HUT73253A - Method and apparatus for controlled regeneration of diesel soot filter - Google Patents

Abstract

For controlled regeneration of a diesel engine diesel filter in the process according to the invention, the diesel torsion filter in the exhaust gas tract is divided into several parallel coupled sections, at least one of which, depending on the temperature behind the diesel rim filter, is partially or completely sealed. If the maximum allowable temperature after the diesel filter is exceeded, the diesel diesel filter section concerned will be partially or even completely eliminated from the exhaust gas flow, so that the amount of exhaust gas passing through the other sections increases in such a way that regeneration is again controlled or even interrupted. Figure 1

Description

PROCEDURE AND DEVICE DIESEL CHECK

the regeneration

The present invention relates to a process for the controlled regeneration of a diesel soot filter, wherein the exhaust gas stream is suppressed by the diesel soot filter, depending on the exhaust gas temperature, after the diesel soot filter.

The invention further relates to a device for the controlled regeneration of a diesel soot filter, wherein a throttle controlled by the exhaust gas temperature is provided after the diesel soot filter.

It is known that porous wall diesel sootblowers allow gaseous portions of the exhaust gas to pass through, but prevent the passage of solid particles, which are formed mainly by the coagulation and precipitation of carbon molecules and heavy hydrocarbon particles.

The soot particles that accumulate in the diesel soot filter, which grow in size during operation, can be destroyed during the regeneration of the diesel soot filter by thermal (incineration) catalytic or similar processes.

In the case of a diesel engine operating by thermal regeneration, for example, in a vehicle equipped with a thermal regenerator that is automatically triggered under stochastic conditions, the combustion rate of the particles accumulated in the diesel soot filter can increase uncontrollably. This can lead to an unacceptable increase in temperature resulting in partial or total fusion or failure of the diesel soot filter.

In order to avoid uncontrolled combustion, measurement of the exhaust gas temperature behind the diesel soot filter is recommended in DE-38 06 219 A1, where a predetermined maximum allowable temperature is exceeded.

81712-5941A SR-Sch • ·

-2 With the help of an electronic unit, valves are operated in front of and behind the diesel soot filter so that all the exhaust gas is drained away bypassing the diesel soot filter. As a result, the diesel soot filter is temporarily completely removed from the exhaust gas stream.

If the bypass is only a small percentage of the total engine life, a silencing device must be used to attenuate the noises generated during bypass operation. In addition, it is ecologically undesirable, even for a short period of time, to release contaminated exhaust gases into the environment unfiltered, as will be the case with the bypass operation.

Also known from CH 663 253 A is a particle filter which is arranged in particular on an exhaust gas tract of an internal combustion engine filled with exhaust gas, with two parallel coupled sections, namely a well-insulated high temperature channel and a low temperature channel with low and, at high engine loads, both channels allow exhaust gas to escape by properly adjusting a control plate. Thus, with frequent particle combustion, it is achieved that the exhaust gas charger connected after the exhaust gas path is always rapidly communicated to the exhaust gas at a satisfactory temperature so that the so-called turbocharger opening can be avoided when the accelerator pedal is depressed. However, the controlled incineration of particles deposited in the sewers is not achieved by the measures contained in the Swiss patent.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for regenerating diesel soot filters used in diesel engines to provide effective protection against damage or failure of the diesel soot filter simply and avoiding the adverse conditions associated with operating the bypass.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for the controlled regeneration of a diesel soot filter, wherein the exhaust gas stream is a · ·. · ♦

By means of a soot filter, depending on the exhaust gas temperature, the diesel soot filter is suppressed and the diesel soot filter is divided into a plurality of parallel sections, at least one of which passes through the exhaust gas depending on the exhaust gas temperature, completely or after the diesel soot.

In order to accomplish this method, the present invention provides a device for the controlled regeneration of a diesel soot filter device comprising a soot choke controlled after the diesel soot filter, the diesel soot filter being divided into at least two parallel diesel soot sections, the throttle (s) being disposed after the diesel soot, controlled by the temperature of the exhaust gas.

According to the invention, the diesel soot filter is divided into several parallel sections connected to the exhaust gas stream, of which at least one can be completely or partially switched off from the exhaust gas stream depending on the temperature of the exhaust gas formed at the outlet of the respective section.

As long as the reaction in the insulated section is reduced or interrupted, the throughput through the non-bypassed remaining section or sections of the diesel soot filter increases. Thus, the reaction rate of thermal regeneration in these remaining stages is reduced. Should the remaining non-deactivated section of the diesel soot filter also reach the maximum allowable temperature, this section will also be deactivated from the exhaust gas stream. This process according to the invention continues until the passage through the last remaining portion of the diesel soot filter increases to such an extent that the reaction initiated is interrupted or canceled.

thus, simple means can provide effective protection of the diesel soot filter from uncontrolled combustion of the deposited particles.

-4because it is damaged or damaged. This solution prevents the leakage of untreated gases caused by the bypass plant and eliminates the need for expensive silencing equipment.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the following exemplary embodiments. The attached drawings show

Figure 1 is a four-cylinder diesel engine with a connected diesel soot filter of the invention in the exhaust gas tract,

Figure 2 is a graph of the reaction rate of regeneration versus passage of a diesel soot filter, a

Figure 3 is a six-cylinder engine with a modified diesel soot filter of the invention, a

4-6. Figs. 4 to 5 show further modified embodiments of the diesel carbon black filters of the present invention.

Fig. 1 illustrates a four-cylinder diesel engine 1 with diesel soot filters 2, 4 and 6 installed in the exhaust gas path 3 and wherein no bypass for the diesel soot filter is provided. These three diesel soot filters are mounted parallel to the exhaust gas path 3 and have a common inlet extension 5 from which separate inlet manifolds 5a, 5b and 5c extend into their respective diesel soot filters 2, 4 and 6, and The outflow manifolds 7c, which start from the diesel soot filters 2, 4 and 6, are introduced into a common outflow extension 7.

Inlet pipe nozzles 5a, 5b and 5c each have a throttle member 10, 12 and 14, i.e. the same number of throttle members as there are diesel soot filters. The outlet nozzles 7a, 7b and 7c are provided with thermocouples 9, 11 and 13 for the separate measurement of the exhaust gas temperature. The output signals of the thermocouples 9, 11 and 13 are fed to an electronic unit 100 controlling the throttling organs. The throttle bodies 2, 4 and 6 are in the embodiment shown as a throttle flap.

- 5 Diesel soot filters 2, 4 and 6 are regenerated by periodically burning the deposited soot particles by increasing the temperature during operation or by continuing the exhaust gas. In the case of a desired regeneration, the throttling organs 10, 12 and 14 are actuated simultaneously by the electronic unit 100.

During regeneration, to prevent uncontrolled combustion, the throttle means 10, 12, or 14 of the diesel soot filter 2, 4 or 6 are sealed and thereby shut off from the exhaust gas stream, beyond which the measured exhaust gas temperature exceeds a predetermined temperature. Complete or partial closure of the respective inlet manifolds 5a, 5b or 5c to an ON / OFF signal or an analog actuator signal from the electronic unit 100 is provided. The electronic unit 100 receives the output signal of the thermocouples 9, 11 and 13 as an input signal.

At a constant exhaust gas temperature, the reaction rate of the onset of the soot accumulated in the diesel soot filter depends on the amount of permeation.

Fig. 2 is a graph showing the reaction rate w of the combustion versus the mass passage m. If the temperature behind the diesel particulate filter 2, which is filled with particle amount G, exceeds the maximum allowable exhaust gas temperature, this filter 2 is partially or completely blocked by actuation of the associated throttle 10 with the result that the mass flow rate is reduced to mi. In this case, the exhaust gas passes through the 4 and 6 diesel soot filters. Accordingly, the mass permeability m through the diesel soot filters 4 and 6 rises above m ₂ . This means that the reaction rate aw is reduced in all filters as shown in the graph in Figure 2. If the exhaust gas temperature exceeds the maximum allowable after an additional diesel soot filter, for example after the 4 diesel soot filter, this diesel soot filter will be similar to the one used for the 2 diesel soot filters • ··· · ·· «

-6 has been described, continued or even terminated. This then leads to an increase in the mass permeability m at the diesel soot filter 6, whereby the reaction rate is reduced to a value such that any reaction initiated is interrupted or canceled.

The system will continue to operate normally after the exhaust gas temperature is below the maximum allowable value after each of the 2, 4 and 6 diesel soot filters.

Assuming perfect protection in the diesel soot filter against unchecked combustion of the deposited amount of particulate, the last diesel soot filter will cause the diesel engine to idle or cancel the reaction even when idling.

In this way, the volume and number of diesel soot strokes for a given diesel engine can be predetermined.

Figure 3 illustrates a six-cylinder diesel engine with diesel soot injectors 4, 16, 18, 20 and 22. Again, each diesel soot filter has a choke 24, 26, 28 and 30 at its respective inlets not shown, and a thermocouple 32, 34, 36 and 38 at its respective not shown outlets.

One turn off of diesel soot from the exhaust gas stream one by one.

by means of an electronic unit (not shown), in a similar manner as in the embodiment illustrated in Figure 1, in which at least one diesel soot filter remains in operation in the final stage.

The throttling means may be in the form of a throttle or a valve.

Figure 4 illustrates two diesel soot filters with inputs 50 and 51, which consist of a single unit. Through the inlet formed without the throttle 51, the exhaust gas is introduced into the diesel soot filter section 52. The exhaust gas flowing through the inlet 50 enters section 57. This inlet 50 is provided with a throttle 40. The output behind both sections 52 and 57 is the following: •, · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

-7 cross-sections are provided with thermocouples T1 and T2 in their centerline.

Uncontrolled combustion protection is achieved by actuating the throttle member 40 in the inlet 50 whether or not one of the thermocouples T1 or T2 registers an inadmissible temperature. Due to the tubular inlet 51, the section 52 is so small that the mass flow through it at idle is so great that the combustion of the soot deposited is delayed or even interrupted.

Unlike the embodiments illustrated in Figures 1 and 3, the embodiment shown in Figure 4 (and the embodiments illustrated in Figures 5 and 6) have only one throttle member 40, which reduces the number of moving and thus more easily defective structural members. , and the construction becomes simpler. The absence of a throttle in section 52 surprisingly has no effect on the regeneration forced by the throttling of the exhaust gas.

Regeneration by particle combustion is achieved by closing the single throttle 40. As a result, the back pressure of the exhaust gas is increased and accordingly the temperature of both filters of the diesel soot filter can be achieved.

Uncontrolled burn protection is effective in most cases at low or medium speeds and at low loads. In this case, the deterioration of the driving characteristics due to the increased back pressure due to the reduced exit surface is not detected by the driver because he can achieve the desired performance by actuating the accelerator pedal. In the event of protection in the high speed or high power range, the protection process can be interrupted by a Kick-Down switch.

As is known, in this operating phase the protection against uncontrolled combustion is taken over by the cooling effect of the exhaust gas. In an analogous way, an ongoing sequel can be interrupted if the driver needs full performance.

• ····

Figure 5 illustrates a diesel soot filter having two sections, namely a larger section 67 and a smaller section 62, with no throttle arrangement at the inlets 60 and 61 of the sections. A single shut-off member is formed by a thermostat 64 disposed in a common outlet duct between the two sections 62 and 67 and exhaust gas flowing therefrom from the sections 62 and 67. When the thermostat expands, it closes the outlet opening 63 of the larger section 67 at a predetermined exhaust gas temperature. In this embodiment, the temperature control at the outlet of the diesel soot filter becomes unnecessary, and thus an electronic control unit is also unnecessary, since the thermostat 64 automatically takes over the protection of the two sections 62 and 67 from uncontrolled combustion when the exhaust gas temperature reaches a predetermined temperature.

The thermostat 64 in this embodiment consists of a closed rib tube which expands axially as a result of internal pressure. The thermostat is filled with a suitably selected gas, such as sodium, which evaporates when the temperature is reached, thereby causing a rapid increase in internal pressure. As a result, thermostat 64 is elastically elongated and closes outlet 63.

Figure 6 shows a variant of the embodiment illustrated in Figure 5, wherein a diesel soot filter 71 comprises a smaller section 72 and a larger section 77 arranged in a monolithic unit. Exhaust gas enters these sections 72 and 77 through a common inlet 70. Like the embodiment illustrated in Figure 5, a thermostat formed as an axially expanding rib tube at the outlet 73 of the larger section 77 is arranged to automatically close the outlet opening of the outlet 73 when a predetermined temperature is reached.

Claims (10)

Claims A method for the controlled regeneration of a diesel engine diesel soot filter, wherein the exhaust gas stream is suppressed by the diesel soot filter, depending on the exhaust gas temperature, after the diesel soot filter, characterized in that the diesel soot filter is depending on the temperature of the exhaust gas, it is suppressed or completely closed after the diesel sootblower. Apparatus for the controlled regeneration of a diesel soot filter, wherein after the diesel soot is arranged a throttle controlled by the exhaust gas temperature, characterized in that the diesel soot filter comprises at least two parallel diesel soot filters (2, 4, 6; 16, 18, 20, 22; 62, 67; 72, 77), at least one of which can be partially or wholly blocked by a throttle (10, 12, 14; 24, 26, 28, 30; 40; 64; 74) and which temperature of the exhaust gas is controlled by a diesel sootblower. Device according to claim 2, characterized in that each diesel soot filter section (2, 4, 6; 16, 18, 20, 22) has separate throttle members (10, 12, 14; 24, 26, 28, 30). ) are provided in their respective inlet manifolds (5a, 5b, 5c) and in the outlet manifolds (7a, 7b, 7c) with separate temperature measuring devices, preferably thermocouples (9, 11, 13; 32, 34, 36, 38;) They have. Apparatus according to claim 2, characterized in that one of the at least two separate sections (52, 57; 62, 67; 72, 77) provides an unobstructed flow of exhaust gas and the other (52; 62; 72). and the section (57; 67; 77) is partially or completely closed by a throttle (40; 64; 74), depending on the temperature at the outlet. 5. A device according to claim 3 or 4, characterized in that the device comprises a corresponding section of a diesel soot filter. - an electronic unit (100) for operating one or more chokes (10, 12, 14; 24, 26, 28, 30; 40) at a temperature exceeding a predetermined temperature in the outlet nozzle (7a, 7b, 7c; 53). is assigned. Device according to claim 4 or 5, characterized in that the temperature sensing thermocouples (Τ1, T2) are arranged at the output of the sections (52, 57) and regardless of which of the thermocouples (Τ1, T2) is detected. a temperature greater than that permitted at the actuation of the throttle member (40) disposed at the inlet of the larger section (57) by a control unit, preferably an electronic unit (100). Apparatus according to claim 4, characterized in that when a predetermined temperature of the exhaust gas is exceeded, a thermostat (64, 74) configured as an automatically actuating shut-off member is disposed at the outlet of the larger section (67, 77). Device according to Claim 7, characterized in that the thermostat (64, 74) formed as a closing device is a rib tube, which is filled with an evaporating material, in particular sodium, at a temperature above a predetermined temperature. Device according to Claim 7 or 8, characterized in that the two sections (72, 77) are part of a monolithic unit. 10. A device according to any one of the preceding claims, characterized in that the device is formed without a drain pipe bypassing the diesel soot filters.