Procedures for operating a motor vehicle

Abstract

A method for operating a power machine arrangement, wherein the power machine arrangement comprises the following: a power machine; a turbocharger arrangement and a control parameter of the turbocharger arrangement that is controllable to control a level of gain provided by the turbocharger arrangement, the method comprising: Determining a desirable pressure limit of exhaust gases upstream of the turbine of the turbocharger assembly; Predicting a desirable limit value of the control parameter to be applied to the turbocharger arrangement in order to achieve the desired pressure limit; Determining an error within the desired limit of the control parameter; Setting the desired limit value of the control parameter based on the error; and Controlling the operation of the turbocharger assembly so that the adjusted limit value is not exceeded, characterized in that Determining the error within the desired limit of the control parameter includes the following: Predicting a current value of the control parameter based on a current pressure of exhaust gases upstream of the turbine; Determining a current value of the control parameter; and Determining the error between the predicted current value of the control parameter and the actual value of the control parameter.

Description

Technical field

[0001] The present disclosure relates to a method and system for operating a power machine arrangement and deals in particular, but not exclusively, with a method for operating a power machine arrangement in order to improve the reliability of the power machine arrangement. background

[0002] Turbochargers for power engine assemblies, such as those in motor vehicles, typically include a mechanism for adjusting the level of boost provided by the turbocharger. For example, the turbocharger may include a variable geometry turbine (VGT), which comprises a set of adjustable vanes for controlling the flow of gases through the turbine to regulate the energy supplied to a compressor within the turbocharger to compress intake gases. Alternatively, the turbocharger may include a bypass channel designed to allow a controllable proportion of the exhaust gases to bypass the turbine.

[0003] Turbocharged turbines are generally designed to operate up to a maximum inlet pressure and / or a maximum pressure ratio between the turbine inlet and outlet. Above the maximum inlet pressure or pressure ratio, the turbine's performance may be reduced. Furthermore, if the inlet pressure regularly exceeds the turbine's maximum design inlet pressure, or increases to such an extent that the turbine's maximum pressure ratio is exceeded, the turbocharger may be damaged or require more intensive and / or frequent maintenance.

[0004] When the turbocharger is controlled to adjust the level of boost provided, the exhaust gas pressure upstream of the turbine, for example within an exhaust manifold of the engine assembly, can change and approach the maximum design pressure. For instance, if the angle of the variable turbine geometry (VTG) vanes is adjusted and an inlet area of ​​the VTG is reduced, the exhaust gas pressure upstream of the VTG can increase.

[0005] Some power unit assemblies include a pressure sensor designed to measure the exhaust gas pressure within the exhaust manifold. The measurement obtained from the pressure sensor can be used to control the operation of the turbocharger, for example, within a closed feedback loop.

[0006] The exhaust manifold pressure sensor enables precise control of the turbocharger assembly in response to changes in exhaust manifold pressure. However, using real-time pressure measurements to determine how the turbocharger should be controlled can lead to an undesirably long reaction time between an increase in exhaust manifold pressure and the response of the turbocharger or another vehicle system. Furthermore, because the turbocharger is controlled based on a real-time measurement of the exhaust manifold pressure, in some configurations the turbocharger is only controlled to reduce the exhaust manifold pressure below the maximum design pressure as soon as a high pressure is detected.

[0007] Document DE 10 2013 113 645 A1 discloses a method and a device for operating an internal combustion engine using an intake air compressor.

[0008] Document US 2017 / 0335780A1 discloses a method and a system for operating an engine.

[0009] An improved method for controlling the operation of a turbocharger assembly with the aim of preventing the exhaust manifold pressure from exceeding the maximum design pressure is desirable. Brief description of the invention

[0010] According to one aspect of the present disclosure, a method for operating a power machine arrangement is provided, wherein the power machine arrangement comprises the following: a power machine; a turbocharger arrangement and a control parameter of the turbocharger arrangement that is controllable to control a level of gain provided by the turbocharger arrangement, the method comprising: Determining a desirable pressure limit of exhaust gases upstream of a turbine in the turbocharger assembly, e.g. in an exhaust manifold or a high-pressure exhaust channel; Predicting a desirable limit value of the control parameter to be applied to the turbocharger arrangement in order to achieve the desired pressure limit; Determining an error within the desired limit of the control parameter; Setting the desired limit value of the control parameter based on the error; and Controlling the operation of the turbocharger assembly so that the adjusted limit value is not exceeded.

[0011] Determining the error within the desired limit of the control parameter includes the following: Predicting a current value of the control parameter based on a current pressure of exhaust gases upstream of the turbine; Determining a current, e.g., measured, value of the control parameter; and Determining the error between the predicted current value of the control parameter and the actual value of the control parameter.

[0012] Determining the current value of the control parameter, which is applied, for example, by the turbocharger assembly, may involve measuring the control parameter.

[0013] Determining the current value of the control parameter may involve calculating the control parameter based on a predicted current exhaust manifold pressure.

[0014] The desirable limit value of the control parameter can be determined using a data model or a reference table, e.g., based on the desired pressure limit.

[0015] The predicted current exhaust manifold pressure can be forecast using the data model or the reference table. Using the same data model or reference table to determine the desirable limit of the control parameter and the predicted current exhaust manifold pressure improves the accuracy with which the error can be determined.

[0016] The desirable pressure limit can be determined according to a maximum inlet pressure limit of the turbocharger assembly; a maximum pressure ratio limit between an inlet and an outlet of the turbocharger assembly; and / or a maximum permissible rate of increase of exhaust gas pressure upstream of the turbocharger turbine.

[0017] The engine assembly may further include an exhaust gas recirculation (EGR) system designed to recirculate exhaust gases from a position upstream of the turbine of the turbocharger assembly to an inlet of the engine. The maximum permissible rate of increase in exhaust manifold pressure can be determined, at least in part, according to the operation of the EGR system, e.g., according to the flow rate of exhaust gases recirculated by the EGR system.

[0018] For example, the flow of exhaust gases within the EGR channel can be controlled by an EGR valve. The maximum permissible rate of increase can be determined, at least in part, by the position of the EGR valve.

[0019] The method may involve varying the operation of the EGR system, e.g. by controlling the position of the EGR valve, so that the flow rate of the recirculated exhaust gases remains essentially constant when the turbocharger arrangement is controlled.

[0020] The operation of the turbocharger assembly can be controlled according to a desired value of the control parameter or the adjusted limit value of the control parameter - whichever of these values ​​is lower.

[0021] The method may further include controlling the operation of the turbocharger assembly using a closed feedback loop when the exhaust manifold pressure exceeds the desired exhaust manifold pressure limit.

[0022] The method may include detecting a requirement for an increased amount of torque to be supplied by the power machine arrangement.

[0023] The procedure can be executed for a predetermined period after the detection of a requirement for an increased amount of torque, e.g., to control the operation of the turbocharger assembly so that the adjusted limit is not exceeded.

[0024] The turbocharger assembly can include a variable geometry turbine (VGT). The control parameter of the turbocharger assembly can correspond to the geometry of the VGT. For example, the control parameter can control a nozzle angle of the VGT.

[0025] The turbocharger assembly can include a turbocharger bypass channel designed to allow exhaust gases to bypass a turbine of the turbocharger assembly. The flow of exhaust gases through the bypass channel can be controlled by a bypass valve. The control parameter of the turbocharger assembly can correspond to the position of the bypass valve, e.g., between an open and a closed position.

[0026] According to another aspect of the present disclosure, a method for operating a motor vehicle is provided, the motor vehicle comprising the following: a vehicle arrangement and a control parameter of the vehicle arrangement that is controllable to control the operation of the vehicle arrangement, the method comprising: Determining a first limit value of the control parameter using a first procedure, based on a modeled value of a first operating parameter of the vehicle arrangement; Determining a second limit value of the control parameter using a second method based on a measured value of the first operating parameter; Determining an approval limit based on a second operating parameter of the power engine assembly, wherein the approval limit defines a limit of the value of the first limit that can be used to control the operation of the turbocharger assembly; and Control of the operation of the vehicle arrangement based on the first limit value if the first limit value is within the approval limit, or based on the stronger limitation, e.g., on the operation of the vehicle arrangement, the second limit value and the approval limit if the first limit value is outside the approval limit, e.g., in such a way that the imposed limit value is not exceeded.

[0027] The approval limit can be a minimum value of the control parameter whose application is permitted by the first procedure. The vehicle arrangement can be a turbocharger arrangement, e.g., provided in a motor vehicle engine arrangement.

[0028] According to another aspect of the present disclosure, a method for operating a power machine arrangement is provided, wherein the power machine arrangement comprises the following: a power machine; a turbocharger arrangement and a control parameter of the turbocharger arrangement that is controllable to control a level of gain provided by the turbocharger arrangement, the method comprising: Determining a first limit value of the control parameter using a first procedure, based on a modeled and measured value of the exhaust manifold pressure; Determining a second limit value of the control parameter using a second method, based on the respective other values ​​of the modeled and measured exhaust manifold pressure; Determining an approval limit based on an operating parameter of the power engine assembly, wherein the approval limit defines a limit of the value of the first limit that can be used to control the operation of the turbocharger assembly; and Control of the operation of the turbocharger assembly, based on the first limit value if the first limit value is within the approval limit, or based on the stronger limit, e.g., on the operation of the turbocharger assembly to provide boost to the engine, the second limit value and the approval limit if the first limit value is outside the approval limit, e.g., in such a way that the imposed limit value is not exceeded.

[0029] In this way, the operation of the turbocharger can be limited according to the first limit value determined using the first procedure for the extent of the approval limit. The approval limit can be a minimum value of the control parameter to which the first procedure can limit the control parameter.

[0030] The procedure can include determining a maximum permissible value of the control parameter based on another operating parameter of the power machine arrangement. For example, the maximum permissible value can be determined based on the current rotational speed and / or torque output of the power machine arrangement.

[0031] The approval limit can be defined relative to the maximum permissible value. In other words, the approval limit can define a maximum difference between the maximum permissible value and the first limit, within which the operation of the turbocharger assembly can be limited by the first method.

[0032] The first limit value can be determined using a data model or a reference table. The second limit value can be determined using a closed-loop feedback method, including proportional, integral, and / or differential control. For example, exhaust gas pressure at a turbocharger turbine inlet, such as within the exhaust manifold, can be fed back and compared to a maximum desired inlet pressure.

[0033] The first and second limit values ​​can be determined using separate controllers or modules. For example, the closed-loop feedback procedure can be implemented using a closed-loop feedback controller or module.

[0034] The approval limit can be determined based on one or more of the following values: of the engine torque, e.g. the rate of change of the engine torque; of the engine torque requested by a driver; of the exhaust pressure at an inlet of a turbine of the turbocharger; of the maximum exhaust pressure at the turbine inlet; of the level of turbocharger boost; the flow rate of exhaust gas through the turbine; and of the maximum permissible value of the control parameter.

[0035] The approval limit can be determined based on a rate of change in engine torque requested by a driver.

[0036] The first method can be the aforementioned method for operating a power machine arrangement.

[0037] According to another aspect of the present disclosure, software is provided which, when executed by a data processing device, causes the data processing device to perform one of the aforementioned procedures.

[0038] According to another aspect of the present disclosure, a power engine arrangement for a motor vehicle is provided, wherein the power engine arrangement comprises the following: a power machine; a turbocharger assembly and a control parameter of the turbocharger assembly that is controllable to control a level of boost provided by the turbocharger assembly; and one or more controllers designed to perform one of the aforementioned procedures.

[0039] The engine assembly may further include an exhaust gas recirculation system (EGR system) designed to return exhaust gases from a position in front of a turbine of the turbocharger assembly to an inlet of the engine.

[0040] A motor vehicle may include the aforementioned power engine arrangement.

[0041] To avoid unnecessary duplication and repetition of text in the description, certain features are described only with regard to one or more aspects or embodiments of the invention. However, it is understood that features described with regard to any aspect or embodiment of the invention may, where technically feasible, also be used with any other aspect or embodiment of the invention. Brief description of the drawings

[0042] For a better understanding of the present invention and to show more clearly how it can be implemented, the accompanying exemplary drawings are explained below, in which: Fig. 1 a schematic view of a power machine arrangement according to arrangements of the present disclosure; Fig. 2 a schematic view of a power machine arrangement according to a further arrangement of the present disclosure; Fig. 3 is a flowchart that represents a method for operating a power machine arrangement according to an arrangement of the present disclosure; Fig. 4 is a diagram of a measured and modeled exhaust manifold pressure, which is useful for understanding the in Fig. The procedure described in section 3 is; Fig. 5 is a flowchart that represents a method for operating a power machine arrangement according to a further arrangement of the present disclosure; and Fig. 6 is a flowchart that represents a method for operating a power machine arrangement according to a further arrangement of the present disclosure. Detailed description

[0043] With reference to Fig. 1 comprises a power engine arrangement 2 for a vehicle, e.g. a motor vehicle, a power engine 4, an intake system 6, an exhaust system 8, a high-pressure exhaust gas recirculation arrangement (high-pressure EGR arrangement) 10 and a turbocharger arrangement 14.

[0044] As in Fig. As shown in Figure 1, the intake system 6 comprises a low-pressure intake duct 6a, which is provided upstream of a compressor 14a of the turbocharger assembly. The compressor 14a is designed to increase the pressure of the air arriving at the compressor 14a from the low-pressure intake duct 6a to a boost pressure level. Intake air compressed by the compressor 14a enters a high-pressure intake duct 6b. Intake gases flow within the high-pressure intake duct 6b to an intake manifold 4a of the engine and can be drawn into cylinder 5 of the engine 4.

[0045] In the cylinders 5 of the engine 4, the intake gases are mixed with fuel, and the fuel is burned to provide energy for driving the engine 4. Exhaust gases produced by this combustion are discharged from the engine 4 via an exhaust manifold 4b into a high-pressure exhaust port 9b. Exhaust gases can flow through the high-pressure exhaust port 9b to a turbine 14b of the turbocharger assembly 14. The exhaust gases can be expanded by the turbine 14b so that they reach a low-pressure exhaust port 9a. The turbine 14b can be coupled to the compressor 14a via a shaft. Energy can be generated by the turbine 14b by expanding the exhaust gases through the turbine to drive the compressor 14a.

[0046] In the Fig. In the arrangement shown in Figure 1, turbine 14b is a variable geometry turbine (VGT) comprising variable inlet blades (not shown) arranged at an angle relative to a rotor (not shown) of the turbine. By varying the angle of the inlet blades relative to the rotor, the energy generated by turbine 14b, and consequently the energy supplied to compressor 14a, can be controlled. The level of boost provided by the turbocharger arrangement 14 can therefore be controlled by varying the angle of the variable inlet blades. The power unit arrangement 2 can include a controller 100 for controlling the operation of the VGT, e.g., by controlling the position of the VGT blades.

[0047] In some arrangements, the geometry of turbine 14b can be fixed, and the level of boost provided by the turbocharger arrangement 14 can be controlled by an alternative means. For example, the turbocharger arrangement 14, as in Fig. Figure 2 shows a bypass channel 14c designed to allow a portion of the exhaust gases to flow from the high-pressure outlet channel 9b to the low-pressure outlet channel 9a without passing through the turbine 14b. The flow of exhaust gases through the bypass channel 14c can be controlled by a bypass valve 14d, for example, a wastegate. By allowing a portion of the exhaust gases to bypass the turbine 14b, the power generated by the turbine 14b, and consequently the power available to drive the compressor 14a, can be reduced. The level of boost provided by the turbocharger assembly 14 can therefore be reduced.

[0048] In the Fig. In the arrangement shown in Figure 2, the controller 100 can be designed to control the position of the diverter valve 14d.

[0049] In other arrangements, the exhaust system 8 can include the VGT 14b and can also include the diversion channel 14c and the diversion valve 14d. In this arrangement, the energy generated by the turbine 14b can be controlled by varying the geometry of the turbine 14b and / or by varying the position of the diversion valve 14d.

[0050] Increasing the pressure of the intake air entering the engine 4, e.g., the boost level, allows a larger quantity of air to be drawn into the engine's cylinders, which in turn allows more fuel to be mixed with the air and burned. Burning more fuel within the engine 4 allows the engine to develop more power and torque to propel the vehicle. When a driver of the vehicle requests more power from the engine 4, for example, by pressing the vehicle's accelerator pedal (not shown), the turbocharger assembly 14 can be controlled to increase the boost level provided by the turbocharger assembly and, consequently, the power and torque produced by the engine.

[0051] The engine assembly 2 can further comprise a low-pressure EGR assembly 16, which includes a low-pressure EGR channel 16a designed to return a portion of the low-pressure exhaust gases to the intake system 6, e.g., to the low-pressure intake channel 6a. The flow of exhaust gases within the low-pressure EGR channel 16a can be controlled by the low-pressure EGR valve 16b.

[0052] The exhaust system 8 may further comprise one or more exhaust aftertreatment devices 18 located downstream of the turbine 14b. For example, the exhaust system 10 may include a NOx storage catalyst 18, a particulate filter 18, and / or a selective catalytic reduction device 18. The exhaust aftertreatment devices may be designed to reduce the concentrations of pollutants present in the exhaust gases.

[0053] One or more of the exhaust aftertreatment devices 18 can be controllable, e.g., to adjust the efficiency with which they remove pollutants from the exhaust gases. Controlling the operation of the exhaust aftertreatment devices can influence the mass flow rate of the exhaust gases through the exhaust system 8 and consequently through the turbine 14b.

[0054] Referring to the Fig. 1 and Fig. The high-pressure EGR device 10 comprises an EGR channel 12 designed to recirculate a portion of the exhaust gases exiting the engine 4 back to the intake system 6. The recirculated exhaust gases are mixed with intake air in the intake system 6 and can then be drawn back into the engine 4. A first end 12a of the high-pressure EGR channel can be connected to and in fluid communication with the high-pressure outlet channel 9b, for example, at a position upstream of the turbine 14b in the exhaust system 8. For example, the first end 12a of the high-pressure EGR channel can be connected to the outlet manifold 4b. A second end 12b of the high-pressure EGR channel can be connected to and in fluid communication with the high-pressure inlet channel 6b, for example, at a position in the intake system 6 between the compressor 14a and the engine 4.

[0055] The flow of exhaust gases within the high-pressure EGR channel 12 can be controlled by a high-pressure EGR valve 10a. The exhaust gas flow rate can depend on the position of the high-pressure EGR valve 10a and the pressure differential between the first and second ends 12a, 12b of the high-pressure EGR channel 12. For example, in the Fig. 1 and Fig. 2 arrangement shown then, when the pressure of exhaust gases within the high-pressure outlet channel 9b increases relative to the pressure of inlet gases within the high-pressure inlet channel 6b, the flow rate of exhaust gases within the high-pressure EGR channel 12 increases for a certain position of the high-pressure EGR valve 10a.

[0056] Increasing the flow rate of the EGR gases, either due to a change in the position of the high-pressure EGR valve or a change in the pressure differential along the high-pressure EGR channel 12, can lead to a reduction in the amount of intake air present in the intake gases drawn into the cylinders of engine 4, thereby reducing the amount of fuel that can be burned within the engine. Consequently, the energy produced by engine 4 can be reduced. Controlling the energy produced by the engine in this way can be beneficial, as it can lead to a reduction in the production of pollutants such as nitrogen oxides, compared to controlling engine 4 by other means, for example, by using an intake throttle valve.

[0057] As described above, when a driver of the vehicle requests increased power or torque, the operation of the turbocharger assembly 14 can be controlled to increase the level of boost provided. In the Fig. In the arrangement shown in 1, the turbocharger arrangement can be controlled to increase the level of gain by adjusting the angle of the variable blades of turbine 14b.

[0058] Adjusting the angle of the blades can reduce the area through which exhaust gases passing through turbine 14b can flow. Consequently, after controlling the turbine in this way, the pressure of the exhaust gases upstream of the turbine, e.g., within the exhaust manifold 4b, can increase.

[0059] Similarly, in the Fig. In the arrangement shown in Figure 2, the turbocharger arrangement can be controlled to increase the level of boost by closing the wastegate 14d. Closing the wastegate can reduce the flow area available for exhaust gases to bypass the turbine 14b, which can lead to an increase in the exhaust gas pressure within the high-pressure outlet 9b and / or the outlet manifold 4b.

[0060] In some arrangements, when a high level of torque is requested by the power unit 2 and the turbocharger arrangement 14 is controlled in response to the torque request by providing an increased level of boost, the exhaust gas pressure at an inlet of the turbine 14b of the turbocharger arrangement, e.g., within the exhaust manifold 4b and / or the high-pressure exhaust channel 9b, may approach the maximum design pressure of the turbine 14b. Furthermore, or alternatively, a pressure ratio between the inlet and an outlet of the turbine 14b may approach a maximum design ratio. As described above, if the maximum design pressure of the turbine 14b is exceeded, the turbine's power output may be reduced, the turbocharger may be damaged, and / or the turbocharger may require more intensive and / or more frequent maintenance.

[0061] Referring to Fig. 3 To reduce the risk that the pressure of exhaust gases at the turbine inlet exceeds the maximum design pressure or that the pressure ratio between the inlet and outlet of the turbine exceeds the maximum design ratio, the turbocharger arrangement can be controlled according to a method 300, e.g. by the control 100.

[0062] Method 300 comprises a first step 302 in which a desirable exhaust gas pressure limit P3max is determined for exhaust gases at the turbine inlet. The desirable exhaust gas pressure limit can be determined on the basis of at least the maximum design pressure, the maximum design ratio, and / or one or more other pressure limits, e.g., a dynamic pressure limit based on the operating conditions of the power plant arrangement.

[0063] In a second step 304 of the procedure 300, a desirable limit value of a control parameter VGTmax, to be applied to the turbocharger arrangement 14 in order to achieve the desired exhaust pressure limit, is predicted. The control parameter can correspond to any desirable control parameter of the turbocharger that is applied to control the operation of the turbocharger in order to influence the exhaust gas pressure at the inlet of the turbine 14b. For example, the control parameter can correspond to the angle of a variable vane of the VGT 14b or the position of the turbocharger bypass valve 14d.

[0064] In Fig. 4. Line L1 is a mapping of an actual exhaust manifold pressure on the vertical axis relative to the variable blade position on the horizontal axis, and line L2 is a mapping of the modeled exhaust manifold pressure on the vertical axis relative to a variable blade position on the horizontal axis, determined on the basis of a data model of the relationship between the VGT position and the exhaust manifold pressure.

[0065] The desirable limit VGTmax can be determined by reference to a data model or a reference table. For example, as in Fig. Figure 4 shows the desirable limit VGTmax determined using the desirable exhaust pressure limit P3max as an input to the model for the relationship between the VGT position and the exhaust manifold pressure.

[0066] In a third step 306 of the procedure 300, an error ΔVGTIim is determined in the desired limit value of the control parameter.

[0067] As in Fig. As shown in Figure 4 and with reference to Equation 1 below, the error ΔVGTIim can be determined by comparing a measured value of the current control parameter VGT1, e.g., measured using a blade angle sensor and / or a bypass valve position sensor of the turbocharger assembly, with a predicted current value of the control parameter VGT2. The predicted current value of the control parameter VGT2 can be determined by using a value of the exhaust pressure P3, measured using an exhaust manifold pressure sensor, as an input to the model for the relationship between the VGT position and the exhaust manifold pressure. ΔVGTlim=Gain*(VGT2−VGT1)

[0068] Alternatively, the error ΔVGTlim can be determined by comparing an estimated value of the control parameter VGT3 with the predicted current value of the control parameter. As in Fig. As shown in Figure 4, the estimated value of the control parameter VGT3 is calculated using a modeled value of the exhaust pressure P3, modeled as an input to the model for the relationship between the VGT position and the exhaust manifold pressure. As shown in Fig. As shown in Figure 4, using the estimated value of the control parameter VGT3 essentially results in the same value as calculated for the error ΔVGTlim.

[0069] As indicated in equation (1), the error ΔVGTlim can be multiplied by a gain value in some arrangements. The gain can be a constant value applied to all operating conditions of the power unit 2. Alternatively, the gain value can be adjusted according to a current operating parameter of the turbocharger arrangement 14 or the power unit 2. For example, the gain value can be determined according to the current exhaust pressure at the turbine inlet.

[0070] In a fourth step 308 of the procedure 300, the desired limit value of the control parameter VGTmax is adjusted based on the error ΔVGTlim, e.g. by adding / subtracting the error to / from the desired limit value to determine a corrected limit value, see equation (2) below. VGTcorrected=VGTmax−ΔVGTlim

[0071] In a fifth step 310 of the procedure 300, the operation of the turbocharger arrangement 14 is controlled such that the adapted limit value VGT corrected is not exceeded. For example, the turbocharger arrangement can be controlled using the minimum of the adapted desirable limit value VGT corrected and a desirable value of the control parameter, e.g., determined by a controller to provide a desirable turbocharger boost level.

[0072] By controlling the turbocharger assembly 14 based on a modeled value of the outlet pressure, the control response time can be shorter than a method that relies on measurements from a pressure sensor to determine whether a pressure limit has been reached. Furthermore, by controlling the turbocharger assembly 14 based on a modeled value of the outlet pressure, the control of the turbocharger assembly can be adapted to prevent exceeding the pressure limit before it is reached, for example, if the model determines that a value of the control parameter could cause the pressure limit to be exceeded.

[0073] Method 300 can further include controlling the operation of the turbocharger using a closed feedback loop, in which, for example, the exhaust gas pressure upstream of the turbocharger turbine is reported back to the controller 100 or another controller, such as a closed feedback control loop, when the exhaust gas pressure upstream of the turbine exceeds the desired pressure limit. This allows the pressure sensor and the feedback controller to be used as a backup in case the predicted values ​​or models used within Method 300 are incorrect.

[0074] In some arrangements, the procedure 300 may include a step in which a request for an increased amount of torque to be supplied by the power machine arrangement is detected. For example, when the driver of the vehicle presses the vehicle's accelerator pedal.

[0075] When a requirement for increased torque is detected, the steps of procedure 300 described above can be performed to control the operation of the turbocharger assembly 14 so that the desired exhaust pressure limit is not exceeded. The procedure can be performed to control the operation of the turbocharger assembly 14 for a predetermined period after the requirement is detected.

[0076] Before the demand is detected, the operation of the turbocharger assembly can be controlled using a previously proposed procedure, e.g., using a closed feedback control loop taking into account a pressure measurement of exhaust gases upstream of the turbine. After the predetermined period, the turbocharger assembly can revert to being controlled using the previously proposed procedure. Alternatively, procedure 300 can be executed repeatedly, e.g., independently of the torque demand.

[0077] The increase in exhaust gas pressure upstream of turbine 14b due to changes in the operation of the turbocharger assembly can occur at a higher rate than an increase in the pressure of the inlet gases within the high-pressure inlet channel 6b, which is due to the increased power supplied to the compressor 14a, e.g., by turbine 14b. This can lead to a change in the pressure differential between the first and second ends 12a, 12b of the high-pressure EGR channel 12, which can influence, e.g., increase, the flow rate of the EGR gases within the high-pressure EGR channel.

[0078] Consequently, if the driver demands an increase in the power supplied by the engine, the interaction between the operation of the turbocharger assembly 14 and the high-pressure EGR system 10 may result in an undesirable reduction in the power supplied to the engine 4 due to an increase in the EGR rate.

[0079] The position of the high-pressure EGR valve 10a can be controlled, at least partially, based on the pressure differential along the high-pressure EGR channel 12; consequently, the high-pressure EGR valve 10a can be controlled to compensate for this effect. However, if the driver demands a rapid increase in power to be provided by the engine, the high-pressure EGR valve 10a cannot be controlled quickly enough to compensate for the change in the pressure differential along the high-pressure EGR channel 12.

[0080] Referring to Fig. 5. With the aim of preventing an undesirable reduction in the power of the engine, a method 500 for operating an engine arrangement can be carried out in accordance with arrangements of the present disclosure.

[0081] The method comprises a first step 502 in which the pressure of exhaust gases upstream of the turbine 14b, e.g., within the high-pressure outlet channel 9b or the outlet manifold 4b, is determined. In a second step 504, the operation of the turbocharger assembly can be controlled, at least partially, according to the determined pressure.

[0082] The change in the pressure differential along the high-pressure EGR channel 12, which can result from a change in the operation of the turbocharger assembly 14, can depend on the exhaust gas pressure upstream of the turbine 12b, e.g., within the exhaust manifold 4b of the engine. Consequently, by controlling the operation of the turbocharger assembly 14, at least partially according to the exhaust manifold pressure, an undesirable reduction in the power supplied by the engine can be avoided.

[0083] The exhaust gas pressure upstream of turbine 14b can be determined using the pressure sensor provided at the high-pressure outlet duct 9b and / or the outlet manifold 4b. Alternatively, the exhaust gas pressure upstream of turbine 14b can be determined using the data model or the reference table.

[0084] In one arrangement of the present disclosure, the data model used allows the exhaust gas pressure upstream of turbine 14b to be determined based on the geometry of the VGT 14b and / or the position of the bypass valve 14d, the mass flow rate of exhaust gases through turbine 14b, and the pressure downstream of the turbine. However, in other arrangements, a data model or reference table can be used that allows the exhaust gas pressure upstream of turbine 14b to be determined based on a combination of the geometry of the VGT 14b and / or the position of the bypass valve 14d, the mass flow rate through the turbine, the pressure downstream of the turbine, the operating speed of the engine, the position of the high-pressure EGR valve 10b, the position of a low-pressure EGR valve 16b, and / or other suitable parameters of the engine arrangement 2.

[0085] Method 500 may further include determining a maximum permissible rate of increase in exhaust gas pressure downstream of the turbine. The operation of the turbocharger may be controlled such that the rate of increase in exhaust gas pressure upstream of the turbine is maintained at or below the maximum permissible rate.

[0086] The maximum permissible rate of pressure increase can be determined so that the high-pressure EGR system 10 can be controlled to adequately compensate for changes in the pressure differential along the high-pressure EGR channel 12. For example, by varying the position of the high-pressure EGR valve 10a to maintain the flow rate of the recirculated exhaust gases within the high-pressure EGR channel 12 at a desirable level.

[0087] The operation of the turbocharger assembly 14 can be controlled such that the exhaust gas pressure upstream of turbine 12b is maintained at or below the maximum permissible value. For example, the maximum permissible rate of pressure increase in the first step of procedure 300 can be used to determine the desirable exhaust gas pressure limit, which is then used within procedure 300 to control the operation of the turbocharger assembly.

[0088] In some embodiments, a nominal maximum value of the control parameter used to control the operation of the turbocharger 14, e.g., the angle of the VGT vane 14a or the setting of the turbocharger bypass valve 14d, can be determined based on a function of one or more operating parameters of the power unit assembly. For example, the nominal maximum value of the control parameter can be determined based on the rotational speed and / or power output of the power unit assembly.

[0089] The extent to which the adapted desirable limit, e.g., the value determined in step 4 308 of procedure 300, can be applied to override the nominal maximum value, e.g., to specify a more restrictive setting for the turbocharger assembly 14, can be determined based on one or more operating parameters of the power machine assembly, for example, the torque, the requested torque, and / or the exhaust manifold pressure.

[0090] In this way, the adjusted desirable limit value determined using method 300 can be used to control the turbocharger assembly 14 under certain desirable circumstances, such as when there is a high torque demand or when the exhaust manifold pressure is greater than a limit pressure, e.g., the desirable exhaust pressure limit. Under other circumstances, it may be found that the adjusted desirable limit value is too restrictive, and another control parameter, calculated using a different method and / or by a different control system, such as a closed-loop feedback control system, can be used to control the turbocharger assembly 14.

[0091] Referring to Fig.6, the operation of the turbocharger turbine 14b and / or the turbocharger bypass valve 14d is controlled using a method 600 in which a selection is made from a variety of control parameters and control parameter limits to control the operation of the turbocharger 14.

[0092] In a first step 602 of the procedure 600, the adjusted desirable limit value of the control parameter is determined, e.g. using the procedure 300 described above.

[0093] In a second step, an approval limit is determined for the adjusted desirable limit value. The approval limit can be determined based on a function of one or more operating parameters of the power machine arrangement. For example, the torque requirement can be based on a function of the power machine torque requirement, such as the rate of torque change within a certain time and a difference between the outlet pressure and the maximum design pressure.

[0094] The approval limit can be defined as a minimum value of the control parameter that is applied as a limit to the control of the turbocharger assembly 14, e.g., by procedure 300. In other words, the approval limit can be a minimum value of the adjusted desirable limit VGT corrected, which can be applied by procedure 300 to control the operation of the turbocharger assembly. Alternatively, the approval limit can be defined as a maximum permissible difference between the nominal maximum value of the control parameter and the adjusted desirable limit.

[0095] In a third step (606), a capped limit of the control parameter is calculated by comparing the adjusted desirable limit, the approval limit, and optionally the nominal maximum value. For example, if the approval limit defines the approved minimum value of the control parameter, the capped limit is calculated using the maximum of the adjusted desirable limit and the approval limit.

[0096] In a fourth step (608), a control parameter value for the closed loop is determined using a closed feedback control loop. The control parameter value for the closed loop can be based on a measured value of the outlet pressure, for example, the outlet manifold pressure, and the maximum design pressure of the turbocharger.

[0097] In a fifth step 610, the maximum nominal value of the control parameter is determined as described above (unless it is already available due to the determination of the approval limit or the capped limit).

[0098] The procedure 600 may include a sixth step 612 in which a further control parameter value is calculated based on one or more measured and / or modeled operating characteristics of the power machine arrangement, for example the power machine speed, the power machine load, the inlet and / or outlet pressure and / or any other operating characteristics of the power machine arrangement.

[0099] In a seventh step 614 of procedure 600, a final control parameter value is determined based on the control parameter values ​​determined in the other steps of the procedure. For example, the final limit value can be determined as the minimum value of the clipped limit value, the closed-loop control parameter value, the maximum nominal value, and / or the other control parameter value.

[0100] The final limit value can be used to control the operation of the turbocharger assembly, e.g., to ensure that the value of the control parameter does not exceed the limit value.

[0101] Method 600 provides a smooth transition between methods for controlling the operating limit of the turbocharger assembly, such as Method 300, and a closed-loop feedback control method, depending on which method is considered most suitable for the current operating regime of the power unit assembly. For example, Method 300 can be used during dynamic maneuvers to reduce the risk of exceeding the turbine inlet pressure limit, and under constant conditions, closed-loop feedback control can be used to maintain the turbine inlet pressure at a desired value.

[0102] The following numbered statements are also part of the present disclosure: Statement 1. A method for operating a power machine arrangement, wherein the power machine arrangement comprises the following: a power machine; a turbocharger arrangement and a control parameter of the turbocharger arrangement that is controllable to control a level of gain provided by the turbocharger arrangement, the method comprising: Determining a desirable pressure limit of exhaust gases upstream of the turbine of the turbocharger assembly; Predicting a desirable limit value of the control parameter to be applied to the turbocharger arrangement in order to achieve the desired pressure limit; Determining an error within the desired limit of the control parameter; Setting the desired limit value of the control parameter based on the error; and Controlling the operation of the turbocharger assembly so that the adjusted limit value is not exceeded. Statement 2. The procedure according to statement 1, wherein determining the error in the desirable limit of the control parameter comprises the following: Predicting a current value of the control parameter based on a current pressure of exhaust gases upstream of the turbine; Determining a current value of the control parameter; and Determining the error between the predicted current value of the control parameter and the actual value of the control parameter. Statement 3. The procedure according to statement 2, wherein determining the current value of the control parameter includes measuring the control parameter. Statement 4. The procedure according to statement 2, wherein determining the current value of the control parameter includes calculating the control parameter based on a predicted current exhaust manifold pressure. Statement 5. The procedure according to one of the preceding statements, wherein the desirable limit value of the control parameter is determined using a data model or a reference table. Statement 6. The procedure according to statements 5 and 4, wherein the predicted current exhaust manifold pressure is determined using the data model or the reference table. Statement 7. The procedure according to one of the preceding statements, wherein the desirable pressure limit is determined according to at least one of the following parameters: a maximum inlet pressure limit of the turbocharger assembly; a maximum pressure ratio limit between an inlet and an outlet of the turbocharger assembly; and a maximum permissible rate of increase in exhaust gas pressure upstream of the turbocharger turbine. Statement 8. The method according to Statement 7, wherein the engine assembly further comprises an exhaust gas recirculation system (EGR system) designed to recirculate exhaust gases from a position upstream of the turbine of the turbocharger assembly to an inlet of the engine, wherein the maximum permissible rate of increase of the exhaust manifold pressure is determined at least partially according to the operation of the EGR system. Statement 9. The procedure according to statement 8, the procedure further comprising the following: Varying the operation of the EGR system so that the flow rate of the recirculated exhaust gases remains essentially constant when the turbocharger arrangement is controlled. Statement 10. The procedure according to one of the preceding statements, wherein the operation of the turbocharger arrangement is controlled according to the minimum of the following values: a current value of the control parameter; and the adjusted limit value of the control parameter. Statement 11. The method according to any of the preceding statements, wherein the method further comprises controlling the operation of the turbocharger arrangement using a closed feedback loop when the exhaust manifold pressure exceeds the desirable exhaust manifold pressure limit. Statement 12. The procedure according to any of the preceding statements, wherein the procedure comprises the following: Identifying a requirement for an increased amount of torque to be supplied by the power machine arrangement. Statement 13. The procedure according to Statement 12, wherein the procedure is carried out for a predetermined period after the recognition of the requirement for an increased amount of torque. Statement 14. The method according to any of the preceding statements, wherein the turbocharger arrangement comprises a variable geometry turbine (VGT); and wherein the control parameter of the turbocharger arrangement corresponds to the geometry of the VGT. Statement 15. The method according to any of the preceding statements, wherein the turbocharger assembly comprises a turbocharger assembly bypass channel designed to allow exhaust gases to bypass a turbine of the turbocharger assembly, wherein the flow of exhaust gases through the bypass channel is controlled by a bypass valve; and wherein the control parameter of the turbocharger assembly corresponds to the position of the bypass valve. Statement 16. A method for operating a power machine arrangement, wherein the power machine arrangement comprises the following: a power machine; a turbocharger arrangement and a control parameter of the turbocharger arrangement that is controllable to control a level of gain provided by the turbocharger arrangement, the method comprising: Determining a first limit value of the control parameter using a first procedure, based on a modeled and measured value of the exhaust manifold pressure; Determining a second limit value of the control parameter using a second method, based on the respective other values ​​of the modeled and measured exhaust manifold pressure; Determining an approval limit based on an operating parameter of the power engine assembly, wherein the approval limit defines a limit of the value of the first limit that can be used to control the operation of the turbocharger assembly; and Controlling the operation of the turbocharger assembly based on the first limit value if the first limit value is within the approval limit, or based on the stronger limitation of the second limit value and the approval limit if the first limit value is outside the approval limit. Statement 17. The procedure according to Statement 16, the procedure further comprising the following: Determining a maximum permissible value of the control parameter based on another operating parameter of the power machine arrangement. Statement 18. The procedure according to statement 17, whereby the approval limit is defined relative to the maximum permissible value. Statement 19. The procedure according to any of statements 16 to 18, wherein the first limit is determined using a data model or a reference table, and the second limit is determined using a closed-loop feedback procedure, including proportional, integral and / or differential control. Statement 20. The procedure according to one of statements 16 to 19, whereby the approval limit is determined on the basis of: of the engine torque; of the engine torque requested by a driver; of the exhaust pressure at an inlet of a turbine of the turbocharger; of the maximum exhaust pressure at the turbine inlet; of the level of turbocharger boost; the flow rate of exhaust gas through the turbine; and / or of the maximum permissible value of the control parameter. Statement 21. The procedure according to one of statements 16 to 20, wherein the approval limit is determined based on a change in engine torque requested by a driver: Statement 22. The procedure according to one of statements 16 to 21, the first procedure being the procedure according to one of statements 1 to 15. Statement 23. Software which, when executed by a data processing device, causes the data processing device to execute the procedure according to any of the preceding statements. Statement 24. Power engine arrangement for a motor vehicle, wherein the power engine arrangement comprises the following: a power machine; a turbocharger assembly and a control parameter of the turbocharger assembly that is controllable to control a level of boost provided by the turbocharger assembly; and one or more controllers designed to carry out the procedure according to any of the preceding statements. Statement 25. A motor vehicle comprising the power engine arrangement from Statement 24.

[0103] It is understood by a person skilled in the art that the invention, although described by way of example with reference to one or more exemplary examples, is not limited to the disclosed examples and that alternative examples could be formed without deviating from the scope of protection of the invention as defined by the attached claims.

Claims

[1] A method for operating a power machine arrangement, wherein the power machine arrangement comprises: a power machine; a turbocharger arrangement and a control parameter of the turbocharger arrangement that is controllable to control a level of gain provided by the turbocharger arrangement, the method comprising: Determining a desirable pressure limit of exhaust gases upstream of the turbine of the turbocharger assembly; Predicting a desirable limit value of the control parameter to be applied to the turbocharger arrangement in order to achieve the desired pressure limit; Determining an error within the desired limit of the control parameter; Setting the desired limit value of the control parameter based on the error; and Controlling the operation of the turbocharger assembly so that the adjusted limit value is not exceeded, characterized by, that Determining the error within the desired limit of the control parameter includes the following: Predicting a current value of the control parameter based on a current pressure of exhaust gases upstream of the turbine; Determining a current value of the control parameter; and Determining the error between the predicted current value of the control parameter and the actual value of the control parameter. [2] Method according to claim 1, wherein determining the current value of the control parameter comprises calculating the control parameter based on a predicted current exhaust manifold pressure. [3] Method according to any of the preceding claims, wherein the desirable pressure limit is determined according to at least one of the following parameters: a maximum inlet pressure limit of the turbocharger assembly; a maximum pressure ratio limit between an inlet and an outlet of the turbocharger assembly; and a maximum permissible rate of increase in exhaust gas pressure upstream of the turbocharger turbine. [4] Method according to claim 3, wherein the engine arrangement further comprises an exhaust gas recirculation system (EGR system) designed to recirculate exhaust gases from a position upstream of the turbine of the turbocharger arrangement to an inlet of the engine, wherein the maximum permissible rate of increase of the exhaust manifold pressure is determined at least partially according to the operation of the EGR system. [5] The method of claim 4, wherein the method further comprises: Varying the operation of the EGR system so that the flow rate of the recirculated exhaust gases remains essentially constant when the turbocharger arrangement is controlled. [6] Method according to any of the preceding claims, wherein the operation of the turbocharger arrangement is controlled according to the minimum of the following values: a desired value of the control parameter; and the adjusted limit value of the control parameter. [7] Method according to any of the preceding claims, wherein the method further comprises controlling the operation of the turbocharger arrangement using a closed feedback loop when the exhaust manifold pressure exceeds the desirable exhaust manifold pressure limit. [8] A method according to any of the preceding claims, wherein the method comprises: Identifying a requirement for an increased amount of torque to be supplied by the power machine arrangement. [9] Method according to claim 8, wherein the method is carried out for a predetermined period of time after the detection of the requirement for an increased amount of torque. [10] Method according to any of the preceding claims, wherein the turbocharger arrangement comprises a variable geometry turbine (VGT); and wherein the control parameter of the turbocharger arrangement corresponds to the geometry of the VGT. [11] Method according to any of the preceding claims, wherein the turbocharger arrangement comprises a turbocharger arrangement bypass channel designed to allow exhaust gases to bypass a turbine of the turbocharger arrangement, wherein the flow of exhaust gases through the bypass channel is controlled by a bypass valve; and wherein the control parameter of the turbocharger arrangement corresponds to the position of the bypass valve. [12] Software which, when executed by a data processing device, causes the data processing device to execute the method according to any of the preceding claims. [13] Power engine arrangement for a motor vehicle, the power engine arrangement comprising: a power machine; a turbocharger assembly and a control parameter of the turbocharger assembly that is controllable to control a level of boost provided by the turbocharger assembly; and one or more controllers designed to execute the method according to any one of claims 1 to 11. [14] Motor vehicle comprising the power engine arrangement according to claim 13.

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