JPS6113732Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an exhaust recirculation control device for an internal combustion engine.
In particular, it relates to a means for opening each negative pressure signal passage to the atmosphere, which sends a negative pressure signal to two exhaust gas recirculation control valves that are provided in parallel in the exhaust gas recirculation passage and each operated by a different negative pressure signal (see JP-A-53-143824). ).

As an example of an exhaust gas recirculation control device prior to the present application, there is one shown in FIG. 1, for example. That is, two negative pressure responsive exhaust recirculation control valves 4 and 41 are provided in parallel in the exhaust recirculation passage 2 connected to the intake passage 1, and a first negative pressure that guides a negative pressure signal to one exhaust recirculation control valve 4 is provided. The opening rate of the signal passage 8 to the atmosphere is changed by the negative pressure control valve 9, and the second negative pressure signal passage 32 which guides the negative pressure signal to the other exhaust gas recirculation control valve 41 is replaced by the third negative pressure signal passage 32.
The first negative pressure signal path 8 and the third negative pressure signal path 2
1 and 1 are opened to the atmosphere through temperature-responsive on-off valves 91 and 92 that open and close depending on the temperature of the cooling water 46, respectively, and the exhaust recirculation control valves 4 and 41 have different operating characteristics, Appropriate exhaust gas recirculation characteristics can be obtained depending on the operating condition of the engine.

However, such conventional exhaust recirculation control devices are configured to use two water temperature-responsive on-off valves that open and close depending on the cooling water temperature, and these water temperature-responsive on-off valves are not used in the engine. There were problems in that two installation spaces were required, and the piping was complicated, which was disadvantageous in terms of maintenance and inspection, cost, etc.

The present invention was developed by focusing on these conventional problems, and uses a water temperature-responsive on-off valve that opens and closes depending on the cooling water temperature only in the first negative pressure signal path. The above problem can be solved by communicating the pressure signal passage and the third negative pressure signal passage through a check valve that allows atmospheric air to flow only toward the third negative pressure signal passage. The purpose is

Hereinafter, the present invention will be explained in detail based on an embodiment shown in FIG.

In the figure, an exhaust gas recirculation passage 2 branched from an exhaust passage (not shown) is connected to an intake passage 1 downstream of a carburetor throttle valve 6 of an internal combustion engine mounted on a vehicle. A valve body 3 provided in the exhaust gas recirculation passage 2 is connected to a diaphragm 5 of a negative pressure responsive exhaust recirculation control valve 4, and a negative pressure operating chamber 7 defined by the diaphragm 5 and a throttle valve 6 are fully closed. In the condition, the throttle valve 6
It is connected via a first negative pressure signal passage 8 to a first negative pressure take-out port 8a that opens into the intake passage 1 on the slightly upstream side. The negative pressure signal of the first negative pressure signal passage 8 is adjusted to be diluted with the atmosphere by the valve body 9a of the negative pressure control valve 9. That is, the negative pressure control valve 9 connects the vent lily negative pressure signal passage 10 from the vent lily portion 1a of the intake passage 1 to the negative pressure working chamber 11, and connects the upstream portion 4a of the exhaust recirculation control valve 4 of the exhaust gas recirculation passage 2 to the negative pressure working chamber 11.
An exhaust pressure signal passage 13 branched from the negative pressure control valve 9 is connected to a pressure working chamber 14 of the negative pressure control valve 9, and diaphragms 12 and 15 defining these working chambers 11 and 14 are interconnected via a rod 16. ing. The valve body 9a is then moved up and down by moving the diaphragms 12 and 15 up and down based on the vent lily negative pressure in the intake passage 1 (a function of the amount of intake air) and the exhaust pressure in the exhaust gas recirculation passage 2 (a function of the amount of intake air, load, etc.). is moved, the atmosphere opening passage 8b to the first negative pressure signal passage 8 is opened and closed, and as the amount of intake air calculated from the bench lily negative pressure increases,
As the amount of intake air converted from the exhaust pressure and the load increase, the atmospheric dilution ratio of the first negative pressure signal passage 8 (the atmospheric dilution ratio of the intake negative pressure) is decreased,
The opening degree of the valve body 3 of the exhaust gas recirculation control valve 4 is increased to increase the amount of exhaust gas recirculation. Although the negative pressure control valve 9 is designed to operate based on the exhaust pressure passing through the exhaust pressure signal passage 13 and the ventilator negative pressure passing through the ventilator negative pressure signal passage 10, it may be structured to respond to at least the exhaust pressure.

On the other hand, a valve body 40 provided in the exhaust gas recirculation passage 2 in parallel with the valve body 3 is connected to a diaphragm 42 of a negative pressure-responsive exhaust gas recirculation control valve 41. The chamber 43 is connected to the second negative pressure signal passage 32 via a negative pressure control valve 33 in the middle.
It is connected to a second suction negative pressure extraction port 32a that opens into the intake passage 1. Further, a third negative pressure signal passage 2 is connected to a third negative pressure output port 19 that opens into the intake passage 1 slightly upstream of the first negative pressure output port 8a.
1 and the passage 21 is connected to the negative pressure working chamber 34 of the negative pressure control valve 33. This negative pressure control valve 33
The negative pressure enters the negative pressure working chamber 34 from the third negative pressure output port 19 through the third negative pressure signal path 21, and the negative pressure enters the negative pressure working chamber 34 from the third negative pressure signal path 21 to the delay valve 36 and the negative pressure tank. 35 and enters the negative pressure operating chamber 37, the second negative pressure signal passage 32 is opened and closed. In other words, the second negative pressure signal path 3
Open 2. Here, the first negative pressure signal path 8 and the third
The negative pressure signal passage 21 is communicated with the negative pressure signal passage 21 by a passage 21a having a check valve 25 that allows atmospheric air to flow only from the first negative pressure signal passage 8 toward the third negative pressure signal passage 21. Further, the first negative pressure signal passage 8 includes a passage 8c and a passage 2 having a water temperature-responsive on-off valve 44 for introducing the cooling water 46 into the atmosphere at a predetermined temperature or lower.
It is open to the atmosphere via 1a. Therefore, when the check valve 25 is in communication, the third negative pressure signal passage 21 is also opened to the atmosphere via the water temperature responsive on-off valve 44.

Specifically, the check valve 25 is designed as shown in FIG. The communication hole 25b of the partition wall 25a that partitions the A and B chambers is closed by a valve body 25d by the spring force of a spring 25c located in the B chamber near the third negative pressure signal passage 21. The valve body 25d opens only when there is a pressure difference between the A and B chambers and the pressure in the B chamber becomes low, causing an air flow from the A chamber to the B chamber.

Specifically, the water temperature responsive on-off valve 44 is as shown in FIG. A wax volume 44d having a wax 44c whose volume easily changes depending on the temperature is installed so as to be in contact with the cooling water 46 of the engine, and one end of the valve body 44a is in contact with the valve seat 44e and the other end is in contact with the inside of the wax 44c. . A spring 44b is provided on the valve body 44a so that a force in the valve opening direction is always applied to the valve body 44a.
reaches a predetermined temperature or higher, the valve body 44a closes to the valve seat 4
4e, the atmospheric passage 45 and the first negative pressure passage 8
It has been adjusted to block the

Therefore, when the temperature of the engine cooling water 46 is below a predetermined temperature, the valve body 44a is separated from the valve seat 44e, and the first negative pressure signal passage 8 is connected to the passage 21a and the passage 8.
c. The signal negative pressure that is opened to the atmosphere via the atmospheric passage 45 and supplied to the negative pressure control valve 9 is diluted with the atmosphere.
At this time, in the check valve 25, chamber A becomes atmospheric pressure, and a pressure difference is generated between chamber A and chamber B, which has a large negative pressure, and the valve body 25
Open d. As a result, the atmosphere flows into the third negative pressure signal path 21 from the atmosphere path 45 and the path 8c through the path 21a having the check valve 25, and the signal negative pressure in the third negative pressure signal path 21 is also changed to the atmosphere. It is intended to be diluted with

In addition, in such a configuration, the engine cooling water 46
When the engine is operating at a temperature equal to or higher than a predetermined temperature, the valve body 44a seats on the valve seat 44e and blocks the passage 8c from the atmosphere passage 45. Therefore, the atmosphere is not introduced into the first negative pressure signal passage 8, and the negative pressure taken out from the first negative pressure outlet port 8a is supplied as is to the negative pressure operating chamber 11 of the negative pressure control valve 9. , the atmosphere opening port of the first negative pressure signal passage 8 in response to the bench lily negative pressure led out from the bench lily portion and passed through the bench lily negative pressure signal passage 10 and the exhaust pressure passed through the exhaust pressure signal passage 13 taken out from the exhaust gas recirculation passage 2. The negative pressure control valve 9 is controlled to open and close, thereby supplying a signal negative pressure diluted with atmospheric air to the exhaust recirculation control valve 4 according to the intake air amount and load, and adjusting the opening degree of the valve body 3. A predetermined amount (rate) of exhaust gas is recirculated into the intake air. On the other hand, the negative pressure taken out from the third negative pressure take-out port 19 remains as it is and is transferred to the third negative pressure signal path 2.
1 to the negative pressure operating chamber 34 of the negative pressure control valve 33 to operate the negative pressure control valve 33 normally, and when the negative pressure control valve 33 is opened, the second negative pressure signal passage 32 is opened. Then, the suction negative pressure taken out from the suction negative pressure take-out port 32a opened to the suction passage 1 is guided from the second negative pressure signal passage 32 to the negative pressure operation chamber 43 of the auxiliary negative pressure operation type exhaust recirculation valve 41, Thereby, the valve body 40 connected to the diaphragm 42
is operated in the valve-opening direction to recirculate a predetermined amount of exhaust gas into the intake air.

As explained above, according to the present invention, while maintaining the independence of the negative pressure signals to the two exhaust gas recirculation control valves, the communication between the negative pressure signal passages and the atmosphere is controlled by one water temperature responsive on-off valve. Since the engine can be controlled by the engine, the structure can be simplified, which is extremely advantageous in terms of engine layout, maintenance and inspection, and cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional exhaust gas recirculation control device, FIG. 2 is a sectional view showing an exhaust gas recirculation control device according to an embodiment of the present invention, and FIG. 3 is a detailed sectional view of section A in FIG. FIG. 4 is a detailed sectional view of section B in FIG. 2. 1...Intake passage, 2...Exhaust recirculation passage, 4...
Exhaust recirculation control valve, 8...first negative pressure signal passage, 9
... Negative pressure control valve, 21 ... Third negative pressure signal passage,
25...Check valve, 32...Second negative pressure signal passage,
33... Negative pressure control valve, 41... Exhaust recirculation control valve,
44...Water temperature responsive on-off valve, 45...Atmospheric passage,
46...Cooling water.

Claims (1)

[Scope of utility model registration request] Two negative pressure-responsive exhaust recirculation control valves are provided in parallel in the exhaust gas recirculation passage, and one of the exhaust recirculation control valves and a first negative pressure take-out port that opens into the intake passage are connected by a first negative pressure signal passage. A negative pressure control valve connected to the valve and responsive to at least the exhaust pressure changes the atmospheric dilution ratio with respect to the negative pressure in the first negative pressure signal path, and controls one exhaust gas recirculation with the negative pressure adjusted by the negative pressure control valve. While operating the control valve, the other exhaust recirculation control valve and the second negative pressure take-out port that opens into the intake passage are connected through the second negative pressure signal path, and the third negative pressure signal path is connected to opening and closing the second negative pressure signal passage using a negative pressure control valve that responds to the differential pressure between the negative pressure generated and the negative pressure introduced via the delay valve;
The exhaust recirculation control device has a structure in which the other exhaust recirculation control valve is operated only in the early stages of acceleration when a pressure difference is generated, and the exhaust recirculation control valve is provided with temperature detection means for engine cooling water and opens the valve when the cooling water is at a predetermined temperature or lower. A water temperature-responsive on-off valve for introducing atmospheric air is provided in the middle of the first negative pressure signal path, and the first negative pressure signal path and the third negative pressure signal path are connected to a third negative pressure signal path. 1. An exhaust gas recirculation control device, characterized in that the exhaust gas recirculation control device is connected through a passage having a check valve that allows atmospheric air to flow only toward the direction of the air.