JP4546289B2 - Variable valve engine for vehicles - Google Patents

Description

  According to the present invention, an intake valve is disposed in a cylinder head of an engine body disposed behind a radiator fan so that the intake valve can be opened and closed. The present invention relates to a variable valve engine for a vehicle in which an intake system having no throttle valve is connected to an intake port of the cylinder head.

A variable valve engine in which a throttle valve is not interposed in the intake system by adjusting the intake air amount by controlling the opening and closing of the intake valve is already known from Patent Document 1, When the variable valve engine is mounted on an automobile, the engine body is disposed behind the radiator fan.
Japanese Patent No. 3494049

  In the variable valve engine as disclosed in the above-mentioned Patent Document 1, the most difficult metering is during no-load operation, that is, idling operation, and in the idling operation state, the engine-specific friction and engine work compete. Therefore, when the intake air amount is misaligned, the antagonistic point is deviated and the idling engine speed fluctuates. In order to avoid the fluctuation of the idling speed, the intake air amount must be accurately adjusted. On the other hand, the actuator that controls the opening and closing of the intake valve is easily affected by heat and should be placed at a position that is not easily affected by heat, but is placed behind the radiator fan when mounted on a car. Since the actuator is attached to the cylinder head of the engine body, and the back wind from the radiator fan is heated by heat exchange, there is a possibility that the back wind will affect the actuator. In particular, since a lot of cooling by running cooling air cannot be expected during idle operation, there are many opportunities for the radiator fan to rotate, and it is necessary to prevent the heat effect from the back wind from the radiator fan during such idle operation from affecting the actuator. is there.

  The present invention has been made in view of such circumstances, and controls the opening and closing of the intake valve by controlling the opening and closing of the intake valve to regulate the intake amount so that the throttle valve is not interposed in the intake system. It is an object of the present invention to provide a variable valve engine for a vehicle in which the actuator is not affected by the heat caused by the back wind from the radiator fan.

In order to achieve the above object, according to the first aspect of the present invention, an intake valve is disposed in a cylinder head of an engine main body disposed behind a radiator fan so as to be capable of opening and closing, and the intake air amount is regulated. In a variable valve engine for a vehicle in which an actuator for controlling opening / closing of an intake valve is attached to the engine body, and an intake system having no throttle valve is connected to an intake port of the cylinder head, between the radiator fan and the actuator Is characterized in that an intake chamber is provided which also serves as a back wind protection means for preventing the back wind from the radiator fan from directly hitting the actuator and constitutes a part of the intake system .

The invention according to claim 2, in addition to the configuration of the invention according to claim 1, in front of the engine body mounted on a vehicle and along a crank axis in the lateral direction, deflects the back wind on one left or right Thus, the radiator fan is arranged, and the actuator is attached to an end wall on the opposite side to the back wind deflection direction from the radiator fan in the left and right end walls of the engine body.

Further the third aspect of the present invention, in addition to the configuration of the invention according to claim 2, upstream open end of the air intake duct in which the intake system comprises an upstream end, a back wind deflecting direction from the radiator fan on the opposite side It is arranged on the side of the engine body.

  According to the first aspect of the present invention, the back wind from the radiator fan can be prevented from directly hitting the actuator by the back wind protection means, and the back wind from the radiator fan can be obtained even during idle operation where the radiator fan often rotates. The idling operation can be stabilized in such a manner that the thermal effect due to the above does not reach the actuator.

Moreover, since the air intake chamber also serves as the back air defenses, dedicated members for the back wind protection is unnecessary, while avoiding an increase in the number of parts, thereby simplifying the structure.

According to the second aspect of the invention, and less back airflow from the radiator fan towards the actuator side, it is possible to stabilize the idling.

Furthermore, according to the third aspect of the present invention, it is possible to achieve both improvement in engine output and idle stability by preventing the back wind from the radiator fan from entering the intake duct as much as possible.

  Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  FIGS. 1 to 17 show a first embodiment of the present invention. FIG. 1 is a side view of a variable valve engine in a vehicle-mounted state, FIG. 2 is a view taken along arrow 2 in FIG. 1, and FIG. 4 is a view taken along the line 4-4 in FIG. 3, FIG. 5 is a longitudinal side view of the valve operating device for the intake valve, and FIG. 6 is an exploded perspective view of the valve operating device for the intake valve. 7 is a longitudinal side view of the actuator, FIG. 8 is a plan view of the intake chamber and the upstream side intake pipe, FIG. 9 is a cross-sectional view taken along line 9-9 of FIG. 8, FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. Is a sectional view taken along the line 11-11 in FIG. 8, FIG. 12 is a plan view of the second chamber half viewed from the direction of the arrow 12-12 in FIG. 11, and FIG. 13 is a plan view of the reinforcing plate and the downstream intake pipe. 14 is an enlarged cross-sectional view taken along the line 14-14 in FIG. 12, FIG. 15 is a diagram showing a change in volumetric efficiency due to the ratio of the intake chamber volume to the total displacement, and FIG. Graph showing the degree of variation in the air-fuel ratio by the ratio of the intake chamber volume for, FIG. 17 is a graph showing changes in intake sound by the ratio of the intake chamber volume to the total emissions.

  First, in FIGS. 1 to 4, a plurality of cylinders, for example, a four-cylinder engine body 22 in which the axis C of the crankshaft 21 is arranged in the width direction of the vehicle is mounted on the front portion of the vehicle. The engine body 22 is provided side by side in a cylinder arrangement direction 23 parallel to the axis C. In front of the engine body 22, a radiator 24 for cooling the coolant that has been heated by cooling the engine body 22 and a condenser 25 of an air conditioner mounted on the vehicle are arranged in the cylinder arrangement direction 23. Arranged side by side, a radiator fan 26 and a condenser fan 27 are attached to the rear of the radiator 24 and the condenser 25.

  The engine body 22 includes a crankcase 28 that rotatably supports the crankshaft 21, a cylinder block 29 that is coupled to the crankcase 28, a cylinder head 30 that is coupled to the cylinder block 29, and a cylinder head 30. And a transmission case 32 that houses a transmission at the left end of the crankcase 28 in a state of facing forward in the traveling direction of the vehicle, on the left side of the engine body 22 and the transmission case. They are combined so as to form an empty space above 32.

  One side wall 30a (see FIG. 1) facing the front side of the cylinder head 30 is provided with intake ports 33 for each cylinder, and an intake system 34 is connected to the intake ports 33. The other side wall 30b (see FIG. 1) facing the rear side of the cylinder head 30 is provided with exhaust ports 35 for the respective cylinders. The exhaust manifold 37 to be covered is connected.

  5 and 6, the cylinder head 30 is provided with a pair of intake valves 38 for each intake port 33 so as to be able to open and close. The intake side motion for driving the intake valves 38 to open and close is provided. The valve device 39 swings in accordance with the intake side camshaft 41 having the intake side valve cam 40 for each cylinder and the intake side valve cam 40 and is common to a pair of intake valves 38 for each cylinder. Each cylinder is provided with an intake side rocker arm 42 that is linked and connected to each other, and a variable lift mechanism 43 that continuously changes the valve opening lift amount among the operating characteristics of the intake valves 38.

  Upper holders 44 are fastened to the cylinder head 30 so as to be arranged on both sides of each cylinder, and a cap 45 that rotatably supports the intake camshaft 41 in cooperation with the upper holders 44. Are fastened to the upper surface of the upper holder 44.

  One end portion of the intake side rocker arm 42 is provided with a valve connecting portion 42a into which tappet screws 46 abutting from above on the upper ends of the stems 38a of the pair of intake valves 38 are screwed so that the advance / retreat position can be adjusted. The other end portion of the intake side rocker arm 42 is provided with a first support portion 42b and a second support portion 42c disposed below the first support portion 42b so as to be connected to each other. The portions 42b and 42c are formed in a substantially U shape that opens on the opposite side to the intake valves 38.

  A roller 47 that is in rolling contact with the intake side valve cam 40 of the intake side camshaft 41 is pivotally supported on the first support portion 42 b of the intake side rocker arm 42 via a first connecting shaft 48 and a needle bearing 49. The roller 47 is disposed so as to be sandwiched between first support portions 42b having a substantially U shape.

  The variable lift mechanism 43 has a first link arm whose one end is rotatably connected to the first support portion 42 b of the intake side rocker arm 42 and whose other end is rotatably supported by the intake side rocker shaft 50. 51, a second link arm 52 whose one end is rotatably connected to the second support portion 42c of the intake side rocker arm 42, and a movable support that rotatably supports the other end of the second link arm 52. A shaft 53 and a control shaft 54 coupled to the movable support shaft 53 are provided so that the movable support shaft 53 can be angularly displaced about an axis parallel to the axis.

  One end portion of the first link arm 51 is formed in a substantially U shape so as to sandwich the first support portion 42b of the intake side rocker arm 42 from both sides, and a first connection that pivotally supports the roller 47 on the intake side rocker arm 42. The shaft 48 is rotatably connected to the first support portion 42b. The intake side rocker shaft 50 that rotatably supports the other end of the first link arm 51 is supported by the upper holder 44.

  One end portion of the second link arm 52 disposed below the first link arm 51 is disposed so as to be sandwiched between the second support portions 42 c of the intake side rocker arm 42, and is second supported via the second connecting shaft 55. The part 42c is rotatably connected.

  The two intake valves 38 are spring-biased in the valve closing direction by a valve spring (not shown), and the two intake valves 38... That are spring-biased in the valve closing direction are opened by the intake side rocker arm 42 in the valve opening direction. The roller 47 of the intake-side rocker arm 42 is in contact with the intake-side valve cam 40 by the spring biasing force of the valve spring while the intake valve 38 is in the closed state. The spring biasing force of the spring does not act on the intake side rocker arm 42, and the roller 47 is separated from the intake side valve cam 40, and the control accuracy of the valve lift amount when the intake valves 38 are minutely opened decreases. There is a possibility that. Therefore, the rocker arm biasing spring 56 different from the valve spring biases the intake-side rocker arm 42 in a direction in which the roller 47 is brought into contact with the intake-side valve cam 40.

  The control shaft 54 is a single unit common to a plurality of cylinders arranged in a row, and the webs 54a... Disposed on both sides of the intake side rocker arm 42 and the journal portion that is perpendicular to the outer surface of the base end of both webs 54a. 54b... And a connecting portion 54c that connects the two webs 54a... Are formed in an integral crank shape, and the movable support shaft 53 is connected to the two webs 54a. 54. Moreover, the journal portions 54b are rotatably supported by the upper holders 44 and lower holders 57 fastened to the lower surfaces of the upper holders 44.

  By the way, the second connecting shaft 55 that connects the second link arm 52 to the intake side rocker arm 42 when the intake valves 38 are closed is coaxial with the journal portion 54b of the control shaft 54, and the control shaft 54 Oscillates around the axis of the journal portion 54b..., The movable support shaft 53 moves on an arc centered on the axis of the journal portion 54b.

  When the control shaft 54 rotates in the direction in which the movable support shaft 53 descends and the roller 47 is pressed by the intake side valve cam 40 of the intake side camshaft 41, the intake side rocker shaft 50, the first connecting shaft 48, The four-bar link connecting the second connecting shaft 55 and the movable support shaft 53 is deformed, the intake side rocker arm 42 swings downward, the tappet screws 46... Press the stem 38 a. Open the valve with a low lift.

  When the control shaft 54 is rotated in the direction in which the movable support shaft 53 is raised and the roller 47 is pressed by the intake side valve cam 40 of the intake side camshaft 41, the four-bar link is deformed and the intake side rocker arm is deformed. 42 swings downward, the tappet screws 46 press the stems 38a of the intake valves 38, and the intake valves 38 open with high lift.

  Referring to FIG. 7 as well, one end portion of the control shaft 54 along the cylinder arrangement direction 23, that is, the journal portion 54b on one end side along the cylinder arrangement direction 23 of the plurality of journal portions 54b provided in the control shaft 54 is The engine body 22 is inserted into the storage box 61 of the actuator 60 attached to the outer surface of the left end wall of the cylinder head 30.

  The actuator 60 includes an electric motor 62 and a power transmission means 63 that transmits the rotational power of the electric motor 62 to one end of the journal portion 54 b that has entered the storage box 61.

  The storage box 61 is a box main body 64 integrally having a case portion 64a formed in a box shape with the side opposite to the cylinder head 30 open, and a support wall portion 64b extending downwardly connected to one side wall of the case portion 64a. And a box-shaped case 65 fastened to the box main body 64 so as to cover the one side wall and the support wall 64b from the outside, and the box main body 64 so as to close the open end of the case portion 64a. The box main body 64 and the lid member 66 are attached to the cylinder head 30 by fastening together.

  The electric motor 62 is disposed below the case portion 64 a and is attached to the support wall portion 64 b. In the storage box 61, the rotational power of the electric motor 62 is journal portion 54 b which is one end portion of the control shaft 54. The power transmission means 63 for transmitting to is accommodated.

  The power transmission means 63 includes a control arm 68 whose base end is fixed to one end of the journal portion 54b that has entered the storage box 61 via a key 67, and an axis that is perpendicular to the axis of the journal portion 54b. A screw shaft 69 to be arranged, a nut member 70 screwed into the screw shaft 69, one end connected to the nut member 70 by a pin 71, and the other end connected to the control arm 68 via a pair of pins 72. And a reduction gear mechanism 74 provided between the screw shaft 69 and the electric motor 62.

  The control arm 68 is housed in the case portion 64a of the housing box 61, and has a screw shaft that has an axis extending parallel to the electric motor 62 and extending in the lateral direction, and is mostly contained in the case portion 64a. One end of 69 projects from one side wall of the case portion 64a.

  The reduction gear mechanism 74 is provided between the output shaft 62a of the electric motor 62 and the screw shaft 69 and is accommodated in the case 65. The drive gear 75 is fixed to the output shaft 62a, and the drive gear 75 is connected to the drive gear 75. And a driven gear 76 that meshes with and is fixed to one end of the screw shaft 69.

  In such an intake side valve operating device 39, the lift amount of the intake valves 38 can be changed steplessly by displacing the movable support shaft 53 steplessly by the operation of the electric motor 62. It is possible to adjust the intake air amount with the intake valves 38... And it becomes unnecessary to provide a throttle valve in the intake system 34.

  1 to 4 again, the intake system 34 is disposed between the radiator fan 26 and the condenser fan 27 and the engine body 22 so that the intake chamber 80 facing the one side wall 30a of the cylinder head 30 is located in the middle. Part.

  8 to 11, the intake chamber 80 includes a first chamber half 81 having a bowl shape opened downward and a second chamber half 82 having a bowl shape opened upward. The first and second chamber halves 81 and 82 are made of a light alloy such as an aluminum alloy.

  The second chamber half 82 is formed in a deep bowl shape, whereas the first chamber half 81 is formed in a shallow bowl shape, and the first and second chamber halves 81 and 82 Due to the difference in shape, the rigidity of the first chamber half 81 itself is weaker than the rigidity of the second chamber half 82 itself.

  In addition, a pair of support legs 83, 83 project integrally from the bottom of the second chamber half 82 so as to extend downward, and these support legs 83 are attached to the crankcase 28. The bracket 84 (see FIG. 4) is supported via elastic members 85.

  On the upper surface of the first chamber half 81 constituting a part of the intake chamber 80, a plurality (four in this embodiment) individually corresponding to the intake ports 33 provided on one side wall 30a of the cylinder head 30 are provided. The connection cylinders 86 are integrally formed so as to protrude slightly upward while forming the connection ports 87 that are open upward, and the intake chamber 80 extends along the cylinder arrangement direction 23 of the engine body 22. The connection ports 37 are arranged at positions shifted from the intake ports 33 to the one side (in this embodiment, the left side when facing the front of the vehicle) and more than one end of the engine body 22 along the cylinder arrangement direction 23. It arrange | positions so that one end may protrude to the side.

  The volume of the intake chamber 80 is set so as to have a ratio equal to or greater than a predetermined value with respect to the total displacement of the engine. For example, the predetermined value is set to 1.7 so as to satisfy all of the engine output improvement, the silence of the intake sound, and the air-fuel ratio controllability.

  The upstream ends of downstream intake pipes 88 extending to the intake ports 33 of the cylinder head 30 are connected to the connection ports 37, and the downstream intake pipes 88 are directed downward. It is formed in the same shape with an open substantially U shape. Moreover, the downstream side intake pipes 88 are arranged so as to cross obliquely with respect to the cylinder arrangement direction 23 in a plan view.

  On the other hand, a flange 89 common to each intake port 33 is fastened to one side wall 30a of the cylinder head 30, and a connection pipe coupled to the flange 89 individually corresponding to each intake port 33. 90 are connected to downstream ends of the downstream side intake pipes 88 through connectors 91. As a result, the downstream ends of the downstream side intake pipes 88 are individually connected to the intake ports 33. Moreover, as shown in FIG. 3, the width D1 of the intake chamber 80 along the cylinder arrangement direction 23 is set larger than the width D2 of the flange.

  An intake chamber 80 and a generator 92 arranged on the other side of the intake chamber 80 along the cylinder arrangement direction 23 are arranged side by side in the cylinder arrangement direction 23 at a position facing the one side wall 30 a of the cylinder head 30. The downstream side intake pipes 88 are arranged to incline toward the side away from the generator 92 toward the intake chamber 80 side.

  Further, the intake chamber 80 accommodates a plurality of upstream intake pipes 93 that are individually connected to the upstream ends of the downstream intake pipes 88... The side intake pipes 88 are formed so as to bend in a substantially U shape within a plane that obliquely intersects the cylinder arrangement direction 23 at an acute angle with respect to the cylinder arrangement direction 23.

  With particular attention to FIG. 9, in the connection cylinder portion 86 provided in the first chamber half 81, a connection port 87 at the upper end and a first step portion 94 facing upward are formed between the connection port 87. Thus, a small diameter hole 95 having a smaller diameter than the connection port 87 and a second step portion 96 facing downward are formed between the lower end of the small diameter hole 95 to form a diameter larger than that of the small diameter hole 95. When the small diameter end is connected to the lower end of the first fitting hole 97 and the first fitting hole 97, the taper surface 98 that becomes larger in diameter toward the lower side and the large diameter end of the tapered surface 98 downward. A third fitting portion 99 that faces the second fitting hole 100 connected to the large diameter end of the tapered surface 98 is provided coaxially.

  The upstream ends of the downstream side intake pipes 88 are welded to the connection cylinder portion 96 over the entire circumference in a state of being fitted to the connection port 97 until they are in contact with the first step portion 94. On the other hand, the flange member 101 is welded to the downstream end portion of the upstream side intake pipe 93... So as to project outward in the radial direction, and the downstream end of the upstream side intake pipe 93. The outer periphery of the flange member 101 is fitted into the second fitting hole 100 when fitted into the first fitting hole 97 until it abuts. In addition, an O-ring 102 held by the flange member 101 is attached to the outer periphery of the downstream end of the upstream side intake pipe 93. The O-ring 102 is connected to the outer periphery of the downstream end of the upstream side intake pipe 93. By interposing them in between, the connection portions of the upstream side intake pipes 93 to the first chamber half 81 are sealed. In this way, the downstream ends of the upstream intake pipes 93 are connected to the upstream ends of the downstream intake pipes 88 through the first chamber half 81, and the downstream ends of the downstream intake pipes 88 are connected to the intake port 33. Will be connected to ...

  As shown in FIG. 12, insertion holes 105 are provided at a plurality of locations on the outer periphery of the second chamber half 82, and bolts 106 inserted into the insertion holes 105 are used as the first chamber half 81. The first and second chamber halves 81 and 82 are coupled to each other by being screwed to each other. In order to reinforce the coupling portion of the first and second chamber halves 81 and 82. The reinforcing plate 107 is accommodated in the intake chamber 80.

  Referring also to FIG. 13, the intermediate portion of the upstream side intake pipes 93... Penetrates the reinforcing plate 107 and is welded to the reinforcing plate 107. That is, each upstream side intake pipe 93 is supported by the reinforcing plate 107. Moreover, the peripheral edge portion of the reinforcing plate 107 is bent and formed, for example, so as to form a bent portion 107a that bends toward the second chamber half body 82 side.

  At a plurality of locations in the circumferential direction of the reinforcing plate 107, insertion holes 110 are provided for inserting bolts 109 that are screwed into mounting seats 108 provided at a plurality of locations on the peripheral edge of the first chamber half 81. The reinforcing plate 107 is attached to the first chamber half 81 by tightening the bolts 109. In addition, the mounting seats 108 and the insertion holes 110 are a plurality of fastening points for fastening the first and second chamber halves 81 and 82 to each other, that is, a plurality of insertion holes 105 provided in the second chamber half 82. The reinforcing plate 107 is attached to the first chamber half 81 between a plurality of fastening points where the first and second chamber halves 81 and 82 are fastened to each other.

  Referring also to FIG. 14, ribs 111 are integrally provided at a plurality of locations in the circumferential direction of the inner periphery of the second chamber half 82, and the ribs 111. A columnar detachment prevention portion 111a that is close to and faces the head of the bolt 109 for attaching to the half body 81, and a connecting portion 111b that connects the inner periphery of the second chamber half body 82 and the detachment prevention portion 111a. Are integrally provided.

  Further, the reinforcing plate 107 is provided with two notches 112 and 113 that face the upstream opening ends of the upstream side intake pipes 93... And the upstream side intake pipes 93 that are accommodated in the intake chamber 80. The reinforcing plate 107 is formed in a shape that avoids the inhibition of fresh air inflow to the upstream end opening.

  1 to 3 again, an actuator 60 for adjusting the intake air amount by controlling the opening and closing of the intake valves 38 is attached to the cylinder head 30 of the engine body 22 disposed behind the radiator fan 26. However, as shown by the white arrow in FIG. 1, the warm back wind from the radiator fan 26 directly hits the actuator 60 by the intake chamber 80 as a back wind protection means disposed between the radiator fan 26 and the actuator 60. Is blocked.

  In addition, the radiator fan 26 and the condenser fan 27 are configured so as to deflect the back wind to the left or right (in this embodiment, left when the vehicle is viewed from the front) as shown by an arrow 114 in FIG. The actuator 60 is mounted on the end wall on the opposite side to the direction of the back wind deflection from the radiator fan 26 in the left and right end walls of the cylinder head 30 of the engine body 22. It has been.

  Incidentally, the downstream end of the connection duct 120 connected to the air cleaner 118 is connected via a connector 121 to the intake introduction cylinder portion 116 provided integrally with the first chamber half 81 of the intake chamber 80. The cleaner case 119 of the air cleaner 118 is integrally provided with an intake duct 122 for sucking outside air from the outside. The upstream opening end of the intake duct 122 is a back wind from the radiator fan 26 and the condenser fan 27. It is arranged on the side opposite to the deflection direction and on the side of the engine body 22 (in this embodiment, on the right side of the engine body 22 when the vehicle is viewed from the front).

  Further, the air cleaner 118 is cooled by the cooling means 124, and the cooling means 124 is arranged in front of the engine body 22 so as to form a blower path 125 that directly applies traveling wind from the front of the vehicle to the actuator 60. In this embodiment, the plurality of components include an intake chamber 80 and a downstream side intake pipe extending from the intake chamber 80 to the intake port 33... Of the cylinder head 30. 88, a downstream side intake pipe 88 disposed on the rightmost side when viewed from the front of the vehicle, and a connection duct 120 connecting between the intake chamber 80 and the air cleaner 118, and the downstream side intake air when viewed from the front of the vehicle. The pipe 88..., The intake chamber 80 and the connecting duct 120 extend straight to the actuator 60. They are arranged to form a 25.

  Next, the operation of the first embodiment will be described. The volume of the intake chamber 80 that constitutes a part of the intake system 34 is set so that the ratio to the total displacement of the engine is a predetermined value or more. Thus, the minimum required volume of the intake chamber 80 is determined, and the intake chamber 80 can be easily installed even in a narrow space so that the volume of the intake chamber 80 does not become larger than necessary.

  Moreover, the predetermined value is set in consideration of at least one of improvement in engine output, silence of intake noise, and air-fuel ratio controllability, and takes into account at least one of important requirements related to engine operation. Since it can be designed, the design freedom of the intake chamber 80 can be increased.

  Furthermore, the predetermined value is set to 1.7 so as to satisfy all of the engine output improvement, the silence of the intake sound and the air-fuel ratio controllability, thereby sufficiently obtaining the dynamic effect of the intake air and releasing the intake sound. Can be suppressed. That is, the volumetric efficiency of the engine changes as shown in FIG. 15 with respect to the ratio of the volume of the intake chamber 80 to the total displacement, and the point at which the volume of the intake chamber 80 becomes 1.7 times the total displacement is the point. The gradient of volumetric efficiency changes at the boundary, and if the volume of the intake chamber 80 is less than 1.7 times the total displacement, the pressure in the intake chamber 80 cannot maintain the atmospheric pressure, and the dynamic effect of intake is sufficient. I can't get it.

  In addition, by increasing the capacity, the pressure in the intake chamber 80 can be maintained at almost atmospheric pressure, and interference of pulsation of other cylinders can be prevented, so that it is not affected by pulsation of other cylinders. The intake air amount to each cylinder can be made the same, and the controllability of the air-fuel ratio can be improved without performing complicated control such as correcting the fuel injection amount for each cylinder.

  That is, when the volume of the intake chamber 80 is less than 1.7 times the total displacement, for example, 1.5 times, the pressure in the intake chamber 80 becomes a negative pressure because the atmospheric pressure cannot be maintained, as shown in FIG. The air-fuel ratio varies from cylinder to cylinder and causes a problem in air-fuel ratio control. On the other hand, when the volume of the intake chamber 80 is 1.7 times or more of the total displacement, for example 1.7 times, the intake chamber The pressure in 80 can maintain atmospheric pressure, and as shown in FIG. 16B, the variation in air-fuel ratio among cylinders is suppressed to be small, and air-fuel ratio control is facilitated.

  Further, the sound pressure level of the intake sound that is released with respect to the ratio of the volume of the intake chamber 80 to the total displacement is changed as shown in FIG. 17, and the volume of the intake chamber 80 is 1.7 of the total displacement. The gradient of the sound pressure level changes at the double point, and the volume of the intake chamber 80 is set to 1.7 times or more of the total displacement, so that the release of the intake sound can be suppressed. Become.

  The intake chamber 80 has a plurality of connection ports 87 to be individually connected to the intake ports 33 of the cylinder head 30 on the upper side, and one side from the intake ports 33 along the cylinder arrangement direction 23. The connection ports 87 are arranged at positions shifted from each other, and are opposed to one side wall 30a of the cylinder head 30 so that one end protrudes laterally from one end of the cylinder head 30 in the engine body 22 along the cylinder arrangement direction 23. Have been placed. Moreover, a plurality of downstream side intake pipes 88 formed in the same shape so as to extend from the respective connection ports 87 to the intake port 33 side are arranged so as to obliquely intersect the cylinder arrangement direction 23 in a plan view. Is done.

  Therefore, the capacity of the intake chamber 80 can be increased while bringing the intake chamber 80 close to the engine body 22 side. In addition, the installation space of the intake chamber 80 can be set small by being close to the engine body 22, and the degree of freedom in setting the pipe length of the downstream side intake pipes 88 can be increased. As a result, the intake inertia effect of each cylinder can be utilized to the maximum, and the maximum output efficiency can be achieved.

  Further, a flange 89 to which the downstream ends of the downstream intake pipes 88 are commonly connected is fastened to one side wall 30a of the cylinder head 30 in common with the intake ports 33, and the intake chamber 80 along the cylinder arrangement direction 23 is connected. Since the width D1 is set larger than the width D2 of the flange 89, the capacity of the intake chamber 80 can be further increased, and the above-described effect can be further enhanced.

  Further, an intake chamber 80 and a generator 92 disposed on the other side of the intake chamber 80 along the cylinder arrangement direction 23 are arranged in the cylinder arrangement direction 23 at a position facing the one side wall 30 a of the cylinder head 30. The downstream intake pipes 88 are arranged so as to be inclined away from the generator 92 toward the intake chamber 80, so that the generator 92 is located at a position facing the one side wall 30a of the cylinder head 30. Despite being arranged, the intake chamber 80 and the respective downstream intake pipes 88 can be arranged more compactly.

  Furthermore, a plurality of upstream side intake pipes 93, which are individually connected to the upstream ends of the downstream side intake pipes 88, are accommodated in the intake chamber 80, and these upstream side intake pipes 93 are arranged in the cylinder arrangement direction. 23, it is formed so as to bend in a substantially U shape within a plane that obliquely intersects with 23, so that it is possible to increase the degree of freedom in designing the overall length of the downstream and upstream intake pipes 88 and 93, The degree of freedom in designing the upstream intake pipe 93 in the intake chamber 80 can be increased.

  Incidentally, the intake chamber 80 is configured by coupling the first and second chamber halves 81 and 82 to each other, and a reinforcing plate that reinforces the coupling portion of the first and second chamber halves 81 and 82. 107 is attached to the first chamber half 81 in the vicinity of the coupling surface of the first and second chamber halves 81, 82, so that it is not necessary to consider the sealing performance on both sides of the reinforcing plate 107, and the number of parts is reduced. It is possible to facilitate the assembly of both chamber halves 81 and 82. In addition, it is not necessary to provide the reinforcing plate 107 with a flange portion sandwiched between the chamber halves 81 and 82, and the weight of the reinforcing plate 107 can be reduced.

  Moreover, the rigidity of the first chamber half 81 itself is weaker than the rigidity of the second chamber half 82 itself, and the first chamber of the first and second chamber halves 81 and 82 has a weak rigidity. Since the reinforcing plate is attached to the half body 81, the rigidity of the first chamber half body 81 can be increased and the rigidity of the entire intake chamber 80 can be increased. Further, since the periphery of the reinforcing plate 107 is bent so as to form the bent portion 107a, the rigidity of the reinforcing plate 107 can be increased.

  In addition, the first and second chamber halves 81 and 82 are fastened to each other at a plurality of locations, and the reinforcing plate 107 is attached to the first chamber half 82 at a plurality of locations located between the fastening locations. The rigidity against vibration of the film surface can be increased.

  Further, the reinforcing plate 107 is attached to the first chamber half 81 with bolts 109... But the ribs 111 that are close to and opposed to the respective bolts 109 are provided on the second chamber half 82. In addition to preventing the reinforcing plate 107 from falling off the body 81, the rigidity of the intake chamber 80 with respect to membrane vibration can be increased.

  Moreover, the upstream side intake pipes 93... Accommodated in the intake chamber 80 are supported by the reinforcing plate 107, and the durability of the upstream side intake pipes against vibration can be improved. Further, the reinforcing plate 107 is formed in a shape that avoids inhibition of fresh air inflow to the upstream end opening of the upstream side intake pipes 93... And prevents the fresh air inflow to the upstream side intake pipes 93. Thus, the engine output can be improved.

  By the way, the downstream ends of the upstream side intake pipes 93 are connected to the upstream ends of the downstream side intake pipes 88 through the first chamber half 81, so that the assemblability can be improved. That is, in the structure in which the reinforcing plate 107 is sandwiched between the coupling surfaces of the two chamber halves 81 and 82, when the upstream side intake pipes 93 ... accommodated in the intake chamber 80 are supported by the reinforcing plate 107. , It is necessary to consider simultaneously the seals of the connection portions of the upstream side intake pipes 93... And the downstream side intake pipes 88... And the connection portions of the downstream side intake pipes 88. Although it is necessary to make the assembly highly accurate, the reinforcing plate 107 is attached to the first chamber half 81 and the upstream side intake pipe 93 and the downstream side intake pipe 88 are connected through the first chamber half 81. In such a configuration, the upstream side intake pipe 93... And the downstream side intake pipe 88... And the reinforcing plate 107 may be assembled to the first chamber half 81. Never Engineering and assembly is required, it become possible to enhance the assemblability.

  Further, since the intake air amount is adjusted by controlling the opening and closing of the intake valves 38..., The throttle valve is not interposed in the intake system 34 including the intake chamber 80, and thus the intake sound is easily released to the outside. By reinforcing the chamber 80 with the reinforcing plate 107, it is possible to increase the film surface rigidity of the intake chamber 80 and reduce intake noise.

  The actuator 60 for controlling the opening and closing of the intake valves 38 is attached to the cylinder head 30 of the engine main body 22, and the back wind from the radiator fan 26 disposed in front of the engine main body 22 constitutes a part of the intake system 34. The intake chamber 80 disposed between the radiator fan 26 and the actuator 60 prevents direct contact with the actuator 60. As a result, even during the idling operation where the radiator fan 26 often rotates, the idling operation can be stabilized by preventing the heat effect of the back wind from the radiator fan 26 from affecting the actuator 60, and the intake chamber 80 can be Since it also serves as a back wind protection means, a dedicated member for back wind protection is unnecessary, and it is possible to simplify the structure while avoiding an increase in the number of parts.

  The radiator fan 26 is disposed in front of the engine main body 22 so as to deflect the back wind to either the left or right side, and the actuator 60 has a back wind deflection direction from the radiator fan 26 on the left and right end walls of the engine main body 22. Since it is attached to the end wall of the cylinder head 30 on the opposite side, it is possible to reduce the amount of back air from the radiator fan 26 toward the actuator 60 side, and to stabilize the idle operation.

  Further, since the upstream opening end of the intake duct 122 provided at the upstream end of the intake system 34 is disposed on the side of the engine body 22 on the side opposite to the back wind deflection direction from the radiator fan 26, the radiator fan 26 is connected to the intake duct 122. As a result, the engine output can be improved and the idle stability can be achieved at the same time.

  Further, the actuator 60 is cooled by the cooling means 124, and the cooling means 124 is arranged in front of the engine body 22 so as to form a ventilation path 125 that directly applies the traveling wind from the front of the vehicle to the actuator 60. In this embodiment, the plurality of parts are an intake chamber 80 constituting a part of the intake system 34, and a downstream intake pipe extending from the intake chamber 80 to the intake port 33 side. 88, and a connection duct 120 connecting between the intake chamber 80 and the air cleaner 118, and when viewed from the front of the vehicle, the downstream intake pipe 88, the intake chamber 80, and the connection duct 120 extend linearly to the actuator 60. Are arranged to form.

  Therefore, the actuator 60 can be cooled with the traveling wind using a plurality of components arranged in front of the engine body 22, and the actuator 60 can be cooled while avoiding an increase in the number of components. In addition, the downstream side intake pipe 88, the intake chamber 80, and the connection duct 120 constitute the intake system 34, and the traveling wind does not warm even when the traveling wind hits, and the actuator 60 is efficiently cooled. Can do.

  Thus, by cooling the actuator 60 by the cooling means 124, the intake air amount can be controlled with high accuracy so that the actuator 60 is not affected by heat even during low load operation.

  As another embodiment of the present invention, as indicated by a chain line in FIGS. 1 and 2, a duct that opens to one end of the front of the vehicle and extends to the actuator 60 may be used as the cooling means 126. In this case, the actuator 60 can be efficiently cooled by the outside air without being affected by the back wind from the radiator fan 26 and the radiant heat from the engine body 22. At this time, the cooling means 124 may be supported by the engine body 22 or the vehicle body, and if the opening area of the rear end of the duct is reduced, the cooling effect can be further enhanced by the nozzle effect.

  FIG. 18 shows a second embodiment of the present invention. The parts corresponding to the first embodiment are indicated by the same reference numerals, and the detailed description is omitted.

  The intake chamber 80 ', which also functions as a back wind protection means, is coupled to a first chamber half 81' that is a bowl-like shape that opens downward and a second chamber half 82 'that is a bowl-like shape that opens upward In the intake chamber 80 ', as in the first embodiment, the connection pipe portions 86 ..., the downstream side intake pipes 88 ... and the connection pipes 90 ... The upstream intake pipes 93 are connected to the intake ports 33 (see the first embodiment) of the cylinder head 30 via the first embodiment), and the upstream intake pipes 93 are accommodated in the first chamber. Supported by a reinforcing plate 107 attached to the half 81 '.

  In addition, the direction of orientation of the upstream end opening of the upstream side intake pipe 93... Is connected to one of the first and second chamber halves 81 ′ and 82 ′ so as to be connected to the air cleaner 118 (see the first embodiment). It is set differently from the directivity direction of the pipe part 116 '. Thus, in this second embodiment, the upstream end of the upstream side intake pipes 93... Opens obliquely upward, so that the lower first of the first and second chamber halves 81 ′, 82 ′. The two-chamber half body 82 'is provided with a connecting pipe portion 116' oriented obliquely downward.

  According to the second embodiment, it is possible to contribute to the reduction of the intake sound. That is, the intake sound is likely to be released from the intake system to the atmosphere due to the intake system not having a throttle valve, but the directivity direction of the upstream end opening of the upstream intake pipe 93 ′ in the intake chamber 80 ′. However, since the direction of the connecting pipe 116 ′ provided in the second chamber half 82 ′ is different from that of the connection chamber 116 ′, the propagation of the intake sound to the air cleaner 118, which is the upstream end of the intake system, is suppressed, and the intake sound is reduced. It can be done.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the above embodiment, a variable valve engine has been described in which the intake amount is adjusted by continuously changing the lift amount of the intake valve 38. However, Patent Document 1 (Japanese Patent No. 3494049) discloses a variable valve engine. As disclosed, the present invention is also applicable to a variable valve engine in which the intake air amount is adjusted by varying the closing timing of the intake valve that is opened and closed by a solenoid that is an actuator.

It is a side view of the variable valve engine in the vehicle mounting state in 1st Example. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. FIG. 3 is a view taken in the direction of arrow 3 in FIG. 1. Fig. 4 is a view taken along line 4-4 in Fig. 3. It is a vertical side view of the valve gear for intake valves. It is a disassembled perspective view of the valve gear for intake valves. It is a vertical side view of an actuator. It is a top view of an intake chamber and an upstream intake pipe. FIG. 9 is a sectional view taken along line 9-9 in FIG. 8. FIG. 10 is a sectional view taken along line 10-10 in FIG. 8. It is the 11-11 line sectional view of FIG. It is a top view of the 2nd chamber half body seen from the 12-12 line arrow direction of FIG. It is a top view of a reinforcement plate and a downstream intake pipe. It is the 14-14 line expanded sectional view of FIG. It is a figure which shows the change of the volume efficiency by the ratio of the intake chamber volume with respect to the total displacement. It is a graph which shows the dispersion | variation degree of the air fuel ratio by the ratio of the intake chamber volume with respect to the total displacement. It is a figure which shows the change of the intake sound by the ratio of the intake chamber volume with respect to the total displacement. It is sectional drawing corresponding to FIG. 11 of the intake chamber of 2nd Example.

22 ... Engine body 26 ... Radiator fan 30 ... Cylinder head 33 ... Intake port 34 ... Intake system 38 ... Intake valve 60 ... Actuator 80, 80 '... Back wind protection Intake chamber 122 as means for intake duct

Claims (3)

An intake valve (38) is disposed in the cylinder head (30) of the engine body (22) disposed behind the radiator fan (26) so as to be able to open and close, and the intake valve (38) is adjusted so as to regulate the intake amount. ) Is attached to the engine body (22), and the intake system (34) having no throttle valve is connected to the intake port (33) of the cylinder head (30). In variable valve engine,
Between the radiator fan (26) and the actuator (60), the intake system (34) also serves as a back wind protection means for preventing a back wind from the radiator fan (26) from directly hitting the actuator (60 ). vehicle variable valve engine in which the intake chamber (80, 80 ') is characterized in that it is arranged to constitute a part of. A radiator fan (26) is arranged in front of the engine body (22) mounted on the vehicle with the crank axis along the left-right direction so as to deflect the back wind to either the left or right, and the actuator (60) 2. The variable valve for a vehicle according to claim 1, wherein the variable valve for a vehicle according to claim 1 is attached to an end wall on a side opposite to a back wind deflection direction from the radiator fan (26) among left and right end walls of the engine body (22). engine. An upstream opening end of an intake duct (122) provided at the upstream end of the intake system (34) is disposed on the side of the engine body (22) on the side opposite to the back wind deflection direction from the radiator fan (26). The variable valve engine for a vehicle according to claim 2 .

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