Engine characteristic estimation device, engine characteristic estimation method, engine characteristic estimation program, and engine state estimation device

Abstract

To provide an engine characteristic estimation device capable of highly accurately estimating change of characteristics of an engine.SOLUTION: An engine characteristic estimation device 100 includes: a first calculation section calculating a first engine state parameter X1 on the basis of a first calculation model and fuel supply amount to an engine 200; a second calculation section calculating a second engine state parameter X2 on the basis of a second calculation model and operation data of the engine 200; and an engine characteristic estimation section 130 estimating characteristics of the engine 200 on the basis of the first engine state parameter X1 and the second engine state parameter X2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an engine characteristic estimation technique and a state estimation technique.

Background Art

[0002] Engines are widely used in ships, automobiles, aircraft, etc. However, due to the increasing awareness of environmental problems, further improvement in efficiency has been demanded in recent years. In order to improve the efficiency of an engine, it is necessary to accurately estimate the state of the engine and optimally control the engine based on the estimation result.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 discloses a technique for estimating the state of an engine by a state observer. The state observer uses a matrix representing the characteristics of the engine and calculates parameters representing the state of the engine from various measurement data of the engine. In this calculation, when the matrix accurately represents the characteristics of the engine, the state parameters of the engine can be calculated with high accuracy. On the other hand, when the characteristics of the engine change due to aging deterioration or changes in the external environment such as intake air temperature, the matrix no longer accurately reflects the characteristics of the engine, so the estimation accuracy of the state of the engine decreases.

[0005] The present invention has been made in view of such a situation, and its object is that the characteristics of the engine The present invention aims to provide an engine characteristic estimation device that can estimate changes in engine characteristics with high accuracy. Another object of the present invention is to provide an engine condition estimation device that can estimate the state of the engine with high accuracy. [Means for solving the problem]

[0006] To solve the above problems, an engine characteristic estimation device according to one aspect of the present invention comprises: a first calculation unit that calculates a first engine state parameter, which is an engine state variable, based on a first calculation model representing the characteristics of an engine and the amount of fuel supplied to the engine at any given time; a second calculation unit that calculates a second engine state parameter, which is an engine state variable, based on a second calculation model different from the first calculation model representing the characteristics of an engine and operation data relating to the operation of the engine being driven at any given time; and an engine characteristic estimation unit that estimates the characteristics of an engine at any given time based on the first engine state parameter and the second engine state parameter.

[0007] In this embodiment, the fuel supply amount used in the calculations of the first calculation unit is data that is not affected by changes in engine characteristics due to aging or changes in the external environment such as intake air temperature. Therefore, the first engine state parameter, which is the result of its calculation, is not affected by changes in engine characteristics. In contrast, the engine operation data used in the calculations of the second calculation unit is data that is affected by changes in engine characteristics. Therefore, the second engine state parameter, which is the result of its calculation, is affected by changes in engine characteristics. By using two types of engine state parameters that are affected by changes in engine characteristics in this way, the engine characteristic estimation unit can estimate changes in engine characteristics with high accuracy. Furthermore, even when there are no changes in engine characteristics, the state of the engine can be estimated with high accuracy by using two calculation units with different calculation models in combination.

[0008] Another aspect of the present invention is an engine characteristic estimation method. This method comprises: a first calculation step of calculating a first engine state parameter, which is an engine state variable, based on a first calculation model representing the characteristics of an engine and the amount of fuel supplied to the engine at any given time; a second calculation step of calculating a second engine state parameter, which is an engine state variable, based on a second calculation model different from the first calculation model representing the characteristics of an engine and operation data relating to the operation of the engine being driven at any given time; and an engine characteristic estimation step of estimating the characteristics of an engine at any given time based on the first engine state parameter and the second engine state parameter.

[0009] Another aspect of the present invention is an engine state estimation device. This device comprises: a first calculation unit that calculates a first engine state parameter, which is an engine state variable, based on a first calculation model representing the characteristics of an engine and the amount of fuel supplied to the engine at any given time; a second calculation unit that calculates a second engine state parameter, which is an engine state variable, based on a second calculation model different from the first calculation model representing the characteristics of an engine and operation data relating to the operation of the engine being driven at any given time; and an engine state estimation unit that estimates the state of the engine at any given time based on the first engine state parameter and the second engine state parameter.

[0010] According to this embodiment, the engine state can be estimated with high accuracy by using two calculation units with different calculation models in combination.

[0011] Furthermore, any combination of the above components, as well as conversions of the expression of the present invention between methods, apparatus, systems, recording media, computer programs, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0012] According to the present invention, even if the characteristics of the engine change, they can be estimated with high accuracy. Furthermore, the state of the engine can be estimated with high accuracy. [Brief explanation of the drawing]

[0013] [Figure 1] This diagram shows the overall configuration of the engine characteristic estimation device according to the embodiment. [Figure 2] This is a diagram showing the engine configuration. [Figure 3] This diagram shows the configuration of other engines. [Figure 4] This diagram shows the configuration of the simulator and observer. [Figure 5] This diagram shows the configuration of the engine characteristic estimation unit. [Figure 6] This flowchart shows the processing flow for engine characteristic estimation using an engine characteristic estimation device. [Figure 7] This is a schematic diagram illustrating an example of engine characteristic estimation using an engine characteristic estimation device. [Modes for carrying out the invention]

[0014] Figure 1 is a schematic diagram showing the overall configuration of the engine characteristic estimation device 100 according to this embodiment. First, the engine 200, which is the target of characteristic estimation by the engine characteristic estimation device 100, is driven by the supply of an amount of fuel specified by the fuel supply amount U per combustion, and generates power. Then, the state parameter X0, which is a state variable of the engine 200, changes according to its operating state. Here, X0 is a vector containing multiple parameters (with n being a natural number of 2 or more as the number of parameters, each parameter is represented as X01, X02, ..., X0n). ​​What to select as the state parameter X0 of the engine 200 can be appropriately determined according to the control target and specifications of the engine system, but typically it is preferable to select the engine speed, exhaust pressure, exhaust temperature, displacement, etc. Furthermore, if a supercharger that increases the pressure of the air flowing into the engine is used, it is preferable to include the parameters of the supercharger, such as speed, intake air temperature, intake air pressure, intake air volume, scavenging air temperature, scavenging air pressure, scavenging air volume, etc., in the state parameter X0.

[0015] In the engine characteristic estimation of the present embodiment, it is important to focus on the state parameter X0 inside the engine 200 rather than the power generated by the engine 200 for the outside. Therefore, the engine 200 is illustrated as a block that outputs the state parameter X0 based on the input of the fuel supply amount U per combustion.

[0016] The engine characteristic estimation device 100 is a device that estimates the characteristics of the engine 200, and includes a simulator 110 as a first calculation unit, an observer 120 as a second calculation unit, an engine characteristic estimation unit 130, a calculation model update unit 140, and a calculation model update mode execution unit 150.

[0017] The simulator 110 calculates a first engine state parameter X1, which is a state variable of the engine 200, based on a first calculation model representing the characteristics of the engine 200 and the fuel supply amount U per combustion supplied to the engine 200 at an arbitrary time point. Here, X1 is a vector including a plurality of parameters (the number of parameters is n, the same as the state parameter X0, and each parameter is X11, X12,..., X1n).

[0018] The observer 120 calculates a second engine state parameter X2, which is a state variable of the engine 200, based on a second calculation model different from the first calculation model representing the characteristics of the engine 200, operation data X0' regarding the operation of the engine 200 being driven at an arbitrary time point, and the fuel supply amount U per combustion. Here, X2 is a vector including a plurality of parameters (the number of parameters is n, the same as the state parameter X0, and the elements of the vector are X21, X22,..., X2n).

[0019] The operation data X0´, which is input to the observer 120, is a part (one or more and less than n) of the state parameters included in the state parameters X0 of the engine 200. In the actual engine 200, it is not realistic to provide sensors for measuring all n parameters included in the state parameters X0 due to cost and installation constraints. Therefore, only some of the parameters X0´ are measured and used as the input to the observer 120. The basic function of the observer 120 is to complement some of the parameters X0´ and estimate all the state parameters X2.

[0020] The engine characteristic estimation unit 130 estimates the characteristics of the engine 200 at an arbitrary time based on the first engine state parameter X1 and the second engine state parameter X2. Specifically, it calculates the difference between the first engine state parameter X1 and the second engine state parameter X2, and estimates the characteristics of the engine 200 based on this difference.

[0021] The calculation model update unit 140 updates the second calculation model of the observer 120 based on the characteristics of the engine 200 estimated by the engine characteristic estimation unit 130. The calculation model update mode execution unit 150 executes an update mode for updating the second calculation model by the calculation model update unit 140.

[0022] Subsequently, each of the above configurations will be described in more detail with reference to other figures. FIG. 2 is a schematic diagram showing the configuration of the engine 200. In the present embodiment, the use of the engine 200 is not limited, and various engines 200 such as marine engines, vehicle engines, and aircraft engines can be used. The engine 200 includes an engine body 210 that generates power by burning fuel, an intake passage 220 that supplies air for burning fuel to the engine body 210, an exhaust passage 230 that discharges the gas after combustion in the engine body 210, and a supercharger 240 that increases the pressure of the air supplied to the engine body 210 through the intake passage 220.

[0023] The engine body 210 includes a combustion chamber 211 where combustion of fuel with air occurs, a fuel supply nozzle 212 that supplies an amount of fuel specified by the fuel supply amount U per combustion into the combustion chamber 211, an intake valve 213 that controls the supply of air from the intake passage 220 to the combustion chamber 211, an exhaust valve 214 that controls the discharge of air from the combustion chamber 211 to the exhaust passage 230, a piston 215 that is driven linearly in accordance with the combustion of fuel in the combustion chamber 211, a crankshaft 216 that is rotationally driven in accordance with the linear motion of the piston 215, and a connecting rod 217 that is fixed at one end to the piston 215 and at the other end to the crankshaft 216 and converts the linear motion of the piston 215 into the rotational motion of the crankshaft 216. In the above configuration, fuel is supplied directly into the combustion chamber 211 by the fuel supply nozzle 212. However, when using highly volatile fuels such as gasoline, the fuel may be injected into the intake passage 220 and supplied to the combustion chamber 211 in a mixed state with air.

[0024] In the above configuration, the engine 200 is driven in the following cycle. Here, the engine 200 is assumed to be in operation due to the drive in the previous cycle, and the piston 215 repeatedly moves up and down in accordance with the movement of the crankshaft 216, which continues to rotate due to inertia.

[0025] (1) Intake: The intake valve 213 opens, the exhaust valve 214 closes, and the piston 215 descends, supplying air from the intake passage 220 to the combustion chamber 211. (2) Compression: The intake valve 213 closes and the piston 215 rises, compressing the air in the combustion chamber 211. (3) Combustion: A fuel supply nozzle 212 supplies an amount of fuel specified by the fuel supply amount U per combustion into the combustion chamber 211, which is burned together with compressed air. This generates power, causing the piston 215 to descend. (4) Exhaust: The exhaust valve 214 opens and the piston 215 rises, causing the combustion gas to be discharged from the combustion chamber 211 into the exhaust passage 230.

[0026] The supercharger 240 is a so-called turbocharger and comprises a compressor 241 located in the intake passage 220, a turbine 242 located in the exhaust passage 230, and a shaft 243 that coaxially connects the compressor 241 and the turbine 242. The gas discharged from the exhaust passage 230 rotates the turbine 242, and this rotation is transmitted to the compressor 241 via the shaft 243. As the compressor 241 rotates in this manner, the air supplied to the intake passage 220 is compressed, thereby increasing the pressure of the air supplied to the combustion chamber 211.

[0027] In Figure 2, a so-called four-stroke engine, which consists of four strokes—(1) intake, (2) compression, (3) combustion, and (4) exhaust—is used as an example. However, in this embodiment, the type of engine is not limited to this, and various types of engines can be used. For example, a so-called two-stroke engine, as shown in Figure 3, can be used (the same reference numerals are used for components corresponding to those in Figure 2).

[0028] The engine body 210 of a two-stroke engine, like the four-stroke engine described above, drives the piston 215 in a straight line by the combustion of fuel in the combustion chamber 211, and converts that into rotational power for the crankshaft 216. The main structure of both types of engines is almost the same, but one difference in the two-stroke engine is that the engine body 210 has a scavenging passage 219 that connects the crankcase 218, which houses the crankshaft 216, to the combustion chamber 211.

[0029] In the illustrated state where the piston 215 is descending, the path through the crankcase 218, scavenging passage 219, combustion chamber 211, and exhaust passage 230 is open to gas flow. Fresh air from the crankcase 218 flows into the combustion chamber 211 through the scavenging passage 219, and with that force, the burnt gas is discharged into the exhaust passage 230 (scavenging).

[0030] Subsequently, as the piston 215 rises, it closes the scavenging passage 219 and the exhaust passage 230, sealing the combustion chamber 211 and increasing its pressure. Then, fuel is supplied from the fuel supply nozzle 212 into the high-pressure combustion chamber 211, triggering combustion and generating the power to bring the piston 215 down again. Meanwhile, as the piston 215 rises, the crankcase 218 and the intake passage 220 communicate, and fresh air flows from the intake passage 220 into the crankcase 218. In this way, when the piston 215 rises, combustion in the combustion chamber 211 and intake in the crankcase 218 occur simultaneously.

[0031] As described above, in a two-stroke engine, one cycle is completed in a total of two strokes: one downward movement and one upward movement of the piston 215. In such a two-stroke engine, using the supercharger 240 shown in Figure 2 can increase the intake pressure into the crankcase 218 when the piston 215 is rising, and the scavenging pressure into the combustion chamber 211 when the piston 215 is descending.

[0032] Furthermore, as a two-stroke engine, one having a scavenging receiver for containing scavenging air, as disclosed in Patent Document 2, may be used. In this case, similar to the above explanation of scavenging with respect to Figure 3, when the piston (41: reference numeral in Patent Document 2 (hereinafter the same)) is in a downward position, the path passing through the scavenging receiver (2), the crankcase 218 and the scavenging port (17) corresponding to the scavenging passage 219, the cylinder (1) corresponding to the combustion chamber 211, and the exhaust duct (6) corresponding to the exhaust passage 230 is open to gas flow. Fresh air in the scavenging receiver flows into the cylinder through the scavenging port, and the scavenging operation is performed by using that force to discharge the burnt gas into the exhaust duct. In addition, if a supercharger 240 is used in such a configuration, the scavenging pressure in the scavenging receiver can be increased.

[0033] As described above, this embodiment can be applied to various types of engines 200, but it is particularly suitable for use with marine engines with a rated rotational speed of 1000 revolutions per minute or less. Generally, marine engines are driven at lower rated rotational speeds compared to vehicle engines. Furthermore, especially in large vessels, it takes time for the power generated by the engine to be reflected in the actual movement of the vessel, so accurate engine operation is required. Thus, in marine engines, there is a high demand for accurate operation by estimating changes in engine characteristics and conditions with high precision, and it is preferable to use the engine characteristic estimation device 100 of this embodiment.

[0034] Here, the following are examples of engine characteristics 200 that are estimated by the engine characteristic estimation device 100. • Combustion efficiency: The efficiency of combustion in the combustion chamber 211. Also called thermal efficiency. • Power transmission efficiency: The ratio of the effective torque (calculated by subtracting losses in each mechanical part) to the torque generated by the engine body 210. Also called mechanical transmission efficiency. • Dynamic characteristics: Relationships between multiple parameters considering time. For example, the response of pressure to temperature changes. • Efficiency of supercharger 240: Efficiency of compressor 241, efficiency of turbine 242, etc. • External disturbances: Temperature (atmospheric air temperature) and pressure (atmospheric pressure) of the outside air inhaled by the engine 200, and in the case of marine engines, loads such as waves entering from the propeller that is being driven. Furthermore, the above-mentioned disturbances are important as they significantly affect the actual operation of the engine 200, and in the mathematical model described later with respect to Figure 4, they can be treated the same as other characteristics.

[0035] In the engine 200 described above with examples, the state parameters X0 used for characteristic estimation and control can be composed of, for example, the following parameters.

[0036] Parameters related to the operation of the engine body 210: • Crankshaft rotation speed 216 (Engine body rotation speed 210 Ne) • Temperature of the gas discharged from the exhaust passage 230 (exhaust temperature Tex of the engine body 210) • Pressure of the gas discharged from the exhaust passage 230 (exhaust pressure Pex of the engine body 210) • Flow rate of gas discharged from exhaust passage 230 (engine body 210 displacement Gex)

[0037] Parameters related to the operation of supercharger 240: • Rotational speeds of compressor 241, turbine 242, and shaft 243 (rotational speed Ntc of supercharger 240) • In a 4-stroke engine such as the one shown in Figure 2, which does not perform scavenging, the temperature of the air supplied from the intake passage 220 to the combustion chamber 211 via the supercharger 240 (intake temperature Tb of the supercharger 240) In a four-stroke engine, such as the one shown in Figure 2, which does not perform scavenging, the pressure of the air supplied from the intake passage 220 to the combustion chamber 211 via the supercharger 240 (intake pressure Pb of the supercharger 240) • In a 4-stroke engine, such as the one shown in Figure 2, which does not perform scavenging, the flow rate of air supplied from the intake passage 220 to the combustion chamber 211 via the supercharger 240 (air intake volume Gb of the supercharger 240) In a two-stroke engine performing a scavenging operation, such as those shown in Figure 3 and Patent Document 2, the pressure of the air supplied from the scavenging passage 219 to the combustion chamber 211 and the temperature of the air in the scavenging receiver (scavenging temperature Ts of the supercharger 240) In a two-stroke engine performing a scavenging operation, such as those shown in Figure 3 and Patent Document 2, the pressure of the air supplied from the scavenging passage 219 to the combustion chamber 211 and the pressure of the air in the scavenging receiver (scavenging pressure Ps of the supercharger 240) In a two-stroke engine performing a scavenging operation, such as those shown in Figure 3 and Patent Document 2, the pressure of the air supplied from the scavenging passage 219 to the combustion chamber 211 and the flow rate of air in the scavenging receiver (scavenging amount Gs of the supercharger 240)

[0038] If a supercharger 240 is not provided, the supply of air to the combustion chamber 211 (in the case of a 4-stroke engine) and the scavenging of air to the combustion chamber 211 (in the case of a 2-stroke engine) are the operations of the engine body 210. Therefore, the above-mentioned supply air temperature Tb, supply pressure Pb, supply air volume Gb, scavenging air temperature Ts, scavenging pressure Ps, and scavenging air volume Gs are parameters related to the operation of the engine body 210.

[0039] Each of the above parameters can be measured by installing a suitable sensor, but in an actual engine 200, it is not practical to measure all parameters due to cost and installation constraints, and some parameters X0' are measured and input to the observer 120. The selection of parameters X0' to be measured can be appropriately determined according to the control goals and specifications of the engine system, but it is preferable to select them according to the following criteria, for example.

[0040] At least one parameter is measured from the parameters related to the operation of the engine body 210 (engine body data) and the parameters related to the operation of the supercharger 240 (supercharger data). Examples of engine body data include the rotational speed Ne, exhaust temperature Tex, exhaust pressure Pex, and displacement Gex listed above. Examples of supercharger data include the rotational speed Ntc, intake air temperature Tb (for 4-stroke engines), intake pressure Pb (same as above), intake air volume Gb (same as above), scavenging air temperature Ts (for 2-stroke engines), scavenging pressure Ps (same as above), and scavenging air volume Gs (same as above). By selecting the parameters to be measured in this way, the observer 120 can estimate the overall system state of the engine 200 with high accuracy based on the measurement data of the engine body 210 and the supercharger 240.

[0041] As other criteria, at least one parameter is measured from the parameters relating to the mechanical operation of the engine 200 (mechanical data) and the parameters relating to the thermodynamic state of the engine 200 (thermodynamic data). Examples of mechanical data include the rotational speed Ne of the engine body 210 and the rotational speed Ntc of the supercharger 240, as listed above. Examples of thermodynamic data include the exhaust temperature Tex, exhaust pressure Pex, displacement Gex, intake air temperature Tb (for a 4-stroke engine), intake pressure Pb (same as above), intake air volume Gb (same as above), scavenging air temperature Ts (for a 2-stroke engine), scavenging pressure Ps (same as above), and scavenging air volume Gs (same as above). By selecting the parameters to be measured in this way, the observer 120 can estimate the state of the engine 200 with high accuracy, taking into account the mechanical and thermodynamic aspects, based on the measured mechanical and thermodynamic data.

[0042] In actual design, it is best to select measurement parameters that satisfy both of the above criteria simultaneously. For example, the rotational speed Ne of the engine body 210 and the scavenging pressure Ps of the supercharger 240 should be selected as measurement parameters. Here, rotational speed Ne is engine body data and mechanical data, and scavenging pressure Ps is supercharger data and thermodynamic data, thus satisfying both of the above criteria simultaneously.

[0043] The fuel supply amount U per combustion, which is the drive input to the engine 200, is set based on the measured data of the rotational speed Ne of the engine body 210. That is, when the target rotational speed of the engine body 210 is Ne0, the difference between the measured value Ne and the target value Ne0 is calculated, and the fuel supply amount U per combustion is set based on a predetermined table or algorithm so as to minimize this difference.

[0044] Next, with reference to Figure 4, the configuration of the simulator 110 and the observer 120 will be explained.

[0045] The simulator 110 takes the amount of fuel supplied per combustion to the engine 200, U, as input and calculates a first engine state parameter X1 = (X11, X12, ..., X1n) as a vector with n elements, based on a first calculation model. Here, the number of elements in the first engine state parameter X1 and the state parameter X0 of the engine 200 are equal, and each element of X1 is an estimate of each element of X0. For example, if the first element X01 of the state parameter X0 of the engine 200 is rotational speed Ne and the second element X02 is scavenging pressure Ps, then the first element X11 of the first engine state parameter X1 is an estimate of rotational speed Ne, and the second element X12 is an estimate of scavenging pressure Ps.

[0046] The first calculation model of the simulator 110 represents the characteristics of the engine 200 at a predetermined reference point, and simulates the state parameter X0 of the engine 200 at that reference point. Here, when setting the first calculation model, it is assumed that the engine 200 is in an ideal state without disturbances, so the first engine state parameter X1 as a calculation result represents the ideal state parameter X0 of the engine 200 at the reference point. Typically, the initial state of the engine 200 is selected as the reference point that defines the first calculation model. In this case, the first engine state parameter X1 simulates the ideal state parameter X0 of an ideal engine 200 that has not deteriorated in characteristics from its initial state and is placed in a state without disturbances.

[0047] Next, we will describe the state-space representation of engine 200 and the observer 120 that has a corresponding state-space representation. In Figure 4, engine 200 is assumed to be a linear system defined by the system coefficient matrix A. Specifically, the state of engine 200 is described by the following equation.

[0048] dX0 / dt = A·X0 + B·U X0'=C·X0 Here, each parameter represents the following: U: Fuel supply amount to engine 200 X0: Engine 200 status parameters X0': Input to Observer 120 (As mentioned above, this measures some of the operating parameters included in the state parameter X0) A: System coefficient matrix of Engine 200 Input vector B:U to input to the system Output vector extracted from C:X0 to X0' Furthermore, the state-space representation of engine 200 shown in the diagram is based on the above equation. ru.

[0049] Observer 120 has a state-space representation similar to that of engine 200. That is, observer 120 has the same system coefficient matrix A, input vector B, and output vector C as engine 200. The main difference from engine 200 is that the operation data X0' of engine 200 is input to observer 120 via observer gain H. Thus, observer 120 has a second computational model defined by the system coefficient matrix A and observer gain H, and calculates a second engine state parameter X2 using the fuel supply amount U per combustion and the operation data X0' as input.

[0050] The second engine state parameter X2 is a vector with n elements (X21, X22, ..., X2n). Similar to the first engine state parameter X1 described above, the number of elements in the second engine state parameter X2 is the same as that of the engine 200 state parameter X0, and each element of X2 is an estimate of each element of X0. For example, if the first element X01 of the engine 200 state parameter X0 is rotational speed Ne and the second element X02 is scavenging pressure Ps, then the first element X21 of the second engine state parameter X2 is an estimate of rotational speed Ne, and the second element X22 is an estimate of scavenging pressure Ps.

[0051] Unlike the simulator 110, which calculates ideal state parameters X1 at a certain reference point, the observer 120 calculates real-time state parameters X2 of the engine 200. While the observer 120 is unnecessary if all state parameters X0 of the engine 200 are measured, measuring all parameters is impractical, so the observer 120 is used to estimate the state parameters X2.

[0052] Although the above explanation used the example of engine 200 being a linear system, the observer 120 can be similarly constructed for nonlinear systems. In other words, the observer 120 only needs to include elements representing the system characteristics of engine 200 (the system coefficient matrix in the example of Figure 4) in the second calculation model, and whether engine 200 is a linear or nonlinear system is not essential in this embodiment.

[0053] Figure 5 is a schematic diagram showing the configuration of the engine characteristic estimation unit 130. The engine characteristic estimation unit 130 comprises a difference calculation unit 131, an absolute value calculation unit 132, a weighting calculation unit 133, an addition unit 134, and a threshold comparison unit 135, and the difference calculation result from the difference calculation unit 131 is used as the characteristic estimation output of the engine 200.

[0054] The difference calculation unit 131 calculates the difference between the first engine state parameter X1 and the second engine state parameter X2. Specifically, it has a number of differencers 131-1, 131-2, ..., 131-n equal to the number of elements n of X1 and X2. Each differencer calculates the difference e1, e2, ..., en of the corresponding parameters of X1 and X2. As in the example above, if the first element X01 of the state parameter X0 is rotational speed Ne and the second element X02 is scavenging pressure Ps, the first differencer 131-1 calculates the difference e1 between X11 and X21, which are estimated values ​​of rotational speed Ne, respectively, and the second differencer 131-2 calculates the difference e2 between X12 and X22, which are estimated values ​​of scavenging pressure Ps, respectively. These difference calculation results e1, e2, ..., en are supplied to the subsequent calculation model update unit 140 as the characteristic estimation output of the engine 200.

[0055] The absolute value calculation unit 132, the weighting calculation unit 133, the addition unit 134, and the threshold comparison unit 135 trigger the calculation model update process in the subsequent calculation model update unit 140 according to the results of this series of calculations. The absolute value calculation unit 132 calculates the absolute values ​​of the differences e1, e2, ..., en from the difference calculation unit 131.

[0056] The weighting calculation unit 133 multiplies the n calculation results from the absolute value calculation unit 132 by predetermined weights w1, w2, ..., wn. Here, each weight is appropriately set according to the importance of each parameter in the engine characteristic estimation in this embodiment. For example, in the above example, if the first parameter, rotational speed Ne, is given more importance than the second parameter, scavenging pressure Ps, in the engine characteristic estimation, the first weight w1 should be set to be larger than the second weight.

[0057] The addition unit 134 adds the n calculation results from the weighting calculation unit 133. The threshold comparison unit 135 compares the calculation result from the addition unit 134 with a predetermined threshold. If the calculation result from the addition unit 134 exceeds the threshold, it generates a trigger signal T for the calculation model update process in the subsequent calculation model update unit 140.

[0058] As described above, a trigger signal T is generated for the calculation model update unit 140 only when a predetermined criterion is met with respect to the differences e1, e2, ..., en from the difference calculation unit 131. This prevents the frequency of calculation model update processing from becoming too high and improves system stability. The threshold comparison unit 135 can also be configured to generate a trigger signal T when the calculation result from the addition unit 134 exceeds a threshold for a predetermined period of time. In this case, the trigger signal T will not be generated by momentary abnormal values, further improving system stability.

[0059] The above-described configuration of absolute value calculation unit 132, weighting calculation unit 133, addition unit 134, and threshold comparison unit 135 is merely an example. Various configurations can be adopted as long as they generate a trigger signal T to the calculation model update unit 140 based on the difference calculation results e1, e2, ..., en from the difference calculation unit 131. For example, if only one difference calculation result (e.g., e2) is important among multiple difference calculation results, the trigger signal T may be generated based only on its magnitude without considering the other difference calculation results. In this case, there is no need to provide the weighting calculation unit 133 or the addition unit 134.

[0060] Returning to Figure 1, the calculation model update unit 140 receives a trigger signal T from the engine characteristic estimation unit 130 and updates the second calculation model of the observer 120 based on a predetermined algorithm, taking the characteristic estimation outputs e1, e2, ..., en from the engine characteristic estimation unit 130 as input. As explained in Figure 4, the second calculation model is a calculation model that includes a system coefficient matrix A and an observer gain H. Here, the calculation model update unit 140 updates at least one of the system coefficient matrix A and the observer gain H based on a predetermined algorithm. Since the system coefficient matrix A, which is a matrix, and the observer gain H, which is a vector, each have multiple elements, it is sufficient to update at least one of their elements.

[0061] In particular, when dealing with changes in characteristics due to aging of engine 200 or changes in external environmental factors such as intake air temperature, it is preferable to update the system coefficient matrix A. If the characteristics of engine 200 have changed, that is, if the combustion efficiency, power transmission efficiency, dynamic characteristics, supercharger efficiency, disturbance effects, etc., as exemplified above have changed, then the system coefficient matrix A of engine 200 in Figure 4 has changed, and the system coefficient matrix A of observer 120 should be updated to match that change. As a result, the second calculation model of observer 120 will reflect the characteristics of engine 200, thereby improving the accuracy of engine 200 state estimation by observer 120.

[0062] The algorithm used in the calculation model update process by the calculation model update unit 140 can be appropriately designed with the goal of better reflecting the characteristics of the actual engine 200 in the second calculation model of the observer 120. A simple example is the following trial-and-error algorithm. In this algorithm, several pre-prepared update process options are tried sequentially, and the option that best improves the characteristic estimation outputs e1, e2, ..., en is adopted. Furthermore, the algorithm is not limited to a pre-programmed one, but may also be updateable by machine learning in response to actual processing results.

[0063] The calculation model update mode execution unit 150 executes an update mode for updating the second calculation model by the calculation model update unit 140. When the update mode is not executed, the calculation model update unit 140 does not update the second calculation model even if a trigger signal T is generated from the engine characteristic estimation unit 130. On the other hand, when the update mode is executed and a trigger signal T is generated from the engine characteristic estimation unit 130, the calculation model update unit 140 updates the second calculation model based on the characteristic estimation outputs e1, e2, ..., en. The update mode can be executed based on user operation or automatically at a predetermined frequency. By providing such a dedicated update mode, it is possible to prevent the frequency of calculation model update processing from becoming too high and to improve the stability of the system. On the other hand, it is of course possible to configure the system so that the update processing of the second calculation model is performed as needed based on the trigger signal T from the engine characteristic estimation unit 130 at any given time, without providing such a dedicated update mode.

[0064] Figure 6 shows the processing flow for engine characteristic estimation using the engine characteristic estimation device 100 having the above configuration. In step S10, the calculation model update mode execution unit 150 determines whether the update mode is being executed. If update mode is being executed, in step S21 the simulator 110 calculates the first engine state parameter X1, and in step S22, which is parallel to this, the observer 120 calculates the second engine state parameter X2.

[0065] In step S30, the engine characteristic estimation unit 130 calculates the differences e1, e2, ..., en (characteristic estimation output) of each element of the first engine state parameter X1 and the second engine state parameter X2. In step S40, it is determined whether the engine characteristic estimation unit 130 has generated a trigger signal T for the calculation model update unit 140 based on the characteristic estimation outputs e1, e2, ..., en. When a trigger signal T is generated, in step S50, the calculation model update unit 140 updates the second calculation model of the observer 120 based on the characteristic estimation outputs e1, e2, ..., en.

[0066] Figure 7 is a schematic diagram showing an example of engine characteristic estimation using the engine characteristic estimation device 100 described above. Similar to Figure 1, the engine 200, simulator 110, and observer 120 are shown as blocks that output the state parameters of the engine 200. Furthermore, the following explanation assumes an ideal state in which there are no disturbances affecting the engine 200, but this embodiment is also applicable in the case of disturbances.

[0067] Figure 7(A) shows the initial state of engine 200. Engine 200 is described by a system coefficient matrix A0 that represents its initial state characteristics and outputs state parameters X0 for an input of fuel supply amount U per combustion. The simulator 110 calculates a first engine state parameter from the input of the fuel supply amount U per combustion, based on a first calculation model that represents the characteristics of the engine 200 in its initial state. The simulator 110 accurately reproduces the engine 200 in its initial state, and its output, the first engine state parameter, matches the state parameter X0 of the engine 200 in the initial state described above.

[0068] Observer 120 calculates a second engine state parameter from the input fuel supply amount U per combustion and operating data X0', based on a second calculation model that includes the same system coefficient matrix A0 as the initial state of engine 200. Here, observer 120 estimates the initial state of engine 200 based on the system coefficient matrix A0, and assuming an estimation accuracy of 100%, the second engine state parameter will match the state parameter X0 of engine 200 in the initial state described above. Therefore, in the initial state shown in Figure 7(A), the outputs of the engine 200, simulator 110, and observer 120 are identical. The output of the difference calculation unit 131, which calculates the difference between the outputs of simulator 110 and observer 120, is zero.

[0069] Figure 7(B) shows the state in which the characteristics of engine 200 have changed due to deterioration over time from the initial state. The system coefficient matrix of engine 200 is assumed to have changed from its initial state A0 to A1 due to the deterioration of engine 200. Furthermore, the state parameter has also changed from its initial state X0 to X due to the change in the system coefficient matrix. The first calculation model of simulator 110 remains unchanged from its initial state. Furthermore, since the fuel supply amount U per combustion, which is the input to simulator 110, is a drive input amount unrelated to the deterioration of engine 200, the first engine state parameter, which is the output of simulator 110, remains unchanged from its initial state and is represented by X0.

[0070] The second calculation model of Observer 120 remains unchanged from its initial state and includes the system coefficient matrix A0 of the engine 200's initial state. On the other hand, the operation data X' input from engine 200 to Observer 120 is affected by the degradation of engine 200 and has changed from the input X0' to Observer 120 in its initial state. As a result, the second engine state parameter, which is the output of Observer 120, has changed to X2, which is different from the initial X0.

[0071] Thus, in the degradation state shown in Figure 7(B), a discrepancy occurs between the first engine state parameter X1 (equal to X0) and the second engine state parameter X2 (different from X0), and the output of the difference calculation unit 131 is no longer zero (X2-X0). In this way, the engine characteristic estimation device 100 of this embodiment can estimate the degradation of the engine 200, that is, the change in the system coefficient matrix from A0 to A1, based on this discrepancy.

[0072] Figure 7(C) shows the state after the calculation model update unit 140 has updated the observer 120, taking into account the degradation of engine 200 estimated in Figure 7(B). Based on the above-mentioned deviation data X2-X0 calculated in the degraded state, the calculation model update unit 140 estimates the system coefficient matrix A1 of engine 200 after degradation and updates the system coefficient matrix in the second calculation model of observer 120 from A0 to A1. As a result, the system coefficient matrix of observer 120 reflects the characteristics of engine 200 after degradation, and the estimation accuracy of engine 200 by observer 120 is improved. Here, assuming an estimation accuracy of 100%, the output of observer 120 perfectly matches the output X of engine 200.

[0073] As described above, the engine characteristic estimation device 100 of this embodiment can improve the accuracy of engine 200 state estimation by estimating the deterioration of the engine 200 and performing update processing of the observer 120 based on that estimate.

[0074] In the updated state shown in Figure 7(C), a steady-state discrepancy of X-X0 occurs between the output X of the observer 120 and the output X0 of the simulator 110, but this is not a problem. If the discrepancy remains at X-X0 after the update, it indicates that no further deterioration has occurred in the engine 200, so there is no need to perform further calculation model updates by the calculation model update unit 140, and the system can be operated normally in that state. On the other hand, if further deterioration occurs in the engine 200 and the discrepancy changes further from X-X0, the system coefficient matrix of the observer 120 can be updated by performing further calculation model updates by the calculation model update unit 140 to reflect the latest characteristics of the engine 200.

[0075] In Figure 7(A), the example given is that the outputs of simulator 110 and observer 120 match in the initial state, but they may differ. Here, if we let the initial output of simulator 110 be X0 and the initial output of observer 120 be X, the initial discrepancy can be expressed as X - X0. This is essentially the same as the situation in Figure 7(C) where a steady-state discrepancy X - X0 exists.

[0076] Furthermore, in order to seemingly eliminate the steady-state discrepancy described above, it is also possible to update the first calculation model of the simulator 110. That is, if a steady-state discrepancy X2-X1 exists between the first engine state parameter X1 of the simulator 110 and the second engine state parameter X2 of the observer 120 at a predetermined reference point, such as the initial point in Figure 7(A) or the update point in Figure 7(C), the output of the simulator 110 is corrected from X1 to X2 by updating the first calculation model of the simulator 110. As a result, the outputs of both the simulator 110 and the observer 120 become X2, thus seemingly eliminating the steady-state discrepancy described above.

[0077] Even when updating the first calculation model of the simulator 110 in this way, it is preferable to retain the first calculation model corresponding to the initial state. The initial state is an absolute standard state for estimating and controlling the characteristics of the engine 200, so it is good to keep it available for reference at all times. For example, when updating the first calculation model of the simulator 110 in the updated state shown in Figure 7(C), the first calculation model corresponding to the initial state can be retained as is, and a new first calculation model corresponding to the updated state can be added. In this case, the simulator 110 calculates the first engine state parameters corresponding to the initial state and the first engine state parameters corresponding to the updated state, respectively. Then, the difference calculation unit 131 calculates the difference between each first engine state parameter and the second engine state parameter, thereby estimating the degradation of the engine 200 from the initial state and from the updated state, respectively.

[0078] In addition to what has been described above, this embodiment provides the following effects and benefits, for example. The fuel supply amount U per combustion used in the simulator 110's calculations is data that is not affected by changes in the engine 200's characteristics due to aging or changes in the external environment such as intake air temperature. Therefore, the first engine state parameter X1, which is the result of this calculation, is not affected by changes in the engine 200's characteristics. In contrast, the engine 200's operating data used in the observer 120's calculations is data that is affected by changes in the engine 200's characteristics. Therefore, the second engine state parameter X2, which is the result of this calculation, is affected by changes in the engine 200's characteristics. By using the characteristic estimation output, which is the difference between these two types of engine state parameters X1 and X2 that are affected differently by changes in engine characteristics, the engine characteristic estimation unit 130 can estimate changes in the engine 200's characteristics (changes from A0 to A1 in the system coefficient matrix) with high accuracy. Even if there are no changes in the engine 200's characteristics, the state of the engine 200 can be estimated with high accuracy by using two calculation units with different calculation models in combination.

[0079] By using models that represent the initial characteristics of the engine 200 as the first calculation model for the simulator 110 and the second calculation model for the observer 120, the changes in the characteristics of the engine 200 from its initial state can be effectively estimated.

[0080] By providing a calculation model update unit 140 that updates the second calculation model of the observer 120 based on the characteristics of the engine 200 estimated by the engine characteristic estimation unit 130, the accuracy of the engine 200 state estimation by the observer 120 can be maintained at a high level even if the engine 200 deteriorates.

[0081] Some of the parameters that make up the first engine state parameter X1 and the second engine state parameter X2 exhibit nonlinearity, but in some cases, this nonlinearity can be reduced by calculating the difference between them. In this embodiment, the difference calculation unit 131 calculates the difference between the first engine state parameter X1 and the second engine state parameter X2, thereby converting them into an easy-to-handle form with reduced nonlinearity, and enabling the estimation of the characteristics of the engine 200.

[0082] The present invention has been described above based on embodiments. The embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications also fall within the scope of the present invention.

[0083] In this embodiment, the engine characteristic estimation unit 130 includes a difference calculation unit 131 that calculates the difference between a first engine state parameter X1 and a second engine state parameter X2, and estimates the characteristics of the engine 200 based on this difference. However, it is also possible to estimate the characteristics of the engine 200 based on other calculations. For example, since the input data and calculation models of the simulator 110 and the observer 120 are different, it is possible that the estimation accuracy cannot be maximized by using a simple difference between X1 and X2. In that case, the function that performs the characteristic estimation calculation in the engine characteristic estimation unit 130 can be optimized, taking into account the differences in the input data and calculation models of the two. If such a function is generalized and set as f(X1, X2), the engine characteristic estimation unit 130 can be considered as a calculation unit that takes X1 and X2 as inputs and outputs a characteristic estimation output f(X1, X2). In the example of difference calculation described in this embodiment, f(X1, X2) = X2 - X1.

[0084] In the embodiment described, an engine characteristic estimation device 100 was described, comprising a simulator 110 as a first calculation unit that calculates a first engine state parameter X1 using a first calculation model, an observer 120 as a second calculation unit that calculates a second engine state parameter X2 using a second calculation model, and an engine characteristic estimation unit 130 that estimates the characteristics of the engine 200 based on X1 and X2. However, it is also possible to configure an engine state estimation device that estimates the state of the engine 200 using only the simulator 110 and the observer 120 without providing the engine characteristic estimation unit 130. With this engine state estimation device, the state of the engine 200 can be estimated with high accuracy by using two calculation units with different calculation models in combination. For example, when estimating the scavenging pressure as a state parameter of the engine 200, since the estimated value is included in both the first engine state parameter X1 from the simulator 110 and the second engine state parameter X2 from the observer 120, the scavenging pressure can be estimated with high accuracy by calculating the average value of these two estimated values. In general, one can prepare a function g(X1, X2) optimized for estimating the state of engine 200, taking into account the differences in each calculation model, and configure an engine state estimation unit as a calculation unit that takes X1 and X2 as inputs and outputs a state estimation output g(X1, X2). In the example above where the average value is calculated, g(X1, X2) = (X1 + X2) / 2. Furthermore, the engine state estimation unit may be configured to perform calculations using g(X1, X2) not only on instantaneous data of X1 and X2, but also on historical data of X1 and X2 over a certain period in the past.

[0085] The functional configurations of each device described in the embodiments can be realized using hardware resources, software resources, or through the collaboration of hardware and software resources. Hardware resources can include processors, ROMs, RAMs, and other LSIs. Software resources can include operating systems, applications, and other programs.

[0086] In the embodiments disclosed herein, those in which multiple functions are provided in a distributed manner may have some or all of those multiple functions integrated into a single unit, and conversely, those in which multiple functions are integrated may have some or all of those functions distributed into a single unit. Whether the functions are integrated or distributed, the configuration should be such that the objective of the invention can be achieved. [Explanation of Symbols]

[0087] 100...Engine characteristic estimation device, 110...Simulator, 120...Observer, 130...Engine characteristic estimation unit, 131...Differential calculation unit, 140...Calculation model update unit, 150...Calculation model update mode execution unit, 200...Engine, 210...Engine body, 220...Intake passage, 230...Exhaust passage, 240...Supercharger, X1...First engine state parameter, X2...Second engine state parameter.

Claims

1. A first calculation unit calculates a first engine state parameter, which is a state variable of the engine at the reference time, based on a first calculation model representing the characteristics of the engine at a reference time and the amount of fuel supplied to the engine at an arbitrary time; A second calculation unit calculates, in parallel with the first calculation unit, second engine state parameters, which are real-time state variables of the engine, based on a second calculation model that represents the system characteristics of the engine and is different from the first calculation model, and operation data relating to the operation of the engine being driven at any given time, wherein the second engine state parameters have the same number of parameters as the first engine state parameters and each corresponds to the other. An engine characteristic estimation unit estimates the characteristics of the engine at any given time based on the first engine state parameter and the second engine state parameter. Equipped with, The aforementioned operation data is a part of the state parameters included in the first engine state parameter and the second engine state parameter, The engine characteristic estimation unit estimates at least one of the following as characteristics of the engine: combustion efficiency, power transmission efficiency, dynamic characteristics, the efficiency of the supercharger that increases the pressure of the air flowing into the engine body, and the influence of external disturbances on the engine. The engine characteristic estimation unit includes a difference calculation unit that calculates the difference between the first engine state parameter and the second engine state parameter, and estimates the characteristics of the engine based on the difference. An engine characteristic estimation device comprising a calculation model update unit that updates the second calculation model based on the aforementioned difference.

2. The first calculation model represents the characteristics of the engine in its initial state. The engine characteristic estimation device according to claim 1.

3. The second calculation model includes a system coefficient matrix representing the characteristics of the second calculation unit, The calculation model update unit updates at least one element in the system coefficient matrix. The engine characteristic estimation device according to claim 1.

4. The calculation model update unit updates the second calculation model when the difference exceeds a predetermined threshold. An engine characteristic estimation device according to any one of claims 1 to 3.

5. The calculation model update unit updates the second calculation model if the difference exceeds the threshold for a predetermined period of time. The engine characteristic estimation device according to claim 4.

6. The system includes a calculation model update mode execution unit that executes an update mode for updating the second calculation model by the calculation model update unit, The calculation model update unit updates the second calculation model based on the difference during the update mode. An engine characteristic estimation device according to any one of claims 1 to 5.

7. The engine characteristic estimation unit includes a difference calculation unit that calculates the difference between the first engine state parameter and the second engine state parameter, and estimates the characteristics of the engine based on the difference. An engine characteristic estimation device according to any one of claims 1 to 6.

8. The difference calculation unit comprises a plurality of differencers, The multiple differencers calculate the difference between the multiple parameters included in the first engine state parameter and the multiple parameters included in the corresponding second engine state parameter. The engine characteristic estimation device according to claim 7.

9. The aforementioned operation data includes engine body data relating to the operation of the engine body and supercharger data relating to the operation of the supercharger that increases the pressure of the air flowing into the engine body. An engine characteristic estimation device according to any one of claims 1 to 8.

10. The engine body data includes at least one of the engine body's rotational speed, exhaust temperature, exhaust pressure, and displacement. The engine characteristic estimation device according to claim 9.

11. The supercharger data includes at least one of the supercharger's rotational speed, intake air temperature, intake pressure, intake air volume, scavenging air temperature, scavenging pressure, and scavenging air volume. The engine characteristic estimation device according to claim 9 or 10.

12. The operation data includes mechanical data relating to the mechanical operation of the engine and thermodynamic data relating to the thermodynamic state of the engine. An engine characteristic estimation device according to any one of claims 1 to 11.

13. The aforementioned mechanical data includes at least one of the rotational speed of the engine body and the rotational speed of the supercharger that increases the pressure of the air flowing into the engine body. The engine characteristic estimation device according to claim 12.

14. The thermodynamic data includes at least one of exhaust gas temperature, exhaust pressure, exhaust volume, intake air temperature, intake air pressure, intake air volume, scavenging air temperature, scavenging air pressure, and scavenging air volume. The engine characteristic estimation device according to claim 12 or 13.

15. The second calculation unit calculates the second engine state parameter based on the fuel supply amount in addition to the operation data. An engine characteristic estimation device according to any one of claims 1 to 14.

16. The aforementioned engine is a marine engine with a rated rotational speed of 1,000 revolutions per minute or less. An engine characteristic estimation device according to any one of claims 1 to 15.

17. A first calculation step of calculating a first engine state parameter, which is a state variable of the engine at the reference time, based on a first calculation model representing the characteristics of the engine at a reference time and the amount of fuel supplied to the engine at an arbitrary time; A second calculation step, performed in parallel with the first calculation step, calculates second engine state parameters, which are real-time state variables of the engine, based on a second calculation model that represents the system characteristics of the engine and is different from the first calculation model, and operation data relating to the operation of the engine being driven at any given time, wherein the second engine state parameters have the same number of parameters as the first engine state parameters and each corresponds to the other. An engine characteristic estimation step of estimating the characteristics of the engine at any given time based on the first engine state parameter and the second engine state parameter. It has, The aforementioned operation data is a part of the state parameters included in the first engine state parameter and the second engine state parameter, The engine characteristic estimation step estimates at least one of the following as characteristics of the engine: combustion efficiency, power transmission efficiency, dynamic characteristics, the efficiency of the supercharger that increases the pressure of the air flowing into the engine body, and the influence of external disturbances on the engine. The engine characteristic estimation step includes a difference calculation step that calculates the difference between the first engine state parameter and the second engine state parameter, and estimates the characteristics of the engine based on the difference. An engine characteristic estimation method comprising a calculation model update step in which the second calculation model is updated based on the aforementioned difference.

18. A first calculation step of calculating a first engine state parameter, which is a state variable of the engine at the reference time, based on a first calculation model representing the characteristics of the engine at a reference time and the amount of fuel supplied to the engine at an arbitrary time; A second calculation step, performed in parallel with the first calculation step, calculates second engine state parameters, which are real-time state variables of the engine, based on a second calculation model that represents the system characteristics of the engine and is different from the first calculation model, and operation data relating to the operation of the engine being driven at any given time, wherein the second engine state parameters have the same number of parameters as the first engine state parameters and each corresponds to the other. An engine characteristic estimation step of estimating the characteristics of the engine at any given time based on the first engine state parameter and the second engine state parameter. Have the computer run it, The aforementioned operation data is a part of the state parameters included in the first engine state parameter and the second engine state parameter, The engine characteristic estimation step estimates at least one of the following as characteristics of the engine: combustion efficiency, power transmission efficiency, dynamic characteristics, the efficiency of the supercharger that increases the pressure of the air flowing into the engine body, and the influence of external disturbances on the engine. The engine characteristic estimation step includes a difference calculation step that calculates the difference between the first engine state parameter and the second engine state parameter, and estimates the characteristics of the engine based on the difference. An engine characteristic estimation program that causes the computer to perform a calculation model update step, which updates the second calculation model based on the aforementioned difference.

19. A first calculation unit calculates a first engine state parameter, which is a state variable of the engine at the reference time, based on a first calculation model representing the characteristics of the engine at a reference time and the amount of fuel supplied to the engine at an arbitrary time; A second calculation unit calculates, in parallel with the first calculation unit, second engine state parameters, which are real-time state variables of the engine, based on a second calculation model that represents the system characteristics of the engine and is different from the first calculation model, and operation data relating to the operation of the engine being driven at any given time, wherein the second engine state parameters have the same number of parameters as the first engine state parameters and each corresponds to the other. An engine state estimation unit estimates the state of the engine at any given time based on the first engine state parameter and the second engine state parameter. Equipped with, The aforementioned operation data is a part of the state parameters included in the first engine state parameter and the second engine state parameter, The engine state estimation unit estimates at least one of the following as the engine state: rotational speed, exhaust pressure, exhaust temperature, displacement, intake air temperature, intake air pressure, intake air volume, scavenging air temperature, scavenging air pressure, scavenging air volume, and rotational speed, intake air temperature, intake air pressure, intake air volume, scavenging air temperature, scavenging air pressure, and scavenging air volume of the supercharger which increases the pressure of the air flowing into the engine body. The engine state estimation unit includes a difference calculation unit that calculates the difference between the first engine state parameter and the second engine state parameter, and estimates the state of the engine based on the difference. An engine state estimation device comprising a calculation model update unit that updates the second calculation model based on the aforementioned difference.

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