AT501336B1 - Assembly and series of steps to determine the operating efficiency of an automotive exhaust selective catalyst reduction unit - Google Patents

Assembly and series of steps to determine the operating efficiency of an automotive exhaust selective catalyst reduction unit Download PDF

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Publication number
AT501336B1
AT501336B1 AT1772005A AT1772005A AT501336B1 AT 501336 B1 AT501336 B1 AT 501336B1 AT 1772005 A AT1772005 A AT 1772005A AT 1772005 A AT1772005 A AT 1772005A AT 501336 B1 AT501336 B1 AT 501336B1
Authority
AT
Austria
Prior art keywords
exhaust gas
exhaust
nox
diagnostic
throttle
Prior art date
Application number
AT1772005A
Other languages
German (de)
Other versions
AT501336A1 (en
Inventor
Ingo Dr Allmer
Original Assignee
Avl List Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Avl List Gmbh filed Critical Avl List Gmbh
Priority to AT1772005A priority Critical patent/AT501336B1/en
Priority claimed from DE112006000054T external-priority patent/DE112006000054A5/en
Publication of AT501336A1 publication Critical patent/AT501336A1/en
Application granted granted Critical
Publication of AT501336B1 publication Critical patent/AT501336B1/en

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Classifications

    • Y02T10/24
    • Y02T10/47

Abstract

An automotive exhaust system has a diagnostic unit determining the condition of the selective catalyst reduction unit. In a series of stages, in the first step the diagnostic system defines the threshold NOx concentration under one or more defined operating conditions. In subsequent steps the unit then shifts the engine's operational mode into an operational diagnostic condition in which more NOx is produced than in the normal mode. The dosing device is subsequently regulated to adjust the quantity of reduction agent corresponding to the change in NOx emissions. The concentration of NOx is measured downstream from the post-treatment station and compared with the threshold value. A decision is then made as to the absence of error in operation of the exhaust gas treatment system based on a comparison of the measured concentration of NOx with the threshold vale, followed by termination of the diagnostic stage. also claimed is a commensurate automotive diagnostic assembly.

Description

2 AT 501 336 B1

The invention relates to a method for operating an internal combustion engine.

From DE 102 61 877 A1 a method for operating an internal combustion engine with a particle filter is known, wherein a arranged in the exhaust system of the internal combustion engine particulate filter 5 is regenerated as needed. Here, in the operation of the internal combustion engine, a λ-value of an air-fuel ratio between a value <1 and a value> 1 is changed periodically over a predetermined period of time such that a temperature of the particulate filter is raised to a value by exhaust heating is increased, in which a regeneration of the particulate filter takes place. 10

Furthermore, JP 2003-161145 A discloses an exhaust aftertreatment device with a NOx catalyst in the exhaust line and a throttle valve arranged downstream thereof. EP 1 321 642 A1 shows an exhaust gas control device for a diesel filter, which can be regenerated by increasing the temperature in the exhaust gas stream, wherein in the exhaust line a variable throttle device upstream of the particulate filter and downstream of a turbine of an exhaust gas turbocharger, and downstream of a branch of an exhaust gas recirculation line from the exhaust line is. 20

It is also known to increase the air mass flow in front of the inlet collector to increase the temperature in the particulate filter. This reduces the air flow and excess air. With lower excess air, the same amount of fuel is burned with less air, which raises the temperature of the products of combustion. The disadvantage is that a large reduction in volume is accompanied by 25 throttles in front of the intake manifold, which prolongs the regeneration period of the particulate filter.

The object of the invention is to avoid these disadvantages and to propose a method for the regeneration of a post-treatment device with a short regeneration period. 30

According to the invention this is achieved in that the exhaust gas flow in operating phases in which the operating temperature of the internal combustion engine and / or at least one exhaust aftertreatment device is below a defined operating temperature, or in operating phases in which a regeneration of an exhaust aftertreatment device is performed 35, throttled.

The throttle device can be arranged downstream of the turbine of an exhaust gas turbocharger. 40 For the regeneration of the exhaust gas aftertreatment device, the internal combustion engine switches to regeneration operation. For this purpose, the temperature after the exhaust gas turbine must be increased, e.g. to about 620 ° C, with a certain oxygen content in the exhaust gas, for example, 6%, should not fall below. By the throttle device in the outlet of the exhaust gas back pressure is increased. This leads to an increase in the charge exchange work, whereby there is only a slight change in the air mass flow. So that the torque can be maintained, the injected fuel amount is increased, which leads to the reduction of the ratio of air to fuel and thus to a further increase in temperature. By compared to a throttle device in the intake manifold larger total mass flow, the regeneration period of the exhaust aftertreatment device can be significantly shortened who-50. In addition, the influence on the pressure curve in the cylinder is lower than with a throttle valve in the intake system, which results in a lower noise change when switching.

It is particularly advantageous if the injected fuel quantity is increased during the at least partial closing of the throttle input in order to avoid a power loss.

L 3 AT 501 336 B1

The throttle device arranged downstream of the turbine also has the advantage that the response of the internal combustion engine in transient mode is improved. For an acceleration process while the throttle device is opened, which increases the pressure ratio directly to the turbine and thus the transfer from the turbine to the compressor-5 ne performance.

By increasing the exhaust gas temperature in this system, an acceleration of the warm-up of the internal combustion engine is possible, especially the operation of exhaust aftertreatment devices, such as. Catalysts improved. This makes it possible to reduce emissions in the driving cycle.

In a further embodiment of the invention can be provided that the variable throttle device is arranged downstream of a branch of an exhaust gas recirculation line from the exhaust system. As a result, in the normal operation by the throttle device, the exhaust gas recirculation rate 15 can also be controlled and even increased more than with a throttle device in the intake system. Thus, the throttle in the intake system can be completely replaced by a throttle in the exhaust system.

The invention will be explained in more detail below with reference to FIG. 20

The FIGURE shows an internal combustion engine 1 with a plurality of cylinders 2, 3, 4, with an inlet branch 5 and an outlet branch 6. A charge air filter 7 and a charge air cooler 8 are arranged in the inlet branch. Exhaust system 6 and inlet system 5 are connected to each other via an exhaust gas recirculation line 9, which branches off upstream of the turbine 10 of an exhaust gas turbocharger 11 25 from the outlet strand 6. With reference numeral 12, the compressor of the exhaust gas turbocharger 11 is designated.

Downstream of the turbine 10, an exhaust gas aftertreatment device 13, for example a particle filter, is arranged. Between the turbine 10 and the exhaust aftertreatment device 30 13, a throttle device 14 formed by a flap is provided in the exhaust line 6.

To carry out the regeneration of the exhaust gas aftertreatment device 13, the internal combustion engine 1 is switched to regeneration mode. For this purpose, the temperature after the turbine 10, for example, must be increased to 620 ° C, with a certain oxygen content in the exhaust gas of about 6% may not be exceeded and where further the engine torque 35 should remain unchanged. To achieve this, the throttle device 14 is at least partially closed in the exhaust line 6. This causes the exhaust back pressure to increase, and thus the charge cycle work of the engine 1 is increased. In comparison to a throttling device indicated by reference numeral 15 in the intake manifold 5, only a small change in the air mass flow occurs. In order to keep the torque constant, the amount of fuel injected is increased, which leads to a reduction in the ratio of air to fuel and thus to an increase in temperature. Due to the greater mass flow compared to a throttle device in the intake manifold, the regeneration period of the exhaust aftertreatment device 13 can be significantly shortened. In addition, the influence on the pressure curve in the cylinders 2, 3, 4 is lower than with a throttle device 15 in the intake system 5, which results in a lower noise change when switching between normal engine operation and regeneration operation.

Another advantageous effect relates to the transient behavior of the internal combustion engine 1. For an acceleration process, the throttle device 14 is opened, which increases the Druckverhält 50 nis directly to the turbine 10 and thus increases the power transmitted from the turbine 10 to the compressor 12. With the throttle device 14 in the exhaust system 6 and the exhaust gas recirculation rate in normal operation - compared with a throttle device 15 in the intake system 5 - can be increased. 55

Claims (3)

1. A method for operating an internal combustion engine, characterized in that the exhaust gas flow in operating phases in which the operating temperature of the internal combustion engine and / or at least one exhaust gas aftertreatment device is below a defined operating temperature, or in operating phases, in which a regeneration of an exhaust gas aftertreatment device is performed is throttled.
2. The method of claim 1 for the regeneration of an exhaust gas in an internal combustion engine io arranged exhaust aftertreatment device, in particular a Partikelfil age, wherein a temperature increase of the exhaust gas, a regeneration phase of the particulate filter is initiated, characterized in that arranged to increase the temperature of the exhaust gas, preferably upstream of the exhaust aftertreatment device Throttle device is at least partially closed, and that the internal combustion engine 15 is controlled so that no power loss occurs during the regeneration phase.
3. The method according to claim 2, characterized in that during the at least partially closing of the throttle device, the injected fuel amount is increased to 2o to avoid a power loss. For this purpose 1 sheet of drawings 25 30 35 40 45 50 55
AT1772005A 2005-02-03 2005-02-03 Assembly and series of steps to determine the operating efficiency of an automotive exhaust selective catalyst reduction unit AT501336B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT1772005A AT501336B1 (en) 2005-02-03 2005-02-03 Assembly and series of steps to determine the operating efficiency of an automotive exhaust selective catalyst reduction unit

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AT1772005A AT501336B1 (en) 2005-02-03 2005-02-03 Assembly and series of steps to determine the operating efficiency of an automotive exhaust selective catalyst reduction unit
DE112006000054T DE112006000054A5 (en) 2005-02-03 2006-01-19 Method for the diagnosis of an exhaust aftertreatment system
US11/792,398 US8286417B2 (en) 2005-02-03 2006-01-19 Diagnosis method for an exhaust gas post-treatment system
PCT/AT2006/000029 WO2006081598A2 (en) 2005-02-03 2006-01-19 Diagnosis method for an exhaust gas post-treatment system

Publications (2)

Publication Number Publication Date
AT501336A1 AT501336A1 (en) 2006-08-15
AT501336B1 true AT501336B1 (en) 2007-02-15

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AT1772005A AT501336B1 (en) 2005-02-03 2005-02-03 Assembly and series of steps to determine the operating efficiency of an automotive exhaust selective catalyst reduction unit

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AT (1) AT501336B1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003161145A (en) * 2001-09-12 2003-06-06 Mitsubishi Motors Corp Exhaust emission control device
EP1321642A1 (en) * 2001-12-12 2003-06-25 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Exhaust emission control device
DE10261877A1 (en) * 2002-11-22 2004-06-03 Volkswagen Ag Method for operating an internal combustion engine with a particle filter
US20040159098A1 (en) * 2003-02-19 2004-08-19 Xinqun Gui Strategy employing exhaust back-pressure for burning soot trapped by a diesel particulate filter
WO2004106703A1 (en) * 2003-05-28 2004-12-09 Isuzu Motors Limited Exhaust gas cleaning system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003161145A (en) * 2001-09-12 2003-06-06 Mitsubishi Motors Corp Exhaust emission control device
EP1321642A1 (en) * 2001-12-12 2003-06-25 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Exhaust emission control device
DE10261877A1 (en) * 2002-11-22 2004-06-03 Volkswagen Ag Method for operating an internal combustion engine with a particle filter
US20040159098A1 (en) * 2003-02-19 2004-08-19 Xinqun Gui Strategy employing exhaust back-pressure for burning soot trapped by a diesel particulate filter
WO2004106703A1 (en) * 2003-05-28 2004-12-09 Isuzu Motors Limited Exhaust gas cleaning system

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Publication number Publication date
AT501336A1 (en) 2006-08-15

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