JPH04175412A - Control type muffler - Google Patents

Abstract

PURPOSE:To improve both silencing performance with the alteration of effective length of a resonance chamber head and air output with the reduction of exhaust pressure by providing the resonance chamber head joining to an exhaust draining path and a variable control valve for altering the exhaust path to a joining position of the resonance chamber head. CONSTITUTION:When an engine 1 is in a low speed rotation region, a veriable control valve 8 is closed and a first resonator pipe 7 provided in a partition wall 13 between an expansion chamber 4 and a resonance chamber 5 and a second resonator pipe 6 having an exhaust port 6a are both operated. Thus, the resonance frequency of the resonance chamber 5 appears in the low frequency region and the exhaust sound of the low frequency is reduced by a resonance effect. On the other hand, when the engine 1 is in the high speed rotation region, veriable control valve 8 is opened, only the first resonator pipe 7 is operated as a resonance chamber head and the second resonator pipe 6 is operated as an exhaust draining path. Thus, the resonance frequency of the resonance chamber 5 appears in an intermediate frequency region and the exhaust sound of the intermediate frequency is reduced by a resonance effect. And exhaust resistance is reduced by adding a path including the second resonator pipe 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a controlled muffler that is applied to a vehicle having an internal combustion engine and is capable of controlling changes in silencing performance.

(Prior Art) Conventionally, controlled muffs for muffling internal combustion engines have been used.
For example, a device described in Japanese Utility Model Application Publication No. 61-110818 is known.

This conventional source includes a variable length neck portion that faces an exhaust gas introduction passage from an internal combustion engine, and a resonance chamber that communicates with the exhaust gas introduction passage via the variable length neck portion, and detects the rotational speed of the internal combustion engine. , a device is shown in which the length of the variable length neck portion is controlled in accordance with the detected engine rotational speed, and the resonance frequency of the resonance chamber is changed to perform muffling.

(Problem to be Solved by the Invention) However, in such a conventional control type muffler, although the length of the variable length neck of the resonance chamber is changed, the exhaust gas from the outside air introduction passage to the exhaust exhaust passage is Since the path is always a constant path, there is a problem in that the exhaust resistance cannot be changed depending on the engine rotation speed.

In particular, when the engine rotation speed is high, the exhaust resistance cannot be actively reduced, and the exhaust pressure in the exhaust path increases, resulting in a decrease in the output of the internal combustion engine.

The present invention focuses on the above-mentioned problems and provides a control type muffler having a resonance chamber neck, which improves the silencing performance by changing the effective length of the resonance chamber neck and improves the output of the internal combustion engine by reducing the exhaust pressure. The challenge is to balance this with the improvement of

(Means for Solving the Problems) In order to solve the above problems, the control type muffler of the present invention includes at least one resonance chamber neck portion that merges with the exhaust exhaust passage, and the merging position of the resonance chamber neck portion. A variable control valve is installed to change the exhaust route depending on the engine speed.

That is, an expansion chamber and a resonance chamber defined inside the muffler main body, an exhaust gas introduction passage from the internal combustion engine that opens into the expansion chamber, an exhaust exhaust passage that opens into the expansion chamber, and the expansion chamber. a first resonance chamber neck provided with one partition wall with the resonance chamber; a second resonance chamber neck passing through the resonance chamber and having an exhaust port opening into the resonance chamber; and the second resonance chamber neck and the exhaust. A variable control valve which is connected to the exhaust passage and is provided at a merging position on the neck side of the second resonance chamber, and variable control valve opening/closing control means for controlling opening and closing of the variable control valve according to the rotational speed of the internal combustion engine. It is characterized by having

(Function) For example, the variable control valve opening/closing control means closes the variable control valve when the rotational speed detection value from the rotational speed detection means is in a low rotational speed range below the rotational speed setting value, and closes the variable control valve when the rotational speed is higher than the set rotational speed. The operation will be explained using an example of control in which control is performed to open the variable control bulk when the rotational speed is in a high rotational speed range.

When the rotational speed of the internal combustion engine is in a low rotational speed range, the variable control valve is closed, so that the first resonance chamber neck provided on the wall between the expansion chamber and the resonance chamber and the second resonance chamber having an exhaust port are closed. Together with the chamber neck, the resonant frequency of the resonant chamber is in the low frequency range, and low frequency exhaust noise is reduced by the resonance effect.

When the rotational speed of the internal combustion engine is in a high rotational speed range, the variable control valve is opened, so only the first resonance chamber neck provided on the wall between the expansion chamber and the resonance chamber acts as the resonance chamber neck. A second resonant chamber neck with an exhaust port acts as an exhaust outlet passage.

Therefore, the resonant frequency of the resonant chamber is in the medium and high frequency range, and the exhaust noise in the medium and high frequencies is reduced by the resonance effect. Exhaust resistance is reduced by adding a path leading to the exhaust exhaust passage via the second resonance chamber neck.

(Example) Embodiments of the present invention will be described below based on the drawings.

First, the configuration will be explained.

FIG. 1 is an overall system diagram showing a controlled muffler according to an embodiment of the present invention applied to an automobile, and FIG. 2 is a perspective view showing the controlled muffler according to the embodiment.

The controlled muffler of the embodiment includes an expansion chamber 4 and a resonance chamber 5 defined inside a muffler body 12, an exhaust gas introduction passage 2 from an engine 1 (internal combustion engine) opened to the expansion chamber 4, and the An exhaust discharge passage 3 opened to the expansion chamber 4, a seventh resonator pipe 7 (first resonance chamber neck) provided in the partition wall 13 between the expansion chamber 4 and the resonance chamber 5, and a seventh resonator pipe 7 that penetrates the resonance chamber 5 and , a second resonator pipe 6 (second resonance chamber neck) having an exhaust port 6a opening into the resonance chamber 5,
The second resonator vibe 6 joins the exhaust discharge passage 3 at a position outside the muffler body 12.

A variable control valve 8 provided at a confluence position on the second resonator vibro side of the confluence with the exhaust exhaust passage 3, an actuator 11 for opening and closing the variable control valve 8, and an actuator 11 for controlling the rotational speed of the engine 1. The engine rotation sensor 9 (rotation speed detection means) to detect and the engine rotation speed (rotation speed detection value) from the engine rotation sensor 9
A controller 10 (variable control valve opening/closing control means).

Next, the effect will be explained.

FIG. 3 is a flowchart showing the flow of the valve opening/closing control operation performed by the controller 11, and each step will be explained below.

In step 30, the engine rotation speed N detected by the engine rotation sensor 9 provided in the engine 1 is read.

In step 31, it is determined whether the engine rotational speed read by the valve 30 is lower or higher than the set rotational speed 200 Orρm, which is the opening/closing switching threshold of the variable control valve 8.

When N is <200 ρm, the process proceeds from step 31 to step 32. In step 32, a valve closing signal is output to the actuator 11, and in step 33, the actuator 11 that receives the valve closing signal operates to perform variable control. Valve 8 is closed.

Further, when N6≧2000 rpm, the process proceeds from step 31 to step 34, in step 34, a valve opening signal is output to the actuator 11, and in step 35
In response to the valve opening signal, the actuator 11 operates and the variable control valve 8 is opened.

That is, in the controller 10, the engine rotation speed N6 from the engine rotation sensor 9 is the set rotation speed 2000ra.
When in the low rotation speed range below rp, the variable control valve 8
Valve opening/closing control is performed in which the variable control valve 8 is closed and the variable control valve 8 is opened when the rotation speed is in a high rotation speed range of the set rotation speed i2000 rpm or more.

Next, the operation of the variable control valve 8 will be explained separately at 4 o'clock when the valve is closed and when the valve is open.

- (a) When the valve is closed When the rotational speed of the engine 1 is in the low rotational speed range, the variable control valve 8 is closed, so as shown in FIG.
The second resonator vibrator 6 provided on the partition wall 13 between the expansion chamber 4 and the resonance chamber 5 and the second resonator vibro having the exhaust port 6a act together, and the resonant frequency of the resonance chamber 5 is in a low frequency range. Low frequency exhaust noise is reduced by the resonance effect.

Note that the exhaust route is a route from the exhaust introduction passage 2 to the exhaust discharge passage 3 via the expansion chamber 4.

(b) When the valve is open When the rotational speed of the engine 1 is in the high rotational speed range, the variable control valve 8 is opened, so that the expansion chamber 4 and the resonance chamber 5 are separated from each other as shown in FIG. Only the second resonator pipe 6 provided on the wall 13 acts as a resonance chamber neck, and the second
The resonator vibro acts as an exhaust discharge passage.

Therefore, the resonance frequency of the resonance chamber 5 is in the middle frequency range, and the middle frequency exhaust noise is reduced by the resonance effect.

In addition, the exhaust route includes a route from the exhaust introduction passage 2 to the exhaust discharge passage 3 via the expansion chamber 4 and the exhaust discharge passage 3 via the expansion chamber 4 and the second resonator pipe 6. This reduces exhaust resistance.

As explained above, in the control type muffler of the embodiment, the following beneficial effects can be obtained.

■ Second resonator pipe 6 that joins the exhaust discharge passage 3
Since a variable control valve 8 is installed at the confluence position of the second resonator vibro to change the exhaust path according to the engine rotational speed N, the effective length of the resonator pipe can be changed to improve silencing performance and reduce exhaust pressure. Therefore, it is possible to simultaneously improve the output of the engine 1 due to the above.

That is, with regard to improving the silencing performance, by changing the resonance frequency of the resonance chamber 5, it is possible to reduce the pulsating components of the exhaust discharge sound in a plurality of frequency ranges.

For example, Figure 6 shows the experimental results of the sound pressure level of the exhaust discharge sound of the engine rotation secondary component (medium frequency range) when the variable control valve 8 is opened. Be looked at.

In addition, regarding the improvement of engine output, variable control valve 8
Since it is configured to reduce exhaust resistance by opening, engine output increases as exhaust pressure decreases.

For example, FIG. 7 shows the experimental results of exhaust pressure characteristics and engine output characteristics when the variable control valve 8 is opened, and it is clear from the experimental results that exhaust pressure reduction and engine output improvement are achieved.

■ The confluence position of the second resonator vibro and the exhaust discharge passage 3 is located outside the muffler body 12, and the variable control valve 8 is provided on the second resonator vibro side of this confluence. Variable control valve 8 that is less affected by exhaust heat and has lower heat resistance than when installed inside the remuffler body 12, which is directly installed in the main body 12.
It is possible to use the actuator 11, and it is easy to assemble, which is advantageous in terms of cost, and also increases the degree of freedom in attaching the actuator 11.

Although the embodiment has been described above based on the drawings, the specific configuration is not limited to this embodiment.

For example, in the embodiment, an example is shown in which one each of the second resonator pipe and the second resonator vibe is provided, but an example in which two or more resonator pipes are provided may be used.

In addition, in the embodiment, a control example was shown in which the variable control valve is controlled to open and close in an ON-OFF manner depending on the engine rotation speed, but for example, in a rotation speed range of around 2000 rpm, the variable control valve is The control may be such that the valve opening degree is gradually increased.

(Effects of the Invention) As described above, in the present invention, in a controlled muffler having a resonance chamber neck, at least one resonance chamber neck is provided which joins an exhaust exhaust passage, and the resonance chamber neck A variable control valve that changes the exhaust path according to the engine rotational speed is installed at the convergence position of the engine, which improves silencing performance by changing the effective length of the neck of the resonance chamber, and improves the output of the internal combustion engine by reducing exhaust pressure. This has the effect of being able to do this.

[Brief explanation of drawings]

Fig. 1 is an overall system diagram showing a controlled muffler according to an embodiment of the present invention, Fig. 2 is a perspective view showing a controlled muffler according to an embodiment, and Fig. 3 is a flowchart showing the flow of valve opening/closing control operations performed by a controller. , Fig. 4 is an explanatory diagram showing the flow of exhaust gas when the valve is closed, Fig. 5 is an explanatory diagram showing the flow of exhaust gas when the valve is open, and Fig. 6 is the secondary component of engine rotation with respect to engine speed. FIG. 7 is a sound pressure level characteristic diagram of exhaust discharge sound, and FIG. 7 is a diagram showing exhaust pressure characteristics and engine output characteristics with respect to engine rotation speed. 1... Engine (internal combustion engine) 2... Exhaust introduction passage 3... Exhaust discharge passage 4... Expansion chamber 5... Resonance chamber 6... Second resonator pipe (second resonance chamber neck) 6a...Exhaust port A...First luzonator pipe (first resonance chamber neck) 8...Variable control valve 9...Engine rotation sensor (rotational speed detection means) 10...Controller (valve opening/closing control means) 11... Actuator 12... Muffler body 13... Painting wall

Claims (1)

[Scope of Claims] 1) An expansion chamber and a resonance chamber defined inside the muffler body; an exhaust gas introduction passage from an internal combustion engine that opens into the expansion chamber; and an exhaust discharge passage that opens into the expansion chamber. a first resonance chamber neck provided on a wall between the expansion chamber and the resonance chamber; a second resonance chamber neck having an exhaust port penetrating the resonance chamber and opening into the resonance chamber; and the second resonance chamber. a variable control valve that joins the chamber neck and the exhaust exhaust passage and is provided at a merging position on the side of the second resonance chamber neck; and a variable control valve that controls opening and closing of the variable control valve according to the rotational speed of the internal combustion engine. A controlled muffler characterized by having an opening/closing control means and the following.