JP2010001865A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine capable of enhancing an ignitability improving effect. <P>SOLUTION: The engine supplied with radicals in a combustion chamber is provided with: an intake valve 31 for opening/closing an intake port 30; a valve-timing adjusting device 200 for adjusting valve timing of the intake valve 31; a discharge unit 50 including a first electrode 51, a dielectric element 53 covering the first electrode 51, and a second electrode 52 arranged at a position to face the dielectric element 53, and constituted such that a discharge chamber 55 formed between the second electrode 52 and the dielectric element 53 faces a combustion chamber 13, thereby to generate an unbalanced plasma discharge in the discharge chamber 55; a voltage applying means 60 for applying voltage to the discharge unit 50 so that the radicals can be produced in the discharge chamber by the unbalanced plasma discharge; and a controller 70 for controlling the valve-timing adjusting device 200 so that an intake valve closing period for closing the intake valve 31 can be provided during the downward movement of the piston from an exhaust top dead center to an intake bottom dead center, thereby to diffuse the radicals in the discharge chamber into the combustion chamber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine that supplies radicals into a combustion chamber.

  2. Description of the Related Art Conventionally, a compression ignition engine that compresses and burns an air-fuel mixture by a compression action of a piston is widely known (for example, Patent Document 1).

Patent Document 1 discloses a compression ignition engine in which a discharge part for non-equilibrium plasma discharge is provided so as to face the center of a combustion chamber, and radicals are generated by non-equilibrium plasma discharge in this discharge part. Since this radical is an active chemical species having high reactivity, the ignitability of the air-fuel mixture can be improved.
JP 2007-309160 A

  However, in the engine described in Patent Document 1, since the cylinder head is provided with a recess to form the discharge part, the radicals generated in the discharge part are unlikely to flow out to the combustion chamber side, and the radical and the air-fuel mixture in the combustion chamber are not generated. Hard to mix. Therefore, there is a problem that the effect of improving ignitability by radicals is reduced.

  Therefore, the present invention has been made paying attention to such problems, and an object thereof is to provide an engine capable of enhancing the ignitability improvement effect.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention relates to an intake valve (31) for opening and closing an intake port (30), a valve timing adjusting device (200) for adjusting the valve timing of the intake valve (31), and an engine for supplying radicals into a combustion chamber, A first electrode (51), a dielectric (53) covering the first electrode (51), and a second electrode (52) disposed at a position facing the dielectric (53); 52) and a discharge part (50) configured to cause a discharge chamber (55) formed between the dielectric (53) to face the combustion chamber (13) and generating a non-equilibrium plasma discharge in the discharge chamber; Voltage application means (60) for applying a voltage to the discharge part (50) so that radicals are generated in the discharge chamber by non-equilibrium plasma discharge, and an intake valve (during piston lowering from the exhaust top dead center to the intake bottom dead center) 31) has an intake valve closing period to close So that the by controlling the valve timing control device (200), and control means for diffusing the discharge chamber of the radicals in the combustion chamber (70), characterized in that it comprises a.

  According to the present invention, it is possible to cause radicals in the discharge chamber to flow out to the combustion chamber side by utilizing the decrease in the in-cylinder pressure. Thereby, since radicals diffuse into the air-fuel mixture, it becomes possible to enhance the ignitability improvement effect by radicals.

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

(First embodiment)
FIG. 1 is a schematic configuration diagram of a compression ignition engine 100.

  The compression ignition engine 100 includes a cylinder block 10 and a cylinder head 20 disposed on the upper side of the cylinder block 10.

  The cylinder block 10 is formed with a cylinder 12 that houses the piston 11. A combustion chamber 13 is formed by the crown surface of the piston 11, the wall surface of the cylinder 12, and the lower surface of the cylinder head 20. When the air-fuel mixture burns in the combustion chamber 13, the piston 11 receives a combustion pressure due to combustion and reciprocates the cylinder 12.

  The cylinder head 20 is formed with an intake port 30 through which an air-fuel mixture flows into the combustion chamber 13 and an exhaust port 40 through which exhaust from the combustion chamber 13 flows.

  The intake port 30 is provided with an intake valve 31. The intake valve 31 is driven by the swing cam 210 of the variable valve operating apparatus 200, and opens and closes the intake port 30 according to the vertical movement of the piston 11. The variable valve apparatus 200 changes valve characteristics such as the lift amount and valve timing of the intake valve 31. A fuel injection valve 32 is installed in the intake port 30. The fuel injection valve 32 injects fuel toward the opening of the intake port 30 to the combustion chamber 13 at a predetermined time during the exhaust stroke or the intake stroke.

  The exhaust port 40 is provided with an exhaust valve 41. The exhaust valve 41 is driven by a cam 43 integrally formed with the camshaft 42 and opens and closes the exhaust port 40 according to the vertical movement of the piston 11.

  With reference to FIG.2 and FIG.3, the variable valve apparatus 200 which changes the valve characteristic of the intake valve 31 is demonstrated. FIG. 2 is a schematic configuration diagram of the variable valve apparatus 200. FIG. 3 is a view showing an example of the lift amount and the operating angle of the intake valve 31 driven by the variable valve operating apparatus 200.

  As shown in FIG. 2, the variable valve apparatus 200 includes a swing cam 210, a swing cam drive mechanism 220 that swings the swing cam 210, and a lift that can continuously change the lift amount of the intake valve 31. The variable amount mechanism 230 is provided.

  The swing cam 210 is rotatably fitted on the outer periphery of the drive shaft 221 extending in the cylinder row direction. Since the compression ignition engine 100 includes two intake valves 31 for one cylinder, two swing cams 210 and a valve lifter 211 are provided for one cylinder. The two swing cams 210 are coupled in the same phase state by a connecting cylinder 221A that is rotatably inserted into the drive shaft 221, and operates in synchronism with each other. Therefore, the swing cam drive mechanism 220 is provided for only one swing cam 210.

  An eccentric cam 222 is press-fitted into the drive shaft 221 of the swing cam drive mechanism 220. In the eccentric cam 222 having a circular outer peripheral surface, the center of the outer peripheral surface is offset from the axis of the drive shaft 221 by a predetermined amount. Since the drive shaft 221 rotates in conjunction with the rotation of the crankshaft, the eccentric cam 222 rotates eccentrically around the axis of the drive shaft 221.

  An annular portion 224 on the base end side of the first link 223 is rotatably fitted to the outer periphery of the eccentric cam 222. The distal end of the first link 223 is connected to one end of the rocker arm 226 via a connecting pin 225. The other end of the rocker arm 226 is connected to the upper end of the second link 228 via a connecting pin 227. The lower end of the second link 228 is connected to a swing cam 210 that drives the intake valve 31 via a connecting pin 229. The substantially central portion of the rocker arm 226 is swingably supported by an eccentric cam portion 232 that is press-fitted into the control shaft 231 of the lift amount varying mechanism 230.

  When the drive shaft 221 rotates in synchronization with the engine rotation, the eccentric cam 222 rotates eccentrically, and thereby the first link 223 swings in the vertical direction. The rocker arm 226 swings around the axis of the eccentric cam portion 232 by the swing of the first link 223, the second link 228 swings up and down, and the swing cam 210 rotates about the axis of the drive shaft 221 by a predetermined amount. Oscillate in an angular range. In this way, the swing cam 210 swings the same in synchronism with each other, whereby the intake valve 31 opens and closes the intake port 30.

  In the variable valve apparatus 200, one end of the drive shaft 221 is inserted into the cam sprocket, and the drive shaft 221 is configured to rotate relative to the cam sprocket. Therefore, the drive shaft 221 can change the phase with respect to the cam sprocket, and the rotation phase of the drive shaft 221 with respect to the crankshaft can be changed.

  In addition, an actuator is provided at one end of the control shaft 231 of the variable lift amount mechanism 230 via a gear or the like. By changing the rotational position of the control shaft 231 by this actuator, the shaft center of the eccentric cam portion 232 that becomes the rocking center of the rocker arm 226 turns around the rotational center of the control shaft 231, and accordingly, the fulcrum of the rocker arm 226 becomes a fulcrum. Displace. As a result, the postures of the first link 223 and the second link 228 change, the distance between the swing center of the swing cam 210 and the rotation center of the rocker arm 226 changes, and the swing characteristics of the swing cam 210 change. To do.

  In the variable valve apparatus 200 described above, by changing the angle of the control shaft 231 and the phase of the drive shaft 221 with respect to the cam sprocket, the valve characteristics such as the lift amount and operating angle of the intake valve 31 are continuously changed as shown in FIG. Can be changed.

  On the other hand, between the intake port 30 and the exhaust port 40 and at the center of the cylinder head 20, a discharge unit 50 for generating radicals is installed as shown in FIG. The discharge part 50 includes a center electrode 51, a cylindrical electrode 52, an insulating part 53, and a metal shell 54.

  The discharge part 50 is installed in the cylinder head 20 by a metal shell 54 provided at the center in the axial direction of the insulating part 53.

  The center electrode 51 is made of a rod-shaped conductor and extends so that the tip protrudes from the metal shell 54 toward the discharge chamber 55. The center electrode 51 is covered with an insulating part 53 made of a dielectric. A rear end side terminal 51 </ b> A is provided at the rear end of the center electrode 51.

  The cylindrical electrode 52 is a cylindrical conductor and is provided so as to surround the insulating portion 53 and face the center electrode 51. The cylindrical electrode 52 is grounded via the cylinder head 20. A discharge chamber 55 that faces the combustion chamber 13 is formed between the insulating portion 53 and the cylindrical electrode 52.

  The discharge unit 50 is connected to the high-voltage and high-frequency generator 60 via the rear end side terminal 51A of the center electrode 51. The high voltage high frequency generator 60 applies an AC voltage to the rear end side terminal 51A according to the engine operating state.

  When an AC voltage is applied from the high voltage high frequency generator 60 to the rear end side terminal 51 </ b> A, non-equilibrium plasma discharge occurs between the insulating part 53 of the discharge part 50 and the cylindrical electrode 52, and radicals are generated inside the discharge chamber 55. Generated. The amount of radicals generated increases as the discharge energy of non-equilibrium plasma discharge increases. The discharge energy of the non-equilibrium plasma discharge is controlled by the voltage value of the AC voltage applied by the high-voltage high-frequency generator 60, the application time, and the AC frequency.

  The compression ignition engine 100 includes a controller 70 for controlling the high voltage high frequency generator 60 and the variable valve operating apparatus 200. The controller 70 has a CPU, a ROM, a RAM, and an I / O interface. The controller 70 receives outputs from various sensors that detect engine operating conditions such as engine speed and engine load. Based on these outputs, the controller 70 controls the voltage value, application time, and AC frequency of the AC voltage from the high-voltage and high-frequency generator 60, or controls the variable valve device 200 to change the valve characteristics of the intake valve 31. To do.

  In the compression ignition engine 100 described above, radicals are generated in order to improve the ignitability during compression ignition combustion. However, since radicals are generated in the discharge chamber, the radicals and the air-fuel mixture in the combustion chamber are difficult to mix. Therefore, the effect of improving the ignitability by radicals is reduced. Therefore, in the compression ignition engine 100, ignition is performed by adjusting the valve characteristics of the intake valve 31 and the radical generation timing in the discharge unit 50 and controlling the radicals to diffuse into the mixture (radical diffusion control). Increases the effect of improving sexiness.

  This radical diffusion control will be described with reference to FIGS.

  FIG. 4 is an operation map represented by engine speed and load. The compression ignition engine 100 is operated based on the operation map shown in FIG.

  When the engine operating state is in the region B on the high rotation speed side or the high load side, the ignitability at the time of compression ignition combustion does not matter so much, so normal control is performed without performing radical diffusion control. In this normal control, the intake valve 31 is controlled so that it opens at IVO before exhaust top dead center and closes at IVC after intake bottom dead center, and radicals are released at a predetermined time during the exhaust stroke or intake stroke. The discharge unit 50 is controlled so as to be generated.

  On the other hand, when the engine operating state is in the low rotation speed / low load region A, radical diffusion control is performed. The reason for controlling in this way is that, at a low rotational speed and low load range, the temperature of the air-fuel mixture compressed in the compression stroke is lowered and the ignitability is deteriorated. In this radical diffusion control, the IVC of the intake valve 31 is advanced and controlled before the intake bottom dead center, and the radical generation timing in the discharge unit 50 is controlled before the IVC.

  FIG. 5 is a timing chart showing the action of radical diffusion control.

  As shown in FIG. 5B, the exhaust in the combustion chamber is discharged in the exhaust stroke in which the piston 11 rises to the exhaust top dead center. Then, as shown in FIG. 5A, non-equilibrium plasma discharge is performed in the discharge section 50 until the piston 11 reaches the exhaust top dead center in the latter half of the exhaust stroke. Therefore, the amount of radicals in the discharge chamber increases until exhaust top dead center.

  The intake valve 31 is controlled to open before exhaust top dead center and close before intake bottom dead center. When the intake valve 31 is opened before the exhaust top dead center, the air-fuel mixture formed in the intake port is introduced into the combustion chamber 13 as shown in FIG. The intake valve 31 closes before the intake bottom dead center, but the piston 11 descends even after the intake valve closes, so the pressure in the combustion chamber (cylinder pressure) decreases. When the in-cylinder pressure is thus reduced, the radicals in the discharge chamber 55 flow out to the combustion chamber side as shown in FIG. 5D, and the radicals diffuse into the air-fuel mixture in the combustion chamber 13.

  When the piston 11 passes the intake bottom dead center and starts to rise toward the compression top dead center, the air-fuel mixture containing radicals flows into the discharge chamber as shown in FIG. Therefore, as shown in FIG. 5A, the air-fuel mixture amount in the discharge chamber increases after a while after the intake bottom dead center. When the piston 11 reaches the vicinity of the compression top dead center, the air-fuel mixture in the discharge chamber and the combustion chamber is subjected to compression ignition combustion.

  As described above, the compression ignition engine 100 can obtain the following effects.

  In the compression ignition engine 100, the IVC of the intake valve 31 is controlled to advance before the intake bottom dead center, and radicals are generated in the discharge unit 50 before the IVC. Therefore, the reduction in the in-cylinder pressure is utilized. Radicals in the discharge chamber can flow out to the combustion chamber side. Thereby, since radicals diffuse into the air-fuel mixture, it becomes possible to enhance the ignitability improvement effect by radicals.

  In the compression ignition engine 100, since the radical diffusion control is executed in a low rotation speed and low load range where the ignitability is likely to deteriorate, the compression ignition combustion can be stably performed regardless of the engine operating state.

(Second Embodiment)
The configuration of the compression ignition engine 100 of the second embodiment is substantially the same as that of the first embodiment, but is partly different in the engine operation on the low load side than the region A. That is, the second radical diffusion control is performed when the engine operating state is on the low load side, and the difference will be mainly described below.

  FIG. 6 is an operation map represented by engine speed and load. The compression ignition engine 100 is operated based on the operation map shown in FIG.

  In the compression ignition engine 100, radical diffusion control (first radical diffusion control) is performed in the region A of low rotation speed and low load, and second radical diffusion control is performed in the region C on the lower load side than the region A. In this second radical diffusion control, the variable valve apparatus 200 controls the IVO of the intake valve 31 to be retarded after the exhaust top dead center, and the IVC is advanced to be controlled before the intake bottom dead center. Then, the high-voltage high-frequency generator 60 generates radicals by performing non-equilibrium plasma discharge at the discharge unit 50 before IVO and after IVO and before IVC.

The operation of the second radical diffusion control will be described with reference to FIG. 7. In the compression ignition engine 100, as shown in FIG. 7A, the discharge unit 50 performs the first time in the latter half of the exhaust stroke before exhaust top dead center. The non-equilibrium plasma discharge is performed to increase the amount of radicals in the discharge chamber.

  The intake valve 31 opens after exhaust top dead center. Since the piston 11 is lowered before the intake valve is opened, the in-cylinder pressure is lowered, and radicals generated in the discharge chamber 55 flow out to the combustion chamber side as shown in FIG. 7B. When the intake valve 31 opens after exhaust top dead center, the air-fuel mixture formed in the intake port is introduced into the combustion chamber 13 as shown in FIG. At this time, the air-fuel mixture flowing into the combustion chamber from the intake port is mixed with the radicals flowing out into the combustion chamber. Further, since the in-cylinder pressure is reduced as described above, a part of the air-fuel mixture flows into the discharge chamber 55 of the discharge unit 50 when the air-fuel mixture is introduced into the combustion chamber. Therefore, as shown in FIG. 7A, after a while after the intake valve is opened, the air-fuel mixture amount in the discharge chamber increases.

  Then, after the intake valve is opened and before the intake valve 31 is closed, the discharge unit 50 performs the second non-equilibrium plasma discharge. During the second non-equilibrium plasma discharge, since the air-fuel mixture exists in the discharge chamber, the radical generation efficiency is higher than that during the first non-equilibrium plasma discharge.

  The intake valve 31 closes before the intake bottom dead center, but even after the intake valve closes, the piston 11 descends until the piston 11 reaches the intake bottom dead center, so the in-cylinder pressure decreases. When the in-cylinder pressure is thus reduced, the radicals generated in the discharge chamber 55 again flow out to the combustion chamber side as shown in FIG. 7D, and the radicals diffuse into the air-fuel mixture in the combustion chamber 13.

  When the piston 11 starts to rise toward the compression top dead center, an air-fuel mixture containing radicals flows into the discharge chamber as shown in FIG. When the piston 11 reaches the vicinity of the compression top dead center, the air-fuel mixture in the discharge chamber and the combustion chamber is subjected to compression ignition combustion.

  As described above, the compression ignition engine 100 can obtain the following effects.

In the compression ignition engine 100, in the region C on the low load side, the IVO of the intake valve 31 is retarded after the exhaust top dead center and the IVC is advanced before the intake bottom dead center. Then, the first non-equilibrium plasma discharge is performed before the IVO, and the second non-equilibrium plasma discharge is performed after the IVO and before the IVC to generate radicals in the discharge chamber of the discharge unit 50. .
For this reason, the number of times the radicals in the discharge chamber are allowed to flow out to the combustion chamber side can be increased, and the radicals can be more easily diffused into the air-fuel mixture than in the first embodiment, thereby further improving the effect of improving the ignitability by the radicals. As a result, even in the region C on the low load side where the ignitability of the air-fuel mixture deteriorates, it is possible to stably perform compression ignition combustion.

(Third embodiment)
FIG. 8 is a schematic configuration diagram of the compression ignition engine 100 of the third embodiment.

  The configuration of the compression ignition engine 100 of the third embodiment is substantially the same as that of the second embodiment, but is partially different at the installation position of the fuel injection valve 32. That is, the fuel injection valve 32 is arranged so as to inject fuel directly into the combustion chamber, and the difference will be mainly described below.

  As shown in FIG. 8, the fuel injection valve 32 is disposed in the cylinder head 20 so as to inject fuel directly into the combustion chamber. The fuel injection valve 32 injects fuel before the intake valve 31 is opened. The fuel injection valve 32 is configured such that part of the injected fuel is directed to the opening end 52 </ b> A of the cylindrical electrode 52 of the discharge unit 50.

  In the compression ignition engine 100 as described above, when the engine operating state is in the region C, the following effects can be obtained.

  Before the second non-equilibrium plasma discharge in the second radical diffusion control is performed, the fuel is directly blown into the discharge chamber 55 of the discharge unit 50, so that the air-fuel mixture flows into the discharge chamber as in the second embodiment. The radical generation efficiency can be increased as compared with the case of doing so. Thereby, it is possible to suppress the input energy to the discharge unit 50.

(Fourth embodiment)
FIG. 9 is a schematic configuration diagram of the compression ignition engine 100 of the fourth embodiment. FIG. 9A is a diagram showing the discharge unit 50, and FIG. 9B is a diagram when FIG. 9A is viewed from the B direction.

  The configuration of the compression ignition engine 100 of the fourth embodiment is substantially the same as that of the first embodiment, but a part of the configuration of the discharge unit 50 is different. That is, the discharge chamber 55 and the combustion chamber 13 of the discharge unit 50 are communicated with each other by the communication passage 52B formed in the cylindrical electrode 52, and the difference will be mainly described below.

  The cylindrical electrode 52 of the discharge part 50 is comprised so that the insulating part 53 which covers the center electrode 51 may be surrounded, as shown to FIG. 9 (A). Therefore, the space formed between the insulating portion 53 and the cylindrical electrode 52 becomes the discharge chamber 55. The cylindrical electrode 52 is provided with a plurality of small-diameter communication passages 52B at the tip, and the discharge chamber 55 and the combustion chamber 13 communicate with each other through the communication passage 52B. These communication paths 52B are arranged at equal intervals in the circumferential direction of the tip side surface of the cylindrical electrode 52, as shown in FIG.

  In the compression ignition engine 100 configured as described above, radicals in the discharge chamber are caused to flow out to the combustion chamber side by utilizing the decrease in the in-cylinder pressure generated by the piston descending after the intake valve is closed. The outflow rate of radicals is increased when the radicals flow out to the combustion chamber 13 through the communication path 52B. Further, radicals are ejected radially into the combustion chamber as shown in FIG.

  As described above, the compression ignition engine 100 can obtain the following effects.

  In the compression ignition engine 100, since the accelerated radicals are ejected radially into the combustion chamber, the radicals are more easily diffused into the air-fuel mixture than in the first embodiment, and the ignitability improvement effect by the radicals can be further enhanced. It becomes.

(Fifth embodiment)
FIG. 10 is a schematic configuration diagram of a compression ignition engine 100 of the fifth embodiment.

  The configuration of the compression ignition engine 100 of the fifth embodiment is substantially the same as that of the fourth embodiment, but is partially different from the region A in engine operation on the low load side. That is, the air-fuel mixture is stratified when the engine operating state is on the low load side, and the difference will be mainly described below.

  As shown in FIG. 10, the piston 11 has a recess 11 </ b> A formed so that a part of the piston crown surface is recessed.

  And the communication path 52B of the cylindrical electrode 52 of the discharge part 50 is arrange | positioned so that the radical spouted from the communication path 52B may face the recessed part 11A of the piston 11. FIG.

  The fuel injection valve 32 is disposed in the cylinder head 20 so as to inject fuel directly into the combustion chamber. The fuel injection valve 32 is configured such that the injected fuel is directed to the recess 11 </ b> A of the piston 11.

  As shown in FIG. 11A, the compression ignition engine 100 configured as described above drives the fuel injection valve 32 during the compression stroke in the region C on the lower load side than the region A to generate the air-fuel mixture. Plan stratification. In the region C, radical diffusion control similar to that in the region A is performed.

  The stratified operation of the compression ignition engine 100 when the engine operating state is in the region C will be described with reference to FIGS. 11 (B) and 11 (C).

  In the compression ignition engine 100, since radical diffusion control is also performed in the region C, during the period from when the intake valve is closed until the piston 11 is lowered to the intake bottom dead center, as shown in FIG. The radicals formed in are ejected to the combustion chamber side through the communication passage 52B. This radical is ejected toward the recess 11A of the piston 11 as shown in the region R of FIG.

  Then, during the compression stroke in which the piston 11 rises toward the compression top dead center, the fuel is directly injected from the fuel injection valve 32 into the combustion chamber. This fuel is injected toward the concave portion 11A of the piston 11 as shown in a region F of FIG. At this time, since the radicals stay in the concave portion 11A of the piston 11 as shown in the region R of FIG. 11C, the radical and the fuel are mixed in the concave portion 11A to form an air-fuel mixture. Thereafter, when the piston 11 reaches the vicinity of the compression top dead center, the air-fuel mixture undergoes compression ignition combustion.

  As described above, the compression ignition engine 100 can obtain the following effects.

  In the compression ignition engine 100, radicals are retained in the recess 11A of the piston 11 in the region C on the low load side, and fuel is injected toward the recess 11A during the compression stroke. Therefore, even if the stratified operation is performed in the region C on the low load side, the ignitability can be improved efficiently. In addition, this stratified operation can improve fuel efficiency.

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

  In the first embodiment, the IVC of the intake valve 11 is set before the intake bottom dead center, thereby reducing the in-cylinder pressure and allowing radicals to flow out from the discharge chamber 55 of the discharge unit 50 to the combustion chamber side. However, it is not limited to this. That is, the valve timing of the intake valve 31 is controlled by the electromagnetic actuator, and a period during which the intake valve 31 closes (intake valve closed period) is provided before the piston 11 descends from the exhaust top dead center to the intake bottom dead center. You may comprise as follows. Since the in-cylinder pressure decreases during the intake valve closing period, radicals can flow out from the discharge chamber 55 to the combustion chamber side, and the radicals can be diffused into the air-fuel mixture.

It is a schematic block diagram of the compression ignition engine of 1st Embodiment. It is a schematic block diagram of a variable valve apparatus. It is a figure which shows an example of the lift amount and operating angle of an intake valve. 3 is an operation map represented by engine rotation speed and load. It is a timing chart which shows the effect | action of radical diffusion control. It is a driving | operation map of the compression ignition engine of 2nd Embodiment. It is a timing chart which shows the effect | action of 2nd radical diffusion control. It is a schematic block diagram of the compression ignition engine of 3rd Embodiment. It is a schematic block diagram of the compression ignition engine of 4th Embodiment. It is a schematic block diagram of the compression ignition engine of 5th Embodiment. It is a figure which shows the stratification operation | movement of a compression ignition engine.

Explanation of symbols

100 Compression ignition engine 200 Variable valve gear (valve timing adjusting device)
DESCRIPTION OF SYMBOLS 10 Cylinder block 11 Piston 11A Recessed part 12 Cylinder 13 Combustion chamber 20 Cylinder head 30 Intake port 31 Intake valve 32 Fuel injection valve (fuel supply means)
50 Discharge part 51 Center electrode (first electrode)
52 Cylindrical electrode (second electrode)
52B Communication path 53 Insulation part (insulator)
55 Discharge chamber 60 High voltage high frequency generator (voltage application means)
70 Controller (control device)

Claims (11)

In an engine that supplies radicals into the combustion chamber,
An intake valve that opens and closes the intake port;
A valve timing adjusting device for adjusting the valve timing of the intake valve;
A discharge chamber formed between the second electrode and the dielectric, the first electrode; a dielectric covering the first electrode; and a second electrode disposed at a position facing the dielectric. A discharge section configured to face the combustion chamber and generate a non-equilibrium plasma discharge in the discharge chamber;
Voltage applying means for applying a voltage to the discharge part so that radicals are generated in the discharge chamber by non-equilibrium plasma discharge;
The valve timing control device is controlled so as to have an intake valve closing period in which the intake valve is closed while the piston descends from the exhaust top dead center to the intake bottom dead center, and the radicals in the discharge chamber are diffused into the combustion chamber. Control means for causing
An engine comprising: The control means controls the voltage application means so that a non-equilibrium plasma discharge is generated from exhaust top dead center until the intake valve closing period ends.
The engine according to claim 1. The control means controls the valve timing adjusting device so that the closing timing of the intake valve is before the intake bottom dead center, and sets the intake valve closing period;
The engine according to claim 1 or 2, characterized by the above. The control means controls the valve timing adjusting device so that the opening timing of the intake valve is after exhaust top dead center, and sets the intake valve closing period;
The engine according to claim 1 or 2, characterized by the above. The control means controls the opening timing of the intake valve after the exhaust top dead center to set the first intake valve closing period, and sets the closing timing of the intake valve before the intake bottom dead center. The second intake valve closing period is controlled to generate a non-equilibrium plasma discharge until the end of the first intake valve closing period, and after the first intake valve closing period ends, The voltage application means is controlled to generate a non-equilibrium plasma discharge until
The engine according to claim 1 or 2, characterized by the above. Fuel supply means for supplying fuel to the engine;
The control means controls the fuel supply means to supply fuel before the intake valve opens;
The engine according to claim 5. The fuel supply means is configured to inject fuel directly into the combustion chamber and to direct the injected fuel to the discharge chamber.
The engine according to claim 6. The second electrode is formed so as to separate the discharge chamber and the combustion chamber, and includes a communication path that communicates the discharge chamber and the combustion chamber.
The engine according to any one of claims 1 to 5, characterized by that. A plurality of the communication passages are arranged uniformly in the circumferential direction of the substantially cylindrical second electrode;
The engine according to claim 8. A piston having a recess formed such that the crown surface of the piston is recessed;
A fuel supply means configured to inject fuel directly into the combustion chamber and to direct the injected fuel to the recess,
The second electrode is configured such that radicals flowing out from the communication path are directed to the recess,
The control means injects fuel by the fuel supply means during a compression stroke;
The engine according to claim 8. The engine is a compression ignition engine that compresses and burns an air-fuel mixture by a compression action of a compression stroke.
The engine according to any one of claims 1 to 10, characterized by that.