the cooling fluid flowing into the water jacket by opening and closing the shortcut path. The on-off valve mechanism uses the characteristics of the first and second shape memory alloy springs having different shape recovery temperatures to apply the biasing force by the elastic member and the temperature condition by the first and second shape memory alloy springs. Since the opening and closing of the valve body is controlled based on the cooling water temperature by the combined urging force with the urging force, the first and second switching temperatures are set in association with the assumed in-vehicle temperature. The degree of heating demand of the occupant can be easily determined based on the engine temperature at the time of starting with a typical configuration. By giving priority to at least one of the passenger's heating request and early warm-up request, the cooling fluid path is switched in three stages so as to satisfy the other request as much as possible, thereby suppressing an increase in cost. However, both of these requirements can be effectively made compatible.

  That is, when the cooling water temperature is equal to or lower than the first switching temperature, the first and second shape memory alloy springs have not reached the shape recovery temperature, and the valve body is biased to the closed state by the biasing force of the elastic member. The Further, the radiator path is closed because the path opening temperature has not been reached. Therefore, in this state, the cooling fluid is circulated between the water jacket and the heater unit. Then, by setting the first switching temperature to the cooling water temperature at which the vehicle interior temperature is assumed to be sufficiently lowered, the cooling fluid such as cooling water is sent to the heater unit instead of the radiator to warm up as early as possible. In this way, it is possible to satisfy the occupant's heating request as much as possible by giving priority to heating by configuring the engine so that warm air can be sent into the passenger compartment even immediately after the engine is started.

  On the other hand, when the temperature of the cooling fluid at the time of starting the engine is equal to or higher than the first switching temperature and lower than the second switching temperature, the first shape memory alloy spring reaches the shape recovery temperature and generates a biasing force. The valve body is biased to the open state by the combined biasing force of the member and the first shape memory alloy spring. In this state, the cooling fluid can be warmed up in a short period of time. Therefore, by switching the valve body to the open state and opening the shortcut path, the water jacket inflow flow rate is eliminated or reduced from the normal flow rate above. Emission characteristics are improved by warming the cooling fluid early, thereby realizing early warm-up and reducing CO, HC, etc. due to incomplete combustion. Also, in this state, it is assumed that the interior temperature has not decreased so much, so the cooling water is quickly warmed up by early warm-up, and then the warm air at a stable temperature is sent into the passenger compartment, so that passengers can request heating. Can be satisfied as much as possible.

  Further, when the temperature of the cooling fluid at the start of the engine is equal to or higher than the second switching temperature, the first and second shape memory alloy springs both reach the shape recovery temperature and generate a biasing force. The valve body is biased to the closed state by the combined biasing force of the second shape memory alloy spring. In this state, since there is no need for warm-up, the normal operation state is ensured by closing the shortcut path and setting the flow rate of the cooling fluid flowing into the water jacket as the normal flow rate.

  Moreover, since the switching of the valve bodies of these on-off valve mechanisms is performed exclusively by a mechanical configuration, it can be easily configured, and an increase in cost can be suppressed as much as possible in this improvement.

  Here, the first shape memory alloy spring may be disposed at a position that can immediately respond to a change in temperature of the cooling water flowing through each of the paths, but the valve body is a cooling that flows outside. It has a blunt greenhouse in which the temperature of the cooling fluid existing inside with respect to the temperature change of the fluid follows with a predetermined delay, and the first shape memory alloy spring is arranged in the blunt greenhouse. Preferred (claim 2).

  According to this configuration, when the engine is started in a state where the cooling fluid temperature is lower than the first switching temperature, even if the temperature of the cooling fluid flowing in each path becomes equal to or higher than the first switching temperature, Since the cooling fluid in the variable temperature chamber does not immediately exceed the first switching temperature but changes with a predetermined delay, even if the cooling fluid shifts to the first switching temperature after engine startup, the inflow flow rate to the water jacket with a predetermined delay. Is reduced. Alternatively, when the temperature of the cooling fluid flowing during the delay becomes equal to or higher than the second switching temperature, the combined biasing force of the elastic member and the second shape memory alloy spring is the biasing force of the first shape memory alloy spring. Therefore, the control for switching the valve body to the open state is omitted, and the control is performed so that the cooling fluid temperature is equal to or higher than the second switching temperature. That is, the valve body is maintained in the closed state.

  Therefore, when the engine is started from a temperature where the cooling fluid is lower than the first switching temperature, for example, from an extremely cold state, the period during which the valve body is opened is shortened or the period is omitted. After starting the vehicle, the period during which the warm air cannot be sent by the heater unit is shortened until the temperature inside the vehicle rises, or the state in which the warm air can be sent is maintained, and the passenger's heating request is more fully met. Can be satisfied.

  Here, the heater path may be always open, but the on-off valve mechanism is housed in a housing disposed adjacent to the water pump, and the internal space of the housing is fed out from the heater unit. One end of the heater inflow port for introducing the cooled water is opened, and the valve body closes the opening of the heater inflow port in the opened state and opens the port opening in the closed state. It is preferable to be housed in a housing (claim 3).

  If comprised in this way, a heater inflow port can be opened and closed using the valve body which opens and closes a shortcut path | route, and it is a heater in the period from the 1st switching temperature which gives priority to the early warming up of an engine to the 2nd switching temperature. The inflow port is closed to allow the cooling fluid to stay in the water jacket, thereby further shortening the warm-up period.

  In this case, the specific configuration of the water pump is not particularly limited, and a housing in which the on-off valve mechanism is housed may be provided separately, but the water pump is configured as a centrifugal water pump. The housing is disposed upstream of the water jacket and downstream of the housing, and the internal space of the housing communicates with the upstream end of the water jacket through a shortcut path that forms a shortcut path and from the radiator. One end of a radiator inflow port for introducing the fed cooling water is opened, and a thermostat for opening and closing the radiator path based on the cooling water temperature is preferably disposed in the housing. .

  That is, with this configuration, a centrifugal pump that is widely used as this type of water pump can be used to manufacture a general-purpose product at a low cost, and an existing thermostat housing can be used. The housing for housing the on-off valve mechanism can be formed, and the cooling device according to the present invention can be applied to a conventionally widely used device without significant design change. Therefore, this cooling device can be manufactured at a lower cost. In addition, when a centrifugal pump that uses the driving force of the engine is used, the flow rate of the cooling water in the water jacket can be reduced or retained with a simple configuration of opening and closing the shortcut path, which is more inexpensive and reliable. The route can be switched.

  In the present invention, the path for circulating the cooling fluid (cooling fluid circulation path) is not limited to the radiator path and the heater path, and connects the cooling fluid inlet / outlet of the water jacket bypassing the radiator and the heater unit. A sub-circulation path may be further provided, and when the sub-circulation path is provided, an oil heat exchanger for exchanging heat between the cooling fluid and the engine oil is disposed in the sub-circulation path. Preferred (claim 5).

  If comprised in this way, not only heating property and the early warming-up of an engine but warming-up promotion of engine oil can be aimed at, and it becomes more practical.

  In this case, it is preferable that the sub-circulation path is provided with a heat exchanger bypass that bypasses the oil heat exchanger, and a pressure relief valve is disposed in the heat exchanger bypass. .

  That is, for example, when the flow rate of the cooling fluid flowing through the sub-circulation path increases as the engine speed increases, the pressure of the fluid inlet of the oil heat exchanger increases. If the pressure exceeds a certain value, the pressure relief valve operates and the cooling fluid flows through the heat exchanger bypass, so that hose disconnection or the like accompanying the pressure increase can be effectively prevented.

  According to the engine cooling device of the present invention, it is possible to easily determine the degree of the passenger's heating request through the engine temperature at the time of starting by the mechanical configuration, and based on the degree of the passenger's heating request, While giving priority to at least one of the heating request and the early warm-up request, the cooling fluid path is switched in three stages so as to satisfy the other request as much as possible, while suppressing an increase in cost. Both requirements can be effectively made compatible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a water-cooled engine according to the present invention, and FIG. 2 is an explanatory diagram schematically showing a cooling device for the engine.

  The engine 1 is mounted horizontally in the engine room at the front of the vehicle and below the hood, that is, so that the crankshaft direction is along the vehicle width direction. The engine 1 is an in-line four-cylinder engine in which four cylinders are arranged in series along the crankshaft direction, and an intake port 11 and an exhaust port 12 that open to the combustion chambers above the cylinders 10A to 10D are respectively in a cylinder row. A so-called crossflow type engine in which the intake port 11 and the exhaust port 12 are arranged in parallel to each other and extend on opposite sides of a combustion chamber provided in the upper part of each cylinder 10A to 10D. is there. As a result, as shown in FIG. 2, each intake port 11 is disposed on the front side in the vehicle front-rear direction with respect to the engine 1, while each exhaust port 12 is disposed on the rear side in the vehicle front-rear direction with respect to the engine 1. ing.

  The engine 1 is a water-cooled engine that uses a liquid such as cooling water as a medium for releasing heat generated by combustion in the cylinders 10A to 10D into the atmosphere, and is incorporated in a cooling device including a radiator 5 and the like. It is comprised so that it may be cooled by.

  That is, the cooling device for the engine 1 includes an engine body 2 in which a water jacket 20 is provided, a radiator 5 disposed in front of the engine body 2, and a heater unit disposed in the rear of the engine body 2. 6, inlet pipes 13 and 14 for sending cooling water from the water jacket 20 to the radiator 5 or the heater unit 6, and outlet pipes 15 for returning cooling water from the radiator 5 or the heater unit 6 to the water jacket 20, 16, a bypass pipe 17 that bypasses the radiator 5 and the heater unit 6, and a pressure release pipe 23 that interposes the inlet pipes 13, 14 and the pressure in the bypass pipe 17 (see FIG. 2). And the outlet pipes 15 and 16, The thermostat 7 is disposed in a thermostat housing 71 to which the downstream ends of the spipe 17 and the pressure adjusting pipe 18 are connected, and opens and closes the cooling water inflow passage from the radiator 5 according to the cooling water temperature, and the thermostat 7 and the water A water pump 8 interposed between the jacket 20 and forcibly circulating cooling water is provided.

  In this embodiment, as shown in FIG. 2, an oil cooler 50 (corresponding to an example of a heat exchanger) that cools engine oil by heat exchange in the bypass path constituted by the bypass pipe 17 or the engine 1. An ATF warmer 52 (corresponding to an example of a heat exchanger) for warming oil for the automatic transmission 51 disposed on the side of the automatic transmission 51 is disposed.

  As a result, the cooling device includes a radiator path for circulating and circulating cooling water between the water jacket 20 and the radiator 5, a heater path for circulating and circulating cooling water between the water jacket 20 and the heater unit 6, and a bypass. A bypass path (corresponding to an example of a sub-circulation path) that includes a pipe 17 and connects a cooling water inlet (upstream opening of a cooling water inflow port 231 described later) of the water jacket 20 and a cooling water discharge port 205; And a cooling water circulation path including a pressure adjusting bypass path that bypasses the radiator 5, the heater unit 6, the oil cooler 50, and the ATF warmer 52 and adjusts the pressure of the upstream cooling water circulation path. Become. In addition, these paths (a heater path, a bypass path, etc. in this embodiment) may partially overlap.

  Specifically, as shown in FIG. 1, the engine 1 includes an engine main body 2 constituting each cylinder, an oil pan 3 assembled to the engine main body 2 from the lower side, and an engine main body 2 from the upper side. An assembled cylinder head cover 4 is provided. The engine main body 2 is a cast product made of cast iron or aluminum alloy, and is attached to a cylinder block 21 constituting a main body portion of the cylinder via a gasket (not shown) on the upper side of the cylinder block 21. A cylinder head 22 is provided. Inside the cylinder block 21 and the cylinder head 22 are formed block side and head side water jackets 20a and 20b that form cooling passages, respectively, and the cooling water can be circulated and circulated in the engine body 2. That is, these water jackets 20a and 20b are gaps formed around the cylinders 10A to 10D in the cylinder block 21 or the cylinder head 22, and constitute a passage (cooling passage) for circulating cooling water. . There are various cooling water circulation methods in the water jackets 20a and 20b. In this embodiment, the block-side water jacket 20a has a U-turn method in which the cooling water circulates in one direction around the cylinders 10A to 10D. On the other hand, the head-side water jacket 20b employs an axial flow system in which cooling water is circulated in parallel along the cylinder row direction from one end side of the cylinder head 22 to the other end side.

  As shown in FIG. 2, the block-side water jacket 20 a is provided so as to surround the cylinders 10 </ b> A to 10 </ b> D along the peripheral edge of the cylinder block 21, and one end of the block-side water jacket 20 a is connected to the water pump via the cooling water inflow port 231. 8, and the other end communicates with the water jacket 20 b of the cylinder head 22.

  On the other hand, the head-side water jacket 20b extends from one end side of the cylinder head 22 to the other end side as shown in FIG. 2 between a bottom deck (not shown) and a middle deck (not shown). Is communicated with the head-side water jacket 20b through first to fourth communication paths 201 to 204 described later, and the other end communicates with the water outlet member 24 through the cooling water outlet port 205. The first to fourth communication passages 201 to 204 are solidly opened at one end portion of the head-side water jacket 20b, so that the coolant can flow in parallel in the cylinder row direction. In addition to the first to fourth communication paths 201 to 204, the head-side water jacket 20 b has an air vent path (not shown) whose path cross-sectional area is smaller than the cross-sectional area of these paths 201 to 204. ) Through the block-side water jacket 20a.

  The block-side water jacket 20a will be described in more detail. The block-side water jacket 20a has a first cooling passage 232a extending backward from one side in the longitudinal direction (right side in the example) of the cylinder block 21 from the cooling water inflow port 231. The other end side in the longitudinal direction of the cylinder block 21 along the cylinder row direction (in the example shown in the drawing), the rear side portion of the cylinder block 21 communicates with the first cooling passage 232a, in other words, the exhaust side portion of the cylinder block 21. A second cooling passage 232b extending to the left), a third cooling passage 232c communicating with the second cooling passage 232b and extending forward at the other end (the left side in the figure) of the cylinder block 21, and the third cooling passage 232c communicates with the front side of the cylinder block 21, in other words, the intake side of the cylinder block 21. A fourth cooling passage 232d back (right side in the illustrated example) at one end of the cylinder block 21 along the column direction, the cooling water is circulated in the order of first to fourth cooling passage 232A～d.

  In the first cooling passage 232a of the block-side water jacket 20a, first and second communication passages 201 and 202 communicating with the head-side water jacket 20b are opened, and the upstream end portion of the second cooling passage 232b and the fourth A third communication path 203 or a fourth communication path 204 that communicates with the head-side water jacket 20b is opened at the downstream end of the cooling path 232d.

  The inflow amount of the cooling water flowing from the block-side water jacket 20a to the head-side water jacket 20b through the communication paths 201 to 204 is the second, first, fourth, and third communication paths 202, 201, 204, 203. In this embodiment, the passage cross-sectional area of the communication passage is adjusted so as to increase in order of the inflow amount.

  On the other hand, the cooling water inflow port 231 is configured to reduce the inflow resistance to the first cooling passage 232a by extending in the substantially same direction as the extending direction of the first cooling passage 232a. A short-circuit passage 232e having one end communicating with the first cooling passage 232a is provided at the peripheral edge portion of the cylinder block 21 between the base end portion of the first cooling passage 232a and the distal end portion of the fourth cooling passage 232d. The short-circuit passage 232e and the fourth cooling passage 232d are partitioned by a partition wall 233 so that the cooling water does not flow directly therebetween.

  As shown in FIG. 3, the short-circuit passage 232 e includes a jacket portion 2321 that extends from the first cooling passage 232 a to the fourth cooling passage 232 d along the periphery of the cylinder 10 </ b> A disposed on one side in the longitudinal direction of the cylinder block 21. , And a short-circuit port portion 2322 extending from the front end portion of the jacket portion 2321 into a thermostat housing 71 described later substantially parallel to the cooling water inflow port 231. As shown by a two-dot chain line in FIG. 3, one end of a heater inflow port 7a, which will be described later, is opened in this short-circuit port portion 2322, and a valve body 91 of an on-off valve mechanism 9 that opens and closes this short-circuit passage 232e is arranged. It is installed.

  The on-off valve mechanism 9 is disposed in the thermostat housing 71 on the downstream side of the short-circuit passage 232e, and is mechanically opened and closed based on the temperature of the cooling water flowing through the housing 71. It is configured. When the short circuit passage 232e is opened, most of the cooling water flowing in from the cooling water inflow port 231 is introduced into the short circuit passage 232e that is decompressed by the suction force of the water pump 8, and through this short circuit passage 232e. It is introduced into a thermostat housing 71 located on the upstream side of the water pump 8. Therefore, when the short-circuit passage 232e is open, most of the cooling water sent out by the water pump 8 circulates through the short-circuit passage 232e and is circulated to the block-side and head-side water jackets 20a and 20b. Reduce to almost no water flow. That is, the short-circuit passage 232e and the on-off valve mechanism 9 constitute a flow rate adjusting mechanism that adjusts the flow rate of the cooling water flowing into the water jacket 20.

  When the engine is in an extremely cold state, that is, the on-off valve mechanism 9 is lower than the radiator path opening temperature (about 76 to 82 ° C. in this embodiment) when the cooling water temperature in the slow-changing greenhouse 91f described later is lower than the predetermined value. When the temperature is less than the extremely cold reference temperature (about 20 ° C. in the present embodiment), the short-circuit path 232e is closed, and the engine is in a cold state, that is, the temperature of the cooling water flowing through the thermostat housing 71 Is less than a predetermined low cold reference temperature (about 70 ° C. in the present embodiment) that is lower than the radiator path opening temperature and exceeds the above-mentioned extremely cold reference temperature, the short circuit 232e is opened, and the engine is in a warm state. When the cooling water temperature exceeds the low cold reference temperature, the short-circuit path 232e is closed.

  Specifically, as shown in FIG. 3, the on-off valve mechanism 9 includes a valve body 91 that opens and closes the short-circuit passage 232e, an urging member 92 that urges the valve body 91 to a closed state, and a cooling water temperature. A first sensation is provided to generate a predetermined urging force when the temperature is equal to or higher than the extremely cold reference temperature, and to urge the valve body 91 to an open state by the generated urging force and the urging force of the urging member 92. The urging member 93 generates a predetermined urging force when the cooling water temperature is equal to or higher than the low cold reference temperature, and the generated urging force and the urging force by the urging member 92 and the first temperature sensing urging member 93 are generated. And a second temperature-sensing urging member 94 that urges the valve body 91 in a closed state by a combined urging force.

  As shown in FIG. 3, the valve body 91 is formed according to the cross-sectional shape of the short-circuit port portion 2322 of the short-circuit passage 232 e, and the valve body 91 a disposed at the tip is located at the short-circuit port portion 2322, so that The passage 232e is closed and located in the jacket portion 2321 so that the passage 232e is opened. The valve body 91a is supported by a valve rod 91b formed integrally with the valve body 91a. The valve rod 91b is integrally formed with a bottomed cylindrical accommodating portion 91c at the end opposite to the valve main body 91a.

  The accommodating portion 91c has a flange portion 91d having a peripheral wall whose diameter is increased stepwise at a substantially central portion in the longitudinal direction and is projected to the outside at an enlarged opening edge thereof. A temperature sensitive biasing member 93 is accommodated. The small-diameter portion of the accommodating portion 91c is formed so as to be fitted into the short-circuit port 2322 of the short-circuit passage 232e. In this embodiment, the heater inflow port that opens to the short-circuit port portion 2322 as the valve body 91 opens and closes. 7a is configured to be opened and closed by the peripheral surface of the small diameter portion. That is, when the valve body 91 is in the closed state, as shown in FIG. 3, the heater inflow port 7a is configured to be opened by the outer peripheral surface of the small diameter portion in the housing portion 91c, and the valve body 91 is in the open state. 4, the heater inflow port 7 a is configured to be closed by the outer peripheral surface of the small diameter portion of the accommodating portion 91 c as shown in FIG. 4. Although not shown in the drawing, the cooling water flowing in from the heater inflow port 7 a is introduced into the water pump 8 through the thermostat housing 71, so that the short-circuit port portion 2322, a thermostat housing 71 and a valve body described later are provided. 91 is formed.

  An inflow suppression lid 91e that suppresses the inflow of cooling water into the accommodation space of the first temperature-sensitive biasing member 93 is fitted into the large-diameter portion of the accommodation portion 91c. The inflow suppressing lid 91e is formed separately from the accommodating portion 91c and is attached to a predetermined portion of a thermostat housing 71 described later. This attachment position is set so as to come into contact with the stepped portion accompanying the diameter expansion of the accommodating portion 91c when the valve body 91 is in the closed state.

  Further, the size of the inflow suppressing lid 91e is set so that the outer peripheral edge thereof is in sliding contact with the inner peripheral surface of the large diameter portion of the housing portion. Therefore, although it is difficult for cooling water to flow into the housing space of the housing portion 91c closed by the inflow restraining lid 91e from the flow path outside the housing portion 91c, the outer peripheral edge of the inflow restraining lid 91e and the inside of the housing portion 91c Cooling water comes and goes to and from the flow path through a slight gap with the peripheral surface. As a result, the accommodation space in the accommodation portion 91c is configured as a slow change greenhouse 91f in which the temperature of the cooling water existing in the space follows the temperature change of the external cooling water with a predetermined delay.

  As described above, the first temperature sensitive urging member 93 is disposed in the slow change greenhouse 91f. The first temperature-sensitive biasing member 93 is a compression coil spring formed from a shape memory alloy (for example, Ni—Ti alloy, Cu—Zu—Al alloy, etc.), a so-called shape memory alloy compression coil spring, The valve body 91a is extended by being recovered, and thereby urges the valve body 91a in the opening direction.

  The first temperature-sensitive biasing member 93 has a one-way shape memory effect that stores the shape of the temperature rise, and the valve body 91a is opened and closed by a bias method using the biasing member 92 as a bias spring. It is supposed to be switched. The bias method means that a shape memory alloy showing a one-way shape memory effect is loaded with a predetermined external stress (for example, biasing force by a bias spring) so that the shape changes not only when the temperature rises but also when the temperature falls. A method of repeatedly performing a two-way operation.

  Further, the shape recovery temperature of the first temperature-sensitive biasing member 93, that is, the temperature at which the shape recovers due to the shape memory effect, is set to the extremely cold reference temperature (about 20 ° C. in the present embodiment). Therefore, when the temperature of the cooling water in the slow-changing greenhouse 91f becomes equal to or higher than the extremely cold reference temperature, the first temperature-sensitive biasing member 93 generates a biasing force that biases the valve body 91a in the opening direction. It has been. The urging force generated by the first temperature-sensitive urging member 93 by this shape memory effect is set to a value larger than the urging force of the urging member 92. Thereby, as will be described later, the first temperature-sensing biasing member 93 resists the biasing force of the biasing member 92 that biases the valve body 91 in the closed state, from the closed state shown in FIG. 4 can be switched to the open state.

  The urging member 92 is a compression coil spring formed of steel or the like, and functions as a bias spring for the first and second temperature-sensitive urging members 93 and 94. The urging member 92 is disposed outside the valve body 91 (specifically, the large-diameter portion of the accommodating portion 91c). One end of the urging member 92 abuts on the flange portion 91d of the accommodating portion 91c and the other end is the bottom surface of the thermostat housing 71. The valve body 91 is urged in the closing direction by abutting against 71a.

  A second temperature sensitive urging member 94 is disposed outside the urging member 92 in the radial direction. The second temperature-sensitive biasing member 94 is a compression coil spring formed from a shape memory alloy (for example, Ni—Ti alloy, Cu—Zu—Al alloy, etc.), a so-called shape memory alloy compression coil spring, The valve body 91a is expanded by being recovered, and thereby urges the valve body 91a in the closing direction. That is, one end of the second temperature-sensing biasing member 94 abuts on the flange portion 91d of the accommodating portion 91c and the other end abuts on the bottom surface 71a of the thermostat housing 71, whereby the valve body 91 is closed in the closing direction. It is supposed to be energized.

  The second temperature-sensitive urging member 94 has a one-way shape memory effect in which the shape when the temperature rises is stored, and the urging member 92 and the first temperature-sensitive urging member 93 are used as bias springs to control the valve. The main body 91a is switched between an open state and a closed state. In addition, the shape recovery temperature of the second temperature sensitive biasing member 94 is set to a low cold reference temperature (about 70 ° C. in this embodiment) higher than the shape recovery temperature of the first temperature sensitive biasing member 93. ing. Therefore, when the temperature of the cooling water flowing outside the housing portion 91c and inside the thermostat housing 71 becomes equal to or higher than the low cold reference temperature, the second temperature sensitive biasing member 94 is biased by the biasing member 92. Further, a biasing force is generated on the valve body 91a biased in the open state by the biasing force of the first temperature sensing biasing member 93, and the valve body 91a is switched to the closed state. That is, the urging force generated by the second temperature-sensitive urging member 94 due to the shape memory effect is larger than the combined urging force that is a combined force of the urging forces of the urging member 92 and the first temperature-sensitive urging member 93. Is set to a value. In other words, the sum of the urging forces of the urging member 92 and the second temperature sensitive urging member 94 is set to a value larger than the urging force of the first temperature sensitive urging member. Thereby, the valve body 91 urged by the combined urging force of the urging member 92 and the first temperature-sensing urging member 93 is changed from the open state shown in FIG. The closed state shown in FIG.

  On the other hand, referring back to FIGS. 1 and 2, the water pump 8 is disposed upstream of the block-side water jacket 20a. Specifically, the water pump 8 is attached to one side end portion in the upper front portion of the cylinder block 21 (in the illustrated example, the upper right end portion of the front surface with reference to the front-rear direction of the vehicle). The water pump 8 is a spiral centrifugal pump, and is connected to a crank pulley 55 disposed at the lower end of one side surface of the cylinder block 21 via a V belt (not shown). An impeller 82 (see FIG. 3) disposed in the water pump housing 81 (see FIG. 3) is driven to rotate by using a rotational driving force. Therefore, the rotational speed of the water pump 8 is determined according to the engine rotational speed. Therefore, in a state where the short circuit 232e is closed, that is, in a normal state, the normal flow rate of the cooling water introduced into both the block side and the head side water jackets 20a and 20b by the water pump 8 is the engine rotation speed. The flow rate depends on the speed.

  An upstream side of the water pump 8 is provided with a thermostat 7 that maintains the cooling water temperature at an appropriate temperature by opening and closing the radiator path according to the cooling water temperature. The thermostat 7 is adjacent to the water pump 8. It is housed in a thermostat housing 71 attached to the front surface of the cylinder block 21.

  Although not shown, the thermostat 7 opens and closes the radiator path based on the cooling water temperature, and adjusts the cooling water temperature to an appropriate range in the engine operating state. In this embodiment, the thermostat 7 pushes out the needle by utilizing the so-called wax type, that is, the wax sealed in the container melts and expands as the temperature rises, and is urged in the closing direction by this pushing force. The valve body is configured to open. In the thermostat 7 of this embodiment, the temperature for opening the valve element (path opening temperature) is set to about 76 to 82 ° C. by selecting the wax to be enclosed. That is, the thermostat 7 is configured not to be electrically operated but to be mechanically operated.

  As shown in FIGS. 3 and 4, the thermostat housing 71 includes a front opening type block side case 72 formed integrally with the cylinder block 21 and a lid-like case 73 that closes the opening. The on-off valve mechanism 9 is disposed in the block side case 72, while the thermostat 7 is disposed in the lid-like case 73. The block-side case 72 communicates with the block-side water jacket 20a through the short-circuit passage 232e on the bottom surface 71a, and communicates with the interior of the water pump housing 81 on the peripheral side surface.

  Further, the thermostat housing 71 is provided with a heater inflow port 7a opened on the upper surface thereof, and a pressure adjusting inflow port 7b and a radiator inflow port 7c opened on the front surface thereof. The heater inflow port 7a is connected to a common pipe 19 constituted by connecting the heater outlet pipe 16 and the bypass pipe 17 at the downstream end. A pressure adjusting pipe 18 is connected to the pressure adjusting inflow port 7b, while a radiator outlet pipe 115 is connected to the radiator inflow port 7c for returning the cooling water heat-exchanged in the radiator 5 to the engine body 2. .

  A water outlet member 24 is provided on the upper side of the engine body 2 on the side opposite to one side in the vehicle width direction (right side in the illustrated example) where the water pump 8 is provided. One end of the water outlet member 24 communicates with the head-side water jacket 20b, and the other end branches to each of four ports: a radiator outlet port, a heater outlet port, a pressure adjusting outlet port, and a pressure adjusting outlet port. Is provided. Each port is connected to a radiator inlet pipe 13 and a heater inlet pipe 14 for allowing cooling water heated in the engine main body 2 to flow into the radiator 5 and the heater unit 6, as well as a bypass pipe 17 and a pressure adjusting pipe 18. Is connected.

  The pressure release valve 23 provided in the pressure adjusting pipe 18 is an internal detection type direct acting pressure reducing valve in this embodiment, but its configuration is well known, and in this embodiment The description is omitted.

  Next, the operation of the cooling device for the engine 1 configured as described above will be described. FIG. 5 shows a time change (FIG. (A)) of the coolant temperature that rises as the engine starts, and a time change (FIGS. (B) to (b) of the open / close state of each path based on the engine state at the time of engine start. It is explanatory drawing which shows d)).

  In this device, the engine temperature (cooling water temperature) at the time of starting the engine is determined based on the shape memory effect of the first and second temperature sensitive urging members 93 and 94, and the circulation path of the cooling water based on the engine temperature. Can be switched.

  First, the case where the engine 1 is started from the S1 state in FIG. 5A when the engine 1 is in an extremely cold state will be described. When the engine 1 is in an extremely cold state, the first and second temperature-sensitive biasing members 93 and 94 have not reached the shape recovery temperature, and therefore only the biasing member 92 generates a biasing force. In this state, the short-circuit passage 232e is closed by the valve body 91 of the on-off valve mechanism 9. Further, at this time, the heater inflow port 7a is not closed by the accommodating portion 91c of the valve body 91 and is opened, so that the heater path and the bypass path are open. On the other hand, since the cooling water temperature has not reached the path opening temperature, the thermostat 7 is in a state of closing the radiator path.

  When the engine 1 is operated, the crank pulley 55 is rotated to operate the water pump 8, and all of the cooling water discharged from the water pump 8 is introduced into the first cooling passage 232 a of the water jacket 20. It will be. A part of this cooling water is introduced into the head side water jacket 20b through the first to third communication paths 201 to 203, and the rest of the cooling water flows through the block side water jacket 20a and exhausts the cylinder block 21 thereof. The U-turn is cooled from the side of the side and introduced into the head side water jacket 20b through the fourth communication path 204. In the head-side water jacket 20b, the cooling water introduced through the second and third communication passages 202 and 203 circulates exclusively along the cylinder row direction along the exhaust side of the cylinder head 22, and the first, fourth, The cooling water introduced through the communication passages 201 and 204 flows exclusively along the cylinder row direction on the side of the cylinder block 21 on the intake side. The cooling water flowing through the head side water jacket 20 b joins and is discharged to the water outlet member 24 through the cooling water outlet 205.

  This cooling water is diverted by the water outlet member 24 and is introduced into the flowing water path opened in the extremely cold state, that is, the flowing water path constituted by the heater inlet pipe 14 and the bypass pipe 17. As described above, when the engine 1 is in an extremely cold state, cooling water having a normal flow rate, that is, cooling water having a flow rate corresponding to the engine rotation speed flows through the heater path and the bypass path. Therefore, although it is the cooling water in the temperature rising process, the cooling water can be introduced into the heater unit 6 and the vehicle interior can be effectively heated by using the cooling water temperature. That is, in the extremely cold state of the engine 1, the vehicle interior temperature is considered to be extremely low, so that the vehicle interior can be effectively heated even with warm air generated by heat exchange with the cooling water in such a temperature rising process. Can do. Therefore, as compared with a state in which the heater unit 6 cannot be operated until the cooling water temperature is raised to an appropriate temperature, the passenger compartment can be heated to some extent earlier, and the passenger's heating request can be satisfied.

  Here, when the engine speed rapidly increases, the discharge amount from the water pump 8 increases accordingly, and the internal pressure of the bypass pipe 17 and the heater inlet pipe 14 upstream of the ATF warmer 52 increases. When the internal pressure of these pipes 17 and 14 rises, there is a concern that these pipes may fall off. However, according to this cooling device, the internal pressure of the pressure adjusting pipe 18 also rises along with these pressure rises, and the pressure release is accompanied accordingly. Since the valve 23 is opened, it is possible to effectively prevent the pipes 14 and 17 from falling off.

  Cooling water discharged from the heater unit 6, the oil cooler 50, and the ATF warmer 52 is introduced into the thermostat housing 71 through the heater inflow port 7a. Then, the cooling water flows through the thermostat housing 71 and is reintroduced into the water pump 8.

  When the cooling water circulates in the heater path and the bypass path in this way, the cooling water temperature efficiently rises and exceeds the extremely cold reference temperature Tb. Here, even when the temperature of the cooling water flowing through the thermostat housing 71 exceeds the extremely cold reference temperature Tb, the first temperature-sensitive biasing member 93 does not generate a biasing force. That is, the first temperature-sensing urging member 93 generates an urging force with a predetermined delay because the internal cooling water is stored in the slow-changing greenhouse 91f where the temperature changes with a predetermined delay. In this embodiment, in the present embodiment, the delay is longer than the time until the temperature of the cooling water flowing in the path reaches from the extremely cold reference temperature Tb to the low cold reference temperature Ts. Since the first temperature-sensing urging member 93 does not generate urging force even when the engine 1 is in a small cold state, the on-off valve mechanism 9 closes the short-circuit passage 232e. Keeps the state.

  When the temperature of the cooling water flowing through the thermostat housing 71 exceeds the low cold reference temperature Ts, the second temperature-sensitive biasing member 94 generates a biasing force. Since the second temperature-sensing urging member 94 urges the valve body 91 of the on-off valve mechanism 9 to the closed state, the valve body 91 keeps the state where the short-circuit passage 232e is closed. At this time, even if the first temperature-sensitive biasing member 93 generates a biasing force when the temperature of the cooling water in the slow change greenhouse 91f exceeds the extremely cold reference temperature Tb, the biasing by the first temperature-sensing biasing member 93 is performed. Since the urging force is smaller than the combined urging force of the urging member 92 and the second temperature-sensitive urging member 94 (the sum of the urging forces of the urging members 92 and 94), the valve body 91 is in a state where the short circuit passage 232e is closed. Keep.

  Subsequently, when the cooling water temperature further rises and exceeds the path opening temperature To, the thermostat 7 is switched to the open state, whereby the radiator path is opened and the cooling water is efficiently cooled by the radiator 5. As a result, when the cooling water temperature becomes equal to or lower than the path opening temperature To, the thermostat 7 switches to the closed state and the cooling water temperature starts to rise again. The cooling water is controlled to an appropriate temperature range while repeating this operation.

  As described above, when the engine 1 is in an extremely cold state at the time of start-up, as shown in FIG. 5B, the shortcut path including the short-circuit path 232e is closed so that the water jacket 20 is normally closed. The flow rate of cooling water circulates and the heater path is always open. The heater unit 6 can be operated at any time immediately after the engine 1 is started. The passenger compartment can be heated as much as possible by effectively sending the wind to satisfy the passenger's heating request as much as possible. Moreover, in this apparatus, when the engine 1 is operated in an extremely cold state, the cooling water flows through the heater path and the bypass path instead of the radiator 5, so that a certain degree of early warm-up can be achieved.

  Next, the case where the engine 1 is started from the state S2 in FIG. 5A when the engine 1 is in a low cold state will be described. When the engine 1 is in a low cold state, the second temperature sensitive biasing member 94 has not reached the shape recovery temperature, but the first temperature sensitive biasing member 93 has reached the shape recovery temperature. That is, the fact that the engine 1 is in a low cold state at the time of starting means that the engine 1 is shortly after the start of the engine 1 is stopped, and usually the cooling water temperature in the slow-change greenhouse 91f is at least extremely cold. The reference temperature Tb is exceeded. Therefore, not only the urging member 92 but also the first temperature-sensitive urging member 93 generates an urging force, and in this state, the first temperature-sensitive urging member 93 has a larger urging force than the urging force of the urging member 92. Since the valve body 91 is biased to the open state, the valve body 91 of the on-off valve mechanism 9 is located in the open state, and the short-circuit passage 232e is open. At this time, the heater inflow port 7a is closed by the accommodating portion 91c of the valve body 91, and therefore the heater path and the bypass path are closed. On the other hand, since the cooling water temperature has not reached the path opening temperature, the thermostat 7 is in a state of closing the radiator path.

  When the engine 1 is operated, the crank pulley 55 is rotated to operate the water pump 8, and all of the coolant discharged from the water pump 8 is the base end portion of the first cooling passage 232 a of the water jacket 20. However, since the short-circuit path 232e is open, the internal pressure of the short-circuit path 232e is reduced by the nearest water pump 8, and each path of the heater path, the bypass path, and the radiator path Therefore, the entire amount of the cooling water is introduced into the thermostat housing 71 through the short-circuit passage 232e and sucked into the water pump 8 again. That is, the cooling water circulates through the shortcut path including the short-circuit path 232e, so that the cooling water in the water jacket 20 stays. For this reason, the cooling water in the water jacket 20 can be warmed early, and early warm-up can be realized to reduce CO, HC, and the like due to incomplete combustion, thereby improving emissions.

  When the cooling water circulates and circulates through the shortcut path and the cooling water temperature reaches the low cold reference temperature Ts, the second temperature-sensitive urging member 94 generates an urging force. Since the urging force of the second temperature-sensitive urging member 94 and the urging member 92 is larger than the urging force of the first temperature-sensitive urging member 93, the valve body 91 is displaced from the open state to the closed state, As a result, the short-circuit path 232e, that is, the shortcut path is closed. When the valve body 91 is closed, the heater inflow port 7a closed by the valve body 91 is opened, and the heater path and the bypass path are opened.

  In this state, the heater unit 6 can be operated, and since the cooling water having a low cold reference temperature Ts flows into the heater unit 6, warm air having a relatively high and stable temperature is sent into the vehicle interior. And the passenger's heating requirement can be satisfied as much as possible.

  As described above, when the engine 1 is in the low cold state at the time of start-up, as shown in FIG. 5C, while the engine 1 is in the low cold state, the water path is opened by opening the shortcut path. While retaining the cooling water in the jacket 20 and closing the heater path, the temperature of the cooling water can be efficiently warmed up and early warm-up can be achieved, and the emission performance can be improved. Then, after the engine 1 shifts to the warm state, by closing the shortcut path, it is possible to circulate the cooling water at the normal flow rate in the water jacket 20 and open the heater path to blow the heater unit 6. It is in a state. As a result, when the heater unit 6 is operated, a relatively high and stable warm air is sent into the passenger compartment, and thereby, the heating performance can be achieved so as to meet the demands of the occupant as much as possible.

  Next, the case where the engine 1 is started from the state S3 in FIG. 5A when the engine 1 is in a warm state will be described. When the engine 1 is in a warm state, the first and second temperature-sensitive urging members 93 and 94 both reach the shape recovery temperature. In this state, the urging member 92 and the second temperature-sensitive urging member Since the urging force by 94 is larger than the urging force by the first temperature-sensitive urging member 93, the valve body 91 is located in the closed state by these combined urging forces, and the short-circuit passage 232e is in an open state. . At this time, the heater inflow port 7a is opened by the accommodating portion 91c of the valve body 91, and thus the heater path and the bypass path are opened. On the other hand, since the cooling water temperature has not reached the path opening temperature, the thermostat 7 is in a state of closing the radiator path.

  In this state, since the engine 1 is sufficiently warm, there is little need for warm-up, and since the cooling water temperature is relatively high, the warm air sent into the passenger compartment by the heater unit 6 is also compared. By ensuring the normal operating state of the engine 1, the passenger's heating requirement is satisfied.

  Then, when the cooling water temperature further increases and reaches the path opening temperature To, the thermostat 7 is switched to the open state so that the radiator path is opened and the cooling water is efficiently cooled by the radiator 5. As a result, when the cooling water temperature becomes equal to or lower than the path opening temperature To, the thermostat 7 switches to the closed state and the cooling water temperature starts to rise again. The cooling water is controlled to an appropriate temperature range while repeating this operation.

  As described above, when the engine 1 is in a warm state at the time of starting, as shown in FIG. 5D, the normal flow rate, that is, the engine rotation speed, is filled in the water jacket 20 by closing the shortcut path. The cooling water having a flow rate corresponding to the refrigerant flows and the cooling water flows through the heater path and the bypass path, so that the normal operation state of the engine 1 is ensured.

  As described above, according to the cooling device for the engine 1 of this embodiment, the temperature of the engine 1 is mechanically determined based on the coolant temperature, not electrically, and the vehicle that is assumed based on the engine temperature is assumed. Depending on the room temperature, priority can be given to either one of the passenger's heating request and the early warm-up request.

  In addition, the cooling water temperature can be discriminated by effectively using the urging forces of the first and second temperature-sensitive urging members 93 and 94 having different shape recovery temperatures. The cooling water flow rate in the jacket 20 can be adjusted. Further, by adopting a thermostat 7 having a mechanical configuration, it is possible to adjust the flow rate for each path more reliably and inexpensively.

  The engine cooling apparatus described above is an embodiment of the apparatus according to the present invention, and the specific configuration and the like can be changed as appropriate without departing from the spirit of the present invention. Hereinafter, the modification is demonstrated.

  (1) In the above embodiment, the cooling water in the cylinder block 21 is configured to first flow through the exhaust side and then through the intake side. The specific configuration of the jacket 20a is not particularly limited.

  For example, as shown in FIGS. 6 and 7, in the cylinder block 21, the cooling water may be configured to first flow through the intake side and then through the exhaust side. . That is, in the cooling device according to another modification, the shape of the cylinder block is different from that of the above embodiment. This difference will be explained mainly.

  The cylinder block 121 according to the modified example employs a U-turn cooling system as in the above embodiment, but the water jacket 120a circulates around the cylinders 10A to 10D, and the partition wall 233 according to the above embodiment. It is different in that is not provided.

  Specifically, as shown in FIG. 6, the block-side water jacket 120 a is configured such that the front side portion of the cylinder block 21 from the cooling water inflow port 231, in other words, the intake side portion of the cylinder block 121 extends along the cylinder row direction. An intake side cooling passage 332a extending to the other end side (left side in the example) of the block 121, and a conversion extending to the rear side of the other end portion (left side portion in the example) of the cylinder block 121 in communication with the intake side cooling passage 332a. A cooling passage 332b and a rear end portion of the cylinder block 121 communicating with the conversion cooling passage 332b, in other words, an exhaust-side side portion of the cylinder block 121 along one end of the cylinder block 121 in the longitudinal direction along the cylinder row direction ( Exhaust side cooling passage 332c extending to the right side in the example shown in FIG. One side of the block 121 in the longitudinal direction (right side in the illustrated example) is provided with a communication cooling passage 332d extending forward, and an intake cooling passage 332a, a conversion cooling passage 332b, an exhaust side cooling passage 332c, and a communication cooling passage 332d in this order. Cooling water is distributed. A short-circuit passage 332e similar to that of the above-described embodiment is opened at the base end portion of the intake-side cooling passage 332a, and a shortcut route is configured through the short-circuit passage 332e.

  In this case, the cooling water inflow port 331 is also formed with the downstream end inclined to the inside of the cylinder block 121 as clearly shown in FIG. 7, so that the cooling water can be easily introduced into the intake side cooling passage 332a. ing.

  Even if comprised in this way, both can be made compatible by giving priority to either one of a passenger | crew's heating request | requirement and an early warm-up request | requirement. In addition, since the block-side water jacket 120a makes one round around the cylinders 10A to 10D, a part of the cooling water can be circulated in the block-side water jacket 120a when the engine is in a cold state. Therefore, it is possible to efficiently perform early warm-up by actively performing heat exchange.

  (2) In the above embodiment, when the engine is in a small cold state, the cooling water is configured to stay in the water jacket 20, but is configured to circulate partially in the bypass passage, for example. It may be a thing. Even in this case, it is possible to obtain the same effect as that of the above embodiment.

  (3) In the above embodiment, the urging member 92 urges the valve body 91 in the closed state, the first temperature-sensitive urging member 93 urges the valve body 91 in the open state, and the second temperature-sensitive urging force. The member 94 is configured to urge the valve body 91 in the closed state. However, by appropriately setting the shape recovery temperature and the urging force, the member 94 operates in the same manner as the operation of the valve body 91 other than these combinations. It is also possible to make it.

  (4) In the above embodiment, the oil cooler 50 and the like are disposed in the bypass pipe 17, but these can be omitted as appropriate. In this case, since the cooling water in the water jacket 20 is circulated by the bypass pipe 17 with little heat exchange, the cooling water temperature can be increased efficiently.

  (5) In the above embodiment, when the engine in the extremely cold state is started, even if the cooling water temperature exceeds the extremely cold reference temperature Tb, the valve body 91 is not switched to the open state, and the engine is kept warm. The valve body 91 is controlled to be opened and closed in the intermediate state. For example, the volume of the slow change greenhouse 91f is reduced, or the slow change greenhouse 91f is provided with a through hole communicating with the outside. The delay with respect to the temperature change of the cooling water in the variable temperature chamber 91f may be set short, and thereby the valve body 91 may be switched to the open state on the high temperature side in the cold state of the engine.

1 is a schematic perspective view of an engine cooling device according to the present invention. It is explanatory drawing which shows the same apparatus typically. It is principal part sectional drawing which shows the flow-path adjustment mechanism in case a valve body exists in a closed state. It is principal part sectional drawing which shows the flow-path adjustment mechanism in case a valve body exists in an open state. It is explanatory drawing which shows the time change etc. of cooling water temperature. It is explanatory drawing which shows typically the modification of the cooling device of the engine which concerns on this invention. It is principal part sectional drawing which shows the flow-path adjustment mechanism of the modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Engine main body 5 Radiator 6 Heater unit 7 Thermostat 9 On-off valve mechanism 10A-10D Each cylinder 18 Pressure regulating pipe 20 Water jacket 20a Block side water jacket 20b Head side water jacket 21 Cylinder block 22 Cylinder head 50 Oil cooler (Heat exchange) vessel)
52 ATF Warmer (Heat Exchanger)
71 Thermostat housing 81 Water pump housing 91 Valve body 91f Slowly changing greenhouse 92 Energizing member 93 First temperature sensing energizing member 94 Second temperature sensing energizing member 231 Cooling water inflow port 232e Short circuit passage

Claims (6)

A radiator path that circulates a cooling fluid between a water jacket and a radiator in the engine at a predetermined path opening temperature or higher, and a heater unit for heating the water jacket and the vehicle interior by overlapping a part of the radiator path and the path. A heater path that circulates the cooling fluid between the water pump, a water pump that is disposed in an overlapping portion of the above paths and forcibly circulates the cooling water, and a shortcut that short-circuits the upstream and downstream paths of the water pump A path, and an on-off valve mechanism that adjusts the flow rate of the cooling fluid flowing into the water jacket by opening and closing the shortcut path,
The on-off valve mechanism is formed of a valve body that opens and closes the shortcut path, an elastic member that biases the valve body in a closing direction, and a shape memory alloy that attaches the valve body in the opening direction at a predetermined shape recovery temperature or higher. A first shape memory alloy spring that biases and a second shape memory alloy spring that is made of a shape memory alloy and biases the valve body in a closing direction at a predetermined shape recovery temperature or higher,
The shape recovery temperature of the first shape memory alloy spring is set to a predetermined first switching temperature lower than the path opening temperature, while the shape recovery temperature of the second shape memory alloy spring is set to the path opening temperature. Is set at a predetermined second switching temperature that is lower than the first switching temperature and higher than the first switching temperature, and is disposed at a position that can immediately respond to a change in the temperature of the cooling water flowing through each path,
When the cooling water temperature is lower than the first switching temperature due to the urging force of the urging force by the elastic member and the temperature condition urging force by the first and second shape memory alloy springs, the on-off valve mechanism The valve body is urged to the closed state, and when the cooling water temperature is equal to or higher than the first switching temperature and lower than the second switching temperature, the valve body is urged to the open state, and the cooling water temperature is switched to the second switching temperature. An engine cooling device configured to bias the valve body to a closed state when the temperature is equal to or higher than a temperature.   The valve body has a slow change greenhouse in which the temperature of the cooling fluid existing inside the temperature change of the cooling fluid flowing outside has a predetermined delay, and the first shape memory is stored in the slow change greenhouse. 2. The engine cooling apparatus according to claim 1, wherein an alloy spring is provided.   The on-off valve mechanism is housed in a housing disposed adjacent to the water pump, and an internal space of the housing is open at one end of a heater inflow port for introducing cooling water sent out from the heater unit. The body is housed in the housing in such a manner that the opening of the heater inflow port is closed in the open state and the opening of the port is opened in the closed state. Engine cooling system.   The water pump is configured as a centrifugal water pump and is disposed upstream of the water jacket and downstream of the housing, and the internal space of the housing is connected to the water jacket through a shortcut passage that forms a shortcut path. One end of a radiator inflow port that communicates with the upstream end and introduces cooling water sent out from the radiator opens, and a thermostat that opens and closes the radiator path based on the cooling water temperature is disposed in the housing. 4. The engine cooling apparatus according to claim 3, wherein the engine cooling apparatus is provided.   A sub-circulation path that bypasses the radiator and the heater unit and connects the cooling fluid inlet / outlet of the water jacket is further provided, and an oil heat exchanger that exchanges heat between the cooling fluid and engine oil is disposed in the sub-circulation path. The engine cooling device according to any one of claims 1 to 4, wherein the engine cooling device is provided.   6. The engine according to claim 5, wherein a heat exchanger bypass for bypassing the oil heat exchanger is provided in the sub-circulation path, and a pressure relief valve is disposed in the heat exchanger bypass. Cooling system.

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