FR2999231A1 - Regeneration controlling controller for particle filter of motor vehicle, has module for estimating actual quantity of fuel for regeneration of filter and taking into account quantity of fuel to determine if regeneration is to be started - Google Patents

Abstract

The controller has an automat (5) for starting a regeneration of a particle filter (1) by controlling the introduction of fuel causing a rise in temperature in the filter. A derivative estimation module (7) determines whether the regeneration is to be started according to current conditions of movement of a motor vehicle. An estimation module (6) estimates the actual quantity of the fuel to be introduced for the regeneration of the particle filter and takes into account the actual quantity of the fuel to determine if the regeneration is to be started.

Description

The invention relates to the regeneration of particle filters in motor vehicles and in particular the control of such regenerations. BACKGROUND OF THE INVENTION Any vehicle equipped with a particulate filter, noted FAP thereafter, the regeneration of which is achieved through an exotherm including a diesel oxidation catalyst or DOC for "Diesel Oxydation Catalyst" in English and caused by a post-injection, suffers from "engine dilution", that is to say a run of fuel along the walls of the cylinder, which fuel then enters the oil sump, causing a mixture fuel and engine oil. This phenomenon results in the gradual degradation of the lubricating qualities of the oil, which can in extreme cases lead to engine breakage. To limit and control the effects of this dilution, estimators of this dilution have been developed. D dilution at any time is calculated by the following formula: D = Mcarb / (Mcarb + Mlub) Mcarb is the result of quantities introduced by post injections during each regeneration and amounts "evaporated" permanently, mainly out regenerations when the oil is hot.

Miub is the mass of lubricant in the presence, mass which gradually decreases by the consumption of engine oil. Mcarb and Mlub are magnitudes that evolve over time. The introduction, evaporation and oil consumption can be modeled or mapped to better take into account the engine risk during the life of the vehicle [0005] A particle filter supervisor, which is an automaton time The actual code coded in the calculator, therefore uses the dilution information as well as other estimates or descriptors to make the decision to initiate and stop a regeneration of the particulate filter. The main estimators include an estimator of the mass of soot present inside the particulate filter whose purpose is the control of soot mass at the initiation of the regeneration to avoid damaging the filter too much. with particles. This estimator is most often a combination of a soot estimation via a pressure loss criterion, and the integration of a model or a measurement of engine emissions as well as a model of soot combustion at inside the particle filter. The main estimators also include a running descriptor whose purpose is to launch the regenerations at the appropriate time, that is to say at high speed, in order to guarantee the success of the regeneration. [0007] Other estimators may be present. Without exhaustiveness, one can find for example an overconsumption estimator or aging estimators of the particulate filter. In general, we try to estimate the "degradations" of the system in order to control or limit them via actions on the system itself. It maintains engine dilution to a level of safety by a philosophy of settings called "protection dilution", which promotes less frequent regeneration, in opposition to the philosophy of settings "particle filter protection", which promotes more frequent regenerations. The "dilution protection" is done in opposition to the "FAP protection" because the "FAP protection" is a strategy of demand for low-mass intra-FAP regeneration, therefore more often and therefore by regeneration with a stronger effect. dilution. In the context of the "dilution protection", the automaton is allowed to request regenerations as it sees fit on the criterion of its main intra-FAP soot estimator until the dilution estimator reaches a certain limit level and requires the system to enter "dilution protection" mode, which then allows to contain the dilution. The consequence is a more restrictive spacing of the regenerations, thus more charged regenerations, thus more exothermic and therefore with stronger cracking effect for the particulate filter. The objective of the invention is to overcome these various disadvantages. This object is achieved according to the invention with a motor vehicle particle filter regeneration control controller, configured to trigger a regeneration by driving a fuel introduction causing a rise in temperature in the particulate filter, the regeneration control controller being configured to take into account the current driving conditions of the vehicle and determine whether a regeneration should be triggered according to the current driving conditions of the vehicle, characterized in that it is configured to estimate a current amount of fuel to be introduced for regeneration of the particulate filter and take into account the current amount of fuel to be introduced to determine if the regeneration is to be triggered. Advantageously, the controller is configured to trigger a regeneration if the current amount of fuel to be introduced is less than a threshold. Advantageously, the controller takes into account the current amount of fuel to be introduced by estimating an amount of increase in fuel dilution in a motor oil due to introduction of said current amount of fuel to be introduced and determining whether the regeneration must be triggered according to the amount of dilution increase thus estimated. Advantageously, the controller is configured to compare the amount of fuel dilution increase to a threshold and trigger the regeneration or not depending on whether the amount of dilution increase is below the threshold or not. Advantageously, the controller is configured to estimate during a regeneration a value indicative of a mathematical derivative of a value of soot mass eliminated as a function of the amount of fuel introduced, compare this indicative value of mathematical derivative of a soot mass value eliminated at a threshold and stop the regeneration when said indicative value of the mathematical derivative of the removed soot mass value is less than the threshold. Advantageously, the indicative value of mathematical derivative of the soot mass removed as a function of the amount of fuel introduced is equal to a ratio between a mathematical derivative value of soot mass eliminated as a function of the quantity of fuel introduced and a maximum achievable value of this mathematical derivative of soot mass removed as a function of the amount of fuel introduced. Advantageously, the controller is configured to estimate a quantity of fuel to be introduced to raise a temperature of the particulate filter to a regeneration temperature. Advantageously, the controller is configured to estimate a quantity of fuel to be introduced to maintain a temperature of the particulate filter at a regeneration temperature during an upcoming regeneration. Advantageously, the controller is configured to estimate the amount of fuel to be introduced to regenerate the particulate filter by adding the amount of fuel to be introduced to raise the temperature of the particulate filter to the regeneration temperature and the amount of fuel. fuel to be introduced to maintain the temperature of the particulate filter at the regeneration temperature during the next regeneration. Advantageously, the controller is configured to estimate the amount of fuel to be introduced to regenerate the particulate filter regularly during the operation of the vehicle. Other features, objects and advantages of the invention will appear on reading the detailed description which follows, with reference to the single appended figure which represents a regeneration control controller according to an embodiment of the invention. 'invention. As shown in the attached figure, the controller according to the invention comprises a soot mass estimator present in the particulate filter 1, a running descriptor 2, an estimator 3 of fuel introduction during the regeneration. course, an estimator 4 of evaporation, oil consumption, and dilution. The controller of the appended figure also has an automaton 5 whose role is to initiate or stop the regenerations. The controller of the appended figure further comprises an instantaneous introduction estimation module 6 if a regeneration is requested and compared with a threshold for decision support of the regeneration request, as will be described. below.

This instantaneous introduction estimation module 6 feeds the FAP controller 5 into a regeneration start condition. The controller also comprises a module 7 for estimating the derivative of the soot mass with respect to the amount of fuel introduced am / ai and the ratio am / ai / arn / aimax during the regeneration and comparison with a threshold for decision support of the cessation of regeneration in progress. The module 6 continuously makes recurrent estimates outside the regeneration phases. When there is a regeneration, we stop the estimation calculation of the module 6 which is no longer useful because we are in post-injection. The module 7 performs its estimation only during regeneration to identify the moment when the fact of continuing to post-injection no longer has a noticeable effect due to the low mass that burns in the particulate filter. The threshold of the module 6 is a function of the soot mass present inside the particulate filter. The greater the mass of soot, the more one is allowed to introduce fuel and vice versa. This threshold is mapped here. The threshold of the module 7 is a function of the rolling criterion. The more favorable the driving conditions, the more you can wait before asking to stop the regeneration in progress. The driving conditions during the regeneration are advantageously averaged. The threshold of the module 7 is mapped here. These thresholds can be made to depend on other quantities estimated or measured, such as distance from emptying, vehicle distance, etc. The purpose of the module 6 is to give at any time t an estimate of the introduction that should implement the regeneration to regenerate the estimated current mass of soot inside the particle filter if the customer continues to roll as he at the moment t. This module is advantageously mapped with the inputs that are a DOC T upstream temperature at the inlet of the estimated or measured diesel oxidation catalyst, an upstream temperature FAR at the inlet of the estimated or measured particulate filter, an estimated Masseintra FAR mass. soot present inside the particulate filter, and a running descriptor. Four entries involving four dimensions, here the logic of this estimator is decomposed into an estimation of the introduction to pass the current upstream FAR temperature up to the target temperature and an estimate of the introduction to maintain the temperature. FAR upstream at the target temperature. Then we add up the two estimates. The module 6 here consists of two sub modules performing respectively these two estimates. A first submodule performs the following processing. The target temperature upstream of the particulate filter in regeneration depends on the estimated soot mass and the driving conditions. Here it is re-mapped but it is advantageous to ensure consistency with the other instructions in the rest of the computer, including the heating strategy for regeneration. A necessary temperature increase is calculated as being the difference between the target temperature at the inlet of the particle filter and the current temperature at the input of the upstream particulate filter FAR = the upstream FAR-T current is FAR and depending on the the current temperature at the inlet of the diesel oxidation catalyst, the rolling conditions, the thermal losses and inertia of the lines between the exit of the diesel oxidation catalyst and the inlet of the particle filter, are calculated, for example by modeling or by mapping system, the amount of post-injection that would be required and one uses a simplified introduction model or mapping given by the simplified introduction mapping formula = f (post insertion quantity, rolling descriptor) to get an idea of the introduction necessary to compensate upstream AT FAR. The second submodule performs the following processing. Once the input temperature of the upstream particle filter FAR to its target value, maintain it at this level also costs in introduction, because of the compensation of losses in the lines for a given time. The expected duration of the regeneration with the desired and consistent regeneration efficiency of what would be required if the customer continued to roll as he does is mapped according to the estimated intra-FAP mass and driving conditions. A model or cartography depending on this duration, the target temperature upstream of the particulate filter, the upstream temperature of the diesel oxidation catalyst and the rolling conditions makes it possible to deduce the amount of post injection and a model is used. or a simplified introduction mapping given by the simplified introduction mapping formula = f (post insertion quantity, rolling descriptor) to get an idea of the introduction needed to maintain the inlet temperature of the particulate filter at its target value for the necessary duration. Finally, the sum of the estimates of the first and second sub-modules gives the forecasted quantity introduced to achieve the regeneration. Mapping and simplified dimensionless model are advantageous to be able to give in real time a correct estimate of the amount of provisional introduction. By filtering and by means of inputs and by degrading the frequency of update information "Predictive introduction", we can ship more complex models requiring several time steps to solve the possible differential equations embedded. The quantity thus estimated is compared with a threshold. If this projection of the amount of fuel introduced is less than a threshold value, it is concluded that it is useful to request a regeneration. In the case of a more complex FAP automaton, such an estimate can be an indicator favoring a demand if we put weight on this information. This functional decomposition of the module 6 into two submodules is not limiting. Indeed, it can very well be imagined that the temperature target at the inlet of the particulate filter T 'have FAR in regeneration does not exactly follow the basic profile described above in the form of a simple rise and then a maintenance. It is possible to envisage other setpoint forms with changes in the target temperature during regeneration. The purpose of this module 7 is to be the "dual" module 6 but in the regeneration phase. Henceforth regeneration has been decided and is carried out with estimated quantities evolving during regeneration, including the profile of the conductor, the inlet temperature of the particulate filter, the quantities and phases of post-injections, the introduction actually estimated during the regeneration, the mass actually estimated burned, etc. Its purpose is to continuously evaluate the rate of increase of the burned mass compared to the additional introduction that had to be made. Indeed, during a combustion of soot, the size amass burned / introduction or am / ai varies with time such a bell-shaped curve with a maximum. At first, we introduce a lot by burning almost no soot because we are raising the temperature at the input of the particulate filter. In the middle of regeneration, we have the thermal and a lot of carbon to burn. At the end of the regeneration, as soon as there is less soot in the particulate filter, ie less carbon, the small amount of soot burned compared to the quantity of fuel introduced is moreover in weaker, the compromise is degraded, and we can decide to stop the regeneration. No longer burning and it is no longer profitable to continue to introduce fuel to maintain the inlet temperature of the regenerating particulate filter. For this, we usually rely on a soot combustion model, one of the bricks of the soot mass estimator inside the particle filter. The burned mass and the introduction put being monotonous and increasing quantities, we go through the following decomposition: arn / ai = 3m / 3t. A fuel input estimator is used here to determine the quantity i. Filters, here low-pass low-time filters, are there for real-time reasons to prevent real-time taps from providing only noise. Here, the burned mass information is not available but only the mass information present in the particulate filter. So we have: arn / ai = am burnt / at = I am ultra FAwat I The end-of-module calculation is as follows: I-1 - current anlia / am / ai max [0041] In order to output only one criterion on the decay of efficiency 1..1 of the bell curve arn / ai = f (t) during a regeneration. Over the entire rise of the curve, il = 1. It is this efficiency criterion 1..1 which is compared with the minimum threshold which is a function of the average driving conditions during the regeneration to request the stopping of regeneration. In the case of a more complex FAP automaton, this efficiency criterion can be an indicator favoring the stopping of the regeneration if weight is put on this information. Thanks to the action of the two modules 6 and 7, we use the concept of introduction to better capture the good opportunities to start regeneration at lower dilution cost and stop them when regeneration begins to become less effective in terms of burnt mass per fuel quantity introduced. This removes the need to enter active "dilution protection", which significantly degrades the integrity of the particulate filter or the services in terms of customer emptying intervals. The present embodiment therefore proposes to decide at any time to start the regeneration or not depending on the potential dilution if the regeneration is launched immediately and if the customer continues to roll as it does. This allows for an optimal compromise between soot regeneration and engine dilution. It is therefore also proposed to stop the regeneration as soon as the regeneration is at the end of combustion where we begin to introduce much more to burn a given unit of amount of soot. In the present embodiment, the control unit uses a control control strategy to take into account the expected introduction if the regeneration is immediate and a fuel introduction efficiency ratio. for the combustion of soot in order respectively to optimize the triggering time and the duration of the regeneration in order to gain overall dilution and to postpone the cases of use of active "dilution protection". The two taken into account of the concept of instantaneous dilution and permanently and closer to the concept of regeneration decision, advantageously in demand and on standby, makes it possible to optimize the compromise between dilution and filtration and push back to the necessary necessary the call for active "protection dilution" in curative which then involves accelerated degradation of the particulate filter. Indeed, the "protection dilution" is only curative because the dilution potentially due to the current regeneration is not considered here to prevent or postpone the regeneration but it is only the current dilution state that is used for limit other regenerations. Alternatively one can not work in dimensionless criterion pt and directly compare arn / ai to a dimensional threshold for example in grams of soot per gram of fuel which can be mapped and can depend on the mass of soot inside the filter. particles at the start of the regeneration and average driving conditions for example. Regarding the module 6, instead of projecting the forecast introduction of the regeneration if it was launched immediately, we can push the calculation to project in terms of forecast dilution increase. Indeed the introduction as such is not bad, it is the dilution that can be responsible for engine damage. The forecast projection of the introduction is then used to calculate a predicted dilution just after the regeneration if the regeneration was started immediately. Simplifying assumptions are then that the mass of lubricant does not change, a regeneration does not last for more than thirty minutes, and that there is no evaporation during regeneration. Then, if d is the current dilution, L is the mass of current lubricant, i is the current forecast projection of introduction and D is the predicted dilution projection after regeneration: D = [Ld + i. d)] / [Ld + (i + L). (1-d)] and Adution = Dd [0050] The same maximum threshold system is then used to decide the regeneration or not. The threshold may possibly depend on the distance since the last emptying. Generally, the order of magnitude of a dilution allowed by regeneration is of the order of 0.1% to 0.3%. There is also the possibility of using other information than models or maps for the amount introduced or the mass of soot inside the particulate filter. Sensors, more complex models or simple two-dimensional tables can provide the necessary information for this calculation, the strategy remaining the same. The fact of pushing active dilution protection for customers who need it, especially urban customers, can win on different levels. First, the rate of customers needing to return to the anticipated drain is reduced to the same organic definition of particulate filter. Then, we obtain an increase of the emptying intervals. Another advantage lies in the fact of gaining in cost price of the particulate filter due to the decrease in the size of the particulate filter if we accept the same benefits of anticipation rate of emptying as before. In addition, an improvement in the total cost of ownership of the vehicle or TCO for "Total Cost Ownership" according to the English terminology. Another advantage is the protection of the components because the dilution is reduced, resulting in reduced wear of the engine block parts, and a reduction in aging as well. In addition, a possible reduction in the cost of the oil used in the original equipment is obtained.

Claims (10)

REVENDICATIONS1. A motor vehicle particulate filter regeneration control controller (1,2, ..., 7) configured to trigger (5) a regeneration by driving a fuel introduction causing a temperature rise in the particulate filter, the regeneration control controller (1,2, ..., 7) being configured to take into account the current driving conditions (2) of the vehicle and to determine whether a regeneration should be triggered according to the current driving conditions of the vehicle, characterized in that it is configured to estimate a current amount of fuel to be introduced (6) for regeneration of the particulate filter and to take into account the current amount of fuel to be introduced to determine if the regeneration is to be triggered. 2. Controller according to claim 1, characterized in that the controller is configured to trigger (5) a regeneration if the current amount of fuel to be introduced (6) is below a threshold. 3. Controller according to claim 1, characterized in that the controller takes into account the current amount of fuel to be introduced (6) by estimating an amount of increase of fuel dilution in a motor oil due to introduction of said current amount of fuel to be introduced and determining whether the regeneration should be triggered according to the amount of dilution increase thus estimated. 4. Controller according to the preceding claim, characterized in that it is configured to compare the amount of increase in dilution of fuel at a threshold and trigger the regeneration or not depending on whether the amount of dilution increase is below the threshold or no. 5. Controller according to one of the preceding claims, characterized in that it is configured to estimate during a regeneration a value indicative of a mathematical derivative (7) of a soot mass value eliminated as a based on the amount of fuel introduced, compare this mathematical derivation value (7) of the removed soot mass value with a threshold and stop the regeneration (5) when this indicative value of the mathematical derivative of the soot mass value eliminated is below the threshold. 6. Controller according to the preceding claim, characterized in that the mathematical derivative indicative value (7) of the mass of soot removed as a function of the amount of fuel introduced is equal to a ratio between a mathematical derivative value mass of soot removed as a function of the amount of fuel introduced and a maximum achievable value of this mathematical derivative of soot mass removed as a function of the amount of fuel introduced. 7. Controller according to one of the preceding claims, characterized in that it is configured to estimate a quantity of fuel to be introduced (6) to raise a temperature of the particulate filter to a regeneration temperature. 8. Controller according to one of the preceding claims, characterized in that it is configured to estimate a quantity of fuel to be introduced (6) to maintain a temperature of the particulate filter at a regeneration temperature during a future regeneration. 9. Controller according to claim 7 and claim 8 in combination, characterized in that it is configured to estimate the amount of fuel to be introduced (6) to regenerate the particulate filter by adding the amount of fuel to introduce to raise the particle filter temperature up to the regeneration temperature and the amount of fuel to be introduced to maintain the temperature of the particulate filter at the regeneration temperature during the next regeneration. 10. Controller according to any one of the preceding claims, characterized in that it is configured to estimate the amount of fuel to be introduced (6) to regenerate the particulate filter regularly during operation of the vehicle.