Engine condition estimation device, engine condition estimation method, and engine condition estimation program

Abstract

To provide an engine condition estimation device which can estimate conditions of an engine with stable accuracy.SOLUTION: An engine condition estimation device 100 estimates conditions of an engine 200 and includes: an air density measuring data acquisition part 110 which acquires measuring data of parameters related to a density of air suctioned by the engine 200 and supplied to a combustion part; and a condition estimation part 120 which estimates the conditions of the engine 200 based on the air density measuring data and a fuel supply amount U to the combustion part which is input to an engine model indicating characteristics of the engine 200.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technology for estimating an engine state. [Background technology]

[0002] Engines are widely used in ships, automobiles, aircraft, etc., but due to growing awareness of environmental issues, there has been a demand in recent years for even higher efficiency in engines, and various technologies to achieve this are being developed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-307800 A [Patent Document 2] JP 2015-222074 A [Patent Document 3] JP 2015-3658 A Summary of the Invention [Problem to be solved by the invention]

[0004] As an example, a simulation technique for engine parameters is known, as disclosed in Patent Document 1. Patent Document 1 uses a predetermined computational model to simulate the tuning frequency of the pressure wave in the intake pipe as an engine parameter. However, the operation and state of the engine change from moment to moment, and there is a problem in that even if the same computational model is used to perform the simulation, there is variation in the accuracy.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide an engine state estimating device that can estimate the state of an engine with stable accuracy. [Means for solving the problem]

[0006] In order to solve the above problems, an engine state estimation device of one embodiment of the present invention is an engine state estimation device that estimates the state of an engine that has a combustion section that generates power by combusting air and fuel, and a supercharger that increases the pressure of the intake air and supplies it to the combustion section, and includes an air density measurement data acquisition section that acquires measurement data of parameters related to at least one of the densities of the air intake by the supercharger and the compressed air supplied by the supercharger to the combustion section, and a state estimation section that estimates the state of the engine based on the air density measurement data and the amount of fuel supplied to the combustion section that is input into an engine model that represents the characteristics of the engine.

[0007] In this aspect, at least one parameter related to density of the air taken in by the supercharger and the compressed air which the supercharger increases the pressure of and supplies to the combustion section is measured, and the engine state is estimated using the parameter. This parameter represents the density of the air used in combustion in the combustion section, and among many engine-related parameters, it has a particularly large effect on the operation or state of the engine. Therefore, when this parameter fluctuates, the engine state fluctuates significantly, which is a factor in causing a large variation in the accuracy of state estimation. In the present invention, such a parameter which has a large effect on the engine state can be measured as air density measurement data and used for state estimation, so that the engine state can be estimated with stable accuracy.

[0008] Another aspect of the present invention is an engine state estimation method for estimating a state of an engine including a combustion section that generates power by combusting air and fuel and a supercharger that increases the pressure of the intake air and supplies it to the combustion section, the method including an air density measurement data acquisition step of acquiring measurement data of parameters related to at least one density of the air intake by the supercharger and the compressed air supplied by the supercharger to the combustion section, and a state estimation step of estimating the state of the engine based on the air density measurement data and an amount of fuel supplied to the combustion section that is input to an engine model that represents characteristics of the engine.

[0009] Any combination of the above components, and any transformation of the present invention into a method, device, system, recording medium, computer program, etc., are also effective as aspects of the present invention. Effect of the Invention

[0010] According to the present invention, the state of the engine can be estimated with stable accuracy. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a configuration of an engine state estimating device according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram showing the configuration of a four-stroke engine. [Diagram 3] FIG. 1 is a schematic diagram showing the configuration of a two-stroke engine. [Figure 4] FIG. 1 illustrates the effect of air density measurement data on engine power output. [Diagram 5] FIG. 1 illustrates the effect of air density measurement data on engine fuel economy. [Figure 6] FIG. 4 is a diagram showing the effect of air density measurement data on the temperature of gas flowing through the engine. [Figure 7] FIG. 4 is a diagram showing the influence of air density measurement data on the pressure of gas flowing through the engine. [Figure 8] FIG. 4 is a schematic diagram showing a configuration of an engine state estimating device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The engine state estimating device of this embodiment estimates the state of the engine using a mathematical model that represents the characteristics of the engine. Among many engine-related parameters, the temperature and pressure of the air used for fuel combustion, which have a large effect on the engine output and fuel efficiency, are measured and used for state estimation, thereby improving the accuracy of the estimation.

[0013] 1 is a schematic diagram showing the configuration of an engine state estimating device 100 according to the first embodiment. The engine state estimating device 100 is a device that estimates the state of an engine 200, and includes an air density measurement data acquiring unit 110 and a state estimating unit 120.

[0014] Before describing each component of the engine state estimating device 100, the engine 200, which is the object of the state estimation, will be described with reference to Figs. 2 and 3.

[0015] 2 is a schematic diagram showing a so-called four-stroke engine as an example of an engine 200. As will be described later, a four-stroke engine is an engine in which one cycle, consisting of four processes of intake, compression, combustion, and exhaust, is performed by four up and down movements of the piston (two ups and two downs).

[0016] The engine 200 includes a combustion section 210 that mixes air and fuel and burns the mixture to generate power, and a supercharger 240 that increases the pressure of the intake air and supplies it to the combustion section 210. The supercharger 240 is a so-called turbocharger, and includes a turbine 242 that is rotated by gas discharged after combustion in the combustion section 210, and a compressor 241 that is coaxially coupled to the turbine 242 by a shaft 243 and rotates in conjunction with the turbine 242.

[0017] Compressor 241 is provided at one end of air intake passage 220, one end of which is open to the outside air (atmosphere) and the other end of which is connected to combustion section 210, and draws in outside air by rotating and compresses it at the same time. The air compressed and pressurized by compressor 241 is supplied to combustion section 210 through air intake passage 220 and used for burning fuel there. Air intake passage 220 includes an intake pipe 221 through which air drawn in by compressor 241 from one end open to the outside air flows, an air intake pipe 222 through which compressed air supplied by compressor 241 to combustion section 210 flows, and an air intake receiver 223 provided at the other end near combustion section 210 and serving as an air intake accommodation section for accommodating compressed air. In addition, in order to prevent the air compressed by the compressor 241 from expanding due to a rise in temperature, an intake air cooler 224, which is a cooler for cooling the compressed air flowing through the intake air pipe 222, is provided midway through the intake air pipe 222. As a result, the temperature of the compressed air that is cooled while flowing through the intake air cooler 224 and is received in the intake air receiver 223 is kept within a certain range.

[0018] The turbine 242 is provided at the other end side of the exhaust path 230, one end of which is connected to the combustion section 210 and the other end of which is open to the outside air (atmosphere). The gas discharged after combustion in the combustion section 210 rotates the turbine 242 with its momentum, and is then released to the outside air from the other end of the exhaust path 230. The exhaust path 230 includes an exhaust receiver 231 provided at a position close to the combustion section 210 on the one end side as an exhaust accommodation section for accommodating the gas discharged after combustion in the combustion section 210, an exhaust pipe 232 through which the exhaust gas flows from the exhaust receiver 231 toward the turbine 242, and a turbine outlet pipe 233 through which the exhaust gas flows from the turbine 242 until it is released to the outside air from the other end.

[0019] The combustion section 210 includes a combustion chamber 211 in which combustion of fuel with air occurs, a fuel supply nozzle 212 that supplies an amount of fuel into the combustion chamber 211 specified by a fuel supply amount U per combustion, an intake valve 213 that controls the supply of air from an air intake receiver 223 to the combustion chamber 211, an exhaust valve 214 that controls the discharge of gas from the combustion chamber 211 to an exhaust receiver 231, a piston 215 that is driven linearly in response to the combustion of fuel in the combustion chamber 211, a crankshaft 216 as a rotary drive section that is driven to rotate in accordance with the linear movement of the piston 215, and a connecting rod 217 having one end fixed to the piston 215 and the other end fixed to the crankshaft 216 for converting the linear movement of the piston 215 into the rotational movement of the crankshaft 216. In the above embodiment, fuel is supplied directly into the combustion chamber 211 by the fuel supply nozzle 212. However, when using a highly volatile fuel such as gasoline, the fuel may be injected into the intake receiver 223 or the intake pipe 222 and mixed with air before being supplied into the combustion chamber 211.

[0020] In the above configuration, engine 200 is driven in the following cycle. Here, engine 200 is assumed to be in operation due to driving in the previous cycle or by driving due to multi-cylinder combustion, and piston 215 repeats rising and falling in response to the operation of crankshaft 216 which continues to rotate.

[0021] (1) Intake: Air is supplied from the intake receiver 223 to the combustion chamber 211 as the intake valve 213 opens, the exhaust valve 214 closes, and the piston 215 descends. (2) Compression: When the intake valve 213 closes and the piston 215 rises, the air in the combustion chamber 211 is compressed. (3) Combustion: Fuel is supplied from the fuel supply nozzle 212 into the combustion chamber 211 in an amount designated by the fuel supply amount U per combustion, and is burned in the compressed air. This generates power, causing the piston 215 to move down. (4) Exhaust: When the exhaust valve 214 opens and the piston 215 rises, the gas after combustion is discharged from the combustion chamber 211 to the exhaust receiver 231.

[0022] Fig. 3 is a schematic diagram showing a combustion section of a so-called two-stroke engine as another example of engine 200 (components corresponding to those in Fig. 2 are given the same reference numerals and explanations are omitted where appropriate). Unlike the four-stroke engine in Fig. 2 in which one cycle is completed by four up and down movements of the piston, in a two-stroke engine, one cycle is completed by a total of two up and down movements of the piston, one up and one down.

[0023] Similar to the above-mentioned four-stroke engine, the combustion section 210 of the two-stroke engine drives a piston 215 in a straight line by burning fuel in a combustion chamber 211, and converts it into rotational power of a crankshaft 216. The main structures of both types of engines are almost the same, but one difference is that the two-stroke engine is provided with a scavenging passage 219 that connects a crankcase 218 that houses the crankshaft 216 and the combustion chamber 211 in the combustion section 210.

[0024] In the illustrated state in which the piston 215 is descending, gas can flow through the crankcase 218, the scavenging passage 219, the combustion chamber 211, and the exhaust passage 230, and new air in the crankcase 218 flows into the combustion chamber 211 through the scavenging passage 219, and the momentum of the air causes the post-combustion gas to be discharged into the exhaust passage 230 (scavenging).

[0025] When the piston 215 subsequently rises, it closes the scavenging passage 219 and the exhaust passage 230, sealing off the combustion chamber 211 and increasing its pressure. Then, fuel is supplied from the fuel supply nozzle 212 into the now-pressurized combustion chamber 211, causing combustion, and generating power to move the piston 215 down again. Meanwhile, when the piston 215 rises, the crankcase 218 and the air intake passage 220 communicate with each other, and new air flows from the air intake passage 220 into the crankcase 218. In this way, when the piston 215 rises, combustion in the combustion chamber 211 and air intake to the crankcase 218 occur simultaneously.

[0026] As described above, in a two-stroke engine, one cycle is completed by a total of two strokes, one downward movement and one upward movement of the piston 215. In such a two-stroke engine, if the turbocharger 240 shown in Fig. 2 is used, it is possible to increase the pressure of the air supplied to the crankcase 218 when the piston 215 ascends, and the pressure of the scavenging air to the combustion chamber 211 when the piston 215 descends.

[0027] As the two-stroke engine, one having a configuration as disclosed in Patent Document 2 may be used. In this two-stroke engine, as described above with respect to FIG. 3, when the piston (41: the symbol in Patent Document 2 (hereinafter the same)) is descending, gas can flow through the scavenging receiver (2) corresponding to the intake receiver 223, the scavenging port (17) corresponding to the crankcase 218 and the scavenging passage 219, the cylinder (1) corresponding to the combustion chamber 211, and the exhaust duct (6) corresponding to the exhaust passage 230, and new air in the scavenging receiver flows into the cylinder through the scavenging port, and a scavenging operation is performed in which the gas after combustion is discharged to the exhaust duct by the force of the air. In addition, if a turbocharger 240 is used in such a configuration, the pressure of the scavenging air in the scavenging receiver can be increased.

[0028] The present embodiment can be applied to various types of engines 200 as described above, regardless of the application, such as for ships, vehicles, and aircraft, but is particularly suitable for use with ship engines having a rated speed of 1000 revolutions per minute or less. In general, ship engines are driven at the above-mentioned low rated speed compared to vehicle engines. In particular, in large ships, accurate engine drive is required because it takes time for the power generated by the engine to be reflected in the actual movement of the ship. Thus, in ship engines, there is a strong demand for accurate drive by estimating the engine state with high accuracy, and it is preferable to use the engine state estimation device 100 of the present embodiment.

[0029] The engine 200 of this embodiment can be used in a ship having the configuration disclosed in Patent Document 3, for example. That is, the engine 200 of this embodiment is used as a main engine (10: the symbol in Patent Document 3 (the same applies below)) that generates the propulsive force of the ship, and the power generated therein is transmitted to the propeller (14) via a drive shaft, causing the propeller (14) to rotate, generating the propulsive force of the ship.

[0030] In the engine 200 configured as above, the gas used for burning fuel flows through the following route: outside air → intake pipe 221 → compressor 241 → air intake pipe 222 → air intake receiver 223 → combustion section 210 (combustion chamber 211) → exhaust receiver 231 → exhaust pipe 232 → turbine 242 → turbine outlet pipe 233 → outside air.

[0031] In this embodiment, sensors for measuring parameters related to air density, specifically parameters such as pressure and temperature, can be installed at various points in the gas flow path. As shown in the figure, the sensor installation positions are classified into the following three positions, S0 to S2. S0: Intake pipe 221 S1: Inside the air supply pipe 222 S2: Inside the air intake receiver 223

[0032] A sensor for measuring the pressure and temperature of the outside air drawn in by the compressor 241 can be installed at the sensor installation position S0 in the intake pipe 221. To enable stable measurements, the sensor installation position S0 in the intake pipe 221 is preferably located at a predetermined distance from the open end of the intake pipe 221 that is open to the outside air and the inlet of the compressor 241. If the sensor is installed too close to the open end to the outside air, the measurement data will be easily affected by sudden changes in the outside air, and if the sensor is installed too close to the inlet of the compressor 241, the measurement environment may become unstable due to the influence of the air current generated by the rotating compressor 241.

[0033] At sensor installation position S1 in air intake pipe 222, a sensor can be installed to measure the pressure and temperature of compressed air that is increased in pressure by compressor 241 and supplied to combustion section 210. Regarding temperature, the temperature of the compressed air may be measured directly, or the cooling temperature by air intake cooler 224 that cools the compressed air, i.e., the temperature of a refrigerant such as cooling water, may be measured indirectly. Note that if the cooling temperature by air intake cooler 224 is constant and the temperature of the compressed air in air intake pipe 222 can be considered constant, it is not important to measure the temperature at sensor installation position S1, and it is therefore preferable to measure the pressure.

[0034] Furthermore, in order to enable stable measurements, the sensor installation position S1 in the air supply pipe 222 is preferably a position that is a predetermined distance away from the outlet of the compressor 241. More preferably, the sensor is installed at a position subsequent to the air supply cooler 224, after the compressed air has been sufficiently cooled, enabling more stable measurements. In particular, when the cooling temperature by the air supply cooler 224 can be considered constant, the temperature of the compressed air can also be considered constant, so that the state of the compressed air in the air supply pipe 222 can be grasped with high accuracy by measuring only the pressure.

[0035] At sensor installation position S2 in intake air receiver 223, a sensor for measuring the pressure and temperature of compressed air supplied to combustion section 210 can be installed. As with intake air pipe 222 described above, if the cooling temperature by intake air cooler 224 is constant and the temperature of the compressed air in intake air receiver 223 can be considered constant, it is not important to measure the temperature at sensor installation position S2, so it is preferable to measure the pressure.

[0036] In order to enable stable measurements, the sensor installation position S2 in the intake air receiver 223 is preferably located at a predetermined distance from the compressed air inlet from the intake air pipe 222 and the compressed air outlet to the combustion section 210. This allows stable measurements to be made while avoiding the effects of irregular airflow that may occur at these locations. Furthermore, if the cooling temperature by the intake air cooler 224 can be considered constant, the temperature of the compressed air in the intake air receiver 223 can also be considered constant, so that the state of the compressed air in the intake air receiver 223 can be grasped with high accuracy by measuring only the pressure.

[0037] The parameters measurable at the three sensor installation positions S0 to S2 described above represent the density of air used in combustion in the combustion section 210, and are used to estimate the state of the engine 200 by the engine state estimation device 100, as described below. Here, it is not necessary to install sensors at all of the three sensor installation positions S0 to S2, and installing a sensor at at least one of them is sufficient to estimate the state of the engine 200. On the other hand, when sensors are installed at multiple sensor installation positions among S0 to S2, or when multiple sensors of different types are installed at one sensor position, the accuracy of estimation of the state of the engine 200 can be improved based on the multiple measurement data obtained therefrom.

[0038] Returning to FIG. 1, the individual components (air density measurement data acquisition unit 110, state estimation unit 120) of engine state estimation device 100 that estimates the state of engine 200 will be described.

[0039] The air density measurement data acquisition unit 110 acquires various air density measurement data measured at the sensor installation positions S0 to S2. Specifically, the measurement data of the outside air sucked in by the compressor 241 is acquired from the sensor installation position S0 (in the intake pipe 221), and the measurement data of the air that the compressor 241 increases the pressure of and supplies to the combustion section 210 is acquired from the sensor installation positions S1 (in the intake pipe 222) and S2 (in the intake receiver 223).

[0040] The state estimation unit 120 that estimates the state of the engine 200 includes a calculation unit 121 that calculates state variables, which are parameters related to the state of the engine 200, based on an engine model that represents the characteristics of the engine 200. The engine model of the calculation unit 121 is a mathematical model of various characteristics of the engine 200, such as thermal efficiency, power transmission efficiency, dynamic characteristics, supercharger efficiency, and disturbance effects. The calculation unit 121 performs calculations using the amount of fuel supply U per combustion supplied to the combustion unit 210, measurement data Ne of the rotation speed of the crankshaft 216 that generates rotational power in the combustion unit 210, and the like as input data, and outputs estimated values ​​of each state variable of the engine 200 as engine state estimation results. As will be described later, in this embodiment, in addition to the fuel supply amount U and the rotation speed Ne, the air density measurement data acquired by the air density measurement data acquisition unit 110 is also input to the engine model, so that the state of the engine 200 can be estimated with high accuracy. Note that various methods for configuring the engine model are possible, but as a simple example, the calculation unit 121 calculates the output It can be configured as a table in which the estimated values ​​of each state variable of the engine 200 are associated with each other.

[0041] Examples of state variables of the engine 200 that can be estimated by the state estimation unit 120 include the following:

[0042] Parameters related to the operation of the combustion section 210: The rotation speed of the crankshaft 216 (the rotation speed Ne of the combustion section 210) Parameters related to the operation of the supercharger 240: The rotation speed of the compressor 241, the turbine 242, and the shaft 243 (the rotation speed Ntc of the turbocharger 240) In this embodiment, since the rotation speed Ne is acquired as measurement data, it is not necessary for the state estimation unit 120 to estimate it.

[0043] The following are state variables of the engine 200 that can be acquired as measurement data by the air density measurement data acquisition unit 110. In this embodiment, the state variables acquired as measurement data in this manner do not need to be estimated by the state estimation unit 120. Parameters related to the outside air drawn into the compressor 241 (measurable at S0 in the intake pipe 221): Outside air pressure (Pa) Outside air temperature (outside air temperature Ta) Parameters related to the compressed air (intake air) that the compressor 241 increases the pressure and supplies to the combustion section 210 (can be measured at S1 in the intake pipe 222 and S2 in the intake air receiver 223): - Pressure of intake air (intake pressure Pb / also written as scavenging pressure Ps in two-stroke engines with scavenging operation) - Temperature of intake air (Tb, also called scavenging air temperature Ts in two-stroke engines with scavenging operation) - Temperature of the cooling water in the air cooler 224 (cooling water temperature Tw)

[0044] In addition to the above, parameters related to the gas flowing through each part in the engine 200: Flow rate in the intake pipe 221, the intake pipe 222, and the intake receiver 223 Pressure, temperature, and flow rate in the exhaust receiver 231, exhaust pipe 232, and turbine outlet pipe 233

[0045] Using the above parameters, the engine model can calculate various engine 200 performances: Performance related to the power generated by the engine 200 (torque, output, etc.) Performance of the engine 200 with respect to fuel consumption (fuel consumption per unit time (hereinafter, abbreviated as fuel efficiency), fuel consumption rate per unit time and unit output, travel distance per unit volume of fuel, etc.)

[0046] Although each of the above state variables can be measured by providing an appropriate sensor, it is not realistic to measure all of the state variables in an actual engine 200 due to cost and installation constraints. Therefore, in this embodiment, only the rotation speed Ne and some of the air density measurement data used to improve the estimation accuracy in the state estimation unit 120 are measured, and the state estimation unit 120 calculates estimated values ​​for the other state variables.

[0047] The fuel supply amount U per combustion, which is the driving input to the engine 200, is set based on measurement data of the rotation speed Ne of the combustion section 210. That is, when the target rotation speed of the combustion section 210 is set to Ne0, the difference between the measured value Ne and the target value Ne0 is calculated, and the fuel supply amount U per combustion that reduces the difference is set based on a predetermined table or algorithm.

[0048] Next, a technique for improving the accuracy of state estimation using air density measurement data, which the present inventor discovered through experiments, will be described. Figs. 4 to 7 show the results of an experiment on the influence of the outside air temperature Ta, the outside air pressure Pa, and the cooling water temperature Tw, which are the air density measurement data, on various state variables of the engine 200. Specifically, Fig. 4 shows the influence on the output, Fig. 5 shows the influence on the fuel consumption, Fig. 6 shows the influence on the temperature near the outlet of the compressor 241 in the intake pipe 222 (compressor outlet temperature Tc), the scavenging temperature Ts in the intake receiver 223, and the exhaust temperature Tex in the exhaust receiver 231, and Fig. 7 shows the influence on the scavenging pressure Ps in the intake receiver 223, the exhaust pressure Pex in the exhaust receiver 231, and the pressure in the turbine outlet pipe 233 (turbine outlet pressure P0). In each experiment, measurements were performed while changing the load of the engine 200, and each figure shows the results when the load of the engine 200 was 50%, 75%, 85%, and 100% of the maximum load, respectively.

[0049] In each figure, the rate of change in the state variable of interest in each figure is shown as a graph when the outside air temperature Ta, the outside air pressure Pa, and the cooling water temperature Tw change within the assumed fluctuation range of the environmental conditions. For example, looking at the outside air temperature Ta in Figure 4, which is the output, there is an effect of about -1.2% at a load of 100%, which means that the output when the outside air temperature Ta is at the upper limit of the assumed range is about 1.2% lower than the output when the outside air temperature Ta is at the lower limit of the assumed range. Similarly, looking at the outside air temperature Ta in Figure 5, which is the fuel efficiency, there is an effect of about 1.5% at a load of 50%, which means that the fuel efficiency when the outside air temperature Ta is at the upper limit of the assumed range is about 1.5% higher than the fuel efficiency when the outside air temperature Ta is at the lower limit of the assumed range.

[0050] 4 and 5, which relate to the output and fuel economy that are important indices of the engine 200, it can be seen that, of the three air density measurement data, the outside air temperature Ta has a particularly large effect on the output and fuel economy. Therefore, by measuring the outside air temperature Ta at the sensor installation position S0 and supplying it to the state estimation unit 120 via the air density measurement data acquisition unit 110, the state estimation unit 120 can estimate the output and fuel economy with high accuracy.

[0051] According to FIG. 6 regarding the temperatures of the gas flowing through the engine 200, it can be seen that the outside air temperature Ta has the greatest effect on the compressor outlet temperature Tc (followed by the cooling water temperature Tw), the cooling water temperature Tw has the greatest effect on the scavenging temperature Ts, and the outside air temperature Ta has the greatest effect on the exhaust temperature Tex (followed by the cooling water temperature Tw). Also, according to FIG. 7 which relates to the pressure of gas circulating within the engine 200, it can be seen that the outside air temperature Ta has the greatest effect on the scavenging pressure Ps (followed by the cooling water temperature Tw), the outside air temperature Ta has the greatest effect on the exhaust pressure Pex (followed by the cooling water temperature Tw), and the outside air pressure Pa has the greatest effect on the turbine outlet pressure P0. Therefore, by measuring the outside air temperature Ta (sensor installation position S0), the outside air pressure Pa (sensor installation position S0), and the cooling water temperature Tw (sensor installation position S1) and supplying them to the state estimation unit 120 via the air density measurement data acquisition unit 110, the state estimation unit 120 can estimate with high accuracy the state variables that are greatly influenced by each air density measurement data.

[0052] Although the experiments were performed on three types of air density measurement data in the above, the suggestions obtained here can be applied to other types of air density measurement data as follows.

[0053] 4 and 5, the outside air temperature Ta had the greatest effect on the output and fuel efficiency, which is believed to be because the state of the outside air directly affects the basic operation of engine 200, i.e., the combustion of fuel and the generation of power in combustion section 210. In other words, since outside air is drawn into compressor 241 and supplied to combustion section 210, it is understood that the state of the outside air has a large effect on the output and fuel efficiency of engine 200.

[0054] On the other hand, the outside air pressure Pa, another parameter that indicates the outside air condition, has almost no effect on the output and fuel economy in Figures 4 and 5. This is thought to be because the outside air pressure Pa has almost no effect on the output and fuel economy within the expected range of fluctuations.

[0055] When the above-mentioned outside air is sucked and compressed by the compressor 241 and enters the intake pipe 222 and the intake receiver 223, the intake pressure Pb or the scavenging pressure Ps, which is the pressure, is considered to be the main parameter that affects the output and fuel efficiency. This is because the intake air temperature Tb or the scavenging air temperature Ts is cooled to within a certain range by the intake air cooler 224 provided in the intake pipe 222, and the density of the air supplied to the combustion section 210 is mainly determined by the pressure. Therefore, in the engine 200 provided with the intake air cooler 224, the intake air pressure Pb or the scavenging air pressure Ps of the cooled air is measured as air density measurement data and supplied to the state estimation section 120 via the air density measurement data acquisition section 110, so that the state estimation section 120 can estimate the output and fuel efficiency with high accuracy. On the other hand, in the engine 200 not provided with the intake air cooler 224, the intake air temperature Tb or the scavenging air temperature Ts is considered to continue to have a large effect on the output and fuel efficiency, similar to the outside air temperature Ta, so that the output and fuel efficiency can be estimated with high accuracy by measuring them.

[0056] In summary, in order to improve the accuracy of estimating the output and fuel efficiency, which are important indicators of the engine 200, it is preferable to use the following air density measurement data. Outside temperature Ta · Boost pressure Pb or scavenging pressure Ps Supply air temperature Tb or scavenging air temperature Ts (when the supply air cooler 224 is not provided)

[0057] The above-mentioned knowledge obtained from Figures 4 to 7 is preferably incorporated in advance as information representing the relationship between each air density measurement data and each state variable into the engine model of calculation unit 121. With such an engine model, it is possible to perform highly accurate calculation of each state variable in accordance with each measured air density measurement data, taking into account the degree of influence as shown in Figures 4 to 7.

[0058] 4 to 7, it can be seen that when the load of the engine 200 is low, such as 50% of the maximum load, the gas density measurement data tends to have a large effect on each state variable. This is believed to be because when the engine 200 is operating at a low load, it is easily affected by various changes inside and outside the engine 200. Therefore, it is preferable that the state estimation unit 120 estimates the state of the engine 200 using the gas density measurement data when the engine 200 is operating at a low load, for example, at a load of 50% or less of the maximum load. On the other hand, when the engine 200 is operating at a high load, when the effect of the gas density measurement data is relatively small, for example, when the engine 200 is operating at a load higher than 50% of the maximum load, state estimation may be performed without using the gas density measurement data, or the frequency of state estimation itself may be reduced.

[0059] The engine state estimation result output by the engine state estimating device 100 as described above can be used for the following purposes, for example. The engine state estimation result can be used for various controls of the engine 200. According to this embodiment, the accuracy of estimating the state of the engine 200 can be improved, and therefore the accuracy of control can also be improved accordingly. The engine state estimation result can be used for monitoring and deterioration diagnosis of the engine 200. An abnormality in the engine can be accurately identified and a quick response can be taken.

[0060] Fig. 8 is a schematic diagram showing the configuration of an engine state estimating device 100 according to the second embodiment. The engine state estimating device 100 according to the first embodiment shown in Fig. 1 differs only in the configuration of a state estimating unit 120. The state estimating unit 120 includes a calculating unit 121 and an engine model correcting unit 122.

[0061] The calculation unit 121 uses the fuel supply amount U and the revolution speed Ne as input data, calculates an estimate of the state variables of the engine 200 based on an engine model that represents the characteristics of the engine 200, and outputs the result as an engine state estimation result. In this embodiment, unlike the first embodiment, the air density measurement data is not input to the engine model of the calculation unit 121, but is supplied to the subsequent engine model correction unit 122. Instead, the calculation unit 121 calculates air density estimation data, which is an estimate of the gas density measurement data, in the calculation based on the above engine model. As described in the first embodiment, the measurement data that affect the air density, such as the outside air pressure Pa, the outside air temperature Ta, the supply air pressure Pb / scavenging air pressure Ps, the supply air temperature Tb / scavenging air temperature Ts, and the cooling water temperature Tw, are all state variables of the engine 200, so the calculation unit 121 can obtain the gas estimation data in the normal calculation for obtaining the engine state estimation result.

[0062] The engine model correction unit 122 corrects the engine model in the calculation unit 121 so that the difference between the air density estimation data supplied from the calculation unit 121 and the air density measurement data supplied from the air density measurement data acquisition unit 110 becomes small. Here, if there is a difference between the air density estimation data, which is an estimated value, and the air density measurement data, which is an actual measurement value, the engine model on which the estimated value was calculated deviates from the characteristics of the actual engine 200, so the engine model is corrected by the engine model correction unit 122 to approach the characteristics of the actual engine 200. Ideally, if the difference between the air density estimation data and the air density measurement data is always zero, the engine model will accurately represent the characteristics of the actual engine 200. Such a correction allows the engine model to better reflect the characteristics of the actual engine 200, so that the accuracy of engine state estimation can be improved. Particularly in this embodiment, the engine model can be effectively corrected by using the air density measurement data, which has a large influence on each state variable such as the output and fuel efficiency of the engine 200.

[0063] The present invention has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present invention.

[0064] In the embodiment, the temperature or pressure is exemplified as the air density measurement data, but other parameters related to the air density may be measured. For example, the concentration, density, and amount of components of a gas may be measured.

[0065] The functional configuration of each device described in the embodiment can be realized by hardware resources, software resources, or by the cooperation of hardware resources and software resources. A processor, ROM, RAM, and other LSIs can be used as hardware resources. An operating system, an application, and other programs can be used as software resources.

[0066] Among the embodiments disclosed in this specification, those in which multiple functions are provided in a distributed manner may have some or all of the multiple functions integrated together, and conversely, those in which multiple functions are provided in a distributed manner may have some or all of the multiple functions integrated together. Regardless of whether the functions are integrated or distributed, it is sufficient that the configuration is such that the object of the invention can be achieved. [Explanation of symbols]

[0067] 100 engine state estimation device, 110 air density measurement data acquisition section, 120 state estimation section, 121 calculation section, 122 engine model correction section, 200 engine, 210 combustion section, 220 air intake passage, 221 intake pipe, 222 air intake pipe, 223 air intake receiver, 224 air intake cooler, 230 exhaust passage, 231 exhaust receiver, 232 exhaust pipe, 233 turbine outlet pipe, 240 supercharger, 241 compressor, 242 turbine.

Claims

1. An engine state estimation device that estimates a state of an engine including a combustion section that generates power by combusting air and fuel, and a supercharger that increases the pressure of intake air and supplies the air to the combustion section, an air density measurement data acquisition unit that acquires measurement data of parameters related to at least one density of the air taken in by the turbocharger and the compressed air supplied to the combustion section by the turbocharger; a state estimation unit that estimates a state of the engine based on the air density measurement data and an amount of fuel supplied to the combustion unit that is input to an engine model that represents characteristics of the engine; Equipped with The state estimation unit is a calculation unit that calculates air density estimation data, which is an estimate of the air density measurement data, based on the fuel supply amount input to the engine model; an engine model correction unit that corrects the engine model so that a difference between the air density estimation data and the air density measurement data that is not input to the engine model becomes small; An engine state estimating device comprising:

2. The engine is a marine engine having a rated speed of 1000 rpm or less. The engine state estimating device according to claim 1 .

3. The state estimation unit inputs the air density measurement data into the engine model to estimate the state of the engine. The engine state estimating device according to claim 1 or 2.

4. The measuring device for the air density measurement data is provided in an intake pipe through which the air taken in by the supercharger flows. The engine state estimating device according to any one of claims 1 to 3.

5. The air density measurement data measuring device is provided in an air supply housing that houses the compressed air. The engine state estimating device according to any one of claims 1 to 4.

6. The air density measurement data is at least one of the temperature and pressure of the air taken in by the turbocharger and the compressed air. The engine state estimating device according to any one of claims 1 to 5.

7. The air density measurement data is measurement data of the temperature of the air taken in by the turbocharger. The engine state estimating device according to claim 6.

8. The engine includes a cooler that cools the compressed air, The air density measurement data is measurement data of the pressure of the compressed air cooled by the cooler. The engine state estimating device according to claim 6 or 7.

9. The engine includes a cooler that cools the compressed air, The air density measurement data is measurement data of the temperature of the cooling medium of the cooler. The engine state estimating device according to any one of claims 1 to 8.

10. The state estimation unit estimates a state of the engine based on measurement data of a rotation speed of a rotation drive unit that generates rotational power in the combustion unit. The engine state estimating device according to any one of claims 1 to 9.

11. The state estimation unit estimates the state of the engine when the load of the engine is 50% or less of its maximum load. The engine state estimating device according to any one of claims 1 to 10.

12. 1. An engine state estimation method for estimating a state of an engine including a combustion section that generates power by combusting air and fuel, and a supercharger that increases the pressure of intake air and supplies the air to the combustion section, comprising: an air density measurement data acquisition step of acquiring measurement data of parameters related to at least one density of the air taken in by the turbocharger and the compressed air supplied by the turbocharger to the combustion section; a state estimating step of estimating a state of the engine based on the air density measurement data and an amount of fuel supplied to the combustion section that is input to an engine model representing characteristics of the engine; Equipped with The state estimation step includes: a calculation step of calculating air density estimation data, which is an estimate of the air density measurement data, based on the fuel supply amount input to the engine model; an engine model correcting step of correcting the engine model so that a difference between the air density estimation data and the air density measurement data that is not input to the engine model is reduced; An engine state estimation method comprising:

13. An engine state estimation program for estimating a state of an engine having a combustion unit that generates power by combusting air and fuel, and a supercharger that increases the pressure of intake air and supplies the air to the combustion unit, an air density measurement data acquisition step of acquiring measurement data of parameters related to at least one density of the air taken in by the turbocharger and the compressed air supplied by the turbocharger to the combustion section; a state estimating step of estimating a state of the engine based on the air density measurement data and an amount of fuel supplied to the combustion section that is input to an engine model representing characteristics of the engine; on the computer, The state estimation step includes: a calculation step of calculating air density estimation data, which is an estimate of the air density measurement data, based on the fuel supply amount input to the engine model; an engine model correcting step of correcting the engine model so that a difference between the air density estimation data and the air density measurement data that is not input to the engine model is reduced; An engine state estimation program comprising:

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