JPH0519567Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a surge tank that is interposed in the intake passage of a vehicle engine and provides a stable supply of intake air.

[Prior Art] Recently, with the spread of electronically controlled fuel injection devices, vehicle engines are equipped with a surge tank between the throttle body and the intake pipe to ensure a stable supply of intake air to each cylinder. There are also quite a few. For example, the surge tank was developed as a prior art of the present invention.
As shown in Japanese Patent No. 59-13334, it is generally formed into a rectangular parallelepiped with an arbitrary volume and mounted parallel to the longitudinal direction of the engine body.
Usually, one end in the longitudinal direction is connected to the throttle body, and one side wall in the direction of the cylinder row is formed with the same number of air outlet ports as the number of cylinders, and each of these outlet ports and the intake port of the engine body are of equal length. The two are communicated via a plurality of intake pipes. In addition, a cold start injector is installed in the surge tank to improve engine starting performance when cold. Inside the intake pipe is an injector, and a delivery pipe that distributes fuel to this injector is approximately parallel to the engine body. It is often placed with

[Problems to be solved by the invention] However, when making multiple intake pipes of equal length,
This may lead to the following inconveniences.

Because control devices such as the throttle body and throttle opening lancer are located at one longitudinal end of the surge tank, the longitudinal dimension of the surge tank may be shorter than the longitudinal dimension of the engine body. Not a few. Therefore, the intake pipe will extend radially from the surge tank toward the engine body. If you simply make the intake pipe the same length in this state, the inside of the intake pipe etc. will be uneven, so the delivery pipe etc. This will cause a problem with the placement. Furthermore, the intake pipe is often formed to be relatively long in order to increase the intake inertia at relatively low rotation speeds and increase the efficiency with which air is filled into the combustion chamber.
However, with such a device, the intake pipe may protrude from the side of the surge tank, so if the side of the intake pipe is uneven, the dimensions between it and the front fender apron, dash panel, etc. will be uneven, and this space will become uneven. Effective use becomes difficult. For the reasons described above, it is preferable that the intake pipes have the same length and are aligned in side view.

On the other hand, it has also been devised to adjust the length of the intake pipe by changing the mounting position of the surge tank, for example by arranging the entire surge tank at an angle.
However, a part of the rich air-fuel mixture caused by the use of a cold start injector used when cold starting an engine or a low-temperature choke valve becomes liquid and may adhere to the bottom wall of the surge tank. Also, when the outside air is cold, water droplets may adhere to the walls inside the surge tank. Therefore, if the surge tank is arranged at an angle, these liquid fuel and water droplets will be guided only from the lower intake pipe to a specific cylinder, which will cause a problem.

An object of the present invention is to provide a surge tank that can relatively easily solve these conventional problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a surge tank connected to an intake port of an engine body via a plurality of intake pipes formed to have equal lengths.
The longitudinal dimension thereof is formed to be shorter than the longitudinal dimension of the engine body, and the side wall on which each of the intake pipes is connected is approached to the engine body at one end side with respect to the crankshaft when viewed from above. and is formed so as to be inclined by being separated from the other end, the bottom wall surface is formed in a substantially horizontal position, and is offset toward one end in the crank axis direction of the engine body, and It is characterized in that the front branch portion of the intake pipe is connected such that the tangent of the outermost portion in plan view is parallel to the crankshaft.

[Function] With this configuration, each intake pipe can be made of equal length without tilting the surge tank vertically with respect to the crankshaft, and the inner side of each intake pipe on the engine body side and The outer sides are aligned.

In addition, since the bottom wall of the surge tank is in a nearly horizontal position, liquid fuel that adheres to the bottom wall when the engine is started at a low temperature, condensed water that adheres to the inner wall when the outside air is cold, etc. It can be uniformly distributed to each cylinder via the intake pipe.

Furthermore, by making the tangent line of the outermost part of the branch part of the front stage of the intake pipe extending from the surge tank parallel to the crank axis, that is, the engine body in plan view, it is connected to the engine body in plan view. The entire intake system becomes more compact. This improves the ease of mounting on a vehicle.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a plan view schematically showing the front part of a riding type vehicle body that employs a front engine/front drive system.

The vehicle 1 shown in the drawings has an engine body 3 placed horizontally in an engine room 2. An exhaust pipe (not shown) is attached to the front end of the engine body 3, and an intake system and the like are installed on the passenger compartment 4 side. A fuel supply device (not shown) such as an injector is provided to mix fuel into the intake system. The air cleaner in the intake system and the throttle body 5 downstream of it are connected to the air hose 6.
A surge tank 7 is connected downstream of the throttle body 5 to enable a stable supply of air to each cylinder. The surge tank 7 has an air inlet 8 opened in an end surface 7c of an end wall 7a.
The side thereof is located on the side of the brake booster 10 fixed to the dash panel 9, and it is arranged slightly parallel to the side opposite to the inlet port with respect to the engine body 3.

Then, connect the surge tank 7 to the engine body 3.
It is connected to the intake port 11 of the cylinder via a plurality of intake pipes 12 for each cylinder, which are formed to have the same length. The intake pipe 12 includes a front part 13 formed integrally with the surge tank 7 and a rear part 14 detachably interposed between the front part 13 and the engine body 3. The front part 13 has an inward surface 13a in the cylinder row direction on the side wall 7b of the surge tank on the side of the dash panel 9.
and branch portions 15 to 18 for each cylinder that extend downward in a curved manner and are arranged in series with side surfaces 13b, which are the outermost portions in plan view, and branch portions that extend from the inlet 8 side. 15 and 16 are relatively steeply curved toward the throttle body 5 in consideration of the positional relationship of the surge tank 7 and the equal length of each intake pipe 12. A tangent line connecting the side surfaces 13b is parallel to the crank axis. Air passages 15a to 18a are formed inside each branch portion 15 to 18 to guide air in the surge tank 7 to each cylinder. One end of these air passages 15a to 18a has a lower end 15b1 to 18b at the lower part of the inner surface of the side wall 7b.
Air outlet ports 15b to 18 opened with 1 aligned.
b, and the other end is opened at an end surface 19a of a series of flanges 19 formed at the lower end of the front stage part 13, and serves as connection ports 15c to 18c communicating with each of the branch parts 20 to 23 of the rear stage part 14.

The rear section 14 interposed between the front section 13 and the engine main body 3 has an upper surface 14a and a lower surface 14.
b, and is composed of branch portions 20 to 23 that curve in a substantially horizontal direction in the mounting position, and air passages 20a to 23a that communicate with each of the air passages 15a to 18a of the front section 13 are formed inside thereof. has been done. One end of each of these air passages 20a to 23a is opened to an end surface 24a of a flange 24 connected to the flange 19 of the front section 13, and the connection port 1
Connection ports 20b to 23b communicated with 5c to 18c
The other end is opened at the end face 25a of the flange 25 connected to the engine body 3, and the intake port 11 is opened at the other end.
Connection ports 20c to 23c lead to. Then, the air passages 15a to 18a of the front part 13 are communicated with the corresponding air passages 20a to 23a of the rear part 14 at the flanges 19 and 24, so that the inside of the surge tank 7 and the intake port 11 are communicated with the same length. ing. In addition, each connection port 20c of the rear part 14~
Openings 26 to 29 formed near 23c are
This is for mounting an injector that injects fuel into the intake port 11.

On the other hand, the surge tank 7 is formed such that a side wall 7b, to which the intake pipe 12 is connected, is inclined in a plan view with respect to a crankshaft 30 disposed within the engine body 3. Specifically, it has a gently curved shape that gradually moves away from the engine main body 3 from the center part to the end wall 7a side, and the surge tank 7 formed on the end wall 7a part toward the engine main body 3 side is arranged non-parallel to the engine main body 3. It has been done. That is, the end wall 7a side is spaced apart from the engine main body 3, and the end wall 7a side opposite to the end wall 7a is arranged close to the engine main body 3, so that the surge tank 7 is arranged relative to the engine main body 3 in a plan view. It is arranged so as to be inclined at. At the same time, the surge tank 7 is connected to the rear section 14 of the intake pipe 12 while being displaced toward one end in the crankshaft direction. The front part 13 of the intake pipe 12 is connected to the side wall 7b located on the side of the dash panel 9, and the flange 25 of the rear part 14 extends from the side wall 7b.
The length of the intake pipe 12 up to the end surface 25a is made equal. In other words, the connection port 20c opens to the end surface 25a of the flange 25 of the rear section 14 from each of the outlet ports 15b to 18b that open to the inner surface of the side wall 7b.
Each air passage 15a to 18a, 20 to 23c
a to 23a are made to have equal lengths. Further, a cold start injector (not shown) for injecting fuel into the surge tank 7 during a cold start is attached to the other side wall 7d on the side of the engine main body 3.

On the other hand, a bottom wall surface 7e orthogonal to the side walls 7b and 7d
is formed so as to be in a substantially horizontal position when the surge tank 7 is installed, and has respective outlet ports 15b to 18 opened in the bottom wall surface 7e and the side wall 7b.
The lower ends 15b1 to 18b1 of b are made to coincide with each other.

According to such a configuration, the air guided from the inlet 8 to the surge tank 7 is transferred to the side wall 7 from each outlet 15b to 18b opened on the inner surface of the side wall 7b.
Air passages 15a to 15a in the intake pipe 12 are formed to have equal lengths, with a front part 13 extending in a curved manner downwards, and a rear part 14 extending from the lower part of the front part 13 toward the engine body 3. 18a, 20a-2
3a and is led to the intake port 11 of the engine body 3.

On the other hand, due to the use of a cold start injector and a choke valve during a cold start, liquid fuel adhering to the wall inside the surge tank 7 or water droplets adhering to the wall inside the surge tank 7 at low temperatures are removed from the bottom wall in a horizontal position. 7e to the bottom wall surface 7e.
The air is guided from the respective outlet ports 15b to 18b whose lower ends 15b1 to 18b1 are aligned with each other to the respective cylinders through air passages 15a to 18a and 20a to 23a in the intake pipe 12.

According to the above configuration and operation, the intake pipe 12
By forming the side wall 7b of the surge tank 7 in which the surge tank 7 is arranged in a row so as to be inclined with respect to the crankshaft 30 in a plan view, it is possible to make the intake pipe 12 the same length without tilting the surge tank 7.
That is, each outlet port 15b to 18b and the intake port 11 of the engine body 3 are connected to each air passage 15a to 18a, 20a to 23a. As a result, the air in the surge tank 7 is guided to each intake port 11 under the same conditions, making it possible to obtain stable output without variations in each cylinder.

In addition, the inner surface 13a and the side surface 13b of the front section 13
Since the upper surface 14a and the like of the rear section 14 are aligned, it is convenient when disposing a delivery pipe, an injector, etc. on the inner surface 13a or upper surface 14a side, and the space between the side surface 13a and the dash panel 9 can be effectively utilized. You can also do that.

Furthermore, the bottom wall surface 7e of the surge tank 7 is in a horizontal position, and the lower ends 15b1 to 18b1 of each outlet 15b to 18b are horizontally aligned with the bottom wall surface 7e, so that the liquid fuel flowing on the bottom wall surface 7e, etc. It becomes possible to allow water droplets, etc. to flow out substantially uniformly from each outlet 15b to 18b, and it is possible to prevent variations in output, etc. in each cylinder.

Although one embodiment has been described above, the present invention is not necessarily limited to the embodiment described above, and it goes without saying that the surge tank and the like are not limited to the shape of the illustrated example.
Furthermore, the intake pipe is not limited to being composed of a front part integrally formed with the surge tank and a rear part located on the engine main body side, but may be integrally formed with equal length.

[Effects of the invention] As detailed above, in the present invention, the side wall of the surge tank is formed so as to be inclined with respect to the crankshaft in plan view, and the bottom wall surface is formed so as to be in a substantially horizontal position. In addition, it is possible to make the plurality of intake pipes equal in length while aligning their side views, and it is also possible to distribute fuel and moisture in the surge tank substantially uniformly to each cylinder. As a result, it is possible to avoid variations in output among the cylinders, and to provide a surge tank that can effectively utilize the vicinity of the intake pipe. Furthermore, since the tangent to the outermost part of the front branch of the intake pipe in plan view is parallel to the crank axis, that is, the engine body, the entire intake system connected to the engine body can be formed compactly. , it is possible to maintain a sufficient distance from other equipment in the engine room, and it can be easily mounted on a vehicle.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention,
Fig. 1 is a plan view schematically showing the front of the vehicle body, Fig. 2 is a plan view of the surge tank and intake pipe, Fig. 3 is a front view of the surge tank and intake pipe, and Fig. 4 is a surge tank and intake pipe. It is a side view of a partial cross section. 1...Vehicle body, 3...Engine body, 7...Surge tank, 7b...Side wall, 7e...Bottom wall surface, 11
... Intake port, 12 ... Intake pipe, 13 ... Front stage section, 14 ... Back stage section, 15a-18a ... Air passage, 15b-18b ... Outlet, 15b1-18
b1...lower end, 20a-23a...air passage, 3
0...Crankshaft.

Claims (1)

[Claim for Utility Model Registration] In a surge tank that is connected to the intake port of the engine body via a plurality of intake pipes formed with equal length, the longitudinal dimension thereof is shorter than the longitudinal dimension of the engine body. the side wall to which the intake pipes are respectively connected is close to the engine main body at one end side with respect to the crankshaft in plan view;
and is formed so as to be inclined by being spaced apart at the other end side, the bottom wall surface is formed in a substantially horizontal position, and the intake pipe is deviated toward one end side in the crank axis direction of the engine body. A surge tank characterized in that the surge tank is connected such that the tangent of the outermost part in plan view of the branch part of the front stage part is parallel to the crank axis.