CN101044313B - Fuel injection valve - Google Patents

Abstract

A fuel injection valve (100) is provided for introducing a fuel into an engine and controlling fuel flow to reduce variability between injection events. The fuel injection valve (100) employs an arrangement for a valve nozzle (114, 414, 514) that cooperates with a valve needle (110, 310, 410, 510) to provide a range of needle movement within which the fuel mass flow rate is substantially constant. This can be achieved by providing a restriction (d1, d2) with a constant flow area for a predetermined range of needle movement. The method comprises commanding a valve needle (110, 310, 410, 510) to a position within the predetermined range of needle movement to reduce variability in the fuel mass flow rate, particularly when the engine is idling or operating under low load conditions. Valve needle lift is variable during an injection event and from one injection event toanother injection event.

Description

fuel injection valve

technical field

The invention relates to a fuel injection valve for controlling the flow of fuel into an internal combustion engine and to a method of operating such a fuel injection valve. More particularly, the fuel injection valve includes a nozzle arrangement that provides a substantially constant flow rate for a predetermined range of needle movement.

Background technique

The fuel injection valve can use a number of control strategies for controlling the total amount of fuel introduced into the combustion chamber of the internal combustion engine. For example, some parameters that can be manipulated by well known control strategies are the pulse width of the injection event, fuel pressure, and valve needle lift.

The "pulse width" of an injection event is defined herein as the time that the fuel injection valve is open to allow fuel to be injected into the combustion chamber. Assuming constant fuel pressure and constant valve needle lift, longer pulse widths generally result in a greater amount of fuel being introduced into the combustion chamber.

However, fuel pressure need not be constant from one injection event to another, and may be increased to increase the total amount of fuel introduced into the combustion chamber. Conversely, fuel pressure may be reduced to inject a smaller amount of fuel into the internal combustion engine, such as during idle or low load conditions.

As another example, some types of fuel injection valves may control needle lift to affect the total amount of fuel introduced into the combustion chamber. An increase in needle lift generally corresponds to an increase in the total amount of fuel being injected, and some fuel injection valves may be controlled to hold the needle in an intermediate position between the closed and fully open positions to allow a ratio of maximum Small flow of traffic. To control needle lift, fuel injection valves may use a mechanical device or actuator that may be controlled to lift and hold the needle in an intermediate position between a closed position and a fully open position.

European patent specification EP 0 615 065 B1 ("shibata") discloses a fuel injection valve for injecting liquid fuel using an injection pump having a cam-driven plunger that reciprocates to increase The fuel pressure thereby actuates the fuel injection valve. The cam has a low speed region where the fuel supply speed of the pump is low and a high speed region where the fuel supply speed is high so that the plunger can move at varying speeds. The injection valve has an elongated pin formed on the valve needle for maintaining the size of the fuel passage at the injection hole substantially constant when the pin is located in the injection hole even when the valve needle moves, so that the fuel injection mass flow rate is substantially constant until The pin is lifted out of the spray hole. Shibata discloses an apparatus and method that can be used to create fuel injection mass flow during an injection event so that the fuel injection rate is initially low (when the pin is in the injection hole) and then increases to Higher fuel injection rate (when the pin is lifted from the injection hole). However, because the injection pump is mechanically operated using a cam and plunger arrangement, the shape of the fuel injection mass flow is generally the same for each injection event. For each injection event, the valve needle moves continuously from a closed position to a fully open position, and then back to a closed position, with a pin at the end of the needle providing a limit for generating a stepped injection pulse. Shibata does not disclose an apparatus or method for regulating fuel mass flow by actuating a valve needle operable to maintain the valve needle in a neutral position, and a method whereby during and from an injection event From one injection event to another, the valve needle lift can vary. That is, Shibata does not disclose an apparatus or method that, for the continuation of the injection event, allows the valve needle to partially lift to an intermediate position, thereby providing a lower mass flow for the entire injection event, and also allows the valve to lift to the fully open position for another jetting event.

A difficulty with known control strategies is controlling the total amount of fuel injected into the combustion chambers of the internal combustion engine during idling or low load conditions. Under these conditions, the fuel injection valve is required to inject only a small amount of fuel into the combustion chamber, and even a small change in the total amount of fuel injected into the combustion chamber can cause a significant change in the total amount of fuel injected, which can cause Unstable operation. Under conditions of high load, changes in the total amount of fuel of the same magnitude have less effect on the operation of the internal combustion engine, because when this difference is considered as a percentage of the total amount of fuel injected, they represent suitable injection Very small changes in the difference between the total amount of fuel and the actual total amount of injected fuel.

If the control strategy only manipulates the pulse width in order to control the total amount of fuel injected during idle and low load conditions, this strategy would result in pulse widths that are too short to provide stable and efficient combustion. Therefore, simply shortening the pulse width to reduce the total amount of fuel injected is not a suitable strategy in idling or low load conditions.

Sufficiently long pulse widths for idle or low load conditions can be achieved by reducing fuel pressure. For liquid fuels, this is a viable strategy, but it requires a system for controlling fuel pressure, which adds cost and complexity to the fuel injection system. For example, known liquid fuel systems may reduce fuel pressure by returning a portion of the high pressure fuel to the fuel tank. With liquid fuels, there is a limit to how low the pressure can be dropped because a minimum fuel pressure is required to atomize the fuel when it is introduced into the combustion chamber of the internal combustion engine. However, this method is more difficult for gaseous fuels. Because gas is a compressible fluid, much more gaseous fuel must be returned to the tank for a similar reduction in fuel pressure compared to liquid fuel, and if the gaseous fuel tank is pressurized, then the tank pressure When the pressure of the fuel rail is exceeded, return flow is not possible. Therefore, it is not suitable to rapidly depressurize gaseous fuels without venting some of them into the atmosphere. It is therefore difficult to control fuel pressure to obtain a suitable responsiveness for controlling fuel injection mass flow at an injection event or from one injection event to the next. It is also difficult to control fuel pressure and injection valve operation to accurately inject a precise amount of fuel with a precision suitable for each injection event, and again, only small changes in the total amount of fuel can cause unstable operating conditions. Therefore, controlling fuel injection pressure alone is not a suitable strategy for regulating fuel mass flow through a fuel injection valve.

If the fuel injection valve is operable to control needle lift, the flow rate can be controlled to provide a sufficiently long pulse width to inject a suitable amount of fuel for an internal combustion engine operating at idle or under low load conditions. As shown in Japanese Patent Application No. 60031204, the fuel injection valve may be provided with a stopper movable to limit the lift of the valve needle. This type of mechanism adds considerable complexity to the fuel injection valve, and thus entails higher manufacturing costs, increased space requirements for mounting the injection valve assembly, maintenance costs, and reliability considerations.

In another approach, fuel injection valves are known to control the total amount of fuel injected by using a variable orifice area. That is, the injection valve may have two sets of holes so that when a smaller amount of fuel is to be injected, the valve is operable to inject fuel through only one set of holes, and when a larger amount of fuel is to be injected the fuel passes through both sets. The hole is sprayed. One example of such an injection valve is disclosed in US Patent No. 4,546,739. Like other known mechanical solutions, this arrangement has the associated disadvantages of increased complexity and high manufacturing costs, maintenance costs and reliability considerations.

Another type of fuel injection valve may be directly actuated by a strain gauge actuator that may be commanded to lift the valve needle to any position between its closed and open positions. Examples of directly actuated fuel injection valves using strain gauge actuators are disclosed in commonly owned US Patent Nos. 6.298.829, 6,564,777, 6,575,138 and 6,584,958, which are hereby incorporated by reference in their entirety. For example, if the strain gauge actuator is a piezoelectric actuator, by controlling the electrical charge applied to the actuator, valve needle lift can be commanded to the appropriate lift position. However, even with this approach, there will still be variability in fuel flow from one injection event to the next because the actual valve needle lift cannot always exactly match the commanded lift. Variability in actual valve lift can be caused by a number of factors including, for example, one or more changes in combustion chamber pressure, changes in fuel pressure, the effects of differential thermal expansion/contraction within the fuel injection valve, and fuel Wear of components inside the injection valve. Thus, even for fuel injection valves using actuators that allow lift control, there will still be an element of variability in the actual lift that is still large enough to cause variability in the total amount of fuel injected .

The instability of the internal combustion engine at idle speed and low load results in higher fuel consumption, exhaust emissions, noise and vibration of the internal combustion engine. Therefore, there is a need for an apparatus and method that provides a more stable means of controlling the total amount of fuel injected during each injection event when the internal combustion engine is idling or under low load conditions, and Combustion stability in these states can be improved.

For compression ignition internal combustion engines burning gaseous fuels, it is advantageous to shape the fuel injection rate to start the injection event with an initial low mass flow followed by a higher mass flow until the end of the fuel injection event. One such example is disclosed in commonly owned and co-pending U.S. Patent Application Serial No. 10/414,850, entitled "Internal Combustion Engine With Injection Of Gaseous Fuel," which is hereby incorporated by reference in its entirety. It is difficult to operate conventional fuel injection valves to provide the stepped flow characteristics that are required to achieve this result. If a fuel injection valve can be manufactured that provides a substantially constant mass flow for a predetermined range of needle motion such that this constant mass flow corresponds to an initial low mass flow for a stepped injection event, then for the idle to full This feature can be used to improve injection stability and engine performance at all operating states of load.

Contents of the invention

A fuel injection valve for introducing fuel into an internal combustion engine is disclosed. The fuel injection valve includes:

a. a valve body, including a nozzle, said valve body defining a fuel cavity within the valve body;

b. a valve needle movable within the nozzle between a closed position and a fully open position to allow fuel to flow from the fuel chamber and through the nozzle into the internal combustion engine, wherein in the closed position the valve a needle seated against a valve seat associated with the nozzle, the needle being furthest spaced from the valve seat in the fully open position; and

c. an actuator for actuating the valve needle, the actuator being operable to maintain the valve needle in an intermediate position between the seated position and the fully open position, during an injection event and Valve needle lift may vary from one injection event to another. That is, the valve needle lift may vary because, for example, the valve needle may be commanded to different positions at different times during a single injection event, and held in different positions if desired. The valve needle lift can also vary from one injection event to another, since the shape of the valve needle lift versus time curve can be different for different injection events, for example, can have a relatively low The valve needle lift and rectangular shape, and can have a stepped shape for high load conditions, where the second stage is substantially larger than the first stage.

When the valve needle is between a first intermediate position near the closed position and a second intermediate position spaced from the first intermediate position, the valve needle and valve body are shaped to cooperatively provide the valve needle and the constant flow area between the valve body. The constant flow region restricts flow through the nozzle such that mass flow is substantially constant for a range of valve needle motion, wherein the range of motion is bounded by the first and second intermediate positions, wherein the A constant flow area is located in the fuel chamber upstream of the valve seat.

To reduce flow variability when the needle is between the first and second intermediate positions, the constant flow area is preferably smaller than the flow area of the opening between the seats so that when the needle is in the first and second intermediate positions Between , the constant flow area controls the fuel mass flow through the fuel injection valve.

The constant flow area may be provided by an annular gap between the valve needle and the valve body, or by a groove formed in the valve body or the valve needle. The raised portion between the slots can be used as a guide for the valve needle to increase the stability of positioning the valve needle on the valve seat.

In a preferred embodiment, the fuel injection valve further comprises a strain gauge actuator for directly actuating the valve element. The strain gauge actuator may include a transducer selected from the group consisting of piezoelectric, magnetostrictive, and electrostrictive transducers. The electronic controller may be programmed to send command signals to the actuator to move the valve needle between a closed position and a fully open position, and to positions therebetween according to a predetermined waveform.

The fuel injection valve may also include an amplifier disposed between the actuator and the valve element to amplify the strain produced by the actuator, thereby causing a larger corresponding movement of the valve element. The amplifier may be a hydraulic displacement amplifier, or it may use at least one rod to mechanically amplify the strain.

In a preferred embodiment, the fuel is introduced into the fuel chamber in a gaseous state. The fuel may be selected from the group consisting of natural gas, methane, ethane, liquefied petroleum gas, lighter combustible hydrocarbon derivatives, hydrogen and mixtures thereof.

The valve needle may be an inwardly opening needle such that when moving from the closed position towards the open position the valve needle may move in an inward direction opposite to the direction of fuel flow. In this embodiment, the nozzle may include a closed end having at least one aperture through which fuel may be injected when the valve needle is spaced from the valve seat. In a preferred embodiment, the nozzle includes a plurality of holes through which the fuel can be injected when the valve needle is spaced apart from the valve seat, and the total opening of the plurality of holes area is larger than the constant flow area. The aggregate open area of the plurality of holes provides minimal restriction to fuel flow through the nozzle when the valve needle is in the fully open position and thereby controls the mass of fuel flowing through the fuel injection valve flow.

In another embodiment, the fuel injection valve may further include a third intermediate position spaced apart from said second intermediate position, defining a boundary of a second range of needle movement between the second and third intermediate positions. When the valve needle is between the second and third intermediate positions, the valve body and valve needle are shaped to cooperatively provide a second constant flow area that is restricted through the nozzle such that the mass flow rate is substantially constant, but higher than when the valve needle is between the first and second intermediate positions.

By way of example, a preferred embodiment of a fuel injection valve for injecting fuel directly into a combustion chamber of an internal combustion engine is shown and described. Those of ordinary skill in the art will appreciate that other arrangements for the valve body and needle of the fuel injection valve are possible without departing from the spirit and scope of the present disclosure. The disclosed range of fuel injection valves includes a nozzle and a valve needle shaped to cooperate with each other such that when the valve needle is in a first intermediate position near a closed position and spaced apart from said first intermediate position Between the second intermediate position of , a substantially constant pressure drop is created as fuel flows through the nozzle so that the mass flow rate is substantially constant for a range of valve needle motion bounded by first and second Intermediate positions are limited.

A method is provided for regulating a fuel mass flow through a nozzle of a fuel injection valve into an internal combustion engine. The methods include:

actuating the valve needle to control needle lift which may be varied in response to measured engine operating conditions, including engine load and speed;

When a predetermined constant fuel mass flow is desired, the valve needle is commanded to move to a position between first and second predetermined intermediate positions between the closed position and the fully open position , wherein the fuel injection valve is designed to allow a substantially constant fuel mass flow when the valve needle is between first and second intermediate positions and when the pressure of the fuel is constant; and

commanding the valve needle to move between the closed and fully open positions but not between the first and second intermediate positions when a fuel mass flow different from the predetermined constant fuel mass flow is desired positions between, wherein the valve needle and the valve body are form-fittingly designed to provide a constant flow area when the valve needle is between the first and second intermediate positions, and wherein in the In the closed position, the valve needle is forced against a valve seat on which the constant flow area is located.

Preferably, the method further comprises commanding said valve needle to an intermediate point between first and second intermediate positions when said substantially constant mass flow is desired. Because there will be some variability between the commanded valve needle position and the actual valve needle position, commanding the valve needle to the midpoint of the range of motion reduces the likelihood that the actual valve needle position will be within a range determined by the predetermined Possibilities outside the range of motion defined by the first and second intermediate positions are determined. Overall, this reduces the variability of fuel mass flow delivered into the combustion chamber.

In a preferred embodiment of the method, said substantially constant fuel mass flow corresponds to a suitable fuel mass flow for idle or low load conditions. As mentioned above, under these conditions the internal combustion engine is most susceptible to changes in the mass flow of fuel, since the total amount of fuel required to be injected is already small compared to when the internal combustion engine is operating under higher load conditions, and Even small changes in fuel mass flow can adversely affect stable internal combustion engine operation, with corresponding adverse effects on internal combustion engine performance characteristics, such as emissions, noise and/or efficiency of the internal combustion engine.

In a preferred embodiment of the method, said substantially constant fuel mass is regulated by providing a flow restriction in said nozzle with a constant flow area when said valve needle is between a first and a second intermediate position flow. When the second intermediate position corresponds to a valve needle lift greater than that of the first intermediate position, by moving the valve needle from the second intermediate position towards the fully open position, the fuel Mass flow can be increased substantially and gradually.

The method may also include commanding the valve needle to a position between the second intermediate position and a third intermediate position when a second substantially constant mass flow rate is desired, wherein the second intermediate position corresponds to a ratio greater than the first intermediate position. The first intermediate position has a greater needle lift, and the third intermediate position corresponds to a greater needle lift than the second intermediate position. The fuel injection valve may be designed with a flow restriction such that a first restricted flow area is smaller than a second restricted flow area which is substantially constant when the valve needle is located between the second and third intermediate positions. In this embodiment of the method, the fuel mass flow may be substantially and gradually increased by moving the valve needle from the third intermediate position towards the fully open position. For example, a first constant mass flow may be selected when the internal combustion engine is idling, and a second constant mass flow may be selected when the internal combustion engine is operating at a predetermined low load condition.

The method preferably includes injecting fuel directly from the nozzle into a combustion chamber of the internal combustion engine. By injecting fuel directly into the combustion chamber, the internal combustion engine can maintain the compression ratio and efficiency of an equivalent internal combustion engine burning diesel fuel. If fuel is injected into the intake system upstream of the intake valve, in order to avoid premature deflagration of the fuel, the total amount of injected fuel must be limited and/or the compression ratio of the internal combustion engine must be reduced.

The invention is particularly applicable to fuels which are in the gaseous state when flowing through the nozzle. Accordingly, the method may also include introducing fuel in gaseous state into the nozzle. For example, the fuel may be selected from the group consisting of natural gas, methane, ethane, liquefied petroleum gas, lighter combustible hydrocarbon derivatives, hydrogen and mixtures thereof.

A preferred embodiment of the method further includes directly actuating the valve needle with a strain gauge actuator that can be activated to produce a corresponding movement of the valve needle. Strain gauge actuators are generally suitable for implementing the disclosed method because they can be controlled to command the valve needle to move to and remain there any intermediate position between the closed and fully open positions. The strain gauge actuator preferably comprises a transducer selected from the group consisting of piezoelectric, magnetostrictive and electrostrictive transducers.

The method may also include controlling the injection pulse width to assist in controlling the total amount of fuel injected during the injection event such that the pulse width may vary from one injection event to another in response to a predetermined measured operating state of the internal combustion engine. Variety. However, pulse width control alone is not a suitable strategy for regulating the mass amount of injected fuel, and pulse width control can be combined with the disclosed method to provide greater flexibility so that a suitable mass amount of fuel can be introduced In the combustion chamber, as determined from the measured operating state of the internal combustion engine and with reference to a map of the internal combustion engine characteristic. For example, some engine operating states may include engine speed and engine load. Other operating conditions may also be monitored, and the electronic control unit may be programmed to determine if any adjustments need to be made to trim other variables such as fuel temperature; intake air pressure, fuel injection pressure, and in-cylinder pressure.

Similarly, the method may also include controlling the injection pressure to assist in controlling the total amount of fuel injected during the injection event, such that the fuel injection pressure from one injection event to another may respond to a predetermined measured internal combustion engine operating state changes.

A method of regulating fuel mass flow through a nozzle of a fuel injection valve into an internal combustion engine by controlling a valve needle position, the method comprising:

increasing fuel mass flow from zero to a first value by moving the valve needle from a closed position in which the valve needle is forced against the valve seat to a first intermediate position;

maintaining fuel mass flow substantially constant about the first value when the valve needle is between a first intermediate position and a second intermediate position, the second intermediate position being spaced apart from the first intermediate position;

gradually increasing fuel mass flow beyond said first value by moving said valve needle from said second intermediate position towards a fully open position;

Increase fuel mass flow to its maximum by moving the valve needle to the fully open position; and

actuating the valve needle to control needle lift in response to measured engine operating conditions, including engine speed and load, wherein the valve needle position is during and from one injection event to another Events can vary.

In a preferred method, the first value is the commanded fuel mass flow when the internal combustion engine is operating at idle or low load.

The preferred method may further comprise commanding the valve needle to move according to a stepped waveform having a relatively low mass flow during a first phase and a higher mass flow during a second phase, And wherein said first value is a fuel mass flow commanded for said first stage.

The method preferably includes moving the valve needle by actuating a strain gauge actuator that can be commanded to produce a linear displacement that is communicated to the valve needle. With such an actuator, the graph of displacement versus time can follow any commanded shape, and need not be the same shape for each injection event. For example, for an idle state, a small displacement having a substantially rectangular shape may be commanded. For higher loads, a stepped shape can be used where a relatively low initial displacement is followed by a higher actuator displacement.

Description of drawings

The drawings illustrate specific embodiments of the invention, but should not be considered as limiting the spirit and scope of the invention in any way.

1 is a schematic diagram of a directly actuated fuel injection valve operable to inject a substantially constant amount of fuel for a predetermined range of needle movement.

2A to 2C show schematic cross-sectional views of valve nozzles and needle tips such as may be used with the fuel injection valve of FIG. 1 . Figure 2A shows the valve needle in the closed position. Figure 2B shows that the needle is in a range that provides a constant flow region, resulting in a substantially constant flow for a range of needle motion. Figure 2C shows the valve needle lifting beyond the range of the constant flow region. Figures 2A through 2C illustrate one embodiment of a feature that may be used to make a fuel injection valve operable to inject a substantially constant amount of fuel for a predetermined range of needle movement.

Figures 2D and 2E show cross-sectional views through the section line labeled D/E in Figure 2A.

Figure 2D shows a simple concentric circular arrangement defining an annular constant flow area between the valve needle and valve body. Figure 2E provides an example of another embodiment where the constant flow area is provided by a plurality of grooves formed in the valve body.

3 is a schematic cross-sectional view of a nozzle including features for providing two distinct ranges of motion for an inwardly opening valve needle, wherein each range of motion provides a corresponding substantially constant flow, the substantially constant Constant flow is defined by the constant flow area provided within each range.

4A to 4C show schematic cross-sectional views of one embodiment of a valve nozzle for an outwardly opening valve needle. Figure 4A shows the valve needle in the closed position. Figure 4B shows a valve needle positioned in a range that provides a constant flow region, thereby producing a substantially constant flow for a range of needle motion. Figure 4C shows the valve needle lifting beyond the range of the constant flow region.

5 is a schematic cross-sectional view of an outwardly opening valve needle and valve nozzle cooperating with each other to provide two ranges of valve needle positions, both of which provide a substantially constant flow area, Fuel mass flow is thus substantially constant when the valve needle is positioned anywhere within these ranges.

Figure 6 is a graph of mass flow through a fuel injection valve nozzle versus needle lift. There are shown two embodiments, one with a single range of motion producing a substantially constant mass flow, and a second embodiment with two ranges of motion producing a corresponding substantially constant mass flow flow. The exemplary embodiments are compared with curves for the flow characteristics of conventional fuel injection valves.

FIG. 7 is a graph of commanded mass flow through a fuel injection valve. A number of commanded shapes are shown that can benefit from the stability that can be achieved using the disclosed nozzle and needle features to enhance flow characteristics through the fuel injection valve.

Detailed ways

The diagrams are not drawn to scale and some features may be exaggerated to better illustrate their function.

FIG. 1 is a schematic cross-sectional view of a fuel injection valve 100 that may be used to introduce fuel into an internal combustion engine. The valve body 102 houses the valve needle 110 , the actuator 120 and the transmission assembly 130 . Valve body 102 also defines a fuel chamber 104 that includes a fuel passage extending from coupling 106 and fuel inlet 108 through to valve seat 112 . The valve needle 110 is movable within the nozzle 114 between a closed position in which the valve needle 110 is seated against the valve seat 112 and a fully open position in which the valve needle 110 is furthest apart from the valve seat 112. . When the valve needle 110 is spaced from the valve seat 112 , fuel may flow from the fuel chamber 104 through the nozzle 114 into the internal combustion engine. In the example shown in FIG. 1 , fuel exits nozzle 114 through bore 116 . In the case of an outwardly opening needle (see eg Figures 4 and 5), fuel can exit the nozzle directly through the opening between the needle and the valve seat.

The disclosed features for affecting flow characteristics through a fuel injection valve are independent of the type of actuator used to cause the valve needle to move. Any actuator that can benefit from the disclosed arrangement can be controlled to affect the speed of valve needle actuation and/or control the position of the valve needle between the closed position and the fully open position. For example, solenoid actuated fuel injection valves can use the disclosed features, since the opening rate for the solenoid valve can be controlled to a certain degree by controlling the rate at which the force rises. That is, using an electromagnetic actuator, the speed of valve needle motion can be kept low during the beginning of the fuel injection event, prolonging the fuel flow rate during the latter portion of the fuel injection event before fuel mass flow increases. The time at which a constant relatively low fuel mass flow is introduced.

In a preferred embodiment, injection valve 100 includes a strain gauge actuator for direct actuation of needle 110 and provides the advantage of facilitating control of needle movement. A directly actuated fuel injection valve is defined herein as an injection valve that uses an actuator that can be activated to produce a mechanical movement that corresponds directly to the movement of the valve needle. In such directly actuated fuel injection valves, the mechanical movement from the actuator can be amplified by one or more mechanical rods or hydraulic amplification devices, but the movement of the actuator always corresponds to that of the valve needle. Sports are associated. In the example shown in FIG. 1 , transmission assembly 130 transmits motion from actuator 120 to valve needle 110 . The transmission assembly 130 includes a hydraulic displacement amplifier mechanism that amplifies the mechanical motion generated from the actuator 120 . In this example, actuation of the valve needle 110 occurs as follows. Actuator 120 may be activated to generate mechanical movement in an axial direction to move base 108 and plunger 124 toward nozzle 114 . The plunger 124 moves hydraulic fluid within the amplification chamber 132 . During the short period of the injection event, the volume of hydraulic fluid within the amplification chamber 132 remains substantially constant. Because the hydraulic fluid is substantially incompressible, to accommodate the fluid displaced by the plunger 124, the valve needle 110 moves in the opposite direction, away from the valve seat 112, thereby opening the valve 110 and initiating a fuel injection event. The amount of amplification is predetermined by the opposing end regions of the shoulders of the plunger 124 and the valve needle 110 both disposed in the amplification chamber 132 . That is to say, the greater the ratio between the end area of the plunger and the shoulder area of the valve needle, the greater the amplification of the valve needle stroke.

The actuator 120 may be commanded to vary the amount of strain during an injection event, thereby moving the valve needle 110 to a different open position, or to reduce the strain to zero, thereby ending the injection event.

Spring 126 biases valve needle 110 to the closed position and helps ensure that no spatial gap develops between actuator 120 , transmission assembly 130 , and valve needle 110 .

In the illustrated example, the transmission assembly 130 also includes a hydraulic fluid reservoir 134 . There is a much longer period of time between injection events than the time interval between fuel injection events, and there is sufficient time to allow some fluid to flow between the reservoir 134 and the amplifying chamber 132 when the engine is not running. Through the small gaps between the adjacent surfaces of the plunger 124 , needle 110 , valve body 102 and conduits 136 and 138 . This flow between the reservoir 134 and the amplification chamber 132 can compensate for leakage of hydraulic fluid between components and small dimensional changes that can result, for example, from differential temperature expansion/contraction and wear.

Seals 137 and 139 seal against leakage of hydraulic fluid into fuel chamber 104, which is necessary when valve 100 is used to inject gaseous fuel. Seal 139 is not necessary if the fuel is a liquid fuel and it is conveniently used as hydraulic fluid.

Strain-gauge actuators are generally controllable to produce any magnitude of strain between zero and the maximum amount of strain that can be produced by a given actuator. That is, the strain gauge actuator can be commanded to move the valve needle 110 to an intermediate position where it can be held for a suitable length of time. The controller can be programmed to command the actuator to change the amount of strain so that the valve needle 110 moves from an intermediate position to another open or closed position. This allows the movement of the valve needle 110 to be commanded to follow a predetermined waveform, which provides greater flexibility to control fuel mass flow during an injection event, and this flexibility can be used to improve combustion characteristics, thereby increasing Performance or efficiency, and/or reduction of exhaust emissions of undesirable combustion products, such as particulate matter or oxides of nitrogen or carbon, and/or reduction of internal combustion engine noise.

By way of example, the actuator 120 is shown schematically in FIG. 1 as a stack of piezoelectric elements for providing strain gauge actuation of the valve needle 110 . Those of ordinary skill in the art will understand that other strain gauge actuators, such as electrostrictive or magnetostrictive actuators, can be used to achieve the same result.

While strain-gauge actuators can be commanded to create the appropriate strain, there are various effects such as temperature, wear, fuel temperature, intake manifold pressure, and combustion chamber pressure that can vary from one injection event to another Events exert different effects on the valve pin position. Therefore, even if the actuator is commanded to produce a specific strain, which generally corresponds to the proper valve needle position, the actual valve needle position will still vary, and the difference between the actual position and the proper position can be significant enough To reduce combustion efficiency, especially when the internal combustion engine is idling or in a low-load state.

The features shown in Figures 2 to 5 illustrate embodiments of the needle and body that are shaped so that when the needle is within a range of motion, and when the mating surfaces hold each other In contrast, cooperatively provide a constant flow area between the valve needle and the valve body. This constant flow region restricts the flow through the nozzle so that the fuel mass flow is substantially constant. By commanding the valve needle to a position near the midpoint of this range, fuel mass flow is rendered substantially insensitive to small changes in valve needle position. All of the illustrated embodiments operate on the same principle and can be advantageously used to reduce the commanded fuel for idle and low load conditions, as well as for higher load conditions when a stepped injection profile is commanded Variability between mass flow and actual fuel mass flow.

Reference is now made to the embodiment shown in Figures 2A to 2C, which schematically illustrate the valve needle and nozzle arrangement. This arrangement can be used, for example, with the fuel injection valve of FIG. 1 . Accordingly, the same reference numerals are used in Figure 1 to refer to similar features in Figures 2A-2C. Only an end portion of the nozzle 114 is shown, with the valve body 102 defining a portion of the fuel chamber 104 surrounding the valve needle 110 . Figures 2A to 2C all show the same embodiment, but each figure shows the valve needle 110 in a different position.

In FIG. 2A , valve needle 110 is shown in a closed position, seating against valve seat 112 such that fuel cannot flow through bore 116 . To initiate a fuel injection event, valve needle 110 may move in the direction of arrow 150 . A valve needle such as that shown in Figures 1 to 3 can move away from the valve seat and in a direction opposite to the direction of fuel flow, known as an inwardly opening valve needle. In FIG. 2B , the valve needle 110 has been lifted off the valve seat 112 to the open position. In FIG. 2B , a portion of the vertical side of the needle 110 is opposed to the vertical wall of the valve body 102 provided by the shoulder 103 . The parallel and opposing vertical surfaces provide a flow restricting gap, denoted d1 , between them. The size of this gap is designed to provide a flow area that restricts fuel flow through the nozzle 114 to a substantially constant fuel mass flow rate for a range of valve needle motion as long as a portion of the vertical side of the valve needle 110 Opposite the vertical wall provided by the shoulder 103 . That is, because the mating vertical surfaces forming the gap are parallel to each other, the size of the gap remains constant for a certain range of needle motion. In FIG. 2C , needle 110 has been lifted beyond the point where the vertical surfaces of needle 110 and shoulder 103 face each other. Beyond this point, as the valve needle 110 moves further away from the valve seat 112, the flow area between the valve needle 110 and the valve body 102 increases. The valve needle 110 can be lifted further from the position in Figure 2C until it reaches the fully open position. With a nozzle arrangement such as that shown in FIG. 2C , the maximum fuel mass flow rate may be limited by the limitation of the open area provided by the orifice 116 . If this is the case, raising the valve needle beyond the point where fuel flow is blocked by the orifice will not result in a further increase in fuel mass flow.

Referring now to Figures 2D and 2E, there are shown two different embodiments of cross-sectional views through the D/E cut-off line indicated in Figure 2A. Figures 2D and 2E illustrate that the constant flow region can be made in different shapes without departing from the spirit of the present disclosure. FIG. 2D shows a simple concentric circular arrangement that defines a constant flow area between the valve needle 110 and the valve body 201 . In FIG. 2E , the constant flow area is provided by a plurality of grooves formed in the valve body 102 . By way of example, the grooves are shown as having a bottom defined by a diameter concentric with the opposing wall of the valve body 110, and the shoulder 103 provides a raised surface between the grooves. Those of ordinary skill in the art will understand that the grooves and the raised surfaces between the grooves may take different shapes without departing from the scope of the present disclosure. Although FIGS. 2D and 2E are described with reference to the embodiment of FIG. 2A , these embodiments for the shape of the constant flow region can be applied to all embodiments disclosed herein. For some embodiments, grooves may be formed in the needle surface rather than the valve body surface.

Figure 3 shows another embodiment of a nozzle with an inwardly opening valve needle. Valve body 302 and valve needle 310 define the illustrated portion of fuel chamber 304 . Valve needle 310 is in a closed position in which it is forced into fluid-tight contact with valve seat 312 . When the valve needle 310 is lifted off the valve seat 312 in the direction of arrow 350 , the bore 316 provides an outlet for fuel to exit the valve body. The difference between this embodiment and that of FIGS. 2A to 2C is that the valve body 302 is provided with two shoulder regions 303 and 303A, both of which provide a vertical surface parallel to the vertical surface of the valve needle 310. . Shoulder 303 in Figure 3 is similar to shoulder 103 in Figures 2A to 2C. The shoulder 303A provides a second parallel surface area that provides a larger constant flow area when the vertical surface of the valve needle 310 is opposite the second parallel surface area. Thus, the nozzle arrangement of FIG. 3 may provide two ranges of valve needle motion in which fuel mass flow may be substantially constant. When the vertical surface of the valve needle 310 is opposite the vertical surface of the shoulder 303A, a lower substantially constant fuel mass flow is provided, and when the vertical surface of the valve needle 310 is opposite the vertical surface of the shoulder 303A, Provides a large, substantially constant fuel mass flow.

4A through 4C illustrate yet another embodiment of a valve body and needle arrangement that provides a substantially constant fuel mass flow for a predetermined range of needle motion. In FIG. 4A , valve needle 410 is shown in a closed position, seating against valve seat 412 such that fuel cannot flow through nozzle 414 . To initiate a fuel injection event, valve needle 410 may move in the direction of arrow 450 . For example, the valve needle shown in Figures 4 and 5 is known as an outwardly opening valve needle, the valve needle shown in Figures 4 and 5 can move off the valve seat and in a direction parallel to the direction of fuel flow, and use A fuel injection valve with an outwardly opening needle is sometimes called a mushroom valve. In FIG. 4B , the valve needle 410 has been lifted off the valve seat 412 to an open position within the needle range of motion in which a substantially constant fuel mass flow can be injected. In FIG. 4B , the portion of the vertical side of the valve needle 410 provided by the shoulder 403 is opposed to the vertical wall of the valve body 402 . The parallel and opposite vertical surfaces provide a gap, denoted d1, between them. Similar to the other embodiments, this gap is sized to provide a flow region that restricts fuel flow through the nozzle 414 to a substantially constant fuel mass flow rate for a range of needle motion as long as the valve needle 410 A part of the vertical side of the valve body 402 is opposite to the vertical wall provided. In FIG. 4C , the valve needle 410 has been lifted beyond the point where the shoulder 403 and the vertical surface of the valve body 402 face each other. Beyond this point, the flow area between the valve needle 410 and the valve body 402 increases as the valve needle 410 moves further away from the valve seat 412 . From the position in Figure 4C, the valve needle 410 can be lifted further in the direction of arrow 450 until it reaches the fully open position.

Figure 5 shows another embodiment of a nozzle arrangement with an outwardly opening valve needle. Valve body 502 and valve needle 510 define the illustrated portion of fuel chamber 504 . The valve needle 510 is in an open position in which it has been lifted from the closed position in the direction of arrow 550 . The difference between this embodiment and the embodiment of FIGS. 4A to 4C is that the valve needle 510 is provided with two shoulder regions 503 and 503A, both of which provide vertical alignment with the opening through the valve body 502. Vertical surfaces with parallel surfaces. The shoulder 503 in Figure 5 is similar to the shoulder 403 in Figures 4A-4C. The shoulder 503A provides a second parallel surface area that provides a larger constant flow area when the vertical surface through the opening of the valve body 502 is opposite the second parallel surface area. Accordingly, the nozzle arrangement of FIG. 5 may provide two ranges of valve needle motion in which fuel mass flow may be substantially constant. When the vertical surface of the shoulder 503A is opposite the vertical surface of the opening through the valve body 502, a lower substantially constant fuel mass flow is provided, and when the vertical surface of the shoulder 503A is opposite the opening through the valve body 502 When the vertical surfaces of the openings are opposed, a greater substantially constant fuel mass flow is provided. In the illustrated example, the difference in the constant flow region for the two needle ranges of motion is defined at least in part by the difference in dimensions d1 and d2. Those of ordinary skill in the art will appreciate that other embodiments can achieve the same result without departing from the spirit and scope of the present disclosure. For example, without increasing the gap size, the flow area can be increased by widening a slot such as that shown in Figure 2E, thereby increasing the constant flow area for the second needle range of motion.

FIG. 6 is a graph of fuel mass flow Q versus needle lift L. FIG. The curve shown by line 600 is representative of a conventional fuel injection valve. As shown by curve 600, for a conventional fuel injection valve, an increase in needle lift causes a gradual increase in fuel mass flow until a maximum fuel mass flow Qc is reached, for example, when the flow is blocked by a restriction provided by the nozzle hole, or by When blocked by another restriction provided elsewhere in the fuel injection valve. As the curve approaches the choke flow rate, the slope of the curve 600 becomes gentler, so small changes in lift do not significantly affect fuel mass flow when the valve needle is commanded near the fully open position.

For fuel injection valves that control needle lift to control fuel mass flow, with conventional fuel injection valves, if Qa represents the appropriate fuel mass flow for idle or low load conditions, then the valve needle is commanded to lift a distance L1, Thus providing a suitable flow rate. Due to the steep slope of curve 600 around lift L1 , even a small deviation from position L1 can lead to a significant change in the actual fuel mass flow.

The curve shown by solid line 610 is representative of a fuel injection valve using features of the present disclosure. For example, at idle or low load conditions, the valve needle may be commanded to a position at an intermediate point between L1 and L2. Because the slope of the curve 610 between L1 and L2 is much gentler than the slope of the curve 600 for the same range of valve needle movement, the operation of the fuel injection valve of the curve 610 has increased stability, thereby improving the internal combustion engine performance, efficiency And/or reduce the emission of harmful combustion products, such as particulate matter and nitrogen or carbon oxides, and/or reduce internal combustion engine noise. The embodiments shown in FIGS. 2 and 4 illustrate examples of fuel injection valves that can provide a range of needle movement in which fuel can be injected at a substantially constant fuel mass flow rate. The range of motion between L1 and L2 represents the range of motion of the needle corresponding to when the parallel vertical surfaces of the needle and the valve body cooperate with each other to define a gap of dimension d1. As the valve needle moves further away from the valve seat and beyond this range, the fuel mass flow gradually increases along a steeper slope until a maximum fuel mass flow is reached.

Dashed line 620 plots the flow characteristics of a fuel injection valve such as that shown in FIGS. 3 and 5 . These fuel injection valves offer two needle ranges of motion, wherein the fuel mass flow is substantially constant in both ranges of motion. The range of motion between L3 and L4 represents the range of motion of the needle corresponding to when the parallel vertical surfaces of the needle and the valve body cooperate with each other to define a gap of dimension d2. When the valve needle is lifted to a position between L3 and L4, there is little change from the commanded fuel mass flow Qb because the slope of the curve 620 is relatively flat.

7 is a graph of various embodiments of commanded mass flow versus time through a fuel injection valve for a single fuel injection event. Each of the commanded shapes shown may benefit from the stability that may be achieved using the disclosed nozzle and needle features to enhance flow characteristics through the fuel injection valve. In this illustration, Qc again represents the maximum fuel mass flow. Curve 710 corresponds to a relatively small fuel mass flow Qa, such as may be commanded for idle or low load conditions. An advantage has been described as being able to reduce the variability in the amount of fuel introduced into the internal combustion engine from cycle to cycle at idle and low load conditions. It is also suitable to introduce fuel directly into the combustion chamber of the internal combustion engine in a step-like waveform, wherein initially a lower fuel mass flow is injected, for example Qa or Qb in FIG. 7 , followed by a higher fuel mass flow , as shown by curve 730 . A fuel injection valve having two needle ranges of motion that provide a substantially constant fuel mass flow may use a controller programmed to use a waveform such as that shown by plot 710 for an idle state, and use the waveform shown by plot 720 The waveform is used for lightly loaded states, either in a stepped waveform starting with curve 710 until t2 and then after t2 with curve 720 , or after t2 for higher load states curve 730 can be selected. One of ordinary skill in the art will understand that other combinations are possible, such as starting with curve 720 until t2, followed by curve 730, so that even more fuel is injected into the internal combustion engine. In some operating states it may also be advantageous to provide a downward jump when the valve needle moves from the open position to the closed position. An advantage of a fuel injection valve of the disclosed character is that, at predetermined stages in the waveform used to control the movement of the valve needle, a constant flow region can be selected to provide a more stable mass flow of fuel, reducing cycling to Loop variability.

The disclosed fuel injection valve was developed for gaseous fuels, but the same features are also advantageous for fuel injection valves injecting liquid fuels. However, with liquid fuels, there are additional considerations that must be taken into account, such as cavitation and maintaining a suitable pressure for atomization of the fuel. Cavitation occurs when a sudden pressure drop drops the fuel pressure below the vaporization pressure and some fuel is vaporized before the fuel is expelled from the injection valve. Problems associated with cavitation and atomization can be avoided, for example, by using one or more of the following strategies: (i) introducing fuel into the fuel injection valve at an initial pressure high enough to ensure that the fuel pressure remains above gasification pressure, and suitably high after the restricted flow region to atomize the fuel as it exits the fuel injection valve; (ii) size the restricted flow region to limit the pressure drop so that the fuel pressure is not reduced to below the gasification pressure or minimum pressure required to atomize the fuel as it exits the fuel injection valve; (iii) provide smooth entry into restricted flow regions, thereby reducing turbulence that would cause low pressure regions; and (iv) utilize such The nozzle and needle are manufactured from materials that will not be damaged by exposure to conditions associated with cavitation. With liquid fuels, the disclosed features can be used and achieve many of the same advantages as can be achieved with gaseous fuels. For example, by reducing the variability of the total amount of fuel injected, more consistent performance and reduced engine noise can be achieved at idle and low load conditions.

While particular elements, embodiments and applications of the present invention have been shown and described, it should of course be considered that the invention is not limited thereto since particularly in light of the foregoing teachings without departing from the scope of the invention. , various modifications can be made by those skilled in the art.

Claims (39)

1. Fuelinjection nozzle that is used for fuel is introduced internal-combustion engine, described Fuelinjection nozzle comprises:

A. valve body comprises nozzle and the fuel cavity that is limited by described valve body;

B. needle, can in described nozzle, between operating position and full open position, move, flow to the described internal-combustion engine to allow described fuel to flow and pass described nozzle from described fuel cavity, wherein in described closed position, described needle is taken a seat near the valve seat that links to each other with described nozzle, at the full open position place, described needle and described valve seat spaced furthest; With

C. strain-type actuator, be used to activate described needle, described actuator can be operated described needle is remained on the place, neutral position between described operating position and the full open position, thereby to another injection events, valve needle lift can change in the injection events process and from an injection events; With

Wherein, when described needle near first neutral position of described operating position and and isolated second neutral position, described first neutral position between the time, the shape of described needle and described valve body is designed to provide ordinatedly the constant flow region between described needle and the described valve body, and flowing of described nozzle passed in wherein said constant flow region restriction, thereby mass flow rate is for certain range of valve needle movement substantially constant, the border of wherein said range of movement is limited by described first and second neutral positions, and wherein said constant flow region is arranged in the described fuel cavity of described valve seat upstream.

2. Fuelinjection nozzle as claimed in claim 1 is characterized in that, when described needle was between described first and second neutral positions, described constant flow region was less than the flow region of the opening between described valve seat and the described needle.

3. Fuelinjection nozzle as claimed in claim 1 is characterized in that, described constant flow region is the annular space between described needle and the described valve body.

4. Fuelinjection nozzle as claimed in claim 1 is characterized in that described strain-type actuator comprises transducer, and described transducer is selected from comprise group piezoelectricity, magnetostrictive and electrostrictive transducer.

5. Fuelinjection nozzle as claimed in claim 1, it is characterized in that, also comprise electronic controller, described controller can program control to send command signal to described actuator, thereby described needle is moved between described operating position and described full open position, and move to position between them according to predetermined waveform.

6. Fuelinjection nozzle as claimed in claim 1, it is characterized in that, also comprise amplifier, described amplifier is arranged between described actuator and the described valve element, is used to amplify the strain that produced by actuator to cause the bigger corresponding motion of described valve element.

7. Fuelinjection nozzle as claimed in claim 6 is characterized in that, described amplifier is the hydraulic displacement amplifier.

8. Fuelinjection nozzle as claimed in claim 6 is characterized in that described amplifier uses at least one bar.

9. Fuelinjection nozzle as claimed in claim 1 is characterized in that described fuel is introduced in the described fuel cavity with gaseous state.

10. Fuelinjection nozzle as claimed in claim 9 is characterized in that, described fuel is selected from the group that comprises following material: rock gas, methane, ethane, liquefied petroleum gas (LPG), lighter flammable hydrocarbon derivative, hydrogen and their mixture.

11. Fuelinjection nozzle as claimed in claim 1, it is characterized in that, described needle is the needle of inwardly opening, thus when from described operating position when move described enable possition, described needle can move along the inside direction opposite with the mobile direction of fuel.

12. Fuelinjection nozzle as claimed in claim 11 is characterized in that, described nozzle comprises the closed end with at least one hole, and when described needle and described valve base chamber separated, it is injected that described fuel can pass described hole.

13. Fuelinjection nozzle as claimed in claim 11, it is characterized in that, described nozzle comprises the closed end with a plurality of holes, when described needle and described valve base chamber separate, it is injected that described fuel can pass described a plurality of hole, and total open area in described a plurality of holes is greater than described constant flow region.

14. Fuelinjection nozzle as claimed in claim 13, it is characterized in that, when described needle was in described full open position, total open area in described a plurality of holes provided minimum restriction, thus and the mobile quality of fuel flow that passes described Fuelinjection nozzle of control.

15. Fuelinjection nozzle as claimed in claim 1, it is characterized in that, and isolated the 3rd neutral position, described second neutral position defines the border of second range of valve needle movement between the described second and the 3rd neutral position, and when described needle is between the described second and the 3rd neutral position, the shape of described valve body and described needle is designed to the flow region that provides constant ordinatedly, flowing of described nozzle passed in described flow region restriction, thereby the mass flow rate substantially constant still is higher than the mass flow rate when described needle is between described first and second neutral positions.

16. a Fuelinjection nozzle that is used for injecting fuel directly into the firing chamber of internal-combustion engine, described Fuelinjection nozzle comprises:

A. valve body comprises nozzle with outlet and the fuel cavity that is limited by described valve body, and described outlet can be arranged in the described firing chamber;

B. needle, can in described nozzle, between operating position and full open position, move, enter the described firing chamber to allow described fuel to flow and pass described jet expansion from described fuel cavity, in described closed position, described needle is taken a seat near the valve seat that links to each other with described nozzle, in described open position, described needle and described valve seat spaced furthest; With

C. strain-type actuator, be used to activate described needle, described actuator can be operated described needle is remained on the place, neutral position between described operating position and the full open position, thereby in injection events process neutralization from an injection events to another injection events, valve needle lift can change; With

Wherein, when described needle near first neutral position of described operating position and and isolated second neutral position, described first neutral position between the time, the shape of described needle and described valve body is designed to provide substantially invariable pressure to descend when described fuel flows ordinatedly when passing described nozzle, thereby mass flow rate is for certain range of valve needle movement substantially constant, the border of described range of movement is limited by described first and second neutral positions, the needle of wherein said form fit and valve body define the constant flow region between described needle and described valve body, and wherein said constant flow region is arranged in the described fuel cavity of described valve seat upstream.

17. Fuelinjection nozzle as claimed in claim 16 is characterized in that, described strain-type actuator comprises transducer, and described transducer is selected from comprise group piezoelectricity, magnetostrictive and electrostrictive transducer.

18. Fuelinjection nozzle as claimed in claim 16, it is characterized in that, also comprise electronic controller, described controller can program control to send command signal to described actuator, thereby described needle is moved between described operating position and described full open position, and move to position between them according to predetermined waveform.

19. Fuelinjection nozzle as claimed in claim 16, it is characterized in that, also comprise amplifier, described amplifier is arranged between described actuator and the described valve element, be used to amplify the strain that produces by actuator, to cause the bigger corresponding motion of described valve element.

20. Fuelinjection nozzle as claimed in claim 19 is characterized in that, described amplifier is the hydraulic displacement amplifier.

21. Fuelinjection nozzle as claimed in claim 19 is characterized in that, described amplifier uses at least one bar.

22. Fuelinjection nozzle as claimed in claim 16 is characterized in that, when fuel was injected in the described firing chamber, described fuel was in gaseous state.

23. Fuelinjection nozzle as claimed in claim 22 is characterized in that, described fuel is selected from the group that comprises following material: rock gas, methane, ethane, liquefied petroleum gas (LPG), lighter flammable hydrocarbon derivative, hydrogen and their mixture.

24. Fuelinjection nozzle as claimed in claim 16 is characterized in that, described needle is the needle of inwardly opening, thereby when when move described enable possition, described needle moves along the inside direction opposite with the mobile direction of fuel.

25. Fuelinjection nozzle as claimed in claim 24 is characterized in that, described nozzle comprises the closed end with at least one hole, and when described needle and described valve base chamber separated, it is injected that described fuel can pass described hole.

26. Fuelinjection nozzle as claimed in claim 16, it is characterized in that, and isolated the 3rd neutral position, described second neutral position limits the border of second range of valve needle movement between the described second and the 3rd neutral position, and when described needle is between the described second and the 3rd neutral position, the shape of described valve body and described needle is designed to provide substantially invariable pressure to descend when described fuel flows ordinatedly when passing described nozzle, thereby the mass flow rate substantially constant still is higher than the mass flow rate when described needle is between described first and second neutral positions.

27. the nozzle that Fuelinjection nozzle is passed in an adjusting enters the method for the fuel mass flow rates in the internal-combustion engine, described method comprises:

Utilize strain-type actuator directly to activate needle with the control valve needle lift, neutralize from an injection events to another injection events in the injection events process, described valve needle lift can change in response to the operation of internal combustion engine state of measuring, and described serviceability comprises engine load and rotating speed;

When the predetermined constant fuel mass flow rate of needs, the order needle moves to the position between first and second neutral positions, described first and second neutral positions are the predetermined positions between operating position and full open position, wherein said Fuelinjection nozzle is designed to when described needle is between described first and second neutral positions, and when the constant pressure of described fuel, allow constant fuel mass flow rates; With

When fuel mass flow rates that need be different with described predetermined constant fuel mass flow rates, order described needle move into place between described operating position and the full open position, but the position between described first and second neutral positions not, be designed to the form fit of wherein said needle and described valve body when described needle is between described first and second neutral positions, provide constant flow region, and wherein in described operating position, described needle is forced near valve seat, and described constant flow region is positioned at the upstream of described valve seat.

28. method as claimed in claim 27 is characterized in that, also comprises when the described substantially invariable mass flow rate of needs, orders described needle to the intermediate point between described first and second neutral positions.

29. method as claimed in claim 27 is characterized in that, described substantially invariable fuel mass flow rates is corresponding to the fuel mass flow rates that is fit to for idling or low load condition.

30. method as claimed in claim 27, it is characterized in that, described substantially invariable fuel mass flow rates is regulated by following method, promptly when described needle is between described first and second neutral positions, utilizes constant flow region to provide described nozzle interior flow restriction.

31. method as claimed in claim 27, it is characterized in that, described second neutral position is corresponding to the valve needle lift bigger than the valve needle lift in described first neutral position, and by described needle is moved towards the position of described complete opening from described second neutral position, described fuel mass flow rates can little by little increase.

32. method as claimed in claim 27, it is characterized in that, described second neutral position is corresponding to the valve needle lift bigger than the valve needle lift in described first neutral position, and described method also comprises when the needs second substantially invariable mass flow rate, with described needle order to position between described second neutral position and the 3rd neutral position, when described needle is between described first and second neutral positions, described Fuelinjection nozzle provides the flow region of first restriction, and when described needle is between the described second and the 3rd neutral position, the flow region of second restriction is provided, and the flow region of described second restriction is greater than the flow region of described first restriction.

33. method as claimed in claim 32 is characterized in that, by described needle is moved towards the position of described complete opening from described the 3rd neutral position, described fuel mass flow rates can little by little increase.

34. method as claimed in claim 27 is characterized in that, also comprises described fuel is directly injected to the firing chamber of described internal-combustion engine from described nozzle.

35. method as claimed in claim 27 is characterized in that, also comprises described fuel is introduced in the described nozzle with gaseous state.

36. method as claimed in claim 35 is characterized in that, described fuel is selected from the group that comprises following material: rock gas, methane, ethane, liquefied petroleum gas (LPG), lighter flammable hydrocarbon derivative, hydrogen and their mixture.

37. method as claimed in claim 27 is characterized in that, described strain-type actuator comprises transducer, and described transducer is selected from comprise group piezoelectricity, magnetostrictive and electrostrictive transducer.

38. method as claimed in claim 27, it is characterized in that, also comprise the control injection pulse width assisting to be controlled at the total amount of the fuel that sprays in the injection events process, thereby pulse width can change from an injection events to another injection events in response to the operation of internal combustion engine state of predetermined measurement.

39. method as claimed in claim 27, it is characterized in that, also comprise the control fueling injection pressure assisting to be controlled at the total amount of the fuel that sprays in the injection events process, thereby fueling injection pressure can change from an injection events to another injection events in response to the operation of internal combustion engine state of predetermined measurement.

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