Method for estimating and controlling intake efficiency of internal combustion engine

Abstract

To determine the mass of air trapped in each cylinder of an internal combustion engine.SOLUTION: At least one intake valve 5 is driven to vary the lift of the intake valve 5 in a controlled manner. On the basis of a filling model using measured and / or estimated physical quantities, a value for each quantity of a first group of reference quantities, which at least include: an intake pressure P measured inside an intake manifold 4; an engine rotation speed; and the mass of gases (OFF) produced by combustion in a previous operating cycle and present in a cylinder 2, which is estimated as a function of the lift H and of a closing delay angle of the intake valve depending on the lift H, is determined. On the basis of the filling model, an actual inner volume of each cylinder 2 is determined as a function of the engine rotation speed, of the lift H of the intake valve and of the closing delay angle of the intake valve. On the basis of the above quantities, the mass m of air trapped in each cylinder 2 is determined as a function of the first group of reference quantities and of the actual volume in each cylinder 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for estimating and controlling the intake efficiency of an internal combustion engine, implemented by an electronic process.

[0002] In particular, the present invention relates to a method for determining the mass of air trapped in each cylinder of an internal combustion engine, and to a method for controlling and executing the operation of at least one cylinder of an internal combustion engine. [Background technology]

[0003] As is well known, an internal combustion engine that is turbocharged includes a plurality of fuel injectors that inject fuel into respective cylinders, each of which is coupled to an intake manifold through at least one corresponding intake valve and to an exhaust manifold through at least one corresponding exhaust valve.

[0004] The intake manifold receives a gas mixture including both exhaust gases and fresh air, i.e., air from the outside environment through an intake duct fitted with an air cleaner for fresh air flow and regulated by a throttle valve, and an air flow meter is positioned along the intake duct, preferably downstream of the air cleaner.

[0005] An air flow meter is a sensor connected to an electronic control unit and designed to detect the flow rate of fresh air taken into an internal combustion engine, which is a very important parameter for engine control, in particular for determining the amount of fuel injected into the cylinders to obtain a predetermined air-fuel ratio downstream of the exhaust duct of the exhaust manifold.

[0006] However, air flow meters are generally very expensive and sensitive components that can become contaminated with oil vapor and dust, thereby changing the measured value of the flow rate of fresh air drawn into the internal combustion engine.

[0007] Therefore, there is an increasing need to determine the flow rate of fresh air drawn into an internal combustion engine (i.e., the amount trapped in each cylinder) without using an air flow meter as much as possible, but still maintaining a high degree of accuracy that meets the performance requirements of the relevant technical sector.

[0008] Known solutions in this regard do not satisfy the above-mentioned requirements, particularly in the field of internal combustion engines in which VVH (variable valve height) control technology is used, or in which both VVH and VVT (variable valve timing) technology is used. Summary of the Invention

[0009] The object of the present invention is to provide a method for determining the amount of air trapped in each cylinder of an internal combustion engine, which makes it possible to at least partially overcome the drawbacks mentioned above with respect to the prior art and to address the aforementioned needs particularly felt in the technical sector under consideration.

[0010] Such an object is achieved through a method as set forth in claim 1.

[0011] Further embodiments of the method are defined in claims 2 to 35.

[0012] A further object of the invention is a method for controlling and implementing the operation of at least one cylinder of an internal combustion engine according to claim 36 or claim 37. [Brief explanation of the drawings]

[0013] Further characteristics and advantages of the method according to the invention will become apparent from the following description which describes preferred embodiments, given as illustrative and non-limiting examples, with reference to the attached drawings, in which:

[0014] [Figure 1] FIG. 1 shows diagrammatically a preferred embodiment of an internal combustion engine provided with an electronic control unit for implementing the method according to the invention. [Figure 2]FIG. 2 shows the cylinder of the engine of FIG. 1 in more detail. [Figure 3] Figure 3 shows the opening and closing rules for the exhaust valve (curve on the left) and intake valve (curve on the right) when using only VVH lift control. [Figure 4] Figure 4 shows the opening and closing rules for the exhaust valve (curve on the left) and intake valve (curve on the right) when using only VVT timing control. [Figure 5] Figure 5 shows the opening and closing rules for the exhaust valve (curve on the left) and intake valve (curve on the right) when using VVH lift control and VVT timing control. [Figure 6] FIG. 6 shows diagrammatically the intake and exhaust valve overlap steps of the engine of FIG. [Figure 7] FIG. 7 shows the known law of the tendency of the compression factor of an isentropic flow through an opening of radius r as a function of the relationship between the pressure across the opening. DETAILED DESCRIPTION OF THE INVENTION

[0015] Before describing the method, an example of an engine 1 on which the method according to the invention can be used will now be described, diagrammatically and simplified for clarity of explanation, with reference to FIGS. 1 and 2.

[0016] The engine 1 is an internal combustion engine.

[0017] Such an engine 1 is preferably an internal combustion engine supercharged by a turbocharger supercharging system.

[0018] The engine 1 comprises a number of fuel injectors which inject fuel into each of the cylinders 2 (preferably four cylinders arranged in series). Typically, a corresponding fuel injector is provided for each cylinder 2. Each of the cylinders 2 is connected to an intake manifold 4 through at least one respective intake valve 5 and to an exhaust manifold 6 through at least one respective exhaust valve 7. According to several possible embodiments, the fuel injectors may be of the indirect type (each fuel injector is arranged upstream of the respective cylinder, in the intake pipe connecting the intake manifold to the cylinder) or of the direct type (each fuel injector is arranged partly within the cylinder).

[0019] Each cylinder 2 has a respective piston 3 mechanically connected to a drive shaft 11 via a connecting rod (in a manner known per se) for transmitting the force generated by combustion in the cylinder 3 to the drive shaft 11.

[0020] The intake manifold 4 receives a gas mixture including both exhaust gases and fresh air conditioned by a throttle valve 12 coming from the outside environment through an intake duct 8. The intake duct 8 is preferably provided with an air cleaner for the flow of fresh air. The throttle valve 12 is preferably movable between a closed position and a maximum open position. In the solution described herein, no air flow meter is provided along the intake line 8.

[0021] The position of each exhaust valve 7 and each intake valve 5 is controlled by a respective camshaft, which is acted upon by a drive shaft 11, for example.

[0022] An intercooler is preferably arranged along the intake duct 8. The intercooler may be integrated into the intake manifold 4 and serves to cool the intake air. An exhaust duct 9 is connected to the exhaust manifold 6 and delivers the exhaust gases produced by the combustion to an exhaust system which discharges the gases produced by the combustion to the atmosphere. The exhaust system typically includes a catalytic converter and a downstream muffler.

[0023] The supercharging system of the internal combustion engine 1 comprises a turbocharger provided with a turbine and a compressor. The turbine is arranged along the exhaust pipe 9 so as to rotate at high speed under the bias of the exhaust gases discharged from the cylinder 3. The compressor is arranged along the intake duct 8 and is mechanically linked to the turbine, and is rotatably powered by the turbine itself, increasing the air pressure in the intake duct 8.

[0024] In the above, reference has been made to an internal combustion engine 1 which is supercharged via a turbocharger. Alternatively, the method of the invention can be suitably used in any internal combustion engine. According to another embodiment, the method can be applied to internal combustion engines which are supercharged via a dynamic or positive displacement compressor.

[0025] A variable valve height (VVH) control is implemented in the internal combustion engine 1 considered here.

[0026] Such VVH control is performed through a VVH device or VVH actuator, which is known per se (for example of the META or Valvetronic type, referring to solutions well known to those skilled in the industry), and which is symbolically represented as a block in Figure 2 by reference numeral 50.

[0027] The VVH actuator allows the intake valve lift law to be continuously varied. In general, all possible lift values ​​H (which can be set by the VVH actuator) also represent values ​​corresponding to an early opening and a late closing of the intake valve.

[0028] As will be shown in more detail below, the VVH actuator comprises an intake valve lift adjuster that can change the lift law, for example starting from a maximum lift profile and decreasing the lift H and width to determine a different profile, i.e., delaying the opening of the intake valve and advancing its closing. In general, variable speed actuation of the valve lift works through specific mechanical / geometric characteristics and has a degree of freedom γ corresponding to the position of the variable speed actuation / actuator, which has a one-to-one relationship with the lift H(γ).

[0029] The internal combustion engine 1 is controlled by an electronic control unit 10, which manages the operation of all components of the internal combustion engine 1. In particular, the electronic control unit 10 is connected to a number of sensors, such as sensors measuring the temperature and pressure along the intake duct 8 upstream of the compressor, sensors measuring the temperature and pressure along the intake duct 8 upstream of the throttle valve 12, and sensors measuring the temperature T and pressure P of the gas mixture present in the intake manifold 4.

[0030] Furthermore, the electronic control unit 10 may be connected to a sensor that measures the angular position of the drive shaft 11 and thus the rotational speed n of the engine (ie the number of revolutions per minute (rpm) of the engine).

[0031] Additionally, the electronic control unit 10 may be connected to sensors that measure the air-fuel ratio of the exhaust gases upstream of the catalytic converter (e.g., a linear oxygen probe such as a UHEGO or UEGO, which are well known and will not be described in detail herein), and sensors that measure intake valve phase and / or exhaust valve phase.

[0032] Some of the aforementioned sensors are illustrated in Figure 2 as black circles, each named after the variable they can sense.

[0033] The aforementioned "charge model" or calculation model is stored in the electronic control unit 10. Through said model, inter alia, the mass m of air trapped in each cylinder 2 and the mass M of air taken into the internal combustion engine 1 are calculated. TOT is required.

[0034] As described above, the electronic control unit 10 controls all actuators of all engine cylinders (for example, the blocks designated by reference numerals 50, 51, and 52 in FIG. 2) and all sensors (for example, the blocks designated by reference numerals P, T, VVti, VVte, H, and T EXH , P EXH It is worth noting that the blocks are operatively connected to the blocks shown in Figure 2 by (a) and (b). In Figures 1 and 2, explicit connections are not shown and have been omitted for clarity in describing other aspects.

[0035] 1 to 7, a method for determining the amount of air m trapped in each cylinder 2 of an internal combustion engine 1 having a number of cylinders 2 will be described. Each cylinder 2 is connected to an intake manifold 4 and an exhaust manifold 6, and receives fresh air from the intake manifold 4 through at least one respective intake valve 5, and directs exhaust gases produced by combustion into the exhaust manifold 6 through at least one respective exhaust valve 7. At least one intake valve 5 is operated to controllably vary the lift H of the intake valve 5.

[0036] The method includes first determining a value for each of a first group of reference quantities based on a filling model that uses measured and / or estimated physical quantities.

[0037] Such a first group of reference quantities includes the amount of gas (OFF) produced by combustion in the previous operating cycle and present in cylinder 2, estimated depending on the intake pressure P measured inside the intake manifold 4; the engine rotation speed n; the aforementioned lift H, and the intake valve closing retard IVC based on the aforementioned lift H.

[0038] The method provides for determining the actual internal volume V of each cylinder 2 as a function of the engine speed n, the aforementioned lift H of the intake valves, and the aforementioned closing retard IVC of the intake valves, based on the aforementioned charging model.

[0039] The method ultimately leads to determining the mass m of air trapped in each cylinder 2 as a function of the first group of reference quantities and the actual volume V inside each cylinder 2 through the following relations:

[0040]

number

[0041] According to a preferred embodiment, the aforementioned “charge model” or calculation model, which makes it possible, inter alia, to determine the mass m of air trapped in each cylinder 2 , is stored in the electronic control unit 10 .

[0042] According to an embodiment (shown in the diagram described in FIG. 3 ), the method further comprises operating the intake valve 5 using an intake valve lift adjuster 50 by controlling and varying the intake valve lift law so as to define both the lift H and the intake valve opening advance angle IVO and the intake valve closing retard angle IVC with one degree of freedom γ.

[0043] According to an example embodiment of this invention, the operating step includes determining the intake valve opening advance IVO using the following relationship:

[0044]

number

[0045] Here, IVO hmax is the maximum lift (H in Figure 3) max Δivo(H) is the variation of intake valve opening advance based on control lift (H).

[0046] Furthermore, the operating step includes determining intake valve closing retard IVC using the following relationship:

[0047]

number

[0048] Here, IVC hmax is the maximum lift H max Δivc(H) is the variation of the intake valve closing retard based on the control lift (H).

[0049] Furthermore, the aforementioned quantities determined by the lift H (IVO(H), IVC(H), Δivo(H), Δivc(H)) are also determined by the aforementioned degree of freedom γ, because, as mentioned above, H is determined by γ.

[0050] In FIG. 3, the symbols "bdc" and "tdc" indicate bottom dead center and top dead center, respectively.

[0051] According to an embodiment, the degree of freedom γ relates to the position of the VVH actuator.

[0052] According to an embodiment, the method is applied to an internal combustion engine 1 in which variable valve timing (VVT) control is also implemented. Thus, the present embodiment operates in the presence of both VVH and VVT control.

[0053] In such cases, the intake valves 5 and / or exhaust valves 7 are operated by a VVT device, or VVT actuator, or VVT phaser, which, for example, hydraulically acts on the shaft that operates the intake valves 5 and / or exhaust valves 7 to modify their timing relative to the drive shaft.

[0054] Specifically, according to the method embodiments discussed herein, at least one intake valve 5 is further operated to controllably vary the intake valve angular displacement VVTi and / or at least one exhaust valve 7 is operated to controllably vary the exhaust valve angular displacement VVTe.

[0055] The step of determining values ​​for the first group of reference quantities includes determining an intake valve closing retard IVC based on both the intake valve lift H and the intake valve displacement VVTi.

[0056] As used herein, the term "VVTi intake valve displacement (or displacement angle)" is used to indicate the angular amplitude of deviation equal to the angular position variation of the VVTi intake actuator relative to the engine (crank) angle relative to a reference value for the intake valve corresponding to zero VVTi.

[0057] Similarly, the term "VVTe exhaust valve displacement (or displacement angle)" is used to indicate the angular amplitude of deviation equal to the angular position variation of the VVTe exhaust actuator relative to the engine (crank) angle, relative to a reference value for the exhaust valve corresponding to zero VVTe.

[0058] As stated above, displacement therefore refers to the variation in the position of the VVT ​​actuator.

[0059] According to an example embodiment, the method further includes operating the intake valve 5 using an intake valve phaser 51 by controlling and varying the intake valve displacement VVTi, whereby both the intake valve opening advance angle IVO and the intake valve closing retard angle IVC depend not only on the lift H but also on the intake valve displacement VVTi. The method also includes operating the exhaust valve 7 using an exhaust valve phaser 52 by controlling and varying the VVTe exhaust valve displacement, whereby both the exhaust valve opening advance angle EVO and the exhaust valve closing retard angle EVC depend on the exhaust valve timing displacement VVTe.

[0060] More specifically, the operating step includes determining the intake valve opening advance IVO using the following relationship:

[0061]

number

[0062] Here, IVO ref is the reference value of intake valve opening advance when there is no phase adjustment. VVTi is the reference value IVO ref is the displacement angle of the intake valve phase adjuster 51 relative to each reference position corresponding to

[0063] The operating step further includes determining an intake valve closing retard IVC using the following relationship:

[0064]

number

[0065] Here, IVC ref is the reference value for the intake valve closing retard in the absence of phase adjustment.

[0066] The operating step further includes determining the exhaust intake valve opening retard EVO via the following relationship:

[0067]

number

[0068] Here, EVO ref is the reference value of the exhaust valve opening advance when there is no phase adjustment. VVTe is the reference value EVO ref is the displacement angle of the exhaust valve phaser 52 relative to each reference position indicated by

[0069] The operating step further includes determining exhaust valve closing retard EVC using the following relationship:

[0070]

number

[0071] Here, EVC ref is the reference value of the exhaust valve closing retard without phase adjustment.

[0072] Since the VVT ​​control varies the timing of the intake valve 5 and the overlap with the exhaust valve 7 (the overlap step is the step during which the intake valve 5 and the exhaust valve 7 are simultaneously open), the charging model also comprises information of the aforementioned parameters. Such parameters (shown in Figure 4 for top dead center TDC and bottom dead center BDC) are given by: IVCref: reference closing angle of exhaust valve 5; IVOref: Reference opening angle of intake valve 5; EVCref: reference closing angle of exhaust valve 7; EVOref: Reference opening angle of exhaust valve 7; IVC closing retardation of intake valve 5; Intake valve 5 IVO opening advance; EVC closing retardation of exhaust valve 7; EVO opening advance of exhaust valve 7; It can be summarized as follows.

[0073] As previously mentioned, the displacement angles VVTi and VVTe can also be defined as follows: VVTi: the angular width of the opening / closing deviation of the intake valve 5 relative to the reference value, which is equal to the phase fluctuation of the intake actuator VVT; VVTe: Angle width of opening / closing deviation of exhaust valve 7 from the reference value, which is equal to the phase fluctuation of exhaust actuator VVT.

[0074] The combined operation of VVT and VVH control and each parameter are shown in Figure 5.

[0075] Considering the step of determining the actual internal volume V of cylinder 2, it is worth noting that this volume V can vary geometrically as a function of the intake valve closing retard IVC: V = f(IVC). In fact, the actual internal volume V of cylinder 2 is calculated by multiplying the combustion chamber volume V of cylinder 3 by the cc and the volume V swept by each piston 3 until the closing of each intake valve 5 (i.e., the crank angle relative to the top dead center PMS). c is given by the sum of

[0076] The law of motion used to calculate the effective internal volume V of cylinder 2 at crank angle α, without providing further details (as it is well known in the literature), is as follows: V(α)=V cc +V c (α). This equation becomes as follows when Vc(α) is clarified:

[0077]

number

[0078] Here, V is the actual internal volume of the cylinder. cc is the volume of the combustion chamber of the cylinder. α is the angle of rotation of the crank relative to top dead center PMS. r is the crank radius. L is the length of the connecting rod. S is the area of ​​the piston. d is the offset between the axis of the cylinder and the axis of rotation of the drive shaft. λ denotes the ratio r / L. δ denotes the ratio d / L.

[0079] In general, the volume used in cylinder filling calculations is a function of intake valve closing retard (IVC), intake valve lift (H), engine speed (n), and intake pressure (P).

[0080] Based on experiments and calculations, the applicant has identified the following ways of expressing the above-mentioned dependencies in a more efficient way (the ones defined above are very rough and not very useful in practice) that constitute a good approximation and allow the model to be more easily calibrated.

[0081] According to an embodiment of the method, the step of determining the actual internal volume V of each cylinder includes: v (IVC,n), second map f h (H,n) and the third map f p (P, n) to calculate the actual volume V of each cylinder 2.

[0082] 1st map f v (IVC,n) is a function of intake valve closing retardation IVC and engine speed n.

[0083] 2nd map f h (H,n) is a function of intake valve lift H and engine speed n.

[0084] 3rd map f p (P,n) is a function of intake pressure P and engine speed n.

[0085] According to a more specific embodiment, the actual internal volume V of each cylinder 2 is calculated according to the following relationship:

[0086]

number

[0087] It should be noted that, according to an embodiment, the actual volume V (which may also be defined as the "effective volume V") includes a dimensional constant that is calculated and used in the method, resulting in a product P*V that corresponds dimensionally to the mass. That is, the actual volume V is expressed in units of volume (e.g., cm 3 ) and a dimensional constant. This value is consistently taken into account in all used formulas.

[0088] A further possible refinement of the calculation of the amount of air trapped in the cylinder is considered, which also takes into account temperature parameters.

[0089] According to an embodiment of the method, the aforementioned first group of reference quantities further comprises the temperature T detected in the intake manifold 4 and the temperature T of the engine coolant. H2O Includes.

[0090] The step of determining the amount of air m trapped in each cylinder 2 includes calculating the amount of air m trapped in each cylinder 2 as a function of the first group of reference quantities and the actual volume V in each cylinder 2 via the following equation:

[0091]

number

[0092] where f1(T,P) and f2(T H2O , P) is a well-known function that belongs to the packing model mentioned above.

[0093] The above-described embodiment is based on the following idea: The filling model starts from the well-known ideal gas law and leads to the following equation:

[0094]

number

[0095] where P is the average pressure measured in the intake manifold over the engine cycle; T is the temperature of the fresh air and / or exhaust gas mixture in the intake manifold 4; R is the gas constant, which is equal to 287 [J / kg*K] for an ideal gas; and V is the internal volume of the cylinder when the respective intake valves 5 and exhaust valves 7 are closed.

[0096] The ideal gas law [Equation 11] states that the amount of air m trapped in each cylinder 2 during each cycle is m = P * V * f1(T,P) * f2(T H2O The charge model has been experimentally fitted by incorporating a constant R for the fresh air and / or exhaust gas mixture, expressed as (T,P), where T H2O is the temperature of engine 1, i.e., the temperature of the coolant of engine 1.

[0097] The ideal gas law is further adapted experimentally to the charge model so that the calculation of the amount of air m trapped in each cylinder 2 in each cycle (because it did not leave cylinder 3 itself or was drawn back into the cylinder) takes into account the gases present in the cylinder produced by combustion in the previous operating cycle. Thus, we obtain the above equation

[10] , where OFF is a variable (mass) that takes into account the gases present in cylinder 2 produced by combustion in the previous operating cycle.

[0098] The experiment was performed at temperatures T and T to calibrate the filling model. H2O For example, the reference temperature T may be selected as 40° C., and T H2O may be chosen as 90° C. At such a reference temperature (used for calibration), the above functions f1 and f2 assume a value of 1.

[0099] Described below are method embodiments applicable to engines capable of operating under internal exhaust gas recirculation (EGRi) and / or scavenging conditions. Such operating conditions are known, as are devices and features (not further described herein) that enable internal combustion engines to operate under such conditions.

[0100] It must be taken into account that at the beginning of the intake phase of every engine cycle, residual burnt gases from the previous engine cycle are also present in cylinder 2.

[0101] Geometrically, the volume occupied by residual burned gases from the previous engine cycle, or "dead volume," can be expressed as the sum of the nominal geometric volume of the cylinder combustion chamber and the volume Vc swept by each piston in the cylinder.

[0102] This "dead volume" is a kind of "actual combustion chamber volume", and for convenience, it will be referred to as "combustion chamber volume V cc From a geometrical point of view, such a volume can be related to the angle of rotation α of the crank using the above equation [Equation 8].

[0103] Volume V of the stroke of piston 3 in cylinder 2 c can vary and be accounted for through the parameter TVC, which is explained in more detail below, depending on the different operating conditions assumed.

[0104] Specifically, according to different conceivable variants, the volume V swept by the piston in the cylinder c teeth, If the intake valve 5 opens after the exhaust valve 7 closes, the volume swept by the piston at the moment the exhaust valve 7 closes, or If the exhaust valve 7 closes after the intake valve 5 opens, the volume of the piston stroke at the moment the intake valve 5 opens, or If the moment when the intake valve 5 opens comes before the top dead center PMS, the volume of the stroke by the piston at the top dead center PMS (in this case, the volume Vc of the stroke by the piston in the cylinder is zero, and the actual volume V of the cylinder is the volume V of the combustion chamber of the cylinder. CC corresponds exactly to

[0105] Considering the above assumed cases, the parameter TVC can alternatively correspond to different values ​​(different angles) as described below.

[0106] According to an embodiment applicable when the engine 1 operates in an internal exhaust gas recirculation state EGRi, the method comprises: e (TVC,n), the fifth map ge(OVL,n), and the sixth map he(H,n), the combustion chamber V of cylinder 2 is calculated. cc (i.e., the volume V occupied by the residual combustion gases from the previous engine cycle) cc ) and a fourth map f e (TVC,n) is a function of the first TVC parameter and the engine speed n. The fifth map ge(OVL,n) is a function of the second parameter OVL and the engine speed n. The sixth map he(H,n) is a function of the lift H and the engine speed n.

[0107] The aforementioned first parameter TVC is equal to the exhaust valve 7 closing retard EVC, or alternatively equal to the maximum value between zero and the minimum value of the exhaust valve 7 closing retard EVC and the intake valve 5 opening advance IVO multiplied by −1.

[0108] The aforementioned second parameter OVL is typical of the duration of the overlap step between the intake and exhaust curves (when the intake and exhaust valves are open simultaneously) and is defined as the sum of the exhaust valve closing retard EVC and the intake valve opening advance IVO.

[0109] The parameter OVL is shown diagrammatically in FIG.

[0110] According to a more specific embodiment, the aforementioned volume V of the combustion chamber cc is calculated using the following formula:

[0111]

number

[0112] where f e , g e , h e is known as a function that belongs to the packing model mentioned above.

[0113] According to another embodiment, which is applicable when the engine 1 is configured to operate in a scavenging condition (SCAV) where the intake pressure is greater than the exhaust pressure, resulting in the intake of fresh air to remove residual exhaust gases from the combustion chamber, the method comprises: s (TVC,n), the fifth map g, which is a function of the second parameter OVL and the engine rotation speed n. s (OVL,n), and the sixth map h, which is a function of lift H and engine speed n. s Based on (H,n), the volume of the combustion chamber of cylinder 2, V cc The further step of calculating

[0114] In such a case, the aforementioned first parameter TVC is equal to the exhaust valve 7 closing retard EVC, or alternatively equal to the maximum value between zero and the minimum value between the exhaust valve 7 closing retard EVC and the intake valve 5 opening advance IVO multiplied by −1.

[0115] In such a case, the aforementioned second parameter OVL is typical of the duration of the overlap step between the intake and exhaust curves and is defined as the sum of the exhaust valve closing retard EVC and the intake valve opening advance IVO, i.e., OVL = EVC + IVO.

[0116] According to a more specific embodiment, the aforementioned volume V of the combustion chamber cc is calculated using the following formula:

[0117]

number

[0118] where f s , g s , h sis known as a function that belongs to the packing model mentioned above.

[0119] According to a further embodiment, the method comprises the steps of: in the case of internal exhaust gas recirculation EGRi or scavenging SCAV, the mass M of the gas flow flowing through the overlapping steps, i.e. through the intake valve 5 and the exhaust valve 7, OVL based on the following relationship:

[0120]

number

[0121] where PERM is the hydrodynamic permeability at the time of overlap, n is the engine rotation speed, and P 0_REF is the reference pressure upstream of the passage area or at the overlap. T 0_REF is the reference temperature upstream of the passing zone or at the time of overlap. T0 is the temperature measured upstream of the passing zone or at the time of overlap.

[0122] β(P / P0,n) is the compressibility factor of the flow through the orifice, based on the ratio of the pressure downstream to the pressure upstream of the orifice and the engine speed (n). In the isentropic case, only the ratio of the upstream to downstream pressures, P / P0, is known.

[0123] In the condition of internal exhaust gas recirculation, P0 is the exhaust pressure and P is the intake pressure.

[0124] Alternatively, under scavenging conditions, P0 is the intake pressure and P is the exhaust pressure.

[0125] According to a more specific embodiment, the aforementioned hydrodynamic permeability overlap PERM is calculated according to the following relationship:

[0126]

number

[0127] A(OVL,n) is a first function based on the engine speed n and the duration OVL of the overlapping step during which the intake valve 5 and the exhaust valve 7 are simultaneously open.

[0128] fo(H,n) is a second function based on the lift H and the engine speed n.

[0129] G(g,n) is a third function based on the engine speed n and the geometric parameter g, which is representative of the center of gravity of the overlap region (i.e., of the overlapping step between each intake valve 5 and each exhaust valve 7). The geometric parameter g is representative of the angular deviation between the top dead center PMS and the aforementioned center of gravity G.

[0130] The parameters G and g are shown in FIG.

[0131] The offset of the intersection point from the top dead center PMS can be expressed as follows using the parameter g:

[0132]

number

[0133] For illustrative purposes only, the law (known in the literature and therefore not detailed) used to calculate the mass flow rate M through a section of duct (or through an opening) used to determine the mass MOVL mentioned above is given by:

[0134]

number

[0135] where A is the area of ​​the passage section; CD is the discharge coefficient; P is the pressure downstream from the passage section; P is the intake pressure of the passage section; T is the intake air temperature of the duct section; R is the gas constant referenced to the fluid flowing in the duct section; and B is the compressible flow function, which is well known (e.g., as illustrated in Figure 7).

[0136] Equation

[17] has been empirically adjusted to the filling model by integrating between the start of the overlapping step, t1, and the end of the overlapping step, t2, by the following equation:

[0137]

number

[0138] where A IS represents the isentropic region.

[0139] Substituting the variable dt with dθ / ω (where θ is the motor angle and ω is the motor rotational speed), we obtain the following equation:

[0140]

number

[0141] Finally, if we assume that the rotational speed ω of the internal combustion engine 1 is constant during the overlapping steps, the above equation can be simplified to:

[0142]

number

[0143] Exhaust pressure P EXH According to an embodiment applicable to a state of internal exhaust gas recirculation EGRi where the intake pressure P is greater than the intake pressure P, the method further comprises: EXH_EGR and the aforementioned estimated mass M of the gas flow through the overlapping steps.OVL (i.e., the mass of the gas flow that flows from the exhaust to the intake through intake valve 5 and exhaust valve 7 and is drawn back into cylinder 2 through intake valve 5 during the intake step) to give the total mass of gas M present in the cylinder, according to the following formula: EGRi The method includes the step of calculating:

[0144]

number

[0145] According to a particular embodiment, the estimated mass M of exhaust gases present in the combustion chamber under conditions of internal exhaust gas recirculation is EXH_EGR is calculated using the following relationship:

[0146]

number

[0147] where P EXH is the pressure of the detected exhaust gas flow. T EXH is the detected exhaust gas flow temperature. V cc is the estimated or calculated volume of the combustion chamber of cylinder 2. R is the fresh air and / or exhaust gas mixture constant.

[0148] Exhaust pressure P EXH According to a further embodiment of the method applicable in scavenging conditions (SCAV), where is lower than the intake pressure P and fresh air from the intake flows directly to the exhaust during the overlap to remove residual exhaust gases in the combustion chamber, the method comprises: SCAV is the estimated mass M of the gas flow through the overlapping steps. OVL and the residual mass M of exhaust gases present in the combustion chamber of the cylinder 2 and led directly to the exhaust manifold 6 through each exhaust valve 7. EXH_SCAV and the further step of calculating

[0149] Such a calculation can be performed using the following formula:

[0150]

number

[0151] According to a possible embodiment, the aforementioned residual exhaust gas mass M EXH_SCAV is calculated using the following equation:

[0152]

number

[0153] where P EXH is the pressure of the detected exhaust gas flow. EXH is the detected exhaust gas flow temperature. V cc is the estimated or calculated volume of the combustion chamber of cylinder 2. R is the fresh air and / or exhaust gas mixture constant.

[0154] f SCAV (M OVL , n) is a multiplication factor, which is the gas flow mass M OVL and is a function of engine speed n.

[0155] According to another possible embodiment, the aforementioned residual exhaust gas mass M EXH_SCAV is calculated using the following equation:

[0156]

number

[0157] where M OVL is the gas flow mass through the overlapping steps. SCAV (M OVL , n) is a multiplication factor, which is the gas flow mass (M OVL) and engine speed n. g2(g,n) is a function of the position G of the center of gravity of the overlapping steps and engine speed n.

[0158] An embodiment of a method is described that specifies in more detail how to determine the aforementioned OFF variable, which represents the mass of gases produced by combustion in the previous operating cycle that are present in cylinder 3 (either because they did not leave cylinder 3 or because they were inhaled back into cylinder 3).

[0159] The charging model is designed to determine a variable OFF that varies depending on the operating conditions, specifically the ratio of the pressure in the intake manifold 4 to the pressure in the exhaust manifold 6.

[0160] When the pressure in the exhaust manifold 6 is higher than the pressure in the intake manifold 4 (internal EGR mode), the variable OFF corresponds to the total mass MEGRi of the internal EGR expressed by the above equation [Equation 21].

[0161] When the pressure in the intake manifold 4 is higher than the pressure in the exhaust manifold 6 ("scavenging" mode), the OFF variable is instead expressed by the following equation (with the variables already explained):

[0162]

number

[0163] In this case, in fact, the gases produced by combustion in the previous operating cycle and present in cylinder 2 (because they did not exit) are led at least partially directly through each exhaust valve 7 to the exhaust manifold 6 during the overlapping step. The value assumed by the OFF variable is a positive value or zero. If the entire flow of gases produced by combustion in the previous operating cycle and present in cylinder 3 is led directly through exhaust valve 7 to the exhaust manifold 6 during the overlapping step, the electronic control unit 10 is configured to saturate the OFF variable to a zero value.

[0164] If the OFF variable becomes negative, for example due to dynamic and cooling effects within the combustion chamber of cylinder 3, the electronic control unit 10 may be configured to saturate the OFF variable to a negative value.

[0165] The model described above has been implemented in a control unit and experimentally confirmed to have satisfactory results, i.e., an absolute error of less than 3% has been confirmed when compared with measurements of the air mass on an engine bench.

[0166] That is, according to an embodiment of the method, the step of determining the mass of gases present in cylinder 2, which were produced by combustion in the previous operating cycle OFF, first determines the exhaust gas flow pressure P in exhaust manifold 6. EXH is higher or lower than the intake gas flow pressure P in the intake manifold 4.

[0167] Pressure in the exhaust manifold P EXH is higher than the pressure in the intake manifold P, based on the charging model, the exhaust gas flow pressure P EXH , the temperature of the exhaust gas flow T EXH , the volume of the combustion chamber of the cylinder V cc , and the mass M that flows from the exhaust to the intake through the intake valve 5 and the exhaust valve 7 and is drawn back into the cylinder 2 through the intake valve 5 during the intake step. OVLand calculating a mass OFF of gases produced by combustion in the previous operating cycle and present in cylinder 2 from said second group of reference quantities.

[0168] Pressure in the exhaust manifold P EXH is lower than the pressure in the intake manifold, P, based on the charging model, the exhaust gas flow pressure, P EXH , the temperature of the exhaust gas flow T EXH , the volume of the combustion chamber of the cylinder V cc , and the residual mass M of exhaust gases present in the combustion chamber of the cylinder 2 and led directly to the exhaust manifold 6 through each exhaust valve 7. EXH_SCAV and determining a measured or estimated value for each of a second group of reference quantities including: ##EQU1## and calculating a mass OFF of gases produced by combustion in the previous operating cycle and present in cylinder 2 from said second group of reference quantities.

[0169] According to an embodiment, if the pressure PEXH in the exhaust manifold is higher than the pressure P in the intake manifold, the mass OFF of gases produced by combustion in the previous operating cycle and present in cylinder 2 is calculated using the following relationship:

[0170]

number

[0171] where R is the fresh air and / or exhaust gas mixture constant.

[0172] According to an embodiment, the quantity M OVL is calculated using equation

[14] , taking into account the above equation

[15] .

[0173] According to another embodiment, the pressure P in the exhaust manifold EXHis lower than the pressure P in the intake manifold, the mass OFF of gases produced by combustion in the previous operating cycle and present in cylinder 2 is calculated using the above equation [Equation 26]. TIFF2025172779000029.tif10150

[0174] where R is the fresh air and / or exhaust gas mixture constant.

[0175] According to an embodiment, the quantity M EXH_SCAV is calculated using the above-mentioned formula

[24] or formula

[25] .

[0176] According to a further embodiment of the method, the estimation of the amount of air trapped in the cylinder is refined by taking into account an empirical correction factor.

[0177] Specifically, according to such an embodiment, the mass m of air trapped in each cylinder 2 is calculated by a number of multiplication coefficients (K1, K2) that take into account the angle of angular displacement VVTi of the intake valve 5, the angle of angular displacement (VVTe) of the exhaust valve 7, and the rotational speed n of the internal combustion engine 1.

[0178] According to an embodiment, the mass m of air trapped in each cylinder 2 is calculated as a function of a first multiplication factor K1 taking into account the intake valve displacement angle VVti and the exhaust valve displacement angle VVte, and as a function of a second multiplication factor K2 taking into account the rotational speed n of the internal combustion engine and the exhaust valve displacement angle VVte.

[0179] According to a particular embodiment, the mass m of air trapped in each cylinder 2 is calculated by the following relationship:

[0180]

number

[0181] where K Tis the temperature T detected in the intake manifold 4 and the engine coolant temperature T H2O is the third coefficient determined by

[0182] According to an embodiment, the coefficient K T is calculated by the following formula:

[0183]

number

[0184] The mass M recirculated by the external circuit to each cylinder per cycle EGRe An embodiment of the method is described which can be used for an internal combustion engine 1 equipped with an external exhaust gas recirculation circuit EGRe with a known flow rate corresponding to:

[0185] According to such an embodiment, the step of calculating the mass m of air trapped in each cylinder 2 comprises calculating the mass m of air trapped in each cylinder 2 according to the following formula:

[0186]

number

[0187] According to an embodiment, the step of calculating the mass m of air trapped in each cylinder 2 comprises calculating the mass m of air trapped in each cylinder 2 according to the following formula:

[0188]

number

[0189] According to the embodiment, the external EGR mass flow rate M EGR (This M is M with a dot above) is known, and the total number of intake cylinders is N cyl If , the external EGR mass M taken by each cylinder per cycle EGReis derived from the following equation [Equation 32], and therefore the equation [Equation 33] is obtained.

[0190]

number

[0191]

number

[0192] The conditions under which scavenging occurs and furthermore the internal combustion engine 1 is operated with a mass M recirculated by an external circuit to each cylinder per cycle. EGRe An embodiment of the method is described which can be used in a situation with an external exhaust gas recirculation circuit EGRe with a known flow rate corresponding to:

[0193] In such an embodiment, the method further comprises: EGRe and the total volume M aspirated by the engine per cylinder per cycle, which is the total volume of gas mixture flowing in the intake duct 6 of cylinder 2. TOT The ratio R between EGR Therefore, R EGR =M EGRe / M TOT is.

[0194] Furthermore, during the overlapping steps, the mass of air flowing from the intake manifold to the exhaust manifold, M SCAV The step to calculate the total volume of gas in the cylinder M is SCAV This includes calculating

[0195]

number

[0196] The situation in which scavenging occurs and furthermore, the internal combustion engine 1 is configured to generate a mass M recirculated by an external circuit to each cylinder per cycle. EGRe An embodiment of the method is described which can be used in a situation with an external exhaust gas recirculation circuit EGRe with a known flow rate corresponding to:

[0197] In such an embodiment, the method further comprises: EGRe and the total volume M aspirated by the engine per cylinder per cycle, which is the total volume of gas mixture flowing in the intake duct 6 of cylinder 2. TOT The ratio R between EGR The further step of calculating

[0198] Further, the step of calculating the mass OFF of gases produced by combustion in the previous operating cycle and present in cylinder 2 is calculated by the following equation:

[0199]

number

[0200] According to an embodiment of the method, the aforementioned relationship between the mass trapped in the cylinder 2 and the intake pressure P in the intake duct 4 is expressed through the following equation:

[0201]

number

[0202] According to different conceivable embodiments of the method, the intake pressure P and / or the intake valve lift H and / or the intake valve angular displacement VVTi and / or the exhaust valve angular displacement VVTe and / or the temperature T in the intake manifold 4 and / or the engine coolant temperature T H2O and / or the exhaust pressure P in the exhaust manifold 6 EXH and / or the detected temperature T of the exhaust gas flow EXHare detected through respective sensors placed at respective positions.

[0203] According to different embodiments of the method, the aforementioned coefficients or maps or functions f v (IVC,n) and / or f h (H,n) and / or f p (P,n) and / or f1(T,P) and / or f2(TH2O,P) and / or f e (TVC,n) and / or g e (OVL,n) and / or h e (OVL,n) and / or f s (TVC,n) and / or g s (OVL,n) and / or h s (OVL,n) and / or β(P / P0,n) and / or A(OVL,n) and / or fo(H,n) and / or G(g,n) and / or f SCAV (M OVL ,n) and / or g2(g,n) and / or K1 and / or K2 and / or K T is determined by a known theoretical relationship or a relationship obtained by an experiment or characterization step performed on the engine 1 before use under operating conditions and is stored in a storage means accessible to the means 10 for controlling the operation of the engine 1.

[0204] The aforementioned steps of calculating or determining are carried out by one or more processing units included in the means 10 for controlling the operation of the engine 1 (for example the aforementioned control unit 10).

[0205] The estimate of the mass of air trapped in the cylinders 3, according to any of the embodiments described above, can be used in many useful ways, such as to obtain a target value for the exhaust gas air / fuel ratio (or title). That is, once the mass of air trapped in each cylinder 3, m, is determined through the charge model for each cycle, the electronic control unit 30 is configured to determine the amount of fuel to be injected into the cylinder 3 that will obtain the target value for the exhaust gas air / fuel ratio.

[0206] Also preferably, the above-described relationship between the mass m of air trapped in the cylinder and the intake pressure P (or other quantity) can be expressed as a function of the intake pressure P (or other quantity) to obtain a "target value."

[0207] In this regard, a method for controlling and implementing the operation of at least one cylinder 2 of an internal combustion engine 1, also included in the present invention, is described (such a method will be referred to hereinafter as a "charge and control model" or "charge model" for the sake of brevity).

[0208] Such a method may involve determining a target mass M of combustion air required in each cylinder 2 to meet engine torque demands, based on a computational model that uses measured and / or estimated physical quantities. OBJ , which derives a relationship between the mass trapped in the cylinder 2 and the intake pressure P in the intake duct 4.

[0209] The method for controlling and executing the operation of at least one cylinder also includes: determining a target mass M within the cylinder 2 as a function of measured, estimated or applied intake valve lift H and / or intake valve displacement angle VVTi and / or exhaust valve displacement angle VVTe of the intake valve 5 based on the aforementioned relationship between the mass trapped within the cylinder 2 and the intake pressure P; OBJ The target pressure value P that must be present in the intake manifold 4 in order to obtain OBJand finally calculate the aforementioned target pressure P OBJ and the aforementioned target mass M OBJ Operate the pressure and flow control valve of the intake line 4 to obtain

[0210] According to the embodiment, a target mass M confined within a cylinder 2 OBJ and the target intake pressure P in the intake duct 4 OBJ The above-mentioned relationship between is expressed by the following equation:

[0211]

number

[0212] where OFF is the mass of gas present in the cylinder produced by combustion in the previous operating cycle. v (IVC,n), f h (H,n), f p (P,n) is a product map that represents the actual volume V in each cylinder 2. The first map f v (IVC,n) is a function of the intake valve closing retard angle IVC and the engine speed n. h (H, n) is a function of the intake valve lift H and the engine rotation speed n. p (P, n) is a function of intake pressure P and engine speed n.

[0213] K1 and K2 are multiplication factors that take into account the angle of the intake valve angular displacement VVTi, the angle of the exhaust valve angular displacement VVTe, and the rotational speed n of the engine 1.

[0214] K T is a coefficient based on the temperature T sensed in the intake manifold 4 and the temperature TH2O of the engine coolant.

[0215] According to the embodiment already described, K T can be expressed by the following equation

[29] : TIFF2025172779000040.tif6150

[0216] A method for controlling and implementing the operation of a cylinder of an internal combustion engine is described in more detail below, by way of example.

[0217] According to an embodiment, in the electronic control unit 10, a calculation chain is also stored, which starts from the engine torque requested by the user by actuating the accelerator pedal and calculates the combustion air mass M required in each cylinder 2 to meet such engine torque request. OBJ The calculation chain, following the action of the user on the accelerator pedal, determines, through the maps stored in the electronic control unit 10 and knowing the rotational speed (or rpm) n of the engine 1, the required engine torque C at the drive shaft 11. r Based on this, the total drive torque C required by the drive shaft 11 is calculated. t Calculate the engine torque C required for each cylinder 2. t_cyl The calculation chain also calculates the aforementioned engine torque value C t_cyl To obtain the mass of combustion air required in each cylinder 2, M OBJ It is configured to find

[0218] First, engine torque value C t_cyl To obtain the aforementioned mass M OBJ Once calculated, the electronic control unit 30 is ready to use the equation between m and P described above (e.g., the aforementioned equations [1],

[10] ,

[28] or

[31] of the filling model) inversely (expressed explicitly in terms of variables different from m) to the one described above.

[0219] That is, the mass M of combustion air required for each cylinder 2 OBJ (in this case, corresponding to the mass m of air trapped in each cylinder 2 at each cycle according to one of the above equations), the target pressure value P in the intake manifold 4 OBJis calculated from the same formula. For example, starting from formula

[28] , we change m to M OBJ As P to P OBJ This gives the following equation:

[0220]

number

[0221] The throttle valve 12 is set to the target pressure value P OBJ is consequently controlled by the electronic control unit 10 to obtain

[0222] Typically, the dynamics of the throttle valve are faster than the dynamics of the VVH, which are faster than or comparable to the dynamics of the VVT, so the charge control principle described above works correctly.

[0223] If the dynamics of the VVH are higher than the dynamics of the throttle valve (or intake manifold), or if there is no throttle valve, the fill model can be used to calculate the target H lift, given the target air mass.

[0224] As noted above, the filling model stored in electronic control unit 10 uses measured and / or estimated physical quantities (such as temperature and pressure values). The filling model may also use other measured and / or targeted physical quantities, such as VVT position (which can be measured to estimate m and can be measured or "targeted" for the control and filling model), and / or VVH position (which can be measured to estimate m and can be measured or "targeted" for the control and filling model).

[0225] The charging and control model described herein has been tested, for example, on a 1,500cc turbo engine with intake and exhaust VVH and VVT, and has been found to be accurate to within the performance figure established for this type of control, i.e., ±3%.

[0226] In all the situations described above, it is possible to calculate the flow rate of the internal combustion engine 1 starting from an estimate of the mass per cylinder and per engine cycle, taking into account the number of cylinders and the engine speed n (specifically, starting from an estimate of the mass per cylinder and per engine cycle, multiplying it by the number of cylinders, the engine speed n, and 1 / 2).

[0227] As is apparent, the objects of the present invention are fully achieved by the above estimation and control method, the advantages of which are apparent from the above description.

[0228] Specifically, the described method, and the associated charge model, allows the mass of air trapped in each cylinder, m, to be determined, as well as the total air mass M aspirated by the internal combustion engine. TOT and / or scavenging mass M SCAV and / or internal EGR mass M EGRI can be obtained.

[0229] The determination of the aforementioned variables is performed by the method efficiently, i.e., with adequate accuracy (based on experimentation, as discussed above), effectively, i.e., quickly and without requiring excessive computing power from the electronic control unit 10, and cost-effectively since it does not require the installation of expensive additional components and / or sensors such as air flow meters.

[0230] For the above-described embodiments of the method for determining the mass of air trapped in each cylinder of an internal combustion engine and the method for controlling and executing the operation of at least one cylinder of an internal combustion engine, those skilled in the art may make modifications, adjustments and substitutions of parts with other functional equivalents to meet any fortuitous requirements without departing from the scope of the claims.

[0231] All symbol conventions used in all the above formulas are intended to be consistent with the figures shown in the accompanying drawings.

[0232] In all the above equations, all quantities expressed as functions can be understood as maps and / or stored vectors.

[0233] All features described above as belonging to one possible embodiment may be implemented independently of other described embodiments. It should further be noted that the term "comprises" does not exclude other elements or steps, and the article "a" does not exclude a plurality. The drawings are not to scale, in order to emphasize the need to properly highlight the various parts for a clearer illustration.

Claims

1. 1. A method for determining the mass (m) of air trapped in each cylinder (2) of an internal combustion engine (1) comprising a plurality of cylinders (2), each of said cylinders (2) being connected to an intake manifold (4) and an exhaust manifold (6), each of said cylinders (2) receiving fresh air from said intake manifold (4) by at least one respective intake valve (5) and directing exhaust gases produced by combustion into said exhaust manifold (6) by at least one respective exhaust valve (7); The at least one intake valve (5) is driven to controllably change the lift (H) of the intake valve (5); The method comprises: determining, based on a charging model using measured and / or estimated physical quantities, a value for each of a first group of reference quantities, including the intake pressure (P) measured in the intake manifold (4), the engine rotation speed (n), and the mass (OFF) of gases produced by combustion in the previous operating cycle and present in the cylinder (3), estimated as a function of the lift (H) and the intake valve closing retard (IVC) based on the lift (H); determining an effective internal volume (V) of each cylinder (2) as a function of the engine speed (n), the intake valve lift (H), and the intake valve closing retard (IVC) based on the charging model; The mass (m) of air trapped in each cylinder (2) as a function of the first group of reference quantities and the actual volume (V) within each cylinder (2) is calculated according to the relationship: m=(P*V)-OFF and obtaining the result through the step of:

2. The at least one intake valve (5) is also actuated to controllably vary the intake valve angular displacement (VVTi) and / or the at least one exhaust valve (7) is actuated to controllably vary the exhaust valve angular displacement (VVTe); 2. The method of claim 1, wherein the step of determining a value of a first group of reference quantities includes determining the intake valve closing retard (IVC) based on both the intake valve lift (H) and the intake valve angular displacement (VVTi).

3. The step of determining the actual internal volume (V) of each cylinder includes: First map (f ｖ (IVC, n)), the second map (f ｈ (H, n)), the third map (f ｐ (P, n)) The first map (f ｖ (IVC, n)) is a function of the intake valve closing retard (IVC) and the engine rotation speed (n), and the second map (f ｈ (H, n)) is a function of the intake valve lift (H) and the internal combustion engine rotation speed (n), and the third map (f ｐ 3. The method of claim 1 or claim 2, wherein (P,n) is a function of the intake air pressure (P) and the engine speed (n).

4. The actual internal volume (V) of each cylinder (2) is determined by the relationship: V=f ｖ (IVC,n)*f ｈ (H,n)*f ｐ (P,n) The method of claim 3, wherein the calculated value is:

5. The first group of reference quantities further comprises the temperature (T) sensed in the intake manifold (4) and the temperature (T Ｈ２Ｏ ), The step of determining the mass (m) of air trapped in each cylinder (2) includes determining the mass (m) of air trapped in each cylinder (2) as a function of the first group of reference quantities and the actual volume (V) in each cylinder (2) according to the relationship: m=[(P*V)-OFF]*f １ (T,P)*f ２ (T Ｈ２Ｏ ,P) Calculating via f １ (T, P) and f ２ (T Ｈ２Ｏ 5. The method according to claim 1, wherein P is a known function belonging to the filling model.

6. 6. The method according to claim 1, further comprising the step of: driving the intake valve (5) by an intake valve lift adjuster (50) by controlling and varying the intake valve lift law so as to determine both the lift (H) and the intake valve opening advance (IVO) and the intake valve closing retard (IVC) with a single degree of freedom (γ).

7. The driving step includes: relationship: I (H) = I ｈｍａｘ -Δivo(H) determining the intake valve opening advance (IVO) by relationship: IVC(H)=IVC ｈｍａｘ -Δivc(H) and determining the intake valve closing retard (IVC) by IVO ｈｍａｘ is the intake valve opening advance angle corresponding to the maximum lift, Δiv(H) is the variation of the intake valve opening advance angle based on the controlled lift (H), IVC ｈｍａｘ is the intake valve closing retard corresponding to the maximum lift, and Δivc(H) is the variation of intake valve closing retard based on the controlled lift (H).

8. further driving the intake valve (5) by an intake valve phaser (51) by controlling and varying the intake valve angular displacement (VVTi) so that both the intake valve opening advance (IVO) and the intake valve closing retard (IVC) are based not only on the lift (H) but also on the intake valve angular displacement (VVTi); 7. The method according to claim 6, when dependent on claim 2, further comprising the step of: driving the exhaust valve (7) by an exhaust valve phaser (52) by controlling and varying the exhaust valve angular displacement (VVTe) so that both an exhaust valve opening advance (EVO) and an exhaust valve closing retard (EVC) are based on the exhaust valve angular displacement (VVTe).

9. The driving step includes: The opening advance (IVO) is defined by the relationship: I (H) = I ｒｅｆ -Δivo(H)-VVT) and The intake valve closing retard (IVC) is determined by the relationship: IVC(H)=IVC ｒｅｆ -Δivc(H)+VVTi and The exhaust valve opening advance (EVO) is determined by the relationship: EVO=EO ｒｅｆ -VVT% and The exhaust valve closing retard (EVC) is determined by the relationship: EVC=EVC ｒｅｆ +VVTe and determining the value by IVO ｒｅｆ is the reference value of the intake valve opening advance angle when there is no phase adjustment, and VVTi is the reference value IVO ｒｅｆ are displacement angles of the intake valve phaser (51) relative to respective reference positions corresponding to IVC ｒｅｆ is the reference value of the intake valve closing retard in the absence of phase adjustment, EVO ｒｅｆ is the reference value of the exhaust valve opening advance in the case where there is no phase adjustment, and VVTe is the reference value EVO ｒｅｆ and the displacement angle of the exhaust valve phaser (52) relative to a respective reference position indicated by EVC ｒｅｆ 9. The method of claim 7, wherein: is the reference value of the exhaust valve closing retard in the absence of phasing.

10. When the engine (1) operates under conditions of exhaust gas internal recirculation (EGRi), A fourth map f which is a function of the first parameter (TVC) and the engine rotation speed (n) ｅ (TVC, n), the second parameter (OVL) and the fifth map g which is a function of the engine rotation speed (n). ｅ (OVL, n), and a sixth map h which is a function of the lift (H) and the engine rotation speed (n). ｅ Further comprising the step of calculating a combustion chamber volume (Vcc) of the cylinder (2) based on (H, n); the first parameter (TVC) is alternatively equal to the exhaust valve closing retard (EVC) of the exhaust valve (7) or the maximum value between zero and the minimum value of the closing retard (EVC) of the exhaust valve (7) and the opening advance (IVO) of the intake valve (5) multiplied by -1; 10. The method according to claim 1 to 9, wherein the second parameter (OVL) is typical of the duration of the overlap step between the intake curve and the exhaust curve and is defined as the sum of the exhaust valve closing retard (EVC) and the intake valve opening advance (IVO).

11. The combustion chamber volume (V ｃｃ ) has the formula: V ｃｃ =f ｅ (TVC,n)*g ｅ (OVL,n)*h ｅ (H,n) is calculated by f ｅ , g ｅ , h ｅ The method of claim 10 , wherein is a known function belonging to the filling model.

12. When the engine (1) is configured to operate under scavenging conditions, where the intake pressure is greater than the exhaust pressure, thus resulting in the intake of fresh air to remove residual exhaust gases in the combustion chamber, the method comprises: A fourth map f which is a function of the first parameter (TVC) and the engine rotation speed (n) ｓ Based on (TVC, n), a fifth map g, which is a function of the second parameter (OVL) and the engine rotation speed (n), is calculated. ｓ (OVL, n) and a sixth map h which is a function of the lift (H) and the engine rotation speed (n). ｓ Based on (H, n), the combustion chamber volume (V ｃｃ ), the first parameter (TVC) is alternatively equal to the exhaust valve closing retard (EVC) of the exhaust valve (7) or the maximum value between zero and the minimum value of the closing retard (EVC) of the exhaust valve (7) and the opening advance (IVO) of the intake valve (5) multiplied by -1; 10. The method according to claim 1, wherein the second parameter (OVL) is typical of the duration of the overlap step between the intake and exhaust curves and is defined as the sum of the exhaust valve closing retard (EVC) and the intake valve opening advance (IVO).

13. The combustion chamber volume (V ｃｃ ) has the formula: V ｃｃ =f ｓ (TVC,n)*g ｓ (OVL,n)*h ｓ (H,n) is calculated by f ｓ , g ｓ , h ｓ The method of claim 12 , wherein is a known function belonging to the filling model.

14. In case of exhaust gas internal recirculation (EGRi) or scavenging (SCAV), the mass of the gas flow (M ＯＶＬ ) and the relationship: M ＯＶＬ =PERM*β(P / P ０ ,n)*P ０ / P ０＿ＲＥＦ *(T ０＿ＲＥＦ / T ０ ) １／２ / n and further comprising the step of calculating based on PERM is the hydrodynamic permeability at overlap, n is the engine speed, P ０＿ＲＥＦ is the reference pressure upstream of the passage area or at the overlap, T ０＿ＲＥＦ is the reference temperature upstream or overlap of the passing zone, T0 is the temperature measured upstream of the passing zone or at the time of the overlap; β (P / P ０ , n) is the compression factor of the flow through the opening based on the ratio of pressures downstream to upstream of the opening and the engine speed (n); Under conditions of internal recirculation of exhaust gases, P ０ is the exhaust pressure, P is the intake pressure, Or, under scavenging conditions, P ０ 14. The method of any one of claims 1 to 13, wherein P is the intake pressure and P is the exhaust pressure.

15. The hydrodynamic permeability (PERM) at the time of overlap is determined by the following relationship: PERM=A(OVL,n)*fo(H,n)*G(g,n) is calculated by A(OVL,n) is a first function based on the engine speed (n) and the duration of the overlapping step (OVL) during which the intake valve (5) and the exhaust valve (7) are simultaneously open; fo(H,n) is a second function based on the lift (H) and the engine speed (n); 15. The method of claim 14, wherein G(g,n) is a third function representative of the center of gravity of the overlap region based on the engine speed (n) and a geometric parameter (g) representative of the angular deviation between top dead center and the center of gravity of the overlapping step (G).

16. The exhaust pressure (P ＥＸＨ ) is higher than the intake pressure (P), the method comprising: The total mass of gas present in the cylinder (M ＥＧＲｉ ) is the estimated mass of exhaust gas in the combustion chamber under the condition of internal exhaust gas recirculation (M ＥＸＨ＿ＥＧＲ ) and the estimated mass (M ＯＶＬ ), i.e. the mass of the gas flow flowing from the exhaust to the intake through the intake valve (5) and the exhaust valve (7) and during the intake step, drawn back into the cylinder (2) through the intake valve (5), as expressed by the formula: M ＥＧＲｉ =M ＯＶＬ +M ＥＸＨ＿ＥＧＲ The method of claim 14 or claim 15, further comprising the step of calculating by:

17. The estimated mass (M ＥＸＨ＿ＥＧＲ ) is related to the following: M ＥＸＨ＿ＥＧＲ =(P ＥＸＨ *V ｃｃ ) / (R*T ＥＸＨ ) is calculated by P ＥＸＨ is the gas flow pressure sensed at the exhaust, T ＥＸＨ is the gas stream temperature sensed at the exhaust, V ｃｃ is the estimated or calculated volume of the combustion chamber of the cylinder (2), 17. The method of claim 16, wherein R is a constant for the fresh air and / or exhaust gas mixture.

18. The exhaust pressure (P ＥＸＨ ) is lower than the intake pressure (P), and during overlap, the fresh air from the intake flows directly towards the exhaust to remove residual exhaust gases in the combustion chamber, under scavenging conditions (SCAV), the method comprising: During the overlapping step, the total air mass (M ＳＣＡＶ ) by dividing the estimated mass (M ＯＶＬ ) and the residual mass (M) of exhaust gases present in the combustion chamber of the cylinder (2) and led directly to the exhaust manifold (6) through each exhaust valve (7). ＥＸＨ＿ＳＣＡＶ ) as the difference between the formula: M ＳＣＡＶ =M ＯＶＬ -M ＥＸＨ＿ＳＣＡＶ The method of claim 14 or claim 15, further comprising the step of calculating by:

19. The exhaust gas residual mass (M ＥＸＨ＿ＳＣＡＶ ) is related to the following: M ＥＸＨ＿ＳＣＡＶ =[(P ＥＸＨ *V ｃｃ ) / (R*T ＥＸＨ )]*f ＳＣＡＶ (M ＯＶＬ ,n) is calculated by P ＥＸＨ is the gas flow pressure sensed at the exhaust, T ＥＸＨ is the gas stream temperature sensed at the exhaust, V ｃｃ is the estimated or calculated volume of the combustion chamber of the cylinder (2), R is the fresh air and / or exhaust gas mixture constant; f ＳＣＡＶ (M ＯＶＬ , n) is the gas flow mass (M ＯＶＬ 20. The method of claim 18, wherein the engine speed (n) is a multiplication factor that is a function of (n) and the engine speed (n).

20. The exhaust gas residual mass (M ＥＸＨ＿ＳＣＡＶ ) is related to the following: M ＥＸＨ＿ＳＣＡＶ =M ＯＶＬ *f ＳＣＡＶ (M ＯＶＬ ,n)*g ２ (g,n) is calculated by M ＯＶＬ is the gas flow mass through the overlapping steps, f ＳＣＡＶ (M ＯＶＬ , n) is the gas flow mass (M ＯＶＬ ) and a multiplication factor that is a function of the engine speed (n), g ２ 19. The method of claim 18, wherein (g, n) is a function of the position of the center of gravity (G) of the overlapping steps and the engine speed (n).

21. The step of determining the mass (OFF) of gases present in the cylinder (2) produced by combustion in the previous operating cycle, The exhaust gas flow pressure (P ＥＸＨ ) is higher or lower than the intake gas flow pressure (P) in the intake manifold (4); The exhaust manifold pressure (P ＥＸＨ ) is higher than the intake manifold pressure (P), Based on the charging model, the pressure of the exhaust gas flow (P ＥＸＨ ), the temperature of the exhaust gas flow (T ＥＸＨ ), the volume of the combustion chamber of the cylinder (V ｃｃ ), and the mass (M ＯＶＬ determining measured or estimated values ​​for each of a second group of reference quantities including calculating the mass (OFF) of gases produced by combustion in the previous operating cycle and present in said cylinder (2) as a function of said second group of reference quantities; The exhaust manifold pressure (P ＥＸＨ ) is lower than the intake manifold pressure (P), Based on the charging model, the pressure of the exhaust gas flow (P ＥＸＨ ), the temperature of the exhaust gas flow (T ＥＸＨ ), the volume of the combustion chamber of the cylinder (V ｃｃ ), and the residual mass (M ＥＸＨ＿ＳＣＡＶ determining measured or estimated values ​​for each of a second group of reference quantities including and calculating the mass (OFF) of gases produced by combustion in a previous operating cycle and present in the cylinder (2) as a function of the second group of reference quantities.

22. The pressure in the exhaust manifold (P ＥＸＨ ) is higher than the pressure in the intake manifold (P), the mass of gases (OFF) produced by combustion in the previous operating cycle and present in the cylinder (2) is given by the following relationship: OFF=M ＯＶＬ +(P ＥＸＨ *V ｃｃ ) / (R*T ＥＸＨ ) is calculated by 22. The method of claim 21, wherein R is a constant for the fresh air and / or exhaust gas mixture.

23. M ＯＶＬ The method according to claim 22 when dependent on claim 14 or claim 15, wherein is calculated by the method according to claim 14 or claim 15.

24. The pressure in the exhaust manifold (P ＥＸＨ ) is lower than the pressure in the intake manifold (P), the mass of gas (OFF) produced by combustion in the previous operating cycle and present in the cylinder (2) is given by the following relationship: OFF=(P ＥＸＨ *V ｃｃ ) / (R*T ＥＸＨ )-M ＥＸＨ＿ＳＣＡＶ is calculated by 22. The method of claim 21, wherein R is a constant for the fresh air and / or exhaust gas mixture.

25. M ＥＸＨ＿ＳＣＡＶ The method of claim 24 when dependent on claim 19 or claim 20, wherein is calculated by the method of claim 19 or claim 20.

26. The mass (m) of air trapped in each cylinder (2) is multiplied by a number of multiplication factors (K) that take into account the angle of intake valve angular displacement (VVT i ), the angle of exhaust valve angular displacement (VVT e ) and the rotational speed (n) of the internal combustion engine (1). １ , K. ２ 26. The method of claim 1, wherein the value of the sigma is calculated by:

27. The mass (m) of air trapped in each cylinder (2) is: a first multiplication factor (K) that takes into account the angle of intake valve angular displacement (VVT i ) and the angle of exhaust valve angular displacement (VVT e ); １ ) functions, as well as a second multiplication factor (K) that takes into account the rotational speed (n) of the internal combustion engine (1) and the angle of exhaust valve angular displacement (VVTe); ２ 27. The method of claim 26, wherein the value of the sigma is calculated as a function of sigma.

28. The mass (m) of air trapped in each cylinder (3) is determined by the following relationship: m=[(P*V)-OFF]*K Ｔ *K １ (VVT ｉ ,VVT ｅ )*K ２ (VVT ｅ ,n) is calculated by K Ｔ is the temperature (T) detected in the intake manifold (4) and the temperature (T Ｈ２Ｏ 28. The method of claim 27, wherein the third multiplication factor is based on

29. The internal combustion engine (1) has a mass (M ＥＧＲｅ an external exhaust gas recirculation circuit (EGRe) with a known flow rate corresponding to the The step of calculating the mass (m) of air trapped in each cylinder (2) may include calculating the mass (m) of air trapped in each cylinder (2) using the following formula: m=(P*V-OFF)*f １ (T,P)*f ２ (T Ｈ２Ｏ ,P)-M ＥＧＲｅ 29. The method of any one of claims 1 to 28, comprising calculating by:

30. The step of calculating the mass (m) of air trapped in each cylinder (2) may include calculating the mass (m) of air trapped in each cylinder (2) using the following formula: m=[(P*V)-OFF]*K Ｔ *K １ (VVT ｉ ,VVT ｅ )*K ２ (VVT ｅ ,n)-M ＥＧＲｅ 30. The method of claim 29 when dependent on claim 28, comprising calculating by:

31. A scavenging state occurs, and the internal combustion engine (1) is configured to have a mass (M ＥＧＲｅ an external exhaust gas recirculation circuit (EGRe) with a known flow rate corresponding to The method comprises: determining the mass (M ＥＧＲｅ ) and the total mass inhaled by the engine per cylinder per cycle (M ＴＯＴ ), i.e., the ratio (R ＥＧＲ ), During the overlapping step, the mass of air flowing from the intake manifold to the exhaust manifold (M ＳＣＡＶ ) is related to the following: M ＳＣＡＶ =(M ＯＶＬ -M ＥＸＨ＿ＳＣＡＶ )*(1-R ＥＧＲ ) 21. The method of any one of claims 18 to 20, wherein the value is calculated by:

32. A scavenging state occurs, and the internal combustion engine (1) is configured to have a mass (M ＥＧＲｅ an external exhaust gas recirculation circuit (EGRe) with a known flow rate corresponding to The method comprises: determining the mass (M ＥＧＲｅ ) and the total mass inhaled by the engine per cylinder per cycle (M ＴＯＴ ), i.e., the ratio (R ＥＧＲ ), Calculating the mass of gases (OFF) present in said cylinder (2) produced by combustion in the previous operating cycle is carried out using the following relationship: OFF=(P ＥＸＨ *V ｃｃ ) / (R*T ＥＸＨ )-[M ＥＸＨ＿ＳＣＡＶ *(1-R ＥＧＲ )] 26. The method of claim 24 or claim 25, wherein the value is calculated by:

33. The relationship between the target mass trapped in the cylinder (2) and the target intake pressure (P) in the intake duct (4) is given by the following formula: m=[(P*f ｖ (IVC,n)*f ｈ (H,n)*f ｐ (P,n))-OFF]*K Ｔ *K １ (VVT ｉ ,VVT ｅ )*K ２ (VVT ｅ ,n) 33. The method of any one of claims 1 to 32, expressed by:

34. the intake pressure (P) and / or the lift (H) of the intake valve and / or the intake valve angular displacement (VVT i ) and / or the exhaust valve angular displacement (VVT e ) and / or the temperature (T) in the intake manifold (4) and / or the temperature (T Ｈ２Ｏ ) and / or the exhaust pressure (P ＥＸＨ ) and / or the detected temperature (T ＥＸＨ 34. The method of claim 1, wherein each of the plurality of sensors is detected by a respective sensor located at each of the positions.

35. The coefficient or map or function f ｖ (IVC, n) and / or f ｈ (H, n) and / or f ｐ (P, n) and / or f0(T, P) and / or f2(T Ｈ２０ , P) and / or fe(TVC, n), and / or g ｅ (OVL, n) and / or he(OVL, n) and / or f ｓ (TVC, n), and / or g ｓ (OVL, n) and / or h ｓ (OVL, n) and / or β(P / P ０ , n) and / or A(OVL, n) and / or fo(H, n) and / or G(g, n) and / or f ＳＣＡＶ (M ＯＶＬ , n) and / or g ２ (g, n) and / or K １ and / or K ２ , and / or K Ｔ is determined by a known theoretical relationship or a relationship obtained by an experiment or characterization step performed on the engine (1) before use under operating conditions, and is stored in a storage means accessible to the means (2) for controlling the operation of the engine (1); 35. A method according to any one of the preceding claims, wherein the calculating or determining step is performed by one or more processing units comprising the means (10) for controlling the operation of the engine (1).

36. A method for controlling and executing the operation of at least one cylinder (2) of an internal combustion engine (1), comprising: Based on a computational model using measured and / or estimated physical quantities, a target mass of combustion air (M) required in each cylinder (2) to meet engine torque demands is determined. ＯＢＪ ) and - obtaining a relationship between the mass trapped in each cylinder (2) and the intake pressure (P) in the intake duct (4) by carrying out a method for determining the mass (m) of air trapped in each cylinder (2) according to claims 1 to 35; and determining a target mass (M) in the cylinder (2) based on the relationship obtained between the mass trapped in the cylinder (2) and the intake pressure (P) as a function of the measured, estimated or set values ​​of the lift (H) of the intake valve (5) and / or the angle of intake valve angular displacement (VVTi) and / or the angle of exhaust valve angular displacement (VVTe). ＯＢＪ ) to obtain a target pressure value (P ＯＢＪ ) and The target pressure (P ＯＢＪ ) and the target mass (M ＯＢＪ and operating the pressure and flow control valves of said intake duct (4) to obtain

37. A target mass (M ＯＢＪ ) and the target intake pressure (P ＯＢＪ ) is expressed by the following formula: M ＯＢＪ =[(P ＯＢＪ *f ｖ (IVC,n)*f ｈ (H,n)*f ｐ (P,n))-OFF]*K Ｔ *K １ (VVT ｉ ,VVT ｅ )*K ２ (VVT ｅ ,n) is expressed by OFF is the mass of gas present in said cylinder (2) produced by combustion in the previous operating cycle; f ｖ (IVC, n), f ｈ (H, n), f ｐ (P, n) is a product map representing the actual volume (V) in each cylinder (2), and the first map f ｖ (IVC, n) is a function of the intake valve closing retard (IVC) and the engine rotation speed (n), and is calculated using the second map f ｈ (H, n) is a function of the intake valve lift (H) and the engine rotation speed (n), and the third map f ｐ (P, n) is a function of the intake pressure (P) and the engine rotation speed (n), K １ and K. ２ is a multiplication factor that takes into account the angle of intake valve angular displacement (VVT i ), the angle of exhaust valve angular displacement (VVT e ) and the rotational speed (n) of the engine (1), K Ｔ is the temperature (T) detected in the intake manifold (4) and the temperature (T) of the engine coolant Ｈ２Ｏ 37. The method of claim 36, wherein the coefficient is based on

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