DE102011051476A1 - AFTERTREATMENT PROCEDURE - Google Patents

Abstract

An exhaust aftertreatment method includes the steps of: determining whether a driving condition requires an RHU logic process to rapidly raise a temperature of an exhaust gas flowing through an exhaust passage (130); Detecting an ON / OFF signal that executes or ends the RHU logic process; Determining whether an injection signal is enabled to perform the RHU logic process; Detecting an error status of one or more components to execute the RHU logic process; and detecting the temperature of the exhaust gas during execution of the RHU logic process and comparing the detected temperature with a modeled value. Accordingly, a malfunction of the RHU logic process is avoided in good time, so that the RHU logic process is carried out safely and a malfunction is reported to the driver via an error signal, which improves the on-board diagnostic function.

Description

The present application claims the priority of Korean Patent Application No. 10-2010-0120936 , filed on Nov. 30, 2010, the entire contents of which are incorporated herein by this reference.

The present invention relates to an exhaust aftertreatment method that uses a rapid heat-up (RHU) logic process to rapidly raise a temperature of the exhaust gas for activating the catalyst that reduces the pollutants contained in the exhaust gas.

In a conventional exhaust gas purifying apparatus, a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF) and a selective catalytic reduction (SCR) unit are successively arranged along an exhaust passage in a predetermined order.

Engine exhaust passes through the DOC, DPF and SCR unit in turn, eliminating any pollutants it contains.

Specifically, this means that the DPF captures particulates (PM) in the exhaust gas, the DOC oxidizes the carbon monoxide and hydrocarbons in the exhaust to carbon dioxide, and the SCR unit reduces the nitrogen oxides in the exhaust to nitrogen.

The exhaust gas temperature on an upstream side of the SCR unit must be above 200 ° C for the nitrogen oxides to actively react with the reductant. However, the SCR unit is located in a rear end portion of the exhaust passage, so that a comparatively long time is required until the exhaust gas temperature at the input side of the SCR unit reaches 200 ° C.

Accordingly, the nitrogen oxides contained in the exhaust gas are hardly reduced before leaving the outside until the exhaust gas temperature at one input side of the SCR unit reaches 200 ° C.

Therefore, a rapid heat-up (RHU) logic process for rapidly raising the exhaust gas temperature has been applied stepwise to quickly heat the catalyst, and it is necessary to detect a driving condition for execution of the RHU logic process and to make a mistake thereof detect.

The information disclosed herein in connection with the prior art of the invention is merely for the better understanding of the general state of the art and should not be taken as an acknowledgment or any form of indication that this information represents a prior art well known to those skilled in the art.

The present invention has been made in an effort to provide an exhaust aftertreatment method that has advantages in the implementation of the RHU logic process for quickly raising a temperature of the exhaust gas and has an on-board diagnostic function that indicates whether an RHU logic process is normal expires or not.

An exhaust aftertreatment method includes the steps of determining whether a driving condition is an RHU logic process for rapidly raising a temperature of an exhaust gas flowing through an exhaust gas passage (FIG. 130 ) flows, needed; Detecting an ON / OFF signal that executes or terminates the RHU logic process; Determining if an injection signal is enabled to execute the RHU logic process; Detecting an error status of one or more components to execute the RHU logic process; and detecting the temperature of the exhaust gas during execution of the RHU logic process and comparing the detected temperature with a modeled value.

Preferably, the exhaust aftertreatment method further comprises the step of outputting an error signal when the detected temperature that has been raised by the RHU logic process deviates from the modeled value.

Preferably, the exhaust aftertreatment method further comprises the steps of accumulating the error signal and storing the accumulated value and activating an RHU logic warning lamp when the accumulated value exceeds a predetermined value.

Preferably, the running state for executing the RHU logic process must satisfy an entry condition for entering the RHU logic process, wherein the entry condition is determined based on an atmospheric pressure, a vehicle speed, an engine speed, an intake air temperature, a coolant temperature, a gear stage, and a fuel injection quantity.

Preferably, when the entry condition for entry into the RHU logic process is satisfied, an after-injection amount for the execution of the RHU logic process is determined based on the engine speed and the fuel injection amount and the fuel injection amount is increased.

Preferably, in the step of detecting an error status of one or more components, one of the components includes an injector Fuel injection and a temperature sensor for detecting the temperature of the exhaust gas.

Preferably, a diesel oxidation catalyst that oxidizes pollutants contained in the exhaust gas, a diesel particulate filter that filters particulates contained in the exhaust gas, a metering module that injects a reducing agent into the exhaust gas flowing through the exhaust gas passage, and an SCR unit ( Selective catalytic reduction), which uses the injected from the metering module reducing agent to reduce nitrogen oxides contained in the exhaust or oxidize, arranged sequentially in the exhaust gas line.

Preferably, a temperature sensor detects temperatures downstream of the engine, upstream of the diesel oxidation catalyst, upstream of the diesel particulate filter and upstream of the SCR unit.

As described above, according to the exhaust gas aftertreatment method according to the present invention, a malfunction of the RHU logic process is prevented at an early stage to surely realize the RHU logic and inform the driver of a malfunction by means of an error signal, so that the on-board diagnostic function is improved.

The methods and apparatus of the present invention have further features and advantages, as will become apparent in detail from the appended and the following detailed descriptions, which are incorporated herein and together serve to explain certain principles of the present invention.

1 FIG. 10 is a schematic illustration of an exemplary exhaust aftertreatment system according to the present invention. FIG.

2 FIG. 10 is a schematic flow diagram of an exemplary exhaust aftertreatment process according to the present invention. FIG.

3 FIG. 10 is a detailed flowchart showing an exemplary exhaust aftertreatment method according to the present invention. FIG.

4 FIG. 12 is a diagram showing a temperature of the exhaust gas and a diagnosis function thereof in a state in which an exemplary RHU logic process according to the present invention is executed. FIG.

Reference will now be made in detail to the various embodiments of the present invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the embodiments, it is to be understood that the present description is not intended to limit the invention to those exemplary embodiments. On the other hand, it is intended that the invention not only cover the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that fall within the spirit and scope of the invention as defined in the appended claims.

1 FIG. 3 is a schematic illustration of an exhaust aftertreatment system according to various embodiments of the present invention. FIG.

As in 1 As shown, an exhaust aftertreatment system includes an engine 100 , an injector 110 , a control unit (ECU) 120 , an exhaust gas line 130 , a diesel oxidation catalyst 140 , a diesel particulate filter 150 , a dosing module 160 , a mixer 170 , a selective catalytic reduction unit 180 and a temperature sensor having one or more sensors, such. B. T3, T4, T5, T6 and / or T7.

The injector 110 is at the engine 100 arranged and injected fuel into a cylinder to perform a rapid heat-up (RHU) post-injection.

The exhaust of the engine 100 happens in turn the diesel oxidation catalyst 140 the exhaust route 130 , the diesel particulate filter 150 , the mixer 170 and the SCR unit 180 before being led outside via a silencer.

The temperature sensor T4-T7 detects a temperature of the exhaust gas entering the diesel oxidation catalyst 140 flows, a temperature of the exhaust gas that enters the diesel particulate filter 150 flows, and a temperature of the exhaust gas that enters the SCR unit 180 flows.

The control unit 120 uses a driving condition of the engine 100 and the exhaust gas temperature in the exhaust line 130 in determining whether or not to execute an RHU logic process, and if the entry condition for the execution of the RHU logic is met, are via the injector 110 a normal injection and a post-injection carried out.

Furthermore, the controller uses 120 a driving state or an operating point of the engine 100 and the exhaust gas temperature in the exhaust line 130 to stop the RHU logic process or prevent the RHU logic process from starting.

2 FIG. 3 is a schematic flow diagram of various embodiments of the present invention. FIG Invention, and 3 FIG. 10 is a detailed flowchart depicting an exemplary exhaust after-treatment process according to various embodiments of the present invention. FIG.

As in 2 is shown, in a step S200, it is determined whether a monitored condition is an RHU function, e.g. As the RHU logic process, needed or not. Here it is determined whether a driving condition justifies the RHU logic process.

Furthermore, the monitoring of an RHU function itself may be understood as a condition that justifies the execution of the RHU logic process.

In particular, in the block 1 in 3 , the controller detects an atmospheric pressure, a vehicle speed, an engine speed, an intake air temperature, a coolant temperature, a gear, a fuel injection amount and an exhaust gas temperature T6 or T7, and decides whether or not to perform the RHU function, and monitors the state that the RHU function is executed.

In a step S210 of 2 determines if the RHU function is ON or OFF. In a step S220, it is determined whether or not an injection signal for executing the RHU function is activated.

The injection signal includes an operating signal provided by the controller 120 is communicated to the injector 110 to operate, so that a post-injection is carried out.

In step S230, an error of the components for the execution of the RHU logic is detected. As in the block 4 of the 3 shown are the injector 110 and the temperature sensor T3 to T7 used to perform a rapid heating (RHU). When the injector 110 or the temperature sensors T3 to T7 malfunction or fail, the controller generates an error signal from the rapid heating components (RHU).

In a step S240, a temperature of the exhaust gas during the rapid heating (RHU) is detected, and the detected temperature is compared with a modeled temperature. It is determined whether the temperature of the exhaust gas is within a predetermined temperature range.

If the RHU function is ended in a step S250, the monitoring ends with the output of the result. As in blocks 5 and 6 out 3 is shown, the RHU function is evaluated by detecting the temperatures of the exhaust gas by means of the temperature sensor.

In particular, if the exhaust gas temperature during monitoring exceeds a predetermined temperature range, the generated error signal is counted and stored their number.

If the number exceeds a predetermined or modeled value, it is determined that the RHU logic is abnormally operated so that a warning lamp, e.g. B. a malfunction warning lamp is activated.

4 FIG. 10 is a diagram showing a temperature of the exhaust gas and a diagnosis function thereof in a state in which an exemplary RHU logic process according to various embodiments of the present invention is executed.

As in 4 2, the horizontal coordinate axis is a time axis, and the vertical axis shows a temperature of the exhaust gas entering the SCR unit 180 into flows.

As shown, an area is the RHU model temperature 400 set by code or map value. A course 410 the temperature of the exhaust gas entering the SCR unit 180 is formed during an ON condition of the RHU. Furthermore, a course 420 the temperature of the exhaust gas during an OFF condition of the RHU formed.

In addition, a temperature profile is modeled by means of the driving state or operating point of the engine and the RHU 430 the exhaust gas shown. When a temperature 410 the modeled temperature 430 and exceeds the predetermined temperature range, becomes an error signal 440 generated.

The control unit 120 counts the error signals and stores the counted number. If this number exceeds a predetermined or modeled value, a warning light is activated.

For purposes of explanation and detail of the appended claims, terms such as "upper," "lower," "inner," and "outer" are used to describe the features of the exemplary embodiments with respect to the features illustrated in the figures.

The foregoing descriptions of the specific exemplary embodiments of the present invention are for the purpose of illustration and description. They are not to be construed as exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations are possible in light of the above teachings. The exemplary embodiments have been selected and described to reflect certain principles of the invention To explain the invention and its practical application and thus to enable the skilled person to manufacture and use of the various embodiments of the present invention and of its numerous alternatives and modifications. It is intended that the scope of the invention be defined by the appended claims and their equivalents.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• KR 10-2010-0120936 [0001]

Claims (8)

An exhaust aftertreatment method, comprising the steps of: determining whether a driving condition is an RHU logic process for rapidly raising a temperature of an exhaust gas flowing through an exhaust gas passage (FIG. 130 ) flows, needed; Detecting an ON / OFF signal that executes or terminates the RHU logic process; Determining if an injection signal is enabled to execute the RHU logic process; Detecting an error status of one or more components to execute the RHU logic process; and detecting the temperature of the exhaust gas during execution of the RHU logic process and comparing the detected temperature with a modeled value. The exhaust aftertreatment process of claim 1, further comprising the step of: Outputting an error signal if the detected temperature raised by the RHU logic process deviates from the modeled value. Exhaust gas aftertreatment method according to claim 2, further comprising the steps of: Accumulating the error signal; and Storing the accumulated value and activating an RHU logic warning lamp if the accumulated value exceeds a predetermined value. 2. The exhaust gas aftertreatment method according to claim 1, wherein the running state for executing the RHU logic process has to meet an entry condition for entering the RHU logic process, wherein the entry condition is determined based on an atmospheric pressure, a vehicle speed, an engine speed, an intake air temperature, a coolant temperature , a gear stage and a fuel injection amount. The exhaust aftertreatment method according to claim 4, wherein, when the entry condition for entering the RHU logic process is satisfied, a post-injection amount for execution of the RHU logic process is determined based on the engine speed and the fuel injection amount and the fuel injection amount is increased. Exhaust gas aftertreatment method according to claim 1, wherein in the step of detecting an error status of one or more components, one of the components has an injector ( 110 ) for fuel injection and a temperature sensor (T3, T4, T5, T6, T7) for detecting the temperature of the exhaust gas. An exhaust aftertreatment process according to claim 1, wherein a diesel oxidation catalyst ( 140 ) which oxidizes pollutants contained in the exhaust gas; a diesel particulate filter ( 150 ) which filters particles contained in the exhaust gas; a dosing module ( 160 ), which is a reducing agent in the exhaust gas passing through the exhaust line ( 130 ) flows, injects; and a SCR unit (Selective Catalytic Reduction) ( 180 ), that of the dosing module ( 160 ) injected in order to reduce or oxidize nitrogen oxides contained in the exhaust gas, successively in the exhaust gas line ( 130 ) are arranged. Exhaust gas aftertreatment method according to claim 7, wherein a temperature sensor (T3, T4, T5, T6, T7) downstream temperatures of the engine ( 100 ), upstream of the diesel oxidation catalyst ( 140 ), upstream of the diesel particulate filter ( 150 ) and upstream of the SCR unit ( 180 ) detected.

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