KR20160012089A - Method and device for determining an target-operating parameter of an internal combustion engine - Google Patents

Abstract

The present invention relates to a method for determining a target-operating parameter (M_soll_ICE) of an internal combustion engine. The target-operating parameter (M_soll_ICE) is selected depending on a target-operating parameter limiting value (AbsLim, GradLim). The target-operating parameter limiting value (AbsLim, GradLim) is determined such that an emission characteristic parameter value of an internal combustion engine is smaller than a predetermined emission limiting value.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and an apparatus for determining a target operating parameter of an internal combustion engine,

The present invention relates to a method for determining a target operating parameter of an internal combustion engine. In another aspect, the present invention relates to a computer program, an electronic memory medium, and a control apparatus for executing the method.

DE 10 2007 019 989 A1 discloses a method of operating a hybrid drive having at least one electric machine and at least one combustion engine, wherein the hybrid drive generates a desired drive torque and at the same time the target output of the electric machine is maintained .

DE 10 2007 019 989 A1 proposes a method having the following steps:

Generating a plurality of characteristic maps each of which minimizes the emission of harmful substances in the hybrid driving section and to which the first driving torque of the electric machine and the second driving torque of the combustion engine are respectively assigned to the hybrid driving rotational speed and the hybrid driving torque,

Selecting a characteristic map such that the target output is maintained or not falling; and

Operating the hybrid drive with drive torque output from the selected characteristic map;

It is an object of the present invention to provide a method for determining a target operating parameter of an internal combustion engine.

In a first aspect, the present invention relates in particular to a method for determining a target operating variable of an internal combustion engine of a vehicle, wherein the target operating variable is selected according to a target operating variable limit, Is smaller than the target operating variable limit, the value of the emission characteristic variable of the internal combustion engine is determined to be smaller than the preset exhaust limit value. The preset discharge limit value is for example the number of soot particles or the amount of nitrogen oxides. This emission limit value can be standardized in the vehicle, for example, according to the distance traveled by the vehicle. The emission characteristic variable represents the actual emission value of the internal combustion engine, for example the number of soot particles or the amount of nitrogen oxide, likewise (if any). The emission characteristic parameter can be measured, for example. It is also possible, for example, that the emission characteristic variable is calculated from the model. This has the advantage that in operation of the internal combustion engine, for example, an emission limit value that should not be exceeded or exceeded due to legal requirements is maintained, and operation of the internal combustion engine is controlled such that, when the emission limit value is not exceeded, It remains unaffected by the limit value (and can be formed, for example, by optimizing fuel consumption). In particular, the method allows the emission limit to be maintained even in abnormal operation.

In this case, the actual value of the operating variable of the internal combustion engine is set such that, for example, through control, the operating variable of the internal combustion engine actually corresponds to the target operating variable of the internal combustion engine. It is known to those skilled in the art that the actual value may not exactly correspond to the target value, i. E., The target operating variable of the internal combustion engine, especially during the transition behavior. The operating parameters of the internal combustion engine may be provided via, for example, torque or power, or other variables indicative of the torque or output of the internal combustion engine, for example, the amount of fuel injected.

According to another aspect, the target operating parameter limit includes an absolute value threshold or a slope limit value. In this way, as desired, the operating region or dynamics of the internal combustion engine is limited to the discharge non-regime region, i.e. the quasi-normal operation of the internal combustion engine, for example.

For example, if the absolute value of the target operating variable is less than the absolute value limit value, then the value of the emission characteristic variable is less than the preset discharge threshold value And / or if the absolute value of the target operating variable is greater than the absolute value threshold, then the value of the emission characteristic variable may be greater than the preset exhaust threshold value. If the target operating variable limit is given by an absolute value limit value, for example, if the absolute value of the target operating variable is less than the absolute value limit value, then the value of the emission characteristic variable may be less than the preset exhaust limit value , And / or if the absolute value of the target operating variable is greater than the absolute value threshold, the value of the emission characteristic variable may be greater than the preset exhaust threshold value.

Similarly, for example, in the case where the target operating variable limit includes a slope limit value, when the slope of the target operating variable, that is, the temporal change rate, is smaller than the slope limit value, And / or the slope of the target operating variable is greater than the slope limit, then the value of the emission characteristic variable may be greater than the preset discharge threshold value. For example, if the slope of the target operating variable is less than the slope limit, then the value of the emission characteristic variable may be less than the preset discharge threshold value and / Or if the slope of the target operating variable is greater than the slope limit, the value of the emission characteristic variable may be greater than the preset discharge threshold value.

It is also possible that the target operating parameter limit includes more than one value. Such a plurality of values corresponds to a Pareto front, for example.

According to another aspect, the target operating variable of the other drive unit can be selected according to the target operating variable of the internal combustion engine.

This has the advantage that the other drive units can compensate for the changes caused through the limitation of the target operating parameters, as the case may be, in the behavior of the internal combustion engine. In this case, the other operating unit may be provided, for example, via a motor-operable electric machine, or may be provided, for example, via a hydraulic or pneumatic drive unit.

The actual value of the operating variable of the other drive unit is, for example, set via control, to correspond to the actual operating variable of the other drive unit. It is known to those skilled in the art, in particular, that the actual value at the transition behavior does not exactly correspond to the target value, i. E., The target operating variable of the other drive unit.

The operating parameters of the other drive units may be given through, for example, torque or output, or other variables indicative of the torque or output of the other drive unit.

According to an improved aspect, the target operating variable of the other drive unit is set such that the sum of the settable total target operating variable, i.e. the target operating variable of the internal combustion engine, and the target operating variable of the other drive unit, Can be selected to be the same. The driver demand actuation variable can be selected according to the position of the setting member, particularly the accelerator pedal, and thus can be preset directly by the driver. However, it may also be subject to the presetting of another device, for example a cruise control using distance control.

This has the advantage that the driver's demand is the highest priority, i.e. the internal combustion engine and the other drive unit are operated to set the driver's demand. That is, it is also possible that the system is operated such that, for example, the dynamic demand of the driver is limited by the limits of the overall system, rather than by a preset discharge threshold value. Within the scope of the setting of the driver's request, the operation of the internal combustion engine and other drive units can be performed, for example, with fuel consumption optimized.

In particular, the target operating parameter limit may be selected according to which maximum actual value of the operating variable of the other drive unit can be set. This maximum actual value can be, for example, variable and can depend on the operating parameters of the other drive units, and can be determined therefrom, for example, via a characteristic map. In this way, and particularly simply, it can be ensured that the demands on the drive torque, in particular the driver's demand, are reliably implemented.

According to another aspect, the target operating parameter limit may be selected such that the value of the target operating variable of the other drive unit is not greater than the settable maximum actual value of the operating variable of the other drive unit. This ensures, in a particularly simple manner, that a too high demand for another drive unit is not set.

In another aspect, the target operating variable of the internal combustion engine is determined based on the state variable of the drive train, that is, the target value of the operating variable irrespective of the emission, which is determined independently of the emission limit value, As shown in FIG. The drive train includes at least an internal combustion engine and another drive unit.

In this way, the maintenance of the emission limit value can be particularly easily ensured. Only minimal requirements are required to implement the existing control of the internal combustion engine so that the maintenance of the emission limit value is ensured. If the target value of the operating variable irrespective of emission is determined to be an optimization according to a criterion, the optimization point for the criterion can of course be extinguished again through the provided limitations. However, since this effect is often insignificant in the test, it has been proven that the action is meaningless.

This limitation may be provided in particular when the target operating variable limit is given by means of an absolute value limit and if the target value which is independent of discharge is greater than the absolute value limit value, Value thresholds. If the target operating variable limit is given by the slope limit value, for example, the change in the target operating variable limit can be defined by the slope limit value. If the target operating variable limit includes a plurality of variables, correspondingly each target value of the plurality of variables is defined by the assigned limit value, respectively.

According to another aspect, the target operating variable of the internal combustion engine can be determined through maximizing or minimizing the cost function. This procedure has the advantage that it is actually selected for optimization under the operating points allowed for emissions.

In an improved embodiment, the emission cost term can be determined and the cost function is determined according to the emission cost term. This conversion ensures a particularly simple and flexible maintenance of the preset discharge threshold value. In this case, the emission cost term is given through the characteristic map, which provides an estimate of the emission predicted, for example, for each value of the target operating variable, for example the multiplication or addition of a cost function To allow the preset discharge limit value to be maintained when maximizing or minimizing the cost function.

According to another aspect, the emission cost term may be selected according to the target operating parameter limit value. This allows a particularly simple implementation of the emission cost term. If the target operating parameter limit includes an absolute value threshold or a slope limit value, for example, the target operating variable limit may be selected according to the emission limit value.

In another aspect, the invention is directed to a computer program for performing all of the steps of one of the methods described above.

In another aspect, the invention relates to an electronic memory medium in which the computer program is stored.

In another aspect, the present invention relates to a control device comprising the electronic memory medium.

Hereinafter, a preferred embodiment of the present invention is shown.

1 is a block diagram of a schematic topology of a hybrid drive train.
2 is a flowchart according to the first embodiment.
3 is a flow chart according to the second embodiment.
4 is a flowchart according to the first embodiment.

1 shows an electric motor 20 showing an example of a drive train including an internal combustion engine 10 and another drive unit. Of course, a topology with two or more units is also possible.

The electronic control unit 30 also controls the internal combustion engine 10 and, optionally, the electric machine 20. Of course, it is also possible that the electric machine 20 is controlled by a separate control device. The method according to the invention is carried out on the control device 30, for example.

Fig. 2 shows a first embodiment of the present invention. Torque is typically used as an operating parameter. As discussed above, other variables are possible instead of torque. For example, a driver request FW determined by an accelerator pedal sensor (not shown) is transmitted to the first block 300, the second block 310, and optionally the third block 320. The first block 300 is also fed with a maximum settable limit Lim_EM by means of the electric machine 20, which can for example be obtained from the characteristic map, Lt; / RTI > The maximum limitable torque Lim_EM is selectively transmitted to the fourth block 330 by the electric machine 20. [

Alternatively, for example, the current state of charge (SOC) of the battery (not shown) supplied therefrom to the electrical machine is likewise transferred to block 300. [ The actual-torque M_ist_ICE of the currently-applied internal combustion engine 10 is transmitted to the first block 300 and the second block 310.

The first block 300 determines, for example, the distribution of torque (M_ICE_EM) derived from the driver's request (FW) and applied as a whole from the variables transmitted in the first block. From the possible distribution of the torque applied to the internal combustion engine 10 and the electric machine 20 as a whole, the most efficient distribution from the first block 300, for example, for fuel consumption, . The distribution M_ICE_EM may correspond to, for example, a percentage which indicates which part of the overall applied torque is applied by the internal combustion engine 10. [ In this case, the variable sent to the first block 300 represents the state of the drive train and is understood as an example variable for determining the distribution (M_ICE_EM). Other variables are of course possible.

The distribution (M_ICE_EM) is sent to the third block 320. The third block 320 adjusts the optimal distribution (M_ICE_EM) determined by the first block 300. That is, it is determined whether there is a need for heating other needs, for example a catalytic converter (not shown). (M_pre_ICE) of the torque set by the internal combustion engine (10) and the target value (M_pre_ICE) independent of the discharge from the optimum distribution (M_ICE_EM), the driver's request (FW) The target value M_pre_EM that is not related to the discharge is determined. In this case, the term " non-emission related "is understood to mean that an explicit consideration of the value of the emission characteristic of the internal combustion engine 10 is not incorporated into the target value. Further, the target value is determined regardless of the preset discharge limit value ELim.

The target value M_pre_ICE of the torque set by the internal combustion engine 10 and the target value M_pre_EM independent of the discharge of the torque set by the electric machine 20 are transmitted to the fourth block 330 do.

The second block 310 stores the driver demand FW and optionally the rotational speed n of the internal combustion engine 10, the current torque M_ist_ICE of the internal combustion engine 10, the temperature TCat of the catalytic converter, 10) (for example, applied to the cylinder head) is transmitted. The second block 310 determines the current operating point of the internal combustion engine from the parameters, for example the ensemble of parameters defining the operating point. Other variables are available for the determination of the current operating point. Also within the second block 310, a preset discharge threshold value ELim is determined or stored there (e.g., in a storage register).

The second block 310 is set by the internal combustion engine 10 for the current operating point of the internal combustion engine 10 such that the discharge of the internal combustion engine 10 does not exceed the preset discharge threshold value ELim That is, the absolute limit value (AbsLim) of the torque or the maximum possible time change rate, that is, the slope limit value GradLim of the torque. In this case, it is possible that the absolute limit value AbsLim and / or the slope limit value GradLim include not only a positive value but also a negative value, that is, a maximum value and a minimum value.

The second block 310 transmits an absolute limit value AbsLim and a slope limit value GradLim to the fourth block 330. [ The fourth block defines the target value M_pre_ICE of the torque of the internal combustion engine 10 that is not related to the discharge to the absolute limit value AbsLim or the rate of change with respect to the slope limit value GradLim, (M_soll_ICE) of the torque of the internal combustion engine 10 implemented using open-loop control and / or closed-loop control.

Here, the possible reduction of the target value of the torque of the internal combustion engine 10 from the non-discharge-related target value M_pre_ICE to the target value M_soll_ICE corresponds to the target value M_pre_EM, Lt; RTI ID = 0.0 > M_soll_EM < / RTI > It is possible that this target value M_soll_EM of the torque of the electric machine 20 can not be so set because this target value exceeds a maximum limitable limit Lim_EM for example by the electric machine 20 to be. In this case, it is possible to give a higher priority to the threshold value determined by the second block 310 or lower the target value M_soll_ICE of the torque of the internal combustion engine 10. [ However, the target value M_soll_EM of the torque of the electric machine 20 is increased such that the target value M_soll_EM does not exceed the maximum settable torque Lim_EM, and the torque is the sum of the two target values M_soll_ICE and M_soll_EM Decreases the target value M_soll_ICE of the torque of the internal combustion engine 10 to a degree corresponding to the total torque corresponding to the driver demand FW.

Figure 3 shows another embodiment of the present invention. The driver demand FW, the number of rotations n of the internal combustion engine 10 and the state of charge of the battery SOC are transferred to the fifth block 400. [ The block 400 performs the optimization and determines the target value M_soll_ICE of the torque of the internal combustion engine 10 and the target value M_soll_EM of the torque of the electric machine 20 based on the input variable. At block 400 the maximization or minimization of the cost function is performed and the cost function is calculated as a function of the operating parameters of the internal combustion engine 10 and optionally the electric machine 20, Maps consumption.

The sixth block 410 similarly receives the rotational speed n of the internal combustion engine 10, the current torque M_ist_ICE of the internal combustion engine 10, the temperature TCAT of the catalytic converter and the temperature T of the internal combustion engine . Block 410 determines the emission cost term (E_cost) from the variables. The emission cost term E_cost is sent to the fifth block 400 and is a characteristic map that determines an estimate of the emission characteristic variable, for example, in accordance with the operating parameters of the internal combustion engine 10. [

Similarly, a preset discharge threshold value (ELim) is transmitted to the fifth block (400). The fifth block 400 may be implemented in a known manner (e.g., from the emission cost term E_cost and the emission threshold value ELim from the emission threshold value ELim and the emission cost term E_cost) The target value M_soll_ICE of the torque of the internal combustion engine 10 and the target value M_soll_ICE of the torque of the electric machine 20 are obtained through optimization by the inequality addition condition (the emission cost term E_cost should not exceed the emission threshold value ELim) The target value M_soll_EM of the torque of the engine 10 can be determined.

Fig. 4 shows a third embodiment of the present invention. The seventh block 510 determines the target value M_soll_ICE of the torque of the internal combustion engine 10 and the target value M_soll_EM of the torque of the electric machine 20 (again through optimization).

The eighth block 520 is controlled by the internal combustion engine 10 according to the current torque M_ist_ICE of the internal combustion engine 10 according to the presettable emission threshold value ELim and optionally the number of revolutions n of the internal combustion engine 10. [ The absolute value limit value AbsLim of the torque M of the internal combustion engine 10 is determined according to the temperature T of the catalytic converter 10 and the temperature TCat of the catalytic converter.

The ninth block 530 determines the torque of the internal combustion engine 10 in accordance with the optional parameter, the number of revolutions n of the internal combustion engine 10, the temperature T of the internal combustion engine 10, The gradient limit value GradLim of the magnetic field M is determined.

The absolute limit value AbsLim and the slope limit value GradLim are transmitted to the tenth block 540 and optionally the number of rotations n of the internal combustion engine 10 is also transmitted. The tenth block determines a corresponding cost function (AbsCost and GradCost), which is transmitted from the absolute threshold value AbsLim not exceeded and the slope limit value GradLim to the seventh block 510 (e.g., as a characteristic map) do. AbsCost and GradCost ensure the maintenance of the inequality addition condition when optimizing the cost function in the seventh block 510. [

The optimized cost function in seventh block 510 is given as the sum of the cost function (ICE_cost) of the internal combustion engine and the cost function (EM_cost) of the electric machine, for example.

It will be appreciated by those of ordinary skill in the art that the components and signals described above may be implemented entirely in hardware, but also partially in hardware and partially in software.

Claims (15)

A method for determining a target operating variable (M_soll_ICE) of an internal combustion engine (10), wherein a target operating variable (M_soll_ICE) is selected according to a target operating variable limit value (AbsLim, GradLim)
Characterized in that the target operating variable limit value (AbsLim, GradLim) is determined so that the value of the emission characteristic variable of the internal combustion engine (10) is smaller than the preset emission limit value (ELim) Way. The method of claim 1, wherein the target operating parameter limit includes an absolute value limit (AbsLim) or a slope limit value (GradLim). 3. The method according to claim 1 or 2, wherein the target operating variable (M_soll_EM) of the other drive unit (20) is selected according to the target operating variable (M_soll_ICE) of the internal combustion engine (10). 4. A method as claimed in claim 3, wherein the target operating variable (M_soll_EM) of the other drive unit (20) is selected such that the pre-settable overall target operating variable is selected to be equal to the driver requested operating variable . 4. The method according to claim 3, wherein the target operating variable limits (AbsLim, GradLim) are selected based on which maximum actual value (Lim_EM) of the operating variables of the other drive units (20) Way. The method according to claim 5, characterized in that the target operating variable limit value (AbsLim, GradLim) is set such that the value of the target operating variable (M_soll_EM) of the other driving unit (20) Lim_EM). ≪ / RTI > 3. The method according to claim 1 or 2, wherein the target operating variable (M_soll_ICE) of the internal combustion engine (10) is determined based on an operating variable of the internal combustion engine (10), which is determined according to a state variable (Lim_EM, SOC, n, M_ist_ICE) (AbsLim, GradLim) of the internal combustion engine (10), the target value being independent of the emission of the engine (M_pre_ICE). 3. The method according to claim 1 or 2, wherein the target operating variable (M_soll_ICE) of the internal combustion engine (10) is determined through maximizing or minimizing a cost function. The method according to claim 8, wherein the emission cost terms (E_cost, Abs_cost, Grad_cost) are determined and the cost function is determined according to an emission cost term (E_cost, Abs_cost, Grad_cost). 10. The method of claim 9, wherein the emission cost term (Abs_cost, Grad_cost) is selected according to a target operating variable limit value (AbsLim, Gradlim). 3. The method according to claim 2, wherein the absolute value limit (AbsLim) is determined according to a preset discharge threshold value (ELim). 3. The method according to claim 2, wherein the slope limit value (Gradlim) is selected according to an emission limit value. A computer program stored on an electronic memory medium and configured to execute all steps of a method according to any one of claims 1 or 2. 14. An electronic memory medium having stored thereon a computer program according to claim 13. A control device (1) mounted for carrying out all the steps of the method according to claim 1 or 2.

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