JP3966297B2 - Engine intake system - Google Patents

Description

  The present invention relates to an intake device for an engine.

  In recent years, in vehicles, weight reduction and downsizing have been promoted against the background of improved fuel efficiency. As a result, the volume of the engine room tends to be small, and the structure of the engine and the layout of the engine in the engine room are becoming difficult.

  For example, Patent Document 1 discloses an engine in which an intake manifold is disposed on an upper portion of a front side surface of an engine mounted horizontally in an engine room. In this engine, substantially the entire intake manifold including the intake manifold and the intake manifold is disposed so as to protrude from the engine body toward the front of the vehicle, and the occupied space in the longitudinal direction of the engine in a narrow engine room is large.

  As an improvement measure, as in the engine disclosed in Patent Document 2, in an engine of a front intake rear exhaust mounted horizontally in an engine room, each intake manifold is connected to the upper part of the front side of the vehicle from the intake port above the cylinder head cover. There is one that extends to the rear side of the vehicle through and is connected to an intake manifold disposed in the rear portion of the engine. In such a structure, the forward protrusion of the engine in the vehicle can be suppressed, and the space occupied by the engine in the engine room can be reduced in the vehicle front-rear direction compared to the structure disclosed in Patent Document 1.

The engine disclosed in Patent Document 2 is provided with a communication pipe that extends in the cylinder row direction over the entire intake manifold and communicates with each intake manifold, and the communication pipe is connected to each intake manifold. It communicates in the middle of the pipeline from the intake port to the intake manifold. An intake pipe length variable device is configured to switch the apparent intake pipe length according to the engine speed by opening and closing an on-off valve disposed at a communication port between the communication pipe and each intake manifold. The communication pipe is attached from the outside of the engine to a portion of the intake manifold that is folded back to the upper front side and the rear side of the vehicle.
JP 2003-322059 A Japanese Patent No. 2709128

  By the way, in a narrow engine room, it is necessary to ensure a crushable zone between the engine and the bonnet above it as well as the crushable zone in front of the engine. Therefore, in the configuration disclosed in Patent Document 2, the engine is inclined forward toward the front of the vehicle, and a space is secured between the bonnet where the ground height decreases toward the front of the vehicle and the communication pipe.

  However, even if the intake manifold is disposed above the cylinder head cover to prevent the engine from protruding forward, the engine is inclined forward so that the space occupied by the engine in the longitudinal direction of the vehicle It becomes larger than the case where it arranges. As a result, the occupied space in the vehicle front-rear direction of the engine cannot be effectively reduced.

  The present invention has been made in view of such points, and the object thereof is to suppress the protrusion of the intake manifold to the front of the vehicle, while suppressing the occupied space in the vehicle front-rear direction of the engine including the intake manifold, A crushable zone is secured between the engine and the bonnet, and an intake pipe length variable device for the intake manifold is effectively disposed.

  The first invention is directed to an in-line multi-cylinder engine intake device that is horizontally installed in an engine room of a vehicle such that an intake port is positioned on a front side surface of the vehicle and an exhaust port is positioned on a rear side surface of the vehicle.

  A plurality of intake manifolds extending from the intake port to above the cylinder head cover of the engine and extending toward the rear of the vehicle; and an intake manifold that communicates with the intake manifold on the vehicle rear side of the engine It is assumed that an intake manifold having a pipe and an intake pipe length varying device that changes the intake pipe length is provided.

  The variable intake pipe length device includes: a short pipe communicating with each intake manifold; a variable intake expansion chamber communicating with each intake manifold via the short pipe; the expansion chamber and each intake manifold; The engine room is defined by a forwardly inclined bonnet whose upper surface is inclined so that the ground height decreases toward the front of the vehicle. The intake manifold is disposed so as to be inclined so that the rear side of the vehicle rises along the forwardly inclined shape of the bonnet at a position above the cylinder head cover, and the expansion chamber is disposed on the intake manifold. It arrange | positions between the vehicle rear side part and the said cylinder head cover. Here, the expansion chamber includes one in which at least a part thereof is disposed in a space between the vehicle rear side portion of the intake manifold and the cylinder head cover.

  In the case of the above configuration, the engine is mounted horizontally in the engine room, and the intake port for introducing intake air is located on the vehicle front side surface of the engine. The intake manifold of the intake manifold that communicates with the intake port extends from the intake port to the rear of the vehicle through the top of the cylinder head cover of the engine, and the intake manifold that communicates with the intake manifold is the engine. Is disposed on the vehicle rear side. Here, the vehicle rear side of the engine means the vehicle rear side with respect to the vehicle direction with respect to the vehicle direction, and is not limited to the space behind the vehicle and above the engine with respect to the engine center. It also includes the space behind the vehicle.

  For this reason, compared to a configuration in which the intake manifold and the intake manifold are substantially entirely disposed in front of the engine where the intake port opens, the intake manifold is prevented from projecting forward of the engine, The full width of the engine can be reduced.

  As a result, as in Patent Document 1, in a configuration in which an intake manifold having a substantially triangular shape in a vehicle side view is disposed in front of and above the engine, in order to ensure a crushable zone in front of the engine, There is no need to tilt the engine to the rear of the vehicle. That is, even if the engine is disposed substantially vertically, the crushable zone can be secured because the width of the entire engine is suppressed.

  Further, the intake manifold that extends above the cylinder head cover is inclined so that the rear of the vehicle becomes higher along the forwardly inclined shape of the bonnet. Thereby, a crushable zone is secured between the intake manifold and the bonnet.

  Further, the intake manifold is disposed to be inclined so that the rear side of the vehicle is higher, so that a space is formed between the vehicle rear side of the intake manifold and the cylinder head cover. The intake pipe length varying device can be arranged by utilizing the space above the cylinder head cover. The intake pipe length varying device has an intake expansion chamber disposed in a space between the rear side of the intake manifold and the cylinder head cover. The expansion chamber for intake is in communication with each intake manifold through the short pipe. The expansion chamber and the communication pipe are switched between the communication state and the shut-off state by an on-off valve disposed in the short pipe. The intake pipe length varying device includes, for example, a conduit that passes from the intake manifold to the expansion chamber, each short pipe, and each intake manifold by communicating the expansion chamber with the intake manifold and opening and closing the on-off valve. It is also possible to switch between a short high-speed intake path and a low-speed intake path having a long pipe length that passes from the intake manifold to all the intake manifolds. Further, for example, the expansion chamber may be communicated only with the short pipe of each intake manifold, and may serve as a communication pipe that communicates each intake manifold in the middle of the pipeline. In this configuration, the apparent intake pipe length may be switched by changing the pressure reversing unit where the basic pressure wave of the intake air is reversed by opening and closing the on-off valve.

  Therefore, according to the first aspect of the present invention, it is possible to prevent the intake manifold from protruding forward of the vehicle and to secure a crushable zone in front of the engine of the vehicle. In addition, by arranging the intake manifold so as to be higher along the forward leaning shape of the bonnet so that the rear of the vehicle is higher, a crushable zone can be secured between the intake manifold and the bonnet, and the intake manifold can be secured. The intake pipe length varying device can be effectively arranged below the rear side of the vehicle and above the cylinder head cover.

  According to a second aspect of the present invention, in the first aspect, each of the intake manifolds is an upstream curved portion whose upper end is curved downward and communicates with the intake manifold, and the intake manifold and the expansion chamber Is arranged in parallel in the vehicle front-rear direction in the rear view of the engine on the vehicle front side with respect to the upstream curved portion.

  In the case of the above configuration, each intake manifold has a curved portion that curves downward at its upstream end. The bending portion communicates with the intake manifold located below the bending portion. At this time, on the vehicle front side of the intake manifold, the expansion chamber located below the vehicle rear side portion of the intake manifold is arranged in parallel.

  Therefore, the expansion chamber and the intake manifold are located below the rear side of the intake manifold, but they are not arranged in the vertical direction but are aligned in the longitudinal direction of the vehicle. Established. Therefore, the height of the intake manifold is suppressed. Also, with this configuration, the length of the intake manifold can be increased and the low-speed torque of the engine can be improved. Furthermore, since the intake manifold conceals the expansion chamber and the intake manifold in plan view of the engine, the appearance of the upper surface of the engine is improved even when the engine cover is not provided.

  According to a third invention, in the first or second invention, the engine has a spark plug unit that stands upright at the center of each cylinder and protrudes upward from the upper surface of the cylinder head cover. The on-off valve is disposed on the vehicle front side of the spark plug unit, and the valve shaft of the on-off valve extends in the cylinder row direction of the engine. It shall be.

  In the case of the above configuration, the expansion chamber can be disposed by effectively utilizing the space between the spark plug unit and the intake manifold.

  On the other hand, the valve shaft of the on-off valve extending in the cylinder row direction is disposed on the front side of the vehicle with respect to the spark plug unit, so that when the drive shaft for driving the on-off valve is provided, the open / close for each intake manifold is opened and closed. One shaft shaft coupled to all of the valves can be provided avoiding interference with the spark plug unit.

  Further, since the opening / closing valve is located in front of the ignition plug unit, the communication portion between the short pipe and the intake pipe where the opening / closing valve is disposed is also positioned in front of the ignition plug unit. The intake pipe length difference due to opening and closing of the valve can be increased. As a result, it is possible to optimize the intake charging efficiency over a wide range of engine speeds.

  In the fourth invention, the engine is an in-line four-cylinder engine. The first to fourth intake manifolds corresponding to the first to fourth cylinders of the engine are juxtaposed above the cylinder head cover, and the intake manifold is connected to the first intake manifold in the cylinder row direction. A fresh air pipe communicating with the air cleaner unit is connected to the lower portion of the four intake manifolds, and the second cylinder and the second cylinder are connected to the air cleaner unit. The upstream and downstream ends of the second and third intake manifolds corresponding to the three cylinders are connected to the upper part of the intake manifold pipe from above, and the first and fourth cylinders corresponding to the first and fourth cylinders, respectively. The intake manifold is connected from the side to the front side of the vehicle from the connection portion of the second and third intake manifolds in the intake manifold, and the lengths of the first to fourth intake manifolds are: It is set to approximately the same length.

  In the case of the above configuration, the four cylinders are the first cylinder, the second cylinder,..., The fourth cylinder in order from the front of the engine, and the four intake manifolds corresponding thereto are the first intake manifold and the second intake manifold. The pipe, the third intake manifold, and the fourth intake manifold are juxtaposed above the cylinder head cover. The intake manifold pipe is disposed on the vehicle rear side of the engine at a position corresponding to a substantially central position between the first intake manifold and the fourth intake manifold in the cylinder row direction. In other words, the intake manifold is disposed at a position opposite to the second intake manifold and the third intake manifold, and has a compact configuration in the cylinder row direction. The intake manifolds are arranged so that the first to fourth intake manifolds have substantially the same length.

  Therefore, compared with the case where a large intake manifold extending in the longitudinal direction of the engine is provided, the intake system is made compact by making each intake manifold as the above-mentioned configuration as a small manifold having a minimum capacity. In addition, the length of each intake manifold can be made long and equal to improve the low-speed torque of the engine, and the intake charge efficiency from each intake manifold to the cylinder can be made uniform.

  According to a fifth invention, in any one of the first to fourth inventions, each intake manifold is erected at a central portion of each cylinder in an engine plan view and protrudes upward from the upper surface of the cylinder head cover. It is assumed that the ignition plug unit is offset in the front-rear direction of the engine, and at least a part of the ignition plug unit is disposed so as to overlap the vertical direction of the ignition plug unit in the rear view of the engine.

  In the case of the above-described configuration, the ignition plug unit that stands upright at the center of each cylinder of the engine protrudes from the upper surface of the cylinder head cover. It is offset in the longitudinal direction of the engine with respect to the plug unit, so that adjacent intake manifolds are arranged so as to sandwich the spark plug unit. Then, in the rear view of the engine, by arranging at least a part of each intake manifold overlapping the spark plug unit in the vertical direction, each intake manifold avoids interference with each spark plug unit, The overall height of the engine can be suppressed by the amount that the intake manifold and each spark plug unit overlap in the vertical direction.

  That is, the intake manifold can be arranged in a compact manner while suppressing the overall width and height of the engine. As a result, the space occupied by the entire engine including the intake manifold in a narrow engine room can be further reduced.

  According to the above invention, in the intake system for an in-line multi-cylinder engine that is horizontally installed in the engine room so that the intake port is positioned on the front side surface of the vehicle, the intake manifold extends from the intake port above the cylinder head cover. By extending rearward through the vehicle, the entire width of the engine including the intake system can be suppressed, and as a result, a crushable zone can be secured in front of the vehicle of the engine. In addition, even if the engine is arranged substantially vertically, the above-described intake manifold is inclined so that the rear of the vehicle rises along the forwardly inclined shape of the bonnet, so that a crushable zone is formed between the intake manifold and the bonnet. And the intake pipe length varying device can be effectively disposed below the rear side of the intake manifold and above the cylinder head cover.

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

Embodiment 1 of the Invention
1 to 6 show an engine according to a first embodiment of the present invention. 1 is an engine room located at the front of the vehicle, 11 is a shroud upper that defines the front end of the engine room 1, and 12 is disposed on the upper surface of a dash panel (not shown) that defines the rear end of the engine room 1. The cowl upper panel 13 is a bonnet that inclines so as to lower the ground height toward the front of the vehicle and defines the upper surface of the engine room 1, and 14 is a radiator disposed in front of the engine 2. 2 is an in-line 4-cylinder engine installed horizontally in the engine room 1, 7 is a battery, and 8 is a vacuum booster for a brake.

  As shown in FIGS. 1 and 2, the engine room 1 is particularly narrow in the vehicle front-rear direction, and the engine 2 is mounted horizontally and substantially vertically in the narrow engine room 1. An air cleaner unit 6 is disposed behind the engine 2 (left side in the vehicle width direction). A battery 7 is disposed on the left side of the engine 2 and a vacuum booster 8 is disposed on the right side and the rear of the vehicle. Thus, even in a small engine room 1, space is effectively utilized with the engine 2 at the center. Further, among engine functional components, the battery 7 and the vacuum booster 8 having a relatively large volume are arranged on the left and right in the width direction of the engine room 1 to balance the layout in the engine room 1.

  The engine 2 is an in-line four-cylinder engine in which four cylinders (not shown) are arranged in series in the engine longitudinal direction. Two cam sprockets provided at the front end of a camshaft (not shown) disposed in the cylinder head and a crank sprocket provided at the engine front end of the crankshaft are provided at the front of the engine (on the right side in FIG. 1). The timing chain 23 is wound around the cam sprocket and the crank sprocket. A chain chamber 24 for accommodating these sprockets and the timing chain 23 is defined. A transmission 25 is disposed at the rear of the engine (left side in FIG. 1) (shown only in FIGS. 4 and 6). In addition, an intake port that individually communicates with each cylinder is provided on the left side of the engine (upper side in FIG. 1), while the intake port that individually communicates with each cylinder is provided on the right side of the engine (lower side in FIG. 1). An exhaust port is provided. Thus, the engine 2 is a front intake and a rear exhaust.

  In the engine 2, as shown in FIG. 4, a cylinder head 22 is disposed on an upper portion of a cylinder block 21, and the upper portion of the cylinder head 22 is covered with a cylinder head cover 3. Further, the front end portion 3 a of the cylinder head cover 3 extends forward of the engine from the front end of the cylinder head 22, and defines the upper surface of the chain chamber 24. The cylinder head cover front end 3a is provided with an engine oil injection port 3b for injecting engine oil. .. Are erected in the center of each cylinder, and each spark plug unit 31 protrudes upward from the cylinder head cover 3. The spark plug units 31 are arranged in a straight line at equal intervals in the longitudinal direction of the engine in a plan view of the engine, and are arranged in a straight line with the intake and exhaust ports in the engine width direction. The first cylinder 31a, the second cylinder 31b, the third cylinder 31c, and the fourth cylinder 31d are sequentially arranged from the front of the engine.

  As shown in FIG. 3, the intake manifold 4 for sending intake air to the cylinders via the intake port is disposed so as to cover the upper side of the engine 2. The intake manifold 4 includes four independent intake manifolds 41, 41,..., An intake manifold 45 communicating with the intake manifolds 41, 41,. And an intake pipe length varying device 46 that optimizes the charging efficiency of the intake air by switching the. The intake manifold 4 is attached to the intake side of the engine 2 via an EGR distribution unit 49.

  On the other hand, as shown in FIG. 4, the exhaust manifold 5 that discharges the burned gas in the cylinder via the exhaust port is disposed on the right side surface of the engine 2. The exhaust manifold 5 includes an exhaust manifold that communicates with each exhaust port and an exhaust manifold that collects the exhaust manifold into one. A part of the exhaust gas is sent to the EGR distribution unit 49 via the EGR hose 51 and recirculated.

  Each intake manifold 41 is located on the front side of the vehicle with respect to the engine 2 and communicates with the intake port, and an extended portion 43 that is located above the cylinder head cover 3 and continues to the downstream curve portion 42. And an upstream curved portion 44 that is located on the vehicle rear side and continues to the extending portion 43. The intake manifold 45 is disposed on the rear side of the engine 2 and the end of the upstream curved portion 44 communicates with the intake manifold 45. The first intake manifold 41a, the second intake manifold 41b, the third intake manifold 41c, and the fourth intake manifold 41d are arranged in order from the front of the engine, and the downstream curved portion 42, the extending portion 43, and the upstream curved portion corresponding thereto, respectively. The part 44 is also denoted by the same reference signs a to d.

  As shown in FIGS. 1 and 3, each extending portion 43 is a substantially straight pipe extending in the vehicle front-rear direction, and is offset to the front side of the engine with respect to the spark plug unit 31 erected on the corresponding cylinder. Yes. That is, the first extending portion 43a is located between the spark plug unit 31 at the forefront of the engine and the engine oil inlet 3b. The 2nd-4th extending | stretching part 43b-43d is located between the two adjacent spark plug units 31, respectively.

  Further, as shown in FIGS. 3 and 5, each extending portion 43 is disposed so that the rear side of the vehicle becomes higher along the forward inclined shape of the bonnet 13, and is one with the spark plug unit 31 in the rear view of the engine. The parts overlap.

  As shown in FIGS. 3, 5, and 6, each of the downstream curved portions 42 extends from the intake ports to the front and the top of the vehicle, curves further to the rear of the vehicle, and continues to the extending portions 43. . Then, as shown in FIG. 6, the downstream curved portions 42 are arranged so that, when the engine 2 is viewed from the front of the vehicle, the upper portions of the downstream curved portions 42 are positioned on the front side of the engine with respect to the lower portions. Inclined to. In this way, the intake port and the extending portion 43 which are arranged to be shifted from each other in the longitudinal direction of the engine communicate with each other.

  As shown in FIGS. 3 and 5, the upstream curved portions 44 are continuous with the extending portions 43, are curved downward, and communicate with the intake manifold 45.

  As shown in FIGS. 1 and 4, the intake manifold 45 is located below the intake manifold 41 on the vehicle rear side above the engine 2 from the position of the first upstream curved portion 44a to the fourth upstream curved portion 44d. It extends to the position in the cylinder row direction. The end of each upstream curved portion 44 is connected to the upper surface of the intake manifold 45, and a manifold-side fresh air pipe 45a extends substantially horizontally toward the rear of the engine at the rear end of the engine. Has been.

  Thus, a space is formed between the vehicle rear side portion of the intake manifolds 41, 41,... Arranged so that the rear of the vehicle becomes higher and the cylinder head cover 3, and the intake manifold 41, The intake pipe length varying device 46 is disposed utilizing the space below 41,... And above the cylinder head cover 3.

  As shown in FIG. 5, the intake pipe length varying device 46 intersects each extending portion 43 in the engine plan view between the intake manifold 45 and the spark plug units 31, 31,. An expansion chamber 46a extending in the cylinder row direction, an opening 46b formed at a substantially central portion in the longitudinal direction of each of the extending portions 43, and passing through the lower side of each extending portion 43 from each of the openings 46b. It comprises a short pipe portion 46c communicating with the expansion chamber 46a from the front of the vehicle, and an opening / closing valve 46d disposed in each short pipe portion 46c. The expansion chamber 46a is juxtaposed to the intake manifold 45 in the rear view of the engine, and the rear end of the vehicle communicates with the intake manifold 45 in the cylinder row direction. As a result, the intake manifold 45 and the extending portions 43 communicate with each other through the short pipe portions 46c.

  The on-off valve 46d is switched between open and closed in accordance with the engine speed. As a result, each intake air intake pipe 45 passes through each upstream bending portion 44, each extending portion 43, and each downstream bending portion 42. A low-speed intake path having a long pipe line that feeds intake air to the port, each intake port from the intake manifold 45 through the expansion chamber 46a, each short pipe portion 46c, the downstream portion of the extending portion 43, and each downstream curved portion 42 It is possible to switch between a high-speed intake path with a short pipe length for sending intake air to the pipe.

  Each on-off valve 46d is positioned on the vehicle front side with respect to each spark plug unit 31, and its valve shaft 46e extends in the cylinder row direction of the engine. Therefore, one shaft shaft (not shown) that drives all the on-off valves 46d can be extended in the cylinder row direction while avoiding interference with each spark plug unit 31. Furthermore, by disposing each opening / closing valve 46d on the front side of the vehicle with respect to each spark plug unit 31, the respective openings 46b are necessarily positioned on the front side of the vehicle with respect to each spark plug unit 31. As a result, the difference in pipe length between the low-speed intake path and the high-speed intake path can be increased, and intake charge efficiency can be optimized for a wide range of engine speeds.

  As shown in FIGS. 1, 3, and 6, the air cleaner unit 6 includes an air cleaner case 61 and two resonance chambers 62 and 63 that are separately formed, and are integrally disposed above the transmission 25. Has been.

  As shown in FIG. 2, the air cleaner case 61 has an upper dusty side chamber 61a and a lower clean side chamber 61b. The dusty side chamber 61a and the clean side chamber 61b are defined by air cleaner elements 61c that are inclined. The clean side chamber 61b has a fresh air outlet 61e on the vehicle rear side.

  The air cleaner element 61c is inclined so that its height position increases toward the rear of the vehicle. Therefore, the area of the air cleaner element 61c in the air cleaner case 61 can be increased as compared with the case where the air cleaner element 61c is arranged vertically or horizontally with respect to the air cleaner case 61. In addition, the clean side chamber 61b is thus expanded in the vertical direction toward the rear of the vehicle, and the vehicle rear portion of the clean side chamber 61b is sufficient for disposing the fresh air outlet 61e. Space is reserved.

  As shown in FIGS. 2 and 4, the lower portion of the air cleaner case 61 is arranged at a position overlapping the cylinder head cover 3 and the cylinder head 22 in the rear view of the engine, and the arrangement position of the air cleaner unit 6 is as low as possible. Has been.

  The fresh air outlet 61e extends rearward and upward from the rear side of the clean side chamber 61b. The upstream end of the air cleaner-side fresh air pipe 61f is connected to the fresh air outlet 61e. The downstream end of the air cleaner side fresh air pipe 61f is curved toward the intake manifold 45 and is connected to the upstream side of the throttle valve unit 61g. On the other hand, the manifold side fresh air pipe 45a is connected to the downstream side of the throttle valve unit 61g.

  Since the manifold-side fresh air pipe 45a extends substantially horizontally from the intake manifold 45, the air cleaner-side fresh air pipe 61f and the throttle valve unit 61g are substantially the same as the intake manifold 4 as shown in FIG. They are the same height and do not protrude upward from the engine to increase the overall height of the engine.

  Further, as shown in FIG. 1, the resonance chamber 62 is adjacent to the front side of the engine of the dusty side chamber 61a, and a part thereof is formed by the fourth intake manifold 41d being offset to the front side of the engine. The cylinder head cover 3 is disposed in a space above the cylinder head cover 3 so as to overlap the cylinder head cover 3 in plan view of the engine.

  The resonance chamber 63 is adjacent to the vehicle rear side of the clean side chamber 61b below the air cleaner side fresh air pipe 61f as shown in FIGS.

  The fresh air introduced into the dusty side chamber 61a is purified by the air cleaner element 61c and introduced into the clean side chamber 61b. The fresh air taken out from the fresh air outlet 61e at the rear of the vehicle in the clean side chamber 61b passes from the air cleaner side fresh air pipe 61f through the manifold side fresh air pipe 45a via the throttle valve unit 61g and passes through the intake manifold. 4 is sent to the intake manifold 45. By providing the two resonance chambers 62 and 63, resonance vibrations at two different frequencies are suppressed.

  In the case of the above-described configuration, as shown in FIGS. 3 and 5, the intake manifold 4 has the extending portion 43 disposed above the engine 2, so that it protrudes forward from the left side surface of the engine 2 to the front of the vehicle. Only the downstream curved portions 42 are provided, and the engine width, that is, the outer dimension in the vehicle front-rear direction can be reduced.

  As shown in FIGS. 3, 5, and 6, even if the extending portion 43 is disposed above the cylinder head cover 3, the extending portion 43 is engine-driven relative to the spark plug unit 31 protruding above the cylinder head cover 3. Since it is offset forward and disposed so as to overlap the spark plug unit 31 in the rear view of the engine, the overall height of the engine is suppressed as much as possible.

  Further, as shown in FIG. 6, the offset of each extending portion 43 toward the front of the engine is such that each downstream curved portion 42 is located on the front side of the engine from the front side of the vehicle. This is realized by tilting the Thus, even if the height position of the extending portion 43 is lowered and the height difference between the intake port and the extending portion 43 is reduced, the curvature radius of each downstream curved portion 42 is increased, and as a result, the intake manifold 4 is suppressed, and the charging efficiency of intake into each cylinder is improved.

  Further, as shown in FIG. 1, each extending portion 43 is offset to the front of the engine rather than to the rear of the engine with respect to each spark plug unit 31, thereby providing a cylinder head cover at the rear of the engine rather than the fourth extending portion 43 d. 3 A space above is secured. The engine oil injection port 3b is formed in the cylinder head cover front end 3a, so that a space is secured in front of the spark plug unit 31 at the forefront of the engine, and the first extending portion 43a, the engine oil injection port 3b, Does not interfere.

  Further, the air cleaner unit 6 is shifted while effectively utilizing the space above the cylinder head cover 3 behind the engine rather than the spark plug unit 31 at the rear end of the engine, which is secured by offsetting the extending portion 43 toward the front of the engine. It can be arranged above the machine 25.

  Further, since the overall width of the engine 2 including the intake manifold 4, that is, the outer dimension in the vehicle front-rear direction is reduced, the engine 2 is moved rearward in order to reduce the space occupied by the engine 2 in the vehicle front-rear direction. It is not necessary to incline, and as shown in FIG. 2, even if the engine 2 is disposed substantially vertically, a crushable zone can be secured between the engine 2 and the radiator 14 positioned in front of the vehicle.

  The intake manifold 41 is disposed along the forwardly inclined shape of the bonnet 13 so that the rear of the vehicle becomes higher, so that the intake manifold 41 and the bonnet 13 are arranged between the intake manifolds 41 and the bonnet 13. A crushable zone is secured along the longitudinal direction of the tube 41.

  At the same time, the intake pipe length varying device 46 is compactly arranged in a substantially triangular space formed by the intake manifolds 41, 41,..., The cylinder head cover 3 and the intake manifold 45. Can do. In other words, the expansion chamber 46a and the intake manifold 45 are positioned below the intake manifolds 41, 41,..., Because they are not overlapped in the vertical direction but are provided side by side in the vehicle longitudinal direction. The overall height of the intake manifold 4 is suppressed.

  Further, since the expansion chamber 46a and the intake manifold 45 in the plan view of the engine are concealed by the intake manifolds 41, 41,..., The appearance of the upper surface of the engine 2 is improved even when the engine cover is not provided. .

  Further, each intake manifold 41 is extended from the vehicle front side of the engine 2 to the vehicle rear side by the downstream curved portion 42, the extending portion 43, and the upstream curved portion 44, so that the length of the intake manifolds 41, 41,. The length can be increased, and the low-speed torque of the engine 2 can be improved.

  Therefore, as a result, the engine 2 can be mounted compactly in the vehicle front-rear direction while having the radiator 14 and the crushable zone positioned in front of the engine 2 in the narrow engine room 1.

  In the narrow engine room 1, the engine 2 can be mounted compactly in the vehicle vertical direction while having a crushable zone between the hood 13 and the engine 2.

  The engine functional parts can be arranged in the narrow engine room 1 by effectively utilizing the space.

  Furthermore, a space that expands in the vertical direction toward the rear of the vehicle is formed between the engine 2 disposed substantially vertically and the bonnet 13 above the engine 2. The intake pipe length varying device 46 is formed in this space. It is possible to arrange the intake manifold having a compact size.

<< Second Embodiment >>
In the first embodiment described above, the intake manifold 4 having a low-speed intake path and a high-speed intake path is employed, but the present invention is not limited to this. Also, the air cleaner unit 6 can adopt a configuration different from that of the first embodiment. Hereinafter, a second embodiment in which the intake manifold and the air cleaner unit are configured differently from the first embodiment will be described. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, and further description thereof is omitted.

  As shown in FIGS. 7 to 10, the intake manifold 9 according to the second embodiment communicates with four independent intake manifolds 91, 91,..., And the intake manifolds 91, 91,. The intake manifold pipe 95 gathers into one and the intake pipe length variable device 96 that optimizes the charging efficiency of the intake air by switching the intake pipe length according to the rotational speed of the engine 2.

  Each of the intake manifolds 91 is located on the vehicle front side of the engine 2 and communicates with the intake port, and an extending portion 93 that is located above the cylinder head cover 3 and continues to the downstream curve portion 92. And an upstream curved portion 94 that is located on the vehicle rear side and is continuous with the extending portion 93. The first intake manifold 91a, the second intake manifold 91b, the third intake manifold 91c, and the fourth intake manifold 91d are sequentially arranged from the front of the engine, and the corresponding downstream curved portion 92, extending portion 93, and upstream curved portion are provided. The part 94 is also denoted by the same reference signs a to d. Further, the intake manifold 95 is disposed at a position corresponding to a substantially central position between the first intake manifold and the fourth intake manifold in the cylinder row direction on the vehicle rear side of the engine 2. The end of the upstream curved portion 94 communicates with the intake manifold 95.

  The downstream curved portion 92 has the same configuration as that of the first embodiment, is curved on the front side of the vehicle with respect to the engine 2, and is disposed so as to be inclined forward of the engine.

  As shown in FIG. 7, each of the extending portions 93 is offset to the front side of the engine with respect to the spark plug unit 31 erected in the corresponding cylinder, and the spark plug unit 31 and a part thereof are partly viewed from the rear of the engine. It arrange | positions so that it may overlap (refer FIG. 10). At this time, the first extending portion 93a is located between the spark plug unit 31 at the forefront of the engine and the engine oil inlet 3b.

  Further, as shown in FIGS. 9 and 10, the upstream curved portions 94, 94,... Are curved toward the center side in the cylinder row direction of the engine 2 on the vehicle rear side from the respective spark plug units 31. From there, it curves further downward at the vehicle rear portion of the engine 2.

  As shown in FIGS. 7 and 8, the intake collecting pipe 95 has the second and third upstream ends thereof at positions opposite to the second upstream curved portion 94 b and the third upstream curved portion 94 c on the rear side of the engine 2. It arrange | positions in the downward position rather than the curved parts 94b and 94c. As shown in FIGS. 9 and 10, the second upstream curved portion 94b and the third upstream curved portion 94c are connected to the upper portion of the intake manifold 95 from above, and the first upstream curved portion 94a and the fourth upstream curved portion 94c. The curved portion 94d is connected to the upper part from the side of the intake manifold 95 on the vehicle front side of the second upstream curved portion 94b and the third upstream curved portion 94c. By adopting such a configuration, the intake system can be made compact, and the length of each intake manifold 91 is made long and equal to improve the low-speed torque of the engine 2 while filling the cylinder from each intake manifold 91. The efficiency can be made uniform.

  As shown in FIG. 8, a manifold-side fresh air pipe 95a extends in a substantially horizontal direction toward the rear of the engine at the rear portion of the intake manifold 95. The manifold-side fresh air pipe 95a is connected to the throttle valve unit 61g.

  Each of the intake manifolds 41 is disposed so that the rear of the vehicle rises along the forwardly inclined shape of the bonnet 13 as shown in FIGS. 9 and 10, and the intake manifolds 91, 91,. The intake pipe length varying device 96 is disposed in a space formed between the rear side portion and the cylinder head cover 3.

  As shown in FIG. 10, the intake pipe length varying device 96 is arranged between the intake manifold pipe 95 and the spark plug units 31, 31,... An expansion chamber 96a extending in the direction, an opening 96b formed at a substantially central portion in the longitudinal direction of each of the extending portions 93, and the expanding portion 96b passing through the lower side of each extending portion 93. A short pipe portion 96c communicated with the chamber 96a from the front of the vehicle, and an open / close valve 96d disposed in each short pipe portion 96c. Unlike the expansion chamber 46a of the first embodiment, the expansion chamber 96a does not communicate with the intake manifold 95 but communicates only with the short pipe portions 96c. That is, the expansion chamber 96a serves as a communication pipe that allows the extending portions 93 to communicate with each other in the vicinity of the opening portions 96b.

  The opening / closing valve 93d is switched between open and closed according to the rotational speed of the engine 2. Specifically, the opening / closing valve 96d is closed when the rotational speed of the engine 2 is low, while the opening / closing valve 96d is opened when the engine 2 is at a high speed, thereby changing the pressure reversing unit where the basic pressure wave of the intake air is reversed, thereby improving the charging efficiency of the intake air. Optimized.

  Each on-off valve 96d is positioned on the vehicle front side with respect to each spark plug unit 31, and its valve shaft 96e extends in the cylinder row direction of the engine. Therefore, one shaft shaft (not shown) that drives all the on-off valves 96d can be extended in the cylinder row direction while avoiding interference with each spark plug unit 31. Further, by disposing each on-off valve 96d on the vehicle front side with respect to each spark plug unit 31, each opening 96b is necessarily positioned on the vehicle front side with respect to each spark plug unit 31. As a result, the difference in pipe length between the low-speed intake path and the high-speed intake path can be increased, and intake charge efficiency can be optimized for a wide range of engine speeds.

  Further, since the expansion chamber 96a and the intake manifold 95 are concealed by the intake manifolds 91, 91,... In the plan view of the engine, the appearance of the upper surface of the engine 2 is improved even when the engine cover is not provided. .

  Further, each intake manifold 91 is extended from the vehicle front side of the engine 2 to the vehicle rear side by the downstream curved portion 92, the extending portion 93, and the upstream curved portion 94, so that the length of the intake manifolds 91, 91,. The length can be increased, and the low-speed torque of the engine 2 can be improved.

  As shown in FIGS. 7 and 11, the air cleaner unit 10 according to the second embodiment includes an air cleaner case 101 and two resonance chambers 102 and 103 separately formed, and the transmission 25 (not shown). It is integrally arranged above.

  As shown in FIG. 11, the air cleaner case 101 has a lower dusty side chamber 101a and an upper clean side chamber 101b. The dusty side chamber 101a and the clean side chamber 101b are defined by air cleaner elements 101c that are inclined. The clean side chamber 101b has a fresh air outlet 101e on the vehicle rear side.

  The air cleaner element 101c is inclined so that its height decreases toward the rear of the vehicle. For this reason, the area of the air cleaner element 101c in the air cleaner case 101 can be increased. This also increases the height of the clean side chamber 101b toward the rear of the vehicle, and the vehicle rear portion of the clean side chamber 101b is sufficient for disposing the fresh air outlet 101e. Space is reserved.

  The fresh air outlet 101e extends from the rear side of the clean side chamber 101b toward the rear of the vehicle. The upstream end of the air cleaner side fresh air pipe 101f is connected to the fresh air outlet 101e. The downstream end of the air cleaner-side fresh air pipe 101f is curved toward the intake manifold 95 and is connected to the upstream end of the throttle valve unit 61g. On the other hand, the manifold side fresh air pipe 95a is connected to the downstream end of the throttle valve unit 61g.

  Therefore, the manifold side fresh air pipe 95a, the air cleaner side fresh air pipe 101f, and the throttle valve unit 61g are substantially the same height as the intake manifold 9, as shown in FIGS. The total engine height is not increased.

  Further, as shown in FIG. 7, the resonance chamber 102 is adjacent to the front side of the engine of the air cleaner case 101, and a part thereof is formed by offsetting the fourth intake manifold 91d to the front side of the engine. The cylinder head cover 3 is disposed in a space above the cylinder head cover 3 so as to overlap the cylinder head cover 3 in plan view of the engine. The resonance chamber 103 is below the air cleaner side fresh air pipe 101f and adjacent to the vehicle rear side of the clean side chamber 101b. By providing these two resonance chambers 102 and 103, vibrations at two different resonance frequencies can be suppressed.

  Therefore, the fresh air introduced into the dusty side chamber 101a is purified by the air cleaner element 101c and introduced into the clean side chamber 101b. The fresh air taken out from the fresh air take-out port 101e passes from the air cleaner side fresh air pipe 101f through the manifold side fresh air pipe 95a via the throttle valve unit 61g to the intake manifold 95 of the intake manifold 9. It is sent.

  Even if the intake manifold 9 and the air cleaner unit 10 are employed, the engine 2 can be made compact while having a crushable zone in front of and above the engine 2 in the narrow engine room 1 as in the first embodiment. And an intake pipe length varying device can be efficiently arranged.

<< Other Embodiments >>
The present invention may be configured as follows with respect to the first embodiment. That is, the intake manifolds 4 and 9 and the air cleaner units 6 and 10 shown as the first and second embodiments can be freely combined.

  Moreover, in the said 1st Embodiment and 2nd Embodiment, although each said extending part 43 and 93 is offset to the engine front with respect to each spark plug unit 31, it is good also as a structure offset to the engine back.

1 is a plan view showing an engine according to a first embodiment of the present invention. It is a front perspective view of the engine. It is a rear view of the engine. It is a partial cross section figure of an intake manifold. It is a front view of the engine. It is a right view of the same engine. It is a top view which shows the engine which concerns on 2nd Embodiment. It is a rear view of the engine. It is a left view of the same engine. It is a partial cross section figure of an intake manifold. It is a right view of the same engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine room 13 Bonnet 2 Engine 3 Cylinder head cover 31 Spark plug unit 4 Intake manifold 41 Intake manifold 44 Upstream curved part 45 Intake collecting pipe 45a Manifold side fresh air pipe (fresh air pipe)
46 Intake pipe length variable device 46a Expansion chamber (Expansion chamber for variable intake)
46c Short pipe part (short pipe)
46d On-off valve 46e Valve shaft 6 Air cleaner unit

Claims (5)

An in-line multi-cylinder engine intake device mounted horizontally in an engine room of a vehicle such that an intake port is located on the front side of the vehicle and an exhaust port is located on the rear side of the vehicle,
A plurality of intake manifolds extending from the intake port above the cylinder head cover of the engine to the rear of the vehicle, and an intake manifold that communicates with the intake manifold on the vehicle rear side of the engine and gathers together. An intake manifold having an intake pipe length changing device for changing the intake pipe length,
The variable intake pipe length device includes a short pipe communicating with each intake manifold, a variable intake expansion chamber communicating with each intake manifold via the short pipe, and the expansion chamber and each intake manifold communicating with each other. -Having an on-off valve to shut off,
The engine room is defined by a bonnet having a forwardly inclined shape so that the upper surface of the engine room is inclined toward the front of the vehicle so that the ground height decreases.
The engine is arranged substantially vertically,
The intake manifold is disposed at a position above the cylinder head cover so as to be inclined so that the rear of the vehicle becomes higher along the forwardly inclined shape of the bonnet
The engine intake device according to claim 1, wherein the expansion chamber is disposed between a vehicle rear side portion of the intake manifold and the cylinder head cover. The engine intake device according to claim 1,
Each of the intake manifolds is an upstream curved portion whose upstream end is curved downward and communicates with the intake manifold,
The intake system for an engine, wherein the intake manifold and the expansion chamber are arranged in parallel in the vehicle front-rear direction in the rear view of the engine on the vehicle front side with respect to the upstream curved portion. The engine intake device according to claim 1 or 2,
The engine has a spark plug unit that stands upright at the center of each cylinder and protrudes upward from the upper surface of the cylinder head cover,
The expansion chamber is disposed on the vehicle rear side with respect to the spark plug unit, while the on-off valve is disposed on the vehicle front side with respect to the spark plug unit,
An intake device for an engine, wherein a valve shaft of the on-off valve extends in a cylinder row direction of the engine. The engine intake device according to claim 1 or 2,
The engine is an inline 4-cylinder engine,
The first to fourth intake manifolds corresponding to the first to fourth cylinders of the engine are juxtaposed above the cylinder head cover,
The intake manifold pipe is disposed at a position corresponding to a substantially central position between the first intake manifold and the fourth intake manifold in the cylinder row direction, and a fresh air pipe communicating with the air cleaner unit is provided below the intake manifold pipe. Are connected,
Among the four intake manifolds, the second and third intake manifolds corresponding to the second cylinder and the third cylinder have their upstream ends connected to the upper part of the intake manifold pipe from above, The first and fourth intake manifolds corresponding to the cylinder and the fourth cylinder are connected to the front side of the vehicle from the side of the connection portion of the second and third intake manifolds in the intake manifold, respectively.
An intake system for an engine, wherein the lengths of the first to fourth intake manifolds are set to be approximately equal. The intake device for an engine according to any one of claims 1 to 4,
In the engine plan view, each intake manifold is offset in the engine front-rear direction with respect to a spark plug unit that stands in the center of each cylinder and protrudes upward from the top surface of the cylinder head cover. An air intake device for an engine, wherein at least a part of the air intake unit overlaps with each of the spark plug units in the vertical direction.

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