WO2017125501A1 - Low pressure fuel delivery circuit - Google Patents

Low pressure fuel delivery circuit Download PDF

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Publication number
WO2017125501A1
WO2017125501A1 PCT/EP2017/051097 EP2017051097W WO2017125501A1 WO 2017125501 A1 WO2017125501 A1 WO 2017125501A1 EP 2017051097 W EP2017051097 W EP 2017051097W WO 2017125501 A1 WO2017125501 A1 WO 2017125501A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel
pump
inlet
fuel supply
diffuser
Prior art date
Application number
PCT/EP2017/051097
Other languages
French (fr)
Inventor
Paul Buckley
Original Assignee
Delphi International Operations Luxembourg S.À R.L.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Delphi International Operations Luxembourg S.À R.L. filed Critical Delphi International Operations Luxembourg S.À R.L.
Priority to EP17701454.5A priority Critical patent/EP3405667A1/en
Publication of WO2017125501A1 publication Critical patent/WO2017125501A1/en

Links

Classifications

    • 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
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/0011—Constructional details; Manufacturing or assembly of elements of fuel systems; Materials therefor
    • F02M37/0023—Valves in the fuel supply and return system
    • F02M37/0029—Pressure regulator in the low pressure fuel system
    • 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
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/02—Feeding by means of suction apparatus, e.g. by air flow through carburettors
    • F02M37/025—Feeding by means of a liquid fuel-driven jet pump
    • 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
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/04—Feeding by means of driven pumps
    • F02M37/045—Arrangements for driving rotary positive-displacement pumps

Definitions

  • This disclosure relates to systems and arrangements for fuel supply and has particular but non-exclusive application to a system adapted to provide pressurised fuel from a fuel tank to e.g. fuel injectors.
  • Typical systems used to provide high pressure fuel supply include a low pressure pump such as a gear or vane pump, adapted to pressurise fuel from a tank, and provide this pressurised fuel to a hydraulic head which includes a high pressure (e.g.
  • reciprocating plunger type pump for supply of high pressure to e.g. fuel injectors.
  • a pressure regulator is used, connected in parallel with the low pressure pump, to regulate the intermediate pressure, to provide against overpressure on the outlet side, and to reduce any high pressure peaks.
  • a by-pass valve is sometimes used to provide a path for fluid to flow from the low pressure side to the high pressure side of the fuel pump. Thus, flow can by-pass the low pressure pump.
  • the low pressure pump "draws" fuel from the tank. In practice this is by producing a vacuum at the inlet so that atmpospheric pressure can push fuel from the tank to the pump inlet. This vacuum reduces the efficiency of the low-pressure pump and can cause minor functional problem as the vacuum is dissipated throughout the system.
  • fuel pumps such as Diesel fuel pump
  • a mechanical, low- pressure pump such as a positive displacement vane-pump
  • a regulator is included to provide a modest pressure to supply the high-pressure pump.
  • the mechanical (particularly vane, but also gear) pumps typically used are of conventional design and normally have a much larger swept volume than the high-pressure pump.
  • the regulator is usually of conventional design dominated by a spool valve actuated by pressure and a regulating spring. The regulator wastes excess output back to the pump inlet in conventional fashion. It is an object of the invention to overcome these and other issues.
  • a fuel supply arrangement adapted to provide pressurized fuel, comprising a fuel pump, adapted to pump fuel from a fuel supply inlet to a fuel supply outlet, and including a pressure regulator arranged in parallel with said pump, fluidly connected between said outlet and said fuel supply inlet, so as provide a recirculating flow circuit, wherein between said pump and said pressure regulator on the inlet side, is located a diffuser arrangement fluidly connecting said pump and said pressure regulator.
  • Said diffuser may be connected to said fuel supply inlet so as to receive fuel flow directly from the fuel supply inlet.
  • Said diffuser arrangement thus fluidly connects said the pump inlet and the pressure regulator on the inlet side so as provide a recirculating flow circuit.
  • the diffuser receives flow from the fuel supply inlet.
  • the diffuser arrangement fluidly connects the low side of the pressure regulator to the pump (low side) inlet, and has a third fluid connection (inlet) from a fuel supply inlet/source.
  • the diffuser arrangement preferably comprises a Venturi.
  • the fuel inlet in the fuel system/arrangement is to the diffuser/V enturi.
  • the fuel supply inlet is arranged relative to the diffuser such that flow from the fuel inlet to the diffuser enters the diffuser with a component of flow in the direction along the diffuser longitudinal axis and in a direction towards the pump inlet.
  • the fuel supply inlet flow axis may be arranged relative to the diffuser longitudinal axis at an acute angle.
  • Said fuel supply inlet may be arranged such that the diffuser arrangement receives flow from the fuel inlet at its narrow portion.
  • the narrow portion has an inlet for fuel supply
  • Figure 1 shows flow circuitry that is typically used in engine systems to provide high pressure fuel to fuel injectors from a tank;
  • Figure 2 shows a portion of a low pressure circuit of a fuel supply system incorporating one aspect.
  • Figure 1 shows flow circuitry that is typically used in engine systems to provide high pressure fuel to fuel injectors from a tank.
  • the circuitry generally comprises a high pressure portion and a low pressure portion.
  • a low pressure pump 2 such as a vane pump, is used to provide a first pressurisation.
  • the pressurised fuel then typically passes through a main filter 3 to provide low pressure feed pressure to a high pressure pump 4 such as a piston pump.
  • the flow from the main filter may be passed through an inlet metering valve 5 before passing through an inlet valve 6, the piston pump 4, and an outlet valve 7, to high pressure outlet.
  • the inlet valve, high pressure pump and outlet valve are often referred to as the hydraulic head.
  • a plunger backleak path 8 may be provided providing a high pressure pump back leak to the low pressure line via a Venturi 9.
  • a pressure regulator 10 may be included between the high pressure and low pressure pumps with also a line from the backleak.
  • the low pressure side will include a by-pass valve 11 located in parallel with the low pressure pump.
  • the by-pass valve acts to regulate LP feed pressure such that when the pressure in the LP return is greater than a set value compared with the LP feed pressure, flow will flow through the valve from the LP return pressure line to the LP feed pressure line.
  • a valve is necessary in order to provide a priming function.
  • Certain type of pumps cannot self-prime, so when filters are replaced or pumps are replaced, the bypass valve allows the entire pump to fill up with fuel and fully primed.
  • the priming function also allows the main filter to fill from the inlet side.
  • a pressure regulator 12 pressure regulation valve
  • LP feed pressure line side
  • LP return pressure limits the pressure to the main filter during running of the pump.
  • Figure 2 shows an example according to one aspect. This shows a portion of a fuel supply system (low pressure circuit thereof) similar to that of figure 1 , but incorporating an example of the invention.
  • the figure shows the low pressure circuit (pump region) 13 of a fuel supply circuit in a fuel supply system for a combustion engine such as a Diesel engine.
  • the low pressure pump 2 supplies fuel from a fuel tank (not shown) via a fuel inlet, to a high pressure pump (not shown).
  • a pressure regulator 12 In parallel with the fuel pump is located a pressure regulator 12.
  • the pressure regulator 12 provides a return circuit to allow excess flow to recirculate under high pressure conditions to the pump inlet.
  • a by-pass valve may optionally be included, arranged as in figure 1.
  • Venturi or diffuser type arrangement 14 is located between the pump inlet and the low pressure side of the pressure regulator (valve).
  • a fuel supply e.g. fuel tank
  • the flow circuit is adapted so as to pass the recirculating flow through a Venturi/diffuser component.
  • the pump inlet is preferably connected to the throat (narrow portion) of the Venturi/diffuser to augment the vacuum to draw fuel through the filter.
  • the expansion recovers pressure to reduce the depth of vacuum inside the mechanical pump. No additional flow is required.
  • the filter, mechanical pump and regulator perform in conventional manner.
  • the recirculating flow has the effects described above. In practice pressures and flows form an equilibrium operating point. The indicated pressures are relative to this new equilibrium point. The effect of the diffuser will, therefore, partly augment the vacuum in the throat 15 and partly increase the pressure at the low-side of the pump 2.
  • the inlet is preferably arranged at an acute angle with respect to the longitudinal axis XX of the Venturi, to favour the flow direction through the Venturi rather than being perpendicular thereto.
  • flow from the inlet enters the Venturi with a component of flow along the Venturi axis and in a direction towards the pump inlet to assist the flow.

Abstract

A fuel supply arrangement adapted to provide pressurized fuel, comprising a fuel pump, adapted to pump fuel from a fuel supply inlet to a fuel supply outlet, and including a pressure regulator arranged in parallel with said pump, fluidly connected between said outlet and said fuel supply inlet, so as provide a recirculating flow circuit, wherein between said pump and said pressure regulator on the inlet side, is located a diffuser arrangement fluidly connecting said pump and said pressure regulator. The diffuser is preferably connected to said fuel supply inlet so as to receive fuel flow directly from the fuel supply inlet.

Description

LOW PRESSURE FUEL DELIVERY CIRCUIT FIELD OF THE INVENTION
This disclosure relates to systems and arrangements for fuel supply and has particular but non-exclusive application to a system adapted to provide pressurised fuel from a fuel tank to e.g. fuel injectors. BACKGROUND TO THE INVENTION
Typical systems used to provide high pressure fuel supply (e.g. to fuel injectors) include a low pressure pump such as a gear or vane pump, adapted to pressurise fuel from a tank, and provide this pressurised fuel to a hydraulic head which includes a high pressure (e.g.
reciprocating plunger type) pump for supply of high pressure to e.g. fuel injectors.
In such systems, typically a pressure regulator is used, connected in parallel with the low pressure pump, to regulate the intermediate pressure, to provide against overpressure on the outlet side, and to reduce any high pressure peaks. In addition, a by-pass valve is sometimes used to provide a path for fluid to flow from the low pressure side to the high pressure side of the fuel pump. Thus, flow can by-pass the low pressure pump.
The low pressure pump "draws" fuel from the tank. In practice this is by producing a vacuum at the inlet so that atmpospheric pressure can push fuel from the tank to the pump inlet. This vacuum reduces the efficiency of the low-pressure pump and can cause minor functional problem as the vacuum is dissipated throughout the system.
So to recap, fuel pumps (such as Diesel fuel pump) often incorporate a mechanical, low- pressure pump (such as a positive displacement vane-pump) to "draw" fuel from the tank and through the fuel filter. A regulator is included to provide a modest pressure to supply the high-pressure pump.
The mechanical (particularly vane, but also gear) pumps typically used are of conventional design and normally have a much larger swept volume than the high-pressure pump. The regulator is usually of conventional design dominated by a spool valve actuated by pressure and a regulating spring. The regulator wastes excess output back to the pump inlet in conventional fashion. It is an object of the invention to overcome these and other issues. STATEMENT OF INVENTION
In one aspect is provided a fuel supply arrangement adapted to provide pressurized fuel, comprising a fuel pump, adapted to pump fuel from a fuel supply inlet to a fuel supply outlet, and including a pressure regulator arranged in parallel with said pump, fluidly connected between said outlet and said fuel supply inlet, so as provide a recirculating flow circuit, wherein between said pump and said pressure regulator on the inlet side, is located a diffuser arrangement fluidly connecting said pump and said pressure regulator.
Said diffuser may be connected to said fuel supply inlet so as to receive fuel flow directly from the fuel supply inlet.
Said diffuser arrangement thus fluidly connects said the pump inlet and the pressure regulator on the inlet side so as provide a recirculating flow circuit.
Preferably the diffuser receives flow from the fuel supply inlet. So in other words, in an example the diffuser arrangement fluidly connects the low side of the pressure regulator to the pump (low side) inlet, and has a third fluid connection (inlet) from a fuel supply inlet/source.
The diffuser arrangement preferably comprises a Venturi.
Thus in an example the fuel inlet in the fuel system/arrangement is to the diffuser/V enturi. Preferably the fuel supply inlet is arranged relative to the diffuser such that flow from the fuel inlet to the diffuser enters the diffuser with a component of flow in the direction along the diffuser longitudinal axis and in a direction towards the pump inlet.
The fuel supply inlet flow axis may be arranged relative to the diffuser longitudinal axis at an acute angle.
Said fuel supply inlet may be arranged such that the diffuser arrangement receives flow from the fuel inlet at its narrow portion. For example the narrow portion has an inlet for fuel supply
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be described by way of example and with reference to the following figures of which:
Figure 1 shows flow circuitry that is typically used in engine systems to provide high pressure fuel to fuel injectors from a tank;
Figure 2 shows a portion of a low pressure circuit of a fuel supply system incorporating one aspect. DETAILED DESCRIPTION OF THE INVENTION
Figure 1 shows flow circuitry that is typically used in engine systems to provide high pressure fuel to fuel injectors from a tank. The circuitry generally comprises a high pressure portion and a low pressure portion.
Fuel from a tank (not shown) enters a low pressure pump inlet and enters a pre-filtering stage comprising pre- filter 1. A low pressure pump 2, such as a vane pump, is used to provide a first pressurisation. The pressurised fuel then typically passes through a main filter 3 to provide low pressure feed pressure to a high pressure pump 4 such as a piston pump. The flow from the main filter may be passed through an inlet metering valve 5 before passing through an inlet valve 6, the piston pump 4, and an outlet valve 7, to high pressure outlet. The inlet valve, high pressure pump and outlet valve are often referred to as the hydraulic head. A plunger backleak path 8 may be provided providing a high pressure pump back leak to the low pressure line via a Venturi 9. A pressure regulator 10 may be included between the high pressure and low pressure pumps with also a line from the backleak.
Typically the low pressure side will include a by-pass valve 11 located in parallel with the low pressure pump. The by-pass valve acts to regulate LP feed pressure such that when the pressure in the LP return is greater than a set value compared with the LP feed pressure, flow will flow through the valve from the LP return pressure line to the LP feed pressure line. Such a valve is necessary in order to provide a priming function. Certain type of pumps cannot self-prime, so when filters are replaced or pumps are replaced, the bypass valve allows the entire pump to fill up with fuel and fully primed. The priming function also allows the main filter to fill from the inlet side.
Additionally a pressure regulator 12 (pressure regulation valve) is provided which regulates the pressure in the LP feed pressure line (side), between the two pumps. This dampens down any pressure spikes on the LP return pressure; thus this limits the pressure to the main filter during running of the pump.
Figure 2 shows an example according to one aspect. This shows a portion of a fuel supply system (low pressure circuit thereof) similar to that of figure 1 , but incorporating an example of the invention. The figure shows the low pressure circuit (pump region) 13 of a fuel supply circuit in a fuel supply system for a combustion engine such as a Diesel engine. The low pressure pump 2 supplies fuel from a fuel tank (not shown) via a fuel inlet, to a high pressure pump (not shown). In parallel with the fuel pump is located a pressure regulator 12. The pressure regulator 12 provides a return circuit to allow excess flow to recirculate under high pressure conditions to the pump inlet. A by-pass valve may optionally be included, arranged as in figure 1.
In the circuit shown, a Venturi or diffuser type arrangement 14 is located between the pump inlet and the low pressure side of the pressure regulator (valve).
There is an inlet 16 fluidly connected to a fuel supply (e.g. fuel tank) that connects with the narrow portion of the Venturi/ diffuser. In this way the flow circuit is adapted so as to pass the recirculating flow through a Venturi/diffuser component.
The pump inlet is preferably connected to the throat (narrow portion) of the Venturi/diffuser to augment the vacuum to draw fuel through the filter. The expansion recovers pressure to reduce the depth of vacuum inside the mechanical pump. No additional flow is required. At low speed the filter, mechanical pump and regulator perform in conventional manner. At high speeds the recirculating flow has the effects described above. In practice pressures and flows form an equilibrium operating point. The indicated pressures are relative to this new equilibrium point. The effect of the diffuser will, therefore, partly augment the vacuum in the throat 15 and partly increase the pressure at the low-side of the pump 2.
In a preferred aspect, the inlet is preferably arranged at an acute angle with respect to the longitudinal axis XX of the Venturi, to favour the flow direction through the Venturi rather than being perpendicular thereto. Thus flow from the inlet enters the Venturi with a component of flow along the Venturi axis and in a direction towards the pump inlet to assist the flow.

Claims

CLAIMS:
1. A fuel supply arrangement adapted to provide pressurized fuel, comprising a fuel pump, adapted to pump fuel from a fuel supply inlet to a fuel supply outlet, and including a pressure regulator arranged in parallel with said pump, fluidly connected between said outlet and said fuel supply inlet, so as provide a recirculating flow circuit, wherein between said pump and said pressure regulator on the inlet side, is located a diffuser arrangement fluidly connecting said pump and said pressure regulator. 2. An arrangement as claimed in claim 1 wherein said diffuser is connected to said fuel supply inlet so as to receive fuel flow directly from the fuel supply inlet.
4. An arrangement as claimed in claims 1 to 3 wherein the fuel supply inlet is arranged relative to the diffuser such that flow from the fuel inlet to the diffuser enters the diffuser with a component of flow in the direction along the diffuser longitudinal axis and in a direction towards the pump inlet.
5. An arrangement as claimed in claims 1 to 4 wherein the fuel supply inlet flow axis is arranged relative to the diffuser longitudinal axis at an acute angle.
6. An arrangement as claimed in claims 1 to 5 wherein said fuel supply inlet is arranged such that the diffuser arrangement receives flow from the fuel inlet at its narrow portion. 7. An arrangement as claimed in claims 1 to 6 wherein said diffuser arrangement comprises a Venturi.
PCT/EP2017/051097 2016-01-20 2017-01-19 Low pressure fuel delivery circuit WO2017125501A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP17701454.5A EP3405667A1 (en) 2016-01-20 2017-01-19 Low pressure fuel delivery circuit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB1601051.4A GB201601051D0 (en) 2016-01-20 2016-01-20 Low pressure fuel delivery circuit
GB1601051.4 2016-01-20

Publications (1)

Publication Number Publication Date
WO2017125501A1 true WO2017125501A1 (en) 2017-07-27

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2017/051097 WO2017125501A1 (en) 2016-01-20 2017-01-19 Low pressure fuel delivery circuit

Country Status (3)

Country Link
EP (1) EP3405667A1 (en)
GB (1) GB201601051D0 (en)
WO (1) WO2017125501A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4400958C1 (en) * 1994-01-14 1995-04-06 Bayerische Motoren Werke Ag Sucking jet pump
FR2769053A1 (en) * 1997-10-01 1999-04-02 Marwal Systems Jet pump for motor vehicle fuel supply
DE102004050991A1 (en) * 2004-10-20 2006-04-27 Robert Bosch Gmbh Device for aiding fluid has pumping unit whereby intake of fluid from storage tank is done via suction line and delivered to internal combustion engine via discharge line with first sucking jet pump, which generates pressure in pumping unit
WO2011135240A1 (en) * 2010-04-28 2011-11-03 Snecma Turbomachine fueling system with jet pump

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4400958C1 (en) * 1994-01-14 1995-04-06 Bayerische Motoren Werke Ag Sucking jet pump
FR2769053A1 (en) * 1997-10-01 1999-04-02 Marwal Systems Jet pump for motor vehicle fuel supply
DE102004050991A1 (en) * 2004-10-20 2006-04-27 Robert Bosch Gmbh Device for aiding fluid has pumping unit whereby intake of fluid from storage tank is done via suction line and delivered to internal combustion engine via discharge line with first sucking jet pump, which generates pressure in pumping unit
WO2011135240A1 (en) * 2010-04-28 2011-11-03 Snecma Turbomachine fueling system with jet pump

Also Published As

Publication number Publication date
GB201601051D0 (en) 2016-03-02
EP3405667A1 (en) 2018-11-28

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