JPH05163927A - Exhaust device for engine - Google Patents

Abstract

PURPOSE:To prevent occurrence of clogging in both a throttle part and a water charging part by providing the throttle part in the vicinity of the water charging port of a water passage, and enlarging a sectional area of the water charging port than that of the throttle part. CONSTITUTION:When it is judged based on a throttle opening and an engine speed that a control condition is brought about where pressure pulsative conditions in each of the exhaust pipe show unconformity, one or both of a valve motor and a water pump 32 are operated, as required. Water in a water tank 50 is press-fed to a main pipe by the operation of the water pump 32. When the pressure exceeds a set value, the water is branched into bilateral collective pipes, further branched into branch pipes, and finally sent to check valves 24. In case that the water-feeding pressure exceeds a set value, the water is charged from each of water charging pipes 23 to exhaust pipes. A passage sectional area (s) of an orifice 56a of a jet part 56 on the water charging pipe 23 is by far smaller than a passage sectional area S of a water charging port 58. In case that, therefore, the exhaust pressure is increased and exhaust gas enters the water charging port 58, the gas is diffused inside a buffler part 57 losing its pressure, and hard to reach the orifice 56a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended for cooling exhaust gas by injecting it into an exhaust pipe and matching pressure pulsation conditions in the exhaust pipe to improve output reduction in low and medium speed regions of an engine. Exhaust control device.

[0002]

2. Description of the Related Art Such an apparatus is known (see, for example, Japanese Patent Publication No. 2-1965). In this device, a water injection port having a constant passage cross-sectional area is communicatively connected to the inside of the exhaust pipe, and the water injection port and the water tank are connected by a water passage via a water pump.

[0003]

By the way, in the case of such a structure, when the exhaust pressure in the exhaust pipe becomes high, the exhaust gas easily enters the water passage from the water injection port, and as a result, carbon or the like is injected into the water injection port. There was a risk of adhesion and clogging. Therefore, the present invention aims to solve the above problems.

[0004]

In order to solve the above problems, an engine exhaust system according to the present invention is provided with a throttle portion in the vicinity of a water inlet of a water passage, and the passage cross-sectional area of the water inlet is reduced to that of the throttle portion. It is characterized in that it is made larger than the passage cross-sectional area.

[0005]

Since the throttle portion is provided on the inner side of the water inlet of the water passage, it is difficult for the exhaust gas to reach the throttle portion even if the exhaust pressure in the exhaust pipe becomes high. Further, since the passage cross-sectional area of the water injection port is larger than that of the throttle portion, the water injection port is also less likely to be clogged.

[0006]

Embodiment An embodiment will be described with reference to FIGS. FIG. 1 is an enlarged cross-sectional view of the water injection port of the exhaust system, FIG. 2 is a system diagram of the entire exhaust system in a 2-cycle V-type 4-cylinder engine, and FIG. 3 is a main part of a motorcycle equipped with this engine. It is a left side view.

First, in FIG. 3, a head pipe 2 is provided at a front end portion of a main frame 1 which extends obliquely downward and rearward in the front-rear direction. A front wheel 4 is supported at the lower part of the.

The engine 5 is supported below the middle portion of the main frame 1, and the upper end portions of a pair of left and right pivot plates 6 extending in the vertical direction are connected to the rear end portion of the main frame 1. Rear arm 7 on pivot plate 6
Of the main frame 1 is pivotally mounted, and a rear wheel 8 is supported at the rear end of the main frame 1. Reference numeral 9 is a cushion unit.

The engine 5 includes a front left cylinder 10 and a rear left cylinder 11
Form a V-shape due to the same explosion relationship with each other, and although not visible in the figure, the right front cylinder 12 and the right rear cylinder 13 are also provided with the same explosion relationship with each other.

From the left and right front cylinders 10 and 12, exhaust pipes 14 and 15 on the left and right front sides extend below the engine 5 toward the rear of the vehicle body, obliquely cross with the rear arm 7 and bend upward, and the rear end portions are Silencers 16 and 17 on the upper side of the rear wheel 8
Connected to.

Exhaust pipes 18 and 19 on the left and right rear sides extend rearward from the left and right rear cylinders 11 and 13 in a substantially straight line, and the rear ends are connected to silencers 20 and 21 above the rear wheels 8. is doing. In this figure, the exhaust pipe 19 on the right side and the silencer 21 connected thereto are overlapped on the left side and are not visible.

A resonance chamber 22 and a water injection pipe 23 are attached to each exhaust pipe. Upstream side (anti-exhaust pipe side) to the water injection pipe 23
A check valve 24 is attached to the. The check valve 24 is a one-way valve that allows water to pass only in the direction of the water injection pipe 23.

A total of two left branch pipes 25 connected to the respective check valves 24 of the exhaust pipes 14 and 18 on the left side are assembled into a left collecting pipe 27 by a three-port joint 26. The left collecting pipe 27 is collected into the main pipe 30 by the right collecting pipe 28 and the three-port joint 29 which are connected to the right exhaust pipes 15 and 19, respectively, as described later. The main pipe 30 is connected to a water pump 32 via a check valve 31. In addition, from the water injection pipe 23 to the main pipe 3
The passages up to 0 are water passages in the present application.

A water pump 3 is provided at an intermediate portion of the main frame 1.
An ECU 33 for driving and controlling the vehicle 2 is provided.
The ECU 33 controls the throttle opening θ _TH which is an input signal from a known throttle sensor 35 provided in the carburetor 34 and the engine which is an input signal from a known rotation sensor 37 provided in the crank chamber 36. It is performed based on the rotation speed N _E.

The main frame 1 is provided in a pair on the left and right with the head pipe 2 as the apex, the front portion of which is reinforced by a gusset 38 having a box structure, and a pair of left and right pivot plates 6 connected to the left and right rear portions. An upper cross pipe 39 is connected between the upper parts. Since each member is hollow, the left and right main frames 1 communicate with each other by the gusset 38, the pivot plate 6 and the upper cross pipe 39 to form a water tank 50 (see FIG. 2 described later) as a whole.

Further, since the main frame 1 is high in the front and low in the rear, the water supply port 40 is provided near the head pipe 2 and the left pivot plate 6 connected to the left rear end of the main frame 1. On top of the water pump 32
Is installed directly.

A lower cross pipe 41 is also connected between the lower ends of the left and right pivot plates 6. Therefore, when the capacity of the water tank 50 is increased by utilizing the entire insides of the left and right main frames 1 and the pivot plate 6, the lower parts of the left and right pivot plates 6 can be connected by the lower cross pipe 41. ..

Next, referring to FIG. 2, the four exhaust pipes 14,
Resonant chambers 2 of the same structure are provided at 15, 18 and 19, respectively.
2, a water injection pipe 23 and a check valve 24 are provided. The resonance chamber 22 communicates with the inside of the exhaust pipe 14 through the neck portion 42, and in order to open and close this communication portion, for example, a butterfly-type resonance chamber valve 43 is provided (in this figure, only the exhaust pipe 14 is designated by reference numerals), It is opened and closed by the valve motor 44.

A total of two right branch pipes 48 are also connected to the check valves 24 of the right exhaust pipes 15 and 19, and each is connected to the right collecting pipe 28 via a three-port joint 49. Therefore, a group of exhaust pipes 14 and 18 connected to the left and right front and rear cylinders 10 and 11 having the same explosion relationship with each other, and a right and front cylinder 12 having the same explosion relationship with each other,
A group of exhaust pipes 15 and 19 connected to 13 and a total of 2
Those that are divided into groups and have the same ignition timing for each group are connected by the branch pipes 25 or 48.

The water tank 50 to which the water pump 32 is connected is
In the case of this embodiment, the main frame 1 and the like are used as described above. However, it is optional to provide an independent water tank without using the main frame 1 or the like. Reference numeral 51 in the figure is a strainer.

When the ECU 33 determines that the control condition requires adjustment because the pressure pulsation state in each exhaust pipe may be inconsistent in the low / medium speed range,
Based on the throttle opening θ _TH and the engine speed N _E
It is pre-programmed to control the operation of both the water pump 32 and the resonance chamber valve 43 simultaneously or individually. In addition,
The control conditions and the operating methods of the water pump 32 and the resonance chamber valve 43 can be arbitrarily set according to the characteristics of the engine used.

FIG. 1 shows in detail the structure of the water injection pipe 23 provided in the exhaust pipe 14. This structure is the same as that of the water injection pipe 23 provided in each of the other exhaust pipes. The water injection pipe 23 includes a holder 52, a joint pipe 53, and a nozzle 54. Each of the joint pipe 53 and the nozzle 54 has a male screw formed on the outer periphery thereof, and has a cylindrical holder 50.
Engages with a female screw formed on the inner peripheral surface of the.

The holder 52 has a small diameter portion 55 at one end, and this portion is inserted into the wall of the exhaust pipe 14 and is attached to the exhaust pipe 14 by press fitting or welding.

At one end of the joint pipe 53, a jet 56 is provided as a throttle portion provided in the middle of the water passage. The amount of water injection required for cooling is determined by the passage sectional area s of the orifice portion 56a of the jet 56.

The nozzle 54 comprises a large diameter buffer portion 57 and a small diameter water injection port 58. The water injection port 58 penetrates the small diameter portion 55 of the holder 52 and projects into the exhaust pipe 14, and the passage cross sectional area S thereof is larger than the passage cross sectional area s of the orifice portion 56a.

The buffer part 57 is located adjacent to the jet 56 and between the water injection port 58, and a buffer space 59 is formed therein. The passage cross-sectional area S ₁ of the buffer space 59 is larger than both the passage cross-sectional areas S and s of the water injection port 58 and the orifice portion 56a.

A flange 60 is formed on the outer periphery of the middle portion of the joint pipe 53, and a holder 52 is provided with a washer 61.
Is in contact with the protruding end of the. A male screw portion 62 is formed on the outer peripheral portion from the flange 60 to the tip end on the side opposite to the jet 56, and one end of the branch pipe 25 is fitted around this portion and fixed by a lock nut 63.

Next, the operation of this embodiment will be described. First,
In FIG. 2, the ECU 33 uses the throttle opening θ _TH input from the branch pipe 25 and the engine speed N _E input from the rotation sensor 37 to exhaust the exhaust pipes 14, 15, 18 respectively.
When it is determined that the pressure pulsation state in the pressure control valve 19 and the pressure pulsation state in 19 are control conditions that cause inconsistency, a command is issued to operate the valve motor 44 or the water pump 32, or both at the same time, if necessary.

When the valve motor 44 receives a command from the ECU 33, the resonance chamber valve 43 of each resonance chamber 22 is opened,
The inside of the resonance chamber 22 is communicated with the inside of each of the exhaust pipes 14, 15, 18 and 19 and resonates. Therefore, the pressure pulsation state of each of the exhaust pipes 14, 15, 18, and 19 that have become inconsistent is adjusted to a consistent state to prevent output reduction.

When the water pump 32 is activated, the water in the pivot plate 6 is pressure-fed to the main pipe 30, and the water pressure is 31.
When the pressure exceeds the set pressure, the flow into the main pipe 30 occurs and each left collecting pipe 27
And the right side collecting pipe 28, and further branch pipes 25 and 4
It branches to 8 and is finally sent to each check valve 24.

When the water supply pressure exceeds the set pressure of the check valve 24, the water is injected from each water injection pipe 23 through each branch pipe 25 into each exhaust pipe 1.
Water is injected into 4, 15, 17, and 18, and each exhaust pipe 14, 1
By lowering the exhaust gas temperature of Nos. 5, 18 and 19 and lowering the sound velocity, the pressure pulsation state is matched and the output reduction is prevented.

At this time, the water injection pipe 23 is provided with the jet 56, and the passage sectional area s of the orifice portion 56a thereof is much smaller than the passage sectional area S of the water injection port 58. Therefore, even if the exhaust pressure in the exhaust pipe 14 becomes higher than the water injection pressure, and as a result, even if the exhaust gas enters the water injection port 58, it is first diffused in the buffer portion 57 to lower the pressure, and Exhaust gas does not easily reach the orifice portion 56a because the orifice portion 56a is throttled to increase the water injection pressure.

Therefore, it is possible to prevent the orifice portion 56a from being clogged by carbon of the exhaust gas, and the opening degree of the water injection port 58 is expanded more than originally necessary for determining the water injection amount. Therefore, clogging is less likely to occur due to the adhesion of carbon or the like to this portion as well.

In addition, the front exhaust pipe 14 in the same explosion relationship
And 18 and the exhaust pipes 15 and 19 on the right side are the branch pipes 2 respectively.
Since they are connected by 5 and 48, the branch pipe 25 or 48
To both ends of the exhaust pipes 14 and 18 or the exhaust pipe 1 at the same time.
Since exhaust gas pressure is applied from 5 and 19, it becomes difficult for exhaust gas to enter each water injection pipe 23, which also helps prevent the water injection pipe 23 from being clogged, which is advantageous in the case of a multi-cylinder engine. Moreover, the piping can be simplified.

FIG. 4 shows a second embodiment in which the structure of the water injection pipe 23 is slightly modified. In the figure, the same parts as those of the previous embodiment are designated by the same reference numerals, and only necessary parts will be described (the same applies hereinafter).

FIG. 4 is a view similar to FIG. 1. In this example, the nozzle 54 is slightly elongated, and one end thereof has a male screw formed on the outer periphery thereof, and a female member formed on the inner peripheral surface of the holder 50. A jet 56 is engaged with the screw and within the engaged end.

The other end of the nozzle 54 forms a water injection port 58 and projects a little longer into the exhaust pipe 14, and the side wall part is provided with several window holes 64. A female screw portion 65 is formed on the inner circumference of the tip end portion of the water injection port 58, and is closed by fitting a plug 70.

A female screw portion 6 is provided at the middle portion of the side surface of the plug 70.
A male screw portion 71 that engages with the screw 5 is formed.

At the end of the plug 70 facing the jet 56, the axial center portion is a conical tapered surface 72 that projects most in the direction of the jet 56. The extension of the tapered surface 72 passes through the inside of the window hole 64. The inclination angle of the tapered surface 72 can be variously changed as illustrated in the drawing.

The total opening area of each window 64 is much larger than the passage sectional area s of the orifice portion 56a. The passage cross-sectional area of the water injection port 58 is also much larger than the passage cross-sectional area s of the orifice portion 56a.

In this way, the taper surface 72 of the plug 70 allows the directivity to be freely given in the water injection direction, and the water can be diffused into the exhaust pipe 14 in a wider area. The gas cooling efficiency can be improved.

FIG. 5 shows a third embodiment, in which the structure of the nozzle 54 is almost the same as that of the previous embodiment. However, it is characterized in that the water injection port 58 of the nozzle 54 is projected to the vicinity of the center C of the exhaust pipe 14. In this way, the exhaust pipe 14
Water can be poured into the central part of the exhaust gas, and the exhaust gas cooling efficiency can be further increased.

The present invention is not limited to the above-described embodiment, but can be applied to a plurality of cylinders other than a single cylinder or four cylinders, and it does not matter whether it is two cycles or four cycles.

[0044]

According to the present invention, the throttle portion provided in the water passage and the water injection port opening into the exhaust pipe with the passage sectional area larger than the passage sectional area of the throttle portion are provided. Therefore, the nozzle portion has a larger passage cross-sectional area than the throttle portion. Therefore, it is possible to make it difficult for the exhaust gas flowing from the water injection port to reach the throttle portion, and to prevent both the throttle portion and the water inlet port from being clogged with carbon or the like.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part according to a first embodiment.

FIG. 2 is a system diagram of an exhaust device according to the first embodiment.

FIG. 3 is a side view of a main part of a motorcycle to which the first embodiment is applied.

FIG. 4 is an enlarged sectional view of a main part of the second embodiment.

FIG. 5 is a schematic sectional view of an essential part according to a third embodiment.

[Explanation of symbols]

 5 Engine 14 Exhaust pipe 15 Exhaust pipe 18 Exhaust pipe 19 Exhaust pipe 23 Water injection pipe 32 Water pump 33 ECU 54 Nozzle 56 Jet 56a Orifice part 57 Buffer part 58 Water injection port 64 Window hole 70 Plug

Claims (1)

[Claims] 1. An engine exhaust device for pouring water into an exhaust pipe to cool the exhaust gas so as to match a pressure pulsation state in the exhaust pipe to improve output reduction, and a water injection port opening into the exhaust pipe. In the one in which the water tank and the water tank are connected by a water passage via a water pump, a throttle is provided near the water inlet of this water passage, and the passage cross-sectional area of the water inlet is smaller than the passage cross-sectional area of the throttle. Exhaust system for engines characterized by being enlarged.