FR3073428A1 - METHOD FOR ADAPTING EMISSION ADDITION TO ASSIST REGENERATION OF A PARTICLE FILTER - Google Patents

Abstract

The invention relates to a method of adapting the additive to emissions to aid the regeneration of a particulate filter in an exhaust line of a combustion engine of a motor vehicle. A set amount of additive to be injected into the fuel after each fuel filling is estimated proportionally to an amount of fuel added taking into account a first calibrator ratio of an amount of additive to be added to an amount of fuel added during filling. In order to adapt the adivation to the emissions, a second ratio (T ad inj) is taken into account according to the regenerations carried out for the particulate filter and a mass of soot present in the particulate filter. The final ratio adopted is the maximum between the first and second ratios (T ad inj).

Description

METHOD FOR ADAPTING THE ADDITIVATION TO EMISSIONS TO AID IN THE REGENERATION OF A PARTICLE FILTER The present invention relates to a method for adapting the additivation to emissions in order to aid in the regeneration of a particulate filter in a heat engine exhaust line of a motor vehicle. The present invention also relates to a device for injecting an additive to aid the regeneration of a particle filter in a fuel contained in a motor vehicle for implementing the method and a motor vehicle equipped with such a injection device.

The present invention relates mainly to compression ignition engines, in particular diesel or diesel engines. However, as the use of particle filters is generalized for all kinds of motorization, the present invention can find an application for internal combustion engines with spark ignition, in particular a petrol or mixture fuel engine containing petrol, filters with particles specially designed for petrol engines being used more and more.

The additive may be a compound of a liquid based on cerium, also called cerine, based on a mixture of cerium and iron or based solely on iron, but this is not limiting.

The additive is introduced by an additive injection device into the fuel. The additive, in the form of ferric oxides or Fe2O3 and / or cerium oxides or CeO2, is supplied directly inside the agglomerates of carbon and unburnt hydrocarbons which form the soot at the time of combustion in the engine. The additive, acting as a catalyst during regeneration, is thus placed uniformly in the soot.

The additive injection device for assisting the regeneration of a particulate filter in the fuel comprises an additive reservoir, a pump for injecting the additive into the fuel controlled by a unit of control command imposing a setpoint for the quantity of additive to be injected into the fuel after each filling with fuel at the injection pump. The additive injection pump can be wired or multiplexed.

It is known to transmit to the additive injection pump a setpoint for the quantity of additive to be injected proportional to the fuel additions detected by an intelligent service unit or to requests in the terminal factory or after sales. provided that an additive injection authorization is present.

The injection of additive is only authorized under vehicle speed criteria for reasons of feeling by the passengers of the vehicle. It is not necessary to inject this additive immediately after detecting an addition of fuel.

According to the state of the art, the amount of additive injected is proportional to the amount of fuel added, but this amount of additive injected does not depend on emissions and does not take into account the state of fouling of the particle filter. It follows that, according to the state of the art, it is not possible to adapt an additive injection instruction by considering a mass ratio of additive to mass of soot contained in the particle filter according to the fouling rate of the particulate filter.

For information, to determine the optimal loading of the particulate filter, an estimate of its aging state is made. The aging considered takes into account, on the one hand, the fouling of the inlet channels in ash residues, coming from the lubricant or the additive or from other sources and, on the other hand, the cracking of the ceramic. due to the progress of previous regenerations.

However, the oxidation of the active element of the additive is counted among one of the sources of pollution which produces permanent residues in the particle filter and the clog.

The volume of particulate filter fouled in additive ash, fuel and oil must be estimated to calculate the free volume of the particulate filter. From the mass of residues and from the geometric dimensions of the filter media, the fouling volume is determined.

Figure 1 shows a functional architecture of additive injection according to the state of the art present in a control unit command of the additive injection device which is integrated in a command control of the CMM engine under load the operation of the engine.

The BSI intelligent service unit gives the parameters necessary for validating the fuel supply Val c by detecting the fuel supply Ap c by the intelligent service unit and taking into account the first start of the engine control. Dem CMM.

Authorization for the injection of additive Aut a in nominal mode, in the terminal plant or in after-sales service Name UT APV is managed by the command and control unit of the additive injection device. The Niv a authorization conditions are with the engine running, a speed exceeding a minimum threshold and a critical additive level not reached.

COM communication allows the calculation of the volume of additive remaining Vol a and the calculation of the cumulative mass M FAP in the particle filter. This communication is based on information from the processing chain and the particulate filter supervisor.

After validation of the fuel supply, the additive setpoint C a is determined. Once the conditions for authorizing the additivation are met, the Ginj additive is injected into the fuel tank. If the additivation pump is of the multiplexed type there is a shift P pump return from the CoC.

It is performed a management of requests in terminal factory mode and in the after-sales world G UT APV which takes into account and maintains the requests in the terminal factory and in after-sales Shift UT APV.

On the other hand, according to this state of the art, no parameter is taken into account relating to the regenerations and to the mass of soot contained in the particle filter.

Therefore, the problem underlying the present invention, in a motor vehicle comprising a heat engine with an exhaust line housing a particulate filter, an additive to aid the regeneration of the particulate filter being added to vehicle fuel, is to determine an amount of additive to inject into the fuel taking into account the condition of the particulate filter.

To achieve this objective, there is provided according to the invention a method of adapting the additivation to emissions to aid in the regeneration of a particulate filter in an exhaust line of an engine of a vehicle automotive, a setpoint of quantity of additive to be injected into the fuel after each filling with fuel being estimated in proportion to a quantity of fuel added by taking into account a first calibratable ratio of a quantity of additive to be added to a quantity of fuel added during filling, characterized in that a second ratio is taken into account which is a function of the regenerations carried out for the particle filter and a mass of soot present in the particle filter, the final ratio adopted being the maximum between the first and second ratios.

The technical effect is to change the additive injection function to allow an injection of an amount of additive adapted to the real need of a particle filter for optimal regeneration. This injection of additive depends on the volume of fuel injected and the emissions.

The ppm ratio allowing the calculation of the volume of additive to be injected according to the prior art is fixed. The invention aims, under certain conditions, to make it dependent on emissions from new information provided by a particulate filter supervisor. The calculation of the volume of additive to be injected henceforth depends on the volume of fuel added and on the condition of the particulate filter. A new ppm ratio as the second ratio is determined as a function of the regeneration of the particle filter and the mass of soot, with advantageously a value between 5 and 12 ppm. The new functionality allows you to choose the maximum of the two ratios between the first fixed ratio for example at 5 ppm by calibration and the second ratio which is new and variable for calculating the volume of additive to be added.

The main purpose of such a method is to avoid activation of an alert representative of an overloaded particulate filter on a specific indicator displayed on the dashboard in the passenger compartment of the motor vehicle when the filter filter diagnosis overloaded particle is reassembled.

The quality of the fuel is different according to the country and also the behavior of the drivers significantly influence the durability of the particulate filter. When the regeneration of the particulate filter is interrupted or takes place in bad conditions, then the particles burn badly and the particulate filter is overloaded. The first ratio according to the prior art which is fixed is not sufficient in these cases of life and the solution was to carry out an additional injection of additive.

The technical and economic interest of the present invention is to adapt the injection of additive for a more optimal regeneration of the particulate filter.

A first count of the number of regenerations carried out is carried out, a second count of regenerations activated on severe driving conditions, such as exclusive urban driving, short driving times of less than 20 kilometers at speed less than 50 kilometers / hour, a long run in the mountains and conditions for activating previous regenerations not reached or interrupted during regeneration and a third count of soot mass regenerations incrementing when the mass of soot detected in the particulate filter is greater at a tolerated soot mass threshold.

It is thus determined the three counts characterizing the charge of the particle filter. The first count is made on regeneration and the second count is representative of the driving conditions which may be specific to the driver. The third count concerns the estimation of the mass of soot in the particle filter, therefore its level of fouling in force.

The method according to the invention makes it possible to adapt the injection of additive according to the use of the vehicle and to determine the life cases where there is a large production of soot due to regenerations activated on conditions severe driving. The second count shows whether the driving mode affects the production of soot, while the third count determines whether the soot load in the particulate filter is high or not. The first count makes it possible to follow the total number of regenerations therefore to see if these regenerations are frequent or not.

This regulates the injection of additive by adapting it to the driving conditions of the motor vehicle by being able to apply an over-injection of additive following a detection of overproduction of soot. In life cases where there is an overproduction of soot or an accumulation of the mass of soot in the intolerable particulate filter, the amount of additive injected should be increased.

The calculation of the volume of additive to be added depends on the second ratio adapted to the running of the vehicle. The calculation of the volume of additive to be added now depends on the volume of fuel added and the condition of the particulate filter. This strategy must make it possible to increase the rate of additive injection for highly emissive traffic in order to preserve an additive / soot ratio compatible with good regeneration efficiency.

Advantageously, the second ratio is calculated either by a first mapping taking into account the first and second counts, or by a second mapping taking into account the first and third counts or either by taking as the second ratio the maximum ratio between the ratio of the first mapping and the ratio of the second mapping.

The mass of soot in the particulate filter is detected by a model or by analysis of a pressure differential across the particulate filter.

The model is based on gas emissions in an exhaust line estimated at the outlet of the engine giving the masses of soot retained in the particle filter as a function of engine speed and engine torque during successive durations and accumulating them.

Regenerations with a regeneration duration less than a minimum regeneration duration are not counted in the first and / or the second count. This minimum duration can be fixed at three minutes, which corresponds to a very incomplete regeneration.

The first, second and third counts are reset to zero:

- a fourth count being made concerning the fuel additions, when a number of fuel additions counted by this fourth count exceeds a predetermined addition threshold,

- during an after-sales request relating to a change of at least one parameter of the particle filter influencing the charge of the particle filter, such as a change of the particle filter or a cleaning of the particle filter,

- by forced reset.

Advantageously, the first and second ratios are fixed in particles per million, the first ratio being established at 5 particles per million with a range of variation of 20% around this figure and the second ratio being established between minimum figures and maximum of 5.

The invention relates to a device for injecting an additive to aid the regeneration of a particulate filter in a fuel contained in a motor vehicle, the injection device comprising an additive reservoir, a fuel additive injection pump controlled by a control unit imposing a setpoint for the quantity of additive to be injected into the fuel after each filling of fuel to the injection pump, characterized in that the unit control command comprises means for determining an amount of additive to be injected for implementing such a determination method.

The invention finally relates to a motor vehicle comprising a heat engine with an exhaust line at the outlet of the heat engine comprising a particulate filter and a fuel tank, characterized in that it comprises such an injection device , the injection pump injecting the quantity of additive into the fuel tank, the fuel tank being associated with means for determining an addition of fuel and a value of the amount of fuel added to the fuel tank and means for communicating the value of the quantity of fuel added to the control unit command of the injection device.

The method according to the invention has an impact on the longevity of the particulate filter. The driver of the motor vehicle will be asked much later to change his particle filter. The solution proposed by the present invention directly aims at a more optimal regeneration of the particulate filter with respect for the durability of the particulate filter.

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with regard to the appended drawings given by way of nonlimiting examples and in which:

- Figure 1 shows a functional architecture for the injection of additive present in a control unit controlling the injection device which is integrated in a control unit controlling the engine in charge of the operation of the heat engine, this architecture being according to l 'state of the art,

FIG. 2 shows a functional architecture for the injection of additive present in a control unit controlling the injection device which is integrated in a control unit controlling the engine in charge of the operation of the heat engine, this architecture being according to the present invention,

FIG. 3 shows a flow diagram of an embodiment of the method according to the present invention,

FIG. 4 shows a reset to zero of the four counters following a fuel supply exceeding a predetermined addition threshold according to an implementation of an embodiment of the determination method according to the invention,

- Figure 5 shows an evolution of the calculation of a ratio of quantity of additive to inject to quantity of fuel according to a mass count of soot accumulated in the particulate filter and the number of times there has been regeneration of the particulate filter.

It should be borne in mind that the figures are given by way of examples and are not limitative of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily at the scale of practical applications. In particular, the dimensions of the various elements illustrated are not representative of reality.

In what follows, reference is made to all the figures taken in combination. When reference is made to one or more specific figures, these figures are to be taken in combination with the other figures for the recognition of the designated numerical references.

Figure 1 has already been described in the introductory part of the present application.

Figure 2 essentially shows all the elements of an architecture of the prior art with the addition in place of a CdT control module of an adaptation of the additive setpoint Shift a, this which represents the contribution of the process according to the invention to the state of the art, the process being designated by Strag a for an injection device called AddGO.

In Figure 2, the contribution of the invention is reflected in taking into account the fouling state of the particle filter and the number of regenerations, which is referenced Reg FAP. A second ratio is also calculated based at least on the mass of soot, which is referenced Reg M. The other references remain unchanged with respect to FIG. 1.

Referring to all the figures, the present invention therefore relates to a method of adapting the additivation to emissions to aid in the regeneration of a particulate filter in an exhaust line of an internal combustion engine. motor vehicle. A set quantity of additive C a to be injected into the fuel after each filling of fuel is estimated in proportion to a quantity of fuel added by taking into account a first calibratable ratio of a quantity of additive to be added to a quantity of fuel added during filling.

According to the invention, a second ratio T ad inj is taken into account as a function of the regenerations carried out for the particle filter and of a mass of soot present in the particle filter, which is referenced Reg FAP, the regulation by the second ratio T ad inj being referenced Reg M for regulation by mass. The final ratio adopted is the maximum between the first ratio determined according to the state of the art and the second ratio T ad inj, determined specifically by the present invention.

Referring to Figure 3, It can be performed a first count Nb RG Early the number of regenerations performed under the following condition Cond: if the number of fuel addition is greater than a threshold for example 10, the first count as well as the second Nb RG BF and third counts Nb RG sm which will be described are reset.

Indeed, it can also be carried out a second count Nb RG BF of regenerations activated on severe driving conditions, such as an exclusive urban driving, short driving times of less than 20 kilometers at speed below 50 kilometers / hour , long driving in the mountains and conditions for activating previous regenerations not reached or interrupted during regeneration.

In addition, a third count Nb RG sm of regenerations in soot mass can be carried out which is incremented when the mass of soot detected in the particulate filter is greater than a predetermined filling threshold.

According to a preferred embodiment of the present invention, the second ratio T ad inj is calculated either by a first mapping Ta taking into account the first Nb RG early and third counts Nb RG sm, or by a second mapping Ta taking take into account the first Nb RG early and second count Nb RG BF or either by taking as second ratio T ad inj the maximum ratio between the ratio of the first mapping Ta and the ratio of the second mapping Ta.

In Figure 3, there is shown a single map Ta which can act as one or the other of the maps. The second ratio T ad inj is calculated by the mapping Ta.

The mass of soot in the particulate filter can be detected by a model or by analysis of a pressure differential across the particulate filter. The pressure differential can be done in a closed loop based on a back pressure detected by a pressure sensor connected to the terminals of the particle filter.

The model can be based on gas emissions in an exhaust line estimated at the outlet of the heat engine giving the masses of soot retained in the particle filter as a function of engine speed and engine torque for successive durations and accumulating them, this for successive durations.

The soot masses can be multiplied by a multiplicative safety factor greater than one and integrated to give a critical total mass of soot in the particle filter.

It is possible to combine the model with estimates according to the gas emissions which are done in open loop and estimates of the soot masses obtained by back pressure measurements made in closed loop. The advantages of the two types of loop are thus associated.

Regenerations having a regeneration duration less than a minimum regeneration duration may not be counted in the first and / or the third count Nb RG sm. This minimum regeneration time can be three minutes with a deviation of +/- 20% around this value.

Figure 4, also referring to Figure 3, shows a reset to zero of all the meters following the validation of the last fuel addition. The fuel addition counter has exceeded the predetermined addition threshold (N additions). Ca C designates the fuel additions during the fourth Nb GO count. Nb RG FAP designates the counting of regenerations of the particle filter or first counting. Su Cum FAP BF designates the mass of soot accumulated in the particle filter. The third Su Cum FAP BF count is incremented when the mass of soot detected in the particulate filter is greater than a predetermined filling threshold with a mass of soot which can be estimated by closed-loop backpressure. INF bi is binary information to be validated before calculating the additive volume the quantity of fuel added.

To have a representative image of the running of the vehicle and its effect on the regeneration of the particle filter, a fourth count saturated with N fuel additions, for example 10 additions, which is a calibrated value is incremented after validation of the added fuel volume. The additive is adapted to these N fuel additions. This fourth count is used to reset the first Nb RG Early, second Nb RG BF and third Nb RG sm counts.

The first Nb RG Early, second counts Nb RG BF and third Nb RG sm can be reset to zero when the fourth count Nb GO concerning the fuel additions indicates a number of fuel additions counted by this fourth count Nb GO exceeding a predetermined additions threshold, for example 10.

As an alternative, the first Nb RG Early, second Nb RG BF counts and third Nb RG sm can be reset to zero during an after-sales request relating to a change in at least one parameter of the particle filter influencing the charge of the particulate filter, such as changing the particulate filter or unclogging the particulate filter. Clogging is a filter cleaning operation that can only be done in the workshop and that a regular regeneration cannot perform. Finally, the first Nb RG Early, second Nb RG BF counts and third Nb RG sm can be reset by forced reset.

FIG. 5 shows a validation of the fuel intake as a function of regeneration and soot mass counts in the particle filter according to an implementation of an embodiment of the determination method according to the invention, this as a function of the time recorded in seconds. The counting of regenerations is done by a counter of the mass of soot accumulated in the particle filter, advantageously in a closed loop, which is referenced Su Cum FAP BF.

The number of times there has been a regeneration of the particle filter during the N fuel additions is referenced Nb RG FAP. The second ratio T ad inj is used to determine the volume of additive to be injected Vol a and a request for regeneration of the particle filter is referenced Req RG FAP.

Without being limiting, the first and second ratios T ad inj are fixed in particles per million, the first ratio being established at 5 particles per million with a range of variation of 20% around this figure and the second ratio T ad inj being established between 5 and 12 with a variation range of 20% around the minimum and maximum figures.

The invention also relates to a device for injecting an additive to aid in the regeneration of a particle filter in a fuel contained in a motor vehicle, the injection device comprising an additive reservoir, a pump for injecting the additive into the fuel controlled by a control unit imposing a setpoint for the quantity of additive C a to be injected into the fuel after each filling with fuel at the injection pump.

According to the invention, the control unit comprises means for determining an amount of additive to be injected for implementing a determination process as described above.

The invention finally relates to a motor vehicle comprising a heat engine with an exhaust line at the outlet of the heat engine comprising a particle filter and a fuel tank.

According to the invention, the motor vehicle comprises an injection device as described above, the injection pump injecting the amount of additive into the fuel tank, the fuel tank being associated with determination means an addition of fuel and a value of quantity of fuel added to the fuel tank and means of communicating the value of quantity of fuel added to the command and control unit of the injection device.

The command and control unit of the injection device can be integrated into an engine command and control unit responsible for the operation of the heat engine.

The invention is in no way limited to the embodiments described and illustrated which have been given only by way of examples.

Claims (10)

1. Method for adapting the additive to emissions to aid in the regeneration of a particulate filter in an exhaust line of a heat engine of a motor vehicle, an additive quantity instruction (C a) to injecting into the fuel after each filling with fuel being estimated in proportion to an amount of fuel added, the volume of additive determined taking into account two ratios, a first fixed ratio of an amount of additive to be added to an amount of fuel added during filling, a second variable ratio (T ad inj), depending on the regenerations carried out for the particle filter and a mass of soot present in the particle filter, the final ratio adopted being the maximum between the first and second ratios (T ad inj). 2. Method according to the preceding claim, in which a first count (Nb RG Early) of the number of regenerations carried out is carried out, a second count (Nb RG BF) of regenerations activated on severe driving conditions, such as exclusive urban driving, short driving times of less than 20 km at a speed of less than 50 km / hour, long driving in the mountains and conditions for activating previous regenerations not reached or interrupted during regeneration, a third count (Nb RG sm) , function of the mass of soot, incrementing when the mass of soot detected in the particulate filter is greater than a predetermined filling threshold. 3. Method according to the preceding claim, in which the second ratio (T ad inj) is calculated either by a first mapping (Ta) taking into account the first (Nb RG Early) and third counts (Nb RG sm), or by a second mapping (Ta) taking into account the first (Nb RG Early) and second counts (Nb RG BF) or either by taking as second ratio (T ad inj) the maximum ratio between the ratio of the first mapping (Ta) and the ratio of the second mapping (Ta). 4. Method according to any one of claims 2 or 3, wherein the mass of soot in the particulate filter is detected by a model or by analysis of a pressure differential across the particulate filter. 5. Method according to the preceding claim, in which the model is based on gas emissions in an exhaust line estimated at the outlet of the heat engine giving the masses of soot retained in the particle filter as a function of an engine speed and of a motor torque for successive durations and accumulating them. 6. Method according to any one of claims 2 to 5, in which the regenerations having a regeneration duration less than a minimum regeneration duration are not counted in the first (Nb RG Tôt) and / or the third count (Nb RG sm). 7. Method according to any one of claims 2 to 6, in which the first (Nb RG Early), second (Nb RG BF) and third counts) are reset: - a fourth count (Nb GO) being made concerning the fuel additions, when a number of fuel additions counted by this fourth count (Nb GO) exceeds a predetermined addition threshold, - during an after-sales request relating to a change of at least one parameter of the particle filter influencing the charge of the particle filter, such as a change of the particle filter or a cleaning of the particle filter, - by forced reset. 8. Method according to any one of the preceding claims, in which the first and second ratios (T ad inj) are fixed in particles per million, the first ratio being established at 5 particles per million with a range of variation of 20% around of this figure and the second ratio (T ad inj) being established between minimum and maximum figures of 5 and 12. 9. Device for injecting an additive to aid the regeneration of a particulate filter in a fuel contained in a motor vehicle, the injection device comprising an additive reservoir, an injection pump for the additive in the fuel controlled by a control unit imposing a setpoint for the quantity of additive (C a) to be injected into the fuel after each filling with fuel at the injection pump, characterized in that the control unit control includes means for determining an amount of additive to be injected for implementing the determination method according to any one of the preceding claims. 10. Motor vehicle comprising a heat engine with an exhaust line at the outlet of the heat engine comprising a particulate filter and a fuel tank, characterized in that it comprises an injection device according to the preceding claim, the pump d injection injecting the quantity of additive into the fuel tank, the fuel tank being associated with means for determining an addition of fuel and a value for the amount of fuel added to the fuel tank and means communication of the value of the quantity of fuel added to the control unit command of the injection device.