JPH0367014A - Method of reactivating particle filter arranged in exhaust gas pipeline of supercharged internal-combustion engine - Google Patents

Abstract

PURPOSE: To regenerate a particle filter in a full load range by directly introducing roughly all the exhaust gas main current to the particle filter in a low load range while throttling a suction air current or heating it, and introducing a partial current from the exhaust gas main current directly to the particle filter in the upstream of a turbine in a high load range. CONSTITUTION: In a low load range under an average load range of an internal combustion engine, roughly all the exhaust gas main current bypasses a turbine 4 of a turbo supercharger 2 to be directly introduced through exhaust gas pipings 3 to a particle filter 5. In this case, exhaust gas temperature is maintained at a necessary value for regeneration of the particle filter by throttling a bypass valve 10 provided in supercharged air pipings 9 or heating it. In a total load range from the average load range, an exhaust gas partial current is directly introduced to the filter 5 through a bypass valve 7 and bypass pipings 6 in the upstream of the turbine 4 from the exhaust gas main current supplied to it, thereby temperature of the total exhaust gas current supplied to the filter 5 is controlled to be a necessary value for regeneration of it.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a particle filter disposed in the exhaust gas piping of a supercharged internal combustion engine downstream of an exhaust gas turbocharger, and a particle filter that reaches the particle filter. A method of regeneration by increasing the temperature of the exhaust gas in relation to operating parameters, in which at least a part of the main exhaust gas leaving the internal combustion engine is guided directly to the particle filter, bypassing the turbine of the exhaust gas turbocharger. (method according to the generic part of claim 1).

[Prior Art] Such a method is already known from European Patent No. A-260031. However, this known method does not permit the expansion of the exhaust gas in the turbine of the exhaust gas turbocharger, especially in the low load and low speed ranges, since in the operating ranges mentioned above for diesel internal combustion engines, the already low exhaust gas temperature is Therefore, there is a drawback that the exhaust gas temperature required for regeneration of the soot filter cannot be obtained.

OBJECT OF THE INVENTION The object of the invention is to improve a method of the type mentioned at the outset in such a way that the particle filter can be regenerated at as many operating points of the internal combustion engine as possible.

[Means for Solving the Problems] According to the present invention, this object is achieved by using a method of the type mentioned at the outset, in which almost the entire main stream of exhaust gas is transferred to the exhaust gas turbo supercharger in a low load range below the average load range of the internal combustion engine. By bypassing the machine turbine and directing directly to the particle filter, by simultaneously throttling and/or heating the suction air stream, the exhaust gas temperature is maintained at the value required for particle filter regeneration and is kept within the average load range. Up to the full load range, upstream of the turbine of the exhaust gas turbocharger, an exhaust gas partial stream is branched off from the exhaust gas main stream fed to it and directed directly to a particle filter, in which the exhaust gas partial stream is This is achieved in that the temperature of the total exhaust gas stream fed to the filter is quickly controlled to the value required for its regeneration.

[Effect of the Invention J] The exhaust gas that is guided around the turbine of the exhaust gas turbocharger does not expand within the turbine, so its temperature decreases only slightly. In conjunction with the simultaneous increase in the combustion process temperature by throttling and/or heating the intake air, sufficient exhaust gas temperatures for self-regeneration of the particulate filter are obtained even at low load and low speed ranges. Above the average load range, on the other hand, control of the intake air is no longer taken into account. In order to always ensure a sufficiently high temperature of the exhaust gas stream reaching the particle filter in this case, only the boost pressure required for the actual operating point of the internal combustion engine is adjusted, i.e. only a portion of the exhaust gas is transferred to the turbine. guided through. Since the remaining exhaust gas stream is bypassed by the turbine, it does not expand and therefore does not drop in temperature, and even in this operating range the particulate filter is regenerated satisfactorily. In the entire load range, the exhaust gas temperature level is so high that regeneration of the particle filter takes place without additional measures to increase the exhaust gas temperature.

The reflux of the exhaust gas proposed in claim 2 has the advantage that nitrogen oxides in the exhaust gas are additionally reduced, in which case the reflux pipe is connected upstream of the particle filter. The branching prevents ceramic particles that may have separated from the soot filter from reaching the combustion chamber of the internal combustion engine.

Advantageous devices for carrying out the method according to the invention are described in claims 3 to 8 of the appended claims.

[Embodiments] The present invention will be described in detail below with reference to embodiments shown in the drawings.

In FIG. 1, l is a diesel internal combustion engine supplied with air by an exhaust gas turbocharger 2. In FIG. A soot filter 5 is disposed in the exhaust gas pipe 3 downstream of the turbine 4 of the exhaust gas turbocharger 2 . turbine 4
A bypass pipe 6 is branched from the exhaust gas pipe 3 upstream of the exhaust gas pipe 3. The through-flow cross-sectional area of the bypass pipe 6 can be changed by a bypass valve 7 arranged at the branch point. The bypass pipe 6 opens again into the exhaust gas pipe 3 between the turbine 4 and the soot filter 5. A throttle valve 10 is disposed in a supercharging air pipe 9 extending downstream of the compressor 8 of the exhaust gas turbocharger 2 . The flow cross-sectional area of the supercharged air pipe 9 can be controlled by this throttle valve lO. The exhaust gas pipe 3 and the supercharged air pipe 9 connect to the turbine 4
They are connected to each other by an exhaust gas recirculation pipe 11 that branches on the upstream side of the exhaust gas recirculation pipe 11 . This exhaust gas recirculation pipe 11 opens into the supercharging air pipe 9 on the downstream side of the throttle valve 10, and its recirculation cross-sectional area is equal to the exhaust gas recirculation valve 12 provided at the branch point.
can be controlled by The exhaust gas recirculation pipe 11 connects to the turbine 4
It is possible to branch from between the soot filter 5 and the soot filter 5.

In any case, it is ensured that particles separated from the ceramic body of the soot filter 5 do not reach the combustion chamber of the internal combustion engine 1 .

A suction pipe 13 extending upstream of the compressor 8 is provided with an air amount detector 15 in addition to an air filter 14 . A supercharging pressure detector 16 is provided in the supercharging air pipe 9 downstream of the throttle valve 10 .

Both these detectors 15.16 are connected to the measured value wiring 17.18
It is connected to the electronic control unit 19 via. This control unit 19 generates an adjustment value signal as a function of the measured value signal applied thereto. The first adjustment value signal controls the bypass valve 7 via the control wiring 21, and the second adjustment value signal controls the throttle valve IO via the control wiring 21.

The third adjustment value signal controls the exhaust gas recirculation valve 12 via the control wiring 22 .

The control of these three valves 7.10, 12 takes place according to the diagram 23 (Pme=f (n)) shown in FIG. The effective average pressure Pme plotted on the vertical axis is the magnitude relative to the load of the internal combustion engine, and n plotted on the horizontal axis is the rotation speed of the internal combustion engine.

Below the first threshold value function 24, which is related to the rotational speed for a load of t=ta, ie in the low load range of the average load range of the internal combustion engine, the bypass valve 7 is completely open. As a result, almost all of the exhaust gas is transferred to the turbine 4.
is directly guided to the soot filter 5. In this way, excessive cooling of the exhaust gas due to expansion within the turbine 4 is prevented. In addition, in order to obtain a sufficiently high exhaust gas temperature for regeneration of the soot filter even in a low load range, the through-flow cross-sectional area of the supercharged air pipe 9 is adjusted by adjusting the throttle valve 10 below the first threshold value function 24. The process temperature is increased by additionally narrowing the air flow rate, i.e. by reducing the amount of suction air. The lower the load Pme of the internal combustion engine, the narrower the flow cross-sectional area of the supercharged air pipe 9 becomes. The second threshold value function 24 is located below the first threshold value function 24 and is related to the engine speed relative to the load of the internal combustion engine.
Below the threshold function 25, the throttle valve lO is kept at its minimum opening. This minimum opening means the throttle valve opening that allows the internal combustion engine to run without any hindrance and at the same time ensures a sufficiently high exhaust gas temperature for the regeneration of the soot filter 5.

The control of the throttle valve 10 in the range 26 between the first threshold value function 24 and the second threshold value function 25 is based on the boost pressure/target value/characteristic diagram stored in the electronic control unit 19. will be carried out. In other words, throttle valve 1
0 is adjusted in this range 26 to an opening corresponding to the target value for the pressure (supercharging pressure) in the supercharging air pipe 9 found from the characteristic diagram at the actual rotation speed n of the internal combustion engine 1 and the actual load Pme. be done. In this case, this target value is determined so that the exhaust gas temperature required for regeneration of the soot filter 5 can be quickly obtained.

On the upper side of the first threshold value function 24, the throttle valve lO
is maintained at an opening that allows the total cross-sectional area of the supercharged air pipe 9 to be freely opened. At the same time, the control of the bypass valve 7 also controls the exhaust gas temperature required for the regeneration of the soot filter 5 even in this operating range 28 (range from the first threshold value function 24 to the full load curve 27 of the supercharged internal combustion engine). It is done so that it can be obtained promptly. That is, this means that from the first threshold numerical aperture 24 onwards, as the load increases, the flow cross-sectional area of the bypass pipe 6 becomes further narrowed. In this range 28 , that is, from the average load range to the full load curve 27 , as in the case of controlling the throttle valve 10 in the range 26 , the opening degree of the bypass valve 7 is determined by the supercharging stored in the electronic control unit 19 . Pressure/target value. Determined from the characteristic diagram. In the figure, 29 is a full load curve of a non-supercharged internal combustion engine.

In order to increase the exhaust gas temperature and to also reduce the nitrogen oxides contained in the exhaust gas, additional exhaust gas recirculation takes place in the low load range below the average load range up to the average speed. .

In the diagram 23 of FIG. 2, exhaust gas recirculation takes place in the region below the limit curve 30. In that case, the exhaust gas recirculation range 31 is within the "throttling range". In order to precisely adjust or control the exact exhaust gas recirculation rate despite the fact that the pressure difference within the exhaust gas recirculation range 31 often fluctuates for all operating conditions of the internal combustion engine, first the actual operating point (
A target value for the intake air mass flow rate is determined from the stored air mass flow rate, target value, and characteristic diagram for the load, rotational speed). To the setpoint value determined in this way, the value now measured by the air quantity detector 15 (see FIG. 1) is adjusted, in particular by a corresponding opening and closing action of the exhaust gas recirculation valve 12.

The larger the cross-sectional area of the exhaust gas recirculation line 11, the greater the air mass flow through the suction line 13 and the charge air line 9.

In addition to or instead of throttling the suction air, it is also conceivable in a further embodiment of the invention to heat the suction air in order to increase the process temperature below the first threshold numerical aperture 24.

Possible embodiments for this purpose are shown in dash-dotted lines in FIG.

That is, upstream of the air filter 14 arranged before the compressor 8, the suction pipe 13 is connected to the first suction pipe section 3.
2 and a second suction piping section 33. Its first suction pipe section 32 guides unheated air. The second suction pipe section 33 intersects an exhaust gas heat exchanger 34 arranged downstream of the soot filter 5 and thereby guides the heated air. A flapper-shaped mixing valve 35 is arranged at the branch point, the degree of opening of which determines the mixing temperature of the intake air flowing into the compression 1118 through the intake pipe 13. This mixing valve 35 can likewise be controlled by the electronic control unit 19 via a control line 36 .

The mixing valve 35 can be controlled steplessly between the terminal opening degrees of 37.40 on both sides. By controlling the mixing valve 35 accordingly in all load ranges between full load 23 and no load.

The temperature of the intake air flowing into the compressor 8 is adjusted to a setpoint value that is related to the operating point stored in the electronic control unit 19 in a characteristic diagram. The measurement of the actual value takes place here with a temperature detector 38 arranged in the suction line 13 , which is connected via a measured value line 39 to the electronic control unit 19 . By suitably mixing the two suction air streams, the temperature of the total exhaust gas stream fed to the soot filter 5 is therefore quickly brought to the value required for its regeneration due to the intentionally elevated process temperature. . The additional process temperature increase below the first threshold value 24 does not have to be carried out exclusively by throttling the suction air or only by heating the suction air. In other embodiments of the invention, these methods can of course also be employed in parallel and synchronized manner.

[Brief explanation of drawings]

FIG. 1 is a piping system diagram for supercharging air and exhaust gas of an internal combustion engine in which the method according to the present invention has been implemented, and FIG. 2 is a characteristic curve diagram in the method according to the present invention. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Exhaust gas turbocharger 4... Turbine 5... Soot filter 6... Bypass piping 7... Bypass valve 8... Compressor 9. ...Supercharged air pipe 10...Throttle valve 13...Suction pipe 19...Electronic control unit 24...First threshold value opening 32...First suction pipe portion 33... Second suction piping portion 35...mixing valve

Claims (1)

[Claims] 1. A particulate filter disposed in the exhaust gas piping of a supercharged internal combustion engine downstream of its exhaust gas turbocharger, the temperature of the exhaust gas reaching this particulate filter is related to an operating parameter. 1. A method for regenerating the internal combustion engine (1) by boosting the internal combustion engine, in which at least a part of the main exhaust gas exiting the internal combustion engine bypasses the turbine of the exhaust gas turbocharger and is guided directly to the particulate filter. ), almost all of the mainstream exhaust gas bypasses the turbine (4) of the exhaust gas turbocharger (2) and passes through the particle filter (5).
, in which case by simultaneously throttling and/or heating the suction air stream, the exhaust gas temperature is maintained at the value necessary for regeneration of the particle filter (5), ranging from the average load range to the full load range. Upstream of the turbine (4) of the exhaust gas turbocharger (2), an exhaust gas partial flow is branched from the main exhaust gas supplied thereto and directly led to the particle filter (5), and this exhaust gas partial flow is is arranged in the exhaust gas pipe of a supercharged internal combustion engine, characterized in that the temperature of the total exhaust gas stream fed to the particle filter (5) is controlled so as to quickly reach the value necessary for its regeneration. How to regenerate a particulate filter. 2. The method as claimed in claim 1, characterized in that exhaust gas recirculation is additionally carried out in a low load range below the average load range up to the average rotational speed of the internal combustion engine (1). 3. A bypass pipe is branched from the exhaust gas pipe upstream of the turbine of the exhaust gas turbocharger, and this bypass pipe opens into the exhaust gas pipe between the turbine and the particle filter, and the through-flow cross-sectional area of the bypass pipe is the first Claim: 1. An electronic control unit is provided which is controllable by a valve arrangement of the internal combustion engine and generates a first regulation value signal for actuating the first valve arrangement as a function of the load and rotational speed of the internal combustion engine. 1
2. A device for carrying out the method according to claim 2, wherein the first adjustment value signal is generated in conjunction with a measured value signal that corresponds to the actual value of the boost pressure, and the first adjustment value signal is generated in conjunction with a measured value signal corresponding to the actual value of the boost pressure, and the boost air line (
9) can be controlled by a second valve arrangement (10) arranged downstream of the compressor (8) of the exhaust gas turbocharger (2), the first regulation value signal Valve device (7
), the through-flow cross-sectional area of the bypass pipe (6) is maximum below the first threshold value function (24) related to the rotation speed with respect to the load of the internal combustion engine, and the first threshold value function (24) On the upper side, control is performed so that the boost pressure is narrowed as the load increases according to the boost pressure, target value, and characteristic diagram, and the electronic control unit (19) controls the boost pressure in relation to the load, rotation speed, and boost pressure of the internal combustion engine. 2, the second adjustment value signal controls the second valve device (10), and the through-flow cross-sectional area of the supercharged air pipe (9) is determined by the first threshold value function (24).
A device characterized in that the device is controlled so that it is maximum on the upper side and narrowed on the lower side. 4. A second threshold function (25) in which the flow cross-sectional area of the supercharged air pipe (9) is related to the rotation speed relative to the load of the internal combustion engine located below the first threshold function (24). is minimum below the first threshold function (24) and the second
In the range (26) between the threshold function (25) of 4. Device according to claim 3, characterized in that the flow cross-section of the pipe is continuously adapted. 5. A bypass pipe is branched from the exhaust gas pipe upstream of the turbine of the exhaust gas turbocharger, and this bypass pipe opens into the exhaust gas pipe between the turbine and the particle filter, and the through-flow cross-sectional area of the bypass pipe is the first Claim: 1. An electronic control unit is provided which is controllable by a valve arrangement of the internal combustion engine and generates a first regulation value signal for actuating the first valve arrangement as a function of the load and rotational speed of the internal combustion engine. 1
or 2, in which the suction pipe (13) upstream of the compressor (8) of the exhaust gas turbocharger (2) comprises a first suction pipe section ( 32) and a second suction pipe section (33) for guiding heated air, a mixing device (35) is disposed at the branch point, and the first adjustment value signal is connected to the first adjustment value signal.
The valve device (7) is arranged such that the through-flow cross-sectional area of the bypass pipe (6) is maximum below the first threshold value function (24) related to the rotational speed with respect to the load of the internal combustion engine, and The upper side of the value function (24) is controlled to be narrowed as the load increases according to the boost pressure, target value, and characteristic diagram, and the electronic control unit (19) adjusts the internal combustion engine's load, rotation speed, and overload. A second regulation value signal is generated as a function of the charge pressure, which second regulation value signal causes the mixing device (35) to adjust the temperature of the intake air entering the compressor so that the The temperature of the total exhaust gas stream fed to the particle filter (5) is controlled to correspond to a setpoint value associated with the operating point stored in the electronic control unit (19) in a characteristic diagram. is determined so that it quickly reaches a value necessary for its reproduction. 6. Device according to claim 5, characterized in that the second suction pipe section (33) is led through an exhaust gas heat exchanger (34). 7. The exhaust gas recirculation pipe (11) branches from the exhaust gas pipe (3) on the upstream side of the turbine (4), and this recirculation pipe (11) branches off from the exhaust gas pipe (3).
1) opens into the supercharged air pipe (9) downstream of the compressor (8), an exhaust gas recirculation valve (12) is disposed in the path of the exhaust gas recirculation pipe (11), and the electronic control unit (19) generates a further regulation value signal in dependence on the measured value signal corresponding to the intake air mass flow introduced therein, which regulation value signal causes the exhaust gas recirculation valve (12) to
12) is controlled to be in the open position below the first threshold function (24) below the average rotational speed of the internal combustion engine (1). The device described in. 8. The opening degree of the exhaust gas recirculation valve (12) is determined from the intake air mass flow rate, target value, and characteristic diagram stored digitally and electronically in the fixed memory of the electronic control unit (19). 8. The apparatus according to claim 7.