CN111287828A

CN111287828A - Method and control device for operating an internal combustion engine

Info

Publication number: CN111287828A
Application number: CN201911241812.4A
Authority: CN
Inventors: C.卢茨; D.海因里希; G.尼科洛夫; J.达米茨
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-12-07
Filing date: 2019-12-06
Publication date: 2020-06-16
Also published as: DE102018221243A1

Abstract

A method is proposed for controlling an internal combustion engine (12) of a motor vehicle (10) which is equipped with a navigation device (14) and has an exhaust system (26), in which method the internal combustion engine (12) can be operated with the same output in a first operating state and in a second operating state which differs from the first operating state by a higher carbon dioxide emission, wherein in the first operating state the current temperature of the exhaust system (26) is determined and it is determined whether heating of the exhaust system (26) is necessary. The method is characterized in that the future temperature occurring in the exhaust system (26) when switching into the second operating state is predicted on the basis of data of a future route, which data are provided by the navigation device (14). An independent claim is directed to the controller (20).

Description

Method and control device for operating an internal combustion engine

Technical Field

The present invention relates to a method according to the preamble of claim 1 and a controller according to the preamble of the independent device claim.

In its method aspect, the invention relates to the control of an internal combustion engine of a motor vehicle which is equipped with a navigation device and has an exhaust system in which at least one exhaust gas aftertreatment component is arranged, through which the exhaust gas of the internal combustion engine flows, which exhaust gas aftertreatment component a function of which can be recovered discontinuously, in which method the internal combustion engine can be operated with the same output in a first operating state and in a second operating state, which second operating state differs from the first operating state by a higher carbon dioxide emission, wherein in the first operating state the current temperature of the exhaust system is determined and whether it is necessary to heat the exhaust system is determined on the basis of the determined temperature. In its device aspect, the invention relates to a controller which is provided for carrying out such a method.

Background

It is a prerequisite that such a method and such a controller are known per se. Exhaust aftertreatment components that do not continuously recover function are known to recover function at relatively high temperatures. One example of an exhaust aftertreatment component that does not continuously recover function is a particulate filter. Such a particulate filter filters out soot particles from the exhaust gas of an internal combustion engine and is thereby loaded with deposited soot particles. The recovery function of the loaded particulate filter is not continuously performed due to the operating conditions resulting from the presence of excess oxygen in the exhaust gas and the exhaust gas temperature being so high that soot deposited in the particulate filter is burned. The high exhaust gas temperature is achieved by corresponding operation of the internal combustion engine. The exhaust device may also be heated in conjunction with a high exhaust gas temperature to bring the exhaust gas aftertreatment component to the minimum temperature required for its function after a cold start, or to maintain its temperature above the minimum temperature.

If the engine is operated at low load for a longer period of time, the heating may not be sufficient to reach the desired temperature. After a predeterminable time, the heating is stopped. After a further predeterminable time, the heating is switched on again. The additional consumption of fuel required for futile heating attempts and the associated increased carbon dioxide emissions are useless. Overall, this results in increased carbon dioxide emissions.

Disclosure of Invention

The method according to the invention differs from the prior art known from this premise by the characterizing features of claim 1 and thereby by predicting the future temperature in the exhaust system when changing into the second operating state on the basis of data of a future route, which data are provided by a navigator. Accordingly, the controller according to the invention differs from the prior art in that the future occurring temperature is additionally predicted from traffic information and/or additional data from mobile data communication and/or signals of other vehicle sensor systems.

By predicting the temperatures of the exhaust gas and the exhaust gas system components from the future driving route, the motor controller also has information for the operation of the motor on the future driving route, which influences the temperatures of the exhaust gas and the exhaust gas system components. According to the invention, this information is used to optimize the heating strategy. For this purpose, the heating measures are only triggered if success can also result.

By specifically activating the heating measures, unnecessary additional fuel consumption is avoided.

A preferred embodiment of the method is characterized in that the predicted temperature is compared with a target value and the change into the second operating state is effected only if the predicted temperature is higher than the target temperature.

By means of these features, the increased heating of the exhaust gas device is triggered only if there is a high probability that the target temperature sought can also be reached and/or maintained on the basis of the exhaust gas temperature prediction. The carbon dioxide emissions associated therewith are also avoided since possibly insufficient heating attempts are not triggered at all.

It is also preferable to select, when shifting from the first operating state to the second operating state, the measure that achieves the target earliest under future expected conditions, among the plurality of measures for increasing the amount of carbon dioxide emissions.

In the case of low torque demands and cold exhaust, the internal combustion engine can be operated, for example, with an increased combustion chamber filling and with a compensatory retarded ignition, in order to generate hot exhaust gases. Conversely, if the exhaust is already hot and there is not a sufficiently high torque margin, a late injection may be associated with excess oxygen in the exhaust. This produces an exothermally reacting exhaust gas environment in the exhaust gas system, which leads to a corresponding further heating.

It is further preferred that the selection is made in accordance with the predicted temperature when selecting from among a plurality of measures for increasing the emission amount of carbon dioxide and possible action strengths of the measures.

A further preferred embodiment of the method is characterized in that at least two measures for increasing the carbon dioxide emissions are selected in stages as a function of the predicted exhaust gas temperature.

It is also preferred that the decision as to whether the activation of the first means for increasing the emission of carbon dioxide results in a minimum temperature being reached in the exhaust within a predetermined time, which minimum temperature requires the second means for increasing the emission of carbon dioxide to exert a heating effect, is based on the predicted temperature of the exhaust.

It is further preferred that the change from the first operating state into the second operating state is triggered only when a start condition is met, which is dependent on at least one further input variable.

With regard to the design of the controller, it is preferred that the controller is provided, in particular programmed, for carrying out at least one of the described designs.

Further advantages emerge from the dependent claims, the description and the drawings.

It is to be understood that the features mentioned above and yet to be explained below can be applied not only in the respective given combination but also in other combinations or individually without departing from the scope of the present invention.

Drawings

Embodiments of the invention are illustrated in the drawings and are explained in detail in the following description. The same reference numbers in different figures denote identical or at least functionally comparable elements, respectively. In the drawings, in schematic form:

FIG. 1 illustrates the technical environment of the present invention; and

fig. 2 shows a flow chart as an embodiment of the method according to the invention.

Detailed Description

FIG. 1 shows in detail an automotive vehicle 10 having an internal combustion engine 12, a navigator 14 and a vehicle sensor system 16. The navigator 14 is arranged to receive and process data from an external data source 18. The vehicle sensor system 16 has, for example, a suspension sensor (Einfederungssensor) which is informed of the load state of the motor vehicle 10. The external data sources 18 are those that enable the navigation device 14 to determine its position and convey information about traffic density.

The internal combustion engine 12 has, in particular, a controller 20, a plurality of sensors 22, a plurality of actuators 24, and an exhaust 26. The exhaust device 26 has an exhaust aftertreatment component 28, such as a particulate filter, with a discontinuous recovery function. The exhaust gas aftertreatment component 28 optionally has a temperature sensor 30, which detects a current temperature T _ a of the exhaust gas aftertreatment component 28 and/or of the exhaust gas of the internal combustion engine 12. Alternatively or additionally, the temperature T _ a may also be calculated by the controller 20 from signals of other sensors 22.

The sensor 22 detects operating parameters of the internal combustion engine 12, such as the amount of intake air, the rotational speed, and the temperature. The actuators 24 are, for example, air mass adjusting mechanisms, fuel injection valves and also in gasoline motors or spark plugs, and the actuators 24 and sensors 22 described are not intended to represent an exhaustive list.

Fig. 2 shows a flow chart as an embodiment of the method according to the invention. The method is implemented by the controller 20. Step 100 represents a main routine for controlling the internal combustion engine 12, in which the internal combustion engine 12 is first operated in a first operating state.

From step 100, step 110 is reached, in which the current temperature T _ a of exhaust gas system 26 in the first operating state is determined.

Query 120 follows step 110, in which it is checked whether exhaust device 26 should be heated. A decision is made as to whether there is a need to heat exhaust device 26 based on the current temperature T _ a that is known and optionally based on other current values, for example, based on the current operating point (relative fill, torque, speed) and other variables of the motor controller.

If the answer to this query is negative, the method returns to step 100, in which the internal combustion engine 12 continues to operate in the first operating state.

Conversely, when heating is due, the query 100 is answered in the affirmative, and the method branches to step 130, in which the future temperature T _ P of the exhaust device 26 that will occur in the presence of certain conditions is predicted.

One of the conditions is that the internal combustion engine 12 is operated in the second operating state, which differs from the first operating state by a higher carbon dioxide emission, i.e., a higher fuel consumption. In this case, the internal combustion engine 12 is operated in the second operating state in such a way that a higher fuel consumption leads to heating of the exhaust system 26.

The measures associated with higher carbon dioxide emissions may include, in particular, individual measures such as changing the injection mode, increasing the idle speed, limiting the supply of fresh air and retarding the ignition, or also combinations of these measures, but this list is not exhaustive.

The other conditions are derived in particular from data of future travel routes, which are provided by the navigator 14 and passed to the controller 20. In particular, data about uphill and downhill slopes (preferably including steepness and length, respectively) and the type of route (freeway, highway, city) can be taken into account.

Additionally, traffic information from mobile data communication and/or additional data, for example regarding traffic density and/or average speed to be expected, may also be processed in predicting temperatures that will occur in the future. Alternatively or additionally, signals from other vehicle sensors 16 of the motor vehicle 10 can also be used, for example suspension sensors of a headlight illumination width control device, the signals of which reflect the load and thus the mass of the motor vehicle 10 to be accelerated.

In a comparison step 140, which follows step 130, the predicted temperature T _ P is compared with a target value T _ Z. If the predicted temperature T _ P is less than the target value T _ Z, the method returns to the main routine (step 100) without initiating measures for heating the exhaust device 26. The reason for this is that the measure on which the predicted temperature T _ P is based for heating the exhaust device 26 is not sufficient to reach the target temperature. When the temperature is not high enough, the exhaust aftertreatment component 28 does not perform a sufficient recovery function either, so that the additional fuel consumption associated with the activation of the heating measures is put in vain.

If, on the other hand, the predicted temperature T _ P is higher than the target temperature T _ a, the method branches to query step 150, in which it is checked whether at least one opening condition is fulfilled. It may also be one of a plurality of turn-on conditions, for example, that the current operating altitude of the motor vehicle 10 is not greater than a predetermined maximum value.

If one of the opening conditions is not met, the method branches back to step 100, in which the internal combustion engine 12 continues to operate in the first operating state. Conversely, if all the turn-on conditions are met, the method branches to step 160. In step 160, the internal combustion engine 12 is operated in the second operating state, i.e. the carbon dioxide emissions are increased for heating purposes. In a subsequent step 170, it is checked whether the internal combustion engine 12 is to continue to be operated in the second operating state. If this is the case, the method returns again to step 160, thereby maintaining the second operating state.

If, on the other hand, the check in step 170 reveals that the internal combustion engine 12 should no longer be operated in the second operating state, the method returns to step 100 again, in which the internal combustion engine 12 is operated in the first operating state without heating measures for increasing the carbon dioxide emissions.

In a preferred embodiment, the predicted temperature is formed for different heating measures. When changing from the first operating state to the second operating state, the measure that achieves the target at the earliest under future conditions to be expected is selected among the plurality of measures for increasing the carbon dioxide emissions.

If only one heating measure or only one combination of heating measures leads to the target of the target temperature being reached, the heating measure or the combination of heating measures is carried out. If the target temperature can be reached by a plurality of and thus mutually substitutable heating measures or combinations of heating measures, the heating measure or combination of heating measures which increases the carbon dioxide emissions minimally occurs is preferably carried out as the main target (als zielfuehrand).

Alternatively, a heating measure or a combination of heating measures is preferably carried out as a main objective, which also has a heating action margin (Reserve) present, which can be activated if the development of the current temperature lags behind the predicted temperature. The latter case may occur, for example, in unexpected events that are not considered in the prediction, such as in sudden and unexpected occurrences of traffic congestion.

When selecting from among a plurality of measures for increasing the emission amount of carbon dioxide and possible action strengths of the measures, the selection is made in accordance with the predicted temperature. The higher the predicted temperature, the more effective the heating measure or combination of heating measures should be to be able to reach the predicted temperature also reliably.

In one embodiment, at least two measures for increasing the carbon dioxide emissions are selected in stages as a function of the predicted exhaust gas temperature. This means, for example, that a measure is first selected which is used to bring the temperature up to a first temperature, and then, when the first temperature is reached, a second measure is initiated, by means of which a target temperature above the first temperature is reached.

The second measure can be, for example, chemical heating, for which purpose, by retarding the ignition and/or retarding the injection point, in conjunction with the air-excess operation of the internal combustion engine, a reactive exhaust gas atmosphere is produced in the catalyst. The first temperature is, for example, the light-off temperature of a catalytically active component of the exhaust gas device, for example a catalytic coating of a particle filter.

The light-off temperature is an example of the lowest temperature in the exhaust device that requires a second measure to increase carbon dioxide emissions to function as a heating element. In one embodiment, it is determined, based on the predicted temperature of the exhaust system, whether the activation of the first means for increasing the carbon dioxide emissions leads to the lowest temperature being reached within a predetermined time. The predetermined time preferably corresponds to a predicted time range, i.e. a time period during which the exhaust gas temperature can be predicted with sufficient probability.

Claims

1. Method for controlling an internal combustion engine (12) of a motor vehicle (10) which is equipped with a navigation device (14) and has an exhaust system (26) in which at least one exhaust gas aftertreatment component (28) is arranged, through which the exhaust gas of the internal combustion engine (12) flows, the function of which can be restored discontinuously, in which method the internal combustion engine (12) can be operated with the same output in a first operating state and a second operating state, which differs from the first operating state by a higher carbon dioxide emission, wherein in the first operating state the current temperature of the exhaust system (26) is determined and it is determined whether it is necessary to heat the exhaust system (26) on the basis of the determined temperature, characterized in that, on the basis of data of future driving routes, a prediction is made as to the data of a future driving route in the exhaust system (26) when changing into the second operating state A future occurring temperature, wherein data of the future travel route is provided by the navigator (14).

2. Method according to claim 1, characterized in that the future occurring temperature is predicted additionally from traffic information and/or additional data from mobile data communication and/or signals of other vehicle sensor systems (22).

3. A method according to claim 1 or 2, characterized in that the predicted temperature is compared with a target value and the change into the second operating state is made only when the predicted temperature is higher than a target temperature.

4. Method according to any one of the preceding claims, characterized in that, in the transition from the first operating state into the second operating state, among the plurality of measures for increasing the carbon dioxide emissions, the measure that reaches the target earliest under future conditions to be expected is selected.

5. The method according to claim 4, characterized in that the selection is made on the basis of the predicted temperature when selecting from a plurality of measures for increasing carbon dioxide emissions and possible action strengths of said measures.

6. The method according to claim 4 or 5, characterized in that at least two measures for increasing the carbon dioxide emission are selected stepwise in dependence on the predicted exhaust gas temperature.

7. The method according to claim 6, characterized in that it is decided, on the basis of the predicted temperature of the exhaust unit (26), whether the activation of the first means for increasing the emission of carbon dioxide results in a minimum temperature being reached in the exhaust unit (26) within a predetermined time, which minimum temperature requires the second means for increasing the emission of carbon dioxide to exert a heating effect.

8. A method according to claim 4 or 5, characterized in that a change from the first operating state into the second operating state is triggered only when a switch-on condition is fulfilled, which switch-on condition depends on at least one further input variable.

9. A controller (20) which is provided for controlling an internal combustion engine (12) of a motor vehicle (10), which motor vehicle (10) is equipped with a navigator (14) and has an exhaust system (26) in which at least one exhaust-gas aftertreatment component (28) is arranged, through which exhaust gas of the internal combustion engine (12) flows, wherein the controller (20) is provided for operating the internal combustion engine (12) with the same output in a first operating state or in a second operating state, which differs from the first operating state by a higher carbon dioxide emission, wherein the controller (12) is provided for ascertaining the current temperature of the exhaust system in the first operating state and for determining whether it is necessary to heat the exhaust system (26) as a function of the ascertained temperature, characterized in that the control unit (20) is provided for predicting a future temperature in the exhaust system (26) when changing into the second operating state as a function of data of a future travel route, which data are provided by the navigation device (14).

10. The controller (20) according to claim 9, characterized in that it is provided for, in particular programmed for, performing the method according to any one of claims 2 to 8.