JP4806039B2 - Method for inspecting fluid fuel injection device for ignition - Google Patents

Description

  The present invention provides a plurality of supply devices for selectively supplying liquid and gaseous fuels to a combustion chamber, at least one ignition fluid fuel injection device for supplying ignition fluid fuel, and a cylinder of a multi-fuel engine The present invention relates to a method for inspecting an ignition fluid fuel injection device for a multi-fuel engine, comprising a measuring device for measuring an ignition process in the engine and an evaluation device for evaluating the ignition process measured by the measuring device.

  When operating a multi-fuel engine, a lean gas / air mixture is usually ignited by a small amount of ignition fluid fuel in the combustion chamber. The ignition fluid is injected into the combustion chamber, for example, immediately before the top dead center of the piston of the reciprocating piston machine by an appropriate supply system using an ignition fluid fuel injection device.

  Almost any configurable injection process is possible with known systems for supplying ignition fluid fuel with an injector into the combustion chamber of a reciprocating piston machine. Therefore, the injection start and the injection end of the ignition fluid fuel can be freely selected by the injection device. Furthermore, in many cases, the multi-fuel engine is equipped with an electronic engine control device, and the engine, such as the temperature, the output value, the combustion parameter, the rotation speed, the pressure, etc. of the fuel and exhaust gas, is provided by these electronic engine control devices. Operation data is continuously grasped.

  Damage or clogging of the injector due to combustion residues or undetected errors in the ignition fluid fuel supply can lead to a stop of ignition fluid fuel injection. If it occurs during gas operation, it will lead to a stop of combustion in the corresponding cylinder. When this happens, it leads to a reduction in engine output on the one hand, and on the other hand, an unburned gas / air mixture flows into the exhaust system, causing explosion if local boundary conditions in the exhaust system are disadvantageous. It can also cause. Therefore, stoppage of combustion during gas operation should be avoided. Therefore, preferably the functionality of the ignition fluid fuel injection can already be verified before switching to gas operation.

  Conventionally, it has been impossible to inspect an ignition fluid fuel injection device before switching a liquid fuel operation in progress in a multi-fuel engine to a gas operation. Conventionally, malfunction of an ignition fluid fuel injection device was recognized only when there was a decrease in engine output and smooth running during gas operation, or a decrease in exhaust gas temperature after the cylinder. In the past, identification of damaged or clogged igniting fluid fuel injectors has been based on visual inspections of individual cylinders or power measurements or operating behavior of individual cylinders.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for inspecting an ignition fluid fuel injection device so that the function inspection of the ignition fluid fuel injection device of a multi-fuel engine can be performed during liquid fuel operation.

  The above problem is solved by the method according to claim 1 of the present invention. The dependent claims contain preferred developments.

The method of the present invention includes the following steps.
a) operating the multi-fuel engine in liquid fuel operation, wherein at least one ignition fluid fuel injection device injects the ignition fluid fuel into the combustion chamber of one cylinder of the multi-fuel engine;
b) setting the injection time and / or ignition time of the one or more ignition fluid fuel injectors offset from the fuel ignition time;
c) evaluating the value of the ignition process measured by the measuring device;

  The method of the present invention is suitable for multi-fuel engines that can be operated with different liquid fuels as well as gaseous fuels. As the liquid fuel, a fuel that has a cetane number higher than 30 and is easily flammable and can be operated by the diesel principle is considered. Also suitable are liquid fuels that have a cetane number of less than 30 and are difficult to ignite and require additional devices such as spark plugs for ignition.

  A multi-fuel engine suitable for application of the method of the present invention can be switched from operation using liquid fuel to operation mode using a fuel / air mixture, which is preferably a lean, preferably gaseous fuel that is difficult to ignite. It is comprised so that. In the case of gaseous fuel, the method of the present invention can also be applied to an ignition fluid fuel injection device for igniting a lean liquid fuel / air mixture. As the combustion gas for such a multi-fuel engine, for example, natural gas, liquid gas, wood gas, biogas, landfill gas, underground explosive gas, hydrogen and the like can be used.

  Since the lean gas / air mixture supplied to the combustion chamber in gas operation or lean operation usually contains an excessive amount of excess air, ignition fluid fuel is injected into the combustion chamber for spark ignition. The gas / air mixture is ignited by the ignition energy. Liquid fuel suitable for this purpose is usually used as the ignition fluid fuel, and this liquid fuel is preferably used in liquid fuel operation of a multi-fuel engine.

  A multi-fuel engine suitable for carrying out the inspection method of the present invention includes a first supply device for supplying liquid fuel into the first combustion chamber. At this time, one cylinder of the multi-fuel engine has one or more combustion chambers. Hereinafter, the main combustion chamber of the cylinder is referred to as a first combustion chamber. The supply device may also be suitable for supplying different liquid fuels. The first supply device is preferably a pump device, a fuel pipe and a fuel mixture for supplying the fuel directly into the combustion chamber of a multi-fuel engine or a fuel mixture for supplying the mixture after liquid fuel mixture is created It is equipped with a production and supply device.

  A suitable multi-fuel engine further comprises a second supply device for supplying gaseous fuel to the combustion chamber of the engine, which is preferably a lean gas / air mixture. It is preferably configured so that the production takes place before supply to the combustion chamber.

  The multi-fuel engine further includes a third supply device for supplying ignition fluid fuel to the combustion chamber of the engine. The third supply device preferably includes one or more ignition fluid fuel injectors for each cylinder of the multi-fuel engine. At this time, the ignition fluid fuel injection device can be arranged so that the ignition fluid fuel is directly injected into the first combustion chamber of the cylinder of the multi-fuel engine. However, the ignition fluid fuel injection device can also be arranged in a second combustion chamber, for example a so-called precombustion chamber. The igniting fluid fuel is self-ignited in the combustion chamber or ignited using a suitable igniter. When the ignition fluid fuel injection device is disposed in the second combustion chamber of the cylinder, the ignition fluid fuel injection device has one or more connections to the first combustion chamber, and this connection Since the ignition energy is transmitted from the second combustion chamber to the first combustion chamber through the path, the gas / air mixture existing in the first combustion chamber is ignited. A plurality of ignition fluid fuel injection devices may be arranged in the second combustion chamber according to the configuration of the combustion chamber, and the first combustion chamber of the cylinder may be connected to the plurality of second combustion chambers. it can. In order to avoid clogging of the injection device during liquid fuel operation, the ignition fluid fuel injection device desirably supplies the ignition fluid fuel to the cylinder during both liquid fuel operation and gas operation. The method of the present invention is also suitable for an ignition fluid fuel injection device that is configured integrally with the injection device of the first supply device and can control injection independently of the injection function of the first supply device.

  The multi-fuel engine suitable for applying the inspection method of the present invention preferably further comprises one measuring device for measuring the characteristic value of fuel combustion in the cylinder, which characteristic value is preferably Are evaluated in an evaluation device which is part of engine control. It is also possible to use a measuring device and / or an evaluation device that is temporarily placed in the engine for the purpose of carrying out the inspection method. Combustion parameter monitoring helps to recognize early ignition of fuel, known as “knocking”, even in “normal operation”. For this purpose, for example, an acoustic knocking sensor is used to examine the signal for spectral content typical of knocking. In an engine equipped with a spark plug for fuel ignition, the spark plug can be used as an “ion sensor” between ignitions. By measuring the current at the DC voltage applied thereto, information on the pressure, temperature, and ion concentration in the combustion chamber can be obtained. At this time, the early ignition is recognized because the ion current peak is early. Furthermore, the pressure rise due to compression and ignition can be measured by measuring the pressure of the individual cylinders. It is also possible to grasp the deviation of the combustion process from the change in combustion noise heard by the human ear.

  In carrying out the method of the invention, the engine is operated with liquid fuel. As already mentioned, the ignition fluid fuel injector to be tested preferably operates in liquid fuel operation. This inspection method can be carried out regardless of the load on the engine operation during the inspection period.

  According to one embodiment of the invention, in the inspection process, the ignition start of the ignition fluid fuel injector is set off the liquid fuel ignition time, which is usually just before the top dead center of the piston. At this time, the injection start and ignition timing of the ignition oil are shifted after or preferably before the ignition timing of the liquid fuel. The ignition fluid fuel and the interval provided between the fuel injection time or the ignition time are selected so that ignition of the ignition fluid fuel can be measured by the measuring device.

  When the ignition fluid fuel to be used is easily ignited, in early injection, the injection is preferably performed when the ignition fluid already injected in the cylinder is ignited without using external ignition assistance. To be done. This is the case, for example, when the air present in the cylinder is already sufficiently heated by the compression that has taken place, or the element that stimulates ignition has a sufficient temperature.

  When ignition fluid fuels are used that are not easily ignited and are therefore ignited using a suitable device such as a spark plug, the ignition fluid fuel injection and ignition timing is preferably set in an appropriate manner. The

  In the case of the delayed injection start, the ignition fluid fuel is injected during the fuel combustion process. In this case, the ignition fluid fuel is immediately ignited, and this can be grasped by the measuring device because, for example, a further pressure increase occurs.

  When the start of injection of the ignition fluid fuel is deviated from the time of fuel ignition, the measuring device measures an ignition process different from the liquid fuel operation other than the inspection method. The pre-ignition process then proceeds analogously to knocking ignition, so that, for example, acoustically or similar to delayed ignition fluid fuel ignition, or by changes in the pressure change process in the cylinder, or ionic current measurement or similar measurement Can be measured by the method and is preferably recognized as early ignition by a suitable evaluation device.

  If too much or too little ignition fluid fuel is pumped into the combustion chamber by the ignition fluid fuel injector due to malfunction, too much or too little change in the ignition process is measured by the measuring device. For example, if the ignited fluid fuel injection device that has been inspected has stopped, so that the ignited fluid fuel is not supplied into the combustion chamber, the ignition process will not change. Therefore, it is possible to inspect the functionality of the ignition fluid fuel injection device before operating the gas operation of the multi-fuel engine.

  When a plurality of ignition fluid fuel injectors are arranged in one cylinder, the functional tests of the individual ignition fluid fuel injectors are preferably performed one after the other. Rather than measuring the ignition process of individual cylinders with a measuring device arranged in a multi-fuel engine, it is also desirable if, for example, the combustion noise or high-frequency vibration parts of a multi-fuel engine are monitored acoustically. Done.

  The evaluation device performs an evaluation of the ignition process measured by the measuring device, and preferably does not function by assigning which of the tested ignition fluid fuel injectors the measured ignition corresponds to The ignition fluid fuel injection device is limited. If the evaluation results obtained by the inspection method of the present invention indicate that combustion failure or no combustion will occur at all due to a malfunction of the ignition fluid fuel injection device, switch to gas operation of a multi-fuel engine. It can be avoided.

  It is further possible, for example, not to inject only some of the individual cylinders of a multi-fuel engine by knowing the ignition fluid fuel injection device that does not function or does not function properly based on the evaluation results. When a plurality of ignition fluid fuel injection devices are arranged in one cylinder, the adjustment of the injection time and / or the injection amount of these ignition fluid fuel injection devices is performed by the ignition of the air / gas mixture. To be done steadily. Also, the inspection result supports the planning and execution of necessary maintenance means.

It is a figure of a multi-fuel engine suitable for applying the inspection method of the present invention. It is the graph which showed the example of the change of the cylinder pressure in the cylinder in normal driving | operation, and the change of an acoustic spectrum. It is the graph which showed the example of the change of the cylinder pressure in a cylinder when the injection start and ignition time have shifted | deviated from the fuel ignition time.

  Further advantages, features and applicability of the present invention are described below with reference to the figures.

  FIG. 1 illustrates elements of a multi-fuel engine suitable for applying the inspection method of the present invention. The engine shown in the figure is provided with a cylinder 2 having a cylinder head 3 and constructed in a known manner. In the cylinder 2, the piston 4 guided by the connecting rod 5 moves.

  A fuel injection device 6 is attached to the cylinder head 3, and by this fuel injection device 6, liquid fuel can be directly injected into the first combustion chamber 9 from the fuel pump 8 through the fuel pipe 7. The fuel injection device 6, the fuel pipe 7, and the fuel pump 8 are elements of a first supply device for supplying liquid fuel into the first combustion chamber 9. The cylinder head 3 is provided with a second combustion chamber 11 in addition to the fuel injection device 6, and the second combustion chamber 1 is connected to the first combustion chamber 9 via one or more communication ducts 12. ing. An ignition fluid fuel injection device 13 is disposed in the second combustion chamber 11, and the ignition fluid fuel injection device 13 is ignited by an ignition fluid fuel pump 16 via an ignition fluid fuel pipe 14. Fluid fuel is supplied. The pressure in the ignition fluid fuel pipe 14 of the third supply device is provided by the ignition fluid fuel pump 16.

  The intake / exhaust exchange in the combustion chamber of the engine is performed by a known method via the intake valve and the exhaust valve (17, 18). In the embodiment of this figure, the gas / air mixture is produced at a place other than the combustion chamber. This involves the elements of the second supply device, including the mixture generation unit 20 and the gas supply line 21.

  In the inspection method, the ignition fluid fuel injection device 13 is set to start the injection before the ignition time, which is also applied to engine operation during the inspection period, and is connected to the evaluation device 25 during the execution of the inspection method. The ignition process in the cylinder 2 is measured by the sensor 26, and the measured value is sent to the evaluation device 25.

  The upper graph in FIG. 2 shows the pressure rise in the cylinder 2 during the crankshaft rotation of the multi-fuel engine during normal operation. The lower graph of FIG. 2 shows the acoustic spectrum of the combustion. The illustrated combustion cycle is for liquid fuel operation, and the point of injection of the ignition fluid fuel injector 13 is selected so that the ignition fluid fuel ignites simultaneously with the liquid fuel mixture. As an example at this time, a uniform pressure rise in the cylinder 2 is illustrated from the top dead center of the piston 4 (0 ° KW (0 ° crankshaft)) to fuel / air mixture ignition and subsequent expansion. . Combustion noise is almost limited to the ignition timing.

  The upper graph of FIG. 3 shows the pressure increase in the cylinder 2 during the rotation of the crankshaft of the multi-fuel engine during the execution of the inspection method of the present invention. FIG. 3 shows two possibilities when the injection start setting or the ignition timing of the ignition fluid fuel injection device 13 is shifted. As in the case of FIG. 2, the lower graph shows the acoustic spectrum of the combustion during the inspection method for the possibilities of the two embodiments.

  When the inspection method of the present invention is performed, a pressure change as illustrated in the cylinder 2 appears. During execution of the inspection method, in the liquid fuel operation, the injection timing of the ignition fluid fuel is shifted to the early position 30 or the delay position 35. The response to such a deviation in the injection time point is inspected by the evaluation device 25 during the inspection period.

  In the case of the early injection start 30 of the ignition fluid fuel injection device 13, an increase in pressure is already observed before the high pressure phase compared to the combustion cycle in which the injection start of the ignition fluid fuel injection device 13 is normal. The combustion process that appears at this time is also recognized by the high frequency pressure fluctuations typical of knocking. An example of the spectrum at this time is shown in the lower graph.

  In the case of the delayed injection start 35 of the ignition fluid fuel injection device 13, one more pressure increase is seen compared to the combustion cycle in which the injection start of the ignition fluid fuel injection device 13 is normal. The combustion process that appears at this time is also recognized by the high frequency pressure fluctuation typical of knocking, and this pressure fluctuation example is shown in the graph below.

  In the evaluation of the signal obtained from the sensor 26 during the execution of the inspection method, it is examined whether the pressure measured in the cylinder 2 has a typical change, for example the change shown in FIG. If, for example, an acoustic knocking sensor is used as sensor 26, the measured signal has a spectral content typical of time-shifted ignition as shown in the lower graph of FIG. It is checked whether there is any. If such a pressure change or typical spectral content is recognized, it indicates that the ignition fluid fuel injector is functional. On the other hand, if the signal obtained from the sensor 26 does not include a signal indicating a “deviation” of the combustion change, it is concluded from the inspection result that the ignition fluid fuel injection device 13 has failed. It is done. The data determined in the evaluation device 25 is also used to define the defective ignition fluid fuel injection device 13.

2 cylinder 3 cylinder head 4 piston 5 connecting rod 6 fuel injection device 7 fuel pipe 8 fuel pump 9 first combustion chamber 11 second combustion chamber 12 connecting duct 13 fluid fuel injection device for ignition 14 ignition fluid pipe 16 ignition fluid pump 17 Intake valve 18 Exhaust valve 20 Mixture creation unit 21 Gas supply pipe 25 Evaluation device 26 Temperature sensor 30 Early injection start 35 Delayed injection start

Claims (16)

A first supply device for supplying liquid fuel to the first combustion chamber (9) of the cylinder (2);
A second supply device for supplying gaseous fuel to the first combustion chamber (9) of the cylinder (2);
At least one ignition fluid fuel injection device (13) for supplying ignition fluid to the first combustion chamber (9) or the second combustion chamber (11) communicating with the first combustion chamber (9). A third supply device comprising
A measuring device (26) for measuring the ignition process in the cylinder (2) of a multi-fuel engine, and an evaluation device (25) for evaluating the ignition process measured by the measuring device (26);
A method for inspecting an ignition fluid fuel injection device for a multi-fuel engine comprising:
a) The multi-fuel engine is operated in a liquid fuel operation in which ignition fluid fuel is injected into the first or second combustion chamber (9, 11) by at least one ignition fluid fuel injection device (13). And steps to
b) setting the injection start and / or ignition time of one or more of the ignition fluid fuel injectors (13) offset from the fuel ignition time;
c) evaluating the ignition process measured by the measuring device (26);
A method for testing an ignition fluid fuel injector for a multi-fuel engine.   2. The multi-fuel engine according to claim 1, wherein an injection start and / or ignition time of the one or more ignition fluid fuel injection devices is set before the fuel ignition time. Method for injecting fluid fuel for ignition.   2. The multi-fuel engine according to claim 1, wherein an injection start and / or ignition time of the one or more ignition fluid fuel injectors (13) is set after the fuel ignition time. 3. A method for inspecting a fluid fuel injection device for ignition.   4. In step b), the ignition fluid fuel is injected if the ignition fluid fuel self-ignites in the combustion chamber (9, 11). 4. The method for inspecting an ignition fluid fuel for a multi-fuel engine according to the item.   The method for inspecting a fuel injection device for an ignition fluid fuel of a multi-fuel engine according to any one of claims 1 to 4, wherein the multi-fuel engine is operated by a diesel system in a liquid fuel operation.   6. The method for inspecting a fluid fuel for igniting a multi-fuel engine according to claim 1, wherein diesel fuel is used as fuel in the liquid fuel operation.   4. The method for inspecting an ignition fluid fuel for a multi-fuel engine according to any one of claims 1 to 3, wherein the ignition fluid fuel is ignited by an ignition device in step b).   8. The fuel fluid injection device for ignition of a multi-fuel engine according to any one of claims 1 to 7, characterized in that fuel during liquid fuel operation is used as ignition fluid fuel during gas operation. Inspection method.   The second combustion chamber (11) is configured as a precombustion chamber of the first combustion chamber (9) and is connected to the first combustion chamber (9). 9. The method for inspecting a fluid fuel for ignition of a multi-fuel engine according to any one of claims 8 to 10.   An ignition fluid fuel injection device (13) of the third supply device for supplying the ignition fluid fuel to the first or second combustion chamber (9, 11) is an injection device (13) of the first supply device. 6) The method for inspecting a fuel fuel injection device for ignition of a multi-fuel engine according to any one of claims 1 to 9, characterized in that it is integrated with 6).   11. The measuring device (26) and / or the evaluation device (25) are arranged in an engine for carrying out this inspection method, according to any one of the preceding claims. A method for inspecting a fuel injection device for ignition of a multi-fuel engine.   12. The measuring device (26) according to any one of the preceding claims, characterized in that the measuring device (26) is suitable for recognizing a deviation in the ignition process in the combustion chamber (9, 11). A method for inspecting an injection device for fluid fuel for ignition of a multi-fuel engine. Said measuring device (26) is acoustically value, electrical value, characterized in that it can measure the pressure value, according to claim 12, injection device inspecting method of the ignition fluid fuel multi-fuel engine.   In step b), the ignition fluid fuel and the fuel injection time or the interval between the ignition time points are set so that ignition measurement of ignition fluid by the measuring device is possible. 14. The method of inspecting a fuel fuel injection device for ignition of a multi-fuel engine according to any one of 1 to 13.   15. The fuel fluid injection device for ignition of a multi-fuel engine according to any one of claims 1 to 14, characterized in that the individual fuel injection devices (13) for ignition are inspected one after another. Inspection method. A multi-fuel engine comprising an inspection device for carrying out the method according to any one of claims 1 to 13, wherein the engine is
A first supply device for supplying liquid fuel to the first combustion chamber (9) of the cylinder (2);
A second supply device for supplying gas fuel to the first combustion chamber (9) of the cylinder (2);
At least one ignition fluid fuel injector for supplying ignition fluid fuel to the first combustion chamber (9) or the second combustion chamber (11) connected to the first combustion chamber (9). 13) a third supply device comprising
A measuring device (26) for measuring the ignition process in the cylinder (2) of a multi-fuel engine;
A multi-fuel engine comprising an evaluation device (25) for evaluating an ignition process measured by the measurement device (26).

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