JPH0139894Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) This invention is a mounting structure for an intake system heat shield, specifically, it is attached to a plastic intake pipe, and the intake air is interposed between the intake pipe and the high temperature part of the engine. The present invention relates to the mounting structure of a system heat shield plate.

(Prior Art) As a conventional intake system for an internal combustion engine, the one shown in Fig. 1 is known, for example (Toyota Motor Corporation, September 22, 1980, "Toyota Corona Handbook", p. 59) ,reference). To briefly describe this device, in FIG. 1, reference numeral 1 denotes an intake pipe for introducing intake air into a turbocharger 2, one end of which is connected to an air cleaner 3, and the other end connected to a compressor housing of the turbocharger 2.
Moreover, this intake pipe 1 has a rubber hose 1A at one end.
, a rubber hose 1B on the other end side, and a steel air tube 1C that connects these rubber hoses 1A and 1B. 4 transfers the intake air compressed by the turbocharger 2 to the intake manifold 5
One end is connected to the compressor housing of the turbocharger 2, and the other end is connected to the collecting pipe 6 of the intake manifold 5. Moreover, a rubber hose 4A is formed in the middle of this intake pipe 4, and steel air tubes 4B and 4C are connected to both ends thereof, respectively. Further, the collecting pipe 6 branches into a plurality of branch pipes 7, and these branch pipes 7 are respectively connected to respective intake ports communicating with the combustion chamber. Note that 8 is an exhaust pipe, and the exhaust gas in the exhaust pipe 8 drives the turbocharger 2 to rotate.

Therefore, this intake device has intake pipes 1 and 4 disposed near the turbocharger 2 and the exhaust pipe 8.
By making the air tubes 1C, 4B, and 4C (more specifically, the air tubes 1C, 4B, and 4C) made of steel, the intake pipes 1 and 4 are prevented from being damaged by heat transmitted from the exhaust pipe 8 and the like.

However, such conventional intake systems for internal combustion engines use intake pipes made of steel pipes, which has the problem of increasing their weight and increasing the weight of the entire system. . Another problem is that when the intake pipe is bent, springback occurs, making connection and assembly difficult. Therefore, it may be possible to use a plastic intake pipe to reduce weight and improve assembly work, but in this case, a heat shield plate is required to prevent deformation and damage due to radiant heat from the high temperature parts of the engine. Moreover, since it is made of plastic, its rigidity is lower than that of a steel pipe, which causes membrane vibration and increases noise.

(Purpose of the invention) Therefore, when installing a heat shield plate in the vicinity of the engine's high-temperature part of the intake pipe, the present invention has been developed by tightening a band-shaped elastic body at a predetermined position in the length direction of the plate over the entire circumference.
By supporting the heat shield plate through this elastic body, the purpose is to prevent thermal damage and reduce membrane vibration.

(Structure of the invention) The installation structure of the intake system heat shield plate according to this invention is a mounting structure of the intake system heat shield plate that is attached to a plastic intake pipe and interposed between the intake pipe and the high temperature part of the engine. In the structure, a band-shaped elastic body is fitted over the entire circumference at a predetermined position in the length direction of the intake pipe, and a heat shield plate is provided to surround more than half of the outer circumference of the intake pipe through a gap with the intake pipe. In this structure, a belt-shaped holding member for holding the intake system heat shield plate is provided, and the holding member is tightly supported by the intake pipe via the elastic body.

(Example) Hereinafter, an example of this invention will be described based on the drawings.

2 to 4 show an embodiment of this invention.

First, to explain the configuration, in Figure 2, 1
Reference numeral 1 indicates an intake manifold (branch pipe) fixed to the cylinder head 13 of the engine body 12, and reference numeral 14 indicates a collecting pipe connected to the intake manifold 11. Throttle body 1 is installed in collecting pipe 14.
5 are connected to each other, and a throttle valve 16 is disposed within the throttle chamber. This throttle valve 1
Reference numeral 6 controls the amount of intake air in conjunction with an accelerator pedal (not shown). 17 is air cleaner 18
This is an intake pipe that supplies air to the intake manifold 11 after detecting the air taken in through the air flow meter 19 with an air flow meter 19. One end of the intake pipe is connected to the throttle body 15, and the other end is connected to the air cleaner 18. This intake pipe 17 is molded from plastic, and is connected with a rubber hose 20 midway. On the other hand, 21 is the exhaust pipe 2
This is an EGR recirculation pipe that recirculates a part of the exhaust gas in the intake manifold 11 to the intake manifold 11.
An EGR control valve 23 is provided at the connection part with 1. The EGR control valve 23 controls the EGR amount based on the suction negative pressure introduced through the negative pressure pipe 24 opening to the throttle body 15. Also, 2
Reference numeral 5 denotes a blow-by gas recirculation pipe, and this blow-by gas recirculation pipe 25 removes the oil contained in the blow-by gas leaked into the crankcase 26 in an oil separation chamber 27, and then returns the blow-by gas to the collecting pipe 14 via the PCV valve 28. Bring it back inside. Note that 29 is an injector that injects fuel into the combustion chamber 30.

Here, disposed near the exhaust pipe 22 etc.,
A heat shield plate 31 is installed on the outer wall of the intake pipe 17, which is easily heated.
is installed. FIG. 3 is an enlarged sectional view of a main part showing the attached state, and FIG. 4 is a view taken along the - arrow in FIG. 3. In these figures, 32
is a band-shaped elastic body made of, for example, rubber, and the elastic body 32 is attached to a predetermined position in the length direction of the intake pipe 17 by being crimped over its entire circumference. That is, two band-shaped elastic bodies 32 are fitted to the outer wall of the intake pipe 17 at predetermined positions in the length direction, and the interval between these elastic bodies 32 is set to a predetermined length l. Further, a band-shaped holding member 33 having the same width is closely attached to the outer peripheral surface of these elastic bodies 32, and both ends thereof are tightened with bolts 34. Therefore, a predetermined position in the length direction of the intake pipe 17 is tightened by the elastic body 32 and the holding member 33. The heat shield plate 31 is formed of a curved soft iron plate, and prevents the plastic intake pipe 17 from being damaged by heat by blocking high heat released from high temperature parts of the engine such as the exhaust pipe 22. The heat shield plate 31 has a length of about 30 cm in the axial direction of the intake pipe 17, and is formed in an arcuate shape so as to cover more than half (about 2/3) of the outer circumference of the intake pipe 17. The heat shield plate 31 is attached to the holding member 3 via a plurality of mounting stays 35 provided along the circumferential direction.
3, this heat shield plate 31 and the intake pipe 1
7, there is a predetermined gap 36 that blocks heat transfer.
is formed. That is, the holding member 33 is tightly supported by the intake pipe 17 via the elastic body 32. The mounting stay 35 has a substantially inverted trapezoidal cross section, and both upper ends in FIG.
are fixed to each.

Next, the effect will be explained.

In the intake system heat shield mounting structure of the above structure, since the intake pipe 17 is molded from plastic, its weight can be reduced, so that the overall weight of the device can be reduced. Further, since the dimensional accuracy of the intake pipe 17 can be improved, its assembly and connection become easier.

However, since the intake pipe 17 is made of plastic, the intake pipe 17 is heated by heat from the high-temperature parts of the engine, causing damage to the intake pipe 17, or being excited by intake pulsation, causing membrane vibration. For this reason, on the one hand, this embodiment prevents the intake pipe 17 from being damaged by heat by supporting the heat shield plate 31 on the intake pipe 17 via the elastic body 32. That is, heat from high-temperature parts of the engine such as the exhaust pipe 22 is first blocked by the heat shield plate 31, and then heat transferred from the heat shield plate 31 to the holding member 33 via the mounting stay 35 is blocked by the surface of the mounting stay 35. At the same time, the air is discharged from the air into the air gap 36, and due to the heat insulating action of the elastic body 32, the intake pipe 17
Prevents heat conduction to. Therefore, the durability of the plastic intake pipe 17 will not deteriorate due to heat.

On the other hand, by tightening the band-shaped elastic body 32 at a predetermined position in the length direction of the intake pipe 17 over the entire circumference, the elastic body 32 absorbs the vibration energy of the natural vibration of the intake pipe 17 caused by the intake pulsation of the intake system. It is reduced by the action. In other words, the frequency of the intake sound generated by the natural vibration of the intake pipe 17 is 250.
It is known that it is most noticeable in the region of ~500 Hz (the wavelength λ is 1.36 to 0.68 m when the sound speed is 340 m/sec). Therefore, the tightening position of the elastic body 32 with respect to the intake pipe 17 is set to match the abdomen where the amplitude of the natural vibration is maximum, and the elastic body 32 is set at an interval corresponding to, for example, 1/4 wavelength λ (0.34 to 0.17 m). By disposing a plurality of elastic bodies 32 (L = 0.34 to 0.17 m above), the natural vibration (membrane vibration) of the intake pipe 17 can be effectively damped, and as a result, the generation of intake noise can also be prevented. . Further, as the membrane vibration of the intake pipe 17 is reduced, the vibration of the heat shield plate 31 can also be reduced, and since the elastic body 32 has a large coefficient of friction, the heat shield plate 31 held through the elastic body 32 can be Rotation on the intake pipe 17 due to vibration can be reliably prevented.

(Effects) As explained above, according to this invention,
Since the weight of the intake pipe can be reduced, the weight of the entire device can be reduced, and dimensional accuracy can be improved, so assembly and connection can be facilitated. Further, since both heat conduction to the intake pipe and its natural vibration can be reduced, deterioration in the durability of the intake pipe can be prevented, and generation of intake noise can also be prevented.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram showing a conventional intake system device.
Figures 2 to 4 show an embodiment of the mounting structure for the intake system heat shield according to this invention, with Figure 2 being an overall configuration diagram, and Figure 3 being an enlarged cross-section of the main parts of Figure 2. figure,
FIG. 4 is a view taken along the - arrow in FIG. 17...Intake pipe, 31...Heat shield plate, 32...Elastic body, 33...Holding member, 36...Gap.

Claims (1)

[Scope of utility model registration request] A mounting structure for an intake system heat shield that is attached to a plastic intake pipe and is interposed between the intake pipe and the high temperature part of the engine, the heat shield plate having a heat shield plate that extends all around the intake pipe at a predetermined position in the length direction of the intake pipe. While the band-shaped elastic body is fitted, a heat shield plate is formed to surround more than half of the outer circumference of the intake pipe through a gap with the intake pipe, and
A mounting structure for an intake system heat shield plate, characterized in that a band-shaped holding member for holding the intake system heat shield plate is provided, and the holding member is tightly supported on the intake pipe via the elastic body.