Afterburner Apparatus For Engine Exhaust Gas

Abstract

The exhaust pipes from the cylinders of an internal combustion engine lead to an afterburner chamber and thence to a muffler, and either a separate pipe or one of the exhaust pipes constitutes a bypass conduit leading from the afterburner chamber to the muffler. A control valve device regulates the flow through the exhaust pipes, with the exception of the bypass conduit, whereby the exhaust gases from the cylinders can flow directly therefrom to the muffler or can be diverted through the afterburner chamber and bypass conduit to the muffler. The valve device is closed when the engine is at low-power output and open when the engine is at high-power output.

Description

BRIEF SUMMARY OF THE INVENTION

There has been hither to known an afterburner apparatus in which the exhaust gases of an internal combustion engine are admitted into an afterburner chamber for being burnt again so that its unburned ingredients are removed therefrom. The afterburner chamber, in this case, is usually of a sufficient volume such that, at the time of high-output power of the engine, the chamber does not become a resistance to the exhaust gas flow and thereby bring about lowering of the engine output power. With an afterburner chamber of large volume, however, at the time of engine starting or engine low-output power, it is difficult to maintain the interior of the chamber at a high temperature and the desired afterburner operation is difficult to perform. Additionally, at the time of engine starting, the engine is supplied with a comparatively large amount of fuel for insuring starting so that unburned ingredients are produced in large amounts. Therefore, nonoperation of the afterburner chamber at this time is especially undesirable.

An object of this invention is to provide afterburner apparatus free from the above defects, and characterized in that respective cylinders of an internal combustion engine are in communication with a muffler through a first passage comprising their respective exhaust pipes and having valve means interposed therein, and, in parallel therewith, a second passage comprising a single common afterburner chamber and a bypass conduit pipe connected to the chamber. The valve means is connected with a throttle valve of the engine through a connecting rod so that the valve means is closed when the throttle valve is open a comparatively small degree, but is opened when the throttle valve is open a comparatively large degree. The valve means may be a single valve common to all the exhaust pipes, but the valve means can also be an associated plurality of valves, one for each exhaust pipe.

According to a feature of this invention, at least one of the exhaust pipes can be utilized to serve also as a bypass conduit pipe connected between the after burner chamber and the muffler, and thus the apparatus can be simple in construction and small in size. This can be achieved only in that at least one of the exhaust pipes is not controlled by the valve means.

BRIEF DESCRIPTION OF THE DRAWING:

FIG. 1 is a diagrammatic illustration partly in section of one embodiment according to this invention,

FIG. 2 is a detailed sectional view of an afterburner chamber portion of the embodiment of FIG. 1,

FIG. 3 is a sectional view taken along line III-III in FIG. 2,

FIG. 4 is a diagrammatic illustration showing a modification of the above embodiment,

FIG. 5 is a diagrammatic illustration of another embodiment according to this invention, and

FIGS. 6 and 7 are diagrammatic illustrations showing modifications thereof.

DETAILED DESCRIPTION

Referring first to FIGS. 1 to 3 showing one embodiment of this invention, numeral 1 denotes an internal combustion engine comprising several cylinders, for example, four cylinders 2, 3, 4, 5. Respective exhaust pipes 6, 7, 8, 9 extending from cylinders 2, 3, 4, 5 are joined together at one end into a single common conduit pipe 10 containing a valve 11 and pipe 10 in turn is connected to a muffler 12, such that elements 6--11 form a first passage A between the engine 1 and the muffler 12. On the other hand, the exhaust pipes 6, 7, 8, 9 are provided with respective small apertures 13, 14, 15, 16 in their respective side surfaces near the cylinders and the apertures open into a single common afterburner chamber 17 of comparatively small volume. Chamber 17 is connected to the muffler 12 through a bypass conduit pipe 18, thus providing a second passage B between the engine 1 and the muffler 12 in parallel with the first passage A. Numeral 19 denotes a small aperture in the side surface of the base end portion of the bypass conduit pipe 18 for providing communication between the pipe 18 and the chamber 17.

The valve 11 and a throttle valve 20 of the engine 1 are connected together by a connecting rod 21 so that the valve 11 is closed when the valve 20 is open a comparatively small degree (engine low-output power operation) but is opened when the valve 20 is open a comparatively large degree (engine high-output power operation). Numeral 22 is a throttle wire.

As clearly shown in FIGS. 2 and 3, the exhaust pipes 6, 7, 8, 9 and the bypass conduit pipe 18, are arranged within the afterburner chamber 17 so that the chamber 17 is increased in its mechanical strength and the small apertures 13, 14, 15, 16 are disposed in two rows in alternating directions to provide a zigzag relation for decreasing mutual interference as much as possible. An outer jacket 23 of the chamber 17 is composed of upper and lower half portions detachably joined together by bolts 24, to facilitate replacement of an interior heat insulating material 25.

The operation of this embodiment is as follows:

If the valve 11 is opened, the first passage A is open. Accordingly, the exhaust gases from the engine 1 are led to the muffler 12 chiefly through the passage A. Therefore, the chamber 17 does not constitute a flow resistance even if the chamber is constructed to be of a comparatively small volume. If the valve 11 is closed, the first passage A becomes closed, and accordingly, the exhaust gases from the engine 1 are led to the muffler 12 through the second passage B, and therefore through the afterburner chamber 17. Thus, unburned ingredients in the exhaust gas are subjected to a purification treatment in the chamber 17.

Consequently, in the apparatus according to the invention, the first passage and the second passage can be selectively utilized by the operation of the valve 11. In the case of operation of a vehicle such as a motorcar or the like, at the time of engine high-output power operation, which is comparatively infrequent and during which the amount of unburned ingredients contained in the exhaust gas is comparatively low, the first passage is utilized for discharging the exhaust gases and thus the use of the afterburner chamber is eliminated. Accordingly, the deficiency that the chamber functions as a flow resistance to cause the lowering of engine output power is avoided even if the chamber is of a comparatively small volume. On the other hand, at the time of engine starting or engine low-output power where unburned ingredients are included in large quantities in the exhaust gases, the second passage B, and thereby the afterburner chamber 17 is utilized. Accordingly, a predetermined afterburner operation can be positively effected even afterburner the after chamber is of a comparatively small volume.

The embodiment of FIGS. 1 to 3 can be modified as shown in FIG. 4. Namely, in the embodiment in FIGS. 1 to 3, the valve means is is single valve 11 common to all the exhaust pipes 6, 7, 8, 9 but the valve means can be constituted as an associated plurality of valves 11a, 11b, 11c, 11d one for each exhaust pipe as shown in FIG. 4. It will be easily understood that substantially the same operation can be effected in this embodiment.

According to another modification, the bypass conduit pipe 18 in the above embodiments can be eliminated and thereby the apparatus can be simplified and be made more compact. This can be achieved by the arrangement as shown in FIG. 5. Namely, as seen in FIG. 5, any one of the exhaust pipes, for example, the pipe 9 on the extreme right can be selected to serve as a bypass conduit, and the valve 11 controls only the remaining pipes 6, 7, 8.

The operation of the embodiment of FIG. 5 as follows:

If the valve 11 is opened, the exhaust gas from each cylinder 2, 3, 4, 5 is led to the muffler 12 through their respective exhaust pipes 6, 7, 8, 9 so that the exhaust gas flow is not subjected to a flow resistance by the presence of the afterburner chamber 17. In this case the selected pipe 9 which is not controlled by the valve 11 operates similar to the remaining pipes 6, 7, 8. If, however, the valve 11 is closed, the exhaust gases from cylinders 2, 3, 4 are led into the chamber 17 through respective small apertures 13, 14, 15 to be burned again and then led to muffler 12 through the pipe 9.

Thus, in this embodiment, at least one pipe selected from all the exhaust pipes is designed not to be controlled by the valve 11, so that the selected pipe can act in almost the same manner as the remaining pipes when the valve 11 is open, whereas the pipe 9 acts as a bypass pipe connecting the chamber and the muffler when the valve 11 is closed. Thus, it is not necessary to provide a separate bypass conduit and the apparatus can be simplified and made compact.

It will be easily understood that, instead of the single valve 11 in the embodiment of FIG. 5, three associated valves 11a, 11b, 11c or two associated valves 11a, 11b can be used as shown in FIGS. 6 and 7 respectively.

Claims

What I claim is:

1. An afterburner apparatus for the exhaust gases from respective cylinders of an internal combustion engine in combination with a muffler, said apparatus comprising an afterburner chamber, conduit mean joining said cylinders and said muffler and providing a first passage for exhaust gases directly from said cylinders to said muffler and a second passage in parallel with said first passage and leading through said afterburner chamber to said muffler, said first passage opening into said afterburner chamber, and valve means in said first passage between the afterburner chamber and the muffler for selectively opening and closing said first passage which also controls flow of exhaust gases from the first passage into the afterburner chamber and second passage, said conduit means comprising exhaust pipes extending from respective cylinders through said chamber, said pipes having apertures which open into said chamber.

2. Apparatus as claimed in claim 1 wherein said apertures in the pipes face in alternating directions within the chamber to avoid mutual interference.

3. Apparatus as claimed in claim 1 wherein said exhaust pipes form a common junction between said chamber and said muffler and said valve means comprises a single valve common to all the exhaust pipes, said second passage including a bypass conduit extending from said chamber to said muffler.

4. Apparatus as claimed in claim 1 wherein said valve means comprises a plurality of valves, one in each exhaust pipe, said second passage including a bypass conduit extending from said chamber to said muffler.

5. Apparatus as claimed in claim 1 wherein one of said exhaust pipes is a bypass conduit included in said second passage, the remaining exhaust pipes collectively defining said first passage.

6. Apparatus as claimed in claim 5 wherein said valve means comprises a single valve common to said remaining exhaust pipes.

7. Apparatus as claimed in claim 5 wherein said valve means comprises a separate valve in each of said remaining exhaust pipes.

8. Apparatus as claimed in claim 5 wherein at least one of said remaining pipes is joined with said bypass conduit at a juncture between the chamber and said muffler, said valve means comprising a separate valve in said at least one remaining pipe before the juncture thereof with said bypass conduit.