KR101865023B1 - System for measuring output of large-sized low-speed two stroke engine and method for measuring output of large-sized low-speed two stroke engine - Google Patents

Abstract

The output measuring system of the large-sized low-speed two-stroke engine according to the embodiment of the present invention is an output measuring system of a large-sized low-speed two-stroke engine for measuring the output of the engine for one cycle, ; An angle sensor unit for detecting a rotation angle of the crankshaft such that a Z pulse is coincident with an actual TDC of a predetermined reference cylinder; The combustion pressure of each crankshaft with respect to each cylinder, the combustion pressure of each cylinder with respect to the rotational angle of the crankshaft, the combustion pressure of each cylinder with respect to each cylinder, The crankshaft rotation angle of the crankshaft with respect to the remaining cylinders except for the reference cylinder is checked by confirming the position and loss angle of the compression TDC of the reference cylinder from a plurality of diagrams, And an output side section for measuring the output of each cylinder after adjusting the angle detection time.

Description

TECHNICAL FIELD [0001] The present invention relates to an output measuring system and an output measuring method for a large-sized low-speed two-stroke engine,

The present invention relates to an output measuring system and an output measuring method for a large low-speed two-stroke engine, and more particularly, to a large-low-speed two-stroke engine capable of measuring the output of the engine more accurately by eliminating a twist error and an explosion angle error of the crankshaft Output measuring system and an output measuring method.

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.

On the other hand, the electronic pressure gauge samples the pressure during one cycle of the engine through the time reference method or the angle reference method.

Sampling through the time reference method collects the pressure during one cycle of the engine according to the set time unit. Sampling through the angle reference method means a method of collecting the pressure during one cycle of the engine according to the set angle unit do.

However, there is a problem in that the sampling based on the time base method ignores the instantaneous speed fluctuation of the engine and causes a TDC (Top Dead Center) error.

Therefore, conventionally, sampling is mainly performed by an angle reference method in which an angle sensor (encoder) is installed at the end of a crankshaft to collect pressure.

That is, in the conventional ship engine monitoring apparatus, the output of the engine is measured by using an electronic paper pressure measuring technique using a sampling technique based on an angle reference method for precise and precise measurement.

On the other hand, since the TDC 1 degree (deg.) Error in the output measurement of the engine causes about 10% error of the engine output, the measurement of the TDC is very important in the measurement of the output of the engine. To the extent that the

However, in the conventional ship engine monitoring apparatus, when the output of the large-sized low-speed two-stroke engine is measured, the crankshaft twist and the explosion angle error of each cylinder are not considered. That is, in the conventional marine engine monitoring apparatus, since the Z pulse (signal generating pulse once per rotation) of the angle sensor mounted on the end of the crankshaft opposite to the flywheel coincides with the actual TDC of the first cylinder, However, for the remaining cylinders, the torsional error and the blast angle error of the crankshaft are not considered, and the error between the actual engine output and the measured output exceeds the reference error range. That is, in the conventional marine engine monitoring apparatus, since the flywheel of the engine is located on the opposite side of the cylinder No. 1 where the angle sensor is set, it is calculated that the twist due to the rotation occurs and relatively first rotates, There is a problem that the output value calculated by calculating to be placed before the actual value is calculated to be larger than the output value of the actual engine.

For example, when a conventional marine engine monitoring apparatus measures the output of a six-cylinder large-sized low-speed two-stroke engine, the explosion angle for each cylinder is designed at an interval of 60 degrees so that the TDC of the second cylinder is 60 Is calculated after assuming that it occurs later. However, in the case of an actual large-sized low-speed two-stroke engine, the explosion angle according to the explosion order does not progress at intervals of 60 degrees, and the crankshaft is twisted due to rotation, Is 15% or more. For reference, the larger the crankshaft torsion is, the greater the degree of twist is.

Korean Patent Publication No. 10-2015-0064837

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to check the deviation between the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders excluding the reference cylinder using a plurality of diagrams , The deviation between the cylinders is corrected by adjusting the detection time of the angle sensor unit, thereby eliminating the output error of each cylinder in accordance with the twist error and the explosion angle error of the crankshaft, A low-speed two-stroke engine output measuring system and an output measuring method.

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, an output measuring system of a large-sized low-speed two-stroke engine according to an embodiment of the present invention is an output measuring system of a large-sized low- A pressure sensor for detecting the pressure of the fluid; An angle sensor unit for detecting a rotation angle of the crankshaft such that a Z pulse is coincident with an actual TDC of a predetermined reference cylinder; And a control unit for collecting combustion pressures for the respective cylinders from the pressure sensor unit and the angle sensor unit at respective angles of rotation of the crankshaft to calculate combustion pressures for the respective cylinders for respective angles of rotation of the crankshaft, Wherein a plurality of graphs relating to a combustion pressure and a pressure fluctuation rate of each cylinder with respect to a rotational angle of the crankshaft are shown and from a diagram relating to the pressure fluctuation rate of each cylinder with respect to the rotational angle of the crankshaft, An output side unit for checking a position and a loss angle of the crankshaft of the crankshaft of the crankshaft of the angle sensor unit relative to the remaining cylinders except for the reference cylinder and measuring the output of each cylinder; .

Wherein the output side portion adjusts the rotation angle detection time point of the crankshaft of the angle sensor portion with respect to the remaining cylinders except for the reference cylinder to calculate a compression ratio of the reference cylinder The position of the TDC can be matched with the position of the compression TDC of the remaining cylinders except for the reference cylinder.

Wherein the output side portion determines a position and a loss angle of the compression TDC of the reference cylinder from a diagram related to the pressure variation rate of each cylinder by the rotation angle of the crankshaft, A diagram showing a trend line, and a table indicating the position of each of the above-mentioned compressed TDCs for respective cylinders.

Wherein the output side portion compares the position of the compression TDC of the reference cylinder with the position of the reference cylinder and the loss angle of the compression cylinder of the reference cylinder when the position and loss angle of the compression TDC of the reference cylinder are checked from a diagram relating to the pressure variation rate of each cylinder with respect to the rotation angle of the crankshaft. A table indicating the position correction values for the remaining cylinders except for the reference cylinder may be further calculated by calculating the difference in the positions of the compression TDCs of the remaining cylinders.

Meanwhile, a method for measuring the output of a large-sized low-speed two-stroke engine according to an embodiment of the present invention is a method for measuring the output of a large-sized low-speed two-stroke engine for measuring an output of an engine for one cycle, Matching a Z pulse with an actual TDC of the reference cylinder; A pθ diagram showing the combustion pressure for each cylinder by the angle of rotation of the crankshaft with respect to each cylinder and a dP diagram representing the rate of pressure change for each cylinder by the angle of rotation of the crankshaft ≪ / RTI > Confirming the position and loss angle of the compression TDC of the reference cylinder from the dP line; Wherein the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders excluding the reference cylinder in the dP diagram are adjusted by adjusting the rotation angle detection time of the crankshaft of the angle sensor unit with respect to the remaining cylinders except for the reference cylinder Matching step; And generating a PV diagram representing the combustion pressure of each cylinder relative to the volume of the combustion chamber, and measuring an output of each of the cylinders.

Wherein the step of confirming the position and the loss angle of the compression TDC of the reference cylinder from the dP line is a diagram showing a trend line relating to the position of each compression TDC and the degree of twist of each cylinder, Generating a table representing the table; The position and the loss angle of the compression TDC of the reference cylinder are checked through the dP line, the diagram showing the trend line about the position of each compression TDC for each cylinder and the degree of twist, and the table showing the position of each compression TDC for each cylinder step; Calculating a difference between a position of the compression TDC of the reference cylinder and a position of the compression TDC of the cylinder other than the reference cylinder to generate a table indicating a position correction value for the remaining cylinders except for the reference cylinder; .

According to the embodiment of the present invention, the deviation between the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders excluding the reference cylinder is checked using a plurality of diagrams, and the detection time of the angle sensor unit is adjusted, It is possible to accurately measure the output of the engine by eliminating the output error of each cylinder according to the twist error and the explosion angle error of the crankshaft.

In addition, since the output of the engine can be measured quickly and accurately as compared with the conventional output measuring apparatus, the reliability of the apparatus can be improved.

Also, by collecting accurate engine data for each cylinder in accordance with the angle signal, it is possible to accurately grasp Pmax and measure output, and further, by performing combustion analysis using the collected data, It is possible to accurately grasp the timing and timing of injection, the fuel injection amount per cylinder, knocking, post-combustion, and turbocharger matching relationship, and provides a solution for optimal combustion to control the fuel injection timing, fuel injection amount, The engine can be selectively adjusted to optimize the combustion, and the life of the engine and the fuel consumption efficiency can be improved.

1 is a block diagram schematically showing an output measuring system of a large-sized low-speed two-stroke engine according to an embodiment of the present invention.
FIG. 2 is a P? Diagram showing the combustion pressure of each cylinder measured by the output measuring system of the large-sized low-speed two-stroke engine according to the embodiment of the present invention and the combustion pressure of the crankshaft with respect to the angle of rotation of the crankshaft.
3 is a PV diagram showing the combustion pressure per combustion chamber volume for each cylinder measured through an output measurement system of a large low-speed two-stroke engine according to an embodiment of the present invention.
4 is a dP diagram showing the pressure fluctuation rate of each cylinder measured by the output measuring system of the large-sized low-speed two-stroke engine according to the embodiment of the present invention, with respect to the rotational angle of the crankshaft.
5 is an enlarged dP diagram of the portion " A " in Fig.
6 (a) is a graph showing trend lines relating to the position and degree of twist of each cylinder-specific compression TDC measured through the output measurement system of the large-sized low-speed two-stroke engine according to the embodiment of the present invention, b) is a table showing the position of the compression TDC of each cylinder.
FIG. 7 is a table showing correction values of the compression TDC for each cylinder calculated through the output measurement system of the large-low-speed two-stroke engine according to the embodiment of the present invention.
8 is a dP diagram showing the pressure fluctuation rate of the crankshaft with respect to each cylinder, which is corrected through the output measurement system of the large-sized low-speed two-stroke engine according to the embodiment of the present invention,
9 is a diagram showing output measurement results generated through an output measuring system of a large low-speed two-stroke engine according to an embodiment of the present invention.
10 to 11 are flowcharts showing a method of measuring the output of a large-sized low-speed two-stroke engine according to an embodiment of the present invention.

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.

1 is a block diagram schematically showing an output measuring system of a large-sized low-speed two-stroke engine according to an embodiment of the present invention.

1, an output measuring system 100 (hereinafter, referred to as an output measuring system 100) of a large-sized low-speed two-stroke engine according to an embodiment of the present invention includes a large- An output measurement system for measuring an output during a cycle, comprising a plurality of sensor units.

The plurality of sensor units include a pressure sensor unit 10 for detecting a signal relating to an individual combustion pressure of each cylinder (not shown) and an angle sensor unit 20 for detecting a signal relating to the rotational angle of a crankshaft (not shown) do.

The pressure sensor unit 10 is installed in a test cock (not shown) of the engine E / G to detect the individual combustion pressures of the cylinders provided in the engine. The pressure sensor unit 10 is electrically connected to an output side unit 30 to be described later, and transmits a signal regarding the individual combustion pressure of the detected cylinder to the output side unit 30. [

The angle sensor unit 20 is installed at an end of the crankshaft disposed on the opposite side of the flywheel (not shown), detects the rotation angle of the crankshaft, and is electrically connected to the output side unit 30, To the output side 30. Then, the Z pulse (signal for generating a pulse once per rotation) of the angle sensor unit 20 coincides with the actual TDC of the preset reference cylinder. Here, the reference cylinder means the first cylinder connected to the crankshaft and causing the first explosion when the engine is driven. The actual TDC is a center point between the instant when the piston reaches the position of the top dead center and the moment when the dial gauge stops moving and the moment when the dial gauge starts moving again when the piston is measured by the dial gauge. For reference, the actual TDC is marked on the flywheel of the engine. For example, the angle sensor unit 20 may be applied as an encoder having a preset resolution.

Between the plurality of sensors (the pressure sensor unit 10 and the angle sensor unit 20) and the output side unit 30, an analog signal transmitted from each sensor is converted into an analog signal A converter (not shown) may be further provided.

The output measurement system 100 also includes an output side 30.

The output side 30 is electrically connected to a plurality of sensors, receives signals relating to individual combustion pressures of the respective cylinders detected from the respective sensors and a rotation angle of the crankshaft, The combustion pressure of each crankshaft with respect to the rotational angle of the crankshaft is collected.

The output side unit 30 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 each crankshaft with respect to the rotational angle of the crankshaft, And is represented by a plurality of graphs relating to the volumetric combustion pressure and the rate of pressure fluctuation by the rotational angle of the crankshaft with respect to each cylinder.

Hereinafter, the analytical items and the lines analyzed through the output side 30 will be described in more detail.

FIG. 2 is a Pθ diagram showing the combustion pressure of each cylinder measured by the output measurement system of the large-sized low-speed two-stroke engine according to the rotation angle of the crankshaft according to the embodiment of the present invention, and FIG. FIG. 4 is a graph showing the relationship between the combustion pressure and the combustion pressure of the combustion chamber according to the output measurement system of the large-low-speed two-stroke engine according to the embodiment of the present invention. 5 is a dP plot showing the pressure fluctuation rate of the crankshaft with respect to each measured cylinder at a rotation angle, and Fig. 5 is an enlarged dP plot of the portion " A " 6 (a) is a graph showing trend lines relating to the position and degree of twist of each cylinder-specific compressed TDC measured by the output measuring system of the large-sized low-speed two-stroke engine according to the embodiment of the present invention, and Fig. 6 FIG. 7 is a table showing the position of the compression TDC of each cylinder calculated through the output measurement system of the large-sized low-speed two-stroke engine according to the embodiment of the present invention, . FIG. 8 is a dP diagram showing the pressure fluctuation rate of each cylinder corrected by the output measuring system of the large-sized low-speed two-stroke engine according to the rotation angle of the crankshaft according to the embodiment of the present invention, and FIG. Fig. 5 is a view showing output measurement results produced through an output measurement system of a large-sized low-speed two-stroke engine according to an example.

2, the output side portion 30 is a trigger of a signal of the angle sensor portion 20 that measures the rotation angle of the crankshaft, and detects the rotation angle of the crankshaft with respect to each cylinder for one cycle of the engine The star combustion pressure is collected, and it is shown on the X-axis as the rotation angle of the crankshaft for each cylinder, and on the Y-axis as the Pθ line representing the combustion pressure according to the rotation angle. For reference, the crankshaft is set to rotate at an angle of 360 degrees per one cycle of the engine.

Referring to FIG. 3, the output side 30 calculates the combustion chamber volume for each cylinder by the rotation angle of the crankshaft according to the following equations (1) and (2) It is represented by a line. 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.

[Equation 1]

In this equation, v (i) is the combustion chamber volume by the rotation angle, vc is the gap volume, s is the cross sectional area of the cylinder, X (i) is the piston displacement with respect to the rotation of the crankshaft, Comratio - 1.0), vh = s × stroke (height from top to bottom), s = 3.14 × bore² / 4. For example, i representing the crank angle may be set to 1 deg., 0.5 deg., 0.2 deg., Etc. according to sampling.

&Quot; (2) "

Here, rr is the crank radius, de is the crank angle, and ramda = l (length of the connecting rod) / rr.

Referring to FIG. 4, the output side 30 calculates the pressure fluctuation rate of each cylinder with respect to the rotational angle of the crankshaft, and expresses the pressure fluctuation rate of each cylinder with a dP diagram showing the pressure fluctuation rate of each cylinder with respect to the rotational angle of the crankshaft.

That is, the output side 30 differentiates the combustion pressure value for each cylinder with respect to the rotation angle of the crankshaft by the following Equation (3) to confirm a minute pressure change that is difficult to be confirmed in the P? .

&Quot; (3) "

Here, dP is the pressure fluctuation rate by the rotational angle, P is the sampled pressure, and i is the rotational angle of the crankshaft. Here, P representing the sampled pressure means absolute pressure. For example, if the sampled pressure is P0, then P = P0 + Patm (atmospheric pressure).

Further, the output side section 30 confirms the position of the compression TDC of the reference cylinder and the loss of angle from the diagram of the pressure fluctuation rate by the rotation angle of the crankshaft for each cylinder, that is, from the dP diagram.

More specifically, the output side 30 confirms the position of the compression TDC of the reference cylinder from the point where dp / d? = 0 when the crankshaft is located near 180 degrees through the dP diagram shown in Fig. That is, since the position of the compressed TDC indicates the position of Pcomp which is the point at which the pressure in the cylinder becomes the maximum by compressing the air in the cylinder before the fuel is injected, the Pcomp position in the dP line, that is, the first point where dp / (Around 180 degrees), the position of the compression TDC of each cylinder as well as the reference cylinder can be confirmed. 4, the point at which dp / d? = 0 when the crankshaft is located at about 195 degrees represents the Pmax position where the fuel is burned and becomes the combustion maximum pressure. Referring to FIG. 5, the output side 30 checks the position of the compressed TDC for each cylinder, checks the error of each compressed TDC for each cylinder, and calculates the loss angle of the reference cylinder. That is, since the Z pulse of the angle sensor unit 20 coincides with the actual TDC of the reference cylinder, the output side unit 30 determines the angle of the crankshaft corresponding to the position of the compression TDC of the reference cylinder, Calculate the difference to calculate the loss angle of the reference cylinder.

Here, when the position and the loss angle of the compression TDC of the reference cylinder are checked from the dP line, the output side 30 determines the position of each cylinder-compressed TDC and the degree of twist, as shown in Fig. 6 (a) A line indicating a trend line, and a table indicating the position of each cylinder-specific compressed TDC as shown in Fig. 6 (b). 6 (a), the compression TDC of the reference cylinder (cylinder # 1) is set to the position of 0, since it is assumed that the Z pulse of the encoder is matched with the correct TDC and that the reference cylinder The compression TDC of the remaining cylinders appears at a position separated by a deviation from the compression TDC of the reference cylinder. 6 (a), the output side 30 compares the position of the compression TDC of each cylinder with the trend line, confirms the position of the compression TDC of each cylinder deviates from the trendline, The degree of twist, and the presence or absence of an error of the explosion angle. 7, the output side 30 calculates the difference between the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders except for the reference cylinder, The position correction value for the position can be calculated and displayed in a table.

In addition, the output side 30 checks the position and loss angle of the compression TDC of the reference cylinder from the dP line and then applies the calculated correction value to the angle sensor unit 20, Thereby adjusting the rotation angle detection time of the crankshaft of the crankshaft 20.

That is, the output side portion 30 adjusts the rotation angle detection time point of the crankshaft of the angle sensor portion 20 with respect to the remaining cylinders except for the reference cylinder, so that the rotation of the crankshaft relative to each cylinder The position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders excluding the reference cylinder can be matched in the diagram (dP line) of the pressure fluctuation rate by angle.

The output side portion 30 adjusts the rotation angle detection timing of the crankshaft of the angle sensor portion 20 to match the position of the compression TDC of the reference cylinder with the position of the compression TDC of the remaining cylinders excluding the reference cylinder, Generate a PV plot showing the combustion pressure per combustion chamber volume for the cylinder and measure the output of each cylinder.

On the other hand, the output side unit 30 substitutes the data collected from each sensor unit into a preset formula to further analyze the heat generation rate and the combustion gas temperature for each cylinder, and calculates the heat generation rate And a plurality of diagrams relating to the combustion gas temperature by the rotation angle of the crankshaft for each cylinder.

Referring to FIG. 9, the output side 30 calculates the heat generation rate for each cylinder by the rotation angle of the crankshaft according to the following equations (4), (5) and (6) The heat generation rate indicating the heat generation rate can be indicated.

&Quot; (4) "

Here, ROHR (rate of heat release) is a heat generation rate by a rotation angle, A = 1.0 / 42700.0, and κ denotes a specific heat ratio.

&Quot; (5) "

= 1.4373,

= -1.318 ×

,

= 3.12 ×

,

= -4.8 ×

,

는 공기과잉률, T는 회전 각도별 연소가스 온도를 의미한다. 참고로, 연소가스 온도 T는 이상기체 상태방정식을 통해 계산되고, 이론적 공기량은 디젤유의 이론적 공기량인 14.5㎏f로 적용될 수 있다.here,

= 1.4373,

= -1.318 x

,

= 3.12 x

,

= -4.8 x

,

Is the excess air ratio, and T is the combustion gas temperature per rotation angle. For reference, the combustion gas temperature T is calculated through the ideal gas state equation, and the theoretical air amount can be applied to the theoretical air amount of 14.5 kgf of diesel fuel.

&Quot; (6) "

Rr is the crank radius, de is the angle of rotation of the crankshaft, ramda = l (length of the connecting rod) / rr, where dv is the volume of the divided combustion chamber, dr = pai (3.141593) / 180, s = 3.14 x bore² / . For reference, the resolution of the encoder means the unique pulse value of the encoder, and any encoder having any resolution through the formula of 360 / encoder resolution can be applied to Equation (6).

The output side 30 calculates the combustion gas temperature for each cylinder by the rotation angle of the crankshaft according to the following expression (7), and calculates the combustion gas temperature for each cylinder based on the combustion gas Can be represented by a temperature diagram.

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 output side 30 can calculate the combustion gas temperature by the rotation angle of the crankshaft using the ideal gas state equation.

&Quot; (7) "

Here, T (i) is the combustion gas temperature, G is the gas weight, R is the gas constant, P (i) is the combustion chamber pressure by the rotation angle, and V (i) is the combustion chamber volume by the rotation angle.

The gas weight G in the equation (7) can be calculated by the following equation (8).

&Quot; (8) "

Here, P denotes an initial pressure (or a scavenging pressure), V denotes a combustion chamber volume, T denotes an initial temperature (or a scavenging temperature), and? Denotes an intake air filling efficiency of the engine. For example, the intake air filling efficiency of the engine is preferably 0.8 for four strokes, and 0.75 for two strokes, but is not limited thereto and may be adjusted according to the filling efficiency. That is, since the stroke is clear in comparison with the two-stroke engine in the case of four strokes, the intake air filling efficiency of the engine can be higher than that of the two-stroke engine.

The output side 30 may further analyze the instantaneous speed of the engine by the rotational angle of the crankshaft to further represent the instantaneous speed fluctuation diagram.

Referring to Fig. 9, the output side 30 calculates the instantaneous speed of the engine by the rotational angle of the crankshaft during one cycle of the engine according to the following equation (9) and outputs it to the crankshaft rotation And can be represented by an instantaneous speed fluctuation line indicating the instantaneous speed of the engine by angle.

For reference, the engine does not rotate at a constant speed during one revolution because the instantaneous speed of each cylinder varies due to compression process and explosion process. Therefore, since the large-sized low-speed engine rotates at a low speed, the instantaneous speed is varied by the number of cylinders in one rotation.

The instantaneous speed of the engine can be defined by Equation (9) below.

&Quot; (9) "

The instantaneous speed is the instantaneous speed of the engine, the encoder resolution is the number of pulses (resolution) of the encoder, the count clock time is the speed of the internal count signal between pulses, and the count number is the internal count calculated by the speed of the internal count signal between pulses. Means the number of count signals.

Further, the output side section 30 can analyze at least two of the generated plurality of diagrams to determine the combustion state of the engine.

More specifically, the output-side section 30 analyzes at least two of the plurality of diagrams and calculates the fuel consumption state of each cylinder, the fuel injection state of each cylinder, the fuel consumption state of each cylinder, , The knocking state of the engine, the post-combustion state of each cylinder, and whether or not the combustion maximum pressure between the cylinders coincide with each other.

In addition, the output-side unit 30 may further display a table including at least one analysis data together with a plurality of diagrams.

Referring to FIG. 9, the output side 30 measures the output of the engine and outputs the measured results to the engine rpm, compression maximum pressure Pcomp, maximum combustion pressure Pmax, (IMEP), Indicated Horse Power (IHP), Brake Horse Power (BHP), Rate of Heat Release (ROHR), and the like. And a specific fuel consumption (SFC).

Hereinafter, a method of measuring the output of a large-sized low-speed two-stroke engine 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 output measurement method of the present engine, and the same or redundant description will be omitted.

10 to 11 are flowcharts showing a method of measuring the output of a large-sized low-speed two-stroke engine according to an embodiment of the present invention.

The output measurement method of the engine is performed through the output measurement system 100 as an output measurement method of a large-sized low-speed two-stroke engine that measures the output of the engine for one cycle.

Referring to FIG. 10, the output measurement system 100 coincides the Z pulse of the angle sensor unit 20 mounted on the preset reference cylinder with the actual TDC of the reference cylinder (S100).

Next, the present output measuring system 100 collects combustion pressures for the respective cylinders by the rotational angle of the crankshaft, and calculates a P? Line representing the combustion pressure for each cylinder with respect to the rotational angle of the crankshaft and a crankshaft A dP diagram showing a pressure fluctuation rate for each rotation angle is generated (S200).

That is, the output measuring system 100 collects the combustion pressure of each cylinder with respect to the rotational angle of the crankshaft after matching the Z pulse of the angle sensor unit 20 with the actual TDC of the reference cylinder, As shown in Fig. 4, a p &thetas; diagram such as that shown in Fig. 4 is generated and the collected data is applied to a preset formula to generate a dP diagram as shown in Fig.

Next, the output measuring system 100 confirms the position and the loss angle of the compression TDC of the reference cylinder from the dP diagram as shown in FIG. 10 (S300).

More specifically, referring to Fig. 11, the present output measuring system 100 generates a chart showing trend lines relating to the position and twist of each cylinder-by-cylinder compressed TDC and a table showing the position of each cylinder-specific compressed TDC (S310), the position and loss angle of the compression TDC of the reference cylinder are checked through the dP diagram, the diagram showing the trend line of the position of the compression TDC for each cylinder and the degree of twist, and the table showing the position of each compression TDC for each cylinder (S320). From this, the difference between the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders except for the reference cylinder is calculated to generate a table indicating the position correction values for the remaining cylinders except for the reference cylinder (S330).

That is, the present output measuring system 100 is a diagram showing the dP diagram shown in Figs. 4 and 5, a trend line showing the position and degree of twist of each cylinder-specific compressed TDC shown in Fig. 6 (a) 6 (b), the position of the compression TDC of each cylinder (the point at which dp / d? = 0 when the crankshaft is located near 180 degrees) , The loss angle of the reference cylinder, the error of the compression TDC of each cylinder, the torsion of the crankshaft, and the error of the blast angle, and then the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders Respectively, and can be represented by a table of position correction values of the remaining cylinders except the reference cylinder as shown in FIG. For example, referring to FIG. 5 and FIG. 6B, the compression TDC position of the reference cylinder (first cylinder) is 179.85 degrees, the reference cylinder has a loss angle of 0.15 degrees, Is about 1 degree at the maximum. 6 (a), it can be confirmed that the explosion angle error is generated because the position of the compression TDC of each cylinder deviates from the trendline according to the explosion order. Accordingly, correction values for the remaining cylinders can be calculated as shown in FIG.

Next, the output measurement system 100 adjusts the rotation angle detection timing of the crankshaft of the angle sensor unit 20 for the remaining cylinders except for the reference cylinder through the calculated position correction value as shown in FIG. 10 , the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders except for the reference cylinder are matched with each other in the dP diagram (S400).

That is, the output measurement system 100 adjusts the rotation angle detection timing of the crankshaft of the angle sensor unit 20 with respect to the cylinders other than the reference cylinder, so that the crankshaft The position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders except for the reference cylinder can be matched with each other in the diagram (dP line) relating to the pressure fluctuation rate by the rotation angle of the cylinder.

Next, the output measurement system 100 generates a PV diagram representing the combustion pressure of each cylinder according to the combustion chamber volume, and measures the output of each cylinder (S500).

That is, the output measurement system 100 adjusts the rotation angle detection time of the crankshaft of the angle sensor unit 20 to match the position of the compression TDC of the reference cylinder with the position of the compression TDC of the remaining cylinders excluding the reference cylinder (IHP, urban horsepower) per cylinder by generating a PV diagram representing the combustion pressure of each cylinder per cylinder volume as shown in FIG. 3 and calculating the area of the diagram using a preset formula Can be measured.

In addition, the present output measuring system 100 can further determine the combustion state of the engine through a plurality of diagrams shown in FIG.

Meanwhile, the output measurement method of the present engine may be implemented in the form of a program command which can be executed through various computer means and 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, the deviation between the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders excluding the reference cylinder is checked using a plurality of diagrams, By correcting the deviation between the cylinders, it is possible to accurately measure the output of the engine by eliminating the output error of each cylinder according to the twist error and the explosion angle error of the crankshaft.

In addition, since the output of the engine can be measured quickly and accurately as compared with the conventional output measuring apparatus, the reliability of the apparatus can be improved.

 Also, by collecting accurate engine data for each cylinder in accordance with the angle signal, it is possible to accurately grasp Pmax and measure output, and further, by performing combustion analysis using the collected data, It is possible to accurately grasp the timing and timing of injection, the fuel injection amount per cylinder, knocking, post-combustion, and turbocharger matching relationship, and provides a solution for optimal combustion, so that the timing of fuel injection, fuel injection amount, The engine can be selectively adjusted to optimize the combustion, and the life of the engine and the 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.

100: Output measurement system
10: Pressure sensor section
20:
30: output side

Claims (7)

An output measuring system of a large low-speed two-stroke engine for measuring the output of an engine for one cycle,
A pressure sensor unit for detecting an individual combustion pressure of each cylinder;
An angle sensor unit for detecting a rotation angle of the crankshaft such that a Z pulse is coincident with an actual TDC of a predetermined reference cylinder; And
Wherein the combustion pressure of each crankshaft is calculated for each of the cylinders by the rotational angle of the crankshaft, and the combustion pressure is calculated for each of the cylinders by the rotational angle of the crankshaft, Pressure and the rate of change of pressure with respect to the rotation angle of the crankshaft with respect to each of the cylinders, and from the diagram relating to the pressure change rate of each cylinder with respect to the rotation angle of the crankshaft, the compression TDC of the reference cylinder An output side part for confirming a position and a loss angle of the crankshaft of the other cylinder except the reference cylinder and adjusting an angle of detection of a rotation angle of the crankshaft of the angle sensor part and measuring an output of each cylinder;
The output measurement system of a large low-speed two-stroke engine. The method according to claim 1,
Wherein the output side portion adjusts the rotation angle detection time point of the crankshaft of the angle sensor portion with respect to the remaining cylinders except for the reference cylinder to calculate a compression ratio of the reference cylinder The output measuring system of the large-sized low-speed two-stroke engine for matching the position of the TDC with the position of the compression TDC of the remaining cylinders except for the reference cylinder. The method according to claim 1,
Wherein the output side portion determines a position and a loss angle of the compression TDC of the reference cylinder from a diagram related to the pressure variation rate of each cylinder by the rotation angle of the crankshaft, And further generates a chart indicating the position of the compression TDC for each cylinder. The method according to claim 1,
Wherein the output side portion compares the position of the compression TDC of the reference cylinder with the position of the compression cylinder of the reference cylinder and the loss angle of the compression cylinder of the reference cylinder when the position of the compression TDC and the loss angle of the compression cylinder of the reference cylinder are checked, Wherein the difference between the positions of the compressed TDCs of the remaining cylinders is calculated to further generate a table showing the position correction values for the remaining cylinders except for the reference cylinder. A method of measuring the output of a large low-speed two-stroke engine for measuring an output of an engine for one cycle,
Matching the Z pulse of the angle sensor unit mounted on the preset reference cylinder with the actual TDC of the reference cylinder;
A pθ diagram showing the combustion pressure for each cylinder by the angle of rotation of the crankshaft with respect to each cylinder and a dP diagram representing the rate of pressure change for each cylinder by the angle of rotation of the crankshaft ≪ / RTI >
Confirming the position and loss angle of the compression TDC of the reference cylinder from the dP line;
Wherein the position of the compression TDC of the reference cylinder and the position of the compression TDC of the remaining cylinders excluding the reference cylinder in the dP diagram are adjusted by adjusting the rotation angle detection time of the crankshaft of the angle sensor unit with respect to the remaining cylinders except for the reference cylinder Matching step; And
Generating a PV curve representing the combustion pressure of each cylinder relative to the volume of the combustion chamber, and measuring an output of each of the cylinders;
Wherein the method comprises the steps of: 6. The method of claim 5,
Confirming the position and loss angle of the compression TDC of the reference cylinder from the dP line,
A diagram showing a trend line on the position and degree of twist of each cylinder-by-cylinder compression TDC, and a table indicating the position of each cylinder-by-cylinder compression TDC;
The position and the loss angle of the compression TDC of the reference cylinder are checked through the dP line, the diagram showing the trend line about the position of each compression TDC for each cylinder and the degree of twist, and the table showing the position of each compression TDC for each cylinder step; And
Calculating a difference between a position of the compression TDC of the reference cylinder and a position of the compression TDC of the cylinder other than the reference cylinder to generate a table indicating a position correction value for the remaining cylinders except the reference cylinder;
Wherein the method comprises the steps of: A computer-readable recording medium recording a program for executing the method of claim 5 or 6 in a computer.

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