GB2571934A - High pressure multi-mode fuel pump system - Google Patents
High pressure multi-mode fuel pump system Download PDFInfo
- Publication number
- GB2571934A GB2571934A GB1803877.8A GB201803877A GB2571934A GB 2571934 A GB2571934 A GB 2571934A GB 201803877 A GB201803877 A GB 201803877A GB 2571934 A GB2571934 A GB 2571934A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cam
- lifter
- plunger
- mode
- lobe
- 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- Withdrawn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
-
- 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
- F02M59/10—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 characterised by the piston-drive
- F02M59/102—Mechanical drive, e.g. tappets or cams
-
- 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
- F02M59/20—Varying fuel delivery in quantity or timing
- F02M59/30—Varying fuel delivery in quantity or timing with variable-length-stroke pistons
-
- 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
- F02M2700/00—Supplying, feeding or preparing air, fuel, fuel air mixtures or auxiliary fluids for a combustion engine; Use of exhaust gas; Compressors for piston engines
- F02M2700/13—Special devices for making an explosive mixture; Fuel pumps
- F02M2700/1317—Fuel pumpo for internal combustion engines
- F02M2700/1376—Fuel pump with control of the pump piston stroke
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
A high pressure fuel pump system includes a camshaft driven plunger 10 for pressurising fuel in a pumping chamber 21, the camshaft 2 having first and second cam lobes 3,4 having different profiles which are selectively engaged to drive said plunger to provide two different pump capacities depending on operating conditions. The first cam lobe 4 may have a higher profile for operation in eg GDi mode (high fuel pressure), the second cam having a lower profile eg for PFi mode (low fuel pressure/CNG pressure). The plunger 24 may be driven via a two-stage lifter 25 having inner and outer components 8, 9 which can be locked together by movable pins 6 for the high capacity mode (fig.1a), or unlocked for the low capacity mode, as shown.
Description
HIGH PRESSURE MULTI-MODE FUEL PUMP SYSTEM
TECHNICAL FIELD
This invention relates to high pressure fuel pump systems and has particular application to cam driven piston (plunger) type pumps where fuel in a pumping chamber is pressurised as a result of the reciprocation of a cam driven plunger.
BACKGROUND OF THE INVENTION
High Pressure Pumps are used to generate sufficient fuel pressures for fuel systems, such as gasoline direct injection (GDi) systems. These usually comprise plunger type pumps which are typically driven via a dedicated cam profile acting on a roller lifter directly from the engine camshaft. To generate the pressure required for gasoline GDi systems (coming form 70 bar in the 1990’s to 350 bar today, and further increases in the pipeline); high force levels are needed to actuate the pump plunger, and thus act on the pump cam/roller drive. Further a high pump plunger lift is needed to provide a sufficient volume of fuel at these high pressures to the injectors via the fuel rail.
A problem results from the fact that the fuel demand of an engine varies significantly, e.g. low at idle and high on hefty acceleration or fast highway drive, the pump needs to deliver ever changing amounts of fuel. State of the art pumps always have a constant pump stoke, and a spill valve controls how much of each pump stroke is used to generate flow and pressure. The pump capacity (plunger surface area times plunger stroke) is derived from the maximum engine fuel demand.
Such High Pressure Pump capacity (plunger surface area times pump stroke) is derived from the maximum engine fuel demand. But for the majority of engine operating conditions, this high fuel demand is not required. An extreme case is in duel—fuel engines, which switch operation modes between GDi (high fuel pressure) and PFi (low fuel/CNG pressure), depending on engine running conditions. When operating in PFi mode, no fuel demand at all exists for the High Pressure (HP) fuel pump.
These operating conditions, in which either low or zero HP pump capacity is required cause parasitic losses, unnecessary loads on the pump drive with increased loads and potentially noise in the valve train, fuel heating up to the point of potential damage to coatings, risk of vapour lock, and unnecessary high pulsations back to the low pressure fuel side resulting also potentially into noise problems.
It is an object of the invention to overcome these problems.
SUMMARY OF THE INVENTION
In one aspect is provided A high pressure fuel pump system including a camshaft driven plunger, said plunger adapted to pressurise fuel in a pumping chamber, said camshaft including at least a first and second cam lobes having first and second cam profiles respectively, and said cam profiles being different, and wherein said cam lobes are adapted to be selectively engaged to drive said plunger.
Said first cam lobe may have a higher profile than said second cam lobe and where the system is adapted to be selectively operated in a first high power mode where said plunger is driven by said first cam lobe and in a second low power mode where said plunger is driven by said second cam lobe.
The system may include first and second cam lifters where in said second mode said second cam lobe is adapted to drive said plunger via said first cam lifter, in said first mode said first cam lobe is adapted to drive said plunger via said second cam lifter and said first cam lifter.
The systems may have means to selectively engage and disengage said first cam lifter and said second cam lifter, such that in said first mode said first cam lifter is rigidly fixed to said second cam lifter and in said second mode said second cam lifter is allowed to move relative to said first cam lifter in an axial direction..
Said plunger may include spring means to urge said plunger in an axial direction distally such that it is in contact with the in first cam lifter, and urging said first cam lifter it in a distal direction.
said first mode said first cam lifter forces said second cam lifter to a distal direction so as to engage the second cam lifter with said first cam lobe.
The system may include spring means adapted to urged said first cam lifter in an axial direction such that in said second mode said first cam lifter is allowed to move distally relative to said second cam lifter to engage said first cam lifter into contact with said second cam lobe.
Said means to selectively engage and disengage said first cam lifter and said second cam lifter, may comprise at least one hydraulically actuated pin adapted to move within bores in said first and second cam lifters.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is now described by way of example with reference to the accompanying drawings in which:
- Figures la and lb shows cross-sectional view of a high pressure fuel pump system in two modes.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In one aspect is provided a high pressure fuel pump system including a plunger driven pump, where the pump is operatively selectable to run in two operating modes depending on e.g. the fuel demand. So in one aspect it can run in a first mode with low (alternatively zero) or high fuel demand. Specifically the pump drive cam system used to drive the plunger can be operated so as to switch between two different plunger lifts, thus switching between two pump capacities.
In one aspect the cam drive which drives the pump plunger has two different cam profiles and the system is such that it can select which cam profile drives the plunger, depending on operating conditions such as fuel demand/engine load.
Figures la and lb shows cross-sectional view of a high pressure fuel pump systems according to one aspect; the example is shown with a 2-step flat lifter but a 2-step roller lifter would be feasible too, and more favourable for better stress robustness and lower friction.
The figures show a high pressure pump system. The top portion shows the pump portion 1 which includes a pump plunger 10 adapted to pressurise fuel in a pumping chamber 21. An outlet valve 22 and inlet valve 23 (which may be an inlet metering valve or other solenoid operated control valve) are provided to control flow of fuel into and out of the pumping chamber. The fuel is pressurised as a result of reciprocating movement of a plunger 10, which is driven by a camshaft 2. The plunger may be driven indirectly by means of a rider component. This and or the distal end of the plunger portion is referred to by reference numeral 24. . A flange 27 which is rigidly connected to the plunger systems is used with a spring 28 to urge the plunger to the distal position i.e. in the direction of arrow A.
The camshaft includes cam portions which have two different profiles, a first (larger) cam profile 4 which has a larger cam profile for high lift and a second cam profile 3 which has a smaller cam profile for lower lift. Here the camshaft includes two identical cams which have the larger cam profile, which flank a cam having a lower cam profile. It would be understood than in alternative designs , only two cams are necessary in total and one of the cams with the high profile can be eliminated with. In the design, the two flanking (high profile)cams can be regarded as a single cam. The pumping system is such that it is selectable which of the two cams/cam profiles (3 or 4) drives the piston/plunger.
The end of the plunger 24 or plunger arrangement is driven indirectly by the cam system (cam profiles) via a lifter system 25 which can be regarded as a two -step or two stage lifter, which can be selected to operate in high lift mode where the first cam profile is used to dictate plunger travel and a low lift mode where the second cam profile is used to dictate plunger travel.
The cam lifter system 25 include a first (inner) cam lifter (component) 8 which includes a recess to receive the end of the plunger 24 (e.g. the end of the plunger or a plunger rider/shoe), and which is located concentrically along the longitudinal axis of the plunger. In the . The first inner cam lifter include a proximally located flanged 26 or rim.
A second (outer) cam lifter (component) 9 is arranged concentrically around the first one as shown. The first cam lifter is urged in the direction of arrow A by the end of the plunger and the spring/flange (27/28) to ensure contact with the relevant cam/cam profile 3.
The second cam lifter component also has a recess arranged proximally. Within this recess is located a spring 29 which generally surround the main body of the first cam lift component, and engages/contacts the flange 26 of the first cam lift component at one end and the base of the recess of lift component 9 so as to force the main body of the second cam lifter also in the direction of arrow A (distally) so that the underside of the second cam lifter is also is robust contact with the cam system, relevant cam profile, in this case cam /cam profiles 4. As mentioned , the distal portion of the first cam lift component is in contact with a cam profile 3, located on the cam shaft between two identical cam profiles as shown.
The cam lifter system 25 is such that the cam lift components can be selected to move (up and down along the direction of arrow A) either independently of one another or they can be fixed such that no relative movement is allowed along the plunger longitudinal (vertical in the figures) axis.
In order to implement this a pin arrangement is used. Bores (holes) 30 are provided in the bases of the lift components and are aligned to receive one or more pins 6. The pin(s) 6 are provided which can move can be operatively selectably to be shifted along laterally along the bores (along the axis Z) in two states such that it either locks the two cam lift components together allowing no relative movement or to a position where the cam lift component can move relative to each other. The pin(s)m may be actuated by any appropriate means such as activated by a solenoid actuator. Alternatively and preferably the pin(s) is actuated hydraulically by oil pressure supplied e.g. from the engine. The pin may be urged into a position to the left or the right (e.g. by spring means 7) to either have the pin in a position where the cam lifters are locked together or to a position where they can move relative to each other. There may be one or more locking pins. In the examples of figures there are two locking pins.
Specifically lifter and the system is shown in high lift mode in figure la. In the example of the figures the pins are actuated by oil pressure. Oil may be supplied to activate the pin (against the force of the spring 7) from a first to a second position by appropriate control valve mean 5. Here oil pressure to the locking pins 6 is turned OFF via oil control valve 5, thus the locking pins driven are urged by a spring 7 to their default, locked, position. In this position the outer lifter 9 is locked to the inner lifter 8, thus inner and outer lifter are forced to follow the larger cam profile 4 together driving the plunger 10 of the high pressure pump 1 to a high lift, high pump capacity.
In Figure lb the system is shown in low lift mode. Oil pressure to the locking pin(s) 6 is turned ON via oil control valve 5, thus the locking pins pushed against spring 7 to their unlocked position. In this position the outer lifter 9 is able to move axially independently relative to the inner lifter 8, thus the outer lifter is idling against spring 11 following the larger cam profile 4, and the inner lifter 8 being able to follow independently the low lift cam 3 driving the plunger 10 of the high pressure pump 1 to a low lift; low pump capacity.
Claims (8)
1. A high pressure fuel pump system including a camshaft driven plunger, said plunger adapted to pressurise fuel in a pumping chamber, said camshaft including at least a first and second cam lobes having first and second cam profiles respectively, and said cam profiles being different, and wherein said cam lobes are adapted to be selectively engaged to drive said plunger.
2. A system as claimed in claim 1 where said first cam lobe has a higher profile than said second cam lobe and where the system is adapted to be selectively operated in a first high power mode where said plunger is driven by said first cam lobe and in a second low power mode where said plunger is driven by said second cam lobe.
3. A system as claimed in claims 1 or 2 including a first and second cam lifters where in said second mode said second cam lobe is adapted to drive said plunger via said first cam lifter, in said first mode said first cam lobe is adapted to drive said plunger via said second cam lifter and said first cam lifter.
4. A system as claimed in claims 1 to 3 having means to selectively engage and disengage said first cam lifter and said second cam lifter, such that in said first mode said first cam lifter is rigidly fixed to said second cam lifter and in said second mode said second cam lifter is allowed to move relative to said first cam lifter in an axial direction..
5. A system as claimed in claim 4 wherein said plunger includes spring means to urge said plunger in an axial direction distally such that it is in contact with the in first cam lifter, and urging said first cam lifter it in a distal direction.
6. A system as claimed in claims 1 to 4 where in said first mode said first cam lifter forces said second cam lifter to a distal direction so as to engage the second cam lifter with said first cam lobe.
7. A system as claimed in claims 1 to 6 including spring means adapted to urged said first cam lifter in an axial direction such that in said second mode said first cam lifter is allowed to move distally relative to said second cam lifter to engage said first cam lifter into contact with said second cam lobe.
5
8. A system as claimed in claims 1 to 7 where said means to selectively engage and disengage said first cam lifter and said second cam lifter, comprises at least one hydraulically actuated pin adapted to move within bores in said first and second cam lifters.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1803877.8A GB2571934A (en) | 2018-03-12 | 2018-03-12 | High pressure multi-mode fuel pump system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1803877.8A GB2571934A (en) | 2018-03-12 | 2018-03-12 | High pressure multi-mode fuel pump system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201803877D0 GB201803877D0 (en) | 2018-04-25 |
| GB2571934A true GB2571934A (en) | 2019-09-18 |
Family
ID=61972988
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1803877.8A Withdrawn GB2571934A (en) | 2018-03-12 | 2018-03-12 | High pressure multi-mode fuel pump system |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2571934A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3964704A1 (en) * | 2020-09-04 | 2022-03-09 | Renault s.a.s | High-pressure pump and assembly for direct and indirect injection of fuel(s) comprising a function for shutting down the high-pressure pump |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB277678A (en) * | 1926-09-18 | 1928-01-12 | Gen Electric | Improvements in or relating to regulating devices for internal combustion engines |
| DE102007062179A1 (en) * | 2007-12-21 | 2009-06-25 | Robert Bosch Gmbh | High pressure fuel pump for operating internal-combustion engine, has polygon-shaped component moved axially by adjustment unit that is vertical with respect to direction of stroke of pump piston, to obtain variation in stroke of piston |
| DE102010027443A1 (en) * | 2010-07-17 | 2011-04-21 | Daimler Ag | Pump device i.e. fuel high-pressure pump for internal combustion engine in motor vehicle, has actuator exhibiting actuating parts that cause different strokes of conveying element, and shaft driving one part for causing different strokes |
| FR2998929A1 (en) * | 2012-11-30 | 2014-06-06 | Valeo Sys Controle Moteur Sas | Pump i.e. high pressure pump for use as injector to inject e.g. petrol, into combustion chamber of heat engine in automobile field, has transmission system transmitting movement of cams to piston and varying value of cubic capacity of pump |
| KR20150062504A (en) * | 2013-11-29 | 2015-06-08 | 주식회사 현대케피코 | Apparatus for driving the high pressure fuel pump |
| US20170184064A1 (en) * | 2015-12-24 | 2017-06-29 | Audi Ag | Fuel pump |
-
2018
- 2018-03-12 GB GB1803877.8A patent/GB2571934A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB277678A (en) * | 1926-09-18 | 1928-01-12 | Gen Electric | Improvements in or relating to regulating devices for internal combustion engines |
| DE102007062179A1 (en) * | 2007-12-21 | 2009-06-25 | Robert Bosch Gmbh | High pressure fuel pump for operating internal-combustion engine, has polygon-shaped component moved axially by adjustment unit that is vertical with respect to direction of stroke of pump piston, to obtain variation in stroke of piston |
| DE102010027443A1 (en) * | 2010-07-17 | 2011-04-21 | Daimler Ag | Pump device i.e. fuel high-pressure pump for internal combustion engine in motor vehicle, has actuator exhibiting actuating parts that cause different strokes of conveying element, and shaft driving one part for causing different strokes |
| FR2998929A1 (en) * | 2012-11-30 | 2014-06-06 | Valeo Sys Controle Moteur Sas | Pump i.e. high pressure pump for use as injector to inject e.g. petrol, into combustion chamber of heat engine in automobile field, has transmission system transmitting movement of cams to piston and varying value of cubic capacity of pump |
| KR20150062504A (en) * | 2013-11-29 | 2015-06-08 | 주식회사 현대케피코 | Apparatus for driving the high pressure fuel pump |
| US20170184064A1 (en) * | 2015-12-24 | 2017-06-29 | Audi Ag | Fuel pump |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3964704A1 (en) * | 2020-09-04 | 2022-03-09 | Renault s.a.s | High-pressure pump and assembly for direct and indirect injection of fuel(s) comprising a function for shutting down the high-pressure pump |
| FR3113927A1 (en) * | 2020-09-04 | 2022-03-11 | Renault Sas | HIGH PRESSURE PUMP AND DIRECT AND INDIRECT FUEL INJECTION ASSEMBLY INCLUDING A HIGH PRESSURE PUMP STOPPING FUNCTION |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201803877D0 (en) | 2018-04-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| COOA | Change in applicant's name or ownership of the application |
Owner name: DELPHI AUTOMOTIVE SYSTEMS LUXEMBOURG SA Free format text: FORMER OWNER: DELPHI TECHNOLOGIES IP LIMITED |
|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |