EP3097304A1 - High pressure fuel pump - Google Patents
High pressure fuel pumpInfo
- Publication number
- EP3097304A1 EP3097304A1 EP14805942.1A EP14805942A EP3097304A1 EP 3097304 A1 EP3097304 A1 EP 3097304A1 EP 14805942 A EP14805942 A EP 14805942A EP 3097304 A1 EP3097304 A1 EP 3097304A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- camshaft
- fuel pump
- chamber
- partition
- hollow part
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
- F02M55/04—Means for damping vibrations or pressure fluctuations in injection pump inlets or outlets
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/12—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps having other positive-displacement pumping elements, e.g. rotary
- F02M59/14—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps having other positive-displacement pumping elements, e.g. rotary of elastic-wall type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
- F02M59/445—Selection of particular materials
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
- F04B1/0404—Details or component parts
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
- F04B11/0008—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators
- F04B11/0033—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators with a mechanical spring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/03—Fuel-injection apparatus having means for reducing or avoiding stress, e.g. the stress caused by mechanical force, by fluid pressure or by temperature variations
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/26—Fuel-injection apparatus with elastically deformable elements other than coil springs
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/31—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/31—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements
- F02M2200/315—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements for damping fuel pressure fluctuations
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/90—Selection of particular materials
- F02M2200/9015—Elastomeric or plastic materials
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
- F02M63/0001—Fuel-injection apparatus with specially arranged lubricating system, e.g. by fuel oil
Definitions
- the present invention relates to a fuel pump integrating a damper to absorb hydraulic waves propagating in the fluid.
- a fuel circuit feeding a vehicle engine comprises a lift pump that flows fuel from a low pressure tank to a high pressure fuel pump that highly pressurizes the fuel prior to flow it to injectors.
- a high pressure pump known in the art comprises a rotating camshaft cooperating with a piston that reciprocally slides within a bore in order to pressurize the fuel in a compression chamber.
- the camshaft is guided in rotation between two bushings and, in operation a back flow of low pressure fuel wets the camshaft and flows through the bushings, lubricating the surfaces, and returning to the low pressure line. Hydraulic waves propagate in said back flow and generate noise, the pulsations impacting the other components of the low pressure line, such as a filter.
- a fuel pump comprising a fixed body in which is received, between rotational guiding means, such as coaxial bushings, a camshaft cooperating with a piston slidably guided within a bore.
- the camshaft is adapted to rotate and actuates the piston to reciprocally move within the bore in order to pressurize fuel within a compression chamber.
- the camshaft is provided with an integral fluid damper so that hydraulic waves propagating in a fluid wetting the camshaft and flowing through the rotational guiding means are damped.
- the camshaft is partially hollow and the fluid damper is arranged in the hollow part.
- the camshaft is further provided with a channel extending through the wall of the camshaft and establishing a fluid communication between the external surface of the camshaft and the internal hollow part.
- the damper in camshaft of the pump is a solution that provides advantages such as to be able to be done with minimum effort and low number of parts.
- the damper comprises a deformable partition member arranged in the hollow part.
- the partition deformations enable to absorb hydraulic waves by varying the volume of a first chamber (50) wherein opens the communication channel (46).
- the partition member is arranged inside the hollow part, separating the hollow part into the first chamber and a second chamber.
- the second chamber can be open in fluid communication with the fluid flow (FR) or in another embodiment it can be closed.
- the partition member can arranged at the extremity of the hollow part, the volume of the first chamber being equal to the volume of the hollow part.
- the partition In absence of hydraulic waves, the partition, remains in a rest position and, when hydraulic waves occur, the partition deforms or displaces away from said rest position.
- the partition is a deformable elastic membrane, for instance a metal sheet.
- the damper is cylindrical and the partition is a piston slidably guided in said cylindrical shape, a spring soliciting the piston toward a rest position.
- the camshaft is a composite shaft comprising a cylindrical axle shaft over which is fixedly press fitted a cam.
- Figure 1 is a sketch of a fuel circuit of a vehicle.
- Figure 2 is a cross section of a fuel pump according to a first embodiment of the invention.
- Figure 3 is a cross section of a fuel pump according to another embodiment of the invention.
- Figure 4 is an alternative to the first embodiment of figure 2.
- FIG. 1 is a non- limiting sketchy representation of a vehicle 8 having an engine 10 in which is arranged simplified fuel equipment 12. This is not limited to any specific type of vehicle, or of fuel, and the teachings of the invention are applicable to diesel as well as to gasoline or any other fuel.
- a fuel tank 14 and a low pressure pump 16 In the rear of the vehicle 8 are arranged a fuel tank 14 and a low pressure pump 16 and, in the front, on the vehicle engine 10, are arranged a high pressure pump 18, a manifold 20, also known as a common-rail, distributing high pressure fuel to a plurality of injectors 22.
- a manifold 20 also known as a common-rail, distributing high pressure fuel to a plurality of injectors 22.
- a low pressure supply line 24 extending from the tank 14 to the high pressure pump 18, a high pressure circuit 26 confined between the high pressure pump 18, the manifold 20 and the injectors 22 and, a return low pressure line 28 extending from the front to the rear of the vehicle 8 to flow some fuel back from the injectors 22 back to the tank 14.
- Both supply and return low pressure lines 24, 28, are long extending between the front and the rear of the vehicle 10 and, inside said lines, low pressure fuel flows and propagate hydraulic waves generated for instance by the operation of the high pressure pump , or by an injection event.
- the pump 18 comprises a fixed body 30 having a left member 32 spaced apart from a right member 34.
- each member 32, 34 is rotationally arranged a camshaft 36, extending along a first axis Al, that cooperates with a piston via a cam follower, not represented.
- each member 32, 34 is provided with a bushing 38 that are coaxially Al arranged.
- the camshaft 36 has one cam 40 arranged between the members 32, 34.
- the non-represented part of the pump 18 comprises the piston cooperating with the cam 40 to reciprocally slide along a second axis A2 within a bore wherein it pressurizes fuel in a compression chamber.
- part of the fuel creates a low pressure back flow F that wets the camshaft 36 then divides into a front back flow FF and a rear back flow FR, going through the bushings 38 lubricating the rotating surfaces. Hydraulic waves propagate in said back flows generating undesired pulsations in the low pressure return line.
- the camshaft 36 is provided with a fluid damper 42.
- the camshaft 36 is manufactured partially hollow, said hollow part 44 axially Al extending inside the camshaft 36 from approximately half the middle of the camshaft 36 to the right extremity of the camshaft 36 where it opens in the rear back flow FR.
- the blind end of the hollow cylinder 44 is between the bushings 38 and, the hollow cylinder 44 is in fluid communication with the interior of the pump 10 via a channel 46 extending from the hollow cylinder 44, in the vicinity of said blind end, to the outer surface of the camshaft 36.
- a transversal elastic membrane 48 for instance a thin sheet of metal laser welded on the shaft, which divides the hollow cylinder 44 into a first chamber 50, where are the blind end and the channel 46, and a second chamber 52 represented on the right of the membrane 48.
- the membrane 48 is normally plane in a rest position and, should it deform, its elastic properties solicit it permanently to return to said plane rest position.
- the inside of the first chamber 50 is filled with fuel.
- the hydraulic waves propagate along the back flow F enter the channel 46, get in the first chamber 50 and deform the membrane 48 varying the volume and damping the hydraulic pulsations of the flow.
- the total volume of the two chambers remains constant.
- the right extremity of the hollow cylinder 44 cylinder is open, filled with fuel and when the membrane deforms, fuel is expelled from the second chamber.
- the membrane can be arranged at the right extremity of the hollow part, as shown in figure 4, the first chamber taking all the volume of the hollow part.
- the right extremity of the hollow part may be closed, and the membrane be installed, as in figure 2, inside the hollow part.
- the second chamber 52 is then filled with air, or another gas.
- the membrane 48 deforms and slightly compresses the gas in the second chamber 52.
- the first chamber 50 is smaller than the second chamber 52, in other alternatives, the reverse can be made with the first chamber 50 being larger than the second chamber 52, said second chamber 52 being open or closed.
- FIG. 3 Another embodiment is sketched on figure 3.
- the membrane 48 has been replaced by a sliding piston 54 that is permanently solicited in a rest position by a spring 56 arranged in the second chamber 52.
- the hydraulic waves displace the piston varying the volume of the chambers 50, 52.
- the camshaft 36 can be mono-bloc, made of one piece, or can be composite, made of a cylindrical axle shaft over which is fixedly arranged, for instance by, a cam.
- An advantage of the latter construction is to utilize for the axle shaft a lower grade steel than what is used for the cam. In this case manufacturing the hollow cylinder may be easier.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
A fuel pump (18) comprises a fixed body (30) and a camshaft (36) cooperating with a piston slidably guided within a bore. The camshaft (36) is adapted to rotate and reciprocally actuate the piston inside the bore in order to pressurize fuel within a compression chamber. The camshaft (36) is provided with an integral fluid damper (42) adapted to damp hydraulic waves propagating in the fluid flowing through the rotational guiding (38).
Description
High Pressure fuel pump TECHNICAL FIELD
The present invention relates to a fuel pump integrating a damper to absorb hydraulic waves propagating in the fluid.
BACKGROUND OF THE INVENTION
A fuel circuit feeding a vehicle engine comprises a lift pump that flows fuel from a low pressure tank to a high pressure fuel pump that highly pressurizes the fuel prior to flow it to injectors.
A high pressure pump known in the art comprises a rotating camshaft cooperating with a piston that reciprocally slides within a bore in order to pressurize the fuel in a compression chamber. The camshaft is guided in rotation between two bushings and, in operation a back flow of low pressure fuel wets the camshaft and flows through the bushings, lubricating the surfaces, and returning to the low pressure line. Hydraulic waves propagate in said back flow and generate noise, the pulsations impacting the other components of the low pressure line, such as a filter.
Existing standard solutions are, for instance, low pressure regulators that feed the pulsations back to the back flow but, these regulators are CO2 relevant. Another approach is to arrange inlet orifices in the return line but, as they restrict the flow section, the low pressure pump of the fuel circuit has to provide additional flow. SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to solve the above mentioned problems by providing a fuel pump comprising a fixed body in which is received, between rotational guiding means, such as coaxial bushings, a camshaft cooperating with a piston slidably guided within a bore. The camshaft is adapted to rotate and actuates the piston to reciprocally move within the bore in order to pressurize fuel within a compression chamber. The camshaft is provided with an integral fluid damper so that hydraulic waves propagating in a fluid wetting the camshaft and flowing through the rotational guiding means are damped.
The camshaft is partially hollow and the fluid damper is arranged in the hollow part. The camshaft is further provided with a channel extending through the wall of the camshaft and establishing a fluid communication between the external surface of the camshaft and the internal hollow part.
The damper in camshaft of the pump is a solution that provides advantages such as to be able to be done with minimum effort and low number of parts.
The damper comprises a deformable partition member arranged in the hollow part. The partition deformations enable to absorb hydraulic waves by varying the volume of a first chamber (50) wherein opens the communication channel (46).
In an embodiment the partition member is arranged inside the hollow part, separating the hollow part into the first chamber and a second chamber.
The second chamber can be open in fluid communication with the fluid flow (FR) or in another embodiment it can be closed.
Furthermore, the partition member can arranged at the extremity of the hollow part, the volume of the first chamber being equal to the volume of the hollow part.
In absence of hydraulic waves, the partition, remains in a rest position and, when hydraulic waves occur, the partition deforms or displaces away from said rest position. To enable such deformations, the partition is a deformable elastic membrane, for instance a metal sheet.
In another embodiment the damper is cylindrical and the partition is a piston slidably guided in said cylindrical shape, a spring soliciting the piston toward a rest position.
In any embodiment, the camshaft is a composite shaft comprising a cylindrical axle shaft over which is fixedly press fitted a cam.
In contrast to known low pressure regulator, there is no flow between inlet and return line, thus there is no impact on CO2. It is only a time wise deflection of a membrane or the displacement of the piston, giving some space for a pressure wave. BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is now described by way of example with reference to the accompanying drawings in which:
Figure 1 is a sketch of a fuel circuit of a vehicle.
Figure 2 is a cross section of a fuel pump according to a first embodiment of the invention.
Figure 3 is a cross section of a fuel pump according to another embodiment of the invention.
Figure 4 is an alternative to the first embodiment of figure 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description, similar elements will be designated with the same reference numbers. Also, to ease and clarify the description the orientation of the figures will be followed in reference without any limiting intention. Therefore, words and expressions such as "top, upper, lower, over, under, horizontal or vertical"... may be utilized.
Figure 1 is a non- limiting sketchy representation of a vehicle 8 having an engine 10 in which is arranged simplified fuel equipment 12. This is not limited to any specific type of vehicle, or of fuel, and the teachings of the invention are applicable to diesel as well as to gasoline or any other fuel. In the rear of the vehicle 8 are arranged a fuel tank 14 and a low pressure pump 16 and, in the front, on the vehicle engine 10, are arranged a high pressure pump 18, a manifold 20, also known as a common-rail, distributing high pressure fuel to a plurality of injectors 22. These components are arranged in fluid communication with each other via a low pressure supply line 24 extending from the tank 14 to the high pressure pump 18, a high pressure circuit 26 confined between the high pressure pump 18, the manifold 20 and the injectors 22 and, a return low pressure line 28 extending from the front to the rear of the vehicle 8 to flow some fuel back from the injectors 22 back to the tank 14.
Numerous variants of fuel equipment 12 exist with vehicles 8 having the engine in the front or in the rear and the fuel tank arranged at the other end. Both supply and return low pressure lines 24, 28, are long extending between the front and the rear of the vehicle 10 and, inside said lines, low pressure fuel flows and propagate hydraulic waves generated for instance by the operation of the high pressure pump , or by an injection event.
A first embodiment of the invention is now described in reference to figure 2 where the piloting part of the high pressure fuel pump 18 is sketched. The pump 18 comprises a fixed body 30 having a left member 32 spaced apart from a right member 34.
Between the members 32, 34, is rotationally arranged a camshaft 36, extending along a first axis Al, that cooperates with a piston via a cam follower, not represented. To enable rotation of the camshaft 36, each member 32, 34, is provided with a bushing 38 that are coaxially Al arranged. As visible on the figure the camshaft 36 has one cam 40 arranged between the members 32, 34.
The non-represented part of the pump 18 comprises the piston cooperating with the cam 40 to reciprocally slide along a second axis A2 within a bore wherein it pressurizes fuel in a compression chamber.
As indicated by the arrows, part of the fuel creates a low pressure back flow F that wets the camshaft 36 then divides into a front back flow FF and a rear back flow FR,
going through the bushings 38 lubricating the rotating surfaces. Hydraulic waves propagate in said back flows generating undesired pulsations in the low pressure return line.
There are various reasons for pressure oscillations in the low pressure circuit. The main reason is the movement of the camshaft 36 with the associated movement of fluid. This fluid under motion leads to various reflections and wherever the free flow is hindered by geometrical obstacles, pressure spikes appear and are immediately transmitted throughout the low pressure circuit.
To overcome these undesirable effects, the camshaft 36 is provided with a fluid damper 42. The camshaft 36 is manufactured partially hollow, said hollow part 44 axially Al extending inside the camshaft 36 from approximately half the middle of the camshaft 36 to the right extremity of the camshaft 36 where it opens in the rear back flow FR. As visible, the blind end of the hollow cylinder 44 is between the bushings 38 and, the hollow cylinder 44 is in fluid communication with the interior of the pump 10 via a channel 46 extending from the hollow cylinder 44, in the vicinity of said blind end, to the outer surface of the camshaft 36. Inside the hollow cylinder is arranged a transversal elastic membrane 48, for instance a thin sheet of metal laser welded on the shaft, which divides the hollow cylinder 44 into a first chamber 50, where are the blind end and the channel 46, and a second chamber 52 represented on the right of the membrane 48. The membrane 48 is normally plane in a rest position and, should it deform, its elastic properties solicit it permanently to return to said plane rest position.
In operation the inside of the first chamber 50 is filled with fuel. The hydraulic waves propagate along the back flow F enter the channel 46, get in the first chamber 50 and deform the membrane 48 varying the volume and damping the hydraulic pulsations of the flow. The total volume of the two chambers remains constant.
Numerous alternatives to this embodiment can be made. For instance in this first embodiment the right extremity of the hollow cylinder 44 cylinder is open, filled with fuel and when the membrane deforms, fuel is expelled from the second chamber. Alternatively, the membrane can be arranged at the right extremity of the hollow part, as shown in figure 4, the first chamber taking all the volume of the hollow part.
In another embodiment, the right extremity of the hollow part may be closed, and the membrane be installed, as in figure 2, inside the hollow part. The second chamber 52 is then filled with air, or another gas. In operation, the membrane 48 deforms and slightly compresses the gas in the second chamber 52.
On figure 2, the first chamber 50 is smaller than the second chamber 52, in other alternatives, the reverse can be made with the first chamber 50 being larger than the second chamber 52, said second chamber 52 being open or closed.
To fixedly arrange the membrane in place, laser welding, as well as other technologies, can be utilized.
Another embodiment is sketched on figure 3. In said embodiment the membrane 48 has been replaced by a sliding piston 54 that is permanently solicited in a rest position by a spring 56 arranged in the second chamber 52. Here again the hydraulic waves displace the piston varying the volume of the chambers 50, 52.
In any embodiment, the camshaft 36 can be mono-bloc, made of one piece, or can be composite, made of a cylindrical axle shaft over which is fixedly arranged, for instance by, a cam. An advantage of the latter construction is to utilize for the axle shaft a lower grade steel than what is used for the cam. In this case manufacturing the hollow cylinder may be easier.
above description the following references have been utilized:
8 vehicle
10 engine
12 fuel equipment
14 fuel tank
16 low pressure pump
18 high pressure pump
20 common rail
22 injectors
24 low pressure supply line
26 high pressure circuit
28 low pressure return line
30 body of the high pressure pump
32 left member of the body
34 right member of the body
36 camshaft
38 bushing
40 cam
42 damper
44 hollow part of the camshaft
46 channel
48 membrane
50 first chamber
52 second chamber
54 piston
56 spring
Al first axis
A2 second axis
F back flow of fuel
FF front back flow
FR rear back flow
Claims
1. Fuel pump (18) comprising a fixed body (30) receiving between rotational guiding means, such as bushings (38), a camshaft (36) cooperating with a piston slidably guided within a bore, the camshaft (36) being adapted to rotate and actuate the piston to reciprocally move within the bore in order to pressurize fuel within a compression chamber, characterized in that
the camshaft (36) is provided with an integral fluid damper (42) adapted to damp hydraulic waves propagating in the fluid wetting the camshaft (36) and, flowing through the rotational guiding means (38).
2. Fuel pump (18) as set in the preceding claim wherein the camshaft (36) is partially hollow, the fluid damper (42) being arranged inside the hollow part (44).
3. Fuel pump (18) as set in claim 2 wherein the camshaft (36) is further provided with a channel (46) extending through the wall of the camshaft (36) establishing a fluid communication between the external surface of the camshaft (36) and the internal hollow part (44).
4. Fuel pump (18) as set in claim 3 wherein the damper (42) comprises a deformable partition (48, 54) member arranged in the hollow part (44) so that the partition (48, 54) deformations enable to absorb the hydraulic waves by varying the volume of a first chamber (50) wherein opens the communication channel (46).
5. Fuel pump (18) as set in claim 4 wherein the deformable partition member (48) is arranged inside the hollow part (44), separating the hollow part (44) into the first chamber (50) and a second chamber (52).
6. Fuel pump (18) as set in any of the claims 4 or 5 wherein the second chamber (52) is open in fluid communication with the fluid flow (FR).
7. Fuel pump (18) as set in any of the claims 4 or 5 wherein the second chamber (52) is closed.
8. Fuel pump (18) as set in claim 4 wherein the deformable partition (48) is arranged at the extremity of the hollow part (44), the volume of the first chamber (50) being equal to the volume of the hollow part (44).
9. Fuel pump (18) as set in any of the claims 4 to 8 wherein, in absence of hydraulic waves, the partition (48, 54) remains in a rest position and, when hydraulic waves occur, the partition (48, 54) deforms or displaces away from said rest position.
10. Fuel pump (18) as set in claim 8 wherein the partition (48) is a deformable elastic membrane (48).
11. Fuel pump (18) as set in claim 9 wherein the membrane is a thin metal sheet.
12. Fuel pump (18) as set in claim 8 wherein the damper (42) is cylindrical and the partition is a piston (54) slidably guided in said cylindrical shape, a spring (56) soliciting the piston (54) toward a rest position.
13. Fuel pump (18) as set in any of the preceding claim, wherein the camshaft (36) is a composite shaft comprising a cylindrical axle shaft over which is fixedly press fitted a cam.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB1400864.3A GB201400864D0 (en) | 2014-01-20 | 2014-01-20 | High pressure fuel pump |
PCT/EP2014/076371 WO2015106876A1 (en) | 2014-01-20 | 2014-12-03 | High pressure fuel pump |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3097304A1 true EP3097304A1 (en) | 2016-11-30 |
Family
ID=50239142
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP14805942.1A Withdrawn EP3097304A1 (en) | 2014-01-20 | 2014-12-03 | High pressure fuel pump |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP3097304A1 (en) |
KR (1) | KR20160108350A (en) |
GB (1) | GB201400864D0 (en) |
WO (1) | WO2015106876A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB201511315D0 (en) * | 2015-06-29 | 2015-08-12 | Delphi Int Operations Lux Srl | Fluid pump |
CN105156173B (en) * | 2015-09-29 | 2017-10-31 | 东风商用车有限公司 | Lubricating oil circuit system of combined camshaft valve actuating mechanism |
KR102432174B1 (en) * | 2020-12-04 | 2022-08-12 | 주식회사 현대케피코 | High pressure fuel pump with fluid spring |
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JP2002349672A (en) * | 2001-05-29 | 2002-12-04 | Mitsubishi Motors Corp | Noise reduction device of gear |
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JP3422528B2 (en) * | 1992-08-17 | 2003-06-30 | フオルクスワーゲン・アクチエンゲゼルシヤフト | Camshaft device having at least one cam supported on a shaft for limited swinging |
DE19720899A1 (en) * | 1996-05-31 | 1997-12-04 | Volkswagen Ag | Camshaft for automotive engine valves |
FR2863316B1 (en) * | 2003-12-04 | 2007-12-28 | Renault Sas | PRESSURE WAVE DAMPING DEVICE IN A DRIVE AND FUEL INJECTION INSTALLATION EQUIPPED WITH SUCH A DEVICE |
US7497202B2 (en) * | 2004-10-15 | 2009-03-03 | Robert Bosch Gmbh | Hydraulic damper element |
JP5912543B2 (en) * | 2012-01-10 | 2016-04-27 | ダイムラー・アクチェンゲゼルシャフトDaimler AG | Viscous damper mounting structure for supply pump of common rail fuel injection system |
DE102012210795B3 (en) * | 2012-06-26 | 2013-09-19 | Schaeffler Technologies AG & Co. KG | Pressure accumulator for e.g. balancing operational pressure fluctuation in line system of internal combustion engine, has locking device that is provided with locking pipe which is connected with piston |
US9074565B2 (en) * | 2012-07-16 | 2015-07-07 | Denso International America, Inc. | Damped fuel delivery system |
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2014
- 2014-01-20 GB GBGB1400864.3A patent/GB201400864D0/en not_active Ceased
- 2014-12-03 KR KR1020167019129A patent/KR20160108350A/en not_active Application Discontinuation
- 2014-12-03 WO PCT/EP2014/076371 patent/WO2015106876A1/en active Application Filing
- 2014-12-03 EP EP14805942.1A patent/EP3097304A1/en not_active Withdrawn
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JP2002349672A (en) * | 2001-05-29 | 2002-12-04 | Mitsubishi Motors Corp | Noise reduction device of gear |
Non-Patent Citations (1)
Title |
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Also Published As
Publication number | Publication date |
---|---|
GB201400864D0 (en) | 2014-03-05 |
WO2015106876A1 (en) | 2015-07-23 |
KR20160108350A (en) | 2016-09-19 |
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