SE1150863A1 - Method of an HC dosing system and an HC dosing system - Google Patents

Abstract

The invention relates to a method of an HC dosing system for exhaust gas purification, in which fuel is supplied to a supply device (230), by means of which supply device (230) fuel is supplied to a dosing unit (250) for batch supply of fuel by means of a valve arrangement (350, 360) at a consumption point of the HC dosing system. The method comprises the steps of: - continuously determining (s410) by said dosing unit (250) accumulated number of dosing performed (N); - continuously comparing (s420, s430) said accumulated number of doses performed (N) with a predetermined number value (TH), and - giving an indication (s440) when said accumulated number of doses performed (N) exceeds said predetermined number value (TH). also a computer program product comprising program code (P) for a computer (200; 210; 500) for implementing a method according to the invention. The invention also relates to an HC dosing system and a motor vehicle (100; 110) equipped with the HC dosing system. Figure 2 for publication

Description

15 20 25 30 e.g. at an exhaust pipe of the exhaust system. The container can be the vehicle's fuel tank or a separate container of the DPF system. The dosing unit is arranged to inject a required amount of diesel into the exhaust pipe upstream of the particulate filter according to drivers stored in a control unit of the vehicle. In order to more easily regulate the pressure at small or no dosage amounts, the system may also comprise a return hose which is arranged from a pressure side of the system back to the container.

According to a first example, a service life of a dosage unit is defined as a predetermined period of time. A change interval for the dosing unit can thus be a fixed time interval, such as e.g. two years.

According to a second example, a service life of a dosing unit is defined as a certain predetermined mileage. it is recommended to replace the dosing unit after a number of kilometers driven. These recommendations are in some cases implemented as a service measure for the vehicle in question, which means that service personnel at a vehicle service check how many kilometers have been driven since the last change of dosing unit.

According to a third example, a service life of a dosage unit is defined as a predetermined service life. In this case, the dosing unit after a predetermined period of use, e.g. 25,000 hours. it is recommended to replace Some types of dosing units are arranged to dose fuel according to a predetermined cycle frequency. A normal cycle frequency is 1Hz. In some vehicles, such as is carried out with periodically high loads, however, it is desirable to control dosing according to a higher cycle frequency, such as e.g. 2, 4, 10 or 20Hz.

During each cycle, dosing can take place at any time interval, e.g. 0.2 or 0.5 seconds, or throughout the cycle, i.e. 1 second where the cycle frequency is 1Hz. Alternatively, it may be desirable to use a lower cycle frequency, e.g. 0.5Hz, in some applications. SUMMARY OF THE INVENTION When a setting of the cycle frequency of the dosing unit is changed from a basic setting of e.g. 1Hz to e.g. 2Hz affects the expected life of the dosing unit.

In light of what has been described above, there is thus a need to improve the current HC dosing system by reducing or eliminating it. It is desirable to provide an HC dosing system that can be adapted to a cycle frequency that differs from the above mentioned disadvantages. a normal value, e.g. 1Hz.

An object of the present invention is to provide a new and advantageous method in an HC dosing system.

Another object of the invention is to provide a new and advantageous HC dosing system for exhaust gas purification, and a new and advantageous computer program for an HC dosing system.

A further object of the invention is to provide a method, an HC dosing system and a computer program for providing a robust way of optimizing a change interval of a dosing unit which can have any discrete cycle frequency.

A further object of the invention is to provide a method, a HC dosing system and a computer program for reducing a risk that the performance of an HC dosing system deteriorates too much over time.

A further object of the invention is to provide a method, an HC dosing system and a computer program for in a cost-effective manner to achieve improved performance of an HC dosing system, where an optimized use of a fuel dosing unit of said HC dosing system is provided.

A further object of the invention is to provide a method, an HC dosing system and a computer program for in a cost-effective and user-friendly manner to provide an improved HC dosing system, where a cycle frequency of the dosing unit can be changed between different fixed values.

A further object of the invention is to provide an alternative method, an alternative HC dosing system and an alternative computer program for achieving improved performance of an HC dosing system.

These objects are achieved with a method of HC dosing system for exhaust gas purification according to claim 1.

According to one aspect of the invention, there is provided a method of an HC dosing system for exhaust gas purification, wherein fuel is supplied to a supply device, by means of which supply device fuel is supplied to a dosing unit for batch supply of fuel by means of a valve arrangement at a consumption point of the HC dosing system. The method comprises the steps of: - continuously determining by said dosing unit the accumulated number of performed doses; - continuously compare said accumulated number of performed dosages with a predetermined number value, and - give an indication when said accumulated number of performed dosages exceeds said predetermined number value.

Advantageously, an HC dosing system is provided in which a variable change interval for the dosing unit is provided. According to one aspect of the invention, a function is provided for optimizing a change interval for the dosing unit, which function is based on the accumulated number of dosing performed on an HC dosing system since the last change of the dosing unit. After a change of the dosing unit, a variable indicating the accumulated number of dosing performed can be reset. The resetting of said variable can be performed manually by e.g. service personnel or an operator of the HC dosing system. The resetting of said variable can alternatively be performed automatically by means of a suitable configuration.

An advantage the dosing unit is optimized for with the present invention is that a replacement interval for vehicles where a cycle frequency of the dosing unit changes between different fixed values, which means that the dosing unit can be replaced or renovated at a suitable degree of wear or time.

An advantage of the present invention is that an additional cost associated with a premature change of the dosing unit caused by a fixed change interval for the dosing unit is reduced or minimized.

An advantage of the present invention is that a performance deterioration associated with a late change of the dosing unit is caused by a cycle frequency of the dosing unit e.g. set to a higher value can be reduced or minimized.

Advantageously, according to one aspect of the invention, it can be determined in an accurate and cost-effective manner whether the dosing unit should be replaced. The predetermined number value can be an application-specific value. According to one example, the predetermined number value is 100,000,000. According to another example, the predetermined value is 1,000,000. According to one embodiment, the predetermined number value may be within a range defined by [100,000,000, 200,000,000]. The predetermined number value can be selected on the basis of configuration and performance of the vent arrangement of the dosing unit.

By comparing the value representing the accumulated number of dosing performed at the dosing unit and the predetermined number value, it can be determined whether the dosing unit should be functionally degraded to such an extent that replacement should take place in the immediate vicinity, or that a replacement of the dosing unit can wait for a future planned service of the HC dosing system.

The method may further comprise the step of: - determining the need for a review of the valve arrangement of the dosing unit after said indication has been given. In this case, service personnel can obtain information about a degree of wear of the valve arrangement and decide whether the dosing unit should be replaced immediately or whether said replacement can wait until a planned service step.

The accumulated number of dosing performed can correspond to the number of changes between states and a valve arrangement, an open closed state of the dosing unit, which changes involve some wear of said valve arrangement. The wear can e.g. occur due to mechanical friction between a pin of the vent arrangement and a seat of the dosing unit.

Wear can occur at the pin or inlet for dosing fuel in the exhaust system.

According to one embodiment, the valve arrangement of the dosing unit has a pin which can be moved in a longitudinal direction between a first (closed) position and a second (open) position. In the closed position, the pin seals an inlet to the exhaust system and dosing of fuel is thereby prevented. In the open position, dosing of the fuel is permitted, which is effected by means of a pressurization of the fuel. Of course, other embodiments of the vent arrangement may be possible. According to an example, e.g. an inlet for dosing fuel of the exhaust system may be alternately sealable by means of a plate which is slidably arranged. In a number of different embodiments of valve arrangements, mechanical wear will occur over time, which wear is based on the accumulated number of performed dosages of fuel. This causes wear during intermittent dosing of fuel.

Said predetermined number value can be based on an empirically determined life expectancy of the valve arrangement of the dosing unit. In this case, a method is provided in which the expected life of the dosing unit can be determined in a fairly accurate manner. In this case, a change interval for the dosing unit can be optimized, which can lead to cost savings and positive effects in terms of performance of the HC dosing system.

Said predetermined number value can be based on results from practical tests of the valve arrangement of the dosing unit.

Said predetermined numerical value can be based on calculations according to a suitable model.

The fuel may be diesel or another hydrocarbon-based fuel. The method may further comprise the step of: - replacing or renovating said dosing unit after said indication has been given. Said replacement or renovation of the dosing unit can be done manually.

By providing an indication according to the invention, a user-friendly method according to the invention is achieved to the extent that service personnel can easily realize whether there is a need to replace or renovate the dosing unit.

An advantage of the innovative method is that an improved performance of the HC dosing system is achieved. Since a change interval for the dosing unit can be optimized, the risk of leakage due to wear of the valve arrangement will be minimized. This can cause unwanted oxidation of HC when it is not desired. In addition, the performance of the HC dosing system will be improved as a dosing image when dosing the fuel does not risk deteriorating due to excessive wear of the valve arrangement. further include activating a The procedure may be the step of indication configuration. This indicator configuration may be a lighting device for signaling that it is time to change the dosing unit of the HC-HC dosing system or in a vehicle cab of a vehicle incorporating said dosing system. The lighting device can be located at HC dosing systems. According to one example, a red light comes on when it has been determined that the accumulated number of dosing performed at the dosing unit exceeds the predetermined number value.

According to another example, an indicator configuration is activated in a control unit of the HC dosing system. According to one embodiment, this can take the form of a so-called flag in a computer program stored in the control unit, where said fl agga indicates that it is time to change the dosing unit of the HC dosing system.

This flag can e.g. HC- is detected by service personnel for the dosing system during a service or inspection thereof.

According to one embodiment, said accumulated number of dosing performed can be reset after a change of the dosing unit. This provides a user-friendly and inexpensive way to restart the innovative procedure after the replacement of the dosing unit has been performed.

According to one embodiment, the present invention can be applied to HC dosing systems where the cycle frequency of the dosing unit is variable.

In this case, a cycle frequency can be continuously changed in a suitable manner. According to one example, four subsequent cycles for the dosage unit may be 1 second, 2 seconds, 0.5 seconds, and 0.75 seconds. During each cycle, where appropriate, dosing with a certain duration of fuel can be performed. The control unit is hereby arranged to continuously determine a suitable prevailing cycle frequency of the dosing unit. The control unit is arranged to determine in a suitable manner a suitable prevailing cycle frequency of the dosing unit. Since the present invention is based on using the number of dosages of the dosage unit, the above objects are achieved independently of the cycle frequency of the dosage unit. In this way a versatile method is provided in an HC dosing system according to the invention.

According to one embodiment, the present invention can be applied to HC dosing systems where the cycle frequency of the dosing unit is variable insofar as different discrete steps of the cycle frequency are used. In this case, a cycle frequency can be changed between different levels in a suitable manner. In this case, a specific level of the cycle frequency can be used for a fairly long time, e.g. a day or a week or a number of months. According to one example, three different levels of cycle frequency for the dosage unit may be 1Hz, 5Hz, and 20Hz.

During each cycle for each level, where appropriate, fuel metering can be performed. Since the present invention is based on using the number of dosages of the dosage unit, the above objects are achieved independently of said discrete levels of the cycle frequency of the dosage unit. In this way a versatile method is provided in an HC dosing system according to the invention.

According to the HC dosing system for exhaust gas purification, where fuel is supplied to a feeding device, an aspect of the present invention is provided by means of which feeding device fuel is supplied to a dosing unit for batch supply of fuel by means of an HC dosing system. valve arrangement at a point of consumption of the HC dosing system comprises: - means for continuously determining by said dosing unit accumulated number of dosing performed; Means for continuously comparing said accumulated number of performed dosages with a predetermined number value, and - means for giving indication when said accumulated number of performed dosages exceeds said predetermined number value.

The HC dosing system may include or constitute a DPF system.

The HC dosing system may further comprise: - means for determining the need for review of the valve arrangement of the dosing unit after said indication has been delivered.

The accumulated number of dosing performed can correspond to the number of changes between states and a valve arrangement, an open closed state of the dosing unit, which changes involve some wear of said valve arrangement.

In the HC dosing system, said predetermined number value can be based on an empirically determined life expectancy of the valve arrangement of the dosing unit.

Said dosing unit can be arranged as a unit interchangeably.

Said valve arrangement is arranged as a unit interchangeably in said dosing unit.

The above objects are also achieved with a motor vehicle comprising the HC dosing system, according to one aspect of the invention. The motor vehicle can be anything from a truck, bus or car.

According to one aspect of the invention, there is provided a computer program of an HC dosing system for exhaust gas purification, wherein fuel is supplied to a feeding device, by means of which feeding device fuel is supplied to a dosing unit for batch supply of fuel by means of a valve arrangement at a consumption point of the HC dosing system , wherein said computer program comprises program code stored on a computer readable medium for causing an electronic control unit or another computer connected to the electronic control unit to perform the steps according to any one of claims 1-6.

According to one aspect of the invention, there is provided a computer program of an HC dosing system for exhaust gas purification, wherein fuel is supplied to a feeding device, by means of which feeding device fuel is supplied to a dosing unit for batch supply of fuel by means of a valve arrangement at a consumption point of the HC dosing system. to cause an electronic control unit or another computer connected to the electronic control unit to perform the steps according to any one of claims 1-6.

According to one aspect of the 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 computer program is run on an electronic control unit or another computer connected to the electronic control unit. .

The method according to the invention is easy to implement in existing motor vehicles. Software for said method in an HC dosing system for exhaust gas purification, where fuel is supplied to a feeding device, by means of which feeding device fuel is supplied to a dosing unit for batch supply of fuel by means of a valve arrangement at a consumption point of the HC dosing system according to the invention can be installed in a vehicle control unit. manufacture of the same. A buyer of the vehicle can thus be given the opportunity to choose the function of the procedure as an option. Alternatively, software including program code for performing the innovative procedure of an HC dosing system may be installed in a control unit of the vehicle when upgrading at a service station. In this case, the software can be loaded into a memory in the control unit. Implementing the innovative procedure is thus cost-effective. Software that includes program code for said procedure in an HC dosing system can be easily updated or replaced. Furthermore, different parts of the software comprising program code for said process in an HC dosing system can be replaced independently of each other. This modular configuration is advantageous from a maintenance perspective.

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 the 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 and incorporate within other further applications, modifications areas, which are within the scope of the invention. SUMMARY DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and further objects and advantages thereof, reference is now made to the following detailed description which is to be read in conjunction with the accompanying figures, in which like reference numerals refer to like parts in the various figures, and in which: 1 schematically illustrates a vehicle, according to an 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 3 schematically illustrates a dosing unit, according to an embodiment of the invention; Figure 4a schematically illustrates a flow chart of a method, according to an embodiment of the invention; Figure 4b schematically illustrates in further detail a flow chart of a method, according to an embodiment of the invention; and Figure 15 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 can be a heavy vehicle, such as a truck or a bus. The vehicle can alternatively be a car.

It should be noted that the invention is suitable for use in any HC dosing system and is not limited to the HC dosing system of motor vehicles. The innovative method and the innovative HC dosing system according to an aspect of the invention are well suited for other platforms which include an HC dosing system, such as e.g. watercraft. The watercraft can be of any kind, such as e.g. motorboats, ships, ferries or ships.

The innovative method and the innovative HC dosing system according to an aspect of the invention are also well suited for e.g. systems including industrial engines and / or motorized industrial robots.

The innovative method and the innovative HC dosing 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 innovative process and the innovative HC dosing system are well suited for an arbitrary engine system that includes an engine and an HC dosing system, such as e.g. at a locomotive or other platform. 10 15 20 25 30 14 The innovative method and the innovative HC dosing system are well suited for any system which includes a NOX generator and an HC dosing system.

The innovative method and the innovative device are well suited for an arbitrary system which includes an arbitrary system which generates exhaust gases with particles and a filter which stores particles, which particles are burned during a regeneration of said filters, in particular during an active regeneration of said filters. filter.

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

Here, the term "conduit" refers to a passage for holding and transporting a fluid, such as e.g. a fuel in liquid form. The pipe can be a pipe of any dimension. The conduit may consist of any suitable material, such as e.g. plastic, rubber or metal.

Herein, the term "fuel" refers to an agent used for the active regeneration of a particulate filter in an HC dosing system. Said fuel is according to one embodiment diesel. Of course, other types of hydrocarbon-based fuels can be used. Here, diesel is mentioned as an example of a fuel, but a person skilled in the art realizes that the innovative method and the innovative device can be realized for other types of fuels. The fuel of the HC dosing system can be any fuel, such as e.g. oil, such as e.g. lubricating oil, diesel or other hydrocarbon-based fuel, such as e.g. petrol, ethanol or methane, etc. According to one embodiment, the fuel may be in gaseous form. Although the term HC dosing system is used herein to indicate a particulate filter system, the invention is not limited to the use of a diesel particulate filter. On the contrary, other types of particle filters can be used according to the invention. One skilled in the art will recognize what kind of fuel is best suited for regenerating the selected particulate filter.

Referring to Figure 2, a subsystem 299 of the vehicle 100 is shown.

The subsystem 299 is arranged in the tractor 110. The subsystem 299 may form part of an HC dosing system. The subsystem 299 according to this example consists of a container 205 which is arranged to hold a fuel. The container 205 is arranged to contain a suitable amount of fuel and is further arranged to be able to be refilled if necessary. The container 205 may be an existing fuel tank of the vehicle.

A first line 271 is arranged to lead the fuel to a pump 230 from the container 205. The pump 230 may be any suitable pump. The pump 230 may be a diaphragm pump.

The pump 230 may be arranged to be operated by means of an electric motor (not shown).

The pump 230 is arranged to pump the fuel from the container 205 via the first line 271 and via a second line 272 supply said fuel to a dosing unit 250. The dosing unit 250 comprises an electrically controlled dosing valve, by means of which a flow of fuel added to the exhaust system can be controlled. The pump 230 is arranged to pressurize the fuel in the second line 272. The dosing unit 250 is arranged with a throttling unit, against which said pressure of the fuel is built up in the subsystem 299.

The dosage unit is described in further detail with reference to Figure 3.

The dosing unit 250 is arranged to supply said fuel to an exhaust system (see Figure 3) of the vehicle 100. More specifically, the dosing unit 250 is arranged to supply in a controlled manner a suitable amount of fuel to an exhaust system of the vehicle 100. According to this embodiment, a SCR catalyst (not shown) arranged downstream of a position of the exhaust system where supply of the fuel is effected. The amount of fuel supplied to the exhaust system is intended to be used to raise the temperature of the exhaust gases in the exhaust system.

The dosing unit 250 is arranged at e.g. an exhaust pipe arranged to direct exhaust gases from an internal combustion engine (not shown) of the vehicle 100 to a diesel particulate filter and an SCR catalyst.

A third line 273 is presently disposed between the metering unit 250 and the container 205. The third line 273 is arranged to return fuel not dosed by the metering unit 250 to the container 205.

With the dosing unit 250. In this way, the dosing unit 250 is cooled by means of a configuration which advantageously provides flow of the fuel as it is pumped through the dosing unit 250 from the pump 230 to the container 205.

The first control unit 200 is arranged for communication with the pump 230 via a link 292. The first control unit 200 is arranged to control operation of the pump 230 in order to e.g. regulate the flows of fuel within the subsystem 299.

The first control unit 200 is arranged to control an operating power of the pump 230 by controlling the electric motor thereby.

The first control unit 200 is arranged for communication with the dosing unit 250 via a link 291. The first control unit 200 is arranged to control operation of the dosing unit 250 in order to e.g. regulate the supply of fuel to the exhaust system of the vehicle 100. Dosing of fuel takes place on the basis of a certain cycle frequency. During each cycle, a metering valve of the metering unit may be open for a suitable period of time.

The first control unit 200 is arranged to continuously determine an accumulated number of performed doses of the dosing device 250. The first control unit 200 is arranged to compare said accumulated number of performed doses N with a predetermined number value TH. The first control unit 200 is arranged to determine whether said accumulated number of performed doses N exceeds the predetermined number value TH.

The first control unit 200 is arranged to give an indication when said accumulated number of performed doses N exceeds said predetermined number value TH. This can happen in different ways.

According to an example, the control unit can send an information signal to an instrument panel in the vehicle's cab. The information signal may include information that it is appropriate to change the dosage unit within a certain period of time. In this case, information can be displayed to a driver by means of display means, such as e.g. a display screen or lamp.

According to another example, the control unit may give an indication in the form of an error code being generated, which error code can be used to suitably indicate to a driver or service personnel that the dosing unit should be replaced or FGFIOVGFQS.

According to another example, the control unit can give an indication by generating a so-called flag in a memory of the controller. This flag can be detected by an operator performing an inspection of the vehicle, e.g. at a Service Event.

A second control unit 210 is arranged for communication with the first control unit 200 via a link 290. The second control unit 210 may be detachably 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 innovative method steps according to the invention. The second control unit 210 can be used to upload software to the first control unit 200, in particular software for performing the innovative 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 similar functions as the first control unit 200, such as e.g. to continuously determine by said dosing unit the accumulated number of performed dosages, continuously compare said accumulated number of performed dosages with a predetermined number value and give an indication when said accumulated number of performed dosages exceeds said predetermined number value. The innovative method can be performed by the first control unit 200 or the second control unit 210, or by both the first control unit 200 and the second control unit 210.

Referring to Figure 3, a subsystem including the dosing unit 250 is illustrated. Herein, the second line 272 and the third line 273 are shown.

According to this embodiment, the dosing unit 250 comprises a valve arrangement 350. The valve arrangement 350 may comprise an electronic control card, which e.g. is arranged to handle the communication with the control unit 200. The 200 is the valve arrangement 350 via the link 291. The valve arrangement 350 is further pin 360. Pin 360 is the dosing unit 250. Pin 360 is arranged to alternately close and open the first control unit arranged for communication with a slidably arranged in an inlet to an exhaust pipe 310 of the HC dosing system, which exhaust pipe 310 is arranged to direct exhaust gases from an engine to an environment of the HC dosing system. The valve arrangement 350 is arranged to, depending on signals received from the first control unit 200 via the link 291, alternately displace the pin 360 back and forth in a longitudinal direction thereof to effect dosing of the fuel into the exhaust pipe 310.

The valve arrangement 350 may be in a closed position Closed where the pin 360 is in such a position that dosing is not possible, i.e. pin 360 closes the inlet to the exhaust system 10 15 20 25 30 19. The valve arrangement 350 may be in an open position Open where the pin 360 is in such a position that dosing is effected, i.e. the pin 360 does not close the inlet to the exhaust system and dosing is accomplished by the pressure that the pump 230 has built up in the second line 272.

According to the invention, the accumulated number of dosing performed is determined in order to be able to determine whether it is time to replace the dosing unit due to wear. A dosage counts as a movement of the pin 360 from the Closed position to the Open position and back to the Closed position. In this case, fuel is dosed during the time interval that the pin does not close the inlet to the exhaust pipe 310.

According to one aspect of the invention, a variable change interval is provided for the dosing unit 250 to compensate in a flexible manner for wear that occurs during the alternating movements of the pin 360.

It should be noted that the invention is not limited to the specific embodiment which comprises said valve arrangement including the pin 360 for providing dosing of fuel. The invention is applicable to a number of different types of valve arrangements where wear due to e.g. friction affects the performance of the valve arrangement overtime. Wear can occur at a seat of the valve arrangement. Wear can be caused by a flow of the fuel under high pressure.

Figure 4a schematically illustrates a flow chart of a process in an HC dosing system for exhaust gas purification, where fuel is supplied to a supply device, by means of which supply device fuel is supplied to a dosing unit for batch supply of fuel by a consumption point of the HC dosing system, according to an embodiment of valve arrangement the invention. The method comprises a first method step s401. The step s401 includes the steps of: - continuously determining by said dosing unit the accumulated number of dosing performed; - continuously comparing said accumulated number of performed dosages with a predetermined number value, and - giving an indication when said accumulated number of performed dosages exceeds said predetermined number value. After step s401, the process is terminated.

Figure 4b schematically illustrates a flow chart of a process in an HC dosing system for exhaust gas purification, where fuel is supplied to a supply device, by means of which supply device fuel is supplied to a dosing unit for batch supply of fuel by a valve arrangement at a consumption point of the HC dosing system, according to an embodiment of the invention.

The method includes a first method step s410. Method step s410 includes the step of determining by the dosing unit 250 the accumulated number of performed doses N. This can be done by continuously counting a variable N in a memory of the first control unit 200. After the method step s410 a subsequent method step s420 is performed.

The method step s420 comprises the step of comparing said accumulated number of performed doses N with a predetermined number value TH. In this case, a fast and robust method is provided for determining whether a change of the dosing unit 250 is desirable. In this case, a method is provided for determining whether a change of the dosing unit 250 is required, which first control unit 200 is arranged to perform the method step s420. After procedure advantageously requires small computational resources. The process step s420 is performed a subsequent process step s430.

The method step s430 comprises the step of determining whether said accumulated number of performed doses N exceeds the predetermined number value TH. The first control unit 200 is arranged to perform the method step s430. After the process step s430, a subsequent process step s440 is performed.

The method step s440 includes the step of giving an indication when said accumulated number of performed dosages exceeds said predetermined number value. Said indication can be performed in a suitable manner. Said indication may be provided as an information signal from the first control unit 200 to suitable means, e.g. a display screen in the cab of the vehicle. Said indication can be given as audio and / or visual feedback to an operator of the vehicle. Alternatively, said indication can be given as a so-called flagging of the control unit, which flagging can be detected at e.g. a service opportunity.

After the process step s440, a subsequent process step s450 is performed.

The method step s450 includes the step of determining the need for review of the valve arrangement of the dosing unit after said indication has been given.

Said need for review may be required fairly immediately or within a predefined time interval, such as e.g. a day, week or month. After the process step s450, a subsequent process step s460 is performed.

Method step s460 includes the step of replacing or renovating said dosage unit after said indication has been given. Method step s460 may include the step of manually replacing or renovating said dosage unit after said indication has been given. After completing the dosing unit 250 to or after renovating the existing dosing unit, the number value N of a corresponding new / unused dosing unit, representing the accumulated number of performed dosing units, can be reset.

This can e.g. is performed by actuating the first control unit 200. After resetting the number value, enumeration thereof can be started again to optimize a change interval for the new or renovated dosing unit 250. After the process step s460, the process is terminated. Referring to Figure 5, 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, 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 which comprises routines for continuously determining by the dosing unit 250 the accumulated number of performed doses N. The computer program P comprises routines for continuously comparing said accumulated number of performed doses N with a predetermined number value TH. The computer program P includes routines for giving an indication when said accumulated number of performed dosages N exceeds said predetermined number value TH. The program P includes routines for determining the need for review of the valve arrangement 350 of the dosing unit after said indication has been given. 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 may 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 10 15 is intended to communicate with the data processing unit 510 via a data bus 512. data bus 511. the data processing unit 510 via a data bus 514. To the data port 599, e.g. links 290, 291 and 292 are connected (see Figure 2 and Figure 3).

The read / write memory 550 is arranged to communicate with When data is received on the data port 599, it is temporarily stored in the second memory part 540. The data processing unit 510 is arranged to perform code execution in a manner described above. The device 500 is arranged to continuously determine an accumulated number of performed doses N of the dosing unit 250. Said accumulated number of performed doses N may be stored in a memory of the device 500, e.g. memory 550 or memory 560. Said predetermined number value TH may also be stored in a memory of the device 500, e.g. memory 550 or memory 560. Said predetermined numerical value can be updated where applicable. Said predetermined number value can be reset after a change or renovation of the dosing unit 250 has been performed.

Parts of the methods described herein may be performed by the device 500 by means of the data processing unit 510 running the program stored in the memory 560 or the 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 (17)

10 15 20 25 30 24 PATENT REQUIREMENTS A method of an HC dosing system for exhaust gas purification, wherein fuel is supplied to a supply device (230), by means of which supply device (230) fuel is supplied to a dosing unit (250) for batch supply of fuel by means of a valve arrangement (350, 360) at a consumption point of HC dosing system, characterized by the steps of: - continuously determining (s410) by said dosing unit (250) the accumulated number of dosing performed (N); - continuously comparing (s420, s430) said accumulated number of performed doses (N) with a predetermined number value (TH), and - giving indication (s440) when said accumulated number of performed doses (N) exceeds said predetermined number value (TH). The method of claim 1, further comprising the step of: - determining the need for review (450) of the valve assembly (350, 360) of the dosage unit after said indication has been delivered. A method according to claim 1 or 2, wherein the accumulated number of performed doses (N) corresponds to the number of changes between an open state (Open) and a closed state (Closed) of the valve arrangement (350, 360) of the dosing unit. A method according to any one of claims 1-3, wherein said predetermined number value (TH) is based on a determined expected life of the dosing unit valve arrangement (350, 360). A method according to any one of the preceding claims, wherein said fuel is diesel. A method according to any one of the preceding claims, further comprising the step of: - replacing or renovating (s460) said dosing unit (250) after said indication has been delivered. A HC dosing system for exhaust gas purification, wherein fuel is supplied to a supply device (230), by means of which supply device (230) fuel is supplied to a dosing unit (250) for batch supply of fuel by means of one (350, 360) at a consumption point of the HC dosing system, characterized by - means (200; 210; 500) dosing unit accumulated number of performed dosing (N); valve arrangements for continuously determining said means (200; 210; 500) for continuously comparing said accumulated number of doses performed (N) with a predetermined number value (TH), and - means (200; 210; 500) for giving indication. when said accumulated number of performed dosages (N) exceeds said predetermined number value (TH). The HC dosing system according to claim 7, further comprising: - means (200; 210; 500) for the valve arrangement of the dosing unit (350, 360) after said indication to determine the need for review of delivered. HC dosing system according to claim 7 or 8, wherein the accumulated number of dosing performed (N) corresponds to the number of changes between an open state (Open) and a closed state (Closed) of the valve arrangement of the dosing unit (350, 360). The HC dosing system of any of claims 7-9, wherein said predetermined (TH) determined dosage unit valve arrangement (350, 360). numerical value is based on the expected life of An HC dosing system according to any one of claims 7-10, wherein said fuel is diesel. 10 15 20 25 26 HC dosing system according to any one of claims 7-11, wherein said dosing unit (250) is arranged as a unit interchangeably. HC dosing system according to any one of claims 7-12, wherein said valve arrangement (350, 360) is arranged as a unit interchangeably in said dosing unit (250). A motor vehicle (100; 110) comprising an HC dosing system according to any one of claims 7-13. A motor vehicle (100; 110) according to claim 14, wherein the motor vehicle is something of a truck, bus or passenger car. Computer program (P) in HC dosing system for exhaust gas purification, wherein said computer program (P) comprises program code stored on a computer readable medium for causing an electronic control unit (200; 500) or another computer (210; 500 ) connected to the electronic control unit (200; 500) to perform the steps according to any one of claims 1-6. 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 computer program is run on an electronic control unit (200; 500) or another computer (210; 500) connected to the electronic control unit (200; 500).