KR20000024967A - Injection unit and method of feeding gas fuel to engine - Google Patents

Abstract

PURPOSE: An injection unit is provided to feed gas fuel to an engine as the changed flow of the fuel is delivered by a solenoid valve unit. CONSTITUTION: A gas fuel is fed to an engine by the steps of: producing the instantaneous working condition of an engine; deciding the instantaneous flow(Q) of fuel relevant to the instantaneous working condition; delivering the instantaneous flow of fuel to the engine; calculating the whole instantaneous delivery rate(C) to secure the instantaneous flow of fuel; and generating command signals to open at least one of solenoid valves to feed the instantaneous flow of fuel, based on the whole delivery rate.

Description

Injection unit and method for supplying gas fuel to the engine

The present invention relates to a fuel injection unit and method for supplying gaseous fuel to a propulsion engine.

As an alternative to the conventional fuel supply unit for supplying gaseous fuel to the engine, it is known to use an injection supply unit comprising an injector for supplying fuel directly to the intake port of the cylinder itself.

Such an injector is connected to the fuel tank by a mechanical control device. The control device acts to subdivide the required amount of fuel into each injector and has walls with openings through which each injector penetrates and becomes a flow path through which the fuel flows.

This control and subdivision device also has a translational mechanism shutter. This translational shutter is coupled with the wall to alternate along the wall by the action of an electric motor, usually a stepping motor, and adjusts the associated flow path according to the operating conditions of the engine.

Although the injection units of the type described above are widely used, they are not satisfactory in terms of functionality and do not supply the exact amount of fuel set for the particular operating state of the engine. In addition, in some cases, the response time to changes in the conditions under which the injection unit is operated becomes relatively long.

These problems have led to the need for a mechanical device for controlling and subdividing the flow rate of fuel. In fact, the flow rate of the fuel supplied by the unit varies with the clearance generated in the connecting device connecting the shutter to both the wall and the engine. In terms of constituents, it is almost impossible to reduce tolerances, despite rising costs, and in a typical fuel, various parts that control the sensitivity of the distributor to the amount of impurities that are substantially always present, although in different amounts. In this regard, no solution can be given to the problem of reducing the work tolerance.

In addition, the amount of fuel supplied by the control and subdivision apparatus is changed in accordance with the change in the temperature at which the injection unit is operated, and the conditions of the fuel are changed substantially as the temperature rises. The unit is subject to thermal expansion which makes precision fuel metering quite difficult.

As described above, the conventional injection unit is difficult to improve the performance of the engine because of the relatively long and changeable response time.

Accordingly, it is an object of the present invention to provide an injection method which can solve the above problems in a simple manner.

In order to achieve the above object of the present invention, the present invention provides a method for determining an instantaneous operating condition of an engine, determining an instantaneous value of a fuel flow amount required for the instantaneous operating condition, and supplying the instantaneous fuel flow amount to the engine. An injection method for supplying gas fuel to an engine, in particular a propulsion engine, comprising:

The supply of the instantaneous fuel flow rate is made by a solenoid valve assembly having respective delivery rates, calculating the value of the overall instantaneous delivery speed which ensures the required instantaneous fuel flow rate, and the overall delivery speed, i.e. Generating a control signal for opening the at least one solenoid valve to deliver a fuel flow rate.

Another object of the invention is to provide an injection unit for supplying gaseous fuel to an engine, in particular a propulsion engine.

In order to achieve the above object, the present invention provides a means for supplying gaseous fuel under a predetermined pressure, means for obtaining an instantaneous operating condition of an engine, processing means for determining an instantaneous fuel flow rate required for the instantaneous operating conditions, and the fuel. An injection unit for supplying gaseous fuel to an engine, in particular a propulsion engine, comprising means for sending a flow rate to the engine,

Said delivery means comprises a solenoid valve assembly having respective delivery speeds, at least a memory means for storing said delivery speeds, first processor means for calculating a value of an overall instantaneous delivery speed to ensure said necessary instantaneous fuel flow rate, and A unit for supplying gaseous fuel to an engine, in particular a propulsion engine, further comprising signal generating means for generating a control signal for opening the at least one solenoid valve to supply an overall delivery speed, ie an instantaneous fuel flow rate. do.

1 is a block diagram illustrating an injection unit according to an embodiment of the present invention.

FIG. 2 is a block diagram for explaining FIG. 1 in more detail.

3 is an enlarged cross-sectional view of the two components of FIG. 2 arranged at two different operating conditions.

4 is a flow chart illustrating a method of operation of the unit of FIG. 1 in accordance with the present invention.

* Description of the symbols for the main parts of the drawings *

2: engine 8: delivery unit

10: subdivision 11: injector

12: solenoid valve 13: casing

22: shutter 23: spring

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a gas injection system for supplying a gaseous fuel, preferably Liquefied Petroleum Gas (LPG) or methane gas, to the heated propulsion engine 2.

The gas injection system 1 comprises a pressure tank 3 for storing fuel, and an inlet connected to the tank 3 via a multi-valve unit 5 and an inlet connected to the tank 3 via a tube 6. It is provided with a pressure reducer 4 having an outlet connected to the inlet 7.

The delivery unit 8 changes the amount of fuel to an intake port (not shown) of each cylinder in accordance with the instantaneous operating conditions of the engine 2 (multi-point distribution; "multi-point" distribution).

To this end, as shown in FIG. 2, the delivery unit 8 is provided in the delivery device 9 for supplying the required flow rate, and in the direction in which fuel flows on the outlet side of the delivery device 9, and the delivery device ( And a subdivision 10 which is operated to distribute the flow rate of the fuel sent out by 9) in the same amount. The delivery unit 8 also includes an injector 11 coupled to each cylinder (not shown) of the engine 2. The injector 11 is coupled to the outlet of the subdivision 10 and sends fuel flow directly to the intake port of the coupled cylinder.

As shown in FIGS. 2 and 3, the delivery device 9 is a plurality of digital solenoid valves 12 (only four of which are shown in FIG. 2) connected in parallel to continuously deliver the overall fuel flow rate to the subdivision 10. ). The solenoid valve 12 is selected, regulated and controlled by binary logic to increase the flow cross sectional area and the delivery speed C which increase with the equality sequence below two. In other words, any one of the solenoid valves 12, in particular the solenoid valve 12 having the smallest flow cross-sectional area of the total solenoid valves 12 being used, has a reference delivery speed C * and the other solenoid valve 12 Has a larger flow cross-sectional area (eg 2C *, 4C *). In this case, when it is necessary to make the delivery speed equal to 5C * in order to deliver a given required fuel flow rate, a solenoid valve having a delivery speed of C * and 4C * in order to transfer the required amount of fuel ( It is sufficient to open 12 simultaneously.

As shown in FIG. 3, the feeding device 9 includes an outer casing 13. The outer casing 13 has a pupil 14 housing the solenoid valve 12, a fuel inlet 7 through which the fuel transferred through the tube 6 enters, and a plurality of outlets 15 (only two are shown in FIG. 3). Is formed. Each solenoid valve 12 has two engagement ends 16 which are coupled to the casing 13 by a very tight seal by interposing a number of sealing washers. A fuel inlet 18 is formed through the engaging end 16 of each solenoid valve 12 in communication with the inlet 7 and each outlet 19 in communication with each outlet 15. Each solenoid valve 12 has an engagement intermediate portion 20 that cooperates with the engagement end 16 to form a chamber 21 for receiving the shutter 22. Each shutter 22 is movable in chamber 21. The shutter 22 has a closed position for keeping the inlet 18 closed by a compression spring 23 received in the engagement intermediate portion 20, and an open position for communicating one inlet 18, 19 with the other inlet. To move between. The open position is held by the coil or magnet which is received in the pupil of the engagement intermediate portion 20 and acts in the opposite direction to the spring 23.

Referring again to FIG. 1, the sending unit 8 is provided with a command and control device 25 for controlling the sending device 9. The apparatus 25 also has an electronic central processing and control unit 26 having a first input to which the output of the calibration unit 27 is input. The calibration unit 27 is installed between the electronic central processing and control unit 26 and the memory block 28. The delivery speed of the solenoid valve 12 is stored in the electronic central processing and control unit 26 and the memory block 28, and the central injection electronic control unit 29 supplies liquid fuel (usually gasoline) to the engine 2. A mapping is stored that contains the relationship between the command sent to control to be sent normally and the flow rate Q of the gaseous fuel sent to the engine 2.

The output of the central control unit 29 is sent to the second input of the electronic central processing and control unit 26, the output of which is input to the element 30 controlling the solenoid valve 12.

Referring again to FIG. 2, the subdivision 10 includes one inlet 31 through which the total flow rate sent by all solenoid valves 12 is conveyed, a plurality of outlets connected to each injector 11, and It has a flow regulator 32 that equally regulates the flow rate of fuel passing through the other injector 11. The flow regulator 32 is connected to each injector 11 and has an orifice 33 having a flow cross section which is adjustable to the engine 2 and is adjustable in a continuous manner as a function of the required instantaneous flow rate.

The delivery unit 8 is operated according to an injection method for supplying gas fuel to the engine shown in the flowchart of FIG. 4. The method comprises the steps of obtaining 34 the instantaneous operating conditions of the engine 2, determining the required fuel flow rate Q corresponding to the obtained instantaneous operating conditions 35, and ensuring the required fuel flow rate Q. Calculating 36 the total delivery speed C as a function of fuel supply conditions. The injection method reads 37 and totally the solenoid valve 12 having the value of the reference delivery speed C * stored in the memory block 28 and in particular cases the smallest flow cross-sectional area of all the solenoid valves 12. Calculating 38 a value of T = C / C *, which is the ratio of the delivery speed C and the reference delivery speed C *. The method comprises the step 39 of detecting the integral value I of the ratio T of the delivery speed. If the integral value I is not zero, the first command signal (1) which causes one or more solenoid valves 12 to be in the open position and determines the total delivery speed Ci to be equal to the integral value I. S1) is generated (41), and when the integral value I becomes zero, the next step is not executed.

In parallel with the step of detecting the integral value I, the fractional part F of the delivery speed T is detected (42). Then, if the fractional part F becomes zero, it is stopped in the next step. Otherwise, the opening time t of the at least one solenoid valve 12 is calculated (45). Thereafter, a second command signal S2 for opening the solenoid valve 12 is generated 46 so that the delivery speed Cf is equal to the fractional part of the ratio T of the delivery speed (46). Conveniently, the second signal S2 has a predetermined predetermined period tc and has two rectified wires facing each other at predetermined intervals by the first opening time t calculated in each period. Portal type. While the engine 2 is operating, the first opening time t between the two rectifying wires varies between zero and a maximum value such as the period of the signal tc if the fractional part is equal to zero. Thus, by varying the ratio between the first opening time t and the period tc of the signal, a predetermined method is performed in a continuous manner between zero and the predetermined sending speed, using a resolution that depends on the resolution generating the command. The average delivery speed in the period which is changed by the solenoid valve which has a delivery speed can be calculated | required.

In this regard, the sum of the sending speeds corresponding to the generated two signals S1 and S2 provides the required total instantaneous sending speed.

As described above through the preferred embodiment of the present invention, the present invention by using the solenoid valve 12 assembly as described above, the injection unit 8 is improved performance than the conventional injection unit, any of the engine Even operating conditions have the advantage of being able to deliver very precise fuel flow rates, in particular flow rates exactly as calculated theoretically based on the instantaneous operating conditions of the engine 2.

Indeed, by using special control of the digital solenoid valve assembly 12 and solenoid valve 12, in particular, there are no mechanical members slidably cooperating with others, resulting in very fast response times, and the thermal experienced during operation. It is possible to achieve injection units insensitive to change.

Furthermore, as described above, since the injection unit uses a flow splitter 10 separate from the solenoid valve 12, as described above, the total flow rate theoretically required under any operating conditions of the engine 2. It is possible to supply a precise total flow rate that exactly matches the flow rate, and it is possible to subdivide the total flow rate into each of the several cylinders of the engine 2, and to control the flow of the instantaneous total flow rate regardless of the distribution of the instantaneous flow rate to each cylinder. Do. This complex function can be controlled to supply the correct amount of fuel to each cylinder, and can maintain the total amount of pollutants discharged from the engine 2 within a predetermined value set by the environmental pollution-related engine.

In particular, the solenoid valve 12 may be replaced with something different from that described in the embodiments of the present invention, and the solenoid control and command device 25 may be replaced with another type.

Further, the subdivision 10 for subdividing the fuel flow rate delivered by the solenoid valve 12 may be of a different type than that described in the embodiments of the present invention, in particular in a discontinuous manner as a function of the flow rate dispensed. It can be replaced with

Although the present invention has been described above using embodiments of the present invention, it will be apparent to those skilled in the art that various modifications may be made without departing from the spirit of the present invention.

Claims (17)

An engine, in particular a propulsion engine, comprising obtaining an instantaneous operating condition of an engine, determining an instantaneous fuel flow rate Q corresponding to the instantaneous operating condition, and sending the instantaneous fuel flow rate Q to the engine In the injection method for supplying gas fuel to The delivery of the instantaneous fuel flow rate Q is carried out by a solenoid valve assembly having respective delivery speeds, calculating the total instantaneous delivery speed C to ensure the required instantaneous fuel flow rate Q, and the total delivery speed. (C) providing command signals to open at least one of the solenoid valves to provide the instantaneous fuel flow rate (Q). The method of claim 1, wherein the ratio T of the total delivery speed C and the reference delivery speed C * is calculated, and the command signals are generated as a function of the delivery speed ratio T. Injection method for supplying gas fuel to the engine 3. The injection method of claim 2, wherein the reference delivery speed (C *) is the delivery speed of the solenoid valve having the smallest flow cross-sectional area among all the solenoid valves of the solenoid valve assembly. 4. The method of claim 2 or 3, wherein the command signal generating step comprises: detecting an integral value (I) of the ratio (T) of the delivery speed, sending out for at least one of the solenoid valves of the solenoid valve assembly; Generating a first open control signal S1 such that the speed Ci is equal to the integral value I, detecting the fractional part F of the ratio T of the delivery speed, and the delivery speed Cf Generating a second opening control signal (S2) for at least one first solenoid valve in such a manner as to determine) to be equal to the fractional part (F). Way. The method of claim 4, wherein the second signal (S2) has a predetermined predetermined period (tc) and two rectifying wires facing each other, the step of generating the second signal (S2) An injection method for supplying gaseous fuel to the engine, characterized in that it precedes the step of calculating the time t between the rectifying wires to obtain the relevant delivery speed Cf. A gas fuel source under a predetermined pressure, means for obtaining an instantaneous operating condition of the engine, calculation means for determining a required instantaneous fuel flow rate Q corresponding to the instantaneous operating condition, and sending the fuel flow rate to the engine An injection unit for supplying gaseous fuel to an engine, in particular a propulsion engine, comprising a delivery means, The delivery means comprises a solenoid valve assembly having respective delivery speeds, at least a memory means for storing the delivery speeds, a first processor for calculating a value of the total instantaneous delivery speeds to ensure the required instantaneous fuel flow rate Q. Means, further comprising means for opening at least one solenoid valve to generate control signals (S1, S2) for supplying a total delivery speed (C) and the required fuel flow rate (Q). Injection unit for supplying gas fuel. 7. The apparatus of claim 6, further comprising second processor means for calculating a ratio T of the total delivery speed C and the reference delivery speed C * stored in the memory means, wherein the control signal generating means comprises: An injection unit for supplying gaseous fuel to an engine, characterized by generating a control signal (S1, S2) as a function of the ratio T of said delivery speed. 8. The injection unit of claim 7, wherein the reference delivery speed (C *) is the delivery speed of the solenoid valve having the smallest flow cross-sectional area among all the solenoid valves of the solenoid valve assembly. The first detection means for detecting the integral value I of the ratio T of the delivery speed, and the value F of the fractional part of the ratio T of the delivery speed. And second control means for opening the at least one first solenoid valve of the solenoid valves in such a manner that the delivery speed Ci is equal to the integral value I. First generating means for generating a first opening signal S1 and a second for opening at least one second solenoid valve of the solenoid valves in such a manner that the delivery speed Cf is equal to the fractional part F; An injection unit for supplying gaseous fuel to the engine, characterized in that it further comprises a second generating means for generating an open signal (S2). 10. The apparatus according to claim 9, wherein the second generating means is operated to generate a second control signal S2 having two opposing rectifying wires and a predetermined constant period tc for each period, And a third processor means for calculating a time t between the two rectifying wires to obtain a delivery speed Cf. The injection unit according to any one of claims 6 to 10, wherein the solenoid valves are connected in parallel to each other. 12. The method of any one of claims 6 to 11, wherein at least some of the solenoid valves are adjusted to provide a delivery speed that is variable in accordance with a ratio of equal to two below. Injection unit. 13. The fuel cell according to any one of claims 6 to 12, further comprising: a plurality of injection members for delivering the fuel amount associated with each cylinder of the engine, and the injection member further comprises a subdivision for uniformly distributing the total instantaneous flow rate. Injection unit for supplying gas fuel to the engine comprising a. 14. The injection unit of claim 13, wherein the subdivision is separated from the solenoid valve. 15. The injection unit of claim 13 or 14, wherein said subdivision has a flow regulator coupled to said respective injection members. An injection method for supplying gaseous fuel to an engine, in particular a propulsion engine, described with reference to the accompanying drawings. An injection unit for supplying gaseous fuel to the engine, in particular the propulsion engine, described with reference to the accompanying drawings.