DESCRIPTION

Field of application

[0001]The present invention relates to a valve group for a diesel fuel filtration module of a vehicle. Furthermore, the present invention relates to a diesel fuel filtration module comprises said valve group.

Background art

[0002]It is well known that in a diesel-powered vehicle there is at least one filtering module for the filtration of the diesel fuel itself.

[0003]It is also known that diesel fuel filtration operations are performed only when specific conditions occur, in particular, when specific temperature ranges occur. For example, diesel fuel filtering modules are known comprising electric heaters suitable for heating the diesel fuel in filtration.

[0004]In particular, in low temperature conditions, the filter group operates in non-ideal conditions, due to the formation of paraffin crystals which cause the filter group to become clogged, preventing the diesel fuel access to the engine.

[0005]A conventional issue encountered in the solutions of the prior art is therefore not performing a correct and timely detection of the diesel fuel temperature, in particular in the filtration chamber, failing to perform a correct and precise regulation of the quantity of diesel fuel which must reach said filtration chamber. Solution of the invention

[0006]The need is therefore strongly felt to provide a valve group which solves the aforesaid technical problem. [0007]The purpose of the present invention is to provide a valve group which effectively detects the temperature of the diesel fuel in the filtration chamber and, at the same time, which regulates the quantity of diesel fuel flowing towards said filtration chamber in a correct and precise manner.

[0008]Such purpose is achieved by means of the valve group claimed in claim 1 and by means of the diesel fuel filtration module according to claim 15. The claims dependent thereon show preferred variants of realization implying further advantageous aspects.

Description of the drawings

[0009]Further features and advantages of the invention will appear from the following description of preferred examples of embodiments thereof, provided by way of a non-limiting example, with reference to the accompanying figures, wherein:

[0010]- Figure 1 shows a front view of a diesel fuel filtration module according to a preferred embodiment according to the present invention;

[0011]- Figure la shows a sectional view along the section plane X-X referred to in Figure 1;

[0012]- Figure 2 shows a partially sectioned front view of a diesel fuel filtration module in accordance with a preferred embodiment according to the present invention;

[0013]- Figure 2a shows a sectional view along the section plane XI-XI referred to in Figure 2;

[0014]- Figure 3 shows a sectional view of a diesel fuel filtration module comprising a valve group according to the present invention configured in a low temperature configuration;

[0015]- Figure 3' shows a sectional view of the valve group, according to the present invention, configured in a low temperature configuration referred to in Figure 3; [0016]- Figure 4 shows a sectional view of a diesel fuel filtration module comprising a valve group in accordance with the present invention configured in a high temperature configuration;

[0017]- Figure 4' shows a sectional view of the valve group, according to the present invention, configured in a high temperature configuration as referred to in Figure 4;

[0018]- Figure 5 shows a view with separate parts of the valve group referred to in Figures 3' and 4'; [0019]- Figure 6 shows a sectional view along the section plane XII-XII referred to in Figure 3'.

Detailed description

[0020]In the attached figures, reference numeral 1 indicates a valve group object of the present invention.

[0021]Furthermore, in the attached figures, reference numeral 900 indicates a diesel fuel filtration module of a vehicle which in turn is the object of the present invention.

[0022]In particular, the diesel fuel filtration module 900 comprising a filter group 999 housed in a filtration chamber 910.

[0023]Specifically, such filter group 999 performs diesel fuel filtration operations.

[0024]According to a preferred embodiment, such filter group 999 performs operations for separating the water from the diesel fuel. Preferably, the filter group 999 comprises a hydrophobic separator for separating water from diesel fuel in filtration.

[0025]Preferably, the diesel fuel filtration module 900 comprises a water level sensor housed in the bottom of the filtration chamber 910 and suitable for detecting the water level. Preferably, said water level sensor is operatively connected to an electric drainage valve suitable for allowing the drainage of the water accumulated in the filtration chamber 910.

[0026]According to the present invention, the diesel fuel filtration module 900 comprises a duct 950 which is fluidically connected to said filtration chamber 910, and the valve group 1 of the present invention has the purpose described above, as well as widely described below, finding accommodation and working in said duct 950.

[0027]In particular, said duct 950 extends along a duct axis C-C.

[0028]Furthermore, said duct 950 extends between a filter duct end 951 fluidically connected to said filtration chamber 910 and a tank duct end 952 fluidically connected to a vehicle tank.

[0029]Preferably, the filter duct end 951 is fluidically connected to the dirty side of the filter group 999.

[0030]Preferably, the filter duct end 951 is substantially housed in the filtration chamber 910.

[0031]Preferably, the filter duct end 951 is positioned inside the filtration chamber 910.

[0032]Preferably, the filter duct end 951 is open. In other words, at the filter duct end 951 there is a passage door.

[0033]According to a preferred embodiment, the tank duct end 952 is open, to allow the fluidic connection of the diesel fuel filtration module 900 to a vehicle tank.

[0034]Furthermore, the diesel fuel filtration module 900 comprises a return duct 980. Preferably, the return duct 980 is fluidically connectable, or is comprised in a return line comprised in the diesel fuel power supply circuit of the vehicle. Preferably, said return line is suitable for recirculating the excess diesel fuel coming from the injectors and/or from the high pressure pump towards the vehicle tank. The valve group 1 of the present invention is suitable for controlling the amount of diesel fuel to be recirculated towards the filtration chamber 910, in particular to heat the diesel fuel in situations wherein it is at low temperature, avoiding the filter group 999 clogging.

[0035]Preferably, the return duct 980 connects the return line of the diesel fuel power supply circuit of the vehicle to the diesel fuel filtration module 900, preferably to the duct 950.

[0036]According to a preferred embodiment, the duct 950 is fluidically connected to said return duct 980, between the filter duct end 951 and the tank duct end 952.

[0037]Preferably, the return duct 980 extends transversely, preferably orthogonally, to the duct 950.

[0038]Furthermore, the duct 950 comprises a filter opening 959 fluidically connected to the filtration chamber 910. [0039]Preferably, the filter opening 959 is positioned close to the filter duct end 951.

[0040]Preferably, the filter opening 959 is positioned along the duct axis C-C at an axial height different with respect to the region in which the duct 950 intercepts the return duct 980.

[0041]According to a preferred embodiment, the filter opening 959 is housed in the filtration chamber 910.

[0042]According to a preferred embodiment, the filter opening 959 is positioned on a radial wall of the duct 950. Preferably, the filter opening 959 is radially spaced apart from the duct axis C-C.

[0043]According to a preferred embodiment, the diesel fuel filtration module 900 comprises a filling duct 960 fluidically connected to the filtration chamber 910. Through said filling duct 960, operations to fill the filtration chamber 910 with diesel fuel in the first filling steps or, in any case, whenever it has been emptied are performed.

[0044]According to a preferred embodiment, the diesel fuel filtration module 900 also comprises a filling pump 969 fluidically connected to the filling duct 960.

[0045]Preferably, the filling pump 969 and the filling duct 960 are fluidically positioned downstream of the filter group 999. Preferably, the filling duct 960 communicates, on one side, with the inner cavity of the filter group 999 and, on the other, with the filling pump 969 which in turn is directly or indirectly connected to the outlet port of the diesel fuel filtration module.

[0046]Preferably, at said filling duct 960 a bypass valve is provided, suitable for bypassing the filling pump 969 when it is not active.

[0047]Preferably, with the filling duct 960 and the filling pump 969 arranged downstream of the filter group 999, said bypass valve puts the clean side of the filter group 999 in communication with the outlet port of the diesel fuel filtration module 900, thus avoiding the passage of diesel fuel through the filling pump 969 when it is not operating.

[0048]According to a preferred embodiment, the filling pump 969 imposes a suction step (or several suction steps) inside the filtration chamber 910, wherein a discrete volume of diesel fuel, sucked from the tank, reaches the filtration chamber 910 allowing the air contained in the filtration chamber 910 to escape in the delivery step. Preferably, each suction step corresponds to a delivery step, until the filtration module 900 is completely filled.

[0049]Preferably, said filling pump 969 is of the manually operable type. [0050]Preferably, said filling pump 969 is of the manual diaphragm type.

[0051]Preferably, said filling pump 969 is of the manual piston type.

[0052]Preferably, with the filling pump 969 of the manual type, the suction steps and the delivery steps are performed alternately, according to the movement imposed by the user on the diaphragm or on the piston of the pump.

[0053]Preferably, said filling pump 969 is of the electric type.

[0054]Preferably, in the case of a pump of the electric type, the suction step and the delivery step are performed substantially at the same time.

[0055]According to a preferred embodiment, the activation of the filling pump 969, in particular each suction step performed by the filling pump 969, imposes a depression suitable for drawing a discrete volume of diesel fuel from the tank into the filtration chamber 910 which is then progressively filled with diesel fuel. As described above, each delivery step performed by the filling pump 969 forces the evacuation of the air contained in the filtration chamber 910, allowing it to be filled with diesel fuel.

[0056]Preferably, each suction step imposed by the filling pump 969 involves the suction of diesel fuel in the filtration chamber 910 through a main inlet port 9100. Said main inlet port is connected to the vehicle tank and communicates with the dirty side of the filter group 999. [0057]As it is widely described below, the valve group 1 is suitable for interrupting the fluidic communication between the return duct 980 and the filtration chamber 910 during the activation of the pump.

[0058]According to a preferred embodiment, the diesel fuel filtration module 900 comprises a second filter group 999' housed in a second filtration chamber 910'. Preferably, said second filter group 999' is fluidically arranged downstream of the filter group 999 described above.

[0059]In accordance with a preferred embodiment, the second filter group 999' is suitable for performing a particle filtration of the diesel fuel in filtration.

[0060]Preferably, the second filter group 999' comprises means suitable for separating the water from the diesel fuel in filtration

[0061]Preferably, the filter group 999 acts as a pre- filter being fluidically arranged upstream of the second filter group 999'.

[0062]Preferably, the filter group 999 comprises means suitable for separating the water from the diesel fuel being filtered.

[0063]According to a preferred embodiment, the diesel fuel filtration module 900 comprises a main module body and a specific cover engageable to the main module body suitable for defining the filtration chamber 910 in which to insert the filter group 999.

[0064]According to a preferred embodiment, the diesel fuel filtration module 900 comprises a main module body and an appropriate second cover engageable to the main module body suitable for defining the second filtration chamber 910' in which to insert the second filter group 999'.

[0065]Preferably, said main module body comprises the connection ducts and/or it comprises the connection fittings for specific ducts, suitable for connecting the filter group 999 to the second filter group 999' as well as suitable for connecting said components to one or more external devices, such as, for example, to one or more external pump groups.

[0066]According to the present invention, the valve group 1 is housable in said duct 950.

[0067]According to the present invention, the valve group 1 extends along a valve axis V-V.

[0068]According to the present invention, the valve group

1 is housable in the duct 950 so that the valve axis V-V coincides with the duct axis C-C. [0069]In particular, according to a preferred embodiment, the valve group 1 is insertable as a cartridge into the duct 950 through an opening present in the tank duct end 952. In other words, according to a preferred embodiment, the valve group 1 is insertable into the duct 950 with a single operation. Preferably, all the components comprised in the valve group 1 and described below are insertable into the duct with a single insertion operation.

[0070]According the present invention, the valve group 1 comprises a valve body 2.

[0071]Preferably, the valve body 2 has a structural and supporting function.

[0072]Preferably, the valve body 2 has a substantially tubular shape defining a valve chamber 200.

[0073]Said valve body 2 extends in length along the valve axis V-V between one filter body end 21 and one tank body end 22.

[0074]Preferably, the filter body end 21 is positionable at the filter duct end 951. Preferably, the tank body end 22 is positionable at the tank duct end 952.

[0075]According to a preferred embodiment, the valve body 2 sealingly engages, in one region or in several regions, preferably in two regions, the side walls which define the duct 950. Preferably, the valve body 2 comprises at least one filter sealing region 27'. Preferably, the valve body 2 comprises at least one tank sealing region 27". Preferably, said sealing regions are made by means of a gasket element comprised in the valve body 2, or by means of one or more sealing lips integrally formed with the valve body 2.

[0076]According to a preferred embodiment, the valve body 2 is in a single piece.

[0077]According to a preferred embodiment, the valve body 2 consists of a plurality of portions 20', 20", 20"'.

[0078]Preferably, said portions 20', 20", 20"' are mutually engaged with one another, for example through a snap engagement.

[0079]Preferably, said portions 20', 20", 20"' are mutually engaged with one another through further components of the valve group 1.

[0080]According to a preferred embodiment, the components described below are housable in the valve body 2 in function of the position and/or the mutual interactions and/or the mutual spaces defined by the plurality of portions 20', 20", 20"'.

[0081]For example, in a preferred embodiment, one portion is suitable for accommodating the first device 4 described below, while the other portion is suitable for accommodating the second device 5 described below. [0082]According to the present invention, the valve body 2 comprises a diesel fuel inlet opening 28 between the filter body end 21 and the tank body end 22. Preferably, said diesel fuel opening 28 is in fluid communication with the return duct 980. Preferably, said diesel fuel inlet opening 28 is positioned at the return duct 980, i.e., in front of it.

[0083]According to the present invention, the valve body 2 comprises a filter outlet opening 29 suitable for being placed in fluidic communication with the filter opening 959.

[0084]Preferably, the valve body 2 comprises a filter outlet opening 29 arranged coaxially to the valve axis V- V.

[0085]Preferably, the valve body 2 comprises a filter outlet opening 29 placed in front of the filter opening 959.

[0086]Preferably, said filter opening 959 is proximal to the filter body end 21.

[0087]According to the present invention, the valve group 1 comprises an adjustment assembly 3.

[0088]Preferably, said adjustment assembly 3 is supported by the valve body 2.

[0089]Preferably, said adjustment assembly 3 is supported by the valve body 2, being almost entirely accommodated therein.

[0090]Said adjustment assembly 3 comprises a temperature- sensitive device 6 suitable for detecting the temperature of the diesel fuel, preferably in the filtration chamber 910.

[0091]The temperature-sensitive device 6 is positioned at the filter body end 21.

[0092]Preferably, the temperature-sensitive device 6 is positioned supported in a cantilever manner on the valve body 2, at the filter body end 21

[0093]Preferably, the temperature-sensitive device 6 is positioned so as to be housed inside the filtration chamber 910.

[0094]According to a preferred embodiment, the adjustment assembly 3 comprises a pair of adjustment devices 4, 5 housed on the valve body 2, and engaged with the temperature-sensitive device 6. In other words, the adjustment assembly 3 comprises a first device 4 and a second device 5 housed on the valve body 2, and engaged with the temperature-sensitive device 6.

[0095]Preferably, the adjustment devices 4, 5 are housed in the valve chamber 200.

[0096]The first device 4 engages the valve body 2 between the diesel fuel inlet opening 28 and the filter body end 21. [0097]Preferably, the first device 4 engages the valve body 2 between the diesel fuel inlet opening 28 and the filter opening 959.

[0098]Preferably, the first device 4 engages the valve body 2 at the filter outlet opening 29.

[0099]Preferably, the filter outlet opening 29 and the filter opening 959 are coaxial.

[00100] The second device 5 engages the valve body 2 between the diesel fuel inlet opening 28 and the tank body end 22.

[00101] According to a preferred embodiment, the first device 4 is axially movable along the axis V-V.

[00102] According to a preferred embodiment, the second device 5 is axially movable along the axis V-V.

[00103] According to a preferred embodiment, the first device 4 and the second device 5 are movable along the axis V-V in a mutually opposite direction towards the respective closing positions.

[00104] According to a preferred embodiment, the first device 4 and the second device 5 engage the valve body 2 in respective specially shaped seats. Preferably, said seats are axially spaced apart along the axis V-V and are arranged on the opposite sides of the diesel fuel inlet opening 28.

[00105] Furthermore, according to the present invention, the temperature-sensitive device 6 comprises an elongated stem 61 which extends along the valve axis V-V and engages both the first device 4 and the second device 5 to perform thereon distinct loading forces, widely described below.

[00106] According to a preferred embodiment, the temperature-sensitive device 6 comprises a wax member 60 with an actuator pin 600 with a variable position as function of the temperature. Preferably, said actuator pin 600 is engaged with the stem 61, so that a position of the stem 61 corresponds to a position of the actuator pin 600.

[00107] According to a preferred embodiment, the first device 4 comprises a first shutter 40 and a first elastic element 45 engaged with said first shutter 40. The temperature-sensitive device 6, as function of the detected temperature, performs a loading force on the first elastic element 45.

[00108] According to a preferred embodiment, the first elastic element 45 engages the first shutter 40 and the temperature-sensitive device 6. Preferably, the first elastic element 45 engages the first shutter 40 and the stem 61.

[00109] Preferably, the first elastic element 45 is a helical spring element which extends with respect to the valve axis V-V. Preferably, the helical spring element extends about the stem 61.

[00110] Preferably, the first shutter 40 engages the valve body 2 between the diesel fuel inlet opening 28 and the filter opening 959.

[00111] Preferably, the first shutter 40 engages the valve body 2 at the filter outlet opening 29.

[00112] Preferably, the filter outlet opening 29 and the filter opening 959 are coaxial.

[00113] According to a preferred embodiment, the temperature-sensitive device 6 as function of the detected temperature, performs a loading force on the first elastic element 45 which increases as the temperature increases.

[00114] According to a preferred embodiment, the temperature-sensitive device 6, as function of the detected temperature, performs a compression force F4', F4" on the first elastic element 45. Preferably, the intensity of said compression force increases with the increasing temperature.

[00115] According to a preferred embodiment, the second device 5 comprises a second shutter 50 and a second elastic element 55 engaged with said second shutter 50. Preferably, the temperature-sensitive device 6 as function of the detected temperature, performs a loading force on the second elastic element 55.

[00116] According to a preferred embodiment, the second elastic element 55 engages the second shutter 50 and the valve body 2.

[00117] Preferably, the second elastic element 55 is a helical spring element which extends with respect to the valve axis V-V.

[00118] Preferably, the second shutter 50 engages the valve body 2 between the diesel fuel inlet opening 28 and the tank body end 22.

[00119] According to a preferred embodiment, the temperature-sensitive device 6 as function of the detected temperature, performs a loading force on the second elastic element 55 which increases with the increasing temperature.

[00120] According to a preferred embodiment, the temperature-sensitive device 6, as function of the detected temperature, performs a compression force F5', F5" on the second elastic element 55. Preferably, the intensity of said compression force increases with the increasing temperature.

[00121] Preferably, the stem 61 extends through the first shutter 40 engaging the second shutter 50.

[00122] According to a preferred embodiment, the stem 61 identifies engagement steps, which are engageable by the first device 4, for example by the first shutter 40 or by the first elastic element 45, and by the second device 5, for example by the second shutter 50 or by the second elastic element 55.

[00123] According to the present invention, the valve group 1 is configurable in a low temperature configuration and in a high temperature configuration.

[00124] The low temperature configuration corresponds to a detection by the temperature-sensitive device 6 of a diesel fuel temperature Tfuel lower than a first threshold value Tl.

[00125] Preferably, the first threshold value Tl is also identifiable as a lower threshold value.

[00126] Preferably said first threshold value Tl is a temperature value below 15°C, preferably corresponding to about 10°C.

[00127] In the low temperature configuration, the temperature-sensitive device 6 controls a first loading force F4' on the first device 4.

[00128] With particular reference to Figure 3, it is emphasized how in said Figure a situation is shown in which the force exerted by the diesel fuel flow has exceeded the action of the first loading force F4' caused by the temperature-sensitive device 6 and the first device 4, in particular, the first shutter 40 is shown in a raised axial position.

[00129] The high temperature configuration corresponds to a detection by the temperature-sensitive device 6 of a diesel fuel temperature Tfuel higher than a second threshold value T2.

[00130] Preferably, the second threshold value T2 is also identifiable as an upper threshold value.

[00131] Preferably said second threshold value T2 is higher than 15°C, preferably it corresponds to about 20°C.

[00132] In the high temperature configuration, the temperature-sensitive device 6 controls a second loading force F4" on the first device 4.

[00133] According to the present invention, said second loading force F4" has an intensity which is greater than the first loading force F4'.

[00134] According to a preferred embodiment, in the low temperature configuration, the temperature-sensitive device 6 controls a first loading force F5' on the second device 5.

[00135] Furthermore, according to a preferred embodiment, in the high temperature configuration the temperature-sensitive device 6 controls a second loading force F5" on the second device 5. [00136] According to a preferred embodiment, said second loading force F5" has an intensity which is greater than the first loading force F5'.

[00137] According to a preferred embodiment, the first loading force F5' on the second device 5 has an intensity which is greater than the first loading force F4' on the first device 4.

[00138] Preferably, the second loading force F5" on the second device 5 has an intensity which is greater than the second loading force F4" on the first device 4.

[00139] In other words, in the low temperature configuration, the temperature-sensitive device 6 arranges the stem 61 in a position in which it engages the first device 4 and the second device 5 so that the flowing diesel fuel finds less resistance from the first device 4 with respect to the resistance opposed by the second device 5. In the low temperature configuration, therefore, the diesel fuel flows mostly, or entirely, towards the filtration chamber 910 rather than towards the vehicle tank.

[00140] Preferably, in the low temperature configuration, the intensity of the first loading force F5' on the second device 5 is such as not to prevent the flow of diesel fuel towards the tank in the event of overpressures in the return line. Advantageously, the components of the diesel fuel power supply circuit of the vehicle are protected from any possible pressure peaks in the low temperature configuration.

[00141] In other words, in the high temperature configuration, the temperature-sensitive device 6 arranges the stem 61 in a position in which it engages the first device 4 and the second device 5 so that the flowing diesel fuel finds less resistance from the second device 5 with respect to the resistance opposed by the first device 4. In the high temperature configuration, the diesel fuel flows mostly, or entirely, towards the vehicle tank rather than towards the filtration chamber 910.

[00142] Preferably, in the high temperature configuration, the intensity of the second loading force F4" on the first device 4 is such as not to prevent the flow of diesel fuel towards the filter opening in the event of overpressures in the return line. Advantageously, the components of the diesel fuel power supply circuit comprised in the vehicle are protected from any possible pressure peaks even at high temperatures .

[00143] According to a preferred embodiment, the loading force is the elastic loading force applied on the first elastic element 45 and/or on the second elastic element 55. [00144] According to a preferred embodiment of the present invention, the first device 4 and/or the second device 5 are configured to interrupt the communication of the return duct 980, and, in general, of the return line of the diesel fuel power supply circuit, with the filtration chamber 910 with the filling pump 969 operatively active.

[00145] According to a preferred embodiment of the present invention, the first device 4 and/or the second device 5 are configured to interrupt the communication of the return duct 980, and, in general, of the return line of the diesel fuel power supply circuit, with the filtration chamber 910 with the filling pump 969 operatively active and as function of the detected temperature.

[00146] In particular, in the low temperature configuration, the intensity of the first loading force F5' acting on the second device 5 is such as to resist the drawing force generated by the suction step imposed by the pump, interrupting the fluidic communication between the filtration chamber 910 and the return duct 980, in particular of the portion of the return duct communicating with the tank.

[00147] According to a preferred embodiment, the first device 4 interrupts the fluid communication between the return duct 980 and the filtration chamber 910, while the second device 5 interrupts the fluidic communication between the vehicle tank and the filtration chamber 910 acting as an additional safety element.

[00148] According to a preferred embodiment, the second shutter 50 has at least one calibrated hole 500, preferably a plurality of calibrated holes.

[00149] According to a preferred embodiment, the second shutter 50 comprises a membrane element 58 suitable for reaching the flow of diesel fuel through the calibrated hole 500 in the presence of a negative pressure in the filtration chamber 910. Preferably, said membrane element 58 is an umbrella valve.

[00150] In particular, in the high temperature configuration, the intensity of the second loading force F4" on the first device 4 is such as to resist the drawing force generated by the suction step imposed by the filling pump 969, interrupting the fluidic communication between the filtration chamber 910 and the return duct 980.

[00151] Innovatively, the valve group and the diesel fuel filtration module which comprises it fully fulfill the purpose of the present invention, overcoming the typical problems of the prior art.

[00152] Advantageously, the valve group is suitable being housed in a special duct of the diesel fuel filtration module and to adjust the inflow of diesel fuel into the filtration chamber during the operating steps.

[00153] Advantageously, the valve group is suitable for being housed in a special duct of the diesel fuel filtration module and to adjust the inflow of diesel fuel into the filtration chamber during the steps of filling the filtration module.

[00154] Advantageously, the valve group is configured so as to perform a variable loading force on the first device, allowing to adequately manage the flow of diesel fuel towards the filtration chamber both as function of the temperature and as function of the pressure of the diesel fuel itself.

[00155] Advantageously, the valve group is configured so as to perform a loading force that increases as the increasing temperature on the first elastic element and on the second elastic element. Advantageously, the circulation of the preferential diesel fuel is favored towards the low temperature filtration chamber and towards the high temperature tank, while maintaining safety functions useful for releasing any possible overpressure in the circuit active.

[00156] Advantageously, the valve group is suitable for partializing the flow of diesel fuel coming from the return line, thus allowing to manage any possible overpressures present in the circuit both in the high temperature configuration and in the low temperature configuration .

[00157] Advantageously, the valve group is suitable for managing the flow of diesel fuel even in the presence of very high flow rates, in particular it is capable of managing the entire flow rate of the diesel fuel flow returning from the high pressure pump of the circuit. Advantageously, the valve group allows to simplify the circuit structure, reducing any possible solutions to intercept reduced flow rates from the return line towards the filtration module.

[00158] Advantageously, the valve group autonomously operates, requiring no further control components.

[00159] Advantageously, the valve group accurately detects the temperature in the filtration chamber to act accordingly in a precise manner.

[00160] Advantageously, the valve group adequately manages the flow of diesel fuel in filtration even in the presence of negative pressure in the filtration chamber.

[00161] Advantageously, the calibrated hole/calibrated holes allows/allow the flow of diesel fuel towards the tank in a low temperature configuration and with an inactive filling pump, preventing the occurrence of overpressures in the return line even in cold starting conditions of the vehicle.

[00162] Advantageously, the calibrated hole/calibrated holes causes/cause a pressure drop between the filtration chamber and the return line which is sufficient to isolate the portion of the return duct arranged downstream of said hole/holes from the filtration chamber in conditions of low temperature and with the pump active, thus reducing the number of components required and the cost of the valve assembly.

[00163] Advantageously, the calibrated hole/calibrated holes in combination with the first device comprised in the valve group allows/allow to introduce a pressure drop which is sufficient to inhibit the drawing of diesel fuel from the return line in the case of negative pressure in the filtration chamber and in low temperature conditions. [00164] Advantageously, the valve group is easy to maintain and inspect.

[00165] Advantageously, the valve group comprises a pair of devices operatively engaged by the same temperature-sensitive adjustment element, thus allowing to adequately manage the flow of diesel fuel with the filling pump active both in the low temperature configuration and in the high temperature configuration and at intermediate temperatures during any possible operational transients.

[00166] Advantageously, the diesel fuel filtration module allows to suitably manage the steps of filling the module performed by means of the filling pump comprised therein, thus allowing the inflow of diesel fuel into the filtration chamber, the removal of the air initially present in said chamber and avoiding the entry of air and fuel from the return line used to heat the diesel fuel in the filtration chamber.

[00167] Advantageously, the filling pump and the filling channel are fluidically arranged downstream of the filter group so as to avoid the clogging thereof by contaminants present in the diesel fuel in filtration.

[00168] It is clear that, in order to meet contingent needs, those skilled in the art may make changes to the invention, all contained within the scope of protection as defined by the following claims.

List of reference signs:

[00169]

1 valve group

2 valve body

21 filter body end

22 tank body end

20', 20", 20"' body portions

27' filter sealing region 27" tank sealing region 28 diesel fuel inlet opening 29 filter outlet opening 200 valve chamber

3 adjustment assembly

4 first device

40 first shutter

45 first elastic element

5 second device

50 second shutter

55 second elastic element

500 calibrated hole

58 membrane element

6 temperature-sensitive element

60 wax member

600 actuator pin

61 stem

900 diesel fuel filtration module

910 filtration chamber

9100 main inlet port

950 duct

951 filter duct end

952 tank duct end

959 filter opening

960 filling duct 969 filling pump

980 return duct

999 filter group

910' second filtration chamber 999' second filter group

C-C duct axis

V-V valve axis

Tfuel diesel fuel temperature value

T1 first threshold value T2 second threshold value

F4' first loading force on the first device

F4" second loading force on the first device

F5' first loading force on the second device

F5" second loading force on the second device