DE2127890B2 - COMBUSTION CHAMBER FOR AN EXHAUST GAS TURBOCHARGER - Google Patents

Description

40

The invention relates to a combustion chamber fed by air and exhaust gases in changing proportions an exhaust gas turbocharger for an internal combustion engine, -is with a bypass line for compressed air parallel to the internal combustion engine, the combustion chamber a flame tube closed at the upstream end and open at the downstream end, which has at least one fuel injector at its upstream end.

From DT PS 8 84 130 a combustion chamber is known which is arranged in the flow of exhaust gases from an internal combustion engine fed with precompression. in the combustion chamber, combustion air is fed to ^ combustion of the injected fuel. Since the exhaust gas is only supplied in the downstream area of the flame tube, a balance between exhaust gas and air cannot take place.

As is known, a combustion chamber can contain a flame tube, the closed end of which has at least one fuel injector, and the open end of which is in communication with the supply line of a turbine. An oxygen-rich gas is fed in near the closed end of the <- "> flame tube.

It is also known from OE-PS 2 30 523 at Burners inject an oxygen-rich end at the nozzle-side end of a combustion chamber and an end remote from the nozzle feed low-oxygen gas.

Compared to this prior art, the invention is based on the object of one of air and exhaust gases to design the combustion chamber fed in changing conditions in such a way that stable combustion despite considerable changing ratios between the air supplied to the combustion chamber and that of the combustion chamber supplied exhaust gases and despite significant changes in the combustion chamber supplied Amount of fuel is ensured.

According to the invention, this object is achieved in that the flame tube is provided with an axially continuous ", is surrounded by an outer jacket and closed at its ends annular chamber into which in the upstream area the bypass line for introducing compressed air and in the downstream area Area where the exhaust pipe for introducing exhaust gas opens, and that the annular chamber with the interior of the Flame tube is connected by openings distributed over its axial length.

In this way it is achieved that even with small amounts of air, the air supplied is stoichiometric Burning the amount of fuel injected at the same end of the combustion chamber is sufficient even if the latter has its greatest possible value for such gaits. The engine exhaust, which is most of the Filling the annular chamber, seen from the downstream end, causes the necessary cooling of the combustion gases of the fuel injected by the injector. When the amount of air is proportionate large and the amount of exhaust gases is relatively small, the air, which then makes up the largest part of the annular chamber, seen from the upstream end, fills up the combustion of the injected fuel in the flame tube itself, if the amount of fuel supplied is as low as possible in such gaits, and At the same time, this air cools the combustion gases generated during combustion. By doing Annular space, which surrounds the flame tube, forms a boundary between exhaust gas and fresh air in accordance with the fresh air conveyed and in accordance with that for the respective operating state of the Internal combustion engine in the combustion chamber required fresh air changed. Under these circumstances However, the combustion remains despite the strongly changing proportions between fresh air and Exhaust gases and stable despite the variability of the amount of fuel injected. It almost forms a constant, stoichometric equilibrium in the mixture of fresh air and exhaust gas. Which The amount of fuel fed in that changes is independent of the proportions of fresh air and exhaust.

The invention is explained in more detail below with reference to the drawing using examples.

F i g. 1 is a schematic sectional view of an in accordance with FIG a first embodiment of the invention formed combustion chamber;

F i g. 2 is a schematic sectional view of an according to FIG a second embodiment of the invention formed combustion chamber;

F i g. 3 shows a pre-compression fed diesel engine with a combustion chamber according to the invention is equipped.

The in F i g. The combustion chamber shown in FIGS. 1 and 2 has a flame tube 1. The combustion chamber has an am

upstream end 2 closed and at the downstream end End 4 open flame tube 1. At the closed or upstream end 2 of the flame tube 1, a fuel injection door 3 is provided. The downstream end 4 opens into a gas mixture line supplying its point of use.

If this combustion chamber is used to heat the exhaust gases by an exhaust gas turbocharger 6 with precompression powered diesel engine 5 is used, the downstream end 4 of the flame tube 1 opens directly into the distributor of the turbine 6a of the turbocharger.

The flame tube 1 is surrounded by an axially continuous annular chamber 8a which is delimited by an outer jacket 8 and closed at its ends. The bypass line 9 for introducing compressed air opens into the king chamber 8a in the upstream area, and the exhaust line 10 for introducing exhaust gases opens in the downstream area. The annular chamber 8a is connected to the interior of the flame tube 1 through openings 7 distributed over its axial length. The bypass line 9 feeds air coming from the compressor 6b of the turbocharger into the upstream region of the annular chamber 8a. Exhaust gases coming from the diesel engine 5 are introduced into the downstream region of the annular chamber 8a via the exhaust pipe 10.

Although the outer jacket 8 can surround the flame tube 1 at the upstream end 2, it closes the outer jacket 8 is preferably close to the flame tube 1 at the upstream end 2.

In the case of the FIGS. 1 and 2, the bypass line 9 follows the outer jacket 8 via a distribution space ί 1.

The exhaust line 10 closes at the in FIG. 1 on the outer jacket 8 via a distribution space 12.

The exhaust pipe 10 can, however, also according to the embodiment shown in FIG Connect annular exhaust gas chamber 13 via a distribution space 14, the chamber 13 the Outer jacket 8 at the upstream end 4 of the flame tube 1, which is closed, surrounds, with on Circumference of the jacket distributed in the axial direction 15 are arranged axially offset from one another to allow the gases to pass through from the annular exhaust gas chamber 13 to enable the annular chamber 8a delimited by the outer jacket. This arrangement ensures a better distribution of the exhaust gases in the annular chamber 8a surrounding the outer casing 8.

The flame tube 1 preferably has axial slots 16 between its upstream combustion zone 1 a and the downstream mixing zone 1 b. In this way, the wall of the mixing zone 16 is cooled with air.

The inventive design of a fed by air and exhaust gases in changing ratios Combustion chamber ensures stable combustion in the combustion chamber, which depends on the ratio between the amount of fuel gas and the amount of fresh air is independent, although this ratio is with a Pre-compression fed diesel engine changes significantly.

For this reason, the power of the compressor of the high compression unit can only be used as a function of the diesel engine and the stoichometric combustion conditions of the combustion chamber can be detected while in a known combustion chamber it would have been necessary to increase the performance of the compressor with a significant safety factor to ensure combustion. This would have changed both the dimensions of the pre-compression unit as well as its price increases.

For this purpose 2 sheets of drawings

Claims (3)

Patent claims: 1. Combustion chamber for an exhaust gas turbocharger fed by air and exhaust gases in changing proportions for an internal combustion engine, with a bypass line parallel to the isolating engine for compressed air, with the combustion chamber closed at the upstream end and at the downstream end has an open flame tube. at least one fuel injector on his having upstream end, thereby characterized in that the flame tube is axially continuous through an outer jacket (8) limited and closed at its ends annular chamber (8a) is surrounded, in the upstream Area the bypass line (9) for introducing compressed air and in the downstream Area where the exhaust pipe (10) for introducing exhaust gas opens, and that the annular chamber (8a) with the interior of the flame tube (1) through openings (7) distributed over its axial length stands. 2. Combustion chamber according to claim 1, characterized in that the limited by the jacket (8) Annular chamber (8a) in turn in the part of its length which is the open end of the flame tube is adjacent, is surrounded by an annular exhaust chamber (13) into which the exhaust pipe (10) opens, and that the two annular chambers through openings (15) distributed in the axial direction in the jacket (8), which separates the two annular chambers from one another, are in communication with one another. 3. Combustion chamber according to claim 1 or 2, characterized in that the flame tube (1) between its upstream combustion zone (la) and the downstream mixing zone (ib) has axial slots (16).