GB2507061A

GB2507061A - Method of two-stage turbocharger matching for supporting cylinder deactivation.

Info

Publication number: GB2507061A
Application number: GB1218614.4A
Authority: GB
Inventors: Alberto Vassallo; Roberto Cavallo; Michael A Potter
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2012-10-17
Filing date: 2012-10-17
Publication date: 2014-04-23
Also published as: GB201218614D0

Abstract

A method of controlling an internal combustion engine, comprising a two-stage turbocharger, an exhaust gas recirculation (EGR) valve and a cylinder deactivation system, comprises setting a high pressure (HP) turbine 251, a HP turbine controlled by-pass 252, a low pressure (LP) turbine controlled by-pass 254 and the EGR valve to first or second values taking into account the exhaust flow in the HP and LP by-passes, the expansion ratio in the HP turbine and instantaneous engine speed and load. The HP turbine, the HP and LP by-passes and the EGR valve are also set according to preset values for boost and EGR targets ramp-in. The method may also comprise the step of realizing a cylinders activation or deactivation, as well as controlling the EGR and boost in closed loop. The method may be carried out using a suitable internal combustion engine and control apparatus.

Description

METHOD OF TWO-STAGE TURBOCHERGER MATCHING

FOR SUPPORTING CYLiNDER DEACTIVATION

TECHNICAL FIELD

The present disclosure relates to a method of two-stage turbocharger matching for supporting cylinder deactivation in an internal combustion engine.

BACKGROUND

As known, the majority of internal combustion engines are turbocharged. A turbocharger, is a forced induction device used to allow more power to be produced for an engine of a given size. The benefit of a turbo is that it compresses a greater mass of intake air into the combustion chamber, thereby resulting in increased power andlor efficiency.

Turbochargers are commonly used on truck, car, train and construction equipment engines. They are popularly used with Otto cycle and Diesel cycle internal combustion engines and have also been found useful in automotive fuel cells.

Furthermore modern internal combustion engines, particularly high speed Diesel engines, are more and more requiring the so called "low end torque", which can be achieved by improving the engine boost capability. For turbocharged engines, this requires the capability of fast boost pressure build up, which in turn can be achieved by fast spin up of turbocharger.

Several technologies for turbocharger fast spin up are already known in the technique.

For example, the turbocharger can be realized with a low mass moment of inertia, in other words, lightweight turbine and compressor rotors and shaft. Other solution, and especially for diesel engines, is the Variable Geometry Turbine, in order to get a bigger range with high torque. Alternatively, small turbochargers can be realized in respect to expected engine power or, in order to gain power, a two-stage turbocharger can be used.

The latter is the solution that high specific power diesel engines employ with two turbines and two compressors connected in series. In a typical arrangement of series turbochargers, one turbocharger is mounted on the exhaust manifold and comprises a high pressure stage, and a second turbocharger comprises a low pressure stage. The turbine of the high pressure stage receives exhaust gas from the manifold and the low pressure stage turbine receives exhaust gas from the high pressure stage and discharges it to the atmosphere. The low pressure stage compressor takes in air from the atmosphere, compresses it, and delivers it to the high pressure stage compressor, sometimes through a charge air cooler. The high pressure compressor stage accomplishes a second stage of charge air compression before delivering the charge air to the intake manifold.

It is also known that application of cylinder deactivation seems to become more popular in the future due to higher requirements for fuel economy, or aftertreatment temperature management. Cylinder deactivation is used to reduce the fuel consumption and emissions of an internal combustion engine during light-load operation. In typical light-load driving the driver uses only around 30 percent of an engine's maximum torque. In these conditions, the throttle valve is nearly closed, and the engine needs to work to draw air. This causes an inefficiency known as pumping loss. Some large capacity engines need to be throttled so much at light load that the cylinder pressure at top dead centre is approximately half that of a small 4-cylinder engine. Low cylinder pressure means low fuel efficiency. The use of cylinder deactivation at light load means there are fewer cylinders drawing air from the intake manifold, which works to increase its fluid (air) pressure. Operation without variable displacement is wasteful because fuel is continuously pumped into each cylinder and combusted even though maximum performance is not required. By shutting down half of an engine's cylinders, the amount of fuel being consumed is much less. Between reducing the pumping losses, which increases pressure in each operating cylinder, and decreasing the amount of charge being pumped into the cylinders, fuel consumption can be reduced by 8 to 25 percent in highway conditions. Cylinder deactivation is achieved by keeping the intake and exhaust valves closed for a particular cylinder. Other than valves, a cylinder deactivation system comprises, for example, a cylinder head provided with at least a switchable cam follower, which is actuated by a cam on one side and, directly or indirectly by a gas pressure on the opposite side. By keeping the intake and exhaust valves closed, it creates an "air spring" in the combustion chamber -the trapped exhaust gases (kept from the previous charge burn) are compressed during the piston's upstroke and push down on the piston during its down-stroke. The compression and decompression of the trapped exhaust gases have an equalizing effect -overall, there is virtually no extra load on the engine. In the latest breed of cylinder deactivation systems, the engine management system is also used to cut fuel delivery to the disabled cylinders.

It is to observe that cylinder deactivation, if not coupled to a specific 2-stage TIC matching, leads to significant drawbacks in terms of engine drivability and emissions, especially for versions derived from already turbocharged diesel engines. In order to be successful, cylinder deactivation requires the coupled interruption of both fuel and air feeding to some of the engine cylinders, typically two in a four cylinder engine.

The abrupt reduction of air flow, if not properly managed by the compressor, would cause significant surge events, causing jerking and unacceptable emission drift.

Therefore a need exists for a method of controlling the internal combustion engine, in particular for matching two-stage turbocharger-s for application on gasoline and diesel enginesfitted with cylinder deactivation technology.

An object of this invention is to provide a method of a two-stage turbocharger matching capable to operate the high pressure stage in the cylinder deactivation mode, and a transition strategy for properly managing the deactivation/activation events.

Another object is to provide an apparatus which allows to perform the above method.

These objects are achieved by a method, by an apparatus, by an engine, by a computer program and computer program product, and by an electromagnetic signal having the features recited in the independent claims.

The dependent claims delineate preferred and/or especially advantageous aspects.

SUMMARY

An embodiment of the disclosure provides a method of controlling an internal combustion engine comprising a two-stage turbocharger, an EGR valve and a cylinder deactivation system, the method, being applicable, respectively, after recognizing the need of cylinder deactivation or re-activation transient phases, comprising: -setting a HP turbine, a HP turbine controlled by-pass, a LP turbine controlled by-pass and the EGR valve to first preset values, which take into account a reduction of the exhaust flow in the HP turbine controlled by-pass (252) and LP turbine controlled by-pass, an increase of the expansion ratio in the HP turbine and instantaneous engine speed and load, or -setting the HP turbine, the HP turbine controlled by-pass, the LP turbine controlled by-pass and the EGR valve to second preset values which take into account an increase of the exhaust flow in the HP turbine controlled by-pass and LP turbine controlled by-pass, a reduction of the expansion ratio in the HP turbine and instantaneous engine speed and load, -setting the HP turbine, the HP turbine controlled by-pass, the LP turbine controlled by-pass and the EGR valve to further preset values for boost and EGR targets ramp-in.

Consequently, an apparatus is disclosed for controlling an internal combustion engine of an automotive system, the apparatus comprising: -means for setting a HP turbine, a HP turbine controlled by-pass, a LP turbine controlled by-pass and the EGR valve to first preset values, which take into account a reduction of the exhaust flow in the HP turbine controlled by-pass (252) and LP turbine controlled by-pass, an increase of the expansion ratio in the HP turbine and instantaneous engine speed and load, or 23 -means for setting the HP turbine, the HP turbine controlled by-pass, the LP turbine contralled by-pass and the EGR valve to second preset values which take into account an increase of the exhaust flow in the HP turbine controfled by-pass and LP turbine controlled by-pass, a reduction of the expansion ratio in the HP turbine and instantaneous engine speed and load, -means for setting the HP turbine, the HP turbine controlled by-pass, the LP turbine controlled by-pass and the EGR valve to further preset values for boost and EGR targets ramp-in.

An advantage of this embodiment is that it provides a method for matching the cylinder deactivation technology with high power density engine already fitted with 2-stage turbocharging, avoiding both surge and overspeed risks for the turbocharger.

According to another embodiment of the invention, the method further comprises the step of1 respectively, realizing a cylinder deactivation or a cylinder activation.

An advantage of this embodiment is that the method allows to effectively use cylinder deactivation strategy, to reduce the fuel consumption and emissions of an internal combustion engine during light-load operation.

According to a further embodiment of the invention, the method further comprises the step of controlling in closed loop boost and EGR.

An advantage of this further embodiment is that the method, after that deactivation or re-activation transient phases are completed, allows to restore the conventional EGR closed-loop control based on air target.

The method according to one of its aspects can be carried out with the help of a computer program comprising a program-code for carrying out all the steps of the method described above, and in the form of computer program product comprising the computer program.

The computer program product can be embodied as a control apparatus for an internal combustion engine, comprising an Electronic Control Unit (ECU), a data carrier associated to the ECU, and the computer program stored in a data carrier, so that the control apparatus defines the embodiments described in the same way as the method. In this case, when the control apparatus executes the computer program all the steps of the method described above are carried out.

The method according to a further aspect can be also embodied as an electromagnetic signal1 said signal being modulated to carry a sequence of data bits which represents a computer program to carry out all steps of the method.

A still further aspect of the disclosure provides an internal combustion engine specially arranged for carrying out the method claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an automotive system.

Figure 2 is a section of an internal combustion engine belonging to the automotive system of figure 1.

Figure 3 is a simplified scheme of an internal combustion engine provided with a two-stage turbocharger.

Figure 4 is a flowchart of a method of controlling the transient phase of cylinder deactivation.

Figure 5 is a flowchart of a method of controlling the transient phase of cylinder re-activation.

DETAILED DESCRIPTION OF THE DRAWINGS

Some embodiments may include an automotive system 100, as shown in Figures land 2, that includes an internal áombustion engine (ICE) 110 having an engine block 120 defining at least one cylinder 125 having a piston 140 coupled to rotate a crankshaft 145.

A cylinder head 130 cooperates with the piston 140 to define a combustion chamber 150.

A fuel and air mixture (not shown) is disposed in the combustion chamber 150 and ignited1 resulting in hot expanding exhaust gasses causing reciprocal movement of the piston 140. The fuel is provided by at least one fuel injector 160 and the air through at least one intake port 210. The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 in fluid communication with a high pressure fuel pump 180 that increase the pressure of the fuel received a fuel source 190. Each of the cylinders 125 has at least two valves 215, actuated by a camshaft 135 rotating in time with the crankshaft 145. The valves 215 selectively allow air into the combustion chamber 150 from the port 210 and alternately allow exhaust gases to exit through a port 220. In some examples, a cam phaser 155 may selectively vary the timing between the camshaft 135 and the crankshaft 145.

The air may be distributed to the air intake port(s) 210 through an intake manifold 200.

An air intake duct 205 may provide air from the ambient environment to the intake manifold 200. In other embodiments, a throttle body 330 may be provided to regulate the flow of air into the manifold 200. In still other embodiments, a forced air system such as a turbocharger 230, having a compressor 240 rotationally coupled to a turbine 250, may be provided. Rotation of the compressor 240 increases the pressure and temperature of the air in the duct 205 and manifold 200. An intercooler 260 disposed iii the duct 205 may reduce the temperature of the air. The turbine 250 rotates by receiving exhaust gases from an exhaust manifold 225 that directs exhaust gases from the exhaust ports 220 and through a series of vanes prior to expansion through the turbine 250. The exhaust gases exit the turbine 250 and are directed into an exhaust system 270, This example shows a variable geometry turbine (VGT) 250 with a VGT actuator 290 arranged to move the vanes to alter the flow of the exhaust gases through the turbine 250. In other embodiments, the turbocharger 230 may be fixed geometry andlor include a waste gate.

A further embodiment, as the one shown in Fig. 3, comprises a two-stage turbocharger, with one high pressure stage turbocharger and one low pressure stage turbocharger.

The turbine of the high pressure stage 251 receives exhaust gas from the manifold 225.

It could be a fixed or a variable geometry turbine and is provided with a controlled by-pass circuit 252. The low pressure stage turbine 253 receives exhaust gas from the high pressure stage and discharges it to the atmosphere. It could also be a VOT turbine or, as in the example of figure 3, provided with a controlled by-pass circuit (Waste gate) 254.

The low pressure stage compressor 243 takes in air from the atmosphere, compresses it, and delivers it to the high pressure stage compressor 241. The high pressure compressor stage accomplishes a second stage of charge air compression before delivering the charge air to the intake manifold 200. As shown in Fig. 3, it can be provided with a controlled by-pass circuit 242.

The exhaust system 270 may include an exhaust pipe 275 having one or more e*haust aftertreatment devices 280. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some examples of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, particulate filters (DPF) or a combination of the last two devices, i.e. selective catalytic reduction system comprising a particulate filter (SCRF). Some embodiments may include an exhaust gas recirculation (EGR) system 300 coupled between the exhaust manifold 225 and the intake manifold 200. The EGR system 300 may include an EGR cooler 310 to reduce the temperature of the exhaust gases in the EGR system 300.

An EGR valve 320 regulates a flow of exhaust gases in the EGR system 300.

The automotive system 100 may further include an electronic control unit (ECU) 450 ri communication with one or more sensors and/or devices associated with the ICE 110 and equipped with a data carrier 40. The ECU 450 may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE 110. The sensors include, but are not limited to, a mass airflow and temperature sensor 340, a manifold pressure and temperature sensor 350, a combustion pressure sensor 360, coolant and oil temperature and level sensors 380, a fuel rail pressure sensor 400, a cam position sensor 410, a crank position sensor 420, exhaust pressure and temperature sensors 430, an EGR temperature sensor 440, and an accelerator pedal position sensor 445. Furthermore, the ECU 450 may generate output signals to various control devices that are arranged to control the operation of the ICE 1101 including, but not limited to, the fuel injectors 160, the throttle body 330, the EGR Valve 320, the VGT actuator 290, and the cam phaser 155. Note, dashed lines are used to indicate communication between the ECU 450 and the various sensors and devices, but some are omitted for clarity.

Turning now to the ECU 450, this apparatus may include a digital central processing unit (CPU) in communication with a memory system and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system, and send and receive signals to/from the interface bus. The memory system may include various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analog and/or digital signals to/from the various sensors and control devices.

The program may embody the methods disclosed herein, allowing the CPU to carryout out the steps of such methods and control the ICE 110.

The method according to the present invention aims to provide the opportunity to match the cylinder deactivation technology with high power density engine already fitted with two-stage turbocharging, with an algorithm for the transition management. 1].

Before illustrating the method according to the invention, some background considerations must be provided. Some preliminary analysis have been carried out on injection deactivation and valve deactivation on two cylinders, that is to say, cutting both air and fuel on two cylinders.

S

As expected, when running in cylinder deactivation conditions, strong air mass flow reduction occurs coupled to a higher boost request for firing cylinders, which causes a significant deterioration of compressor operating conditions. In addition, particularly for Diesel engines, the higher load on firing cylinders compromises the indicated thermodynamic efficiency due to combustion duration increase. On the other side, cylinder deactivation leads to an increase of exhaust temperature up to about 190 K (for 2 bar bmep average engine load).

However, the main drawback is that, due to remarkable reduction of air flow consumption at given speed and toad corresponding compressor operating points shift towards lower flow-rates and to higher pressure ratios: this would likely lead to surge or noise issues on compressor.

Therefore, in order to match the two stage turbocharger with the cylinder deactivation strategy, it is mandatory the sizing of the high-pressure turbine 251 (and consequently of the low-pressure turbine 253, as they need proper overlap for managing the transition), considering the requirements of flow reduction following a cylinder deactivation, i.e. halving the intake airflow in a quite abrupt way.

In order to accomplish this, the HP compressor 241 map sizing needs to consider, as worst case condition, the halving of normalized airflow (in the engine operating area that may be subjected to cylinder deactivation). This will require a proper location of the compressor surge line which may be more stringent than the conventional requirements.

In the apposite case, when cylinder reactivation is required, the almost doubled intake air flow in a quite abrupt way causes risks of HP turbocharger overspeed. This also leads to more stringent requirements for the turbocharger matching.

These considerations means that the sudden transition phases, both for cylinder deactivation and reactivation needs to be carefully managed. This new method consists of a strategy for managing such transient avoiding respectively surge and overspeed problems.

With reference to Fig. 4, if a request of cylinder deactivation 20 occurs and a sudden transition is required because of engine air consumption halved 21, a specific transition procedure to discharge air through the exhaust is enacted, based on the coordination of all HP and LP turbines actuators and EGR valve. In particular, the method will set 22 the HP turbine 251, the HP turbine controlled by-pass 252, the LP turbine controlled by-pass 254 and the EGR valve 300 to first preset values for avoiding surge effects.

As a matter of fact, this set requires that the EGR valve 300 is opened to a calibratable duty value as a function of engine speed and load, and such a pre-set value is mapped on the ECU. The transition from the actual operating duty value for EGR valve 300 before cylinder deactivation to the new calibratable pre-set for cylinder deactivation follows a certain calibratable ramp and is started after a calibratable time delay depending on instantaneous engine speed and load at the time the deactivation decision was taken. Once the boost pressure in the intake manifold has dropped to a calibratable value close to the desired one for the deactivated strategy, which depends on the new load at which the remaining firing cylinder operate, a further action is enacted on the S following actuators: the HP turbine 251 set1 HP turbine controlled by-pass 252 and the LP turbine controlled by-pass 254, are all ramped to calibratable pie-set values. This set of values specific for cylinder deactivation triggers a significant reduction of exhaust flow through the HP turbine controlled by-pass 252, a consequent increase of the expansion ratio through the HP turbine 251 set and finally a reduction of the LP turbine controlled by-pass 254 exhaust flow, The values for each actuator are calibrated based, on one side, on the reduction of total exhaust gas flow and enthalpy at the engine outlet, and, on the other side, on the contemporary reduction of fresh charge coupled to a request of higher boost level, whose combination in turn require a corresponding increase of the expansion ratio through the HP turbine 251 set, and through the LP turbine 253, by closing the relevant actuators.

Once the above described anti-surge maneuver has been completed, the engine effectively starts the cylinder deactivation 24, as now can be riskless performed. As the cylinder deactivation involves running different boost and different amount of EGR rate as previously anticipated, in order to quickly transit to the new engine operating point, a second dedicated set of values for the actuators is needed and the method foresees the setting 23 of the HP turbine 251, the HP turbine controlled by-pass 252, the LP turbine controlled by-pass 254 and the EGR valve 300 to further preset values for boost and EGR targets ramp-in. This second ramp of actuators sets is activated in parallel to cylinder deactivation, and following the exhaustion of the consequent transient in engine operating parameters based on a calibratable differential map for air flow and boost levels, the conventional EGR closed-loop control based on air target is re-established for controlling in closed loop 25 the boost and EGR levels.

In the opposite case, (see Fig-5) when the request of cylinder rS_activation 26 occurs based on the control logic, and again a sudden transition is required because of engine air consumption roughly doubled 27, HP turbocharger stage might run close to overspeed conditions and therefore a specific transition procedure to prevent any overshoot in HP turbo speed is required. In particular, the method will set 28 the HP turbine 251, the HP turbine controlled by-pass 252, the LP turbine controlled by-pass 254 and the EGR valve 300 to second preset values for avoiding high pressure turbocharger overspeed.

As a matter of fact, this new set requires opposite maneuvers than those described for cylinder deactivation: the EGR valve 300 is opened to a calibratable duty value as a function of engine speed and load, and such a pre-set value is mapped on the ECU. The transition from the actual operating duty value for EGR valve 300 for cylinder deactivation mode to the new calibratable pre-set for normal engine operation follows a certain calibratable ramp and is started after a calibratable time delay depending on instantaneous engine speed and load at the time the reactivation decision was taken.

Once the boost pressure in the intake manifold has decreased to a calibratable value close to the desired one for the normal operation, which depends on the new load at which all the cylinders will fire, a further action is enacted on the following actuators: the HP turbine 251 set, HP turbine controlled by-pass 252 and the LP turbine controlled by-pass 254, are all ramped to calibratable pre-set values. This set of values specific for cylinder reactivation triggers a significant increase of exhaust flow through the HP turbine controlled by-pass 252, a consequent reduction of the expansion ratio through the HP turbine 251 set and finally an increase of the LP turbine controlled by-pass 254 exhaust flow-The more open values for each turbocharger actuator are caiibrated based, on one side, on the expected increase of total exhaust gas flow and enthalpy at the engine outlet, and, on the other side, on the contemporary increase of fresh charge coupled to a request of lower boost level by all the cylinders, whose combination in turn require a corresponding drop of the expansion ratio through the HP turbine 251 set1 and through the LP turbine 253, by opening the relevant actuators.

Once turbochargers overspeed has been prevented, the cylinder re-activation 30 can be effectively and riskless performed. As the engine now firing on all cylinders will run different boost and different amount of EGS rate, and in order to quickly transit to the new engine operating point, a second dedicated set of values for the actuators is needed and the method foresees the setting 29 of the HP turbine 251, the HP turbine controlled by-pass 252, the LP turbine controlled by-pass 254 and the EGR valve 300 to further preset values for boost and EGR targets ramp-in. This final ramp of actuators sets is activated in parallel to cylinder reactivation, and following the exhaustion of the consequent transient in engine operating parameters based on a calibratable differential map for air flow and boost levels, the conventional EGR closed-loop control based on air target is re-established for controlling in closed loop 25 the boost and EGR levels during engine normal operation firing on all cylinders.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

REFERENCE NUMBERS block

21 block 22 block 23 block 24 block block 26 block 27 block 28 block 29 block block 31 block data carrier 100 automotive system internal combustion engine engine block cylinder cylinder head 135 camshaft piston crankshaft combustion chamber cam phaser 160 fuel injector fuel rail fuel pump fuel source intake manifold 205 air intake pipe 210 intake port 215 valves 220 port 225 exhaust manifold 230 turbocharger 240 compressor 241 HP compressor 242 HP compressor controlled by-pass 243 LP compressor 245 turbocharger shaft 250 Variable geometry turbine (VGT) 251 HP turbine 252 HP turbine controlled by-pass 253 LP turbine 254 LP turbine controlled by-pass (waste gate) 260 intercooler 270 exhaust system 275 exhaust pipe 280 aftertreatment devices 290 VGT actuator 300 exhaust gas recirculation system 310 EGR cooler 320 EGR valve 330 throttle body 340 mass airflow and temperature sensor 350 manifold pressure and temperature sensor 360 combustion pressure sensor 380 coolant temperature and level sensors 385 lubricating oil temperature and level sensor 390 metal temperature sensor 400 fuel rail pressure sensor 410 cam position sensor 420 crank position sensor 430 exhaust pressure and temperature sensors 440 EGR temperature sensor 445 accelerator position sensor 446 accelerator pedal 450 ECU

Claims

CLAIMS1. Method of controlling an internal cornbustion engine (110) comprising a two-stage turbocharger, an EGR valve (300) and a cylinder deactivation system, the method, being applicable, respectively, after recognizing the need of cylinder deactivation (20) or re-activation (26) transient phases, comprising: -setting (22) a HP turbine (251), a HP turbine controlled by-pass (252), a LP turbine controlled by-pass (254) and the EGR valve (300) to first preset values, which take into account a reduction of the exhaust flow in the HP turbine controlled by-pass (252) and LP turbine controlled by-pass (254), an increase of the expansion ratio in the HP turbine (251) and instantaneous engine speed and load, or -selling (28) the HP turbine (251), the HP turbine controlled by-pass (252), the LP turbine controlled by-pass (254) and the EGR valve (300) to second preset values which take into account an increase of the exhaust flow in the HP turbine controlled by-pass (252) and LP turbine controlled by-pass (254), a reduction of the expansion ratio in the HP turbine (251) and instantaneous engine speed and load, -setting (23, 29) the F-JR turbine (251), the I-IF turbine controlled by-pass (252), the LP turbine controlled by-pass (254) and the EGR valve (300) to further preset values for boost and EGR targets ramp-in.
2. Method according to claim 1, wherein it further comprises the step of, respectively, realizing a cylinder deactivation (24) or a cylinder activation (30).
3. Method according to claim 1 or 2, wherein it further comprises the step of controlling in closed loop (25) boost and EGR.
4. Internal combustion engine (110) of an automotive system (100), the engine comprising an EGR valve (300), a two-stage turbocharger, with a high pressure turbine (251), a high pressure turbine controlled by-pass circuit (252), a low pressure turbine (253), a low pressure turbine controlled by-pass circuit (254), the automotive system (190) being configured for carrying out the method according to any of the claims 1-3.
5. A computer program comprising a computer-code suitable for performing the method according to any of the claims 1-3.
6. Computer program product on which the computer program according to claim 5 is stored -
7. Control apparatus for an internal combustion engine, comprising an Electronic Control Unit (450), a data carner (40) associated to the Electronic Control Unit (450) and a computer program according to claim 5 stored in the data carrier (40).
8. An electromagnetic signal modulated as a carrier for a sequence of data bits representing the computer program according to claim 5. 22 -