Turbocharger flow control
AssigneeGM Global Technology Operations LLC
InventorsYue-Yun Wang, Ibrahim Haskara, Kevin Andrew Gady
Life of this patent
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Abstract
A method for controlling a turbocharger is provided. The turbocharger has a turbine operatively connected to an exhaust of an internal combustion engine, and a compressor operatively connected to an intake of the engine. The method includes determining a boost pressure command for the compressor. The boost pressure command is configured to provide sufficient combustion reactant for the engine. The method includes calculating a compressor power from the determined boost pressure command, and calculating a turbine flow from the calculated compressor power. The method commands the turbocharger to operate at the calculated turbine flow.
Claims12
A method for controlling a turbocharger having a turbine operatively connected to an exhaust of an internal combustion engine and having a compressor operatively connected to an intake of the engine, the method comprising:
- determining a boost pressure command for the compressor, wherein the boost pressure command is configured to provide sufficient combustion reactant for the engine;
- calculating a compressor power from the determined boost pressure command;
- calculating a turbine flow from the calculated compressor power;
- and
- commanding the turbocharger to operate at the calculated turbine flow.
A method for controlling a turbocharger having a turbine operatively connected to an exhaust of an internal combustion engine and having a compressor operatively connected to an intake of the engine, the method comprising:
- calculating a boost pressure command for the compressor from the equation:
- P
- i
- =
- 2
- ·
- R
- ·
- T
- i
- ·
- m
- .
- c
- n
- ·
- D
- ·
- η
-
- (
- EGRf
- ,
- n
- )
- wherein R is the ideal gas constant, Ti is temperature at the intake, mc is charge flow command, n is rotational speed of the engine, D is engine displacement, and η is engine volumetric efficiency, which is calculated as a function of EGRf, an EGR fraction and the rotational speed of the engine;
- calculating a compressor flow from the equation:
- Qc={dot over (m)}a·(Ta/Pa)
- wherein ma is mass flow to the compressor, Ta is atmospheric temperature, and Pa is atmospheric pressure;
- calculating a compressor pressure ratio from the equation:
- Prc=Pi/Pa
- wherein, Pi is the calculated boost pressure command and Pa is atmospheric pressure;
- calculating a compressor power from the equation:
- Ec=(Tex/Pto)·{dot over (m)}a·cp·Ta·(a1+a2Qc+a3Qc2+a4Prc+a5Prc2+a6QcPrc)
- wherein Tex is exhaust temperature, Pto is the pressure at an output of the turbine, ma is mass flow to the compressor, cp is specific heat, Ta is atmospheric temperature, a1 through a6 are constants, Prc is the calculated pressure ratio across the compressor, and Qc is the calculated compressor flow;
- calculating a turbine flow from the equation:
- Qt=b1±b2Ec±b3Ec2±b4Ej
- wherein Ej is inertial power and Ec is calculated compressor power;
- and
- commanding the turbocharger to operate at the calculated turbine flow.
A method of calculating a boost pressure command for a turbocharger having a turbine operatively connected to an exhaust of an internal combustion engine and having a compressor operatively connected to an intake of the engine, the method comprising:
- monitoring a charge flow command, mc;
- monitoring a temperature at the intake, Ti;
- calculating an exhaust gas recirculation fraction, EGRf;
- calculating the boost pressure command for the compressor from the equation:
- P
- i
- =
- 2
- ·
- R
- ·
- T
- i
- ·
- m
- .
- c
- n
- ·
- D
- ·
- η
-
- (
- EGRf
- ,
- n
- )
- wherein R is the ideal gas constant, n is rotational speed of the engine, D is engine displacement, and η is engine volumetric efficiency calculated as a function the exhaust gas recirculation fraction and the rotational speed of the engine.
Dependencies are inferred from the claim text.