JPS6210448Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a deceleration device for an internal combustion engine that sucks air into the intake passage downstream of the throttle valve in order to prevent the consumption of lubricating oil from increasing when the engine decelerates. be.

Figure 1 is a cross-sectional view showing the configuration of the main parts of a conventional speed reduction device.A bypass passage 1 that bypasses a throttle valve (not shown) in the intake passage has a control that opens when the engine's intake negative pressure exceeds a set value. A valve 2 is provided to suck air into the intake passage 8 downstream of the throttle valve when the engine is decelerated, thereby preventing an increase in the concentration of HC discharged (for example, Japanese Utility Model Application No. 54-61125).

However, in such a conventional speed reducer, the installation length of the return spring 4 in the control valve 2 remains unchanged, so the opening pressure of the control valve 2 varies greatly due to variations in the return spring 4. , narrow valve opening tolerance range (-570 to -600mm
Hg) was difficult to set. Further, the spring force of the return spring 4 is adjusted by rotating a threaded portion 5 formed on the outer periphery of the bypass passage 1 and screwed onto the housing 3 of the control valve 2 to displace the valve seat 6. In this case, the valve opening pressure of the valve 7 changes due to unauthorized modification of the valve seat 6 by the operator, resulting in problems such as poor operability, noise and wear accompanying the opening and closing of the valve 7.

This invention was made by focusing on the above-mentioned conventional problems, and includes forming a threaded part inside the outlet part of the control valve, and installing the spring seat member by screwing it into the threaded part.
By rotating the spring seat member relative to the outlet portion, the mounting length of the return spring can be made variable, and by configuring the passage opening area of the outlet portion to be larger than the passage opening area of the valve seat portion of the control valve. The purpose of this is to prevent variations in the opening pressure of control valves and to eliminate poor drivability caused by unauthorized modification.

This invention will be explained in detail below based on the drawings.

FIG. 2 is a sectional view of the entire structure showing an embodiment of this invention. In this figure, 11 is a throttle chamber, 12 is an intake passage, 12a and 12b are upstream and downstream of the intake passage of the intake passage 12, 13 is a throttle valve, 14 is a case screwed onto the intake passage 12, 15
1 is a bypass passage that bypasses the throttle valve 13;
Reference numeral 6 denotes a control valve section provided in the bypass passage 15, and the details of this configuration are shown in FIG. 3.

In FIG. 3a, the control valve case 14 consists of a part 14b (outlet part) that screws into the intake passage and a part 14a (inlet part) that covers the valve 20, into which a spring seat member 21 is screwed. . That is, 17 is a valve seat provided at the intake inlet and has an opening 17a;
Reference numeral 1 designates a spring seat member that is screwed onto the outlet portion 14b, and has a threaded portion 21b formed on its outer periphery, and this threaded portion 21b is screwed onto the outlet portion 14b of the case 14. Further, the threaded portion 21b has a recess 2 for rotation by an adjustment tool, as shown in FIG. 3b.
1c is formed. An opening 21e is formed in the small-diameter wall 21d of the spring seat member 21, and a stopper 18 made of rubber, resin, etc. for regulating the maximum lift of the valve 20 is inserted and fixed into the opening 21e. Further, the spring seat member 21 has an opening 21 in the peripheral part.
a is formed.

The valve 20 is formed as a plate-shaped body made of stainless steel, and as shown in FIG.
The valve 20 has a notch 20b that forms an air passage between the convex portion 20a that slides with the inner wall 14d of the hollow portion, and the return spring 22 is installed between the spring seat member 21 and the valve 20. A return spring 22 is inserted through a valve seat 17 made of an elastic sealing material such as rubber.
A predetermined tension is applied by the spring force.

After adjusting the valve opening pressure, the spring seat member 21 screwed onto the outlet portion 14b of the case 14 is inserted into the outlet portion 14b of the case 14 using the recessed portion 21c with, for example, a punch.
Rotation is prevented by deforming a part of the shaft and caulking or welding.

In short, by rotating the spring seat member 21, the installation length of the return spring 22 can be adjusted, so the valve opening pressure can be adjusted within a predetermined range, and the control valve 1
6 production yield can be improved. In addition, even if the spring seat member 21 is displaced, the thread pitch of the threaded portion 21b is made smaller than the thread pitch on the outer periphery of the case 14 (that is, the adjustment thread pitch is equal to the spring wire diameter, approximately 0.5 to 1.5 m/m), so The return spring 22 can be adjusted to prevent it from collapsing, improving accuracy, and the stopper 18 can regulate the maximum lift of the valve 20, thereby preventing runaway of an electronically controlled fuel injection engine that supplies fuel according to the amount of intake air. This can prevent problems such as problems and poor drivability.

Next, the effect will be explained.

Air taken into the engine is taken in through the air cleaner 23, the intake path upstream 12a of the throttle valve 13 of the throttle chamber 11, and the intake path downstream 12b. Now, the throttle valve 13 in the intake passage 12 that engages with the accelerator pedal (not shown) is held at the idle opening position,
When the engine speed increases, the intake path downstream 1 of the throttle valve 13
The negative pressure inside 2b increases. When the negative pressure in the downstream side 12b of the intake passage is equal to or higher than a set value, for example -570 mmHg, the valve 20 of the control valve 16 opens against the spring force of the return spring 22, and the air flow meter 19
Air is introduced into the bypass passage 15 from the intake passage upstream 12a of the control valve 16 through the intake passage downstream 12b.
control the increase in negative pressure. 15a is a rubber hose.

This intake air is drawn into the combustion chamber 26 via the intake valve 25, but because the control valve 16 prevents excessive negative pressure, the engine lubricating oil flows into the combustion chamber 26 through the gap between the outer periphery of the piston 27 and the cylinder wall 28. Prevents suction to the surface and improves lubricant consumption. valve 20
By aligning the valve opening timing (negative pressure) with the fuel cutoff timing of the injection valve 24, engine braking is performed because there is no fuel supply based on the signal of the air flow meter 19 when the control valve 16 is opened, that is, there is no output. It works well.

Further, the opening cross-sectional area of the bypass passage 15 of the throttle valve 13 is large downstream, and (opening area of the opening 17a)<
By setting (opening area of opening 21a)≦(opening area of opening 21f of outlet portion 14b), responsiveness and valve opening characteristics can be improved.

As explained above, this invention forms a threaded part inside the outlet part of the control valve, provides a spring seat member that is screwed into the threaded part, and rotates the spring seat member with respect to the outlet part. Since the installation length of the return spring between the spring seat member and the valve can be adjusted, the valve opening characteristics can be adjusted accurately within the allowable value.
It is possible to improve the effects caused by variations in return spring assembly.

Furthermore, since the adjustable spring seat member is provided inside the case of the control valve, stable characteristics can be maintained without being tampered with from the outside.

Furthermore, since the passage opening area at the control valve outlet is made larger than the passage opening area at the valve seat of the control valve, the pressure drop caused by the airflow flowing through the valve can be reduced, and the negative pressure in the downstream passage of the control valve can be reduced. The valve can be opened and closed responsively depending on the pressure, and control accuracy can be further improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the configuration of the main parts of a conventional speed reduction device, Fig. 2 is a sectional view of the entire structure showing an embodiment of this invention, and Figs. 3 a, b, and c are the control of Fig. 2. 3A is an enlarged sectional view of the control valve, FIG. 3B is an end view of FIG. 3A, and FIG. 3C is a plan view of the valve. DESCRIPTION OF SYMBOLS 11... Throttle chamber, 12... Intake path, 12a... Upstream of the intake path, 12b... Downstream of the intake path, 13... Throttle valve, 14... Case, 15... Bypass passage, 16... Control valve , 17... Valve seat, 1
8...Stopper, 20...Valve, 20a...Protrusion,
20b...Notch, 21...Spring seat member, 21a
...Opening, 22...Return spring.

Claims (1)

[Scope of utility model registration request] In a reduction gear device for an internal combustion engine, a control valve is provided in a bypass passage that bypasses a throttle valve in an intake passage, and the control valve opens when the intake negative pressure is equal to or higher than a set value. Attach the spring seat member by screwing it together, install a return spring between the spring seat member and the valve, and adjust the installation length of the return spring by rotating the spring seat member relative to the outlet section. 1. A speed reduction device for an internal combustion engine, characterized in that the passage opening area of the outlet portion is larger than the passage opening area of a valve seat portion of the control valve.