DE102018102029A1 - A method for scheduling a regeneration of components of an exhaust aftertreatment system - Google Patents

Abstract

The invention relates to methods of scheduling regeneration of components of an exhaust aftertreatment system of a motor vehicle, comprising the steps of predicting a distance based on parameters stored in a controller, calculating expected rating factors G over the distance to be traveled according to the formula: wherein for a variable x and an associated limit value x travel-dependent parameters are used and where te is a running variable of the time, and the scheduling of a start time of the regeneration, wherein the starting time is a start of a time window (T) predetermined time (t.), in which the calculated rating factors G on the Time window (T) are above a predetermined limit value (G).

Description

The invention relates to a method for planning a regeneration of components of an exhaust aftertreatment system of a motor vehicle and a control device for carrying out such a method.

From the DE102004005072A1 For example, a method for regenerating an exhaust gas aftertreatment system is known, in which a control device is supplied with information data relating to the route, on the basis of which a regeneration is controlled.

wobei für eine Variable x und einen dazugehörigen Grenzwert x_krit fahrtabhängige Parameter verwendet werden und wobei t_n eine Laufvariable der Zeit ist. Darüber hinaus umfasst das Verfahren den Schritt des Planens eines Startzeitpunktes der Regenerierung, wobei der Startzeitpunkt ein Beginn eines Zeitfensters vorgegebener Zeit ist, bei welchem die berechneten Ratingfaktoren G über das Zeitfenster oberhalb eines vorgegebenen Grenzwertes G_Grenz liegen, oder wobei als Startzeitpunkt ein Zeitpunkt innerhalb eines Zeitbereiches gewählt wird, in dem die berechneten Ratingfaktoren G oberhalb eines vorgegebenen Grenzwertes (G_Grenz) liegen und in dem ein für die vorhergesagte Strecke maximaler Ratingfaktor (G_max) erzielt wirdThe inventive method for scheduling a regeneration of components of an exhaust aftertreatment system of a motor vehicle comprises the steps of predicting a distance based on stored in a controller parameters, and calculating expected rating factors G on the route to be traveled according to the formula: $$G=\{\begin{array}{ll}x\ge x_{krit}\hfill & G\left(t_n\right)=G\left(t_{n-1}\right)+y\hfill \\ x<x_{krit}\{\begin{array}{c}G\left(t_{n-1}\right)\ge 0\\ G\left(t_{n-1}\right)<0\end{array}\hfill & \begin{array}{c}G\left(t_n\right)=G\left(t_{n-1}\right)-z\\ G\left(t_n\right)=G\left(t_{n-1}\right)+0\end{array}\hfill \end{array}$$

where _critical variable-dependent parameters are used for a variable x and an associated threshold x, and where t _{n is} a run variable of the time. In addition, the method includes the step of scheduling a start time of the regeneration, wherein the start time point is a start of a time window of predetermined time in which the calculated rating factors G are over the time window is above a predetermined limit value G _limit, or in which as the start time point is a time within a Time range is selected in which the calculated rating factors G are above a predetermined limit (G _limit ) and in which a for the predicted route maximum rating factor (G _max ) is achieved

For regeneration, it is necessary that the components to be regenerated do not fall below a minimum temperature necessary for the regeneration over a certain period of time. When falling below this temperature regeneration usually has to be stopped. The method according to the invention has the advantages that a regeneration of the components can be carried out with fewer crashes. Since each regeneration is associated with increased fuel consumption, can be saved by reducing the crashes CO ₂ . Furthermore, in the event that regeneration is required on the prospective route, the inventive method allows the regeneration to be carried out at least partially at an advantageous time, even if there should be no time window in which complete regeneration is possible.

As components to be regenerated, for example, a diesel particulate filter (DPF) or a lean NOx trap (LNT) is understood. During regeneration, the diesel particulate filter is freed of the soot and the lean NOx trap of the NOx or SOx.

The values y and / or z can be fixed constant values. It is preferred that the values y and z are function values of a function. The function is preferably dependent on a loading of the LNT and / or DPF, on the soot and / or NOx deposition and the combustion rate, and / or the LNT and / or DPF temperature, which is advantageously downstream.

In a preferred embodiment of the invention, a regeneration is performed at a first time window. As a result, a regeneration is made as early as possible. This has the advantage that a regeneration can take place relatively regularly, so that a regeneration does not have to be postponed to later rides.

In a further preferred embodiment of the invention, a regeneration is performed at a time window in which, after the predetermined time has elapsed, a maximum rating factor G for the predicted route is achieved. This selects a time window for which the probability of a cancellation of the regeneration within the predicted route is very small. This can save CO ₂ .

Alternatively, regeneration is performed at a time window at which an average slope of the calculated rating factors G becomes maximum over a predetermined time. Again, a time window is determined for which there is a low probability of termination, so that CO ₂ can be saved.

Preferably, a vehicle speed v, an actual vehicle power P or an engine torque M is used for the variable x. For example, a value of 105 or 110 km / h could be selected for the vehicle speed. By evaluating these parameters, a prediction of the further trip can be made. This makes it possible to make a more accurate prediction as to whether a regeneration must be aborted or not. In addition, the most favorable range can be better selected for regeneration.

It is advantageous if the value for the critical vehicle speed is adjusted, wherein the value for the critical vehicle speed over the expected distance to be traveled is reduced until an average gradient of the rating factor G increases at least the predetermined time. It can thus be provided sufficient time for regeneration. As a result, an abort probability of the regeneration is substantially reduced.

In an advantageous embodiment of the invention, a destination input of a navigation system for the prediction of a route to be traveled is used in the control device. This allows a better prediction of the route to be traveled, allowing better planning with fewer crashes.

In a further advantageous embodiment of the invention, a route to be traveled on the basis of stored in the controller usually driven routes determined. These routes are stored, for example, on the basis of the time of day and the day of the week, so that a habitual profile can be set on the basis of which data over which routes can be predicted. This makes it even better to predict the distance to drive.

Advantageously, traffic-dependent parameters are included in the planning. Such traffic-dependent parameters can be, for example, traffic jams, road closures or construction sites. This information can be received either via the traffic radio (eg Traffic Message Channel) or via the mobile internet. As a result, track areas can be taken into account, in which it is likely to stop the regeneration. This can reduce crashes of regeneration and thus reduce CO ₂ emissions.

According to an advantageous development of the invention, a smaller value is chosen for the variable y than for the variable z. This makes it possible to better predict long phases with a supercritical value. Thus, a valence is introduced in which a subcritical range is rated higher than a supercritical range. For example, a value of 1 can be used for y and a value of 2 for x.

In an advantageous embodiment, a control device is set up to carry out the method for planning a regeneration of components of an exhaust aftertreatment system.

• 1 Verfahren zum Planen einer Regenerierung von Komponenten einer Abgasnachbehandlungsanlage nach einem ersten erfindungsgemäßen Ausführungsbeispiel,
• 2 Verfahren zum Planen einer Regenerierung von Komponenten einer Abgasnachbehandlungsanlage nach einem zweiten erfindungsgemäßen Ausführungsbeispiel,
• 3 Verfahren zum Planen einer Regenerierung von Komponenten einer Abgasnachbehandlungsanlage nach einem dritten erfindungsgemäßen Ausführungsbeispiel, und
• 4 Verfahren zum Planen einer Regenerierung von Komponenten einer Abgasnachbehandlungsanlage nach einem vierten erfindungsgemäßen Ausführungsbeispiel,

Further advantages of the invention will become apparent from the following description of the figures of the preferred embodiments. It shows

• 1 Method for planning a regeneration of components of an exhaust aftertreatment system according to a first embodiment of the invention,
• 2 Method for planning a regeneration of components of an exhaust aftertreatment system according to a second embodiment of the invention,
• 3 A method for scheduling a regeneration of components of an exhaust aftertreatment system according to a third embodiment of the invention, and
• 4 Method for planning a regeneration of components of an exhaust aftertreatment system according to a fourth embodiment of the invention,

berechnet. Der Wert t_n ist dabei eine Laufvariable der Zeit innerhalb der vorhergesagten Strecke. Der Wert t_n-1 ist der dazugehörige vorherige Zeitwert zu t_n. In 1 ist ein Grenzwert G_Grenz eingezeichnet, oberhalb dessen eine Regeneration überhaupt erst möglich ist. Für die Regeneration wird ein Zeitfenster T_Fenster mit einer vorgegebenen Zeit t_Reg. angenommen, welches notwendig ist, um die Regeneration vollständig abschließen zu können. Innerhalb dieses Fensters T_Fenster muss der Ratingfaktor G dauerhaft oberhalb des Grenzwertes G_Grenz liegen. Für den in 1 über die Zeit t aufgetragenen Verlauf des Ratingfaktors G ergeben sich somit drei mögliche Zeitfenster T_Fenster, in denen eine Regeneration möglich ist. Nach dem ersten Ausführungsbeispiel wird dabei eine Regeneration direkt bei dem ersten Zeitfenster T_Fenster durchgeführt. Dadurch kann verhindert werden, dass bei einer Abweichung des tatsächlichen Verlaufs des Ratingfaktors G, nach dem ersten Zeitfenster T_Fenster, bei welchem keine weiteren geeigneten Zeitfenster mehr kommen, trotz alledem eine Regeneration stattfinden konnte.The 1 shows a predicted course of a rating factor G for distance based on stored in a controller parameters. These parameters can be via a destination input of a navigation system, stored in the controller usually driven routes and / or traffic-dependent parameters are determined. The rating factor G is based on a parameter x _crit , which is, for example, a speed v, a current vehicle power P or an engine torque M, from the formula $$G=\{\begin{array}{ll}x\ge x_{krit}\hfill & G\left(t_n\right)=G\left(t_{n-1}\right)+y\hfill \\ x<x_{krit}\{\begin{array}{c}G\left(t_{n-1}\right)\ge 0\\ G\left(t_{n-1}\right)<0\end{array}\hfill & \begin{array}{c}G\left(t_n\right)=G\left(t_{n-1}\right)-z\\ G\left(t_n\right)=G\left(t_{n-1}\right)+0\end{array}\hfill \end{array}$$

calculated. The value t _n is a running variable of the time within the predicted route. The value t _n-1 is the associated previous time value to t _n . In 1 a limit G _{limit is} drawn above which regeneration is possible in the first place. For regeneration, a time window T is _window with a predetermined time t _Reg . assumed, which is necessary in order to complete the regeneration completely. Within this window T _window , the rating factor G must be permanently above the limit value G _limit . For the in 1 Over the course of time t applied course of the rating factor G thus result in three possible time window T _windows in which a regeneration is possible. According to the first embodiment, a regeneration is performed directly at the first time window T _window . In this way, it can be prevented that, in the event of a deviation of the actual course of the rating factor G, after the first time window T _window , during which no further suitable time windows are more, a regeneration could nevertheless take place.

The values y and / or z may be fixed constant values, for example y = 1 and z = 2. In a preferred embodiment, the values y and z are function values of a parameter-dependent function. The function is preferably dependent on a loading of the LNT and / or DPF, on the soot and / or NOx deposition and the combustion rate, and / or the LNT and / or DPF temperature, which is advantageously downstream. In a further embodiment, instead of the first time window T _window , a second possible time window T _window can also be used. This can ensure that the components could heat up over a sufficiently long period of time.

2 shows the same predicted course of a rating factor G as in 1 , At the in 2 In the second exemplary embodiment shown, instead of the first time window T _window, a time window T _{window is} used in which the rating factor G is above G _limit , and in which, after the predetermined time t _Reg . a maximum rating factor G _{max is} achieved for the predicted route. As a result, an area for the regeneration can be determined, in which the least number of crashes must be expected.

der berechneten Ratingfaktoren G, für dieses Zeitfenster T_Fenster von allen geeigneten Zeitfenstern T_Fenster, maximal ist. Das sich hierbei ergebende für die Regeneration optimale Zeitfenster T_Fenster unterscheidet sich dabei von den in den ersten beiden Ausführungsbeispielen ermittelten Zeitfenstern T_Fenster.In 3 is the same course of the rating factor G as in 1 and 2 shown. In contrast to the first two exemplary embodiments, in the third exemplary embodiment the time window T _window determined for the regeneration, in which the rating factor G is above G _limit, is selected such that an average gradient $\frac{\mathrm{\Delta }G}{\mathrm{\Delta }t}$

the calculated rating factors G, for this time window T _windows of all suitable time windows T _window , is maximum. The resulting here for the regeneration optimal time window T _window differs from the time windows T _window determined in the first two embodiments.

4 shows a method for planning a regeneration of components of an exhaust aftertreatment system according to a fourth embodiment of the invention. In this figure is shown with reference to a x _crit adjusting the value, as the course of the rating factor G varies. In this exemplary embodiment, the speed of the motor vehicle is assumed as the value for x. In other embodiments, however, the use of the current vehicle power P or the engine torque M is also conceivable. In the embodiment shown, is for x _crit once a vehicle speed v of 110km / h and once assumed a speed of 105 km / h. It can be seen that there is no possible time window T results _window for a regeneration of the velocity v of 110km / h. At a speed of 105 km / h, however, at least a sufficiently large time window T _window results within which regeneration is possible. By means of such an adaptation, the optimum range for regeneration can be found in each case for the predefined route to be traveled. Such an adaptation of the speed v may be made in the method for scheduling regeneration of components of an exhaust aftertreatment system by the controller. This in 4 shown time window T _window is selected as in embodiment two such that at the end of the time window, a maximum rating factor G _{max is} achieved.

According to one variant, there is no time window available over the planned route, in which the condition G> G _{limit is} fulfilled and within which a complete regeneration can be carried out. In this case, a time within a time range in which the calculated rating factors G are above a predetermined limit value (G _limit ) and in which a maximum rating factor (G _max ) for the predicted distance is achieved is selected as the start time. This is advantageous because the time range in which G has its maximum is generally the time range in which G is the longest over the limit, whereby the regeneration can be carried out with as few interruptions as possible. The regeneration is preferably started at the time when G exceeds the threshold. This makes it possible to exploit the entire time range as long as G is greater than G _limit . Regeneration may continue in a subsequent time range where G is greater than the threshold. The choice of the time range can be selected on the basis of time criteria or an efficiency criterion. For example, the subsequent time range can be selected to complete the regeneration as quickly as possible, or a time range that allows the most complete regeneration or the completion of the regeneration.

des Ratingfaktors G wenigstens die vorgegebene Zeit t_Reg. ansteigt.In another embodiment, it is also conceivable to reduce the value for the example critical speed until an average slope $\frac{\mathrm{\Delta }G}{\mathrm{\Delta }t}$

the rating factor G at least the predetermined time t _Reg . increases.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102004005072 A1 [0002]

Claims (10)

A method of scheduling a regeneration of components of an exhaust aftertreatment system of a motor vehicle, comprising the steps of: - prediction of a distance based on parameters stored in a control device, - calculation of expected rating factors G on the distance to be traveled according to the formula: $$G=\{\begin{array}{ll}x\ge x_{krit}\hfill & G\left(t_n\right)=G\left(t_{n-1}\right)+y\hfill \\ x<x_{krit}\{\begin{array}{c}G\left(t_{n-1}\right)\ge 0\\ G\left(t_{n-1}\right)<0\end{array}\hfill & \begin{array}{c}G\left(t_n\right)=G\left(t_{n-1}\right)-z\\ G\left(t_n\right)=G\left(t_{n-1}\right)+0\end{array}\hfill \end{array}$$

where _critical parameters are used for a variable x and an associated limit value x, and where t _{n is} a running variable of the time, and scheduling a start time of the regeneration, wherein the starting time is a start of a time window (T _window ) of predetermined time (t _reg .), in which the calculated rating factors G lie above a predefined limit value (G _limit ) over the time window (T _window ), or where a time within a time range is selected as the start time point, in which the calculated rating factors G are above a predetermined limit value ( G _limit ) and in which a maximum rating factor (G _max ) is achieved for the predicted route. A method for scheduling a regeneration of components of an exhaust aftertreatment system according to Claim 1 , characterized in that a regeneration at a first time window (T _window ) is made. A method for scheduling a regeneration of components of an exhaust aftertreatment system according to Claim 1 , characterized in that a regeneration is carried out at a time window (T _window ), in which an average slope $\left(\frac{\mathrm{\Delta }G}{\mathrm{\Delta }t}\right)$

the calculated rating factor G becomes maximum over a predetermined time (t _Reg .). A method of scheduling a regeneration of components of an exhaust aftertreatment system according to any one of the preceding claims, characterized in that for the variable x, a vehicle speed (v), an actual vehicle power (P) or a motor torque (M) is used. A method for scheduling regeneration of components of an exhaust aftertreatment system according to any one of the preceding claims, characterized in that the value for the critical vehicle speed is adjusted, whereby the value for the critical vehicle speed over the expected route to be traveled is reduced until an average slope $\left(\frac{\mathrm{\Delta }G}{\mathrm{\Delta }t}\right)$

of the rating factor G at least the predetermined time (t _Reg .) Increases. A method for planning a regeneration of components of an exhaust aftertreatment system according to one of the preceding claims, characterized in that in the control device, a destination input of a navigation system is used for the prediction of a route to be traveled. A method for planning a regeneration of components of an exhaust aftertreatment system according to any one of the preceding claims, characterized in that a distance to be traveled on the basis of stored in the control device usually traveled routes determined. Method for planning a regeneration of components of an exhaust aftertreatment system according to one of the preceding claims, characterized in that traffic-dependent parameters are included in the planning. A method of scheduling a regeneration of components of an exhaust aftertreatment system according to any one of the preceding claims, characterized in that for the variable y is a smaller value than for the variable z is selected. Control device, set up for carrying out a method according to one of Claims 1 to 9 ,

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