JPH07269363A - Exhaust manifold of internal combustion engine equipped with supercharger - Google Patents

Abstract

PURPOSE:To deter an exhaust valve from making an abnormal opening caused by exhaust pulses when an exhaust brake operates by mounting respective supercharges on the downstream end of a collection part to where an exhaust port of respective cylinders are connected, and cutting out a specific area of a partition wall partitioning passages for two lines at the downstream end side of the collection part. CONSTITUTION:In a six-cylinder engine, exhaust branch pipes 11 to 16 are aggregated at an eggregation part 17 by dividing them into a group of exhaust branch pipes 11 to 13 for the first to the third cylinders to where exhaust stroke is not connected and a group of exhaust branch pipes 14 to 16 for the forth to sixth cylinders. The downstream end of the aggregation part 17, where two superchargers driven separately by exhaust gas from passages 18, 19 are mounted, has a cutout part 23 of a specific area formed on a partition wall 22 partitioning passages 18, 19. Thus abnormal opening of an exhaust valve when exhaust brake is operated is prevented by making respective exhaust pulses pass through the cutout part 23 and interfere with one another.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust manifold for an internal combustion engine with a supercharger.

[0002]

2. Description of the Related Art In order to avoid the interference of exhaust gas discharged from each cylinder of an engine and to improve exhaust efficiency and supercharging efficiency,
Exhaust manifolds that collect the downstream ends of the branch parts connected to the exhaust ports of each cylinder into two channels with discontinuous exhaust strokes, and also install superchargers downstream of these two channels, respectively. is there.

By the way, in a diesel engine provided with such an exhaust manifold, the exhaust valve of the engine may be abnormally opened due to a pressure wave (pulse) of the exhaust when the exhaust brake that shuts off the exhaust pipe is operated. .

Therefore, when a gap at the upper position of the exhaust valve is detected, and when a gap larger than a predetermined value is detected, the shutter provided between the two passages of the exhaust manifold is opened to exhaust the pulse of the exhaust gas. Has been proposed to suppress the abnormal opening of the exhaust valve (Japanese Utility Model Laid-Open No. 5-75449).

[0005]

However, in the conventional example in which the shutter is provided in this way, a sensor and a drive device for the shutter are required, and an increase in cost cannot be avoided.

There is a partition wall between two channels of the exhaust manifold, in which a small slit is formed so as to prevent thermal fatigue due to thermal stress (Japanese Utility Model Laid-Open No. 1-174529). Such a slit cannot suppress abnormal opening of the exhaust valve due to exhaust pulses.

The present invention aims to solve such problems.

[0008]

SUMMARY OF THE INVENTION The present invention forms a collecting portion for collecting the downstream end of a branch portion connected to an exhaust port of each cylinder into two passages in which exhaust strokes are not continuous. 2 at the downstream end of the collecting section, corresponding to the two channels
In an exhaust manifold of an internal combustion engine with a supercharger to which two superchargers are attached, a partition wall that separates the flow paths of the two systems is cut out at a predetermined area on the downstream end side of the collecting portion.

[0009]

Therefore, when the exhaust brake of the engine provided with the exhaust manifold is operated, it is possible to prevent the exhaust pulses of each system from interfering with each other through the cutout portion of the partition wall and acting on the exhaust valve of the engine.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an exhaust manifold of a 6-cylinder diesel engine. Reference numerals 11 to 16 are exhaust branch pipes (branches) connected to exhaust ports of cylinders 1 to 6 of the engine, respectively. .

The exhaust branch pipes 11 to 16 are a group of the exhaust branch pipes 11 to 13 of the first cylinder to the third cylinder and the exhaust branch pipes 14 to 16 of the fourth cylinder to the sixth cylinder whose exhaust stroke is not continuous.
And are collected in the collecting unit 17.

In this case, the flow paths 18 and 19 are separated from each other, and the flow paths 18 and 1 are provided at the downstream end of the collecting portion 17.
Nine openings 20, 21 are formed.

Then, on the downstream end side of the collecting portion 17, a notch portion 2 having a predetermined area is formed in a partition wall 22 which separates the flow paths 18 and 19.
3 is provided.

The notch 23 is formed so that the partition wall 22 is notched by a predetermined length (for example, 5 mm) toward the upstream side with the width of the flow paths 18 and 19.

The flow path 1 is provided at the downstream end of the collecting portion 17.
Two superchargers are mounted, which are driven separately by the exhaust from 8,19.

With such a configuration, the exhaust pulse from the first cylinder to the third cylinder and the exhaust pulse from the fourth cylinder to the sixth cylinder have opposite phases as shown in FIG. Is guided through the flow paths 18 and 19 to drive the corresponding supercharger. However, when the exhaust pipe line (downstream of the supercharger) that operates the exhaust brake is shut off, the respective pulses of the exhaust gas flow through the flow path 18 , 19 through the cutouts 23 provided in the openings 20, 21 of the exhaust gas, 19, the amplitude of the exhaust pulse is reduced as shown in FIG.

This prevents the exhaust pulse from acting abnormally on the valve of the engine when the exhaust brake is activated.

If the notch 23 is not provided, the exhaust valve opens widely after the predetermined closing as shown in FIG. 5, but according to the present invention, the abnormal opening as shown in FIG. 6 can be suppressed.

Therefore, an excessive stress is not applied to the exhaust valve, high durability can be secured, and reliability is improved.

It should be noted that the flow paths 18, 19 are formed by the notch 23.
The thermal fatigue of the partition wall 22 between them is prevented, and the structure is simple because of the notch 23.

[0022]

As described above, according to the present invention, there is formed the collecting portion for collecting the downstream ends of the branch portions connected to the exhaust ports of the respective cylinders into the flow passages of two systems in which the exhaust strokes are not continuous. In an exhaust manifold of an internal combustion engine with a supercharger, in which two superchargers are installed at the downstream end of the gathering portion so as to correspond to the two passages, a partition wall that divides the two passages is provided at the gathering portion. Since the predetermined area is notched on the downstream end side of the engine, it is possible to prevent the exhaust valve from opening abnormally due to exhaust pulses when the exhaust brake of the engine is operated, and the durability and reliability of the exhaust valve are improved.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment.

FIG. 2 is a partial cross-sectional view.

FIG. 3 is a pressure waveform diagram of exhaust gas.

FIG. 4 is a pressure waveform diagram of exhaust gas when an exhaust brake is operated.

FIG. 5 is a characteristic diagram showing the behavior of the exhaust valve when there is no cutout portion.

FIG. 6 is a characteristic diagram showing the behavior of the exhaust valve of the embodiment.

[Explanation of symbols]

 11-16 Exhaust branch pipe 17 Collecting part 18,19 Flow path 20,21 Opening part 22 Partition wall 23 Notch part

Claims (1)

[Claims] 1. A collecting part for collecting the downstream end of a branch part connected to an exhaust port of each cylinder into a flow path of two systems in which exhaust strokes are not continuous and forming two collecting systems at the downstream end of this collecting part. In an exhaust manifold of an internal combustion engine with a supercharger, in which two superchargers are installed corresponding to the flow passages, the partition wall that divides the flow passages of the two systems is cut out in a predetermined area at the downstream end side of the collecting portion. An exhaust manifold for an internal combustion engine with a supercharger.