Method to determine the mass of air trapped in each cylinder of an internal combustion engine

A method to determine a mass (m) of air trapped in at least one cylinder of an internal combustion engine;

• wherein the internal combustion engine includes an intake manifold and an exhaust manifold, a piston that is moveably supported in the at least one cylinder such that the piston and the at least one cylinder define a combustion chamber and wherein the at least one cylinder includes an intake valve that opens and closes and an exhaust valve that opens and closes such that the at least one cylinder is in fluid communication with the intake manifold from which the at least one cylinder receives an air/fuel mixture through the intake valve when the intake valve is open, and in fluid communication with the exhaust manifold into which the at last one cylinder introduces exhaust gases produced by combustion through the exhaust valve when the exhaust valve is open;
• wherein each intake of the air/fuel mixture into the at least one cylinder, each combustion of the air/fuel mixture in the combustion chamber and the exhaust gases from the at least one cylinder together define a work cycle and wherein the opening and closing of the intake valve is controlled so as to change the timing of the opening and closing;
• wherein the internal combustion engine is controlled by an electronic control unit which is electrically connected to an intake manifold temperature sensor which senses a temperature of the air/fuel mixture in the intake manifold and is electrically connected to an intake manifold pressure sensor that senses a pressure of the air/fuel mixture present in the intake manifold and electrically connected to a rotational speed sensor which senses the angular position and, hence, the speed (n) of rotation of the internal combustion engine;
• the method comprises the steps of:
• detecting the pressure of the air/fuel mixture inside the intake manifold using the intake manifold pressure sensor, detecting the speed (n) of rotation of the internal combustion engine using the rotational speed sensor and detecting a closing delay angle (IVC) of the intake valve associated with the at least one cylinder;
• determining a mass of gases produced by the combustion in a previous work cycle and present inside the at least one cylinder;
• determining an inner volume (V) of the cylinder as a function of the speed (n) of rotation of the internal combustion engine and of the closing delay angle (IVC) of the intake valve associated with the at least one cylinder;
• and
• determining the mass of air (m) trapped in the at least one cylinder through a product of a pressure (P) inside the intake manifold by the inner volume (V) of the at least one cylinder, from which the mass of gases is subtracted using a calculation model stored in the electronic control unit;
• wherein the step of determining the mass of gases comprises the sub-steps of:
• calculating a mass (MOVL) of gases which flows, during an overlap phase in which the intake valve and the exhaust valve are simultaneously open, from an exhaust to an intake and which is re-sucked into the at least one cylinder, during the following intake phase, through the respective intake valve associated with the at least one cylinder using the following formula, in which the combustion chamber represents a passage section:
• M
• OVL
• =
• S
• id
• *
• β
• ⁡
• (
• P
• P
• 0
• ,
• n
• )
• *
• P
• 0
• P
• 0
• ⁢
• _
• ⁢
• REF
• *
• T
• 0
• ⁢
• _
• ⁢
• REF
• T
• 0
• *
• 1
• n
• where:
• Sid represents an area of the passage section;
• n represents the speed of rotation (n) of the internal combustion engine;
• P0_REF represents a reference pressure in the exhaust manifold;
• T0_REF represents a reference temperature in the exhaust manifold;
• T0 represents a temperature in the exhaust manifold;
• P0 represents a pressure in the exhaust manifold;
• P represents the pressure in the intake manifold;
• wherein the area (Sid) of the passage section is calculated as a product between a first function (A) of the speed (n) of rotation of the internal combustion engine and of a duration (OVL) of the overlap phase and a second function of the speed (n) of rotation of the internal combustion engine and of an angular difference between a top dead center (PMS) and a center of gravity of the overlap phase;
• and
• calculating the mass of gases as a function of the mass (MOVL) of gases to determine a quantity of fuel to be injected into said cylinder.

A method to determine a mass (m) of air trapped in at least one cylinder of an internal combustion engine;

• wherein the internal combustion engine includes an intake manifold and an exhaust manifold, a piston that is moveably supported in the at least one cylinder such that the piston and the at least one cylinder define a combustion chamber and wherein the at least one cylinder includes an intake valve that opens and closes and an exhaust valve that opens and closes such that the at least one cylinder is in fluid communication with the intake manifold from which the at least one cylinder receives an air/fuel mixture through the intake valve when the intake valve is open, and in fluid communication with the exhaust manifold into which the at least one cylinder introduces exhaust gases produced by combustion through the exhaust valve when the exhaust valve is open;
• wherein each intake of the air/fuel mixture into the at least one cylinder, each combustion of the air/fuel mixture in the combustion chamber and the exhaust gases from the at least one cylinder together define a work cycle and wherein the opening and closing of the exhaust valve is controlled so as to change the timing of opening and closing the exhaust valve;
• wherein the internal combustion engine is controlled by an electronic control unit which is electrically connected to an intake manifold temperature sensor which senses a temperature of the air/fuel mixture in the intake manifold and is electrically connected to an intake manifold pressure sensor that senses a pressure of the air/fuel mixture present in the intake manifold and electrically connected to a rotational speed sensor which senses the angular position and, hence, the speed (n) of rotation of the internal combustion engine;
• the method comprises the steps of:
• detecting the pressure of the air/fuel mixture inside the intake manifold using the intake manifold pressure sensor, detecting the speed (n) of rotation of the internal combustion engine using the rotational speed sensor and detecting a closing delay angle (IVC) of the intake valve associated with the at least one cylinder;
• determining a mass of gases produced by the combustion in a previous work cycle and present inside the at least one cylinder;
• determining an inner volume (V) of the at least one cylinder as a function of the speed (n) of rotation of the internal combustion engine and of the closing delay angle (IVC) of the intake valve associated with the at least one cylinder;
• and
• determining the mass of air (m) trapped in the at least one cylinder through a product of a pressure (P) inside the intake manifold by the inner volume (V) of the at least one cylinder, from which the mass of gases is subtracted using a calculation model stored in the electronic control unit;
• wherein the step of determining the mass of gases comprises the sub-steps of:
• calculating a mass (MOVL) of gases which flows, during an overlap phase in which the intake valve and the exhaust valve are simultaneously open, from an exhaust to an intake and which is re-sucked into the at least one cylinder, during the following intake phase, through the intake valve associated with the at least one cylinder using the following formula, in which the combustion chamber of the cylinder represents a passage section:
• M
• OVL
• =
• S
• id
• *
• β
• ⁡
• (
• P
• P
• 0
• ,
• n
• )
• *
• P
• 0
• P
• 0
• ⁢
• _
• ⁢
• REF
• *
• T
• 0
• ⁢
• _
• ⁢
• REF
• T
• 0
• *
• 1
• n
• where:
• Sid represents an area of the passage section;
• n represents the speed of rotation (n) of the internal combustion engine;
• P0_REF represents a reference pressure in the exhaust manifold;
• T0_REF represents a reference temperature in the exhaust manifold;
• T0 represents a temperature in the exhaust manifold;
• P0 represents a pressure in the exhaust manifold;
• P represents the pressure in the intake manifold;
• wherein the area (Sid) of the passage section is calculated as a product between a first function (A) of the speed (n) of rotation of the internal combustion engine and of a duration (OVL) of the overlap phase and a second function of the speed (n) of rotation of the internal combustion engine and of an angular difference between a top dead center (PMS) and a center of gravity of the overlap phase;
• and
• calculating the mass of gases as a function of the mass (MOVL) of gases to determine a quantity of fuel to be injected into the at least one cylinder.

A method to determine a mass (m) of air trapped in at least one cylinder of an internal combustion engine;

• wherein the internal combustion engine includes an intake manifold and an exhaust manifold, a piston that is moveably supported in the at least one cylinder such that the piston and the at least one cylinder define a combustion chamber and wherein the at least one cylinder includes an intake valve that opens and closes and an exhaust valve that opens and closes such that the at least one cylinder is in fluid communication with the intake manifold from which the at least one cylinder receives an air/fuel mixture through the intake valve when the intake valve is open, and in fluid communication with the exhaust manifold into which the at least one cylinder introduces exhaust gases produced by combustion through the exhaust valve when the exhaust valve is open;
• wherein each intake of the air/fuel mixture into the at least one cylinder, each combustion of the air/fuel mixture in the combustion chamber and the exhaust gases from the at least one cylinder together define a work cycle and wherein the opening and closing of the intake valve and/or of the exhaust valve are controlled so as to change the timing of their respective opening and closing;
• wherein the internal combustion engine is controlled by an electronic control unit which is electrically connected to an intake manifold temperature sensor which senses a temperature of the air/fuel mixture in the intake manifold and is electrically connected to an intake manifold pressure sensor that senses a pressure of the air/fuel mixture present in the intake manifold and electrically connected to a rotational speed sensor which senses the angular position and, hence, the speed (n) of rotation of the internal combustion engine;
• the method comprises the steps of:
• detecting a pressure of the air/fuel mixture inside the intake manifold using the intake manifold pressure sensor, detecting the speed (n) of rotation of the internal combustion engine using the rotational speed sensor and detecting a closing delay angle (IVC) of the intake valve associated with the at least one cylinder;
• determining a mass of gases produced by the combustion in a previous work cycle and present inside the at least one cylinder;
• determining an inner volume (V) of the at least one cylinder as a function of the speed (n) of rotation of the internal combustion engine and of the closing delay angle (IVC) of the intake valve associated with the at least one cylinder;
• and
• determining the mass of air (m) trapped in the at least one cylinder through a product of a pressure (P) inside the intake manifold by the inner volume (V) of the at least one cylinder, from which the mass of gases is subtracted using a calculation model stored in the electronic control unit;
• wherein the step of determining the mass of gases comprises the sub-steps of:
• calculating a mass (MOVL) of gases which flows, during an overlap phase in which the intake valve and the exhaust valve are simultaneously open, from an exhaust to an intake and which is re-sucked into the at least one cylinder, during the following intake phase, through the intake valve associated with the at least one cylinder using the following formula, in which the combustion chamber of the at least one cylinder represents a passage section:
• M
• OVL
• =
• S
• id
• *
• β
• ⁡
• (
• P
• P
• EXH
• ,
• n
• )
• *
• P
• EXH
• P
• 0
• ⁢
• _
• ⁢
• REF
• *
• T
• 0
• ⁢
• _
• ⁢
• REF
• T
• EXH
• *
• 1
• n
• where:
• Sid represents an area of the passage section;
• n represents the speed of rotation (n) of the internal combustion engine;
• P0_REF represents a reference pressure in the exhaust manifold;
• T0_REF represents a reference temperature in the exhaust manifold;
• TEXH represents a temperature of a gas flow in the exhaust manifold;
• PEXH represents a pressure of a gas flow in the exhaust manifold;
• P represents the pressure in the intake manifold;
• wherein the area (Sid) of the passage section is calculated as a product between a first function (A) of the speed (n) of rotation of the internal combustion engine and of a duration (OVL) of the overlap phase and a second function of the speed (n) of rotation of the internal combustion engine and of an angular difference between a top dead center (PMS) and a center of gravity of the overlap phase;
• and
• calculating the mass of gases as a function of the mass (MOVL) of gases to determine a quantity of fuel to be injected into the at least one cylinder.