Method to control in any possible operating point the combustion of a compression ignition internal combustion engine with reactivity control through the fuel injection temperature

A method to control the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• varying the injection temperature (T) as a function of the load of the internal combustion engine (1) and/or as a function of the rotation speed of the internal combustion engine (1) between a maximum injection temperature (TMAX) and a minimum injection temperature (Tmin) lower than the maximum injection temperature (TMAX);
• wherein the second supplying system comprises:
• a first common rail (15H) for containing the fuel;
• a first heating device (13) for heating the fuel inside the first common rail (15H) at the maximum injection temperature (TMAX);
• a second common rail (15C) for containing the fuel and separated from the first common rail (15H);
• and
• a second heating device (13) for heating the fuel inside the second common rail (15C) at the minimum injection temperature (Tmin).

A method to control in any possible operating point the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• determining the operating point constituted by a load and by a rotation speed of the internal combustion engine (1);
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• reducing the injection temperature (T) when the load increases and/or when the rotation speed of the internal combustion engine (1) increases;
• wherein, when the internal combustion engine (1) works with a low load, in particular when the indicated mean pressure is below 4 bar, and when the air inside the cylinder (2) at the closing of the intake valve (4) is not heated at a temperature of at least 70° C.:
• the injection temperature (T) is equal to at least 500° C.;
• and/or the second fraction (F2) of the fuel quantity (Q) comprises at least 70% of the fuel quantity (Q) and can temporarily reach 100% of the fuel quantity (Q).

A method to control in any possible operating point the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• determining the operating point constituted by a load and by a rotation speed of the internal combustion engine (1);
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• reducing the injection temperature (T) when the load increases and/or when the rotation speed of the internal combustion engine (1) increases;
• wherein, when the internal combustion engine (1) works with a low load, in particular when the indicated mean pressure is below 4 bar, it is provided the further step of heating at a temperature of at least 70° C. the air inside the cylinder (2) at the closing of the intake valve (4).

A method to control in any possible operating point the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• determining the operating point constituted by a load and by a rotation speed of the internal combustion engine (1);
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• reducing the injection temperature (T) when the load increases and/or when the rotation speed of the internal combustion engine (1) increases;
• wherein when the internal combustion engine (1) works with a medium load, in particular when the indicated mean pressure ranges from 4 to 11 bar:
• the injection temperature (T) is comprised between 350° C. and 500° C.;
• and/or the second fraction (F2) of the fuel quantity (Q) is comprised between 5% and 25% of the fuel quantity (Q).

A method to control in any possible operating point the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• determining the operating point constituted by a load and by a rotation speed of the internal combustion engine (1);
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• reducing the injection temperature (T) when the load increases and/or when the rotation speed of the internal combustion engine (1) increases;
• wherein when the internal combustion engine (1) works with a high load, in particular when the indicated mean pressure is higher than 11 bar, the injection temperature (T) is comprised between 200° C. and 350° C.;
• and/or the second fraction (F2) of the fuel quantity (Q) is comprised between 3% and 10% of the fuel quantity (Q).

A method to control in any possible operating point the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• determining the operating point constituted by a load and by a rotation speed of the internal combustion engine (1);
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• reducing the injection temperature (T) when the load increases and/or when the rotation speed of the internal combustion engine (1) increases;
• wherein when the internal combustion engine (1) works with a high load, in particular when the indicated mean pressure is higher than 11 bar, the angular distance from the top dead centre (PMS) of the beginning of the injection of the second fraction (F2) ranges from 30° to 60°.

The method to control in any possible operating point the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• determining the operating point constituted by a load and by a rotation speed of the internal combustion engine (1);
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• reducing the injection temperature (T) when the load increases and/or when the rotation speed of the internal combustion engine (1) increases;
• wherein when the internal combustion engine (1) works with a high load, in particular when the indicated mean pressure is higher than 11 bar, at least part of the first fraction (F1) of the fuel quantity (Q) is injected by the first injector (11) within 60° from the top dead centre (PMS).

The method to control in any possible operating point the combustion of a compression ignition internal combustion engine (1);

• the internal combustion engine (1) is provided with at least one piston (7), which slides, with a reciprocating motion, on the inside of a cylinder (2), so as to carry out a succession of combustion cycles, each comprising at least an intake stroke and a compression stroke;
• the control method comprises the steps of:
• determining the operating point constituted by a load and by a rotation speed of the internal combustion engine (1);
• establishing, for each combustion cycle, a fuel quantity (Q) to be injected into the cylinder (2);
• injecting a first fraction of the fuel quantity (Q) at least partially during the intake and/or compression stroke by means of a first fuel injector (9;
• 11), which receives the fuel from a first supplying system without active heating devices, so that the first fraction (F1) of the fuel quantity (Q) has a temperature that is lower than an injection temperature (T) higher than 100° C.;
• heating a second fraction (F2) of the fuel quantity (Q), which is equal to the remaining fraction of the fuel quantity (Q), at the injection temperature (T);
• injecting the second fraction (F2) of the fuel quantity (Q) heated at the injection temperature (T) into the cylinder (2) at the end of the compression stroke and at no more than 60° from the top dead centre (PMS) by means of a second fuel injector (8), which is different from and independent of the first fuel injector (9;
• 11), directly injects into the cylinder (2), and receives the fuel from a second supplying system, which is at least partially separate from and independent of the first supplying system and is provided with at least one active heating device (12;
• 13), which is controlled so as to cause the fuel to have the injection temperature (T);
• and
• reducing the injection temperature (T) when the load increases and/or when the rotation speed of the internal combustion engine (1) increases;
• wherein when the internal combustion engine (1) works with a high load, in particular when the indicated mean pressure is higher than 11 bar, the angular distance from the top dead centre (PMS) of the beginning of the injection of the second fraction (F2) is smaller than 40°.