IT201900010059A1 - SYSTEM AND METHOD OF CONTROL OF A DOSING SOLENOID VALVE IN A PUMPING GROUP TO FEED FUEL TO AN INTERNAL COMBUSTION ENGINE - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

"SYSTEM AND METHOD OF CONTROL OF A DOSING SOLENOID VALVE IN A PUMPING GROUP TO FEED FUEL TO AN INTERNAL COMBUSTION ENGINE"

The present invention relates to a control system and method of a metering solenoid valve in a pumping unit for supplying fuel to an internal combustion engine.

In particular, the present solution relates to a pumping unit of the type comprising a high pressure pump, for example a piston pump, suitable for feeding fuel, for example diesel oil, to an internal combustion engine; a low pressure pre-feed pump, for example a gear pump, adapted to feed the fuel from a containment tank to the high pressure pump; and a hydraulic circuit to connect together the containment tank, the pre-feed pump, the high pressure pump, and the internal combustion engine.

The hydraulic circuit includes a dosing solenoid valve (generally known as FMU, from the English "Fuel Metering Unit", or ZME, from the German "Zumesseinheit") designed to control the instantaneous flow of fuel fed to the high pressure pump, according to the values of a plurality of operating parameters of the internal combustion engine.

The dosing solenoid valve includes a valve body, mounted along the hydraulic circuit, and a shutter engaged in a sliding manner in the valve body to move between an open position and a closed position.

Known pumping units of the type described above have some drawbacks mainly deriving from the fact that the pressure waves generated following the escape of fuel from the cylinders of the high pressure pump can interfere with the control of the shutter of the aforesaid metering solenoid valve, compromising in this way the supply of the correct fuel flow to the same high pressure pump and, therefore, to the internal combustion engine.

The purpose of the present invention is to provide an improved control solution of the dosing solenoid valve of the pumping unit, which allows to overcome the drawbacks described above and which is simple and economical to implement.

According to the present invention, a control system and method are provided, as claimed in the attached claims.

The present invention will now be described with reference to the attached drawings, which illustrate a non-limiting example of embodiment, in which:

Figure 1 is a hydraulic diagram of a pumping unit for feeding fuel to an internal combustion engine;

Figure 2 is a schematic sectional view, with parts removed for clarity, of a portion of the pumping unit of Figure 1, including a relative metering solenoid valve;

- Figure 3 shows an excitation signal from an electromagnetic actuator of the dosing solenoid valve of the pumping group;

- Figure 4 shows a possible trend of the average value and the amplitude of oscillation of the aforementioned excitation signal;

Figure 5 shows the average value of the excitation signal of Figure 4 and an associated trend of the fuel flow in the pumping group;

- Figure 6 shows a possible trend of pressure peaks of the fuel supplied, as a function of the average value of the aforesaid excitation signal;

- Figure 7 shows the trend of the excitation signal generated in accordance with a control scheme according to an aspect of the present solution;

- Figure 8 shows the trend of the amplitude of oscillation and the average value of the excitation signal of Figure 7;

- Figure 9 is a schematic block diagram of an electronic control unit of the dosing solenoid valve according to one aspect of the present solution;

- Figure 10 shows a first embodiment of a driving module of the electronic control unit of Figure 9;

- Figure 11 shows a second embodiment of the driving module of the electronic control unit of Figure 9; And

- Figure 12 is a schematic block diagram of a variant of the electronic control unit of the dosing solenoid valve, according to a further aspect of the present solution.

Figure 1 shows a pumping unit, indicated as a whole with 1, for feeding fuel, for example diesel, from a tank 2 to an internal combustion engine 3, for example a Diesel internal combustion engine. The engine 3 comprises a fuel distribution manifold 4, commonly referred to with the term "common rail", and a plurality of injectors 5 connected to the manifold 4 and adapted to nebulize the fuel inside the relative combustion chambers (here not illustrated).

The pumping unit 1 comprises a high pressure pump 6, in particular a piston pump, for supplying fuel to the engine 3; and a low pressure pump 7, or a pre-feed pump, in particular a gear pump, for example electrically operated, for feeding the fuel from the tank 2 to the high pressure pump 6.

The high pressure pump 6 comprises a pump body 8 and, in the illustrated example, two cylinders 9, obtained in the pump body 8 and having respective longitudinal axes 10 substantially parallel to each other.

The cylinders 9 are engaged in a sliding manner by respective pistons 11, movable under the thrust of an actuation device 12, with a reciprocating rectilinear motion comprising an intake stroke of the fuel in the relative cylinders 9 and a stroke of delivery of the fuel to the engine 3 .

The actuation device 12 comprises a cam transmission shaft 13, housed in a first containment chamber 14 obtained in the pump body 8, and is adapted to move the pistons 11 with their delivery stroke.

The actuation device 12 also comprises, for each piston 11, a respective spring (not shown), which is housed in a second containment chamber (not shown) obtained in the pump body 8 and is adapted to move the piston 11 itself. with its suction stroke. In particular, the shaft 13 is configured in such a way as to simultaneously move a piston 11 with its suction stroke and the other piston 11 with its delivery stroke.

The pumping unit 1 further comprises a hydraulic circuit 15 comprising, in turn: a first branch 16 for connecting the tank 2 and the low pressure pump 7 together; a second branch 17 for connecting the low pressure pump 7 and the high pressure pump 6 together; and a third branch 18 to connect the high pressure pump 6 and the manifold 4 together.

The second branch 17 is provided with a filtering device 19 to filter the fuel fed to the cylinders 9, and also has a metering solenoid valve 20 (usually called 'FMU' or 'ZME'), mounted downstream of the filtering device 19 in a direction 21 of advancement of the fuel along the same second branch 17.

The metering solenoid valve 20 is operated to control the instantaneous flow rate of fuel fed to the high pressure pump 6 as a function of the values of a plurality of operating parameters of the engine 3; in a possible implementation, to which reference will be made here, the dosing solenoid valve 20 is of the normally open type ("normally ON").

An electronic control unit 100 (equipped with a processing unit with microcontroller, microprocessor or similar digital processing element, coupled to a non-volatile memory, and with a suitable driving stage or "driver") is operatively coupled to the dosing solenoid valve 20, to control its operation on the basis of the aforementioned operating parameters of the motor 3.

Note that this electronic control unit 100 can be operatively coupled to a management and supervision unit (not shown here) of the operation of the motor 3, or be integrated in the aforementioned management and supervision unit of the motor 3.

The second branch 17 and the third branch 18 are connected to each cylinder 9 by means of an intake valve 22 and, respectively, a delivery valve 23.

The aforesaid hydraulic circuit 15 further comprises further circuit branches, having known functions not directly relevant to the present discussion and therefore not described in detail here.

As illustrated in greater detail in Figure 2, the second branch 17 of the hydraulic circuit 15 comprises a supply manifold (or tunnel) 29 and, for each cylinder 9 (not shown here), a respective intake duct 30 to connect the feeding 29 with the same cylinder 9.

The metering solenoid valve 20 comprises a valve body 31 of generically tubular shape, mounted in the supply manifold 29 coaxially to a longitudinal axis 32 of the same supply manifold 29, and has an annular inlet channel 33, which extends around to the longitudinal axis 32, and communicates with the second branch 17 to feed the fuel through the valve body 31.

The valve body 31 is slidably engaged by a shutter 34, having a cup shape, limited axially by a bottom wall 35 substantially perpendicular to the longitudinal axis 32, and is also limited by a substantially cylindrical side wall 36 provided of a plurality of connection holes 37 distributed around the same longitudinal axis 32.

The shutter 34 is movable between an open position, in which the connection holes 37 are radially aligned with the inlet channel 33, and a closed position, in which the same connection holes 37 are axially offset with respect to the inlet channel. 33.

The shutter 34 is moved, and normally maintained, in its open position by a spring 38, interposed between the shutter 34 and a stop ring 39 fixed to a free end of the valve body 31 (it should therefore be noted that the solenoid valve dispenser 20 is of the "normally open" type).

The shutter 34 is moved from its open position to its closed position against the action of the spring 38 by an electromagnetic actuator 40 comprising a cup body 41 blocked on the valve body 31 coaxially to the longitudinal axis 32.

The electromagnetic actuator 40 further comprises an actuation anchor 42, made of ferromagnetic material and slidably mounted inside the cup-shaped body 41. The actuation anchor 42 has a plunger 43, which is engaged in sliding manner in a pair of guides 44 and is arranged in contact with the bottom wall 35.

The electromagnetic actuator 40 further comprises an electric circuit 45, consisting of a coil which extends around the drive anchor 42 and along the longitudinal axis 32 and is electrically powered to move the drive anchor 42 against the spring action 38.

In particular, the aforesaid control unit 100 is operatively coupled to the electric circuit 45 and is configured so as to supply suitable driving signals Sd to the same electric circuit 45 to excite the coil and control the actuation anchor 42 and therefore the opening. and closing of the metering solenoid valve 20, in order to regulate the quantity of fuel supplied to the engine 3.

As previously indicated, pressure fluctuations in the supply manifold 29, which occur due to the leakage of fuel from the cylinders 9 of the high pressure pump 6, cause an instability of the fuel flow to the high pressure pump 6 itself and, of consequently, to engine 3.

In particular, the pressure variations (in particular the pressure peaks in the supply manifold 29) affect the axial balance oscillation of the aforementioned piston 43 of the electromagnetic actuator 40; the resulting effect is that the flow rate supplied by the low pressure pump 7 is not properly regulated, just as the flow of the high pressure pump 6 is not regulated.

The above pressure peaks depend, among other things, on the filling efficiency of the high pressure pump 6 and on the speed (or number of revolutions) of the same high pressure pump 6 (at a higher speed corresponding to a greater instability in the delivery of flow).

In particular, the axial balance of the piston 43 is due to the balance between the magnetic forces (indicated by the solid arrow in the aforementioned Figure 2), originating from the actuation of the electromagnetic actuator 40, and the hydraulic forces (indicated by the dashed arrow in the same Figure 2), associated with the pressure waves in the supply manifold 29.

If the hydraulic forces (for example, due to the effect of the aforementioned pressure peaks) exceed the magnetic force, the axial balance of the piston 43 cannot be correctly controlled, as well as the flow rate, with the consequent onset of instability in the flow of the pump. high pressure 6.

The present Applicant has found that the current control solutions are not sufficiently robust with respect to the disturbances constituted by the aforementioned oscillations of the hydraulic pressure.

In particular, current control solutions provide for an adjustment of the average value of the excitation current in the coil of the electromagnetic actuator 40 by means of a control of the duty cycle of a driving voltage signal in PWM (in pulse width modulation - Pulse Width Modulation ), fixed frequency, supplied to the same electromagnetic actuator 40.

Figure 3 shows a portion of the excitation current signal for the electromagnetic actuator 40, indicated with IZME, in a given time interval. This Figure 3 shows the average value of the IZME excitation signal, and also the peak-to-peak amplitude of the oscillation around the average value, so-called 'ripple amplitude'.

In particular, as previously indicated, the average value of the excitation current determines the flow rate of the supply flow through the dosing solenoid valve 20, while the ripple amplitude determines the oscillation amplitude of the piston 43 of the dosing solenoid valve itself. 20 and therefore the capacity of the magnetic force generated by the IZME excitation signal to oppose the hydraulic disturbing forces, or pressure oscillations, or peaks.

With this control technique, the greater the average value of the excitation current, the greater the ripple amplitude, as shown in Figure 4, which illustrates a ramp trend of the IZME excitation signal, highlighting the increase in the corresponding amplitude of ripple as the average value increases.

It should be noted in particular that, since the dosing solenoid valve 20 is of the normally open type, the maximum flow corresponds to a null excitation current (valve open), while the minimum flow corresponds to a maximum excitation current (valve closed). . High magnetic forces (high excitation current) are therefore reached under partial or reduced pump load conditions (i.e. when the pressure peaks in the supply manifold 29 are lower).

As shown in Figure 5, which shows, in correspondence with the ramp trend of the IZME excitation signal (of which only the average value is shown here), the trend of the pump feed flow, indicated with F, the combination between High pressure spikes and low amplitude of current can lead to instability of the pump flow.

In particular, in the aforementioned Figure 5 an area of instability in the control of the metering solenoid valve 20 is highlighted (within the circled portion of the graph), in which the magnetic force generated is not sufficient to control the pressure oscillations, resulting in an instability in the range.

An aspect of the present solution therefore provides, starting from the aforementioned finding, to appropriately modify the control strategy of the metering solenoid valve 20, to exercise a control action on the value of the ripple amplitude, as well as on the average value of the IZME excitation, in order to obtain sufficient control capacity (as opposed to pressure peaks) in a whole desired working range of the metering solenoid valve 20. In other words, the ripple amplitude is directly controlled by the electronic unit control 100, instead of having a value resulting from the control of the average value of the excitation signal IZME (as occurs in known solutions).

In a possible embodiment, the reference value (or set-point) of the ripple amplitude for the control can have a constant value, appropriately chosen in such a way as to obtain the aforementioned sufficient capacity to oppose pressure peaks. .

In a preferred embodiment, the ripple amplitude value is variable and controlled in a desired manner, in particular on the basis of a trend of the pressure peaks, in such a way as to determine an optimized ripple amplitude value on the basis of the corresponding value of the disturbing hydraulic forces.

In this regard, Figure 6 shows a possible trend of the pressure peaks in the supply manifold 29, as a function of the average value of the excitation signal IZME, for a given speed of the high pressure pump 6. In particular, this trend provides for a strong growth and a relative peak in correspondence with a determined working range of the dosing solenoid valve 20, in this case, for example, between 40% and 60% of the entire working range (considered between the zero value of current and the maximum excitation current value).

Figure 7 shows the corresponding trend of the IZME excitation signal, in accordance with the present control solution; in particular, in this Figure 7 the upper and lower envelope of the same IZME excitation signal are highlighted and the trend of its average value is also highlighted.

Figure 8 shows the trend of the ripple amplitude (considered as the difference between the aforementioned upper and lower envelope) of the IZME excitation signal.

In particular, the ripple amplitude follows, at least in a portion of the operating interval of the dosing solenoid valve 20, the corresponding trend of the pressure peaks, highlighting in fact a corresponding peak, in the example in the portion between 40% and 60% of the entire working range. Outside this portion of the working range (in particular, for values higher than the average value of the IZME excitation signal), the ripple amplitude trend grows linearly with the average value.

Thanks to this trend, the ripple amplitude is therefore sufficient to counteract the pressure oscillations (ensuring a magnetic force equal to or greater than the corresponding hydraulic forces).

The control scheme of the dosing solenoid valve 20, implemented by the relative control unit 100, is now described with reference first to Figure 9.

In particular, the aforementioned control unit 100 comprises a first map module 101, in which a map of the position of the pressure peaks inside the supply manifold 29 is stored, as a function of the average current value of the excitation signal IZME and also of the speed (or number of revolutions) of the high pressure pump 6. This map can be determined on the bench, in a characterization phase of the motor 3 and is stored in the non-volatile memory of the control unit 100, where it is stored also a suitable software program for the implementation of the aforesaid control scheme.

The control unit 100 further comprises a second map module 102, which stores a respective amplitude map of the ripple of the excitation signal IZME, in correspondence with the map of the pressure peaks provided by the first map module 101. Also this map can be determined on the bench, in a characterization step of the motor 3 and stored in the non-volatile memory of the control unit 100.

As previously discussed with reference to Figures 6-8, the second map module 102 returns, for each working point of the metering solenoid valve 20, the value of the ripple amplitude of the excitation signal IZME, such as to balance in a manner the disturbance represented by the pressure peaks present in the supply manifold 29 (having the trend provided by the first map module 101) is desired. For example, the second map module 102 outputs the ripple amplitude based on the trend shown in the aforementioned Figure 8.

The control unit 100 further comprises a driving stage (driver) 104 coupled to the metering solenoid valve 20, configured so as to drive the relative electric circuit 45 (and the relative coil) for the generation of the IZME excitation signal, having in this case both duty cycle and variable frequency.

The driving stage 104, in a first embodiment, which will be described in greater detail below, comprises a driving module 105 which implements a control of the ripple amplitude of the IZME excitation signal.

In a second possible embodiment, shown in the same Figure 9, the same driving stage 104 comprises a third map module 106 and a respective driving module 108 which implements a control of the duty cycle of the excitation signal IZME, having in this case a frequency determined by the aforementioned third map module 106.

This third map module 106 in fact stores a map of the value of the frequency of the excitation signal IZME, as a function of the ripple amplitude value provided by the second map module 102. This map can be determined on the bench, in a phase of characterization of the motor 3 and is stored in the non-volatile memory of the control unit 100. Once the average value of the IZME excitation signal has been set, in fact, the frequency of the IZME excitation signal determines the ripple amplitude of the IZME excitation signal itself (which increases as the frequency decreases).

In greater detail, and as shown in Figure 10, the driving module 105 of the driving stage 104, in the first embodiment, comprises a comparator block with hysteresis 110, which receives at its input an average reference value (or set-point) for the excitation signal IZME (as a function of the desired value of the flow rate of fuel supplied to the high pressure pump 6) and also, as a further reference or control set-point, the desired ripple amplitude value provided by the second map module 102 .

The comparator block with hysteresis 110 also receives at its input, as a feedback for the control action, the actual excitation signal IZME, i.e. the current circulating through the electric circuit 45 of the dosing solenoid valve 20, measured by a suitable sensor coupled to the same dosing solenoid valve 20.

The comparator block with hysteresis 110 generates at its output an impulsive signal Simp (of the ON / OFF type), with a square wave, which has a first value, for example high, when the actual excitation signal IZME is included in the defined amplitude window from the aforementioned average reference value and from the reference ripple amplitude (in particular, the ripple half-amplitude is added / subtracted from the average value), and a second value, for example low, when the actual excitation signal IZME it is outside the same width window.

The driving module 105 further comprises a power block 112, powered by a supply voltage Val, supplied for example by the battery of the motor vehicle, and configured in such a way as to generate a driving signal VPWM, in particular a voltage signal in pulse width modulation, starting from the aforementioned pulse signal Simp generated by the comparator stage with hysteresis 110; this power block 112 can comprise a DC / DC voltage converter, for example of the boost type (of a type known per se, not described in detail here).

The VPWM pilot signal is then supplied to the electrical circuit 45 of the dosing solenoid valve (ZME) 20 with the consequent generation of the IZME excitation signal and the corresponding magnetic force.

As shown in Figure 10, the driving module 105 may further comprise a measurement block 114, which receives the aforementioned actual excitation signal IZME at its input and calculates its average current value. This average value is sent to the input of the aforementioned first map module 101 of the control unit 100 and / or used for further control actions (in a manner not illustrated here), as a feedback signal.

As shown in Figure 11, in the second embodiment, the driving module 108 of the driving stage 104 comprises a control block 120, for example of the PI (Proportional Integral) or PID (Proportional Integral Derivative) type, which receives the value reference average for the IZME excitation signal (indicative of the desired value of the fuel flow supplied to the high pressure pump 6) and also, in feedback, the average current value of the actual IZME excitation signal measured by a measurement block , again indicated with 114, which receives at its input the aforesaid actual excitation signal IZME and calculates its average current value.

The same control block 120 also receives at its input the desired value of the frequency of the excitation signal IZME supplied by the third map module 106 (based on the desired value of the ripple amplitude), and generates at its output the impulsive signal Simp (of ON / OFF type), for the power block, also indicated here with 112; this power block 112 is also powered in this case by the power supply voltage Val and also receives at the input the frequency value provided by the third map module 106.

In particular, the impulsive signal Simp therefore has a frequency equal to the aforementioned frequency value provided by the third map module 106 and duty cycle determined by the feedback control action exerted by the control block 120.

The power block 112 is also in this case configured so as to generate, starting from the aforementioned impulsive signal Simp, the pilot signal VPWM which is supplied to the electrical circuit 45 of the dosing solenoid valve 20.

The advantages of the present solution emerge clearly from the previous description.

In any case, it is again pointed out that the control strategy described allows to appropriately compensate the hydraulic forces due to the pressure peaks in the supply manifold 29 with the magnetic force generated by the metering solenoid valve 20, so as to reduce the flow perturbations due to the high pressure pump 6 (and for the motor 3).

In particular, at full load, the frequency of the IZME excitation signal can advantageously be lower (which means having a higher current ripple amplitude and higher magnetic force peaks), so as to reduce the fluctuation of the flow rate. pump. On the other hand, in conditions of low pump load, a high frequency of the same IZME excitation signal can be used, which is better than the low frequency, because in this case the hydraulic forces are lower and therefore a lower magnetic force is sufficient for the their compensation.

In other words, the control strategy allows to obtain the optimal control solution for each working point, unlike traditional control solutions (fixed frequency and variable duty cycle), thus obtaining a more stable and controlled power supply. fuel.

Finally, it is clear that modifications and variations may be made to what has been described and illustrated without thereby departing from the scope of protection of the present invention, as defined in the attached claims.

In particular, as shown in Figure 12, a further variant can be provided for the control scheme implemented by the control unit 100.

In this case, the first map module 101 is not provided, which stores the map of the position of the pressure peaks inside the supply manifold 29.

The control unit 100 in fact includes: a pressure sensor 130, configured to detect the pressure of the fluid inside the supply manifold 29 and generate a pressure signal SP; and a processing module 131, coupled to the pressure sensor 130 and configured to detect the position and trend of the pressure peaks starting from the analysis of the aforementioned pressure signal SP (an example of which, with the relative peaks highlighted, is shown in the same Figure 12).

In this case, the processing module 131 provides the second map module 102 with the information detected about the "map" (ie the position in time) of the pressure peaks, for the determination, in a manner completely similar to what was previously discussed , of the corresponding value of the ripple amplitude of the excitation signal IZME, such as to balance in a desired manner the disturbance represented by the pressure peaks themselves.

The control unit 100 also comprises in this embodiment the driving stage 104 (not shown here), configured so as to generate and supply the driving signal VPWM to the electric circuit 45 (and to the relative coil) of the solenoid valve. dosage 20 for the generation of the IZME excitation signal; in particular, this driving stage 104 also in this case can be realized according to the first or second embodiment (discussed previously, with reference respectively to Figure 9 and Figure 10).

Furthermore, it should be noted that the aforementioned first map module 101, where present, could receive at its input further parameters indicative of the operating point of the motor 3, in addition to the speed of the pump, including, for example, the injection quantity, the pressure in the common rail ("common rail"), or other relevant quantities.

Claims (17)

CLAIMS 1. Control system of a dosing solenoid valve (20) in a pumping group (1) for supplying fuel to an internal combustion engine (3), the pumping group (1) comprising a high pressure pump (6 ) to supply fuel to the internal combustion engine (3); a pre-feed pump (7) for feeding fuel from a containment tank (2) to the high pressure pump (6); and a hydraulic circuit (15) to connect together the containment tank (2), the pre-supply pump (7), the high pressure pump (6), and the internal combustion engine (3), the circuit hydraulic (15) comprising the metering solenoid valve (20) mounted between the pre-feed pump (7) and the high pressure pump (6); wherein said dosing solenoid valve (20) comprises an electromagnetic actuator (40) and said control system comprises an electronic control unit (100) configured to generate a driving signal (VPWM) for said electromagnetic actuator (40) , in pulse width modulation - PWM, for the generation of a corresponding excitation signal (IZME) and a corresponding magnetic actuation force; said electronic control unit (100) comprising a driving stage (104) configured so as to control the average value of said excitation signal (IZME) on the basis of an average reference value, characterized in that said driving stage (104) is also configured so as to control an oscillation amplitude - ripple - of said excitation signal (IZME) superimposed on said average value, on the basis of an oscillation amplitude value of reference. System according to claim 1, wherein the average reference value of said excitation signal (IZME) is determined on the basis of a desired flow rate of fuel in said hydraulic circuit (15) and the value of said reference oscillation amplitude it is determined on the basis of the trend of pressure oscillations in said hydraulic circuit (15). System according to claim 1 or 2, wherein said excitation signal (IZME) has variable frequency and duty cycle values determined by the control of said average value and said oscillation amplitude by said driving stage (104 ). System according to any one of the preceding claims, wherein said electronic control unit (100) comprises an amplitude map module (102), configured so as to store a trend of the oscillation amplitude of said excitation signal (IZME ), as a function of a corresponding trend of pressure peaks of said fuel in said hydraulic circuit (15); wherein said driving stage (104) is configured to receive said reference oscillation amplitude from said amplitude map module (102). System according to claim 4, wherein said electronic control unit (100) further comprises a pressure map module (101), configured so as to store a map of pressure peaks within the fluidic circuit (15) as a function of an operating point of said metering solenoid valve (20); and in which said amplitude map module (102) is operatively coupled to said pressure map module (101) to receive said pressure peak pattern at the input. System according to claim 4, wherein said electronic control unit (100) further comprises: a pressure sensor (130), configured so as to detect the pressure inside the fluidic circuit (15) and generate a signal of pressure (P); and a processing module (131), coupled to the pressure sensor (130) and configured to detect the trend of pressure peaks starting from the analysis of said pressure signal (P); wherein said amplitude map module (102) is operatively coupled to said processing module (131) in order to receive said trend of the pressure peaks at its input. System according to any one of the preceding claims, wherein said driving stage (104) comprises a driving module (105) configured so as to implement an amplitude control of said excitation signal (IZME); wherein said driving module (105) comprises a comparator block with hysteresis (110), configured in such a way as to receive in input the average reference value of said excitation signal (IZME), said reference oscillation amplitude and also an effective excitation signal (IZME) indicative of the current circulating in the electromagnetic actuator (40), and in such a way as to generate an impulsive signal (Simp) having a first value, when the actual excitation signal (IZME) is included in the window of amplitude defined by said average reference value and by said reference oscillation amplitude, and a second value, when the actual excitation signal (IZME) is outside said amplitude window. System according to claim 7, wherein said driving module (105) comprises a power block (112), powered by a supply voltage (Val) and configured so as to generate the driving signal (VPWM) starting from said impulsive signal (Simp), said driving signal (VPWM) being a voltage signal in pulse width modulation. System according to any one of claims 1-6, wherein said driving stage (104) comprises a frequency map module (106) and a respective driving module (108) which implements a duty cycle control of the driving signal excitation (IZME), said excitation signal (IZME) having a frequency determined by said frequency map module (106); wherein said frequency map module (106) is configured so as to store a map of values of the frequency of the excitation signal (IZME), as a function of the reference oscillation amplitude value. System according to claim 9, wherein said driving module (108) comprises a control block (120), configured in such a way as to receive in input the average reference value of said excitation signal (IZME), the average value current of an effective excitation signal (IZME), indicative of the current circulating in the electromagnetic actuator (40), and the value of the frequency of the excitation signal (IZME) supplied by said third map module (106), and in a way to generate at the output an impulsive signal (Simp) for a power block (112), powered by a power supply voltage (Val) and configured in such a way as to generate a driving signal (VPWM) starting from said impulsive signal (Simp) , said driving signal (VPWM) being a pulse width modulated voltage signal. 11. Pumping group (1) for supplying fuel to an internal combustion engine (3), the pumping group (1) comprising a high pressure pump (6) for supplying fuel to the internal combustion engine (3); a pre-feed pump (7) for feeding fuel from a containment tank (2) to the high pressure pump (6); and a hydraulic circuit (15) to connect together the containment tank (2), the pre-supply pump (7), the high pressure pump (6), and the internal combustion engine (3), the circuit hydraulic (15) comprising a dosing solenoid valve (20) mounted between the pre-feed pump (7) and the high pressure pump (6), further comprising the control system of the dosing solenoid valve (20) according to a any of the preceding claims. Pumping unit according to claim 11, wherein said electromagnetic actuator (40) comprises an electric circuit (45) adapted to be electrically piloted by said pilot signal (VPWM) to move an obturator (34) of said metering solenoid valve (20) from an open position to a closed position. 13. Method of controlling a metering solenoid valve (20) in a pump assembly (1) for supplying fuel to an internal combustion engine (3), the pump assembly (1) comprising a high pressure pump (6 ) to supply fuel to the internal combustion engine (3); a pre-feed pump (7) for feeding fuel from a containment tank (2) to the high pressure pump (6); and a hydraulic circuit (15) to connect together the containment tank (2), the pre-supply pump (7), the high pressure pump (6), and the internal combustion engine (3), the circuit hydraulic (15) comprising the metering solenoid valve (20) mounted between the pre-feed pump (7) and the high pressure pump (6), in which said metering solenoid valve (20) comprises an electromagnetic actuator (40) , comprising: generate a driving signal (VPWM) for said electromagnetic actuator (40), in pulse width modulation - PWM, for the generation of a corresponding excitation signal (IZME) and a corresponding magnetic actuation force, said generating step comprising controlling the average value of said excitation signal (IZME) on the basis of an average reference value, characterized by the fact that said generating phase also comprises controlling an amplitude of oscillation - ripple - of said excitation signal (IZME) superimposed on said average value, based on a reference oscillation amplitude. The method according to claim 13, comprising determining the average reference value of said excitation signal (IZME) based on a desired flow rate of fuel in said hydraulic circuit (15), and the value of said reference oscillation amplitude in based on the trend of pressure oscillations in said hydraulic circuit (15). Method according to claim 13 or 14, comprising memorizing an amplitude map of the oscillation amplitude trend of said excitation signal (IZME), as a function of a corresponding trend of fuel pressure peaks in said hydraulic circuit ( 15); wherein said generating step comprises deriving said reference oscillation amplitude from said amplitude map. Method according to claim 15, wherein said controlling step comprises controlling the amplitude of said excitation signal (IZME), so that it is within an amplitude window defined by said average reference value and said reference oscillation amplitude. Method according to claim 15, wherein controlling comprises controlling a duty cycle of said excitation signal (IZME) on the basis of said average reference value, and controlling the frequency of said excitation signal (IZME) on the basis of said amplitude of reference oscillation.