GB2558944A

GB2558944A - Multi-fuel pump arrangement

Info

Publication number: GB2558944A
Application number: GB1701114.9A
Authority: GB
Inventors: J Lane David; Peter Keeler Nathan
Original assignee: Delphi International Operations Luxembourg SARL
Current assignee: Delphi International Operations Luxembourg SARL
Priority date: 2017-01-23
Filing date: 2017-01-23
Publication date: 2018-07-25
Also published as: GB201701114D0

Abstract

A fuel pump adapted to provide pressurised fuels of different types. The pump comprises at least one inlet and outlet for each fuel type. The pumping mechanism 5, 6 comprises cylinders 3 for the first and second fuel respectively, with plungers 4 in each cylinder. The plungers reciprocate within their sleeves to draw fuel from intake ports to discharge ports. Each of the cylinders are contained within a common housing. The pump may use a common drive system 15 for all the plungers. This may be a camshaft 14. A plurality of cam lobes 13a, 13b may be used, with different cams driving the plungers of the multiple fuels. Differing profiles may be used for the lobes. Such a pump may be used with a dual fuel engine system, such as a Westport diesel, CNG or diesel/methanol based engines. The invention aims to reduce weight, cost, packing requirements, gear train complexity and assembly line time when compared to a conventional two pump system.

Description

(71) Applicant(s):

Delphi International Operations Luxembourg S.A.R.L. (Incorporated in Luxembourg)

Avenue de Luxembourg, L-4940 Bascharage,

R.C.S. Luxembourg B 99207, Luxembourg (72) Inventor(s):

David J Lane Nathan Peter Keeler (56) Documents Cited:

CN 105221313 A CN 002926554 Y

US 3260211 A (58) Field of Search:

INT CL F02M

Other: EPODOC & WPI (74) Agent and/or Address for Service:

Delphi France SAS c/o Delphi Technologies, Campus Saint Christophe, 95863 Cergy Pontoise CEDEX,

France (including Overseas Departments and Territori es) (54) Title of the Invention: Multi-fuel pump arrangement Abstract Title: Multi-fuel piston pump (57) A fuel pump adapted to provide pressurised fuels of different types. The pump comprises at least one inlet and outlet for each fuel type. The pumping mechanism 5, 6 comprises cylinders 3 for the first and second fuel respectively, with plungers 4 in each cylinder. The plungers reciprocate within their sleeves to draw fuel from intake ports to discharge ports. Each of the cylinders are contained within a common housing.

The pump may use a common drive system 15 for all the plungers. This may be a camshaft 14. A plurality of cam lobes 13a, 13b may be used, with different cams driving the plungers of the multiple fuels. Differing profiles may be used for the lobes. Such a pump may be used with a dual fuel engine system, such as a Westport diesel, CNG or diesel/methanol based engines.

The invention aims to reduce weight, cost, packing requirements, gear train complexity and assembly line time when compared to a conventional two pump system.

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FIG. la

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FIG. lb

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FIG. 2

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MULTI-FUEL PUMP ARRANGEMENT

TECHNICAL FIELD

This disclosure relates to fuel pumps for engines, and has particular application to engine systems which use at least two different fuel types, such as “dual fuel” engine systems.

BACKGROUND OF THE INVENTION

There are engines currently on the market that have a multi-fuel setup where two separate fuel pumps are adapted to deliver fuel to two individual high pressure common rails, e.g. Westport diesel / CNG engines or diesel / methanol based engines. Using two separate fuel pumps means two pump drive interfaces are required on the engine, which increases weight, cost, packaging requirements, gear train complexity and assembly line time.

It is an object of the invention to overcome the aforesaid problems.

SUMMARY OF THE INVENTION

In one aspect is provided a fuel pump arrangement adapted to provide pressurized fuel in respect to a plurality of different fuel types, said arrangement including at least one fuel inlet and outlet for each fuel type, and pumping means adapted to pressurize fuel from said inlets to provide pressurized fuel to said outlets, where said pumping means comprises, for each fuel type, at least one cylinder and plunger arrangement which includes a cylinder, said cylinder including a fuel inlet port and a fuel outlet port, and a plunger, said plunger adapted to reciprocate within said cylinder so as draw in fuel from said respective inlet and to provide pressured fuel via said respective outlet, where each of said cylinder and plunger arrangements for each fuel type are contained within a common housing.

All of said plungers in respect of the different fuels may be driven by a common drive system.

Said common drive system may include a common camshaft.

Said common camshaft may include a plurality of cam lobes, including at least one lobe adapted to drive the respective plunger of the at least one cylinder and plunger arrangement for a first fuel type, and at least one lobe adapted to drive the respective plunger of the at least one cylinder and plunger arrangement with respect to a second fuel type.

Said lobes may have different profiles.

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 b show cross sectional and external views of a pump arrangement according to one aspect;

- Figure 2 shows a highly schematic diagram showing an embodiment of the invention

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to one aspect functionality of two separate fuel pumps are provided by one pump unit which includes a single housing.

Figure la shows a cross sectional view through a pump arrangement 1 and figure lb shows an external view, according to one aspect. The pump arrangement is adapted to supply two different fuels to fuel injectors at high pressure, which may be via common rails. The arrangement includes a housing 2 which is formed to provide a number of cylinders 3, in the example there are three cylinders. In each cylinder is located a piston 4 (often referred to as a plunger) adapted to reciprocate such that on a down stroke, fuel from a respective inlet is drawn into the cylinder and on the upstroke, fuel in the cylinder is pressurized and provided to a respective outlet. Inlet and outlet valves as are known on the art may be provided. In the example of figure la and lb, there are provided three units each of which comprise a cylinder and plunger unit (pumping module); two 5 are provided with respect to one fuel type (e.g. fuel type A) and one cylinder/plunger unit 6 for a different fuel e.g. fuel type B.

Figure lb shows an external view of the figure la design and shows the inlets for fuel types A and B respectively as reference numerals 7 and 8. Outlets from the cylinders which provide pressurized fuel (e.g. to the fuel injectors) are designated with reference numerals 9 and 10 respectively for fuel A and fuel B. The skilled person would be aware that there may be just one piston/cylinder arrangement (with respective inlet and outlet) for each fuel type; alternatively there may be more than one for each fuel type. Backflow/return to tank outlets may be provided for each fuel type 11,12. The respective pistons/plungers are driven by a common camshaft 14 having respective lobes 13a, 13b for the cylinder/pumping modules.

Figure 2 shows a highly schematic diagram showing an embodiment of the invention where there is provided a common housing incorporating two plunger/cylinder units 5,6 , one for each type of fuel; type A and type B. Alternatively as in figures la and lb there may be two plunger/cylinder units for fuel type A and one for fuel type B. The skilled person would be aware of the permutations of the number of plunger/cylinder module provided with respect of two or more fuel types. These are incorporated into a common housing (not shown).

As can be seen the plungers (pistons) 4 in each cylinder 3 are driven by a cam system 15. The plungers are (i.e. in respect of the plunger/cylinder units for the different fuels) are driven by a common camshaft 14. Located on the camshaft are cam lobes 13a and 13 b, which drive a connecting mechanism to the respective pistons/plungers in each cylinder, with respect to fuels of type A and B respectively. The cam lobes may have different profiles; in this way the pumping profile per revolution of the camshaft for different fuels (in respect to the plunger/cylinder units for these fuels), can be designed differently. So in other words the cam lobe profile for fuel A may be different of that for fuel B; in this way the pumping and pressurization profile/regime with respect to the different fuels can be controlled according to requirements but being driven by a common cam improves the efficiency in terms of space saving and costs and provides for the hereindescribed advantages of the invention.

Advantages of the engine include only requiring one drive interface (common camshaft), as well as the system having reduced weight, in contrast to prior art systems which use two separate fuel pumps. There are thus reduced packaging requirements and reduced assembly line time (only fit one pump rather than two). Furthermore the system according to embodiments requires only minimal engine adaption required for customers that are already using known systems and allow an easy upgrade path for customers who currently use a remote cambox and wish to diversify into a multi-fuel engine configuration

Claims

1. A fuel pump arrangement adapted to provide pressurized fuel in respect to a plurality of different fuel types, said arrangement including at least one fuel inlet

5 and outlet for each fuel type, and pumping means adapted to pressurize fuel from said inlets to provide pressurized fuel to said outlets, where said pumping means comprises, for each fuel type, at least one cylinder and plunger arrangement which includes a cylinder, said cylinder including a fuel inlet port and a fuel outlet port, and a plunger, said plunger adapted to reciprocate within said cylinder so as draw

10 in fuel from said respective inlet and to provide pressured fuel via said respective outlet, where each of said cylinder and plunger arrangements for each fuel type are contained within a common housing.

2. A fuel pump arrangement as claims in claim 1 where all of said plungers

15 in respect of the different fuels are driven by a common drive system.

3. An arrangement as claimed in claim 2 wherein said common drive system includes a common camshaft.

20

4. An arrangement as claimed in claim 3 where said common camshaft includes a plurality of cam lobes, including at least one lobe adapted to drive the respective plunger of the at least one cylinder and plunger arrangement for a first fuel type, and at least one lobe adapted to drive the respective plunger of the at least one cylinder and plunger arrangement with respect to a second fuel type.

5. An arrangement as claimed in claim 4 wherein said lobes have different profiles.

Intellectual

Property

Office

Application No: GB1701114.9 Examiner: Nicholas Wigley Claims searched: 1-5 Date of search: 21 June 2017