JP4735522B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that cools intake air by supplying a cooling medium to an intake path of the internal combustion engine.

  In an internal combustion engine (engine), intake air may be cooled. This is because the occurrence of knocking is suppressed or the volumetric efficiency of the intake air is improved by lowering the intake air temperature. As a means for cooling the intake air, a cooling medium (for example, water) may be supplied to the intake passage of the engine.

  In this case, if the supplied cooling medium does not evaporate sufficiently, the amount of heat taken from the intake air is reduced by that amount, so that the effect of cooling the intake air may not be sufficiently obtained. In addition, it is not desirable that the supplied cooling medium does not evaporate and remains in the intake passage. When the temperature is low, the remaining cooling medium may freeze.

JP-A-9-317480 Japanese Patent Laid-Open No. 61-152594 Japanese Patent No. 2557244 Japanese Utility Model Publication No. 61-97534 JP-A-61-49128

  It is desired that evaporation of the cooling medium is promoted when the cooling medium is supplied to the intake path of the internal combustion engine to cool the intake air.

  An object of the present invention is to provide a control device for an internal combustion engine capable of promoting evaporation of the cooling medium when the cooling medium is supplied to the intake path of the internal combustion engine and the intake air is cooled.

An internal combustion engine control apparatus according to the present invention includes: an injection device that injects a cooling medium for cooling the intake air pressurized by the supercharger downstream of the installation position of the supercharger in the intake path of the internal combustion engine; Cooling period determination means for determining a period during which the pressurized intake air is to be cooled. The period during which the pressurized intake air is to be cooled includes a first period during which the cooling medium is injected, and a second period in which the cooling medium following the first period is not injected, the third viewing including the period in which the second of the cooling medium following the period is ejected, the period in which the cooling medium is injected, The time is set from the start of the injection of the cooling medium until the pressure of the injected cooling medium reaches a predetermined pressure .

  In the control device for an internal combustion engine of the present invention, the period during which the cooling medium is not injected is set to a period during which the cooling medium is not injected with respect to a set value of the cooling medium injection amount during the period during which the cooling medium is injected. In this case, it is set based on the amount of decrease in temperature of the pressurized intake air.

  In the control device for an internal combustion engine according to the present invention, the injection amount of the cooling medium per unit time includes a period during which the cooling medium is injected, an injection amount of the cooling medium during the period during which the cooling medium is injected, and the cooling The period of time during which the cooling medium is not injected when the target value of the amount of decrease in the pressurized intake air temperature is set based on the period during which the medium is not injected. It is set based on the injection amount per unit time of the cooling medium capable of realizing the target value of the amount.

  In the control device for an internal combustion engine according to the present invention, the period during which the cooling medium is not injected is set to a time until the injected cooling medium evaporates.

  In the control apparatus for an internal combustion engine according to the present invention, the cooling period determination means includes an outside air temperature detection means for detecting the temperature of the outside air, and the temperature of the outside air detected by the outside air temperature detection means is predetermined. If the temperature of the pressurized intake air is lower than the outside air temperature, the pressure of the pressurized intake air is higher than the temperature of the pressurized intake air at the start of the period for cooling the pressurized intake air. It is characterized by determining the end of the period during which the pressurized intake air is to be cooled.

  In the control apparatus for an internal combustion engine according to the present invention, the cooling period determination means may be configured to reduce the pressurized intake air when the temperature of the outside air detected by the outside air temperature detection means is equal to or lower than the predetermined outside air temperature. A period for cooling the pressurized intake air is determined based on pressure.

  In the control device for an internal combustion engine of the present invention, an intake air cooling device for cooling the pressurized intake air is provided on the downstream side of the injection position of the cooling medium by the injection device in the intake passage, The outside air temperature detecting means is provided in the vicinity of the intake air cooling device.

  According to the control device for an internal combustion engine of the present invention, when the cooling medium is supplied to the intake path of the internal combustion engine and the intake air is cooled, evaporation of the cooling medium is promoted.

  Hereinafter, an embodiment of a control device for an internal combustion engine of the present invention will be described in detail with reference to the drawings.

(First embodiment)
The first embodiment will be described with reference to FIGS. 1 to 7. The present embodiment relates to a control device for an internal combustion engine that cools intake air by supplying a cooling medium to an intake path of the internal combustion engine.

  In the present embodiment, when the temperature of the intake air is high, the cooling medium (water) is injected into the intake passage by the injection device (water injector). Water is sprayed intermittently. As a result, in the intake path, a layer of high-temperature intake air is sandwiched between the spray of sprayed water (hereinafter referred to as water spray) and the next water spray, so that the mixture of water spray and high-temperature intake air is mixed. Is promoted. For this reason, since evaporation of the injected water is promoted compared to the case where water is continuously injected, the effect of cooling the intake air due to the latent heat of vaporization of water is enhanced.

  FIG. 1 is a schematic configuration diagram of an apparatus according to the present embodiment. In FIG. 1, reference numeral 1 denotes an internal combustion engine (engine). The engine 1 has a cylinder block 2. The cylinder block 2 is provided with a piston 4 that can reciprocate inside the cylinder block 2. A combustion chamber 5 is formed above the piston 4.

  A cylinder head 3 is provided above the cylinder block 2. The cylinder head 3 is provided with an intake port 6 and an exhaust port 7. An intake valve 8 is provided at a connection portion between the combustion chamber 5 and the intake port 6. An exhaust valve 9 is provided at a connection portion between the combustion chamber 5 and the exhaust port 7.

  The cylinder head 3 is provided with a spark plug 10 and a fuel injector 11. Fuel is injected into the combustion chamber 5 by the fuel injector 11. The spark plug 10 ignites the air-fuel mixture compressed in the combustion chamber 5.

  An intake manifold 12 is connected to the intake port 6. A surge tank 13 is connected to the intake manifold 12. An intake passage (intake pipe) 14 is connected to the surge tank 13. A throttle valve 15 is provided in the intake pipe 14. An air cleaner 16 is provided upstream of the installation position of the throttle valve 15 in the intake pipe 14.

  An exhaust manifold 17 is connected to the exhaust port 7. An exhaust pipe 18 is connected to the exhaust manifold 17.

  The engine 1 includes a supercharger (turbocharger) 30 as supercharging means. The turbocharger 30 includes a compressor 30a, a turbine 30b, a rotating shaft 30c, and a wastegate valve 30d. The compressor 30 a is provided in the intake pipe 14. The turbine 30 b is provided in the exhaust manifold 17. The compressor 30a and the turbine 30b are connected by a rotating shaft 30c.

  The turbine 30 b is driven to rotate by the energy of exhaust gas supplied through the exhaust manifold 17. As the turbine 30b rotates, the compressor 30a rotates and the intake air is compressed. The intake air supplied to the compressor 30a is compressed by the compressor 30a, so that the temperature rises and becomes high. An air-cooled intake air cooling device (intercooler) 31 for cooling the intake air is provided downstream of the installation position of the compressor 30 a in the intake pipe 14. The hot intake air is cooled by heat exchange with the outside air while flowing through the intercooler 31.

  An exhaust bypass passage 33 for bypassing exhaust gas supplied to the turbine 30b is connected to the exhaust manifold 17. One end of the exhaust bypass passage 33 is connected to the upstream side of the exhaust manifold 17 relative to the installation position of the turbine 30b. The other end of the exhaust bypass passage 33 is connected to the exhaust pipe 18. A waste gate valve 30 d is provided in the exhaust bypass passage 33. The exhaust bypass passage 33 is opened and closed by the wastegate valve 30d.

  When the rotation speed of the compressor 30a increases too much and the pressure of the compressed intake air becomes higher than a predetermined supply pressure, the wastegate valve 30d is opened. As a result, part of the exhaust gas flowing through the exhaust manifold 17 flows to the exhaust pipe 18 through the exhaust bypass passage 33. In this case, the amount of exhaust gas supplied to the turbine 30b is reduced, and an increase in the rotational speed of the turbine 30b and the compressor 30a is suppressed. As a result, an excessive increase in the intake pressure is suppressed.

  In the intake pipe 14, a water injector 34 is provided between the installation position of the compressor 30 a and the installation position of the intercooler 31. Water is injected into the intake pipe 14 by the water injector 34. A water tank 36 is provided in a vehicle (not shown) on which the engine 1 is mounted. The water tank 36 and the water injector 34 are connected via a water pipe 38. A water pump 35 is provided in the water pipe 38. The water 37 stored in the water tank 36 is pumped by the water pump 35 and supplied to the water injector 34.

  A pressurized air temperature switch 39 is provided between the installation position of the compressor 30 a and the installation position of the water injector 34 in the intake pipe 14. The pressurized air temperature switch 39 outputs an ON signal or an OFF signal according to the intake air temperature. When the detected intake air temperature is higher than a preset value of the intake air temperature, an ON signal is output from the pressurized air temperature switch 39. On the other hand, when the detected temperature of the intake air is equal to or lower than the set value of the intake air temperature, an OFF signal is output from the pressurized air temperature switch 39.

  The vehicle is provided with a vehicle control unit 40 having an ECU (Electronic Control Unit) that controls each part of the vehicle. A pressurized air temperature switch 39 is connected to the vehicle control unit 40, and a signal output from the pressurized air temperature switch 39 is input to the vehicle control unit 40. A water injector 34 is connected to the vehicle control unit 40, and the water injector 34 is controlled by the vehicle control unit 40.

  FIG. 2 is a time chart of this embodiment. FIG. 3 is a flowchart showing the operation of the present embodiment.

In FIG. 2, reference numeral 100 indicates the state of the drive signal for the water injector 34. Reference numeral 101 indicates an output of the pressurized air temperature switch 39. Reference numeral 102 indicates the temporal transition of the intake air temperature. Reference numeral 103 indicates a temporal transition of the pressure of the intake air. Symbol A ₀ indicates a preset value of the intake air temperature. Reference numeral t1 indicates a point at which supercharging by the turbocharger 30 is started when the vehicle is accelerated.

In the present embodiment, when the intake air temperature 102 is high, the pressurized intake air is cooled. When the intake air temperature 102 is higher than the intake air temperature setting value A ₀ , water is injected from the water injector 34 in response to an injection command from the vehicle control unit 40.

  Symbol Ton indicates a period during which the drive signal 100 is ON by the vehicle control unit 40 (hereinafter referred to as ON time). In the ON time Ton, water is injected into the intake pipe 14 by the water injector 34 in response to the drive signal 100 turned ON. A symbol Toff indicates a period during which the drive signal 100 is OFF (hereinafter referred to as OFF time). In the OFF time Toff, water injection by the water injector 34 is stopped.

During supercharging, the flowchart shown in FIG. 3 is executed at predetermined time intervals. In step S10, it is determined whether or not an ON signal is output from the pressurized air temperature switch 39. As described above, the ON signal is output from the pressurized air temperature switch 39 when the intake air temperature 102 (FIG. 2) is higher than the set value A _{0 of the} intake air temperature.

As shown in FIG. 2, when supercharging is started at time t1, the intake air pressure 103 rises, and the intake air temperature 102 begins to rise in conjunction therewith. At time t1 between the supercharging is started to the time t2, the temperature 102 of the intake air is lower than the set value A ₀ of the intake air temperature. Therefore, the output 101 of the pressurized air temperature switch 39 is turned off. In this case, a negative determination is made in step S10, so this control flow is reset and the flowchart shown in FIG. 3 is executed again.

At time t2, the intake air temperature 102 reaches the set value A ₀ of the intake air temperature. As a result, as indicated by reference numeral 101, an ON signal is output from the pressurized air temperature switch 39 to the vehicle control unit 40 at time t2. In this case, since a positive determination is made in step S10, the process proceeds to step S20.

  In step S20, in response to the output 101 of the pressurized air temperature switch 39 being turned ON, the vehicle control unit 40 determines that the pressurized intake air is currently in a period to be cooled. In the example shown in FIG. 2, the period from time t2 to time t6 is set as a period during which the pressurized intake air is to be cooled. During the period in which the pressurized intake air is to be cooled, the water injection signal is turned on. The water injection signal is a signal for causing the water injection control to be performed by generating an injection command for the water injector 34 in the vehicle control unit 40.

  As described above, in this embodiment, whether or not the intake air pressurized by the turbocharger 30 is cooled based on the output 101 of the pressurized air temperature switch 39 (period in which the pressurized intake air is to be cooled). Is determined. The period during which the pressurized intake air is to be cooled is determined by the cooling period determination means (vehicle control unit 40). The vehicle control unit 40 sets a period during which the output 101 of the pressurized air temperature switch 39 is ON as a period during which the pressurized intake air is to be cooled. In the period in which the pressurized intake air is to be cooled, the vehicle control unit 40 outputs a drive signal 100 to the water injector 34. The water injector 34 ejects water in response to the drive signal 100.

  As shown in FIG. 2, the drive signal 100 for the water injector 34 is alternately turned on and off. That is, after the water is injected at the ON time Ton, the operation of stopping the water injection at the OFF time Toff is repeated. As a result, the water spray is sandwiched between the high-temperature intake air from the upstream side and the downstream side of the water spray in the intake air flow direction of the intake pipe 14. For this reason, mixing of water spray and hot intake air is promoted. Therefore, evaporation of the injected water is promoted as compared with the case where water is continuously injected.

  In the present embodiment, the ON time Ton when water is injected from the water injector 34 is increased to a predetermined pressure after the drive signal 100 for the water injector 34 is turned ON. Is set to the time until. As will be described later, the predetermined pressure is set to a pressure at which the shape of the water spray becomes a stable shape. As a result, as described below, the angle at which the water spray spreads (spray angle) increases, so that the water and the intake air are easily mixed, and the evaporation of the water is promoted. In addition, since the sprayed water is sufficiently atomized, evaporation is promoted.

  FIG. 4 is an enlarged view of the water injector 34. The water injector 34 includes a main body 45 and a small-diameter portion 49 provided at the tip of the main body 45. The small diameter portion 49 is formed with a smaller diameter than the main body 45. The small-diameter portion 49 is provided with an injection hole 41 that is a passage for water that is injected from the water injector 34 into the external space. A valve 43 that can reciprocate in the axial direction of the main body 45 is provided inside the main body 45. A water passage 46 is formed between the main body 45 and the valve 43. The valve 43 is reciprocated in the axial direction of the main body 45 by a drive mechanism (not shown). In the direction in which the valve 43 reciprocates, the direction toward the nozzle hole 41 is indicated by an arrow X (hereinafter, this direction is referred to as the X direction).

  A valve seat 44 is provided on the inner peripheral surface of the main body 45 at the connection portion between the main body 45 and the small diameter portion 49. FIG. 4 shows a state where the valve 43 is in contact with the valve seat 44 (a state when water injection is stopped). A water reservoir 42 is formed inside the small diameter portion 49. The nozzle hole 41 communicates the water reservoir 42 and the external space of the water injector 34. The nozzle hole 41 opens in a direction substantially orthogonal to the X direction.

  FIG. 5 is a diagram illustrating a state of the water injector 34 at the time of water injection. When water is injected, the valve 43 is moved in the direction opposite to the X direction by a drive mechanism (not shown). As a result, the valve 43 is separated from the valve seat 44 and the water passage 46 and the water reservoir 42 are in communication with each other. The water pumped to the water injector 34 by the water pump 35 (FIG. 1) via the water pipe 38 (FIG. 1) flows through the water passage 46 and into the water reservoir 42 as indicated by an arrow 47. The high-pressure water that has flowed into the water reservoir 42 passes through the nozzle hole 41 and is injected into the external space. The jetted water becomes a water spray 48.

  An arrow indicated by a symbol Y indicates the flow direction of intake air (downstream side in the intake pipe 14). In this embodiment, water is injected toward the downstream side (side closer to the engine 1) in the direction of intake air flow. The symbol α indicates the spray angle of the water spray 48. Although the spray angle α indicates an angle in the vertical direction in the figure, the water spray 48 has a substantially circular cross-sectional shape in a direction orthogonal to the water injection direction (direction indicated by the arrow Y). For this reason, the spread angle of the water spray 48 in the left-right direction (direction perpendicular to the paper surface) is also a value indicated by the symbol α.

In the present embodiment, as described above, the ON time Ton when the drive signal 100 for the water injector 34 is turned ON and water is injected is the pressure of water (water) that is injected after the drive signal 100 is turned ON. It is set to the time until the pressure of the storage part 42 rises to a predetermined pressure (see Pw in FIG. 6). As described below with reference to FIG. 6, the predetermined pressure can be set to a minimum pressure at which the water spray 48 has a stable shape, for example. Here, that the shape of the water spray 48 is stable means that the spray angle α becomes a predetermined angle (see α _{0 in} FIG. 6) set in advance.

FIG. 6 is a diagram showing the relationship between the pressure of water to be injected and the spray angle α. Reference symbol Pw indicates the predetermined pressure. The symbol α ₀ indicates the predetermined angle. Reference numeral 400 indicates a correspondence relationship between the pressure of water sprayed by the water injector 34 and the spray angle α. As indicated by reference numeral 400, the spray angle α increases as the pressure of the injected water increases. When the pressure of the injected water rises and reaches the predetermined pressure Pw, the spray angle α does not change even if the water pressure further increases, and the spray angle α generally changes at the predetermined angle α ₀ . . The predetermined pressure Pw is thus set to a lower limit value in a pressure region where the spray angle α changes approximately at the predetermined angle α ₀ .

  The ON time Ton is set based on the result of an experiment, for example. The ON time Ton is set to the time from when the drive signal 100 to the water injector 34 is turned ON as described above until the pressure of the water jetted rises to the predetermined pressure Pw as follows. by.

  When water is injected from the water injector 34, the larger the spray angle α shown in FIG. This is because as the spray angle α is larger, the injected water spreads over a wider area and becomes easier to mix with the intake air. As described with reference to FIG. 6, the spray angle α increases as the water pressure increases. For this reason, the evaporation of water is promoted as the ON time Ton is set to a large value and the pressure of the injected water increases. Further, when the pressure of the water to be jetted becomes high, the water is sufficiently atomized so that the evaporation of water is promoted.

However, as shown in FIG. 6, the spray angle α does not increase above the predetermined angle α ₀ even when the pressure of the water to be injected becomes higher than the predetermined pressure Pw. Therefore, even if water is jetted longer than the time during which the water pressure rises to the predetermined pressure Pw, an improvement in the evaporation effect due to an increase in the spray angle α cannot be expected. In addition, if the water is sprayed for a long time, the water spray 48 and the intake air are hardly mixed. This is because the length of the spray direction of the water spray 48 indicated by the symbol L in FIG. As the length L in the injection direction of the water spray 48 becomes longer, the water spray 48 becomes less likely to be mixed with high-temperature intake air that flows upstream and downstream of the water spray 48 in the intake air flow direction indicated by the symbol Y. In this case, the water spray 48 is difficult to evaporate.

  Therefore, in the present embodiment, the ON time Ton is set to a time from when the water injection is started until the pressure of the injected water rises to the predetermined pressure Pw. As a result, the spray angle α becomes sufficiently large and the water particles ejected from the water injector 34 become sufficiently small, so that evaporation of the ejected water (water spray 48) is promoted. Further, the water spray 48 is sufficiently mixed with high-temperature intake air flowing upstream and downstream of the water spray 48 in the intake air flow direction of the intake pipe 14. For this reason, evaporation of the water spray 48 is promoted.

  Next, the OFF time Toff, which is a period during which water injection is stopped, will be described. After the water injection is performed at the ON time Ton as described above, the water injection is stopped at the OFF time Toff. By repeating the ON time Ton and the OFF time Toff alternately, water is injected between a period during which water is jetted (first period) and a period during which water is jetted next (third period). A period (second period) during which no injection is performed is provided. As a result, a high-temperature intake layer is maintained between the water spray 48 injected in the first period and the water spray 48 injected in the third period. As a result, the hot spray is easily taken into the water spray 48, and evaporation is promoted. The OFF time Toff is set to a value that promotes the evaporation of water more effectively as described below.

  The value of the OFF time Toff varies depending on various factors. For example, the amount of water injection during one ON time Ton by the water injector 34 (hereinafter referred to as each injection amount (see reference symbol W in FIG. 7 described later)), engine speed, supercharging pressure, and intake air temperature. The OFF time Toff is set to a different value according to the target value of the amount of descent (hereinafter referred to as the target amount of descent Ctrg). The OFF time Toff is set based on the result of an experiment, for example. In this case, as will be described below with reference to FIGS. 7 to 9, the OFF time Toff is a water injection amount per unit time (hereinafter referred to as a unit time injection amount) within a range in which the target drop amount Ctrg can be realized. (See symbol WA in FIG. 7)) is set to a minimum value.

  When the OFF time Toff changes, easiness of water evaporation (e.g., time required for evaporation) changes due to, for example, a difference in ease of mixing between the water spray 48 and the intake air. The OFF time Toff is a time interval from the end of the ON time Ton to the stop of water injection until the start of water injection at the next ON time Ton. The larger the OFF time Toff is set, the higher the amount of hot intake air that is sandwiched between the water spray 48 injected at the first ON time Ton and the water spray 48 injected at the second ON time Ton. Will increase. For this reason, as the OFF time Toff is set to a larger value, the evaporation of the water spray 48 is promoted, and the amount of intake air temperature drop (hereinafter referred to as intake air temperature drop amount (see symbol C in FIG. 7)) increases. It is considered to be.

  However, when the OFF time Toff is set to a value larger than necessary, the amount of water injected is insufficient with respect to the amount of hot intake air, so that the intake air temperature cannot be lowered sufficiently. . In this case, the intake air temperature drop amount C becomes a small value. Even if the respective injection amounts W are the same, the intake air temperature drop amount C varies depending on the value of the OFF time Toff as described above. Therefore, as shown in FIG. 7, the OFF time Toff (hereinafter referred to as optimum OFF) when the value of the intake air temperature decrease amount C becomes the maximum value (hereinafter referred to as the maximum decrease amount Cmax) with respect to a certain arbitrary injection amount W. Time ZA).

  FIG. 7 is a diagram showing combinations of each injection amount W, the maximum drop amount Cmax under the conditions of each injection amount W, and the optimum OFF time ZA. In FIG. 7, reference signs W <b> 1, W <b> 2, etc. indicate set values of the respective injection amounts W. Symbols C1, C2, etc. indicate the value of the maximum drop amount Cmax under the condition of each injection amount W. Symbols Z1, Z2, etc. indicate the values of the optimum OFF time ZA at which the maximum drop amount Cmax is obtained under the conditions of each injection amount W.

  When determining the optimum OFF time ZA, as described below, the value of the OFF time Toff is varied to various values under the condition that the value of each injection amount W is set to one value. As a result, the optimum OFF time ZA in which the intake air temperature decrease amount C becomes the maximum decrease amount Cmax is obtained by experiment.

The procedure of the experiment will be described with reference to FIG. 8, taking as an example the case where the experimental result shown in No. 1 is obtained in FIG. In FIG. 8, a symbol Z _1n (n = 1, 2, 3,...) Indicates a set value of the OFF time Toff. Symbol C _1n (n = 1, 2, 3...) Indicates the value of the intake air temperature drop amount C obtained as a result of the experiment with respect to the set value Z _1n of the OFF time Toff.

As shown in FIG. 8, the setting value Z _1n of the OFF time Toff is varied to various values under the condition that the value of each injection amount W is set to W1. Of the intake air temperature drop amount C _1n obtained as a result, the maximum value C1 is set as the maximum drop amount Cmax. In this case, the OFF time Toff of the set value Z _1n value Z1 when the maximum value C1 of the intake air temperature drop C _1n is obtained, is set to an optimum OFF time ZA. The value C1 of the maximum drop amount Cmax and the value Z1 of the optimum OFF time ZA are associated with the value W1 of each injection amount W and stored as the No1 experimental result.

When the experimental result shown in No. 2 in FIG. 7 is obtained, as shown in FIG. 9, the intake air temperature drop amount C is obtained by the same procedure as described above under the condition that the value of each injection amount W is set to W2. A maximum value C2 of _2n is obtained. The maximum value C2 of the intake air temperature decrease amount C _2n is set as the value of the maximum decrease amount Cmax. Also, the set value Z _2n values Z2 OFF time Toff of when the maximum value C2 of the intake air temperature drop C _2n is obtained, is set to the value of the optimum OFF time ZA. Similarly, the above experiment is performed under the conditions of the set values (W3, W4...) Of the respective injection amounts W in FIG. 7, and the combinations shown in FIG. 7 are set based on the respective experimental results.

  In FIG. 7, the symbol WA (WA1, WA2, etc.) indicates the unit time injection amount. The unit time injection amount WA is calculated based on each injection amount W, ON time Ton (not shown), and optimum OFF time ZA.

  Next, a method for determining the OFF time Toff will be described. When the pressurized intake air is cooled, for example, the target descent amount Ctrg is determined based on the temperature of the pressurized intake air. When the target descent amount Ctrg is set, the combination in which the value of the maximum descent amount Cmax satisfies the target descent amount Ctrg among the combinations of the respective injection amounts W, the maximum descent amount Cmax, and the optimum OFF time ZA shown in FIG. Is selected. When there are a plurality of selected combinations, the combination having the smallest unit time injection amount WA is employed.

  For example, if the values of the maximum drop amount Cmax that can realize the target drop amount Ctrg are C1 and C3 (C1 and C3 may be the same value or different values), No1 and No3 A combination is selected. In this case, both unit time injection amounts WA are compared. When the unit time injection amount WA3 in the No3 combination is smaller than the unit time injection amount WA1 in the No1 combination, the No3 combination is finally selected. In this case, the value of the OFF time Toff is set to Z3.

  Thus, the unit time injection amount WA can be reduced within a range where the target drop amount Ctrg can be realized. The engine speed and the boost pressure are detected by an engine speed detector and a boost pressure detector (not shown), respectively.

  According to the present embodiment, the water injection is intermittently performed during the period in which the pressurized intake air is to be cooled, thereby promoting the evaporation of the injected water. The ON time Ton, which is a period during which water is injected, is set to a time from when the water injection is started until the pressure of the water to be injected rises to the predetermined pressure Pw. Thereby, mixing of the injected water and the intake air is promoted, and the injected water is sufficiently atomized, so that the evaporation of water is more efficiently promoted. As a result, the injected water is prevented from remaining in the intake pipe 14 without being evaporated.

  Further, according to the present embodiment, the evaporation of water is promoted as compared with the case where water is continuously injected during the period in which the pressurized intake air is to be cooled. For this reason, the amount of water injection required to lower the temperature of the intake air by the same amount is smaller than when water is continuously injected. Further, by setting the OFF time Toff to a value that minimizes the unit time injection amount WA with respect to the target drop amount Ctrg as described above, the injection amount of water necessary to lower the intake air temperature by the same amount is set. The value is set as small as possible. That is, the intake air temperature can be efficiently lowered with a smaller amount of water injection. Since the amount of water consumed is reduced, the capacity of the water tank 36 can be reduced to reduce the weight. In addition, since the amount of water consumption is reduced, the frequency of water supply is reduced, and the maintenance work is reduced.

  In the present embodiment, the temperature of the intake air flowing into the intercooler 31 is lowered by injecting water upstream from the installation position of the intercooler 31. Thereby, it is suppressed that the intercooler 31 is exposed to high temperature intake air and deteriorates.

  In the present embodiment, the pressurized air temperature switch 39 is provided upstream of the installation position of the water injector 34. For this reason, even if water is injected and the temperature of the intake air downstream of the water injector 34 is lowered, the temperature of the intake air detected by the pressurized air temperature switch 39 is not affected. Thereby, since the temperature of the intake air supplied from the compressor 30a is accurately grasped, it is reliably determined whether or not water injection is necessary.

  In the present embodiment, it is determined whether to cool the pressurized intake air based on the temperature of the intake air. Note that, when supercharging is performed, the temperature rises as the pressure of the intake air rises. Therefore, it is conceivable to determine whether to cool the pressurized intake air based on the pressure of the intake air. . However, as described below, when the above determination is made based on the pressure of the intake air, the injection of water is finished before the temperature of the intake air supplied from the compressor 30a is still sufficiently lowered. There is a problem that it ends up.

In FIG. 2, the symbol P ₀ indicates the value of the intake air pressure 103 at time t2 when the intake air temperature 102 reaches the set value A ₀ of the intake air temperature. As shown in FIG. 2, even if the intake pressure 103 begins to decrease at time t3 due to a decrease in the load on the engine 1, the intake air temperature 102 does not decrease immediately. This is because the compressor 30a, the intake pipe 14, and the like become hot during supercharging. Even if the intake pressure 103 starts to decrease at time t3, the temperatures of the compressor 30a and the intake pipe 14 remain high, so the intake air temperature 102 does not decrease immediately and decreases compared to the intake pressure 103. The timing (time t4) to start the operation is delayed. For this reason, at the time t5 when the intake air pressure 103 decreases to the pressure indicated by the symbol P ₀ , the intake air temperature 102 decreases only to a temperature A ₁ that is higher than the set value A _{0 of the} intake air temperature.

As described above, the intake air temperature 102 is delayed with respect to the intake air pressure 103. Therefore, when it is determined whether or not to cool the pressurized intake air based on whether or not the intake air pressure 103 is equal to or higher than the pressure P ₀ , the intake air temperature 102 is still only up to the temperature A _1. Cooling of the pressurized intake air is terminated in a state where it has not decreased (time t5). If the cooling of the pressurized intake air is finished in such a state that the pressurized intake air still needs to be cooled, knocking is not sufficiently suppressed. Thus, in the present embodiment, it is determined whether or not to cool the pressurized intake air based on the intake air temperature 102. As a result, the occurrence of the problem that the cooling of the pressurized intake air is finished before the intake air temperature 102 has sufficiently decreased is suppressed.

In the present embodiment, the predetermined pressure Pw (FIG. 6) is set to a lower limit value in a pressure region where the spray angle α is approximately changed at the predetermined angle α ₀ . The pressure Pw can be set to the supply pressure of water supplied to the water injector 34. In this case, the water is injected until the supply pressure that is the maximum value of the pressure of the water to be injected is reached. Therefore, the configuration is such that the spray angle α is the maximum value that can surely be taken while water is being injected during the ON time Ton.

  In the present embodiment, water is injected into the intake pipe 14, but the cooling medium to be injected is not limited to water. For example, fuel can be injected into the intake pipe 14 as a cooling medium.

(Modification of the first embodiment)
In this modification, the OFF time Toff is set to the time until the jetted water (water spray 48 in FIG. 5) evaporates. Thereby, since the next water injection is not performed until the injected water evaporates, it is suppressed that the injected water remains in the intake pipe 14.

  The time until the jetted water evaporates varies depending on the conditions. In this modification, the OFF time Toff is set based on the pressure of the intake air, the temperature of the intake air, the amount of water to be injected, and the temperature of the water to be injected. The OFF time Toff is set based on the result of an experiment, for example.

(Second Embodiment)
The second embodiment will be described with reference to FIGS. 10 to 13. In the second embodiment, only differences from the first embodiment will be described.

  In the first embodiment, water is intermittently injected during a period in which the pressurized intake air is to be cooled, whereby water evaporation is promoted and water remains in the intake pipe 14. In the present embodiment, in addition to this, when the outside air temperature is low, control is performed to more reliably suppress the injected water from being evaporated and remaining in the intake pipe 14. This suppresses freezing of water remaining in the intake pipe 14 when the outside air temperature is low.

  In the present embodiment, a parameter for determining whether to cool the pressurized intake air is changed according to the outside air temperature. When the outside air temperature is higher than a predetermined outside air temperature (for example, 0 ° C.) (hereinafter referred to as a high outside air temperature), the pressure is increased based on the temperature of the intake air as in the first embodiment. Whether or not to cool the intake air is determined. On the other hand, when the outside air temperature is equal to or lower than the predetermined outside air temperature (hereinafter referred to as a low outside air temperature), the above determination is performed based on the pressure of the intake air.

  As a result, as will be described in detail below, when the outside air temperature is low, the cooling of the pressurized intake air is finished in a state where the temperature of the intake air is higher than when the cooling of the pressurized intake air is started. It becomes like this. For this reason, even if there is water that has not evaporated in the intake pipe 14 at the time when the injection of water is terminated, the relatively high temperature intake air flows through the intake pipe 14 thereafter, so that the evaporation of the water is promoted. The Therefore, water remaining in the intake pipe 14 is suppressed. As a result, the remaining water is suitably suppressed from freezing.

  FIG. 10 is a schematic configuration diagram of an apparatus according to the present embodiment. A pressurized air temperature sensor 51 is provided instead of the pressurized air temperature switch 39 of the apparatus of the first embodiment (FIG. 1). The pressure of the intake air pressurized by the turbocharger 30 is detected by the pressurized air temperature sensor 51. A pressurized air pressure sensor 52 is provided between the installation position of the compressor 30 a and the installation position of the water injector 34 in the intake pipe 14. The pressure of the intake air pressurized by the turbocharger 30 is detected by the pressurized air pressure sensor 52.

  Outside air temperature detecting means (outside air temperature sensor) 50 is provided in the vicinity of the intercooler 31. The outside air temperature sensor 50 detects the temperature of the outside air. In the present embodiment, the outside air temperature sensor 50 is disposed in the vicinity of the side facing the outside of the vehicle (hereinafter referred to as the vehicle outside side) in the intercooler 31. The reason why the outside air temperature sensor 50 is provided at the above position is that, as will be described below, the intercooler 31 has a high possibility that water will remain and is susceptible to influence when the remaining water freezes. is there.

  Inside the intercooler 31, the intake passage is divided into a plurality of passages having a small diameter. For this reason, there is a high possibility that water remains in the intercooler 31.

  In addition, the intercooler 31 is likely to be affected by freezing, such as an increase in flow path resistance when the remaining water is frozen. This is because the intake passage is narrow inside the intercooler 31 as described above.

  For this reason, in this embodiment, the outside air temperature sensor 50 is installed in the vicinity of the vehicle exterior side in the intercooler 31. Accordingly, it is reliably detected whether or not the intercooler 31 that has a high possibility of remaining water and is likely to be affected when the remaining water is frozen is exposed to low-temperature outside air.

  Instead of the vehicle control unit 40 of the first embodiment, a vehicle control unit 60 is provided. The outside air temperature sensor 50, the pressurized air temperature sensor 51 and the pressurized air pressure sensor 52 are connected to the vehicle control unit 60, and each measurement result is input to the vehicle control unit 60. The water injector 34 is connected to the vehicle control unit 60 and is controlled by the vehicle control unit 60.

  In the present embodiment, a parameter for determining whether to cool the pressurized intake air based on the outside air temperature detected by the outside air temperature sensor 50 is changed. When the outside air temperature is high, it is determined whether to cool the pressurized intake air based on the temperature of the intake air as in the first embodiment (see FIG. 2). On the other hand, at the time of low outside air temperature, the above determination is made based on the pressure of the intake air.

  As a result, as described below, at the low outside air temperature, the cooling of the pressurized intake air is finished at a higher intake air temperature than when the cooling of the pressurized intake air is started. become.

  FIG. 11 is a time chart when it is determined whether or not to cool the pressurized intake air based on the temperature of the intake air at the time of high outside air temperature as in the first embodiment. FIG. 12 is a time chart when it is determined whether or not to cool the pressurized intake air based on the pressure of the intake air at a low outside air temperature.

  Reference numeral 200 in FIG. 11 and reference numeral 300 in FIG. 12 indicate states of drive signals output from the vehicle control unit 60 to the water injector 34, respectively. Similarly to the first embodiment (FIG. 2), water is injected into the intake pipe 14 by the water injector 34 at the ON time Ton. Water injection by the water injector 34 is stopped at the OFF time Toff.

The code | symbol 201 of FIG. 11 and the code | symbol 301 of FIG. 12 each show the state of a water injection signal. Reference numeral 202 in FIG. 11 and reference numeral 302 in FIG. 12 indicate temporal transitions of the intake air temperature, respectively. Reference numeral 203 in FIG. 11 and reference numeral 303 in FIG. 12 indicate temporal transitions of the intake pressure. 11 and 12, symbol A ₂ indicates a preset value for the second intake air temperature. The set value A ₂ of the _second intake air temperature can be the same value as the set value A ₀ of the intake air temperature in the first embodiment. 11 and 12, reference sign P ₁ is a predetermined pressure setting value. 11 and 12, reference numeral t <b> 11 indicates a point at which supercharging is started by the turbocharger 30.

In the present embodiment, at a high outside air temperature, as shown in FIG. 11, it is determined whether to cool the pressurized intake air based on the intake air temperature 202. When the intake air temperature 202 is higher than the set value A ₂ of the second intake air temperature, it is determined that the pressurized intake air is cooled, and the water injection signal 201 is turned on. When the intake air temperature 202 is equal to or lower than the second intake air temperature set value A ₂ , the water injection signal 201 is turned off.

On the other hand, when the outside air temperature is low, as shown in FIG. 12, it is determined whether or not to cool the pressurized intake air based on the intake air pressure 303. If the intake pressure 303 is larger than the pressure set value P ₁ , it is determined that the pressurized intake air is cooled, and the water injection signal 301 is turned ON. When the intake pressure 303 is equal to or lower than the pressure set value P ₁ , the water injection signal 301 is turned off. The pressure setting value P ₁ corresponds to the intake air pressure at time t12 when the intake air temperature 302 reaches the second intake air temperature setting value A ₂ when the intake air pressure 303 and the intake air temperature 302 rise due to supercharging. The value of the pressure 303 is set.

As a result, in the present embodiment, the temperature of the intake air (202 in FIG. 11 and 302 in FIG. 12) at the start of cooling of the pressurized intake air is the same at the time of the high outside air temperature and the low outside air temperature. Although it is configured, the value of the intake air temperature 302 when the cooling of the pressurized intake air at the time of the low outside air temperature is started is not limited to this. The pressure is set so that the intake air temperature (202 in FIG. 11 and 302 in FIG. 12) at the start of cooling of the pressurized intake air at the time of high outside air temperature and at the time of low outside air temperature become different values. can be the value P ₁ is set.

Here, the intake air at the start and end of the period during which the pressurized intake air is cooled when it is determined whether or not the pressurized intake air is cooled based on the intake air pressure 303 at the low outside air temperature. The temperature difference of the temperature 302 will be described. When the intake pressure 303 decreases as the load of the engine 1 decreases, the intake air temperature 302 decreases later than the intake pressure 303. This is because, as explained with reference to FIG. 2 in the first embodiment, the compressor 30a, the intake pipe 14 and the like are at a high temperature during supercharging. Due to a decrease in the load of the engine 1, the intake pressure 303 starts to decrease after reaching a peak at time t13, and reaches the pressure setting value P _{1 at} time t15. On the other hand, the intake air temperature 302 has only decreased to a temperature A ₃ higher than the set value A ₂ of the second intake air temperature at time t15.

As described above, the value (A ₃ ) of the intake air temperature 302 at the time t15 when the cooling of the pressurized intake air is finished is the value of the intake air temperature 302 at the time t12 when the cooling of the pressurized intake air is started. It becomes higher than (set value A ₂ of the second intake air temperature). As a result, relatively high temperature intake air flows through the intake pipe 14 after time t15 when the cooling of the pressurized intake air is finished, and thus water is suppressed from remaining in the intake pipe 14.

  FIG. 13 is a flowchart showing the operation of this embodiment. First, in step S110, the outside air temperature detected by the outside air temperature sensor 50 is read.

  Next, in step S120, it is determined whether or not the outside air temperature is higher than a predetermined outside air temperature.

  As a result of the determination in step S120, if it is determined that the outside air temperature is higher than the predetermined outside air temperature (Yes in step S120), the process proceeds to step S130. In this case, it is determined whether or not to cool the pressurized intake air based on the intake air temperature 202 (FIG. 11) as in the first embodiment.

In step S130, the intake air temperature 202 (pressurized air temperature) detected by the pressurized air temperature sensor 51 is read. Next, in step S140, it is determined whether or not the intake air temperature 202 is higher than the set value A2 of the _second intake air temperature. As shown in FIG. 11, the intake air temperature 202 is higher than the set value A ₂ of the second intake air temperature between time t12 and time t16.

As a result of the determination in step S140, when it is determined that the intake air temperature 202 is higher than the set value A2 of the _second intake air temperature (Yes in step S140), the process proceeds to step S170. In step S170, the water injection signal 201 is set to ON in the vehicle control unit 60. When the water injection signal 201 is turned on, the vehicle control unit 60 starts outputting the drive signal 200 to the water injector 34. The water injector 34 injects water in response to the drive signal 200.

On the other hand, the result of the determination in step S140, the temperature 202 of the intake air when it is determined to be equal to or less than the set value A ₂ of the second intake air temperature (step S140: No), the present control flow is ended.

  As a result of the determination in step S120, when it is determined that the outside air temperature is equal to or lower than the predetermined outside temperature (No in step S120), the process proceeds to step S150. In this case, it is determined whether to cool the pressurized intake air based on the intake air pressure 303 (FIG. 12).

In step S150, the intake air pressure 303 (pressurized air pressure) detected by the pressurized air pressure sensor 52 is read. Next, in step S160, the pressure 303 of the intake whether larger than the set value P ₁ of the pressure is determined. As shown in FIG. 12, the intake pressure 303 is greater than the set pressure value P ₁ between time t12 and time t15.

As a result of the determination in step S160, when it is determined that the pressure 303 of the intake air is greater than the pressure set value P ₁ (Yes in step S160), the process proceeds to step S170. In step S170, the water injection signal 301 is set to ON in the vehicle control unit 60. When the water injection signal 301 is turned ON, the vehicle control unit 60 starts outputting the drive signal 300 to the water injector 34. The water injector 34 injects water in response to the drive signal 300.

On the other hand, the result of the determination in step S160, the pressure 303 of the intake air when it is determined to be equal to or less than the set value P ₁ of the pressure (step S160: No), the present control flow is ended.

  In the present embodiment, when the outside air temperature is higher than the predetermined outside air temperature (Yes at Step S120), it is determined whether to cool the pressurized intake air based on the intake air temperature 202 (Step S130). , S140). On the other hand, when the outside air temperature is equal to or lower than the predetermined outside air temperature (No at Step S120), it is determined whether to cool the pressurized intake air based on the intake air pressure 303 (Steps S150 and S160). .

As a result, as described above with reference to FIG. 12, the value (A ₃ ) of the intake air temperature 302 at time t15 when the cooling of the pressurized intake air is finished is increased at the low outside air temperature. The intake air temperature 302 becomes higher than the value of the intake air temperature 302 at the time t12 when the intake air cooling starts (the second intake air temperature setting value A ₂ ). For this reason, when the outside air temperature is low, since the relatively hot intake air flows through the intake pipe 14 after time t15 when the cooling of the pressurized intake air is finished, the evaporation of water is promoted. Therefore, it is suppressed that water remains in the intake pipe 14 after the water injection is finished. As a result, problems due to freezing of the remaining water are suppressed.

  In the present embodiment, the outside air temperature sensor 50 is installed in the vicinity of the outside of the vehicle in the intercooler 31. As a result, the outside air temperature in the vicinity of the portion that is particularly likely to be affected by water and that is likely to be affected when the remaining water is frozen is detected (step S110). When the outside air temperature is equal to or lower than the predetermined outside air temperature (No at Step S120), control is performed to end the cooling of the pressurized intake air while the intake air temperature 302 is high (Steps S150 and S160). As a result, it is possible to prevent the water from remaining in the intercooler 31 that is likely to remain, especially when the remaining water is frozen, and the occurrence of problems due to the remaining water being frozen. .

  The control of the present embodiment is highly effective when the turbocharger 30 is set to perform high supercharging from a state where the engine speed is relatively low. The turbocharger 30 is set as described above, for example, when supercharging is performed as a means for compensating for a decrease in the output when the engine 1 is reduced in exhaust volume. Generally, when supercharging is performed in order to obtain a high output, the supercharging pressure is set to be higher on the higher engine speed side. On the other hand, when the engine 1 is reduced for the purpose of improving fuel consumption, etc., when the supercharging is performed for the purpose of compensating for the output reduction due to the reduced displacement, the engine speed is relatively low. It is assumed that high supercharging is performed.

  In this case, high supercharging is often performed while the vehicle speed is low. Since the traveling wind is weak during low speed traveling, the cooling effect of the intercooler 31 by the traveling wind cannot be expected so much with respect to the intake air that has become hot due to high supercharging. For this reason, the opportunity of the injection of the water for cooling intake air will increase, and possibility that the injected water will remain in the intake pipe 14 becomes high. Further, there is a high possibility that the vehicle is stopped in a short time from the low-speed traveling state, and the engine 1 is stopped immediately thereafter. When the engine 1 is stopped in a short time from the state of high supercharging and low speed running, the engine 1 is stopped immediately after the water injection is finished, and water can remain in the intake pipe 14. Increases nature. When water remains in the intake pipe 14 as described above, if the outside air temperature is low, a problem due to freezing of the remaining water occurs.

  On the other hand, in the present embodiment, at the time of low outside air temperature, the cooling of the intake air pressurized in a state where the intake air temperature 302 is relatively high is terminated, and control for promoting the evaporation of water is performed. For this reason, even when the engine 1 is stopped in a short time from the low-speed running state as described above, when the supercharging is performed for the purpose of compensating for the output decrease due to the reduction in the engine displacement, the engine 1 It is possible to prevent water from remaining in the intake pipe 14 after the stop. As a result, the occurrence of problems due to freezing of the remaining water is suppressed.

(Modification of the second embodiment)
In the second embodiment, control is performed to end the cooling of the pressurized intake air when the temperature of the intake air 302 is higher than that at the start of cooling of the pressurized intake air at a low outside air temperature. As a method, it was determined whether or not to cool the pressurized intake air based on the intake air pressure 303 at a low outside air temperature. Instead, in this modification, it is determined whether or not to cool the pressurized intake air based on the intake air temperature 302 at a low outside air temperature. The determination value when determining the end of cooling of the pressurized intake air is set to a larger value than the determination value when determining the start of cooling of the pressurized intake air.

Control at the time of high outside air temperature is the same as that in the second embodiment. That is, as shown in FIG. 11, when the cooling of the pressurized intake air is started (time t12), the determination value of the intake air temperature 202 and the intake air when the cooling of the pressurized intake air is finished (time t16). The determination value for the temperature 202 is set to the same value (second intake temperature setting value A ₂ ).

On the other hand, when the cooling of the pressurized intake air is started at a low outside air temperature, the second intake air temperature setting value A ₂ is used as the determination value of the intake air temperature 302 (FIG. 12), and the intake air temperature 302 is increased. When the cooling of the pressurized intake air is finished, a preset value of the third intake air temperature set as the determination value is used. The set value of the third intake air temperature is set to a value larger than the set value A ₂ of the second intake air temperature. The set value of the third intake air temperature can be set, for example, to a value indicated by a symbol A ₃ in FIG.

In this case, as shown in FIG. 12, at the time of low outside air temperature, the value of the intake air temperature 302 (the third intake air temperature setting value A ₃ ) when the cooling of the pressurized intake air is finished is increased. The intake air temperature 302 becomes higher than the value of the intake air temperature 302 (second intake air temperature setting value A ₂ ) at the start of cooling.

  In the present embodiment, water is injected into the intake pipe 14, but the cooling medium to be injected is not limited to water. For example, fuel can be injected into the intake pipe 14 as a cooling medium.

It is a schematic block diagram of the apparatus which concerns on 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is a time chart of 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is a flowchart which shows operation | movement of 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is an enlarged view of the water injector in 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is a figure which shows the state at the time of the injection of the water injector in 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is a figure for demonstrating the relationship between a water pressure and a spray angle. It is a figure for demonstrating the setting method of OFF time in 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is another figure for demonstrating the setting method of OFF time in 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is another figure for demonstrating the setting method of OFF time in 1st Embodiment of the control apparatus of the internal combustion engine of this invention. It is a schematic block diagram of the apparatus which concerns on 2nd Embodiment of the control apparatus of the internal combustion engine of this invention. In the second embodiment of the control device for an internal combustion engine of the present invention, it is a time chart when it is determined whether to inject water based on the temperature of intake air. In the second embodiment of the control device for an internal combustion engine of the present invention, it is a time chart when it is determined whether to inject water based on the pressure of intake air. It is a flowchart which shows operation | movement of 2nd Embodiment of the control apparatus of the internal combustion engine of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder block 3 Cylinder head 4 Piston 5 Combustion chamber 6 Intake port 7 Exhaust port 8 Intake valve 9 Exhaust valve 10 Spark plug 11 Fuel injector 12 Intake manifold 13 Surge tank 14 Intake pipe 15 Throttle valve 16 Air cleaner 17 Exhaust manifold 18 Exhaust Pipe 30 Turbocharger 30a Compressor 30b Turbine 30c Rotating shaft 30d Westgate valve 31 Intercooler 33 Exhaust bypass passage 34 Water injector 35 Water pump 36 Water tank 37 Water 38 Water piping 39 Pressurized air temperature switch 40 Vehicle control unit 41 Injection hole 42 Water storage Portion 43 Valve 44 Valve seat 45 Main body 46 Water passage 48 Water spray 49 Small diameter portion 50 Outside air temperature sensor 51 Pressurized air temperature sensor 52 Pressurized air pressure sensor DESCRIPTION OF SYMBOLS 0 Vehicle control part 100 Drive signal with respect to water injector 101 Output of pressurized air temperature switch 102 Intake air temperature 103 Intake pressure 200 Intake pressure 200 Drive signal with water injector 201 Water injection signal state 202 Intake temperature 203 Intake pressure 300 Drive with water injector Signal 301 Water injection signal state 302 Intake temperature 303 Intake pressure Ton ON time Toff OFF time A ₀ Intake temperature set value A ₂ Second intake temperature set value P ₁ Pressure set value W Each injection amount WA Unit Time injection amount C Intake temperature drop amount Cmax Maximum drop amount Z OFF time set value ZA Optimum OFF time

Claims (7)

An injection device for injecting a cooling medium for cooling the intake air pressurized by the supercharger downstream of the installation position of the supercharger in the intake path of the internal combustion engine;
Cooling period determination means for determining a period during which the pressurized intake air is to be cooled,
The period during which the pressurized intake air is to be cooled includes a first period during which the cooling medium is injected, a second period during which the cooling medium is not injected following the first period, and the second period. look including the subsequent third period which the cooling medium is injected into,
The period during which the cooling medium is injected is set to a time from when the injection of the cooling medium is started until the pressure of the injected cooling medium reaches a predetermined pressure. A control device for an internal combustion engine. The control apparatus for an internal combustion engine according to claim 1,
The cooling medium is a period which is not injected, intake period in which the cooling medium is not ejected against the set value of the injection quantity of the cooling medium in the period in which the cooling medium is injected is pressurized the pressure when it is set A control device for an internal combustion engine, characterized in that it is set on the basis of the temperature drop amount of the engine. The control apparatus for an internal combustion engine according to claim 2 ,
The injection amount per unit of the cooling medium time, the period in which the cooling medium is Ru is injected, the injection amount of the cooling medium in the period in which the cooling medium is injected, and the cooling medium is determined based on the period which is not injected ,
The cooling medium capable of realizing the target value of the pressure drop of the pressurized intake air during a period when the cooling medium is not injected when the target value of the pressure drop of the pressurized intake air is set. A control device for an internal combustion engine, characterized by being set based on an injection amount per unit time . The control apparatus for an internal combustion engine according to claim 1 ,
The period during which the cooling medium is not injected is set to a time until the injected cooling medium evaporates . The control apparatus for an internal combustion engine according to any one of claims 1 to 4 ,
The cooling period determining means includes an outside air temperature detecting means for detecting the temperature of the outside air,
When the temperature of the outside air detected by the outside air temperature detecting means is equal to or lower than a predetermined outside air temperature, the pressurized intake air at the start of a period for cooling the pressurized intake air A control device for an internal combustion engine , wherein the end of a period during which the pressurized intake air is to be cooled is determined in a state where the temperature of the pressurized intake air is higher than the temperature of the internal combustion engine. The control apparatus for an internal combustion engine according to claim 5 ,
The cooling period determination unit, when the temperature of the outside air detected by the front Kigaiki temperature detecting means is equal to or less than the predetermined outside air temperature, the pressurized on the basis of the pressure of the intake air pressurized control apparatus for an internal combustion engine, wherein the determining the period to be cooled intake air. The control apparatus for an internal combustion engine according to claim 5 or 6,
Wherein the downstream side of the injection position of the cooling medium by the injector in the intake path, intake air cooling device for cooling is provided an air intake of the pressurized,
The control device for an internal combustion engine, wherein the outside air temperature detecting means is provided in the vicinity of the intake air cooling device.

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