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A vehicle system controls a compression ignition internal combustion engine equipped with a supercharger system including a plurality of superchargers. The compression ignition internal combustion engine has an exhaust gas recirculation (EGR) system. The vehicle system determines a desired intake ma

A vehicle system controls a compression ignition internal combustion engine equipped with a supercharger system including a plurality of superchargers. The compression ignition internal combustion engine has an exhaust gas recirculation (EGR) system. The vehicle system determines a desired intake manifold supercharging state (tQac) and a desired EGR rate (Megr). The vehicle system includes control logics, each having a first input parameter and a second input parameter, for determining desired set points (Rvnt1 & Rvnt2) for the plurality of superchargers, respectively. The desired set points are used to control the plurality of superchargers, respectively. The vehicle system also includes control logic for determining the first input parameters in response to the desired intake manifold supercharging state. The vehicle system further includes control logic for determining the second input parameters in response to the desired EGR rate.

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1. A system for controlling a vehicle having a compression ignition internal combustion engine, the compression ignition engine having a plurality of combustion cylinders, an intake manifold, an exhaust gas recirculation (EGR) system and a supercharger system including a plurality of superchargers,

1. A system for controlling a vehicle having a compression ignition internal combustion engine, the compression ignition engine having a plurality of combustion cylinders, an intake manifold, an exhaust gas recirculation (EGR) system and a supercharger system including a plurality of superchargers, the system comprising:control logic for determining a desired intake manifold supercharging state; control logic for determining a desired EGR rate; control logics, each having a first input parameter and a second input parameter, for determining desired set points for the plurality of superchargers, respectively, the desired set points being used to control the plurality of superchargers, respectively; control logic for determining the first input parameters in response to the desired intake manifold supercharging state; and control logic for determining the second input parameters in response to the desired EGR rate. 2. The system as claimed in claim 1,wherein the control logic for determining the first input parameters includes: control logic for determining an intake air amount equivalence value as a function of the desired intake manifold supercharging state; wherein the control logic for determining the second input parameters includes: control logic for determining an actual EGR rate as a function of the desired EGR rate. 3. The system as claimed in claim 1,wherein the control logic for determining the first input parameters includes: control logic for determining proportion of each to the total of the first input parameters. 4. The system as claimed in claim 3,wherein the control logic for determining the second input parameters includes: control logic for determining proportion of each to the total of the second input parameters. 5. The system as claimed in claim 3, wherein the supercharger system includes a primary turbocharger and a secondary turbocharger, which operate sequentially.6. The system as claimed in claim 4, wherein the supercharger system includes a primary turbocharger and a secondary turbocharger, which operate sequentially.7. The system as claimed in claim 5, wherein the control logic for determining proportion of each to the total of the first input parameters includes:control logic for determining a distribution ratio in response to the engine operating conditions. 8. The system as claimed in claim 6, wherein the control logic for determining proportion of each to the total of the first input parameters includes:control logic for determining a distribution ratio in response to the engine operating conditions. 9. The system as claimed in claim 7, wherein the engine operating conditions include the engine speed, and wherein the engine speed increases to vary the distribution ratio in such a direction as to decrease the share of work to the primary turbocharger as the engine speed increases, the primary turbocharger being adapted to do almost all work at low engine speeds.10. The system as claimed in claim 8, wherein the engine operating conditions include the engine speed, and wherein the engine speed increases to vary the distribution ratio in such a direction as to decrease the share of work to the primary turbocharger is decreased as the engine speed increases, the primary turbocharger being adapted to do almost all work at low engine speeds.11. The system as claimed in claim 7, wherein the engine operating conditions include the engine speed and the engine load, and wherein the engine speed and load shift toward operating conditions at high engine speeds with heavy engine load to vary the distribution ratio in such a direction as to decrease the share of work to the primary turbocharger as the engine speed and load shift toward operating conditions at high engine speeds with heavy engine load, the primary turbocharger being adapted to do almost all work at low engine speeds.12. The system as claimed in claim 8, wherein the engine operating conditions include the engine speed and the engine load, and wherein the engine speed and load shift toward operating conditions at high engine speeds with heavy engine load to vary the distribution ratio in such a direction as to decrease the share of work to the primary turbocharger as the engine speed and load shift toward operating conditions at high engine speeds with heavy engine load, the primary turbocharger being adapted to do almost all work at low engine speeds.13. The system as claimed in claim 7, wherein the engine operating conditions include an exhaust gas flow rate equivalence value that is determined as a function of an intake air amount, a desired fuel injection amount, and the engine speed.14. The system as claimed in claim 8, wherein the engine operating conditions include an exhaust gas flow rate equivalence value that is determined as a function of an intake air amount, a desired fuel injection amount, and the engine speed.15. The system as claimed in claim 4,wherein the supercharger system includes a primary turbocharger and a secondary turbocharger which work sequentially; wherein the control logic for determining proportion of each to the total of the first input parameters includes: control logic for determining a first distribution ratio in response to the engine operating conditions; and wherein the control logic for determining proportion of each to the total of the second input parameters includes: control logic for determining a second distribution ratio in response to the engine operating conditions. 16. The system as claimed in claim 15, wherein the engine operating conditions, which are used in determining the second distribution ratio, include the engine speed.17. The system as claimed in claim 15, wherein the engine operating conditions used in determining the second distribution ratio include the engine speed and the engine load.18. The system as claimed in claim 15, wherein the EGR system has an inlet and an outlet, and wherein the engine operating conditions used in determining the second distribution ratio include a contribution parameter indicative of contribution of the primary and secondary turbochargers to pressure at the inlet of the EGR system.19. The system as claimed in claim 18, wherein the contribution parameter is one of the engine speed and the engine load.20. The system as claimed in claim 18, wherein the contribution parameter is an exhaust gas flow rate equivalence value that is determined as a function of an intake air amount, a desired fuel injection amount, and the engine speed.21. The system as claimed in claim 4,wherein the supercharger system includes a primary turbocharger and a secondary turbocharger which work sequentially; and wherein the second distribution ratio is equal to the first distribution ratio. 22. The system as claimed in claim 3, wherein the supercharger system includes a first turbocharger that is capable of providing sufficient supply of intake air required by one half of the plurality of combustion cylinders, and a second turbocharger that is capable of providing sufficient supply of intake air required by the other half of the plurality of combustion cylinders; and wherein the first and second turbochargers work simultaneously.23. The system as claimed in claim 22, wherein the distribution ratio is set such that the proportions of the first input parameters are equal to each other.24. The system as claimed in claim 4,wherein the supercharger system includes a first variable geometry turbocharger that is capable of providing sufficient supply of intake air required by one half of the plurality of combustion cylinders, and a second variable geometry turbocharger that is capable of providing sufficient supply of intake air required by the other half of the plurality of combustion cylinders; and wherein the first and second turbochargers work simultaneously; wherein the engine has a first exhaust manifold and a second exhaust manifold coupled to the one half and the other half of the plurality of combustion cylinders, respectively; wherein the EGR system includes an EGR duct connecting the first exhaust manifold to the intake manifold; wherein the first variable geometry turbocharger includes a turbine having an inlet coupled to the first exhaust manifold and an outlet; wherein the second variable geometry turbocharger includes a turbine having an inlet coupled to the second exhaust manifold and an outlet; wherein the first distribution ratio is set such that the proportions of the first input parameters are equal to each other; and wherein the second distribution ratio is set such that the proportions of the second input parameters of the control logics for determining desired set points for the first and second various geometry turbochargers are 1 and zero, respectively. 25. The system as claimed in claim 24, wherein the desired set points for the first and second variable geometry turbochargers are set such that work performed by the first variable geometry turbocharger is equal to work performed by the second variable geometry turbocharger.26. The system as claimed in claim 1, wherein the supercharger system includes a plurality of variable geometry turbochargers, each variable geometry turbocharger having a turbine including turbine nozzles; and wherein each of the desired set points is indicative of a ratio of opening position of the turbine nozzles of each of the turbines to the fully opened position thereof.27. The system as claimed in claim 1, wherein the supercharger system includes a plurality of fixed geometry turbochargers, each fixed geometry turbocharger having a turbine including a waste gate; and wherein each of the desired set points is indicative of opening position of the waste gate of each of the turbines.28. A method of controlling a vehicle having a compression ignition internal combustion engine, the compression ignition engine having a plurality of combustion cylinders, an intake manifold, a first exhaust manifold and a second exhaust manifold, each coupled with a plurality of the combustion cylinders, an exhaust gas recirculation (EGRI system including an EGR duct connecting the first and second exhaust manifolds to the intake manifold, and a supercharger system including a first variable geometry turbocharger (VGT) and a second VGT, the first VGT including a first turbine having an inlet fluidly coupled with the first exhaust manifold and an outlet, and a first compressor having an inlet and an outlet, the second VGT including a second turbine having an inlet fluidly coupled with the second exhaust manifold and an outlet, and a second compressor having an inlet and an outlet, the method comprising:determining a desired intake air amount as a desired intake manifold supercharging state; determining a desired EGR rate; determining a first desired set point for the first VGT in response to a first input parameter and a second input parameter, the first desired set point being used to control the first VGT so as to track the first desired set point; determining a second desired set point for the second VGT in response to a first input parameter and a second input parameter, the second desired set point being used to control the second VGT so as to track the second desired set point; determining the first input parameters in response to the desired intake manifold supercharging state; and determining the second input parameters in response to the desired EGR rate. 29. The method as claimed in claim 28,wherein the determining the first input parameters includes: determining an intake air amount equivalence value as a function of the desired intake manifold supercharging state; and wherein the determining the second input parameters includes: determining an actual EGR rate as a function of the desired EGR rate. 30. The method as claimed in claim 29,wherein the determining the first input parameters includes: determining proportion of each to the total of the first input parameters. 31. The method as claimed in claim 30,wherein the determining the second input parameters includes: determining proportion of each to the total of the second input parameters. 32. The method as claimed in claim 30,wherein the determining the first input parameters further includes: varying the proportion of each of the first input parameters to the total thereof in response to at least one of the engine speed and load. 33. The method as claimed in claim 32,wherein the determining the second input parameters further includes: varying the proportion of each of the second input parameters to the total thereof in response to at least one of the engine speed and load. 34. The method as claimed in claim 30,wherein the determining the first input parameters includes: multiplying the intake air amount equivalence value with a distribution ratio to give one of the first input parameters; and subtracting the one of the first input parameters from the intake air amount equivalence value to give the other of the first input parameters. 35. The method as claimed in claim 34,wherein the determining the second input parameters includes: multiplying the actual EGR rate with a second distribution ratio to give one of the second input parameters; and subtracting the one of second input parameters from the actual EGR rate to give the other of the second input parameters. 36. The method as claimed in claim 34, wherein the determining the first input parameters includes:varying the distribution ratio in response to at least one of the engine speed and load. 37. The method as claimed in claim 29, further comprising:determining a base fuel injection amount based on a current value of the engine speed and a current value of an accelerator pedal opening angle; and determining a desired fuel injection amount by correcting the base fuel injection amount with a current value of the engine coolant temperature. 38. The method as claimed in claim 37, wherein the determining a desired EGR rate includes:determining a base desired EGR rate based on a current value of the desired fuel injection amount and a current value of the engine speed; and correcting the base desired EGR rate with a coolant temperature coefficient that is determined in response to a current value of the engine coolant temperature to determine the desired EGR rate. 39. The method as claimed in claim 38, further comprising:determining a base volumetric efficiency equivalence value based on a current value of the desired fuel injection amount and a current value of the engine speed. 40. The method as claimed in claim 39, wherein the determining an actual EGR rate is governed by the following equation:Megrd=Megr×Kkin×Ne×KE2#+Megrdn?1×(1?Kkin×Ne×KE2#) whereMegrd represents an actual EGR rate at an inlet valve of combustion cylinder, Megrdn?1 represents a preceding value of the Megrd obtained a predetermined time interval ago, Megr represents a current value of the desired EGR rate, Kkin=Kin×KVOL#VE represents the displacement of compression ignition internal combustion engine, NC represents the number of combustion cylinders, VM represents the capacity of the engine induction system, Ne represents the engine speed, and KE2# represents a constant. 41. The method as claimed in claim 40, wherein the determining a desired intake air amount (tQac) is governed by the following equation: where where Mqdrv represents the base fuel injection amount, Tfbya represents a desired equivalence ratio, BLAMB#=14.7, Tlamb represents a desired excess air ratio. 42. The method as claimed in claim 41, wherein the determining an intake air amount equivalence value (tQas0) is governed by the following equation: where tQac represents a desired intake air amount, Qsol represents a desired fuel injection amount, QFGAN# represents a gain, Ne represents the engine speed, KCON# represents a constant. 43. A computer readable storage medium having information stored thereon representing instructions to control a vehicle having a compression ignition internal combustion engine, the compression ignition internal combustion engine having an intake manifold, an exhaust gas recirculation (EGR) system, and a supercharger system including a first variable geometry turbocharger (VGT) and a second VGT, the computer readable storage medium comprising:instructions for determining a desired intake air amount as a desired intake manifold supercharging state; instructions for determining a desired EGR rate; instructions for determining a first desired set point for the first VGT in response to a first input parameter and a second input parameter, the first desired set point being used to control the first VGT so as to track the first desired set point; instructions for determining a second desired set point for the second VGT in response to a first input parameter and a second input parameter, the second desired set point being used to control the second VGT so as to track the second desired set point; instructions for determining the first input parameters in response to the desired intake manifold supercharging state; and instructions for determining the second input parameters in response to the desired EGR rate. 44. The computer readable storage medium as claimed in claim 43,wherein the instructions for determining the first input parameters includes: instructions for determining an intake air amount equivalence value as a function of the desired intake manifold supercharging state; and wherein the instructions for determining the second input parameters include: instructions for determining an actual EGR rate as a function of the desired EGR rate. 45. The computer readable storage medium as claimed in claim 43,wherein the instructions for determining the first input parameters includes: instructions for determining proportion of each to the total of the first input parameters. 46. The computer readable storage medium as claimed in claim 45,wherein the instructions for determining the second input parameters includes: instructions for determining proportion of each to the total of the second input parameters. 47. A compression ignition internal combustion engine, comprising:a plurality of combustion cylinders; an intake manifold coupled with the plurality of combustion cylinders; a first exhaust manifold and a second exhaust manifold, each of the first and second exhaust manifolds being coupled with a plurality of the combustion cylinders; an exhaust gas recirculation (EGR) system including an EGR duct fluidly interconnecting each of the first and second exhaust manifolds and at least one of the first and second intake manifolds; a first variable geometry turbocharger including a first turbine having an inlet and an outlet, and a first compressor having an inlet and an outlet, the first turbine inlet being fluidly coupled with the first exhaust manifold, the first compressor outlet being fluidly coupled with the intake manifold, the first turbocharger including a controllable first actuator for varying the first turbocharger geometry; a second variable geometry turbocharger including a second turbine having an inlet and an outlet, and a second compressor having an inlet and an outlet, the second turbine inlet being fluidly coupled with the second exhaust manifold, the second compressor outlet being fluidly coupled with the intake manifold, the second turbocharger including a controllable second actuator for varying the second turbocharger geometry; control logic for determining a desired intake manifold supercharging state; control logic for determining a desired EGR rate; control logic, having a first input parameter and a second input parameter, for determining a first desired set point (Rvnt1) for the first variable geometry turbocharger; control logic, having a first input parameter and a second input parameter, for determining a second desired set point for the second variable geometry turbocharger; control logic for determining the first input parameters in response to the desired intake manifold supercharging state; control logic for determining the second input parameters in response to the desired EGR rate; control logic for controlling the first actuator to change the current first turbocharger geometry so as to track the first desired set point; and control logic for controlling the second actuator to change current second turbocharger geometry so as to track the second desired set point. 48. The compression ignition internal combustion engine as claimed in claim 47,wherein the control logic for determining the first input parameters includes: control logic for determining an intake air amount equivalence value as a function of the desired intake manifold supercharging state; and wherein the control logic for determining the second input parameters includes: control logic for determining an actual EGR rate as a function of the desired EGR rate. 49. The compression ignition internal combustion engine as claimed in claim 48, wherein the control logic for determining the first input parameters includes:control logic for multiplying the intake air amount equivalence value with a distribution ratio to give one of the first input parameters; and control logic for subtracting the one of the first input parameters from the intake air amount equivalence value to give the other of the first input parameters. 50. The compression ignition internal combustion engine as claimed in claim 49, wherein the control logic for determining the first input parameters includes:control logic for varying the distribution ratio in response to at least one of engine speed, engine load, and an intake air amount equivalence value. 51. A compression ignition internal combustion engine, comprising:a plurality of combustion cylinders; an intake manifold coupled with the plurality of combustion cylinders; a first exhaust manifold and a second exhaust manifold, each of the first and second exhaust manifolds being coupled with a plurality of the combustion cylinders; an exhaust gas recirculation (EGR) system including an EGR duct fluidly interconnecting the first exhaust manifold and the intake manifold; a first variable geometry turbocharger including a first turbine having an inlet and an outlet, and a first compressor having an inlet and an outlet, the first turbine inlet being fluidly coupled with the first exhaust manifold, the first compressor outlet being fluidly coupled with the intake manifold, the first turbocharger including a controllable first actuator for varying the first turbocharger geometry; a second variable geometry turbocharger including a second turbine having an inlet and an outlet, and a second compressor having an inlet and an outlet, the second turbine inlet being fluidly coupled with the second exhaust manifold, the second compressor outlet being fluidly coupled with the intake manifold, the second turbocharger including a controllable second actuator for varying the second turbocharger geometry; control logic for determining a desired intake manifold supercharging state; control logic for determining a desired EGR rate; control logic, having a first input parameter and a second input parameter, for determining a first desired set point for the first variable geometry turbocharger; control logic, having a first input parameter, for determining a second desired set point for the second variable geometry turbocharger; control logic for determining the first input parameters in response to the desired intake manifold supercharging state; control logic for determining the second input parameter in response to the desired EGR rate; control logic for controlling the first actuator to change the current first turbocharger geometry so as to track the first desired set point; and control logic for controlling the second actuator to change the current second turbocharger geometry so as to track the second desired set point. 52. A system for controlling a vehicle having a compression ignition internal combustion engine, the compression ignition internal combustion engine having a plurality of combustion cylinders, an intake manifold, an exhaust gas recirculation (EGR) system, and a supercharger system including a plurality of superchargers, the system comprising:means for determining a desired intake manifold supercharging state; means for determining a desired EGR rate; a plurality of means, each having a first input parameter and a second input parameter, for determining desired set points for the plurality of superchargers, respectively, the desired set points being used to control the plurality of superchargers, respectively; means for determining the first input parameters in response to the desired intake manifold supercharging state; and means for determining the second input parameters in response to the desired EGR rate.