DE102021204937A1 - Method for optimizing a speed of an electric machine of an exhaust gas turbocharger, engine control unit and vehicle - Google Patents

Abstract

The present invention relates to a method for optimizing a speed (y(t)) of an electric machine (102-2) of an exhaust gas turbocharger (102), comprising: determining a reference variable (w(t)), the reference variable (w(t) ) corresponds to the setpoint speed of the electric machine (102-2); Determining an injection variable (u _v (t)) based on the command variable (w(t)), the determination of the injection variable (u _v (t)) comprising the following steps: detecting (230-1) a negative load change of a compressor (102 -3) the exhaust gas turbocharger (102); Determining (230-3) a maximum deceleration torque (M tot ) of the electrical machine ( _102-2 ) of the exhaust gas turbocharger (102). The invention also relates to an engine control unit (620) which is set up to carry out such a method, and a vehicle (100, 600) having such an engine control unit (620).

Description

The invention relates to a method for optimizing a speed of an electric machine of an exhaust gas turbocharger, an engine control unit for carrying out the optimization method and a vehicle which includes the engine control unit.

The consumption of internal combustion engines can be reduced enormously by consistently increasing the compression ratio. Here, for example, combustion processes according to Miller or combustion processes with low-pressure exhaust gas recirculation are used. These combustion processes require a high degree of supercharging in order to meet today's driving performance requirements.

In order to achieve this degree of supercharging, supercharging concepts such as electrically assisted exhaust gas turbochargers (euATL) can be used. These are driven by electrical energy and can generate additional boost pressure to the conventional exhaust gas turbocharger (ATL) or shift the operating point of the exhaust gas turbocharger. The torque generated by an euATL can be used both for braking and for accelerating the exhaust gas turbocharger. The boost pressure can be increased, but energy can also be recuperated. Nowadays they are mostly used to improve the response behavior of the internal combustion engine and thus the acceleration behavior of the vehicle. They can also be used, for example, for energy recuperation at nominal power. (e.g. high-performance concepts). Two strategies can be used for high-performance concepts: Energy recuperation, if exhaust gas temperature and exhaust back pressure allow it. The potential here is great because there is a lot of enthalpy in the exhaust gas. Short-term boosting is also possible in order to increase the nominal power. But here you need a lot of electrical power. EuATL are also used to lower the catalyst temperature.

If compressor surges of an exhaust gas turbocharger occur during a negative load change, undesirable noises (rattling noises, hissing and whistling during discharge) can occur due to pressure fluctuations.

Pumping can be prevented by using a diverter valve in the negative load change. Unwanted noises (chewing noises) can be reduced by constructive measures in air-conducting parts. A blow-off valve is an additional component that is associated with costs, additional functions for the procedure and the diagnosis, as well as with protection effort. In the event of a component failure, e.g. open clamping, a notifiable loss of performance results. The constructive noise suppression measures partially eliminate the symptom - the noise perception in the interior and near the vehicle is reduced, but not the cause.

DE 10 2018 121 017 A1 discloses a method for coordinated control of a boost system including a first compressor staged in a second compressor in an engine intake. A timing and amount of electrical assist provided to temporarily operate the first, upstream compressor may be dynamically adjusted as the pressure ratio at the second compressor changes. By matching a positive speed output to an electric motor that provides the electric assist, transient boost response may be enhanced. However, this method is not suitable for a targeted reduction of unwanted noises (chewing noises).

The object is therefore to provide an improved method for operating an internal combustion engine with an exhaust gas turbocharger and an electric machine as an euATL (electrically assisted exhaust gas turbocharger), in which the disadvantages specified above are at least partially eliminated and, in particular, noise is reduced in the event of a negative load change is possible.

This object is achieved by the method according to claim 1, the engine control unit according to claim 9 and the vehicle according to claim 10. Further advantageous refinements of the invention result from the dependent claims and the following description of preferred exemplary embodiments of the present invention.

• Ermitteln einer Führungsgröße, wobei die Führungsgröße der Soll-Drehzahl der elektrischen Maschine entspricht;
• Ermitteln einer Aufschaltungsgröße basierend auf der Führungsgröße, wobei das Ermitteln der Aufschaltungsgröße folgende Schritte umfasst:
  • Erkennen eines negativen Lastwechsels eines Verdichters des Abgasturboladers;
  • Ermitteln eines maximalen Verzögerungsmoments der elektrischen Maschine des Abgasturboladers.

A first aspect of the present invention relates to a method for optimizing a speed of an electric machine of an exhaust gas turbocharger, comprising:

• determining a reference variable, the reference variable corresponding to the target speed of the electrical machine;
• Determining an override variable based on the reference variable, the determination of the override variable comprising the following steps:
  • detecting a negative load change of a compressor of the exhaust gas turbocharger;
  • Determining a maximum deceleration torque of the electric machine of the exhaust gas turbocharger.

The purpose of the procedure is to regulate the speed in such a way that noises when the throttle is released (whistling and whistling of the throttle lever, rudder noises, etc.) are avoided. For this purpose, a torque is generated with the electric machine in order to brake the exhaust gas turbocharger and thus prevent/minimize noise during negative load changes. For example, the diverter valve can be dispensed with, or in the case of concepts without diverter valve, geometric measures in the intake scoop can be used.

The internal combustion engine can be an Otto engine. A gasoline engine is an internal combustion engine with spark ignition. An air-fuel mixture is burned and the chemical energy bound in the fuel is released and converted into mechanical energy. However, the concept can also be implemented in self-igniting engines, ie diesel engines.

In internal combustion engines with exhaust gas turbochargers, pressure fluctuations can occur due to compressor pumps in the event of negative load changes. These pressure fluctuations can be perceived by the customer as a chewing noise. The method enables the setting of a feedforward variable and direct and immediate work with a feedback signal from the controlled system. The speed of the electric machines can be adjusted on the basis of this feedforward variable in such a way that the unwanted noise is reduced.

The deceleration can take place through the generation of a negative moment (deceleration moment) by the electric machine in the exhaust gas turbocharger. The torque adjustment, with which the maximum deceleration is realized, can be realized with a pre-control. The maximum deceleration may be maintained until a speed differential threshold is exceeded. The adjustment to the target speed of the exhaust gas turbocharger by reducing the torque of the electric machine on the exhaust gas turbocharger can be carried out by a combination of the sine square pre-control and the conventional controller. With this combination, a largely jerk-free speed adjustment and a smooth torque curve can be guaranteed. In this way, compressor pumping can be effectively prevented. The acoustics of the exhaust gas turbocharger can be improved and energy recovery is also possible. In addition, the system can also be made more robust and the control speed can be increased.

• Ermitteln einer Stellgröße basierend auf der Führungsgröße;
• Erfassen einer Regelgröße;
• Ermitteln einer Sollwertabweichung basierend auf einer Abweichung der Führungsgröße und der Regelgröße;
• Ermitteln einer neuen Stellgröße anhand der Sollwertabweichung; und
• Korrigieren der neuen Stellgröße anhand der Aufschaltungsgröße umfassen.

In some embodiments, the method can:

• determining a manipulated variable based on the reference variable;
• detecting a controlled variable;
• determining a setpoint deviation based on a deviation of the reference variable and the controlled variable;
• Determining a new manipulated variable based on the setpoint deviation; and
• Correcting the new manipulated variable based on the injection variable.

By determining a new manipulated variable based on the setpoint deviation, disturbance variables can be further eliminated or reduced.

In some specific embodiments, the detection of the negative load changes of the compressor of the exhaust gas turbocharger
determining if the command is greater than a minimum speed;
determining a difference between the controlled variable and the reference variable of the exhaust gas turbocharger; and
Detecting a negative load change when the difference is greater than a predetermined value include.

The speed control of the electric machine of the exhaust gas turbocharger can be activated when two threshold values are exceeded. The first threshold value can be used to determine whether the difference between the actual and setpoint speeds of the exhaust gas turbocharger exceeds a defined value. On the other hand, a minimum speed may be required. If the speed control is activated, the maximum deceleration with which the exhaust gas turbocharger should be braked can first be calculated. This determination can be made with the help of a power balance, in which the maximum recuperation power, the maximum current, the heat development and other component limits of the electrical machine are taken into account. The speed difference can also be included.

In some specific embodiments, the maximum deceleration torque can be determined using a maximum recuperation power of the electrical machine. By taking into account the maximum recuperation power of the electric machine of the exhaust gas turbocharger to determine the maximum deceleration torque, the damage to the electric machine of the exhaust gas turbocharger can be reduced.

wobei U die Spannung der elektrischen Maschine, I_max der maximal zulässige Strom, η_E der elektrische Wirkungsgrad ist.In some embodiments, the maximum recuperation power P _E can be determined as follows: $$\text{recuperation performance}\left(P_E\right)=u\cdot I_{max}\cdot n_E.$$

where U is the voltage of the electrical machine, I _max is the maximum permissible current, η _E is the electrical efficiency.

With the desired eATL braking, power is generated by the e-machine as a generator. The resulting amperage depends on the efficiency of the electric motor on the exhaust gas turbocharger and also on the efficiency of the power electronics and the efficiency of storing the energy in the battery

In some specific embodiments, the maximum deceleration torque can be determined based on the performance of the exhaust gas turbocharger. By taking into account the power of the exhaust gas turbocharger to determine the maximum deceleration torque, damage to the electrical machine of the exhaust gas turbocharger can be reduced. The maximum power of the e-machine in generator mode can be stored as a boundary condition for the function (full load of the e-motor as a generator). It is a curve over the exhaust gas turbocharger speed, i.e. the performance during the deceleration process will change from the starting point down to a low speed (controlled operation). This is usually regulated by the power electronics.

In some specific embodiments, the maximum deceleration torque can be determined using a sine square pre-control. Compared to a controller with a similar curve, the sine square pre-control offers the advantage that it can be infinitely differentiated and has fewer parameters to be applied.

The exhaust gas turbocharger is an electrically assisted exhaust gas turbocharger (euATL). An electrically assisted exhaust gas turbocharger includes the electric machine. By integrating the electrical machine into the exhaust gas turbocharger, compressor surges can be suppressed and the existing kinetic energy can be used through recuperation. Furthermore, the dynamics of the system can be improved by the additional torque on the shaft of the exhaust gas turbocharger with the electric machine.

A second aspect relates to an engine control unit that is set up to carry out a method according to one of the preceding specific embodiments. The engine control unit can receive requests to the internal combustion engine, process them and send corresponding signals to actuators. Actuators can be electric motors or electromagnetic valves that are responsible for converting the signals from the control unit into a specific action.

A third aspect relates to a vehicle having the foregoing engine control device. The engine control unit can enable precise central control of the vehicle functions relevant to engine operation.

• 1 als ein Ausführungsbeispiel ein Fahrzeug mit einer Verbrennungskraftmaschine und einem elektrisch unterstützten Abgasturbolader;
• 2 als ein Ausführungsbeispiel, einen Drehzahlregelkreis für die elektrische Maschine (des Abgasturboladers);
• 3 als ein Ausführungsbeispiel, Verfahrensschritte der Vorsteuerung;
• 4 zeigt einen beispielhaften zeitlichen Verlauf des Ladedrucks und des Massenstroms, die sich aus dem Verdichter ergeben;
• 5 zeigt einen beispielhaften Verlauf des Drucksignals ohne die in 3 dargestellte Vorsteuerung und einen beispielhaften Verlauf des Drucksignals mit der in 3 dargestellten Vorsteuerung im Arbeitskennfeld des Verdichters; und
• 6 zeigt, als ein Ausführungsbeispiel, ein Fahrzeug mit einer Motoranordnung.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings. It shows:

• 1 as an exemplary embodiment, a vehicle with an internal combustion engine and an electrically assisted exhaust gas turbocharger;
• 2 as an embodiment, a speed control circuit for the electric machine (of the exhaust gas turbocharger);
• 3 as an embodiment, method steps of the pre-control;
• 4 shows an example of the course of the charge pressure and the mass flow over time, which result from the compressor;
• 5 shows an example of the pressure signal curve without the in 3 shown pre-control and an exemplary course of the pressure signal with the in 3 illustrated pilot control in the working map of the compressor; and
• 6 12 shows, as one embodiment, a vehicle having an engine assembly.

1 shows a vehicle with an internal combustion engine and an electrically assisted exhaust gas turbocharger (euATL) as an exemplary embodiment. The vehicle 100 includes an internal combustion engine 101, an electrically assisted exhaust gas turbocharger (euATL) 102, an intercooler 103, a throttle valve 104, an exhaust gas recirculation 105.

Internal combustion engine 101 can be a spark-ignition engine, in which case the spark-ignition engine can be used in partially electrified vehicles. The internal combustion engine 101 is driven by the combustion of a fuel-air mixture. The internal combustion engine 101 includes a piston, a cylinder, an intake valve, an exhaust valve, a fuel injector, and a spark plug. The energy conversion can take place either according to the four- or two-stroke principle.

The electrically assisted exhaust gas turbocharger (euATL) 102 includes a turbine 102-1 and a compressor 102-3. The turbine 102-1 uses the energy (thermal energy, ie heat energy, sometimes also kinetic energy, ie kinetic energy) of the exiting exhaust gases of the internal combustion engine 101 and is connected to the compressor 102-3. The compressor 102-3 is driven by the turbine 102-1, which increases the air throughput and reduces the suction work of the pistons. The electrically assisted exhaust gas turbocharger (euATL) 102 may further include a bypass valve (wastegate) in the exhaust flow to regulate boost pressure.

Furthermore, the turbine 102-1 may include variable turbine geometry (VTG) vanes. Due to the adjustable guide vanes, the inflowing gas can be given a higher angular momentum (in the form of a higher tangential velocity) at low flow velocities. The opening angle of the guide vanes can be regulated in such a way that when the gas throughput is low, the exhaust gas is accelerated tangentially by reducing the flow cross-sections - closing the VTG - and directed to the adjustable guide vanes, which increases the turbine output and thus the output of the compressor. Conversely, with a high gas throughput, the flow velocity can be reduced by large flow cross sections.

Furthermore, the electrically assisted exhaust gas turbocharger (euATL) 102 includes an electric machine 102-2. The electrically assisted exhaust gas turbocharger (euATL) 102 can additionally be accelerated or decelerated with controlled torque by the electric machine 102-2. In the case of stationary support, an additional torque can also be applied permanently. More efficient boundary conditions for the internal combustion engine can also be set. Braking for energy recuperation is also possible, with the operating point on the ATL (not on the engine) being shifted by a braking torque on the euATL shaft.

The electrical machine 102-2 can be arranged on the drive shaft 102-4 between the turbine 102-1 and the compressor 102-3 or also at a shaft end following the turbine 102-1 or the compressor 102-3. By means of the electrical energy supplied, additional charge pressure can be made available to increase the charge pressure and thus for acceleration. Braking is also possible in other operating modes. If compressor surges of an exhaust gas turbocharger occur during negative load changes, undesirable noises (rattling noises) can occur due to pressure fluctuations. To avoid this unwanted noise, in 2 a speed control loop of the electric machine 102-2 is shown. the inside 2 The speed control circuit shown can also increase the robustness of the exhaust gas turbocharger and improve the control speed.

The intercooler 103 serves as a heat exchanger that reduces the temperature of the combustion air fed into the intake tract of a supercharged internal combustion engine 101 . It can be installed in the intake tract between the compressor 102-3 and the intake valve of the internal combustion engine 101 and dissipates some of the heat that is produced when the air is compressed in the euATL 102. This increases the power and efficiency of the internal combustion engine 101. By lowering the temperature of the air supplied, a larger air mass is produced in the same volume, so that proportionately more fuel can be burned.

Throttle valve 104 is located in the intake tract of internal combustion engine 101. Together with euATL 102, throttle valve 104 regulates the air supply for internal combustion engine 101.

The exhaust gas of the internal combustion engine 101 is expanded via the turbine 102-1 of the euATL 102 and the compressor 102-3 of the euATL 102 is driven via the common shaft 102-4. The electric machine 102-2 is located on the shaft 102-4 of the euATL 102 and can electrically support the generation of the charging pressure. Recuperation via the electric machine 102-2 can also be useful at quasi-stationary operating points in some areas of the engine map to generate energy (e.g. to cover the on-board network requirement). After compression in the compressor 102-3 of the euATL 102, the fresh air is pumped through the intercooler 103 and the throttle valve 104 of the internal combustion engine 101 supplied.

The exhaust gas recirculation 105 may be low pressure exhaust gas recirculation (LP-EGR) and includes an exhaust gas recirculation valve 105-1 and an exhaust gas recirculation cooler 105-2. The low-pressure exhaust gas recirculation (LP-EGR) serves to reduce the tendency to knock in the knock-limited operating range of the internal combustion engine 101. This leads to better combustion center positions and thus to lower fuel consumption.

2 shows, as an embodiment, a speed control circuit for the electric machine (102-2 in 1 ) of the exhaust gas turbocharger (102 in 2 ).

The speed control circuit 200 includes a controller 210, a controlled system 220 and a pre-control 230. The pre-control 210 and the controller 210 detect a reference variable (setpoint) w(t), which corresponds to the setpoint speed of the electrical machine (102-2 in 1 ) of the exhaust gas turbocharger (102 in 2 ) is equivalent to.

The controller 210 determines a manipulated variable u _R (t) based on the recorded command variable w(t). This manipulated variable u _R (t) is forwarded to a controlled system 220 . The controlled system 220 uses the manipulated variable u _R (t) to determine a controlled variable (actual speed of the electrical machine) y(t), which corresponds to that of the electrical machine (102-2 in 1 ) of the exhaust gas turbocharger (102 in 2 ) is forwarded. The controlled variable y(t) can deviate from the command variable w(t) since the controlled system 220 can be influenced by various disturbance variables d(t). The controlled variable y(t) of the controlled system 220 is measured by a measuring element (not in 2 ) and is subtracted from the specified reference variable w(t). The controller 210 determines a new manipulated variable u _R (t) from the setpoint deviation (control deviation/control difference) and the specified control parameters. This acts on the controlled variable y(t) via the controlled system 220 in such a way that it minimizes the control deviation despite the presence of disturbance variables d(t) and the controlled variable y(t) assumes a desired time behavior depending on the selected quality criteria. The controller 210 can be a proportional controller (P controller), an integral controller (I controller), a proportional and integral controller (PI controller) or a proportional, integral and derivative controller (PID controller) or be a complex controller.

The pilot control 210 determines an injection variable u _v (t) based on the recorded reference variable w(t). This injection variable u _v (t) is combined (added) with the manipulated variable u _R (t) of the controller 210 . This would combine the desirable properties of robustness and interference compensation (chattering noises) of the control with fast reversal. In this case, the pilot control 210 could be selected in such a way that the controlled system 220 tracks the command variable w(t) as quickly as possible. A more detailed description of the procedural steps of pre-control 210 is in 3 shown.

The feed forward 210 may be a sine square feed forward. Compared to a PT5 controller, which has a similar curve, the sine square pre-control offers the advantage that it can be infinitely differentiated and has fewer parameters to be applied.

3 shows, as an exemplary embodiment, method steps of the pre-control (210 in 2 ).

The pre-control includes detection 230-1 of negative load changes of the compressor pumping of the exhaust gas turbocharger (102 in 2 ). Negative load changes of the compressor surge of the exhaust gas turbocharger (102 in 2 ) are detected when the difference between Actual (y(t) in 2 ) and target speed (w(t) in 2 ) of the exhaust gas turbocharger exceeds a defined value and a minimum speed is required.

wobei U die Spannung der elektrischen Maschine, I_max der maximal zulässige Strom, den das Bauteil (Leistungselektronik und/oder E-Maschine an der Turboladerwelle) aktuell leisten kann, η_E der elektrische Wirkungsgrad der ist.If a negative load change is detected, the maximum recuperation power of the electrical machine (102-2 in 1 ) of the exhaust gas turbocharger (102 in 1 ) determines 230-2. The maximum recuperation power P _E depends on the maximum permissible current I _max that the component (power electronics, the battery and/or electric machine on the turbocharger shaft) can currently deliver. The maximum recuperation power P _E can be determined as follows: $$P_E=u\cdot I_{max}\cdot n_E.$$

where U is the voltage of the electric machine, I _max is the maximum permissible current that the component (power electronics and/or electric machine on the turbocharger shaft) can currently deliver, η _E is the electric efficiency.

Based on the determined maximum recuperation power P _E , a maximum deceleration power P _tot is determined, from which a maximum deceleration torque M tot _230-3 can be derived, with which the exhaust gas turbocharger is braked. This determination can be made using a power balance, which takes into account the determined maximum recuperation power P _E , the maximum current, the heat development and other component limits of the electrical machine.

wobei P_turbo die Leistung des Abgasturboladers und P_E die maximale Rekuperationsleistung ist. Die Leistung P_turbo des Abgasturboladers kann anhand der Turbinendrehzahl n und des Wirkungsgrads η_turbo des Abgasturboladers mithilfe des Druck- und Massenstromverhältnisses ermittelt werden.The maximum deceleration power P _tot can be determined as follows: $$P_{Ges}=P_{t\mathrm{and}\mathrm{right}bO}+P_E$$

where P _turbo is the output of the exhaust gas turbocharger and P _E is the maximum recuperation output. The output P _turbo of the exhaust gas turbocharger can be determined using the turbine speed n and the efficiency η _turbo of the exhaust gas turbocharger using the pressure and mass flow ratio.

wobei η_turbo der Wirkungsgrad des Abgasturboladers, h eine Größe für das Druck- und Massenstromverhältnis und n die Drehzahl ist.The output P _turbo of the exhaust gas turbocharger can be determined as follows: $$P_{t\mathrm{and}\mathrm{right}bO}=n\cdot n_{t\mathrm{and}\mathrm{right}bO}\cdot H$$

where η _turbo is the efficiency of the exhaust gas turbocharger, h is a variable for the pressure and mass flow ratio and n is the speed.

Based on the maximum deceleration torque 230-3 determined in this way, an injection variable (u _v (t) in 2 ) determines 230-4 which to the manipulated variable (u _R (t) in 2 ) of the regulator (210 in 2 ) is combined (added). The deceleration moment takes place by a negative moment by the elec ric machine is generated. The torque adjustment, with which the maximum deceleration is realized, is realized with the pre-control. The electric machine is then braked using the maximum deceleration torque until a threshold value of the speed difference is exceeded. The adjustment to the target speed of the exhaust gas turbocharger by reducing the torque of the electric machine results from a combination of the sine square pre-control and the conventional controller.

4 shows an example of the course of the charge pressure and the mass flow over time, which result from the compressor (102-3 in 1 ) result.

The x-axis of 4 represents the time axis in seconds, the Y1 axis from 4 represents the pressure axis in hectopascals and the Y2 axis of 4 represents the mass flow axis in kg/h (kilograms per hour). Line L1 corresponds to the mass flow resulting from the compressor (102-3 in 1 ) and line L2 corresponds to boost pressure resulting from the compressor (102-3 in 1 ). Area E is the area in which a negative load change occurs. In area E, a high-frequency oscillation of the compressor pumps occurs, which results in the actual speed (actual speed of the electric machine) of the electric machine.

5 shows an example of the pressure signal curve without the in 3 shown pre-control and an exemplary course of the pressure signal with the in 3 shown pre-control in the working map of the compressor (102-3 in 1 ).

The x-axis of 5 represents the mass flow axis (air mass flow) in kg/h (kilograms per hour) and the y-axis of 5 represents the pressure ratio. The working range in the operating map of the compressor (102-3 in 1 ) is limited on the one hand by the surge limit P, on the other hand by the choke limit S and the maximum permissible speed (physical turbocharger speed) n of the compressor. The surge limit P separates the areas of stable P1 and unstable P2 flow conditions in the operating map. The behavior of the compressor is referred to as unstable P1 when there is a cyclic backflow of the intake air. The choke limit S is the maximum possible volume flow or mass flow that exits the compressor when the pressure drops. At sufficiently high speeds, the speed of sound is reached in the narrowest cross-section of the compressor. This critical flow area can be located either in the flow channel of the impeller or in the diffuser.

The line L500 corresponds to the pressure signal without the in 3 shown pilot control. As in 5 As can be seen, the pressure signal of line L500 enters the unstable area P1 when the mass flow is below 150 kg/h. The line L510 corresponds to the pressure signal with the in 3 shown pilot control. Due to the balanced recuperation of the electric motor (electrical machine 102-2 in 1 ) of the exhaust gas turbocharger (102 in 1 ) the pressure signal does not enter the unstable range P1, even if negative load changes occur.

6 12 shows, as one embodiment, a vehicle 600 having an engine assembly. The engine assembly 610 includes an engine controller 620 and an internal combustion engine (101 in 1 or 4 ). Engine control unit 620 is designed to control the speed control circuit for the electric machine (102-2 in 1 ) of the exhaust gas turbocharger (102 in 2 ). after 2 to perform.

Reference List

100; 600

vehicle

101

internal combustion engine

102

electrically assisted exhaust gas turbocharger (euATL)

102-1

turbine

102-2

electric machine

102-3

compressor

102-4

Wave

103

intercooler

104

throttle

105

exhaust gas recirculation

200

speed control loop

210

controller

220

controlled system

230

pre-control

w(t)

benchmark

uR(t)

manipulated variable

y(t)

controlled variable

uv(t)

staging size

PE

maximum recuperation performance

Pges

maximum deceleration performance

mg

maximum deceleration torque

Pturbo

Performance of the exhaust gas turbocharger

η turbo

Efficiency of the exhaust gas turbocharger

ηE

Efficiency of the electric machine

H

Quantity for the pressure and mass flow ratio

n

speed of the turbine

u

Voltage of the electrical machine

Imax

maximum allowable current

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018121017 A1 [0006]

Claims (10)

A method for optimizing a speed (y(t)) of an electric machine (102-2) of an exhaust gas turbocharger (102), comprising: determining a command variable (w(t)), the command variable (w(t)) being the target speed corresponds to the electric machine (102-2); Determining an injection variable (u _v (t)) based on the command variable (w(t)), the determination of the injection variable (u _v (t)) comprising the following steps: detecting (230-1) a negative load change of a compressor (102 -3) the exhaust gas turbocharger (102); Determining (230-3) a maximum deceleration torque (M tot ) of the electrical machine ( _102-2 ) of the exhaust gas turbocharger (102). procedure after claim 1 , further comprising: determining a manipulated variable (u _R (t) based on the command variable (w(t)); detecting a controlled variable (y(t)); determining a setpoint deviation (w(t)−y(t)) based on a deviation of the reference variable (w(t)) and the controlled variable (y(t)); determining a new manipulated variable (u _R (t) based on the setpoint deviation (w(t) - y(t)); and correcting the new manipulated variable (u _R (t) based on the feed-in variable (u _v (t)). Method according to one of the preceding claims, wherein the detection (230-1) of the negative load changes of the compressor (102-3) of the exhaust gas turbocharger (102) comprises: determining whether the command variable (w(t)) is greater than a minimum speed; determining a difference between the controlled variable (y(t)) and the reference variable (w(t)) of the exhaust gas turbocharger (102); and Recognizing a negative load change when the difference is greater than a predetermined value. Method according to one of the preceding claims, wherein the maximum deceleration torque (M tot ) is determined on the basis of a maximum recuperation power (P _E ) of the electrical machine ( _102-2 ). Method according to one of the preceding claims, wherein the maximum recuperation power (P _E ) is determined as follows: $$\text{recuperation performance}\left(P_E\right)=u\cdot I_{max}\cdot n_E,$$

where U is the voltage of the electrical machine, I _max is the maximum permissible current, η _E is the electrical efficiency. Method according to one of the preceding claims, in which the maximum deceleration torque (P _tot ) is determined on the basis of the output of the exhaust gas turbocharger (102). Method according to one of the preceding claims, wherein the maximum deceleration torque (P _tot ) is determined using a sine square pre-control. Method according to one of the preceding claims, wherein the exhaust gas turbocharger (102) is an electrically assisted exhaust gas turbocharger. Engine control unit (620), which is set up to use a method according to one of Claims 1 until 8th to perform. Vehicle (100; 600) with an engine control unit (10). claim 9 .

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