Control module and method for controlling an air charging system of a vehicle

Abstract

Control module (200) comprising: a dynamic target selection module (220) configured to (i) receive an intake manifold pressure setpoint and a measured intake manifold pressure, (ii) select between the intake manifold pressure setpoint and the measured intake manifold pressure, and (iii) output a selected intake manifold pressure setpoint based on the selection, and a multivariable control module (216) configured to (i) receive at least one target setpoint based on the selected intake manifold pressure setpoint, and (ii) control operation of an air charging system of a vehicle (100) based at least on the at least one target setpoint.

Description

INTRODUCTION

[0001] The present invention relates to exhaust gas recirculation (EGR) and, more particularly, to a control module and method for controlling an air charging system of a vehicle to achieve a target compressor and target combustion gas ratio for diesel air charging in an EGR system.

[0002] For background information, please refer to JP 2006 - 152 932 A, which describes how to control the throttle valve based on boost pressure and manifold pressure. Specifically, the actual boost pressure value is used in a certain transient condition; otherwise, the setpoint value is used.

[0003] Various parameters of an internal combustion engine are controlled according to desired outputs such as engine speed, engine load, output torque, emissions, etc. Controlled parameters include air flow, fuel flow, and intake and exhaust valve timing.

[0004] In some engine systems, charge air may be provided to the engine to provide increased flow of air to the engine relative to a naturally aspirated intake system to increase engine output. According to some examples, an air boost system, such as a turbocharging system, uses pressure in an exhaust system of the engine to drive a compressor to provide the charge air to the engine. According to other examples, a boosting device uses mechanical power from the engine to drive a compressor to provide the charge air. An engine system may include both a turbocharging system and a boosting device. Engine control methods control the charge air to control the resulting combustion in the engine and the resulting output of the engine. According to some examples, EGR is controlled to optimize air boost. SUMMARY

[0005] According to the invention, a control module is presented which is characterized by the features of claim 1. The control module includes a dynamic target selection module configured to receive an intake manifold pressure setpoint and a measured intake manifold pressure, select between the intake manifold pressure setpoint and the measured intake manifold pressure, and output a selected intake manifold pressure setpoint based on the selection. A multivariable control module is configured to receive at least one target setpoint based on the selected intake manifold pressure setpoint and to control operation of an air induction system of a vehicle based at least on the at least one target setpoint.

[0006] According to other features, the dynamic target selection module is configured to output the selected intake manifold pressure setpoint based on a difference between the intake manifold pressure setpoint and the measured intake manifold pressure.

[0007] In other features, the dynamic target selection module is configured to output the selected intake manifold pressure setpoint further based on a comparison between the difference between the intake manifold pressure setpoint and the measured intake manifold pressure and a threshold.

[0008] In other features, a volumetric efficiency module is configured to generate a total cylinder mass flow target based on the selected intake manifold pressure setpoint.

[0009] In other features, the volumetric efficiency module is configured to generate the cylinder total mass flow target further based on a volumetric efficiency calibration map.

[0010] In other features, a static setpoint transformation module is configured to generate the at least one target setpoint based on the selected intake manifold pressure setpoint, a mass air flow setpoint, and a total cylinder mass flow target.

[0011] According to other features, the at least one target setpoint includes a target compressor ratio setpoint and a target combustion gas ratio setpoint.

[0012] According to other features, the static setpoint transformation module is configured to calculate the target combustion gas ratio setpoint based on the cylinder total mass flow target.

[0013] According to the invention, a method for controlling an air charging system of a vehicle is further presented, which is characterized by the features of claim 6.

[0014] The method includes receiving an intake manifold pressure setpoint and a measured intake manifold pressure, selecting between the intake manifold pressure setpoint and the measured intake manifold pressure, outputting a selected intake manifold pressure setpoint based on the selection, receiving at least one target setpoint based on the selected intake manifold pressure setpoint, and controlling operation of the air charging system based on the at least one target setpoint.

[0015] In other features, the method further includes outputting the selected intake manifold pressure setpoint based on a difference between the intake manifold pressure setpoint and the measured intake manifold pressure.

[0016] In other features, the method further includes outputting the selected intake manifold pressure setpoint further based on a comparison between (i) the difference between the intake manifold pressure setpoint and the measured intake manifold pressure and (ii) a threshold.

[0017] In other features, the method further includes generating a total cylinder mass flow target based on the selected intake manifold pressure setpoint.

[0018] In other features, the method further includes generating the cylinder total mass flow target further based on a volumetric efficiency calibration map.

[0019] In other features, the method further includes generating the at least one target setpoint based on the selected intake manifold pressure setpoint, a mass air flow setpoint, and a total cylinder mass flow target.

[0020] According to other features, the at least one target setpoint includes a target compressor ratio setpoint and a target combustion gas ratio setpoint.

[0021] In other features, the method further includes calculating the target combustion gas ratio setpoint based on the cylinder total mass flow target.

[0022] A control module includes a dynamic target selection module configured to receive an intake manifold pressure setpoint and a measured intake manifold pressure, select between the intake manifold pressure setpoint and the measured intake manifold pressure, and output a selected intake manifold pressure setpoint based on the selection, a volumetric efficiency module configured to generate a total cylinder mass flow target based on the selected intake manifold pressure setpoint and a volumetric efficiency calibration map, a static setpoint transformation module configured to generate a target compressor ratio setpoint and a target combustion gas ratio setpoint based on the selected intake manifold pressure setpoint, an air mass flow setpoint, and a total cylinder mass flow target, and a multivariable control module configured toto control the operation of an air charging system of a vehicle based on the target compressor ratio setpoint and the target combustion gas ratio setpoint.,

[0023] Further areas of applicability of the present invention will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for illustrative purposes only. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be more fully understood from the detailed description and the accompanying drawings, in which: Fig. 1 is a functional block diagram of an exemplary engine system; Fig. 2 is a functional block diagram of an exemplary control module; Fig. 3A, Fig. 3B and Fig. 3C Results of example calibrations of the dynamic target selection logic; Fig. 4 an example representation of the selected boost pressure output for respective calibrations; and Fig. 5 steps of an example method for generating a target intake manifold pressure setpoint.

[0025] In the drawings, reference symbols may be used multiple times to identify similar and / or identical elements. DETAILED DESCRIPTION

[0026] Some engine control systems implement exhaust gas recirculation (EGR) to control combustion and engine output. For example, exhaust gas may be directed into an engine intake manifold to be reburned. Air boosting / air treatment systems manage the flow of intake air and EGR in engines. The air boosting systems are configured to operate according to charge air composition targets (e.g., an EGR fraction target) to meet emissions targets and total available air targets (e.g., a charge air mass flow) to achieve desired power and torque targets. In general, system actuators that significantly affect EGR flow can also affect boost flow, while system actuators that significantly affect boost flow can also affect EGR flow.Accordingly, air-charging systems can correspond to multi-input-multi-output (MIMO) systems with coupled input-output response circuits.

[0027] MIMO systems, such as coupled-input air-induction systems (i.e., with coupled input-output response circuits), can operate over a wide range of parameters, including variable engine speeds, torque outputs, and fueling and timing schedules. In some examples, accurate transfer functions and / or the computational power required for a standard decoupling calculation for the system are not available. Multi-path EGR control allows the system to operate at higher EGR rates at higher boost levels, but compromises compressor flow and compressor performance.

[0028] Various calibrations and calculations corresponding to the control of the air-charging system may be inaccurate during transient periods, such as gear shifting, resulting in poor control (e.g., premature opening of an EGR valve). As an example, air-charging systems may operate according to inputs corresponding to various setpoints that may correspond to desired performance parameters. The setpoints may, for example, include an intake manifold pressure setpoint. pBoost¯ and an air mass flow setpoint WAir¯ contain.

[0029] The setpoints may be provided to a static setpoint transformation module configured to transform the setpoints into target setpoints for the air-induction system (e.g., target setpoints of a multivariable control module of the air-induction system). For example, the static setpoint transformation module may implement a transformation function to transform the input setpoints into target setpoints. The transformation may correspond to an approximate transformation of the input setpoints into the target setpoints. Using the transformation function to generate the target setpoints, such as a combustion gas ratio (BGR), based on the input setpoints may result in inaccurate control and degradation of drivability, such as premature opening of the EGR valve, increased smoke generation, slow torque response, and / or increased NOx emissions.

[0030] According to one example, the static setpoint transformation module outputs target setpoints that represent a compressor pressure ratio setpoint βc¯, a combustion gas ratio intake manifold setpoint BGRIntk¯ and a cylinder total mass flow target WCylTot¯ included. The compressor pressure ratio setpoint βc¯ can according to βc¯=pBoost¯pComprUp be calculated, where p ComprUp a pressure upstream of the compressor. The combustion gas ratio BGRIntk¯ can according to BGRIntk¯=WCylTot¯−WAir¯WCylTot¯BGRExh¯ be calculated, where BGRExh¯ corresponds to a combustion gas ratio exhaust manifold setpoint. The cylinder total mass flow target WCylTot¯ can according to WCylTot¯=pBoost¯WCylTotActualpBoostMeas be calculated, where WCylTotActual corresponds to an actual (e.g. as calculated and / or measured) cylinder total mass flow and pBoostMeas corresponds to a measured intake manifold pressure.

[0031] According to some examples, air-induction systems may implement one or more approaches to adjust setpoints to compensate for control inaccuracies (i.e., scale up or down). For example, different setpoints may be compensated by a multiplier, by an offset, etc., using a lookup table or map-based approach. However, traditional table- or map-based approaches require complex, time-consuming, and computationally intensive calibration processes due to multiple dependencies between multivariable control inputs and outputs.

[0032] Air boost control systems and air boost control methods according to the principles of the present invention are configured to compensate for target setpoints provided to the multivariable control module during transient time periods.

[0033] In Fig. 1, a vehicle 100 includes an engine system 104 configured to control an engine 108 that combusts an air / fuel mixture to produce drive torque. The engine 108 may be a diesel, gasoline, or other type of internal combustion engine. The engine system 104 includes a turbocharger 112 and / or a supercharging device 116. Air is provided to the engine 108 via an intake 120, which may include sensors (not shown) such as a mass air flow sensor.

[0034] A compressor 124 of the turbocharger 112 compresses the air provided to the engine 108. The turbocharger 112 may be a variable geometry turbocharger (VGT) or another type of turbocharger. A turbine 128 of the turbocharger 112 controls the flow, velocity, and / or pressure of the air within the compressor 124. The air output from the compressor 124 is provided to the booster 116. A bypass valve 132 may be actuated to selectively allow the compressed air to bypass the booster 116 to be provided directly to an intake manifold 136 of the engine 108.

[0035] The compressed air is combined with fuel in the cylinders 140 of the engine 108 and combusted to produce drive torque. Although four of the cylinders 140 are shown, the engine 108 may include any suitable number of cylinders (e.g., between two and sixteen) arranged in various configurations. Exhaust gas exits the engine 108 via an exhaust manifold 144, being input to the turbine 128 before being expelled from the vehicle 100 through one or more exhaust treatment devices. According to some examples, an EGR valve 152 may be selectively opened and closed to mix the exhaust gas with the compressed air provided to the intake manifold 136.

[0036] A control module (e.g., an engine control module) 156 controls components of the engine system 104 (e.g., such as the turbocharger 112) and actuators, including the bypass valve 132 and the EGR valve 152, based on inputs such as sensed or measured data, modeled data, vehicle inputs (e.g., power requests and / or setpoints), etc.

[0037] For example, a pressure sensor 160 senses a pressure of air provided by the turbocharger 112 and accordingly provides a first pressure signal to the control module 156. Similarly, a pressure sensor 164 senses a pressure of air provided by the boost device 116 and accordingly provides a second pressure signal to the control module 156. An air temperature sensor 168 senses a temperature of air entering the engine system 104 and accordingly provides an intake air temperature signal to the control module 156. A coolant temperature sensor 172 senses a temperature of cooling fluid in the engine 108 and accordingly provides a coolant temperature signal to the control module 156. An engine speed sensor 176 senses a speed of the engine 108 and accordingly provides an engine speed signal to the control module 156.

[0038] The control module 156 controls the engine system 104 (including multivariable control of an air boost system) according to the received signals and / or other inputs. An example configuration of the control module 156 is described in more detail in US patent application US 2019 / 0 316 533 A1. As described in more detail below, the control module 156 is further configured, in accordance with the principles of the present invention, to improve the accuracy of the compressor pressure ratio and combustion gas ratio setpoints.

[0039] An exemplary control module 200 (e.g., corresponding to control module 156) is described in more detail in Fig. 2. The control module 200 includes a static setpoint transformation module 204 configured to transform setpoints 208 into target setpoints 212 for the air charging system (e.g., target setpoints of a multivariable control module 216 of the air charging system). For example, the static setpoint transformation module 204 may implement a transformation function for transforming the input setpoints 208 into the target setpoints 212. For example only, the input setpoints 208 may include an intake manifold pressure setpoint pBoost¯ and an air mass flow setpoint WAlr¯ and the target setpoints 212 may contain a compressor pressure ratio setpoint βc¯ and a combustion gas ratio BGRIntk¯ contain.

[0040] Further, in accordance with the principles of the present invention, the control module 200 includes a dynamic target selection module (DTS module 220) and a volumetric efficiency module 224. For example only, the static setpoint transformation module 204 receives the mass air flow setpoint WAlr¯ and the DTS module 220 receives the intake manifold pressure setpoint pBoost¯ and a measured intake manifold pressure pBoostMeas. The DTS module 220 optionally outputs a selected intake manifold pressure setpoint pBoostSelected (which corresponds, for example, to a selected boost pressure), either the intake manifold pressure setpoint pBoost¯ or the measured intake manifold pressure pBoostMeas, For example, the DTS module 220 selects between the intake manifold pressure setpoint pBoost¯ and the measured intake manifold pressure pBoostMeas according to pBoostSelected={pBoostMeasfor (pBoost¯−pBoostMeas)>KBoostDevThr∗pBoost¯for (pBoost¯−pBoostMeas) <KBoostDevThr∗, where KBoostDevThr∗ is an adjustable constant corresponding to a boost pressure deviation calibration threshold.

[0041] The boost pressure deviation calibration threshold corresponds to calibrating a transition logic to instead of the intake manifold pressure setpoint being set to a selected value KBoostDevThr∗ to select an actual boost pressure value (ie the measured intake manifold pressure). In other words, if a difference between the intake manifold pressure setpoint pBoost¯ and the measured intake manifold pressure pBoostMeas larger than KBoostDevThr* the DTS module 220 selects the measured intake manifold pressure pBoostMeas and outputs it. Conversely, the DTS module 220 selects the intake manifold pressure setpoint pBoost¯ and outputs it if the difference between the intake manifold pressure setpoint pBoost¯ and the measured intake manifold pressure pBoostMeas less than KBoostDevThr* In this way, the actually measured intake manifold pressure pBoostMeas than the selected intake manifold pressure setpoint pBoostSelected used until the actually measured intake manifold pressure pBoostMeas within a (as defined by KBoostDevThr* defined) threshold distance from the commanded intake manifold pressure setpoint pBoost¯ To switch back and forth between the intake manifold pressure setpoint pBoost¯ and the measured intake manifold pressure pBoostMeas To avoid this, a hysteresis logic can be implemented.

[0042] The selected intake manifold pressure setpoint output by the DTS module 220 pBoostSelected is provided to the volumetric efficiency module 224. The volumetric efficiency module 224 is configured to, based on the selected intake manifold pressure setpoint pBoostSelected to implement a volumetric efficiency model to achieve a compensated cylinder total mass flow target WCylTotNew¯ For example, the volumetric efficiency module 224 calculates the compensated cylinder total mass flow target WCylTotNew¯ according to WCylTotNew¯=ην0VdnEng120 RTipBoostSelected, where η v0 corresponds to a delivery level calibration map, V d is an engine displacement, n Eng is an engine speed, R is the universal gas constant and T ian intake manifold gas temperature.

[0043] The static setpoint transformation module 204 calculates based on the air mass flow setpoint pBoostSelected, the selected intake manifold pressure setpoint WAlr¯ and the compensated cylinder total mass flow target WCylTotNew¯ compensated target setpoints (e.g. setpoints of the target compressor pressure ratio βc¯ and the combustion gas ratio BGRIntk¯). For example, the static setpoint transformation module 204 calculates the compensated target combustion gas ratio setpoint BGRIntk¯ according to BGRIntk¯=WCylTotNew¯−WAlr¯WCylTotNew¯BGRExh¯. In this manner, compensated setpoints calculated in accordance with the principles of the present invention are provided to the multivariable control module 216.

[0044] Fig. 3A, Fig. 3B and Fig. 3C show results of exemplary calibrations of a dynamic target selection logic that uses different target combustion gas ratio setpoints BGRIntk¯ correspond (e.g. based on the volumetric efficiency as determined using the volumetric efficiency calibration map η v0 calculated compensated cylinder total mass flow target WCylTotNew¯), during a transitional period.

[0045] For example, by setting a boost pressure deviation calibration threshold KBoostDevThr∗ Different calibrations can be achieved based on the desired results. Fig. 3A illustrates NOx emissions for three different calibrations: a first calibration 300 configured to minimize NOx emissions; a second calibration 304 configured to minimize soot emissions; and a third calibration 308 configured to strike a trade-off (i.e., a balance) between minimizing NOx emissions and soot emissions. For example, the third calibration 308 results in higher NOx emissions than the first calibration 300, but lower NOx emissions than the second calibration 304.

[0046] Fig. 3B and Fig. 3C represent the air flow and instantaneous torque, respectively, for the first calibration 300, for the second calibration 304, and for the third calibration 308. As in Fig. For example, as shown in Figure 3B, the first calibration 300 results in a slow and uneven increase in airflow compared to the second calibration 304. Consequently, the instantaneous torque for the first calibration 300 is reduced by no less than 40 Nm (e.g., 21%) relative to the second calibration 304. Conversely, the airflow for the third calibration 308 is similar to that of the second calibration 304 and results in a reduction in instantaneous torque of only 8 Nm (e.g., 4%).

[0047] Fig. 4 illustrates exemplary boost pressure responses and selected boost pressure outputs of the DTS module 220 corresponding to the first calibration 300, the second calibration 304, and the third calibration 308. An exemplary boost pressure response corresponding to the commanded intake manifold pressure setpoint pBoost¯ is shown at 400. A boost pressure response corresponding to the selected intake manifold pressure setpoint pBoostSelected is shown at 404. As described above, the selected intake manifold pressure setpoint pBoostSelected the actually measured intake manifold pressure pBoostMeas (e.g. according to the third calibration 308) until the actually measured intake manifold pressure pBoostMeas, as shown at 408, within the threshold distance KBoostDevThr* the commanded intake manifold pressure setpoint pBoost¯ Accordingly, the boost pressure response of the selected intake manifold pressure setpoint pBoostSelected 404 at 408 abruptly to adapt to the boost pressure response corresponding to the commanded intake manifold pressure setpoint pBoost¯ 400 corresponds to.

[0048] Now based on Fig.5, an exemplary method 500 for generating a target intake manifold pressure setpoint according to the present invention begins at 504. At 508, the method 500 determines calibrated values ​​corresponding to the setpoint calculation. For example, the calibrated values ​​may be the volumetric efficiency calibration map η v0 and the threshold distance KBoostDevThr* As described above, the calibrated values ​​can be determined according to the desired NOx emission and soot levels and the desired torque response.

[0049] At 512, the method 500 (e.g., the control module 200) receives one or more commanded setpoints (e.g., the intake manifold pressure setpoint pBoost¯ and the air mass flow setpoint WAir¯ ) and the measured intake manifold pressure pBoostMeas. At 516, the method 500 (e.g., the DTS module 220) selects based on the threshold distance KBoostDevThr* between the intake manifold pressure setpoint pBoost¯ and the measured intake manifold pressure pBoostMeas and there is the selected intake manifold pressure setpoint pBoostSelected accordingly.

[0050] At 520, method 500 (e.g., volumetric efficiency module 224) calculates, based on the selected intake manifold pressure setpoint, pBoostSelected the compensated cylinder total mass flow target WCylTotNew¯. At 524, the method 500 (e.g., the static setpoint transformation module 204) calculates, based on the compensated cylinder total mass flow target WCylTotNew¯, the selected intake manifold pressure setpoint pBoostSelected and the air mass flow setpoint WAir¯ the target setpoints including the compressor pressure ratio setpoint βc¯ and the combustion gas ratio setpoint BGRIntk¯.

[0051] At 528, the method 500 (e.g., the multivariable control module 216) controls

Claims

[1] Control module (200) comprising: a dynamic target selection module (220) configured to (i) receive an intake manifold pressure setpoint and a measured intake manifold pressure, (ii) select between the intake manifold pressure setpoint and the measured intake manifold pressure, and (iii) output a selected intake manifold pressure setpoint based on the selection, and a multivariable control module (216) configured to (i) receive at least one target setpoint based on the selected intake manifold pressure setpoint, and (ii) control operation of an air charging system of a vehicle (100) based at least on the at least one target setpoint. [2] The control module (200) of claim 1, wherein the dynamic target selection module (220) is configured to output the selected intake manifold pressure setpoint based on a difference between the intake manifold pressure setpoint and the measured intake manifold pressure. [3] The control module (200) of claim 2, wherein the dynamic target selection module (220) is configured to output the selected intake manifold pressure setpoint further based on a comparison between (i) the difference between the intake manifold pressure setpoint and the measured intake manifold pressure and (ii) a threshold. [4] The control module (200) of claim 1, further comprising a volumetric efficiency module (224) configured to generate a total cylinder mass flow target based on the selected intake manifold pressure setpoint. [5] The control module (200) of claim 4, wherein the volumetric efficiency module (224) is configured to generate the cylinder total mass flow target further based on a volumetric efficiency calibration map. [6] A method for controlling an air charging system of a vehicle (100), the method comprising: Receiving an intake manifold pressure setpoint and a measured intake manifold pressure; Select between the intake manifold pressure setpoint and the measured intake manifold pressure; Outputting a selected intake manifold pressure setpoint based on the selection; Receiving at least one target setpoint based on the selected intake manifold pressure setpoint; and Controlling the operation of the air charging system based on the at least one target setpoint. [7] The method of claim 6, further comprising outputting the selected intake manifold pressure setpoint based on a difference between the intake manifold pressure setpoint and the measured intake manifold pressure. [8] The method of claim 7, further comprising outputting the selected intake manifold pressure setpoint further based on a comparison between (i) the difference between the intake manifold pressure setpoint and the measured intake manifold pressure and (ii) a threshold. [9] The method of claim 6, further comprising generating a total cylinder mass flow target based on the selected intake manifold pressure setpoint. [10] The method of claim 9, further comprising generating the cylinder total mass flow target further based on a volumetric efficiency calibration map.

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