DE10355664A1 - Exhaust emission reduction system includes particulate filter within exhaust stream, heat exchanger to adjust temperature of diesel exhaust stream and catalytic absorber of nitrogen oxides within temperature adjusted diesel exhaust stream - Google Patents

Abstract

An exhaust emission reduction system includes a diesel particulate filter (DPF) (20) contained within the exhaust stream, a heat exchanger (40) to adjust the temperature of the diesel exhaust stream; at least one catalytic absorber (60) of nitrogen oxides (NOx) within the temperature adjusted diesel exhaust stream; a heat source (30) capable of heating the exhaust stream and a computing device. The computing device monitors the temperature of the exhaust stream entering the DPF and the NOx absorber. Independent claims are included for the following: (a) controlling the exhaust emission reduction system for reducing exhaust stream emissions produced by a diesel engine; and (b) a computing device for controlling the system for reducing exhaust stream emissions produced by the diesel engine.

Description

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates Exhaust emission reduction systems for removing suspended matter and nitrogen oxides (NOx) from the exhaust gas streams of diesel engines, and in particular it concerns the improvement of the efficiency of emission reduction systems with a non-selective catalytic reduction component.

The combustion gases of diesel engines contain carbon dioxide, carbon monoxide, unburned hydrocarbons, NOx and suspended solids. Environmental regulations, such as the emission standards EURO 4 (2005) and EURO 5 (2008) as well as 2004 and U.S. Pat. 2007, increasingly calling for an emissions control, to the diesel exhaust gas values for Lower NOx and suspended matter more and more. Limit the regulations increasing the amount of NOx that occurs during a given drive cycle, such as the FTP cycle (Federal Test Procedure) in the United States or the United States MVEG cycle (MVEG = Mobile Vehicle Emission Group) in Europe.

One of the well known in the art options For removing NOx from the exhaust gas of diesel engines is the catalytic Reduction. In a catalytic reduction process becomes substantially the exhaust gas is passed over a catalyst bed in the presence of a reducing gas, to convert the oxidized nitrogen into elemental nitrogen. Two types of catalytic reduction are the non-selective catalytic Reduction (NSCR) and Selective Catalytic Reduction (SCR). This invention relates to emission reduction systems with NSCR.

Roth et al., U.S. Patent No. 6,446,430, discloses a method and apparatus for reducing transient and stationary NOx emissions in the exhaust gases of a vehicle, which by a with Diesel fuel working internal combustion engine is driven, containing a downstream of the engine reduction catalyst. Of the Catalyst comprises a reduction catalyst and a system for Injecting diesel fuel as a hydrocarbon (HC) reducing agent into the exhaust upstream from the catalyst. Roth recognizes that transient engine conditions are the Increase the temperature of the exhaust gas which in turn increases the temperature of the catalyst up to the Increase the point is exceeded where the temperature window in which it comes to NOx conversion can be.

The conversion efficiency of some NOx catalysts is temperature dependent. The effective operating temperature range is generally intermediate 250 ° and 450 ° C (degrees Celsius), depending on the catalyst, and over 750 ° to 800 ° C, the catalyst can be damaged. When operating the diesel engine with high load, the Exhaust gas temperatures slightly exceed these ranges.

Diesel Particulate Filter (DPF) for removal of suspended matter from the exhaust stream of a diesel engine have become as extremely effective when removing carbon black proved. The most widely used diesel soot filter is the wall flow filter, which The diesel exhaust filters by moving the suspended matter on the porous walls of the filter body holds. Cutler et al., US Pat. No. 6,464,744, discloses a porous diesel exhaust particulate filter made of ceramic. The ceramic filter includes several at its end with a Plug closed honeycomb structures that together contain the suspended matter withhold in diesel exhaust and burn. As suspended solids accumulate, the pressure drop above the Filter finally until a back pressure against the engine is created and the filter must be regenerated. During the regeneration process the filter becomes warmed up to the burning of coal to get started. Normally the regeneration takes place under controlled conditions Conditions of engine management, causing a slow combustion is set in motion and a few minutes lasts, during which time the temperature in the filter of about 400 ° to 600 ° C on a maximum of about 800 ° to 1000 ° C increases.

In the systems currently available there is the problem of effective combustion of diesel particulate matter at temperatures of the exhaust streams of 300 ° C or lower. Although the temperature of the diesel exhaust stream may exceed 500 ° C, but it may also be lower, e.g. 300 ° C or below, and, as above noted, the filters are not particularly effective for burning retained Suspended solids at such low temperatures.

As noted above, this requires Regeneration of the diesel particulate filter (DPF) usually exhaust gas temperatures of at least 600 ° C, although some filters regenerate continuously as they catalytic additives contain the soot ignition temperatures between 350 ° and 450 ° C provide. However, low load diesel engines can produce exhaust, whose temperature is too low to filter even in catalytic diesel particulate filters To burn suspended matter.

While the above systems have been found to be advantageous in reducing certain diesel exhaust emissions, it has also been found advantageous to operate such systems at temperatures that maximize their efficiency. In particular, diesel particulate filters operate extremely efficiently at a temperature above a certain threshold, often at a temperature higher than the typical temperatures of the die Selective gas flows, and NOx catalysts work extremely effective in a temperature window, which is often below the typical exhaust gas flow temperatures.

SUMMARY THE INVENTION

In the present invention goes it's about heat management an integrated emission reduction system for the removal of Suspended matter and nitrogen oxides (NOx) from the exhaust gas streams of Diesel engines. The integrated invention Emission Reduction System may include a Diesel Particulate Filter (DPF), a heat source for adjusting the temperature of the exhaust gas flow entering the DPF, at least one catalytic NOx absorber, a heat exchanger for adjusting the Temperature of the NOx absorber incoming exhaust stream and a computing device for monitoring the temperature of the entering into the DPF and the NOx absorber Exhaust gas flow and for controlling the operation of the heat exchanger and the heat source include, whereby the efficiency of the DPF regeneration and the NOx absorber is improved.

An exemplary embodiment of the emission reduction system receives an exhaust gas flow from one a vehicle driving diesel engine. The exhaust gas flow is through a DPF, a heat exchange system, a NOx absorber system, a Diesel oxidation catalyst (DOC) and a silencer passed. The emission reduction system comprises an electronic control unit (ECU) to monitor and controlling the process of exhaust emission reduction.

The conversion efficiency of NOx catalysts is temperature dependent, and the combustion of suspended matter is also temperature dependent. Therefore it is advantageous if in the different components of the Emission reduction system such as the DPF and the NOx absorber entering exhaust gas stream is adjusted to a temperature that maximizes the efficiency of the system components. In particular It is often beneficial to monitor the temperature of the exhaust stream entering the DPF to increase and the temperature of the exhaust gas stream entering the NOx absorber to increase or decrease to a specific temperature window.

In one form comprises an exhaust emission reduction system for reducing the exhaust emissions produced by a diesel engine a particulate filter contained in the exhaust stream, a heat exchanger for adjusting the temperature of the diesel exhaust stream, at least a catalytic NOx absorber in the temperature controlled diesel exhaust stream and a heat source, which heat the exhaust stream can.

In another form includes a Method for controlling an exhaust emission reduction system for Reducing exhaust emissions generated by a diesel engine Steps of monitoring and controlling the temperature of the entering into a particulate filter Exhaust gas flow, which improves the functioning of the particulate filter will, and monitoring and controlling the temperature of the catalytic NOx absorber entering exhaust gas flow, whereby the functioning of the NOx absorber is improved.

There is another form a computer apparatus for controlling an exhaust emission reduction system for reducing the exhaust emissions produced by a diesel engine; the emission reduction system comprises a particle filter, a catalytic NOx absorber system and a heat transfer system that heat the Supply exhaust stream or heat can remove from the exhaust stream; includes the computing device a microprocessor ("processor") and software that monitor the temperature of the exhaust gas stream entering the particulate filter can, the heat transfer system for adjusting the temperature of the exhaust stream can control to improve the functioning of the particulate filter, the temperature can monitor the exhaust gas entering the absorber and the heat transfer system can control to adjust the temperature of the exhaust stream to to improve the functioning of the absorber.

The above and other features and Objects of this invention as well as the way and how these tasks solved become more apparent, and the invention itself becomes better understandable, with reference to the following description of embodiments of the invention in conjunction with the attached Drawings; show in it:

1 an assembly view of an integrated emission reduction system according to the invention, which is provided in a vehicle powered by a diesel engine;

2 a plan view of the integrated emission reduction system of 1 ;

3 a block diagram of a control system for controlling the integrated emission reduction system of 1 ;

4 a process flow diagram of the integrated emission reduction system of 1 ; and

5A - 5D Software flowcharts of the control device of 3 ,

Corresponding reference characters designate corresponding parts throughout the several views. While the drawings illustrate embodiments of the present invention, the drawings are not necessarily to scale, and certain features may be exaggerated in order to better illustrate and explain the present invention. The herein set forth Games illustrate embodiments of the invention in several forms, and these examples are not to be construed as limiting the scope of the invention in any way.

DESCRIPTION THE PRESENT INVENTION

The embodiments disclosed below should not be exhaustive or the invention to those detailed in the following Description of the disclosed limited precise forms. The embodiments are rather chosen and described that other professionals can use their teaching.

This in 1 shown vehicle 12 is powered by a diesel engine and includes an integrated emission reduction system 10 for removing particulate matter and nitrogen oxides (NOx) from the diesel engine exhaust stream 17 , as in 2 shown. According to 1 and 2 includes the emission reduction system 10 Total diesel particulate filter (DPF) 20 , a heat source 30 , a heat exchange system 40 , a NOx absorber system 60 , a Diesel Oxidation Catalyst (DOC) 80 , a silencer 90 , an exhaust pipe 96 and a tax system 100 , as in 3 shown. The inventive method and the control system 100 for thermal management of the integrated emission reduction system according to the invention 10 provides for emission reduction systems with a non-selective catalytic reduction (NSCR) component such as the NOx absorber system 60 a higher efficiency ready.

Regarding 2 includes the DPF 20 a filter structure 22 for retaining and burning suspended matter such as coal in diesel exhaust. The filter structure 22 is well known in the art and may be, for example, a porous ceramic that forms a plurality of plugged honeycomb structures at its end that can effectively remove carbon percipitation from diesel engine exhaust. In a continuously regenerating catalytic DPF, the filter structure comprises 22 a catalyst. The DPF 20 For example, in the exemplary embodiment, it may include a filter made by Corning Inc. of Corning, New York, such as that which is the subject of U.S. Patent No. 6,464,744.

The heat source 30 can increase the temperature of the exhaust gas from diesel engines. In particular, the heat source should be 30 be able to raise the exhaust gas temperature to the ignition temperature of carbon black which may be in the range of at least 600 ° to 650 ° C or at least 300 to 350 ° C when using a catalyst-added DPF. The target value S1, hereinafter defined as a temperature sufficient to burn coal soot, is in the range of 600 ° to 650 ° C. The heat source 30 For example, in the exemplary embodiment, it includes a diesel fuel powered burner such as available from ArvinMeritor, of Columbus, Indiana. Such a heat source 30 includes a fuel regulator 32 for controlling the heat source 30 supplied diesel fuel, a fuel atomizing air regulator 34 for controlling the atomization of the diesel fuel for combustion and an air blower regulator 36 for controlling the air flow for the combustion of the diesel fuel by the heat source 30 ,

The heat exchange system 40 provides a temperature setting, generally cooling, of the diesel engine exhaust. The heat exchange system 40 includes an exchange path 42 and a bypass 44 , which are connected as parallel lines for a stream of diesel engine exhaust. The exchange route 42 contains the heat exchanger 50 that the heat exchange structure 56 comprising a flow of coolant supplied through the coolant control valve 51 regulated and via the coolant inlet 52 and the coolant outlet 54 provided. The coolant may be from an existing engine cooling system, provided additional cooling capability is available, for example in a light vehicle, or from a separate independent cooling system, for example a heavy vehicle where the cooling reserve may be limited.

The bypass route 44 includes a heat exchange bypass valve, which in the exemplary embodiment may be a high temperature exhaust control valve, such as Part No. 2010499, manufactured by ArvinMeritor, located in Columbus, Indiana. The flow of engine exhaust through the heat exchanger 50 depends on the valve 46 in the bypass 44 provided flow resistance. If, for example, the valve 46 the bypass 44 closes, the flow of engine exhaust through the heat exchanger 50 amplified, and when the valve 46 is open and the flow of exhaust gas through the bypass path 44 allowed, the flow of engine exhaust through the heat exchanger 50 reduced. An exemplary heat exchanger 50 is part no. 1202496, manufactured by Behr America, Inc. located in Troy, Michigan.

The NOx absorber system 60 comprises at least one catalytic NOx absorber 62a , The NOx absorber 62a provides a non-selective catalytic reduction (NSCR) that converts engine exhaust NOx into nitrogen. The NOx absorber 62a can be a catalyst 64a include, for example, a potassium or barium-containing catalyst on a ceramic or metal substrate. For regenerating the NOx absorber 62a When it reaches its capacity, hydrocarbons (HCV) in the form of diesel fuel can pass through a reducing agent injection system 70a in the NOx absorber 62a is injected, to desorb and regenerate the catalyst 64a be used. The NOx absorber system 60 may include additional NOx absorbers that are associated with the absorber 62a can be connected in series or in parallel.

This in 2 shown NOx absorber system 60 The exemplary embodiment includes first and second NOx absorbers 62a and 62b , by the engine exhaust under the control of the first and second Absorbengelventils 68a and 68b optionally supplied. The first absorber valve 68a regulates the flow of engine exhaust through the first absorber inlet path 66a that with the first NOx absorber 62a connected is. The second absorber valve 68b regulates the flow of engine exhaust in the second absorber input path 66b that with the second NOx absorber 62b connected is. The first and the second exhaust path 76a and 76b , each with the first and second NOx absorbers 62a and 62b are connected to each other to the parallel circuit of the NOx absorber system 60 to complete.

The first and second injection systems used in the exemplary embodiment 70a and 70b can be of the type available from ArvinMeritor. The exemplary first and second NOx absorbers 62a and 62b may be, for example, NOx Absorbers made by Engelhard Corporation of Iselin, New Jersey and Johnson Matthey of London, England. The first and second absorber valves 68a and 68b For example, in the exemplary embodiment, high temperature exhaust control valves made by ArvinMeritor may be.

The Diesel Oxidation Catalyst (DOC) 80 reduces unburned hydrocarbons (HC) and carbon monoxide (CO) present in diesel exhaust. The DOC 80 catalyzes the oxidation of unburned hydrocarbons and CO. Such devices are well known in the art. A suitable example is available from ArvinMeritor.

The silencer 90 and the exhaust pipe 96 Provide noise reduction of the engine exhaust and direct the exhausted engine exhaust stream 98 ,

According to 3 includes the tax system 100 for thermal management and regeneration of the integrated emission reduction system 10 a control device 101 , The control device 101 is a processor-based control system including a processor including, for example, RAM (Random Access Memory), FLASH animation technology, EEPROM (Electrically Erasable and Programmable Read Only Memory), Integrated Controller Area Network (CAN), etc., and software can who the in 5A - 5D shown process control to various aspects of the emission reduction system 10 to monitor and control. Such an exemplary control device 101 can be implemented as part of an engine control unit (ECU).

In the present invention, the control device obtains 101 Input signal information from the engine speed sensor 15 , the turbocharger speed sensor 16 , the DPF inlet pressure sensor 24 , the DPF inlet temperature sensor 25 , the DPF outlet pressure sensor 26 , the DPF outlet temperature sensor 27 , the air blower control 36 , the NOx inlet temperature sensor 56 , the NOx inlet sensor 72 and the NOx outlet sensor 74 , Upon receiving all of the above input signal information, the controller processes 101 the received data and generates output signals for controlling the fuel regulator 32 , the fuel sprayer 34 , the air blower regulator 36 , the heat exchanger valve 46 , the coolant valve 51 , the valve 68a of the NOx absorber A, the valve 68b of the NOx absorber B, the reducing agent injection valve A. 70a and the reducing agent injection valve B 70b ,

Overall, with respect to 2 and 4 For example, in the exemplary embodiment, the engine exhaust stream 17 from the diesel engine to the integrated emission reduction system 10 via the engine exhaust connection 18 fed. The engine exhaust connection 18 is with the DPF 20 connected. The temperature T1 and the pressure P1 of the DPF 20 entering exhaust gas stream 17 be through the control device 101 using the DPF inlet pressure sensor 24 and the DPF inlet temperature sensor 25 supervised. The control device 101 can change the temperature of the DPF 20 entering exhaust gas stream 17 by controlling the heat source 30 regulate. In particular, the control device 101 the fuel regulator 32 , the fuel atomizing air regulator 34 and the combustion air blower regulator 36 control the temperature T1 of the DPF 20 entering exhaust gas stream 17 to increase to an optimum temperature range for the operation of the DPF.

The temperature T2 and the pressure P2 of the DPF 20 exiting exhaust stream 17 is through the control device 101 using the DPF outlet pressure sensor 26 and the DPF outlet temperature sensor 27 supervised.

The one through the heat exchange system 40 flowing exhaust gas flow 17 and the resulting temperature change of the exhaust stream 17 be through the control device 101 using the heat exchanger valve 46 and the coolant valve 51 controlled. In addition, the cooling of the through the heat exchange system 40 flowing exhaust gas stream 17 through the flow of the exhaust stream 17 through the heat exchanger 50 regulated, a function of the heat exchanger bypass valve 46 that the bypass 44 wholly or partly opens or closes and the exhaust stream 17 through the heat exchanger 50 presses, and also a function of the through the coolant valve 51 regulated flow of coolant through the heat exchanger 50 ,

The temperature T3 of the heat exchange system 40 exiting and into the NOx Ab sorbersystem 60 entering exhaust gas stream 17 is through the control device 101 using the NOx inlet temperature sensor 56 supervised. As required, the temperature of the exhaust gas flow through the heat exchange system 40 lowered from the temperature of the exhaust gas flow of the particulate filter in the direction of an optimized temperature for the NOx absorption.

The first and the second absorber valve 68a and 68b control the flow of the exhaust stream 17 through the NOx absorber system 60 such that one of the first and second NOx absorbers 62a respectively. 62b is in operation and the exhaust gas flow 17 while the other of the first and second NOx absorbers 62a and 62b is being regenerated and by the first or second reductant injection system 70a or 70b Reducing agent gets fed to the capacity of the catalyst 64a or 64b restore.

So that the control device 101 the efficiency and remaining capacity of the first and second NOx absorbers 62a and 62b can monitor the NOx absorber system 60 a NOx inlet sensor 72 for monitoring the NOx content N1 at an inlet of the NOx absorber system 60 and a NOx exhaust sensor 74 for monitoring the NOx content N2 at an outlet of the NOx absorber system 60 include. The control device 101 can then the NOx content of the NOx absorber system 60 entering and exiting exhaust stream 17 monitor and determine when the currently operating NOx absorber 62a or 62b must be regenerated. However, NOx sensors are currently prohibitive for most commercially viable diesel engine applications; the control device 101 can therefore switch between the NOx absorbers 62a and 62b based on other engine operating parameters and predicted NOx values based on the elapsed time of engine operation or a combination of these and other factors.

The one from the NOx absorber system 60 exiting exhaust gas flow 17 is used to remove unburned HC and CO to the DOC 80 fed. Finally, the exhaust gas stream flows 17 through the noise-reducing silencer 90 and the exhaust pipe 96 and leaves the integrated emission reduction system 10 as ejected exhaust stream 98 ,

The thermal management of the integrated emission reduction system 10 provides improved removal efficiency of NOx and particulate matter from the exhaust stream 17 a diesel engine ready. In particular, a heat transfer system, which in the exemplary embodiment is a heat source 30 and a heat exchange system 40 includes, by the control device 101 controlled to the temperature of the DPF 20 entering exhaust gas stream 17 adjust and adjust the temperature of the NOx absorber system 60 entering exhaust gas stream 17 to adjust to a temperature window, reducing the efficiency of the operation of the DPF 20 and the NOx absorber system 60 is increased.

The DPF 20 may retain and burn suspended matter, generally coal soot. At low engine load, the exhaust gas flow 17 have a temperature of 300 ° C or below. In general, the available diesel particulate filters are not particularly effective for burning particulate matter at such low temperatures. The monitoring of the DPF inlet temperature T1 by the sensor 25 allows the control device 101 , the temperature of the DPF 20 entering exhaust gas stream 17 by controlling the heat source 30 to increase. The heat source 30 Can the temperatures of the exhaust stream 17 increase to a range of more efficient regeneration of a continuously regenerating catalytic diesel particulate filter 20 allowed. For example, the temperature of the DPF 20 entering exhaust gas stream 17 increased to over 270 ° C, preferably more than 300 ° C, more preferably to more than 350 ° C. The setpoint S2, defined below as the effective minimum operating temperature for the DPF 20 , is in the range of 300 ° to 350 ° C.

In addition, the heat source 30 be able to regenerate a non-continuously regenerating non-catalytic DPF 20 to enable. The control device 101 monitors the DPF inlet pressure P1 and the DPF outlet pressure P2 using the inlet pressure sensor 24 and the outlet pressure sensor 26 to determine if the DPF 20 due to an excessive amount of retained particulate matter in the DPF 20 must be regenerated. An excessive amount of suspended particulate matter in the DPF 20 can cause excessive back pressure in the exhaust stream 17 and lead against the diesel engine. An excessive amount of retained particulate matter is released from the DPF 20 removed by a regeneration cycle in which the temperature in the DPF 20 is increased, so that retained suspended matter is burned. This is achieved, for example, by increasing the temperature of the exhaust gas stream 17 periodically using the heat source 30 to a temperature above 600 ° C, and preferably above 650 ° C, but below a temperature that exceeds the filter structure 22 in the DPF 20 damaged, for example less than 1000 ° C and more preferably less than 900 ° C.

The NOx absorber system 60 provides increased efficiency when the temperature T3 of the first or second NOx absorber 62a or 62b entering exhaust gas stream 17 within a temperature window that is the particular absorber coating used 64a and 64b provides an increased efficiency. For example, in a potassium-containing absorber, the Temperature of the in the first and the second NOx absorber 62a and 62b entering exhaust gas stream 17 greater than 250 ° C, preferably greater than 300 ° C, and more preferably greater than 360 ° C, but less than 450 ° C, preferably less than 435 ° C, and more preferably less than 420 ° C. The setpoint S3, defined below as the effective operating temperature window for the NOx absorbers 62a and 62b , is in the range of 360 ° to 420 ° C.

If another absorber coating 64a and 64b is provided, for example, barium, a slightly different temperature window is preferred according to the operating efficiency of the catalyst. At low engine load or immediately after starting, the exhaust gas flow may 17 thus have a temperature below the preferred temperature window, and thus the control device 101 the heat source 30 in that the inlet temperature T3 of the NOx absorber is increased to a value within the preferred temperature window.

In addition, it is at normal engine load or because of a greater warming of the exhaust stream 17 through the heat source 30 for greater efficiency of the DPF 20 likely that the temperature T3 of the NOx absorber system 60 entering exhaust gas stream 17 will be higher than the preferred temperature window. The control device 101 Therefore, the cooling of the exhaust gas flow 17 Control by passing through the bypass path 44 flowing exhaust gas flow 17 using the valve 46 completely or partially blocks, and can provide increased coolant flow by the coolant control valve 56 that the heat exchanger 50 Coolant feeds, wholly or partially opens and thus the temperature T3 of the NOx absorber system 60 entering exhaust gas stream 17 reduced.

The first and second NOx absorbers 62a and 62b can develop a reduced capacity because absorbed substances (attributable to the sulfur content of the diesel fuel) with the NOx around attachment sites on the absorber coating 64a and 64b compete. Restoring the capacity of the first and second NOx absorbers 62a and 62b is possible by adjusting the temperature of the first and second NOx absorbers 62a and 62b guided exhaust gas flow 17 is sufficiently increased to release the adsorbed to the sulfur content of the diesel fuel absorbed substances. For example, at a periodically performed regeneration, the control device 101 the heat source 30 to control that the temperature T3 of the first and second NOx absorbers 62a and 62b entering exhaust gas stream 17 is increased to more than 500 ° C, preferably more than 550 ° C and more preferably to more than 600 ° C. Setpoint S4, defined below as one of the release of absorbed substances from the attachment sites on the absorber coating 64a and 64b sufficient temperature, is in the range of 550 ° to 600 ° C.

The control device 101 is also capable of the exhaust gas flow 17 optionally to the first NOx absorber 62a or to the second NOx absorber 62b to steer. For example, the control device 101 the second absorber valve 68b close, so that the exhaust gas flow 17 no longer in the entrance way 66b of the second absorber, and the first absorber valve 68a open so that the exhaust gas flow 17 through the entrance way 66a the first absorber flows. The first NOx absorber 62a is therefore in operation to remove NOx from the exhaust stream 17 to absorb, and the NOx absorber 62b can be regenerated at the same time.

When regenerating, the second injection system 70b To provide hydrocarbon (HC) in the form of diesel fuel, which acts as a reducing agent to the NOx catalyst 74b to desorb and regenerate. After regeneration of the NOx absorber 62b can the control device 101 the first absorber valve 68a close and the second absorber valve 68b open, bringing the NOx absorber 62b is put into operation and analogous to the simultaneous regeneration of the first NOx absorber 62a allowing, the first injection system 70a Hydrocarbon (KW) in the form of diesel fuel can provide.

Switching between the first and second NOx absorbers 62a and 62b for operation and regeneration can by the control device 101 based on the predicted NOx output and the capacity of the first and second NOx absorbers 62a and 62b for given engine operating parameters, based on the elapsed time of the engine and the time elapsed since the last regeneration, a combination of these parameters or the measurement of the actual NOx content N1 at the inlet of the NOx absorber system 60 and the actual NOx content N2 at the outlet of the NOx absorber system 60 be determined. Although the exemplary embodiment is a NOx inlet sensor 72 and a NOx outlet sensor 74 for monitoring the actual NOx content N1 and N2 of the exhaust gas flow 17 may include predicted or actual diesel engine operating parameters including engine speed 15 and the turbocharger speed 16 and other parameters related to the NOx content of the exhaust stream 17 additionally or alternatively used to the first and the second NOx absorber 62a and 62b optionally to regenerate.

According to 5A - 5D now contains the control device 101 a processor and software operatively connected to the processor and modules for controlling the emissions reduction system 10 can perform. For the purposes of this invention, a module is part of the software that contains one or more functions. Every function leads a specific task. Each module includes a plurality of conditional instructions, ie instructions that allow the modules to operate differently depending on an input provided by the processor each time they are executed. In 5A - 5D the process control flow is shown when the software is controlled by the control device 101 is performed.

According to 5A the module A 102 is executed when the control device 101 running the software. The module A 102 provides the thermal management process control for regeneration of the DPF 20 and for controlling the temperature of the NOx absorber system 60 entering exhaust gas stream 17 ready. After running module A 102, the conditional statement must 104 (ie if DPF regeneration is necessary). If the processor returns the input TRUE (= "correct"), then the module A is leading 102 the function 110 off to the heat source 30 to set the temperature measured at the DPF inlet temperature T1 to the setpoint S1. After performing the function 110 module A 102 must issue the conditional statement 112 meet (ie whether the inlet temperature T3 of the NOx absorber has the setpoint S3). If the processor returns the input FALSE (= "false"), then the module A 102 performs the function 114 out to the coolant flow valve 51 and the bypass valve 46 of the heat exchanger 40 adjust. After performing the function 114 module A 102 must return the conditional statement 112 (ie, whether the inlet temperature T3 of the NOx absorber has the setpoint S3). As long as the processor receives the input FALSE from the conditional instruction 112 returns the conditional statement 112 and the function 114 repeatedly executed or executed until the inlet temperature T3 of the NOx absorber reaches the setpoint S3 and the processor to the conditional instruction 112 the input value returns TRUE. If the conditional statement 112 the input returns TRUE, then the conditional statement must 116 (ie, whether DPF regeneration is complete) can be accomplished by module A 102. If the processor returns the input FALSE, then the conditional statements must 112 respectively. 116 are satisfied until the processor returns the input TRUE to both. If the processor has the input TRUE on the conditional instruction 116 returns, then the module A 102 performs the function 118 off to the heat source 30 off. After execution of the function 118 module A 102 will start at the conditional instruction 104 run again.

If the processor has the input FALSE on the conditional instruction 104 (ie if the DPF regeneration is necessary) returns, then the conditional statement 130 (ie, whether the NOx inlet temperature T3 has the setpoint S3) are met. If the processor returns the input TRUE, then the module A 102 will be the conditional instruction 104 run again. If the processor returns the input FALSE, then the module B 103 is executed and the conditional instruction 132 (ie, if the NOx inlet temperature T3 is too high) must be met. If the processor returns the input TRUE, then the conditional statement must 134 (ie whether the heat source 30 is turned on) are met by the module B 103. If the processor returns the input TRUE, then the module B 103 performs the function 136 to either reduce the fuel flow or the heat source 30 off. After execution of the function 136 through module B 103, the conditional statement must 132 be met again. If the processor has the input FALSE on the conditional instruction 134 returns, then the module B 103 performs the function 138 out to the coolant flow valve 51 and the bypass valve 46 of the heat exchanger 50 adjust. After execution of the function 138 Module B 103 needs the conditional statement 140 (ie whether the heat exchanger 50 has a coolant flow). If the processor returns the input FALSE, then the module B 103 performs the function 142 off to set off an alarm. The alarm alerts the controller 101 , which then generates a message and / or a correction process, for example, to reduce the engine load conditions and to activate an engine control lamp. If the processor has the input TRUE on the conditional instruction 140 returns, then the module B 103 is executed again and the conditional statement 132 must be fulfilled.

If the processor has the input FALSE on the conditional instruction 132 The module B 103 must return the conditional statement 150 (ie, whether the NOx inlet temperature T3 is too low). If the processor returns the input FALSE, then process control returns to module A 102 from the conditional instruction 104 must be re-executed. If the processor has the input TRUE on the conditional instruction 150 returns, then the conditional statement 152 (ie, whether in the heat exchanger 50 Coolant flows) can be met. If the processor has the input TRUE on the conditional instruction 152 returns, then the module B 103 performs the function 154 to reduce the coolant flow and / or the bypass flow. After module B 103 the function 154 has executed module B 103 from the conditional instruction 132 run again. If the processor has the input FALSE on the conditional instruction 152 returns, module B 103 performs the function 156 off to either the heat source 30 turn on or increase the fuel flow. After execution of the function 156 will module B 103 from the be did instruction 132 run again. Module B 103 is executed until process control returns to module A 102 when the processor sets input FALSE to the conditional instruction 150 returns. Module A 102 is running until the diesel engine exhaust stream 17 ceases.

According to 5B Now, the module C 200 can be executed when the control device 101 running the software. The module C 200 may be executed simultaneously or optionally with other software modules or may be integrated into the module A 102. Module C 200 provides thermal management process control of a minimum temperature for the DPF 20 entering exhaust gas stream 17 ready. After executing module C 200, the conditional statement must 202 whether the inlet temperature T1 of the DPF 20 the setpoint S2 of the minimum temperature has to be met. If the processor returns the input FALSE, then module C 200 performs the function 204 off to the heat source 30 in operation and to regulate the temperature measured at the DPF inlet temperature T1 to the setpoint S2. After execution of the function 204 will module C 200 from the conditional statement 202 run again. If the processor is on the conditional statement 202 When the input returns TRUE, module C 200 returns to the conditional instruction 202 back. Module C 200 can be run until the diesel engine exhaust stream 17 ceases.

According to 5B Module D 300 is executed when the control device 101 running the software. Module D 300 provides a thermal management process control of the desulphurisation of the NOx absorber system 60 ready. Module D 300 may be executed simultaneously or optionally with other software modules or may be integrated into module A 102. If the conditional statement 302 whether a desulphurisation of the NOx absorber system 60 is necessary, returns the input value TRUE, then module D 300 performs the function 304 off to the heat source 30 to put into operation and to control the measured at the NOx absorber inlet temperature T3 to the setpoint S4. After execution of the function 304 the module D 300 needs the conditional statement 306 (ie, whether the NOx inlet temperature T3 has the set value S4). If the processor returns the input FALSE, then the module D 300 performs the function 308 off to the fuel flow of the heat source 30 adjust. After execution of the function 308 The D 300 module must return the conditional statement 306 fulfill. As long as the processor sets the input FALSE to the conditional statement 306 returns the conditional statement 306 and the function 308 is repeatedly executed until the NOx absorber inlet temperature T3 reaches the set value S4 and the processor sets the input value TRUE to the conditional instruction 306 returns. If the conditional statement 306 the input returns TRUE, then the conditional statement must 310 (ie whether the NOx desulphurization is completed) of module D 300 are met. If the processor returns the input FALSE, then the conditional statements must 306 or 310 are satisfied until the processor returns the input TRUE to both. If the processor has the input TRUE on the conditional instruction 310 returns, then module D 300 becomes the conditional instruction 302 run again. Module D 300 can be run until the diesel engine exhaust stream 17 ceases.

According to FIG. SD, the module E 400 can now be executed when the control device 101 running the software. The module E 400 provides a process control for selectively regenerating the NOx absorbers 62a and 62b ready. The software module E 400 may be executed simultaneously or optionally with other software modules, or may be integrated into the software module A 102. Module E 400 performs function 402 to open the valve 68a of the NOx absorber A and the function 404 to close the valve 68b of the NOx absorber B off. After performing the function 404 then has the conditional statement 406 (ie, whether the NOx absorber A 62a needs to be regenerated). When the processor returns input TRUE, then module E 400 sequentially performs function 408 to open the valve 68b of the NOx absorber B, the function 110 for closing the valve 68a of the NOx absorber A and the function 412 for activating the reducing agent injection valve A 70A and the regeneration of the absorber A 62a, respectively. If the processor has the input FALSE on the conditional instruction 406 returns, then the module E 400 repeatedly returns to the conditional instruction 406 until the processor returns the input TRUE. After execution of the function 412 must be the conditional statement 414 (ie whether the regeneration of the NOx absorber A 62a completed). If the processor returns the input value FALSE, then the module E 400 repeatedly performs the function 412 and must have the conditional statement 414 until the regeneration is complete and the processor sets the input TRUE to the conditional instruction; 414 returns. If the conditional statement 414 the input returns TRUE, then the conditional statement must 416 (ie whether the NOx absorber B 62b must be regenerated) are met by the module E 400. If the conditional statement 416 returns the input FALSE, then the conditional statement 416 repeatedly executed until the processor returns the input TRUE. If the processor has the input TRUE on the conditional instruction 416 hin hin returns, then the module E 400 successively performs the function 418 to open the valve 68a of the NOx absorber A, the function 420 to close the valve 68b of NOx absorber B and the function 422 for activating the reducing agent injection valve B 70b or the regeneration of the absorber B 62b out. After the module E 400 the function 422 has executed the conditional statement 424 (ie whether the regeneration of the NOx absorber B 62b completed). If the processor returns the input value FALSE, then the module E 400 repeatedly performs the function 422 and must have the conditional statement 424 fulfill until the regeneration of the NOx absorber 62b is completed. If the processor has the input TRUE on the conditional instruction 424 returns, then the module E 400 from the conditional statement 406 run again.

Although this invention has been described as she would have an exemplary structure, but the present invention further modified within the spirit and scope of this disclosure become. This application is therefore intended to all variations, uses or adaptations of the invention using their general Cover principles. Furthermore, this application is intended to those deviations from the present disclosure, which is within the scope of known or usual Practice in the field to which this invention belongs fall.

Claims (36)

Exhaust emission reduction system for reducing the exhaust emissions produced by a diesel engine, wherein the system Includes: a particulate filter in the exhaust stream is included; a heat exchanger for adjusting the temperature of the diesel exhaust stream; and at least a catalytic NOx absorber in the temperature controlled diesel exhaust stream. Emission reduction system according to claim 1, wherein the diesel engine is suitable for driving a vehicle. The emission reduction system of claim 1, further a diesel oxidation catalyst in the exhaust stream. Emission reduction system according to claim 1, wherein the at least one NOx absorber at least two in parallel NOx absorber comprises; and wherein the emission reduction system further includes at least one valve, the exhaust gas flow optionally to the Can direct NOx absorbers. Emission reduction system according to claim 4, wherein the NOx absorbers can optionally be regenerated. Emission reduction system according to claim 4, further one to the NOx absorbers belonging System for injecting diesel fuel as a reducing agent wherein the reductant injection system is capable of to supply the NOx absorbers reducing agent for regeneration. Emission reduction system according to claim 1, wherein the at least one NOx absorber at least two in parallel NOx absorber comprises; and wherein the emission reduction system further includes at least one valve that is adapted to the NOx absorber optionally separate from the exhaust stream. Emission reduction system according to claim 1, wherein the exhaust flow to a temperature for improved operation of the at least one NOx absorber chilled becomes. Emission reduction system according to claim 8, wherein the temperature is 250 ° 450 ° C is. The emission reduction system of claim 1, further a heat source includes, which heat the exhaust stream can. Emission reduction system according to claim 10, wherein the heat source includes a burner powered by diesel fuel. Emission reduction system according to claim 10, wherein the heat source the exhaust gas flow to a temperature for improved operation of the particulate filter can. Emission reduction system according to claim 12, wherein the temperature is at least 270 ° C is. Emission reduction system according to claim 12, wherein the heat source the exhaust gas stream can heat to a temperature sufficient to to burn a substantial portion of the particles retained by the filter. Emission reduction system according to claim 10, wherein the heat source the exhaust gas flow to a temperature for improved operation heat the NOx absorber can. Emission reduction system according to claim 15, wherein the optimum temperature 250 ° C up to 450 ° C. The emission reduction system of claim 10, wherein the heat source is capable of sufficiently heating the exhaust flow at regular intervals to improve the capacity of the NOx absorbers, thereby releasing substances absorbed from the NOx that are related to the sulfur content of the diesel attributable to fuel. Emission reduction system according to claim 10, which further comprising a computing device that monitors the temperatures of the Monitor exhaust gas flow at the inlet of the filter and at the inlet of the first absorber can. Emission reduction system according to claim 18, wherein the computing device may further control the heat source to Set the temperature of the exhaust gas flow at the inlet of the filter. Emission reduction system according to claim 18, wherein the computing device may further control the heat source to the temperature of the exhaust stream at the entrance of at least one Adjust NOx absorber. Emission reduction system according to claim 18, wherein the computing device may further control the heat exchanger to the temperature of the exhaust stream at the entrance of the at least one NOx absorber adjust. Emission reduction system according to claim 1, wherein the heat exchanger a bypass path with a valve for selectively controlling the flowing through the bypass Includes exhaust stream. Method for controlling an exhaust emission reduction system for reducing the exhaust emissions generated by a diesel engine, the method comprising the following steps: (a) Monitor and controlling the temperature of the entering into a particulate filter Exhaust gas flow, which improves the functioning of the particulate filter becomes; and (b) Monitor and controlling the temperature of the entering into a catalytic NOx absorber Exhaust gas flow, whereby the operation of the NOx absorber is improved. The method of claim 23, further comprising the following Step includes: (c) entering the particulate filter Exhaust gas flow will open up at regular intervals set a temperature that is sufficient to a substantial Part of the particles retained by the particulate filter to burn. The method of claim 24, wherein the emission temperature of step (c) is at least 350 ° C. The method of claim 24, wherein step (c) is completed is when the differential pressure over the Particle filter over a predetermined level. The method of claim 23, further comprising the following Step includes: (d) the exhaust gas stream entering the absorber will open on a regular basis set a temperature sufficient to increase the capacity of the NOx absorber to improve, thereby absorbing substances from the NOx absorber be released, the sulfur content of the diesel fuel attributable to. The method of claim 27, wherein the emission temperature of step (d) is at least 500 ° C. The method of claim 23, wherein the exhaust stream temperature from step (a) at least 270 ° C is. The method of claim 23, wherein the exhaust stream temperature from step (b) between 250 ° C and 450 ° C is. A method according to claim 23, 24 or 27, wherein said Diesel engine is suitable for driving a vehicle. A computing device for controlling an exhaust emission reduction system for reducing the exhaust emissions produced by a diesel engine, wherein the emission reduction system a particulate filter, a catalytic NOx absorber and a heat transfer system includes, which heat the exhaust gas stream respectively or heat can deduct from this, wherein the computing device is a processor and software that are able to the temperature to monitor the exhaust gas flow entering the particulate filter, the Heat transfer system to control the temperature of the exhaust stream for improved operation to adjust the particulate filter; the temperature of the in the Monitor absorber entering exhaust gas stream; and the heat transfer system to control the temperature of the exhaust stream for improved operation of the absorber. A computing device according to claim 32, wherein the heat transfer system a heat source and a heat exchanger and wherein the processor and software are further incorporated in the Location are the heat source and the heat exchanger to control the temperature of the particulate filter and the NOx absorber entering the exhaust stream to adjust. The computing device of claim 32, wherein the processor and software may further monitor the pressure differential across the particulate filter; and can control the heat transfer system to Particles trapped by the particulate filter should be burned at regular intervals. The computing device of claim 32, wherein the processor and the software is further capable of controlling the heat transfer system, to adjust the temperature of the exhaust stream at regular intervals to the capacity of the NOx absorber to improve, thereby absorbing substances from the NOx absorbers be released, the sulfur content of the diesel fuel attributable to. A calculating device according to claim 33, 34 or 35, wherein the diesel engine is suitable for driving a vehicle and the processor and the software may further receive engine operating parameters.