Connecting line between a compressor of an exhaust gas turbocharger flangedly connected at an exhaust gas manifold of an internal combustion engine and a suction pipe

A connecting line between a compressor of an exhaust gas turbocharger flangedly connected at the exhaust gas manifold of an internal combustion engine and a suction pipe which consists of a first line part secured at the suction pipe and of a second line part which is coupled with the exhaust gas turbocharger by way of plug-in coupling sections and with the first line part by way of a line bridge fixed at the engine and provided with plug-in coupling sections. The line bridge encloses a mixing space between its coupling sections, in which exhaust gases controlled by an exhaust gas valve are fed to the through-flowing charging air.

The present invention relates to a connecting line between a compressor of 
an exhaust gas turbocharger flangedly connected to the exhaust gas 
manifold of an internal combustion engine and a suction pipe, and more 
particularly to a connecting line assembled of two line sections. 
A connecting line assembled of two line sections is disclosed in the German 
Pat. No. 32 17 633. Both line sections are thereby fitted one within the 
other by way of coupling sections at the pipe ends in a manner to 
compensate for angles and tolerances. In a similar manner, the compressor 
outlet is also connected by way of coupling sections with the 
compressor-side end of the second line section. In order to avoid 
vibrations within the connecting area between the two line parts, the 
coupling sections which are fitted, one within the other, are additionally 
secured by two sheet metal shells bridging the sections and clamped fast 
at the pipe parts. Therebeyond, the first line section is secured at the 
valve cover by means of pipe clamps. 
It is thereby of disadvantage that the connecting area between two line 
sections is so fixed by the two sheet metal shells that an unconstrained, 
free compensation of tolerances and heat stresses is not possible. Added 
thereto is the fact that as a result of the fastening of the first line 
part at the valve cover, stresses occurring as a consequence of thermal 
expansions in the suction system are conducted into the valve cover by way 
of the pipe clamps. This is true also for the enormous heat expansions 
occurring within the area for the exhaust gas turbocharger which lead to 
an additional stress of the valve cover by reason of the limited 
compensation possibility in the connecting area of the two line parts. 
Finally, this connecting line further entails the disadvantage that no 
measures are provided for an exhaust gas recirculation. 
The present invention is therefore concerned with the task to improve the 
known connecting line in such a manner that in addition to a 
simplification in the assembly an unconstrained compensation of thermal 
expansions and manufacturing tolerances between the two line parts and an 
undisturbed recirculation of exhaust gases into the combustion air is 
achieved. 
The underlying problems are solved according to the present invention in 
that a line bridge fixed at the internal combustion engine is arranged 
between the first and second line part which includes at its longitudinal 
pipe discharge ends coupling sections for separately receiving the 
coupling sections on both line parts and which includes between the two 
coupling sections a mixing space with an overflow opening for the 
admixture of exhaust gas to the combustion air. 
The line bridge according to the present invention represents a connecting 
member on which the two line sections are retained separately from one 
another and thus decoupled from a vibration point of view. Additionally, 
it is achieved thereby that differing thermal expansions as well as 
manufacturing tolerances between the part on the suction pipe side and the 
part on the exhaust gas side of the connecting line are compensated 
far-reachingly automatically without mutual influence. By the locally 
fixed attachment of the line bridge at the engine, the connecting line 
includes a line section fixed at the engine which is suitable in 
particular for a vibration-free arrangement of an exhaust gas 
recirculating valve. As the line parts are merely plugged in or inserted 
at the coupling sections of the line bridge, a rapid and simple assembly 
of the connecting line is possible. 
According to another feature of the present invention, the coupling 
sections of the line bridge are constructed as pipe sockets while the pipe 
ends of the compressor outlet and of the first line section which are also 
constructed as pipe sockets are disposed axially opposite the pipe sockets 
of the line bridge coupling sections with an axial spacing while the pipe 
sockets disposed adjacent one another are coupled with one another by an 
inserted connecting sleeve, of which the connecting sleeve between the 
compressor outlet and the line bridge forms the second line part. The line 
sleeves may be provided at their longitudinal ends with sealing rings 
which abut against the inner wall of the pipe sockets. In addition to a 
simple assembly and a tight connection of all of the line parts, the 
possibility is achieved by the construction of the coupling sections in 
the manner described above for the compensation of a lateral offset 
between the line parts. 
An advantageous arrangement of the line bridge at the engine is achieved if 
the line bridge is secured at the longitudinal wall of the engine housing 
at the exhaust side by way of a bracket. 
It is possible to arrange the exhaust gas recirculation valve not only 
vibration-free but also at a relatively cool place of the connecting line 
if, according to a further feature of the present invention, the overflow 
opening forms the ends of a hollow flange connection formed on the housing 
of the mixing space on which is secured an exhaust gas recirculating 
valve. 
A good through-mixing of charging air and exhaust gas and a good pressure 
build-up in the connecting line is achieved according to the present 
invention if the flange connection is arranged tangentially to the mixing 
space and obliquely to the exhaust flow direction of the charging air at 
the housing thereof and if, starting from the compressor outlet, the line 
cross section of the two connecting sleeves and of the line bridge are 
constructed enlarged in a diffusor-like manner. 
A structurally simple connection of the exhaust gas recirculating valve and 
exhaust gas manifold can be achieved according to the present invention if 
the exhaust gas recirculating valve is connected by way of a flow line 
with a pipe connection at the exhaust gas manifold and if the flow line is 
assembled of a fixed pipe section and of a bellows pipe whereby the fixed 
pipe section is secured at the pipe connection by means of a clamp and the 
bellows pipe at the exhaust gas recirculating valve by means of a clamp.

Referring now to the single FIGURE of the drawing, an exhaust gas manifold 
3 is secured on an internal combustion engine, only partly illustrated and 
generally designated by reference numeral 1, at the exhaust side of the 
cylinder head 2; an exhaust gas turbocharger 4 is flangedly connected to 
the exhaust manifold 3. The charging air supplied by the compressor of the 
exhaust gas turbocharger 4 is conducted by way of a connecting line 
generally designated by reference numeral 5 to a suction pipe (not shown) 
arranged on the opposite side of the cylinder head. The connecting line 5 
which thereby leads over the valve cover 6 includes a first line part 7 
secure at the suction pipe, a second line part 8 which is inserted with a 
coupling section 9 in a coupling section of the compressor outlet 11 
constructed as pipe socket 10 and of a line bridge generally designated by 
reference numeral 12, by means of which the two manually facing line ends 
13 and 14 of the line parts 7 and 8 are coupled with each other. 
The line bridge 12 is fixedly supported at the exhaust-side longitudinal 
wall 16 of the engine housing by way of a bracket 15. For receiving the 
two line ends 13 and 14, the longitudinal ends of the line bridge 12 are 
constructed as pipe sockets 17 and 18; the line end 13 of the first line 
part 7 constructed as pipe socket 19 and by reason of the structurally 
near arrangement of the exhaust gas turbocharger to the line bridge 12, 
the pipe socket 10 of the compressor outlet 11 are disposed opposite the 
pipe sockets 17 and 18 with an axial spacing. The coupling of the mutually 
oppositely disposed pipe sockets 17 and 19 takes place by an inserted 
connecting sleeve 20 and between the pipe sockets 10 and 18 by the second 
line part 8 constructed at the same time as connecting sleeve which is 
plugged together with its line end 14 into the pipe socket 18. With an 
arrangement of the exhaust gas turbocharger 4 remote from the line bridge 
12, the connecting sleeve used as second line part can be correspondingly 
lengthened, or a separate matched line part can be inserted which is 
coupled with the line bridge 12 in the same manner as the line part 7. 
The connecting sleeves 8 and 20 thus form together with the pipe sockets 
10, 18, respectively, 17, 19 simple plug-in couplings by means of which 
the line parts 7 and 8 are retained separately at the line bridge 12. 
Thermal expansions and manufacturing tolerances which occur at the 
individual line parts 7 and 8 are compensated for by the two connecting 
sleeves 18 and 20 without mutual interference. 
In order that no charging air can escape to the outside at the coupling 
sections, sealing rings 21, 22, respectively, 23, 24 are arranged at the 
ends of the connecting sleeves 8 and 20 which are retained in annular 
grooves 25, 26, respectively, 27, 28 and abut each at the inside of the 
respective socket. 
For reducing the harmful components in the exhaust gas, the engine is 
equipped with an exhaust gas recirculation arranged at the connecting line 
5. The exhaust gas recirculation includes an exhaust gas recirculation 
valve 29 and a flow line generally designated by reference numeral 30 
leading from the recirculating valve 29 to the exhaust gas manifold 3. In 
order to that the exhaust gas recirculating valve 29 cannot be subjected 
to loads either by line vibrations or by different thermal expansions, 
respectively, tolerances, the exhaust gas recirculating valve 29 is 
arranged at the line bridge 12 fixed at the engine. For that purpose a 
hollow flange connection 31 is formed on the housing of the line bridge 12 
between the pipe sockets 17 and 18 on which is flangedly connected the 
exhaust gas recirculating valve 29. The flange connection 31 includes an 
overflow opening 32 discharging in the housing whereby the line section 
delimited by the housing forms a separate mixing space 33 in the 
connecting line. In order that a good mixing of exhaust gas and charging 
air is achieved in the mixing space, the flange connection 31 is arranged 
at the housing of the line bridge 12 tangentially to the mixing space 33 
and obliquely in the flow direction of the charging air. The flow line 30 
consists of a fixed pipe section 34 and of a bellows pipe 35 for the 
compensation of thermal expansions. The fixed pipe section 34 is thereby 
secured by means of a clamp 36 at the pipe connection 34 formed on the 
exhaust gas manifold 3 and the bellows pipe is secured by means of a clamp 
at the exhaust gas recirculating valve 29. 
While we have shown and described only one embodiment in accordance with 
the present invention, it is understood that the same is not limited 
thereto but is susceptible of numerous changes and modifications as known 
to those skilled in the art, and we therefore do not wish to be limited to 
the details shown and described herein, but intend to cover all such 
changes and modifications as are encompassed by the scope of the appended 
claims.