JP4575934B2 - Exhaust manifold cooling system - Google Patents

Description

  The present invention relates to an exhaust manifold cooling device that can suitably control the flow rate, flow path, and the like of cooling water that cools an exhaust manifold provided on the exhaust side of an internal combustion engine.

  Conventionally, for example, in order to prevent overheating of an engine that is an internal combustion engine such as a vehicle, a cooling device that holds the engine at an appropriate temperature is provided. This cooling device cools the engine that has generated heat by circulating cooling water supplied from a radiator along a water jacket formed in a cylinder block of the engine.

  Further, conventionally, on the exhaust side of the engine, an exhaust manifold for exhausting combustion gas generated in a combustion chamber is connected to the cylinder block, and the exhaust manifold uses cooling water supplied to the water jacket. It is designed to be cooled.

As a prior art document related to this type of water jacket, for example, in Patent Document 1, an engine cooling water passage of a hot water heater is divided into two systems, a water passage passing through the exhaust manifold and a bypass water passage. When the water temperature sensor shows a value lower than the predetermined temperature, the bypass valve arranged in the middle of the bypass water passage is closed and the engine coolant supplied to the hot water heater flows only through the water passage in the exhaust manifold. Thus, a warm-up promoting device for an internal combustion engine is disclosed in which the heating performance of the hot water heater is improved by heating engine cooling water with the heat of high-temperature exhaust gas.
Japanese Patent Application Laid-Open No. 59-68545 (page 1, lower right column, line 13 to page 2, upper left column, line 4, FIG. 1)

  However, in the prior art, the flow rate of the cooling water flowing into the exhaust manifold is controlled to be proportional to the engine speed (rotation speed) by the pump action of the water pump, like the cooling water supplied to the water jacket. Has been. That is, the water pump that circulates the cooling water is configured to be driven by using the rotation of the crankshaft. Therefore, the circulation speed of the cooling water by the water pump increases as the rotational speed of the engine increases. The supply amount of the cooling water increases in proportion to the rotational speed of the engine.

  Therefore, in the prior art, the flow rate of the cooling water flowing into the exhaust manifold is set by the rotational speed (the number of revolutions) of the engine. Therefore, for example, the material temperature of the exhaust manifold made of aluminum is more than necessary and sufficient. There is a problem that the amount of cooling water flows. In other words, depending on the operating condition of the engine, the exhaust manifold may be cooled excessively more than necessary, and the cooling water causes heat to be radiated from the exhaust manifold more than necessary.

  As a result, in an exhaust treatment device (for example, a three-way catalyst) in which the temperature of exhaust gas introduced at the start of the engine greatly affects the purification performance, the temperature rise (rising temperature) becomes slow and the purification performance (oxidation reduction) Capacity) does not work smoothly, and there is a problem that the exhaust emission performance on the downstream side after the exhaust manifold deteriorates.

  Further, in the prior art, in order to control the flow rate of the cooling water flowing into the exhaust manifold, for example, the shape of the water jacket provided in the exhaust manifold is changed, or the discharge performance of the water pump that circulates the cooling water It is conceivable to change (pump performance). However, the ratio of cooling water flowing into the water jacket of the exhaust manifold near the cylinder head with respect to the total amount of cooling water flowing through the entire engine is set individually according to the size of the engine and engine performance. For this reason, it is difficult to control the flow rate of the cooling water flowing into the exhaust manifold in a general (general) manner by changing the shape of the water jacket or the discharge performance.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an exhaust manifold cooling device that can easily control the flow rate of cooling water for cooling the exhaust manifold.

  In order to achieve the above object, the present invention provides a water jacket that covers an outer peripheral surface of the exhaust manifold and is provided inside the exhaust manifold so as to cool the exhaust manifold provided on the exhaust side of the internal combustion engine with cooling water for the engine. And a flow rate control mechanism for controlling the flow rate of the cooling water flowing through each water jacket, and the like.

  In this case, in the present invention, by controlling the flow rate of the cooling water flowing through each of the water jackets provided in each of the two or more cover members by the flow rate control mechanism, for example, the cooling action is performed on the exhaust manifold. In addition to the amount of cooling water flowing, for example, the distribution site, distribution time, distribution timing, and the like can be controlled easily.

  In other words, in the present invention, the exhaust manifold is covered with two or more cover members, each jacket member is provided with a water jacket through which cooling water for the engine flows, and the cooling water flowing through the water jacket is flowed. By controlling each by the control mechanism, a cooling action can be exerted only on a desired portion of the exhaust manifold, and a cooling action or the like can be exerted at a desired timing.

  The flow rate control mechanism is constituted by a flow rate control valve provided for each cover member, and a control means for controlling the valve opening degree of the flow rate control valve is provided, thereby simplifying the structure. Therefore, the control can be easily performed without using a complicated control method.

  It is possible to provide a cooling device for an exhaust manifold that can easily control the flow rate of cooling water for cooling the exhaust manifold.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a schematic configuration diagram of an automobile cooling system to which an exhaust manifold cooling device according to an embodiment of the present invention is applied, and FIG. 2 is a perspective view of an engine including the exhaust manifold cooling device.

  As shown in FIG. 1, this automotive cooling system 10 includes a V-type 6-cylinder engine 20 having a cylinder block 16 and a cylinder head 18 each having a cooling water passage 12 and a cylinder water jacket 14 formed on the outer periphery. The radiator 26 is connected to the first circulation passage 22 and the second circulation passage 24 for cooling the cooling water returned from the engine 20 by the outside air and feeding it to the engine 20 again. A fan 28 for blowing air to the radiator 26 is included below.

  The automobile cooling system 10 includes a pair of exhaust manifolds 30a and 30b (see FIG. 2) connected to the exhaust side of the engine 20, and a plurality of division passages. The pair of exhaust manifolds 30a and 30b includes a pair of exhaust manifolds 30a and 30b. An exhaust manifold cooling device 32 (hereinafter simply referred to as a cooling device 32) that cools each of them using cooling water supplied to the engine 20, a first passage 34a that communicates with the cooling water passage 12 of the cylinder head 18, and a postscript And a heater 36 for heating the cooling water flowing through the second passage 34b communicating with the thermostat 38.

  1, only one part (three cylinders) of a V-type six-cylinder engine 20 in which the cylinders are arranged in a V-shape so as to face each other when viewed from the side is shown, and the other part (three cylinders) is shown. In order to make it easy to understand the flow state of the cooling water, the cylinder water jacket 14 of the cylinder block 16 and the cooling water passage 12 of the cylinder head 18 are shown in a simplified plan view.

  Further, the automobile cooling system 10 is disposed in the first circulation passage 22 between the radiator 26 and the engine 20, and the first circulation between the radiator 26 and the circulating water becomes a predetermined temperature when the circulating cooling water reaches a predetermined temperature. A thermostat 38 that opens the passage 22 and a water pump 40 that circulates cooling water between the radiator 26 and the engine 20 are provided.

  As shown in FIG. 2, on the downstream side of the exhaust manifolds 30a and 30b, which are the exhaust side of the engine 20, a gas temperature sensor 41 for detecting the temperature of the exhaust gas, and harmful substances contained in the exhaust gas ( A three-way catalyst 42 that mainly purifies hydrocarbons HC, carbon monoxide CO, and nitrogen oxides NOx) by oxidation and reduction, and a muffler 44 that exhausts the purified exhaust gas toward the atmosphere, respectively. . A three-way catalyst temperature sensor 46 for detecting a three-way catalyst temperature T2 (described later) is attached to the three-way catalyst 42.

  As shown in FIG. 1, the cooling device 32 includes a first communication path 50 a that branches from a middle of a path 48 that communicates the water pump 40 and the cylinder head 18 and introduces cooling water, and a cooling water path of the cylinder head 18. The first cover member 52a is connected to the second communication passage 50b that leads to the cooling water and is connected to the second communication passage 50b. The first cover member 52a covers the upper surface of each exhaust manifold 30a (30b), and And a second cover member 52b to be covered (see FIG. 3). In this case, the first communication passage 50a for introducing the cooling water may be directly connected to the radiator 26, and the cooling water may be introduced from the radiator 26 into the cooling device 32.

  The first cover member 52a and the second cover member 52b are preferably configured identically from the viewpoint of reducing the number of parts. Further, as shown in FIG. 3, the first cover member 52a and the second cover member 52b have a plurality of tongue pieces having a cross-sectional curve portion corresponding to the circular tube section of the exhaust manifold 30a (30b). However, it extends substantially parallel to the direction orthogonal to the axis of the tubular body portion, and is connected at one end thereof. Note that a slit is formed between the adjacent tongue pieces, which is closed before one end of the tongue piece.

  In addition, the cooling device 32 includes cooling water that flows along water jackets 54 (see notches in FIG. 3) provided in the inner space of the first cover member 52a and the second cover member 52b, respectively. By deriving control signals to the first flow control valve 56a and the second flow control valve 56b that function as a flow control mechanism for controlling the flow, respectively, and to the first flow control valve 56a and the second flow control valve 56b. And an electronic control unit (ECU) 58 that functions as a control means for controlling the valve opening degree of the valve body (separation distance between the seating portion and the valve body) (not shown). The first flow control valve 56a and the second flow control valve 56b may be constituted by, for example, a solenoid valve, a pilot valve that operates with a pilot pressure, or a spool valve. In FIG. 3, the cooling water flowing along the water jacket 54 is shown in a simplified manner with broken lines.

  The first flow control valve 56a and the second flow control valve 56b are constituted by, for example, a well-known butterfly valve or a shutter valve (not shown), and the displacement amount of the valve body with respect to the seating portion (the valve body and the seating portion The separation distance or the tilt angle of the valve body) is provided to be controllable by the ECU 58.

  In the present embodiment, the first flow control valve 56a and the second flow control valve 56b are disposed on the upstream side of the first cover member 52a and the second cover member 52b, respectively. The flow rate of the cooling water flowing into the cover member 52b is configured to be controlled. However, the present invention is not limited to this. For example, the first flow control valve 56a and the second flow control valve 56b are provided. The cooling water circulation amount may be controlled by disposing the first cover member 52a and the second cover member 52b on the downstream side. Further, the first flow control valve 56a and the second flow control valve 56b may be configured so as to be provided integrally with the first cover member 52a and the second cover member 52b, for example. Furthermore, instead of the first flow control valve 56a and the second flow control valve 56b, the flow rate of the cooling water may be controlled using the opening / closing operation of the thermostat 38.

  A heater flow control valve 60 for controlling the flow rate of the cooling water supplied to the heater 36 is provided on the upstream side of the heater 36, and the heater flow control valve 60 is based on a control signal output from the ECU 58. Thus, the valve opening degree of a valve body (not shown) is controlled.

  The first cover member 52a and the second cover member 52b are provided with a pair of first temperature sensors 62a and 62b for detecting the temperature of the cooling water flowing through the water jacket 54 and leading the detection signal to the ECU 58, respectively. It is done. The pair of exhaust manifolds 30a and 30b are provided with a pair of second temperature sensors 64a and 64b for detecting the temperature of each exhaust manifold 30a (30b) itself and deriving the detection signal to the ECU 58.

  The automobile cooling system 10 incorporating the exhaust manifold cooling device 32 according to the embodiment of the present invention is basically configured as described above. Next, the function and effect will be described.

  First, the cooling water fed from the radiator 26 is introduced into the water pump 40 through the first circulation passage 22 and the thermostat 38, and is supplied toward the engine 20 under the rotational driving action of the water pump 40. . On the engine 20 side, after the cooling water flows along the cooling water passage 12 of the cylinder head 18, the cooling water is supplied to the cylinder water jacket 14 of the cylinder block 16. The refrigerant is introduced into the radiator 26 through the second circulation passage 24 on the return side and circulated.

  Thus, in a state where the coolant is circulating between the radiator 26 and the engine 20, for example, the ECU 58 operates the engine 20 based on detection signals from the gas temperature sensor 41 and the second temperature sensors 64a and 64b. When it is determined that the exhaust manifolds 30a and 30b are cooled more than necessary and the temperature of the exhaust manifolds 30a and 30b is lowered depending on the situation, the first flow control valve 56a and / or the second flow control valve 56b A control signal is derived. The specific contents of the temperature control will be described later in detail along the flowcharts shown in FIGS.

  In the first flow control valve 56a and / or the second flow control valve 56b, a valve body (not shown) is displaced from the seating portion based on a control signal from the ECU 58 and set to a desired valve opening. The cooling water whose flow rate is controlled based on the set valve opening is supplied to the water jacket 54 of the first cover member 52a and / or the second cover member 52b and circulates, whereby the exhaust manifold 30a, The cooling effect on 30b is suppressed.

  In this case, under the control action of the ECU 58, the circulation of the cooling water to both the first flow rate control valve 56a and the second flow rate control valve 56b is stopped, or the cooling water is caused to flow only to the first flow rate control valve 56a. And the circulation of the cooling water to the second flow rate control valve 56b is stopped, or the cooling water is made to flow only to the second flow rate control valve 56b and the cooling water to the first flow rate control valve 56a contrary to the above. It is possible to stop the distribution of

By controlling the ECU 58 with respect to the first flow control valve 56a and the second flow control valve 56b,
The cooling action on the entire surface of the exhaust manifold 30a (30b) is stopped, the cooling action is exerted only on the upper surface of the exhaust manifold 30a (30b) by the first cover member 52a, or the exhaust manifold 30a is given by the second cover member 52b. It becomes possible to exert a cooling action only on the lower surface portion of (30b).

  As described above, by the valve switching action of the first flow rate control valve 56a and / or the second flow rate control valve 56b, a part that exerts a cooling action on the exhaust manifolds 30a and 30b can be set as a desired part and desired. The cooling action can be exerted at the timing.

  At that time, the first cover member 52a and the second cover member are adjusted by adjusting the valve opening (valve switching position) of a valve body (not shown) provided in each of the first flow control valve 56a and the second flow control valve 56b. It becomes possible to control the circulation amount of the cooling water to the water jacket 54 provided in each 52b digitally (stepwise) or in an analog manner.

  In the present embodiment, the first flow rate control valve 56a and the second flow rate control valve 56b are set according to the flow amount, flow portion, flow time, flow timing, and the like of the cooling water that exerts a cooling action on the exhaust manifolds 30a, 30b. Can be easily controlled.

  In this embodiment, the ECU 58 is controlled by having a plurality of divided cooling water circulation circuits including a water jacket 54 provided on the first cover member 52a and a water jacket 54 provided on the second cover member 52b. Under the action, the cooling water can be flowed only into the necessary parts, and the necessary minimum cooling action can be exerted on each part of the exhaust manifolds 30a and 30b. As a result, in this embodiment, it is possible to minimize a decrease in the exhaust gas temperature on the downstream side of the exhaust manifolds 30a and 30b, and to improve the exhaust emission performance.

  Furthermore, in this embodiment, the amount of heat received by the cooling water is minimized by controlling the flow rate of the cooling water regardless of the rotational speed of the engine 20 by the first flow rate control valve 56a and the second flow rate control valve 56b. The cooling system elements (for example, the radiator 26, the fan 28, the fan driving motor 27, etc.) can be reduced in size and weight, and the efficiency of a narrow space (free layout) can be achieved. Manufacturing cost can be reduced.

  Furthermore, in the present embodiment, the ECU 58 controls the flow rate of the cooling water that exerts a cooling action on the exhaust manifolds 30a, 30b. The heat damage which generate | occur | produces in the supercharger (not shown) provided in the side, the three way catalyst 42 grade | etc., Can be prevented suitably.

  Furthermore, when the cooling device 32 according to the present embodiment is applied to a diesel engine, the diesel engine has high thermal efficiency, so that the temperature of the cooling water gradually rises so that the warming action of the heater 36 is not quickly exhibited. At this time, as will be described later, it is possible to improve the warming performance of the heater 36 by increasing the flow rate of the cooling water flowing through the heater 36 under the control action of the ECU 58 and increasing the temperature of the cooling water at an early stage. Yes (see FIG. 7). In addition, in this embodiment, although the case where it applies to the cooling system 10 for motor vehicles is shown as the example, it is not limited to a vehicle, For example, it applies with respect to internal combustion engines, such as a ship, a cultivator, and a generator. Of course it can be done.

  Next, an example of a cooling control method for the exhaust manifold 30a will be described below along the flowchart shown in FIG. As a premise, a temperature prediction map (to be described later) in which the reference temperature of the exhaust manifold 30a is set to 250 ° C., for example, is stored in a memory (not shown) of the ECU 58 so that it can be read out appropriately. It is assumed that the valve opening of 56a is provided so as to be controllable in switching of the valve position in six stages from a valve opening 0 that is fully closed to a valve opening 5 that is fully open.

  First, the temperature T1 of the exhaust manifold 30a is detected by the second temperature sensor 64a (step S1), and the temperature detection signal is output to the ECU 58. The ECU 58 determines whether or not the temperature T1 of the exhaust manifold 30a output from the second temperature sensor 64a is higher than 250 ° C., which is a reference temperature set in advance in the temperature prediction map (step S2).

  If the temperature T1 of the exhaust manifold 30a is higher than 250 ° C. (when YES in step S2 → step S3), the ECU 58 then determines whether the current valve opening of the flow control valve 56a is 5 (fully open). Judge whether or not.

  In the step S3, when the current valve opening degree of the flow control valve 56a is 5 (fully open) (when YES in step S3 → step S5), the ECU 58 further detects by the second temperature sensor 64a. Further, it is determined whether or not the temperature T1 of the exhaust manifold 30a is higher than a predetermined temperature set in advance by a temperature prediction map. The predetermined temperature set by the temperature prediction map is higher than the reference temperature of 250 ° C., and is set to, for example, 300 degrees.

  On the other hand, in the step S3, when the current valve opening degree of the flow control valve 56a is not 5 (fully open) and the valve opening degree is 4 or less (NO in step S3 → step S4), The ECU 58 derives a control signal to the flow control valve 56a and switches and controls the valve position so as to increase the valve opening of the valve body by one step (step S4). Increase by a predetermined amount. For example, when the valve opening degree of the flow control valve 56a at that time is 3, by setting the valve opening degree of the valve body to the valve opening degree 4 (3 + 1 = 4) increased by one step, the flow control valve 56a The cooling effect can be enhanced by increasing the amount of cooling water flowing through.

  In the step S5, when the temperature T1 of the exhaust manifold 30a is higher than the predetermined temperature (YES in step S5 → step S6), the ECU 58 derives an energizing signal to the motor 27 to strengthen the fan 28. After the engine is driven to rotate at a high speed for a predetermined time (step S6), the output control of the engine 20 is then performed to reduce the heat generation amount of the exhaust manifold 30a (step S7). The output control of the engine 20 is performed, for example, by deriving a control signal from the ECU 58 to a fuel injection valve (not shown) to suppress the fuel injection amount.

  On the other hand, when the temperature T1 of the exhaust manifold 30a is equal to or lower than the predetermined temperature (when NO in step S5 → step S8), the ECU 58 derives an energizing signal to the motor 27 and causes the fan 28 to run at a low speed for a predetermined time with weak operation After being driven to rotate (step S8), subsequently, a drive switching signal is derived to the motor 27, and switching control is performed to a strong operation for rotating the fan 28 at a high speed for a predetermined time (step S9). The fan 28 is measured for a predetermined time by a timer circuit (not shown), and then a deactivation signal from the ECU 58 is introduced into the motor 27 and is turned off (step S9a).

  In step S2, when the temperature T1 of the exhaust manifold 30a is 250 ° C. or less (NO in step S2 → step S10), the ECU 58 continues to set the opening degree of the flow control valve 56a to 0 ( (Step S10), and when the valve opening is 0, the process is finished as it is, and when the valve opening is not 0, the current valve of the flow control valve 56a is terminated. The valve position is lowered by one step (step S11). For example, when the valve opening degree of the flow rate control valve 56a at that time is 3, the valve opening degree of the valve body is set to a valve opening degree 2 (3-1 = 2) that is lowered by one step.

  The above cooling control method shown in FIG. 4 is applied to each exhaust manifold 30a (30b), and the temperature can be controlled for each exhaust manifold 30a (30b).

  Next, a temperature prediction map in each part of the exhaust manifolds 30a and 30b will be described.

  As shown in FIG. 5, the temperature prediction map includes exhaust gas temperature data detected by a gas temperature sensor 41, fuel injection amount data of a fuel injection valve (not shown), engine load characteristics, and air in an intake manifold (not shown). It is preset based on the intake amount data and the like, and is stored in a memory (not shown) of the ECU 58. The ECU 58 reads out the temperature prediction map as needed, and feedback-controls the amount of cooling water flowing through the water jacket 54 provided in each exhaust manifold 30a (30b).

  Next, FIG. 6 shows a flowchart relating to an example of a cooling control method for protecting the three-way catalyst 42 provided on the downstream side of the exhaust manifold 30a. As a premise, a temperature prediction map in which the reference temperature of the three-way catalyst 42 is set to, for example, 850 ° C. is stored in a memory (not shown) of the ECU 58 so as to be appropriately readable, and the valve of the flow control valve 56a is provided. The opening is divided into six stages from a fully open valve opening 0 to a fully open valve opening 5 in the same manner as described above so that the switching of the valve position can be controlled.

  First, the three-way catalyst temperature sensor 46 detects the three-way catalyst temperature T2 (step S21), and outputs the temperature detection signal to the ECU 58. The ECU 58 determines whether or not the three-way catalyst temperature T2 output from the three-way catalyst temperature sensor 46 is higher than a reference temperature 850 ° C. set in advance in the temperature prediction map (step S22).

  If the three-way catalyst temperature T2 is higher than 850 ° C. (YES in step S22 → step S23), then the ECU 58 determines whether the current valve opening of the flow control valve 56a is 5 (fully open). Determine whether.

  In the step S23, when the current valve opening degree of the flow control valve 56a is 5 (fully open) (when YES in step S23 → step S25), the ECU 58 further detects by the three-way catalyst temperature sensor 46. It is determined whether or not the three-way catalyst temperature T2 is greater than a predetermined temperature set in advance by a temperature prediction map. The predetermined temperature set by the temperature prediction map is larger than the reference temperature 850 ° C., for example, 950 degrees.

  On the other hand, in the step S23, when the current valve opening degree of the flow control valve 56a is not 5 (fully open) and the valve opening degree is 4 or less (NO in step S23 → step S24), The ECU 58 derives a control signal to the flow rate control valve 56a and switches and controls the valve position so as to increase the valve opening of the valve body by one step (step S24). Increase by a predetermined amount. For example, when the valve opening degree of the flow control valve 56a at that time is 3, by setting the valve opening degree of the valve body to the valve opening degree 4 (3 + 1 = 4) increased by one step, the flow control valve 56a The cooling effect can be enhanced by increasing the amount of cooling water flowing through.

  In the step S25, if the three-way catalyst temperature T2 is higher than the predetermined temperature (YES in step S25 → step S26), the ECU 58 derives an urging signal to the motor 27 and causes the fan 28 to operate strongly. Then, the engine 20 is rotated at a high speed for a predetermined time (step S26), and then the output control of the engine 20 is performed to reduce the heat generation amount of the three-way catalyst 42 (step S27). The output control of the engine 20 is performed, for example, by deriving a control signal from the ECU 58 to a fuel injection valve (not shown) to suppress the fuel injection amount.

  On the other hand, when the three-way catalyst temperature T2 is equal to or lower than the predetermined temperature (NO in step S25 → step S28), the ECU 58 derives an energizing signal to the motor 27 and rotates the fan 28 at a low speed for a predetermined time with a weak operation. After driving (step S28), a drive switching signal is derived to the motor 27 and the fan 28 is controlled to switch to strong operation (step S29). The fan 28 is measured for a predetermined time by a timer circuit (not shown), and then a deactivation signal from the ECU 58 is introduced into the motor 27 to be turned off (step S29a).

  Further, in the step S22, when the three-way catalyst temperature T2 is 850 ° C. or lower (NO in step S22 → step S30), the ECU 58 subsequently sets the flow rate control valve 56a to 0 (all (Step S30), and when the valve opening degree is 0 (fully closed), the process is terminated as it is. When the valve opening degree is not 0, the flow control valve 56a is closed. The current valve opening is set to a valve position lowered by one step (step S31). For example, when the valve opening degree of the flow rate control valve at that time is 3, the valve opening degree of the valve body is set to a valve opening degree 2 (3-1 = 2) that is lowered by one step.

  By suitably controlling the three-way catalyst temperature T2 in this way, it is possible to prevent the occurrence of heat damage in the three-way catalyst 42 and a supercharger (turbocharger) (not shown) and protect it appropriately. .

  Next, FIG. 7 shows a flowchart relating to an example of a cooling control method for demonstrating the warming action of the heater 36 at an early stage. As a premise, a temperature prediction map in which the reference temperature range of the cooling water temperature T3 is set to, for example, a range of 85 to 110 ° C. is stored in a memory (not shown) of the ECU 58 and provided in an appropriately readable manner. The valve opening degree of the control valve 56a is divided into six stages from a fully open valve opening degree 0 to a fully open valve opening degree 5 in the same manner as described above in that the switching of the valve position can be controlled. It is.

  First, a heater switch (not shown) is energized by an energization signal output from the ECU 58, and the heater 36 is turned on (step S41). Subsequently, the coolant temperature T3 is detected by the first temperature sensor 62a (step S42), and the detection signal is derived to the ECU 58. The ECU 58 determines whether or not the coolant temperature T3 output from the first temperature sensor 62a is higher than 110 ° C., which is the upper limit of the reference temperature range set in advance in the temperature prediction map (step S43).

  When it is determined that the cooling water temperature T3 is higher than 110 ° C., which is the upper limit of the reference temperature range (YES in step S43 → step S44), the ECU 58 provides an energizing signal to the motor 27 because the cooling water is in an overheated state. Then, the fan 28 is driven to rotate at a high speed for a predetermined time with a strong operation, and then the output control of the engine 20 is performed to reduce the temperature of the cooling water (step S44). The output control of the engine 20 is performed, for example, by deriving a control signal from the ECU 58 to a fuel injection valve (not shown) to suppress the fuel injection amount, and the like.

  On the other hand, when the cooling water temperature T3 is 110 ° C. or lower (NO in step S43 → step S45), the ECU 58 further determines that the cooling water temperature T3 output from the first temperature sensor 62a is the temperature prediction map. It is determined whether or not the temperature is lower than 85 ° C., which is the lower limit of the reference temperature range set to (step S45).

  When the cooling water temperature T3 is lower than 85 ° C. (YES in step S45 → step S46), the ECU 58 sets the flow control valve 56a to the flow control valve 56a so that the valve control valve is fully opened (valve opening 5). Output a control signal. When the valve opening degree of the flow control valve 56a is fully opened, the circulation amount of the cooling water is increased. On the other hand, when the cooling water temperature T3 is not less than 85 ° C. (NO in step S45), the cooling water temperature T3 is 85 ° C. or more and 110 ° C. or less (85 ≦ T3 ≦ 110 ° C.) and coincides with the reference temperature range. Since the temperature is appropriate, the process is terminated.

  In step S46, after fully opening the valve opening of the flow control valve 56a, the ECU 58 determines whether or not the fan 28 is in an on state (step S47), and if the fan 28 is in an on state (step S47). In step S47, YES → step S48), a deactivation signal is output to the motor 27 to turn off the fan 28. On the other hand, if the fan 28 is in the off state (NO in step S47 → step S49), it remains as it is. Continue off.

  After the fan 28 is turned off in step S48, the ECU 58 further determines whether or not the cooling water temperature T3 is 85 ° C. or higher. If the cooling water temperature T3 is 85 ° C. or higher, the ECU 58 ends. To do. On the other hand, when the cooling water temperature T3 is lower than 85 ° C., the fuel injection amount in a fuel injection valve (not shown) is controlled, and the fuel injection timing is controlled to increase the temperature of the exhaust gas, thereby Is raised to the reference temperature range.

  In this way, the temperature of the cooling water temperature T3 can be controlled so that the heater 36 can be raised quickly, and the warming action can be exerted at an early stage, so that it can be suitably used in an environment such as a cold district.

  Next, FIG. 8 shows an exhaust manifold cooling device 32a according to another embodiment of the present invention. The same constituent elements as those of the exhaust manifold cooling device 32 according to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  An exhaust manifold cooling device 32a (hereinafter simply referred to as a cooling device 32a) according to another embodiment is for cooling the exhaust manifold 100 applied to an in-line four-cylinder engine (not shown).

  The cooling device 32a includes a first cover member 102a that cools the upper surface portion of the exhaust manifold 100 made of a long tube body along the axial direction of the tube body, and a side surface intermediate portion of the exhaust manifold 100 that is the tube body. A second cover member 102b that cools along the axial direction of the tube, and a third cover member 102c that cools the lower surface portion of the exhaust manifold 100 along the axial direction of the tubular body.

  On the upstream side of the first to third cover members 102a to 102c, first to third flow rate control valves 56a to 56c for controlling the flow rate of the cooling water flowing through each water jacket 54 are provided. In this way, by controlling the flow rate of the cooling water flowing through the first to third cover members 102a to 102c, which are divided into, for example, the upper, middle, and lower parts of the exhaust manifold 100 made of a long tubular body. For example, each part of the exhaust manifold 100 can be appropriately cooled as necessary in accordance with the operating condition of the engine.

  The first to third cover members 102a to 102c are integrally molded to form a single cover member (not shown), and a plurality of water jackets 54 are arranged inside the single cover member, and each water jacket 54 is arranged. You may comprise so that the flow volume of the circulating cooling water may be controlled.

1 is a schematic block configuration diagram of an automotive cooling system to which an exhaust manifold cooling device according to an embodiment of the present invention is applied. FIG. 2 is a perspective view of an engine including the exhaust manifold cooling device. FIG. 4 is a partially cutaway perspective view of a first cover member that constitutes the exhaust manifold cooling device. It is a flowchart regarding an example of the cooling control method of an exhaust manifold. It is a figure with which it uses for description of the temperature prediction map in each part of an exhaust manifold. It is a flowchart regarding an example of the cooling control method for protecting the three way catalyst provided in the downstream of an exhaust manifold. It is a flowchart regarding an example of the cooling control method for exhibiting the warming-up effect | action of a heater at an early stage. FIG. 6 is a perspective view of an exhaust manifold cooling device according to another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automobile cooling system 20 Engine 30a, 30b Exhaust manifold 52a, 52b Cover member 54 Water jacket 56a, 56b Flow control valve 58 Electronic control unit (ECU)

Claims (3)

An apparatus for cooling an exhaust manifold provided on an exhaust side of an internal combustion engine with engine coolant,
At least two or more cover members that cover an outer peripheral surface of the exhaust manifold and cool a predetermined portion of the exhaust manifold by circulating the cooling water along a water jacket provided inside;
A flow rate control mechanism for controlling the flow rate of cooling water flowing through each water jacket;
A cooling device for an exhaust manifold, comprising: In the exhaust manifold cooling device according to claim 1,
The exhaust manifold cooling device, wherein the flow rate control mechanism includes a flow rate control valve provided in each cover member. In the exhaust manifold cooling device according to claim 2,
A cooling device for an exhaust manifold, comprising a control means for controlling a valve opening degree of the flow control valve.

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