JPS59119054A - Egr controller - Google Patents

Abstract

PURPOSE:To restrict an increase in intake resistance or exhaust resistance when the engine is rotated at a high speed, and accelerate an increase in EGR when the engine is rotated at a low speed. CONSTITUTION:The EGR controller 14 is comprised of an ON-OFF valve 16 for opening and closing an inflow port 10 and a throttle valve 18 for opening and closing an exhaust passage 6, which valve 16 is fixed to a valve shaft 20 fitted perpendicularly to the longitudinal direction of the exhaust passage 6, and controls the degree of opening of the inflow port 10. The throttle valve 18 is rotated with the valve shaft 20 as a center to control the degree of opening of the exhaust passage 6. When recirculation of an exhaust gas is required, the valve 16 is rotated to adjust the degree of opening. At this time, since the throttle valve 18 is in parallel with the longitudinal direction of the exhaust passage 6 and is not inclined, the exhaust resistance in the exhaust passage 6 is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an EGR control device for an exhaust gas recirculation (hereinafter referred to as rEGRJ) system that recirculates a portion of exhaust gas to the intake system. The present invention relates to an EGR control device that can suppress EGR.

EGR system is a means to reduce NOx in exhaust gas.
This system reduces the production of NOx by recirculating a portion of the inert exhaust gas to the intake system and mixing it with the intake air-fuel mixture. Some of these systems communicate the intake passage and exhaust passage through a bypass passage, and a control device is provided at the opening of the bypass passage in the intake passage or exhaust passage, thereby controlling the amount of exhaust gas circulation. .

However, in the conventional control device described above, the intake restriction in the intake passage or the exhaust restriction in the exhaust passage and the opening degree of the bypass passage are integrally controlled by a single device, so the intake resistance in the intake passage or There is a large increase in exhaust resistance in the exhaust passage, and in particular, the rate of increase in these resistances increases significantly as the engine speed increases, which is disadvantageous in that it causes a reduction in output.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the above-mentioned disadvantages, minimize the increase in intake resistance or exhaust resistance at high engine speeds, minimize the decrease in engine output, and at the same time, suppress the increase in intake resistance or exhaust resistance at high engine speeds. The object of the present invention is to realize an EGR control device that can sometimes easily promote an increase in the amount of exhaust gas circulation.

In order to achieve this object, the present invention provides an on-off valve at any opening of a bypass passage that communicates an intake passage and an exhaust passage, and a throttle that opens and closes the intake or exhaust passage in proximity to the on-off valve. The present invention is characterized in that a valve is provided, and the on-off valve and the throttle valve are configured to be interlocked when the on-off valve is opened to a predetermined degree.

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

1 to 3 show a first embodiment of the present invention, in which 2 is an internal combustion engine, 4 is an intake passage, 6 is an exhaust passage, 8 is a recirculation port formed in the intake passage 4, and 1o is a reflux port formed in the exhaust passage 6. This is the formed inlet. A bypass passage 12 is opened to communicate the recirculation port 8 and the inflow port 10, and a part of the exhaust gas is circulated into the intake passage 4 through this bypass passage 12G. 14 is an EGR control device provided at the inlet 10 position in the exhaust passage 6, and this EGR control device 14 includes an on-off valve 1 that opens and closes the inlet 1o.
6 and a throttle valve 18 that opens and closes the exhaust passage 6. The on-off valve 16 is fixed to a valve shaft 2o installed perpendicularly to the longitudinal direction of the exhaust passage 6, and rotates about the valve shaft 2o in a direction to open and close the opening of the inlet 10. The degree of opening of the inlet 10 is controlled. On the other hand, the throttle valve 18 has its center fitted loosely to the valve shaft 20, and rotates around the valve shaft 20 to adjust the opening degree of the exhaust passage 6 by adjusting the inclination with respect to the longitudinal direction of the exhaust passage 6. It's in control. Reference numeral 22 designates a protruding piece protruding from the on-off valve 16, and this protruding piece 22 is provided so as to come into contact with the throttle valve 18 when the on-off valve 16 is fully opened. Then, when the on-off valve 16 further rotates in the same direction as the fully open direction, this protrusion piece 22
has the function of pressing the throttle valve 18, rotating the throttle valve 18, and inclining the throttle valve 18 with respect to the longitudinal direction of the exhaust passage 6 to close the exhaust passage 6. Note that the protruding piece 22
may be provided protrudingly at a position where the on-off valve 16 abuts against the throttle valve 18 at a predetermined opening state before being fully opened.

4 to 6 show a second embodiment of the present invention, in which an EGR control device 14 is provided at a recirculation port 8 in the intake passage 4. In FIG. The configuration other than this is the same as the first embodiment.

Since this invention is constructed as described above, the exhaust passage 6
When the EGR control device 14 is provided in the engine, the operation is as follows.

When exhaust circulation is not necessary, use an on-off valve! 6 to close the inlet 10 (FIG. 7(A)).

When circulation of exhaust gas is required, the opening/closing valve 16 is rotated in the direction of arrow X to adjust the opening degree and control the amount of exhaust gas circulation.

As a result, a portion of the exhaust gas flows into the inlet 10 and is circulated into the intake passage 4 via the bypass passage 12. At this time,
Since the throttle valve 18 is parallel to the longitudinal direction of the exhaust passage 6 and is not inclined, the exhaust resistance in the exhaust passage 6 is minimized (7th
Figure (B)).

When sufficient exhaust circulation cannot be achieved by adjusting the on-off valve 16 alone, or when the exhaust resistance in the exhaust passage 6 is not a big problem, the on-off valve 16 that is fully open is further turned in the same direction as the fully open direction (arrow X direction). When the throttle valve 18 is rotated, the protruding piece 22 protruding from the fully opened on-off valve 16 presses and rotates the throttle valve 18. As a result, the throttle valve 18 is inclined with respect to the longitudinal direction of the exhaust passage 6 and narrows the degree of opening of the exhaust passage 6, increasing the exhaust pressure and increasing the pressure difference with the intake passage 4. , the exhaust goes to the lower pressure intake passage 4 side,
A suction force is generated through the bypass passage 12, making it possible to circulate a large amount of exhaust gas toward the intake passage 4 (
Figure 7(C)).

On the other hand, even when the EGR control device 14 is provided in the intake passage 4, control can be performed in the same manner as described above (see Fig. 8 (A).
) (B) (C)). In addition, in the case of FIG. 8(C), the negative pressure near the inlet 10 is large (as a result, the pressure difference with the inside of the exhaust passage 6 becomes large).

Furthermore, by protruding the protruding piece 22 at a position where the on-off valve 16 contacts the throttle valve 18 at a predetermined opening state before it is fully opened,
It becomes possible to realize a desired EGR flow rate and control mode.

As is clear from the above detailed description, according to the configuration of the present invention, the throttle valve that opens and closes the intake passage or the exhaust passage is in a fully open state or a predetermined opening state. Since it functions in unison with the intake and exhaust resistance, at high engine speeds when it is necessary to suppress intake and exhaust resistance as much as possible, the circulation amount of exhaust gas can be controlled by adjusting the opening/closing valve that does not create these resistances. Since the throttle valve that creates intake resistance or exhaust resistance only functions when the opening/closing valve alone is insufficient, the intake resistance or exhaust resistance in each passage can be suppressed as much as possible, minimizing the drop in engine output. It can be suppressed. Moreover, at low engine speeds, where intake resistance or exhaust resistance in each passage is not a problem at high speeds, by adjusting the throttle valve 1, a pressure difference is created between the intake and exhaust passages. By using this pressure difference, it is possible to easily promote an increase in the amount of exhaust gas circulation and to perform accurate control.

[Brief explanation of the drawing]

The drawings show an embodiment of the EGR control device according to the present invention,
1 to 3 show a first embodiment of the present invention. FIG. 1 is a schematic system diagram, FIG. It is a sectional view taken along mm. 4 to 6 show a second embodiment of the present invention, in which FIG. 4 is a schematic system diagram, FIG. V
It is a 1-Vl sectional view. 7(A), 7(B), and 7(C) are explanatory views of the operation of the first embodiment, and FIGS. 8(A), 8(B), and (C) are explanatory views of the operation of the second embodiment. In the figure, 2 is an internal combustion engine, 4 is an intake passage, 6 is an exhaust passage, and 8
10 is a recirculation port, 10 is an inlet, 12 is a bypass passage, 14 is an EGR control device, 16 is an on-off valve, 18 is a throttle valve, 20 is a valve shaft, and 22 is a protruding piece. Agent Patent Attorney Yoshimi Saigo Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] An on-off valve is provided at any opening of a bypass passage that communicates the intake passage and the exhaust passage, and a throttle valve is provided adjacent to the on-off valve for opening and closing the intake or exhaust passage;
An EGR control device characterized in that the on-off valve and the throttle valve are configured to be interlocked when the on-off valve is opened to a predetermined degree.