DE102017000764B4 - 1 method for operating a drive device and corresponding drive device - Google Patents

Abstract

Method for operating a drive device with at least one internal combustion engine, wherein from a predetermined default torque determines a target torque and an actual torque supplied by the internal combustion engine is set to the target torque, wherein the internal combustion engine is torque-oriented controlled and / or regulated, characterized in that • at constant setpoint torque the actual torque of the internal combustion engine is read from a steady-state torque map using the Istkraftstoffmassenstroms as an input variable and transient default torque, the actual torque is determined from a first partial torque and a second partial torque, wherein the first partial torque read out of the steady-state torque map using the Istkraftstoffmassenstroms as input and the second partial torque corresponds to a differential torque, and / or • at a constant preset value hmoment the setpoint torque is set equal to the default torque and is determined at transient setpoint torque of the first partial torque and the second partial torque, the first partial torque of the default torque and the second partial torque corresponds to the differential torque, wherein in determining the desired torque and / or the actual torque Taking into account transient effects used differential torque from a first parameter and a second parameter is determined, the first parameter from a statically fed Kennzahlenkennfeld using at least one operating variable of the internal combustion engine read as an input and the second parameter is measured and / or modeled.

Description

The invention relates to a method for operating a drive device having at least one internal combustion engine, wherein a setpoint torque is determined from a given default torque and an actual torque provided by the internal combustion engine is set to the desired torque, wherein the internal combustion engine is controlled and / or regulated in a torque-oriented manner. The invention further relates to a drive device.

The drive device serves, for example, for driving a motor vehicle, insofar as it provides the provision of a torque directed to driving the motor vehicle. The drive device has the internal combustion engine, which is controlled torque-oriented and / or regulated. This means that the internal combustion engine is operated on the basis of torques, namely the actual torque and the setpoint torque. The internal combustion engine is adjusted during its operation such that the actual torque is adjusted in the direction of the desired torque or set exactly to this.

To set the actual torque of the internal combustion engine is supplied to a certain amount of fuel or a certain fuel mass flow. In the case of the control of the internal combustion engine is so far from the actual torque - corresponding to a controlled variable - and the setpoint torque - determined according to a reference variable - a control difference, whereas the amount of fuel or the fuel mass flow serves as a control variable. The control difference corresponds for example to a difference between the actual torque and the target torque, wherein the control is directed to minimizing the control difference. Finally, it is therefore envisaged to set the desired torque on the internal combustion engine and to adjust the actual torque provided by the internal combustion engine to it in a controlling and / or regulating manner. The setpoint torque is determined based on the default torque, wherein the default torque is predetermined, for example, by a driver of the motor vehicle and / or a driver assistance device. The default torque corresponds so far in particular a driver's request.

From the prior art, for example, the publication DE 10 2007 053 719 B3 known. This describes a method for operating a direct injection internal combustion engine, wherein at least one cylinder characteristic variable determining the quantity of gases contained in the cylinder and at least one relevant cylinder characteristic for the quality of the gases contained in the cylinder are determined prior to an injection of fuel into a cylinder of the internal combustion engine , and are set in the control quantities for an injection strategy taking into account the cylinder characteristics. It is provided that is determined as the cylinder characteristic quantity for the mass of the gases contained in the inlet closing in the cylinder and that as a cylinder characteristic for the quality, the oxygen concentration of the gases contained in the cylinder, the mass fraction of the inert gases and / or the temperature of the cylinder filling respectively at the inlet is / are determined.

Furthermore, the document describes DE 10 2016 103 417 A1 a control device for an internal combustion engine with an ECU. The ECU is configured to: calculate a normalized inlet pressure; calculate a pumping loss torque based on the normalized inlet pressure; calculate a first value or a value of a linear function as the normalized inlet pressure, wherein the first value is obtained by dividing the inlet pressure by the atmospheric pressure; calculate the output value based on the normalized inlet pressure and compare data associating a normalized output value with the normalized inlet pressure; wherein the output value is one of a second value obtained by dividing the pumping loss torque by the atmospheric pressure, a normalized pumping loss torque, a third value obtained by dividing an exhaust gas pressure by the atmospheric pressure, and a normalized exhaust gas pressure; and calculate one of the pumping loss torque and the exhaust pressure.

Furthermore, the document describes DE 28 03 750 A1 a method and a device for fuel metering in internal combustion engines.

It is an object of the invention to propose a method for operating a drive device, which has advantages over known methods, in particular allows a faster and / or more accurate setting of the actual torque to the target torque, in particular during a transient operating state of the drive device or the internal combustion engine.

This is achieved according to the invention by a method having the features of claim 1. It is envisaged that at a constant default torque, the actual torque of the internal combustion engine is read out of a stationary gedateten torque map using the actual fuel mass flow as an input variable and transient default torque, the actual torque of a first partial torque and a second partial torque is determined, wherein the first partial torque is read out of the stationary-fed torque map using the actual fuel mass flow as an input variable and the second partial torque corresponds to a differential torque; and / or at constant default torque the target torque is set equal to the default torque and is determined at transient default torque from the first part torque and the second part torque, the first part torque corresponding to the default torque and the second part torque to the differential torque; wherein the differential torque used in determining the target torque and / or the actual torque to account for transient effects of a first characteristic and a second characteristic is determined, wherein the first characteristic from a statically fed characteristic map using at least one operating variable of the internal combustion engine read as input and the measured second parameter and / or modeled.

It has already been explained above that the actual torque and the setpoint torque are used to control and / or regulate the internal combustion engine. One of these two variables, ie either the actual torque or the desired torque, or both variables are determined taking into account the differential torque. The respective size or the two sizes are so far in each case as a function of the differential torque. The differential torque is composed of several parameters, namely the first parameter and the second parameter.

The first parameter is read from the characteristic map, wherein the at least one operating variable of the internal combustion engine is used as an input variable. The first parameter is so far as the output of the characteristic map before. The characteristic map is stationary. This means that the relationships stored in it are static and are not changed during operation of the drive device. Particularly preferably, the characteristic map is only readable in operation, that is not writable or rewritable. The first parameter serves as a reference parameter. Accordingly, the characteristics map can also be referred to as a reference map.

The relationship contained in the characteristics map between the at least one operating variable of the internal combustion engine and the first parameter is preferably determined on a test bench based on a further internal combustion engine, which may be referred to as a reference internal combustion engine. The relationships contained in the characteristics map are so far uniform for an internal combustion engine family and find correspondingly for a variety of identical or at least construction-like internal combustion engine application, the physically identical or at least behave similar. However, the use of the same internal combustion engine for determining the characteristics map can also be provided.

In addition to the first parameter, the second parameter is included in the differential torque, so that the first parameter serving as a reference parameter is superimposed with the second parameter to take account of dynamic operation of the internal combustion engine. The second parameter is measured and / or modeled. This means that at least one sensor and / or at least one model is used to determine the parameter. Of course, the parameter may also be present as the output variable of the model, wherein a measured value measured serves as input for the model. It may also be provided to determine the parameter on the basis of both a measured measured value and a modeled model value, for example by averaging.

The difference torque is summarized as a function of both the first parameter and the second parameter, so these represent input variables of a corresponding function. Particularly preferably, the differential torque is determined exclusively from the first parameter and the second parameter. The use of the differential torque in determining the desired torque and / or the actual torque allows the consideration of transient effects, which may occur in particular when changing the default torque. The difference torque can basically be both positive and negative. In the case of the positive differential torque, the transient effects cause a loss. Alternatively, therefore, the differential torque may also be referred to as lost torque.

A further embodiment of the invention provides that an actual fresh gas mass flow of the fresh gas supplied to the internal combustion engine, an actual fuel mass flow of the fuel supplied to the internal combustion engine, a mixing ratio of actual fresh gas mass flow and actual fuel mass flow, and / or an actual internal combustion engine speed is used as the operating variable. In this case, exactly one of these variables can be used as the operating variable or as the input variable for the characteristics map. Preferably, however, several, so at least two of mentioned sizes, used as input variables, particularly preferably all of the mentioned sizes.

The actual fresh gas mass flow describes the amount of fresh gas supplied to the internal combustion engine per unit time, fresh gas preferably being understood to mean fresh air or an exhaust-fresh air mixture. The actual fuel mass flow in turn describes the amount of fuel supplied to the internal combustion engine per unit time, wherein preferably the same time unit is used for the determination of the actual fresh gas mass flow and the actual fuel mass flow. The mixing ratio corresponds to the ratio between actual fresh gas mass flow and actual fuel mass flow or vice versa. Under the Istbrennkraftmaschinendrehzahl the instantaneous speed of the internal combustion engine is to be understood.

The invention provides that at constant setpoint torque, the actual torque of the internal combustion engine is read from a steady-state torque map using the Istkraftstoffmassenstroms as an input variable and that at transient setpoint torque the actual torque of a first partial torque and a second partial torque is determined, the first partial torque of the stationary gedateten torque map is read using the actual fuel mass flow as input and the second partial torque corresponds to the differential torque, which can be positive or negative.

The constant preset torque is to be understood as meaning a constant preset torque over time, which therefore has a gradient over time of zero, in particular over an infinitesimally small period of time. The transient default torque, however, changes over time, so has a gradient which is different from zero. It is particularly advantageous to use the procedure described in the case of a power increase of the internal combustion engine, so that the transient specification torque is understood in particular to be a predefined torque having a gradient of greater than zero, that is to say an increasing default torque.

If the default torque is constant, the actual torque is read from the torque map. This is as well as the characteristics map stationary bedatet, so that the corresponding explanations for the characteristic map also apply to the torque map. The torque map relates the actual torque with the actual fuel mass flow in relation, thus contains a corresponding relationship between the actual torque and the actual fuel mass flow The actual torque is available as an output variable of the torque map.

If, on the other hand, the preset torque is transient, then the actual rotational torque is composed of the first partial torque and the second partial torque. The first partial torque corresponds to the actual torque at a constant preset torque, that is to say it is read from the stationary torque map using the actual fuel mass flow as the input variable. As a second partial torque, however, the difference torque already described above is used. With a transient setpoint torque, the actual torque is a function of the first partial torque and the second partial torque and thus as a function of the first partial torque, the first characteristic and the second characteristic.

It should be noted that a constant default torque rarely occurs in practice. In particular, it can be realized on the test bench. It can therefore also be provided that the actual torque is always determined from the first partial torque and the second partial torque.

A further development of the invention provides that a desired fuel mass flow to be supplied to the internal combustion engine is read out from a stationary fuel quantity map using the desired torque as an input variable. The fuel quantity map sets the desired fuel mass flow in relation to the target torque, thus contains a corresponding relationship. The fuel quantity map is stationary bedatet. Again, attention is drawn to the corresponding explanations for the characteristics map, which can be used analogously. The desired fuel mass flow corresponds to the amount of fuel which is to be supplied to the internal combustion engine per unit time. For example, the fuel quantity map and the torque field are based on the same model or are one and the same characteristic map, which is inverted or inverted in one case.

The desired fuel mass flow is set on the internal combustion engine, which adapts the actual fuel mass flow actually introduced into the internal combustion engine accordingly, in particular in such a way that it corresponds to the desired fuel mass flow. Ideally, therefore, the actual fuel mass flow coincides with the desired fuel mass flow. However, deviations between the desired fuel mass flow and the actual fuel mass flow may occur, in particular with a transient setpoint torque. The desired fuel mass flow is the output of the Fuel quantity map and insofar as a function of the target torque before.

According to the invention, it is provided that the setpoint torque is set equal to the default torque at a constant default torque, and that the target torque is determined from the first partial torque and the second partial torque at transient preset torque, wherein the first partial torque corresponds to the default torque and the second partial torque corresponds to the differential torque. First, reference is made to the above statements with regard to the constant and the transient default torque. Again, it may be provided to always determine the target torque from the first partial torque and the second partial torque, because a constant default torque rarely occurs in practice.

At constant setpoint torque, the setpoint torque should now correspond to the default torque. If, on the other hand, the preset torque is transient, the setpoint torque is composed of a plurality of partial torques, namely the first partial torque and the second partial torque. The first partial torque corresponds to the default torque and the second partial torque corresponds to the differential torque. In other words, the desired torque is a function of the first partial torque and the second partial torque and correspondingly as a function of the first partial torque, the first characteristic and the second characteristic.

A further preferred embodiment of the invention provides that the actual torque results from subtracting the second partial torque from the first partial torque, and / or that the setpoint torque results from an addition of the first partial torque and the second partial torque. The difference torque describes a reduction of the torque provided by the internal combustion engine due to transient processes. Accordingly, the actual torque decreases based on the first partial torque read from the torque map. Conversely, a larger target torque must be set to the internal combustion engine, so that the actual torque generated by the internal combustion engine corresponds to the default torque. Consequently, the setpoint torque is increased by the second partial torque based on the first partial torque.

A further embodiment of the invention provides that in each case an exhaust backpressure is used as the first parameter and as the second parameter. The exhaust back pressure describes the pressure of the exhaust gas generated by the internal combustion engine downstream of the internal combustion engine, for example, immediately downstream of the internal combustion engine. The exhaust gas generated by the internal combustion engine is discharged via an exhaust manifold into an exhaust pipe, after its passage through it, for example, in an external environment of the drive device is applied.

The exhaust backpressure can now be, for example, the pressure of the exhaust gas in the exhaust manifold or in the exhaust pipe. For example, the exhaust gas backpressure upstream of an exhaust gas purification device, such as a catalyst and / or a particulate filter or the like, is determined. However, the exhaust backpressure can also be determined upstream of an exhaust gas turbocharger of the drive device which is assigned to the internal combustion engine.

A further embodiment of the invention provides that the internal combustion engine is subjected to fresh gas by means of at least one exhaust gas turbocharger, in particular by means of an exhaust gas turbocharger having a variable turbine cross section. The exhaust gas turbocharger is used for compressing the fresh gas supplied to the internal combustion engine. By means of the exhaust gas turbocharger or a compressor of the exhaust gas turbocharger fresh gas is received in this respect at a first pressure and compressed to a higher second pressure. The first pressure corresponds for example to an ambient pressure of the drive device. After its compression, the fresh gas is supplied to the internal combustion engine.

In addition to the compressor, the exhaust gas turbocharger has a turbine, namely via an exhaust gas turbine. The exhaust gas turbine is at least partially, in particular completely, supplied to the exhaust gas generated by the internal combustion engine. When passing through the exhaust gas turbine enthalpy or flow energy is removed from the exhaust gas and converted into kinetic energy, which is subsequently used to operate the compressor. The exhaust gas turbine of the exhaust gas turbocharger can have the variable turbine cross section, that is to say for example have a stator with adjustable guide vanes.

Finally, it can be provided within the scope of a further preferred embodiment of the invention that the second characteristic of a turbine mass flow, an exhaust gas temperature, a turbine cross section of the engine associated exhaust gas turbocharger, a heat capacity, the actual fuel mass flow, the Istfrischgasmassenstrom, the Istbrennkraftmaschinendrehzahl or a fresh gas fuel mass ratio is determined. It has already been mentioned above that the second characteristic can basically be measured or modeled. In the case of modeling, different values can be used as a function of the second parameter. These values are, for example, the turbine mass flow, that is to say the exhaust gas mass flow supplied to a turbine of the exhaust gas turbocharger, the exhaust gas temperature or the turbine cross section.

The turbine cross-section is to be understood as meaning the flow cross-section of the exhaust-gas turbocharger, in particular the smallest flow-through cross section across the exhaust-gas turbocharger or its turbine. Furthermore, of course, the heat capacity can be taken into account, in particular the exhaust gas and / or the drive device or a part thereof. The fresh gas / fuel mass ratio can also be included in the modeled second parameter. This is to be understood as the ratio between the actual fresh gas mass flow and the actual fuel mass flow or alternatively between the desired fresh gas mass flow and the desired fuel mass flow. At least one, but preferably several or all of the mentioned variables can be used in the determination of the second parameter.

The invention further relates to a drive device with the features of claim 8.

The advantages of such an approach or such an embodiment of the drive device has already been discussed. Both the drive device and the method for operating it can be developed further in accordance with the above explanations, so that reference is made to this extent.

• 1 eine schematische Darstellung von Funktionsblöcken zur Bestimmung eines Istdrehmoments einer Brennkraftmaschine einer Antriebseinrichtung aus mehreren Teildrehmomenten, sowie
• 2 einen Funktionsblock zur Ermittlung einer Kenngröße, welche bei der Bestimmung eines Differenzdrehmoments herangezogen wird.

The invention will be explained in more detail with reference to the embodiments illustrated in the drawings, without any limitation of the invention. Showing:

• 1 a schematic representation of functional blocks for determining an actual torque of an internal combustion engine of a drive device of several partial torques, and
• 2 a function block for determining a parameter, which is used in the determination of a differential torque.

The 1 shows a function block 1 which is used in a method for operating a drive device for a motor vehicle application. The drive device has at least one internal combustion engine. The function block 1 has as input an actual fresh gas mass flow m _air , an actual fuel mass flow m _fuel and an actual engine speed n. The output block is provided by the function block 1 a first partial torque M _stat , which represents a proportion of the actual torque, which is present at a constant preset torque. The default torque is a predetermined by a driver of the motor vehicle and / or a driver assistance device torque from which subsequently a target torque is determined, to which the internal combustion engine is adjusted.

Furthermore, a functional block 2 to recognize which as input variables a first parameter p _3stat , a second parameter p ₃ and an engine dependent constant k. The first parameter p _3stat is preferably read from a statically fed Kennzahlenkennfeld using at least one operating variable of the internal combustion engine. In turn, the operating mass can be the actual fresh gas mass flow mair, the actual fuel mass flow m _fuel and the actual engine speed n are used. The second parameter p ₃ however, is preferably measured or modeled.

The output block is the function block 2 a difference torque ΔM _trans on, which is used as a second partial torque. In a functional block 3 Now the first partial torque Mstat and the second partial torque ΔM _trans merged, with a transient actual torque M _trans by subtracting the second partial torque ΔM _trans from the first partial torque M _stat results. This transient actual torque can subsequently be used for a torque-oriented control and / or regulation of the internal combustion engine.

The 2 shows a schematic representation of a functional block 4 , which is the model-based determination of the second parameter p ₃ serves. As input variables of the function block 4 find a turbine cross section A _teff one of the internal combustion engine associated exhaust gas turbocharger, a turbine mass flow m _T and an exhaust gas temperature T ₃ Use. Furthermore, the general gas constant R and an isentropic exponent κ as input variables of the function block 4 serve, which describe the expansion process of the exhaust gas in an exhaust gas turbine of the exhaust gas turbocharger. The isentropic exponent κ can be a constant. However, it is particularly preferably determined as a function of at least one size, in particular a temperature. This determination can be made using a mathematical relationship, a map and / or a table. The temperature used is in particular the temperature of the exhaust gas.

By means of the described procedure, transient phenomena which occur during operation of the drive device or of the internal combustion engine can be taken into account for the control and / or regulation of the internal combustion engine. These phenomena have a significant influence on the torque release of the internal combustion engine, especially if it has the exhaust gas turbocharger. With the aid of the procedure described so far, the control and / or regulation of the internal combustion engine can be significantly improved with regard to its quality and / or its positioning speed.

Claims (8)

Method for operating a drive device with at least one internal combustion engine, wherein from a predetermined default torque determines a target torque and an actual torque supplied by the internal combustion engine is set to the target torque, wherein the engine is torque-controlled and / or regulated, characterized in that • at constant default torque the actual torque of the internal combustion engine is read from a steady-state torque map using the Istkraftstoffmassenstroms as an input variable and transient default torque, the actual torque is determined from a first partial torque and a second partial torque, wherein the first partial torque read out of the steady-state torque map using the Istkraftstoffmassenstroms as input is and the second partial torque corresponds to a differential torque, and / or • at constant specification torque, the target torque is set equal to the default torque and is determined at transient default torque of the first partial torque and the second partial torque, wherein the first partial torque of the default torque and the second partial torque corresponds to the differential torque, wherein in determining the desired torque and / or the actual torque Taking into account transient effects used differential torque from a first parameter and a second parameter is determined, the first parameter from a statically fed Kennzahlenkennfeld using at least one operating variable of the internal combustion engine read as an input and the second parameter is measured and / or modeled. Method according to Claim 1 characterized in that the operating variable used is an actual fresh gas mass flow of the fresh gas supplied to the internal combustion engine, an actual fuel mass flow of the fuel supplied to the internal combustion engine, a mixing ratio of actual fresh gas mass flow and actual fuel mass flow, and / or an actual internal combustion engine speed. Method according to one of the preceding claims, characterized in that a target fuel mass flow to be supplied to the internal combustion engine is read out using the setpoint torque as an input variable from a stationary fuel quantity map. Method according to one of the preceding claims, characterized in that the actual torque results by subtracting the second partial torque of the first partial torque, and / or that the target torque results from an addition of the first partial torque and the second partial torque. Method according to one of the preceding claims, characterized in that in each case an exhaust backpressure is used as the first parameter and as the second parameter. Method according to one of the preceding claims, characterized in that the internal combustion engine is acted upon by means of at least one exhaust gas turbocharger with fresh gas, in particular by means of a variable turbine cross-section having exhaust gas turbocharger. Method according to one of the preceding claims, characterized in that the second parameter from a turbine mass flow, an exhaust gas temperature, the turbine cross section of the internal combustion engine associated exhaust gas turbocharger, a heat capacity, the actual fuel mass flow, the Istfrischgasmassenstrom, the Istbrennkraftmaschinendrehzahl and / or a fresh gas fuel mass ratio determined becomes. Drive device for carrying out the method according to one or more of the preceding claims, with at least one internal combustion engine, wherein the drive device is adapted to determine a target torque from a predetermined default torque and set an actual torque provided by the internal combustion engine to the target torque, the engine controlled torque-oriented and / or is regulated, characterized in that • at constant setpoint torque, the actual torque of the internal combustion engine is read out of a steady-state torque map using the Istkraftstoffmassenstroms as input and at transient default torque, the actual torque is determined from a first partial torque and a second partial torque, the first partial torque off the steady-state torque map is read using the actual fuel mass flow as an input and the second partial torque equals a differential torque; and / or at constant default torque the target torque is set equal to the default torque and is determined from the first partial torque and the second partial torque at transient setpoint torque the first partial torque corresponds to the default torque and the second partial torque corresponds to the differential torque, wherein the drive device is further configured to determine the differential torque used in determining the desired torque and / or torque to account for transient effects from a first characteristic and a second characteristic the first parameter is read out from a statically fed parameter map using at least one operating variable of the internal combustion engine as an input variable and d The second part parameter is measured and / or modeled.

Images