JPH0681720A - Exhaust gas recirculation device of multi-cylinder engine - Google Patents

Abstract

PURPOSE:To provide an engine with an exhaust gas recirculation(EGR) device which secures sufficiently an EGR amount in an EGR region, restrains the generation of resonance phenomenon by pulsation effect of air-intake generated caused by the presence of an EGR port when high air-intake efficiency and a large engine torque are required in driving of the engine, and prevents the air-intake efficiency from being reduced. CONSTITUTION:In an engine provided with air-intake passages 2 independent in an air-intake manifold by cylinders, a sluice valve 30 for opening and closing opening portions 24 are provided on the opening portions 24 wherein EGR passages 21, 23 communicated with the air-intake passage 2 are communicated with the air-intake passages 2, and the sluice valve 30 is constituted so as to close the opening portions 24 when a control valve 22 of an exhaust gas recirculation device is closed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of intake efficiency of a multi-cylinder engine having an exhaust gas recirculation device and an exhaust gas recirculation passage having an opening communicating with an intake passage in an intake manifold.

[0002]

2. Description of the Related Art Exhaust Gas Recirculation System (Exhaust Gas Recirc)
FIG. 5 shows a structure in the vicinity of the intake / exhaust valve of a conventional normal engine that does not include a U.S. system, and FIG. 6 shows a structure in the vicinity of the intake / exhaust valve of an engine having the EGR. . In FIG. 5, 1
Is a surge tank, 2 is an intake manifold intake passage, 3 is an intake valve, 5 is an exhaust valve, 6 is an exhaust manifold exhaust passage,
Reference numeral 8 is a piston, and 10 is an engine body. FIG. 6 shows a case where an EGR is attached to the engine. The exhaust gas (EGR gas) E taken out from the exhaust manifold internal exhaust passage 6 is an EGR first passage 21, a control valve of an exhaust gas recirculation device (hereinafter referred to as an EGR valve). 22), an EGR second passage 23, and an opening (hereinafter, referred to as an EGR port) 24 that communicates with the intake manifold intake passage 2 and enters the intake passage 2, and the intake valve 3 and the intake valve 3 inside the cylinder. Flow into.

An engine having the above EGR, and an EGR
FIG. 7 shows a diagram comparing the intake efficiency and the torque performance of a conventional normal engine that does not have. Figure 7 (a)
Shows the intake efficiency, and FIG. 7 (b) shows the state of change in torque according to each engine speed.

As shown, EGR port 2 without EGR
The engine with the EGR port 24 (line VI) has a lower intake efficiency in the region of the engine speed of medium to low speeds as compared with the normal engine without line 4 (line V), which reduces the generated torque. There is. Normally, in an engine, the intake manifold intake passage 2 is made to have a length and shape in consideration of the flow velocity, the intake pulsation effect, etc. so that the optimum intake efficiency for the engine can be obtained. On the other hand, in the engine with EGR, the EGR port 24 is arranged in the middle of the intake manifold passage 2 and the second EGR passage 2 is provided.
Intake valve 3 and EGR port 2 because they are in communication with
4 and the second EGR passage 23, an intake pulsation effect occurs and a kind of resonance phenomenon occurs. Therefore, the substantial length of the intake passage is the optimum length for improving the original designed intake efficiency. Occurs, which results in deterioration of intake efficiency.

In view of the above circumstances, in the present invention, E
When a GR engine requires high intake efficiency during operation and requires a large engine torque, the occurrence of the resonance phenomenon due to the presence of the EGR port 24 is suppressed to prevent deterioration of intake efficiency. The purpose is to provide a means for closing the EGR port in order to close it.

In the prior art, in a multi-cylinder engine, various means have been proposed as a means for appropriately and evenly distributing the EGR gas to each cylinder, for example, Japanese Patent Laid-Open No. 61-14460. Et al., The means is disclosed, but there is no proposal for a means for preventing a decrease in intake efficiency by closing the EGR port according to the purpose of the present invention.

[0007]

In order to achieve the above object, in the present invention, in a multi-cylinder engine having an independent intake passage for each cylinder in an intake manifold,
An exhaust gas recirculation passage for a multi-cylinder engine, characterized in that an exhaust gas recirculation passage is connected to each of the intake passages, and a partition valve for opening and closing the exhaust gas recirculation passage is provided at an opening communicating with the intake passage. Provide a circulation device. It is also advantageous if the sluice valve is arranged to close the opening when the control valve of the exhaust gas recirculation device is closed.

[0008]

When the EGR valve is closed and EGR is turned off, the sluice valve is closed and the EGR port is closed.
By disconnecting the communication between the GR second passage and the intake manifold intake passage, the occurrence of a resonance phenomenon due to the intake pulsation effect that occurs between the intake passage and the EGR second passage is prevented, and at this time, Intake is performed in the passage with its original shape and length, ensuring high intake efficiency and high torque of the engine, while EGR is performed when the EGR valve is opened.
A sufficient amount of EGR is secured in the area.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a structure in the vicinity of intake and exhaust valves of an engine in which a sluice valve 30 according to the present invention is provided in an EGR port 24. The sluice valve 30 is provided at the position of the EGR port 24 shown in FIG. Other components of the engine in the present invention are the same as the structure shown in FIG. Therefore, the same parts as those in FIG.
Detailed explanation is omitted.

FIG. 1 (a) is a schematic vertical cross-sectional view of the structure near the intake / exhaust valve of the engine similar to FIG. 6, and FIG. 1 (b) is a schematic view of its top view (plan view). In the present invention, the EGR port 24 is provided with the sluice valve 30. The gate valve 30 is opened only when the EGR is used and is closed when the EGR is not used. That is, the EGR valve 22
When the valve is closed and EGR is off, the sluice valve 3
0 is closed, the EGR port 24 is closed, and the shape and length of the passage of the intake passage 2 in the intake manifold are the same as the case without the EGR port from the beginning, that is, the case of the engine shown in FIG. 5 described above. The performance thereof is similar to that of the engine indicated by the line V in FIG. 7, the original intake efficiency of the intake passage can be secured, and sufficient torque can be generated.

When the engine is under high load, high torque is required. For example, in comparison with the high intake efficiency requirement region H shown in FIG. 4, high intake efficiency is particularly required in the medium and low load regions of the engine. Therefore, there is no problem even if the EGR port is opened, and the region L shown in FIG. 4 becomes the EGR use region. In this region, the EGR valve 22 is opened and EGR is turned on, and the EGR gas flows into the intake passage 2 from the EGR port 24 via the second EGR passage.

Next, a specific structure of the sluice valve 30 which performs the above-mentioned operation will be described. First, FIG. 2 shows a first embodiment.
FIG. 2 is an enlarged view of a portion corresponding to the portion A of FIG.
As illustrated, the sluice valve 30 includes an EGR for each intake passage 2 of each cylinder by a spring 31 and a spring retainer plate 32.
It is attached to the second passage 23. Although the sluice valve is closed by the urging force of the spring when the engine is stopped, the engine starts and the EGR valve 22 opens.
R is turned on, and the EG is higher than the intake pressure in the intake passage 2.
When the pressure of the EGR gas in the R passage 23 becomes high and the pressure difference becomes larger than the urging force of the spring, the spring is compressed and the sluice valve 30 is opened.
Gas (exhaust gas) flows into the intake passage 2. This is the action in the L region of FIG.

When the engine continues to rotate and enters the high load region shown in FIG. 4H, the EGR valve 22 is closed and the EGR valve 22 is closed.
Turns off. For this reason, the EGR valve 22
Up to the GR port 24, that is, the second EGR passage 23
The internal pressure becomes lower than the internal pressure of the intake passage 2, and the urging force of the spring 21 closes the partition valve 30. Conventionally, even when the EGR valve 22 is closed at the time of a high load, the EGR port 24 has the structure shown in FIG.
The intake passage 2 described above in this part because the
A phenomenon that a resonance phenomenon occurs in the interior and thus deteriorates the intake efficiency occurs. In the present embodiment, the partition valve 30 blocks the second EGR passage and the intake passage 2, so that the above resonance phenomenon is prevented from occurring.

Next, FIG. 3 shows a second embodiment. The figure is an enlarged view of the portion A of FIG. 1 as in FIG. 2, but in this case, a diaphragm 33 is mounted on the EGR passage 23, and the sluice valve 30 is connected to this, and the diaphragm from the vacuum pipe 34 is used. 33 is operated to open and close the sluice valve. The negative pressure source at this time is the EGR valve 2
The negative pressure used for 2 etc. may be used. As a result, the EGR valve 22 is closed and E
When the GR is OFF, the sluice valve 30 is closed to prevent the resonance phenomenon in the intake passage 2 from occurring.

Regarding the structure of the sluice valve 30, in addition to the structure described above, it is sufficient if the EGR port 24 is closed when the EGR valve 22 is closed to prevent the deterioration of the intake efficiency. A means such as using an electromagnetic solenoid for opening / closing the EGR valve 22 or using a plate spring for opening / closing the EGR port in the EGR valve 22 is also conceivable.

As described above, a high intake efficiency is required while securing the EGR amount in the EGR region with a relatively simple structure without much modification to the structure near the conventional EGR port 24. It is possible to operate the engine in an optimal state near the load without causing a resonance phenomenon in the intake passage.

[0017]

By implementing the present invention, the EGR amount in the EGR region is sufficiently secured, and when the EGR valve is closed and EGR is OFF, the opening of the EGR port is conventionally communicated with the intake passage. Therefore, the occurrence of the resonance phenomenon occurring in the intake passage between the EGR passage and the intake valve is prevented, and high intake efficiency and high torque can be secured.
Further, the structure for the above can be made by a slight modification of the conventional structure, and the structure is relatively simple and advantageous in cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration in the vicinity of an intake / exhaust valve of an engine in which a sluice valve according to an embodiment of the present invention is provided in an EGR port, and FIG. 1A is a schematic vertical sectional view of a configuration in the vicinity of the intake / exhaust valve of the engine. FIG. 1B is a schematic diagram of the top view (plan view).

FIG. 2 is a first embodiment shown in an enlarged view of a portion A of FIG.
It is a block diagram of the gate valve by.

FIG. 3 is a second embodiment shown by an enlarged view of a portion A of FIG.
It is a block diagram of the gate valve by.

FIG. 4 is a torque-rotational speed diagram of the engine showing an outline of a use range and a non-use range of EGR.

FIG. 5 is a configuration diagram in the vicinity of an intake / exhaust valve of an engine that does not include a conventional EGR.

FIG. 6 is a configuration diagram in the vicinity of an intake / exhaust valve of an engine equipped with a conventional EGR.

7A and 7B are performance diagrams of a conventional engine having no EGR and an engine having the same. FIG. 7A is an intake efficiency-engine rotational speed diagram, and FIG. 7B is a torque-engine rotational speed diagram. is there.

[Explanation of symbols]

 1 ... Surge tank 2 ... Intake manifold intake passage 3 ... Intake valve 5 ... Exhaust valve 6 ... Exhaust manifold exhaust passage 10 ... Engine body 20 ... Exhaust gas recirculation device (EGR) 21 ... EGR first passage 22 ... EGR valve 23 ... EGR second passage 24 ... EGR port 30 ... Gate valve 31 ... Spring 33 ... Diaphragm

Claims (2)

[Claims] 1. In a multi-cylinder engine having an independent intake passage (2) for each cylinder in an intake manifold, an exhaust gas recirculation passage (23) is provided in each intake passage (2).
And a sluice valve (30) for opening and closing the exhaust gas recirculation passage (23) communicating with the intake passage (2) is provided in the exhaust of a multi-cylinder engine. Gas recirculation equipment. 2. The sluice valve (30) is configured to close the opening (24) when the control valve (22) of the exhaust gas recirculation device is closed. 2. An exhaust gas recirculation device for a multi-cylinder engine according to 1.