JP2014047764A - Cooling device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize an opening/closing switching temperature of each of thermo-valves with respect to a cooling device including the plurality of thermo-valves.SOLUTION: A two-system cooling device in which a head-side water jacket 21 and a block-side water jacket 31 are independent from each other, is provided with a main thermo-valve 81 switched from a closed state to an opened state by increase of a cooling water temperature to supply cooling water to a radiator 6, a block thermo-valve 82 switched from a closed state to an opened state by increase of a cooling water temperature to supply cooling water to the block-side water jacket 31, and a warm water cut valve 83 switched from an opened state to a closed state by increase of a cooling water temperature to stop the supply of cooling water to a throttle body 7. A switching temperature of the warm water cut valve 83 is higher than a switching temperature of the block thermo-valve 82 and lower than a switching temperature of the main thermo-valve 81.

Description

  The present invention relates to a cooling device for an internal combustion engine. In particular, the present invention relates to an improvement of a cooling device that includes a plurality of thermo valves in a cooling water circulation circuit and that switches the flow path of the cooling water by opening and closing operations of these thermo valves.

  Conventionally, in an automobile engine or the like, when the outside air temperature is low, such as in winter, the moisture contained in the intake air freezes (icing) around the throttle valve, and the throttle valve is in the intake pipe inner surface (throttle body). There is a possibility that it freezes and adheres to the inner surface of the intake passage.

  In order to prevent or eliminate freezing and sticking of the throttle valve, a cooling water passage is formed in the throttle body, and when the engine is cold started, the throttle body is heated by flowing the engine cooling water through the cooling water passage. (See, for example, Patent Document 1 and Patent Document 2 below). In addition, when the temperature of the engine cooling water exceeds a predetermined temperature, the supply of the cooling water to the cooling water passage in the throttle body is stopped. The supply of cooling water is stopped by closing a hot water cut valve provided on the upstream side of the cooling water passage in the throttle body.

Japanese Patent Laid-Open No. 3-78537 JP 2008-106625 A JP 2009-74381A

  By the way, as disclosed in Patent Document 3, a water jacket for an engine cylinder head (hereinafter also referred to as “head side water jacket”) and a water jacket for a cylinder block (hereinafter referred to as “block side water jacket”). In some cases, an engine cooling device (generally referred to as a “two-system cooling device”) in which cooling water is circulated in parallel has been proposed.

  In this type of cooling device, for example, when the engine is cold started, the supply of the cooling water to the block-side water jacket is stopped and the cooling water is supplied to the head-side water jacket. This makes it possible to quickly increase the temperature of the cylinder block while suppressing an excessive increase in the temperature of the cylinder head, and to reduce the friction loss at various points in the engine within a short period after the engine is started. The fuel consumption rate can be improved.

  Further, as an example of the two-system cooling device, two thermo valves are provided, and the flow path of the cooling water is switched by opening and closing the thermo valves.

  Specifically, a main thermo valve and a block thermo valve are provided. The main thermo valve can be switched between a closed state in which the cooling water derived from the engine body flows to bypass the radiator and an open state in which the coolant flows to the radiator. On the other hand, the block thermo valve can be switched between a closed state in which the cooling water discharged from the water pump does not flow to the block side water jacket, but flows to the head side water jacket, and an open state to flow to both water jackets. It has become. When the engine is cold-started, both thermo valves are closed, and the engine is warmed up early by preventing cooling water from flowing through the radiator and the block-side water jacket. Further, after the warm-up of the engine is completed, both the thermo valves are opened, and cooling water is supplied to the radiator and the block-side water jacket so that the radiator releases heat and the cylinder block is cooled. Thereby, optimization of the temperature of a cylinder head and a cylinder block is aimed at.

  In addition, the general thermo valve used for the cooling device mentioned above has the temperature sensing cylinder arrange | positioned in cooling water. A thermo wax that expands and contracts in accordance with the heat of the cooling water transmitted through the wall of the temperature sensing cylinder is accommodated in the temperature sensing cylinder. And according to the expansion | swelling and shrinkage | contraction of this thermowax, it becomes the structure which can switch a thermo valve between the said closed state and an open state.

  However, when the above-described hot water cut valve (thermo valve provided on the upstream side of the cooling water passage in the throttle body) is applied to such a two-system cooling device, there is a possibility of causing the following problems. is there.

  First, at the time of cold start of the engine, both the main thermo valve and the block thermo valve are in the closed state. After that, when the cooling water temperature rises and the hot water cut valve switches from the open state to the closed state, if the main thermo valve and the block thermo valve are kept closed, the pressure loss in the water jacket inside the engine Will rise. That is, since substantially the entire amount of cooling water discharged from the water pump flows only into the head side water jacket, the pressure loss in the head side water jacket increases. In such a situation, the difference between the upstream pressure and the downstream pressure of the main thermo-valve arranged between the cooling water outlet side of the head side water jacket and the suction port side of the water pump becomes large. The main thermo valve may be forcibly opened due to the difference. When the main thermo valve is forcibly opened in this way, the relatively low temperature cooling water staying in the radiator circulates in the cooling water circulation circuit, and this cooling water is, for example, a heater (vehicle The heat exchange amount in the heater (the amount of heat exchange between the cooling water and the vehicle interior air) may be reduced, resulting in insufficient heating capacity in the vehicle interior. There is.

  In addition, when the warm-up of the engine is completed and both the main thermo valve and the block thermo valve are in the open state, and the open state of the hot water cut valve is still maintained, the cooling discharged from the water pump A part of the water flows into the cooling water passage in the throttle body. In such a situation, it becomes impossible to secure a sufficient amount of cooling water flowing to the radiator, leading to a situation in which the amount of heat dissipated in the radiator is insufficient and the temperature of the cooling water tends to be higher than the appropriate temperature. . As a result, there is a possibility that the temperature of the cylinder head and the cylinder block cannot be optimized.

  The present invention has been made in view of the above points, and an object of the present invention is to optimize the switching temperature of each thermo valve for a cooling device including a plurality of thermo valves.

  The solution means of the present invention for achieving the above object is based on a cooling device for an internal combustion engine provided with a hot water cut valve, a block thermo valve, and a main thermo valve. The hot water cut valve supplies cooling water to the cooling water passage of the throttle body when the internal combustion engine is cold, and stops supplying the cooling water to the cooling water passage of the throttle body after the internal combustion engine is warmed up. The block thermo valve supplies cooling water to the cooling water passage of the cylinder head when the internal combustion engine is cold, and supplies cooling water to the cooling water passage of the cylinder head and the cooling water passage of the cylinder block after the internal combustion engine is warmed up. To do. The main thermo valve stops the flow of cooling water between the radiator and the internal combustion engine body when the internal combustion engine is cold, and circulates the cooling water between the radiator and the internal combustion engine body after the internal combustion engine is warmed up. Let Then, the cooling that the block thermo valve shifts from the state of supplying cooling water to the cooling water passage of the cylinder head to the state of supplying cooling water to the cooling water passage of the cylinder head and the cooling water passage of the cylinder block, respectively. The state in which the hot water cut valve stops supplying the cooling water to the cooling water passage of the throttle body from the state of supplying the cooling water to the cooling water passage of the throttle body from the block thermo switching temperature that is the water temperature Set the hot water cut switching temperature that is the cooling water temperature to shift to. Further, from the state in which the main thermo valve stops the flow of the cooling water between the radiator and the internal combustion engine body from the hot water cut switching temperature, the cooling water is supplied between the radiator and the internal combustion engine body. The main thermo switching temperature, which is the cooling water temperature that shifts to the circulating state, is set higher.

  Here, in each valve, the cooling water temperature at which the state transitions is the cooling water temperature at which the operation of the valve starts, or the valve opening is set to a predetermined opening (for example, 30% opening). Etc.) is the cooling water temperature.

  According to this specific matter, as the cooling water temperature rises from when the internal combustion engine is cold started, the block thermo valve first supplies the cooling water to the cooling water passage of the cylinder head from the state where the cooling water is supplied to the cylinder head. The state shifts to a state in which cooling water is supplied to the passage and the cooling water passage of the cylinder block. Thereafter, the hot water cut valve shifts from a state where the cooling water is supplied to the cooling water passage of the throttle body to a state where the supply of the cooling water to the cooling water passage of the throttle body is stopped. Thereafter, the main thermo valve shifts from a state in which the flow of the cooling water between the radiator and the internal combustion engine body is stopped to a state in which the cooling water is circulated between the radiator and the internal combustion engine body.

  For this reason, when the hot water cut valve is in a state where the supply of the cooling water to the cooling water passage of the throttle body is stopped, the block thermo valve has already been turned into the cooling water passage of the cylinder head and the cooling water of the cylinder block. It has shifted to a state in which cooling water is supplied to each passage. In other words, with the circulating coolant flowing through the coolant passage of the cylinder head and the coolant passage of the cylinder block, the hot water cut valve stops supplying the coolant to the coolant passage of the throttle body. Will be migrated. For this reason, even if the supply of the cooling water to the cooling water passage of the throttle body is stopped, the pressure loss inside the internal combustion engine main body is prevented from significantly increasing, and the upstream side pressure and the downstream side of the main thermo valve are suppressed. The difference from the side pressure is prevented from becoming large. As a result, a situation in which the main thermo valve is forcibly opened due to this pressure difference can be avoided.

  In addition, when the temperature of the cooling water rises and the main thermo valve circulates the cooling water between the radiator and the internal combustion engine body, the hot water cut valve has already been connected to the cooling water passage of the throttle body. The supply of cooling water to is stopped. Therefore, a part of the circulating cooling water does not flow into the cooling water passage of the throttle body, and when the main thermo valve shifts to a state in which the cooling water is circulated between the radiator and the internal combustion engine body, the radiator It is possible to secure a sufficient amount of cooling water flowing in the tank. Therefore, a sufficient amount of heat is dissipated from the cooling water in the radiator, and the temperature of the cooling water can be maintained at an appropriate temperature.

  Specific connection forms of the devices constituting the cooling device include the following. First, the block thermo valve is connected to a cooling water inlet into which cooling water discharged from a water pump is introduced, a first cooling water outlet communicating with the cooling water passage of the cylinder block, and a cooling water inlet of the hot water cut valve. A second cooling water outlet is provided. When the block thermo valve supplies cooling water to the cooling water passage of the cylinder head, the first cooling water outlet is closed, and the cooling water passage of the cylinder head and the cooling water passage of the cylinder block are respectively closed. In a state where the cooling water is supplied, the first cooling water outlet is opened and the cooling water is supplied to the cooling water passage of the cylinder head, and the cooling water passage of the cylinder head and the cooling water passage of the cylinder block The cooling water inlet and the second cooling water outlet are in communication with each other in any state where the cooling water is supplied.

  A first cooling water inlet communicating with the cooling water outlet of the radiator communicating with the cooling water outlet of the cooling water passage of the cylinder head and the cooling water outlet of the cooling water passage of the cylinder block; A second cooling water inlet communicating with the cooling water passage of the throttle body and a cooling water outlet communicating with the suction port of the water pump are provided. The main thermo valve closes the first cooling water inlet in a state where the flow of the cooling water between the radiator and the internal combustion engine body is stopped, and cools between the radiator and the internal combustion engine body. In a state where water is circulated, the first cooling water inlet is opened so that the cooling water outlet of the radiator and the suction port of the water pump communicate with each other.

  In these circuit configurations, the main thermo valve stops the flow of the cooling water between the radiator and the internal combustion engine body, and the block thermo valve supplies the cooling water to the cooling water passage of the cylinder head. When the hot water cut valve shifts from the state of supplying cooling water to the cooling water passage of the throttle body to the state of stopping the supply of cooling water to the cooling water passage of the throttle body, the main thermo valve There is a possibility that the difference between the upstream pressure and the downstream pressure increases and the main thermo valve is forcibly opened. The main thermo valve circulates cooling water between the radiator and the internal combustion engine body, and the block thermo valve supplies cooling water to the cooling water passage of the cylinder head and the cooling water passage of the cylinder block, respectively. If the hot water cut valve is in a state where it is in a state of supplying cooling water to the cooling water passage of the throttle body, it will not be possible to secure a sufficient amount of cooling water flowing to the radiator, There is a risk that the amount of heat dissipated in the cooling water at the radiator will be insufficient. For such a circuit configuration, as described above, by appropriately setting the block thermo switching temperature, the hot water cut switching temperature, and the main thermo switching temperature, it is possible to solve these problems.

  In the present invention, by optimizing the switching temperature of each of the hot water cut valve, the block thermo valve, and the main thermo valve, the main thermo valve can be prevented from being forcibly opened. The temperature can be maintained at an appropriate temperature.

It is a schematic block diagram which shows the cooling water circulation circuit of the cooling device which concerns on embodiment. It is a figure for demonstrating each switching temperature of a block thermo valve, a warm water cut valve, and a main thermo valve. It is a cooling water circulation circuit diagram which shows the flow of the cooling water at the time of the cold start of an engine. It is a cooling water circulation circuit diagram which shows the flow of the cooling water when the cooling water temperature reaches the block thermo valve opening temperature. It is a cooling water circulation circuit diagram which shows the flow of the cooling water when the cooling water temperature reaches the hot water cut valve closing temperature. It is a cooling water circulation circuit diagram which shows the flow of the cooling water when the cooling water temperature reaches the main thermo valve opening temperature.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where this invention is applied as a cooling device of a motor vehicle engine.

-Schematic configuration of cooling device-
FIG. 1 is a schematic configuration diagram illustrating a cooling water circulation circuit of the cooling device according to the present embodiment. As shown in FIG. 1, the cooling device is formed in a cooling water passage 21 (hereinafter referred to as a head-side water jacket) formed in a cylinder head 2 of an engine (internal combustion engine) 1 and in a cylinder block 3. The cooling water passage 31 (hereinafter referred to as a block-side water jacket) is configured as a two-system cooling device independent of each other. The engine 1 is a gasoline engine or a diesel engine mounted on a conventional vehicle (a vehicle equipped with only an engine as a driving force source) or a hybrid vehicle (a vehicle equipped with an engine and an electric motor as a driving force source). It is configured.

  As shown in FIG. 1, the cooling device includes a water pump (W / P) 4, a heater 5, a radiator 6, a throttle body 7, a main thermo valve 81, a block thermo valve 82, a hot water cut valve 83, and the like as main devices. A cooling water circulation circuit 10 for circulating cooling water (for example, LLC: Long Life Coolant) in these devices is provided.

  The water pump 4 is a mechanical water pump that is connected to a crankshaft that is an output shaft of the engine 1 and is driven by the rotational driving force of the crankshaft. The water pump 4 may be an electric pump.

  The discharge port 4a of the water pump 4 is connected to the cooling water inlet 21a of the head side water jacket 21 of the engine 1 via the head inlet passage 11a. The discharge port 4a of the water pump 4 is connected to the cooling water inlet 31a of the block-side water jacket 31 of the engine 1 via the block inlet passage 11b. The block thermo valve 82 is disposed on the cooling water inlet side of the block side water jacket 31 (inside the cylinder block 3), and the cooling water inlet 82 a of the block thermo valve 82 cools the block side water jacket 31. It is a water inlet 31a.

  The block thermo valve 82 may be arranged outside the cylinder block 3. Further, the water pump 4 may be connected to the water jackets 21 and 31 via pipes, or integrated into the cylinder block 3, and the cooling water discharge side communicates with the water jackets 21 and 31. It may be configured.

  The block thermo valve 82 includes the cooling water inlet 82a and cooling water outlets 82b and 82c. As described above, the cooling water inlet 82a is connected to the discharge port 4a of the water pump 4 through the block inlet passage 11b. One cooling water outlet (first cooling water outlet in the present invention) 82 b is connected to the block-side water jacket 31. The other cooling water outlet (second cooling water outlet in the present invention) 82 c is connected to the cooling water inlet 83 a of the hot water cut valve 83.

  The block thermo valve 82 is in a closed state when the engine 1 is cold-started, so that the cooling water flowing in from the block inlet passage 11b does not flow to the block-side water jacket 31 but flows only to the hot water cut valve 83 side. Yes. That is, the block thermo valve 82 is provided with a passage that always connects the block inlet passage 11b and the hot water cut valve 83, and the block thermo valve 82 is in a closed state (cooling water is supplied to the block-side water jacket 31). Even if it is not in the state, the coolant is allowed to flow to the hot water cut valve 83 side. In such a closed state of the block thermo valve 82, the cooling water flows only in the head side water jacket 21 inside the engine body (internal combustion engine body) 1a.

  On the other hand, the block thermo valve 82 is configured to flow the cooling water flowing in from the block inlet passage 11b to the block-side water jacket 31 when the temperature of the cooling water reaches a predetermined temperature and is opened. In this case, in the interior of the engine main body 1a, the cooling water flows through both the head-side water jacket 21 and the block-side water jacket 31.

  Specifically, the block thermo valve 82 is a valve device that includes a heat sensitive portion that gives displacement to the valve body, and operates by expansion / contraction of the thermo wax of the temperature sensitive portion, and when the cooling water temperature is relatively low, In the closed state, the communication path on the block-side water jacket 31 side is closed so that cooling water does not flow through the block-side water jacket 31. On the other hand, after the warm-up of the engine 1 is completed, that is, when the cooling water temperature is relatively high, the open state is opened according to the cooling water temperature, and the communication path on the block side water jacket 31 side is opened. Cooling water is allowed to flow through the water jacket 31. Such a temperature-sensitive valve opening / closing mechanism is publicly known (see, for example, Japanese Patent Application Laid-Open No. 2012-117485 and Japanese Patent Application Laid-Open No. 2012-102690), and a description thereof is omitted here. The same applies to a main thermo valve 81 and a hot water cut valve 83 which will be described later. The cooling water temperature at which the block thermo valve 82 shifts from the closed state to the open state (block thermo switching temperature in the present invention) will be described later.

  The cooling water outlet 21b of the head side water jacket 21 is connected to the cooling water inlet 5a of the heater 5 and the cooling water inlet 6a of the radiator 6 via the head outlet passage 11c. The cooling water outlet 31b of the block-side water jacket 31 is connected to the head outlet passage 11c through a block outlet passage 11d. The block outlet passage 11d may be provided outside the engine body 1a or may be formed inside the engine body 1a.

  The heater 5 is a heat exchanger for heating the passenger compartment using the heat of the cooling water, and is disposed facing the air duct of the air conditioner. In other words, when the vehicle interior is heated (when the heater is ON), the conditioned air flowing in the air duct is passed through the heater 5 (heater core) and supplied as warm air to the vehicle interior, while at other times (for example, during cooling) When the heater is turned off, the conditioned air bypasses the heater 5.

  An oil cooler 9 is branched and connected to the flow path downstream of the cooling water outlet 5 b of the heater 5. The oil cooler 9 is, for example, a heat exchanger for adjusting the temperature of transmission hydraulic fluid (ATF; Automatic Transmission Fluid), and functions not only as an oil cooler (when the oil temperature is high) but also as an oil warmer. The function (when the oil temperature is low) is also fulfilled.

  In addition, the radiator 6 performs heat exchange between the cooling water and the outside air (running wind or air blown by driving a cooling fan), and cools the cooling water by releasing the heat of the cooling water to the outside air. ing. A reserve tank 61 is connected in parallel to the radiator 6.

  The cooling water outlet 5b of the heater 5 and the cooling water outlet 6b of the radiator 6 are connected to cooling water inlets 81a and 81b of the main thermo valve 81, respectively. The cooling water outlet 81 d of the main thermo valve 81 is connected to the suction port 4 b of the water pump 4.

  Specifically, the main thermo valve 81 includes the cooling water inlets 81a, 81b, 81c and the cooling water outlet 81d. As described above, the cooling water inlet 81a is connected to the cooling water outlet 5b of the heater 5 at the cooling water inlet ( The first cooling water inlet 81b referred to in the present invention is connected to the cooling water outlet 6b of the radiator 6. The cooling water inlet (second cooling water inlet referred to in the present invention) 81 c is connected to a cooling water outlet 7 b that is a downstream end of a cooling water passage formed inside the throttle body 7. The throttle body 7 is disposed in the intake system of the engine 1 and includes an electronically controlled throttle valve that adjusts the amount of intake air, and a throttle motor that adjusts the opening of the throttle valve (both not shown). I have.

  The main thermo valve 81 is closed when the engine 1 is cold-started, and shuts off the cooling water inlet 81b (connection port to the radiator 6) and the cooling water outlet 81d. That is, the flow of the cooling water between the radiator 6 and the engine 1 is stopped. The main thermo valve 81 allows the cooling water inlet 81b and the cooling water outlet 81d to communicate with each other when the temperature of the cooling water reaches a predetermined temperature and is opened. That is, the cooling water is circulated between the radiator 6 and the engine body 1a.

  Specifically, the main thermo valve 81 is a valve device that includes a heat-sensitive portion that gives displacement to the valve body, and operates by expansion and contraction of the thermo-wax of the temperature-sensitive portion, and when the cooling water temperature is relatively low, In a closed state, the cooling water passage between the radiator 6 and the water pump 4 is blocked (between the cooling water inlet 81b and the cooling water outlet 81d) so that the cooling water does not flow into the radiator 6. To do. On the other hand, after the warm-up of the engine 1 is completed, that is, when the cooling water temperature is relatively high, the engine 1 is opened according to the cooling water temperature, and the cooling water inlet 81b and the cooling water outlet 81d communicate with each other. Allow some of the cooling water to flow through. The cooling water temperature at which the main thermo valve 81 shifts from the closed state to the open state (main thermo switching temperature in the present invention) will be described later.

  The cooling water inlet 81a (connection port to the heater 5) of the main thermo valve 81 and the cooling water outlet 81d are always in communication with each other, and the cooling water flowing from the cooling water inlet 81a toward the cooling water outlet 81d It comes in contact with the temperature sensitive part. Further, the cooling water inlet 81c (connection port to the throttle body 7) of the main thermo valve 81 and the cooling water outlet 81d are always in communication.

  The hot water cut valve 83 can be switched between a state in which cooling water is supplied to a cooling water passage formed in the throttle body 7 and a state in which the supply of cooling water is stopped. That is, in this hot water cut valve 83, the cooling water inlet 83a is connected to the cooling water outlet 82c of the block thermo valve 82, and the cooling water outlet 83b is a cooling that is the upstream end of the cooling water passage in the throttle body 7. It is connected to the water inlet 7a. Further, as described above, the cooling water outlet 7 b which is the downstream end of the cooling water passage in the throttle body 7 is connected to the cooling water inlet 81 c of the main thermo valve 81.

  The hot water cut valve 83 is opened when the engine 1 is cold started, and the cooling water discharged from the water pump 4 passes through the block inlet passage 11b and the block thermo valve 82 to the cooling water passage in the throttle body 7. It is supposed to flow. The cooling water is supplied to the cooling water passage in the throttle body 7 because the block inlet passage 11b and the hot water cut valve 83 are always in communication with each other even when the block thermo valve 82 is closed. It is possible.

  Further, the hot water cut valve 83 blocks the flow of the cooling water to the cooling water passage in the throttle body 7 when the temperature of the cooling water reaches a predetermined temperature and becomes a closed state. The cooling water temperature at which the hot water cut valve 83 shifts from the open state to the closed state (hot water cut switching temperature in the present invention) will be described later.

  Also, the hot water cut valve 83 is a valve device that includes a heat sensitive portion that gives displacement to the valve body and operates by the expansion and contraction of the thermo wax in the temperature sensitive portion, similarly to each of the thermo valves 81 and 83 described above. When the cooling water temperature is relatively low, the block inlet passage 11b and the cooling water passage in the throttle body 7 are brought into communication with each other, and the cooling water flows through the cooling water passage in the throttle body 7. On the other hand, after the warm-up of the engine 1 is completed, that is, when the coolant temperature is relatively high, the block 1 is closed according to the coolant temperature, and the block inlet passage 11b and the coolant passage in the throttle body 7 are shut off. Thus, the cooling water is prevented from flowing into the cooling water passage in the throttle body 7. The cooling water temperature at which this hot water cut valve 83 shifts from the open state to the closed state will be described later.

  Thus, as an outline of the cooling water circulation circuit 10 of the cooling device, the cooling water discharge side of the water pump 4 is branched into the head side water jacket 21 and the block side water jacket 31, and the block thermo valve on the block side water jacket 31 side. 82 is provided. Further, the outlet sides of the head side water jacket 21 and the block side water jacket 31 are merged and then branched into a flow path on the heater 5 side and a flow path on the radiator 6 side, each connected to the main thermo valve 81. Yes. Further, the outlet side of the main thermo valve 81 is connected to the suction side of the water pump 4. Further, a hot water cut valve 83 is connected to the block thermo valve 82, an outlet side of the hot water cut valve 83 is connected to the throttle body 7, and an outlet side of the throttle body 7 is connected to the main thermo valve 81. It has become.

-Opening / closing switching temperature of each thermo valve-
Next, opening / closing switching temperatures in the block thermo valve 82, the hot water cut valve 83, and the main thermo valve 81 will be described.

  As shown in FIG. 2, the open / close switching temperature (block thermo switching temperature) of the block thermo valve 82 is set to α. That is, when the cooling water temperature reaches α, the block thermo valve 82 is switched from the closed state to the open state. Specifically, the temperature α is set to a value in the range of 75 ° C. or more and less than 79 ° C. For example, it is set to 78 ° C.

  The open / close switching temperature (warm water cut switching temperature) of the hot water cut valve 83 is set to β. That is, when the cooling water temperature reaches β, the hot water cut valve 83 is switched from the open state to the closed state. Specifically, the temperature β is set to a value in the range of 79 ° C. or more and less than 81 ° C. For example, it is set to 80 ° C.

  Further, the open / close switching temperature (main thermo switching temperature) of the main thermo valve 81 is set to γ. That is, when the cooling water temperature reaches γ, the main thermo valve 81 is switched from the closed state to the open state. Specifically, the temperature γ is set to a value in the range of 81 ° C. or more and less than 85 ° C. For example, it is set to 82 ° C.

  Each of the above temperatures is not limited to this, and can be set as appropriate.

  Further, as specific means for making the switching temperatures of the valves 81, 82, 83 different from each other, the type of the thermo wax is made different from each other, or the biasing force of the spring that restricts the displacement of the valve body May be different from each other, or the heat sensitive parts may have different configurations. In addition, the means for making the opening / closing switching temperatures of the valves 81, 82, 83 different from each other is not limited to these.

  In this way, the open / close switching temperature (warm water cut switching temperature) β of the hot water cut valve 83 is set higher than the open / close switching temperature (block thermo switching temperature) α of the block thermo valve 82, and the open / close switching temperature of the hot water cut valve 83 is set. The open / close switching temperature (main thermo switching temperature) γ of the main thermo valve 81 is set higher than β. In other words, the open / close switching temperature β of the hot water cut valve 83 is set to be higher than the open / close switching temperature α of the block thermo valve 82 and lower than the open / close switching temperature γ of the main thermo valve 81.

  For this reason, when the engine 1 is cold started, the block thermo valve 82 is closed, the hot water cut valve 83 is open, and the main thermo valve 81 is closed, and then the temperature of the cooling water rises. First, the block thermo valve 82 is switched from the closed state to the open state, then the hot water cut valve 83 is switched from the open state to the closed state, and then the main thermo valve 81 is switched from the closed state to the open state. It will be.

−Cooling water circulation operation−
Next, the cooling water circulation operation in the cooling device configured as described above will be described. In the following, the cooling water circulation operation when the engine 1 is cold started, the cooling water circulation operation when the temperature of the cooling water reaches the open temperature of the block thermo valve 82 (block thermo switching temperature), and the temperature of the cooling water is the hot water cut valve FIG. 3 to FIG. 3 show the cooling water circulation operation when the cooling temperature reaches the closing temperature 83 (hot water cut switching temperature) of 83, and the cooling water circulation operation when the temperature of the cooling water reaches the open temperature of the main thermo valve 81 (main thermo switching temperature). 6 will be described in order. In the cooling water circulation circuit 10 shown in FIGS. 3 to 6, solid arrows indicate the passage through which the cooling water flows and the flow direction of the cooling water, and the broken lines indicate the passage through which the cooling water does not flow.

(At cold start)
First, when the engine 1 is cold started, the cooling water temperature is lower than the open temperature of the block thermo valve 82, the block thermo valve 82 is closed, the hot water cut valve 83 is open, and the main thermo valve 81 is closed. It has become. In the cooling water circulation operation in this case, as shown in FIG. 3, since the block thermo valve 82 is closed, the circulation of the cooling water in the block-side water jacket 31 is stopped (in-block water stoppage). ). By stopping the water in the block, the temperature of the cylinder block 3 can be quickly raised, so that friction loss in the engine body 1a can be reduced, and fuel consumption (fuel consumption rate) can be improved. it can. Further, since the main thermo valve 81 is also closed, the cooling water does not flow through the radiator 6, thereby allowing the engine 1 to be warmed up early. In addition, since the hot water cut valve 83 is in an open state, a part of the cooling water discharged from the water pump 4 passes through the block inlet passage 11b, the block thermo valve 82, and the hot water cut valve 83 to enter the throttle body 7. It flows into the cooling water passage. As a result, the throttle body 7 is heated, and freezing and sticking of the throttle valve can be prevented or eliminated.

(When the block thermo valve opening temperature is reached)
Thereafter, when the coolant temperature rises and the block thermo valve opening temperature is reached, the block thermo valve 82 is switched to the open state. In the cooling water circulation operation in this case, as shown in FIG. 4, since the block thermo valve 82 is opened, the circulation of the cooling water into the block side water jacket 31 is started. As a result, an excessive increase in the temperature of the cylinder block 3 is suppressed. The other cooling water flows are the same as in the cold start described above.

(When the hot water cut valve closing temperature is reached)
When the cooling water temperature further rises and reaches the hot water cut valve closing temperature, the hot water cut valve 83 is switched to the closed state. In the cooling water circulation operation in this case, as shown in FIG. 5, since the hot water cut valve 83 is closed, the supply of the cooling water to the cooling water passage in the throttle body 7 is stopped. This avoids a situation in which the intake air temperature rises due to the flow of relatively high-temperature cooling water into the cooling water passage in the throttle body 7 and the intake charging efficiency deteriorates. Performance can be secured, and responsiveness during vehicle acceleration can be secured satisfactorily. The other cooling water flow is the same as that when the block thermo valve opening temperature is reached.

(When the main thermo valve opening temperature is reached)
When the cooling water temperature further rises and reaches the main thermo valve opening temperature, the main thermo valve 81 is switched to the open state. In the cooling water circulation operation in this case, as shown in FIG. 6, since the main thermo valve 81 is opened, the circulation of the cooling water into the radiator 6 is started. Thereby, the temperature of a cooling water can be adjusted appropriately and the temperature of the cylinder head 2 and the cylinder block 3 can be optimized. The other cooling water flow is the same as that when the hot water cut valve closing temperature is reached.

-Action and effect-
As described above, in the present embodiment, as the cooling water temperature increases, the block thermo valve 82 is first switched from the closed state to the open state, and then the hot water cut valve 83 is switched from the open state to the closed state. After that, the main thermo valve 81 is switched from the closed state to the open state.

  For this reason, when the hot water cut valve 83 shifts from the open state to the closed state, the block thermo valve 82 has already been switched from the closed state to the open state. That is, the hot water cut valve 83 shifts from the open state to the closed state in a state where the cooling water discharged from the water pump 4 flows into the head side water jacket 21 and the block side water jacket 31 (divided state). For this reason, a significant increase in pressure loss inside the engine body 1a is suppressed, and the difference between the upstream pressure and the downstream pressure of the main thermo valve 81 is prevented from becoming large. As a result, a situation in which the main thermo valve 81 is forcibly opened due to this pressure difference can be avoided. For example, if the main thermo valve 81 is forcibly opened, the relatively low temperature cooling water staying in the radiator 6 circulates in the cooling water circulation circuit 10, and this cooling water is, for example, a heater. 5, the amount of heat exchange in the heater 5 (the amount of heat exchange between the cooling water and the air in the passenger compartment) may be reduced, and the heating capacity in the passenger compartment may not be sufficiently obtained. According to the present embodiment, such a situation can be avoided, and the heating capacity of the passenger compartment can be maintained high.

  Further, when the warm-up of the engine 1 is completed and the main thermo valve 81 is opened, the hot water cut valve 83 is already closed. That is, a part of the cooling water discharged from the water pump 4 flows into the cooling water passage in the throttle body 7 when the main thermo valve 81 is opened. For this reason, it becomes possible to ensure a sufficient amount of cooling water flowing to the radiator 6. Therefore, a sufficient amount of heat is dissipated from the cooling water in the radiator 6, and the temperature of the cooling water can be maintained at an appropriate temperature. As a result, the temperature of the cylinder head 2 and the cylinder block 3 can be optimized, the temperature rise of the intake air can be suppressed, and the intake charge efficiency can be maintained high.

-Other embodiments-
In the embodiment described above, the cooling water is introduced into the hot water cut valve 83 from the block inlet passage 11b through the block thermo valve 82. The present invention is not limited to this, and a passage that allows the block inlet passage 11b and the hot water cut valve 83 to communicate directly (communication without passing through the block thermo valve 82) may be provided.

  In the above embodiment, an example in which the present invention is applied to the cooling device in which the block thermo valve 82 is arranged on the cooling water inlet side of the cylinder block 3 (upstream end of the block-side water jacket 31) is shown. The present invention can be applied to a cooling device in which the block thermo valve 82 is disposed on the coolant outlet side of the cylinder block 3 (downstream end of the block-side water jacket 31). In this case, the cooling water supply path to the hot water cut valve 83 does not pass through the block thermo valve 82, and the passage branched from the cooling water inlet side of the cylinder block 3 or the block inlet passage 11 b of the hot water cut valve 83. It is configured to be connected to the cooling water inlet 83a.

  Moreover, although the example which applied this invention to the cooling device of the engine 1 with which a vehicle is mounted was demonstrated in the said embodiment, it is not restricted to this, Also with respect to the cooling device of internal combustion engines other than a vehicle engine. The present invention is applicable.

  INDUSTRIAL APPLICABILITY The present invention can be used for a cooling device for an internal combustion engine (engine) mounted on a vehicle or the like, and more specifically, cooling provided with a plurality of thermo valves for switching the flow path of cooling water as the engine warms up. It can be used effectively for equipment.

1 engine (internal combustion engine)
1a Engine body (internal combustion engine body)
2 Cylinder head 21 Head side water jacket (cooling water passage of cylinder head)
21b Cooling water outlet 3 Cylinder block 31 Block side water jacket (Cylinder block cooling water passage)
31b Cooling water outlet 4 Water pump 4a Discharge port 6 Radiator 6b Cooling water outlet 7 Throttle body 81 Main thermo valve 81b Cooling water inlet (first cooling water inlet)
81c Cooling water inlet (second cooling water inlet)
81d Cooling water outlet 82 Block thermo valve 82a Cooling water inlet 82b Cooling water outlet (first cooling water outlet)
82c Cooling water outlet (second cooling water outlet)
83 Hot water cut valve 83a Cooling water inlet α Block thermo switching temperature β Hot water cut switching temperature γ Main thermo switching temperature

Claims (3)

A hot water cut valve that supplies cooling water to the cooling water passage of the throttle body when the internal combustion engine is cold, and stops supplying the cooling water to the cooling water passage of the throttle body after the internal combustion engine is warmed up;
A block thermo valve that supplies cooling water to the cooling water passage of the cylinder head when the internal combustion engine is cold, and supplies cooling water to the cooling water passage of the cylinder head and the cooling water passage of the cylinder block after the internal combustion engine is warmed up; ,
A main thermo valve that stops the flow of cooling water between the radiator and the internal combustion engine body when the internal combustion engine is cold, and circulates the cooling water between the radiator and the internal combustion engine body after the internal combustion engine is warmed up; In an internal combustion engine cooling device comprising:
Cooling water temperature at which the block thermo valve shifts from a state of supplying cooling water to the cooling water passage of the cylinder head to a state of supplying cooling water to each of the cooling water passage of the cylinder head and the cooling water passage of the cylinder block More than the block thermo switching temperature, the hot water cut valve shifts from a state of supplying cooling water to the cooling water passage of the throttle body to a state of stopping the supply of cooling water to the cooling water passage of the throttle body. The hot water cut switching temperature that is the cooling water temperature to be set is set high,
The main thermo valve circulates the cooling water between the radiator and the internal combustion engine body from the state where the main thermo valve stops the flow of the cooling water between the radiator and the internal combustion engine body, than the hot water cut switching temperature. A cooling apparatus for an internal combustion engine, characterized in that a main thermo switching temperature, which is a cooling water temperature that shifts to a state, is set higher. The cooling apparatus for an internal combustion engine according to claim 1,
The block thermo valve communicates with a cooling water inlet into which cooling water discharged from a water pump is introduced, a first cooling water outlet communicating with a cooling water passage of the cylinder block, and a cooling water inlet of the hot water cut valve. A second cooling water outlet is provided;
In this block thermo valve, the first cooling water outlet is closed when cooling water is supplied to the cooling water passage of the cylinder head, and cooling water is supplied to each of the cooling water passage of the cylinder head and the cooling water passage of the cylinder block. In the state where the first coolant outlet is opened, the coolant is supplied to the coolant passage of the cylinder head, and the coolant passage of the cylinder head and the coolant passage of the cylinder block, respectively. The cooling apparatus for an internal combustion engine, wherein the cooling water inlet and the second cooling water outlet are in communication with each other in any state of supplying the cooling water. The cooling apparatus for an internal combustion engine according to claim 1 or 2,
The main thermo valve includes a first cooling water inlet that communicates with a cooling water outlet of the radiator that communicates with a cooling water outlet of a cooling water passage of the cylinder head and a cooling water outlet of the cooling water passage of the cylinder block, and the throttle A second cooling water inlet communicating with the cooling water passage of the body, a cooling water outlet communicating with the water pump suction port,
In the main thermo valve, the first cooling water inlet is closed in a state where the flow of the cooling water between the radiator and the internal combustion engine main body is stopped, and the cooling water is supplied between the radiator and the internal combustion engine main body. A cooling apparatus for an internal combustion engine, characterized in that the first cooling water inlet is opened in a state of circulation so that the cooling water outlet of the radiator and the suction port of the water pump are communicated with each other.

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