KR20050002880A - Fuel injector for an internal combustion engine - Google Patents

Abstract

A fuel injector for vaporizing a liquid fuel for use in an internal combustion engine. The fuel injector includes at least one capillary flow passage (12) , the at least one capillary flow passage (12) having an inlet end (14) and an outlet end (16), the capillary flow passage comprises a channel formed within a monolithic body produced from a material selected from the group consisting of ceramics, polymers, metals and composites thereof or a multi-layer ceramic body, a fluid control valve (18) for placing the inlet end of the at least one capillary flow passage (12) in fluid communication with the liquid fuel source and introducing the liquid fuel in a substantially liquid state, a heat source (20) arranged along the at least one capillary flow passage, the heat source (20) operable to heat the liquid fuel in the at least one capillary flow passage (12) to a level sufficient to change at least a portion thereof from the liquid state to a vapor state and deliver a stream of substantially vaporized fuel from the outlet end of the at least one capillary flow passage.

Description

Fuel injector for an internal combustion engine

Various systems have been devised to supply fine liquid fuel droplets and air to the internal combustion engine. These systems use a carburetor or fuel injector (s) (indirect injection) to feed fuel directly into the combustion chamber (direct injection) or to feed the mixture through the intake manifold into the combustion chamber. In current systems, the fuel-air mixture is produced by atomizing liquid fuel and feeding it as air droplets into the air stream.

In conventional flame ignition engines employing port-fuel injection, the injected fuel is vaporized by directing liquid fuel droplets to hot components in the intake port or manifold under normal operating conditions. The liquid fuel is deposited on the surface of the hot component and then vaporized. The mixture of vaporized fuel and intake air is then aspirated into the cylinder by the pressure difference created as the intake valve opens and the piston moves toward the bottom dead center. In order to ensure a degree of control compatible with modern engines, this vaporization technique is typically optimized to occur in less than one engine cycle.

Under modern engine operating conditions, the temperature of the intake components is sufficient to rapidly vaporize the colliding liquid fuel droplets. However, under conditions such as cold start and warm up, fuel does not vaporize through collisions on relatively low temperature engine parts. Instead, engine operation under these conditions is ensured by supplying excess fuel such that sufficient portion evaporates through heat and mass transfer as it progresses through the air before it hits the cold intake components. The evaporation rate through this mechanism is a function of fuel properties, temperature, pressure, relative droplet and air velocity, and droplet diameter. Of course, this approach fails in cold start in extreme atmospheres where fuel volatility is insufficient to produce an ignitable concentration of vapor with air.

To achieve chemically complete combustion, the fuel-air mixture must be vaporized into a stoichiometric gas-phase mixture. The theoretical combustible mixture contains the exact amount of air (oxygen) and fuel required for complete combustion. For gasoline, this air-fuel ratio is about 14.7: 1 weight ratio. Fuel-air mixtures that are not completely vaporized or are not theoretical will result in incomplete combustion and reduced thermal efficiency. The products of the anomalous combustion process are water (H ₂ O) and carbon dioxide (CO ₂ ). If combustion is incomplete, some of the carbon is not completely oxidized and produces carbon monoxide (CO) and unburned hydrocarbons (HC).

The policy to reduce air pollution has resulted in attempts to compensate for combustion inefficiencies with various fuel system and engine modifications. As is evident in the prior art for fuel preparation and supply systems, a number of efforts have been made to provide sufficient heat to reduce liquid fuel droplet size, increase system turbulence, and vaporize fuel to allow more complete combustion. Was performed.

However, inefficient fuel preparation at low engine temperatures generates higher emissions, leaving the problem of requiring post-treatment and complex control schemes. These control schemes include exhaust gas recirculation, variable valve timing, ignition timing delays, reduced compression ratios, the use of catalytic converters and air injection to oxidize unburned hydrocarbons and produce exothermic reactions that benefit from catalytic converter light-off. It may include.

The excess fuel supply of the engine during cold start and warm up is an important cause of unburned hydrocarbon exhaust in conventional engines. In addition, the fact that the catalytic converter is low temperature during this operating period and therefore does not reduce the significant amount of unburned hydrocarbons passing through the engine exhaust is a serious problem. As a result, unburned hydrocarbons of high engine-out concentration pass through the catalytic converter without substantially reacting and exit from the exhaust pipe. It is estimated that around 80% of the total hydrocarbon emissions produced by typical modern passenger cars occur during cold start-up and warm-up periods when the engine is oversupply and the catalytic converter is substantially inactive.

In view of the relatively large fraction of unburned hydrocarbons emitted during start-up, this aspect of car engine operation has been the focus of significant technical development efforts. Moreover, these development efforts will continue to focus, as more stringent exhaust standards are enacted and consumers are still sensitive to price and performance. This effort to reduce starting emissions from conventional engines is generally classified into two categories: 1) reduction of warm-up time for three-way catalyst systems, and 2) improvement of techniques for fuel vaporization. Efforts to reduce the warm-up time for conventional three-way catalysts include delays in ignition timing to raise the exhaust temperature, premature opening of the exhaust valve, electrical heating of the catalyst, burners or flames heating the catalyst, and catalysis of the catalyst. By heating. Overall, these efforts are expensive and fail to cope with HC emissions during and immediately after cold start.

Various techniques have been proposed to address the issue of fuel vaporization. US patents suggesting fuel vaporization techniques are described in US Pat. No. 5,195,477 to Hudson, Jr. et al., US Pat. No. 5,331,937 to Clarke, Asmus. U.S. Patent 4,88,032, Lewis et al. U.S. Patent 4,955,351, Oza U.S. Patent 4,458,655, Cooke U.S. Patent 6,189,518, Hunt US Patent No. 5,482,023 to Hunt, US Patent No. 6,109,247 to Hunt, US Patent No. 6,067,970 to Awarzamani, and US Patent No. 5,947,091 to Krohn et al. US Pat. No. 5,758, 826 to Nines, US Pat. No. 5,836,289 to Thring, US Pat. No. 5,813,388 to Cikanek, Jr., and the like.

Other proposed fuel supply devices include US Pat. No. 3,716,416, which discloses a fuel metering device for use in a fuel cell system. The fuel cell system is configured to self regulate to a predetermined level to generate power. The proposed fuel metering system includes a capillary flow control device for throttling fuel flow in response to the power output of the fuel cell, rather than providing improved fuel preparation for subsequent combustion. Instead, the fuel is intended to be supplied to the fuel modifier for conversion to H ₂ and then to the fuel cell. In a preferred embodiment, the capillary tube is made of metal and the capillary tube itself is used as a resistor in electrical contact with the voltage output of the fuel cell. Since the flow resistance of the vapor is greater than the liquid, the flow is throttled as the power output increases. Fuels proposed for use include any fluid that readily converts from the liquid phase to the gas phase by applying heat and freely flows through the capillary. Vaporization turns out to be achieved in such a way that a vapor lock occurs in the automobile engine.

U.S. Patent No. 6,276,347 proposes a supercritical or near-supercritical nebulizer and method for achieving atomization or vaporization of liquids. The supercritical nebulizer of US Pat. No. 6,276,347 is described as enabling the use of heavy oil to ignite a small, light weight, low compression ratio spark ignition piston engine that typically burns gasoline. The nebulizer produces a spray of fine droplets from the liquid or liquid fuel by moving the fuel towards their supercritical temperature and releasing the fuel to the lower pressure zone of the gas stabilization field in the phase diagram associated with the fuel, thereby atomizing the fuel. It is configured to generate fire or vaporization. Practicality is disclosed for applications such as combustion engines, scientific equipment, chemical treatment, waste disposal control, cleaning, etching, insect control, surface modification, humidification and vaporization.

In order to minimize degradation, US Pat. No. 6,276,347 limits the maintenance of fuel below the supercritical temperature before passing through the distal end of the limiter for atomization. In certain applications, heating only the tip of the restrictor is required to minimize the possibility of chemical reactions or precipitation. This has been described as reducing the problems associated with impurities, reactants or materials in the fuel stream that otherwise tend to drain out of solution and block lines and filters. Operation at supercritical or near supercritical pressure suggests that the fuel supply system operates in the range of 21.1 to 56.2 Kg / cm 2 (300 to 800 psi). The use of supercritical pressures and temperatures can reduce the blockage of the nebulizer, but requires the use of relatively more expensive fuel pumps capable of operating at these elevated pressures, as well as fuel lines, fittings, and the like. It turns out.

The present invention relates to fuel supply in an internal combustion engine. More specifically, the method and apparatus according to the present invention is to provide at least one heated capillary flow passage for vaporizing fuel supplied to the internal combustion engine.

1 is a partial cross-sectional view of a modified fuel injector including capillary flow passages in accordance with a preferred configuration.

2 is a side view of an embodiment of a fuel injector according to another preferred form;

FIG. 2A is an isometric view of the outlet of the capillary of the embodiment shown in FIG. 2. FIG.

3 is a side view of another embodiment of a fuel injector according to another preferred form;

3A is an isometric view of another outlet design of the capillary of the embodiment shown in FIG. 3.

4 is a side view of another embodiment of a fuel injector of the preferred form;

4A is an isometric view of another outlet design of the capillary of the embodiment shown in FIG. 4.

5 is a schematic diagram of another embodiment of a fuel injector according to a preferred form;

6 is a side view of another embodiment of a fuel injector of the preferred form;

7 is a sectional view of another embodiment of a fuel injector according to another preferred form.

8 is a side view of another embodiment employing a dual injector according to another preferred form.

9 is a side view of another embodiment of a fuel injector of the preferred form shown in partial cross-sectional view.

9A is an enlarged view of the same part of the embodiment shown in FIG.

10 is a side view of another embodiment of a fuel injector according to the preferred form shown in partial cross-sectional view.

10A is an enlarged view of the same part of the embodiment shown in FIG.

11 is a side view of another preferred form of a fuel injector according to the preferred form;

11A is an isometric view of another outlet design of the capillary of the embodiment shown in FIG. 11.

12 is a side view of another embodiment of a fuel injector having capillary passages heated by recycled exhaust gas.

13 is a schematic diagram of a fuel supply and control system in accordance with a preferred form;

Fig. 14 is a chart for explaining engine parameters during the first 20 seconds of starting of the engine using the fuel supply device of the present invention.

15 is a chart for explaining a comparison between a conventional port fuel injector and engine exhaust from the fuel supply device of the present invention.

FIG. 16 is a graph of gasoline mass flow as a function of time showing the benefits to operation achieved through the use of the oxidative cleaning method of the present invention. FIG.

17 is a graph of fuel flow rate versus time for commercial gasoline.

18 is a graph of fuel flow versus time comparing various gasolines.

19 is a graph of fuel flow rate versus time comparing No. 2 diesel fuel and jet fuel.

20 is a graph of fuel flow rate versus time in an unadded diesel fuel showing the effect of oxidative cleaning.

FIG. 21 is a graph of fuel flow versus time comparing diesel fuel with an antifouling additive to an unadded diesel fuel. FIG.

In one aspect, the invention is a fuel injector for vaporizing liquid fuel for use in an internal combustion engine,

(a) at least one capillary flow passage having an inlet end and an outlet end;

(b) a fluid control valve for placing the inlet end of said at least one capillary flow passage in fluid communication with a liquid fuel source and for introducing liquid fuel into a substantially liquid state; And

(c) is arranged along the at least one capillary flow passage and heats the liquid fuel in the at least one capillary flow passage to a level sufficient to change at least a portion thereof from the liquid state to the vapor state and the at least one capillary flow passage A fuel injector comprising a heat source operable to supply a stream of substantially vaporized fuel from an outlet end of the.

In another aspect, the present invention provides a fuel system for use in an internal combustion engine.

(a) (i) at least one capillary flow passage having an inlet end and an outlet end; (Ii) a fluid control valve for placing the inlet end of said at least one capillary flow passage in fluid communication with a liquid fuel source and for introducing substantially liquid liquid fuel; And (iii) arranged along the at least one capillary flow passage, heating the liquid fuel in the at least one capillary flow passage to a level sufficient to change at least a portion thereof from the liquid state to the vapor state and the at least one capillary flow passage. A plurality of fuel injectors each including a heat source operable to supply a stream of substantially vaporized fuel from an outlet end of the passageway;

(b) a liquid fuel supply system in fluid communication with the plurality of fuel injectors; And

(c) a fuel system comprising a controller for controlling the supply of fuel to the plurality of fuel injectors.

In another aspect, the present invention provides a method of supplying fuel to an internal combustion engine,

(a) supplying liquid fuel to at least one capillary flow passage of the fuel injector;

(b) heating the liquid fuel in the at least one capillary flow passage to allow a stream of substantially vaporized fuel to pass through the outlet of the at least one capillary flow passage;

(c) supplying vaporized fuel to a combustion chamber of the internal combustion engine,

The capillary flow passages are directed to a method comprising channels formed in a monolithic body or multilayer ceramic body made of a material selected from the group consisting of ceramics, polymers, metals and composites thereof.

The present invention vaporizes while requiring minimum power and warm up time without the need for a high pressure fuel supply system, which may be used in a number of structures including conventional port fuel injection, hybrid electric, gasoline direct injection, and alcohol fueled engines. It provides a fuel injector and a supply system capable of supplying the fuel.

Reference will now be made in detail to the preferred embodiments of the present invention, provided by way of example only, and with reference to the accompanying drawings.

Reference is now made to the embodiment shown in FIGS. 1 to 21 where like reference numerals are used to denote like parts throughout.

The present invention provides fuel preparation and supply useful for cold start, warm up and normal operation of an internal combustion engine. The fuel system includes a fuel injector having a capillary flow passage capable of heating liquid fuel such that substantially vaporized fuel is supplied into the engine cylinder. Substantially vaporized fuel may be burned with reduced emissions compared to conventional fuel injector systems. Moreover, the fuel supply system of the present invention requires low power and has a shorter warm up time than other vaporization techniques.

In general, gasoline does not vaporize immediately at low temperatures. During cold start and warm up periods, relatively little vaporization of liquid fuel occurs. As such, there is a need to provide excess liquid fuel to each cylinder of the engine to achieve a combustible air / fuel mixture. Upon ignition of fuel vapor produced from excess liquid fuel, the combustion gases discharged from the cylinder include unburned fuel and undesirable gaseous emissions. However, when the normal operating temperature is reached, less fuel is required to achieve an air / fuel mixture that can be vaporized immediately and burned immediately. Advantageously, when the normal operating temperature is reached, the air / fuel mixture can be controlled at theoretical or near theoretical ratios to reduce emissions of unburned hydrocarbons and carbon monoxide. Additionally, if the fuel supply is controlled at theoretical or near theoretical ratios, only the required air is available in the exhaust stream for the simultaneous oxidation of unburned hydrocarbons and carbon monoxide and the reduction of nitrogen oxides across the three-way catalyst (TWC).

The systems and methods of the present invention inject substantially vaporized fuel directly into the intake flow passages or into the engine cylinders, eliminating the need for excess fuel during engine start-up and warm-up periods. It is preferred that the fuel is supplied to the engine in theory or air, or a fuel-lean mixture with air and diluent so that substantially all of the fuel is burned during the cold start and warm up periods.

In conventional port fuel injection, excess fuel supply has been required to ensure a firm and fast engine start. Under fuel-rich conditions, the exhaust stream reaching the three-way catalyst does not contain enough air to oxidize excess fuel and unburned hydrocarbons as the catalyst warms up. One approach to address this problem is to use an air pump to supply additional air to the exhaust stream upstream of the catalytic converter. The aim is to produce a theoretical or sparse fuel lean exhaust stream that can react on the catalyst surface once the catalyst reaches its activation temperature. In contrast, the systems and methods of the present invention allow the engine to operate in theoretical or even fuel lean conditions during cold start and warm up periods, eliminating both the need for excess fuel supply and the need for additional exhaust air pumps. This reduces the cost and complexity of the exhaust aftertreatment system.

As mentioned above, during the cold start-up and warm-up periods, the three-way catalyst is initially cold and it is not possible to reduce the significant amount of unburned hydrocarbons passing through the catalyst. Many efforts have been devoted to reducing the warm up time of the three-way catalyst to convert more of the unburned hydrocarbons released during the cold start and warm up periods. One such concept is to intentionally operate the engine in a very fuel surplus during cold start and warm up periods. Using an exhaust air pump to supply air to this excess fuel exhaust stream, a combustible mixture can be produced which is combusted by a predetermined ignition source upstream or within the catalytic converter or by automatic ignition. The exotherm generated by this oxidation process heats the exhaust gas considerably and heat is mostly transferred to the catalytic converter as the exhaust passes through the catalyst. Using the system and method of the present invention, the engine can be controlled to alternately operate the cylinders in fuel surplus and fuel lean to achieve the same effect without the need for an air pump. For example, in a four-cylinder engine, two cylinders may operate in fuel surplus during cold start and warm up periods to produce unburned hydrocarbons in the exhaust. The two remaining cylinders can operate in a fuel lean state during cold start and warm up to provide oxygen to the exhaust stream.

The systems and methods of the present invention may also be used in gasoline direct injection engines (GDI). In a GDI engine, fuel is injected directly into the cylinder as a finely atomized spray that evaporates and mixes with air to form a premixed charge of air and evaporative fuel prior to ignition. Modern GDI engines require high fuel pressure to atomize the fuel spray. The GDI engine operates with stratified charge at partial load to reduce the pumping losses inherent in conventional direct injection engines. Stratified, spark ignition engines have the potential to burn lean mixtures for improved fuel consumption and reduced emissions. Preferably, the entire lean mixture is formed in the combustion chamber, but in the vicinity of the spark plug upon ignition is controlled in a theoretical or slightly fuel surplus state. Thus, the theoretical state portion is easily ignited, which then ignites the remaining lean mixture. Although pumping losses can be reduced, the operating windows currently available for stratified charging are limited to low engine speeds and relatively light engine loads. Limiting factors include insufficient time for mixing and vaporization at high engine speeds, and insufficient mixing or poor air utilization at high loads. By providing vaporized fuel, the systems and methods of the present invention can extend the operating window for stratified filling operations, thereby solving the problems associated with insufficient time for vaporization and mixing. Advantageously, unlike conventional GDI fuel systems, the fuel pressure employed in the practice of the present invention can be lowered, reducing the overall cost and complexity of the fuel system.

The present invention provides a fuel supply apparatus for an internal combustion engine comprising a pressurized liquid fuel source for supplying liquid fuel under pressure, at least one capillary flow passage connected to the liquid fuel source, and a heat source arranged along the at least one capillary flow passage. . The heat source is operable to heat the liquid fuel in the at least one capillary flow passage to sufficiently supply a stream of substantially vaporized fuel. The fuel supply device is preferably operated to supply a stream of vaporized fuel to one or more combustion chambers of the internal combustion engine during start up, warm up and other operating conditions of the internal combustion engine. If desired, at least one capillary flow passage may be used to supply liquid fuel to the engine under normal operating conditions.

The invention also provides a step of supplying pressurized liquid fuel to at least one capillary flow passage and a sufficient stream of vaporized fuel to be supplied to at least one combustion chamber of the internal combustion engine during start up, warm up and other operating conditions of the internal combustion engine. And heating the pressurized liquid fuel in the at least one capillary flow passage.

The fuel supply system according to the invention comprises at least one capillary-size flow passage through which pressurized fuel flows before being injected into the engine for combustion. The capillary-size flow passage may have a hydraulic diameter which is preferably less than 2 mm, more preferably less than 1 mm, most preferably less than 0.5 mm. The hydraulic diameter is used to calculate the fluid flow through the fluid carrying element. The hydraulic radius is defined as the flow region of the fluid conveying element divided by the perimeter of the solid boundary in contact with the fluid (generally referred to as the "wetted" peripheral length). In the case of fluid transport elements of circular cross section, the hydraulic radius when the element is fully flow ^{(πD 2/4) / πD} = D / 4. For flow of fluid in non-circular fluid conveying elements, hydraulic diameters are used. From the definition of the hydraulic radius, the diameter of the fluid conveying element having a circular cross section is four times its hydraulic radius. Therefore, the hydraulic diameter is defined as four times the hydraulic radius.

Heat is applied along the capillary passageway so that at least a portion of the liquid fuel entering the flow passage is converted to steam as it moves along the passageway. The fuel exits the capillary passageway as a vapor that optionally contains a small percentage of the heated liquid fuel that is not vaporized. Substantially vaporized means that at least 50% of the volume of the liquid fuel is vaporized by the heat source, more preferably at least 70%, most preferably at least 80% of the liquid fuel is vaporized. Although it may be difficult to achieve 100% vaporization due to the complex physical effects that occur, complete vaporization may nevertheless be desirable. These complex physical effects include deviations in the boiling point of fuel because the boiling point is pressure dependent and the pressure can be varied in the capillary flow passages. Thus, even though most of the fuel is considered to have reached the boiling point during heating in the capillary flow passage, it is sufficient to allow some of the liquid fuel to fully vaporize by passing through the outlet of the capillary flow passage with the vaporized liquid. It may not be heated.

The capillary-sized fluid passage is preferably formed in a capillary body, such as a single or multilayer metal, ceramic or glass body. The passageway has an enclosed volume opening to the inlet and outlet, either or both of which may be open to the outside of the capillary body or may be connected to another passageway or fitting in the same body or other body. The heater may be formed as part of a body, such as a section of stainless steel pipe, or the heater may be a wire or a separate layer of resistance heating material incorporated into or on top of the capillary body. The fluid passageway may be of any shape, including an enclosed volume opening to an inlet and an outlet through which fluid may pass. The fluid passageway may have any desired cross section with a desired cross section causing a uniform diameter. Other capillary fluid passage cross sections include non-circular shapes such as triangles, squares, rectangles, ellipses or other cross sections and the cross sections of the fluid passages need not be uniform. The fluid passage may extend straight or non-linear, and may be a single fluid passage or a multipath fluid passage. If the capillary passage is defined by a metal capillary tube, the tube may have an inner diameter of 0.01 to 3 mm, preferably 0.1 to 1 mm and most preferably 0.15 to 0.5 mm. Alternatively, the capillary passages are 8 × 10^-5To 7 mm 2, preferably 8 × 10^-3To 8 × 10^-OneMm 2, more preferably 2 × 10^-3To 2 × 10^-OneMm2 It may be defined by the cross sectional area of the passageway, which may be. Multiple or multiple combinations of single or multiple capillaries, various pressures, various capillary lengths, amount of heat applied to the capillaries, and different cross-sectional areas may be suitable for certain applications.

The liquid fuel may be supplied to the capillary flow passages at a pressure of at least 0.7 kg / cm 2 (10 psig), preferably at least 1.4 kg / cm 2 (20 psig). If the capillary flow passage is defined by the interior of a stainless steel pipe having an inner diameter of approximately 0.051 cm (0.020 in) and a length of approximately 15.2 cm (5 in), the fuel may be approximately 100 to 200 mg / s of an automobile engine cylinder of a normal size It is desirable to feed the capillary passages at a pressure of 7 kg / cm < 2 > (100 psig) to achieve the mass flow required for the theoretical state start. At least one passage to ensure a theoretical or nearly theoretical mixture of fuel and air that can be ignited and combusted within the cylinder (s) of the engine without producing undesirable high levels of unburned hydrocarbons or other emissions Provide a sufficient flow of substantially vaporized fuel. The capillary tube is also suitable for vaporizing fuel to very rapid, preferably within 2.0 seconds, more preferably within 0.5 seconds, most preferably within 0.1 seconds, where the capillary passage is advantageous in applications involving cold start of the engine. It is characterized by having a low thermal inertia so that the temperature can be reached. Low thermal inertia can also provide advantages during normal operation of the engine, such as by improving the responsiveness of the fuel supply to sudden changes in engine power requirements.

During vaporization of the liquid fuel in the heated capillary passages, a stack of carbon and / or large quantities of hydrocarbons may accumulate in the capillary walls and finally the flow of fuel that may lead to blockage of the capillary flow passages may be strictly regulated. have. The rate at which these stacks accumulate is a function of capillary wall temperature, fuel flow rate and fuel type. It is contemplated that fuel additives may be useful for reducing such laminates. However, if the blockage develops, this blockage can be resolved by oxidizing the stack.

1 shows a fuel injector 10 for vaporizing liquid fuel drawn from a liquid fuel source in accordance with the present invention. The apparatus 10 includes a capillary flow passage 12 having an inlet end 14 and an outlet end 16. Flow control valve 18 is in fluid communication with liquid fuel source F to place inlet end 14 of capillary flow passage 12 and to introduce liquid fuel in a substantially liquid state into capillary flow passage 12. Is provided.

As desired, flow control valve 18 may be actuated by solenoid 28. Solenoid 28 has a coil winding 32 connected to electrical connector 30. When coil winding 32 is excited, solenoid element 36 is pulled into the center of coil winding 32. When electricity is disconnected from the coil winding 32, the spring 38 returns the solenoid element to its original position. Pintle 40 is connected to solenoid element 36. The moment of the solenoid element 36 generated by applying electricity to the coil winding 32 causes the pintle to be pulled apart from the orifice 42 to flow fuel through the orifice 42.

The heat source 20 is arranged along the capillary flow passage 12. As most preferred, the heat source 20 is provided by forming a capillary flow passage 12 from a tube of electrically resistive material, the portion of the capillary flow passage 12 providing a connection 22, for the current source to supply current therethrough. 24 is connected to the tube to form a heater element. As can be appreciated, the heat source 20 then heats the liquid fuel in the capillary flow passage 12 to a level sufficient to change at least a portion thereof from the liquid state to the vapor state and exits the capillary flow passage 12. It is operable to supply a stream of substantially vaporized fuel from the end 16.

The device 10 also includes means for cleaning the stack formed during operation of the device 10. The stack cleaning means shown in FIG. 1 includes an oxidant control valve 26 for placing the capillary flow passage 12 in fluid communication with a flow control valve 18, a heat source 20 and a source of oxidant (C). do. As can be appreciated, the oxidant control valve can be positioned at or adjacent to both ends of the capillary flow passage 12 or configured to be in fluid communication with both ends of the capillary flow passage 12. When the oxidant control valve is positioned at or adjacent to the outlet end 16 of the capillary flow passage 12, it is in fluid communication with the outlet end 16 of the capillary flow passage 12 to place a source of oxidant (C). Function In operation, the heat source 20 is used to heat the oxidant in the capillary flow passage 12 to a level sufficient to oxidize the stack formed during heating of the liquid fuel F. In one embodiment, to switch from the fuel supply mode to the cleaning mode, the oxidant control valve 26 alternately performs the introduction of the liquid fuel F into the capillary flow passage 12 and the introduction of the peroxidant C. It is operable to enable in-situ cleaning of capillary flow passage 12 when an oxidant is introduced into at least one capillary flow passage.

One technique for oxidizing the stack includes passing air or steam through the capillary. The flow passages are preferably heated during the wash operation so that the oxidation process is initiated and positive until the stack is consumed. To improve this wash operation, the catalytic material may be employed as its part as a coating on capillary walls to reduce the temperature and / or time required to achieve the wash. For continuous operation of the fuel supply system, one or more fuel flows can be switched to another capillary flow passage when the occlusion condition is detected by the use of a sensor or the like and the oxidant flow can be initiated through the occluded capillary flow passage to be cleaned. Capillary flow passages may be used. As one example, the capillary body may include a plurality of capillary flow passages therein, and a valve device may be provided to selectively supply liquid fuel or air to each flow passage.

Alternatively, the fuel flow can be diverted from the capillary flow passage and the oxidant flow initialized at predetermined intervals. The fuel supply to the capillary flow passage can be performed by a controller. For example, the controller may activate the fuel supply for a preset time period and deactivate the fuel supply after a preset amount of time. The controller may also effect adjustment of the amount of heat supplied to the capillary flow passage and / or the pressure of the liquid fuel based on one or more sensed conditions. The conditions sensed may include fuel pressure, capillary temperature, and air fuel mixture in particular. The controller may also control multiple fuel supply devices attached to the installation. The controller may also control one or more capillary flow passages to remove obstructions or stacks therefrom. For example, cleaning of the capillary flow passage may be accomplished by applying heat to the capillary flow passage and supplying a flow of oxidant source to the capillary flow passage.

The heated capillary flow passage 12 may produce a vaporized stream of fuel that is condensed in the air to form a mixture of vaporized fuel, fuel droplets, and air, commonly referred to as an aerosol, according to the present invention. . The aerosol is less than 25 μm SMD, preferably less than 15 μm SMD as compared to a conventional automotive port fuel injector that supplies fuel spray consisting of droplets in the range of 150 to 200 μm Sauter Mean Diameter (SMD). Has an average droplet size. Thus, most of the fuel droplets produced by the heated capillary tubes according to the present invention can be carried by the air stream into the combustion chamber regardless of the flow path.

The difference between the droplet size distribution of the conventional injector and the heated capillary flow passages according to the invention is particularly important during cold start and warm up conditions. Specifically, using conventional port fuel injectors, the relatively low temperature intake manifold component requires an excess fuel supply such that a sufficient portion of the bulk fuel droplets impinging on the intake component is vaporized to produce an ignitable fuel / air mixture. Shall be. In contrast, the vaporized fuel and fine droplets produced by the fuel injectors of the present invention are essentially unaffected by the temperature of the engine parts at start-up, thus eliminating the need for excess fuel supply during engine start-up conditions. The elimination of excess fuel supply, combined with more precise control over the air-fuel ratio of the engine obtained through the use of the heated capillary injector of the present invention, results in a significantly reduced cold start compared to that produced by engines employing conventional fuel injector systems. Generate exhaust. In addition to the reduction of the excess fuel supply, it should also be noted that the heated capillary injector according to the invention enables fuel lean operation during cold start-up and warm-up, which leads to a significant reduction in the exhaust pipe exhaust during the catalytic converter warming up. do.

With continued reference to FIG. 1, the capillary flow passage 12 may comprise a heater having a metal tube, such as a stainless steel capillary tube, and a tube 20 of predetermined length through which a current passes. In a preferred embodiment, the capillary tube has an inner diameter of approximately 0.051 to 0.076 cm (0.020 to 0.030 in), a heating length of approximately 5.08 to 25.4 cm (2 to 10 in), and the fuel is less than 7.0 kg / cm 2 (100 psig), Preferably it may be fed to the tube 12 at a pressure of less than 4.9 kg / cm 2 (70 psig), more preferably less than 4.2 kg / cm 2 (60 psig), even more preferably 3.1 kg / cm 2 (45 psig). . This embodiment provides a vaporized fuel that forms a distribution of aerosol droplets that range in size from 2 to 30 μm SMD with an average droplet size of 5 to 15 μm SMD when the vaporized fuel is condensed in air at ambient temperature. It is shown to produce. The preferred size of the fuel droplet to achieve rapid and nearly complete vaporization at cold start temperatures is less than about 25 μm. This results in approximately 15.24 cm (6 in) stainless steel with a power of approximately 10.2 to 40.8 kg / sec (100 to 400 W), for example 20.4 kg / sec (200 W) corresponding to 2-3% of the energy content of the vaporized fuel. By applying it to a capillary tube. The electric power is a non-electrically conductive tube or laminate having a flow passage therein, such as forming the tube entirely with an electrically conductive material such as stainless steel, or laminating or coating the electrically resistive material to form a resistance heater on the tube or laminate. It can be applied to the capillary tube by providing a conductive material over at least a portion of the. Electrical conductors may be connected to the electrically conductive material to supply current to the heater to heat the tube along its length. An alternative for heating the tube along its length is an electrical coil located around the flow passage or another heat source positioned relative to the flow passage for heating the flow passage of any length via one or a combination of conduction, convection or radiative heat transfer. Induction heating by may include.

Preferred capillary tubes have a heating length of approximately 15.2 cm (6 in) and an inner diameter of approximately 0.051 cm (0.020 in), but other capillary shapes provide acceptable vapor quality. For example, the inner diameter can range from 0.05 to 0.08 cm (0.02 to 0.03 in) and the heating portion of the capillary tube can range from 2.5 to 25.4 cm (1 to 10 in). After cold start and warm up, it is not necessary to heat the capillary tube so that the unheated capillary tube can be used to supply the appropriate liquid fuel to the engine operating at normal temperature.

The vaporized fuel exiting the fuel capillary according to the invention can be injected into the engine intake manifold at the same location as the existing port fuel injector or at another location along the intake manifold. However, if desired, the fuel capillary can be arranged to supply the vaporized fuel directly into each cylinder of the engine. Fuel capillaries provide an advantage over systems that produce larger droplets of fuel that must be injected against the rear face of a closed intake valve during engine start up. Preferably, the outlet of the fuel capillary tube is located flush with the intake manifold wall, similar to the arrangement of outlets of conventional fuel injectors.

Approximately 20 seconds (or preferably less) after starting the engine, the power used to heat the capillary flow passage 12 is turned off and liquid injection is initiated using a conventional fuel injector for normal engine operation. . Normal engine operation may alternatively be performed by liquid fuel injection through the unheated capillary flow passage 12 by continuous injection or possibly pulsed injection.

2, a second exemplary embodiment of the present invention is shown. The fuel injector 100 has a capillary flow passage 112. The capillary flow passage 112 is heated along the heating length 20 defined by the electrical connections in a manner similar to that shown in FIG. 1. Capillary flow passage 112 has a deployable end 150 having a plurality of perforations 152 in a plate 154 that covers the flared end 150 as shown in FIG. 2A. The fuel injector 100 may include a fluid control valve, such as a solenoid valve of the type shown in FIG. 1 and described above that allows the supply of pressurized liquid fuel to the capillary flow passage 112. After the engine has sufficiently warmed up, the heating of the capillary flow passage 112 may be terminated and liquid fuel may be supplied through the capillary flow passage 112.

Referring now to FIG. 3, a third exemplary embodiment of the present invention is shown. The fuel injector 200 is shown with a capillary flow passage 212. The capillary flow passage 212 is heated along the heating length 220 defined by the electrical connections in a manner similar to that shown in FIG. 1. Capillary flow passage 212 has a flat end 250 having a plurality of perforations 252 in a plate 254 that covers flat end 250 as shown in FIG. 3A. The fuel injector 200 may include a fluid control valve, such as a solenoid valve of the type shown in FIG. 1 and described above that allows the supply of pressurized liquid fuel to the capillary flow passage 212. As described above, after the engine using the plurality of fuel injectors 200 is sufficiently warmed up, the heating of the capillary flow passage 212 may be terminated and liquid fuel may be supplied through the capillary flow passage 212. The injector 200 is preferably capable of being cleaned by the use of the oxidation techniques described above.

Referring now to FIG. 4, a fourth exemplary embodiment of the present invention is shown. A fuel injector 300 with a capillary flow passage 312 is shown. The capillary flow passage 312 is heated along the heating length 320 defined by the electrical connections in a manner similar to that shown in FIG. 1. Capillary flow passage 312 has a conical end 350 having a plurality of perforations 352 in conical plate 354 covering conical end 350 as shown in FIG. 4A. The fuel injector 300 may include a fluid control valve, such as a solenoid valve of the type shown in FIG. 1 and described above that allows the supply of pressurized liquid fuel to the capillary flow passage 312. As described above, after the engine using the plurality of fuel injectors 300 is sufficiently warmed up, the heating of the capillary flow passage 312 may be terminated and liquid fuel may be supplied through the capillary flow passage 212. Injector 300 is preferably capable of being cleaned by the use of the oxidation techniques described above.

Referring now to FIG. 5, a dual fuel injector 400 in accordance with the present invention is shown. 5 illustrates a dual function fuel injector 400, which may include a conventional type of fuel injector 460 and a heated capillary injector 410. In this embodiment, the heated capillary flow passage 412 is integrated within the fuel injector 400. About 20 seconds or less after engine start, capillary injector 410 is deactivated via solenoid-operated plunger 436 and conventional injector 460 is another solenoid-operated plunger for continuous operation of the engine. It may be activated via 470.

Another exemplary embodiment of the invention is shown in FIG. 6. As shown, the fuel injector 500 may have a heated capillary flow passage 512 and a liquid fuel injector nozzle 560. The fuel flow may be selectively directed to the nozzle 560 to provide liquid fuel by the use of a heated capillary flow passage 512 or valve arrangement 540 to provide vaporized fuel as shown in FIG. 6. Can be. Approximately 20 seconds or less after starting the engine, the fuel flow may be diverted from the capillary flow passage 512 to the liquid flow nozzle 560 by a valve device 540 for normal operation of the engine. The valve device 540 can be operated by a controller that forms part of an electronic engine control system.

Referring now to FIG. 7, another embodiment of the present invention is shown. The fuel injector 600 has a spirally heated capillary flow passage 612 wound inside the fuel injector 600 as shown in FIG. 7. In this embodiment, the capillary flow passage 612 is wound around the solenoid assembly 628 and heated along the heating length 620 defined by the electrical connections 622, 624. This embodiment is useful where space is limited and linear capillary tubes are not possible. In addition, this embodiment can be adapted for use with conventional fuel injectors (see FIG. 8) for fueling the engine during normal operating conditions.

Referring now to FIG. 8, engine intake port 700 includes a heated capillary injector 10 (type described with reference to FIG. 1) and a conventional liquid fuel injector 750. In this embodiment, fuel may be supplied to the engine by heated capillary flow passages 12 along its length 20 during cold start and warm up of the engine. After approximately the first 20 seconds or less from the start of the engine, the heated capillary injector 10 can be deactivated and the conventional fuel injector 750 is activated during normal operation of the engine.

As can be appreciated, the apparatus and system for fuel preparation and supply shown in FIGS. 1-4 and 7 may also be used in conjunction with other embodiments of the present invention. Referring again to FIG. 1, the stack cleaning means includes a fluid control valve 18, a solvent control valve 26 for placing the capillary flow passage 12 in fluid communication with the solvent, and the solvent control valve 26. Is disposed at one end of the capillary flow passage 12. In one embodiment of the apparatus employing solvent wash, solvent control valve 26 (preferably an oxidant control valve employing the oxidative wash technique described above) is used to introduce liquid fuel into capillary flow passage 12 and Operable to alternately perform introduction, allowing in situ cleaning of capillary flow passage 12 when solvent is introduced into capillary flow passage 12. Although a wide range of solvents are useful, the solvent may include liquid fuel from a liquid fuel source. In this case, no solvent control valve is required, since there is no need to alternately supply fuel and solvent, and the heat source phased out or deactivates over time during the cleaning of the capillary flow passage 12. Should be.

Another embodiment of the present invention is shown in the partial cross-sectional view of FIG. A fuel injector 800 having a heated capillary flow passage tube 812 for fueling an internal combustion engine is shown in FIG. 9. Details of the tubes for fueling the internal combustion engine are shown in FIG. 9A. As shown, an axially movable rod 850 is located inside the capillary flow passage 812. The distal end 816 of the capillary flow passage 812 is deployed and the distal end 852 of the axially movable rod 850 is tapered to form a valve 854, where the axial movement of the rod 850 is controlled by the valve ( 854) to open and close. As can be appreciated, repeated movement of the axially movable rod 850 is performed to frictionally remove the stack formed during operation of the fuel injector of the present invention.

Referring now to FIG. 10, another embodiment of the present invention is shown in partial cross-sectional view. A fuel injector 900 having a heated capillary flow passage tube 912 for fueling an internal combustion engine is shown in FIG. 10. Details of the tubes for fueling the internal combustion engine are shown in FIG. 10A. As shown, an axially movable rod 950 is located inside capillary flow passage 912. The distal end 916 of the capillary flow passage 912 is deployed and the distal end 952 of the axially movable rod 950 is tapered to form a valve 954, where the axial movement of the rod 950 is controlled by the valve ( 954). A plurality of brushes 960 also arranged inside the capillary flow passage 912 is arranged along the axial movable rod 950 to clean the capillary flow passage 912. As can be appreciated, repeated movement of the axially movable rod 950 is performed to frictionally remove the stack formed during operation of the fuel injector of the present invention.

Referring now to FIG. 11, another exemplary embodiment of the present invention is shown in partial cross-sectional view. The fuel injector 1000 has a plurality of capillaries 1012 arranged in parallel for supplying fuel to the internal combustion engine. In this embodiment, the fuel is capillary heated along its length 1020 defined by the electrical connections in a manner similar to that shown in FIG. 1 during certain engine operating periods (eg, cold start, warm up and accelerated states). The engine may be supplied by one or more of the flow passages 1012. Heating to one or more capillaries of this type can be deactivated because less vaporized fuel is required for the reduction of unburned hydrocarbons.

12 shows that fuel injectors 10 having capillary flow passages 12 are arranged in some way such that the liquid fuel flowing through them reduces the power demand of the fuel vaporization resistance heater 20 to reduce the recycle exhaust gas EGR. It is shown in simple form whether it can be heated to elevated temperatures through use. As shown, the capillary flow passage 12 passes through the EGR passage 1100 for heating. During initial engine start-up, a resistive heater 20 comprising sections of capillary flow passages 12 or individual resistive heaters is connected to a power source such as a battery to initially vaporize the liquid fuel F. After about 20 seconds of operation, the capillary flow passage 12 can be heated by the heat of the EGR to otherwise reduce the power required for continuous vaporization of the fuel by the resistance heater 20. Thus, the fuel in the capillary flow passage 12 can be vaporized without using the resistance heater 20 so that power can be conserved.

13 is a vaporized fuel supply valve in fluid communication with a liquid fuel source 2010 and a liquid fuel injection path 2260, a liquid fuel supply valve 2220, a liquid fuel source 2010, and a capillary flow passage 2080. An example of a control system 2000 used to operate 2210 and an internal combustion engine 2110 having an oxidizing gas supply valve 2020 in fluid communication with an oxidizing gas source 2070 and a capillary flow passage 2080. A schematic diagram is shown. The control system includes a plurality of input signals from various engine sensors such as engine speed sensor 2060, intake manifold air thermocouple 2062, coolant temperature sensor 2064, exhaust air-fuel ratio sensor 2150, fuel supply pressure 2012, and the like. Controller 2050 that typically receives. In operation, the controller 2050 executes a control algorithm based on one or more input signals and then outputs the signal 2024 to the oxidant supply valve 2020, liquid fuel, for cleaning the occluded capillary passageway in accordance with the present invention. Heating power command 2044 for an output signal 2014 for supply valve 2220, an output signal 2034 for vaporized fuel supply valve 2210, and a power source for supplying power to heat capillary 2080. Create

In operation, the system according to the invention can be configured to feed back the heat generated during combustion through the use of exhaust gas recirculation heating, such that the liquid fuel passes through the capillary flow passage 2080 and is electrically or otherwise capillary The heating is sufficient to substantially vaporize the liquid fuel as it reduces, eliminates or supplements the need for heating the flow passage 2080.

Yes

Example 1

A test was conducted in which the JP8 jet fuel was vaporized by supplying fuel to a capillary flow passage heated at a constant pressure by a micro diaphragm pump system. In these tests, capillary tubes of different diameters and lengths were used. Tubes have an inner diameter (ID) and an outer diameter (OD), i.e. 0.025 ID / 0.046 OD (0.010 ID / 0.018 OD), 0.033, in lengths of 2.5 to 7.6 cm (1 to 3 in) and in the following cm (in) ID / 0.083 OD (0.013 ID / 0.033 OD), and 0.043 ID / 0.064 OD (0.017 ID./0.025 OD). Heat for vaporizing liquid fuel is generated by passing a current through a portion of the metal tube. Droplet size distributions are measured using a Spray-Tech laser diffraction system manufactured by Malvern. Droplets with a Sauter mean particle size (SMD) of 1.7 to 4.0 μm were produced. SMD is the diameter of droplets whose surface-to-volume ratio is the same as that of the entire spray and relates to the mass transfer properties of the spray.

Example 2

The test was again performed using gasoline vaporized by fueling a capillary flow passage heated at a constant pressure by a micro diaphragm pump system. In these tests, capillary flow passages of different diameters and lengths were used. The table below shows the experimental results for various capillary tube types.

Inner diameter cm (in) Heating length cm (in) Fuel pressure kg / cm 2 (psig) result 0.069 (0.027) 17.2 (6.75) 5.3 (75) Full vaporization flow and 180 mg / s flow rate generation 0.074 (0.029) 18.4 (7.25) 4.6 (65) High flow rate generation with 20V heating voltage 0.051 (0.020) 15.2 (6.0) 4.9 (70) Generate a flow rate of at least 200 mg / s with substantially adequate steam characteristics

Example 3

In tests using a Ford 4.6 liter V8 engine, one bank of four cylinders was modified to include the fuel supply of the present invention as shown in FIG. The capillary heating element is mounted with the tip of the capillary tube flush with the intake port wall, which is the position of the stock fuel injection nozzle. The test is performed with continuous injection (100% duty cycle) and thus fuel pressure is used to regulate fuel vapor flow rate.

Referring to Figure 14, a graph is provided showing the results of the capillary fuel supply during the first 20 seconds of cold start of the engine. Plot line 1 shows the engine speed in rpm as time passes along the x-axis. Plot line 2 shows fuel flow rate in g / s as time passes along the x-axis. Plot line 3 represents the lambda as time passes along the x-axis, where lambda 1 represents the theoretical air-fuel ratio. Plot line 4 shows the total hydrocarbon emissions output from the exhaust of the engine as ppm methane as time progresses along the x-axis.

As shown by plot line 3 of FIG. 14, the initial excess fuel supply required for stock engine hardware and control schemes is eliminated by use of the fuel supply device of the present invention. That is, the fuel supply device of the present invention efficiently vaporizes liquid fuel during the initial start-up period so that the engine starts at almost the theoretical air-fuel ratio. FIG. 15 is a graph showing the emission reduction resulting from the near theoretical state start (plot line 6) achieved by the fuel supply of the present invention as compared to the conventional excess fuel supply start plan (plot line 5). Specifically, the results in FIG. 15 show that the fuel supply of the present invention reduces the total hydrocarbon emissions by 46% during the first 10 seconds of cold start compared to the stock form requiring excess fuel supply. The area shown in circle 7 shows a dramatic reduction in hydrocarbon emissions during the first 4 seconds after engine start.

Example 4

Tests were conducted to demonstrate the benefits of oxidative cleaning techniques for heated capillary flow passages using known, unadded sulfur-free gasoline to produce high levels of laminate composition. The capillary flow passages employed in these tests were 5.1 cm (2 in) long heated capillary tubes made of stainless steel with an inner diameter of 0.058 cm (0.023 in). The fuel pressure is maintained at 0.7 kg / cm 2 (10 psig). Power is supplied to the capillary to achieve various levels of R / R ₀ , where R is the heated capillary resistance and R ₀ is the capillary resistance under ambient conditions.

16 shows a graph of fuel flow rate versus time. As shown, for this gasoline without a cleaning additive, significant occlusion was experienced for a very short time period with 50% flow rate loss observed for about 10 minutes.

After significant occlusion was experienced, the fuel flow was interrupted and air at 0.7 kg / cm 2 (10 psig) was replaced. Heating was provided during this period and after about one minute a significant wash was achieved with the flow rate returned to the previous level.

Example 5

This example shows that occlusion is much less severe in the heated capillary flow passage of Example 4 when a commercial grade gasoline employing an effective additive package is used. As shown in FIG. 17, less than 10% reduction in fuel flow rate was experienced after operation of the apparatus for nearly 4 hours.

Example 6

In order to compare the effects of the cleaning additives on various gasoline and occlusions, five test fuels were flowed into the heated capillary flow passage of Example 4. The fuels tested included unadded base gasoline containing 300 ppm sulfur, unadded base gasoline containing no sulfur, sulfurless based gasoline added commercially available commercial additives (additive A), and other commercially available commercial additives ( Sulfur-based gasoline added with additive B).

As shown in FIG. 18, the additive fuel acts similarly, and the unadded fuel experiences severe occlusion after less than one hour of operation.

Example 7

This example shows a time course operation of a capillary flow passage acting on an unadded jet fuel (JP-8) and an additive no operating on a capillary flow passage having an ID of 0.036 cm (0.014 in) and a length of 5.1 cm (2 in). .2 compare the same capillary flow passages acting on diesel fuel; The fuel pressure is set at 1.1 kg / cm 2 (15 psig). Power is supplied to the capillary to achieve a level of R / R ₀ of 1.19, where R is the heated capillary resistance and R ₀ is the capillary resistance under ambient conditions.

As shown in FIG. 19, the fuel behaves similarly over the first 10 minutes after operation, after which the diesel fuel experiences more severe blockages.

Example 8

Experiments were conducted to demonstrate the efficiency of the oxidative cleaning technique for capillary flow passages heated using no additive No. 2 diesel fuel known to produce high levels of laminated composition. The capillary flow passages employed in these tests were 5.1 cm (2 in) long heated capillary tubes composed of stainless steel with an inner diameter of 0.036 cm (0.014 in). The fuel pressure is maintained at 1.1 kg / cm 2 (15 psig). Power is supplied to the capillary to achieve a level of R / R ₀ of 1.19, where R is the heated capillary resistance and R ₀ is the capillary resistance under ambient conditions.

20 shows a graph of fuel flow rate versus time. As shown, for this fuel without a cleaning additive, significant occlusion was experienced for a very short time period with 50% flow rate loss observed after about 35 minutes of continuous operation.

In the second operation, after 5 minutes of operation, the fuel flow is interrupted and air at 0.7 kg / cm 2 (10 psig) is replaced for 5 minutes. This procedure is repeated every 5 minutes. As shown in FIG. 20, the oxidative cleaning process tends to increase fuel flow rate substantially at every instant and slow down the overall decrease in fuel flow rate over time. However, the efficiency of the process is somewhat less than that achieved using unadded gasoline as described in Eq.

Example 9

A test was conducted to demonstrate the effect of a commercial grade anti-fouling cleansing agent mixed with No. 2 diesel fuel of Example 8 on fuel flow rate over time in a heated capillary flow passage. The capillary flow passages employed for these tests were likewise 5.1 cm (2 in) long heated capillary tubes made of stainless steel with an inner diameter of 0.036 cm (0.014 in). The fuel pressure is maintained at 1.1 kg / cm 2 (15 psig) and power is supplied to the capillary to achieve a level of R / R ₀ of 1.19.

FIG. 21 shows a comparison of fuel flow rate versus time for added No. 2 diesel fuel and no additive diesel fuel. As shown, for fuels that do not contain a cleaning additive, significant occlusion has been experienced in a very short time period with 50% loss of flow rate observed in about 35 minutes of continuous operation, but the same base fuel containing the cleaning agent There is much less occlusion for an extended period of time.

Although the invention has been illustrated and described in detail in the drawings and above description, the disclosed embodiments are exemplary and not indicative of limitation. All changes and modifications that fall within the scope of the invention are required to be protected. For example, a plurality of capillary passages may be provided in which fuel passes through the passages in parallel when higher volume flow rates are required.

Claims (20)

A fuel injector for vaporizing liquid fuel for use in an internal combustion engine, (a) at least one capillary flow passage having an inlet end and an outlet end and comprising a channel formed in a monolithic body or a multilayer ceramic body made of a material selected from the group consisting of ceramics, polymers, metals and composites thereof; (b) a fluid control valve for placing the inlet end of said at least one capillary flow passage in fluid communication with a liquid fuel source and for introducing liquid fuel into a substantially liquid state; And (c) arranged along said at least one capillary flow passage, heating at least a portion of said liquid fuel in said at least one capillary flow passage to a level sufficient to change from said liquid state to a vapor state and said at least one capillary tube And a heat source operable to supply a stream of substantially vaporized fuel from said outlet end of the flow passage. The fuel injector of claim 1, wherein the capillary flow passage is formed in a ceramic body. 3. The fuel injector of claim 1 or 2, further comprising: (d) means for cleaning the stack formed during operation of the apparatus. 4. The oxidant control valve of claim 3, wherein the stack cleaning means comprises an oxidant control valve for disposing the fluid control valve, the heat source and the at least one capillary flow passage in fluid communication with an oxidant, the heat source also being at least one. The oxidant control valve operable to heat the oxidant in a capillary flow passage of a level to a level sufficient to oxidize the stack formed during heating of the liquid fuel, the oxidant control valve for placing the at least one capillary flow passage in fluid communication with an oxidant. Is operable to alternately introduce an oxidant into the capillary flow passage and introduction of the liquid fuel and to enable in-situ cleaning of the capillary flow passage when the oxidant is introduced into the at least one capillary flow passage. Fuel injector. 5. The method of claim 4, wherein the at least one capillary flow passage comprises a plurality of capillary flow passages, each of the capillary flow passages in fluid communication with a fuel source and an oxidant gas source, the fluid control valve and the oxidant control valve. The fuel injector is composed of a single valve mechanism operated by the controller. 6. The fuel injector of claim 4 or 5, wherein the oxidant comprises air, exhaust gas, steam, and mixtures thereof. 4. The fuel injector of claim 3, wherein the stack cleaning means comprises means for friction removing the stack formed during operation of the apparatus. 4. The method of claim 3 wherein the stack cleaning means comprises a solvent control valve for disposing the fluid control valve and the at least one capillary flow passage in fluid communication with the solvent, wherein the solvent control valve comprises the at least one capillary tube. The solvent control valve, disposed at one end of the flow passage, for arranging the at least one capillary flow passage in fluid communication with the solvent, performs alternating introduction of the solvent and introduction of the liquid fuel into the capillary flow passage. And enable the in-situ cleaning of the capillary flow passage when the solvent is introduced into the at least one capillary flow passage. 4. The method of claim 3, wherein said stack cleaning means comprises said fluid control valve, said fluid control valve being arranged in fluid communication with said at least one capillary flow passage, said solvent being in said at least one capillary flow. A fuel injector operable to enable in-situ cleaning of the capillary flow passage when introduced into the passage. 10. The fuel injector of claim 9, wherein the solvent comprises liquid fuel from the liquid fuel source, and the heat source is phased-out during washing of the capillary flow passages. The fuel injector of claim 1, further comprising a nozzle for atomizing a portion of the liquid fuel. 12. The fuel injector of any one of the preceding claims, further comprising a solenoid for operating said fluid control valve for positioning said inlet end in fluid communication with said liquid fuel source. The fluid control valve of claim 1, wherein the fluid control valve has a valve element at the outlet end of the at least one capillary flow passage to open and close the outlet end of the at least one capillary flow passage. A fuel injector comprising a solenoid operated valve stem. The non-capillary liquid fuel flow passage further comprising: a non-capillary liquid fuel flow passage having an inlet end and an outlet end, wherein the inlet end is the liquid fuel supply source. And the non-capillary liquid fuel flow passage in fluid communication with the fuel injector nozzle at the outlet end. The fuel injector of claim 1, wherein the heat source comprises a resistance heater. As a fuel system for use in an internal combustion engine, (a) (i) at least one capillary flow having an inlet end and an outlet end and comprising channels formed in a monolithic body or multilayer ceramic body made of a material selected from the group consisting of ceramics, polymers, metals and composites thereof Passage; (Ii) a fluid control valve for arranging said inlet end of said at least one capillary flow passage in fluid communication with a liquid fuel source and for introducing said liquid fuel into a substantially liquid state; And (iii) arranged along the at least one capillary flow passage, heating at least a portion of the liquid fuel in the at least one capillary flow passage to a level sufficient to change from the liquid state to the vapor state and the at least one capillary tube A plurality of fuel injectors each including a heat source operable to supply a stream of substantially vaporized fuel from an outlet end of the flow passage; (b) a liquid fuel supply system in fluid communication with the plurality of fuel injectors; And (c) a controller for controlling the supply of fuel to the plurality of fuel injectors. 17. The fuel system of claim 16, wherein the capillary flow passage is formed in a ceramic body. 18. The fuel system of claim 16 or 17, further comprising means for cleaning the stack formed during operation of the apparatus. As a method of supplying fuel to an internal combustion engine, (a) supplying liquid fuel to at least one capillary flow passage of the fuel injector; (b) heating the liquid fuel in the at least one capillary flow passage to allow a stream of substantially vaporized fuel to pass through the outlet of the at least one capillary flow passage; (c) supplying the vaporized fuel to a combustion chamber of the internal combustion engine, Wherein the capillary flow passage comprises a channel formed in a monolithic body or a multilayer ceramic body made of a material selected from the group consisting of ceramics, polymers, metals and composites thereof. 20. The method of claim 19, further comprising periodically cleaning the at least one capillary flow passage.