JP2006097571A - Internal combustion engine provided with supercharger with gas storage tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine provided with a supercharger with a gas storage tank capable of securing sufficient storage quantity of higher pressure gas. <P>SOLUTION: This invention relates to the internal combustion engine 1 provided with the supercharger 2 capable of promoting supercharge by supplying gas stored in the gas storage tank 6 to a suction gas passage 3 or a exhaust gas passage 4, and provided with a boosting means 7 boosting gas to be stored in the gas storage tank 6 by using pressure difference inside of the internal combustion engine 1. Pressure of gas in the gas storage tank 6 can be made higher by increasing pressure of gas to be stored in the gas storage tank 6 by using pressure difference inside of the internal combustion engine 1, supply quantity at a time of supply of gas in the gas storage tank 6 to a suction exhaust system can be increased and supercharge promotion effect can be improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine including a supercharger that can perform supercharging promotion using an air storage tank.

An intake tank is provided in the intake / exhaust system of an internal combustion engine equipped with a supercharger, and high-pressure gas (usually intake air or exhaust gas) stored in the intake tank is supplied to the intake system or exhaust system. Some promote supercharging. When the gas is supplied to the intake system, the intake air amount increases, so that supercharging is promoted (for example, [Patent Document 1]). When gas is supplied to the exhaust system, driving of the turbocharger turbine is promoted, so that supercharging is promoted.
JP-A-1-166724

  In the conventional supercharger with an air storage tank, gas is stored using the supercharging pressure in the air storage tank, and therefore there is a limit to the pressure and the amount of gas that can be stored. For this reason, the supercharging promotion effect using stored air was not sufficiently obtained. It is also conceivable to secure a large capacity of the air storage tank in order to increase the amount of gas that can be stored, but it is difficult to mount due to space problems. For this reason, a supercharger with a storage tank that can secure a sufficient storage amount at a higher pressure has been demanded. An object of the present invention is to provide an internal combustion engine including a supercharger with an air storage tank capable of securing a sufficient air storage amount at a higher pressure.

  The invention according to claim 1 is an internal combustion engine provided with a supercharger capable of promoting the supercharging by supplying the gas stored in the air storage tank to the intake passage or the exhaust passage, and the differential pressure inside the internal combustion engine is reduced. It is characterized by having a pressure increasing means for increasing the pressure of gas stored in the air storage tank.

  According to a second aspect of the present invention, in the internal combustion engine provided with the supercharger with the air storage tank according to the first aspect, the pressure increasing means utilizes the negative pressure in the intake passage during the idling operation of the internal combustion engine. It is characterized by increasing the pressure of the gas.

  According to a third aspect of the present invention, in the internal combustion engine having the supercharger with an air storage tank according to the first aspect, the supercharger has a variable nozzle mechanism, and the variable nozzle mechanism is in a predetermined condition. The nozzle is controlled to the closed side, and the pressure increasing means increases the pressure of the gas by utilizing the pressure fluctuation in the exhaust passage caused by the control to the closed side of the nozzle by the variable nozzle mechanism.

  According to the internal combustion engine provided with the supercharger with an air storage tank according to claim 1, the pressure of the gas stored in the air storage tank is increased using the pressure difference inside the internal combustion engine. By increasing the pressure, the pressure of the gas in the storage tank can be increased, the supply amount when supplying the gas in the storage tank to the intake / exhaust system can be increased, and the supercharging promotion effect is enhanced. can do. By boosting supercharging, it is possible to improve fuel efficiency, reduce carbon dioxide emissions associated with it, and improve output. Further, since the gas can be stored in the air storage tank at a higher pressure, the size of the air storage tank can be reduced and the mountability is improved. In addition, since the internal pressure of the internal combustion engine is used for pressure increase, there is no need to add an extra structure, and no new energy consumption source (pump, motor, etc.) is required for pressure increase. Is also good.

  According to the internal combustion engine provided with the supercharger with the air storage tank according to claim 2, more effective pressure increase can be performed by using the negative pressure in the intake passage, and even better A supercharging promotion effect can be obtained. The larger the pressure difference when the pressure increasing means performs pressure increase, the better. By using the negative pressure in the intake passage on the low pressure side, the gas stored in the air storage tank can be increased to a higher pressure. In particular, when the internal combustion engine is idling, there is a stable negative pressure in the intake passage, so that pressure can be increased even when idling.

  According to the internal combustion engine having the supercharger with the air storage tank according to claim 3, it is more effective by utilizing the pressure fluctuation generated before and after the turbine of the supercharger using the variable nozzle mechanism. Pressure increase can be performed, and an even better boosting effect can be obtained. The pressure fluctuation at this time can use the pressure increase on the upstream side of the turbine caused by controlling the nozzle of the variable nozzle mechanism to the closed side (for example, increasing by controlling the nozzle of the variable nozzle mechanism to the closed side). Use the pressure difference between the front and back of the turbine. The larger the differential pressure when the pressure increasing means performs pressure increase, the better. By utilizing the pressure fluctuation described above, the gas stored in the air storage tank can be increased to a higher pressure. In particular, when the internal combustion engine is in an idle state, the nozzle is controlled to be closed by a variable nozzle mechanism. However, since the pressure fluctuation generated at this time can be used, the pressure can be increased even in an idle state.

  An embodiment of an internal combustion engine provided with a supercharger with an air storage tank of the present invention will be described below. In FIG. 1, the block diagram of the internal combustion engine provided with the supercharger with the air storage tank of 1st embodiment is shown. An engine (internal combustion engine) 1 is a drive source of a vehicle and includes a turbocharger (supercharger) 2. The turbocharger 2 is disposed between the intake passage 3 and the exhaust passage 4 as usual. The turbine wheel 2a of the turbocharger 2 is rotated by the exhaust flow, and accordingly, the compressor wheel 2b connected to the turbine wheel 2a is rotated to perform supercharging. A pressure sensor 5 that detects a supercharging pressure is disposed downstream of the compressor wheel 2 b in the intake passage 3.

  The engine 1 is also mounted with an air storage tank 6. The gas storage tank 6 stores a gas (intake air in the present embodiment) with an increased pressure sent from a pressure increasing valve (pressure increasing means) 7 which will be described in detail later. When supercharging promotion is required, the valve 9 is opened and the gas stored in the air storage tank 6 is supplied to the intake passage 3 to increase the intake air amount and promote supercharging. A pressure sensor 8 that detects the pressure of the gas stored inside is attached to the air storage tank 6.

  When the gas stored in the air storage tank 6 is supplied to the intake passage 3, the gas pressure in the air storage tank 6 is high, so that the valve 9 is only opened even if the supercharging pressure is generated in the intake passage 3. Can be supplied at. The valve 9 may be of a mechanism that simply opens and closes, or may be of a mechanism that can adjust the opening degree (including that based on a DUTY ratio). In the latter case, it is possible to variably adjust the supercharging promotion effect by adjusting the supply gas amount.

  In the present embodiment, the case where the gas stored in the air storage tank 6 is supplied to the intake passage 3 to promote supercharging will be described. However, it is also conceivable to supply the exhaust passage 4 to promote supercharging. . In this case, as shown by the dotted line in FIG. 1, the valve 10 is provided, and the valve 10 is opened to supply the gas stored in the air storage tank 6 to the exhaust passage 4, thereby increasing the exhaust flow rate and supercharging. Promote. When the gas stored in the air storage tank 6 is supplied to the exhaust passage 4, the gas pressure in the air storage tank 6 is high, so that the gas can be supplied only by opening the valve 10. The valve 10 may be a mechanism that merely opens and closes, or may be a mechanism that can adjust the opening degree. In the latter case, supercharging is performed by adjusting the amount of supplied gas. It is possible to variably adjust the promoting effect.

  The pressure increasing valve 7 increases the pressure of the gas taken in from the primary side (suction side) and sends it out to the secondary side (pressure increase side). At this time, in the present embodiment, the pressure is increased by utilizing a differential pressure between the gas pressure on the primary side and the exhaust side (atmosphere in the present embodiment). The pressure can be increased when the primary pressure is higher than the exhaust pressure. Moreover, it can increase to a higher pressure, so that a differential pressure | voltage is large. Note that a valve 11 that is opened only when the air is stored in the air storage tank 6 is provided on the primary side that takes in the gas.

  In the present embodiment, the primary side is connected to the intake passage 3 downstream of the compressor wheel 2b. For this reason, when the pressure downstream of the compressor wheel 2b is lower than the atmospheric pressure, the valve 11 is closed because the pressure cannot be increased. The valve 11 is also closed when it is determined that other conditions do not suit the storage. The pressure sensors 5 and 8 and the valves 9 to 11 described above are connected to a controller (not shown), and send detection results or are controlled by drive signals from the controller.

  FIG. 2 is a sectional view showing only the pressure increasing valve 7 in a large scale. The structure of the pressure increasing valve 7 is a known one. The gas (intake air) supplied from the primary side is supplied to the pressure increasing chamber 700 or the pressure increasing chamber 701 through the check valve. The intake air is charged into the pressure increasing chamber 700 when the piston 702 moves to the right in the drawing, and is filled into the pressure increasing chamber 701 when the piston 702 moves to the left in the drawing. The pressure increasing chamber 700 and the pressure increasing chamber 701 are also connected to the secondary side via check valves. Therefore, when the piston 702 moves to the left in the drawing, the intake air increased in pressure in the pressure increasing chamber 700 is discharged to the secondary side, and increases when the piston 702 moves to the right in the drawing. The increased intake air in the pressure chamber 701 is discharged to the secondary side.

  On the other hand, the intake air supplied from the primary side is also supplied to the drive chamber 705 or the drive chamber 706 via the governor 703 and the switching valve 704. The governor 703 receives the feedback of the gas pressure after the pressure increase discharged to the secondary side, and adjusts the pressure of the intake air supplied to the drive chamber 705 or the drive chamber 706 from the primary side, thereby finally It has a role to adjust the gas pressure after pressure increase discharged to the secondary side. The switching valve 704 switches whether the intake air is supplied to the driving chamber 705 or the driving chamber 706.

  The switching valve 704 is switched by being pushed by the piston 702, and the state shown in FIG. 1 is immediately after the piston 702 has moved to the right and the leftward movement is started. Therefore, the plunger of the switching valve 704 is pushed from the drive chamber 706 side and protrudes into the pressure increasing chamber 700. At this time, the intake air is supplied to the drive chamber 706 by the switching valve 704 as shown in the figure. At the same time, the drive chamber 705 communicates with the exhaust side (atmosphere). When the movement to the right is started after the piston 702 has moved to the leftmost, the plunger of the switching valve 704 is pushed from the pressure increasing chamber 700 side and protrudes into the driving chamber 706. At this time, the intake air is supplied to the drive chamber 705 by the switching valve 704. At the same time, the drive chamber 706 communicates with the exhaust side (atmosphere).

  In the state of the switching valve 704 in FIG. 2, if the pressure in the drive chamber 706 communicating with the primary side is higher than the atmospheric pressure communicating with the drive chamber 705, the piston is not shown due to the differential pressure between the drive chambers 705 and 706. As shown in FIG. 2, it is moved to the left in the figure. At this time, the gas in the pressure increasing chamber 700 is increased in pressure and discharged to the secondary side. On the other hand, if the drive chamber 706 is communicated to the atmospheric pressure by the switching valve 704 and the drive chamber 705 is communicated to the primary side (> atmospheric pressure), the piston is caused by the differential pressure between the drive chambers 705 and 706. Is moved to the right in the figure, and the gas in the pressure increasing chamber 701 is increased and discharged to the secondary side. 2, the area of the piston 702 on the drive chambers 705 and 706 side is larger than the area of the piston 702 on the pressure increase chambers 700 and 701, so that the pressure is increased more efficiently. It has been made so that it can.

  The control and the air storage tank when the air storage tank 6 stores air in the engine 1 having the above-described configuration will be described. First, in the case of storing air in the air storage tank 6, in the case of this embodiment, the primary side of the pressure increasing valve 7 is connected to the intake passage 3 on the downstream side of the compressor wheel 2b. For this reason, air is stored when the pressure on the primary side is sufficiently high and the decrease in the output of the engine 1 due to the stored air is not a problem.

  Specifically, the engine speed is equal to or higher than a predetermined speed, the engine output is sufficient, the pressure in the air storage tank 6 detected by the pressure sensor 8 is lower than a predetermined value, and the air is not stored enough. When the supercharging pressure detected by the pressure sensor 5 is equal to or higher than a predetermined pressure suitable for storing air, the valve 11 is opened and pressure increasing / accumulating is executed. Naturally, the valve 9 is closed when storing air.

  On the other hand, when the engine speed is lower than the predetermined speed, the accelerator opening is equal to or greater than the predetermined opening, the output increase is required, and the pressure in the air storage tank 6 detected by the pressure sensor 8 is a predetermined value. If the air is higher and the air is sufficiently stored, the valve 9 is opened and the supercharging is promoted using the gas in the air storage tank 6. Naturally, the valve 11 is closed when supercharging is promoted by storing air. Note that, in situations other than those described above, the valves 9 and 11 are both closed, and neither air storage nor supercharging is performed.

  In this way, the gas can be stored at a pressure obtained by further increasing the supercharging pressure, and effective supercharging can be promoted. Further, since the air is stored at a pressure exceeding the supercharging pressure, a large amount of gas can be used for supercharging promotion at the time of supercharging promotion, which is effective for acceleration at high vehicle speeds. Although the intake air in the intake passage 3 is used on the primary side here, the exhaust gas on the exhaust passage 4 side can be used on the primary side. In this case, since the exhaust gas is stored in the air storage tank 6, it is preferable to supply the stored exhaust gas to the exhaust passage 4 side to promote supercharging. However, it is also conceivable to supply EGR to the intake passage 3 side.

  Next, a second embodiment will be described. FIG. 3 shows a diagram corresponding to FIG. 1 of the present embodiment. In addition, since the structure of the engine 1 of this embodiment is based on the engine 1 of 1st embodiment mentioned above, the same code | symbol is attached | subjected about the same or equivalent component, and the detailed description is abbreviate | omitted. Only the different parts will be described below. Further, the pressure increasing valve 7 is the same as that of the first embodiment.

  In the present embodiment, the differential pressure used when the pressure is increased by the pressure increasing valve 7 is obtained more efficiently, and the air can be stored even during the idling operation. As a configuration, a throttle valve 12 is provided on the downstream side of the compressor wheel 2b. The throttle valve 12 may be for controlling the amount of intake air, or may be a so-called sub-throttle valve that adjusts the pressure in the intake passage 3. When the throttle valve 12 functions as a sub-throttle valve, a main throttle valve is provided on the upstream side (for example, upstream side of the compressor wheel 2b).

  Further, the above-described valve 11 is a switching valve, and switches between whether the intake air supplied as the primary side is introduced from the downstream side of the throttle valve 12 or the upstream side of the compressor wheel 2b. be able to. Note that the valve 11 may be closed. Further, the exhaust side of the pressure increasing valve 7 is not communicated with the atmosphere, but is communicated with the intake passage 3 via the valve 13. The valve 13 is also a switching valve, and it can be switched between the exhaust side and the upstream side of the compressor wheel 2b that communicates with the downstream side of the throttle valve 12 described above. The valve 13 can also be closed.

  The control at the time of storing air in the air storage tank 6 in the engine 1 having the above-described configuration will be described. In the engine of FIG. 1, air is stored only at high rotation and high load, but in the present embodiment, air can be stored even during idle operation. During the idle operation, the valves 11 and 13 are connected as indicated by the one-dot dashed line in FIG. Further, the throttle valve 12 is controlled to be closed as indicated by a dotted line (restricted to the intake air amount necessary for idling). In this case, the primary side is almost atmospheric pressure on the upstream side of the compressor wheel 2b. On the other hand, the exhaust side has a negative pressure in the intake passage 3 immediately after the throttle valve 12. This differential pressure is used to increase pressure and store air.

  Further, at the time of high speed and high load, the valves 11 and 13 are connected as shown by a solid line in FIG. Further, the throttle valve 12 is controlled to be opened as shown by the solid line (the intake air amount necessary for high output is sufficiently sucked). In this case, the primary side becomes the supercharging pressure on the downstream side of the throttle valve 12 (high because of high load). On the other hand, the pressure on the exhaust side becomes the pressure in the intake passage 3 on the upstream side of the compressor wheel 2b (approximately atmospheric pressure or negative pressure). This differential pressure is used to increase pressure and store air. In this way, air can be stored even at idle and at high speed and high load, and the air storage tank 6 can always store a sufficient amount of pressure and amount of air. Supercharging using the stored air at any time It can be promoted.

  Next, a third embodiment will be described. FIG. 4 shows a diagram corresponding to FIG. 1 of the present embodiment. FIG. 5 shows the pressure increasing valve 70 of the present embodiment. In addition, since the structure of the engine 1 (pressure increase valve 70) of this embodiment is also the same as the engine 1 (pressure increase valve 7) of 1st embodiment mentioned above, the same code | symbol is attached | subjected about the same or equivalent component. Detailed description thereof is omitted. Only the different parts will be described below.

  In this embodiment, exhaust gas is used instead of the primary side gas as the gas introduced into the drive chambers 705 and 706 of the pressure increasing valve 70 for pressure increase. For this reason, as shown in FIG. 5, the primary suction path and the drive suction path are separated. About another structure, it is the same as that of the pressure increase valve 7 of 1st embodiment. Further, with respect to the engine 1, the above-described suction passage for driving the pressure increasing valve 70 is connected to the exhaust passage 4 on the upstream side of the turbine wheel 2 a via the cooler 14 in the first embodiment. The cooler 14 lowers the temperature of the exhaust gas used for driving and prevents the pressure increase valve 70 from overheating. Further, since the driving gas is exhaust gas, it is necessary to return the exhaust gas to the exhaust passage 4 after driving the piston 702 (air release or the like is not preferable), and the exhaust side of the pressure increasing valve 70 is located downstream of the turbine wheel 2a. It is connected to the exhaust passage 4.

  The engine 1 of the present embodiment is a diesel engine, and a variable nozzle mechanism 15 is incorporated in the turbocharger 2. Even in this embodiment, air can be stored during idling. During idling, the nozzle of the variable nozzle mechanism 15 is controlled to the closed side. As a result, the pressure on the upstream side of the turbine wheel 2a increases. The pressure increasing valve 70 uses the pressure on the upstream side of the turbine wheel 2a as the driving gas pressure, uses the pressure on the downstream side of the turbine wheel 2a as the exhaust side pressure, and uses this differential pressure to increase and store air. . In particular, the nozzle of the variable nozzle mechanism 15 is controlled to be closed during idle operation, and the differential pressure before and after the turbine wheel 2a generated at this time can be used, so that pressure can be increased even during idling. At high speed and high load, a sufficient differential pressure is generated before and after the turbine wheel 2a even when the opening of the nozzle is opened, so that pressure increase and storage can be performed using the differential pressure before and after the turbine wheel 2a.

  In any of the above-described embodiments, since the pressure increasing valve 7 includes the piston 702, the pressure increasing valve 7 is not resistant to vibration. For this reason, it is preferable that the pressure increasing valve 7 is not attached to the engine body but attached to the body side of the vehicle. Further, the stroke direction of the piston 702 of the pressure increasing valve 7 is perpendicular to the vehicle front-rear direction and horizontal to the ground so that the movement of the piston 702 is less affected by the vehicle front-rear acceleration. It is preferable to do. Further, it is preferable that the pressure increasing valve 7 has a vibration-resistant support structure against body vibration.

  The internal combustion engine of the present invention is not limited to the embodiment described above. For example, although the turbocharger is used as a supercharger in the above-described embodiment, the present invention can also be applied to a case where a mechanical supercharger or the like is used as a supercharger. Moreover, the pressure for obtaining the differential pressure used for the pressure increase may be taken from the intake passage side, from the exhaust passage side, or atmospheric pressure may be used. Also good. The place for obtaining the pressure for obtaining the differential pressure may be properly used by a switching valve or the like depending on the situation. Further, the structure of the pressure increasing means (pressure increasing valve) is not limited to the above-described embodiment, and any structure may be used as long as the pressure is increased using the differential pressure inside the internal combustion engine.

It is a block diagram of 1st embodiment of the internal combustion engine provided with the supercharger with an air storage tank of this invention. It is sectional drawing of the pressure increase valve in embodiment of FIG. It is a block diagram of 2nd embodiment of the internal combustion engine provided with the supercharger with an air storage tank of this invention. It is a block diagram of 3rd embodiment of the internal combustion engine provided with the supercharger with the air storage tank of this invention. It is sectional drawing of the pressure increase valve in embodiment of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 2 ... Turbocharger (supercharger), 2a ... Turbine wheel, 2b ... Compressor wheel, 3 ... Intake passage, 4 ... Exhaust passage, 5, 8 ... Pressure sensor, 6 ... Air storage tank , 7, 70 ... pressure increasing valve (... pressure increasing means), 9 ... valve, 9, 10, 11, 13 ... valve, 12 ... throttle valve, 14 ... cooler, 15 ... variable nozzle mechanism, 700, 701 ... pressure increasing chamber 702, piston, 703, governor, 704, switching valve, 705, 706, drive chamber.

Claims (3)

In an internal combustion engine having a supercharger capable of promoting supercharging by supplying gas stored in an air storage tank to an intake passage or an exhaust passage,
An internal combustion engine equipped with a supercharger with an air storage tank, characterized by comprising pressure increasing means for increasing the pressure of gas stored in the air storage tank using a differential pressure inside the internal combustion engine.   2. The supercharger with an air storage tank according to claim 1, wherein the pressure increasing means increases the gas by using a negative pressure in the intake passage during an idling operation of the internal combustion engine. Internal combustion engine. The supercharger has a variable nozzle mechanism;
The variable nozzle mechanism controls the nozzle to the closed side under a predetermined condition,
2. The air storage tank according to claim 1, wherein the pressure increasing means increases the pressure of the gas by utilizing a pressure fluctuation in the exhaust passage caused by the control of the variable nozzle mechanism toward the closing side of the nozzle. An internal combustion engine equipped with a supercharger.

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