Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present disclosure relates to a fuel pressure regulator.

Background of the invention:
[0002] According to a prior art US7624720 discloses a variable set point fuel pressure regulator. A fuel pressure regulator is provided. The fuel pressure regulator includes a body forming an inlet and an outlet, a seal element positioned intermediate the inlet and the outlet, an armature positioned to apply force to the seal element, and a solenoid coiled around the armature, wherein excitation of the solenoid causes a change in at least one of a position of the armature relative to the seal element and a force applied by the armature to the seal element to vary a regulated fuel pressure set-point at which fuel flows through the outlet.

Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0004] Fig. 1 illustrates a side cross-section view of a fuel pressure regulator in a default position, according to an embodiment of the present invention;
[0005] Fig. 2 illustrates a side cross-section view of the fuel pressure regulator after actuation, according to an embodiment of the present invention;
[0006] Fig. 3 illustrates a perspective cross-section view of the fuel pressure regulator, according to an embodiment of the present invention;
[0007] Fig. 4 illustrates a cut-out view of the fuel pressure regulator, according to an embodiment of the present invention, and
[0008] Fig. 5 illustrates a Fuel Supply Module secured to the fuel pressure regulator, according to an embodiment of the present invention.

Detailed description of the embodiments:
[0009] Fig. 1 illustrates a side cross-section view of a fuel pressure regulator in a default state, according to an embodiment of the present invention. The fuel pressure regulator 100 comprises a body 104 having an inlet 116 and an outlet 126, with free flow of fuel between the inlet 116 and the outlet 126. An opening 118, 124 in each of the inlet 116 and the outlet 126 fluidly connects to an accumulation chamber 134. A seal member 120 is positioned between the inlet 116 and the outlet 126, the seal member 120 comprises a return passage 122. A valve element 136 is positioned over a seat 132 of the return passage 122, and urged in closing direction by a spring 138. The valve element 136 provided at an end of a piston 102 which is actuatable by a solenoid 140, characterized in that, a cover member 130 extending from the end of the piston 102, and designed to circumscribe the valve element 136. The cover member 130 is hydraulically coupled with the seal member 120 and is operable in reciprocating manner to control flow of fuel from the accumulation chamber 134 to the return passage 122, and thus regulate fuel pressure at the outlet 126.

[0010] According to an embodiment of the present invention, the fuel pressure regulator 100 comprises a first chamber (not referenced) at the top which is occupied by the solenoid 140. A second chamber (not referenced) is below the first chamber which houses the spring 138. A third chamber or the accumulation chamber 134 is positioned below the second chamber. The third chamber and the second chamber are separated by a diaphragm 106. The piston 102 passes through the first chamber and the second chamber and ends in the third chamber. The valve element 136 is provided at a head of the piston 102. The head of the piston 102 is also secured to the diaphragm 106 and comprises a shoulder on which the spring 138 exerts pressure towards the third chamber.

[0011] In accordance to an embodiment of the present invention, a shim stack 114 is secured to the cover member 130 and adapted to close the openings 118, 124 in each of the inlet 116 and the outlet 126 respectively. The shim stack 114 is displaced by the fuel when the fuel pressure increases beyond a threshold pressure. The fuel flows from the inlet 116 into the return passage 122 back to a fuel tank 502 (shown in Fig. 5) via the accumulation chamber 134. The threshold pressure is pre-determined based on user application. The fuel flows into the return passage 122 and back to a fuel tank 502 (shown in Fig. 5).

[0012] In accordance to an embodiment of the present invention, the cover member 130 comprises a first set of bores 112 and a second set of bores 108. The seal member 120 comprises a third set of bores 128. The first set of bores 112 and the third set of bores 128 are in fluid communication under default conditions as shown.

[0013] Fig. 2 illustrates a side cross-section view of the fuel pressure regulator after actuation, according to an embodiment of the present invention. The first set of bores 112 is closed due to upward displacement of the seal member 120, which causes a closure of the third set of bores 128, but opens upon downward displacement of the piston 102 due to de-activation of the solenoid 140. A first path is formed for return of fuel stored in the accumulation chamber 134 through the first set of bores 112 and the third set of bores 128. In other words, the second set of bores 108 is closed by surface of the seal member 120 and the valve element 136 in default conditions, and opens to the return passage 122 upon actuation of the solenoid 140 by a controller (shown in Fig. 5).

[0014] In accordance to the present invention, the valve element 136 comprises curved surface 202 such as hemi-spherical surface or a convex surface and secured with a flexible material 110 such as an elastomer. The valve element 136 is lifted from the seat 132 on energization/actuation/excitation of the solenoid 140. The lifting of the valve element 136 also opens a second path between the accumulation chamber 134 and the return passage 122 through the second set of bores 108, whereas the third set of bores 128 is blocked due to the upward displacement of the piston 102.

[0015] According to the present invention, a working of the fuel pressure regulator 100 is explained using Fig. 1 and Fig. 2 as an example. Consider the inlet 116 receives fuel from an outlet of a feed/fuel pump (not referenced). The inlet 116 is directly and freely coupled to the outlet 126. So, any excess fuel in the fuel path causes the shim stack 114 to be displaced due to pressurized fuel flowing through the inlet 116. The excess fuel gets stored in the accumulation chamber 134, and after reaching to a certain level/height, flows through the first set of bores 112 and the third set of bores 128 into the return passage 122. The fuel then flows back to the fuel tank 502. However, during high load conditions or other conditions, the controller electronically controls the solenoid 140 of the fuel pressure regulator 100, to utilize the second path.

[0016] In Fig. 2, when the solenoid 140 is activated, the shim stack 114 lifts thereby allowing free flow of pressurized fuel from the inlet 116 into the accumulation chamber 134. The cover member 130 is displaced upwardly and blocks the path through the third set of bores 128. However, when the valve element 136 is lifted/displaced upwardly, the second set of bores 108 gets opened, which was earlier covered by the curved surface 202 of the valve element 136. The fuel flows through the second set of bores 108 into the return passage 122 and back to the fuel tank 502. Thus, the excess fuel is sent back to the fuel tank 502 and only the required fuel pressure is maintained in the fuel delivery line (not shown) to a high pressure fuel pump or a common rail downstream of the outlet 126.

[0017] Fig. 3 illustrates a perspective cross-section view of the fuel pressure regulator, according to an embodiment of the present invention. The diaphragm 106 is slanted but not limited thereto. Further, the spring 138 is shown wound around the piston 102 and is in an expanded state by default. The cover member 130 is shown as cylindrical shape with first set of bores 112 and the second set of bores 108. The shim stack 114 is in circular shape and positioned on the cover member 130. The shim stack 130 closes the opening 118, 124 of the inlet 116 and the outlet 126, respectively.

[0018] According to an embodiment of the present invention, the fuel pressure regulator 100 is positioned upstream of a fine fuel filter 516 (shown in Fig. 5) and downstream of a fuel pump 512 (shown in Fig. 5). Therefore the return flow of fuel is returned back to the fuel tank 502 without unnecessarily/excess passing through the fuel filter 516 and getting filtered by the fuel filter 516. The fuel pressure regulator 100 is electronically controlled by the controller 522 based on operating conditions of an engine 520 (shown in Fig. 5). The present invention discloses to place the electronically controlled fuel pressure regulator (ePRG) 100 between the feed pump outlet path after the one way mechanical check valve and before the fine fuel filter 516. The fuel pressure regulator 100 comprises a return passage 122 (or a leak port) to leak the excess fuel that is more than the engine manifold requirement back to the fuel tank 502 at that point without being filtered by the fine fuel filter 516. The fuel pressure regulator 100 does not send excess fuel to the fine fuel filter 516 which extends the useful life of the fine fuel filter 516 and avoid excess back pressure to the fine fuel filter 516.

[0019] Fig. 4 illustrates a cut-out view of the fuel pressure regulator, according to an embodiment of the present invention. The solenoid 140 is actuated by the controller 522 and which lifts the piston 102 (which acts as the armature). The lifting of piston 102 causes lifting of the valve element 136 from the seat 132. The fuel pressure regulator 100 shown in Fig. 4 is in an activated state. The openings 118 and 124 in the inlet 116 and the outlet 126 are clearly seen as the shim stack 114 is also lifted which is fixed/secured to the cover member 130. The piston 102 is operated by actuation and de-actuation of the solenoid 140 by means of the controller 522 in response to engine operating parameters. The annular chamber 402 fluidly coupling the inlet 116 and the outlet 126. The annular chamber 402 is formed around the seal member 120.

[0020] According to the present invention, the controller 522 is provided with necessary signal detection, acquisition, and processing circuits. The controller 522 is the control unit which comprises input/output interfaces having pins or ports, a memory element (not shown) such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and a Digital-to-Analog Convertor (DAC), clocks, timers, counters and at least one processor (capable of implementing machine learning) connected with each other and to other components through communication bus channels. The memory element is pre-stored with logics or instructions or programs or applications or modules/models and/or threshold/safe limit values/ranges, predefined/predetermined criteria which is/are accessed by the at least one processor as per the defined routines. The internal components of the controller 522 are not explained for being state of the art, and the same must not be understood in a limiting manner. The controller 522 may also comprise communication units to communicate with external computer or server/cloud computer through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, and the like. The controller 522 is implementable in the form of System-in-Package (SiP) or System-on-Chip (SOC) or any other known types. Examples of controller 522 comprises but not limited to, microcontroller, microprocessor, microcomputer, etc.

[0021] Fig. 5 illustrates a Fuel Supply Module secured to the fuel pressure regulator, according to an embodiment of the present invention. The system 500 shows the Fuel Supply Module (FSM) 518 that is positioned inside a fuel tank 502. The FSM 518 comprises a fuel pump 512 with a pre-filter 510 and internally connected to a nozzle 508 and a jet pump 506 as known in the art. The outlet of the fuel pump 512 is provided with a mechanical non-return valve (NRV) 504. The outlet of the fuel pump 512 then connects to the fuel pressure regulator 100 and to the fine filter 516. The fuel is then delivered to a common rail using a high pressure pump or directly to injectors of the engine 520. There is also provided a fuel level sensor 514 which is either with float or float less.

[0022] In accordance to an embodiment of the present invention, the fuel pressure regulator 100 is positioned in the feedline after NRV 504 and before the fine fuel filter 516. The fuel pressure regulator 100 is controlled by the controller 522 for supplying fuel with suitable pressure requirement to the engine 520 through the fine fuel filter 516.

[0023] Example: At cold start condition, the controller 522 triggers the fuel pressure regulator 100 to regulate the fuel flow at a high mass flow rate so that the injector injects the fuel at high pressure at the high mass flow rate rich fuel mixture into the engine manifold and thereby cause faster fuel ignition. The same controller 522 is also capable to trigger the fuel pressure regulator 100 to maintain the fuel flow at a low mass flow rate so that the injector injects the fuel at low pressure to enable a low mass flow rate lean fuel mixture into the engine manifold and thereby cause slower fuel ignition and to get good emission performance out of the engine 520 at normal operating conditions of the engine 520.

[0024] The positioning of the fuel pressure regulator 100 provides advantageous situation for the fine fuel filter 516 to extend its useful life, due to the fuel pressure regulator 100 being adapted in the feed line only before the fine fuel filter 516. Therefore, the fuel pressure regulator 100 is controllable by the controller 522 to supply only the required quantity of fuel to the fine fuel filter 516 for filtration that is actually required to be injected into the inlet manifold of the engine 520. The excess pressurized fuel that is supplied by the fuel pump 512 and located between the fuel pump 512 and the fine fuel filter 516 is dynamically channeled (in real time) through the return passage 122 (backflow path) in the fuel pressure regulator 100 to the fuel tank 502. Therefore, excess pressurized fuel that is normally supplied to the fine fuel filter 516 is avoided completely, thereby extending a useful life of the fine fuel filter 516 substantially as only the quantity of fuel that is required to be injected into the inlet manifold of the engine 520 is actually filtered by the fine fuel filter 516. In addition, as only the quantity of fuel to the fuel filter 516 is supplied that is actually required to be injected into the inlet manifold of the engine 520, substantial back pressure acting on the fine fuel filter material is avoided. The fuel pressure regulator 100 is operated by the controller 522 continuously to deliver the fuel at dynamic operating fuel flow rates in line with engine manifold requirement and also to relief the difference amount of fuel back to the fuel tank 502 through the return passage 122.

[0025] According to the present invention, the FSM 518 with electronic fuel pressure regulator 100 positioned between the fuel pump 512 supply path and a fine fuel filter 516 and electronically controlled by the controller 522 is provided. The variable pressure in FSM 518 brings some benefits in fuel line like vehicle cold start, good emission controls. In gasoline or petrol based FSM 518, the present invention provides an electronically controlled fuel pressure regulator 100 controlled by the controller 522 with demand based variable pressure concept upstream of the fine fuel filter 516. This leads to good cold start application and extends the fine fuel filter 516 useful life by avoiding excess fuel filtration, and back pressure in the fine fuel filter 516 is realized.

[0026] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims. 
, Claims:We claim:
1. A fuel pressure regulator (100), comprising:
a body (104) having an inlet (116) and an outlet (126), with free flow of fuel between said inlet (116) and said outlet (126);
at least one opening (118, 124) in each of said inlet (116) and said outlet (126) connecting to an accumulation chamber (134);
a seal member (120) positioned between said inlet (116) and said outlet (126), said seal member (120) comprises a return passage (122), and
a valve element (136) positioned over a seat (132 )of said return passage (122), and urged in closing direction by a spring (138), said valve element (136) provided at an end of a piston (102) which is actuatable by a solenoid (140), characterized in that
a cover member (130) extending from said end of said piston (102), and designed to circumscribe said valve element (136), said cover member (130) is hydraulically coupled with said seal member (120) and is operable in reciprocating manner to control flow of fuel from said accumulation chamber (134) to said return passage (122).

2. The fuel pressure regulator (100) as claimed in claimed 1, wherein a shim stack (114) is secured to said cover member (130) and adapted to close said opening (118, 124) in each of said inlet (116) and said outlet (126), wherein said shim stack (114) is displaced by fuel when fuel pressure increases beyond a threshold pressure, wherein fuel flows from said inlet (116) into said return passage (122) back to a fuel tank (502) via the accumulation chamber (134).

3. The fuel pressure regulator (100) as claimed in claim 1, wherein said cover member (130) comprises a first set of bores (112) and a second set of bores (108), and said seal member (120) comprises a third set of bores (128), and wherein said first set of bores (112) and said third set of bores (128) are in fluid communication under default conditions.

4. The fuel pressure regulator (100) as claimed in claim 3, wherein said second set of bores (108) is closed by surface of said seal member (120) and said valve element (136), and opens to said return passage (122) upon actuation of said solenoid (140).

5. The fuel pressure regulator (100) as claimed in claim 1, wherein said valve element (136) comprises a curved surface (202) that is secured to a flexible material (110) such as an elastomer.

6. The fuel pressure regulator (100) as claimed in claimed 1, wherein said piston (102) is operated by actuation and de-actuation of said solenoid (140) by means of a controller (522) in response to engine operating parameters.

7. The fuel pressure regulator (100) as claimed in claim 1, wherein an annular chamber (402) fluidly connects said inlet (116) and said outlet (126), said annular chamber (402) is formed around said seal member (120).

8. The fuel pressure regulator (100) as claimed in claim 1 is positioned upstream of a fine fuel filter (516) and downstream of a fuel pump (512).