DESCRIPTION

TECHNICAL FIELDS

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

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

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.

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.

SUMMARY OF THE INVENTION

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.

BRIEF DESCRIPTION OF THE DRAWINGS

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.

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

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

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.

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:

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) which can move up and down in axial direction, at least one group of fuel injection outlets (601) in said nozzle body, at least one spring (15) which urges 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 at least one of two pressured fuel reservoirs (10, 12), a pressure control chamber (581) which can press and release the said composite needle valve (I), wherein said composite needle valve contains a one way check valve (4).

A fuel injector of STATEMENT A, comprising:

(i) a nozzle body (6) comprising passages (603, 562, 602) for fuels, an inner cylindrical bore for receiving a composite needle valve (I) which can move up and down in axial direction, at least one group of fuel injection outlets (601) in said nozzle body, at least one spring (15) which urges said composite needle valve (I) into a biased seating position to block fuels, and a valve block (8) to hold control valves (9, 13) and having fuel inlets connected to at least one of two pressured fuel reservoirs (10, 12), a pressure control chamber (581) which can press and release the said composite needle valve (I) through connecting to fuel reservoirs (12, 14) with different pressures, and

(ii) said composite needle valve is composing of inner fuel channels (501, 502, 351) connected to independently controlled fuel reservoir (10), an 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 needle tip (1) which has fuel outlets(lOl), has an opening position which is moving up toward 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.

A fuel injector of STATEMENT A, wherein it is comprising at least two control valves (9, 13) to block or connect at least one type of fuel from high pressure fuel reservoirs (10, 12) to low pressure fuel reservoir (14) to produce the lifting and closing forces on said composite needle valve (I) through generating pressure differences in pressure control chamber (581).

A fuel injector of STATEMENT A, wherein it is comprising 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 higher pressure reservoir (10) can be mixed with one fuel stream from lower pressure reservoir (12) on demand within the nozzle through activating said one way valve (4). A fuel injector of STATEMENT A, wherein the said composite needle valve (I) is made by press fitting two separate components (5, 1) together. Welding can be applied to the contact lines between the two separate components to ensure integrity.

A fuel injector of STATEMENT A, wherein the said composite needle valve has needle guide (561) which is in touch with nozzle boy (6) inner surface, a needle tip bearing a sealing arc (103), and another tip section (102) which is substantially close but not in touch with nozzle inner surface at seating position.

A fuel injector of STATEMENT A, wherein it contains a one-way check valve (11) to block fuel within nozzle from flowing into pressure reservoir (12).

STATEMENT B:

A fuel injection method, wherein it is composing steps to activate 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 higher pressure reservoir (10) can be mixed with one fuel stream from lower pressure reservoir (12) on demand through activating said one-way check valve (4).

A fuel injection method of STATEMENT B, wherein two streams of different fuels through two separate fuel channels (502, 603) can be independently controlled by control valves (9, 13) but mixed within nozzle tip on demand right before being injected together by lifting the said composite needle valve (I) and through fuel outlets (101, 601), wherein, it has means to inject different fuels collectively with different fuel ratios on demand.

A fuel injection method of STATEMENT B, wherein it has steps of mixing two fuel streams with pressure difference less than 200 bar.

A fuel injection method of STATEMENT B, wherein it has steps of mixing two fuel streams of different chemical reactivity, with the ratio of less reactive fuel being less than 10%.

An internal combustion engine using at least one said fuel injector of STATEMENT A, which can 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. An internal combustion engine using at least one said fuel injection method of STATEMENT B, which can 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.

A combustion method, using at least one of the fuel injection methods discussed above, wherein it has 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.

A combustion method, 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 nozzle to tailor fuel chemical or thermal-physical properties based on different needs under different operating parameters, such as engine loads and speeds.

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.