DE10058355A1 - Method and device for controlling the drive unit of a vehicle - Google Patents

Abstract

A method and a device for controlling the drive unit of a vehicle are proposed. In this case, at least one manipulated variable of the drive unit is set as a function of a target variable for an output variable of the drive unit and a target actuating time, which represents the time within which the target variable for the output variable must be realized.

Description

State of the art

The invention relates to a method and a device to control the drive unit of a vehicle.

With modern vehicle controls act on the existing ones Actuators (e.g. drive unit, transmission, etc.) one Variety of partly contradicting specifications. So at for example, the drive unit of a vehicle on the Ba sis a driving request specified by the driver, setpoints of external and / or internal regulation and control functions, such as traction control, a Mo Torque control, a transmission control, one Speed and / or speed limit and / or one Idle speed control can be controlled. This Sollvorga ben show partly opposite effects, so that since the drive unit only enters a setpoint can set, these setpoint specifications must be coordinated sen, d. H. select a setpoint to be implemented or to be determined.

It is related to the control of a drive unit such a coordination ver from DE 197 39 567 A1  different target torque values are known. There by Ma ximal and / or minimum value selection from the torque setpoint setpoints for the control paths of the drive unit selects that in the current operating state by determining the Sizes of the individual control parameters of the drive unit, for example, the filling of an internal combustion engine, the Ignition angle and / or the amount of fuel to be injected, will be realized. Boundary conditions of setting the target values are not taken into account.

Advantages of the invention

The definition of a requirement of the drive unit as Target output variable / actuating time value pair results from the Coordination of different requirements an independence of motor-specific adjustment paths. The interface definition tion as the target output variable / actuating time value pair is suitable therefore regardless of the specific type of drive for everyone Types of drives. Coordinators not engine-specific are therefore without change in different types of An driven, in gasoline engines, diesel engines, electric drives, etc. applicable.

It is particularly advantageous that extensions of the system, d. H. the addition of further target output variables / positioning time Value pairs without structure changes in a simple way become light.

The concrete realization of the requirement (target output variable and positioning time) is then dependent on the current loading drive point on the suitable paths of the drive Ness. By requesting a position independent of the operating point This motor-specific part can have time for each setpoint the control is developed separately from the motor-independent part become.  

By defining the above, abstract and physical The overall structure becomes an interpretable interface the engine control more clearly.

Due to the separation between motor-independent and motor-sp specific components due to the introduction of the target size ß / actuating time interface becomes another degree of freedom created the implementation of the requirement in the motor spec fishing part of the engine control. It will be possible possibilities for the realization of the requirement by ver different paths increased and additional optimization release potential.

Another additional degree of freedom results from the Specification of a continuously variable actuating time for Setpoint, which enables precise specification and implementation of the Interventions in the drive unit is made possible.

By coordinating target size requirements and Positioning time requirements are advantageous different requirements combined, so that to control the drive unit a pair of requirements (each with respect to Positioning time and setpoint) is provided.

Further advantages result from the following Be writing of exemplary embodiments or from the dependent ones Claims.

drawing

The invention is explained below with reference to the embodiments shown in the drawing. Here, FIG. 1 shows an overview diagram of a control device for controlling a drive unit. Fig. 2 shows a flow diagram, which represents a preferred embodiment of the setpoint / actuating time interface. The effect of this interface is outlined using the time diagram of FIG. 5. In FIGS. 3 and 4 and 6 to 9 are flow charts shown which execution preferred examples of the co-ordination of nominal variables / Operating time represent requirements. The time diagram of FIG. 10 shows an example of the mode of operation of the setpoints / actuating time specification and coordination. In Fig. 11, a further embodiment for coordination of target sizes is / parking time requirements shown.

Description of exemplary embodiments

Fig. 1 shows a block diagram of a control device for controlling a drive unit, in particular an internal combustion engine. A control unit 10 is provided which has as components an input circuit 14 , at least a computer unit 16 and an output circuit 18 . A communication system 20 connects these components for mutual data exchange. The input circuit 14 of the control unit 10 are supplied to input lines 22 to 26 , which in a preferred embodiment are designed as a bus system and via which the control unit 10 is supplied with signals which represent operating variables to be evaluated for controlling the drive unit. These signals are detected by measuring devices 28 to 32 . Such operating variables are accelerator pedal position, engine speed, engine load, exhaust gas composition, engine temperature, etc. Via the output circuit 18 , the control unit 10 controls the power of the drive unit. This is symbolized in FIG. 1 on the basis of the output lines 34 , 36 and 38 , via which the fuel mass to be injected, the ignition angle and / or an electrically operable throttle valve for adjusting the air supply to the internal combustion engine be operated. The air supply to the internal combustion engine, the ignition angle of an individual cylinder, the fuel mass to be injected, the injection time and / or the air / fuel ratio, etc. are set via the adjustment paths shown. In addition to the input variables described, there are further control systems of the vehicle which transmit 14 input variables, for example torque setpoint, to the input circuit. Control systems of this type are, for example, traction control systems, vehicle dynamics controls, transmission controls, engine drag torque controls, etc. In addition to the setpoint specifications shown, the external setpoint specifications, which also include a setpoint specification by the driver in the form of a driving request and / or a speed limit, are internal specification variables for controlling the Drive unit available, for example a change in torque of an idle control, a speed limit that outputs a corresponding target variable, a torque limit and / or limits from component protection and / or a separate target variable in the start.

With the individual setpoint values there are boundary conditions or properties related to the way of Represent the implementation of the setpoint values. You can depending on the application example with the setpoint values ei ne or more properties are connected. It has shown that essential information is the actuating time is within which the setpoint is to be set. In addition, other properties of the setpoint specification are transmitted, for example their priority. Under Actuating time is understood to mean the period in which the At least the target size must be set. The course of the Actual size influenced by the target size between the current ellen (start) size and the target size (end size) in the Positioning time is free depending on the chosen objective  determinable. This course can thus be adapted to the engine and according to at least one optimization criterion (e.g. minimal fuel consumption) can be optimized. The actual size esse must only at the time of the operating time, d. H. at Been of the positioning time.

The described specification of target size and actuating time as The pair of values is not only in connection with internal combustion engines like petrol or diesel engines, be it with intake manifolds injection or direct injection, but also in conjunction with other drive concepts, such as electrical motors to use.

As a default size (target size) is in a preferred Aus example given a torque of the drive unit ben. In other applications, you can use default sizes also other output variables of the drive unit such as Lei Performance values, speeds, etc. provided as default values his.

In Fig. 2, a flowchart is shown, which represents the interface shown above and the implementation of the pair of given values in manipulated variables using the example of a simple embodiment. The control unit 10 essentially comprises a coordinator 100 and a converter 102 . In addition to input variables (not shown), for example those mentioned above, setpoint torques MSOLL1 and MSOLL2 as well as the associated actuating times TSOLL1 and TSOLL2 are supplied by external control systems, such as traction control system 104 and driver 106, as input input variables, within which the predetermined setpoint torque is supplied is to be set. These default value pairs are fed to the coordinator 100 . There, one of the following strategies is selected in accordance with, for example, a resulting default value pair MSOLLRES and TSOLLRES, taking into account further default value pairs. This is fed to the converter 102 . In converter 102 , taking into account the current operating state of the drive unit, which takes place on the basis of operating variables such as engine speed, engine load, actual torque, etc. (see symbolic lines 108 to 110 ), the manipulated variables for controlling the air supply, the ignition and / or the fuel injection formed. Tables are provided in an advantageous embodiment for the selection of the respective actuation path, in which, depending on the current operating state of the drive unit, the respective minimum actuation times of the individual actuation paths are entered for a specific torque change. Depending on the specified target actuation time and the intended torque change, the actuation path is selected according to a predefined strategy (e.g. optimal consumption), via which the torque change can be implemented within the target actuation time. If it is not possible to change the torque using only one path, a combination of the control paths is selected to ensure that the target torque is achieved within the specified control time.

In another exemplary embodiment, a further coordinator is provided between the coordinator 100 and the converter 102 , in which the resulting variables of the coordinator 100 , which only concern motor-independent variables, with motor-specific target variables / actuating time value pairs (torque limits, speed limits, etc.) be coordinated accordingly. The output signal is a resultant setpoint torque / actuating time value pair which is supplied to the converter 102 and is converted into the individual actuating variables in accordance with the above illustration.

In FIG. 5, time diagrams are plotted which outline the course of the torque of the drive unit at different times when the desired torque value and the desired actuating time change. Fig. 5a shows the timing of the target torque mode, Fig. 5e of the operating time, while in Fig. 5b to 5d, the course of the actual torque M is applied. The course of the desired torque setting is shown in FIG. 5, wherein said target torque from the time T0 to the time t0 + T increases, up to the time T0 + 2T remains constant. The actuating time remains constant between the times T0 and T0 + T, while it is reduced at the time T0 + 2T. Accordingly, the expected torque curve is shown, which is shown in FIG. 5b at time T0 and in FIG. 5c at time T0 + T. The setpoint actuating time is constant, the setpoint torque value is increased so that the torque curve to be expected is adjusted accordingly. At the point in time T0 + 2T, the setpoint torque value remains constant, but the actuating time is considerably reduced, so that the torque change will be considerably faster. It is essential that the actuating time changes continuously and is adjusted at every point in time. For example, the operating time is always shorter under unchanged conditions and the same torque to ensure that the torque is set after the original operating time.

Various strategies have proven suitable for the coordination of the value pairs in the coordinator 100 or the coordinators provided in the engine control, the minimum coordination, the maximum coordination, the additive coordination, the subtractive coordination, the actuating time-oriented maximum coordination and / or the actuating time-oriented Minimal coordination.

In the flow chart of FIG. 3, an example of the mini mum coordination is shown. This consists in comparing the values of the target torques and selecting the smallest as the result of the target torque. The resulting actuating time is then the actuating time assigned to this moment. With this coordination strategy, the number of pairs of values to be coordinated is unlimited. In addition to the actuating time, other information, such as the priorities assigned to the individual interventions or other information, can be selected in a corresponding manner.

Fig. 3 shows a flow diagram of the minimum coordination coordinator 100th The target torques MSOLL1 and MSOLL2 are fed, which are fed to a comparator 150 . This comparator determines which of the two setpoints is the smallest. Depending on the result, the comparator 150 actuates switching elements 152 or 154 via its output signal, by means of which the smallest torque setpoint is output as the resulting setpoint torque. Furthermore, the actuating times TSOLL1 and TSOLL2 are fed to the coordinator 100 , the comparator 150 switching the switching element 152 in such a way that the actuating time assigned to the smallest moment is output as the resulting actuating time TRES.

Fig. 4 shows a flow chart for the maximum coordination. In the case of maximum coordination, the values of the target torques are also compared, but not the smallest but the largest of the target torques is selected. The resulting actuating time in this case is also the actuating time assigned to the largest moment. Analogous to the minimum coordination, the coordinator 100 for maximum coordination comprises a comparator 160 , to which the target torques MSOLL1 and MSOLL2 are fed and which actuates switching elements 162 and 164 via its output signal. The comparator 160 determines the largest of the supplied moments and switches the switching elements 162 and 164 accordingly. This is done in such a way that the largest torque value is selected as the resultant render target torque value MSOLLRES and the actuating time assigned to the largest torque value is selected as the resultant actuating time TSOLLRES via the switching element 162 .

The minimum coordination is especially with torque reduction decorative interventions, especially with gear shifting handles and traction control interventions applied, weh rend the maximum selection for torque-increasing interventions, such as engaging engine drag torque regulation, application.

It has been shown that the minimum and maximum coordination are not sufficient to cover all conceivable applications. For example, when switching on auxiliary units such as an air conditioning system, the drive unit has to generate additional torque in a relatively short operating time. If this coincides with an increase in the target torque, an uncomfortable torque curve can occur during the maximum or minimum value coordination. It is therefore envisaged that the positioning times and setpoint torques are not coordinated independently of one another, but are linked to one another. In the time diagram of FIG. 6, a coordination strategy is shown, in which nominal torque values are added. With this so-called additive coordination of target torque / actuating time value pairs, the smallest actuating time is first determined. By interpolation, an interpolated setpoint torque is then determined for this setpoint time for the at least one further setpoint / setpoint value pair. The resulting setpoint torque is the sum of the possibly interpolated setpoint torques for the smallest actuating time. The resulting positioning time is the smallest. Depending on the application, a linear, exponential, monotonous or non-monotonous function is provided as the interpolation function. The interpolation takes place on the basis of the actual torque or another torque, for example the last target torque. Here, too, other information can be selected in addition to the actuating time, for example priorities.

In FIG. 6, the moment M is plotted against time, with the coordinate origin of the current time T0 and the current actual torque present MIST represents. The resulting actuating time for setting the target torques is the smallest of the actuating times TSOLLRES, ie T1. In the example shown, two setpoint torques are to be coordinated, namely MSOLL2, to which the actuating time T2 is assigned and MSOLL1, to which the actuating time T1 is assigned. In order not only to meet the implementation of the target torque MSOLL1 but also that of the target torque MSOLL2 when selecting the shortest actuating time, the amount of torque reached at time T1 when the target torque value MSOLL2 is realized is shown on the basis of the interpolation straight line (dashed) in this example MSOLL2 'calculated. This is then added to the setpoint torque value MSOLL1 to be achieved at time T1, the resultant setpoint torque value MSOLLRES being formed by the addition of the two values. The setpoint torque value MSOLLRES is then realized within the time T1, not only the setpoint torque value MSOLL1 assigned to the smallest actuating time but also the value MSOLL2 assigned to the other actuating time being taken into account.

Accordingly, subtractive coordination is planned the z. B. comes into play when switching off consumers, where also the smallest actuating time of the supplied Value pairs is determined. Again, through Interpolati on for the at least one further pair of values this one Time taken, determined by interpolation target mo ment determined. The resulting target torque is then  Difference of the interpolated nominal torques of the smallest Positioning time according to the specified link. The right resulting actuating time is the smallest actuating time. The Inter polation and the consideration of further information, if necessary is done in the same way as additive coordination.

FIG. 7 shows the curve of the torque over time analog to FIG. 6. Here too, the resulting actuating time T1. The setpoint torque to be realized with this actuating time is MSOLL1. The setpoint torque interpolated for the time T1 for the pair of values MSOLL2 / T2 is then subtracted from MSOLL1, resulting in the resulting setpoint torque MSOLLRES, which is ultimately set in the setpoint setting time T1.

Another option for linking the value pairs is the positioning-based maximum or minimum selection. This represents an alternative to the coordination according to FIGS. 3 and 4, the difference being that in principle the smallest actuating time of the transmitted desired torque / actuating time value pairs is selected, while in the solution of FIGS. 3 and 4 always that selected actuating time is selected. As a result, the dynamic conditions are better taken into account. Interpolation is used to determine pairs of interpolated setpoint torques for the other values for this actuating time, as mentioned above. The resulting setpoint torque is then the smallest (minimum) or the largest (maximum) of the setpoint torques at the time of the smallest actuating time. The resulting actuating time is the smallest actuating time. Here, too, the interpolation takes place and additional information is taken into account in accordance with the above.

This coordination strategy is outlined using the time diagrams of FIGS. 8 and 9. The torque is plotted over time there. The positioning time is T1 as the smallest of the supplied positioning times. According to FIG. 8, the setpoint torque associated with the actuating time T1 is MSOLL1 and the MSOLL2 associated with the actuating time T2. A setpoint torque value is calculated from the pair of values MSOLL2 / T2 at time T1 by means of interpolation, which is then linked to the setpoint MSOLL1 in a maximum value selection. Since in the example shown this value is smaller than the value MSOLL1, the resulting setpoint torque value MSOLLRES is the value MSOLL1. The setpoint MSOLL1 is thus realized within the time T1. In Fig. 9, the corresponding procedure is shown as minimum selection. Here too, the shortest actuating time is T1. The setpoint MSOLL1 is assigned to this. The other pair of values is MSOLL2 and T2. The interpolation gives a setpoint torque value at the time T1 from this pair of values, which is smaller than the setpoint value MSOLL1. Based on the minimum selection, the interpolated setpoint is output as the resulting setpoint MSOLLRES and set within the actuating time TSOLLRES.

The mode of operation of the above-described specification of target torque / actuating time value pairs and their coordination is shown in FIG. 10 using an exemplary selected operating situation using a minimum coordination. Here, Figures 10a 10b and 10c shows ments. The time course of the actual torque of the drive unit, Fig. Sollmo of the. To the desired setting time. First of all, the driver's request is the dominant element. The driver specifies a target torque value MSOLL, to which a positioning time TSOLL is assigned and which is realized by a corresponding increase in torque according to FIG. 10a. A traction control system intervenes at time T1. Because of its smaller target torque, a smaller target torque is suddenly specified at time T1, to which a significantly shorter actuating time is assigned due to the necessary dynamics of the intervention according to FIG. 10c (time T1). Therefore, the actual torque is reduced to the target torque very quickly from time T1. Since the setpoint torque remains unchanged until time T2, there is no longer any change in torque with the actuating time unchanged. At time T2, the traction slip control is terminated, the setpoint torque is set again to the driver's request (the setpoint torque of the controller is again greater than that of the driver's request). The longer actuating time is assigned to the resulting moment. Depending on the current operating state at time T2, which occurs in the period between T1 and T2 depending on the selected adjustment paths, there is either a slow change taking into account the large positioning time or the very fast change until time T2, which then occurs changes to a slower one (cf. FIG. 10a). This occurs e.g. B. with long-term ASR intervention (on driving on snow), since in this case the air filling path is withdrawn stationary and a rapid increase may not occur due to a lack of reserve over the Zündwin angle. Furthermore, with existing reserves, other operating conditions and requirements (e.g. comfort, heating, component protection) can play a role in deciding whether to climb quickly or slowly.

FIG. 11 shows a further exemplary embodiment of the coordination of two pairs of setpoints and actuating times based on an interpolation. Furthermore, the predicted size of the target size of the two interventions is also taken into account in the coordination. This predicted variable represents the target variable that is likely to be available in the future (e.g. during an intervention in a traction control system, the predicted variable is the target variable specified by the driver). The coordinator shown in FIG. 11 is therefore supplied with a first setpoint (preferably setpoint torque) Msoll1, a first actuating time specification tsoll1 and a predicted variable Mpräd1 of the setpoint assigned to these values. From a second intervention, target variable Msoll2, actuating time tsoll2 and predicted variable Mpräd2 are supplied. The two predicted variables Mpräd1 and Mpräd2 are guided to a minimum selection level 200 . The smaller of the two values represents the resulting predicted variable Mprädres, which is taken into account in the implementation in the converter 102 (for example when determining the setpoint for the filling (air supply) for the internal combustion engine).

Like the setpoint values Msoll1 and Msoll2, the two actuating time values tsoll1 and tsoll2 are supplied to switching elements 202 and 204 , respectively, which switch from the position shown to the other position as a function of a switching signal. Depending on the position of these switching elements, either the first (Msoll1, tsoll1) or the second pair of values (Msoll2, tsoll2) is passed on to the controller of the drive unit as the resulting pair of values (Msollres, tsollres).

The switching signal for the switchover is derived from the two value pairs by interpolating the setpoint values between the associated actuating time and the minimum actuating time. The two actuating time values Tsoll1 and Tsoll2 are led to a minimum value selection stage 205 , in which the minimum actuating time value is determined as the smaller of the two values. The minimum actuating time value is supplied to division stages 206 and 208 , in which the quotient between the minimum actuating time value and the respective target actuating time Tsoll1 or tsoll2 is formed (tsollmin / tsoll1 or tsollmin / tsoll2). In each case a multiplication point 210 or 212 , the respective quotient is multiplied by the associated setpoint value Msoll1 or Msoll2 ( 210 : Msoll1.tsollmin / tsoll1; 212 : Msoll2.tsollmin / tsoll2). The two setpoint values evaluated in this way are then compared with one another in a comparator 214 . If the result of stage 210 is greater than that of stage 212 , the switching elements 202 and 204 are switched such that the pair of values Msoll1 and tsoll1 are passed on as the resulting variables, while in the opposite case the variables Msoll2 and tsoll2 are passed on.

To determine the resulting pair of values, the Determined setpoint that (provided linearity) to The smallest actuating time must exist (in Terpolated setpoint at the time of the smallest digit time). The largest of the setpoint values determined in this way is determined then the resulting pair of values. The latter is the largest interpolated target size associated original who tepaar.

As in the case of the exemplary embodiment in FIG. 11, a torque variable is preferably used as the target variable, but in other applications the power, the rotational speed, etc., instead of a torque.

Claims (11)

1. A method for controlling the drive unit of a vehicle, wherein at least one manipulated variable of the drive unit is set as a function of a preset variable for an output variable from the drive unit, characterized in that a manipulated time variable is specified together with the preset variable, within which the preset variable is set must become. 2. The method according to claim 1, characterized in that from several pairs of values of the setpoint and the setpoint time a resulting setpoint and a resulting Actuating time is selected that corresponds to the setting of the actu size is taken as a basis. 3. The method according to any one of the preceding claims, since characterized by that the smallest setpoint value and the associated actuating time as the resulting pair of values is selected. 4. The method according to any one of the preceding claims characterized by that as the resulting pair of values the largest setpoint and the actuating time assigned to it is selected.   5. The method according to any one of the preceding claims characterized by that as the resulting pair of values the smallest actuating time and the sum of this actuating time assigned target size and one based on the Target size of the at least one other value pair for Time of the actuating time interpolated setpoint is formed becomes. 6. The method according to any one of the preceding claims, since characterized by that as the resulting actuating time the smallest actuating time and as the resulting setpoint a target size is selected from the smallest Actuating time assigned target size and one on the basis the at least one other pair of values formed size is formed at the time of the actuating time. 7. The method according to any one of the preceding claims characterized by that as the resulting actuating time the smallest actuating time and as the resulting setpoint the smallest or the largest target size at the time of smallest actuating time is formed. 8. The method according to any one of the preceding claims characterized by that the positioning time is continuous is changeable. 9. The method according to any one of the preceding claims, since characterized by that as the resulting quantities Value pair is passed on, at which the interpo at the time of the smallest actuating time on greatest is. 10. The method according to any one of the preceding claims characterized by that a predicted target size is provided, with the resultant predicted target  size the smallest of the coordinated predicted target sizes is determined. 11. Device for controlling the drive unit of a drive stuff, with a control unit, which at least one Actuating variable of the drive unit depending on an input size for an output size of the drive unit provides, characterized in that means for setting tion of the manipulated variable are provided as the default variable a setpoint for the output size and a setpoint get time within which to set the target size is.