JP2852688B2 - Engine intake system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an intake device for an engine in which an engine main body is disposed below a seat of a cab-over vehicle or the like.

(Prior Art) Conventionally, in the case of an engine which is disposed vertically below a seat of a vehicle, the shape of an installation space of the engine is limited in relation to a seat, and an intake passage for introducing intake air to the engine body is provided. For forming relatively long so as to obtain predetermined intake characteristics, for example, as seen in Japanese Utility Model Laid-Open No. 61-126072, an air cleaner or the like is arranged on the opposite side to the intake side of the engine body, 2. Description of the Related Art A technique is known in which an intake passage is installed so as to pass above an engine body and connect to an intake side.

(Problems to be Solved by the Invention) However, in the intake device in which the intake passage is arranged from the opposite side passing above the engine body as described above, the engine is arranged below the seat. Due to the relationship, the space in the vertical and horizontal directions is restricted, and the shape of the surge tank, the bending of the intake passage, and the like are restricted, and the flow of intake air is obstructed.

That is, the surge tank having a predetermined capacity disposed in the middle of the intake passage is provided on one side of the engine body due to the length of the independent intake passage connected to each cylinder from the surge tank, simplification of the structure, and the like. It is preferable to arrange the upstream intake passage from the opposite side to the surge tank through the upper part of the engine from the opposite side. In the vicinity of the surge tank, it is necessary to change the direction of the intake passage by 180 degrees, and if the intake flow is disturbed, the intake resistance increases, it is difficult to secure good intake characteristics, and the output performance of the engine is affected Will be given.

In view of the above circumstances, an object of the present invention is to provide an intake device for an engine in which intake resistance is reduced while securing a compact structure.

(Means for Solving the Problems) In order to achieve the above object, an intake device for an engine according to the present invention includes an engine body vertically disposed below a seat of a vehicle,
With respect to the surge tank installed on one side of the engine main body, air is introduced into the surge tank from above the engine main body from the opposite side of the engine main body, and the surge tank is connected to each cylinder of the engine main body. One end of the independent intake passage is opened to the lower surface of the surge tank, and the other side of the surge tank facing one side where the upstream intake passage for introducing the intake air to the surge tank is opened is moved downward from above along the seat. It is configured to be inclined outward toward the outside.

In addition, the upstream intake passage is offset above the center of the surge tank, and is connected to the surge tank by being inclined downward, and further, the front upper surface of the surge tank becomes lower as the front upper side along the seat becomes forward. It is preferable to connect the upstream intake passage obliquely forward as well as to make it inclined as described above.

(Operation) In the intake device as described above, the intake air flowing into the surge tank from the upstream intake passage changes its flow direction downward due to the opposed inclined surface, flows from the opening on the lower surface of the surge tank to the independent intake passage, The intake air is introduced into the engine body without increasing the intake resistance, and good intake performance is ensured by a compact intake structure.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. First
FIG. 2 shows a plan structure of a vertical engine provided with an intake device of one embodiment, and FIG. 2 shows a front structure.

The engine E is provided below the seats S1 and S2 (FIG. 2) of the cab-over type vehicle, and the lower side is the front of the vehicle in the plan view of FIG.

The engine body 1 (in-line four-cylinder engine) has a cylinder head 1b on a cylinder block 1a (see FIG. 2), a head cover 2 is mounted on the cylinder head 1b, and an oil cap 3 is provided on the head cover 2. Have been. The engine body 1 is vertically disposed substantially at the center in the width direction of the vehicle. Above the engine body 1, there are provided a center panel P1 which defines the inside of the vehicle, and seat panels P2 and P3 on both sides of which the seats S1 and S2 are installed. It is arranged. Above sheet panel P
2, P3 are formed to be recessed from the sensor panel P1, and the seat cushion Sc is disposed on the upper part.

In the intake device for supplying intake air to the engine main body 1, an independent intake passage 6 is connected to each cylinder from a surge tank 5 disposed on one side of the engine main body 1 in a front-rear direction. For the surge tank 5, the engine body 1
The upstream intake passage 8 extends from the air cleaner 7 disposed on the opposite side of the
Is connected to the approximate center.

More specifically, the box-shaped air cleaner 7 is disposed apart from the engine body 1 and has an air intake port 7a.
The air flow sensor 11 is disposed at an outflow portion on the upper surface, and an air hose 12 made of plastic or the like and a metal air duct 13 are connected to the air flow sensor 11 in this order. The end of the air duct 13 is connected to a throttle body 15 via a short air hose 14, and each connection is fastened by applying a tightening band 16.

A throttle valve (not shown) is interposed in the throttle body 15, and is opened and closed by operating an accelerator lever 18, and a downstream end thereof is formed in a flange portion formed on an upper portion of one side surface 5 a inside the surge tank 5. 19 inlet 19
has been concluded to a. The intake air distributed in the internal space of the surge tank 5 is introduced into each cylinder through independent intake passages 6 which are respectively connected and opened on the lower surface 5c. Further, an ink ejector 21 is provided at a downstream portion of the independent intake passage 6, and injects and supplies fuel from a fuel pipe 22. 23 is a fuel pressure regulator.

The air duct 13 is cast from a metal that is not affected by the engine temperature during operation, and a bracket 13a extending before and after the air duct 13 is fixedly attached to the head cover 2 of the engine body 1. Also, this air duct
An idle passage 25 that supplies intake air at idle to the surge tank 5 from the throttle bypassing the throttle body 15.
Is connected. That is, one end of a rubber pipe constituting the idle passage 25 is connected to a downstream end portion of the air duct 13, and the other end is connected to an inlet of an ISC valve 28 for adjusting an idle air amount. The ISC valve 28 is mounted on the mounting portion 20 on the side of the surge tank 5, and the air whose flow rate has been adjusted is supplied into the surge tank 5.

An upstream blow-by gas passage 32 is connected to the air duct 13, and the upstream blow-by gas passage 32 is
One end is open in the head cover 2 and the other end is an air duct 13.
The connection opening is provided at the upstream side of the connector. A downstream blow-by gas passage 33 is connected to the head cover 2. One end of the downstream blow-by gas passage 33 is connected to a pressure valve 34 (PCV) disposed on the head cover 2, and the other end is directly connected to the surge tank 5.

A seal member 35 is provided in the middle of the upstream side intake passage 8 in order to shut off the thermal influence of the exhaust system of the engine E on the air cleaner 7 side.

The surge tank 5 and the independent intake passage 6 are integrally formed as an intake manifold, and the detailed structure is also shown in FIGS. 3 and 4. In a surge tank 5 extending in a box shape in the longitudinal direction of the engine body 1, an upstream end opening 6a of an independent intake passage 6 is formed in a semi-elliptical shape at a predetermined interval on a lower surface 5c.

Further, a flange portion 19 to which the throttle body 15 is connected is formed at a substantially central portion of one side surface 5a extending in the longitudinal direction of the surge tank 5, as a connection portion of the upstream intake passage 8. An inlet 19a is opened in the flange portion 19, and the center of the inlet 19a is formed to be offset upward from the vertical center of the surge tank 5 (see FIG. 3). From the opening of the upper surface of the surge tank 5
An auxiliary wall 5e is formed to project obliquely at d, forming an introduction portion. A mounting portion 20 for an ISC valve 28 is formed at the rear of one side surface 5a where the flange portion 19 is formed.
Supply port 20 for the surge tank 5 in the idle passage 25
a is formed in a non-circular shape.

On the other hand, the upper half of the other side surface 5b opposite to the one side surface 5a on which the flange portion 19 of the surge tank 5 is formed corresponds to the curved shape of the seat panel P2, and goes from top to bottom. It is formed on an upper slope 5f that is inclined outward, and is formed so that inflow air from the upstream-side intake passage 8 flows downward along the auxiliary wall 5e and the upper slope 5f.

The rear portion of the other side surface 5b is provided with a supply port 20 of the idle passage 25.
A portion facing a is formed on a rear slope 5g that is inclined so as to approach one side surface 5a, and the internal space of this portion is narrowed,
The idle air flowing from the supply port 20a flows forward along the rear slope 5g.

Further, the flange portion 19 on the upper surface 5d of the surge tank 5
The more forward portion is formed on a front slope 5h that is inclined so as to become lower toward the front in relation to the seat panel P2 disposed above.

Further, the shape of the flange portion 19 of the surge tank 5 is such that the center line of the upstream intake passage 8 to be connected is the inclination angle α in FIG.
And slightly inclined forward so as to correspond to the inclination β in FIG. A connection hole 38 for taking out intake negative pressure is opened in the front end face. Reference numeral 39 denotes a sand hole for casting, and reference numeral 40 denotes a connection hole for the downstream blow-by gas passage 33.

The independent intake passage 6 is formed to be curved forward from one end of the lower surface of the surge tank 5, the other end is connected to a mounting flange 17 for the cylinder head 1b, and a substantially oval downstream end opening 6b is formed. At the downstream end of the independent intake passage 6, an ink injector mounting portion 6c is formed. Reference numeral 42 denotes a stay for reinforcement, and reference numeral 43 denotes a cooling water circulation passage attached to the mounting flange 17.

According to the above-described embodiment, the formation of each slope of the surge tank 5 and the setting of the inflow of the upstream side intake passage 8 as described above avoid interference with the seat S1 and suppress each cylinder while increasing the intake resistance. The distribution of intake air is ensured. That is, the upstream-side intake passage 8 is slightly inclined downwardly and offset upward, and the direction of the inflowing air smoothly changes along the upper inclined surface 5f toward the opening of the lower surface 5c. In addition, the upstream space 8 is slightly deflected and connected by the upstream side intake passage 8 because the front space is narrow and the flow of intake air decreases due to the front slope 5h. The distribution of flow rate is equalized.

Further, the connection position of the upstream intake passage 8 to the surge tank 5 is offset upward, and the connection position is slightly inclined downward, so that the intake of the blow-by gas introduced into the upstream intake passage 8 by the upstream blow-by gas passage 32 is performed. Backflow to the upstream side is prevented. Further, by increasing the connection position of the idle passage 25 with respect to the air duct 13 (upstream intake passage 8), the idle passage 25
It is arranged to prevent the oil component in the blow-by gas from flowing into the inside.

(Effects of the Invention) According to the present invention as described above, the independent intake air is introduced into the surge tank installed on one side of the engine main body from above the engine main body from the opposite side of the engine main body. One end of the passage is opened at the lower surface of the surge tank, and the other side opposite to one side where the upstream intake passage is opened is inclined outward from the upper side to the lower side along the seat, so that the upstream side is formed. The intake air flowing from the intake passage into the surge tank is turned downward by the opposite inclined surface, and flows smoothly from the opening on the lower surface of the surge tank to the independent intake passage to supply intake without increasing intake resistance. Therefore, even if the engine is arranged below the seat, it is possible to secure good intake performance while configuring the intake structure to be compact.

[Brief description of the drawings]

FIG. 1 is a plan view of an engine having an intake device according to an embodiment of the present invention, FIG. 2 is a schematic front view of an engine partially omitted, such as a fuel system, FIG. 3 is a side view of an intake manifold, FIG. 4 is a plan view of the same. E ... engine, S1, S2 ... seat, 1 ... engine body, 5 ... surge tank, 5a ... one side, 5b ... other side, 5c ... bottom surface, 5d ... top surface, 5f ... top Slope, 5g Rear slope, 5h Front slope, 6 Independent intake passage, 8 Upstream intake passage, 15 Throttle body, 19 Flange, 19a Inlet.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Araki 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (72) Inventor Kazuo Iwata 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Incorporated (72) Inventor Ujishima Uji 3-1, Fuchu-cho, Aki-gun, Hiroshima Pref. Inside Mazda Co., Ltd. (56) References Japanese Utility Model Sho 55-135148 (JP, U) (JP, U) Real opening Sho 61-39431 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02M 35/16

Claims (4)

(57) [Claims] An engine body is disposed vertically below a seat of a vehicle, and a surge tank is provided on one side of the engine body. In an intake device for an engine that introduces intake air, one end of an independent intake passage that connects from the surge tank to each cylinder of the engine body is opened at a lower surface of the surge tank, and an upstream intake passage that introduces intake air into the surge tank is provided. An intake device for an engine, wherein the other side surface of the surge tank facing one opening side surface is inclined outward from the upper side to the lower side along the seat. 2. An intake system for an engine according to claim 1, wherein said upstream intake passage is connected so as to be offset above a center of said surge tank. 3. An intake system for an engine according to claim 1, wherein said upstream intake passage is inclined downward and connected to a surge tank. 4. The system according to claim 1, wherein the upper surface of the surge tank is inclined so as to become lower toward the front along the seat, and the upstream intake passage is connected obliquely toward the front. An intake device for an engine as described.