Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3817456 A
Publication typeGrant
Publication dateJun 18, 1974
Filing dateJul 17, 1973
Priority dateJul 18, 1972
Also published asDE2235083A1
Publication numberUS 3817456 A, US 3817456A, US-A-3817456, US3817456 A, US3817456A
InventorsSchlappkohl J
Original AssigneeSchlappkohl J
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Fuel injection nozzle for internal combustion engines
US 3817456 A
Abstract
A fuel-injection nozzle for an internal combustion engine is described, which nozzle comprises a valve needle for controlling the flow of fuel via a throttle passage to a pressure chamber for a preliminary fuel injection out of the nozzle and for controlling of the flow of fuel via duct means to the pressure chamber for a main fuel injection out of the nozzle, during the opening stroke of the valve needle, and which nozzle is improved by valve means closed during rest position which valve means are mounted in the duct means and associated with the valve needle to be opened by the needle during its opening stroke; the free cross-sectional area of the nozzle mouth which is traversed by the fuel during the preliminary injection is smaller than the cross-sectional area of said throttle passage.
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent n91 Schlappkohl June 18, 1974 FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES '[76] Inventor: Jorg Schlappkohl, Lindenbachstr.

43, 7 Stuttgart, Germany [22 Filed: July 17, 1973 [21] Appl. No.: 380,099

[30] Foreign Application Priority Data July 18, 1972 Germany 2235083 I 52 us. Cl. 239/533 [51] Int. Cl B05b l/30 [58] Field of Search 239/533, 126,570

[5 6] References Cited UNITED STATES PATENTS 2,556,369 6/1951 Hogeman 239/533 3,640,466 2/1972 Steiger 239/533 FOREIGN PATENTS OR APPLICATIONS 510,841

12/1952 Italy 4. 239/533 Primary Examiner-Lloyd L. King ABSTRACT A fuel-injection nozzle for an internal combustion engine is described, which nozzle comprises a valve needle for controlling the flow of fuel via a throttle passage to a pressure chamber for a preliminary fuel injection out of the nozzle and for controlling of the flow of fuel via duct means to the pressure chamber for a main fuel injection out of the nozzle, during the opening stroke of the valve needle, and which nozzle is improved by valve means closed during rest position which valve means are mounted in the duct means and associated with the valve needle to be opened by the needle during its opening stroke; the free crosssectional area of the nozzle mouth which is-traversed by the fuel during the preliminary injection is smaller than the cross-sectional area of said throttle passage.

5 Claims, 1 Drawing Figure FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION wherein a duct for the main injection of fuel is opened 1 during the opening stroke of the valve needle.

Such preand main injection valves are employed in order to reduce the loud ignition noises caused by high speed diesel engines while idling. By. means of the preinjection and main injection, of which the former preferably merges into the latter, a combustion of little noise is achieved which sets in smoothly and proceeds slowly in the beginning.

Known fuel injection valves of this type have the drawbacks of being expensive to manufacture and of having a hydrodynamically unfavorable conduit system.

OBJECTS AND SUMMARY OF THE INVENTION ls is an object of the invention to develop an inexpensive valve means for preinjection and main injection which is free from the above-described drawbacks.

This object is attained, in accordance with the invention, by providing in a fuel injection nozzle of the type initially described, a valve means interposed in the main injection fuel duct, which is in closed position during idling of the engine and which is pushed open by the valve needle during the opening stroke of the latter, and means for producing during the preinjection stroke a throttle effect which is larger at the point of fuel injection than at the throttle passage mentioned further above.

In a preferred embodiment of the invention, the valve is arranged coaxially with, the valve needle and comprises a movable valve member having a plug, and the valve needle comprises a return spring and a springretaining disc at a distance from the said plug which is as large as the preinjection opening stroke of the needle.

With such an arrangement, it is possible to manufacture an inexpensive valve which requires few closely fitting parts compared with a normal injection valve; only the throttle effect in the preinjection throttle passage and the throttle effect at the opening injection orifice must'be exactly proportioned relative to one another. Y

In another embodiment of the invention, an auxiliary pressure chamber is provided upstream of the main pressure chamber, and these pressure chambers are connected with each other 'via a throttle passage which is open at all times, and via a valve-controlled fuel line; and a movable valve member of the valve plunges into the auxiliary pressure chamber when the valve is opened against a closing force.

The invention will be better understood and further objects and advantages will become apparent from the ensuing detailed specification of a preferred but merely exemplary embodiment taken in conjunction with the drawing.

I BRIEF DESCRIPTION OF THE DRAWING The drawing shows in axial sectional view a preferred embodiment of the fuel injection nozzle according to the invention.

DETAILED DESCRIPTION OF THE EMBODIMENT In a nozzle head 1, a valve needle 2 having a throttle plug 3 is mounted to control an injection orifice 4 provided in a pressure chamber 5. The nozzle head 1 is clamped together with three super-imposed discs 8, 9 and 10 in a nozzle holder 7 by means of a clamp bolt 6. Disc 8 has a central bore 13 which houses a locking spring 11 and its spring seat disc 12. In disc 10, a second pressure chamber 14 is provided in the form of a central recess which is connected at its one side via channels 15 and 15a to a line 15b for supplying fuel from the fuel injection pump (not shown), while on its other side recess 14 communicates with pressure chamber 5, on the one hand, via a duct 16 in which throttle 18 is inserted, and which conveys a preliminary fuel amount to the pressure chamber 5, and, on the other hand, via a duct 17 controlled by a valve 19 and serving to convey the main fuel amount. Both ducts l6 and 17 extend through discs 8 and 9 into nozzle head 1. Throttle 18 is mounted in that part of duct 16 which extends through disc 9. Valve 9 comprises a movable valve member 22 which is displaceable for opening against the direction of fuel flow and is biassed by a closing spring 20, which is supported on the end wall of recess 14, so that valve member 22 moves into the recess 14 when opening.

When the injection pump conveys fuel to the nozzle, part of the fuel flows out of pressure chamber 14 and via throttle l8 and duct 16 into the pressure chamber 5, and causes the valve needle 2 to lift from its seat 40 by overcoming the force of the closing spring 11, whereupon preinjection commences. During this first stage of the opening stroke of the valve needle 2, the cross sectional throttling area at the injection orifice 4 is always smaller than the cross sectional area of the throttle passage 18, whereby the valve needle 2 is automatically caused to open further.

During this further opening, the upstream end of valve needle 2 penetrates through a central opening at the upstream end of nozzle head 1 and causes spring seat disc 12 to abut against a pin 21 being a downstream extension of the movable valve member 22 and thereby lifts the valve member 22 from its seat 23a. This opens a fiowpath for the major amounts of fuel via duct 17 to pressure chamber 5 from where the main fuel injection can now begin.

The small amountsof fuel penetrating into central bore 13 housing spring 11, due to leakage along valve needle 2 and pin 21, are led off via channel 23 to a fuel return pipe 23a.

What is claimed is:

1. In a fuel nozzle for an internal combustion engine, which nozzle comprises a valve needle for controlling the flow of fuel via a throttle passage to pressure chamber means for a preliminary injection out of the mouth of the nozzle and for controlling the flow of fuel via duct means to said pressure chamber means for a main injection out of the mouth of the nozzle, during the opening stroke of the valve needle,

the improvement comprising a valve means closed during rest position which valve means is mounted in said duct means and associated with said needle to be opened by said needle during the opening stroke of the latter; the free cross-sectional area of the nozzle mouth being traversed by the fuel during the preliminary injection being smaller than the cross-sectional area of said throttle passage.

2. The improvement as described in claim 1, wherein the axis of said valve along which the latter opens and closes is disposed coaxially with said valve needle.

3. The improvement as described in claim 2, wherein said valve comprises a movable valve member having a pin extending in downstream direction, a spring biassing said valve member, and a spring seat disc, the distance between the downstream end of said pin and said spring seat disc being as large as the opening stroke of said valve needle during preliminary injection.

4. The improvement as described in claim 1, wherein said pressure chamber means comprise a main chamber, and an auxiliary chamber upstream of said main chamber, and said duct means comprising a first duct from said auxiliary chamber to said main chamber, said throttle passage being located in said first duct and being open at all times, and second duct means from said auxiliary chamber to said main chamber, said valve means being interposed in said second duct.

5. The improvement as described in claim 3, wherein said movable valve member is adapted for penetrating, during opening against the force of said spring, into said auxiliary pressure chamber.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2556369 *Apr 5, 1947Jun 12, 1951American Bosch CorpAccumulator type injection nozzle
US3640466 *Oct 24, 1969Feb 8, 1972Sulzer AgFuel injection system for an internal combustion piston engine
IT510841A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3967597 *Sep 23, 1974Jul 6, 1976Robert Bosch G.M.B.H.Electromagnetically actuated fuel injection valve
US4215820 *May 3, 1978Aug 5, 1980Volkswagenwerk AktiengesellschaftInjection device for an internal combustion engine
US4228960 *Aug 30, 1978Oct 21, 1980Lucas Industries LimitedLiquid fuel injectors
US4250857 *Sep 13, 1978Feb 17, 1981The Bendix CorporationFuel injector for producing shaped injection pulses
US4461427 *Feb 11, 1982Jul 24, 1984Robert Bosch GmbhFuel injection nozzle
US4566635 *Apr 13, 1984Jan 28, 1986Robert Bosch GmbhFuel injection nozzle for internal combustion engines
US5619969 *Nov 28, 1995Apr 15, 1997Cummins Engine Company, Inc.Fuel injection rate shaping control system
US5647536 *Jan 23, 1995Jul 15, 1997Cummins Engine Company, Inc.Injection rate shaping nozzle assembly for a fuel injector
US5765755 *Jan 23, 1997Jun 16, 1998Cummins Engine Company, Inc.Injection rate shaping nozzle assembly for a fuel injector
US5769319 *Mar 14, 1997Jun 23, 1998Cummins Engine Company, Inc.Injection rate shaping nozzle assembly for a fuel injector
US5826793 *Oct 30, 1996Oct 27, 1998Lucas Industries, PlcTwo rate fuel injector
US6360727Mar 14, 2000Mar 26, 2002Alfred J. BuescherReduce initial feed rate injector with fuel storage chamber
US7334741Jan 28, 2005Feb 26, 2008Cummins Inc.Fuel injector with injection rate control
US7475674Jun 29, 2007Jan 13, 2009Siemens AktiengesellschaftLeakage connection for a fuel injector
US7475829Jul 19, 2004Jan 13, 2009Siemens AktiengesellschaftNozzle clamping nut for injection valves and method for producing said nozzle clamping nut
CN100445549CJan 28, 2006Dec 24, 2008卡明斯公司Fuel injector with injection rate control
EP1686257A2Jan 25, 2006Aug 2, 2006Cummins Inc.Fuel injector with injection rate control
Classifications
U.S. Classification239/533.5
International ClassificationF02M45/00, F02M45/08
Cooperative ClassificationF02M45/08
European ClassificationF02M45/08