JP2017089587A - Intake system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake system for an internal combustion engine capable of inhibiting fuel that is not evaporated from being moved together with suction air and sucked to the internal combustion engine.SOLUTION: An intake system 100 for an internal combustion engine includes: a water injecting section 6 for injecting water to suction air flowing inside an intake system body 100a; a humidity sensor 71 for detecting humidity of the suction air upstream of a water injecting position E of the water injecting section 6; and an ECU 74 for controlling the injection amount of water injected from the water injecting section 6 on the basis of the humidity of the suction air detected by the humidity sensor 71 before the injection of the water.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intake device for an internal combustion engine.

  2. Description of the Related Art Conventionally, an intake device for an internal combustion engine that includes a water injection unit that injects water into intake air to cool the intake air is known (see, for example, Patent Document 1).

  Patent Document 1 discloses a water injection nozzle that injects water into supply air (intake air), an air-water separator that is provided downstream of the water injection nozzle, and collects unevaporated water out of the injected water. An air intake device for an engine for a vehicle is disclosed that includes a dew condensation sensor that is disposed downstream of the air / water separator and detects the relative humidity of the supply air. This intake device is configured to stop water injection from the water injection nozzle when the relative humidity is 94% or more. Here, in general, in a humidity detection unit such as a dew condensation sensor that detects humidity, a detection delay of at least several seconds or more occurs until accurate humidity is detected.

Japanese Utility Model Publication No. 3-43403

  In the intake device of Patent Document 1, since the dew condensation sensor is disposed downstream of the water injection nozzle, the dew condensation sensor needs to detect the humidity of the supply air having a large variation in humidity after water is injected. . For this reason, the dew condensation sensor may not be able to follow fluctuations in humidity. In this case, there is an inconvenience that the difference between the detected humidity and the actual humidity tends to increase. Therefore, in the intake device of Patent Document 1, when the actual humidity is 94% or higher, the humidity may be detected as a low value of less than 94% than the dew condensation sensor. It is thought that water injection is not stopped. As a result, it is considered that the intake device disclosed in Patent Document 1 has a problem that even if an air / water separator is provided, unevaporated water may move with the supply air and be sucked into the engine.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to prevent unvaporized water from moving together with intake air and being sucked into an internal combustion engine. It is an object to provide a possible internal combustion engine intake system.

  To achieve the above object, an intake device for an internal combustion engine according to one aspect of the present invention includes an upstream intake pipe, a throttle, and an intake manifold communicating in this order, and the intake manifold includes an upstream port, a surge tank, and a downstream port. Are in this order, an intake device main body, a water injection unit for injecting water into the intake air flowing through the intake device main body, and a humidity for detecting the humidity of the intake air upstream of the water injection position of the water injection unit A detection unit; and a control unit that controls the amount of water injected from the water injection unit based on the humidity of the intake air before the water injection detected by the humidity detection unit. “Upstream” and “downstream” mean upstream and downstream in the direction in which the intake air flows.

  In the intake device for an internal combustion engine according to one aspect of the present invention, as described above, a humidity detection unit that detects the humidity of the intake air is provided upstream of the water injection position of the water injection unit, and the controller controls the humidity. Based on the humidity of the intake air before water injection detected by the detection unit, the amount of water injected from the water injection unit is controlled. As a result, the amount of water injection is controlled based on the humidity of the intake air having a small variation in humidity before the water is injected, and therefore, based on the humidity of the intake air having a large variation in humidity after the water is injected. As compared with the case where the water injection amount is controlled, it is possible to suppress the humidity detection unit from following the fluctuation of humidity. As a result, it is possible to suppress an increase in the difference between the detected humidity and the actual humidity, so that the amount of water injection can be controlled in accordance with the actual humidity of the intake air. Therefore, it is possible to suppress the non-evaporated water from being moved together with the intake air and sucked into the internal combustion engine, so that it is possible to suppress the occurrence of problems in the internal combustion engine. In addition, since the intake air can be cooled by the injected water, the amount (density) of the intake air taken into the internal combustion engine due to the expansion of the intake air due to heat is suppressed. Can do.

  In the intake device for an internal combustion engine according to the above aspect, the control unit preferably controls the injection amount of water injected from the water injection unit so that the water amount in the intake air after water injection is equal to or less than the saturated water vapor amount. It is configured as follows. With this configuration, water can be prevented from remaining in the intake air in an unevaporated state, so that it is ensured that unevaporated water moves together with the intake air and is sucked into the internal combustion engine. can do.

  The intake apparatus for an internal combustion engine according to the above aspect preferably further includes a temperature detection unit that detects the temperature of the intake air and a flow rate detection unit that detects the flow rate of the intake air, and the control unit includes a humidity detection unit. In addition to the humidity of the intake air before water injection detected by, the water injection unit injects based on the intake air temperature detected by the temperature detection unit and the intake air flow rate detected by the flow rate detection unit It is comprised so that the injection quantity of water may be controlled. If comprised in this way, a control part can acquire the volume of intake air per unit time and saturated water vapor volume based on the detected temperature and flow volume of intake air, respectively. Thereby, the amount of water that can be injected per unit time can be acquired from the saturated water vapor amount, the volume of the intake air per unit time, and the humidity of the intake air before water injection. As a result, the amount of water injected can be controlled in accordance with the amount of water that can be injected per unit time (the amount of water that can be vaporized), so that non-evaporated water can be combined with the intake air. It is possible to reliably suppress the movement and the suction into the internal combustion engine.

  In this case, it is preferable to further include a pressure detection unit that detects the pressure of the intake air, and the control unit includes the intake air in addition to the humidity of the intake air before water injection, the temperature of the intake air, and the flow rate of the intake air. The amount of water jetted from the water jetting unit is also controlled based on the pressure. If comprised in this way, the quantity of the water which can be injected per unit time can be acquired more correctly based on the detected pressure of the intake air.

  In the intake device for an internal combustion engine according to the above aspect, the water injection position of the water injection unit is preferably located at the upstream port of the intake manifold, and the water injection unit supplies water toward the surge tank of the intake manifold. It is comprised so that it may inject. Here, since the surge tank generally has a larger passage cross-sectional area than the upstream port, the intake air is depressurized by moving from the upstream port into the surge tank, and as a result, is included in the air sucked into the surge tank. The partial pressure of water (water vapor) is also reduced. As a result, the amount of water that can be included in the intake air in the surge tank increases. Focusing on this point, in the present invention, by configuring the water injection unit to inject water toward the surge tank, it is possible to increase the amount of water that can be vaporized and to increase the amount of unevaporated water. It is possible to effectively suppress the remaining water in the intake air.

  Preferably, the intake device for an internal combustion engine according to the above aspect further includes a turbulent flow generation unit that is disposed downstream of the water injection position of the water injection unit and generates a turbulent flow in the intake air flow. If comprised in this way, the non-evaporated water can be efficiently vaporized by the generated turbulent flow.

  In the present application, the following other configurations are also conceivable.

(Additional item 1)
That is, in the configuration in which the water injection unit injects water toward the surge tank, preferably, the water injection position of the water injection unit is located at the upstream port on the center line extending in the longitudinal direction of the surge tank, The injection unit is configured to inject water in the longitudinal direction of the surge tank toward the surge tank.

(Appendix 2)
Further, in the configuration further including a turbulent flow generation unit, the turbulent flow generation unit is preferably provided with a fin provided in the intake manifold and extending in the flow direction of the intake air and having a helically twisted portion. Including.

(Additional Item 3)
In this case, preferably, a plurality of fins are attached to the inner wall surface of the upstream port so as to open a central region inside the upstream port, and the water injection unit is configured to inject water toward the central region. Has been.

(Appendix 4)
In the intake device for an internal combustion engine according to the above aspect, preferably, a plurality of downstream ports are provided so as to branch from the surge tank, and the water injection unit is configured to inject water toward the plurality of downstream ports, respectively. The downstream port water injection portion is included.

  According to the present invention, as described above, it is possible to suppress the non-evaporated water from moving together with the intake air and being sucked into the internal combustion engine.

In 1st and 3rd embodiment of this invention, it is the schematic diagram which showed the engine periphery. In the intake device according to the first embodiment of the present invention, it is an enlarged cross-sectional view showing the upstream port of the intake manifold and the periphery of the surge tank. In the 2nd Embodiment of this invention, it is the schematic diagram which showed the engine periphery. In the intake device according to the third embodiment of the present invention, it is an enlarged cross-sectional view showing the upstream port of the intake manifold and the periphery of the surge tank. In the intake device according to the third embodiment of the present invention, it is a view showing the fin from the upstream port side. In 4th Embodiment of this invention, it is the schematic diagram which showed the engine periphery. FIG. 10 is an enlarged cross-sectional view showing an intake manifold upstream port and the vicinity of a surge tank in an intake device according to a first modification of the third embodiment of the present invention. It is the figure which showed the fin from the upstream port side in the intake device by the 1st modification of 3rd Embodiment of this invention. In the intake device by the 2nd modification of 3rd Embodiment of this invention, it is the expanded sectional view which showed the upstream port of the intake manifold and the surge tank periphery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
With reference to FIG. 1 and FIG. 2, the structure of the intake device 100 for an internal combustion engine according to the first embodiment of the present invention will be described.

<Intake device structure, etc.>
An intake device (hereinafter referred to as an intake device) 100 for an internal combustion engine according to the first embodiment of the present invention is an intake device for a multi-cylinder engine 10 (four-cylinder engine in FIG. 1) for an automobile. The intake device 100 is provided upstream of the engine 10 and is configured to guide intake air (intake air) to each cylinder of the engine 10. Further, an exhaust device 20 through which exhaust air (exhaust gas) from the engine 10 circulates is provided downstream of the engine 10. The exhaust device 20 includes an exhaust manifold 21 and an exhaust pipe 22. The engine 10 is an example of the “internal combustion engine” in the claims.

  In the engine 10, as shown in FIG. 1, the respective cylinders are formed side by side in the X direction, and each engine side intake port (not shown) provided in each cylinder of the engine 10 The cylinders are respectively connected to a plurality of downstream ports 53 described later of the intake device 100. As a result, the intake air flowing through the intake device 100 is supplied to the combustion chamber 10 a provided in each cylinder of the engine 10. The engine 10 is driven and controlled by the ECU 74.

  In the intake device 100, an air duct 1, an air cleaner 2, an air hose 3, a throttle 4, and an intake manifold (hereinafter referred to as intake manifold) 5 are connected so as to communicate with each other in this order. Is formed. An intake passage I through which intake air flows is formed in the intake device main body 100a. The air hose 3 is an example of an “upstream intake pipe” in the claims.

  The air duct 1 is provided for taking outside air into the intake passage I of the intake device main body 100a as intake air. The air cleaner 2 has an air filter 2a, and has a function of removing the foreign matters contained in the intake air sucked into the intake passage I from the air duct 1 and purifying the intake air.

  A throttle valve 4 a is arranged inside the throttle 4. The throttle valve 4a has a function of adjusting (squeezing) the flow rate of the intake air flowing through the intake passage I by the rotation state being controlled by an ECU 74 described later.

  In the intake manifold 5, an upstream port 51, a surge tank 52, and a plurality (four in FIG. 1) of downstream ports 53 are connected to communicate in this order. The upstream port 51 communicates with the throttle 4. Further, since the upstream port 51 is curved, it extends in the longitudinal direction (X direction) of the surge tank 52, and the center line O passing through the center in the plane orthogonal to the X direction intersects the upstream port 51. ing.

  The surge tank 52 has a function of storing intake air and distributing the intake air to each of the plurality of downstream ports 53. The surge tank 52 is formed so as to extend along the X direction in which the cylinders are arranged. The surge tank 52 is formed so as to expand from the upstream port 51. As a result, the intake passage I in the surge tank 52 has a larger passage cross-sectional area than the intake passage I in the upstream port 51. The plurality of downstream ports 53 are provided in the same number as the cylinders of the engine 10 and are branched from the surge tank 52.

  The intake device 100 also includes a water injection unit 6, a humidity sensor 71, a temperature sensor 72, a flow rate sensor 73, and an ECU 74 that also performs drive control of the engine 10. The humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 are examples of the “humidity detection unit”, “temperature detection unit”, and “flow rate detection unit” in the claims, respectively. The ECU 74 is an example of the “control unit” in the claims.

  The water injection unit 6 sucks up the water stored in the water tank 62, the water injection nozzle 61 that injects water toward the intake air in the intake passage I, the water tank 62 that stores the injected water. And a pump (P) 63 for applying a pressure for spraying from the water spray nozzle 61.

  As shown in FIG. 2, the water injection nozzle 61 is attached to the upstream port 51 of the intake manifold 5 at a position that substantially intersects the center line O of the surge tank 52. The water injection nozzle 61 is configured to inject water in the X direction in which the center line O extends toward the surge tank 52 of the intake manifold 5 from a position substantially intersecting with the center line O (water injection position E). . Note that “injecting water in the X direction” means not only injecting water in the X direction so as not to spread from the center line O, but also injecting water in the X direction so as to spread around the center line O. It is a broad concept that includes cases.

  Thereby, when the injected water is vaporized, the heat of the intake air is taken away as the heat of vaporization, whereby the intake air after the water injection is cooled and the temperature of the intake air is lowered. Thereby, since the amount (density) of air contained in the intake air can be increased, the amount of air sent into the combustion chamber 10a of the engine 10 can be increased, and as a result, the output of the engine 10 is improved. . Furthermore, the occurrence of knocking in the engine 10 can be suppressed by reducing the temperature of the intake air, so that the ignition timing of the engine 10 can be optimized. Thereby, since the thermal efficiency of the engine 10 improves, the fuel consumption of the engine 10 improves.

  Further, since the intake passage I in the surge tank 52 has a larger passage cross-sectional area than the intake passage I in the upstream port 51, the intake air flowing through the upstream port 51 is decompressed in the surge tank 52. As a result, the amount of water (amount of gaseous water) that can be contained in the intake air in the surge tank 52 is increased, so that unevaporated water is suppressed from remaining in the intake air. Further, in the surge tank 52, the flow of the intake air is disturbed by the air flow generated in the step portion 52a provided at the connection portion with the upstream port 51, and a turbulent flow is generated. Thereby, vaporization of non-evaporated water is further promoted by stirring the intake air.

  In addition, the water injection nozzle 61 may be comprised from one nozzle, and may be comprised from the several nozzle arrange | positioned on the concentric circle centering on the centerline O. FIG.

  In the pump 63, the drive is controlled by the ECU 74 to adjust the amount of water injected per unit time supplied to the water injection nozzle 61, the pressure of water to be injected (water pressure), and the like.

  Further, as shown in FIG. 1, the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 are all disposed in the air hose 3 downstream of the air cleaner 2 and upstream of the throttle 4. That is, the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 are all arranged upstream of the water injection position E of the water injection nozzle 61. The humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 have a function of detecting the humidity, temperature, and flow rate of the intake air before flowing through the intake passage I before the water injection. The humidity sensor 71 may detect relative humidity or absolute humidity.

  Further, the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 are disposed at positions where clean intake air that has passed through the air cleaner 2 flows. Thus, it is possible to accurately detect the humidity, temperature, and flow rate of the intake air using the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73. Furthermore, since damage due to foreign matter can be suppressed, the life of the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 can be extended.

(Control of water injection)
Here, in the first embodiment, the ECU 74 controls the water injection unit 6 based on the humidity, temperature, and flow rate of the intake air before water injection detected by the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73, respectively. The amount of water sprayed from the water spray nozzle 61 is controlled. At this time, the humidity of the intake air before water injection detected by the humidity sensor 71 varies depending on weather conditions and the temperature of an engine room (not shown) in which the engine 10 and the intake device 100 are housed, but may be contained in the intake air. The possible amount of water itself is almost unchanged. For this reason, the humidity of the intake air before water injection has less fluctuation in humidity than the humidity of the intake air after water injection in which the amount of water contained in the intake air changes greatly. As a result, the humidity of the intake air can be acquired more accurately by the humidity sensor 71.

  The ECU 74 is configured to acquire the saturated water vapor amount of the intake air after water injection from the temperature of the intake air before water injection detected by the temperature sensor 72. Specifically, the storage unit (not shown) of the ECU 74 stores a temperature map related to the temperature drop degree of the intake air corresponding to the amount of water injected by the water injection unit 6 per unit time. The ECU 74 is configured to estimate the temperature of the intake air after water injection from the temperature decrease degree corresponding to the current water injection amount acquired based on the temperature map and the temperature detected by the temperature sensor 72. ing. Thereby, the ECU 74 is configured to acquire the saturated water vapor amount of the intake air after water injection based on the estimated temperature of the intake air after water injection and the saturated water vapor amount curve stored in the storage unit. . The ECU 74 may calculate an estimated value of the intake air temperature after water injection from the intake air temperature detected by the temperature sensor 72 without using the temperature map. The ECU 74 is configured to acquire the volume of intake air per unit time from the flow rate of intake air detected by the flow sensor 73.

  Then, the ECU 74 can inject from the water injection unit 6 per unit time based on the acquired saturated water vapor amount of the intake air after the water injection, the intake air volume per unit time, and the intake air humidity before the water injection. It is configured to obtain a possible amount of water injection. Specifically, the ECU 74 acquires the amount of water that can be injected per unit volume from the saturated water vapor amount of the intake air after water injection and the humidity of the intake air before water injection. At this time, when the humidity of the intake air before water injection is relative humidity (RH%), the amount of water that can be injected per unit volume is (saturated water vapor amount × (1−relative humidity / 100)), and when the humidity of the intake air before water injection is absolute humidity, the amount of water that can be injected per unit volume is acquired as (saturated water vapor amount−absolute humidity). The Then, the ECU 74 multiplies the amount of water that can be injected per unit volume by the volume of intake air per unit time, thereby allowing water that can be injected from the water injection unit 6 per unit time. The injection amount (injection allowable amount) is acquired.

  And ECU74 is comprised so that the pump 63 of the water injection part 6 may be driven so that the injection amount of water below the injection allowable amount may be injected per unit time based on the acquired injection allowable amount. For example, the ECU 74 drives the pump 63 of the water injection unit 6 so that about 1/5 of the allowable injection amount is injected per unit time. As a result, the ECU 74 controls the amount of water injected from the water injection unit 6 so that the amount of water in the intake air after water injection is less than (less than) the saturated water vapor amount.

(Effect of 1st Embodiment)
In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, the humidity sensor 71 that detects the humidity of the intake air (intake) is provided upstream of the water injection position E of the water injection unit 6, and the humidity sensor 71 detects the humidity by the ECU 74. Based on the humidity of the intake air before water injection, the amount of water injected from the water injection unit 6 is controlled. As a result, the amount of water injection is controlled based on the humidity of the intake air having a small fluctuation in humidity before the water is injected, so that the water is controlled based on the humidity of the intake air having a large fluctuation in humidity after the water is injected. It is possible to suppress the humidity sensor 71 from being able to follow the humidity fluctuation as compared with the case where the injection amount is controlled. As a result, an increase in the difference between the detected humidity and the actual humidity can be suppressed, so that the water injection amount can be controlled in accordance with the actual humidity of the intake air. Therefore, it is possible to suppress the non-evaporated water from being moved together with the intake air and sucked into the engine 10, so that a phenomenon such as a water hammer can be suppressed from occurring in the engine 10. As a result, it is possible to suppress the occurrence of problems in the engine 10.

  Further, in the first embodiment, as described above, the intake air can be cooled by the injected water, so that the amount (density) of intake air taken into the engine 10 due to the expansion of the intake air due to heat. Can be reduced.

  In the first embodiment, as described above, the ECU 74 controls the amount of water injected from the water injection unit 6 so that the amount of water in the intake air after water injection is less than (less than) the saturated water vapor amount. . Accordingly, it is possible to suppress the water from remaining in the intake air in an unevaporated state, and thus it is possible to reliably suppress the non-evaporated water from being moved together with the intake air and sucked into the engine 10.

  In the first embodiment, as described above, in addition to the humidity of the intake air before water injection detected by the humidity sensor 71, the ECU 74 detects the temperature and flow rate of the intake air before water injection detected by the temperature sensor 72. Based on the flow rate of the intake air before the water injection detected by the sensor 73, the injection amount of water injected from the water injection unit 6 is controlled. Thus, the ECU 74 can acquire the saturated water vapor amount and the intake air volume per unit time, respectively, based on the detected intake air temperature and flow rate. As a result, the amount of water that can be injected per unit time can be acquired from the saturated water vapor amount, the volume of intake air per unit time, and the humidity of the intake air before water injection. Therefore, since the amount of water injection can be controlled in accordance with the amount of water that can be injected per unit time (the amount of water that can be vaporized), un-evaporated water moves with the intake air. Thus, it is possible to reliably suppress the suction into the engine 10.

  In the first embodiment, as described above, the water injection position E of the water injection unit 6 is positioned at the upstream port 51 of the intake manifold 5, and the water injection unit 6 is directed toward the surge tank 52 of the intake manifold 5. Configure to spray water. Thereby, while being able to increase the injection quantity of the water which can be vaporized, it can suppress effectively that non-evaporated water remains in intake air.

  In the first embodiment, as described above, the water injection position E of the water injection unit 6 is positioned at the upstream port 51 on the center line O extending in the longitudinal direction of the surge tank 52, and the water injection unit 6 is The water is jetted in the longitudinal direction (X direction) of the surge tank 52 toward the surge tank 52. Thereby, since water can be injected to the position farthest from the inner wall surface of the surge tank 52, it is possible to effectively suppress adhesion of non-evaporated water to the inner wall surface of the surge tank 52. As a result, it is possible to reliably suppress the non-evaporated water from being moved together with the intake air and sucked into the engine 10.

[Second Embodiment]
A second embodiment will be described with reference to FIG. In the second embodiment, an example in which a supercharger 130 is added to the configuration of the first embodiment will be described. In the drawing, the same reference numerals as those in the first embodiment are assigned to the same components as those in the first embodiment, and the description thereof is omitted.

  In the configuration of the second embodiment of the present invention, a supercharger 130 is provided in addition to the engine 10, the intake device 200, and the exhaust device 120. The air hose 103 of the intake device main body 200a is divided into a first air hose 103a and a second air hose 103b. The air hose 103 is an example of the “upstream intake pipe” in the claims.

  The supercharger 130 includes an intake air circulation part 131 disposed between the first air hose 103a and the second air hose 103b, and an exhaust air circulation part 132 disposed between the exhaust manifold 121 and the exhaust pipe 122 of the exhaust device 120. Including. In the exhaust gas circulation part 132, an exhaust turbine (not shown) is rotated by the exhaust gas flowing through the inside. Then, in the intake air circulation part 131, the intake air from the first air hose 103a is compressed and sent out to the second air hose 103b by an intake turbine (not shown) that is rotated by the rotation of the exhaust turbine. Thereby, in the intake passage I downstream of the intake circulation portion 131, the intake pressure and temperature are increased compared to the intake passage I upstream of the intake circulation portion 131.

  In the second embodiment, the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 are all disposed in the second air hose 103 b downstream of the air cleaner 2 and upstream of the throttle 4. More precisely, the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 are all disposed in the second air hose 103 b downstream of the intake air circulation portion 131 of the supercharger 130 and upstream of the throttle 4. Yes. That is, the humidity sensor 71, the temperature sensor 72, and the flow sensor 73 are all disposed upstream of the water injection position E of the water injection unit 6. Furthermore, a pressure sensor 175 for detecting the pressure of intake air after water injection is disposed in the surge tank 52 of the intake manifold 5. The pressure sensor 175 is an example of the “pressure detection unit” in the claims.

  In the second embodiment, the ECU 174 is detected by the pressure sensor 175 in addition to the humidity, temperature, and flow rate of the intake air before water injection detected by the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73, respectively. The amount of water injected from the water injection nozzle 61 of the water injection unit 6 is controlled based on the pressure of the intake air after the water injection. Here, in the second embodiment, due to the intake air being compressed by the supercharger 130, the amount of water that can be contained in the intake air is not compressed (in the vicinity of atmospheric pressure or negative pressure). Less than in the case of inhalation). For this reason, by taking into account the pressure of the intake air after water injection detected by the pressure sensor 175, the ECU 174 obtains a larger amount of water that can be injected per unit time than actual. It can be effectively suppressed. As a result, it is possible to more accurately determine the amount of water that can be injected per unit time. The ECU 174 is an example of the “control unit” in the claims.

  In addition, the other structure of the intake device 200 by 2nd Embodiment is the same as that of the said 1st Embodiment.

(Effect of 2nd Embodiment)
In the second embodiment, the following effects can be obtained.

  In the second embodiment, as described above, the humidity sensor 71 that detects the humidity of the intake air (intake) is provided upstream of the water injection position E of the water injection unit 6, and the humidity sensor 71 detects the humidity by the ECU 174. Based on the humidity of the intake air before water injection, the amount of water injected from the water injection unit 6 is controlled. Thereby, similarly to the said 1st Embodiment, it can suppress that non-evaporated water moves with intake air and is inhaled by the engine 10. FIG.

  In the second embodiment, as described above, the ECU 174 controls the pressure in addition to the humidity, temperature, and flow rate of the intake air before water injection detected by the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73, respectively. Based on the pressure of the intake air after the water injection detected by the sensor 175, the amount of water injected from the water injection nozzle 61 of the water injection unit 6 is controlled. Thereby, the amount of water that can be injected per unit time can be obtained more accurately based on the detected pressure of the intake air. The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

[Third Embodiment]
A third embodiment will be described with reference to FIGS. 1, 4, and 5. In the third embodiment, an example in which fins 255 that generate turbulent flow in the intake air are provided in addition to the configuration of the first embodiment will be described. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted. The fin 255 is an example of the “turbulent flow generation part” in the claims.

  In the intake device 300 according to the third embodiment of the present invention, as shown in FIG. 1, fin members 254 (see FIG. 4) are arranged inside the intake manifold 205 of the intake device main body 300a. As shown in FIG. 4, the fin member 254 is disposed downstream of the water injection position E of the water injection unit 6 in the upstream port 251 of the intake manifold 205. Specifically, the fin member 254 is disposed on the upstream port 251 side (X1 side) near the boundary between the upstream port 251 and the surge tank 52.

  As shown in FIG. 5, the fin member 254 includes a plurality of (four) fins 255 and a cylindrical portion 254 a provided on the X1 side of the fins 255. The cylindrical portion 254a is fitted into a circumferential groove portion 251a provided on the inner wall surface of the upstream port 251. Thereby, the fin member 254 is fixed inside the upstream port 251 of the intake manifold 205.

  As shown in FIG. 4, the plurality of fins 255 are attached to the inner wall surface of the upstream port 251 via a cylindrical portion 254 a at substantially equal angular intervals, and are formed to extend in the direction of intake air flow. ing. Each of the plurality of fins 255 has a spiral portion 255a that is helically twisted. The spiral portion 255a is formed so as to extend while turning toward the downstream side (surge tank 52 side, X2 side) around an axis extending in the X direction.

  Further, as shown in FIG. 5, the plurality of fins 255 are attached to the inner wall surface of the upstream port 251 so as to leave a central region C inside the upstream port 251. The center region C is a region around the center line O at the position in the X direction where the fins 255 are provided. As a result, as shown in FIG. 4, a swirl flow (turbulent flow) swirling toward the downstream side about the center line O extending in the X direction is generated in the intake air by the plurality of fins 255.

  Here, in the third embodiment, the water injection nozzle 61 attached at a position substantially intersecting with the center line O of the surge tank 52 has water in the X direction in which the center line O extends from the water injection position E toward the center region C. Is configured to inject fuel. Thereby, vaporization of the water injected from the water injection unit 6 is further promoted by the swirling flow. In addition, the other structure of the intake device 300 by 3rd Embodiment is the same as that of the said 1st Embodiment.

(Effect of the third embodiment)
In the third embodiment, the following effects can be obtained.

  In the third embodiment, as described above, in the intake device 300, the plurality of fins 255 that generate turbulent flow in the intake air flow are provided downstream of the water injection position E of the water injection unit 6. Thereby, the non-evaporated water can be efficiently vaporized by the generated turbulent flow.

  Further, in the third embodiment, as described above, the plurality of fins 255 provided in the intake manifold 205 are formed with spiral portions 255a that extend in the intake flow direction (X direction) and are spirally twisted. To do. Thereby, since the swirling flow swirling toward the downstream side can be generated in the intake air, vaporization of the injected water can be promoted.

  In the third embodiment, as described above, the plurality of fins 255 are attached to the inner wall surface of the upstream port 251 so as to open the central region C inside the upstream port 251 and the water injection unit 6 is installed in the central region. The water is jetted toward C. As a result, a swirl flow swirling toward the downstream side about the center line O extending in the X direction can be generated in the intake air, so that the sprayed water is prevented from adhering to the fins 255 in an unvaporized state. However, vaporization of the injected water can be promoted. The remaining effects of the third embodiment are similar to those of the aforementioned first embodiment.

[Fourth Embodiment]
A fourth embodiment will be described with reference to FIG. In the fourth embodiment, an example in which a downstream port water injection nozzle 364 for injecting water toward the downstream port 53 is provided in addition to the configuration of the first embodiment. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted. The downstream port water injection nozzle 364 is an example of the “downstream port water injection unit” in the claims.

  In the intake device 400 for an internal combustion engine according to the fourth embodiment of the present invention, as shown in FIG. 6, the water injection unit 306 of the intake device main body 400a further includes a plurality (four) of water injection nozzles 364 for downstream ports. ing. The plurality of downstream port water injection nozzles 364 are attached to the surge tank 352 of the intake manifold 305. The plurality of downstream port water injection nozzles 364 are disposed so as to correspond to each of the plurality of downstream ports 53 branched from the surge tank 352.

  These downstream port water injection nozzles 364 are configured to inject water toward the center of the corresponding downstream port 53 and in the Y direction in which the downstream port 53 extends. That is, the downstream port water injection nozzle 364 is configured to inject water from the water injection position E1 downstream of the humidity sensor 71, the temperature sensor 72, and the flow rate sensor 73 toward the corresponding downstream port 53. . The ECU 374 then determines the water injection nozzle 61 of the water injection unit 306 and the plurality of water injection nozzles 306 based on the humidity, temperature, and flow rate of the intake air before water injection detected by the humidity sensor 71, the temperature sensor 72, and the flow sensor 73, respectively. It is configured to control the amount of water jetted from the downstream port water jet nozzle 364, respectively.

  Here, it is necessary to reduce the nozzle hole diameter of the water injection nozzle 61 in order to make the water to be sprayed fine and easy to vaporize. At this time, the amount of water jetted from the water jet nozzle 61 decreases due to the nozzle hole diameter being reduced. Therefore, in the intake device 400 of the fourth embodiment, in order to cool the intake air even when the nozzle hole diameter is reduced by providing a plurality of downstream port water injection nozzles 364 in addition to the water injection nozzle 61. It is possible to sufficiently cool the intake air by securing a sufficient amount of water to be injected into the tank. In addition, the other structure of the intake device 400 by 4th Embodiment is the same as that of the said 1st Embodiment.

(Effect of 4th Embodiment)
In the fourth embodiment, the following effects can be obtained.

  In the fourth embodiment, as described above, the humidity sensor 71 that detects the humidity of the intake air (intake air) is provided upstream of the water injection positions E and E1 of the water injection unit 306, and the humidity sensor 71 is controlled by the ECU 374. Based on the detected humidity of the intake air before water injection, the amount of water injected from each of the water injection nozzle 61 of the water injection unit 306 and the plurality of downstream port water injection nozzles 364 is controlled. Thereby, similarly to the said 1st Embodiment, it can suppress that non-evaporated water moves with intake air and is inhaled by the engine 10. FIG.

  In the fourth embodiment, as described above, the water injection unit 306 includes a plurality of downstream port water injection nozzles 364 that inject water toward the plurality of downstream ports 53, respectively. As a result, the intake air flowing through each of the downstream ports 53 can be reliably cooled by the water injected from the downstream port water injection nozzle 364, so that the intake air expands due to heat and is taken into the engine 10. It is possible to reliably suppress a reduction in the amount (density) of intake air that is discharged. The remaining effects of the fourth embodiment are similar to those of the aforementioned first embodiment.

[Modification]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims for patent, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to fourth embodiments, the example in which the intake device for an internal combustion engine of the present invention is applied to a multi-cylinder engine for an automobile has been shown, but the present invention is not limited to this. The intake device for an internal combustion engine of the present invention may be applied to an engine other than an automobile engine, or may be applied to a single cylinder type engine.

  In the first, second, and fourth embodiments, the temperature sensor (temperature detection unit) and the flow rate sensor (flow rate detection unit) are disposed upstream of the water injection position. Not limited to. In this invention, you may arrange | position a temperature detection part and a flow volume detection part downstream from a water injection position. Further, while the humidity detector is provided in the intake device of the internal combustion engine, the temperature detector and the flow rate detector may not be provided. For example, the estimated values of the temperature and the flow rate with respect to the driving situation of the internal combustion engine are stored in advance in a storage unit or the like, and the humidity of the intake air detected upstream from the water injection position and the estimated values of the temperature and flow rate of the intake air Based on the above, the intake device of the internal combustion engine may be configured such that the control unit controls the amount of water injected from the water injection unit.

  Moreover, although the example which has arrange | positioned the pressure sensor (pressure detection part) downstream from the water injection position was shown in the said 2nd Embodiment, this invention is not limited to this. In this invention, you may arrange | position a pressure detection part upstream from the water injection position of a water injection nozzle. Furthermore, in the configuration in which the supercharger of the second embodiment is provided, the pressure detection unit may not be arranged. At that time, since the pressure and temperature of the intake air are increased by the supercharger, it is possible to inject the water injection amount per unit time in advance so that the water amount in the intake air is equal to or less than the saturated water vapor amount. It is preferable to set it sufficiently smaller than the amount of fresh water. Furthermore, the pressure detection unit may be arranged in the intake device for the internal combustion engine in which the supercharger of the first and fourth embodiments is not provided.

  Moreover, in the said 3rd Embodiment, although the example which used the fin which has a spiral part was shown as a turbulent flow generation part of this invention, this invention is not limited to this. For example, a plurality of (four) ribs 456 may be provided on the intake manifold 405 as in the first modification of the third embodiment shown in FIGS. 7 and 8. The rib 456 is an example of the “turbulent flow generation part” in the claims.

  As shown in FIG. 7, these ribs 456 are formed so as to straddle the upstream port 451 and the surge tank 452 of the intake manifold 405. Further, the rib 456 is integrally provided on the inner wall surface of the intake manifold 405 so as to extend in the X direction. Further, as shown in FIG. 8, the plurality of ribs 456 are respectively provided on the inner wall surface of the intake manifold 405 at substantially equal angular intervals. In addition, the plurality of ribs 456 are provided so as to open the center region C1 inside the intake manifold 405. Thereby, the rib 456 can generate turbulent flow in the intake air flow.

  Moreover, you may provide the level | step-difference part 556 of multiple (3 steps | paragraphs) in the intake manifold 505 like the 2nd modification of 3rd Embodiment shown in FIG. The step portion 556 is an example of the “turbulent flow generation portion” in the claims. These step portions 556 are provided at the boundary between the upstream port 551 and the surge tank 552. The plurality of stepped portions 556 are provided on the inner wall surface of the intake manifold 505 in a circumferential shape. Thereby, turbulent flow can be generated in the intake air flow by the plurality of stepped portions 556.

  Moreover, although the example which provides a water injection position in both an upstream port and a surge tank was shown in the said 4th Embodiment, this invention is not limited to this. In the present invention, the water injection position may be provided only in the surge tank without being provided in the upstream port.

  In the first, second, and fourth embodiments, the water injection position is provided in the upstream port of the intake manifold, and the humidity sensor (humidity detection unit) is provided in the air hose (upstream intake pipe) upstream of the intake manifold. Although shown, the present invention is not limited to this. In this invention, if the humidity detection part is arrange | positioned upstream from a water injection position, the position which arrange | positions a water injection position and a humidity detection part will not be specifically limited. For example, you may provide both a water injection position and a humidity detection part in the upstream port of an intake manifold.

  Moreover, in the said 1st, 2nd and 4th embodiment, although the example which controls the injection quantity of the water injected from a water injection part by ECU (control part) which performs drive control of an engine (internal combustion engine) was shown, The present invention is not limited to this. In this invention, you may provide the control part which controls the injection quantity of the water injected from a water injection part separately from ECU which controls an internal combustion engine.

  In the configurations of the first, second, and fourth embodiments, an intercooler may be provided in the intake device main body in order to further promote cooling of the intake air. As a result, the intake air can be further cooled. In particular, in the configuration of the second embodiment in which the temperature of the intake air rises due to supercharging, it is preferable to provide an intercooler in the intake device body.

3, 103 Air hose (upstream intake pipe)
4 Throttle 5, 205, 305, 405, 505 Intake manifold 6,306 Water injection unit 10 Engine (internal combustion engine)
51, 251, 451, 551 Upstream port 52, 352, 452, 552 Surge tank 53 Downstream port 71 Humidity sensor (humidity detection unit)
72 Temperature sensor (temperature detector)
73 Flow sensor (Flow detector)
74, 174, 374 ECU (control unit)
100, 200, 300, 400 Intake device for internal combustion engine 100a, 200a, 300a, 400a Intake device body 175 Pressure sensor (pressure detection unit)
255 Fin (turbulent flow generation part)
364 Water injection nozzle for downstream port (water injection unit for downstream port)
456 rib (turbulent flow generation part)
556 Stepped part (turbulent flow generation part)
C, C1 Center area E Water injection position O Center line

Claims (6)

An upstream intake pipe, a throttle, and an intake manifold communicate with each other in this order, and in the intake manifold, an intake device body in which an upstream port, a surge tank, and a downstream port communicate with each other in this order;
A water injection unit for injecting water into the intake air flowing through the inside of the main body of the intake device;
A humidity detector that detects the humidity of the intake air upstream of the water injection position of the water injection unit;
An air intake apparatus for an internal combustion engine, comprising: a control unit that controls an injection amount of water injected from the water injection unit based on humidity of intake air before water injection detected by the humidity detection unit.   The said control part is comprised so that the injection quantity of the water injected from the said water injection part may be controlled so that the water | moisture content in the intake air after water injection may be below a saturated water vapor amount. An intake device for an internal combustion engine. A temperature detector for detecting the temperature of the intake air;
A flow rate detection unit for detecting the flow rate of the intake air,
In addition to the humidity of the intake air before water injection detected by the humidity detection unit, the control unit detects the temperature of the intake air detected by the temperature detection unit and the flow rate of the intake air detected by the flow rate detection unit. 3. The intake device for an internal combustion engine according to claim 1, wherein the intake device is configured to control an injection amount of water injected from the water injection unit on the basis of the above. A pressure detector for detecting the pressure of the intake air;
The control unit controls the injection amount of water to be injected from the water injection unit based on the pressure of the intake air in addition to the humidity of the intake air before the water injection, the temperature of the intake air, and the flow rate of the intake air. The intake device for an internal combustion engine according to claim 3, wherein the intake device is configured to be controlled. The water injection position of the water injection unit is located at the upstream port of the intake manifold,
The intake device for an internal combustion engine according to any one of claims 1 to 4, wherein the water injection unit is configured to inject water toward the surge tank of the intake manifold.   The intake of the internal combustion engine according to any one of claims 1 to 5, further comprising a turbulent flow generation unit that is disposed downstream of a water injection position of the water injection unit and generates a turbulent flow in the flow of intake air. apparatus.

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