JP2012127275A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of supplying efficiently the cylinders with active species produced in a suction passage.SOLUTION: The internal combustion engine is equipped with a supercharger 42 installed in the suction passage 41, a suction air collector 45 installed in the suction passage 41 downstream of the supercharger 42, suction passage 41 between the supercharger 42 and the suction air collector 45, or an intercooler 43 installed inside the suction air collector 45, a bypass passage 47 whose one end is connected with the suction passage 41 downstream of the supercharger 42 in such a manner as detouring the intercooler 43 and other end is connected with the suction air collector 45, an active species generator 472 installed in the bypass passage 47 directly upstream of the suction air collector 45 and generating an active species which enhances the firing performance of the mixture gas, a bypass opening/closing valve 471 installed in the bypass passage 47 upstream of the active species generator 472 and opening and closing the bypass passage 47, and a suction opening/closing valve 44 installed in the suction passage 41 directly upstream of the suction air collector 45.

Description

  The present invention relates to an internal combustion engine.

  A conventional internal combustion engine uses a spark ignition combustion (Spark Ignition; hereinafter referred to as “SI combustion”) or a premixing that is combusted by a spark ignition by a spark plug according to an operating state. It switched to either compression ignition combustion (Homogeneous Charge Compression Ignition; hereinafter referred to as “HCCI combustion”). The intake system is provided with a supercharger, an intercooler, and an intercooler bypass passage, and when performing HCCI combustion, the intake air compressed by the supercharger is controlled to flow to the bypass passage, so that the intake air is not cooled. Were supplied to each cylinder.

JP 2007-16682 A

  In order to improve the ignitability of the air-fuel mixture during HCCI combustion, it is effective to previously contain radicals (chemically active species) such as ozone in the air-fuel mixture. Therefore, it is conceivable to generate or supply radicals in the intake system.

  However, for example, in the above-described conventional internal combustion engine, if radicals are to be supplied through the bypass passage, a part of the supplied radicals flow backward to the intercooler side, so that the radicals cannot be efficiently supplied to each cylinder. It was.

  The present invention has been made paying attention to such problems, and an object thereof is to efficiently supply radicals generated or supplied in an intake system to each cylinder.

  The present invention relates to a supercharger provided in an intake passage, an intake collector provided in an intake passage downstream of the supercharger, an intake passage between the supercharger and the intake collector, or an intake collector An intercooler provided inside, a bypass passage with one end connected to the intake passage downstream of the supercharger and the other end connected to the intake collector so as to bypass the intercooler, and a bypass immediately upstream of the intake collector An active species generator that generates active species that improve the ignitability of the air-fuel mixture, and a bypass on-off valve that opens and closes the bypass passage provided in the bypass passage upstream of the active species generator; An internal combustion engine comprising: an intake opening and closing valve provided in an intake passage immediately upstream of an intake collector in a bypassed portion bypassed by the bypass passage, and opening and closing the intake passage of the bypassed portion It is.

  According to the present invention, the intake opening / closing valve is provided in the intake passage immediately upstream of the intake collector so that the space volume from the intake opening / closing valve to the intake collector is as small as possible.

  In this way, by reducing the space volume from the intake opening / closing valve to the intake collector, if the intake opening / closing valve is closed when supplying the active species from the active species generator provided in the bypass passage immediately upstream of the intake collector, It is possible to suppress the intake air including radicals supplied to the intake collector through the bypass passage from flowing backward to the intake passage. Therefore, it is possible to suppress the intake air supplied to the intake collector from stagnation in the intake passage between the intake opening / closing valve and the intake collector. Therefore, radicals generated by the intake reformer and supplied to the intake collector can be efficiently supplied from the intake collector to each cylinder.

1 is a schematic configuration diagram of an internal combustion engine according to a first embodiment of the present invention. 3 is an operation mode switching map according to the first embodiment of the present invention. It is a flowchart explaining the operation mode switching control by 1st Embodiment of this invention. It is the figure which showed simply the flow of the intake air in each operation mode by 1st Embodiment of this invention. It is a schematic block diagram of the internal combustion engine by 2nd Embodiment of this invention. It is the figure which showed simply the flow of the intake air in each operation mode by 2nd Embodiment of this invention. It is a schematic block diagram of the internal combustion engine by 3rd Embodiment of this invention.

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

(First embodiment)
FIG. 1 is a schematic configuration diagram of an internal combustion engine (hereinafter referred to as “engine”) 1 according to a first embodiment of the present invention. The engine 1 is configured so that the combustion method can be switched to SI combustion or HCCI combustion according to the operating state. Hereinafter, details of the engine 1 will be described.

  The engine 1 includes a cylinder block 2, a cylinder head 3, an intake device 4, an exhaust device 5, and a controller 6.

  A plurality of cylinders 21 are formed in the cylinder block 2. Inside the cylinder 21, a piston 22 that reciprocates within the cylinder 21 in response to combustion pressure is housed. A piston pin 24 for attaching one end of a connecting rod 23 is inserted into the piston 22.

  Moreover, the cylinder block 2 supports the crankshaft 25 rotatably. The crankshaft 25 converts the reciprocating motion of the piston 22 into rotational motion via the connecting rod 23.

  The cylinder head 3 is attached to the upper surface of the cylinder block 2 and forms a part of the combustion chamber 26 together with the cylinder 21 and the piston 22.

  The cylinder head 3 includes an intake port 31, an exhaust port 32, an intake valve 33, an exhaust valve 34, an intake valve variable valve operating device 35, an exhaust valve variable valve operating device 36, an ignition plug 37, a fuel And an injection valve 38.

  The intake port 31 is a passage formed inside the cylinder head 3 such that one end opens on one side (left side in the figure) of the cylinder head 3 and the other end opens on the top wall of the combustion chamber 26. . One end of the intake port 31 is connected to an intake passage 41 of the intake device 4, and air is supplied to the combustion chamber 26 via the intake port 31.

  The exhaust port 32 is a passage formed inside the cylinder head 3 so that one end opens on the other side (right side in the figure) of the cylinder head 3 and the other end opens on the top wall of the combustion chamber 26. . One end of the exhaust port 32 is connected to an exhaust passage 51 of the exhaust device 5, and combustion gas generated in the combustion chamber 26 is discharged to the exhaust passage 51 via the exhaust port 32.

  The intake valve 33 opens and closes the open end of the intake port 31 on the combustion chamber side.

  The exhaust valve 34 opens and closes the opening end of the exhaust port 32 on the combustion chamber side.

  The intake valve variable valve operating device 35 opens and closes the intake valve 33 and adjusts the opening and closing timing of the intake valve 33 to an arbitrary timing.

  The exhaust valve variable valve device 36 opens and closes the exhaust valve 34 and adjusts the opening and closing timing of the exhaust valve 34 to an arbitrary timing.

  The spark plug 37 is provided so as to face the center of the top wall of the combustion chamber 26. The spark plug 37 generates a spark at an arbitrary time and ignites the air-fuel mixture in the combustion chamber.

  The fuel injection valve 38 directly injects fuel into the combustion chamber 26 at an arbitrary time.

  The intake device 4 includes an intake passage 41 through which air (intake) taken into the engine 1 flows. In the intake passage 41, a supercharger 42, an intercooler 43, a throttle valve 44, and an intake collector 45 are provided in this order from upstream.

  The supercharger 42 is a supercharger that is driven by the crankshaft 25 via a crank pulley and a belt formed at one end of the crankshaft 25. The supercharger 42 forcibly compresses the intake air by using the rotational force of the crankshaft 25 and supplies the compressed intake air to the cylinder 21.

  The intercooler 43 cools intake air that passes through the intercooler 43.

  The throttle valve 44 adjusts the amount of intake air drawn into the intake collector 45 and thus the cylinder 21 by changing the passage step area of the intake passage 41 continuously or stepwise. The throttle valve 44 is opened and closed by a throttle actuator 441, and its opening (hereinafter referred to as “throttle opening”) is detected by a throttle sensor 442. The throttle valve 44 is provided immediately upstream of the intake collector 45 so that the space volume of the intake passage 41 from the throttle valve 44 to the intake collector 45 is as small as possible. The reason for this will be described later with reference to FIG.

  The intake collector 45 evenly distributes the incoming intake air to each cylinder 21.

  The intake passage 41 is further provided with a first bypass passage 46 that bypasses the supercharger 42 and a second bypass passage 47 that bypasses the intercooler 43.

  The first bypass passage 46 is a passage for bypassing the supercharger 42 as necessary so that outside air can be supplied to each cylinder 21 as natural intake air, for example, during non-supercharging. One end of the first bypass passage 46 is connected to the intake passage 41 upstream of the supercharger 42, and the other end is connected to the intake passage 41 between the supercharger 42 and the intercooler 43.

  A first bypass valve 461 is provided in the first bypass passage 46.

  The first bypass valve 461 is opened and closed by an actuator (not shown) to open and close the first bypass passage 46.

  The second bypass passage 47 is a passage for allowing the intake air compressed by the supercharger 42 and having a high temperature during HCCI combustion to be directly supplied to each cylinder 21 by bypassing the intercooler 43. The second bypass passage 47 has one end connected to the first bypass passage 46 on the downstream side of the first bypass valve 461 and the other end connected to the intake collector 45. Of the intake passage 41, the portion to be bypassed to the second bypass passage 47 corresponds to a section from the branch / junction portion of the bypass passage between the supercharger 42 and the intercooler 43 to the intake collector 45. 44 is provided at the most downstream position of the intake passage 41 of the bypassed portion, that is, immediately upstream of the intake collector 45, and is configured so that the space volume of the intake passage 41 from the throttle valve 44 to the intake collector 45 is as small as possible. ing.

  The second bypass passage 47 is provided with a second bypass valve 471 and an intake reformer 472 in order from the upstream.

  The second bypass valve 471 is opened and closed by an actuator (not shown) to open and close the second bypass passage 47. The second bypass valve 471 may be provided at least upstream of the intake reformer 472. In this embodiment, the space volume in the second bypass passage from the second bypass valve 471 to the intake reformer 472 is used. Is provided immediately upstream of the intake reformer 472 so as to be as small as possible. The reason for this will be described later with reference to FIG.

  The intake reformer 472 is provided immediately upstream of the intake collector 45 so that the space volume from the intake reformer 472 to the intake collector 45 is as small as possible. The reason for this will be described later with reference to FIG. The intake reformer 472 generates non-equilibrium plasma and reforms part of oxygen in the intake air to radicals such as ozone. When radicals are present in the gas mixture finally generated in the combustion chamber, the low-temperature oxidation reaction of the gas mixture is promoted from a lower temperature than when it is not present, and various intermediate products In the end, the ignitability of the air-fuel mixture is improved. In this embodiment, non-equilibrium plasma is generated by interposing a dielectric between the discharge electrode and the ground electrode and applying a high frequency high voltage to the discharge electrode. In addition, as long as it is the specification of the electrode and power supply which can form non-equilibrium plasma, not only this form but another form may be sufficient. For example, non-equilibrium plasma may be generated using a microwave or the like.

  The exhaust device 5 includes an exhaust passage 51 through which combustion gas exhausted from the engine 1 (hereinafter referred to as “exhaust”) flows. The exhaust passage 51 is provided with a three-way catalyst 52 that removes harmful substances such as hydrocarbons and nitrogen oxides in the exhaust.

  The controller 6 is composed of a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 6 includes an accelerator stroke sensor 61 that detects an accelerator pedal depression amount (hereinafter referred to as an “accelerator operation amount”) as an engine load and an engine rotation speed sensor 62 that detects an engine rotation speed based on a crank angle. Detection signals from various sensors that detect the operating state of the engine 1 are input.

  The controller 6 switches the combustion method to either HCCI combustion or SI combustion with reference to the operation mode switching map stored in advance based on the detected operating state of the engine 1 and performs supercharging by the supercharger 42. It is determined whether or not to perform.

  FIG. 2 is an operation mode switching map.

  As shown in FIG. 2, the controller 6 switches the operation mode to the supercharged HCCI combustion mode in a predetermined operation region of low rotation and low load. In the supercharged HCCI combustion mode, the controller 6 performs HCCI combustion while performing supercharging by the supercharger 42.

  Further, the operation mode is switched to the supercharging SI combustion mode in a predetermined operation region with a high load. In the supercharging SI combustion mode, the controller 6 performs SI combustion while performing supercharging by the supercharger 42.

  Further, the operation mode is switched to the natural intake SI combustion mode in a predetermined operation region of medium to high rotation and low to medium load. In the natural intake SI combustion mode, the controller 6 performs SI combustion without performing supercharging by the supercharger 42.

  FIG. 3 is a flowchart for explaining the operation mode switching control performed by the controller 6. The controller 6 executes this routine at a predetermined calculation cycle (for example, 10 [ms]) while the engine 1 is operating.

  In step S1, the controller 6 reads the engine speed and the accelerator operation amount as the engine load.

  In step S2, the controller 6 refers to the operation mode switching map of FIG. 2 and determines the current operation region based on the engine speed and the accelerator operation amount. The controller 6 performs the process of step S3 if the current operation region is within the predetermined operation region of low rotation / low load, and step S6 if it is within the predetermined operation region of medium to high rotation / low to medium load. If it is within a predetermined operating region with a high load, the process of step S9 is performed.

  Steps S3 to S5 are processes executed in the supercharging HCCI combustion mode.

  In step S3, the controller 6 closes the first bypass valve 461, opens the second bypass valve 471, and fully closes the throttle valve 44.

  In step S4, the controller 6 drives the supercharger 42.

  In step S5, the controller 6 applies high-frequency high voltage to the discharge electrode of the intake reformer 472 to generate non-equilibrium plasma, and reforms a part of the intake air to radicals.

  Steps S6 to S8 are processes executed in the natural intake SI combustion mode.

  In step S6, the controller 6 opens the first bypass valve 461 and closes the second bypass valve 471. The throttle opening is adjusted according to the accelerator operation amount.

  In step S7, the controller 6 does not drive the supercharger 42.

  In step S <b> 8, the controller 6 stops applying voltage to the discharge electrode of the intake reformer 472.

  Steps S9 to S11 are processes executed in the supercharging SI combustion mode.

  In step S9, the controller 6 closes both the first bypass valve 461 and the second bypass valve 471, and fully opens the throttle valve 44.

  In step S10, the controller 6 drives the supercharger 42.

  In step S <b> 11, the controller 6 stops applying voltage to the discharge electrode of the intake reformer 472.

  FIG. 4 is a diagram simply showing the flow of intake air in each operation mode. FIG. 4A is a diagram showing the flow of intake air in the supercharging SI combustion mode. FIG. 4B is a diagram showing the flow of intake air in the natural intake SI combustion mode. FIG. 4C is a diagram showing the flow of intake air in the supercharged HCCI combustion mode.

  As shown in FIG. 4A, in the supercharged SI combustion mode, the supercharger 42 is driven with the first bypass valve 461 closed. Therefore, the intake air drawn from the intake passage inlet flows through the intake passage 41 without flowing into the first bypass passage 46 and is compressed by the supercharger 42.

  In the supercharging SI combustion mode, the second bypass valve 471 is closed and the throttle valve 44 is fully opened. Therefore, the intake air compressed by the supercharger 42 does not flow into the second bypass passage 47 but flows through the intake passage 41 as it is, and is cooled by the intercooler 43. The intake air cooled by the intercooler 43 flows into the intake collector 45 as it is, and is sucked into each cylinder 21 evenly.

  As shown in FIG. 4B, in the natural intake SI combustion mode, the first bypass valve 461 is opened with the supercharger 42 stopped. Therefore, the intake air drawn from the intake passage inlet flows into the first bypass passage 46.

  In the natural intake SI combustion mode, the second bypass valve 471 is closed and the throttle opening is adjusted according to the operating state. Therefore, the intake air flowing into the first bypass passage 46 does not flow into the second bypass passage 47 but flows into the intake passage 41 downstream of the supercharger 42 and is cooled by the intercooler 43. The intake air cooled by the intercooler 43 is adjusted in flow rate by the throttle valve 44, flows into the intake collector 45, and is equally sucked into each cylinder 21.

  As shown in FIG. 4C, in the supercharged HCCI combustion mode, the supercharger 42 is driven with the first bypass valve 461 closed. Therefore, the intake air drawn from the intake passage inlet flows through the intake passage 41 without flowing into the first bypass passage 46 and is compressed by the supercharger 42.

  In the supercharged HCCI combustion mode, since the second bypass valve 471 is opened with the throttle valve 44 fully closed, the intake air compressed to the high temperature by the supercharger 42 flows into the second bypass passage 47. .

  A part of oxygen in the intake air flowing into the second bypass passage 47 is converted into plasma by the intake air reformer 472 to generate radicals. At this time, in this embodiment, since the intake reformer 472 is provided immediately upstream of the intake collector 45, the generated radicals can be supplied to the intake collector 45 while maintaining a high active state, and evenly supplied to each cylinder 21. Can be supplied.

  In the present embodiment, the throttle valve 44 is provided immediately upstream of the intake collector 45 so that the space volume of the intake passage 41 from the throttle valve 44 to the intake collector 45 is as small as possible. Therefore, it is possible to reduce the proportion of the intake air flowing into the intake air collector 45 that flows back to the intake passage 41 side.

  As a result, the amount of the intake air that flows into the intake collector 45 and flows back into the intake passage 41 and remains in the intake passage 41 between the throttle valve 44 and the intake collector 45 can be reduced. Therefore, the intake air flowing into the intake collector 45 can be supplied to each cylinder 21 without waste. That is, radicals generated by the intake reformer 472 and supplied to the intake collector 45 can be efficiently supplied to each cylinder 21.

  Next, the reason why the second bypass valve 471 is provided immediately upstream of the intake reformer 472 will be described.

  As shown in FIGS. 4A and 4B, in the supercharging SI combustion mode and the natural intake SI combustion mode, the intake air cooled by the intercooler 43 and having a relatively low temperature is discharged from the intake passage 41. It is supplied to the intake collector 45.

  On the other hand, as shown in FIG. 4C, in the supercharged HCCI combustion mode diagram, the intake air that has been supercharged by the supercharger 42 and has a relatively high temperature is supplied from the second bypass passage 47 to the intake collector 45. The

  Here, it is assumed that part of the low-temperature intake air supplied to the intake collector 45 flows back to the second bypass passage 47 side during the supercharging SI combustion mode and the natural intake SI combustion mode. When the low-temperature intake air that has flowed back to the second bypass passage 47 remains in the vicinity of the intake reformer 472, the intake air that has been supercharged by the supercharger 42 into the second bypass passage 47 and that has become relatively hot flows. The change in the ambient temperature in the second bypass passage 47 becomes large.

  As a result, the temperature of the discharge electrode and the ground electrode of the intake reformer 472 changes suddenly, and what is reformed by the intake reformer 472 may change, making it impossible to generate adequate radicals sufficiently.

  Therefore, in this embodiment, the second bypass valve 471 is provided immediately upstream of the intake reformer 472, and the space volume in the second bypass passage 47 from the second bypass valve 471 to the intake reformer 472 is as small as possible. It was made to become. Thereby, in the supercharged SI combustion mode and the natural intake SI combustion mode, it is possible to suppress the flow rate of the low-temperature intake air that flows backward from the intake collector 45 toward the second bypass passage 47, and the low-temperature intake air is in the vicinity of the intake reformer 472. Can be suppressed.

  Therefore, since the change in the atmospheric temperature in the second bypass passage 47 can be reduced, the change in the temperature of the discharge electrode and the ground electrode of the intake reformer 472 can be suppressed, and appropriate radicals are generated by the intake reformer 472. it can.

  In order to suppress the temperature change in the vicinity of the intake reformer 472, it may be better to install the second bypass valve 471 downstream of the intake reformer 472, but for the following reason Not appropriate. That is, if the second bypass valve 471 is installed downstream of the intake reformer 472, various parts of the second bypass valve 471, such as seal parts, are oxidized and deteriorated by radicals generated by the intake reformer 472. As a result, radicals may be released from the second bypass passage 47 to the outside air.

  According to the present embodiment described above, in the supercharging SI combustion mode and the natural intake SI combustion mode, the intake air that has passed through the intercooler 43 is supplied to the intake collector 45 and is equally sucked into each cylinder 21. did. On the other hand, in the supercharged HCCI combustion mode, the intake air is supplied to the intake collector 45 from the second bypass passage 47 provided with the intake reformer 472 without passing through the intercooler 43, and is uniformly sucked into each cylinder 21. It was.

  Thus, radicals selectively generated by the intake reformer 472 can be included in the intake air during the supercharged HCCI combustion mode, and the ignitability of the air-fuel mixture during the supercharged HCCI combustion mode can be improved. . Further, it is possible to prevent the intake reformer 472 from becoming a ventilation resistance during the supercharging SI combustion mode and the natural intake SI combustion mode.

  Further, since a part of oxygen in the intake air flowing through the second bypass passage 47 is converted into plasma by the intake reformer 472 to generate radicals, an air introduction passage for supplying air to the intake reformer 472 separately, There is no need to provide a pump. Therefore, it is possible to prevent the intake device 4 from becoming complicated.

  Furthermore, since the intake air containing radicals is supplied to the intake collector 45, it is not necessary to provide the intake reformer 472 for each cylinder 21, and the cost can be reduced.

  Further, according to the present embodiment, the intake reformer 472 is disposed in the second bypass passage 47 immediately upstream of the intake collector 45 so that the space volume from the intake reformer 472 to the intake collector 45 is as small as possible. Provided.

  As a result, radicals generated by the intake reformer 472 can be supplied to the intake collector 45 while maintaining a high active state, and can be evenly supplied to each cylinder 21.

  Further, according to the present embodiment, the throttle valve 44 is provided in the intake passage 41 immediately upstream of the intake collector 45 so that the space volume from the throttle valve 44 to the intake collector 45 is as small as possible. In this way, by reducing the space volume from the throttle valve 44 to the intake collector 45, of the intake air containing radicals that flow into the intake collector 45 in the supercharged HCCI combustion mode, The ratio can be reduced.

  Thereby, it is possible to suppress the intake air supplied to the intake collector 45 from stagnation in the intake passage 41 between the throttle valve 44 and the intake collector 45. Therefore, the radical generated by the intake reformer 472 and supplied to the intake collector 45 can be efficiently supplied from the intake collector 45 to each cylinder 21 without waste.

  Further, according to the present embodiment, the second bypass valve 471 is provided immediately upstream of the intake reformer 472 so that the space volume from the second bypass valve 471 to the intake reformer 472 is as small as possible. .

  Thereby, in the supercharging SI combustion mode and the natural intake SI combustion mode, it is possible to suppress the flow rate of the low-temperature intake air that flows backward from the intake collector 45 toward the second bypass passage 47, and the low-temperature intake air is in the vicinity of the intake reformer 472. Can be suppressed.

  Therefore, since the change in the atmospheric temperature in the second bypass passage 47 can be reduced, the change in the temperature of the discharge electrode and the ground electrode of the intake reformer 472 can be suppressed, and appropriate radicals are generated by the intake reformer 472. it can.

  In addition, by providing the second bypass valve 471 upstream of the intake reformer 472, various parts, such as seal parts, that constitute the second bypass valve 471 are oxidized and deteriorated by radicals generated by the intake reformer 472. Can be suppressed, and radicals can be prevented from being released from the second bypass passage 47 to the outside air.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment of the present invention is different from the first embodiment in that the first bypass passage 46 is not provided. Hereinafter, the difference will be mainly described. In each embodiment described below, the same reference numerals are used for portions that perform the same functions as those of the above-described embodiments, and repeated description is appropriately omitted.

  FIG. 5 is a schematic configuration diagram of the engine 1 according to the second embodiment of the present invention.

  The engine 1 according to the present embodiment is provided with a throttle valve 44 in the intake passage 41 upstream of the supercharger 42. Then, a separate on-off valve 48 for opening and closing the intake passage 41 is provided in the intake passage 41 immediately upstream of the intake collector 45 where the throttle valve 44 is disposed in the first embodiment. The on-off valve 48 is driven to open and close by an actuator (not shown).

  FIG. 6 is a flowchart for explaining the operation mode switching control according to the present embodiment. The controller 6 executes this routine at a predetermined calculation cycle (for example, 10 [ms]) while the engine 1 is operating.

  In step S23, the controller 6 adjusts the throttle opening according to the accelerator operation amount. Then, the on-off valve 48 is fully closed and the second bypass valve 471 is opened.

  In step S26, the controller 6 adjusts the throttle opening according to the accelerator operation amount. Then, the on-off valve 48 is fully opened and the second bypass valve 471 is closed.

  In step S29, the controller 6 adjusts the throttle opening according to the accelerator operation amount. Then, the on-off valve 48 is fully opened and the second bypass valve 471 is closed.

  In the present embodiment described above, the same effect as that of the first embodiment can be obtained, and the intake device 4 can be simplified by the amount of the absence of the first bypass passage 46.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  For example, as shown in FIG. 7, the intercooler 43 may be provided inside the intake collector 45, and the intercooler 43 and the intake collector 45 may be integrated.

  In each of the above embodiments, the supercharger 42 is used as a supercharger. However, a turbocharger may be used.

  Further, in each of the above embodiments, radicals are generated by reforming a part of oxygen in the intake air by the intake reformer 472, but the intake reformer 472 is installed for the radicals generated in advance. You may make it supply from a location.

1 Internal combustion engine 41 Intake passage 42 Supercharger (supercharger)
43 Intercooler 44 Throttle valve (intake on / off valve)
45 Intake collector 47 Second bypass passage (bypass passage)
471 Second bypass valve (Bypass open / close valve)
472 Intake reformer (active species generator)
48 On-off valve (intake on-off valve)

Claims (4)

A turbocharger provided in the intake passage;
An intake collector provided in an intake passage downstream of the supercharger;
The intake passage between the supercharger and the intake collector, or an intercooler provided in the intake collector;
A bypass passage having one end connected to an intake passage downstream of the supercharger and the other end connected to the intake collector so as to bypass the intercooler;
An active species generator that is provided in the bypass passage immediately upstream of the intake collector and generates active species that improve the ignitability of the air-fuel mixture in the bypass passage;
A bypass on-off valve that is provided in the bypass passage upstream of the active species generator and opens and closes the bypass passage;
An intake on-off valve provided in the intake passage immediately upstream of the intake collector in the bypassed portion bypassed by the bypass passage, and opens and closes the intake passage of the bypassed portion;
An internal combustion engine. The bypass on-off valve is provided immediately upstream of the active species generator.
The internal combustion engine according to claim 1. The bypass on-off valve is closed when supplying the intake air cooled by the intercooler to the intake collector.
The internal combustion engine according to claim 1 or 2, characterized in that. The active species generator generates active species during inspiration by reforming part of the intake air to generate active species,
The internal combustion engine according to any one of claims 1 to 3, wherein the internal combustion engine is characterized by that.

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