Methods and systems for pressure surge control

Abstract

Methods for a turbocharged engine, comprising: Adjusting a pressure surge line of a compressor map during vehicle operation as a function of vehicle speed.

Description

Area

[0001] The present application relates to methods and systems for adjusting a calibration of pressure surge lines in engine systems configured with a continuously variable compressor return valve in order to improve pressure surge control. Background and Summary

[0002] Engine systems can be configured with pressure-boosting devices such as turbochargers or superchargers to provide a boosted air charge and improve peak power output. Using a supercharger allows a smaller-displacement engine to deliver as much power as a larger-displacement engine, but with added fuel economy benefits. However, superchargers are prone to pressure surges. For example, when a driver releases the accelerator pedal, an engine intake throttle valve closes, resulting in reduced forward airflow through the supercharger and a potential pressure surge. This pressure surge can cause NVH (noise, vibration, and harshness) problems, such as unwanted noise from the engine intake system, in addition to affecting drivability and performance.For example, during a hard pressure surge, the compressor allows air to momentarily flow back through the compressor, resulting in rapid oscillations of high amplitude, while during a soft pressure surge, smaller pressure oscillations are experienced.

[0003] US patent 2009 / 0325010A1 discloses an adaptive compressor pump control in a fuel cell system, whereby a safety margin to the surge line or the surge line itself is adapted. However, no dependency on vehicle speed or other parameters influencing the perceptibility of noise is specified.

[0004] US 2011 / 0 253 111 A1 concerns condensate management for compressed air storage systems in motor vehicles. This document discloses the discharge of condensate from a pressurized gas cylinder, whereby, due to considerations regarding the resulting noise, this only occurs at vehicle speeds above a certain threshold or similar indicators of ambient noise.

[0005] Compressor operating points that result in a hard pressure surge can be identified on a compressor map, which graphically represents the compressor pressure-to-flow rate ratio. A hard pressure surge occurs when the compressor's operating point moves to the left of a "surge line." Therefore, engine control units can target compressor operation to avoid the hard pressure surge region to the left of the surge line. Soft pressure surges are common when the constant-speed compressor lines on the compressor map have a positive slope. While a soft pressure surge is characterized by small-amplitude oscillations in pressure and flow under constant conditions, if large enough, these oscillations can also lead to audible NVH (noise, vibration, and harshness) and / or drivability issues.Another NVH issue, known as "tap-to-drive whine", typically occurs when tapping the accelerator pedal.

[0006] To address both forms of compressor pressure surges and tap-start hiss, engine systems can incorporate a compressor return valve (CRV), such as a continuously variable compressor return valve (CCRV), coupled above the compressor. An example of such a valve is shown by Narayanan et al. in patent application US 2012 / 0328410A1. The valve opening can be enlarged in response to an indication of a pressure surge, recirculating some air from the compressor outlet to the compressor inlet and rapidly reducing the boost pressure. The resulting increase in compressor flow and decrease in the compressor pressure ratio shifts the compressor's operating point away from the pressure surge line. The CCRV can also be used to avoid regions on the hiss map that produce undesirable noise levels when the accelerator pedal is tapped, by calibrating the pressure surge line differently.

[0007] The inventors have identified potential problems that can arise during pressure surge line calibration. In particular, pressure surge lines calibrated to reduce soft surges and tap-hiss can result in torque loss. For example, a pressure surge line calibrated to avoid the soft surge and / or tap-hiss region may result in a compressor operating point where insufficient turbine power is available to generate boost pressure. Therefore, this can result in torque loss. For instance, if a CCRV is opened to prevent a compressor's operating point from crossing an aggressively calibrated pressure surge line to the left, boost pressure and engine torque output may fall short of the torque requested when the accelerator pedal is tapped. This can reduce vehicle power and degrade the vehicle's drivability.

[0008] In one example, the above problem can be addressed by a method for a supercharged engine, comprising: adjusting a pressure surge curve of a compressor map during vehicle operation as a function of vehicle speed. In this way, tap-start whistling can be addressed without losing power from the supercharged engine when the accelerator pedal is tapped.

[0009] As an example, an engine system may include a compressor with a compressor return path that connects a compressor outlet (e.g., upstream or downstream of an intercooler coupled to the compressor) to a compressor outlet. The flow through the return path can be controlled by a continuously variable valve. An engine control unit can continuously adjust the valve position during steady-state and transient engine operating conditions based on changes in intake air flow to maintain a compressor flow rate at or above a pulse-limited flow rate (that is, a compressor flow rate at a pulse limit (e.g., the line of hard pulses) of the compressor).Furthermore, the control unit can continuously adjust the pressure surge curve on the compressor map based on vehicle operating conditions, including vehicle speed in addition to the compressor pressure ratio. Specifically, the pressure surge curve can be calibrated more aggressively at lower vehicle speeds, while it can be calibrated less aggressively at higher vehicle speeds. At higher vehicle speeds above a certain threshold, road and wind noise can mask the turbocharger's whistling sounds. Therefore, at higher vehicle speeds, an initial pressure surge curve with a less aggressive calibration can be used to prioritize driving dynamics over NVH reduction.At lower vehicle speeds below the threshold vehicle speed, road and wind noise may not be sufficient to mask the turbocharger's whistling noise. Therefore, at lower vehicle speeds, when driving dynamics are less of a concern, a second pressure surge line with a less aggressive calibration can be used to mitigate NVH issues. Accordingly, in response to a light touch of the accelerator pedal, which occurs at vehicle speeds below the threshold vehicle speed as well as above the threshold, the whistling noise can be reduced by adjusting the CCRV opening to operate the compressor outside (e.g., at a higher compressor flow rate) of a primary pressure surge line, which is adjusted with the more aggressive calibration.In comparison, when releasing the accelerator pedal, which occurs at vehicle speeds above the threshold and below, a release pressure surge can be reduced by adjusting the CCRV opening to operate the compressor outside (e.g., at a higher compressor flow rate) a second pressure surge line, which is adjusted with the less aggressive calibration. In one example, the compressor can operate to the right of the corresponding pressure surge line after the CCRV adjustments. In each driving cycle, the pressure surge line adjustment and the occurrence of actual pressure surges (or hissing) can be learned to update the pressure surge line calibration table. In some examples, the pressure surge line can be further adjusted based on engine speed.

[0010] In this way, a compressor pressure surge curve can be calibrated as a function of vehicle speed to utilize vehicle noise at higher speeds to mask whistling noises, while prioritizing NVH mitigation at lower speeds. As a result, it may be possible to achieve the technical outcome of a balanced compromise between drivability and NVH reduction, thereby improving customer satisfaction across a wide range of operating conditions. Brief description of the drawings Fig. Figure 1 shows an exemplary supercharged engine system that includes a compressor return valve. Fig. Figure 2 shows an example compressor map that includes the vehicle response based on the compressor return flow. Fig. Figure 3 shows an exemplary tap-to-touch performance in response to an aggressive calibration of the pressure surge line. Fig. Figure 4A shows an exemplary compressor map containing a variety of pressure surge lines calibrated with different degrees of aggressiveness. Fig. Figure 4B shows an exemplary graphical representation of the braking torque, which corresponds to the engine power at each of the pressure surge lines of Fig. 4A contains. Fig. Figure 5A shows a block diagram illustrating a first exemplary method for fitting a pressure surge line based on vehicle speed, engine speed and compressor pressure ratio according to the present disclosure. Fig. Figure 5B shows a block diagram illustrating a second exemplary method for adjusting the pressure surge line based on vehicle speed, engine speed and compressor pressure ratio according to the present disclosure. Fig. Figure 5C shows a block diagram illustrating a third exemplary method for adjusting the pressure surge line based on vehicle speed, engine speed and compressor pressure ratio according to the present disclosure. Fig. Figure 6A shows an overview flowchart illustrating an exemplary procedure for calibrating a pressure surge line and adjusting a compressor return valve based on the calibrated pressure surge line according to the present disclosure. Fig. Figure 6B shows an overview flowchart illustrating an exemplary procedure for determining a calibration type to be used during the calibration of the in Fig. The pressure surge line shown in 6A is to be applied, according to the present disclosure. Fig. Figure 7 shows an overview flowchart for adjusting the compressor return valve during temporary engine operating conditions according to the present disclosure. Fig. Figure 8 shows an exemplary sequence that includes pressure surge line matching, engine power and NVH response according to the present disclosure. Detailed description

[0011] The following description concerns systems and procedures for calibrating a pressure surge line of a compressor map (such as the one in Fig. 2 (map shown) for a compressor used in a supercharged engine system such as the system of Fig. 1 is included. For example, drivability may be reduced if the pressure surge line is aggressively calibrated to avoid compressor operation in regions of soft pressure surges to reduce noise, vibration and shock (NVH), as in the Fig. 3-4B shown. To achieve a balanced compromise between driving dynamics and NVH mitigation, a control system can be configured, a control routine like the routines of the Fig. 6A-7 to perform the pressure surge line calibration based on vehicle speed and / or engine speed in addition to the compressor pressure ratio. Furthermore, the controller can perform the calibration according to the procedures of Fig. Adjust 5A-5C to determine a final compressor pressure surge curve based on vehicle speed and / or engine speed. An example calibration of the pressure surge curve based on vehicle speed and / or engine speed is shown in Fig. 8 shown.

[0012] Fig. Figure 1 shows a schematic representation of an exemplary turbocharged engine system 100, which includes a multi-cylinder internal combustion engine 10 and two turbochargers 120 and 130. As a non-restrictive example, the engine system 100 can be included as part of a propulsion system for a passenger car. The engine system 100 can receive intake air via the intake duct 140. The intake duct 140 can contain an air filter 156. The engine system 100 can be a split-engine system, with the intake duct 140 branching downstream of the air filter 156 into a first intake duct branch and a second intake duct branch, each containing a turbocharger compressor.In the resulting configuration, at least one portion of the intake air is directed via a first intake duct branch 142 to the compressor 122 of the turbocharger 120, and at least another portion of the intake air is directed via a second intake duct branch 144 of the intake duct 140 to the compressor 132 of the turbocharger 130.

[0013] The first portion of the total intake air, compressed by the compressor 122, can be fed to the intake manifold 160 via a first parallel branched intake duct 146. In this way, intake ducts 142 and 146 form a first combined branch of the engine's air intake system. Similarly, a second portion of the total intake air can be compressed by the compressor 132 and fed to the intake manifold 160 via a second parallel branched intake duct 148. Accordingly, intake ducts 144 and 148 form a second combined branch of the engine's air intake system. As in Fig. As shown in Figure 1, the intake air from the intake ducts 146 and 148 can be recombined via a common intake duct 149 before it reaches the intake manifold 160, where the intake air can be supplied to the engine.

[0014] In some examples, the intake manifold 160 can contain an intake manifold pressure sensor 182 for estimating manifold pressure (MAP) and / or an intake manifold temperature sensor 183 for estimating manifold air temperature (MCT), each communicating with the controller 12. The common intake duct 149 can contain an intercooler 154 and an intake throttle valve 158. The position of the intake throttle valve 158 can be adjusted via a throttle actuator (not shown) that is communicatively coupled to the controller 12. A throttle intake pressure or TIP sensor 173 can be connected upstream of the intake throttle valve 158 and downstream of the intercooler 154 to the common intake duct 149. Furthermore, the TIP sensor 173 can be arranged downstream of the compressors 122 and 132. The throttle inlet pressure, also known as boost pressure or boost pressure, can be estimated by the TIP sensor 173.In one example, the TIP sensor can be used to determine compressor pressure surge conditions based on the frequency and / or amplitude of a signal from the TIP sensor. The TIP sensor can have a bandwidth greater than 100 Hertz, which may be suitable for detecting compressor pressure surges.

[0015] A compressor return channel 150 can be provided to control compressor pressure surges. To reduce compressor pressure surges, such as those that occur when the driver releases the accelerator pedal, boost pressure from the intake manifold can be released into the intake duct 140 downstream of the air cooler 154 and upstream of the intake throttle valve 158 (specifically downstream of the air filter 156 and upstream of the junction of intake ducts 142 and 144). By directing charged air from an intake throttle valve inlet upstream to the compressor inlets, the pressure surge region can be avoided.

[0016] The flow through the compressor return channel 150 can be controlled by adjusting the position of the compressor return valve 152 (CRV 152) located therein. The CRV 152 can also be referred to as a compressor pressure surge valve, a compressor bypass valve (CBV), a diverter valve, etc. In the example shown, the compressor return valve 152 can be a continuously variable valve whose position can be adjusted to a fully open position, a fully closed position, or any position in between. Consequently, the compressor return valve 152 can also be referred to herein as a continuously variable compressor return valve or CCRV. In the example shown, the CCRV 152 is configured as a throttle valve, although the CCRV may be configured differently in other embodiments (e.g., as a poppet valve). Accordingly, the CCRV 152 can be a throttle valve (e.g.,as a throttle plate) and a position sensor to communicate a change in the position of the CCRV throttle plate to control unit 12. The CCRV (or simply CRV) throttle plate position sensor may also be referred to as the throttle position sensor (TPS) or CCRV throttle position sensor. It will be acknowledged that, while the CCRV shown is for a twin-turbocharged V-6 engine in . Fig. 1 is configured, the CCRV can be applied equally in other engine configurations, such as I-3, I-4, V-8 and other engine configurations with one or more turbochargers.

[0017] In an alternative configuration, the compressor return channel can be arranged such that compressed air flows from the upstream air cooler 154 to a location upstream of compressors 122 and 132. In another configuration, two return paths can be provided, each with a return valve, each arranged such that compressed air moves from the compressor outlet to the compressor inlet. It will also be acknowledged that the methods described herein can be applied to a compressor return valve that is not continuously adjustable.

[0018] Under nominal engine operating conditions, the continuously variable compressor return valve 152 can be nominally closed or held almost closed. In such a position, the valve can be operated with known or negligible leakage. The opening of the CCRV 152 can then be increased in response to a pressure surge. In some embodiments, one or more sensors can be coupled in the compressor return channel 150 to determine the mass of the recirculated flow being conveyed from the throttle inlet to the intake manifold. The various sensors can include, for example, pressure, temperature, and / or flow sensors.

[0019] In alternative embodiments, the compressor return valve can be configured as a two-position valve, adjustable to a fully closed and a fully open position. However, boost pressure control can be improved by using a CCRV (compressor return control valve). Additionally, by coordinating the operation of the CCRV with that of a boost pressure control valve, boost pressure response and surge margins can be enhanced. Therefore, the effect of opening or closing the CCRV 152 on boost pressure can be essentially instantaneous. This allows for rapid boost pressure and surge control.

[0020] The engine 10 can contain a variety of cylinders 14. In the example shown, the engine 10 contains six cylinders arranged in a V configuration. Specifically, the six cylinders are arranged in two rows, the first row 13 and the second row 18, with each row containing three cylinders. In alternative examples, the engine 10 can contain two or more cylinders, such as 4, 5, 8, 10, or more. These various cylinders can be evenly spaced and arranged in alternative configurations such as V, inline, boxer, etc. Each cylinder 14 can be configured with a fuel injector 166. In the example shown, the fuel injector 166 is a direct injector in the cylinder. However, in other examples, the fuel injector 166 can be configured as a port-based fuel injector.

[0021] The intake air supplied to each cylinder 14 (hereinafter also referred to as combustion chamber 14) via the common intake port 149 can be used for fuel combustion, and the combustion products can then be expelled via row-specific parallel exhaust ports. In the example shown, the first cylinder bank 13 of the engine 10 can expel the combustion products via a first parallel exhaust port 17, and the second cylinder bank 18 can expel the combustion products via a second parallel exhaust port 19. Each of the first and second parallel exhaust ports 17 and 19 can furthermore contain a turbocharger turbine. Specifically, combustion products expelled via exhaust port 17 can be directed through the exhaust turbine 124 of the turbocharger 120, which in turn can provide mechanical work to the compressor 122 via shaft 126 to provide compression to the intake air.Alternatively, some or all of the exhaust gases flowing through exhaust channel 17 can bypass the exhaust turbine 124 via the turbine bypass channel 123, as controlled by the boost pressure control valve 128. Likewise, combustion products expelled through exhaust channel 19 can be routed through the exhaust turbine 134 of the turbocharger 130, which in turn can provide mechanical work to the compressor 132 via shaft 136 to compress the intake air flowing through the second branch of intake channel 144 of the engine intake system. Alternatively, some or all of the exhaust gas flowing through exhaust channel 19 can bypass the exhaust turbine 134 via the turbine bypass channel 133, as controlled by the boost pressure control valve 138.

[0022] In some examples, the exhaust gas turbines 124 and 134 can be configured as variable geometry turbines, with the controller 12 able to adjust the position of the turbine impeller blades to vary the level of energy received from the exhaust gas flow and transferred to their respective compressors. Alternatively, the exhaust gas turbines 124 and 134 can be configured as variable nozzle turbines, with the controller 12 able to adjust the turbine nozzle position to vary the level of energy received from the exhaust gas flow and transferred to their respective compressors. For example, the control system can be configured to vary the blade or nozzle position of the exhaust gas turbines 124 and 134 independently via respective actuators.

[0023] The exhaust gases in the first parallel exhaust channel 17 can be discharged into the atmosphere via the branched parallel exhaust channel 170, while the exhaust gases in the second parallel exhaust channel 19 can be discharged into the atmosphere via the branched parallel exhaust channel 180. Exhaust channels 170 and 180 can contain one or more exhaust aftertreatment devices such as a catalytic converter and one or more exhaust gas sensors (not shown).

[0024] The position of the intake and exhaust valves of each cylinder 14 can be controlled by hydraulically actuated tappets coupled to valve pushrods or by a cam-type switching mechanism using cams. In this example, at least the intake valves of each cylinder 14 can be controlled by cam actuation using a cam actuation system. Specifically, the intake valve cam actuation system 25 can include one or more cams and can utilize adjustable cam control or lift for the intake and / or exhaust valves. In alternative embodiments, the intake valves can be controlled by electric valve actuation. Likewise, the exhaust valves can be controlled by cam actuation systems or electric valve actuation.Cam actuation systems may include one or more cams mounted on one or more camshafts and may utilize one or more cam shape switching (CPS), variable cam timing (VCT), variable valve timing (VVT) and / or variable valve lift (VVL) systems that can be operated by control 12 to adjust valve operation.

[0025] The motor system 100 can be controlled at least partially by a control system 15, which includes the control unit 12, and by input from a driver of the vehicle 190 via an input device 192. In this example, the input device 192 includes an accelerator pedal and a pedal position sensor 194 for generating a proportional pedal position signal PP.

[0026] The control system 15 is configured to receive information from a variety of sensors 16 (various examples of which are described herein) and send control signals to a variety of actuators 81. For example, the sensors 16 may include the TIP sensor 173, a humidity sensor, the MAP sensor 182, and the MCT sensor 183. In some examples, a throttle inlet temperature sensor may be located upstream of the intake throttle valve 158 to estimate the throttle valve air temperature (TCT). In another example, the actuators 81 may include the CCRV 152, the fuel injector 166, the intake throttle valve 158, and the boost pressure control valves 128 and 138. Other actuators, such as a variety of auxiliary valves and throttle valves, may be coupled at various locations within the engine system 100.The controller 12 can receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or code programmed into it, corresponding to one or more routines. Exemplary control routines are described here with reference to the... Fig. 5A-5C and Fig. 6-7 described.

[0027] The motor control unit 12 can use a map like the map from Fig. Use 2 to identify whether the compressor is operating in or around a pressure surge region. In particular, map 200 shows Fig. 2. A change in the compressor pressure ratio (along the Y-axis) at different compressor flow rates (along the X-axis). The map includes contour lines 205, which represent constant compressor speed. Line 202 shows a pressure surge line. Compressor operation to the left of pressure surge line 202 results in operation in a region of harsh pressure surges 204 (hatched region). Compressor operation in the region of harsh pressure surges 204 results in unpleasant NVH and a possible deterioration in engine performance. Harsh pressure surges can occur under transient conditions when the engine's airflow demand suddenly decreases, such as when the driver releases the accelerator pedal. This condition typically requires a rapid reduction in compressor outlet pressure and / or a sufficient compressor flow rate to avoid pressure surges.If this region is expected to be entered, the compressor return valve can be opened to keep the compressor operation away from pressure surge line 202. This means the compressor's operating point can be maintained to the right of pressure surge line 202. For example, opening the compressor return valve can increase the compressor flow rate and decrease the compressor outlet pressure. As a result, the compressor's operating point can be maintained to the right of pressure surge line 202.

[0028] Soft pressure surges can occur in the soft pressure surge region 206 of the compressor map, where the compressor speed lines in this example have a positive slope. Soft pressure surges are characterized by small-amplitude oscillations of pressure and flow under otherwise constant conditions. When the amplitude and frequency of the oscillations exceed a threshold, audible NVH and drivability concerns increase. To avoid compressor operation in the soft pressure surge region, the pressure surge line can be calibrated more aggressively. Therefore, the CRV can be opened to boost flow, shifting compressor operation to the right of the pressure surge line.

[0029] A desired compressor return valve flow rate (that is, the desired return flow through the compressor return valve) required to operate the compressor to the right of the pressure surge line (that is, to operate the compressor at a higher flow rate than the pressure surge line) can be determined using the following equation: m˙crv=m˙SL−m˙thr

[0030] Here, ṁ crv the desired flow of the compressor return valve, ṁ thr is an estimated flow of the engine throttle valve and ṁ SL is the minimum compressor flow required to operate the compressor to the right of the pressure surge line. Here, ṁ SL must be defined to include adequate leeway to account for variations from part to part and / or other noise factors that may affect the compressor condition, in which hard or soft pressure surges may occur.

[0031] Furthermore, the CRV can be used to avoid a tap-hiss condition that can occur when lightly pressing the accelerator pedal. Tap-hiss is closely related to soft pressure surges and can lead to unwanted noise with increased NVH and drivability issues when lightly pressing the accelerator pedal. To avoid compressor operation in regions on the map that can cause tap-hiss, the pressure surge line can be calibrated more aggressively to open the CRV in regions prone to tap-hiss, which may include the soft pressure surge region 206. This means that the pressure surge line on the compressor map can be moved to the right. In one example, aggressive calibration of the pressure surge line might involve moving pressure surge line 202 beyond (that is, to the right of) the soft pressure surge regions. Opening the CRV can increase compressor flow.As a result, compressor operation can be shifted to the right of the aggressively calibrated pressure surge line. An example of compressor operation when the accelerator pedal is lightly depressed with the CRV closed is shown by line 208. When there is no compressor recirculation (that is, when the CRV is closed), the compressor operates in the soft surge region during the initial depressurization, causing the "tap-depressor" hiss. An example of compressor operation when the accelerator pedal is lightly depressed with the CRV open is shown by line 207. When recirculation flow is added (for example, by opening the CRV), the compressor operates to the right of the soft surge region. As a result, compressor operation is shifted away from the soft surge region, and the "tap-depressor" hiss is reduced.To mitigate conditions of hard pressure surges, soft pressure surges, and tap-hiss, for example, it may be desirable for compressor operation to remain outside both the hard pressure surge region 204 and the soft pressure surge region 206 (that is, the no-surge region 209) whenever possible, including steady and transient motor conditions. Therefore, the pressure surge line can be calibrated more aggressively. In other words, the pressure surge line can be calibrated so that it is located further to the right on the compressor map. For example, for a given compressor pressure ratio, a first compressor flow rate at a first corresponding operating point on a more aggressively calibrated pressure surge line may be greater than a second compressor flow rate at a second corresponding operating point on a less aggressively calibrated pressure surge line.However, if the pressure surge line is calibrated more aggressively, there may be insufficient turbine power to generate the desired boost, resulting in a loss of torque.

[0032] An exemplary reduction in tap-to-tap performance in response to aggressive calibration of the pressure surge line is shown in Fig. 3 shown. Specifically, it shows Fig. 3 an operating sequence 300, which represents an exemplary motor performance during a tap-on state when the pressure surge line is aggressively calibrated. Fig. Figure 3 shows the desired boost pressure on curve 302, the actual boost pressure on curve 304, the desired braking torque on curve 306, the actual braking torque on curve 308, and a CCRV opening value on curve 310. The vertical labels t0-t2 represent times of interest during the sequence. In all of the curves discussed below, the x-axis represents time, and time increases from the left side of each curve to the right side.

[0033] The first curve from the top in Fig. 3 represents boost pressure at time, where the Y-axis represents the boost pressure and the boost pressure increases in the direction of the Y-axis arrow.

[0034] The second curve from the top in Fig. 3 represents braking torque at time, where the Y-axis represents the braking torque, which increases in the direction of the Y-axis arrow.

[0035] The third curve from the top in Fig. 3 represents CCRV opening at time , with the opening of the CCRV increasing in the direction of the Y-axis arrow.

[0036] At time t1, a desired boost pressure and torque may increase in response to a tap-off event. Due to aggressive calibration of the pressure surge line, these demands can cause the compressor operating point to move to the left of the pressure surge line. To keep the compressor operating away from the region to the left of the pressure surge line, the CCRV (Coolant Control Valve) can be instructed to open (at t2). Opening the CCRV allows the compressor flow to increase. As a result, the compressor operating point may move to the right of the aggressively calibrated pressure surge line and into the region without pressure surges. However, due to the CCRV opening in response to tap-off (as a result of the aggressive pressure surge line calibration), the amount of turbine energy required to achieve the desired boost pressure increases and may exceed the available energy.As a result, the actual boost pressure and torque may not reach the desired values, leading to reduced engine power. The inventors here have recognized that the engine torque output can decrease with increasing aggressiveness of the pressure surge line calibration.

[0037] One example is the change in torque when the calibration aggressiveness of the pressure surge line is changed in the Fig. 4A and Fig. 4B is shown. Specifically, it shows Fig. 4A includes a chart 400a that shows the change in the compressor pressure ratio (along the Y-axis) at different compressor flow rates (along the X-axis). Chart 400a contains contour lines 205, representing different compressor speeds, and pressure surge lines 402, 404, and 406, each with varying degrees of aggressiveness. For example, pressure surge line 406 is calibrated more aggressively than pressure surge line 404, and pressure surge line 404 is calibrated more aggressively than pressure surge line 402.

[0038] Fig. Figure 4B shows a chart 400b indicating the change in engine braking torque (along the Y-axis) at various engine speeds based on the pressure surge line calibration. For example, curve 408 shows the change in engine braking torque with respect to engine speed when pressure surge line 402 is used, curve 410 shows the change in engine braking torque with respect to engine speed when pressure surge line 404 is used, and curve 412 shows the change in engine braking torque with respect to engine speed when pressure surge line 406 is used. As the degree of aggressiveness of the pressure surge line calibration increases, particularly during engine operation at low to medium engine speeds, the engine torque output may decrease, as shown here in the Fig. 4A and Fig. Figure 4B illustrates this. If the compressor is operating at operating point 403 and a less aggressive pressure surge line (e.g., pressure surge line 402) is used, then, for example, operating point 403 is located to the right of the less aggressive pressure surge line 402. Consequently, surge mitigation operations, such as opening the compressor return valve to move the operating point to the right of the pressure surge line, may not be necessary.

[0039] However, if a more aggressively calibrated surge line (e.g., surge line 404 or surge line 406) is used (to, for example, avoid regions of soft surges and tap-hissing conditions), the compressor operating point 403 is located to the left of surge lines 404 and 406. Therefore, it can be determined that the compressor is operating in the surge region, and consequently, the compressor return valve can be opened to increase compressor flow, thus moving the operating point to the right of surge lines 404 and 406 to mitigate surge conditions. However, opening the compressor return valve can decrease the boost pressure, and consequently, the torque output may be reduced.

[0040] The inventors here have recognized that road and wind noise can mask the turbocharger's hissing sound under vehicle operating conditions where the vehicle speed exceeds a threshold vehicle speed. Therefore, to improve engine torque output and prioritize drivability over NVH (noise, vibration, and harshness), the pressure surge line can be calibrated less aggressively under conditions of high vehicle speeds above a threshold vehicle speed. This means that the compressor pressure surge line calibration can be based on vehicle speed in such a way that a less aggressive calibration can be performed at high vehicle speeds above the threshold vehicle speed.By calibrating the pressure surge line less aggressively, it may not be necessary to open the compressor return valve to return flow through the compressor in order to operate the compressor to the right of the pressure surge line. As a result, boost pressure and torque output may meet requirements, and consequently, drivability and tap-start performance may be improved. In some examples, when using the less aggressively calibrated pressure surge line, the compressor return valve may open at vehicle speeds above the threshold vehicle speed to operate the compressor to the right of the less aggressively calibrated pressure surge line.However, the compressor return valve opening required to operate the compressor to the right of a less aggressively calibrated pressure surge line may be smaller than the compressor return valve opening required to operate the compressor to the right of a more aggressively calibrated pressure surge line. At low vehicle speeds, however, sufficient road and wind noise may not be available to mask the hissing sound. Therefore, at low vehicle speeds, the torque output may be reduced in favor of improved NHV (Non-Hyper-Variable Ratio), and a more aggressive pressure surge line calibration may be used accordingly.

[0041] Similarly, if the engine speed is higher than a threshold engine speed, the engine noise can mask the turbocharger's hissing sound. Therefore, under conditions of high engine speeds exceeding the threshold engine speed, the pressure surge line can be calibrated less aggressively. This means that the compressor pressure surge line calibration can be based on engine speed in such a way that a less aggressive calibration can be performed at high engine speeds. As a result, torque output and drivability at high engine speeds can be improved.

[0042] Furthermore, the inventors recognized that sibilance may not occur at very low engine speeds and that sibilance is observed during operation at low to medium engine speeds when the accelerator pedal is lightly pressed. As a result, if the pressure surge line is calibrated more aggressively, torque in the lower engine speed range (i.e., torque at very low engine speeds) may be unnecessarily lost. Therefore, since sibilance may not occur when the accelerator pedal is lightly pressed at very low engine speeds, a less aggressive calibration of the pressure surge line can be performed when the engine is operated at very low engine speeds to improve drivability.

[0043] However, the hissing noises can be more pronounced when lightly pressing the accelerator pedal at low to medium engine speeds. Therefore, when operating in the low to medium engine speed range, a more aggressive pressure surge line calibration can be used to reduce NVH problems that occur due to hissing conditions when lightly pressing the accelerator pedal.

[0044] Taken together, the inventors have recognized that the pressure surge line can be calibrated as a function of vehicle speed and / or engine speed in addition to the compressor pressure ratio. This means that when operating the vehicle at high vehicle speeds, high engine speeds, and very low engine speeds, a less aggressive calibration of the pressure surge line can be used. When operating the vehicle at low vehicle speeds and low to medium engine speeds, a more aggressive calibration can be used. Furthermore, the calibration of the pressure surge line can be based on the compressor pressure ratio. Details of the calibration of the pressure surge line based on vehicle speed and / or engine speed in addition to the compressor pressure ratio are described in relation to the mechanisms of the Fig. 5A-5C, Routines of Fig. 6A-7 and the example of Fig. 8 further elaborated.

[0045] The transmission of noise into the passenger compartment is highly dependent on the vehicle. In some applications, the pressure surge line may be calibrated solely based on vehicle speed. In others, it may be calibrated solely based on engine speed. In still others, it may be calibrated based on both vehicle speed and engine speed. The implemented approach will depend on the levels of various noises, such as hissing, engine noise, wind noise, etc.

[0046] In this way, drivability can be improved by calibrating the pressure surge line as a function of vehicle speed and / or engine speed, taking advantage of the fact that vehicle and engine noise mask whistling noises under conditions of high vehicle speed and engine speed. Furthermore, by prioritizing NVH reduction when vehicle and engine noise are insufficient to mask whistling noises, a balanced compromise between drivability and NVH reduction can be achieved, thereby improving customer satisfaction across a wide range of operating conditions.

[0047] The Fig. 5A, Fig. 5B and Fig. Section 5C shows block diagrams illustrating exemplary procedures for obtaining a desired final pressure surge curve based on vehicle speed, engine speed, and compressor pressure ratio. Specifically, it shows Fig. 5A a method 500a for obtaining the desired final pressure surge line by using one or more lookup tables; Fig. Figure 5B shows a method 500b for obtaining the desired pressure surge line by merging one or more pressure surge line calibrations via a lookup table; and Fig. Figure 5C shows a procedure 500c for obtaining the desired final pressure surge line by adding the outputs from two lookup tables.

[0048] Now with Fig. Continuing from section 5A, the procedure 500a may include using a first lookup table 502, which is a function of engine speed and pressure ratio. An output 503 of the first table 502 may be used as an input to a second lookup table 504, which is a function of vehicle speed. The second table 504 may receive the vehicle speed as a further input. The desired final pressure surge curve for a given pressure ratio, engine speed, and vehicle speed may be obtained as an output of the second table 504.

[0049] In some examples, the pressure ratio and vehicle speed can be used as inputs to the first table 502; and outputs of the first table and vehicle speed can be used as inputs to the second table 504.

[0050] Continuing with Fig. Method 500b may include two calibrations of the pressure surge line, comprising an aggressive calibration and a non-aggressive calibration, both based on the compressor pressure ratio. For example, a first lookup table 506 may be used to generate a basic pressure surge line (SL1) without aggressive calibration, and a second lookup table 510 may be used to generate an aggressive pressure surge line (SL2) with aggressive calibration. Subsequently, the basic pressure surge line (SL1) and the aggressive pressure surge line (SL2) may be merged as a weighted function of engine speed and vehicle speed via a lookup table to obtain the desired final pressure surge line.For example, a fusion variable α can be determined as a function of engine speed and vehicle speed, and the fusion function can be defined as SL1α + SL2(1-α). Furthermore, the value of the fusion variable can vary between 0 and 1.

[0051] In one example, the degree of aggressiveness of the final pressure surge line calibration can vary based on the value of the fusion variable α. For instance, the degree of aggressiveness can increase as the value of the fusion variable α decreases. As an example, the final pressure surge line can be calibrated more aggressively relative to the calibration when the fusion variable has a value of one, and more aggressively when the fusion variable has a value of zero.

[0052] Continuing with Fig. Method 500c can utilize a lookup table 514, which contains the engine speed and pressure ratio as inputs, and a lookup table 518, which contains the vehicle speed and pressure ratio as inputs. The output 515 of table 514 and the output 517 of table 518 can be added to obtain the final pressure surge line.

[0053] It will be acknowledged that, while the examples presented herein represent calibration of the pressure surge line based on vehicle speed and engine speed, in some examples the pressure surge line can be calibrated as a function of vehicle speed only. In some other examples, the pressure surge line can be calibrated as a function of engine speed only.

[0054] In one example, the degree of aggressiveness of the calibration required to obtain the desired final pressure surge line can be based on the pressure ratio, engine speed, and vehicle speed. Accordingly, the procedures of Fig. 5A, Fig. 5B and Fig. The 5C pressure ratio, engine speed, and vehicle speed are used to determine the degree of calibration aggressiveness required to obtain the desired final pressure surge line. For example, at higher vehicle speeds (above a threshold vehicle speed) and / or engine speeds (above a first threshold engine speed), a less aggressive calibration can be implemented to obtain the final pressure surge line. Similarly, at very low engine speeds (below a second threshold engine speed), a less aggressive calibration can be implemented to obtain the final pressure surge line.However, at low vehicle speeds below the threshold vehicle speed and at engine speeds between the first and second threshold engine speeds, a more aggressive calibration can be implemented to obtain the final pressure surge line. Details on determining the type of calibration (more aggressive or less aggressive) to obtain the final pressure surge line based on vehicle speed and / or engine speed are further described in the [reference to be added]. Fig. 6A and Fig. 6B worked out.

[0055] In one example, the procedure of Fig. 5A-5C provides a method for a supercharged engine, comprising: adapting a pressure surge line of a compressor map during vehicle operation as a function of the vehicle speed; wherein the pressure surge line is further adapted as a function of the engine speed and the compressor pressure ratio. The method further comprises that the adaptation includes adjusting the pressure surge line with a more aggressive calibration at a vehicle speed below a threshold vehicle speed and adjusting the pressure surge line with a less aggressive calibration at a vehicle speed above the threshold vehicle speed; and that the adaptation of the pressure surge line is learned over one or more vehicle driving cycles. Furthermore, the method includes that the adaptation of the pressure surge line includes adjusting limits for each of a hard surge region and a soft surge region of the compressor map.

[0056] The method further includes the fitting process of using a first table and a second table sequentially, wherein two values ​​of the engine speed, pressure ratio and vehicle speed are entered into the first table, and one output of the first table with a remaining value of the engine speed, pressure ratio and vehicle speed is entered into the second table, and wherein one output of the second table is used to fit the pressure surge line.

[0057] The procedure further includes the fitting of determining a first, more aggressive pressure surge line calibration as a function of the compressor pressure ratio, determining a second, less aggressive pressure surge line calibration as a function of the compressor pressure ratio; and merging the first and second pressure surge line calibrations as a weighted function of vehicle speed and engine speed.

[0058] Furthermore, the procedure, which includes the fitting, includes determining a final pressure surge line based on a sum of a first output of a first table and a second output of a second table; and wherein the first table is obtained as a function of engine speed and compressor pressure ratio, and the second table is obtained as a function of vehicle speed and compressor pressure ratio.

[0059] The method may further include adjusting the opening of a continuously variable compressor return valve during vehicle operation to maintain compressor operation at a higher compressor flow rate than a compressor flow rate of the adapted pressure surge line; wherein the adjustment includes estimating a desired throttle mass flow based on engine operating conditions; estimating a threshold compressor flow rate based on the adapted pressure surge line; and adjusting the opening of the CCRV based on a difference between the desired throttle mass flow and the threshold flow rate.

[0060] The procedure further includes adjusting the pressure surge line as a function of vehicle speed, adapting the pressure surge line with a more aggressive calibration during a tap of the accelerator pedal, which occurs at the lower vehicle speed below a threshold vehicle speed, to a higher vehicle speed above the threshold vehicle speed, and adapting the pressure surge line with a less aggressive calibration during a release of the accelerator pedal from the higher vehicle speed to the lower vehicle speed.

[0061] In another example, a procedure for a supercharged engine may involve adjusting a pressure surge line of a compressor map during vehicle operation as a function of vehicle speed only.

[0062] In yet another example, a procedure for a supercharged engine may involve adapting a pressure surge line of a compressor map during vehicle operation as a function of both the vehicle speed and the engine speed.

[0063] Now with Fig. Continuing from section 6A, an exemplary method 600 for adjusting the opening of a compressor return valve (e.g., return valve 152 in) is described. Fig. 1) shown based on a calibrated pressure surge line. The method of Fig. 6 can be found in the system of Fig. 1. executable instructions stored in non-volatile memory.

[0064] Procedure 600, described in section 602, involves estimating and / or measuring engine operating conditions. These estimated conditions may include, for example, engine speed (Ne), vehicle speed (Vs), torque demand, boost pressure, MAP, MAF, engine temperature, air-fuel ratio (AFR), exhaust catalyst temperature, ambient conditions, etc.

[0065] In 604, procedure 600 includes adjusting the compressor pressure surge curve based on each of the vehicle speed, engine speed, and compressor pressure ratio. Specifically, the pressure surge curve can be adjusted based on the vehicle speed, engine speed, and compressor pressure ratio. Details on adjusting the pressure surge curve are in Fig. 5A, Fig. 5B and Fig. 5C provided. Another procedure is provided with reference to Fig. 6B further elaborated.

[0066] After fitting the pressure surge line, procedure 600 can proceed to 606. In 606, procedure 600 includes estimating the throttle mass flow based on the operating conditions. For example, the throttle mass flow can be estimated based on a sensor output (e.g., MAP sensor output) or from the desired throttle mass flow. Furthermore, in 606, procedure 600 can include estimating a desired compressor flow rate (or threshold flow rate) based on the throttle mass flow rate and a compressor pressure surge limit. The desired compressor flow rate (or threshold flow rate) can be a pressure surge-limited compressor flow rate based on a compressor pressure surge limit and taking into account noise factors such as part-to-part variations that can affect the compressor state, where hard or soft pressure surges occur.

[0067] Next, Procedure 600 at 608 involves adjusting the compressor return valve opening based on the throttle mass flow rate to provide the desired compressor flow rate, which operates the compressor to the right of the pressure surge line. It will be recognized that estimating the throttle mass flow and the desired compressor flow rate can be performed under all engine operating conditions, including steady and transient conditions. By continuously estimating the throttle mass flow and adjusting a compressor return flow to maintain the compressor flow rate at or above the desired compressor flow rate, the compressor state can be kept outside (specifically to the right) of a region of hard pressure surges and a region of soft pressure surges.

[0068] In one example, the controller can estimate the throttle mass flow rate based on the manifold pressure sensor or the desired throttle flow rate and calculate the surge-limited compressor flow rate based on the compressor's surge limit (hard surge limit). The controller can then determine a desired compressor return flow rate (that is, a net return flow rate through the compressor via any combination of the first and second return paths) based on the difference between the surge-limited compressor flow rate and the throttle mass flow rate.

[0069] Fig. Figure 6B shows an exemplary procedure for fitting a compressor pressure surge line (e.g., a pressure surge line 202 in Fig. 2) based on vehicle speed and / or engine speed. Adjusting the compressor pressure surge line may involve determining a level of aggressiveness (also referred to herein as degree of aggressiveness) based on vehicle speed and / or engine speed. For example, the pressure surge line may be more or less aggressive based on vehicle speed and / or engine speed conditions. Implementing the less aggressive calibration may prioritize drivability over NVH. Implementing the more aggressive calibration may prioritize NVH reduction. The procedure of Fig. 6B can be used in the system of Fig. 1. executable instructions stored in non-volatile memory.

[0070] Procedure 600, as described in 612, involves estimating and / or measuring engine operating conditions. These estimated conditions may include, for example, engine speed (Ns), vehicle speed (Vs), torque demand, boost pressure, MAP, MAF, engine temperature, air-fuel ratio (AFR), exhaust catalyst temperature, ambient conditions (e.g., BP), etc.

[0071] Next, procedure 600 at 614 includes determining whether a vehicle speed is higher than a threshold vehicle speed. If the answer is yes, procedure 600 can proceed to 620. At 620, procedure 600 may include applying a less aggressive calibration to adjust the pressure surge line. For example, at higher vehicle speeds (e.g., vehicle speed higher than the threshold vehicle speed), road and wind noise may mask the turbocharger's whine. Therefore, a less aggressive calibration may be used to prioritize drivability over NVH. A less aggressive calibration may involve adjusting the pressure surge line to the left of a basic pressure surge line on the compressor map.This means that a delta adjustment can be made to the basic pressure surge line, shifting the entire surge line to the left of the compressor map. This results in a reduction of the area to the left of the adjusted surge line compared to the area to the left of the basic surge line. In one example, the basic surge line might be a manufacturer-calibrated surge line based on component performance data. In other examples, the basic surge line might be a surge line calibrated at the threshold vehicle speed.

[0072] Furthermore, in one example, the delta adjustment can be a calibratable constant. In another example, the delta adjustment can be based on a difference between a current vehicle speed and the threshold vehicle speed, with the delta adjustment increasing as the difference grows. While the example discussed here shows the delta adjustment based on vehicle speed when the vehicle speed is greater than the threshold, in some examples the delta adjustment can be based on both vehicle speed and engine speed.

[0073] Returning to 614, procedure 600 can proceed to 616 if it is determined that the vehicle speed is lower than the threshold speed. At 616, procedure 600 includes determining whether an engine speed is higher than a first threshold engine speed. If the answer at 616 is yes, procedure 600 can proceed to 620. At 620, the less aggressive calibration can be applied to adjust the pressure surge line. For example, at higher engine speeds (e.g., engine speeds higher than the first threshold), engine noise may mask the turbocharger whine. Therefore, the less aggressive calibration can be used to prioritize drivability over NVH. A less aggressive calibration may include applying the delta adjustment to adjust the pressure surge line to the left of a basic pressure surge line on the compressor map.As discussed above, in one example the basic pressure surge line may be a pressure surge line calibrated by the manufacturer. In another example, the basic pressure surge line may be a pressure surge line calibrated at the threshold engine speed.

[0074] Furthermore, the delta adjustment in an example can be a calibratable constant. In some examples, the delta adjustment can be based on a difference between a current engine speed and the first threshold engine speed, with the delta adjustment increasing as the difference grows. While the example discussed here shows the delta adjustment based on engine speed when the engine speed is higher than the first threshold, in some examples the delta adjustment can be based on both vehicle speed and engine speed.

[0075] Returning to 616, procedure 600 can proceed to 618 if it is determined that the engine speed is lower than the first threshold. At 618, procedure 600 includes determining whether the engine speed is lower than a second threshold speed. The second threshold engine speed can be lower than the first threshold engine speed. If the answer at 618 is yes, procedure 600 can proceed to 620. At 620, the less aggressive calibration can be applied to adjust the pressure surge line. For example, the noise associated with the compressor pressure surge at very low engine speeds (e.g., engine speeds lower than the second threshold) may not contribute significantly to NVH. Therefore, the less aggressive calibration can be used to prioritize drivability over NVH.A less aggressive calibration may involve applying the delta adjustment to adjust the pressure surge line to the left of a basic pressure surge line on the compressor map. As discussed above, in one example, the basic pressure surge line might be a manufacturer-calibrated surge line. In another example, the basic pressure surge line might be a surge line calibrated at the second threshold engine speed.

[0076] Furthermore, the delta adjustment in one example can be a calibratable constant. In some examples, the delta adjustment can be based on a difference between the second threshold engine speed and a current engine speed, with the delta adjustment increasing as the difference grows. While the example discussed here shows the delta adjustment based on engine speed when the engine speed is lower than the second threshold, in some examples the delta adjustment can be based on both vehicle speed and engine speed.

[0077] Returning to 618, procedure 600 can proceed to 622 if it is determined that the engine speed is higher than the second threshold and lower than the first threshold. At 622, procedure 600 includes applying a more aggressive pressure surge line calibration. At low to medium engine speeds (e.g., engine speeds between the first and second threshold engine speeds) and at very low vehicle speeds (e.g., vehicle speeds below the threshold vehicle speed), the vehicle and / or engine noise may not be sufficient to mask the turbocharger whine. Therefore, at low to medium engine speeds and low vehicle speeds, the more aggressive pressure surge line calibration can be applied to mitigate NVH problems that may arise under transient conditions (such as lightly tapping the accelerator pedal).A more aggressive calibration of the pressure surge line may involve applying the delta adjustment to move the pressure surge line to the right of a basic pressure surge line on the compressor map. In one example, the basic pressure surge line might be one calibrated at the threshold vehicle speed. In another example, the basic pressure surge line might be one calibrated at the first threshold engine speed. In yet another example, the basic pressure surge line might be one calibrated at the second threshold engine speed.

[0078] Furthermore, the delta adjustment can be a calibratable constant in one example. In some examples, the delta adjustment can be based on the vehicle speed and the engine speed.

[0079] After calibrating the pressure surge line based on the vehicle speed and / or engine speed, procedure 600 can be continued to step 606 in Fig. Return to 6A.

[0080] In some examples, a varying degree of aggressiveness, including a most aggressive calibration, a least aggressive calibration, and one or more intermediate levels of aggressiveness, can be implemented based on vehicle speed and engine speed conditions. For example, the degree of aggressiveness of the calibration can increase as the vehicle speed decreases below a threshold vehicle speed, and the degree of aggressiveness can decrease as the vehicle speed increases above the threshold vehicle speed.Furthermore, the degree of aggressiveness of the calibration may increase when the engine speed decreases in the engine speed range between the first threshold engine speed and the second threshold, and the degree of aggressiveness may decrease with an increase in engine speed above the first threshold engine speed and with a decrease in engine speed below the second threshold engine speed.

[0081] In this way, by using a less aggressive calibration of the pressure surge line under conditions of high vehicle speed, high engine speed, and / or very low engine speed, lost torque can be recovered and, consequently, drivability improved. Furthermore, NVH problems can be mitigated by using a more aggressive calibration under conditions of low vehicle speed and low to medium engine speed.

[0082] Fig. Figure 7 shows a flowchart illustrating an exemplary procedure 700 for adjusting the opening of a compressor return valve in response to a tap-off condition based on the use of a less aggressively calibrated pressure surge line or a more aggressively calibrated pressure surge line, the use being based on vehicle speed and / or engine speed. The procedure of Fig. 7 can be found in the system of Fig. 1. executable instructions stored in non-volatile memory.

[0083] Procedure 700, as described in section 702, involves estimating and / or measuring engine operating conditions. These estimated conditions may include, for example, engine speed, vehicle speed, torque demand, boost pressure, MAP, MAF, engine temperature, air-fuel ratio (AFR), exhaust catalyst temperature, ambient conditions (e.g., BP), etc.

[0084] Procedure 700 at 704 then determines whether one or more speed / RPM conditions are met. These conditions may include the vehicle speed being higher than a threshold vehicle speed, the engine speed being higher than a first threshold RPM, and the engine speed being lower than a second threshold RPM. If at least one of the speed / RPM conditions is met, the answer at 704 is YES, and Procedure 700 continues at 706. If none of the speed / RPM conditions are met, the answer at 704 is NO, and Procedure 700 continues at 708.

[0085] In procedure 706, method 700 includes the use of a first pressure surge line that has been calibrated less aggressively. This means that the first pressure surge line can be used to determine the minimum compressor flow required to keep the compressor operating point to the right of the first pressure surge line.

[0086] By utilizing the first, less aggressively calibrated pressure surge line at high vehicle speed and / or high engine speed, drivability can be prioritized over NVH reduction, as the noise associated with high engine speed and / or high vehicle speed can mask NVH problems (such as a sizzle when lightly pressing the accelerator pedal). Furthermore, a less aggressively calibrated pressure surge line at very low engine speeds can be used to prioritize drivability when NVH problems are below a certain threshold. For example, when using the first, less aggressively calibrated pressure surge line, it may not be necessary to use the compressor return valve to recirculate flow through the compressor to operate the compressor to the right of the first pressure surge line.In some examples, a small amount of compressor return valve opening can be used to shift the compressor operating point to the right of the first pressure surge line (less aggressively calibrated), which may be smaller than the amount of compressor return valve opening required to shift the compressor operating point to the right of the more aggressively calibrated pressure surge line (i.e., the second pressure surge line). Consequently, for a given operating point, the torque loss when using the less aggressively calibrated pressure surge line may be smaller than the torque loss when using the more aggressively calibrated pressure surge line.

[0087] In procedure 708, method 700 incorporates a second pressure surge line that has been calibrated more aggressively. This means the second pressure surge line can be used to determine the minimum compressor flow required to keep the compressor operating point to the right of the second pressure surge line.

[0088] By utilizing the second, more aggressively calibrated pressure surge line, NVH reduction can be prioritized over drivability, as noises associated with low engine speeds and / or low vehicle speeds may not be sufficient to mask NVH resulting from tap-hiss conditions. Therefore, a more aggressive calibration can be used to shift the compressor operating point away from the pressure surge region and into the region without pressure surges, thus reducing tap-hiss conditions. For example, when using the second, more aggressively calibrated pressure surge line, the compressor return valve can be used to recirculate flow through the compressor, allowing the compressor to operate to the right of the more aggressively calibrated pressure surge line.Consequently, the required boost pressure may not be reached due to the increased compressor flow, and as a result, the torque output may be reduced. However, by utilizing a more aggressively calibrated pressure surge curve, the compressor operation can be shifted away from the pressure surge region (for example, by increasing the compressor flow). As a result, the pinging noise may be reduced.

[0089] Returning to 706, after implementing the first (less aggressively calibrated) pressure surge line, procedure 700 continues to 710. At 710, procedure 700 includes determining whether a tap-on condition is initiated. A tap-on condition can be determined based on one or more changes in pedal position, an increase in torque demand, etc. After confirming the tap-on condition, procedure 700 can continue to 714. At 714, procedure 700 can include adjusting the compressor return valve opening amount to operate the compressor to the right of the first pressure surge line, which is less aggressively calibrated. In other words, the compressor return valve can be adjusted to operate the compressor at a higher flow rate than the first pressure surge line. In an example, the opening amount can be zero.In another example, the opening amount may be smaller than an opening amount to operate the compressor to the right of the second pressure surge line (that is, to operate the compressor at a higher flow rate than the second pressure surge line), which has been calibrated more aggressively.

[0090] Returning to step 708, after implementing the second (more aggressively calibrated) pressure surge line, procedure 700 continues to step 712. At step 712, procedure 700 includes determining whether a tap-on condition is initiated. A tap-on condition can be determined based on one or more changes in pedal position, an increase in torque demand, etc. After confirmation of the tap-on condition, procedure 700 can continue to step 716.

[0091] In the case of 716, the procedure 700 may include adjusting the opening of the compressor return valve to operate the compressor to the right of the second pressure surge line, which is more aggressively calibrated. In other words, the compressor return valve may be adjusted to operate the compressor at a higher flow rate than the second pressure surge line. As discussed above, for a given engine operating condition, the amount of compressor return valve opening used to move the compressor operating point to the right of the less aggressively calibrated pressure surge line may be smaller than the amount of compressor return valve opening used to move the compressor operating point to the right of the more aggressively calibrated pressure surge line.

[0092] While the example herein illustrates the adjustment of the compressor feedback valve in response to a tap, in one example, the compressor feedback valve may be adjusted in response to the detection of accelerator pedal release at vehicle speeds higher than the threshold to operate the compressor to the right of the less aggressively calibrated pressure surge line (that is, at a higher compressor flow rate than this), and in response to accelerator pedal release at vehicle speeds below the threshold, the compressor feedback valve may be adjusted to operate the compressor to the right of the more aggressively calibrated pressure surge line (that is, at a higher compressor flow rate than this).

[0093] In this way, the compressor return valve can be adjusted based on the type of pressure surge line used (less aggressively calibrated or more aggressively calibrated), with the type of pressure surge line used being based on the vehicle speed and / or engine speed in addition to the compressor pressure ratio.

[0094] In one example, the procedure of Fig. 7. A method for a supercharged engine comprising: in response to a tap at a higher vehicle speed above a threshold vehicle speed, adjusting the position of a CCRV to operate a compressor to the right of a first pressure surge line; and in response to a tap at a lower vehicle speed below the threshold vehicle speed, adjusting the position of the CCRV to operate the engine compressor to the right of a second pressure surge line; wherein, for a given compressor pressure ratio, a first compressor operating point on the second pressure surge line has a higher compressor flow rate relative to a second compressor operating point on the first pressure surge line.

[0095] In another example, the procedure of Fig. 7. A method for a supercharged engine comprising: in response to a tap at a higher vehicle speed above a threshold vehicle speed, adjusting the position of a CCRV to operate a compressor at a first higher compressor flow rate than a first pressure surge line; and in response to a tap at a lower vehicle speed below the threshold vehicle speed, adjusting the position of the CCRV to operate the engine compressor at a second higher compressor flow rate than a second pressure surge line.

[0096] The procedure may further include calibrating the first pressure surge line less aggressively relative to the vehicle speed and calibrating the second pressure surge line more aggressively relative to the vehicle speed.

[0097] The procedure may further include increasing the CCRV opening by a first, smaller amount in response to tapping at higher vehicle speeds; and increasing the CCRV opening by a second, larger amount in response to tapping at lower vehicle speeds.

[0098] The procedure may further include adjusting the position of a CCRV in response to a release at the higher vehicle speed, operating a compressor to the right of the first pressure surge line, and adjusting the position of the CCRV in response to a release at the lower vehicle speed, operating the compressor to the right of the second pressure surge line.

[0099] In another example, the procedure may further include adjusting the position of a CCRV in response to a release at the higher vehicle speed, operating a compressor at a third higher compressor flow rate than the first pressure surge line, and adjusting the position of the CCRV in response to a release at a lower vehicle speed, operating the compressor at a fourth higher compressor flow rate than the second pressure surge line.

[0100] In some examples, adjusting the pressure surge line in response to a tap from a lower vehicle speed below the threshold vehicle speed to a higher vehicle speed above the threshold vehicle speed may involve transitioning from a more aggressively calibrated pressure surge line at the lower vehicle speed to a less aggressively calibrated pressure surge line at the higher vehicle speed. Furthermore, in response to a release from the higher vehicle speed to the lower vehicle speed, the transition may involve transitioning from the less aggressively calibrated pressure surge line at the higher vehicle speed to the more aggressively calibrated pressure surge line at the lower vehicle speed, with the more aggressively calibrated pressure surge line being delayed relative to the less aggressively calibrated pressure surge line.In other words, the more aggressively calibrated pressure surge line is located to the right of the less aggressively calibrated pressure surge line on the compressor map. For example, for any given compressor pressure ratio on the compressor map, a corresponding compressor flow rate on the more aggressively calibrated pressure surge line is higher than a corresponding compressor pressure ratio (for the given compressor pressure ratio) on the less aggressively calibrated pressure surge line.

[0101] Fig. Figure 8 shows the operating sequence 800, which represents an exemplary adjustment of the pressure surge line as a function of vehicle speed and engine speed. Fig. Figure 8 shows, by way of example, the pedal position in curve 802, the vehicle speed in curve 804, the engine speed in curve 806, the boost pressure in curve 808, the actual engine torque in curve 810, the desired engine torque in curve 809, the position of the compressor return valve (CCRV) at 812, the NVH with a less aggressive pressure pulse line calibration in curve 813, the NVH with a more aggressive pressure pulse line calibration in curve 814, and one type of pressure pulse line calibration in curve 816. The sequence of events in Fig. 8 can be done by executing instructions in the system of Fig. 1-2 according to the procedure of Fig. Figures 6A-6B are provided. The vertical markers at times t0-t5 represent times of interest during the sequence. In all of the curves discussed below, the x-axis represents time, and time increases from the left side of each curve to the right side.

[0102] The first graphic representation from above in Fig. Figure 8 represents the accelerator pedal position against time. The Y-axis represents the accelerator pedal position, and pressing the accelerator pedal increases the position in the direction of the Y-axis arrow.

[0103] The second curve from the top in Fig. Figure 8 represents vehicle speed versus time. The Y-axis represents vehicle speed, and vehicle speed increases in the direction of the Y-axis arrow. The horizontal line 803 represents a threshold vehicle speed. The threshold vehicle speed can be based on one or more variations from part to part of the vehicle system and environmental conditions.

[0104] The third curve from the top in Fig. Figure 8 represents the motor speed versus time. The Y-axis represents the motor speed, and the motor speed increases in the direction of the Y-axis arrow. The horizontal line 805 represents a first threshold motor speed. The horizontal line 803 represents a second threshold motor speed. The first and second threshold motor speeds may be based on variations from part to part of the motor system.

[0105] The fourth curve from the top in Fig. Figure 8 represents boost pressure versus time. The Y-axis represents boost pressure, and boost pressure increases in the direction of the Y-axis arrow. The horizontal line 809 represents a desired boost pressure.

[0106] The fifth curve from the top in Fig. Figure 8 represents the motor torque versus time. The Y-axis represents the motor torque, and the motor torque increases in the direction of the Y-axis arrow.

[0107] The sixth curve from the top in Fig. Figure 8 represents the position of the compressor return valve over time. The Y-axis represents the position of the compressor return valve, and the valve opening amount increases in the direction of the Y-axis arrow.

[0108] The seventh curve from the top in Fig. 8 represents the NVH value against time. The y-axis represents the NVH value, and the NVH value increases in the direction of the y-axis arrow.

[0109] The eighth curve from the top in Fig. Figure 8 represents the fusion variable α (for determining the degree of aggressiveness of the pressure surge line calibration) against time. The Y-axis represents the fusion variable α, and a value of the fusion variable α increases in the direction of the Y-axis arrow. Accordingly, the degree of aggressiveness decreases in the direction of the Y-axis arrow. Details on determining the pressure surge line calibration using the fusion variable are given herein with reference to Fig. 5B worked out.

[0110] Between t0 and t1, the vehicle may operate above the threshold vehicle speed (803) and above the first threshold engine speed (805). Consequently, vehicle noise and road noise due to high vehicle speeds, and engine noise due to high engine speed, may mask the turbocharger whine, which can occur during transient events such as a tap initiated at high vehicle speeds and / or high engine speeds. Therefore, the pressure surge line may be calibrated less aggressively (816) to prioritize drivability over NVH mitigation. As a result of the less aggressive pressure surge line calibration, the compressor may operate to the right of the less aggressively calibrated pressure surge line. Consequently, the CCRV may be closed, a desired boost pressure may be maintained, and a desired engine torque may be available.

[0111] Immediately before t1, a driver can depress the accelerator pedal, initiating a tap-start event. During the tap, a tap-start hiss may be generated (represented as an increase in NVH (814) at t1). However, due to vehicle and road noise at high vehicle speed and engine noise at high engine speed at the time of the tap, the tap-start hiss is masked. Furthermore, the compressor can continue to operate to the right of the less aggressively calibrated pressure surge line. As a result, the CCRV can remain closed, and the desired boost pressure and engine torque can be available. Consequently, drivability may be improved.

[0112] At time t1 and between t1 and t2, the engine speed and vehicle speed can increase (in response to the tap). Furthermore, the vehicle speed can remain above the threshold vehicle speed, and the engine speed can remain above the first threshold engine speed. Consequently, the less aggressively calibrated pressure surge line can be used. In some examples, the pressure surge line can be calibrated such that the degree of aggressiveness of the calibration decreases as the vehicle speed and / or engine speed increase above the threshold speed or threshold engine speed, respectively. Furthermore, the compressor can continue to operate to the right of the less aggressively calibrated pressure surge line. As a result, the CCRV can remain closed, allowing the boost pressure to increase to the desired level. Consequently, the desired torque can be provided.In this way, by using a less aggressive calibration of the pressure surge line at high engine speed and high vehicle speed, priority can be given to driving behavior (improved torque output) over NVH mitigation, since the turbo hissing noise that can occur when tapping the accelerator can be masked by external noises such as road, vehicle and / or engine noises.

[0113] Immediately before t2, the driver can initiate a release event by releasing the accelerator pedal. In response to this release, the engine speed at time t2 and between t2 and t3 may drop below the first threshold while remaining above the second threshold. This means the engine may operate in the low to mid-range RPM. Furthermore, the vehicle speed may drop below the threshold vehicle speed. In this low to mid-range operating range, the turbo whine may increase, leading to heightened NVH (noise, vibration, and harshness) issues. Therefore, the pressure surge line may need to be calibrated more aggressively to mitigate NVH problems that can arise from turbo whine (for example, during turbo tapping), as vehicle, road, and / or engine noise may not be sufficient to mask the turbo whine.Therefore, the merging variable can be used to facilitate the transition when switching from a less aggressive to a more aggressive calibration (and vice versa), thereby avoiding abrupt transitions between different levels of aggressiveness in the surge line calibrations. By calibrating the surge line more aggressively, compressor operation can be avoided in regions where the turbo whine may exceed a threshold (e.g., regions of soft surges). For example, when using the more aggressively calibrated surge line, the CCRV can be opened to prevent compressor operation to the left of the surge line.A desired CCRV flow (that is, the desired return flow through the compressor return valve) required to operate the compressor to the right of the pressure surge line can be determined based on an estimated engine throttle flow and a minimum compressor flow required to operate the compressor to the right of the pressure surge line. As a result of opening the CCRV, the compressor flow may increase and the compressor outlet pressure may decrease, thus moving the compressor operating point to the right of the more aggressively calibrated pressure surge line on the compressor map. Opening the CCRV may decrease the boost pressure and may result in a torque output (810) that is lower than desired (809).In this way, when operating under low and medium engine speed conditions and low vehicle speed conditions, priority can be given to NVH mitigation over driving behavior by calibrating the pressure surge line more aggressively.

[0114] A second tap can be initiated immediately before t3. In response to the second tap, the vehicle speed at time t3 and between t3 and t4 may exceed the threshold, and the engine speed may exceed the first threshold. Therefore, the less aggressive calibration can be used to calibrate the pressure surge line, which may allow the compressor to operate to the right of the less aggressively calibrated pressure surge line without opening the CCRV. In some examples, the CCRV may open to a small amount, which may be less than the CCRV opening amount when using the more aggressive calibration. As a result, tap performance and drivability may be improved.

[0115] Immediately before t24, the driver can release the accelerator pedal, initiating a second release event. In response to this second release, the engine speed can decrease below the second threshold at t4 and between t4 and t5. This means the engine can operate at very low speeds. Furthermore, the vehicle speed can also decrease below the threshold. At very low engine speeds (below the second threshold), NVH issues resulting from tap-start whistling can be reduced. Consequently, drivability can be prioritized over NVH mitigation. Therefore, the pressure surge line can be calibrated less aggressively. Additionally, the supercharger can operate to the right of the less aggressively calibrated pressure surge line. Therefore, the CCRV does not need to open. As a result, the desired torque can be available, and drivability at very low engine speeds can be improved.

[0116] Immediately before t5, a third tap can be initiated by the driver. In response to the tap at and after t5, the engine speed may increase above the second threshold but may remain below the first. Furthermore, the vehicle speed may increase but may remain below the threshold. During engine operation in the lower to mid-range engine speeds and at vehicle speeds below the threshold speed, the possibility of tap-whistle conditions may be high, and the engine and / or vehicle noise may not be sufficient to mask the NVH problems resulting from tap-whistle conditions. Therefore, the pressure surge line may need to be calibrated more aggressively to mitigate the NVH problems.

[0117] By calibrating the pressure surge curve not only as a function of the compressor pressure ratio but also as a function of vehicle speed and / or engine speed, additional flexibility can be achieved in defining the trade-off between drivability and NVH mitigation. As a result, customer satisfaction can be achieved across a wide range of operating conditions.

[0118] In one example, the sequence of Fig. 8. A vehicle system comprising: an engine; a compressor for supplying a supercharged air charge to the engine; a compressor return valve positioned in a passage coupling an outlet of the compressor to an inlet of the compressor, the position of the valve being continuously adjustable between a fully open and a fully closed position; a speed sensor for estimating a vehicle speed; and a controller with computer-readable instructions stored in non-volatile memory for: during vehicle operation, continuously adjusting a pressure surge line of a standard compressor card with a calibration factor based on one or both of engine speed and vehicle speed;and adjusting the opening of the compressor return valve based on inlet air flow to maintain compressor operation to the right of a pressure surge limit of the adjusted pressure surge line; wherein the standard compressor map pressure surge line is a compressor map pressure surge line provided by the vehicle manufacturer, determined based on factory-new vehicle conditions.

[0119] In another example, the sequence of Fig.8. A vehicle system comprising: an engine; a compressor for supplying a supercharged air charge to the engine; a compressor return valve positioned in a passage coupling an outlet of the compressor to an inlet of the compressor, the position of the valve being continuously adjustable between a fully open and a fully closed position; a speed sensor for estimating a vehicle speed; and a controller with computer-readable instructions stored in non-volatile memory for: during vehicle operation, continuously adjusting a pressure surge line of a standard compressor card with a calibration factor based on one or both of engine speed and vehicle speed;and adjusting the opening of the compressor return valve based on inlet air flow to maintain compressor operation at a higher flow rate than a pressure surge limit of the adjusted pressure surge line; wherein the standard compressor map pressure surge line is a compressor map pressure surge line provided by the vehicle manufacturer, determined based on factory-new vehicle conditions; and wherein adjusting the pressure surge line includes calibrating the pressure surge line less aggressively at a higher vehicle speed, which is higher than a threshold vehicle speed, and calibrating the pressure surge line more aggressively at a lower vehicle speed, which is lower than the threshold.

[0120] The system further includes instructions for the control unit to calibrate the pressure surge line less aggressively at an engine speed higher than a first threshold engine speed, to calibrate the pressure surge line less aggressively at an engine speed lower than a second threshold engine speed, and to calibrate the pressure surge line more aggressively at an engine speed lower than the first threshold and higher than the second threshold.

[0121] The system further includes the provision that the degree of aggressiveness of the calibration factor increases as the vehicle speed decreases below a threshold vehicle speed, and that the degree of aggressiveness decreases as the vehicle speed increases above the threshold vehicle speed.

[0122] It should be noted that the exemplary control and estimation routines contained herein can be used with various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and can be executed by the control system, which includes the controller in combination with various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Various actions, operations, and / or functions shown can be executed as such in the sequence shown, in parallel, or, in some cases, omitted.Likewise, the processing sequence is not necessarily required to achieve the features and benefits of the exemplary embodiments described herein, but is provided for the sake of simplicity. One or more of the actions, operations, and / or functions described may be performed repeatedly, depending on the specific strategy employed. Furthermore, the described actions, operations, and / or functions may graphically represent code to be programmed into the non-volatile memory of the computer-readable storage medium in the engine control system, with the described actions being executed by carrying out the instructions in a system that includes the various components of the engine hardware in combination with the electronic control unit.

[0123] It will be acknowledged that the configurations and routines disclosed herein are exemplary in nature and that these specific embodiments are not to be considered in a limiting sense, since numerous modifications are possible. For example, the foregoing technology can be applied to engine types V-6, I-3, I-4, I-6, V-12, Opposite 4, and others. The subject matter of this disclosure includes all new and non-obvious combinations and partial combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0124] The following patent claims disclose certain combinations and partial combinations that are considered novel and not obvious. These claims may refer to "one" element or "a first" element, or the equivalent thereof. Such claims are to be understood as including the incorporation of one or more such elements and neither requiring nor excluding two or more such elements. Other combinations and partial combinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by presenting new claims in this or a related application. Such claims, whether broader in scope than, narrower than, the same as, or different from the original claims, are also considered to be included in the subject matter of the present disclosure.

Claims

[1] Method for a turbocharged engine, comprising: Adjusting a pressure surge line of a compressor map during vehicle operation as a function of vehicle speed. [2] Method according to claim 1, wherein the pressure surge line is further adapted as a function of the motor speed and the compressor pressure ratio. [3] Method according to claim 1, wherein the adjustment includes adjusting the pressure surge line with a more aggressive calibration at a vehicle speed below a threshold vehicle speed and adjusting the pressure surge line with a less aggressive calibration at the vehicle speed above the threshold vehicle speed. [4] Method according to claim 1, wherein the adaptation of the pressure surge line is learned over one or more driving cycles of the vehicle. [5] The method of claim 1, wherein adjusting the pressure surge line includes adjusting boundaries for each of a hard pressure surge region and a soft pressure surge region of the compressor map. [6] Method according to claim 2, wherein the fitting comprises using a first lookup table and a second lookup table successively, wherein two of the engine speed, pressure ratio and vehicle speed are entered into the first table and one output of the first table with one remaining of the engine speed, pressure ratio and vehicle speed is entered into the second table and wherein one output of the second table is used to fit the pressure surge line. [7] Method according to claim 2, wherein the adjustment includes determining a first, more aggressive pressure surge line calibration as a function of the compressor pressure ratio, determining a second, less aggressive pressure surge line calibration as a function of the compressor pressure ratio; and merging the first and second pressure surge line calibrations as a weighted function of vehicle speed and / or engine speed. [8] Method according to claim 2, wherein the fitting includes determining a final pressure surge line based on a sum of a first output of a first lookup table and a second output of a second lookup table; and wherein the first table is obtained as a function of engine speed and compressor pressure ratio and the second table is obtained as a function of vehicle speed and compressor pressure ratio. [9] Method according to claim 1, further comprising adjusting an opening of a continuously adjustable compressor return valve during vehicle operation to maintain compressor operation at a higher compressor flow rate than a compressor flow rate of the adapted pressure surge line. [10] Method according to claim 9, wherein the fitting includes estimating a desired throttle mass flow based on engine operating conditions; estimating a threshold compressor flow rate based on the fitted pressure surge line; and adjusting the opening of the CCRV based on a difference between the desired throttle mass flow and the threshold flow rate. [11] Method according to claim 1, wherein adapting the pressure surge line as a function of the vehicle speed includes adapting the pressure surge line with a more aggressive calibration during a tap of the accelerator pedal, which occurs at the lower vehicle speed below a threshold vehicle speed, to a higher vehicle speed above the threshold vehicle speed, and adapting the pressure surge line with a less aggressive calibration during a release of the accelerator pedal from the higher vehicle speed to the lower vehicle speed. [12] Method for a turbocharged engine, comprising: In response to a tap of the accelerator pedal at a higher vehicle speed above a threshold vehicle speed, adjusting the position of a CCRV to operate a compressor at a first higher compressor flow rate than a first pressure surge line; and In response to a tap of the accelerator pedal at a lower vehicle speed below the threshold vehicle speed, the CCRV position is adjusted to operate the engine compressor at a second higher compressor flow rate than a second pressure surge line; where, for a given compressor pressure ratio, a first compressor operating point on the second pressure surge line has a higher compressor flow rate relative to a second compressor operating point on the first pressure surge line. [13] Method according to claim 12, wherein the first pressure surge line is calibrated less aggressively relative to the vehicle speed and wherein the second pressure surge line is calibrated more aggressively relative to the vehicle speed. [14] Method according to claim 12, wherein the CCRV opening is increased by a first, smaller amount in response to tapping the accelerator pedal at higher vehicle speed; and wherein the CCRV opening is increased by a second, larger amount in response to tapping the accelerator pedal at lower vehicle speed. [15] Method according to claim 13, further comprising adjusting the position of a CCRV in response to the release of the accelerator pedal at the higher vehicle speed, operating a compressor at a third, higher compressor flow rate than the first pressure surge line, and adjusting the position of the CCRV in response to the release of the accelerator pedal at the lower vehicle speed, operating the compressor at a fourth, higher compressor flow rate than the second pressure surge line. [16] Vehicle system, comprising: an engine; a compressor to provide a charged air supply to the engine; a compressor return valve positioned in a passage coupling a compressor outlet to a compressor inlet, wherein the position of the valve is continuously adjustable between a fully open and a fully closed position; and a control system with computer-readable instructions, stored in non-volatile memory, for: during vehicle operation, continuous adjustment of a pressure surge line of a standard compressor map with a calibration factor based on one or both of engine speed and vehicle speed; and Adjusting the opening of the compressor return valve based on inlet air flow to maintain compressor operation at a higher compressor flow rate than a pressure surge limit of the adjusted pressure surge line. [17] System according to claim 16, wherein the pressure surge line of the standard compressor card is a compressor card pressure surge line provided by the vehicle manufacturer, which was determined based on component functional tests. [18] System according to claim 16, wherein the adjustment of the pressure surge line includes calibrating the pressure surge line less aggressively at a higher vehicle speed, which is higher than a threshold vehicle speed, and calibrating the pressure surge line more aggressively at a lower vehicle speed, which is lower than the threshold. [19] System according to claim 18, wherein the control further includes instructions to calibrate the pressure surge line less aggressively at an engine speed higher than a first threshold engine speed, to calibrate the pressure surge line less aggressively at an engine speed lower than a second threshold engine speed, and to calibrate the pressure surge line more aggressively at an engine speed lower than the first threshold and higher than the second threshold. [20] System according to claim 16, wherein the degree of aggressiveness of the calibration factor increases with a reduction in vehicle speed below a threshold vehicle speed and wherein the degree of aggressiveness decreases with an increase in vehicle speed above the threshold vehicle speed.

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