JPS5979062A - Exhaust gas re-circulating device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent adhesion of soot to an EGR valve or the like by a method wherein exhaust gas, flowing through an exhaust pipe, is pulified and the pulified exhaust gas is re-circulated into suction gas system. CONSTITUTION:A guide vane 5 is provided on the inner wall surface of the exhaust pipe 1 at a position nearer to the exhaust valve of a combustion chamber than an EGR control valve 4, as a means to provide the exhaust gas in the exhaust pipe 1 with a whirling current 6, while an exhaust gas introducing port 7 is provided at the center of the whirling current 6 of the exhaust gas so as to face the opening thereof against the flow of the exhaust gas. Carbon sludges in the exhaust gas are flowed along the wall of the pipe by the whirling current 6, therefore, the central part of the whirling current 6 is filled with the clean exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas recirculation device (hereinafter abbreviated as EGR) that recirculates part of the exhaust gas of an internal combustion engine to an intake system.

As shown in Fig. 1, the conventional E'GR has an exhaust pipe 1 and an intake pipe 2 connected through an exhaust recirculation passage 3, and an exhaust recirculation control valve 4 provided on the exhaust pipe 1 side is opened. The structure is such that part of the exhaust gas flowing through the exhaust pipe 1 is returned to the intake pipe 2.

The exhaust gas contains carbon, sludge, etc. generated during the combustion process, and in the conventional EGR, carbon adheres to the inner wall of the exhaust recirculation passage 3 and the valve seat or valve stem of the exhaust recirculation control valve 4. There are problems such as a decrease in the flow path area, resulting in insufficient EGR volume, and obstructing the smooth opening and closing function of the exhaust recirculation control valve.

Additionally, carbon, sludge, etc. entered the combustion chamber along with the intake air, leading to early wear of piston rings and early deterioration of lubricating oil.

In order to prevent the adhesion and accumulation of carbon and sludge on the valve seat and valve stem of the exhaust gas recirculation control valve, an EGR system equipped with a self-cleaning device that actively rotates and scrubs the valve stem was disclosed in Japanese Patent Application Laid-Open No. 53-322.
31, but in this case, the attached carbon and sludge are simply rubbed off to prevent accumulation, and the rubbed off carbon, sludge, and carbon and sludge in the recirculating exhaust gas are removed from the intake air. This will inevitably lead to early wear of the piston rings and early deterioration of the lubricating oil.

The present invention solves the above-mentioned conventional problems, and its feature is that the exhaust gas flowing through the exhaust pipe is purified, and the purified exhaust gas is returned to the intake system.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 4.

First, the main points of the present invention are to provide a means for imparting a swirling flow to the exhaust gas flowing through the exhaust pipe, and a means that communicates with the exhaust gas recirculation control valve and opposes the flow of the exhaust gas at the center position of the exhaust gas swirling flow. This is because an exhaust gas inlet is provided with the opening facing toward the front.

A specific example of this configuration will be explained with reference to FIGS. 2 and 3. As a means for imparting a swirling flow 6 to the exhaust gas in the exhaust pipe 1, the exhaust pipe 1 of the exhaust valve Tsukuda in the combustion chamber is located closer to the position of the exhaust recirculation control valve 4.
A guide vane 5 is provided on the inner surface, and an exhaust gas introduction lower is provided which communicates with the exhaust control valve 4 and has a recessed opening facing the flow of exhaust gas at the center position of the swirling flow 6 of the exhaust gas. be.

Fig. 4 shows the case of an internal combustion engine equipped with a turbocharger 8, where 9 is a turbine and 10 is a compressor.
The exhaust gas that has flowed out is turned into a swirling flow 6 by the turbine 9, which is obtained by providing the exhaust gas introduction lower 1 at the center of the swirling flow 6.

, since the present invention has the configuration as described above, the exhaust pipe 1.1
The exhaust gas flowing through a has a swirling flow 6, and carbon and sludge contained in the exhaust gas flow along the tube wall due to centrifugal force, and the center of the swirling flow 6 becomes clean exhaust gas. Therefore, the exhaust gas introduced into the exhaust gas recirculation passage 3 from the exhaust gas introduction lower which is provided with its opening facing the exhaust gas flow at the center of the swirling flow 6 has carbon and sludge removed. As a result, clean exhaust gas is returned to the intake system.

Therefore, according to the present invention, not only is it possible to eliminate the adhesion and accumulation of carbon and sludge on the valve seat of the exhaust recirculation control valve, the valve shaft, or the inner wall of the exhaust recirculation passage, but also the introduction of carbon and sludge into the combustion chamber is prevented. It has the advantage of preventing wear and early deterioration of lubricating oil. Also, it has a simple structure and can be put into practical use at low cost.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional general exhaust gas recirculation device, Fig. 2 is a sectional view of the device of the present invention, Fig. 3 is a sectional view of a main part showing a means for providing a swirling flow of exhaust gas, and Fig. 4 is a sectional view of a turbocharger. FIG. 2 is a cross-sectional view of a case where the device of the present invention is applied to an internal combustion engine. 1)・1a...Exhaust pipe, 2...Intake pipe, 3...Exhaust recirculation passage, 4...Exhaust recirculation control valve, 5...Guide vane, 6...Swirling flow, 7.・・Exhaust gas inlet, 8
Turbocharger.

Claims (1)

[Claims] an exhaust gas recirculation passage for recirculating a portion of the exhaust gas to the intake system;
An exhaust gas recirculation system for an internal combustion engine having an exhaust recirculation control valve includes means for imparting a swirling flow to exhaust gas flowing through an exhaust pipe; An exhaust gas recirculation device for an internal combustion engine, characterized by having an exhaust gas inlet opening facing the flow.