GB2535158A

GB2535158A - Method for operating a digital inlet valve

Info

Publication number: GB2535158A
Application number: GB1502090.2A
Authority: GB
Inventors: Nieddu Stefano; Mollar Andrea; Sorrentino Tiziano
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2015-02-09
Filing date: 2015-02-09
Publication date: 2016-08-17
Also published as: CN106907256A; GB201518557D0; GB201502090D0; GB2535266A

Abstract

Disclosed is a method of controlling a digital inlet valve of an internal combustion engine and a valve arrangement. The valve comprises a shutter, valve head 505, moveable between a closed position and an open position, actuated by a linear electromagnetic actuator 530 comprising a movable needle located inside a coil winding 345 connected to a power source 605 by means of a first electronic switch 610. The method provides for supplying an electric current to the coil winding, monitoring a parameter indicative of a movement of the needle, such as the energisation time of the coil, the adjusting the electric current supply when the monitored parameter exceeds a predetermined value. Also disclosed is a valve arrangement comprising a three-way switch. The embodiment relates to a high pressure fuel pump in an internal combustion engine, specifically a Diesel engine.

Description

METHOD FOR OPERATING A DIGITAL INLET VALVE

TECHNICAL FIELD

The present disclosure relates to a circuit and a method for operating a digital inlet valve associated to a high pressure pump provided in an internal combustion engine, in particular a diesel engine.

BACKGROUND

Modern Diesel engines are provided with a fuel injection system which is configured to dispose in a combustion chamber of the engine a metered of fuel.

Fuel injection system comprises a high pressure fuel pump, that increases the pressure of the fuel received from a low pressure pump in fluid communication with a fuel tank, and that delivers the fuel to a fuel rail in fluid communication with a fuel injector disposed within 20 the combustion chamber of the engine.

The high pressure pump is provided with a digital inlet valve for selectively admitting fuel to an inlet conduit of the high pressure pump.

A known digital inlet valve comprises a shutter associated to a shutter seat provided in the inlet conduit of the high pressure pump. The shutter can translate from a closed to an open position in contrast with the action of a compression spring. The translation of the shutter is operated by means of a linear electromagnetic actuator, also known as linear solenoid, which comprises a needle located inside a coil winding. The needle is biased the action of a compression (return) spring towards a lower position, where it contacts the shutter keeping it in the open position.

When an electric current flows through the coil winding it generates a magnetic field that operates the translation of the needle in contrast to the return spring. In this way the needle departs from the shutter allowing the same to move in the closed position where it is received in the shutter seat, preventing the flowing of the fuel.

A drawback of the disclosed digital inlet valve is due to the noise generated during its operation. In detail the noise is due to the operation of the shutter and the needle during the closing and the opening phases of the inlet valve.

In view of the above, an object of an embodiment of the present invention is to reduce the operating noise of the digital inlet valve.

Another object is that of accomplish the above-mentioned goals with a simple, rational and rather inexpensive solution.

SUMMARY

These and other objects are achieved by the embodiments of the invention as defined in the independent claims. The dependent claims include preferred and/or advantageous aspects of said embodiments.

More particularly, an embodiment of the invention provides for operating a digital inlet valve provided with a shutter, moveable between a closed and an open position, actuated by a linear electromagnetic actuator comprising a movable needle located inside a coil winding connected to a power source by means of a first electronic switch, the method provides for a) supplying an electric current to the coil winding, b) monitoring a parameter indicative of a movement of the needle, c) adjusting the electric current supply when the monitored parameter exceeds a predetermined value.

Thanks to this solution, it is possible to regulate the translation speed of the needle and of shutter, slowing the translation speed near the end stops. A slow speed will reduce the noise generated by the impact of the needle or of the shutter against the end stops. According to an aspect of the invention, the parameter indicative of a movement of the needle is a conduction time interval of the first electronic switch.

This aspect if the invention provides a reliable and easy way to determine a movement of the needle.

According to an aspect of the invention, the adjustment of the electric current provides for: a) interrupting the electric current supply, b) connecting the coil winding to a dissipative bi-pole for discharging the electric current from the coil winding.

This aspect of the invention allows a faster slowing of the needle speed.

According to an aspect of the invention, the parameter indicative of a movement of the needle is an interdiction time of the electronic switch.

According to an aspect of the invention, the adjustment of the electric current provides for increasing the supplied electric current value.

This aspect of the invention allows a faster slowing down of the shutter speed.

A different embodiment of the invention provides for a digital inlet valve comprising: a) a shutter, moveable between a closed and an open position, b) a linear electromagnetic actuator, for actuating the shutter, comprising a movable needle located inside a coil winding having a first and a second end terminal, c) a control circuit connected to the first and the second end terminals, comprising a first, a second and a third electronic switches, wherein the first end terminal is electrically connected to a power source by means of the 5 first electronic switch, and to a ground pole by means of the second electronic switch, and the second end terminal is electrically connected to the third electronic switch, which can switches in three different position, a first position wherein the second end terminal is directly connected to the ground pole, a second position wherein the second end terminal is connected to the ground pole by means of a dissipative bi-pole, and a third position 10 wherein the second end terminal is not connected to the ground pole, the first and the third electronic switch being connected to an electronic control unit configured to command the first electronic switch to an open position disconnecting the electric power source and to command the third electronic switch in the second position when a conduction time of the first electronic switch exceeds a predetermined value.

This embodiment has the advantage to provide a reliable and cheap control circuit.

According to an aspect of the invention, the shutter and the needle are made in a single body.

This aspect of the invention is an economic alternative to the previous embodiment.

A different embodiment of the invention provides for a high pressure pump for supplying fuel to a rail of an internal combustion engine comprising a digital inlet valve according to the previous aspects of the invention.

The method of the invention can be carried out with the help of a computer program comprising a program-code for carrying out all the steps of the method described above, and in the form of a computer program product comprising the computer program. The 25 method can be also embodied as electromagnetic signals, said signal being modulated to carry a sequence of data bits which represent a computer program to carry out all steps of the method.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, with reference to the accompanying drawings.

Figure 1 schematically shows an automotive system belonging to a motor vehicle.

Figure 2 is the section A-A of an internal combustion engine belonging to the automotive system of figure 1.

Figure 3, 3a, 3b, 3c are schematic sections, according a vertical plane, of a high pressure pump and a digital inlet valve in different operating positions.

Figure 4a, 4b illustrates a control circuit according to an embodiment of the invention. Figure 5a,5b,6a,6b show the variation over time of some signals used in an embodiment invention.

Fig.7 is a schematic section, according a vertical plane, of a high pressure pump and a digital inlet valve in different operating positions of a different embodiment of the invention.

DETAILED DESCRIPTION

Some embodiments may include an automotive system 100, as shown in Figures 1 and 2, that includes an internal combustion engine (ICE) 110 having an engine block 120 defining at least one cylinder 125 having a piston 140 coupled to rotate a crankshaft 145. A cylinder 20 head 130 cooperates with the piston 140 to define a combustion chamber 150.

A fuel and air mixture (not shown) is disposed in the combustion chamber 150 and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston 140. The fuel is provided by at least one fuel injector 160 and the air through at least one intake port 210. The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 in fluid communication with a high pressure fuel pump 180 that increase the pressure of the fuel received from a fuel source 190. Each of the cylinders 125 has at least two valves 215, actuated by a camshaft 135 rotating in time with the crankshaft 145. The valves 215 selectively allow air into the combustion chamber 150 from the port 210 and alternately allow exhaust gases to exit through a port 220. In some examples, a cam phaser 155 may selectively vary the timing between the camshaft 135 and the crankshaft 145.

In the combustion chamber 150 is located a glow plug 360 which is a heating element which is electrically activated for cold starting of the engine and also for improving the combustion performance within the combustion chamber.

The air may be distributed to the air intake port(s) 210 through an intake manifold 200. An air intake duct 205 may provide air from the ambient environment to the intake manifold 200. In other embodiments, a throttle body 330 may be provided to regulate the flow of air into the manifold 200. In still other embodiments, a forced air system such as a turbocharger 230, having a compressor 240 rotationally coupled to a turbine 250, may be provided. Rotation of the compressor 240 increases the pressure and temperature of the air in the duct 205 and manifold 200. An intercooler 260 disposed in the duct 205 may reduce the temperature of the air. The turbine 250 rotates by receiving exhaust gases from an exhaust manifold 225 that directs exhaust gases from the exhaust ports 220 and through a series of vanes prior to expansion through the turbine 250. This example shows a variable geometry turbine (VGT) with a VGT actuator 290 arranged to move the vanes to alter the flow of the exhaust gases through the turbine 250. In other embodiments, the turbocharger 230 may be fixed geometry and/or include a waste gate.

The exhaust gases exit the turbine 250 and are directed into an exhaust system 270. The exhaust system 270 may include an exhaust pipe 275 having one or more exhaust aftertreatment devices 280. The aftertreatment devices may be any device configured to 25 change the composition of the exhaust gases. Some examples of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters. Other embodiments may include an exhaust gas recirculation (EGR) system 300 coupled between the exhaust manifold 225 and the intake manifold 200. The EGR system 300 may include an EGR cooler 310 to reduce the temperature of the exhaust gases in the EGR system 300. An EGR valve 320 regulates a flow of exhaust gases in the EGR system 300.

The automotive system 100 may further include an electronic control unit (ECU) 450 in communication with one or more sensors and/or devices associated with the ICE 110. The ECU 450 may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE 110. The sensors include, but are not limited to, a mass airflow and temperature sensor 340, a manifold pressure and temperature sensor 350, a combustion pressure sensor that may be integral within the glow plugs 360, coolant and oil temperature and level sensors 380, a fuel rail pressure sensor 400, a cam position sensor 410, a crank position sensor 420, exhaust pressure and temperature sensors 430, an EGR temperature sensor 440, and an accelerator pedal position sensor 445. Furthermore, the ECU 450 may generate output signals to various control devices that are arranged to control the operation of the ICE 110, including, but not limited to, the fuel injectors 160, the throttle body 330, the EGR Valve 320, the VGT actuator 290, and cam phaser 155 and the glow plug 360. Note, dashed lines are used to indicate communication between the ECU 450 and the various sensors and devices, but some are omitted for clarity.

Turning now to the ECU 450, this apparatus may include a digital central processing unit (CPU) in communication with a memory system and an interface bus. The CPU is 25 configured to execute instructions stored as a program in the memory system 460, and send and receive signals to/from the interface bus. The memory system 460 may include various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analog and/or digital signals to/from the various sensors and control devices.

The program may embody the methods disclosed herein, allowing the CPU to carryout out the steps of such methods and control the ICE 110.

The program stored in the memory system 460 is transmitted from outside via a cable or in a wireless fashion. Outside the automotive system 100 it is normally visible as a computer program product, which is also called computer readable medium or machine readable medium in the art, and which should be understood to be a computer program code residing on a carder, said carrier being transitory or non-transitory in nature with the consequence that the computer program product can be regarded to be transitory or non-transitory in nature.

An example of a transitory computer program product is a signal, e.g. an electromagnetic signal such as an optical signal, which is a transitory carrier for the computer program code. Carrying such computer program code can be achieved by modulating the signal by a conventional modulation technique such as QPSK for digital data, such that binary data representing said computer program code is impressed on the transitory electromagnetic signal. Such signals are e.g. made use of when transmitting computer program code in a wireless fashion via a WiFi connection to a laptop.

In case of a non-transitory computer program product the computer program code is embodied in a tangible storage medium. The storage medium is then the non-transitory carrier mentioned above, such that the computer program code is permanently or non-permanently stored in a retrievable way in or on this storage medium. The storage medium can be of conventional type known in computer technology such as a flash memory, an Asic, a CD or the like.

The high pressure pump 180 (Figure 3) comprises, inside a cylinder 181, a plunger 182 which can translate in an axial direction being actuated by a cam 183. According to this embodiment of the invention the cam 183 is associated to the camshaft 135 rotating in 5 time with the crankshaft 145.

A cylinder head 184 cooperates with the cylinder 181 and the plunger 182 to define a fuel pumping chamber 185 provided with a fuel inlet 186, located in the cylinder head 184, and a fuel outlet 187, located on the cylinder 181. The fuel inlet 186 is in fluid communication with the fuel source 190 and the fuel outlet 187 is fluid communication with the fuel rail 170.

A digital inlet valve 500 cooperates with the high pressure pump 180 for supplying fuel inside the pumping chamber 185.

The digital inlet valve 500 comprises a shutter 505 associated to a shutter seat 188, provided in cylinder head 184, and in fluid communication with the inlet conduit 186 of the high pressure pump 180. The shutter 505 is provided with a shaft 510 received in a central bore 515 located in a bottom wall 520 of a valve housing 525.

The shutter 505 can axially translate between a closed position, wherein it is received in the shutter seat 188 preventing fuel flowing, and an open position, wherein it is spaced apart from the shutter seat 188, allowing the fuel flowing.

The axial translation of the shutter 505, from the closed to the open position, is operated by means of a linear electromagnetic actuator 530, also known as linear solenoid in contrast with the action of a first compression spring 535 associated to the shaft 510.

In detail the first compression spring 535 acts between the bottom wall 520 and a spring guide 536 connected to the shaft 510.

The linear electromagnetic actuator 530 is placed inside the valve housing 525 and it comprises a needle 540, located inside a coil winding 545, that can translate in contrast to the action of a second compression spring 550.

According to the present embodiment of the invention the second compression spring 550 is inserted externally and coaxially on the needle 540 and it acts between a support body 5 555 of the coil winding 545 and a spring guide 560 connected to the needle 540.

Furthermore the valve housing 525 is provided with a valve fuel inlet 565 in fluid communication with the fuel inlet 186 on the cylinder head 184.

A second embodiment of the invention provides that the shutter 505 and the needle 540 are made in a single body 700 as shown in Fig. 7, wherein the same referral numbers have been used to indicate identical components already disclosed in the previous embodiment of the invention. This second embodiment provides only a compression spring 705 inserted externally and coaxially on the needle 540 and acting between a support body 555 of the coil windings 545 and a spring guide 560 connected to the needle 540.

The digital inlet valve 500 comprises also a control circuit 600 of the linear actuator 530 which is connected to a first and a second end terminal 575, 580 of the coil winding 545. The control circuit 600 comprises a first and a second electronic switch 610 and 620 electrically connected to a first end terminal 575 of the coil winding 545, and a third electronic switch 630 electrically connected a the second end terminal 580 of the coil winding 545.

In detail, the first end terminal 575 is electrically connected to a power source 605 by means of the first electronic switch 610, and to a ground pole 640 by means of the second electronic switch 620, while the second end terminal is connected to the third electronic switch 630.

The first electronic switch 610 can switch between a closed position, wherein the first end 25 terminal 575 is electrically connected to the power source 605, and an open position, wherein the first end terminal 575 is not electrically connected to the power source 605. The third electronic switch 630 can switch in three different position, a first position 630a wherein the second end terminal 580 is directly connected to the ground pole 640, a second position 630b, wherein the second end terminal is connected to the ground pole 640 by means of a dissipative bi-pole 650, and a third position 630c, wherein the second end terminal 580 is not connected to the ground pole 640.

According to the present embodiment of the invention the first and the third electronic switches 610,630 are metal-oxide-semiconductor field-effect (MOS-FET) transistors, while the second electronic switches 620 is a diode. The dissipative bi-pole 650 is realized by operating the third electronic switch 630 in the saturation region.

The first and the third electronic switch 610, 630 are connected and controlled to the electronic control unit 450, which is configured to operate the digital inlet valve 500 by means of the control circuit 600, as it will be disclosed in the following.

More in detail, the ECU 450 drives the switching of the first electronic switch 610 from the closed position to the open position when the current value flowing through the control circuit 600 is equal to a predetermined high electric current value IH and it drives the switching of the first electronic switch 610 from the open position to the closed position when the current value flowing through the circuit is equal to a predetermined low electric current value IL.

The predetermined high electric current value IH and the predetermined low electric current value IL are regulated by the ECU according to an angular position of the camshaft 135. According to an embodiment of the invention, the ECU 450 is configured to determine the fuel quantity to be delivered, by the high pressure pump 180 to the rail 170, as a function of an actual operating condition of the engine, and to determine, on the basis of the calculated required fuel quantity, an opening and a closing instant of the digital inlet valve 500 as a function of an angular position of the camshaft 135.

Fig. 3 shows the digital inlet valve 500 during a fuel suction phase of the high pressure pump 180, wherein the shutter is motionless. During the fuel suction phase the axial translation of plunger 182 generates a depression in the pumping chamber 185 which helps the flowing of the fuel within the pumping chamber 185. In this situation the ECU commands the third electronic switch 630 to stay in the third position 630c, wherein the second end terminal 580 is not connected to the ground pole 640, and it commands the first electronic switch 610 to stay in the open position so that the actuator is not activated and the elastic force of second compression spring 550 concurs to hold the shutter 505 in the open position.

When the angular position of the camshaft 135 corresponds to the determined closing instant of the digital inlet valve 500, the ECU 450, in order to allow the shutter translation from the open to the closed position, commands the periodical switching of the third electronic switch 630 from the third position 630c to the first position 630a, wherein the second end terminal 580 is directly connected to the ground pole 640, and it commands the switching of the first electronic switch 610 between the open and the closed position connecting the coil winding 545 to the power source 605.

As told above, the ECU 450 drives the switching of the first electronic switch 610 from the closed position to the open position when the current value flowing through the control circuit 600 is equal to a predetermined high electric current value IH and it drives the switching of the first electronic switch 610 from the open position to the closed position when the current value flowing through the circuit is equal to a predetermined low electric current value IL.

The driving of the first and third switch 610,630 allows the flowing, through the circuit 600, 25 of an electric current which value is monitored by the ECU 450 by means of a shunt resistor 750.

In this situation, wherein the shutter 505 is still motionless, the coil winding 545 can be electrically represented by means of an inductor 546, having an inductance value L, in series with a resistor 547, having a resistance value R, as illustrated in Fig. 4a.

The electric current flowing through the circuit has a waveform as indicate in the tract A of fig. 5a.

The flowing of an electric current through the coil winding 545 generates a magnetic field inducing a mechanical force on the needle of the actuator 530 in contrast to the elastic force exercised by the second compression spring 550.

The value of the mechanical force acting on the needle 540 is a function of the electric current value flowing through the coil winding 545, therefore the ECU, during the closing phase of the shutter 505, regulates the predetermined high electric current and the predetermined low electric electric current at values IH,IL that guarantee that the electric current flowing through the winding 545 generates a magnetic field inducing a mechanical force on the needle 540 sufficient to win the elastic force exercised by the second compression spring 550, so to allow an upwards translation of the needle, as shown in Fig. 3a The upwards translation of the needle 540 generates a counter electromagnetic force opposing the needle translation.

In this condition the coil winding 545 can be electrically represented by means of the inductor 546 in series with the resistor 547 and a counter electromagnetic force generator 548 as illustrated in Fig. 4b.

The counter electromagnetic force varies the conduction time (Fig.5a tract B) of the first electronic switch 610, i.e. the time interval wherein the first electronic switch 610 is in the closed position, which can be calculated with the following formula: L (V -E -Rh\ Ion iv In V -E -Rid wherein L and R are respectively the inductance and the resistance values of the coil winding, V is the voltage value of the power source, IL and IH are the values respectively of the two predetermined low and high electric current, and E is the value of the counter-electromotive force generated by the movement of the needle 540.

According to the present embodiment of the invention, the ECU 450, which monitors the variation over time of the current flowing through the control circuit 600, determines also the conduction time value TON of the first electronic switch 610, and uses the conduction time value TON as a parameter indicative of a movement of the needle 540.

As soon as the conduction time value exceeds a predetermined value TON, the ECU 450 commands the switching of the first electronic switch 610 from the closed to the open position, interrupting the electric connection of the coil winding 540 with the power source 605, and it also commands the switching of the third switch 630 from the first position 630a to the second position 630b, wherein the second end terminal 580 is connected to the ground pole 640 by means of the dissipative bi-pole 650.

According to an aspect of the invention the predetermined value TON is equal to a conduction time of the first electronic switch 610 while the needle is motionless, and it is 20 determined by ECU 450 monitoring the variation over time of the current flowing through the control circuit 600.

With reference to the control circuit 600 of Fig. 5a, the conduction time of the first electronic switch 610 while the needle is motionless can be calculated with the following formula: -RIL\ TON = -11-X In (V R -Rid wherein L and R are respectively the inductance and the resistance values of the coil winding, V is the voltage value of the power source, IL and IH are the values respectively of the two predetermined low and high electric current.

Thanks to the dissipative bi-pole 650 the current flowing through the coil windings 545 run rapidly out, so as the electromagnetic force acting on the needle. In this way the translation speed of the needle is slowed down and the noise, caused by the impact of the needle against an upper end stop 590, is reduced.

At the same time the shutter 505 translates in the closed position thanks to the action of 10 the first compression spring 530 and to the action of the compression force due to the increasing pressure in the fuel pumping chamber 185 (Fig.3b).

Afterwards the ECU 450 commands the switching of the third electronic switch 630 from the second position 630b to the first position 630a, wherein the second end terminal 580 is directly connected to the ground pole 640, and it commands the switching of the first electronic switch 610 between the open and the closed position connecting the coil winding 545 to the power source 605. The ECU 540 also regulates the predetermined high electric current and the predetermined low electric current at values IH, IL that guarantee that the electric current flowing through the coil winding 545 generates a magnetic field inducing a mechanical force on the needle 540 having a value lower than the elastic force value exercised by the second compression spring 550, allowing a downwards translation of the needle 540 towards the shutter 505 at a low speed, so to reduce the noise generated by the impact of the needle 540 against the shutter 505. (Fig.3c) Once the needle 540 abuts against the shutter 505 the ECU 450 commands the third electronic switch 630 to switch in the third position 630c, wherein the second end terminal 25 580 is not connected to the ground pole 640, and it commands the first electronic switch 610 to switch in the open position so that the linear actuator 530 is not activated.

When the angular position of the camshaft 135 corresponds to the determined opening instant of the digital inlet valve 500, the ECU 450 commands the switching of the third electronic switch 630 from the third position 630c to the first position 630a, wherein the second end terminal 580 is directly connected to the ground pole 640, and it commands the switching of the first electronic switch 610 between the open and the closed position connecting the coil winding to the power source 605.

The ECU 450 also regulates the predetermined high electric current IH and the predetermined low electric current IL at values that guarantee that the electric current flowing through the coil winding 545 generates a magnetic field inducing a mechanical force on the needle 540 having a value lower than the elastic force value exercised by the second compression spring 550, in order to exercise on the needle 540 a force supporting the shutter translation from the closed to the open position.

As soon as the shutter 505 and the needle 540 translate, a counter electromagnetic force, opposing the needle translation, is generated.

The counter electromagnetic force varies the interdiction time value of the first electronic switch 610, and the ECU 450, as soon as the interdiction time value exceeds a predetermined value, regulates, by increasing, the predetermined high electric current and the predetermined low electric current at values IH,IL that guarantee that the electric current flowing through the coil winding generates a magnetic field inducing a mechanical force on the needle 540 sufficient to counterbalance the elastic force exercised by the second compression spring 550.

In this way the translation speed of the shutter 505 is slowed and the noise, caused by the impact of the spring guide 536 against the bottom wall 520 of the valve body 525, is 25 reduced.

With reference to the circuit of fig. 4b the interdiction time of the first electronic switch 610, i.e. the time interval wherein the first electronic switch is in the open position, can be determined with the following formula: TOFF = L R E X In + wherein L and R are respectively the inductance and the resistance values of the coil winding 545, IL and IH are the values the predetermined high and low electric current, and E is a value of the counter-electromotive force generated by the movement of the needle.

As soon as the interdiction time value exceeds a predetermined value TOFF, the ECU operates the control circuit 600 according to the above disclosure.

According to an aspect of the invention, the predetermined value TOFF is equal to an interdiction time of the first electronic switch 610 while the needle is motionless, is determined by ECU 450 monitoring the variation over time of the current flowing through the control circuit 600.

With reference to the control circuit 600 of Fig. 5a, the interdiction time of the first electronic switch 610 while the needle is motionless can be calculated with the following formula: Ton, = X In wherein L and R are respectively the inductance and the resistance values of the coil winding 545, IL and IH are the values the predetermined high and low electric current. While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

REFERENCES

100 motor vehicle automotive system internal combustion engine engine block cylinder 130 cylinder head camshaft piston crankshaft 147 gearbox 148 clutch combustion chamber cam phaser fuel injector fuel rail 180 fuel pump 181 cylinder 182 plunger 183 cam 184 cylinder head 185 fuel pumping chamber 186 fuel inlet 187 fuel outlet 188 shutter seat fuel source 200 intake manifold 205 air intake pipe 210 intake port 215 valves 220 exhaust port 225 exhaust manifold 230 turbocharger 240 compressor 250 turbine 260 intercooler 270 aftertreatment system 275 exhaust pipe 290 VGT actuator 300 exhaust gas recirculation system 305 EGR conduit 310 EGR cooler 320 EGR valve 330 throttle body 340 mass airflow and temperature sensor 350 manifold pressure and temperature sensor 360 glow plug 365 glow plug free end 370 ground pole 380 coolant and oil temperature and level sensors 400 fuel rail pressure sensor 410 cam position sensor 420 crank position sensor 430 speedometer 440 EGR temperature sensor 445 accelerator pedal position sensor 450 ECU 460 memory system 500 digital inlet valve 505 shutter 510 shaft 515 central bore 520 bottom wall 525 valve housing 530 linear electromagnetic actuator 535 compression spring 536 spring guide 540 needle 545 coil winding 550 compression spring 555 support body 560 spring guide 565 fuel inlet 575 terminal 580 terminal 600 control circuit 605 power source 610 electronic switch 620 electronic switch 630 electronic switch 630a first position 630b second position 630c third position 640 ground pole 650 dissipative bi-pole 700 single body 705 compression spring 750 shunt resistor

Claims

CLAIMS1. A method for operating a digital inlet valve (500) provided with a shutter (505), moveable between a closed and an open position, actuated by a linear electromagnetic actuator (530) comprising a movable needle (540) located inside a coil winding (545) connected to a power source (605) by means of a first electronic switch (610), the method provides for: a) supplying an electric current to the coil winding (545), b) monitoring a parameter indicative of a movement of the needle (MO), c) adjusting the electric current supply when the monitored parameter exceeds a predetermined value.
2. A method according to claim 1, wherein the parameter indicative of a movement of the needle (540) is a conduction time of the first electronic switch (610).
3. A method according to claim 1, wherein the adjustment of the electric current provides for: a) interrupting the electric current supply, b) connecting the coil winding (545) to a dissipative bi-pole (650) for discharging the electric current from the coil winding (545).
4. A method according to claim 1, wherein the parameter indicative of a movement of the needle is an interdiction time of the first electronic switch (610).
5. A method according to claim 1, wherein the adjustment of the electric current provides for increasing the supplied electric current value.
6. A digital inlet valve comprising: a) a shutter (505), moveable between a closed and an open position, b) a linear electromagnetic actuator (530), for actuating the shutter (505), comprising a movable needle (MO) located inside a coil winding (545) having a first and a second end terminal (575,580), c) a control circuit (600) connected to the first and the second end term inals(575,580), comprising a first, a second and a third electronic switches (610,620,630), wherein the first end terminal (575) is electrically connected to a power source (605) by means of the first electronic switch (610), and to a ground pole (640) by means of the second electronic switch (620), and the second end terminal (580) is electrically connected to the third electronic switch (630), which can switches in three different position, a first position (630a) wherein the second end terminal is directly connected to the ground pole (640), a second position (630b) wherein the second end terminal is connected to the ground pole by means of a dissipative bi-pole (650), and a third position (630c) wherein the second end terminal is not connected to the ground pole (640), the first and the third electronic switches (610,630) being connected to an electronic control unit (450) configured to command the first electronic switch (610) to an open position disconnecting the electric power source (605) and to command the third electronic switch (630) in the second position (630b) when a conduction time of the first electronic switch (610) exceeds a predetermined value.
7. A digital inlet valve according to claim 6, wherein the shutter (505) and the needle (540) are made in a single body (700).
8. An high pressure pump (180) for supplying fuel to a rail of an internal combustion engine provided with a digital inlet valve (500) according to any of the preceding claims 6 and 7.
9. A computer program comprising a computer-code for performing the method according to any claim from 1 to 5.
10. Computer program product on which the computer program according to claim 9 is stored.

ii. An electromagnetic signal modulated as a carrier for a sequence of data bits representing the computer program according to claim 9.