JP2018178749A - Internal combustion engine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent fuel introduced into a sack chamber from outflowing from an outlet part of an injection hole, in a case of pushing out gas from the sack chamber by introducing the fuel into the sack chamber prior to fuel injection into a cylinder.SOLUTION: A controller is configured to: execute a gas pushing-out process of opening a sack chamber before injecting fuel into a cylinder, and moving a needle valve so as to introduce fuel into the sack chamber; and in executing the gas pushing-out process, determine the movement distance and movement frequency of the needle valve so that a flow rate of fuel passing through a gap between the needle valve and an injection device body never exceeds a predetermined threshold, and that a total flow rate of fuel passing through the gap never exceeds a total value of the volumes of the sack chamber and an injection hole.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an internal combustion engine system provided with a fuel injection device that injects fuel into a cylinder of an internal combustion engine, and a control device that controls the fuel injection device.

  An internal combustion engine system that obtains power by burning fuel in a cylinder includes a fuel injection device for injecting fuel into the cylinder. This fuel injection device is provided inside a hollow injection device main body in which a suck chamber capable of storing fuel is formed at the tip end portion, and the injection device main body, and moves up and down so as to close or open the suck chamber. And a needle valve. Then, when the needle valve ascends to open the suck chamber, the high-pressure fuel introduced into the injection device main body flows into the suck chamber, and the fuel flows into the cylinder through the injection hole formed at the tip of the injection device main body. It is injected to.

  Here, at the start of fuel injection by the fuel injection device, gas such as air may be present in the sac chamber that should be filled with fuel. In this case, the fuel flowing into the suck chamber mixes with the gas, whereby the flow of fuel in the suck chamber becomes unstable. As a result, the distribution of fuel injected from the injection holes becomes uneven, and the problem of exhaustion of soot, unburned fuel and the like into the exhaust gas arises.

  Therefore, in order to solve such a problem, there is known a technology for removing gas from the suck chamber by slightly raising the needle valve only once and injecting the fuel into the suck chamber before injecting the fuel (see See, for example, Patent Document 1). In this fuel injection device, the amount of movement of the needle valve depends on the pressure difference between the upstream and downstream sides of the needle valve, and the total flow of fuel introduced into the suck chamber does not exceed the volume of the suck chamber. It is set. The fuel introduced into the suck chamber is retained in the injection hole without being injected from the outlet of the injection hole due to the surface tension of the fuel.

JP, 2014-015894, A

  However, in the conventional internal combustion engine system, the flow rate of the fuel flowing into the suck chamber is increased because the suck chamber is filled with fuel by raising the needle valve only once. As a result, there arises a problem that the fuel introduced into the suck chamber flows out of the outlet of the injection hole into the cylinder against the surface tension.

  Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to sack the case where gas is expelled from the sack chamber by introducing the fuel into the sack chamber of the fuel injection device prior to the injection of the fuel into the cylinder. An object of the present invention is to provide an internal combustion engine system capable of preventing the fuel introduced into the chamber from flowing out from the outlet of the injection hole.

According to one aspect of the invention,
A fuel injection device for injecting fuel into a cylinder of an internal combustion engine;
A control device configured to control the fuel injection device;
Equipped with
The fuel injection device
A hollow injection device main body having a suck chamber capable of storing fuel, and an injection hole communicating the suck chamber and the inside of the cylinder;
A needle valve movably provided inside the injector main body so as to close or open the suck chamber;
The controller is
Before injecting the fuel into the cylinder, a gas ejection process is performed to move the needle valve so as to open the suck chamber and introduce the fuel into the cylinder;
When performing the gas ejection process, the total flow rate of the fuel passing through the gap is controlled so that the flow velocity of the fuel passing through the gap between the needle valve and the injector main body does not exceed a predetermined threshold. An internal combustion engine system is provided, characterized in that the moving distance and the number of movements of the needle valve are determined so as not to exceed the sum of the volume of the chamber and the injection hole.

In the internal combustion engine system according to one aspect of the present invention,
The control device may determine the moving distance of the needle valve in accordance with the pressure difference between the upstream side and the downstream side of the needle valve within a range in which the flow velocity of the fuel passing through the gap does not exceed a predetermined threshold. .

In the internal combustion engine system according to one aspect of the present invention,
The controller may calculate the flow velocity of the fuel passing through the gap based on the Hagen-Poiseuille equation.

In the internal combustion engine system according to one aspect of the present invention,
The control device may execute the gas removal process upon cold start of the internal combustion engine or upon recovery from fuel cut.

  According to the internal combustion engine system according to one aspect of the present invention, when the gas is expelled from the suck chamber by introducing the fuel into the suck chamber of the fuel injection device prior to the injection of the fuel into the cylinder, It is possible to prevent the introduced fuel from flowing out from the outlet of the injection hole.

1 is a schematic view showing an internal combustion engine system 1 according to an embodiment of the present invention. FIG. 1 is a schematic vertical cross-sectional view showing a configuration of a fuel injection device 10. FIG. 2 is a partially enlarged cross-sectional view of a tip end portion of the fuel injection device 10; FIG. 5 is a partially enlarged cross-sectional view in which the periphery of the injection hole 23 at the tip of the fuel injection device 10 is enlarged. FIG. 2 is a partially enlarged cross-sectional view of a tip end portion of the fuel injection device 10; It is a flowchart which shows the flow of gas expelling processing. It is a flow chart which shows a flow of movement distance decision processing of needle valve 16. It is a flowchart which shows the flow of the movement frequency determination processing of the needle valve 16. FIG. FIG. 2 is a partially enlarged cross-sectional view of a tip end portion of the fuel injection device 10;

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

(Configuration of internal combustion engine system)
FIG. 1 is a schematic view showing an internal combustion engine system 1 according to an embodiment of the present invention. The internal combustion engine system 1 includes an internal combustion engine 2, an intake passage 3 for supplying intake air drawn from the outside to the internal combustion engine 2, an exhaust passage 4 for discharging the exhaust gas discharged from the internal combustion engine 2 to the outside, The operation of each part is controlled based on the detection results obtained from various sensors and the like, the EGR device 5 for recirculating a part of the exhaust gas into the intake passage 3, the exhaust gas purification device 6 for purifying the exhaust gas flowing through the exhaust passage 4 And a control device 7 for

  The internal combustion engine 2 is a four-cylinder compression ignition internal combustion engine mounted on a vehicle, that is, a diesel engine. The internal combustion engine 2 has an internal combustion engine body 8 and a fuel injection unit 9 as shown in FIG. Although the illustrated example shows the in-line four-cylinder internal combustion engine 2, the cylinder arrangement type of the internal combustion engine 2, the number of cylinders, and the like are arbitrary.

  The internal combustion engine body 8 includes structural parts such as a cylinder head, a cylinder block, and a crankcase, and movable parts such as a piston, a crankshaft, and a valve accommodated therein, though not shown in detail in the figure. As shown in FIG. 1, four cylinders 81 are formed in the internal combustion engine body 8.

  The fuel injection unit 9 is a so-called common rail fuel injection unit, and plays a role of injecting fuel into the interior of the cylinder 81. As shown in FIG. 1, the fuel injection unit 9 includes a fuel injection device 10 provided in each of the cylinders 81, a common rail 11 for storing the fuel F to be supplied to the fuel injection device 10 in a high pressure state, and the common rail 11. A common rail pressure sensor 12 for detecting the internal pressure and an in-cylinder pressure sensor 13 for detecting the internal pressure of the cylinder 81 are provided.

  FIG. 2 is a schematic vertical sectional view showing the configuration of the fuel injection device 10. As shown in FIG. The fuel injection device 10 includes a hollow injection device main body 14, a solenoid 15 housed on the proximal end side inside the injection device main body 14, and a needle valve 16 similarly housed on the tip end side inside the injection device main body 14. And a needle spring 17 interposed between the injector main body 14 and the needle valve 16.

  The injector main body 14 plays a role of internally storing the fuel F to be injected into the cylinder. As shown in FIG. 2, the injection device main body 14 is a substantially cylindrical member having a conical outer end. The injection device body 14 has a proximal end cavity 18 formed on the proximal side, a distal cavity 19 formed on the distal end, and an introduction passage 20 communicating the distal cavity 19 with the outside. A discharge passage 21 communicating the proximal cavity 18 with the distal cavity 19, a recovery passage 22 communicating the proximal cavity 18 with the outside, and two injection holes formed at the distal end. And 23). Then, as shown in FIG. 2, the tip end side hollow portion 19 constitutes a pressure control chamber 191 having a substantially rectangular cross section which constitutes the uppermost portion, a fuel chamber 192 having a substantially pentagonal sectional shape which constitutes a central portion, and a lowermost portion. And a suck chamber 193 having a substantially semicircular cross section.

  The solenoid 15 serves to close or open the discharge passage 21 of the injector body 14. As shown in FIG. 2, the solenoid 15 is fixed to a fixing core 24 fixedly provided inside the proximal end cavity 18 and a solenoid coil 25 provided inside the fixing core 24. An armature 26 made of a conductive material is provided below the core 24 and spaced apart, and a return spring 27 provided between the fixing core 24 and the armature 26.

  According to the solenoid 15 configured as described above, when no current is applied to the solenoid coil 25, the armature 26 receiving the biasing force from the return spring 27 stops at the position at which the discharge path 21 is closed. On the other hand, when a current is applied to the solenoid coil 25, the fixing core 24 to which the electromagnetic force is applied from the solenoid coil 25 attracts the armature 26, whereby the armature 26 resists the biasing force of the return spring 27. Move to Thus, the discharge passage 21 is opened.

  The needle valve 16 serves to close or open the suck chamber 193 of the injector body 14. The needle valve 16 is a substantially cylindrical member as shown in FIG. 2 and has a servo piston portion 28 provided with a proximal end portion projecting in the radial direction, and an axial intermediate portion projecting in the radial direction. It has a nozzle piston portion 29 provided to be provided, a cone portion 30 provided with a tip portion formed in a substantially truncated cone shape, and a seating surface 31 provided at the base end portion of the cone portion 30. ing.

  The needle spring 17 plays a role of urging the needle valve 16 toward the tip end side of the injector main body 14. The needle spring 17 is a so-called compression spring, and as shown in FIG. 2, a spring receiving portion 33 provided radially on the inner side surface of the injection device main body 14 and a nozzle piston portion 29 of the needle valve 16. And in a compressed state.

  In the fuel injection device 10 configured as described above, the high-pressure fuel F stored in the common rail 11 (see FIG. 1) is introduced via the introduction passage 20 in a state where the armature 26 shown in FIG. It is introduced into the fuel chamber 192 and the pressure control chamber 191. Then, the sum of the force of the fuel F inside the pressure control chamber 191 pressing the servo piston portion 28 to the tip side and the force of the needle spring 17 biasing the nozzle piston portion 29 to the tip side The internal fuel F is greater than the force pressing the nozzle piston 29 toward the proximal end. As a result, the needle valve 16 is lowered, that is, moved to the tip side inside the distal cavity 19.

  Here, FIG. 3 is a partially enlarged cross-sectional view in which the front end portion of the fuel injection device 10 is enlarged. When the needle valve 16 is lowered, the seating surface 31 of the needle valve 16 is in close contact with the seat surface 34 which constitutes a part of the inner side surface of the injector main body 14. As a result, the suck chamber 193 provided on the front end side of the seat surface 34 is closed.

  Then, with the suck chamber 193 closed, as shown by the broken line in FIG. 2, when the discharge passage 21 is opened by the armature 26 being sucked by the fixing core 24, the fuel F introduced into the pressure control chamber 191 Is discharged to the proximal cavity 18 through the discharge passage 21, so that the internal pressure of the pressure control chamber 191 is reduced. Then, the force by which the fuel F inside the fuel chamber 192 presses the nozzle piston portion 29 to the base end side and the force by which the fuel F inside the pressure control chamber 191 presses the servo piston portion 28 to the tip side 17 is greater than the sum of the force with which the nozzle piston 29 is urged toward the tip end. As a result, the needle valve 16 moves upward, i.e., proximally, inside the distal cavity 19. The fuel F discharged to the proximal end cavity 18 is recovered to a fuel tank (not shown) via the recovery path 22.

  Here, FIG. 4 is a partially enlarged cross-sectional view in which the periphery of the injection hole 23 at the tip of the fuel injection device 10 is enlarged. When the needle valve 16 ascends inside the distal end side cavity 19, the seating surface 31 of the needle valve 16 separates from the seat surface 34 of the injector main body 14, and the suck chamber 193 is opened. As a result, the fuel F inside the fuel chamber 192 flows out to the front end side through the gap C created between the seating surface 31 of the needle valve 16 and the seat surface 34 of the injector main body 14. The fuel F having flowed out flows directly from the inlet portion 231 into the injection hole 23 without passing through the suck chamber 193 as shown by the solid arrow in FIG. By flowing into 193 and forming a vortex in the inside thereof and then flowing into the injection hole 23, it is injected from the outlet 232 to the inside of the cylinder 81 (shown in FIG. 1).

  As shown in FIG. 1, the control device 7 is electrically connected to the fuel injection device 10, the common rail pressure sensor 12, and the in-cylinder pressure sensor 13. The control device 7 configured as described above controls the operation of the fuel injection device 10 according to the detection results output from the common rail pressure sensor 12 and the in-cylinder pressure sensor 13.

(Flow of gas removal process)
Next, the gas purge process performed by the controller 7 will be described. FIG. 5 is a partially enlarged cross-sectional view in which the tip of the fuel injection device 10 is enlarged. When starting fuel injection from the fuel injection device 10 into the cylinder 81, a gas G such as air may be present in the sac chamber 193 which should be filled with the fuel F. In this case, the flow of the fuel F in the suck chamber 193 becomes unstable because the fuel F flowing into the suck chamber 193 mixes with the gas G. As a result, the distribution of the fuel F injected from the injection holes 23 becomes uneven, which causes a problem that exhaust gas, unburned fuel and the like are discharged into the exhaust gas. Therefore, in order to solve such a problem, prior to the injection of the fuel F, the needle valve 16 is slightly raised to introduce the fuel F into the suck chamber 193, thereby removing the gas G from the suck chamber 193, ie, A gas purge process is performed.

  In addition, the timing which performs this gas ejection process is not specifically limited, It is possible to perform at arbitrary timings. However, there is a possibility that the gas G is likely to be accumulated in the suck chamber 193, for example, at the time of cold start, that is, when starting the internal combustion engine 2 stopped for a long period, or at the time of recovery from fuel cut, Sometimes it is particularly effective to execute the gas purge process at the timing of resuming fuel injection by pressing an accelerator (not shown) after stopping fuel injection for improving fuel consumption. However, since the gas G may be accumulated in the suck chamber 193 even in the steady state of the internal combustion engine 2, the gas purge process may be performed in such a steady state.

  FIG. 6 is a flowchart showing the flow of the gas purge process. With the start of the gas ejection process at an arbitrary timing, the control device 7 first executes an upward distance determination process of the needle valve 16 (S1). Here, FIG. 7 is a flowchart showing the flow of the process of determining the ascent distance of the needle valve 16. With the start of the ascending distance determination process, the control device 7 first acquires the pressure on the upstream side and the pressure on the downstream side of the needle valve 16 (S4). In the present embodiment, the control device 7 detects the internal pressure of the common rail 11 detected by the common rail pressure sensor 12 shown in FIG. 1 as the pressure on the upstream side, and the pressure of the cylinder 81 detected by the in-cylinder pressure sensor 13 as the pressure on the downstream side. Obtain internal pressure respectively.

  Next, the controller 7 calculates the pressure difference between the upstream side and the downstream side of the needle valve 16 (S5). That is, the control device 7 calculates the pressure difference between the upstream side and the downstream side across the needle valve 16 by taking the difference between the pressure on the upstream side and the pressure on the downstream side of the needle valve 16 acquired in step S4.

  Then, based on the pressure difference calculated in step S5, the control device 7 acquires a provisional value for the ascent distance of the needle valve 16, ie, the movement distance to the base end side in FIG. 2 (S6). More specifically, as shown in FIG. 1, a map MP in which the pressure difference between the upstream side and the downstream side across the needle valve 16 is associated with the rising distance of the needle valve 16 in the control device 7 is shown. It is stored. The controller 7 obtains a provisional value of the ascent distance of the needle valve 16 corresponding to the pressure difference calculated in step S5 by referring to the map MP.

  Next, the control device 7 calculates an estimated flow velocity of the fuel F passing through the gap C between the needle valve 16 and the injection device main body 14 (S7). Specifically, the controller 7 regards the flow of the fuel F passing through the gap C as a laminar flow of a viscous fluid flowing inside a circular pipe having a constant pipe diameter, and based on the so-called Hagen-Poiseuille equation Thus, the estimated flow velocity of the fuel F is calculated. At the time of calculation, the provisional value of the ascent distance of the needle valve 16 acquired in step S6, the channel width of the gap C, the dynamic viscosity coefficient of the fuel F, and the like are used. In addition, it is also possible to correct the dynamic viscosity coefficient of the fuel F according to the temperature of the fuel F. In that case, if it is difficult to measure the temperature of the fuel F in the gap C, the temperature of the fuel F on the upstream side of the gap C or the temperature of the injector main body 14 may be used instead.

  Next, the controller 7 determines whether the calculated estimated flow velocity of the fuel F is larger than a predetermined threshold (S8). As a result, when it is determined that the estimated flow velocity of the fuel F is larger than the threshold (S8: Yes), the control device 7 determines the rising distance of the needle valve 16 to a predetermined value (S9). The predetermined value is preset as a predetermined value at which the calculated estimated flow velocity does not become larger than the threshold when the estimated flow velocity of the fuel F is calculated using the predetermined value in step S7.

  On the other hand, as a result of the determination in step S8, when it is determined that the estimated flow velocity of fuel F is less than or equal to the threshold (S8: No), controller 7 determines the ascending distance of needle valve 16 to the provisional value acquired in step S6. To do (S10). Thus, the process of determining the ascent distance of the needle valve 16 shown in FIG. 7 ends.

  Next, as shown in FIG. 6, the control device 7 executes the process of determining the number of times of rising of the needle valve 16 (S2). Here, FIG. 8 is a flow chart showing a flow of processing for determining the number of times of rising of the needle valve 16. With the start of the rise number determination process, the controller 7 first sets the number of times the needle valve 16 is raised to one (S11).

  Then, the controller 7 calculates the total flow rate of the fuel F passing through the gap C shown in FIG. 4 by one rise of the needle valve 16 (S12). Then, the control device 7 determines whether the calculated total flow rate of the fuel F is larger than the sum of the volume of the suck chamber 193 and the volume of each injection hole 23 (S13). As a result, when it is determined that the total flow rate of the fuel F having passed through the gap C is equal to or less than the total value of the volume of the suck chamber 193 and the volume of each injection hole 23 (S13: No), the controller 7 controls the needle valve 16 The number of rises is increased once (S14). Then, the control device 7 returns to step S12, and recalculates the total flow rate of the fuel F passing through the gap C by the two upward movements of the needle valve 16. Thereafter, the control device 7 performs the step until the total flow rate of the fuel F passing through the gap C is determined to be larger than the sum of the volume of the suck chamber 193 and the volume of each injection hole 23 in step S13 (S13: Yes) The processes of 12, 13 and 14 are repeatedly executed.

  Thereafter, in the determination in step S13, it is determined that the total flow rate of the fuel F passing through the gap C is larger than the sum of the volume of the suck chamber 193 and the volume of each injection hole 23 S13: Yes), the control device 7 decreases the number of ascent of the needle valve 16 one time, and determines the value after the decrease as the number of ascent of the needle valve 16 (S15). As described above, the process for determining the number of times of ascent of the needle valve 16 shown in FIG. 8 ends.

  Finally, as shown in FIG. 6, the control device 7 executes the lifting process of the needle valve 16 (S3). Here, FIG. 9 is a partially enlarged cross-sectional view in which the front end portion of the fuel injection device 10 is enlarged. From the state shown in FIG. 5, the control device 7 raises the needle valve 16 by the rising distance H determined in the rising distance determination processing. Thus, the fuel F inside the fuel chamber 192 flows into the injection hole 23 and the suck chamber 193 through the gap C created between the seating surface 31 of the needle valve 16 and the seat surface 34 of the injection device main body 14. Do. Then, after raising the needle valve 16 for a predetermined time, the control device 7 brings the seating surface 31 of the needle valve 16 into close contact with the seat surface 34 of the injection device main body 14 by lowering the needle valve 16 ( Shown in FIG. 9 by a broken line). Thereby, the suck chamber 193 is closed. The controller 7 repeats such a single up and down movement of the needle valve 16 for the number of times of increase determined in the process of determining the number of times of increase. Thus, the lifting process of the needle valve 16 is completed.

  Here, in the ascending distance determination process shown in FIG. 6, since the ascending distance of the needle valve 16 is determined in the range where the estimated flow rate of the fuel F does not increase beyond the threshold, the fuel F passing through the gap C has its flow velocity It is relatively slow, so its kinetic energy is relatively small. Therefore, the fuel F that has flowed downstream through the gap C is retained by the surface tension of the fuel in the suck chamber 193 and the injection hole 23 without flowing out from the outlet 232 of the injection hole 23 into the cylinder 81. Ru.

  Further, in the rise number determination process shown in FIG. 6, the number of movements of the needle valve 16 is determined so that the total flow rate of the fuel F passing through the gap C does not exceed the sum of volumes of the suck chamber 193 and the injection hole 23. Accordingly, the outflow of the fuel F from the outlet portion 232 of the injection hole 23 is further prevented, and the fuel F which has flowed out to the downstream side through the gap C is held inside the suck chamber 193 and the injection hole 23.

  As described above, according to the fuel injection device 10 according to the embodiment of the present invention, the gas G is expelled from the suck chamber 193 by introducing the fuel F into the suck chamber 193 prior to the injection of the fuel F into the cylinder 81 In addition, the fuel F introduced into the suck chamber 193 can be prevented from flowing out from the outlet portion 232 of the injection hole 23.

(Modification)
As mentioned above, although embodiment of this invention was described in detail, the modification as shown below is also considered as embodiment of this invention.

  (1) In the present embodiment, the internal pressure of the common rail 11 is acquired by the common rail pressure sensor 12 in order to acquire the pressure on the upstream side of the needle valve 16. However, instead of this, for example, the internal pressure of the proximal end cavity 18 of the injector main body 14 may be obtained as a pressure on the upstream side of the needle valve 16 by a pressure sensor (not shown).

  (2) In the present embodiment, in order to acquire the pressure on the downstream side of the needle valve 16, the internal pressure of the cylinder 81 is acquired by the in-cylinder pressure sensor 13. However, instead of this, it is also possible to hold in advance in the control device 7 a map (not shown) in which the crank angle which is the rotation angle of the internal combustion engine 2 and the internal pressure of the cylinder 81 correspond to each other. In this case, the control device 7 may detect the crank angle and acquire the internal pressure of the cylinder 81 derived by referring to the map as the pressure on the downstream side of the needle valve 16.

  (3) In the present embodiment, the rise distance of the needle valve 16 is first determined in consideration of the estimated flow velocity of the fuel F, and then the number of times of rise of the needle valve 16 is determined in consideration of the total flow rate of the fuel F. However, after the number of ascent of the needle valve 16 is determined to be a predetermined number, the ascent distance of the needle valve 16 may be determined in consideration of the estimated flow velocity and the total flow rate of the fuel F.

1 internal combustion engine system 2 internal combustion engine 7 control device 10 fuel injection device 14 injection device main body 16 needle valve 23 injection hole 81 cylinder 193 suck chamber C clearance F fuel H rise distance (travel distance)

Claims (4)

A fuel injection device for injecting fuel into a cylinder of an internal combustion engine;
A control device configured to control the fuel injection device;
Equipped with
The fuel injection device
A hollow injection device main body having a suck chamber capable of storing fuel, and an injection hole communicating the suck chamber and the inside of the cylinder;
A needle valve movably provided inside the injector main body so as to close or open the suck chamber;
The controller is
Before injecting the fuel into the cylinder, a gas ejection process is performed to move the needle valve so as to open the suck chamber and introduce the fuel into the cylinder;
When performing the gas ejection process, the total flow rate of the fuel passing through the gap is controlled so that the flow velocity of the fuel passing through the gap between the needle valve and the injector main body does not exceed a predetermined threshold. An internal combustion engine system, wherein the movement distance and the number of movements of the needle valve are determined so as not to exceed the total value of the volume of the chamber and the injection hole. The control device determines the moving distance of the needle valve in accordance with the pressure difference between the upstream side and the downstream side of the needle valve in a range where the flow velocity of the fuel passing through the gap does not exceed a predetermined threshold. The internal combustion engine system according to claim 1, wherein The internal combustion engine system according to claim 1 or 2, wherein the control device calculates the flow velocity of the fuel passing through the gap based on Hagen-Poiseuille equation. The internal combustion engine system according to any one of claims 1 to 3, wherein the control device executes the gas purge processing at the time of cold start or fuel return of the internal combustion engine.

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