SE540518C2 - Method and system for determining cleaning needs for a particle filter - Google Patents

Abstract

The present invention relates to a method for determining the cleaning need for a particle filter (265) of an engine (231) exhaust gas purification system from an ash occurrence point of view, comprising the steps of: - determining a measure of ash accumulation accumulated in said particle filter (265), and - determining (s340) ) said measure on the basis of determined heat capacity (C1; C2) of said particle filter (265) at at least two different states regarding accumulated ash occurrence.

Description

TECHNICAL FIELD The invention relates to a method for determining the cleaning needs of a particulate filter of an engine exhaust purification system from the point of view of ash occurrence. The invention also relates to a computer program product comprising program code for a computer for implementing a method according to the invention. The invention also relates to a system for determining the cleaning needs regarding a particulate filter of an engine exhaust purification system from an ash occurrence point of view and to a motor vehicle equipped with the system.

BACKGROUND Exhaust gas cleaning systems of today's motor vehicles include a number of different components. For example, an exhaust gas purification system may include a DOC unit (Diesel Oxidation Catalyst) arranged in a passage downstream of an internal combustion engine of the vehicle. Other components which may be arranged downstream of said engine are a DPF (Diesel Particulate Filter) unit and a SCR (Selective Catalytic Reduction) catalyst.

For many reasons, it is desirable to be able to diagnose individual components of exhaust gas cleaning systems of motor vehicles, such as, for example, trucks and buses. Diagnosis of components of exhaust gas purification systems of motor vehicles may, for example, be desirable in order to be able to determine the prevailing performance and / or function of the various components. Diagnosis of individual components in exhaust gas cleaning systems can in some states be subject to laws, regulations or directives, which of course vehicle manufacturers must comply with, not least from an environmental and competitive perspective.

Said DPF unit is arranged to capture e.g. soot and ash from an engine. Said soot and ash may come from the engine fuel or lubricant of the engine. Soot includes combustible substances while ash includes non-combustible substances. Soot is a term for the combustion residues that are formed when there is an excess of carbon in relation to oxygen. Ash is the solid residual product after combustion of organic substances. Soot can thus be at least partially incinerated, while ash can not be incinerated. Ash can be the non-combustible part of soot.

When soot and ash are stored in said DPF unit, a back pressure increases in the exhaust gas purification system. This contributes to unwanted parasitic losses of the system where useful work is used to force exhaust gases from the engine through said DPF unit. Either this will result in a reduction in the driving power of the vehicle's driveline or a fuel consumption of the engine will be increased in order to maintain the desired driving power of said driveline.

At certain intervals, said DPF unit may be actively regenerated to reduce or substantially eliminate the amount of soot stored. However, stored ash needs to be removed from said DPF unit manually with a certain regularity by means of, for example, compressed air. This procedure is time consuming, costly and often cumbersome for service personnel to perform.

Today, a degree of storage of said DPF unit with respect to ash can be determined by so-called dead count, wherein said storage rate of ash is continuously calculated according to a predetermined calculation model. This method can be based on an average value in terms of storage capacity for a number of different vehicle individuals and thus has shortcomings in accuracy for application in specific vehicle individuals. It should also be pointed out that engine oil consumption shows a large individual spread and variation over time that is significant.

Thus, today it is problematic to determine relevant intervals for service or replacement of DPF units in exhaust gas cleaning systems, for example in motor vehicles.

US20080264045 describes a method for determining whether it is sufficient to regenerate a particulate filter of an exhaust gas purification system or whether said particulate filter is in need of service. According to this method, a differential pressure across the particle filter is measured to measure a degree of filling here. In addition, an electrical resistance across said particulate filter is measured to determine if there is ash stored in said particulate filter or not.

OBJECT OF THE INVENTION There is thus a need to reliably determine the cleaning needs of a DPF unit of an exhaust gas purification system of a motor vehicle.

There is a need to diagnose a DPF device in an efficient, reliable and user-friendly way in terms of performance.

An object of the present invention is to provide a new and advantageous method for determining the cleaning need for a particle filter of an engine exhaust gas purification system from the point of view of ash occurrence.

An object of the present invention is to provide a new and advantageous method for performance control of a DPF unit of an exhaust gas purification system.

Another object of the invention is to provide a new and advantageous system for determining the cleaning needs of a particulate filter of an engine exhaust purification system from an ash occurrence point of view and a new and advantageous computer program for determining the cleaning requirements for a particulate filter of an engine exhaust purification system from an ash occurrence point of view.

A further object of the invention is to provide an alternative method for determining the cleaning needs of a particulate filter of an engine exhaust purification system from an ash occurrence point of view, an alternative system for determining a particulate filter cleaning needs of an engine exhaust gas purification system from an ash occurrence point of view and an alternative computer program for controlling for determining the cleaning needs regarding a particulate filter of an engine exhaust purification system from an ash occurrence point of view.

A further object of the invention is to provide a method of an exhaust gas purification system, an apparatus of an exhaust gas purification system and a computer program for providing a reliable performance check of a DPF unit of a motor vehicle.

A further object of the invention is to provide a method of an exhaust purification system, a system of an exhaust purification system and a computer program for providing a reliable performance check of a DPF unit of an SCR system, which SCR system may be installed in a motor vehicle.

SUMMARY OF THE INVENTION These and other objects, as set forth in the description below, are accomplished by a method and system as well as motor vehicles, computer programs and computer program products of the kind initially set forth and further having the features set forth in the characterizing part of the appended independent claims. Preferred embodiments of the method and system are defined in the appended dependent claims.

The embodiments of the system have the same advantages as the corresponding embodiments of the method mentioned above.

According to one aspect of the present invention, there is provided a method of determining cleaning requirements for a particulate filter of an engine exhaust purification system from an ash occurrence point of view. The method comprises the steps of: - determining a measure of ash accumulation accumulated in said particle filter; and - determining said dimensions on the basis of determined heat capacity of said particle filter in at least two different states regarding accumulated ash presence.

In this case, a first dimension is determined at a first state when no, or substantially no, ash is present in said particle filter. This constitutes a reference state and reflects a heat capacity of said particle filter without stored ash. In this case, a second dimension is determined in a second state when ash has accumulated in said particle filter. This constitutes a state which reflects a heat capacity of said particle filter when ash is stored. By comparing these two dimensions, ash occurrence can be determined in a simple, user-friendly, robust and reliable manner according to the inventive method. Furthermore, the inventive method is adapted to the specific vehicle / engine individual where said particle filter is arranged.

The method may comprise the steps of: - determining a first value of said heat capacity of said particulate filter based on a first state including determined parameter values regarding exhaust gas mass flow from said engine and a temperature difference regarding exhaust gas temperature upstream and downstream of said particulate filter and expected low ash occurrence; determining a second value of said heat capacity of said particulate filter based on the determination of said first value of said heat capacity and a second condition including determined parameter values regarding exhaust gas mass flow from said engine and a temperature difference regarding exhaust temperature upstream and downstream of said higher particulate filter. permission; and - determining said dimensions on the basis of a comparison between the two values of said heat capacity thus determined. Said comparison may comprise comparing an absolute difference or absolute ratio with respect to the two values thus determined of said heat capacity with a respective adequate threshold value.

By considering a temperature inertia of the particulate filter, which largely depends on the amount of ash stored, said measure of ash accumulation accumulated in said particulate filter can be determined in a user-friendly and reliable manner. The thermal inertia of said particle filter depends on the amount of soot and ash stored. In this case, it is important to point out that stored ash has a large effect on the thermal inertia of the particle filter relative to a stored amount of soot. Density of ash is on the order of 10 times higher than that of soot.

By determining heat energies based on prevailing exhaust mass flows and said temperature difference regarding exhaust temperature upstream and downstream of said particle filter for said two different states, the equation below can be used according to an aspect of the present invention.

MF 1 x C 1 x l? T1 | = MF2 x C2 x |? T2 | In this case, a first heat energy of the system in a first state is determined by multiplying an prevailing exhaust gas mass flow MF1 by a measure of heat capacity C1 and an absolute difference |? T1 | between said exhaust temperatures upstream and downstream of said particle filter. Said first measure of heat capacity C1 can be determined in a suitable manner, when substantially no ash is present in said particle filter. This can be done, for example, when the vehicle leaves a manufacturing plant.

In this case, said second measure of heat capacity C2, in a second state, can be calculated by said energy relationship, on the basis of a determined second exhaust mass flow MF2 and an absolute difference \ ?? 2 \ between said exhaust temperatures upstream and downstream of said particle filter in said second state.

The method may comprise the step of: - determining said values of said heat capacity in connection with transient processes regarding exhaust gas temperature upstream and / or downstream of said particle filter; and / or - determining said values of said heat capacity when a determined absolute temperature difference with respect to exhaust gas temperature upstream and downstream of said particle filter exceeds a predetermined value. Hereby an accurate way is provided to determine a measure of ash accumulation accumulated in said particle filter.

The method may comprise the step of: - regenerating said particulate filter with respect to soot particles before determining said measure of accumulated ash occurrence. In this case, said particle filter advantageously comprises only ash, which provides a reliable method for determining the ash presence of said particle filter.

The method may comprise the step of: - predicting the need for removal of ash from said particulate filter based on determining the evolution of said dimension over time. In this case, an operator of said engine with exhaust gas cleaning system, including a particle filter, can become aware and plan in good time to clean or replace said particle filter. Advantageously, more adequate service intervals for said particle filter can be provided compared to prior art. This entails a reduced risk of storing excessive amounts of ash in the particulate filter, which is advantageous from the point of view of performance, among other things.

The method may comprise the steps of: - determining the need to remove accumulated ash from said particulate filter at a predetermined value reached for said dimension; and - in the event of an established need to remove accumulated ash from said particulate filter, for an operator of said engine, indicate said need. In this case, an operator of said engine with exhaust gas cleaning system, including a particle filter, can become aware and plan in good time to clean or replace said particle filter. Advantageously, more adequate service intervals for said particle filter can be provided compared to prior art. This entails a reduced risk of storing excessive amounts of ash in the particulate filter, which is advantageous from the point of view of performance, among other things.

According to one aspect of the present invention, there is provided a system for determining the cleaning requirement for a particulate filter of an engine exhaust purification system from an ash occurrence point of view, comprising: - means adapted to determine a measure of ash accumulation accumulated in said particulate filter; and - means adapted to determine said dimension on the basis of determined heat capacity of said particle filter at at least two different states regarding accumulated ash presence.

The system may comprise: means adapted to determine a first value of said heat capacity of said particulate filter based on a first state including determined parameter values regarding exhaust gas mass flow from said engine and a temperature difference regarding exhaust temperature upstream and downstream of said particulate filter and expected low ash occurrence; means adapted to determine a second value of said heat capacity of said particulate filter based on the determination of said first value of said heat capacity and a second condition including determined parameter values regarding exhaust mass flow from said engine and a temperature difference regarding exhaust temperature upstream and downstream of said particulate filter. relative to said first state; and - means adapted to determine said dimensions on the basis of a comparison between the two values of said heat capacity thus determined.

The system may comprise: - means adapted to determine said values of said heat capacity in connection with transient processes regarding exhaust gas temperature upstream and / or downstream of said particle filter; and / or means adapted to determine said values of said heat capacity when a determined absolute temperature difference with respect to exhaust gas temperature upstream and downstream of said particle filter exceeds a predetermined value.

The system may comprise: - means adapted to regenerate said particulate filter with respect to soot particles before said measurement with respect to accumulated ash occurrence is determined.

The system may comprise: - means adapted to predict the need for removal of ash from said particle filter based on determining the development of said measure over time.

The system may comprise: - means adapted to determine the need to remove accumulated ash from said particle filter at a predetermined value reached for said dimension; and means adapted to indicate to an operator of said engine, at an determined need to remove accumulated ash from said particulate filter, an operator of said engine.

According to one aspect of the present invention, there is provided a motor vehicle comprising a system according to any one of claims 7-12.

The motor vehicle can be anything from a truck, bus or car.

According to one aspect of the present invention, there is provided a computer program of an exhaust gas purification system, said computer program comprising program code for causing an electronic control unit or a computer connected to the electronic control unit to perform the steps of any of claims 1-6.

According to one aspect of the present invention, computer programs are provided in an exhaust gas purification system, said computer program comprising program code for causing an electronic control unit or a computer connected to the electronic control unit to perform the steps of any of claims 1-6, when said program code is run at said control unit or said computer.

According to one aspect of the present invention, computer programs are provided in an exhaust gas purification system, said computer program comprising program code stored on a computer readable medium for causing an electronic control unit or a computer connected to the electronic control unit to perform the steps of any of claims 1- 6.

According to one aspect of the present invention, computer programs are provided in an exhaust gas purification system, said computer program comprising program code stored on a computer readable medium for causing an electronic control unit or a computer connected to the electronic control unit to perform the steps of any of claims 1- 6, when said program code is executed at said control unit or said computer.

According to one aspect of the present invention, there is provided a computer program product comprising a program code stored on a computer readable medium for performing the method steps of any of claims 1-6, when said program code is executed on an electronic control unit or a computer connected to the electronic control unit. .

According to one aspect of the present invention, there is provided a computer program product comprising a program code non-volatilely stored on a computer readable medium for performing the method steps of any of claims 1-6, when said program code is run on an electronic control unit or another computer connected to the electronic control unit.

Additional objects, advantages, and novel features of the present invention will become apparent to those skilled in the art from the following details, as well as through practice of the invention. While the invention is described below, it should be understood that the invention is not limited to the specific details described. Those skilled in the art having access to the teachings herein will recognize additional applications, modifications, and incorporations within other fields which are within the scope of the invention.

SUMMARY DESCRIPTION OF THE DRAWINGS The present invention will be better understood with reference to the following detailed description read in conjunction with the accompanying drawings, in which like reference numerals refer to like parts throughout the many views, and in which: Figure 1 schematically illustrates a vehicle, according to a embodiment of the invention; Figure 2 schematically illustrates a subsystem of the vehicle shown in Figure 1, according to an embodiment of the invention; Figure 3a schematically illustrates a flow chart of a method, according to an embodiment of the invention; Figure 3b schematically illustrates in further detail a flow chart of a method, according to an embodiment of the invention; and Figure 4 schematically illustrates a computer, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE FIGURES Referring to Figure 1, a side view of a vehicle 100 is shown. The exemplary vehicle 100 consists of a tractor 110 and a trailer 112. The vehicle may be a heavy vehicle, such as a truck or a bus. The vehicle can alternatively be a car.

Here, the term "link" refers to a communication link which may be a physical line, such as an optoelectronic communication line, or a non-physical line, such as a wireless connection, for example a radio or microwave link.

Here, the term "reductant" or "reducing agent" refers to an agent used to react with certain emissions in an SCR system of the engine exhaust system. These emissions can e.g. be NOx gas. Said reductant is according to an embodiment so-called AdBlue. Of course, other types of reductants can be used.

It should be noted that the invention is suitable for application to a suitable exhaust gas purification system comprising a DPF unit. The inventive method and the inventive system are well suited for platforms which include an exhaust gas purification system other than motor vehicles, such as e.g. watercraft. The watercraft can be of any kind, such as e.g. motorboats, ships, ferries or ships.

The inventive method and the inventive system in an exhaust gas purification system according to an aspect of the invention are also well suited for e.g. systems including tractors, dumpers, power tools, industrial engines and / or powered industrial robots.

The inventive method and the inventive system in an exhaust gas purification system according to an aspect of the invention are also well suited for different types of power plants, such as e.g. an electric power plant comprising a diesel generator.

The inventive method and inventive system of an exhaust gas purification system is well suited for any engine system which includes an engine, DPF unit and optionally an SCR system, such as e.g. at a locomotive or other platform.

The inventive method and the inventive system of an exhaust gas purification system are well suited for a system which includes a generator and a DPF unit, for example a diesel engine, the exhaust gases of which are to be purified.

Fig. 2 schematically illustrates a subsystem 289 of the vehicle 100 shown in Fig. 1, according to an embodiment of the invention. Said subsystem 289 forms part of an exhaust gas purification system of the vehicle 100.

An engine 231 is provided, which during operation causes an exhaust gas flow which is led via a first passage 235 to a DOC unit 260. A second passage 245 is arranged to direct exhaust gases from said DOC unit 260 to a DPF unit 265. Said DPF Unit 265 includes a Diesel Particulate Filter. A third passage 255 is arranged to direct exhaust gases from said DPF unit 265 to an SCR catalyst arrangement 270. Said SCR catalyst arrangement 270 may alternatively be called SCR catalyst. A fourth passage 256 is provided to direct exhaust gases from said SCR catalyst arrangement 270 to an environment of the vehicle 100.

According to an alternative embodiment, said DOC unit 260 and / or said SCR catalyst 270 may be omitted.

In the event that said exhaust gas purification system comprises an SCR catalyst 270, a dosing unit (not shown) is provided, which is arranged to dispense reducing agent into said third passage 255 for catalytic exhaust purification for NOx gas.

The first control unit 200 is arranged for communication with the motor 231 via a link L231. The first control unit 200 is arranged to control the operation of said engine 231. The first control unit 200 is for instance arranged to control fuel metering to the combustion chamber of said engine 231.

Fuel metering means (not shown) may be arranged upstream of said DOC unit 260 and downstream of said engine 231. The first control unit 200 is arranged for communication with said fuel metering means via a dedicated link (not shown). The first control unit 200 is arranged to control the dosing of fuel, for example diesel, into said first passage 235 by means of said fuel dosing means in order to effect a so-called active regeneration of said DPF unit 265.

A first temperature sensor 237 is arranged upstream of said DPF unit 265 at said second passage 245. Said first temperature sensor 237 is arranged for communication with the first control unit 200 via a link L237. Said first temperature sensor 237 is arranged to continuously measure / detect / determine a prevailing first temperature T1 of the exhaust gases in the second passage 245. Said first temperature sensor 237 is arranged to continuously send signals S237 including information about said prevailing first temperature T1 of the exhaust gases in said second passage 245 to the first control unit 200 via the link L237.

A second temperature sensor 277 is arranged downstream of said DPF unit 265 at said third passage 255. Said second temperature sensor 277 is arranged for communication with the first control unit 200 via a link L277. Said second temperature sensor 277 is arranged to continuously measure / detect / determine a prevailing second temperature T2 of the exhaust gases in the third passage 255. Said second temperature sensor 277 is arranged to continuously send signals S277 including information about said prevailing second temperature T2 of the exhaust gases in said third passage 255 to the first control unit 200 via the link L277.

According to an exemplary embodiment, a third temperature sensor 233 may be arranged upstream of said DOC unit 260 at said first passage 235. Said third temperature sensor 233 is arranged for communication with the first control unit 200 via a link L233. Said third temperature sensor 233 is arranged to continuously measure / detect / determine a prevailing third temperature T3 of the exhaust gases in the first passage 233. Said third temperature sensor 233 is arranged to continuously send signals S233 including information about said prevailing third temperature T3 of the exhaust gases in said first passage 233 to the first control unit 200 via the link L233.

According to one aspect of the present invention, said first temperature T1 and said second temperature T2 are used to determine a temperature difference across said DPF unit 265, whereby a prevailing heat capacity can be determined according to the inventive method. According to an alternative embodiment, said third temperature T3 and said second temperature T2 may be used to determine a temperature difference across said DPF unit 265 and said DOC unit, a prevailing heat capacity for the combination of said DPF unit 265 and said DOC unit 260. of can be determined and used in a congruent manner (regarding the use of the temperatures T1 and T2) according to an aspect of the inventive process. This embodiment is not described in further detail here.

A sensor (not shown) for measuring a prevailing exhaust mass flow MF may be provided in the first passage 235. Said exhaust mass flow sensor is arranged to continuously determine a prevailing exhaust mass flow MF in the first passage 235 and send signals including the first control unit 200 thereto. via a dedicated link (not shown).

According to one embodiment, the first control unit 200 is arranged to determine by means of a calculation model stored therein an prevailing exhaust mass flow MF in the first passage 235. Said prevailing exhaust mass flow MF in the first passage 235 can be determined on the basis of e.g. a determined operating state of the motor 231.

An exhaust mass flow determined at said first state (when substantially no ash is stored in said DPF unit 265) is referred to herein as MF1 and an exhaust mass flow determined at said second state (when a certain amount of ash is stored in said DPF unit 265) is referred to herein. as MF2.

The first control unit 200 may be arranged to determine a measure of ash accumulation accumulated in said particle filter 265. This can be done by determining said measure on the basis of determined heat capacity of said particle filter 265 at at least two different states regarding accumulated ash occurrence.

The first control unit 200 may be arranged to determine a first value C1 of said heat capacity of said particle filter 265 based on a first state including determined parameter values regarding exhaust gas flow MF1 from said engine 231 and a temperature difference T1-T2 or T3-T2 regarding exhaust temperature upstream and downstream, respectively. said particle filter 265 and expected low ash occurrence.

The first control unit 200 may be arranged to determine a second value C2 of said heat capacity of said particle filter 265 based on the determination of said first value C1 of said heat capacity and a second state including determined parameter values regarding exhaust mass flow MF2 from said engine 231 and a temperature difference T1 T2 or T3-T2 regarding exhaust temperature upstream and downstream of said particle filter 265 and expected higher ash occurrence relative to said first state.

The first control unit 200 may be arranged to determine said dimensions on the basis of a comparison between the two values C1 and C2 thus determined on said heat capacity.

The first control unit 200 may be arranged to determine said dimensions on the basis of a comparison between an absolute difference, | C1-C2 | , between the two values C1 and C2 thus determined and a predetermined threshold value TH1. In the event that said absolute difference between the two values C1 and C2 thus determined exceeds said threshold value TH1, this is taken as an indication that said particle filter 265 should / should be cleaned or replaced within a certain period of time, for example substantially immediately, as soon as possible or after a maximum number of operating hours with the engine 231, for example 10, 100 or 200 hours.

The first control unit 200 may be arranged to determine said dimension on the basis of a comparison between an absolute ratio C1 / C2 between the two values C1 and C2 thus determined and a predetermined threshold value TH2. In the event that said absolute ratio C1 / C2 between the two values C1 and C2 thus determined falls below said threshold value TFI2, this is taken as an indication that said particle filter 265 should / should be cleaned or replaced within a certain period of time, for example substantially immediately, as soon as possible or after a maximum number of operating hours with the engine 231, for example 10, 100 or 200 hours.

The first control unit 200 may be arranged to determine said values C1 and C2 on said heat capacity in connection with transient processes regarding exhaust temperature T1 or T3 upstream of said particle filter 265. The first control unit 200 may be arranged to determine said values C1 and C2 on said heat capacity in connection with transient processes regarding exhaust temperature T2 downstream of said particle filter. The first control unit 200 may be arranged to determine a suitable time for determining said values C1 and C2 on the basis of the prevailing operating conditions of the engine 231, said operating state advantageously including transient temperature courses with respect to said exhaust gas temperature and / or exhaust gas mass flow MF.

The first control unit 200 may be arranged to determine said values C1 and C2 at said heat capacity when a determined absolute temperature difference with respect to exhaust gas temperature upstream and downstream of said particle filter exceeds a predetermined value THtemp. Said predetermined value THtemp may be any suitable value. Said predetermined value THtemp is a zero value, for example 10, 50 or 100 degrees Celsius. In principle, a larger value of THtemp is better than a lower value.

The first control unit 200 may be arranged to regenerate said particle filter 265 with respect to soot particles before said measurement with respect to accumulated ash occurrence is determined.

The first control unit 200 may be arranged to predict the need to remove ash from said particle filter 265 based on determining the evolution of said dimension over time.

The first control unit 200 may be arranged to determine the need to remove accumulated ash from said particle filter 265 at a predetermined value reached with respect to said dimension. The first control unit 200 may be arranged to indicate, if a determined need to remove accumulated ash from said particle filter 265, for an operator of said engine 231, said need. This can be done by means of presentation means 220.

Presentation means 220 are arranged for communication with said first control unit 200 via a link L220. The first control unit 200 is arranged to present a result of performance control of said DPF unit 265. Said result may indicate, for example, "no presence of ash in DPF unit", "low presence of ash in DPF unit", "medium occurrence of ash in DPF unit". DPF unit, cleaning is recommended shortly "or" high presence of ash in DPF unit, cleaning / replacement should be performed immediately ". For example, a degree of ash occurrence / impairment of the DPF unit 265 can be presented, this degree of ash occurrence / impairment can be stated in percent. Said display means 220 may include speakers for reproducing synthesized voice or other audible feedback. Said display means 220 may comprise a display screen, for example a so-called touch screen for visual feedback of said results.

A second control unit 210 is arranged for communication with the first control unit 200 via a link L210. The second control unit 210 may be releasably connected to the first control unit 200. The second control unit 210 may be a control unit external to the vehicle 100. The second control unit 210 may be arranged to perform the inventive method steps. The second control unit 210 can be used to upload program code to the first control unit 200, in particular program code for performing the inventive method. The second control unit 210 may alternatively be arranged for communication with the first control unit 200 via an internal network in the vehicle. The second control unit 210 may be arranged to perform substantially the same functions as the first control unit 200.

Figure 3a schematically illustrates a flow chart of a method for determining cleaning needs regarding a particulate filter 265 of an engine 231 exhaust gas purification system from an ash occurrence point of view. The method includes a process step s301. Step s301 comprises the steps of: - determining a measure of ash accumulation accumulated in said particle filter 265 - determining said measure on the basis of determined heat capacity C1, C2 of said particle filter 265 at at least two different states regarding accumulated ash occurrence. After procedure step s301, the procedure is terminated.

Fig. 3b schematically illustrates in further detail a flow chart of a method for determining cleaning needs regarding a particle filter 265 of an engine 231 exhaust gas purification system from an ash occurrence point of view. The method includes a step step s310.

The method step s310 comprises the step of, in a first state, determining a prevailing exhaust mass flow MF1 from said engine 231. This can be performed by means of a suitable sensor or by means of a calculation model stored in a memory of the first control unit 200.

The method step s310 comprises the step of, in a first state, determining a first or a third temperature value T1, T3 downstream of said motor 231 and upstream of said particulate filter 265. The method step s310 comprises the step of, in a first state, determining a second temperature value T2 downstream of said particulate filter 265. This can be done by means of a suitable sensor or by means of a calculation model stored in a memory of the first control unit 200.

The method step s310 comprises the step of determining a first value C1 of said heat capacity of said particle filter 265 based on said first state including determined parameter values regarding exhaust mass flow MF1 from said engine 231 and at least one of said temperature differences T1-T2, T3-downstream and said particle filter 265 and expected low ash occurrence. By using the energy expression MF 1 x C 1 x |? T1 | and a suitable constant, said first value C1 can be determined. The absolute amount |? T1 | refers to a first temperature difference at the first state, where |? T1 | is equal to the temperature difference T1-T2 or T3-T2.

Said value C1 of said heat capacity can be determined in connection with transient processes with respect to exhaust gas temperature upstream and / or downstream of said particle filter 265.

Said value C1 of said heat capacity can be determined when a determined absolute temperature difference with respect to exhaust gas temperature upstream and downstream of said particle filter 265 exceeds a predetermined value THtemp.

After step s310, a subsequent process step s320 is performed.

The method step s320 comprises the step of, in a second state, determining a prevailing exhaust mass flow MF2 from said engine 231. This can be performed by means of a suitable sensor or by means of a calculation model stored in a memory of the first control unit 200.

Method step s320 comprises the step of, in a second condition, determining a first or a third temperature value T1, T3 downstream of said motor 231 and upstream of said particulate filter 265. Method step s320 comprises the step of determining, in a second condition, a second temperature value T2 downstream of said particulate filter 265. This can be done by means of a suitable sensor or by means of a calculation model stored in a memory of the first control unit 200.

The method step s320 comprises the step of determining a second value C2 of said heat capacity of said particle filter 265 based on the determination of said first value C1 of said heat capacity and a second condition including determined parameter values regarding exhaust mass flow MF2 from said engine 231 and a temperature difference T1, T2 difference -T2 regarding exhaust temperature upstream and downstream of said particle filter 265 and expected higher ash occurrence relative to said first state.

By using the energy expression MF 1 x C 1 x |? T1 | = MF2 x C 2 x |? T2 | the second value C2 can be triggered.

The absolute amount \ ?? 2 \ refers to a first temperature difference at the second state, where |? T2 | is equal to the temperature difference T1-T2 or T3-T2.

Said value C2 of said heat capacity can be determined in connection with transient processes with respect to exhaust gas temperature upstream and / or downstream of said particle filter 265.

Said transient course of exhaust gas temperature may be associated with transient courses of said exhaust mass flow from said engine 231.

Said value C2 of said heat capacity can be determined when an determined absolute temperature difference with respect to exhaust gas temperature upstream and downstream of said particle filter 265 exceeds a predetermined value THtemp.

After step s320, a subsequent process step s330 is performed.

The method step s330 comprises the step of comparing the two values C1, C2 thus determined on said heat capacity. In this case, an absolute difference between C1 and C2 can be compared with a predetermined threshold value TH1. In this case, an absolute ratio between C1 and C2 can be compared with a predetermined threshold value TH2.

After step s330, a subsequent process step s340 is performed.

Method step s340 comprises the step of determining said measure of ash accumulation accumulated in said particle filter 265 on the basis of said comparison of determined heat capacities C1 and C2 of said particle filter 265 at said at least two different states regarding accumulated ash occurrence.

Method step s340 may include the step of determining the need to remove accumulated ash from said particle filter 265 at a predetermined value reached for said dimension.

After step s340, a subsequent process step s350 is performed.

The method step s350 may comprise the step of presenting / indicating said need, to an operator of said engine 231 or vehicle 100, in the event of a determined need to remove accumulated ash from said particle filter. This can be done by means of said presentation means 220.

After step s350, the procedure is terminated.

Referring to Figure 4, there is shown a diagram of an embodiment of a device 500. The controllers 200 and 210 described with reference to Figure 2 may in one embodiment include the device 500. The device 500 includes a non-volatile memory 520, a data processing unit 510, and a read / write memory 550. The non-volatile memory 520 has a first memory portion 530 in which a computer program, such as an operating system, is stored to control the operation of the device 500. Further, the device 500 includes a bus controller, a serial communication port, 1 I / O means, an A / D converter, a time and date input and transfer unit, an event counter and an interrupt controller (not shown). The non-volatile memory 520 also has a second memory portion 540.

A computer program P is provided for determining the cleaning needs of a particulate filter 265 of an engine 231 exhaust gas purification system from the ash occurrence point of view.

The computer program P may include routines for determining a measure of ash accumulation accumulated in said particle filter 265.

The computer program P may comprise routines for determining said dimensions on the basis of determined heat capacity C1, C2 of said particle filter 265 in at least two different states regarding accumulated ash occurrence.

The computer program P may comprise routines for determining a first value C1 of said heat capacity of said particle filter 265 based on a first state including determined parameter values regarding exhaust gas flow MF1 from said engine 231 and a temperature difference T1-T2, T3-T2 regarding exhaust gas temperature upstream of said upstream. particulate filter 265 and expected low ash content.

The computer program P may include routines for determining a second value C2 of said heat capacity of said particle filter 265 based on the determination of said first value C1 of said heat capacity and a second condition including determined parameter values regarding exhaust mass flow MF2 from said engine 231 and a temperature difference T1 , T3-T2 regarding exhaust temperature upstream and downstream of said particle filter 265 and expected higher ash occurrence relative to said first state. The computer program P may comprise routines for determining said dimensions on the basis of a comparison between the two values thus determined of said heat capacity C1, C2. This can be done by comparing an absolute difference between said first heat capacity C1 and said second heat capacity C2 with a predetermined value TH1. This can be done by comparing an absolute ratio between said first heat capacity C1 and said second heat capacity C2 with a predetermined value TFI2.

The computer program P may comprise routines for determining said values C1, C2 of said heat capacity in connection with transient processes with respect to exhaust gas temperature upstream of said particle filter 265; and / or - routines for determining said values C1, C2 on said heat capacity when a determined absolute temperature difference with respect to exhaust gas temperature upstream and downstream of said particle filter 265 exceeds a predetermined value THtemp.

The computer program P may comprise routines for determining said values C1, C2 on said heat capacity in connection with transient processes regarding exhaust gas temperature downstream of said particle filter.

The computer program P may include routines for controlling regeneration of said particulate filter 265 with respect to soot particles before said measurement of accumulated ash occurrence is determined.

The computer program P may include routines for predicting the need to remove ash from said particle filter 265 based on determining the evolution of said measure over time.

The computer program P may include routines for determining the need to remove accumulated ash from said particle filter 265 at a predetermined value reached for said dimension; and - routines for indicating, for an operator of said engine 231, at an determined need to remove accumulated ash from said particulate filter 265, for an operator of said engine 231.

The program P can be stored in an executable manner or in a compressed manner in a memory 560 and / or in a read / write memory 550.

When it is described that the data processing unit 510 performs a certain function, it is to be understood that the data processing unit 510 performs a certain part of the program which is stored in the memory 560, or a certain part of the program which is stored in the read / write memory 550.

The data processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via a data bus 511. Read / write memory 550 is arranged to communicate with the data processing unit 510 via a data bus 514. To the data port 599, e.g. the links L210, L220, L231, L233, L237, L277, are connected (see Figure 2).

When data is received on the data port 599, it is temporarily stored in the second memory part 540. Once the received input data has been temporarily stored, the data processing unit 510 is arranged to perform code execution in a manner described above. According to one embodiment, signals received at the data port 599 include information on Parts of the methods described herein may be performed by the device 500 using the data processing unit 510 running the program stored in the memory 560 or read / write memory 550. When the device 500 runs the program, the methods described herein are executed.

The foregoing description of the preferred embodiments of the present invention has been provided for the purpose of illustrating and describing the invention. It is not intended to be exhaustive or to limit the invention to the variations described. Obviously, many modifications and variations will occur to those skilled in the art. The embodiments were selected and described to best explain the principles of the invention and its practical applications, thereby enabling those skilled in the art to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims (14)

A method for determining the cleaning need for a particulate filter (265) of an engine (231) exhaust gas purification system from an ash occurrence point of view, comprising the step of: - determining a measure of ash accumulation accumulated in said particulate filter (265), characterized by the step of: - determining (s301) ; s340) said measure based on the determined heat capacity (C1; C2) of said particle filter (265) at at least two different states regarding accumulated ash occurrence; further comprising the step of: - determining (s310; s320) said values (C1; C2) of said heat capacity in connection with transient processes of exhaust gas temperature upstream and / or downstream of said particle filter (265); and - determining (s310; s320) said values (C1; C2) of said heat capacity when a determined absolute temperature difference with respect to exhaust gas upstream and downstream of said particle filter (265) exceeds a predetermined value (THtemp). A method according to claim 1, comprising the step of: - determining (s310) a first value (C1) of said heat capacity of said particle filter (265) based on a first state including determined parameter values regarding exhaust mass flow (MF1) from said engine (231) and a temperature difference (T1-T2, T3-T2) regarding exhaust gas temperature upstream and downstream of said particle filter (265) and expected low ash occurrence; determining (s320) a second value (C2) of said heat capacity of said particle filter (265) based on the determination of said first value (C1) of said heat capacity and a second condition including determined parameter values regarding exhaust mass flow (MF2) from said engine (231 ) and a temperature difference (T1-T2, T3-T2) regarding exhaust temperature upstream and downstream of said particle filter (265) and expected higher ash occurrence relative to said first state; and - determining (s330, s340) said measure on the basis of a comparison between the two values thus determined (C1, C2) of said heat capacity. A method according to any one of the preceding claims, comprising the step of: - regenerating said particle filter (265) with respect to soot particles before determining said measure regarding accumulated ash occurrence. A method according to any one of the preceding claims, comprising the step of: - predicting the need to remove ash from said particle filter (265) based on determining the evolution of said dimension over time. A method according to any one of the preceding claims, comprising the step of: - determining the need (s340) to remove accumulated ash from said particle filter (265) at a predetermined value reached for said dimension; and - in the event of an established need to remove accumulated ash from said particulate filter, for an operator of said engine (231), present / indicate (s350) said need. A system for determining the cleaning requirement for a particulate filter (265) of an engine (231) exhaust gas purification system from an ash occurrence point, comprising: - means (200; 210; 500) adapted to determine a measure of ash accumulation accumulated in said particulate filter (265), characterized by: - means (200; 210; 500) adapted to determine said measure on the basis of determined heat capacity (C1; C2) of said particle filter (265) at at least two different states regarding accumulated ash occurrence; means (200; 210; 500) adapted to determine said values (C1; C2) of said heat capacity in connection with transient processes of exhaust gas upstream and / or downstream of said particulate filter (265); and - means (200; 210; 500) adapted to determine said values (C1; C2) of said heat capacity when a determined absolute temperature difference with respect to exhaust gas upstream and downstream of said particle filter (265) exceeds a predetermined value (THtemp). A system according to claim 6, comprising: - means (200; 210; 500) adapted to determine a first value (C1) of said heat capacity of said particle filter (265) based on a first state including determined parameter values regarding exhaust mass flow (MF1) from said engine (231) and a temperature difference (T1-T2; T3-T2) regarding exhaust temperature upstream and downstream of said particle filter (231) and expected low ash occurrence; means (200; 210; 500) adapted to determine a second value (C2) of said heat capacity of said particulate filter (265) based on the determination of said first value (C1) of said heat capacity and a second condition including determined parameter values regarding exhaust gas mass flow ( MF2) from said engine (231) and a temperature difference (T1-T2; T3-T2) regarding exhaust temperature upstream and downstream of said particle filter (265) and expected higher ash occurrence relative to said first state; and - means (200; 210; 500) adapted to determine said dimensions on the basis of a comparison between the two values thus determined (C1, C2) of said heat capacity. A system according to any one of claims 6-7, comprising: - means (200; 210; 500; 260) adapted to regenerate said particulate filter (265) with respect to soot particles before said measurement of accumulated ash occurrence is determined. A system according to any one of claims 6-8, comprising: - means (200; 210; 500) adapted to predict the need to remove ash from said particle filter (265) based on determining the evolution of said dimension over time. A system according to any one of claims 6-9, comprising: - means (200; 210; 500) adapted to determine the need to remove accumulated ash from said particle filter (265) at a predetermined value reached for said dimension; and means (200; 210; 500; 220) adapted to indicate to an operator of said engine, at an determined need to remove accumulated ash from said particulate filter (265), for an operator of said engine. A motor vehicle (100; 110) comprising a system according to any one of claims 6-10 A motor vehicle (100; 110) according to claim 11, wherein the motor vehicle is something of a truck, bus or passenger car. Computer program (P) in an exhaust gas purification system, said computer program (P) comprising program code for causing an electronic control unit (200; 500) or a computer (210; 500) connected to the electronic control unit (200; 500) to perform the steps according to any one of claims 1 -5. A computer program product comprising a program code stored on a computer readable medium for performing the method steps according to any one of claims 1 to 5, when said program code is executed on an electronic control unit (200; 500) or a computer (210; 500) connected to the electronic control unit (200; 500).