Method for operating gas injector
By continuously increasing the current of the electromagnetic actuator under the re-blowing of the gas injector, it ensures that sufficient opening force can be provided at high combustion chamber pressure, solving the problem of increased closing force during re-blowing, and achieving a smaller electromagnetic actuator design and more efficient fuel injection.
Patent Information
- Application Number
- CN202380066172.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-09-14
- Filing Date
- 2023-06-29
- Publication Date
- 2025-04-25
AI Technical Summary
In the case of re-blowing of the internal combustion engine, the combustion chamber pressure of the gas injector increases, causing the gas injector to overcome greater closing force when re-blowing, resulting in the electromagnetic actuator design requiring a larger size to provide sufficient magnetic force, thereby occupying more installation space.
By continuously increasing the current of the electromagnetic actuator until the end of the lifting phase and maintaining the current level during the pulling phase, ensuring that the electromagnetic actuator can provide sufficient opening force at high combustion chamber pressure.
It is realized that the gas injector can be effectively opened and kept in the open state under re-blowing situation, avoiding the waste of installation space caused by the increase in combustion chamber pressure, while reducing the size and manufacturing cost of the electromagnetic actuator.
Smart Images
Figure CN119895135A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for operating a gas injector of an internal combustion engine during re-injection after the main injection of the gas injector. Background Art
[0002] Gas injectors are known from the prior art in different configurations. The problem in gas injectors that inject gaseous fuel is that re-injection should be possible in order to reduce exhaust emissions and to reduce fuel demand. In particular, when the load point of the internal combustion engine changes under the condition of increased speed, re-injection should be performed in order to achieve a fast response, in particular a fast response of the turbocharger. In gas injectors that inject directly, the problem in the case of re-injection is the increased combustion chamber pressure, because the re-injection usually takes place shortly after reaching the top dead center of the internal combustion engine. Therefore, the increased combustion chamber pressure provides an additional closing force acting on the gas injector, which must be overcome additionally when re-injection is performed. In this regard, the magnetic circuit of the electromagnetic actuator of the gas injector has been designed so far that sufficient magnetic force exists even in the case of re-injection. However, this leads to a large electromagnetic actuator, which occupies a large installation space, which is larger than the installation space required for the actual operation of the injector. Summary of the invention
[0003] In comparison, the method according to the invention for operating an outwardly opening gas injector of an internal combustion engine during re-injection into the combustion chamber of the internal combustion engine, having the features of claim 1, has the following advantages: the electromagnetic actuator for the gas injector can be designed to be significantly smaller. As a result, installation space at the gas injector can be saved, which is particularly advantageous in gas injectors that are directly injected, because there is less installation space available for the gas injector near the combustion chamber of the internal combustion engine. In addition, due to the reduced electromagnetic actuator, the gas injector can be manufactured more cost-effectively. According to the invention, this is achieved in the following way: in the case of re-injection following the main injection of gaseous fuel into the combustion chamber, an improved control of the gas injector is performed. In this case, especially in the case of a constant high voltage level of the electromagnetic actuator, in a first step, in the boost phase (Boost phase), the electromagnetic actuator is controlled in such a way that the current for the electromagnetic actuator is continuously increased until the end of the boost phase. In another step, in the pull-in phase following the boost phase, the current for the electromagnetic actuator is kept constant. Here, the constant maintenance of the current is performed at a level corresponding to the maximum current intensity in the boost phase. As a result, despite the high combustion chamber pressure in the gas injector shortly after top dead center of the internal combustion engine, the gas injector can be opened and kept open during reinjection of the gas injector, because the increased actuator force compensates for the reduced gas pressure during reinjection of the gas injector.
[0004] Therefore, in the case of re-injection, in the pull-in phase, the current level can be increased in order to provide the force requirement of the electromagnetic actuator that is necessary in the case of re-injection. Here, the force requirement for opening the gas injector in the case of re-injection of the electromagnetic actuator must overcome the restoring force of the restoring spring and the combustion chamber pressure, wherein the electromagnetic actuator is supported by the system pressure of the gaseous fuel to be injected into the gas injector. In other words, the force required by the electromagnetic actuator for opening in the case of re-injection must be greater than the sum of the restoring force of the spring and the combustion chamber pressure minus the system pressure in the gas injector.
[0005] The dependent claims reveal preferred developments of the invention.
[0006] Preferably, the same or higher current level is present in the boost phase of the reblowing than in the main blowing, wherein the increased current demand in the pull-in phase of the reblowing is provided in particular by a boost capacitor and / or a DC-DC converter. Preferably, the boost current duration of the reblowing is the same or longer than in the main blowing. Thus, preferably, a higher pull-in current level is achieved in the case of the reblowing than in the main blowing. Preferably, the increased current demand in the pull-in phase is provided by a DC-DC converter and / or a boost capacitor. The boost capacitor is already charged in the normal operation of the internal combustion engine and is therefore able to provide the increased current demand in the case of the reblowing.
[0007] It is further preferred that the duration of the pull-in phase is shortened in the case of a re-blowing compared to the main blowing of the gas injector. This is possible because in the pull-in phase the current level remains at the increased pull-in current for a longer period of time.
[0008] Preferably, the duration of the pull-in phase of the reinsufflation is prolonged compared to the main insufflation of the gas injector.
[0009] It is further preferred that the current level in the ramp-up phase is increased during the re-blow-in compared to the main blow-in of the gas injector. Thus, at the end of the ramp-in phase, a higher current level is reached compared to the main blow-in of the gas injector, whereby the current level in the pull-in phase can also be kept at a higher level in the case of re-blow-in compared to the main blow-in in a simple manner.
[0010] Alternatively, in the case of reblowing, the current level in the boost phase remains the same compared to the main blow-in of the gas injector. A higher current level in the pull-in phase in the case of reblowing is then provided, for example, by using a boost capacitor.
[0011] Further preferably, the duration of the boost phase is extended in the case of reblowing compared to the main blow-in of the gas injector. Thus, more time is available for reaching a higher absolute current level in the boost phase in the case of reblowing compared to the main blow-in.
[0012] In order to be able to inject as much gaseous fuel as possible into the combustion chamber during the reinjection of the gas injector, the holding phase in which the gas injector remains open during the reinjection of the gas injector is preferably prolonged compared to the main injection of the gas injector.
[0013] Preferably, the holding current level in the holding phase of the reinsufflation of the gas injector, in which the gas injector remains open, is the same or higher than in the main blowing of the gas injector.
[0014] Preferably, a blow-in cycle of the internal combustion engine comprises only one main blow-in and one re-blow-in. That is to say, the blow-in cycle does not comprise a pre-blow-in.
[0015] Further preferably, the method according to the invention is used when the load point of the internal combustion engine is changed and in particular when the speed of the internal combustion engine is increased.
[0016] Further preferably, the reinjection takes place only after the top dead center of the piston of the internal combustion engine has been reached.
[0017] Furthermore, the invention relates to a control unit which is configured to carry out the steps of the method according to the invention.
[0018] Furthermore, the invention relates to a computer program having a program code which executes the steps of the method according to the invention when the computer program is run on a computer or a corresponding processing unit, for example a control unit according to the invention.
[0019] Furthermore, a computer program product is proposed which comprises a computer program according to the invention, which is stored on a machine-readable data carrier or storage medium. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The present invention will be described in detail below with reference to the accompanying drawings. In the accompanying drawings:
[0021] Figure 1 shows a schematic diagram showing the time-dependent voltage and current of an electromagnetic actuator according to the invention and the time-dependent force curve of the armature of the electromagnetic actuator during main injection of an internal combustion engine,
[0022] Figure 2 A schematic diagram is shown which shows the time-dependent voltage and current of the electromagnetic actuator according to the invention and the time-dependent force curve of the armature of the electromagnetic actuator during re-injection of an internal combustion engine, and
[0023] Figure 3 A longitudinal section through a gas injector which is provided for carrying out the method according to the invention is shown. DETAILED DESCRIPTION
[0024] Below, refer to Figures 1 to 3 A preferred embodiment of the present invention is described in detail.
[0025] Figure 3A gas injector 1 with an electromagnetic actuator is shown by way of example. The electromagnetic actuator comprises an electromagnetic coil 3 for acting on an axially movable armature 2. The armature 2 can come into contact with a closing element 4, in particular a valve needle, in order to release the blowing cross section at a sealing seat 5. Reference numeral 8 denotes a reset element of the gas injector. The closing element 4 is held in place by means of a valve spring 7. Figure 3 in the closed position shown in .
[0026] If the electromagnetic coil 3 is energized, a magnetic field is generated, the magnetic force of which moves the armature 2 in the direction of the closing element 4 (arrow 11). Here, the armature pin 9 connected to the armature 2 abuts against the closing element 4, so that the closing element 4 opens at the sealing seat 5 against the spring force of the valve spring 7. Here, the armature 2 moves as far as the travel stop 6 for the armature, which represents the fully opened state of the gas injector.
[0027] To close the gas injector 1, the current supply to the electromagnetic coil 3 is terminated so that the reset element 8 resets the armature 2 to the position in which it is positioned. Figure 3 At the same time, the valve spring 7 also resets the closing element 4 to the initial position shown in FIG. Figure 1 in the closed position shown in .
[0028] The gas injector 1 is an injector which opens outwards.
[0029] It is preferable to use hydrogen, methane or the like as the gaseous fuel.
[0030] Figure 1 The graph in FIG. 1 shows the main injection of a gas injector 1, which is used to inject gaseous fuel, especially hydrogen, directly into the combustion chamber of an internal combustion engine. Here, the gas injector and the electromagnetic actuator basically go through four phases, namely the lifting phase A, the pull-in phase B, the holding phase C and the closing phase D.
[0031] Here, in Figure 1 and Figure 2 In FIG. 1 , four curves are shown that change with time t in these four stages. Here, K1 shows the current change process of the current for the electromagnetic actuator over time. K2 shows the voltage of the electromagnetic actuator over time. K3 shows the force change process of the armature over time, and K4 shows the stroke of the armature over time t.
[0032] In addition, Figure 1 and Figure 2 Also shown in FIG. 5 is the closing force K5, which represents the sum of the spring force of the valve spring and the reaction force generated by the combustion chamber pressure. Figure 1 In the case of main blowing, the closing force is at F1, Figure 2In the reinjection shown in FIG, the closing force is increased by F' to F2, because in the case of reinjection carried out after the piston has reached top dead center in an injection cycle of the internal combustion engine, a high pressure is additionally present in the combustion chamber, and an opening force must additionally be provided to counteract this high pressure in order to open the gas injector.
[0033] In addition, Figure 1 and Figure 2 Also plotted in FIG. 5 is the battery voltage K6 , which is constant both in the case of reblowing and in the case of mainblowing.
[0034] like Figure 1 As shown, in the case of main injection of the internal combustion engine, the lifting phase A ends after time t1, the pull-in phase B ends after time t2, the holding phase C ends after time t3, and the closing phase D ends after time t4.
[0035] In addition, Figure 1 In the case of the main blow-in in the current curve K1 changes so that the current level drops at the end of the pull-in phase and then remains at a constant level I1 during the pull-in phase. Figure 1 As further shown, during the transition between the lifting phase A and the closing phase B, the opening process begins, i.e. the closing element begins to lift from the sealing seat. Here, in the closing phase B, the maximum opening stroke (stroke curve K4) is reached.
[0036] exist Figure 2 In the case of a re-injection of the gas injector after the main injection of the internal combustion engine has been completed, the current curve K1 changes so that in the boost phase A' the current increases continuously up to the point I1'. In the case of re-injection, this current value I1' is maintained throughout the pull-in phase B'. Figure 1 and Figure 2 As shown in the comparison between the two, the current level in the pull-in phase B' in the case of re-blowing is significantly higher than that in the case of main blowing. Figure 1 In this case, the current level in the pickup phase B' is preferably not as Figure 1 In the pull-in phase B, the voltage is adjusted not by the battery voltage, but by the boost voltage.
[0037] In particular, in the case of a re-blowing of the gas injector, the current level does not drop in the pull-in phase B'. At the end of the boost phase, the absolute value I1' is also greater than the value I1 in the case of a main blow-in. This can be achieved by dimensioning the DC-DC converter and / or the boost capacitor. The DC-DC converter and the boost capacitor are dimensioned so that during the positive main blow-in ( Figure 1) can cope with all relevant operating points of the gas injector. In the case of re-injection of the internal combustion engine, there is a power reserve which is sufficient for the necessary injection in the case of re-injection.
[0038] Therefore, energy reserves from the DC-DC converter and / or boost capacitors are used to Figure 2 The control for increasing the current level shown in Figure 2 ) in the curve K1 in the pull-in phase B'.
[0039] As Figure 1 and Figure 2 The comparison between the two further shows that the pull-in phase B'(t2'-t1') in the case of re-blowing is shorter than the pull-in phase B(t2-t1) in the case of main blowing. On the contrary, the boost phase A' in the case of re-blowing is longer than the boost phase in the case of main blowing due to the higher boost current level I1'. Figure 2 This is shown in FIG. 1 by comparing the time t1 ′ with the time t1 in the case of the main insufflation.
[0040] Due to the higher current level I1' in the case of reinjection, an increased opening force of the electromagnetic actuator is also provided, which can be achieved by Figure 1 and Figure 2 A comparison of the force profile K3 between the two is shown. As a result, the missing force component for opening the gas injector due to the high combustion chamber pressure in the gas injector can be compensated in the case of re-injection. In the holding phases C, C' and closing phases D, D' in the case of re-injection and main injection, all four curves K1, K2, K3 and K4 are again identical. However, the holding current level in the holding phase C' can be increased if necessary to compensate for the Figure 2 The increased closing force K5 in .
[0041] Thus, by regulating the pull-in current with a boosted voltage in the pull-in phase B', a higher average voltage can be achieved, and thus also a higher pull-in current I1' for the reinjection. Thus, a higher magnetic force can be generated by the electromagnetic actuator, which enables the gas injector to be opened at high combustion chamber pressures.
[0042] In the described embodiment, an actuation variant with an increased boost current at the end of the boost phase A' is shown. However, other actuation variants are also conceivable, in which the current profile in the boost phase A' in the case of re-blowing is the same as in the case of main blowing, and then compensation is only achieved by magnetic forces in the pull-in phase B' with increased current.
Claims
1. A method for operating an outwardly opening gas injector of an internal combustion engine, the gas injector injecting gaseous fuel and having an electromagnetic actuator for actuating the gas injector, wherein: In the case of a re-injection, in which the gaseous fuel is injected into the combustion chamber after the main injection, the following steps are carried out: The electromagnetic actuator is controlled in the lifting phase (A') so that the current (I) for the electromagnetic actuator is continuously increased until the lifting phase (A') ends, and In the pull-in phase (B') of the electromagnetic actuator, the current (I) is kept constant at a level corresponding to the maximum current intensity in the lifting phase (A') in order to compensate for the increased back pressure in the combustion chamber during the reinjection of the gas injector by the increased actuator force of the electromagnetic actuator.
2. The method according to claim 1, wherein: In the boost phase (A') of the reinjection, the same or higher current level is present than in the main injection, and the increased current requirement, in particular in the pull-in phase (B') of the reinjection, is provided by a boost capacitor and / or a DC-DC converter.
3. The method according to any one of the preceding claims, wherein: Compared to the main blowing of the gas injector, the duration of the pull-in phase (B′) of the reinjection is shortened.
4. The method according to any one of the preceding claims, wherein: Compared to the main blowing of the gas injector, the duration of the pull-in phase (B′) of the reinjection is prolonged.
5. The method according to any one of the preceding claims, wherein: Compared to the main blowing of the gas injector, the current level is increased in the ramp-up phase (A') of the reinjection.
6. The method according to any one of claims 1 to 4, wherein: The current level in the ramp-up phase (A') of the reinjection remains the same compared to the main injection of the gas injector.
7. The method according to any one of the preceding claims, wherein: Compared to the main blowing of the gas injector, the duration of the ramp-up phase (A′) of the reinjection is prolonged.
8. The method according to any one of the preceding claims, wherein: Compared to the main blowing of the gas injector, the holding phase (C′) of the re-blowing of the gas injector, during which the gas injector remains open, is prolonged.
9. The method according to any one of the preceding claims, wherein: Compared to the main blowing of the gas injector, the holding current level in the holding phase (C′) of the re-blowing of the gas injector, in which the gas injector remains open, is the same or higher.
10. A controller configured to carry out the steps of the method according to one of the preceding claims. 11 . A computer program having a program code which executes the steps of the method according to claim 1 when the computer program is run on a computer or a corresponding computing unit, such as a control unit. 12 . A computer program product having a computer program according to claim 11 , which is stored on a machine-readable data carrier or storage medium.