GB2291470A

GB2291470A - Fuel injected two-stroke engine fuel system

Info

Publication number: GB2291470A
Application number: GB9510492A
Authority: GB
Inventors: David J Hall; Gregory J Binversie; Wolfram Hellmich
Original assignee: Outboard Marine Corp
Current assignee: Outboard Marine Corp
Priority date: 1994-07-18
Filing date: 1995-05-24
Publication date: 1996-01-24
Also published as: BE1008541A6; FR2722542A1; GB9510492D0; ITRM950492A0; CA2150324A1; DE19525096A1; AU2014895A; SE9502591L; SE9502591D0; ITRM950492A1; JPH0861177A

Description

2291470 FUEL SYSTEM FOR FUEL INJECTED TWO STROKE ENGINE

BACKGROUND OF THE INVENTION

The invention relates generally to two stroke fuel injected internal combustion engines and, in particular, to fuel systems therefor.

Attention is directed to the following United States Patents:

4,093,403 4,096,692 4,395,995 4,562,820 4,732,131 5,137,002 Schrimpf et al. Nakamura et al. Crain Jiminez Hensel Mahoney et al.

SUMMARY OF THE INVENTION

The invention provides a fuel supply system for an internal combustionengine comprising a remote fuel tank, a first crankcase operated fuel pump including a fuel pumping chamber having a fuel inlet communicating with the fuel tank and a fuel outlet, a vapor separator including a fuel inlet communicating with the outlet of the first fuel pump, a fuel vapor outlet, a liquid fuel outlet, and a return fuel inlet, a second crankcase operated fuel pump including a fuel inlet communicating with the outlet of the vapor separator, and a fuel outlet, and a fuel injector including a nozzle adapted to communicate with a combustion chamber, a fuel inlet communicating with the fuel outlet of the second fuel pump, and a return outlet communicating with the return fuel inlet of the vapor separator.

The invention also provides a fuel supply system for an internal combustion engine comprising a remote fuel tank, a first crankcase operated fuel pump including a diaphragm defining a pressure chamber adapted to be connected to a source of pulsating pressure and a fuel pumping chamber having a fuel inlet communicating with the fuel tank and a fuel outlet, a vapor separator including a fuel inlet communicating with the outlet of the first fuel pump, a fuel vapor outlet, a liquid fuel outlet, and a return fuel inlet, a second crankcase operated fuel pump including a diaphragm defining a pressure chamber adapted to be connected to a source of pulsating pressure and a fuel pumping chamber including a fuel inlet communicating with the outlet of the vapor separator, and a fuel outlet, a link connecting the diaphragms for common movement, and a fuel injector including a nozzle adapted to communicate with a combustion chamber, a fuel inlet communicating with the fuel outlet of the second fuel pump, and a return outlet communicating with the return fuel inlet of the vapor separator.

other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.

1 t bl 4 T' DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic view of a fuel supply system embodying various of the features of the invention.

Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

GENERAL DESCRIPTION

Shown in the drawings is a fuel supply system 11 for an internal combustion engine (not shown). The system 11 includes first and second crankcase pressure operated fuel pumps 13 and 15 which can-be of any suitable construction and which respectively include diaphragms 17 which define respective pressure chambers 21 and fuel pumping chambers 23, and which are connected for common movement by a suitable link or member 18. The pressure chambers 21 are respectively connected by conduits or ducts 24 to an appropriate crankcase (not shown) of the associated two stroke engine. Each of the fuel pumping chambers 23 includes a fuel inlet 25 and a fuel outlet 27.

The system 11 also includes a fuel tank 41 which can be of any suitable construction and which is located remotely from the first fuel pump 13 and which is connected to the fuel inlet 25 of the first fuel pump 13 by a conduit or fuel line 43.

The system 11 also includes a vapor separator 51 which can be of any suitable construction and which comprises a tank or container 53 and includes a fuel inlet 55 located near the top of the tank 53, a liquid fuel outlet 57 located near the bottom of the tank 53, a fuel vapor outlet 59 located at the top of the tank 53, and a return fuel inlet 61 located midway between the top and bottom of the tank 53.

The fuel inlet 55 is connected by a conduit or fuel line 63 to the fuel outlet 27 of the first fuel pump 13. The liquid fuel outlet 57 is connected by a conduit or fuel line 65 with the fuel inlet 25 of the second fuel pump 15. The fuel vapor outlet 59 is connected by a suitable conduit or duct 67 to the air intake (not shown) of the associated engine.

The system 11 also includes a plurality of fuel injectors 71 which can be of any suitable construction and which respectively includes a nozzle 72 adapted to supply fuel to a combustion chamber (not shown), a fuel inlet 73 connected by a conduit or fuel line 75 with the fuel outlet 27 of the second fuel pump 15, and a fuel return outlet 77 connected by a conduit or fuel line 79 to the return fuel inlet 61 of the vapor separator 51.

In operation, the pulsing pressures produced in the crankcase of the associated two stroke engine are applied to the pressure chambers 21 of the fuel pumps 13 and 15 to cause reciprocation of the diaphragms 17 to cause fuel pumping by the first fuel pump 13 from the remote fuel tank 41 to the fuel inlet 55 of the vapor separator 51. Such reciprocation of the diaphragms 17 also causes operation of the second pump 15 to draw (solid) liquid fuel (without vapor) from the tank 53 of the vapor separator 51 and to deliver such fuel to the fuel inlets 73 of the fuel injectors 71 at an increased pressure of approximately 10 lbs. pressure. Fuel which is in excess of that required by the nozzles 72 of the fuel injectors 71 is returned to the tank 53 of the vapor separator 51 through the fuel return line 79. Such recirculation of excess fuel serves to cool the fuel injectors 71.

As a consequence of the above construction, the first fuel pump 13 is capable of lifting fuel from the remote tank 41 and of delivering such fuel at relatively low pressure to the vapor separator 51 which serves to effect removal from the fuel of any vapor so that fuel delivered to the fuel injectors 71 from the second fuel pump 15 is solid, i.e. is without vapor. Furthermore, the second fuel pump 15 sufficiently additionally pressurizes the fuel such that formation of fuel vapor is substantially prevented. In addition, as already pointed out, the system 11 is designed such that excess fuel is delivered to the fuel injectors 71, thus providing a flow of fuel which recirculates or returns to the vapor separator 71 and which serves to cool the fuel injectors 71. Such cooling also serves to minimize the possibility of the reformation of fuel vapor.

Various of the features of the invention are set forth in the following claims.

Claims

THE CLAIMS

1. A fuel supply system for an internal combustion engine comprising a remote fuel tank, a first crankcase operated fuel pump including a fuel pumping chamber having a fuel inlet communicating with said fuel tank and a fuel outlet, a vapor separator including a fuel inlet communicating with said outlet of said first fuel pump, a fuel vapor outlet, a liquid fuel outlet, and a return fuel inlet, a second crankcase operated fuel pump including a fuel inlet communicating with said outlet of said vapor separator, and a fuel outlet, and a fuel injector including a nozzle adapted to communicate with a combustion chamber, a f uel inlet communicating with said f uel outlet of said second fuel pump, and a return outlet communicating with said return fuel inlet of said vapor separator.

2. A fuel supply system in accordance with Claim 1 wherein said first and second fuel pumps respectively include diaphragms which are connected by a link for common movement.

3. A fuel supply system in accordance with Claim 1 and further including a plurality of said fuel injectors.

4. A fuel supply system for an internal combustion engine comprising a remote fuel tank, a first crankcase operated fuel pump including a diaphragm defining a pressure chamber adapted to be connected to a source of pulsating pressure and a fuel pumping chamber having a fuel inlet communicating with said fuel tank, and a fuel outlet, a vapor separator including a fuel inlet communicating with said outlet of said first fuel pump, a fuel vapor outlet, a liquid fuel outlet, and a return fuel inlet, a second crankcase operated fuel pump including a diaphragm defining a pressure chamber adapted to be connected to a source of pulsating pressure and a fuel pumping chamber including a fuel inlet communicating with said outlet of said vapor separator, and a fuel outlet, a link connecting said diaphragms for common movement, and a fuel injector including a nozzle adapted to communicate with a combustion chamber, a fuel inlet communicating with said fuel outlet of said second fuel pump, and a return outlet communicating with said return fuel inlet of said vapor separator.

5. A fuel supply systern substantially as hereinbefore described with reference to the accompanying drawing.