JP2007205302A - Engine intake control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fuel consumption quantity in a low rotation speed part load region by using an impulse valve without providing a special means such as a one valve deactivation mechanism. <P>SOLUTION: In an engine showing supercharging effect by increasing flow speed of intake air by opening and closing an intake port 16 by the impulse valve 32 in a low rotation speed heavy load region, open and close timing of the impulse valve 32 is retarded more than open and close timing in the low rotation speed heavy load region to reduce pumping loss accompanying open and close of the impulse valve 32 when fuel consumption quantity is reduced in the low rotation speed part load region by operating the impulse valve 32 for increasing flow speed of intake air and increasing combustion stability. Hence a fuel consumption quantity reduction effect is effectively shown by improvement of combustion stability accompanying increase of flow speed of intake air while limiting pumping loss to the minimum, and fuel consumption quantity is reduced without providing the special means such as the one valve deactivation mechanism to generate swirl in intake air. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intake control device for an engine that exerts a supercharging effect by opening and closing an intake port connected to a combustion chamber with an impulse valve in a low rotation and high load region of the engine.

  By opening and closing an impulse valve made up of a flap valve arranged in the intake passage of the engine at a predetermined timing in synchronization with the opening and closing of the intake valve, intake pulsation is generated in the intake passage even in a low engine speed and high load region. The thing which obtains a feeding effect is well-known by the following patent document 1. FIG.

Further, it is known from Patent Document 2 below that such an impulse valve is constituted by a ball valve, and its rotary shaft is reciprocally rotated by an actuator made of a rotary solenoid or an electric motor to open and close the intake passage.
JP 2000-248946 A JP 2005-344803 A

  By the way, the impulse valves described in Patent Documents 1 and 2 are intended to increase the charging efficiency of the intake air in the low rotation and high load region of the engine, and the partial load region is not considered. On the other hand, swirl and tumble are known as methods for improving combustion in a partial load region.

  In order to generate a swirl in the combustion chamber, a technique is known in which one of the two intake valves is deactivated by a one-valve deactivation mechanism. In this case, however, there is a problem that a complicated and expensive one-valve deactivation mechanism is required. is there. In addition, there is a known method of providing a fixed port in the combustion chamber in order to generate tumble in the combustion chamber. In this case, however, the combustion noise increases at high loads, or the effective opening area decreases to reduce the effective opening area. There is a problem that the output decreases.

  The present invention has been made in view of the above circumstances, and aims to reduce fuel consumption in a low rotation partial load region using an impulse valve without providing a special means such as a one-valve pause mechanism. Objective.

  In order to achieve the above object, according to the first aspect of the present invention, the intake air of the engine which opens and closes the intake port connected to the combustion chamber in the low rotation high load region of the engine by the impulse valve and exhibits the supercharging effect. In the control device, an engine intake control device is proposed, wherein the opening / closing timing of the impulse valve in the low rotation partial load region of the engine is advanced from the opening / closing timing in the low rotation / high load region. .

  According to the configuration of the first aspect, the engine that opens and closes the intake port with the impulse valve in the low rotation and high load region and increases the flow rate of the intake air to exert the supercharging effect impulses the intake port even in the low rotation partial load region. By increasing the intake air flow rate by opening and closing with a valve, the combustion stability can be increased and the fuel consumption can be reduced.However, since the pumping loss due to the operation of the impulse valve occurs, the fuel consumption due to the pumping loss is reduced. There is a problem that the decrease in the fuel consumption is offset by the increase. However, the pumping loss is reduced by advancing the opening / closing timing of the impulse valve in the low rotation partial load region relative to the opening / closing timing in the low rotation / high load region, and the combustion stability is improved as the intake air flow rate increases. The fuel consumption can be reduced without providing a special means such as a one-valve pause mechanism that effectively exerts the effect of reducing the fuel consumption by the above and generates a swirl in the intake air.

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

  1 to 17 show an embodiment of the present invention. FIG. 1 is a cross-sectional view of an engine cylinder head and an impulse valve, and FIG. 2 is an enlarged view of a main part of FIG. 1 (open state of the impulse valve). 3 is a view showing a closed state of the impulse valve corresponding to FIG. 2, FIG. 4 is a view in the direction of the arrow 4 in FIG. 2, FIG. 5 is a view in the direction of the arrow 5 in FIG. FIG. 7, FIG. 7 is an enlarged view of the main part of FIG. 2, FIG. 8 is an explanatory diagram of the action of the hydraulic shock absorber, FIG. 9 is a graph showing the operating region of the engine for operating the impulse valve, and FIG. FIG. 11 is a graph showing the relationship between the opening / closing timing of the impulse valve, FIG. 11 is a graph showing the relationship between the crank angle and the opening / closing timing of the impulse valve, and FIG. 12 is a graph showing the crank angle and the opening of the impulse valve in the low rotation partial load region of the engine. FIG. 13 is a graph showing the relationship between the indicated mean effective pressure IMEP and the fluctuation rate of the indicated mean effective pressure in the low rotation partial load region of the engine, and FIG. 14 is the indicated average in the low rotation partial load region of the engine. FIG. 15 is a graph showing the relationship between the effective pressure IMEP and the indicated fuel consumption rate ISFC, FIG. 15 is a graph showing the relationship between the indicated average effective pressure IMEP and the net fuel consumption rate BSFC in the low rotation partial load region of the engine, and FIG. FIG. 17 is a graph showing the relationship between the indicated mean effective pressure IMEP and the mean effective pump loss PMEP in the low rotation partial load region, and FIG. 17 is a graph showing the relationship between the crank angle and the intake flow coefficient.

  As shown in FIG. 1, a piston 13 is slidably fitted to a cylinder sleeve 12 provided in a cylinder block 11 of the engine E, and a cylinder head 14 coupled to a deck surface of the cylinder block 11 and a piston 13 are connected to each other. A combustion chamber 15 is defined between the top surface and the top surface. An intake port 16 and an exhaust port 17 connected to the combustion chamber 15 are formed in the cylinder head 14. An intake valve hole that opens the intake port 16 to the combustion chamber 15 is opened and closed by an intake valve 18, and the exhaust port 17 is opened to the combustion chamber. The exhaust valve hole opened to 15 is opened and closed by the exhaust valve 19. The intake valve 18 and the exhaust valve 19 are urged in the valve closing direction by valve springs 20 and 21, respectively.

  An intake camshaft 23 and an intake rocker arm shaft 24 are provided inside a head cover 22 coupled to the upper surface of the cylinder head 14, and are pivotally supported on the intake rocker arm shaft 24 by an intake cam 25 provided on the intake camshaft 23. The intake valve 18 is driven to open and close through the intake rocker arm 26. Further, an exhaust camshaft 27 and an exhaust rocker arm shaft 28 are provided inside the head cover 22, and an exhaust cam 29 provided on the exhaust camshaft 27 via an exhaust rocker arm 30 pivotally supported on the exhaust rocker arm shaft 28. The exhaust valve 19 is driven to open and close.

  An intake passage member 31 connected to the intake port 16, an impulse valve 32 made up of a ball valve, and an intake pipe 33 are connected to the cylinder head 14. A surge tank and a throttle valve (not shown) are connected upstream of the intake pipe 33. Be placed. The intake passage member 31 is provided with a fuel injection valve 34 that injects fuel into the intake port 16.

  Next, the structure of the impulse valve 32 will be described with reference to FIGS.

  The impulse valve 32 includes a valve housing 41 sandwiched between the intake passage member 31 and the intake pipe 33, and a first intake passage 33 a formed in the intake pipe 33 and a second intake passage 41 a formed in the valve housing 41. The third intake passage 31a formed in the intake passage member 31 is connected in series.

  The valve body 42 housed inside the valve housing 41 is provided integrally with the cylindrical portion 43, a short cylindrical cylindrical portion 43, a pair of rotating shafts 44 and 45 extending in a direction away from the cylindrical portion 43, and the cylindrical portion 43. And a thin disk-shaped disk portion 46 formed. An opening 43 a having a circular cross section passes through the cylindrical portion 43, and an annular first seal surface 46 a constituting a part of a spherical surface is formed on the outer periphery of the disc portion 46.

  The pair of rotating shafts 44 and 45 are disposed on an axis L2 orthogonal to the axis L1 of the second intake passage 41a. One rotating shaft 44 is rotatably supported by the valve housing 41 via a ball bearing 47, The other rotary shaft 45 is rotatably supported by the valve housing 41 via a ball bearing 48 and a seal member 49 and is connected to an electromagnetic actuator 50 fixed to the valve housing 41.

  An annular seat ring 51 is attached to a step portion 41 b formed at the downstream end of the valve housing 41 coupled to the intake passage member 31. The seat ring 51 includes a partially spherical and annular second seal surface 51a on which the first seal surface 46a of the valve body 42 can slide and seat, and an opening having a circular cross section that penetrates the inner periphery of the second seal surface 51a. 51b. The valve housing 41 is integrally formed with an annular regulating member 41c that can abut on the upstream end surface of the seat ring 51.

  An O-ring 52 is attached to an annular groove formed so as to surround the third intake passage 31 a at the upstream end of the intake passage member 31, and the seat ring 51 is directed toward the valve body 42 by the urging force of the O-ring 52. Be energized. An O-ring 53 is mounted in an annular groove formed on the outer periphery of the seat ring 51, and the seat ring 51 is slidably brought into contact with the step portion 41 b of the valve housing 41 via the O-ring 53.

  A crankshaft 54 is fixed to the tip of a rotating shaft 45 that penetrates the seal member 49 and protrudes to the outside of the valve housing 41, and a connecting rod 56 that is slidably supported by a bearing 55 provided in the valve housing 41. The left end and the tip of the crankshaft 54 are connected by a link 57.

  The electromagnetic actuator 50 includes a stacked first housing 61, second housing 62, third housing 63, and fourth housing 64, and the first housing 61 is fixed to the valve housing 41. First and second electromagnets 65 and 66 are accommodated at both ends of the second housing 62, and a drive rod 69 is slidably fitted to bearings 67 and 68 provided in the center of the first and second electromagnets 65 and 66. Match. An armature 70 fixed at the center of the drive rod 69 is disposed in a space formed between the first and second electromagnets 65 and 66, and when the armature 70 is attracted to the first electromagnet 65, the drive rod 69 moves leftward. When the armature 70 is attracted to the second electromagnet 66, the drive rod 69 moves to the right.

  A first spring 72 is disposed between a spring seat 71 provided on the right end side of the connecting rod 56 and the valve housing 41, and the connecting rod 56 is urged rightward by the elastic force of the first spring 72. The A second spring 75 is disposed between a spring seat 73 provided on the right end side of the drive rod 69 and a cap 74 that closes the opening of the fourth housing 64, and the elastic force of the second spring 75 is used. The drive rod 69 is biased leftward.

  The connecting rod 56 and the drive rod 69 are coaxially opposed inside the first housing 61, and the hydraulic shock absorbing mechanism 76 is disposed there. As shown in an enlarged view in FIG. 7, the hydraulic shock-absorbing mechanism 76 includes a cylinder 77 formed in the first housing 61 and a piston 78 that is slidably fitted to the cylinder 77. The right end of the connecting rod 56 is fitted into the left recess 78 a formed, and the left end of the drive rod 69 is fitted through the shim 79 into the right recess 78 b. At this time, the connecting rod 56 and the drive rod 69 are urged toward each other by the first and second springs 72 and 75, and therefore the positional relationship between the connecting rod 56, the drive rod 69 and the piston 78 is always constant. Maintained.

  A pressure chamber 80 formed in the first housing 61 so as to surround the outer periphery of the drive rod 69 communicates with a hydraulic pump (not shown) via a first supply oil passage 81, a check valve 82 and a second supply oil passage 83. At the same time, it communicates with an oil pan (not shown) via a discharge passage 84. When the piston 78 moves to the right to close the discharge passage 84, the pressure chamber 80 and the discharge passage 84 are slightly communicated with each other through an orifice 78c formed in the piston 78.

  Next, the operation of the embodiment having the above configuration will be described.

  FIG. 9 shows an operation region of the engine E using the engine speed and the engine load (net average effective pressure BMEP) as parameters, and the low rotation high load region A is a normal operation region of the impulse valve 32. In the low rotation high load region A, the impulse valve 32 is controlled at the valve opening timing and the valve closing timing determined from the engine speed and the throttle opening.

  FIG. 10 shows that the opening timing (opening start) and closing timing (closing end) of the impulse valve 32 are the intake pipe length (distance from the impulse valve 32 to the upstream surge tank), the engine speed, and the opening / closing time. It shows how it changes according to. The opening time of the impulse valve 32 is the time from the beginning of opening to the end of opening, and the closing time is the time from the beginning of closing to the end of closing, and is determined by the operating speed of the electromagnetic actuator 50. The solid line in the figure corresponds to an intake pipe length of 615 mm and an open / close time of 3.3 ms, the broken line corresponds to an intake pipe length of 315 mm and an open / close time of 3.3 ms, and the chain line represents an open / close time of an intake pipe length of 315 mm. The closing time corresponds to 0 ms.

  As can be seen from the figure, the impulse valve 32 is controlled to open in the middle of the intake stroke and to close in the initial stage of the compression stroke so that the intake charging efficiency is maximized. As the engine speed increases, the valve opening timing is gradually advanced and the valve closing timing is gradually retarded. During this time, the opening timing and closing timing of the impulse valve 32 also depend on the intake pipe length and the time required for opening and closing the impulse valve 32.

  That is, the opening angle of the impulse valve 32 is the time required for the pressure wave to reciprocate in the intake pipe. Therefore, the longer the intake pipe, the larger the open angle, and the shorter the intake pipe, the smaller the open angle. Therefore, if the intake pipe is shortened, the opening timing can be delayed, and a supercharging effect can be obtained up to a higher rotation speed, but an impulse valve 32 that can be opened and closed in a shorter time is required.

  When changing the valve opening timing and closing timing of the impulse valve 32, the limit on the advance side of the valve opening timing is determined according to the intake negative pressure, and the limit on the retard side of the valve closing timing is the intake valve. 18 and 18 are determined according to the valve opening timing.

  As shown in FIG. 11, in the first half of the intake stroke, the piston 13 descends while the intake valve 18 is opened, so that the third intake passage 31a, the intake port 16 and the combustion downstream of the valve body 42 closed. A large negative pressure is generated in the chamber 15. When the valve body 42 opens in the middle of the intake stroke, the negative pressure causes the first intake passage 33a and the second intake passage 41a upstream from the valve body 42 toward the combustion chamber 15 in the latter half of the subsequent intake stroke. Intake flows at high speed.

  The negative pressure wave generated at that time is transmitted to the upstream side of the intake passage and reflected to the surge tank, and the reflected wave is transmitted to the combustion chamber 15 to close the valve body 42 at the peak of the positive pressure generated. , The charging efficiency of intake can be greatly increased. When the intake valve 18 is closed, the positive pressure in the space defined between the intake valve 18 and the closed valve body 42 is confined. Accordingly, the combustion chamber 15 can be scavenged with a positive pressure confined in the space during the valve overlap period in which the end of the valve opening period of the next exhaust valve 19 overlaps the initial period of the valve opening period of the intake valve 18. .

  2 and 4, when the armature 70 of the electromagnetic actuator 50 is attracted to the first electromagnet 65, the first spring 72 is contracted and the second spring 75 is extended while the drive rod 69, piston 78, and The connecting rod 56 moves to the left and presses the crankshaft 54 via the link 57. As a result, the valve body 42 of the impulse valve 32 rotates in one direction together with the rotation shafts 44 and 45, the axis L3 of the disc portion 46 is orthogonal to the axis L1 of the second intake passage 41a, and the axis of the cylindrical portion 43 When L4 matches, the impulse valve 32 opens.

  As shown in FIGS. 3 and 5, when the armature 70 of the electromagnetic actuator 50 is attracted to the second electromagnet 66, the second spring 75 is contracted and the first spring 72 is extended, and the drive rod 69, piston 78, and The connecting rod 56 moves to the right and pulls the crankshaft 54 via the link 57. As a result, the valve body 42 of the impulse valve 32 rotates in the reverse direction together with the rotary shafts 44 and 45, the axis L3 of the disc portion 46 coincides with the axis L1 of the second intake passage 41a, and the axis of the cylindrical portion 43 The impulse valve 32 is closed when L4 is orthogonal.

  When the impulse valve 32 is in the open state, as shown in FIG. 8A, the connecting rod 56 and the drive rod 69 are in the left movement position, and the piston 78 of the hydraulic shock absorber 76 opens the discharge oil passage 84. The hydraulic oil supplied from the first supply oil passage 81 passes through the check valve 82 and is discharged from there through the second supply oil passage 83 and the pressure chamber 80 to the discharge oil passage 84.

  When the second electromagnet 66 is excited to close the impulse valve 32, the armature 70 is attracted to the second electromagnet 66 and the drive rod 69 moves right against the elastic force of the second spring 75, and the connecting rod 56 is moved to the right by the elastic force of the first spring 72 to cause the piston 78 to follow the drive rod 69. As a result, as shown in FIG. 8 (B), the piston 78 that moves to the right gradually closes the discharge passage 84, whereby the pressure in the pressure chamber 80 increases, the opening of the check valve 82 decreases, and the piston 78 A braking force for the right movement is generated, and the right moving speed of the connecting rod 56 and the drive rod 69, that is, the closing speed of the impulse valve 32 is reduced.

  When the impulse valve 32 is about to close completely, the piston 78 completely closes the discharge passage 84 so that the pressure chamber 80 and the discharge passage 84 are connected to the orifice of the piston 78 as shown in FIG. The pressure in the pressure chamber 80 increases suddenly only by 78c, and at the same time the check valve 32 closes, a strong braking force against the right movement of the piston 78 is generated, and the impulse valve 32 slowly moves to the closed position. Sit down. Thereby, the impact at the time of seating of the impulse valve 32 can be prevented, and the generation of noise and the deterioration of durability can be prevented.

  In this way, when the armature 70 is attracted to the second electromagnet 66, the piston 78 and the piston 78 and the second seal surface 51a of the seat ring 51 are correctly seated on the first seal surface 46a of the valve body 42 of the impulse valve 32. The thickness of the shim 79 disposed between the drive rods 69 is adjusted. The shim 79 can be integrated with the piston 78.

  When the impulse valve 32 is opened, the piston 78 moves to the left to increase the volume of the pressure chamber 80. However, since the check valve 82 is opened, the hydraulic oil freely flows into the pressure chamber 80, A braking force is not generated in the left movement of the piston 78.

  In the low-rotation partial load region B of the engine E shown in FIG. 9, conventionally, one intake of the two intake ports is opened and the other is closed using a one-valve stop mechanism, so that the intake air introduced into the combustion chamber 15 is reduced. A swirl was generated to improve fluidity and improve the combustion state of the air-fuel mixture to reduce fuel consumption.

  On the other hand, in the present embodiment, the combustion state of the air-fuel mixture in the low rotation partial load region B is improved by controlling the operation of the impulse valve 32 without using special means such as a one-valve pause mechanism. It is like that.

  FIG. 12 is a graph showing the relationship between the crank angle and the opening degree of the impulse valve 32 in the low rotation partial load region B of the engine. The characteristic of the “impulse valve operation” indicated by the broken line is the same as the opening degree of the impulse valve 32 in the low rotation high load region A described with reference to FIG. 9, and the intake air amount at this time is controlled by the throttle valve. In addition, the characteristic of “impulse valve early closing” indicated by a one-dot chain line is an advance of the characteristic of “impulse valve operation” to a position where the pumping loss is minimized, and the valve opening period is extended. The intake air amount is controlled by the timing of early closing.

  FIG. 13 is a graph showing the relationship between the indicated average effective pressure IMEP and the fluctuation rate of the indicated average effective pressure in the low rotation partial load region B of the engine E. The solid line indicates the state in which the impulse valve 32 is inoperative, and the broken line indicates The impulse valve 32 is in the activated state (see the broken line in FIG. 12), and the alternate long and short dash line is the state in which the impulse valve 32 is closed early (see the dashed line in FIG. 12). As is apparent from this figure, when the impulse valve 32 is operated (see the broken line) in the same manner as in the low rotation and high load region A (see the broken line), the effect of increasing the flow velocity of the intake air is greater than when the impulse valve 32 is not activated (see the solid line). Thus, the combustion stability is good (that is, the Pmi fluctuation rate is small). On the other hand, when the impulse valve 32 is closed earlier than in the case of the low rotation and high load region A (see the alternate long and short dash line), the intake air flow velocity is lowered and the temperature in the cylinder is lowered compared to the case where the impulse valve 32 is not operated (see the solid line). Due to the influence of fuel liquefaction, combustion stability is poor (that is, the Pmi fluctuation rate is large).

  FIG. 14 is a graph showing the relationship between the indicated mean effective pressure IMEP and the indicated fuel consumption rate ISFC in the low-rotation partial load region B of the engine E, where the solid line indicates the state in which the impulse valve 32 is inoperative, and the broken line indicates the impulse valve. Reference numeral 32 denotes an operating state (see the broken line in FIG. 12), and alternate long and short dash lines indicate a state in which the impulse valve 32 closes quickly (see the dashed-dotted line in FIG. 12). As is apparent from this figure, when the impulse valve 32 is operated (see the broken line) as in the low rotation high load region A (see the broken line), the indicated fuel consumption rate ISFC is greater than when the impulse valve 32 is not activated (see the solid line). When the impulse valve 32 is closed earlier than in the case of the low rotation high load region A (see the one-dot chain line), the illustrated fuel consumption rate ISFC is poorer than when the impulse valve 32 is not operated (see the solid line). become.

  That is, when the impulse valve 32 is operated in the low rotation partial load region B of the engine E, the combustion state is improved and the illustrated fuel consumption rate ISFC is improved, and when the impulse valve 32 is quickly closed, the combustion state is deteriorated. Thus, it can be seen that the illustrated fuel consumption rate ISFC is poor.

  FIG. 15 is a graph showing the relationship between the indicated mean effective pressure IMEP and the net fuel consumption rate BSFC in the low rotation partial load region B of the engine E, where the solid line indicates a state in which the impulse valve 32 is inoperative, and the broken line indicates an impulse valve. Reference numeral 32 denotes an operating state (see the broken line in FIG. 12), and alternate long and short dash lines indicate a state in which the impulse valve 32 closes quickly (see the dashed-dotted line in FIG. 12). As is apparent from this figure, when the impulse valve 32 is operated (see the broken line) as in the low rotation high load region A (see the broken line), the net fuel consumption rate BSFC is smaller than when the impulse valve 32 is not operated (see the solid line). If the impulse valve 32 is closed earlier than in the case of the low rotation high load region A (see the dashed line), the net fuel consumption rate BSFC is better than when the impulse valve 32 is not operated (see the solid line). become.

  FIG. 16 is a graph showing the relationship between the indicated mean effective pressure IMEP and the mean effective pump loss PMEP in the low rotation partial load region B of the engine E, where the solid line indicates the state in which the impulse valve 32 is inoperative, and the broken line indicates the impulse valve. Reference numeral 32 denotes an operating state (see the broken line in FIG. 12), and alternate long and short dash lines indicate a state in which the impulse valve 32 closes quickly (see the dashed-dotted line in FIG. 12). As is apparent from this figure, when the impulse valve 32 is operated as in the low rotation high load region A (see the broken line), the pumping loss is increased as compared with the case where the impulse valve 32 is not operated (see the solid line). When the impulse valve 32 is closed earlier than in the case of the low rotation and high load region A (see the one-dot chain line), the pumping loss is reduced compared to when the impulse valve 32 is not operated (see the solid line).

  Thus, although the illustrated fuel consumption rate ISFC is improved when the impulse valve 32 is operated at normal timing, the net fuel consumption rate BSFC is deteriorated in the combustion chamber 15 and the intake port 16. This is due to an increase in pumping loss due to an increase in negative pressure. On the other hand, when the impulse valve 32 is quickly closed, the pumping loss is reduced, and the net fuel consumption rate BSFC is improved despite the deterioration of the illustrated fuel consumption rate ISFC.

  From the above, in the low-rotation partial load region B, both the improvement effect of the combustion state by operating the impulse valve 32 at normal timing and the reduction effect of the pumping loss by quickly closing the impulse valve 32 are achieved. In order to reduce the fuel consumption as much as possible, as shown in FIG. 17, the valve opening characteristic of the impulse valve 32 in the low rotation partial load region B is different from the valve opening characteristic of the impulse valve 32 in the low rotation high load region A. The valve opening characteristic may be advanced, and the opening angle may be smaller than that shown in FIG. As a result, the pumping loss can be reduced as compared with the case where the impulse valve 32 is inoperative, as in the case shown by the two-dot chain line in FIG.

  That is, the characteristics of the one-dot chain line in FIG. 12 are those in which the valve opening characteristic of the impulse valve 32 is set so that the pumping loss is minimized, but by setting the opening angle to be smaller than that, the impulse valve 32 is The effect of improving the combustion state by operating and the effect of reducing the pumping loss by quickly closing the impulse valve 32 can be well balanced, and the net fuel consumption rate BSFC can be minimized.

  As described above, in the low rotation partial load region B of the engine E, the impulse valve 32 is operated more advanced than the low rotation high load region A, so that it is complicated and expensive like a one-valve pause mechanism. It is possible to effectively reduce the fuel consumption of the engine E without using any means.

  Note that, in the high rotation region C of the engine E in FIG. 9, the impulse valve 32 is held in the open state shown in FIGS. 2 and 4.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the impulse valve 32 made of a ball valve is exemplified, but an impulse valve having an arbitrary structure such as a butterfly valve, a flap valve, or a poppet valve can be employed.

Cross section of engine cylinder head and impulse valve Enlarged view of the main part of Fig. 1 (Impulse valve open state) The figure which shows the valve closing state of the impulse valve corresponding to FIG. 4 direction view of FIG. 5 direction arrow view of FIG. Perspective view of valve body 2 is an enlarged view of the main part of FIG. Action explanatory diagram of hydraulic shock absorber Graph showing the operating range of the engine that operates the impulse valve A graph showing the relationship between engine speed, intake pipe length, and impulse valve opening / closing timing Graph showing the relationship between crank angle and impulse valve opening / closing timing A graph showing the relationship between the crank angle and the opening of the impulse valve in the low rotation partial load region of the engine A graph showing the relationship between the indicated mean effective pressure IMEP and the indicated mean effective pressure variation rate in the low engine speed partial load region of the engine A graph showing the relationship between the indicated mean effective pressure IMEP and the indicated fuel consumption rate ISFC in the low engine speed partial load region of the engine A graph showing the relationship between the indicated mean effective pressure IMEP and the net fuel consumption rate BSFC in the engine low load partial load region A graph showing the relationship between the indicated mean effective pressure IMEP and the mean effective pump loss PMEP in the low engine speed partial load region of the engine Graph showing the relationship between crank angle and intake flow coefficient

Explanation of symbols

A Low engine speed and high load area B Low engine speed and partial load area E Engine 15 Combustion chamber 16 Intake port 32 Impulse valve

Claims (1)

In an engine intake control device that opens and closes an intake port (16) connected to a combustion chamber (15) by an impulse valve (32) in a low rotation high load region (A) of the engine (E) to exert a supercharging effect,
An engine characterized in that the opening / closing timing of the impulse valve (32) in the low rotation partial load region (B) of the engine (E) is advanced with respect to the opening / closing timing in the low rotation high load region (A). Intake control device.

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