SE1050647A1 - Device comprising an HC dosing system and a method of an HC dosing system - Google Patents

Abstract

SUMMARY The invention relates to a method of HC dosing system pre-exhaust purification, including a dosing unit (250) for fuel, comprising the steps of determining a need to, after shutting off an exhaust stream, cooling said dosing unit for fuel by means of fuel, and the step of predicting a temperature advance of at least a portion of said HC dosing system as a basis for determining said need. The invention also relates to a computer program product comprising program code (P) for a computer (200; 210) for implementing a method according to the invention. The invention also relates to a device of an HC dosing system and a motor vehicle equipped with the device. Figure 2 for publication

Description

the pressure at small or no dosing amounts, the system also consists of a return hose which is arranged from a pressure side of the system back to According to the dosing unit by means of said diesel which flows from the container when cooled. In this configuration, it is possible to cool the container via the pump and the dosing unit back to the container. In this way an active cooling of the dosing unit is provided. The return flow from the dosing valve to the container is today substantially constant.

Since the dosing unit is currently arranged at the exhaust system of the vehicle, which exhaust system during operation of the vehicle is heated depending on e.g. load on the engine, the dosing valve risks overheating. Overheating of the dosing unit may result in degradation of the same consideration functionality, which may result in a degraded performance thereof.

The dosing unit today comprises electrical components, some of which include a circuit board. Said circuit boards can e.g. be provided for controlling the dosing of diesel to the exhaust system of the vehicle. These electrical components are sensitive to high temperatures for several reasons. Excessive temperatures of the dosing unit can result in degradation of the electrical components, which can lead to costly repairs at a service workshop. Furthermore, diesel present in the dosing unit can at least partially change to solid form at too high temperatures, which can lead to clogging of the dosing unit. According to one example, said diesel in the dosing unit undergoes pyrolysis, said diesel being at least partially converted to coke. Thus, at least a part of said can cook. diesel It is therefore of the utmost importance that the temperature of the dosing unit of the DPF system does not exceed a critical temperature.

Cooling of the dosing unit of a DPF system in vehicles today takes place continuously during ordinary operation of the vehicle as said diesel is circulated within the DPF system in the manner indicated above. To some extent, cooling of the dosing unit during operation of the vehicle today works satisfactorily.

However, there is always a need to improve the performance of existing subsystems, DPF systems, competition point of view. for example in vehicles, not least seen from a During and after operation of the vehicle, there is a stored amount of thermal energy in mainly the exhaust system caused by said operation. This thermal energy can be led to the dosing unit from e.g. a muffler and the particle filter of the dosing unit, which can be heated to a temperature exceeding a critical value thereof.

When switching off the vehicle and thus after switching off the exhaust flow in the exhaust system, the dosing unit for diesel is cooled by means of said diesel in the same way as during ordinary operation for a predetermined time, such as e.g. 30 minutes.

This action is associated with certain disadvantages. As an example, a relatively large amount of energy is required to drive the pump in the DPF system after switching off the vehicle. In the event that a vehicle battery drives the pump of the DPF system, this can be discharged or reach a relatively low degree of charge.

Another disadvantage of cooling the dosing unit in the same way as during ordinary operation is that the pump of the DPF system produces disturbing noise, which e.g. a driver of the vehicle may find it annoying, especially in the event that the driver is to sleep in the cab after a driving session, or where the driver is in the immediate vicinity of the vehicle.

Thus, there is a need to improve the current cooling process of the dosing unit in the HC dosing system after the vehicle has been switched off in order to reduce or eliminate the above-mentioned disadvantages.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new and advantageous method for improving the performance of an HC dosing system.

Another object of the invention is to provide a new and advantageous device and a new and advantageous computer program for improving the performance of an HC dosing system.

An object of the present invention is to provide a new and advantageous method for effecting cooling of a dosing unit of an HC dosing system after switching off an exhaust gas flow therein.

Another object of the invention is to provide a new and advantageous device and a new and advantageous computer program for effecting cooling of a dosing unit of an HC dosing system after shutting off an exhaust gas flow therein.

A further object of the invention is to provide a method, an apparatus and a computer program for reducing the risk of a dosing unit in an HC dosing system overheating after shutting off an exhaust gas flow in the HC dosing system.

A further object of the invention is to provide an alternative method, an alternative device and an alternative computer program for reducing the risk of a dosing unit in an HC dosing system overheating after switching off an exhaust gas flow in the HC dosing system.

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

According to one aspect of the invention, there is provided a method of HC dosing system for exhaust gas purification, including a dosing unit for fuel, comprising the steps of: - determining a need to, after shutting off an exhaust stream, cooling said dosing unit for fuel by means of fuel, and - predicting a temperature course of at least a part of said HC dosing system as a basis for determining said needs.

By providing a calculation model which is arranged to calculate a future maximum temperature of the dosing unit which will be achieved, given stored energy of different parts of the HC dosing system, at the shut-off of the exhaust gas flow a reduced influence of the HC dosing system can be achieved. The calculation model is arranged to sample temperatures of different parts of the HC dosing system in the immediate time before and / or after switching off the exhaust gas flow and can on this basis predict whether the dosing unit will reach temperatures that are too high, at which temperatures the dosing unit could be damaged. In the event that it is determined that an excessively high temperature of the dosing unit is likely to be reached, cooling of the fuel dosing unit by means of fuel can be maintained at any suitable level. In the event that it is determined that an excessively high temperature of the dosing unit is not likely to be reached, cooling of the fuel dosing unit by means of fuel can be switched off automatically. In this case, the number of occasions involving continued cooling of the dosing unit for fuel by means of fuel when the exhaust gas flow is switched off can be reduced, which is advantageous from several aspects. For example. unnecessary use of electrical energy to drive a said fuel supply device in the HC dosing system is avoided.

The method may further comprise the step of predicting whether a predetermined temperature of the dosing unit will be reached after said shut-off of exhaust gas flow. By predicting a temperature advance of the dosing unit, operation of the fuel supply device in the HC dosing system can be controlled in an optimal way, taking into account the use of electrical energy. By predicting a temperature advance of the dosing unit, and automatically determining whether continued operation of the feeding device should cease, unnecessary cooling of the dosing unit can be avoided.

Said predetermined temperature may be a functionally critical temperature for the dosing unit. Said function-critical temperature is a temperature at which e.g. electronic components of the dosing unit may be damaged to the extent that its functionality is degraded or eliminated. By setting said predetermined temperature to a suitable value, a robust method is provided to reduce the risk of a dosing unit in an HC dosing system overheating after shutting off an exhaust gas flow in the HC dosing system.

Said at least a portion of said HC dosing system may comprise something of a particulate filter, e.g. a DPF, a muffler, the dosing unit advantageously to the temperature advance of the dosing unit. In cases such as a temperature rise and the fuel. In particular, it is a predictor of other components of the HC dosing system, such as e.g. the particle filter temperature up for the dosing unit on the basis thereof. Said prediction or the muffler, it can be modeled a predicted of the temperature course of said at least a part of said HC dosing system thus enables indirect determination of a future temperature of the dosing unit. In particular, an indirect determination of a future maximum temperature of the dosing unit is made possible. Said prediction of the temperature course may include consideration of reheating effects of at least a part of the HC dosing system. Depending on how the HC dosing system has been operated, different amounts of thermal energy may be integrated in different parts of the HC dosing system. This thermal energy can be led to the dosing unit even after switching off the exhaust gas flow.

According to one aspect of the invention, reheating effects are taken into account when modeling a temperature course of the dosing unit.

The method may further comprise the step of predicting said temperature course of at least a part of said HC dosing system by means of a calculation model including a predetermined parameter configuration.

The parameter configuration can be any suitable parameter configuration, including e.g. a prevailing temperature of the particulate filter and / or a prevailing temperature of the muffler and / or a prevailing temperature of the fuel or dosing unit.

The step of determining said need may be performed before said shutdown of exhaust flow, or the step of determining said need may be performed after said shutdown of exhaust flow. By determining said need before shutting off the exhaust flow, a decision to interrupt cooling of the dosing unit can be made earlier than if the step of determining said need is performed after said shutting off of exhaust flow. By determining the said need after shutting off the exhaust flow, a decision to interrupt cooling of the dosing unit can be made on the basis of a more updated basis compared to if said need is determined before shutting off the exhaust flow.

Said fuel may be diesel or other hydrocarbon-based fuel.

The procedure is easy to implement in existing motor vehicles. Software in an HC dosing system for exhaust gas purification according to the invention can be installed in a control unit of the vehicle in the manufacture thereof. 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 process of an HC dosing system for exhaust gas purification 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. implementation of the innovative procedure is thus cost-effective, especially since no additional components or subsystems need to be installed in the vehicle.

The required hardware is already present in the vehicle today.

The invention thus provides a cost-effective solution to the above problems.

Software comprising program code for determining a need to, after shutting off an exhaust flow, cool a dosing unit for fuel by means of fuel, and predict a temperature course of at least a part of said HC dosing system as a basis for determining said need, according to one aspect of the invention, can be easily updated or replaced. Furthermore, different parts of the software that include program code to perform the innovative procedure can be replaced independently. This modular configuration is advantageous from a maintenance perspective.

According to one aspect of the invention, there is provided an apparatus comprising an HC dosing system for exhaust gas purification, including a dosing unit for fuel. The device comprises means for determining a need to, after switching off an exhaust gas flow, cool said dosing unit for fuel by means of fuel, and means for predicting a temperature course of at least a part of said HC dosing system as a basis for determining said needs.

The device may further comprise means for predicting whether a predetermined temperature of the dosing unit will be reached after said shut-off of exhaust gas flow. Said predetermined temperature may be a functionally critical temperature for the dosing unit.

Said at least a portion of said HC dosing system may comprise something of a particulate filter, a muffler, the dosing unit or the fuel.

Said prediction of temperature course of said at least a part of said HC dosing system can enable indirect determination of a future temperature of the dosing unit.

Said prediction of the temperature course may include consideration of reheating effects of at least a part of the HC dosing system.

The device may further comprise means for predicting said temperature course of at least a part of said HC dosing system by means of a predetermined calculation model including a parameter configuration.

The means for determining said need may be arranged to determine said need before said shutdown of exhaust flow, or where the means for determining said need are arranged to determine said need after said shutdown of exhaust flow.

The above objects are also achieved with a motor vehicle incorporating the features of the device including an HC dosing system.

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

An advantage of the present invention is that the time as a control unit of the vehicle does not have to be activated as often or as long as before to monitor and control the fuel supply device.

According to one aspect of the invention there is provided an arbitrary platform comprising a device with an HC dosing system, such as e.g. a watercraft. The watercraft can be of any kind, such as e.g. a motorboat, a ship, a ferry or a ship.

According to one aspect of the invention, there is provided a computer program of HC exhaust gas purification system, including a fuel metering unit, said computer program comprising program code stored on a computer readable medium to cause an electronic control unit or another computer connected to the electronic the control unit to perform the steps according to any one of claims 1-9.

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 1-9, when said computer program 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 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 drawings 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 subsystem of the vehicle shown in Figure 1, 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 illustrating a computer, Figure 5 schematically 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 with an engine 150 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.

It should be noted that the invention is suitable for use in any suitable HC dosing system and is not limited to DPF systems in motor vehicles. The innovative method and the innovative device according to an aspect of the invention are well suited for platforms which include an HC dosing 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 innovative method and the innovative device according to an aspect of the invention are also well suited for e.g. systems including industrial motors and / or motor-driven industrial robots and / or a stationary motor. The innovative method and the innovative device 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 method and the innovative device are well suited for an arbitrary engine system which includes an engine and an HC dosing system, such as e.g. at a locomotive or other platform.

The innovative method and device are well suited for an arbitrary system that includes a particulate generator (eg, an internal combustion engine) and an HC dosing system.

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 "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, with requirements such as e.g. adequate adjustments, adjustments to the boiling temperature of selected fuels, in control algorithms for executing software code in accordance with the innovative procedure. 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 contain 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 can hold e.g. 200 or 1500 liters of fuel.

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 comprising at least one filter. The pump 230 is arranged to be driven by means of an electric motor. 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 provided with a throttling unit, against which said pressure of the fuel is built up in the subsystem 299.

Dosing unit 250 is arranged to supply said fuel to a 100. Dosing unit 250 is arranged to supply in a controlled manner a suitable amount of exhaust system (not shown) to the vehicle. More specifically, fuel is to an exhaust system of the vehicle 100. According to this embodiment, a particulate filter (not shown), e.g. a DPF, arranged downstream of a position of the exhaust system where the supply of fuel is provided. The amount of fuel 14 supplied to the exhaust system is intended to be used in a conventional manner in the HC dosing system for active regeneration of the particulate filter.

The dosing unit 250 is arranged at e.g. an exhaust pipe arranged to direct exhaust gases from the internal combustion engine 150 of the vehicle 100 to said particulate filter. The dosing unit 250 is arranged in thermal contact with the exhaust system of the vehicle 100. This means that thermal energy is integrated in e.g. an exhaust pipe, muffler, particulate filter and SCR catalyst can then be led to the dosing unit 250.

The dosing unit 250 comprises an electronic control card, which is 200.

The dosing unit 250 also comprises plastic and / or rubber components, arranged to handle communication with a control unit which may melt or be otherwise adversely affected at excessive temperatures.

The dosing unit 250 is sensitive to temperatures above a certain temperature value, such as e.g. 120 degrees Celsius. Since e.g. exhaust pipe, this temperature value there is a risk that the dosing unit 250 may overheat the muffler and the particulate filter of the vehicle 100 exceeds during operation of the vehicle or after operation of the vehicle unless cooling thereof is achieved.

A third conduit 273 is provided between the metering unit 250 and the container 205. The third conduit 273 is arranged to return a certain amount of the fuel supplied to the metering valve 250 to the container 205. With this configuration advantageous cooling of the metering unit 250 is provided. the metering unit 250 is cooled by a flow of the fuel as it is pumped through the metering unit 250 from the pump 230 to the container 205.

A first control unit 200 is communication with a temperature sensor 220 via a link 293. The temperature sensor 220 is arranged to detect a prevailing temperature of the fuel where the sensor is mounted.

According to this embodiment, the temperature sensor 220 is arranged in the container 205.

The temperature sensor 220 is arranged to continuously send signals to the first control unit 200 including information about a prevailing temperature of the fuel.

According to a 220 dosing unit 250 for detecting a prevailing temperature there. According to an alternative, the temperature sensor is arranged in another embodiment, the temperature sensor 220 is arranged at the particle filter of the HC dosing system to detect a prevailing temperature there. Any number of temperature sensors may be provided in the subsystem 299 to detect a prevailing temperature therewith. The temperature sensor 220 or the temperature sensors 220 are arranged (e) to detect a prevailing temperature at a suitable position within the subsystem 299, which detected temperature can form the basis for controlling operation of the pump 230 for cooling the dosing unit by said flow of fuel.

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. regulating a pressure in the line 272. Thereby, a return flow of the fuel from the dosing unit 250 to the container 205 can be described as a function of a pressure of the fuel upstream of the dosing unit 250.

The first control unit 200 is arranged to control a prevailing temperature of the dosing unit by controlling operation of the pump 230.

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. regulating the supply of fuel to the exhaust system of the vehicle 100. The first control unit 200 16 is arranged to control the operation of the dosing unit 250 in order to e.g. regulate the re-supply of fuel to the tank 205.

According to one embodiment, the first control unit 200 is arranged to control operation of the pump 230 on the basis of the signals received from the temperature sensor, including information on a prevailing temperature of the fuel at any suitable position of the HC metering system. embodiment arranged to, on the basis of the received signals comprising a prevailing temperature of the fuel at the area of the temperature sensor 220, intermittently control operation of the pump 230 with reduced power compared to ordinary operation after shutting off an exhaust gas flow from the engine.

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. calculating a value for future maximum temperature of the dosing unit on the basis of the received signals comprising a prevailing temperature of the fuel and controlling operation of the pump 230 in any suitable manner on the basis of the calculated temperature value. The second control unit 210 may be arranged to determine a need to, after switching off an exhaust flow, cool a dosing unit for fuel by means of fuel, and to predict a temperature course of at least a part of said HC dosing system as a basis for determining said needs. It should be noted that the innovative procedure 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.

According to the embodiment schematically illustrated with reference to Figure 2, the first control unit 200 is arranged to control operation of the pump 230 with reduced power compared to ordinary operation after shutting off an exhaust flow from the engine in such a way that, where applicable, an amount required electrical energy to cool the dosing unit 250 to a safety-critical temperature is reduced compared to the prior art.

According to this embodiment, a source of compressed air 260 is arranged to supply pressurized air to the dosing unit 250 via a line 261. The dosing unit 250 is arranged to use said supplied pressurized air to further atomize the fuel being dosed. The compressed air can also be used to at least partially drive the dosing unit to dose said fuel into the exhaust duct. The compressed air can also be used to, where applicable, blow out e.g. the dosage unit 250 with respect to fuel contained therein. This can be done during operation of the motor 150, or after the motor 150 has been switched off.

According to one embodiment, the container 205 may be the vehicle's fuel tank, with parts of the vehicle's existing fuel system being used in accordance with the present invention. According to another example, the container may be a separate container, i.e. not the same container as the vehicle's fuel tank.

According to one embodiment, the dosing unit 250 is arranged directly at an exhaust duct of the HC dosing system. According to another example, the dosing unit 250 is provided with a passive nozzle presently provided through said exhaust duct for dosing said fuel directly into the exhaust duct. According to one embodiment, said pump 230 is the same pump that normally generates fuel pressure for an injection system of the engine 150. According to another example, said pump 230 is a separate pump, i.e. not the same pump that normally generates the fuel pressure to the injection system.

According to one example, a precatalyst and / or oxidation catalyst is mounted in series with the particulate filter. In this case, said precatalyst and / or oxidation catalyst are arranged upstream of said particle filter.

Figure 3 schematically illustrates a subsystem 399 of the vehicle 100.

Subsystem 399 includes certain components described above with reference to Figure 2, such as e.g. the first control unit 200, the second control unit 210 and the temperature sensor 220 for detecting a prevailing temperature of the fuel in the container 205.

The subsystem 399 includes a temperature sensor 310 arranged to measure a prevailing temperature of exhaust gases in an exhaust system upstream of the particulate filter. The temperature sensor 310 is arranged for communication with the first control unit via a link 311. The temperature sensor 310 is arranged to continuously send signals including information about a prevailing temperature of the exhaust stream to the first control unit 200 via the link 311. According to one embodiment, the first control unit 200 is arranged to estimating a prevailing temperature of the particulate filter on the basis of the received signals including information on a prevailing temperature of the exhaust stream.

The subsystem 399 includes a temperature sensor 320 which is arranged to measure a prevailing temperature of the particulate filter. The temperature sensor 320 is arranged for communication with the first control unit via a link 321.

The temperature sensor 320 is arranged to continuously send signals 19 including information about a prevailing temperature of the particle filter to the first control unit 200 via the link 321.

The subsystem 399 includes a temperature sensor 330 arranged to measure a prevailing temperature of the metering unit 250. The temperature sensor 330 is arranged for communication with the first control unit via a link 331. The temperature sensor 330 is arranged to continuously send signals including information about a prevailing temperature of the metering unit 250 to the first control unit 200 via the link 331.

The subsystem 399 includes a flow sensor 340 which is arranged to measure a prevailing flow of the fuel in the HC dosing system. The flow sensor 340 of the HC downstream can be arranged at any suitable position 273 the dosing unit 250. The flow sensor 340 is arranged for the communication dosing system, such as e.g. at the line with the first control unit via a link 341. The flow sensor 340 is arranged to continuously send signals including information about a prevailing flow of the fuel to the first control unit 200 via the link 341.

The signals sent by the sensors 310, 320, 330, 340 and 220, respectively, can be used by the first control unit to model a temperature profile of the dosing unit 250 according to an aspect of the invention. According to one embodiment, the first control unit 200 is arranged to model a temperature variation of the dosing unit 250 on the basis of the information of at least one of the signals received from the sensors 310, 320, 330, 340 and 220, respectively.

Figure 4a schematically illustrates a flow chart of a process in HC exhaust gas purification systems, including a fuel metering unit, according to an embodiment of the invention. The method comprises a first method step s401. Step s401 includes the step of determining a need to, after shutting off an exhaust flow, cooling said dosing unit for fuel by means of fuel, and the step of predicting a temperature course of at least a part of said HC dosing system as a basis for determining said need. After step s401, the process is terminated.

Figure 4b schematically illustrates a flow chart of a process in HC exhaust gas purification systems, including a fuel metering unit, according to an embodiment of the invention.

The method includes a first method step s410. Method step s410 includes the step of shutting off an exhaust gas flow from an internal combustion engine of the vehicle 100. At this time, the metering unit 250 is cooled in an ordinary manner, i.e. with the operating power of the pump 230 needed to maintain substantially the same cooling flow of the dosing unit as in ordinary operation.

Shut-off of the exhaust gas flow is effected by shutting down the engine of the vehicle 100. After the process step s410, a subsequent process step s415 is performed.

Method step s415 includes the step of calculating a future temperature course of the dosing unit 250 by means of a calculation model stored in the first control unit 200 or the second control unit 210.

The calculation of the temperature course can take place on the basis of one or a number of arbitrary parameters, such as e.g. a prevailing temperature of the particulate filter of the vehicle, a prevailing temperature of the fuel, a flow of the fuel in the HC dosing system, a prevailing temperature of a muffler of the vehicle, a prevailing temperature of the dosing unit 250, temperature of an exhaust gas flow before switching it off and / or a parameter associated with estimated engine load for a certain period of time before shutting off said exhaust flow. The calculation model is arranged to calculate a prevailing amount of energy stored in different parts of the HC dosing system in order to calculate on the basis thereof and thus predict a temperature course of the dosing valve 250 as a basis for determining a need to cool the dosing unit 250. By calculating a future temperature course 21 of the dosing unit 250, it can also be determined what maximum temperature the dosing unit 250 can reach in the event that cooling thereof does not continue or is interrupted after the shut-off of the exhaust gas flow. By determining a modeled value for a maximum future temperature of the dosing unit 250, operation of the pump 230 can be optimally controlled in After s415 procedure step s420. basis thereof. the process step is performed a subsequent Process step s420 includes the step of evaluating whether there is a continuing need to cool the dosing unit by means of a flow of the fuel in the HC dosing system. The step of determining whether there is a need to continue said cooling can take place on the basis of the determined modeled value for maximum future temperature of the dosing unit 250. According to an example, it is determined whether a continued cooling need exists on the basis of the signals from at least one of the sensor 220, the sensor 310, the sensor 320, the sensor 330, the sensor 340, which signals include information in accordance with what has been described above with reference to Figure 3. If there is no further cooling need, the process is terminated. If there is a continued cooling demand, a subsequent procedure step s430 is performed.

The method step s430 includes the step of influencing the operation of the pump 230 in such a way that the pump is operated intermittently and / or with reduced operating power compared to ordinary operation. According to one embodiment, the pump 230 is operated intermittently with a predetermined interval configuration. According to one embodiment, the pump 230 is operated intermittently with an operating power corresponding to ordinary operation. According to one embodiment, the pump 230 is operated intermittently with a reduced operating power compared to an operating power used to maintain a cooling flow of the dosing unit 250 during ordinary operation. After the process step s430, a subsequent process step s440 is performed.

Process step s440 includes the step of evaluating whether there is a continuing need to continue cooling the metering unit by means of a flow of the fuel in the HC metering system. The step of determining whether there is a need to continue said cooling can take place on the basis of an updated modeled value for maximum future temperature of the dosing unit 250.

According to one embodiment, the calculation model is arranged to continuously update a determined modeled value for the future maximum temperature of the dosing unit 250. Calculation of an updated value for said maximum temperature can be performed in substantially the same way as described e.g. with reference to procedure step s415. According to one example, it is determined whether a continued cooling demand exists on the basis of the signals from at least one of the sensor 220, the sensor 310, the sensor 320, the sensor 330, the sensor 340, which signals include information as described above with reference to Figure 3. it is determined that there is no continued cooling requirement, the procedure is terminated. If it is determined that there is a continued need for cooling, operation of the pump 230 continues in an arbitrary manner to ensure efficient cooling of the dosing unit 250. Eg. the pump 230 can continue to be operated intermittently, possibly even with reduced operating power compared to ordinary operation.

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-usable 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 200. 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 determining a need to, after switching off an exhaust gas flow, cool a dosing unit for 23 fuel by means of fuel, and to predict a temperature course of at least a part of said HC dosing system as a basis for determining said needs, according to the innovative procedure. The program P includes routines for predicting whether a predetermined temperature of the dosing unit will be reached after said shut-off of exhaust gas flow. 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. the data processing unit 510 via a data bus 514. To the data port 599, e.g. links 311, 321, 331, 341, 293 and 290 are connected (see 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. When the received input data has been temporarily stored, the data processing unit 510 is prepared to perform code execution in a manner described above. According to one embodiment, signals received at the data port 599 include information of a prevailing temperature of a particulate filter of the vehicle 100. According to one embodiment, signals received at the data port 599 include information of a prevailing temperature of the fuel in the HC dosing system. According to one embodiment, signals received at the data port 599 include information about a prevailing flow of the fuel, e.g. in line 273. According to one embodiment, signals received at the data port 599 include information about a prevailing temperature of the dosing unit 24 250 of the HC dosing system. According to one embodiment, signals received at the data port 599 include information about a prevailing temperature of an exhaust gas i in the exhaust system of the vehicle 100.

The received signals on the data port 599 can be used by the device 500 to determine, by means of a calculation model stored in the device 500, a need to, after switching off an exhaust flow, cool a dosing unit for fuel by means of fuel, and predict a temperature course of at least a part of said HC dosing system as a basis for determining said needs.

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 (22)

10 15 20 25 30 25 PATENT REQUIREMENTS A method of HC dosing system for exhaust gas purification, comprising a dosing unit (250) for fuel, comprising the steps of: - determining a need to, after switching off an exhaust flow, cool said dosing unit (250) for fuel by means of fuel, characterized by the step to: - predict a temperature course of at least a part of said HC dosing system as a basis for determining said needs. The method of claim 1, further comprising the step of: - predicting whether a predetermined temperature of the metering unit (250) will be reached after said shutdown of exhaust gas flow. The method of claim 2, wherein said predetermined temperature is a functionally critical temperature for the dosage unit (250). A method according to any one of the preceding claims, wherein said at least a portion of said HC dosing system comprises some of a particulate filter, a muffler, the dosing unit (250) and the fuel. A method according to any one of the preceding claims, wherein said prediction of temperature course of said at least a part of said HC dosing system enables indirect determination of a future temperature of the dosing unit (250). A method according to any one of the preceding claims, wherein said prediction of the temperature course involves consideration of reheating effects of at least a part of the HC dosing system. A method according to any one of the preceding claims, further comprising the step of: - predicting said temperature course of at least a part of said HC- by means of a predetermined parameter configuration. dosing system calculation model including a A method according to claim 7, wherein the step of determining said need is performed before said shutdown of exhaust flow, or the step of determining said need is performed after said shutdown of exhaust flow. A method according to any one of the preceding claims, wherein said fuel is diesel or other hydrocarbon-based fuel. An apparatus comprising an HC dosing system for exhaust gas purification, comprising a dosing unit (250) for fuel, comprising: - means (200; 210; 500) for determining a need to, after switching off an exhaust flow, cool said dosing unit (250 ) for fuel by means of fuel, characterized by - means (200; 210; 500) for predicting a temperature course of at least a part of said HC dosing system as a basis for determining said need. The device of claim 10, further comprising: - means (200; 210; 500) for predicting whether a predetermined temperature of the dosing unit (250) will be reached after said shut-off of exhaust gas fl. The device of claim 11, wherein said predetermined temperature is a functionally critical temperature of the dosage unit (250). The device of any of claims 10-12, wherein said at least a portion of said HC dosing system includes some of a particulate filter, a muffler, the dosing unit (250), and the fuel. 10 15 20 25 30 27 Device according to any one of claims 10-13, wherein said prediction of temperature course of said at least a part of said HC dosing system enables indirect determination of a future temperature of the dosing unit (250). Device according to any one of claims 10-14, wherein said prediction of the temperature course includes consideration of reheating effects of at least a part of the HC dosing system. The device according to any one of claims 10-15, further comprising: - means (200; 210; 500) for predicting said temperature course of at least a part of said HC dosing system by means of a calculation model including a predetermined parameter configuration. The device according to claim 16, wherein the means for determining said need is arranged to determine said need before said shut-off of exhaust flow, or wherein the means for determining said need are arranged to determine said need after said shut-off of exhaust flow. Device according to any one of claims 10-17, wherein said fuel is diesel or other hydrocarbon-based fuel. A motor vehicle (100; 110) comprising a device according to any one of claims 10-18. The motor vehicle (100; 110) according to claim 19, wherein the motor vehicle is something of a truck, bus or passenger car. A computer program (P) for HC exhaust gas purification systems, including a fuel metering unit (250), said computer program (P) comprising program code stored on a computer readable medium to cause an electronic control unit (200; 500). ) or another computer (210; 500) connected to the electronic control unit (200; 500) for performing the steps of any of claims 1-9. A computer program product comprising a program code stored on a computer readable medium for performing the method steps of any of claims 1-9, 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).