FUEL INJECTION VALVE FOR DEMAND-CONTROLLED MULTI-Fuel INJECTION

Description

TECHNICAL FIELDS

[0001] This invention is related to a fuel injector, fuel injection method, and an internal combustion engine. Specifically, this invention disclosed a fuel injector which can collectively inject two types of fuels differentiated by at least one parameter of pressure, molecular structure or thermodynamic phases, thus has the capability to tailor fuel properties on demand, and an engine using at least one such fuel injector, which can be a spark-ignition engine or a compression-ignition engine.BACKGROUND OF THE INVENTION

[0002] This application claims the priority of US Provisional Application 62651590, filed on April 2, 2018.

[0003] Description of the Related Art - Progress has been made in recent years for advanced combustion modes, such as Homogeneous -Charge Compression-Ignition (HCCI) combustion, reactivity controlled compression ignition (RCCI) and Premixed Charge Compression Ignition (PCCI). However, many issues remain to be solved to control the ignition timing, the duration of combustion, the rate of combustion for various load and speed conditions. It is desirable to have a fuel injector which can directly inject two fuels differentiated by at least one parameter of injection pressure, molecular structure, and thermodynamics phases. Further, it is desirable to inject two types of fuels to tailor fuel properties on demand at different injection timings under different engine load and speed conditions.

[0004] However, even though many inventions have been disclosed for dual fuel injectors and injectors with variable orifices, issues related to manufacture complexity and fuel leaking have prevented many inventions from being mass production viable. Furthermore, few of previous disclosed arts can offer the injection capability of selectively and collectively direct inject different fuels without interfering with each other between the operations of injecting different fuels. Thus, previous arts demands significant control complexity, especially for synchronizing the dual needle operations normally used for dual fuel injections.

[0005] WO 2015 / 149039 A2 describes a variable orifice fuel injector having an inward opening needle valve and an outward opening needle valve and having means to directly inject two types of fuels independently and collectively. Both needle valves are fully contained in a nozzle body, with a coaxial smaller needle valve at least partially being contained in a larger needle valve.SUMMARY OF THE INVENTION

[0006] It is our goals of this invention to at least solve some of the major issues facing previous arts. More specifically, this invention offers a novel composite needle valve design which can operate both selectively and collectively to give the freedom to inject either a single fuel, either one fuel of two supplied fuels, or a combination of two supplied fuels, on demand to tailor fuel properties based on engine operation conditions and the need for optimizing combustion.

[0007] The invention is set out in the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG 1 is a fragmentary sectional view of a first exemplary embodiment of an injector of the invention with only key components marked; FIG 2 is the same as FIG 1 except with detailed notations for key components, key fuel passages, key surfaces, and key pressure control chambers marked. FIG 3 is an exemplary embodiment of the composite needle valve; FIG 4 is the enlarged sectional view of the tip of the composite needle valve.

[0009] Except specifically specified, in all the figures: I - composite needle valve; 1 - tip of the composite needle valve I; 101-outlets of I, 102, 103 - tip surface sections of I; 2 - spring within I; 3 - T component; 4 - one way check valve; 5 - top section of needle valve I; 501, 502, 351 - fuel passages within needle valve; 503 - valve seat for one way check valve; 6 - nozzle body; 601 - fuel outlets; 602, 603, 562 - fuel passages; 604 - inner nozzle surface close to nozzle tip; 7 - tighten nut; 8 - valve block which holds valves and fuel passages, 801 -high pressure fuel passage to control valve 9, 802 - fuel passage to venting valve 13, 803 - high pressure passage to control valve 11; 804 - high pressure fuel passage to pressure control chamber 581; 9 - flow control valve; 10 - high pressure fuel reservoir; 11 - one way check valve, to block fuel from flowing into 12 from within nozzle; 12 - high pressure fuel reservoir; 13 - pressure release control valve; 10 and 12 can be one such as common rail holding one type of fuel, or two common rails for different fuels or for one fuel with different pressures; 14 - low pressure fuel reservoir or fuel sink; al - half multiple jet spray angle for fuel injection outlets 601; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A first embodiment was shown in FIG 1 to FIG 4. FIG 1 shows a state of the needle valve at seating position.

[0011] We have illustrated one embodiment here. For those skilled in the art, it is easy to give alternatives based on the same operation mechanism. The embodiment illustrated here should be considered as an example without limiting the scope of the invention.

[0012] The scope of the invention being solely limited by the following claims.

[0013] Other embodiments with the same key characteristics are considered under the scope of this invention. For example, the first fuel and second fuel are the same fuel, thus the injector becomes a single fuel injector. Following features are considered as the key characteristics of the invention.STATEMENT A:

[0014] A fuel injector comprising the features of the attached claim 1.

[0015] The word 'fuel' in this application should be interpreted as a general media and an exemplary description. In this sense, at least one 'fuel' could be water, supercritical liquids, or a gas media, etc.

Claims

1. A fuel injector comprising: a nozzle body (6) comprising passages (603, 562, 602) for fuels, an inner cylindrical bore for receiving a composite needle valve (I) configured to move up and down in an axial direction, at least one group of fuel injection outlets (601) in said nozzle body (6), at least one spring (15) configured to urge said composite needle valve (I) into a biased seating position to block fuels, and a valve block (8) holding control valves (9, 13) and having fuel inlets connected to a first and second pressurised fuel reservoir (10, 12), a pressure control chamber (581) configured to press and release the said composite needle valve (I), wherein said composite needle valve contains a one way check valve (4), wherein the said composite needle valve (I) is made by press fitting two separate components (5, 1) together; and wherein the fuel injector further comprises at least two independent control valves (9, 13) to block or connect two types of fuels from high pressure fuel reservoirs (10, 12) with different pressures, wherein one fuel stream from a higher pressure reservoir (10) can be mixed with one fuel stream from a lower pressure reservoir (12) on demand within the nozzle body (6) through activating said one way check valve (4).

2. The fuel injector of claim 1, wherein: the pressure control chamber (581) is configured to press and release the said composite needle valve (I) through connecting to second and third fuel reservoirs (12, 14) with different pressures; and wherein said composite needle valve comprises inner fuel channels (501, 502, 351) connected to an independently controlled fuel reservoir (10), a one way check valve (4) supported by a T shape component (3) and a spring (2) which urges the said check valve (4) against its seat (503), capped by a needle tip (1) which has fuel outlets (101), the fuel injector having an opening position in which the composite needle valve is moved up toward a nozzle large end to inject fuel from at least one pressurized fuel reservoir through fuel injection outlets (101, 601), and a seating position to block fuel flow.

3. The fuel injector of claim 1, further comprising at least two control valves (9, 13) to block or connect at least one type of fuel from the first and second pressurised fuel reservoirs (10, 12) to at least one low pressure fuel reservoir (14) to produce the lifting and closing forces on said composite needle valve (I) by generating pressure differences in pressure control chamber (581).

4. The fuel injector of claim 1, wherein the said composite needle valve has a needle guide (561) which touches the nozzle body (6) inner surface, a needle tip bearing a sealing arc (103), and another tip section (102) which is substantially close but does not touch the nozzle inner surface at the seating position.

5. The fuel injector of claim 1, wherein the one way check valve (4) is a first one way check valve; and wherein the fuel injector further comprises a second one way check valve (11) to block the fuel within the nozzle from back flowing into the second pressurised reservoir (12).

6. A fuel injection method using the fuel injector according to any preceding claim, the method comprising the steps of activating at least two independent control valves (9, 13) to block or connect to two types of fuels from the first and second pressurised fuel reservoirs (10, 12) with different pressures, wherein one fuel stream from the first higher pressure reservoir (10) can be mixed with one fuel stream from the second lower pressure reservoir (12) on demand through activating the one way check valve (4).

7. The fuel injection method of claim 6, wherein the two streams of different fuels pass through two separate fuel channels (502, 603) and are configured to be independently controlled by the control valves (9, 13) but mixed within the nozzle tip on demand right before being injected together by lifting a composite needle valve (I) and through fuel outlets (101, 601), wherein, the method is configured to inject different fuels collectively with different ratios on demand.

8. The fuel injection method of claim 6, further comprising the steps of mixing the two fuel streams with a pressure difference of less than 200 bar.

9. The fuel injection method of claim 6, further comprising the steps of mixing the two fuel streams of different chemical reactivity, with the weight ratio of more reactive fuel being less than 10%.

10. An internal combustion engine using at least one said fuel injector of claim 1, configured to be a spark-ignition engine or a compression-ignition engine, wherein it has means to inject dual fuels with different ratios to tailor fuel properties on demand based on engine loads and speeds.

11. An internal combustion engine using at least one of the fuel injection methods of claims 6 to 9 configured to be a spark-ignition engine or a compression-ignition engine, the internal combustion engine comprising a means to inject dual fuels with different ratios to tailor fuel properties on demand based on engine loads and speeds.

12. A combustion method, using at least one of the fuel injection methods of claims 6, 7, 8, 9, comprising a means to optimize combustion under different operating conditions, through tailoring fuel chemical or thermal-physical properties on demand based on different needs under different operating parameters, such as engine loads and speeds.

13. The combustion method of 12, wherein one fuel stream is of diesel like fuel with higher chemical reactivity, one stream is with lower chemical reactivity such as gasoline, ethanol, methanol, methane, naphtha, water, wherein it has means to optimize combustion under different operating conditions, through blending the two streams on-demand within a nozzle to tailor fuel chemical or thermal-physical properties based on different needs under different operating parameters, such as engine loads and speeds.