Title of Invention

METHOD AND DEVICE FOR CONTROLLING THE DRIVE UNIT OF A VEHICLE

Abstract

The present invention relates to method and a device for controlling the drive unit of a vehicle are provided, setpoint variables and characteristic variables being received, which represent the way the setpoint selection variable is set. In a coordinator, setpoint selection variables and characteristic variables are coordinated independently from one another and one of the variables is selected, on which the control of the drive unit is based. In a convertor, the selected setpoint selection variable and characteristic variable are converted into control signals, the control signals being selected on the basis of the setpoint selection variable and the characteristic variable, optionally considering further operating variables, for example, the operating states of the drive unit.

Full Text

The invention relates to a method and a device for controlling the drive unit of a vehicle. BACKGROUND OF THE INVENTION In modern vehicle controllers, a multiplicity of, in certain cases contradictory, predefined values act on the actuator elements present (for example derive units, transmission etc.). The intention here is, for example, to control the drive unit of a vehicle on the basis of a driver"s request predefined by the driver, setpoint values of external and/or internal adjustment and control functions, for example a traction controller, an engine torque controller, a transmission controller, a rotational speed and/or travel speed limiter and/or an idling speed controller. These predefined values have in certain cases opposed effects so that, since the drive unit can only set one of these predefined setpoint values these predefined setpoint values have to be coordinated, i.e, a predefined setpoint value which is to be implemented has to be selected, German publication DE 196 11 502 Al discloses a method and a device for controlling the vehicle speed using a vehicle speed control. The vehicle speed control depends on the driver behaviour. The driver behaviour is determined by a driver characteristic value of an automatic transmission control. Document Dl discloses the variation of constant values of the vehicle speed control in dependence of the driver characteristic. The means that the dynamic of the vehicle speed control is increased by increasing the constant values for a speed oriented driver whereas for an economic driver lower control values are selected. US 5,491,635 discloses only the relationship between a vehicle control, an environment of the vehicle and a driver behaviour is described without taking into account different property variable for different desired values and without taking into account an independent coordination of desired values and of property variables. In connection with the control of a drive unit, DE 197 39 567 AI discloses such coordination of various setpoint torque values. Here, by means of the selection of maximum and/or minimum values from the setpoint torque values, a setpoint value is selected which is implemented during the operating state at the particular time by determining the variables of the individual control parameters of the drive unit, for example, in the case of an internal combustion engine ~ - the fuel charge, the ignition angle and/or the fuel quantity to be injected. In addition to the variables of the predefined setpoint values, it is possible for various properties, for example relating to the necessary dynamics of the setting, of the priority etc., to be associated with the predefined setpoint values, it being also possible that said properties are of contradictory nature and are not taken into account in the known coordination of the predefined setpoint variables. DE 197 09 317 Al discloses a procedure in which coordinators which perform the resource demand and the resource distribution of the control systems of an entire vehicle, inter alia on the basis of communicated peripheral conditions, for example, a desired dynamic, are predefined for the entire vehicle. Specific information on the procedure for controlling a drive unit regarding the abovementioned properties of the predefined setpoint values are not given. The object of the invention is to specify measures with which, in addition to the predefined setpoint value variables, the property variables that are associated with them are also coordinated and/or taken into account in the conversion into control variables for controlling the drive unit. This is achieved by means of the features of the independent patent claims. Advantages of the invention By means of the mutually independent coordination of the property variables and of the predefined setpoint value variables, optimum coordination of contradictory requirements made of the control of the drive unit is implemented and in each case a suitable setpoint variable with a selected property variable or selected property variables is converted into the corresponding control parameters of the drive unit. The result is a satisfactory implementation of the predefined setpoint variables within the scope of the peripheral conditions transmitted with the predefined setpoint values. It is particularly advantageous that in this way the aforesaid variables are coordinated without the specific selection of the control parameters of the drive unit (for example fuel charge, ignition angle, injection quantity, injection time, etc. in the case of an internal combustion engine) having to be made as early as the time when the predefined setpoint value variables and their property variables are coordinated. The procedure presented for coordinating and/or converting predefined setpoint value variables and property variables is used particularly advantageously in direct petrol injection systems but also in conventional intake manifold injection systems, diesel injection systems or with alternative drive concepts (electric drives, fuel cell drives, etc.). In a torque-oriented control system for the drive unit, all the external and internal torque requests are advantageously coordinated and prioritized with the inclusion of their transmitted peripheral conditions. Here, it is particularly advantageous to coordinate different dynamic requirements using the presented procedure, taking into account limits of the dynamic conversion by the coordinator. These coordinators can also be distributed over a plurality of controllers, independently of the partitioning. The resulting setpoint value which is determined by the coordinator is advantageously converted, together with the resulting property variable or variables by means of one or more setpoint values for the actuation paths (control variables) of the drive unit as a function of the operating point and operating state of the drive unit. In the conversion and selection of the available actuation paths, the transmitted property variable or variables and the current operating state of the drive unit are taken into account so that optimum conversion of the resulting predefined setpoint value is carried out within the framework of the resulting property or properties and of the operating state of the engine at that particular time. Further advantages emerge from the following description of exemplary embodiments and from the dependent patent claims. Drawing The invention is explained in more detail below with reference to the embodiments illustrated in the drawing. Here, Figure 1 is an overview circuit diagram of a control device for controlling a drive unit in a preferred exemplary embodiment, while Figures 2 to 4 are flowcharts which represent the coordination of the existing predefined setpoint values together with properties, and the conversion of the resulting predefined setpoint value and property or properties by selecting the available actuation paths. Description of exemplary embodiments Figure 1 shows a block circuit diagram of a control device for controlling a drive unit, in particular an internal combustion engine, preferably with direct petrol injection. A control unit 10 is provided which has, as components, an input circuit 14, at least one computer unit 16 and an output circuit 18. A communication system 20 connects these components for the mutual exchange of data. The input circuit 14 of the control unit 10 is supplied with input lines 22 to 26 which are embodied in one preferred exemplary embodiment as a bus system and via which the control unit 10 is supplied with signals which represent operating variables which are to be evaluated for the control of the drive unit. These signals are sensed by measuring devices 28 to 32. Such operating variables are the accelerator pedal position, engine speed, engine load, exhaust gas composition, engine temperature, etc. The control unit 10 controls the power of the drive unit via the output circuit 18. This is symbolized in Figure ± by means of the output lines 34, 36, and 38 via which at least the fuel mass to be injected, the ignition angle of the internal combustion engine and at least one throttle valve which can be actuated electrically in order to set the supply of air to the internal combustion engine are activated. In addition to the input variables described, further control systems of the vehicle are provided which transmit predefined variables, for example, torque setpoint value, to the input circuit 14. Such control systems are, for example, traction controllers, vehicle movement dynamic controllers, transmission controllers, engine torque controllers, etc. The supply of air to the internal combustion engine, the ignition angle of the individual cylinders, the fuel mass to be injected, the injection time, the fuel/air ratio, etc. are set by means of the actuation paths illustrated. In addition to the predefined setpoint values represented, the external predefined setpoint values, which also include a predefined setpoint value by the driver in the form of driver"s request, internal predefined variables for controlling the drive unit are present, for example a change in torque of an idling controller, a rotational speed limiter which outputs a corresponding predefined setpoint variable, a limiter which limits the change in the traveling speed and/or the torque, limitations owing to the need to protect components or a separate predefined setpoint variable when starting. Peripheral conditions or properties which represent the method of conversion of the predefined setpoint value variable are associated with the individual predefined setpoint value variables. Here, depending on the application, one or more properties may be connected to one predefined setpoint value variable so that, in one advantageous exemplary embodiment, the term properties may include a property vector in which the various property variables are entered. Properties of predefined setpoint value variables are, for example, the necessary dynamics when setting the predefined setpoint value variable, the priority of the predefined setpoint value variable, the magnitude of the reserve torque to be set and/or the comfort of the adjustment (for example change limitation). These properties are present in one preferred exemplary embodiment. In other exemplary embodiments, more or fewer, or even only one property is present. A corresponding property vector which comprises the properties presented above is transmitted with each predefined setpoint value variable by the external control or adjustment devices or the internal functions. Figure 2 shows a flowchart which outlines a program running in the computer unit 16 of the control unit. It describes the coordination and implementation of the predefined setpoint values and their properties. A variable representing the accelerator pedal position P is supplied to the computer unit 16. In a calculation step 100, said computer unit 16 converts said variable, possibly taking into account further operating variables such as the engine speed, into a driver"s desired torque MiFA which is fed to the coordinator 102. In addition, external torque setpoint values Mil to MiN, which are also fed to the coordinator 102, are transmitted to the computer unit 16. The selected properties (or property vectors which are composed of individual property variables) el to eN are transmitted with each torque setpoint value and fed to the coordinator 102. Furthermore, internal functions 110 are provided which either also feed torque setpoint values with the corresponding.property variables to the coordinator 102 or which predefine limiting values Mlim for the torque setpoint values or elimit for the property variables, which are also fed to the coordinator 102 and taken into account in the coordination of the setpoint values and property values. The output of the coordinator 102 is the resulting torque setpoint value MiSETP, which is ultimately supplied for the setting, and the resulting property variable or variables eSETP selected from the supplied property variables taking into account the limiting values, and within the framework of which the setpoint value is implemented. These variables are fed to a converter 104 to which in addition further operating variables such as the engine speed, etc, are fed. The converter converts the setpoint torque value MiSETP into actuation variables taking into account the supplied operating variables and the resulting property variable or variables. Fuel metering, ignition angle, supply of air, etc. are influenced with these actuation variables in such a way that the predefined setpoint torque is set within the framework of the resulting property or properties. Figure 3 shows a flowchart which constitutes a preferred exemplary embodiment of the coordinator 102. As illustrated above, the coordinator is supplied with setpoint torque values Mil to MiN, including also the setpoint torques of the internal functions. These setpoint torques are assigned property variables el to eN, likewise for the internal predefined setpoint values. The setpoint torque values are fed to the torque coordinator 102a which operates as in the afore¬said prior art. The property variables (vectors) el to eN are fed to the property coordinator 102b and coordinated there. The specific configuration of the coordinator 102b depends on the properties used. The property ""priority" is selected by the coordinator in that the respective highest priority is transferred to the converter. The property "dynamics" is selected in which the respective maximum dynamics request is output as a property at the converter. The same applies to the property reserve torque. Here, too, the maximum reserve torque to be set is transferred. In terms of the property comfort the selection results, for example, from the fact that depending on the driver type which is set (sporty driver, comfortable driver, etc.) the selection in terms of the property comfort is made for implementation which is more comfortable or more sporty. The predefined setpoint values and properties which are selected in this way are output to the limiter 102c by the coordinators 102a and 102b. At the limiter 102c, the predefined setpoint value is limited to the predefined- torque limiting values Milim, which is [sic] formed for reasons of protecting components, exhaust gas reasons, etc. Correspondingly, the transmitted property value or values is limited to the limiting value egrenz. For example, the [sic] in the current operating state this limited value represents the maximum possible dynamics of the adjustment or the maximum possible magnitude of the torque reserve. The property limiting values are either permanently predefined or calculated on the basis of the operating state, of operating variables etc. within the scope of characteristic diagrams. The possibly limited resulting values MiSETP and eSETP which are transmitted to the converter for setting are then output by the limiter 102c. Setpoint torque values and property values are thus coordinated separately and independently of one another. For this reason, if a setpoint torque value is selected by the coordinator 102, its input properties can be changed because a different property is selected as essential by the coordinator l02b. These property values can accordingly be changed independently of the torque setpoint values. Figure 4 shows a flowchart of a preferred implementation of the converter 104. The resulting values MiSETP and eSETP which are determined according to Figure 3 are fed to the latter. Accordingly, in 104a the actuation paths are selected taking into account, where appropriate, further operating variables which are supplied via the lines 104b to 104c. This is carried out, for example, in accordance with the property which is to be implemented for each actuation path when the set point value or part of the setpoint value is set. For example, the minimum necessary time for setting the setpoint value is specified in a table with respect to the property dynamics as a function of the current operating state which is essentially determined by the rotational speed, with the result that the suitable actuation path is selected taking into account the dynamic request. The actuation variables are therefore generated with reference to the transmitted setpoint values and properties and are dependent on the operating mode (in direct petrol injection engines), rotational speed variables and/or further input variables. If homogeneous operation occurs, for example, the reserve torque is set as an ignition angle adjustment, whereas in the case of the stratified operation operating mode it is not carried out. The information relating to the current operating mode is provided to the converter 104. A further example is the anti-judder function which requests the conversion of a torque request in a specific time, for example 50 ms. This is possible at a low rotational speed only by means of an ignition angle adjustment or by means of a change of the fuel mass flow rate in the case of stratified operation as only these actuation paths make available the necessary dynamics. At high rotational speeds, the requested change is also possible by means of the fuel quantity, and also during homogeneous operation because the dead angles in the fuel path now lead to dead times which are shorter than the necessary dynamics. The converter therefore determines the torque to be set for each individual actuation path. The actuation paths air (ML), ignition angle (MZW) and fuel (MQK) are represented in this context in Figure 4, The implementation of the property eL, eZW, eQK characterizing [lacuna] actuation variable (for example, the necessary dynamics of the adjustment of the respective actuation variable, etc.) is also transmitted with each actuation variable. In a preferred implementation, the necessary dynamics of the adjustment of the torque are transmitted as property variable. In order to select the actuation path or paths, tables are provided in this example in which the minimum adjustment times of the individual actuation paths are entered, as a function of the rotational speed, for a specific change in torque. For a change in torque of 50 Nm, an adjustment time of 67 msec for the air path, 33 msec for the fuel path and 14 msec for the ignition angle path are obtained, for example, for a rotational speed of 2000 rpm, while at 4000 rpm the corresponding values 27 msec, 13 msec and 6 msec are obtained. For this reason, the ignition angle path is selected in the case of a property value of 30 msec with a rotational speed of 2000 rpm, and the air path is selected for a rotational speed of 4 000 rpm. If the change in torque cannot take place solely by means of one path, a combination of the actuation paths is selected (for example a part of the change in torque by means of the ignition angle and the rest by means of the fuel), corresponding property values being transmitted for the respective actuation path. In one exemplary embodiment, after the change in torque the ignition angle is reset to its starting point and the air supply is correspondingly adapted. The other properties are implemented in a corresponding way. A further example is obtained if a reserve is set for X = 1 homogeneous operation by increasing the fuel charge and adjusting the ignition angle in the retarded direction. During stratified operation, the requesting of the reserve either leads to switching of the operating mode (reserve cannot be set) or as a result of the X limits there is already the required reserve during stratified operation. The setpoint actuation variables are then output in the actual converter 104d in accordance with the selection made, also taking into account operating variables which are fed via the lines 104e to 104f, taking into account the transmitted properties, into actuating signals for setting the metering of fuel, the ignition angle and/or the air supply. Here, the transmitted setpoint value is converted, in a fashion known from the prior art, into actuation variables while the method of changing the actuation variable is determined by the properties. The degrees of effectiveness of the pilot-controlled paths are taken into account in accordance with the prior art. In relation to the aforesaid actuation variables, further actuation variables such as injection time, swirl valve setting, valve settings, etc. are available in particular in direct petrol injection engines. The procedure described is not only limited to application in petrol internal combustion engines but is also correspondingly applied in diesel internal combustion engines and/or alternative drive forms such as, for example, electric motors, etc, In addition, the described procedure is used not only in conjunction with the predefinition of torque setpoint values but also with other output variables of the drive unit such as power, rotational speed of the driven shaft etc.

Documents:

in-pct-2002-1092-che abstract-duplicate.pdf

in-pct-2002-1092-che abstract.jpg

in-pct-2002-1092-che abstract.pdf

in-pct-2002-1092-che claims-duplicate.pdf

in-pct-2002-1092-che claims.pdf

in-pct-2002-1092-che correspondnece-others.pdf

in-pct-2002-1092-che correspondnece-po.pdf

in-pct-2002-1092-che description(complete)-duplicate.pdf

in-pct-2002-1092-che description(complete).pdf

in-pct-2002-1092-che drawings-duplicate.pdf

in-pct-2002-1092-che drawings.pdf

in-pct-2002-1092-che form-1.pdf

in-pct-2002-1092-che form-19.pdf

in-pct-2002-1092-che form-26.pdf

in-pct-2002-1092-che form-3.pdf

in-pct-2002-1092-che form-5.pdf

in-pct-2002-1092-che pct.pdf

in-pct-2002-1092-che petition.pdf