JPH0536014U - Intake / exhaust noise reduction device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a device for effectively canceling intake and exhaust noises of an internal combustion engine. [Structure] A first intake port 15A of the intake pipe 10 that is opened close to the outlet 24A of the exhaust pipe 20, and an outlet 2 of the exhaust pipe 20.
Second intake port 16A of intake pipe 10 opening away from 4A
A switching valve 17 for the amount of intake air sucked from the first suction port 15A and the second suction port 16A, and a control means 18 for operating the switching valve 17 according to the operating state are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an intake / exhaust noise reduction device for an internal combustion engine.

[0002]

[Prior Art]

 In automobiles, etc., as the quietness of the engine body improves. There is an increasing demand for reduction of intake and exhaust noise.

As a countermeasure against this, for example, in Japanese Utility Model Laid-Open No. 63-11379, a microphone and a speaker are attached in the middle of an intake pipe, and a sound pressure signal detected from the microphone and a phase signal from a crank angle sensor are controlled by a control unit. To the speaker to obtain the amplitude and phase of the sound that is in the opposite phase to the intake sound, send this information to the speaker, and the speaker has almost the same amplitude as the intake sound and has the opposite phase. It has been proposed to reduce the intake sound by generating the sound wave of.

Since the intake sound is mainly regarded as a pressure wave caused by pressure pulsation associated with opening and closing of an intake valve, if a pressure wave of the same frequency and an opposite phase can be applied to cancel this pressure wave, It is known that both waves interfere with each other and cancel each other out, weakening the amplitude or sound pressure of the waves.

[0005]

[Problems to be solved by the device]

 In the case of automobile engines, the problem of intake noise or exhaust noise is in the low frequency range of 100 Hz or less, and particularly when resonance occurs in this low frequency range, the vibration is amplified and an uncomfortable muffled sound is produced in the vehicle interior. Can occur.

However, in such a conventional device, since the same sound pressure as the intake sound is created by the speaker, the sound pressure equivalent to the resonance sound generated in the low frequency range of 100 Hz or less in the intake pipe. Is difficult to generate from the speaker, which not only causes an increase in the size of the speaker, resulting in an increase in weight and deterioration of mountability in a vehicle, but also increases power consumption for driving the speaker.

The present invention focuses on the above points, and an object thereof is to effectively cancel the intake and exhaust sounds by utilizing the exhaust pulsation instead of the speaker.

[0008]

[Means for Solving the Problems]

 The present invention is directed to a first intake port of an intake pipe that is opened near an outlet of an exhaust pipe, a second intake port of an intake pipe that is opened apart from an outlet of an exhaust pipe, a first intake port and a second intake port. A switching valve for the amount of intake air sucked in from and a control means for operating the switching valve according to the operating state are provided.

[0009]

[Action]

 When the intake valve and the exhaust valve provided in each cylinder are opened and closed at a predetermined timing in synchronization with the rotation of the crankshaft, pressure waves are generated in the intake pipe and the exhaust pipe, respectively. Both pressure waves have the same frequency, and the intake sound radiated from the first intake port and the exhaust sound radiated from the exhaust outlet are provided so that their phases are opposite to each other. They interfere with each other and cancel each other out, weakening the wave amplitude or sound pressure. At low and medium speeds, the switching valve opens the first intake port, which lowers the sound pressure level of the intake and exhaust sounds, preventing the intake and exhaust sounds from amplifying the muffled sound in the passenger compartment. The noise to the outside can be effectively reduced.

Further, in the high speed range where it is difficult to maintain the opposite phases of the intake pressure wave and the exhaust pressure wave in the entire operating range, and the intake / exhaust sound does not pose a problem, the switching valve causes the switching valve to perform the second intake. The mouth is opened.

[0011]

【Example】

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

As shown in FIG. 1, a vehicle 1 has a four-cylinder engine 2 horizontally mounted in the center thereof, and a rotational force is applied to left and right rear wheels 6 via a transmission 3, a transfer 4, a drive shaft 5, and the like. It is designed to communicate. In the figure, 7 is the left and right front wheels of the vehicle, and 8 is the windshield.

As shown in FIG. 2, the intake pipe 10 of the engine 2 includes an intake manifold 11 communicating with each cylinder 2A via an intake port, an intake duct portion 13 connecting the intake manifold 11 and the air cleaner 14, It is composed of a throttle valve 9 which is provided on the way and adjusts the amount of intake air, and two intake duct portions 15 and 16 which introduce outside air into the air cleaner 14. Each of the intake duct portions 15 and 16 has a first intake port 15A and a second intake port 16A for taking in intake air at the respective tips.

The exhaust pipe 20 is connected to an exhaust manifold 21 that collects exhaust gas discharged from each cylinder 2 A through an exhaust port, an exhaust pipe portion 22 that connects the exhaust manifold 21 and the muffler muffler 23, and the muffler muffler 23. And an exhaust pipe section 24 that operates. An exhaust outlet 24A for discharging exhaust gas to the outside is provided at the tip of the exhaust pipe portion 24.

The first intake port 15A of the intake duct portion 15 is arranged close to the exhaust outlet 24A of the exhaust pipe 20, and the distance between them is the intake sound emitted from the first intake port 15A and the exhaust outlet 24A. The exhaust noise is appropriately set so as to interfere. The first intake port 15A and the exhaust outlet 24A are arranged in parallel to each other in the lateral direction of the vehicle 1, and the first intake port 15A is disposed in front of the vehicle 1 with respect to the exhaust outlet 24A.

The volume of the intake / exhaust system is adjusted so that the intake sound radiated from the first intake port 15A and the exhaust sound radiated from the exhaust outlet 24A have mutually opposite phases centering on the low-medium speed range. Set the pipe length appropriately. Although the pressure wave of the intake pipe 10 and the pressure wave of the exhaust pipe 20 have the same frequency, they have almost opposite phases due to the difference in the opening / closing timing of the intake valve and the exhaust valve. Furthermore, the volume of the muffler muffler 23 is appropriately set so that the intake sound emitted from the first intake port 15A and the exhaust sound emitted from the exhaust outlet 24A are substantially equal in the low and medium speed range.

The second intake port 16A of the intake duct portion 16 is arranged in front of the vehicle 1 with respect to the exhaust outlet 24A so that almost no exhaust gas emitted from the exhaust outlet 24A flows in.

A switching valve 17 is provided in the middle of the intake duct portion 16 in order to switch the amount of air sucked from the first suction port 15A and the second suction port 16A. A control unit 18 composed of a micro computer is provided as a control means, and the control unit 18 inputs the detection signal from the vehicle speed sensor 19 and outputs from the first intake port 15A in the low and medium speed range where intake and exhaust noise becomes a problem. The entire amount of intake air is introduced, and switching is performed so that it is introduced from the second intake port 16A when in the high speed range and when stopped.

With such a configuration, the switching valve 17 is closed by a signal from the control unit 18 in the low and medium speed range, and intake air is taken in through the first intake port 15A.

When the intake valve and the exhaust valve provided in each cylinder 2A are opened and closed at a predetermined timing in synchronization with the rotation of the crankshaft, pressure waves are generated in the intake pipe 10 and the exhaust pipe 20, respectively. Both pressure waves have the same frequency, and the intake sound radiated from the first intake port 15A and the exhaust sound radiated from the exhaust outlet 24A are provided so as to have opposite phases, so that the intake sound and the exhaust sound are generated. Interfere with each other and cancel each other out, weakening the wave amplitude or sound pressure.

The vibration of the rotational secondary component of the engine propagates into the vehicle interior and causes muffled noise. However, by lowering the sound pressure level of the intake and exhaust noise in the low frequency range, the intake and exhaust noise is reduced. Amplification of muffled sound can be prevented and noise outside the vehicle can be effectively reduced.

In addition, the switching valve 17 is opened by the control unit 18 in the high speed range where it is difficult to maintain the opposite phases of the intake pressure wave and the exhaust pressure wave in the entire operating range, and the intake and exhaust noise is not a problem. Then, the intake air is taken in through the second intake port 16A.

Since the exhaust outlet 24A is close to the first intake port 15A, a part of the exhaust gas may flow from the first intake port 15A. However, as shown by the arrow in the figure, the vehicle 1 Since the first intake port 15A is open to the upstream side with respect to the traveling wind flowing around, it is possible to prevent the exhaust gas recirculation amount in the low to medium speed range from increasing.

When there is no running wind, the switching valve 17 is opened by the control unit 18 to prevent exhaust gas from being recirculated to the intake system.

Next, another embodiment shown in FIG. 3 will be described.

The engine 2 is mounted vertically in the rear of the vehicle 1, and the intake pipe 30 has two intake duct portions 35 and 36 for introducing outside air into the air cleaner 34 extending in the left-right direction along the rear end of the vehicle. Each tip has a first suction port 35A and a second suction port 36A for sucking outside air.

The exhaust pipe 40 has an exhaust outlet 44A that discharges exhaust gas to the outside at the tip of an exhaust pipe portion 44 connected to the muffler muffler 43, and the first intake port 35A of the intake duct portion 35 is the exhaust outlet. 44A, the first intake port 35A is directed to the front of the vehicle 1, the exhaust outlet 44A is directed to the rear of the vehicle 1, and the first intake port 35A is located to the front of the vehicle 1 from the exhaust outlet 44A. Is located in.

Then, in the low and medium speed range, the volume of the intake / exhaust system is adjusted so that the intake sound emitted from the first intake port 35A and the exhaust sound emitted from the exhaust output port 44A have opposite phases. Set the pipe length appropriately. Further, the volume of the muffler muffler 43 is appropriately set so that the intake sound emitted from the first intake port 35A and the exhaust sound emitted from the exhaust outlet 44A are substantially equal in the low and medium speed range.

Also in this case, a switching valve that switches between the first suction port 35A and the second suction port 36A is provided to reduce the noise by interfering with the intake and exhaust sounds in the low and medium speed range.

[0030]

[Effect of the device]

 INDUSTRIAL APPLICABILITY As described above, the present invention relates to an intake / exhaust noise reduction device for an internal combustion engine, which includes a first intake port of an intake pipe that is opened near an outlet of an exhaust pipe and an intake pipe that is opened apart from an outlet of an exhaust pipe. Since the second intake port, the switching valve for the amount of intake air sucked from the first intake port and the second intake port, and the control means for operating the switching valve according to the operating state are provided, exhaust pulsation energy is utilized. The intake pulsation can be effectively mitigated and dampened, and vehicle noise can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a vehicle showing an embodiment of the present invention.

FIG. 2 is a plan view of the same engine.

FIG. 3 is a plan view of a vehicle showing another embodiment.

[Explanation of symbols]

 1 vehicle 2 engine 10 intake pipe 15A first intake port 16A second intake port 17 switching valve 18 control unit 19 vehicle speed sensor 20 exhaust pipe 24A exhaust outlet

Claims (1)

[Scope of utility model registration request] 1. A first intake port of an intake pipe opened near an outlet of an exhaust pipe, a second intake port of an intake pipe opened apart from an outlet of an exhaust pipe, a first intake port and a second intake port. An intake / exhaust noise reduction system for an internal combustion engine, comprising: a switching valve for changing the amount of intake air taken in from a mouth; and a control means for operating the switching valve according to operating conditions.