CN112648094A

CN112648094A - Method for emission-based trajectory planning for an internal combustion engine

Info

Publication number: CN112648094A
Application number: CN202011070629.5A
Authority: CN
Inventors: M.格兰; J.卡帕; M.戈帕拉克里希南
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2019-10-11
Filing date: 2020-10-09
Publication date: 2021-04-13
Also published as: DE102019215617A1

Abstract

The invention relates to a method for emission-based trajectory planning for an internal combustion engine. The invention relates to a method for emission-based trajectory planning (10) for an internal combustion engine of a motor vehicle. Taking measures (60) in at least one coordinator of the motor vehicle according to the past emission and/or the current emission (21) and/or the predicted emission (22) of the internal combustion engine.

Description

Method for emission-based trajectory planning for an internal combustion engine

Technical Field

The invention relates to a method for emission-based trajectory planning for an internal combustion engine of a motor vehicle. Furthermore, the invention relates to a computer program implementing each step of the method; and to a machine-readable storage medium storing the computer program. Finally, the invention relates to an electronic control device which is set up to carry out the method.

Background

The following software packages exist in the engine control apparatus software of a gasoline internal combustion engine: the software package models portions of a system that includes an internal combustion engine and its exhaust after-treatment device. For example, a catalyst or a particulate filter is modeled. In addition, the software has a coordinator (Koordinator). The different packets communicate with each other and here send the requirements and status to further packets. Currently, via application program guarantees, different requirements with priorities are registered and thereby the defined flow is guaranteed. In the case of this application, the following policies are also specified: the strategy is no longer changed during continuous operation of the internal combustion engine. The strategy involves prioritizing the requirements according to the system state and thereby simultaneously the emissions emitted.

In the case where the emissions are not observed, torque adjustment for implementing the driver's desired torque is performed. In addition to the regulation of the current emissions with respect to compliance with legal limits, the driving behavior of a motor vehicle driven by an internal combustion engine is also not taken into account.

Disclosure of Invention

In a method for emission-based trajectory planning for an internal combustion engine of a motor vehicle, in particular a gasoline engine, measures are taken in at least one coordinator of the motor vehicle as a function of past and/or current and/or predicted emissions of the internal combustion engine. Here, no action, one action, or a plurality of actions may be taken. The predicted emissions can be obtained in particular by: past driving behavior is taken into account so that predictions for future behavior can be made. If a future driving distance is available, for example, on the basis of the navigation data, this future driving distance can be taken into account in the prediction.

The internal combustion engine can be the sole drive unit of the motor vehicle or can also be used in hybrid solutions (for example in cooperation with an electric motor).

The method enables compliance with emission target values to be ensured for each possible driving style (real driving). In contrast to routine selection of the operating strategy, which defines the actuation of one or more regulators of the internal combustion engine (ansuerung) at which the measures are permanently linked by an application to a specific situation, such as for example to an engine start or engine warm-up process, the method enables intelligent emission evaluation. It is thereby possible to design a system which is robust with respect to all driving situations (robust). In this Case, system applications to Worst-Case scenarios (Worst-Case-Szenario) do not have to take place, as a result of which unnecessarily high carbon dioxide emissions often occur in standard scenarios. In the method, the system strategy with regard to emissions can be defined centrally and can therefore be well specified in the scope of certification to the control authority.

Preferably, in the vehicle coordinator and/or in the engine coordinator and/or in the exhaust gas coordinator and/or an subordinate coordinator (unterkorrdinator), measures are taken and the regulator is actuated there in order to be able to achieve the driver-desired torque on the one hand and to be able to carry out all measures required for achieving the emission target on the other hand. The so-called coordinator can be part of the central coordinator, including other partial coordinators, or the central coordinator for trajectory planning can likewise communicate directly with the subsystems.

Furthermore, it is preferred that the past emissions (in particular with regard to the unit distance or the unit time, are obtained via an integrator with suitable reset conditions or via a smoothed intermediate value) and/or the current emissions and/or the predicted emissions are compared with a threshold value for each emission type. This enables observation of the course of variation of the respective emissions, wherein the threshold value is the target value for the respective emission. The emission types may include, for example, carbon dioxide emissions, soot emissions, and heat emissions.

Preferably, for each emission type, the priority is calculated according to the distance of the emission of that emission type from the respective threshold. By means of which the priority can be quantified: how important is to reduce the emissions of the respective emission type under the current conditions. Priority may be specified, for example, on a scale from 0 to 100, where a priority of 100 may be given for emissions near the threshold, and a priority of 0 may be given for emissions away from their respective threshold. Priority may also be given to exceeding 100 for the respective emission type, for example up to 255, if the determination is based on the respective past emissions and/or the respective current emissions and/or the respective prediction of emissions that is imminent exceeding the threshold.

Furthermore, it is preferred that the different executable measures are assigned in the coordinator in each case a cost factor for the emissions increased for each passing measure and a utility factor (Nutzenfaktor) for the emissions reduced for each passing measure. In this case, the cost factor and the utility factor can be dynamically changed, for example as a function of the rotational speed of the internal combustion engine or the temperature of the catalytic converter, taking into account the system state. Furthermore, in order to determine the cost factor and the utility factor of the respective measure, a prediction of the system state can be carried out via models (e.g. combustion models and exhaust gas models) in order to determine the effect of the respective measure on different emissions. The measures are different possible system interventions for reducing specific emissions. Generally, measures that result in a reduction of emissions of at least one emission type simultaneously result in an increase of emissions of at least one further emission type. Whereby, in general, each measure is assigned at least one cost factor and at least one utility factor.

The cost factor, utility factor and priority are preferably applied in the method by: for each possible measure for each emission type, by means of which it is possible to vary the emission of said emission type, in the case of an increased emission the cost factor is multiplied by the priority in order to obtain a cost value, and in the case of a reduced emission the utility factor is multiplied by the priority in order to obtain a utility value. The following results are used as a decision basis for the coordinator for trajectory planning: the result is obtained by subtracting the sum of all cost values for the measure from the sum of all utility values for the measure.

It is also preferred that, before taking the measures, the measures are checked: whether these measures are in harmony with the existing higher priority requirements (e.g., component protection) of the package, or whether additional constraints limit the choice of measures. The package used to model portions of the system may require requirements for its operation, such as, for example, particulate filter regeneration, heating of a catalyst, or heating of a combustion chamber of an internal combustion engine. Measures which counteract these requirements or make them impossible are prevented in this way.

In consideration of cost/utility values and available measures, a trajectory plan for an operating strategy of the internal combustion engine is developed in the central coordinator in order to optimally operate the internal combustion engine with respect to all emission types of the internal combustion engine (in particular carbon dioxide emissions, nitrogen oxide emissions and soot emissions). By selecting a specific operating strategy, the control unit (e.g., injection unit and ignition unit) of the internal combustion engine is controlled in a predetermined manner.

The computer program is set up as: in particular, each step of the method is carried out when the computer program is run on a computing device or on an electronic control device. The implementation of different embodiments of the method on an electronic control unit can be achieved without structural changes being necessary for this. For this purpose, the computer program is stored on a machine-readable storage medium. By operating (Aufspielen) this computer program on a customary electronic control device, the following electronic control device is obtained: the electronic control unit is designed to carry out an emission-based trajectory planning for the internal combustion engine by means of the method.

Drawings

Embodiments of the invention are illustrated in the drawings and are set forth in more detail in the description that follows.

Fig. 1 shows a schematic system diagram of a motor vehicle for which a trajectory planning can be carried out with an embodiment of the method according to the invention.

Fig. 2 schematically shows trajectory planning according to an embodiment of the invention.

Fig. 3 schematically shows a measure determination in a trajectory planning of a method according to an embodiment of the invention.

Detailed Description

In an exemplary embodiment of the invention, a motor vehicle, not shown, has a concentrated emission-optimized trajectory plan 10 for the internal combustion engine of the motor vehicle. In fig. 1, it is shown with solid arrows how the requirements are made in this case; how the status report is transmitted is shown with dashed arrows; and with dotted arrows it is shown how the strategy for the measures to be carried out is delivered. The trajectory planning 10 is supplied with the current emissions 21 of the internal combustion engine. Current emissions include: gaseous emissions, such as for example carbon dioxide emissions and nitrogen oxide emissions, particulate emissions, such as for example soot particulate emissions, and thermal emissions. Values that allow to infer emissions, such as for example lambda values, can also be transmitted in this case. Furthermore, the trajectory planning 10 is supplied with predicted data 22, which predicted data 22 enables a prediction of emissions. This prediction is performed, for example, in consideration of the previous driving behavior and the forward estimation of the future driving behavior. Furthermore, range data from the navigation system may be considered. For example if based on the driving profile determination thus obtained: if sufficient heat for the regeneration of the particle filter has already been introduced into the particle filter of the motor vehicle, it is predicted that no further reheating of the particle filter is necessary for the planned regeneration of the particle filter, and this can be taken into account in the predicted emissions. The emissions emitted so far are likewise taken into account and stored as internal states in the trajectory planning 10. This can occur via integration of emissions with respect to time or distance traveled, under suitable reset conditions or with a smooth average of emissions from the past. Finally, the trajectory planning is provided with a threshold value 23 for all emissions, which threshold value 23 should serve as a target value for the optimization and should not exceed the threshold value 23.

If the trajectory planning 10 has determined which measures are to be taken for the exhaust-gas-optimized operation of the internal combustion engine, these measures are forwarded to the coordinator of the motor vehicle. The coordinators include a vehicle coordinator 31, an engine coordinator 32 of the internal combustion engine, and an exhaust coordinator 33. The exhaust gas coordinator 33 comprises in the present embodiment sub-coordinators, namely a lambda coordinator 331, a temperature management device 332, a catalyst coordinator 333 and a particle filter coordinator 334.

Details of the functioning of the trajectory planning 10 are shown in fig. 2. First, past and current emissions 21 and predicted emissions 22 are evaluated 11, taking into account the threshold 23. To this end, each emission type whose emissions do not exceed, and are not expected to exceed, the respective threshold is assigned a priority in the range from 0 to 100, wherein the lower the priority, the further away the emissions are from their threshold. If exceeding the threshold is imminent or has been exceeded, the relevant emission type is assigned a priority greater than 100, the higher the priority, the more the threshold is exceeded. Thereby, the priority may take a value of up to 255, for example. The higher the priority, the more important it is to take measures in order to reduce emissions of the respective emission type.

The strategy module 12 of the trajectory planning 10 is supplied with the requirements 40 of the package of motor vehicles. This includes, for example, requirements with respect to particulate filter regeneration, particulate filter loading, catalyst heating and combustion chamber heating. The strategy module 12 is also supplied with the readiness 50 of the components of the motor vehicle, which include, for example, the exhaust system of the motor vehicle, the internal combustion engine of the motor vehicle, a start-stop function, a cruise function, an ESP and the possibility for shifting gears. The policy module 12 determines which actions 60 are to be taken by the

coordinators

31, 32, 33.

In fig. 3, the functionality of the policy module 12 is illustrated in more detail. Based on the vehicle readiness 50, the following evaluations 121 are made: which measures can be executed in the current state of the motor vehicle. Next, a decision 122 is made as a function of priority P for one or more of measures 60. If the emissions are increased by means of measures 60, a cost factor Kf is registered for each measure 60 for each emission affected by these measures; whereas if the emissions are reduced by the measure, the utility factor Nf is registered. The cost value K for each emission having a cost factor Kf is obtained by multiplying the cost factor Kf by the priority P of the emission. A utility value N is obtained for each emission having a utility factor Nf by multiplying the utility factor Nf by the priority P of the respective emission. The following results are used as a decision basis 122 to implement action 60: the result is obtained by subtracting the sum of the cost values K of the measures 60 from the sum of the utility values N of the measures 60. This is shown in table 1 as an example as a measure 60 for the prohibition of a Fuel Cut (Fuel-Cut-Off) for a certain time duration.

Table 1

Discharging	P	Kf	Nf	K	N

CO
	₂	50	20	0	1000
Soot						20	0	40	800

In the current operating state of the motor vehicle, carbon dioxide (CO) emissions are aimed at₂) A priority P of 50 has been determined. A priority P of 20 has been determined for discharging soot. For the measure "fuel cut off forbidden" (which results in increased CO)₂Reducing soot particulate emissions in the case of emissions), a cost factor Kf of 20 has been determined for carbon dioxide and a utility factor Nf of 40 for soot. By performing the multiplication described above, a cost value K of 1000 is obtained for carbon dioxide and a utility value N of 800 is obtained for soot. Therefore, in the present operating state, it is determined that no action is to be performed, since the cost of the operating state may be higher than its utility.

Furthermore, in the policy module 12, a decision 123 is made for each measure 60: based on the existing requirements 40 and the limitations of the further software package, whether this measure 60 can be executed or not. The measure is only carried out immediately when the check 124 yields that the decision 123 on the measure is positive and only when the decision basis 122 on the measure yields that the measure is optimal for reaching the emission target. In this way, the emissions of the internal combustion engine can be optimally adjusted by means of the trajectory planning 10. The check 124 can result in that, in the present state, no action 60 is carried out, one action 60 is carried out, or a plurality of actions 60 are carried out simultaneously.

Claims

1. A method for emission-based trajectory planning (10) for an internal combustion engine of a motor vehicle, characterized by taking measures (60) based on past emissions and/or current emissions (21) and/or predicted emissions (22) of the internal combustion engine.

2. Method according to claim 1, characterized in that the measures (60) are taken in the vehicle coordinator (31) and/or in the engine coordinator (32) and/or the exhaust gas coordinator (33) and/or the subordinate coordinator (331) and 334) and the regulators are operated there.

3. Method according to claim 1 or 2, characterized in that the past emissions and/or the current emissions (21) and/or the predicted emissions (22) are compared with a threshold value (23) for each emission type, respectively.

4. A method according to claim 3, characterized in that, for each emission type, the priority (P) is calculated according to the distance of the emission of that emission type from the respective threshold (23).

5. Method according to claim 4, characterized in that for the measures (60) executable in the coordinator (31, 32, 33), a cost factor for each emission increased by the measure and a utility factor for each emission reduced by the measure are determined, respectively.

6. The method according to claim 5, characterized in that the cost factor and the utility factor are determined dynamically via a model taking into account the influence of the respective measure in dependence on the current and/or predicted system state.

7. Method according to claim 5 or 6, characterized in that each cost factor is multiplied with the priority (P) of the emissions being raised in order to obtain a cost value; each utility factor is multiplied by the priority (P) of the reduced emissions in order to obtain a utility value; and the sum of all utility values of the measure (60), subtracted by the sum of all cost values of the measure (60), is a decision basis for taking the measure (60).

8. The method according to any one of claims 1 to 7, characterized in that the action (60) is checked (124) before the action (60) is taken: whether the measures (60) can be coordinated with the existing requirements (40) of the package.

9. A computer program set up to perform each step of the method according to any one of claims 1 to 8.

10. A machine-readable storage medium on which a computer program according to claim 9 is stored.

11. An electronic control unit which is designed to carry out a trajectory planning (10) for an internal combustion engine by means of a method according to one of claims 1 to 8.