DE4235075C2 - Intake line of a multi-cylinder internal combustion engine - Google Patents

Description

The invention relates to an intake line of a multi-cylinder Internal combustion engine according to the preamble of the claim 1.

An intake line of the generic type is from DE-PS 41 09 436 known. In contrast, from DE-OS 39 30 243 continues an exhaust gas recirculation device for a multi-cylinder combustion Engine known, the exhaust pipe of a cylinder forms the exhaust gas recirculation line with a connecting line from branch off the individual lines, each in the inlet channels of the individual cylinder open. A line from a main line branch and branches into it at another point, thus a By disclosed for example in DE-PS 41 09 436 pass line, is not from the present exhaust gas recirculation removable. Via the known exhaust gas recirculation line sucked fresh air heated gas mixture supplied, however be this gas mixture consists almost entirely of exhaust gas and not from essentially hot fresh air. Therefore, the reset exhaust gas was not equivalent to the air warmed by the burner represents, especially since the supply of the exhaust gas in the exhaust gas recirculation only used to reduce nitrogen oxide emissions becomes. In exhaust gas recirculation, there is an impact in the exhaust cycle exhaust gas is introduced from a predetermined cylinder, which manifests itself in strong pressure pulsations in the pipe system acts so that the cylinder, the intake valve just at maxi times exhaust gas pressure is available, an above-average exhaust gas rate is supplied. Thus no equal distribution of the Abga ses achieved on the following intake cylinders what to uneven combustion of the individual cylinders leads each other.  

Furthermore, it can be seen from GB-PS 13 25 992, lead to fresh air heated in each inlet channel of a multi-cylinder internal combustion engine via one line each from the exhaust manifold. In the warm-up phase, however, the exhaust manifold is still cold, so that in the phase in which the intake air preheating would be most important for an improved engine operation, no heating of the air can be generated. In addition, since the intake air is heated during the entire engine operation when the exhaust manifold is warm, the cylinders are filled with the fuel / air mixture much worse, which leads to reduced performance. In addition, the increase in the temperature of the combustion process due to the heating of the intake air increases the NO _x formation and thus the pollutant emission.

The invention has for its object a generic To further develop the intake pipe in such a way that it warms up phase of the engine of the intake air on with exhaust gas ver set heated gas mixture can be supplied without an Un equal distribution in the composition of the mixture for the single cylinder of the internal combustion engine occurs.

The object is according to the invention in that in claim 1 specified characteristic features solved.

The bypass line is in single line downstream of the burner branches, of which at least one in each Inlet channel of the engine opens.

This ensures uniform mixing of the gas mixture the bypass line with the fresh air drawn in, with each inlet channel an equal share in the in the Bypass line generated mixture amount at the same time with the same composition is supplied, after which the cremation processes in the individual cylinders run uniformly. Because of this uniformity, the pollutant emissions  greatly reduced in the exhaust gas.

In a further advantageous embodiment according to claim 3 is fuel upstream of the branching of the individual lines Cold start enrichment of the bypass line can be supplied. Through the early admixture in the bypass line maintains power fabric more time to introduce into the cylinder Nebulize internal combustion engine, resulting in improved diam with the intake air. Since in the bypass line Partial flow of fresh air is heated, condensation of the fuel on the inner walls of the lines largely prevented.

In a particularly advantageous embodiment according to claim 4 the bypass line has a swirl chamber for the gasge mix up, from which the individual lines are branched off. In the The swirling chamber becomes the inflowing exhaust gas force mixed air-mixture and homogenized, creating a same composition of fresh air for each inlet duct The mixture to be supplied is optimally guaranteed and thus an in all cylinders have the same combustion.

The following description of the drawing shows two versions tion examples of the invention explained.

It shows:

Fig. 1, the suction duct according to the invention with a downstream of the burner in cast-individual lines passing over Bypasslei tung in a section,

Fig. 2 shows the suction pipe of Fig. 1, in a section along the line II-II

Fig. 3 shows schematically the intake line according to the invention with a downstream of the burner in free-running individual lines via the bypass line, which has a fuel injection nozzle for cold start enrichment and a swirl chamber and to which an exhaust gas recirculation line is connected.

In Fig. 1, an intake pipe 1 of an internal combustion engine, not described here, is shown, in which a throttle valve 2 is arranged to control the amount of suction air flowing in the direction of the arrow.

Upstream of the throttle valve 2 , a bypass line 3 is branched off from the intake line 1 , in which a throttle valve 4 is arranged, which controls an opening 5 of the intake line 1 into the bypass line 3 .

Downstream of the throttle valve 4 , a fuel injector 6 and then a flame holder 7 with a spark plug 8 are arranged in the bypass line 3 , which together form a burner 9 . The bypass line 3 runs in a meandering manner, the bypass line 3 and the suction line 1 having a common wall 10 .

Downstream of the burner 9 , the bypass line 3 branches into a plurality of individual lines 11 , as is particularly illustrated in FIG. 2. The individual lines 11 are cast on the wall 10 of the intake line 1 . Each inlet channel 12 of the internal combustion engine is assigned a single line 11 , which has an outflow side opening port 13 in the inlet channel 12 at the same location.

In the individual lines 11 , the gas mixture is excited by the gas changes in the inlet channels 12 to vibrations, which act back through the orifices 13 in the inlet channels 12 , which causes the pressure waves of the intake air that form there and thus the vibration lengths suitable for charging the internal combustion engine be disturbed. In order to nevertheless ensure that the corresponding oscillation lengths form, the orifices 13 are arranged very close to the inlet opening of the inlet channels 12 , so that the disturbance torque in the entire inlet channel is largely eliminated.

The individual lines 11 have the same length and same cross-section, as well as the same flow resistance, whereby to compensate for the different distances between the bypass line 3 and the orifices 13 and thus to ensure the same length, the individual lines 11 a with - starting from the greatest distance - shorter distances winding.

Downstream of the orifices 13 , a fuel injector 14 is arranged in each inlet channel 12 to form a fuel-air mixture.

In a variant of the intake line 1 according to the invention which differs from FIG. 1, an exhaust gas recirculation line 15 is connected in FIG. 3 to the bypass line 3 downstream of the burner 9 .

In the further course of the bypass line 3 , an additional fuel injector 16 for cold start enrichment is angeord net. Finally, the bypass line 3 flows downstream of the fuel injector 16 into a swirl chamber 17 , from which the individual lines 11 to the inlet channels 12 of an internal combustion engine 18 shown here with four cylinders 19 branch off. The individual lines 11 run freely.

Due to the different lengths of the individual lines 11 , which result from the different structural distances between the swirl chamber 17 and the inlet channels 12 , in order to ensure the same oscillation lengths of the gas mixture flowing through in each individual line 11, the longer individual lines are compared to the shortest individual line extends a cross section immediately adjacent to the swirl chamber 17 .

As a result of the lower flow velocity in this section which is enlarged in cross section, the oscillation length in the longer individual lines is reduced. By a suitable adaptation of the size of the cross-sectional expansions to the length of the individual lines, the same reduced oscillation lengths for each individual line 11 and thus the same flow conditions can be achieved in each inlet channel 12 .

In the warm-up phase of the internal combustion engine 18 , with the throttle valve 2 at least partially closed, at least a partial flow of the fresh air flowing in the intake line 1 is diverted into the bypass line 3 and fed downstream of the throttle valve 4 to a burner 9 , which heats the fresh air and adds exhaust gas.

In this case, a flame extinguisher 20 is provided between the burner 9 and the nozzle 16 in the bypass line 3, which prevents the flame of the burner 9 from meeting with the fuel sprayed from the nozzle 16 . The flame extinguisher can consist, for example, of a wire mesh which, due to its large area, creates a wall quenching effect.

The warm air-exhaust gas mixture is further supplied via the exhaust gas recirculation line 15 and 16 fuel is added by means of the fuel injection nozzle. The entire mixture is mixed and homogenized in the swirling chamber 17 .

The homogeneous mixture flows through the individual lines 11 through the orifices 13 into the inlet channels 12 and is mixed with the main stream of fresh air drawn in through the intake line 1 past the throttle valve 2 and fed to the cylinders 19 of the internal combustion engine 18 .

Claims (5)

1. Intake line of a multi-cylinder internal combustion engine having a plurality of inlet channels, a bypass line branching off from the intake line, via which a gas mixture heated by a burner can be supplied to the fresh air flowing in the intake line, characterized in that the bypass line ( 3 ) is downstream of the burner ( 9 ) is branched into individual lines ( 11 ), of which at least one opens into an inlet channel ( 12 ) of the internal combustion engine ( 18 ). 2. Intake line according to one of claims 1, characterized in that an exhaust gas recirculation line ( 15 ) is connected to the bypass line ( 3 ) upstream of the branching of the one cell lines ( 11 ). 3. Intake line according to one of claims 1 to 2, characterized in that upstream of the branching of the individual lines ( 11 ) fuel for cold start enrichment of the bypass line ( 3 ) can be fed. 4. Intake line according to one of claims 2 or 3, characterized in that the bypass line ( 3 ) has a swirl chamber ( 17 ) for the gas mixture, from which the individual lines ( 11 ) are branched off. 5. Suction line according to one of claims 1 to 4, characterized in that a flame extinguisher ( 20 ) is provided in the bypass line ( 3 ) between the burner ( 9 ) and a fuel injector ( 16 ) arranged downstream of the burner ( 9 ).