KR101927785B1 - Method for collecting 1 cycle data for output measurement and combustion analysis of large-sized low-speed 4 stroke engine - Google Patents

Abstract

A one-cycle data acquisition method for power measurement and combustion analysis of a large low-speed four-stroke engine according to an embodiment of the present invention includes: a step of collecting combustion pressure data for 1.5 cycles using a pulse signal of a predetermined angle sensor as a start signal; a step of determining a data collection range corresponding to one-cycle by comparing the combustion pressure data collected from the collected combustion pressure data for the 1.5 cycles with a preset reference pressure; and collecting the combustion pressure data from a data collection range corresponding to the determined one-cycle.

Description

TECHNICAL FIELD [0001] The present invention relates to a single-cycle data acquisition method and a single-cycle data acquisition method for output measurement and combustion analysis of a large-scale low-speed four-

The present invention relates to a one-cycle data collection method for output measurement and combustion analysis of a large-sized low-speed four-stroke engine, and more particularly, to a large-scale low-speed four-stroke engine capable of collecting data for one cycle of a large- To a one-cycle data collection method for output measurement and combustion analysis of an engine.

In general, ship engine monitoring devices are becoming essential equipment for maintenance of ship engine. Especially, in order to precisely and accurately measure the engine of the ship engine monitoring apparatus, a technique for minimizing the measurement error is indispensably required, and various measurement techniques have been developed for this purpose.

As the measurement technology of the ship engine monitoring device, there is a paper pressure measuring device for measuring the output of the ship engine. Such a paper pressure measuring device is a mechanical type and an electronic type.

Mechanical pressure gauges have been widely used in existing vessels. They are mounted on a test cock of an engine, and the pressure of the combustion chamber is measured on paper and its area is calculated by a measurer called a planimeter. However, in the case of a mechanical pressure gauge, there is a problem that an error of about 10% occurs between the state of the actual engine and the measurement result due to the skill of the person measuring and the error of the measurer.

Therefore, in recent years, electronic pressure measuring instruments supplemented with disadvantages of mechanical pressure measuring instruments have been mainly used.

Unlike a mechanical pressure gauge, the electronic pressure gauge measures the output of the ship's engine by automatically calculating the area of the volume by sampling the pressure during one cycle of the engine through digital equipment.

However, the above-mentioned acupressure meter is mainly optimized for measuring the output of a large low-speed two-stroke engine, which makes it difficult to measure the output of a large low-speed four-stroke engine.

In other words, conventionally, no separate measuring device has been developed for measuring the combustion state and output of a large low-speed four-stroke engine, and the state of the engine must be diagnosed by using a Pmax gauge or various thermometers and pressure gauges mounted on the engine side There is a problem that the combustion state and the output of the accurate engine can not be measured.

On the other hand, four cycles of suction, compression, explosion (expansion) and exhaust are performed during two revolutions of the crankshaft in one cycle of the large low-speed four-stroke engine. Therefore, one cycle means one cycle from the start of the suction stroke to the start of the suction stroke after performing compression, explosion, and exhaust stroke. During this cycle, two TDCs (Top Dead Center) come in, and two TDCs are called intake / exhaust TDC and compressed TDC (compression / explosion TDC).

Therefore, in collecting data by attaching an angle sensor, the large low-speed two-stroke engine is able to collect data for one cycle because the TDC and BDC (bottom dead center) are determined according to the explosion order when the Z pulse is set in the reference cylinder, In the low-speed four-stroke engine, since the Z pulse of the angle sensor occurs twice in collecting data of one cycle, it is difficult to find the reference Z pulse and it is difficult to constantly collect data constantly.

In addition, it is important to collect data of one cycle for precise output and combustion analysis. Especially, accurate data collection is important because TDC error 1 causes 10% of output error.

Korean Patent Publication No. 10-2015-0064837

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a large low-speed four-stroke engine capable of obtaining accurate one-cycle data, And to provide a one-cycle data collection method for output measurement and combustion analysis of a stroke engine.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to solve the above problems, a one-cycle data collection method for output measurement and combustion analysis of a large low-speed four-stroke engine according to an embodiment of the present invention includes a one-cycle data collection method for output measurement and combustion analysis of a large- Collecting combustion pressure data for 1.5 cycles with a pulse signal of a predetermined angle sensor as a start signal; Determining a data collection range corresponding to one cycle by comparing the combustion pressure data collected first among the collected combustion pressure data for the 1.5 cycles with a preset reference pressure; And collecting the combustion pressure data from a data collection range corresponding to the determined one cycle.

Wherein the step of comparing the first collected combustion pressure data among the combustion pressure data collected for the 1.5 cycles with the predetermined reference pressure to determine a data collection range includes the steps of, when the initially collected combustion pressure data is less than the reference pressure, A position from the position at which the combustion pressure data is first collected to one cycle is determined as the data collection range, and when the initially collected combustion pressure data is equal to or higher than the reference pressure, a position from a position where 0.5 cycles elapses to 1.5 cycles The data collection range can be determined.

According to an embodiment of the present invention, by obtaining accurate one-cycle data for a large low-speed four-stroke engine, accurate combustion analysis and output measurement of the engine may be possible.

In addition, since one cycle data of the large-sized low-speed four-stroke engine can be obtained through various methods such as compression TDC, Z pulse setting of the angle sensor, initial detection pressure comparison, etc., Thereby improving the reliability of the operation.

In addition, it is possible to acquire one cycle data of a large-sized low-speed four-stroke engine in a relatively simple manner compared with the conventional one, thereby improving convenience and workability of the operator, Costs can be saved by excluding the use of other equipment.

In addition, by providing accurate one-cycle data of a large-sized low-speed four-stroke engine, it is possible to perform an output measurement and a combustion analysis of the engine, thereby enabling the ignition timing and injection timing, fuel injection amount, The post combustion and the turbocharger matching relationship can be grasped precisely. Further, a solution for optimal combustion can be provided to selectively adjust the fuel injection timing, fuel injection amount, and turbocharger matching as necessary, Life and fuel consumption efficiency can be improved.

FIG. 1 is a flowchart showing a method of collecting one cycle data for output measurement and combustion analysis of a large-sized low-speed four-stroke engine according to an embodiment of the present invention.
Fig. 2 is a graph showing the compression pressures of the crankshaft with respect to the reference cylinder at respective rotation angles. Fig.
Fig. 3 (a) is a graph showing the pressure fluctuation rate of the reference cylinder with respect to the rotational angle of the crankshaft, and Fig. 3 (b) is an enlarged view of the portion "A" of Fig.
Fig. 4 is a diagram showing a line diagram of Fig. 2 and Fig. 3 (a) arranged on the basis of the rotation angle of the crankshaft.
5 is a flowchart illustrating a method of collecting one cycle data for output measurement and combustion analysis of a large low-speed four-stroke engine according to another embodiment of the present invention.
6 (a) is a view showing pulses of the angle sensor, and Fig. 6 (b) is a table showing the resolution and crank angle of the angle sensor.
7 (a) is a graph showing the combustion pressure for each crankshaft rotation angle when the compression TDC is detected for one cycle first, and FIG. 7 (b) Of the crankshaft.
FIGS. 8 and 9 are flowcharts illustrating one cycle data acquisition method for power measurement and combustion analysis of a large low-speed four-stroke engine according to another embodiment of the present invention.
10 (a) is a graph showing the combustion pressure for each crankshaft rotation angle when the intake / exhaust TDC is first detected for 1.5 cycles, and FIG. 10 (b) Of the crankshaft.
11 is a view showing measurement results produced by a combustion analysis apparatus of a large-scale low-speed four-stroke engine performing combustion analysis of a large-low-speed four-stroke engine.

Various embodiments will now be described in detail with reference to the accompanying drawings. The embodiments described herein can be variously modified. Specific embodiments are described in the drawings and may be described in detail in the detailed description. It should be understood, however, that the specific embodiments disclosed in the accompanying drawings are intended only to facilitate understanding of various embodiments. Accordingly, it is to be understood that the technical idea is not limited by the specific embodiments disclosed in the accompanying drawings, but includes all equivalents or alternatives falling within the spirit and scope of the invention.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but such elements are not limited to the above terms. The above terms are used only for the purpose of distinguishing one component from another.

In this specification, the terms "comprises" or "having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

In the meantime, "module" or "part" for components used in the present specification performs at least one function or operation. Also, "module" or "part" may perform functions or operations by hardware, software, or a combination of hardware and software. Also, a plurality of "modules" or a plurality of "parts ", other than a" module "or" part ", to be performed in a specific hardware or performed in at least one processor may be integrated into at least one module. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In addition, in the following description of the present invention, if it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted or omitted.

A one-cycle data collection method (hereinafter referred to as "one-cycle data collection method") for output measurement and combustion analysis of a large-sized low-speed four-stroke engine according to an embodiment of the present invention includes one cycle Cycle data acquisition method capable of collecting data during a one-cycle low-speed four-stroke engine, wherein the one-cycle data acquisition method includes a combustion analysis apparatus (not shown) capable of performing combustion analysis and output measurement of a large- Lt; / RTI >

The combustion analysis apparatus (not shown) may include a plurality of sensor units.

The plurality of sensor units may include a pressure sensor for detecting a signal regarding the individual compression pressure and the combustion pressure of each cylinder, and an angle sensor for detecting a signal relating to a rotation angle of the crankshaft.

The pressure sensor is installed in a test cock (not shown) of the engine E / G to detect the individual combustion pressure of each cylinder provided in the engine. The pressure sensor is electrically connected to a combustion analysis unit, which will be described later, and can transmit a signal relating to the individual combustion pressure of the detected cylinder to the combustion analysis unit.

The angle sensor may be installed at an end of the crankshaft of the engine to detect a rotation angle of the crankshaft, and may be electrically connected to the combustion analysis unit to transmit a signal relating to the rotation angle of the crankshaft detected to the combustion analysis unit. However, the angle sensor is not necessarily limited to being installed at the end of the crankshaft of the engine, but may be installed in a rotating body (e.g., a camshaft or the like) that rotates at a certain ratio with respect to the crankshaft together with the crankshaft. Further, the angle sensor can be installed on the flywheel side of the engine when a large low-speed four-stroke engine is used as an engine for a generator, and on the side opposite to the flywheel of the engine when a large low- speed four- Then, the Z pulse (signal for generating a pulse once per rotation) of the angle sensor can be matched with the actual TDC of the preset reference cylinder. Here, the reference cylinder may refer to the first cylinder connected to the crankshaft and causing the first explosion when the engine is driven. In actual TDC, when measuring a piston with a dial gauge, it may mean the center point between the moment when the piston reaches the position of the top dead point and the movement of the dial gauge stops and the moment the movement of the dial gauge starts again . For reference, the actual TDC is marked on the flywheel of the engine. For example, the angle sensor can be applied to an encoder having a preset resolution.

Meanwhile, an AD converter (not shown) may be further provided between the plurality of sensors and the combustion analysis unit to convert the analog signal transferred from each sensor into a digital signal.

Further, the present combustion analysis apparatus may include a combustion analysis section.

The combustion analysis unit is electrically connected to the plurality of sensors, receives a signal relating to the individual combustion pressure of each cylinder detected from each sensor and a signal relating to the rotation angle of the crankshaft, It is possible to collect the combustion pressure by the rotation angle of the crankshaft relative to the cylinder.

The combustion analyzing unit analyzes the combustion chamber volume and the pressure fluctuation rate for each cylinder by substituting the collected data into a preset formula, and calculates the combustion pressure of each cylinder based on the combustion pressure of the crankshaft at each rotation angle, And can be represented by a plurality of graphs relating to the pressure and the rate of pressure change by the angle of rotation of the crankshaft with respect to each cylinder.

Hereinafter, the analysis items and the diagrams analyzed through the combustion analysis unit will be described in more detail.

11 is a view showing measurement results produced by a combustion analysis apparatus of a large-scale low-speed four-stroke engine performing combustion analysis of a large-low-speed four-stroke engine.

Referring to FIG. 11, the combustion analyzing unit may trigger the A or B pulse signal of the angle sensor for measuring the rotation angle of the crankshaft, and calculate a combustion pressure of each cylinder during one cycle of the engine by the rotational angle of the crankshaft Which can be represented by the P? Line representing the rotational angle of the crankshaft for each cylinder on the X axis and the combustion pressure according to the rotational angle on the Y axis. For reference, the crankshaft can be set to rotate at an angle of 360 degrees per one cycle of the engine.

The combustion analyzing unit may calculate the combustion chamber volume for each cylinder by the rotation angle of the crankshaft using a preset formula, and express the combustion chamber volume for each cylinder by the PV diagram representing the combustion pressure for each cylinder volume. For reference, the volume of the combustion chamber, that is, the area in the PV diagram, may mean the output of the cylinder (city horsepower). Thus, the total sum of the outputs of each cylinder can mean the output of the engine.

The combustion analysis unit may calculate the pressure fluctuation rate of each cylinder with respect to the rotational angle of the crankshaft and may represent the pressure fluctuation rate of the crankshaft with respect to the rotational angle of the crankshaft with respect to each cylinder.

That is, the combustion analyzing unit differentiates the combustion pressure value for each cylinder with respect to the rotation angle of the crankshaft using a predetermined formula to identify a minute pressure change that is difficult to confirm on the P? .

Meanwhile, the combustion analyzing unit analyzes the heat generation rate and the combustion gas temperature for each cylinder by substituting the data collected from each sensor unit into a preset formula, and calculates the heat generation rate for each cylinder by the rotation angle of the crankshaft, The combustion gas temperature can be expressed by a plurality of diagrams relating to the combustion gas temperature by the rotation angle of the crankshaft.

More specifically, the combustion analysis unit calculates a heat generation rate for each cylinder by the rotation angle of the crankshaft for each cylinder using a preset formula, and expresses the heat generation rate by the rotation angle of the crankshaft for each cylinder as a heat generation rate diagram have.

Then, the combustion analysis unit calculates the combustion gas temperature for each cylinder with respect to the rotation angle of the crankshaft using a preset formula, and expresses the combustion gas temperature for each cylinder by the combustion gas temperature diagram showing the combustion gas temperature for each cylinder with respect to the rotation angle of the crankshaft .

That is, since the combustion process occurring in the combustion chamber occurs in a very short time, existing thermometers have a limitation in measuring the temperature of the combustion gas in the combustion chamber. Therefore, the combustion analysis unit can calculate the combustion gas temperature by the rotation angle of the crankshaft using the ideal gas state equation.

In addition, the combustion analysis unit can analyze at least two of the generated plurality of diagrams to determine the combustion state of the engine.

More specifically, the combustion analyzing unit analyzes at least two of the plurality of graphs and calculates a fuel consumption amount of each cylinder, a fuel injection state of each cylinder, a fuel consumption state of each cylinder, a fuel amount state of each cylinder, It is possible to determine the combustion state of the engine with respect to at least one of the knocking state, the post-combustion state of each cylinder, and whether or not the combustion maximum pressure among the cylinders coincides with each other.

Further, the combustion analysis unit may further display a table including at least one analysis data together with a plurality of diagrams.

11, the combustion analysis unit measures the output of the engine and then outputs the measured result to the engine rpm, the compression maximum pressure Pcomp, the maximum combustion pressure Pmax, the maximum combustion pressure Indicated Mean Effective Pressure (IMEP), Indicated Horse Power (IHP), Brake Horse Power (BHP), Rate Of Heat Release (ROHR), and Fuel Consumption And Specific Fuel Consumption (SFC).

Hereinafter, a 1-cycle data collection method according to an embodiment of the present invention will be described.

For the sake of simplicity, the same reference numerals are used for explaining the combustion analysis apparatus described above, and the same or redundant description is omitted. .

First, a one-cycle data collection method according to the first embodiment of the present invention will be described.

FIG. 1 is a flowchart showing a method of collecting one cycle data for output measurement and combustion analysis of a large-sized low-speed four-stroke engine according to an embodiment of the present invention, FIG. 2 is a graph showing a relationship between a compression pressure per rotation angle of a crankshaft Fig. 3 (a) is a graph showing the pressure fluctuation rate of the crankshaft with respect to the reference cylinder at a rotation angle, FIG. 3 (b) is an enlarged view of the "A" Fig. 4 is a diagram showing a line diagram of Fig. 2 and Fig. 3 (a) arranged on the basis of the rotation angle of the crankshaft.

Referring to FIG. 1, the combustion analysis apparatus cuts off the fuel of a predetermined reference cylinder, collects the compression pressure data from the reference cylinder, and generates a diagram relating to the compression pressure of the reference cylinder with respect to the rotation angle of the crankshaft (S110) .

More specifically, the combustion analysis apparatus cuts off the fuel of the preset reference cylinder, collects data on the infinitely detected compression pressure from the angle sensor mounted at the end of the reference cylinder crankshaft without any setting, And generates a diagram of the crankshaft's compression pressure for each rotation angle. Thus, as shown in FIG. 2, the combustion analysis apparatus can confirm the line indicating the angle of the crankshaft on the X axis and the Y axis representing the digital value before switching to the pressure value. 2, the cylinder pressure in the Y-axis represents the digital value of the compression pressure compressed only by air.

Here, the combustion analysis apparatus can remove the noise of the collected data in order to find an accurate point. For example, the combustion analysis apparatus can construct a high / low pass filter circuit to remove noise or perform a smoothing process through a separate post-processing program.

Next, the combustion analysis apparatus differentiates the compression pressure data collected from the reference cylinder with respect to the rotation angle of the crankshaft as shown in FIG. 3 (a), and then calculates the pressure change rate (S120).

Next, the combustion analysis apparatus detects the position of the compression TDC from the diagram relating to the pressure fluctuation rate by the rotation angle of the crankshaft relative to the reference cylinder as shown in Fig. 3 (b), and corresponds to the position of the detected compression TDC The rotation angle value of the crankshaft is stored (S130).

More specifically, the combustion analysis apparatus finds the position of the maximum point (Pcomp) of the compression pressure, that is, the point at which dp / d? = 0, from the diagram relating to the pressure fluctuation rate by the rotation angle of the crankshaft relative to the reference cylinder, And stores the rotation angle value of the corresponding crankshaft. For example, referring to FIGS. 3 (a) and 3 (b), it can be seen that the compression TDC of the reference cylinder is located at 186.6 degrees. That is, this means that the positional relationship between the Z pulse of the angle sensor and the compression TDC is 186.6 degrees. For reference, a large low-speed four-stroke engine can ignore the loss angle and therefore be identical to the actual TDC.

On the other hand, the combustion analysis apparatus detects the position of the compression TDC, stores the rotation angle value of the crankshaft corresponding to the position of the detected compression TDC, and then calculates the angle value of the crankshaft corresponding to the position of the compression TDC as an offset ). More specifically, the combustion analyzer can measure the angular value of the crankshaft corresponding to the position of the compression TDC, and then offset the number of decimal places of the measured angular value by offsetting it. For example, the compression TDC of the reference cylinder shown in FIG. 3 (b) can be stored at 186.6 to 187 degrees through the offset of the combustion analysis apparatus described above.

Next, the combustion analysis apparatus determines the start position of the intake / exhaust TDC by adding the rotation angle value of the crankshaft corresponding to 0.5 cycle to the rotation angle value of the crankshaft corresponding to the position of the compression TDC (S140).

That is, the rotation angle value of the crankshaft corresponding to the position of the compression TDC is set to the reference point 0, and the rotation angle value of the crankshaft, which is switched from the compression TDC to the intake / exhaust TDC, 360 are added to determine the start position of the intake / exhaust TDC. Here, in the case of the large low-speed four-stroke engine, since it is set to rotate at an angle of 720 degrees per cycle, 0.5 cycles means 360 degrees.

3 (b) and FIG. 4, the combustion analysis apparatus calculates the crankshaft rotation angle value 360 corresponding to the position of the crankshaft corresponding to the position of the compression TDC set to 0 And determines the added position as the start position of the intake / exhaust TDC. That is, the combustion analysis apparatus determines the starting position of the intake / exhaust TDC as the starting signal of the A pulse of the angle sensor and the position of 547 degrees which is the starting point of data acquisition.

Next, the combustion analysis apparatus acquires the compression pressure of the crankshaft with respect to the reference cylinder for one cycle from the start position of the intake / exhaust TDC (S150).

More specifically, after determining the starting position of the TDC, the combustion analyzing apparatus corrects the angle value of the starting position of the determined TDC again through the offset value, and then the starting position of the corrected TDC is set to 0, (720 degrees) according to the resolution of the crankshaft.

For reference, other cylinders other than the reference cylinder determine the position of the TDC according to the explosion order, so that the TDC can be determined by inputting the explosion order. For example, in the case of six cylinders, the explosion order may be determined at intervals of 120 degrees according to the order of 1-5-3-6-2-4.

Thus, the process of setting the Z pulse signal of the encoder to the reference cylinder can be eliminated, thereby allowing quick and accurate data collection for one cycle.

Next, a one-cycle data collection method according to a second embodiment of the present invention will be described.

FIG. 5 is a flowchart showing a method of collecting one cycle data for output measurement and combustion analysis of a large-sized low-speed four-stroke engine according to another embodiment of the present invention, FIG. 6 (a) FIG. 6 (b) is a table showing the resolution and the crank angle of the angle sensor. 7 (a) is a graph showing the combustion pressure for each crankshaft rotation angle when the compression TDC is first detected for one cycle, and Fig. 7 (b) The combustion pressure of the crankshaft according to the rotation angle of the crankshaft.

Referring to FIG. 5, the operator places the TDC of the preset reference cylinder in the TDC marker of the flywheel, and matches the Z pulse signal of the angle sensor with the TDC of the reference cylinder (S210). 6A, the A and B pulses of the angle sensor represent the resolution of the encoder and can be used as a trigger signal when collecting data. The trigger signal may be a crank angle. That is, FIG. 6B shows the resolution of the angle sensor (encoder), the angle display between the triggers converted thereto, and the number of data to complete one cycle. Therefore, dividing the 360 degrees by the resolution gives the angular interval of the crankshaft relative to the trigger signal, which can be the angle at which the crankshaft moves.

For example, when the Z pulse signal of the angle sensor is set to generate one signal per rotation, when the Z pulse signal of the angle sensor becomes the rising edge, that is, 5 V, the control device (not shown) ), So that the operator can confirm whether or not the Z pulse signal of the angle sensor matches the TDC of the reference cylinder. .

Next, the operator collects the combustion pressure data for one cycle using the Z pulse signal of the angle sensor as the start signal and the A or B pulse signal of the angle sensor as the trigger signal through the combustion analyzer (S220).

That is, the Z pulse of the angle sensor is set to the TDC of the first cylinder (reference cylinder), and the combustion pressure data for one cycle is collected using the A pulse or the B pulse of the angle sensor as the trigger signal. Here, since the B pulse signal of the angle sensor has a rising edge after 90 占 20, the offset value can be set to 0.25 when used as a trigger. The rising edge of each pulse signal is used as a reference of the start signal and the trigger signal, and the falling edge can be used as a reference.

Therefore, the combustion analysis apparatus can collect the data collected by the above method with the diagrams of FIGS. 7 (a) and 7 (b), and sequentially collect the data to collect one cycle data. For example, a plurality of lines arranged through the combustion analysis device may be arranged such that the intake / exhaust TDC comes first and the middle compression / explosion TDC comes.

Next, a one-cycle data collection method according to the third embodiment of the present invention will be described.

FIG. 8 is a flowchart illustrating a method of collecting one cycle data for output measurement and combustion analysis of a large low-speed four-stroke engine according to another embodiment of the present invention.

Referring to FIG. 8, the combustion analysis apparatus sets the Z-pulse signal of the angle sensor, which is generated during rotation of the crankshaft, to be 0 and 1 sequentially for one cycle (S310).

More specifically, the combustion analyzing apparatus calculates a zero pulse signal of the angle sensor generated in the first TDC of two TDCs detected from the angle sensor when the crankshaft is rotated, and a zero pulse signal of the angle sensor generated in the second TDC of the two TDCs Z pulse signal is set to "1". Therefore, the signals detected from the angle sensor are repeated infinitely with 0 and 1, and one of the two TDCs is a compressed TDC and the other is an intake / exhaust TDC.

Next, the combustion analysis apparatus collects the combustion pressure data for one cycle and determines the TDC of the signal generation point from the collected data (S320).

More specifically, the combustion analysis apparatus compares the combustion pressure data collected from the combustion pressure data collected for the first cycle with the preset reference pressure to determine the TDC of the signal generation point as the compression TDC or the intake / exhaust TDC . For example, when the initially collected combustion pressure data is equal to or higher than the reference pressure, the combustion analysis apparatus can determine the TDC of the signal generation point as a compression TDC. Herein, the preset reference pressure means a reference pressure for distinguishing the desired pressure from the compressed pressure. In most engines, the desired pressure is less than 5 bar, and the compression pressure according to the compression ratio of the diesel engine is generally more than 20 bar, The value of this pressure becomes the reference pressure for separating the intake / exhaust TDC and the compression TDC. That is, an engine using a Miller cycle exhibits a higher value of the desired pressure, so that the reference pressure can be adjusted according to the desired pressure. Therefore, in order to reduce the error, the average value of 5 to 10 pieces of the combustion pressure data collected for the first time is calculated. If the average value is 5 bar or less, the TDC can be determined as the reference TDC . The range of the reference pressure can be adjusted according to the setting of the turbocharger and the compression ratio.

Next, the combustion analysis apparatus acquires combustion pressure data for one cycle from the set position by maintaining or changing the signal setting of the angle sensor according to the determination result of the TDC of the signal generation point (S330).

More specifically, when the TDC of the signal generating point is the intake / exhaust TDC, the combustion analyzing apparatus keeps the signal setting order of the angle sensor and sequentially collects the combustion pressure data for one cycle according to the signal setting order of the angle sensor And conversely, when the TDC of the signal generation point is the compression TDC, the signal setting order of the angle sensor is changed, and the combustion pressure data for one cycle can be sequentially collected according to the signal setting order of the changed angle sensor.

That is, when the TDC of the signal generating point is the intake and exhaust TDC, the combustion analyzing apparatus collects the combustion pressure data for one cycle while maintaining the present state according to the signal setting sequence (0 and 1) of the angle sensor, When the TDC of the signal generation point is a compressed TDC, the signal setting sequence (0 and 1) of the angle sensor can be reversed (1 and 0) to collect the combustion pressure data for one cycle.

Next, a one-cycle data collection method according to the fourth embodiment of the present invention will be described.

FIG. 9 is a flowchart showing one cycle data collection method for output measurement and combustion analysis of a large low-speed four-stroke engine according to another embodiment of the present invention. FIG. 10 (a) FIG. 10 (b) is a graph showing the combustion pressure according to the rotation angle of the crankshaft when the compression TDC is first detected for 1.5 cycles. FIG. 10 (b) is a graph showing the combustion pressure according to the rotation angle of the crankshaft.

Referring to FIG. 9, the combustion analysis apparatus collects combustion pressure data for 1.5 cycles with the pulse signal (Z) of a predetermined angle sensor as a start signal (S410). For example, 1.5 cycles can mean 1080 degrees.

Next, the combustion analysis apparatus compares the combustion pressure data collected from the combustion pressure data for the first 1.5 cycles with the predetermined reference pressure to determine a data collection range corresponding to one cycle (S420).

Here, as shown in FIG. 10 (a), when the combustion pressure data collected for the first time is less than the reference pressure, the combustion analysis apparatus calculates the position (720 degrees) from the position at which the combustion pressure data was initially collected As shown in FIG. 10 (b), when the initially collected combustion pressure data is equal to or higher than the reference pressure, a position 1080 (from 360 degrees) to 1.5 cycles Can be determined as the data collection range.

Next, the combustion analysis apparatus collects combustion pressure data from a data collection range corresponding to the determined one cycle (S430).

Meanwhile, the one-cycle data collection method may be implemented in the form of a program command that can be executed through various computer means, and may be recorded in a computer-readable recording medium. Here, the recording medium may include a program command, a data file, a data structure, and the like. In addition, the program instructions recorded on the recording medium may be those specially designed and constructed for the present invention, or may be available to those skilled in the art of computer software. For example, the recording medium may be a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical medium such as a CD-ROM or a DVD, a magneto-optical medium such as a floptical disk, magneto-optical media, and hardware devices that are specially configured to store and perform program instructions such as ROM, RAM, flash memory, and the like. The program instructions may include machine language code such as those generated by the compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like. And, a hardware device may be configured to operate as one or more software modules to perform the operations of the present invention.

The method of measuring the output of the engine may also be implemented in the form of a computer program or an application executed by a computer stored in a recording medium.

As described above, according to the embodiment of the present invention, by obtaining accurate one-cycle data for the large-sized low-speed four-stroke engine, accurate combustion analysis and output measurement of the engine can be made possible.

In addition, since one cycle data of the large-sized low-speed four-stroke engine can be obtained through various methods such as compression TDC, Z pulse setting of the angle sensor, initial detection pressure comparison, etc., Thereby improving the reliability of the operation.

In addition, it is possible to acquire one cycle data of a large-sized low-speed four-stroke engine in a relatively simple manner compared with the conventional one, thereby improving convenience and workability of the operator, Costs can be saved by excluding the use of other equipment.

In addition, by providing accurate one-cycle data of a large-sized low-speed four-stroke engine, it is possible to perform an output measurement and a combustion analysis of the engine, thereby enabling the ignition timing and injection timing, fuel injection amount, The post combustion and the turbocharger matching relationship can be grasped precisely. Further, a solution for optimal combustion can be provided to selectively adjust the fuel injection timing, fuel injection amount, and turbocharger matching as necessary, Life and fuel consumption efficiency can be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

Claims (3)

A one-cycle data acquisition method for power measurement and combustion analysis of a large low speed four-stroke engine,
Collecting combustion pressure data for 1.5 cycles with a pulse signal of a predetermined angle sensor as a start signal;
Determining a data collection range corresponding to one cycle by comparing the combustion pressure data collected first among the collected combustion pressure data for the 1.5 cycles with a preset reference pressure; And
Collecting the combustion pressure data from a data collection range corresponding to the determined one cycle;
Lt; / RTI >
Comparing the first collected combustion pressure data among the collected combustion pressure data for the 1.5 cycles with the preset reference pressure to determine a data collection range,
Determining a position from the position at which the combustion pressure data is initially collected to one cycle as the data collection range when the combustion pressure data that was collected initially is less than the reference pressure,
Cycle data for the output and combustion analysis of a large-sized low-speed four-stroke engine for determining a position from a position where 0.5 cycle has elapsed to 1.5 cycles as the data collection range when the initially collected combustion pressure data is equal to or higher than the reference pressure. Collection method. delete A computer-readable recording medium recording a program for executing the method of claim 1 in a computer.

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