System and method for modeling of turbo-charged engines and indirect measurement of turbine and waste-gate flow and turbine efficiency

A method for calculating a real-time estimated turbine pressure ratio (PrT) exhaust state in an internal combustion engine system having a turbo-charger with a compressor and an exhaust driven turbine, comprising the steps of:

• providing a controller in electrical connection to the engine and configured to calculate the real-time estimated turbine pressure ratio (PrT) exhaust state, and the controller including a first mathematical model stored in a memory in the engine and having a corrected turbine mass flow rate ({dot over (m)}T,cor) in mathematical relationship to a turbine pressure ratio (PrT), and a second mathematical model stored in the memory in the engine having a product term (A*B), said product term (A*B) including a turbine power term (A) containing a determined power level (Pc) and a turbine boundary term (B) containing a turbine outlet pressure (PT,out), and the product term (A*B) being in mathematical relation to a corrected turbine mass flow rate ({dot over (m)}T,cor);
• measuring intake parameter values of the engine with the controller;
• determining the power level (Pc) absorbed by the compressor with the controller using predetermined compressor characteristics data and the measured intake parameter values;
• determining a value for the product term (A*B) with the controller using the determined power level (Pc);
• determining a value for the corrected turbine mass flow rate ({dot over (m)}T,cor) with the controller using the second mathematical model and the determined value for the product term (A*B);
• and
• determining a value for the turbine pressure ratio (PrT) with the controller using the first mathematical model using the determined corrected turbine mass flow rate ({dot over (m)}T,cor) value, wherein the real-time estimated turbine pressure ratio (PrT) exhaust state is used to control operating performance of the internal combustion engine.

A method for indirect measurement of a turbine mass flow rate ({dot over (m)}T) in an internal combustion engine system having a turbo-charger with a compressor and an exhaust driven turbine with a waste-gate flow path that bypasses the turbine in a parallel path, comprising the steps of:

• providing an off-line controller configured to determine the turbine mass flow rate ({dot over (m)}T);
• measuring turbine operating parameters for a plurality of engine system operating conditions in the engine system, said measured turbine operating parameters including a turbine inlet pressure (PT,in), a turbine outlet pressure (PT,out), a turbine inlet temperature (TT,in) and an engine mass flow rate ({dot over (m)}eng);
• determining a corrected turbine mass flow rate ({dot over (m)}T,cor) values for a selected turbine pressure ratio (PrT) with the off-line controller using the measured turbine operating parameters in a mathematical model stored in a memory and accessed by off-line controller where a turbine pressure ratio (PrT) is in mathematical relation to a corrected turbine mass flow rate ({dot over (m)}T,cor);
• converting the corrected turbine mass flow rate ({dot over (m)}T,cor) values to the turbine mass flow rate ({dot over (m)}T) values as a function of turbine outlet pressure (PT,out) and turbine inlet temperature TT,in with the off-line controller;
• measuring PT,in, PT,out, PT,in, and {dot over (m)}eng for a plurality of engine system operating conditions in the engine system;
• generating a first set of data-pairs for turbine pressure ratio (PrT) and corrected engine mass flow rate ({dot over (m)}eng,cor) using the measured test data with the off-line controller;
• generating a second set of data-pairs for turbine pressure ratio (PrT) and corrected turbine mass flow rate ({dot over (m)}T,cor) from the first set of data pairs with the off-line controller, wherein the second set of data-pairs comprise the waste-gate valve being closed;
• and
• populating said second set of data-pairs in a data table in a memory disposed in the internal combustion engine, and the internal combustion engine includes an engine controller in electrical connection to the engine, and the engine controller accesses the data table having said second set of data-pairs to determine a real-time estimated exhaust state in the internal combustion engine.

A method for indirect measurement of an isentropic efficiency of a turbine ηT of an internal combustion engine system having a turbo-charger with a compressor and an exhaust driven turbine with a waste-gate flow path that bypasses the turbine in a parallel path, comprising the steps of:

• providing a first controller configured to characterize the isentropic efficiency of the turbine (ηT) for the engine system for a plurality of engine system operating conditions;
• measuring operating parameters for the plurality of engine system operating conditions associated with the engine system, said operating parameters including a compressor inlet temperature (TC,in), a compressor inlet pressure (PC,in), a compressor outlet pressure (PC,out), turbine inlet pressure (PT,in), a turbine outlet pressure (PT,out), a turbine inlet temperature (TT,in) and a compressor mass flow rate ({dot over (m)}C);
• determining a corrected turbine mass flow rate ({dot over (m)}T,cor) value for a selected turbine pressure ratio (PrT) with the first controller and the first controller using values from the measured operating parameters in a first mathematical model stored in a memory accessed by the first controller to derive the corrected turbine mass flow rate ({dot over (m)}T,cor) and the turbine pressure ratio (PrT), and the first mathematical model including a turbine pressure ratio (PrT and a corrected turbine mass flow rate ({dot over (m)}T,cor), and data in the first mathematical model corresponds to a condition of the waste-gate flow path being closed;
• converting the corrected turbine mass flow rate ({dot over (m)}T,cor) value to a turbine mass flow rate ({dot over (m)}T) value as a function of the turbine outlet pressure (PT,out) and the turbine inlet temperature (TT,in) with the first controller:
• and
• determining values for the turbine isentropic efficiency (ηT) over the plurality of engine system operating conditions with the first controller in accordance with a second mathematical model stored in the memory accessed by the first controller where the second mathematical model includes using a predetermined compressor characteristics map data, the turbine mass flow rate ({dot over (m)}T) value, the turbine pressure ratio (PrT) value, a compressor pressure ratio (Prc) value, the compressor mass flow rate ({dot over (m)}C) value, the compressor inlet temperature (TC,in) value, and the turbine inlet temperature (TT,in);
• and
• populating the determined turbine isentropic efficiency (ηT) values in a data table disposed in the memory of the internal combustion engine, and an engine controller being disposed in, and in electrical connection with the internal combustion engine, and the engine controller having access to the data table such that the turbine isentropic efficiency (ηT) values are used by the engine controller to calculate a real-time estimated exhaust state of the internal combustion engine.