JPS6141949Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a secondary air supply device for an engine.

Conventionally, the secondary air supply device for an engine is
As in the device shown in FIG. 1 disclosed in Japanese Utility Model Application No. 52-132912, the secondary air conduits 3, 3 downstream of the secondary air filter 2 of the air cleaner 1 are made independent for each cylinder 4, 4. Proposed.

However, the conduit inlets 6, 6 on the side of the reed valves 5, 5
are arranged close to each other on the inner wall of the air cleaner 1, so intake interference of secondary air occurs,
The amount of intake air sometimes decreased.

Furthermore, since the secondary air passes through the dirty side of the air cleaner 1 during intake, intake noise may also be generated.

This idea was made in view of the above-mentioned conventional problems. Two systems of secondary air conduits are formed along the inner wall of the case on both sides of the air cleaner element, and each passage is independently connected to the expansion chamber. This expansion chamber is configured to communicate with the exhaust system through two systems of secondary air conduits via independent filters and reed valves, and the separation of the air intake ports of the secondary air passages prevents intake interference and improves the intake. In addition to increasing the amount of air,
This system is designed to prevent intake noise from occurring through the silencing effect of the secondary air passage.

Hereinafter, embodiments of this invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the air cleaner 11 includes a case 15 in which a disc-shaped cover 12 is closed to a circumferential wall 14 of a main body 13, and a cylindrical element 16 is installed concentrically within the case 15. On the other hand, an outside air intake port 17 is provided on the upper side of the circumferential wall 14 in the figure, and the main body 1
An intake port 20 communicating with an intake passage 19 of an engine 18 is provided on the center side of the engine 3 .

On the lower side in the figure of the circumferential wall 14 of the case 15,
Independent expansion chambers 22a, 22 separated by a partition plate 21
b, and a filter 2 is provided in each expansion chamber 22a, 22b.
3a, 23b and reed valves 24a, 24b are provided, respectively, and each expansion chamber 22a, 22b is connected to the exhaust pipe 26 of the engine 18 via two systems of secondary air conduits 25a, 25b, respectively.

Two systems of secondary air passages 27a and 27b are formed along the circumferential wall 14 of the case 15.

One of the secondary air passages 27a is a long passage with a square cross section, as shown in FIG. , the suction port 29a is opened near the outside air intake port 20, and the suction port 29a is opened near the outside air intake port 20.
9b is connected to one of the expansion chambers 22a.

As shown in FIG. 3b, the other secondary air passage 27b is a long passage with a circular cross section formed by welding a pipe material 30 to the corner of the bottom of the main body 13 and the circumferential wall 14. The suction port 29a of one of the secondary air passages 27a is set at a substantially symmetrical position with respect to the center of the element 16, and the suction port 3
1b is connected to the other expansion chamber 22b.

Therefore, the suction port 2 of one secondary air passage 27a
9a and the suction port 31a of the other secondary air passage 27b
This means that they are separated from each other without facing or being close to each other.

On the lower left side in the figure of the circumferential wall 14 of the case 15, there is a valve plate 32 that closes the middle of the one secondary air passage 27a, and a negative pressure chamber 3 facing the valve plate 32.
The diaphragm 34 is provided with a diaphragm 34 forming a valve 3, and the diaphragm 34 is provided with a valve body 37 which is biased in the valve opening direction by a coil spring 35 and can freely open and close the valve holes 36, 36 of the valve plate 32. Leakage hole 41 of valve plate 32
is always open regardless of whether the valve body 37 is opened or closed.

The negative pressure chamber 33 communicates with a negative pressure port 39 of the intake passage 19 immediately upstream of the throttle valve 38 via a negative pressure passage 40 .

If the secondary air supply device is configured as described above,
When exhaust gas flows through the exhaust pipe 26 due to the operation of the engine 18, the reed valves 24a and 24
b opens and closes, and the air introduced into the case 15 from the outside air inlet 17 flows through each secondary air passage 27a, 2
7b to each expansion chamber 22a, 22b, and each secondary air conduit 2 passes through a filter 23a, 23b.
It comes to be supplied to the exhaust pipe 26 from 5a and 25b.

When the engine 18 is idling, decelerating, or operating under high load with the throttle valve 38 fully open, the valve element 37 is open because the negative pressure in the negative pressure chamber 33 is small in one secondary air passage 27a. , each hole 36, 41 of the valve plate 32 and the drain hole 4
During other operations, the negative pressure in the negative pressure chamber 33 becomes high and the valve body 37 closes, and the secondary air is introduced only from the leak hole 41 of the valve plate 32. Since no air is introduced, the consumption of secondary air is reduced.

Inlet port 2 of each of the secondary air passages 27a, 27b
Since the elements 9a and 31a are separated by sandwiching the element 16, interference with the intake air of secondary air is prevented, and the amount of intake air is increased.
Since the secondary air passages 27a and 27b have a long passage length, they have a noise-muffling effect, and the generation of intake noise is also prevented.

As described above, this invention has two systems installed along the inner wall of the case on both sides of the air cleaner element.
A secondary air passage is formed, and each passage is independently connected to the exhaust system via an expansion chamber, a filter, a reed valve, and a secondary air conduit.

Therefore, since the inlets of each secondary air passage are separated from each other, intake air interference is prevented and the amount of intake air can be increased, and the generation of intake noise can also be prevented by the silencing effect of each secondary air passage.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional secondary air supply device, Fig. 2 is a sectional view of a secondary air supply device according to this invention, Fig. 3a is a sectional view taken along line A-A in Fig. 2, and Fig. 3 b
is a sectional view taken along line B-B in FIG. 2; 11... Air cleaner, 14... Circumferential wall, 15
... Case, 16 ... Element, 17 ... Outside air intake, 18 ... Engine, 19 ... Intake passage,
20...Intake intake port, 22a, 22b...Expansion chamber, 23a, 23b...Filter, 24a, 24
b...Reed valve, 25a, 25b...Secondary air conduit, 26...Exhaust pipe, 27a, 27b...Secondary air passage, 29a, 31a...Intake port, 29b, 3
1b... Suction port.

Claims (1)

[Scope of utility model registration request] Two systems of secondary air passages are formed along the inner wall of the air cleaner case on both sides of the air cleaner element, and the outlets of each of the secondary air passages are opened in expansion chambers formed independently, and the expansion chamber and the exhaust A secondary air supply device for an engine, characterized in that a filter and a reed valve are provided in two systems of secondary air conduits that are independently connected to the system.