JP2005061339A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of reducing blurring sound or unpleasant vibration inside a cabin by reducing intake pulsation. <P>SOLUTION: In this internal combustion engine 1, an air compressor 5 is provided. An air intake port 6a in the air compressor 5 is provided between an air cleaner 4 for an intake tube 2 in the internal combustion engine 1 and an intake manifold 8. The air compressor 5 is driven in such a way that pressure waves of intake pulsation B generated by the air compressor 5, at a prescribed frequency, make the inverse phase to that of pressure waves of intake pulsation A by the internal combustion engine 1 at the same frequency Fa. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine that can reduce intake air pulsation.

  In an internal combustion engine (engine) such as a 4-cylinder or a 6-cylinder mounted on a vehicle, as shown in FIGS. 2 and 3 (in the case of 6 cylinders), mainly due to pressure fluctuations accompanying opening and closing of the intake valve, While the crankshaft of the internal combustion engine makes one revolution, intake pulsation of about 2 to 3 times mainly caused by the operation of the intake valve occurs, and a specific frequency (for example, around 90 Hz) of the intake pulsation is generated. When the passenger compartment resonates and resonates with the intake pulsation, a booming noise or unpleasant vibration in the passenger compartment is caused.

  In this case, since it is often difficult to change the dimensions of the passenger compartment, it is necessary to reduce this resonance and the intake pulsation at the resonating frequency. For this reason, an active silencer has been proposed in which a microphone is attached in the middle of the intake pipe and a pressure wave is generated from a speaker according to operating conditions to attenuate the pressure wave generated in the intake pipe by interference.

  In these apparatuses, the frequency, amplitude, and phase difference are set by the sound wave characteristic setting means (see, for example, Patent Document 1), and an enclosure that defines a back chamber having a predetermined volume is provided behind the speaker. By providing a resonance pipe communicating the chamber and the intake pipe, forming the resonance pipe with a predetermined cross-sectional area and passage length, and substantially matching the resonance frequency of the intake pipe and the resonance pipe in a predetermined low frequency range, A pressure wave having a phase opposite to that of pulsation is guided to the intake pipe to cause interference (for example, see Patent Document 2).

  On the other hand, in large vehicles, as shown in FIG. 1, many internal combustion engines are equipped with air compressors for air assist such as brakes, transmissions, suspensions, etc., and this air compressor 5 is driven by a crankshaft of the internal combustion engine 1. The air intake 6 a of the air compressor 5 is provided between the air cleaner 4 and the intake manifold 8 in the intake passage 2.

  Since the air compressor 5 is normally operated at a half speed of the rotation of the internal combustion engine 1, the intake pulsation D is as shown in FIG. Therefore, the intake pulsation D overlaps with the intake pulsation A mainly generated by the operation of the intake valve as shown in FIG. 3 to become the intake pulsation E as shown in FIG.

The present inventor makes the frequency of the pressure wave of the intake pulsation by the air compressor the same as the frequency of the pressure wave of the intake pulsation of the internal combustion engine mainly caused by the intake valve operation, and causes the phases to interfere with each other. Thus, it has been thought that the intake air pulsation of the internal combustion engine can be reduced.
Japanese Patent Application Laid-Open No. 08-14128 JP 05-106524 A

  An object of the present invention is to provide an internal combustion engine that can reduce the intake pulsation of the internal combustion engine, and can reduce the humming noise and unpleasant vibrations in the vehicle interior.

  In order to achieve the above object, an internal combustion engine of the present invention is an internal combustion engine provided with an air compressor, wherein an air intake port of the air compressor is provided between an air cleaner of an intake pipe of the internal combustion engine and an intake manifold. The air compressor is driven so that the pressure wave of the intake pulsation generated by the air compressor has an opposite phase at a predetermined frequency and the same frequency as the pressure wave of the intake pulsation of the internal combustion engine. With this configuration, the pressure wave of the intake pulsation mainly due to the operation of the intake valve of the internal combustion engine at a predetermined frequency that resonates and resonates with the passenger compartment and causes a loud noise or unpleasant vibration in the passenger compartment. The intake pulsation is reduced by the interference of the pressure wave, and the entire intake pulsation is reduced.

  In this internal combustion engine, the air compressor is driven by the crankshaft of the internal combustion engine. This configuration makes it possible to drive the air compressor at the same frequency as the pressure wave of the intake pulsation mainly due to the operation of the intake valve. The frequency can be matched with the frequency of the pressure wave of the intake pulsation of the internal combustion engine.

  According to the internal combustion engine of the present invention, the air intake port of the air compressor is provided in the intake pipe of the internal combustion engine, and the frequency of the pressure wave of the intake pulsation generated by the air compressor is mainly determined by the intake valve operation. Since the frequency of the pulsation pressure wave is the same and the phase is reversed, the intake pulsation of the internal combustion engine as a whole can be reduced by interference between these intake pulsation pressure waves. It is possible to reduce indoor noise and unpleasant vibration.

  Hereinafter, an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of an internal combustion engine 1 according to an embodiment of the present invention. This internal combustion engine (engine) 1 is provided with an air cleaner 4 and an air compressor 5 in an intake pipe (intake passage) 2. An air intake 6a of the air compressor 5 is provided on the downstream side of the air cleaner 4. After the air A is purified by the air cleaner 4, the air Ac is branched and enters the air compressor 5 from the air compressor suction pipe 6 and is compressed. After being supplied to an air tank (not shown) via an air compressor discharge pipe 7 and stored in the air tank, it is supplied to a portion requiring air such as an air brake, a transmission, an air spring suspension, etc. . Here, 3 is an exhaust pipe, and 9 is a transmission.

  The air compressor 5 is constituted by, for example, a reciprocating type (piston type) compressor having a discharge capacity of 400 cc to 700 cc, and is driven by the driving force of the crankshaft of the internal combustion engine 1 by gear driving. When the internal combustion engine 1 has four cylinders, the engine is driven at a double speed relative to the engine rotation, and when the internal combustion engine 1 has six cylinders, the engine is driven at a triple speed. If the air compressor 5 is small, belt drive may be used, but it is necessary to prevent the phase from shifting.

  3 to 7 show the case where the internal combustion engine 1 has 6 cylinders. In this case, as shown in FIG. 2, the crank angle (crank angle) of the crankshaft is one rotation of 0 ° to 360 °. In the meantime, gears and the like are combined so that the air compressor 5 rotates three times. That is, the frequency Fa of the pressure wave of the intake pulsation (intake pressure fluctuation) A is three times the engine rotation frequency Fe here, so the frequency Fb of the pressure wave of the intake pulsation B is also three times the engine rotation frequency Fe. In this way, the number of gear teeth is combined.

  With this configuration, the air compressor 5 can be driven at the same frequency as the pressure wave frequency Fa of the intake pulsation A mainly caused by the operation of the intake valve, so that the intake pulsation generated by the air compressor 5 can be very easily performed. The frequency Fb of the pressure wave B can be matched with the frequency Fa of the pressure wave of the intake air pulsation A of the internal combustion engine 1.

  As a result, the air compressor 5 is changed from the conventional ½ times speed to the 3 times speed, and the increase in the frequency Fb increases the amount of discharge per unit time. Reduce the capacity to be. Due to the reduction in the capacity, the magnitude of the intake pulsation B by the air compressor 5 becomes substantially the same as the magnitude of the intake pulsation A resulting from the operation of the intake valve.

  Further, the phase difference between the pressure wave of the intake pulsation A and the pressure wave of the intake pulsation B at a specific frequency that resonates with the passenger compartment, particularly at a frequency that causes a humming noise or unpleasant vibration in the passenger compartment. However, the phase difference between the crankshaft of the internal combustion engine 1 and the drive shaft of the air compressor 5 and the air intake of the air compressor suction pipe 6 are adjusted so that the intake pipe 2 has an opposite phase, that is, a 180 ° difference. Either the installation position of the inlet 6a, the pipe length L of the air compressor suction pipe 6, or a combination thereof is adjusted. The phase difference between the crankshaft of the internal combustion engine 1 and the drive shaft of the air compressor 5 can be adjusted by shifting the gear meshing position.

  With the above configuration, an intake pulsation B by the air compressor 5 as shown in FIG. 4 is generated with respect to the intake pulsation A resulting from the operation of the intake valve as shown in FIG. When the pressure wave of the intake pulsation B overlaps the pressure wave of the intake pulsation A, the intake pulsation C as shown in FIG. Since the intake pulsation C is a pulsation formed by interference between the pressure wave of the intake pulsation B and the opposite phase of the intake pulsation B at the same frequency Fa as the pressure wave of the intake pulsation A, the amplitude thereof becomes small. Therefore, the intake pulsation C as a whole of the internal combustion engine 1 can be reduced to reduce the humming noise and unpleasant vibrations in the passenger compartment.

It is a block diagram of the internal combustion engine of embodiment of this invention. It is a figure which shows the relationship between a crank angle and a TDC pulse. It is a figure which shows the relationship between a crank angle and intake pressure (intake valve action | operation). It is a figure which shows the relationship between the crank angle and intake pressure (air compressor operation | movement) regarding the internal combustion engine of embodiment of this invention. It is a figure which shows the relationship between the crank angle and intake pressure (intake valve action | operation + air compressor action | operation) regarding the internal combustion engine of embodiment of this invention. It is a figure which shows the relationship between the crank angle in connection with the internal combustion engine of a prior art, and intake pressure (air compressor action | operation). It is a figure which shows the relationship between the crank angle and intake pressure (intake valve action | operation + air compressor action | operation) in connection with the internal combustion engine of a prior art.

Explanation of symbols

1 Internal combustion engine
2 Intake pipe (intake passage)
3 Exhaust pipe (exhaust passage)
4 Air Cleaner 5 Air Compressor 6 Air Compressor Suction Pipe 6a Air Intake 7 Air Compressor Discharge Pipe 8 Intake Manifold

Claims (2)

  In an internal combustion engine provided with an air compressor, an air intake port of the air compressor is provided between an air cleaner of an intake pipe of the internal combustion engine and an intake manifold, and a pressure wave of intake pulsation generated by the air compressor has a predetermined frequency. And driving the air compressor so as to have an opposite phase at the same frequency as the pressure wave of the intake pulsation of the internal combustion engine.   2. The internal combustion engine according to claim 1, wherein the air compressor is driven by a crankshaft of the internal combustion engine.

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