In-cylinder residual fuel amount calculation system

Abstract

To provide an intra-cylinder residual fuel amount calculation system for calculating an intra-cylinder residual fuel amount for each cycle of an engine.SOLUTION: The present invention relates to a residual fuel amount calculation system W for the inside of a cylinder 1 of an engine E installed in an engine test device B. The residual fuel amount calculation system comprises: a high-response flowmeter 20 for measuring an intake amount for each cycle flowing into the engine E; a fuel flowmeter 26 for measuring a throw-in fuel amount for each cycle to be thrown into the engine E; a high-response THC concentration meter 24 for measuring a THC volume concentration of an exhaust gas for each cycle of the engine E; a first pressure gauge 21 for measuring an intra-cylinder pressure of the cylinder 1; a second pressure gauge 22 for measuring an exhaust pressure; a thermometer 23 for measuring an exhaust temperature; a rotary encoder 25 for measuring a crank angle; and an arithmetic unit 100 for calculating an intra-cylinder residual fuel amount of the engine. The arithmetic unit 100 calculates the intra-cylinder residual fuel amount of the cylinder 1 for each cycle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a system for calculating an amount of residual fuel in a cylinder, for example, a system for calculating the amount of residual fuel in a cylinder of an automobile engine. [Background technology]

[0002] Patent Document 1 discloses an in-cylinder fuel amount measurement system that measures the amount of fuel remaining in a cylinder of an engine. The in-cylinder fuel amount measurement system described in Patent Document 1 calculates the amount of fuel remaining in a cylinder in the following procedure. In this in-cylinder fuel amount measurement system, first, the engine is operated until a predetermined state is reached, and then fuel injection is stopped to put the engine into a motoring state. Next, in the motoring state, the in-cylinder fuel amount measurement system repeats the exhaust process, samples the gas in the cylinder in synchronization with each exhaust process, obtains the HC concentration from the extracted gas, and calculates the amount of fuel in the exhaust process from the HC concentration and the exhaust gas flow rate. In addition, the in-cylinder fuel amount measurement system determines whether the HC concentration is at the same level as the atmosphere in each exhaust process, and when the HC concentration becomes the same level as the atmosphere, stops the exhaust process, sums up the fuel amounts calculated in each exhaust process, and sets the sum to the amount of fuel remaining in the cylinder.

[0003] In addition, the invention described in Patent Document 1 focuses on the fact that the amount of white smoke has a high correlation with the amount of unburned fuel emitted, and calculates the amount of fuel remaining in the engine cylinders as an index showing the amount of white smoke. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-184441 Summary of the Invention [Problem to be solved by the invention]

[0005] However, automobile engines have a problem that even if the fuel injection amount is increased during acceleration, the engine output does not increase immediately due to a delay in the adhesion and evaporation of fuel inside the engine cylinder, and the desired acceleration cannot be realized. This problem also leads to a deterioration in fuel efficiency and exhaust gas properties. In the course of conducting research into the above-mentioned problems, the inventors of the present application came up with the idea that if it were possible to grasp the amount of residual fuel in the cylinder for each engine cycle (per cycle), it would be possible to predict and control the optimal fuel injection amount, taking into account the amount of residual fuel in the cylinder of the engine for each cycle. However, currently, there is no known device or system that can grasp the amount of fuel remaining in a cylinder for each engine cycle. The invention described in the above-mentioned Patent Document 1 calculates the amount of fuel remaining in an engine when the engine is stopped, but does not calculate the amount of fuel remaining in a cylinder for each engine cycle. In the first place, the invention described in Patent Document 1 calculates an index that indicates the amount of white smoke, and is not a technology based on the idea of ​​grasping the amount of fuel remaining in an engine cylinder for each cycle.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide an in-cylinder residual fuel amount calculation system that calculates the amount of fuel remaining in a cylinder for each cycle of an engine. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a system for calculating the amount of residual fuel in a cylinder of an engine installed in an engine testing device, the system including: a high-response flowmeter connected to an intake pipe of the engine and measuring the amount of intake air flowing into the engine for each cycle; a fuel flowmeter measuring the amount of injected fuel injected into the engine for each cycle; and a high-response THC concentration meter connected to an exhaust pipe of the engine and measuring the THC volume concentration of exhaust gas discharged into the exhaust pipe for each cycle. a first pressure gauge for measuring the pressure inside a cylinder of the engine; Exhaust gas a second pressure gauge for measuring the exhaust pressure of the exhaust pipe; Exhaust gas and a thermometer that measures an exhaust temperature of an engine, a rotary encoder that measures a crank angle of the engine, and a calculation device that calculates an amount of fuel remaining in a cylinder of the engine, wherein the calculation device acquires each measurement value measured by the high-response flow meter, the fuel flow meter, the high-response THC concentration meter, the first and second pressure gauges, the thermometer, and the rotary encoder while the engine testing device is operating the engine, and calculates the amount of fuel remaining in the cylinder for each cycle using the acquired measurement values.

[0008] In this way, the present invention is provided with a high-response THC volume concentration meter that measures the THC volume concentration for each cycle of the exhaust gas discharged from an engine installed in an engine test device. Also, the present invention is provided with a high-response flow meter that measures the intake amount flowing into the engine for each cycle, and a fuel flow meter that measures the amount of injected fuel for each cycle. With this configuration, the present invention can measure the "intake amount (intake air amount), injected fuel amount, and THC volume concentration (exhaust THC volume concentration)" for each cycle of the engine. Also, the present invention is configured such that the calculation device calculates the amount of fuel remaining in the cylinder for each cycle using the "intake amount (intake air amount), injected fuel amount, and THC volume concentration (exhaust THC volume concentration)" for each cycle obtained by measurement and the "measurement values ​​measured by each sensor (first pressure gauge, second pressure gauge, thermometer, rotary encoder)". Therefore, by using the present invention, for example, it is possible to perform optimal predictive control of the fuel injection amount while taking into consideration the amount of fuel remaining in the cylinder of the engine for each cycle. Furthermore, if the optimal fuel injection amount can be predicted and controlled, improvements in fuel economy and exhaust gas can be expected. Furthermore, if the optimal fuel injection amount can be predicted and controlled, it can be used for various engine analyses, for example, in engine performance tests performed on an engine bench.

[0009] It is also desirable that the amount of residual fuel in the cylinder for each cycle be calculated by calculating the amount of gas / residual fuel remaining in the cylinder in an evaporated state, the amount of evaporated fuel that evaporates from liquid fuel adhering to the cylinder during one cycle and emerges in the cylinder, and the amount of adhering / residual fuel that remains in the cylinder in a liquid state.

[0010] In this way, according to the present invention, it is possible to calculate, for each engine cycle, the "gas / residual fuel amount" that remains in the cylinder in an evaporated state, the "evaporated fuel amount" that evaporates from the liquid fuel attached to the inside of the cylinder during one cycle and emerges in the cylinder, and the "adhered / residual fuel amount" that remains in the cylinder in a liquid state. That is, in the present invention, by grasping the three factors that affect the combustion in the next cycle, namely, "gas and residual fuel amount," "evaporated fuel amount," and "adherent and residual fuel amount" per cycle, it becomes possible to predict and control the optimal fuel injection amount for the next cycle while taking these values ​​into consideration. And if the optimal fuel injection amount can be predicted and controlled, improvements in fuel economy and exhaust gas emissions can be expected.

[0011] The arithmetic unit also calculates a cylinder volume using pre-stored dimensional information of the engine and the crank angle measured by the rotary encoder, calculates a combustion / fuel amount per cycle using the calculated cylinder volume, a pre-stored lower heating value of the input fuel, and an in-cylinder pressure measured by the first pressure gauge, and calculates an intake amount measured by the high-response flowmeter and the Highly responsive THC concentration meter Using the THC volume concentration measured by Exhaust gas The amount of unburned fuel contained in the cylinder is calculated from the cylinder pressure and the crank angle. Exhaust valve closed and calculating the cylinder pressure at the time from the engine dimension information and the crank angle. Exhaust valve closed The cylinder volume at the time is calculated, Exhaust valve closed The cylinder pressure at Exhaust valve closedit is preferable to calculate the gas and residual fuel amount using the cylinder volume at the time of combustion, the exhaust temperature measured by the thermometer, and the exhaust pressure measured by the second pressure gauge, calculate the evaporated fuel amount by multiplying the value of the amount of adhered fuel accumulated in the cylinder, regressionally determined from the measured values, by an evaporation rate determined in a previously conducted experiment, calculate a total amount of fuel input to combustion in the cycle by adding the injected fuel amount for each cycle measured by the fuel flow meter, the calculated gas and residual fuel amount, and the calculated evaporated fuel amount, calculate a value obtained by subtracting the calculated burned fuel amount from the calculated total fuel amount as the unburned fuel amount per cycle, and calculate a value obtained by subtracting the emitted unburned fuel amount and the gas and residual fuel amount from the unburned fuel amount as the adhered and residual fuel amount.

[0012] Also, it is preferable that the arithmetic device calculates the combustion efficiency by dividing the calculated combustion / fuel amount per cycle by the calculated total amount of fuel input to combustion in the cycle.

[0013] Also, it is preferable that the calculation device calculates the emission rate per cycle by dividing the calculated amount of unburned fuel emitted per cycle by the calculated amount of unburned fuel emitted per cycle.

[0014] In this manner, the present invention makes it possible to calculate the combustion efficiency per cycle and the emission rate per cycle. Effect of the Invention

[0015] According to the present invention, it is possible to provide a system for calculating the amount of remaining fuel in a cylinder for each cycle of an engine. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing a configuration of an in-cylinder residual fuel amount calculation system according to an embodiment of the present invention; [Diagram 2]4 is a flowchart showing a procedure for calculating the amount of remaining fuel in a cylinder, which is performed by the system for calculating the amount of remaining fuel in a cylinder according to the embodiment of the present invention. [Diagram 3] 3 is a schematic diagram showing a relationship between a measurement value measured by the in-cylinder residual fuel amount calculation system according to the embodiment of the present invention and a calculation value calculated by the system. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a system for calculating an amount of residual fuel in a cylinder according to an embodiment of the present invention will be described with reference to the drawings. First, the configuration of the in-cylinder residual fuel amount calculation system of this embodiment will be described with reference to Fig. 1. Here, Fig. 1 is a schematic diagram showing the configuration of the in-cylinder residual fuel amount calculation system of this embodiment.

[0018] As shown in the figure, the in-cylinder residual fuel amount calculation system W of this embodiment includes a high-response flow meter 20 connected to the intake pipe 3 of an engine E installed in an engine testing device (engine bench) B and measuring the intake amount flowing into the engine E for each cycle, a pressure gauge (first pressure gauge) 21 measuring the in-cylinder pressure of a cylinder 1 of the engine E, a pressure gauge (second pressure gauge) 22 measuring the exhaust pressure of the exhaust gas exhausted by the engine E, a thermometer 23 measuring the exhaust temperature of the exhaust gas exhausted by the engine E, a high-response THC concentration meter 24 connected to the exhaust pipe 5 of the engine E and measuring the THC volume concentration of the exhaust gas exhausted into the exhaust pipe 5 for each cycle, a rotary encoder 25 measuring the crank angle of the engine, a fuel flow meter 26 measuring the amount of injected fuel (injection amount) input to the engine E for each cycle, and a calculation device 100 calculating the amount of residual fuel in the cylinder of the engine E.

[0019] In addition, reference numeral 7 in the drawing denotes a throttle valve, and reference numeral 11 denotes a fuel supply device that supplies fuel to a fuel injection device (injector) 9 of the engine E. Also, the above-mentioned fuel flow meter 26 is provided in a fuel supply pipe that connects the fuel supply device 11 and the fuel injection device 9.

[0020] In addition, engine bench B is equipped with a dynamometer 50 that applies a load to the engine E being tested, a shaft 52 that connects the rotating shaft of the dynamometer 50 to the rotating shaft of the engine E, a dynamo control device 51 that controls the operation of the dynamometer 50, and an engine control device 60 that controls the operation of the engine E. Since the engine bench B is a known technology, detailed description thereof will be omitted. Also, since the engine E to be tested is a known technology, only the parts directly related to the in-cylinder residual fuel amount calculation system W of this embodiment are shown in the figure.

[0021] The high response flowmeter 20 is connected to one end of the intake pipe 3 that sends air into the engine cylinder 1, and measures the intake amount (transient intake flow rate) of the fluid (air) for each cycle flowing into the engine E. The high response flowmeter 20 is also electrically connected to the calculation device 100, and upon measuring the intake amount, transmits the measured intake amount to the calculation device 100. The high-response flowmeter 20 refers to an air flowmeter that is more responsive (faster) to fluctuations in air flow rate than a "hot-wire airflow sensor" that is commonly installed in an automobile engine E. For example, a laminar flowmeter (laminar flow type flowmeter) or an ultrasonic flowmeter can be used as the high-response flowmeter 20. In this embodiment, the high-response flowmeter 20 is a laminar flowmeter.

[0022] The pressure gauge (first pressure gauge) 21 is installed inside the cylinder 1 and measures the in-cylinder pressure of the cylinder 1. The pressure gauge (first pressure gauge) 21 is also electrically connected to the arithmetic device 100, and transmits the measured in-cylinder pressure to the arithmetic device 100 upon measuring the in-cylinder pressure.

[0023] The pressure gauge (second pressure gauge) 22 is installed in the exhaust pipe 5, and measures the exhaust pressure of the exhaust gas discharged into the exhaust pipe 5. The pressure gauge 22 is also electrically connected to the arithmetic device 100, and transmits the measured exhaust pressure to the arithmetic device 100 upon measuring the exhaust pressure. Thermometer 23 is installed in exhaust pipe 5 and measures the exhaust temperature of the exhaust gas discharged into exhaust pipe 5. Thermometer 23 is also electrically connected to arithmetic device 100, and transmits the measured exhaust temperature to arithmetic device 100 upon measuring the exhaust temperature.

[0024] High-response THC concentration meter 24 is connected to exhaust pipe 5 via connection piping 13 which is connected to exhaust pipe 5, and measures the THC (total hydrocarbon) volume concentration (transient THC volume concentration) of exhaust gas for each cycle discharged into exhaust pipe 5. High-response THC concentration meter 24 is also electrically connected to calculation device 100, and upon measuring the THC volume concentration, transmits the measured THC volume concentration to calculation device 100. The high-response THC concentration meter 24 may be, for example, BHF-100F manufactured by Best Instruments Co., Ltd.

[0025] The arithmetic device 100 receives (acquires) the measurement values ​​(intake amount, in-cylinder pressure, exhaust pressure, exhaust temperature, THC volume concentration, crank angle, injected fuel amount) transmitted from each of the measurement devices (high-response flowmeter 20, pressure gauge (first pressure gauge) 21, pressure gauge (second pressure gauge) 22, thermometer 23, high-response THC concentration meter 24, rotary encoder 25, fuel flow meter 26). In addition, the arithmetic device 100 uses each of the acquired measurement values ​​to calculate the in-cylinder residual fuel amount (gas-residual fuel amount (M Res ), amount of evaporated fuel (M EV ), amount of adhering / residual fuel (M Liq ) is calculated.

[0026] In this embodiment, the calculation device 100 acquires measurement values ​​by wireless or wired communication between each measuring device (high-response flowmeter 20, pressure gauge (first pressure gauge) 21, pressure gauge (second pressure gauge) 22, thermometer 23, high-response THC concentration meter 24, rotary encoder 25, and fuel flow meter 26), but this is merely one example. The user may perform an input operation on the arithmetic device 100, so that the measurement values ​​measured by each measuring device (high-response flowmeter 20, pressure gauge (first pressure gauge) 21, pressure gauge (second pressure gauge) 22, thermometer 23, high-response THC concentration meter 24, rotary encoder 25, fuel flow meter 26) are input to the arithmetic device 100.

[0027] Next, a functional configuration of the arithmetic device 100 constituting the in-cylinder residual fuel amount calculation system W of this embodiment will be described.

[0028] As shown in FIG. 1, the calculation device 100 includes a control unit 110, a data acquisition unit 120, and a remaining fuel amount calculation unit .

[0029] Although the hardware configuration of the arithmetic device 100 is not particularly limited, the arithmetic device 100 can be configured by, for example, a computer (one or more computers) including a CPU, an auxiliary storage device (storage unit), a main storage device (storage unit), a network interface, and an input / output interface. In this case, the input / output interface is connected to the "high-response flowmeter 20, pressure gauge (first pressure gauge) 21, pressure gauge (second pressure gauge) 22, thermometer 23, high-response THC concentration meter 24, rotary encoder 25, and fuel flowmeter 26." In addition, the auxiliary storage device stores programs for realizing the functions of the "control unit 110, data acquisition unit 120, and residual fuel amount calculation unit 130."

[0030] The functions of the "control unit 110, data acquisition unit 120, and residual fuel amount calculation unit 130" are realized by the CPU loading the programs into the main storage device and executing them. In addition, in a memory unit (auxiliary memory device or main memory device) of the calculation device 100, prior to the in-cylinder residual fuel amount calculation process, known data (data such as dimensional information of engine E, specific heat ratio, low heating value of fuel input to engine E, molecular weight of exhaust gas (exhaust molecular weight), average number of C atoms in fuel, etc.) to be used in the in-cylinder residual fuel amount calculation process is registered (stored) in advance. In addition, the “dimension information of engine E” is a value determined by the specifications of engine E installed on engine bench B, and the “specific heat ratio, low heating value, molecular weight of exhaust gas (exhaust molecular weight), and average number of C atoms in fuel” are values ​​determined by the fuel supplied to engine E.

[0031] The control unit 110 controls the overall operation of the arithmetic device 100, and receives various settings from a user and inputs of known data (such as dimensional information of the engine E, the specific heat ratio, the lower heating value of the fuel fed to the engine E, the molecular weight of the exhaust gas (exhaust molecular weight), the average number of atoms in the fuel, and other information). The control unit 110 also receives an operation request from a user to the in-cylinder residual fuel amount calculation system W.

[0032] The data acquisition unit 120 acquires the measurement values ​​(intake volume, in-cylinder pressure, exhaust pressure, exhaust temperature, THC volume concentration, crank angle, injected fuel amount) measured by each measuring device (high-response flow meter 20, pressure gauge (first pressure gauge) 21, pressure gauge (second pressure gauge) 22, thermometer 23, high-response THC concentration meter 24, rotary encoder 25, fuel flow meter 26) at a specified measurement timing.

[0033] The residual fuel amount calculation unit 130 calculates the amount of residual fuel in the cylinder 1 per cycle (gas residual fuel amount (M Res ), amount of evaporated fuel (M EV ), amount of adhering / residual fuel (M Liq In addition, the residual fuel amount calculation unit 130 calculates the "combustion efficiency (η), unburned rate (1-η), emission rate (G), and deposition rate (1-G)" per cycle of the engine E using the calculated values.

[0034] Next, a procedure for calculating the amount of remaining fuel in a cylinder performed by the system W for calculating the amount of remaining fuel in a cylinder according to this embodiment will be described. FIG. 2 is a flowchart showing a procedure for calculating the amount of remaining fuel in a cylinder, which is performed by the system for calculating the amount of remaining fuel in a cylinder according to this embodiment.

[0035] Prior to the calculation process of the in-cylinder residual fuel amount performed by the in-cylinder residual fuel calculation system W, known data (dimensional information of the engine E, specific heat ratio (γ), low-temperature heating value (Q LHV ), the average molar mass of the fuel (W Fuel ), the average number of C atoms in the fuel (Nc), and the mass per mole of exhaust gas (W Exh ) and other data).

[0036] As shown in the figure, the in-cylinder residual fuel amount calculation system W first performs a data measurement process (S1).

[0037] In this data measurement process (S1), first, the engine bench B is driven, and the engine E installed on the engine bench B is operated. In addition, the in-cylinder residual fuel amount calculation system W calculates the intake amount (M Air ), the pressure gauge 21 measures the cylinder pressure (P), and the pressure gauge 22 measures the exhaust pressure (P Exh ) and the exhaust temperature (T EXh The in-cylinder residual fuel amount calculation system W also measures the THC volume concentration (C THC ), the rotary encoder 25 measures the crank angle, and the fuel flow meter 26 measures the amount of fuel injected per cycle (M Inj ) is measured.

[0038] In the data measurement process (S1), the data acquisition unit 120 of the calculation device 100 acquires the “intake volume (M Air), the cylinder pressure (P) measured by the pressure gauge 21, and the exhaust pressure (P) measured by the pressure gauge 22. Exh ), the exhaust temperature (T EXh ), and the THC volume concentration per cycle measured by the high-response THC concentration meter 24 (C THC ), the crank angle measured by the rotary encoder 25, the amount of fuel injected per cycle measured by the fuel flow meter 26 (M Inj )" The data acquisition unit 112 acquires the measurement value (intake volume per cycle (M Air ), cylinder pressure (P), exhaust pressure (P Exh ), exhaust temperature (T EXh ), THC volume concentration per cycle (C THC ), crank angle, fuel injection amount per cycle (M Inj ) are stored in association with each other (for example, in a storage unit (auxiliary storage device and main storage device of the arithmetic device 100) not shown).

[0039] Next, the in-cylinder residual fuel amount calculation system W calculates the combustion and fuel amount per cycle (M Burnt ) is calculated (S2). In this step (S2), first, the residual fuel amount calculation unit 130 of the arithmetic unit 100 receives the measurement values ​​(intake amount per cycle (M Air ), cylinder pressure (P), exhaust pressure (P Exh ), exhaust temperature (T EXh ), THC volume concentration per cycle (C THC ), crank angle, fuel injection amount per cycle (M Inj )) to get the In S2, the residual fuel amount calculation unit 130 calculates the residual fuel amount based on known data (dimension information of the engine E, specific heat ratio (γ), and lower heat value (Q LHV ), the average molar mass of the fuel (W Fuel ), the average number of C atoms in the fuel (Nc), and the mass per mole of exhaust gas (W Exh ) and other data.

[0040] In step S2, the residual fuel amount calculation unit 130 calculates the residual fuel amount by calculating the cylinder pressure (P) and crank angle obtained from the data measurement unit 120 and the engine E dimension information, specific heat ratio (γ), and low-temperature heat generation amount (Q LHV ) and the following (Equation 1) to calculate the "combustion and fuel amount per cycle (M Burnt )" and proceed to processing in S3.

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[0041] Specifically, in S2, the residual fuel amount calculation unit 130 calculates the "cylinder volume (V)" using the read "engine E dimension information" and the acquired "crank angle". In addition, the residual fuel amount calculation unit 130 calculates the "polytropic index ( k )" is calculated. The residual fuel amount calculation unit 130 calculates the residual fuel amount by calculating the above-mentioned "in-cylinder pressure (P)", the above-mentioned "cylinder volume (V)", and the above-mentioned "polytropic index ( k ) and the above "specific heat ratio (γ)" and the above "lower heating value (Q LHV ) and the above (Equation 1), the "combustion and fuel amount per cycle (M Burnt )" is calculated. In this embodiment, the "specific heat ratio (γ)" is approximately 1.4.

[0042] Next, the residual fuel amount calculation unit 130 calculates the amount of unburned fuel discharged per cycle (M Exh ) is calculated (S3). Specifically, the residual fuel amount calculation unit 130 calculates the "intake amount per cycle (M Air ) and the "Mass per mole of exhaust gas (W Exh ) and the "THC volume concentration per cycle (C THC )" and the "average fuel mass per mole (W Fuel)” and the “average number of C atoms in the fuel (N c ) and the following (Equation 2) to calculate the amount of unburned fuel emitted per cycle (M Exh )" is calculated.

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[0043] Next, the residual fuel amount calculation unit 130 calculates the amount of gas and residual fuel (M Res ) is calculated (S4). Specifically, the residual fuel amount calculation unit 130 calculates the "cylinder pressure at the exhaust closing time (P EVC ) is calculated (obtained). In addition, the residual fuel amount calculation unit 130 calculates the "cylinder volume at the exhaust closing time (V EVC ) is calculated (obtained). The residual fuel amount calculation unit 130 calculates the above-mentioned "cylinder pressure at the exhaust closing time (P EVC ) and the above "Cylinder volume at exhaust closing time (V EVC ) and the "exhaust pressure (P EXh ), exhaust temperature (T EXh ), THC volume concentration (C THC ) and the specific heat ratio (γ), average fuel mass per mole (W Fuel ), the average number of C atoms in the fuel (N c ) and the amount of gas and residual fuel remaining in the evaporated state in cylinder 1 (M Res ) is calculated. In addition, R in (Equation 3) is the gas constant.

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[0044] Next, the residual fuel amount calculation unit 130 calculates the amount of evaporated fuel (M EV ) is calculated (S5). This amount of evaporated fuel (M EV ) refers to the amount of gaseous fuel that evaporates from the liquid fuel adhering to the cylinder during one cycle and emerges into cylinder 1. Specifically, the residual fuel amount calculation unit 130 calculates the amount of adhered fuel accumulated in the cylinder (M SLiq ) is multiplied by the evaporation rate E of the adhering fuel to obtain the amount of evaporated fuel (M EV ) is calculated. In addition, the amount of fuel that accumulates in the cylinder (M SLiq ) can be found by experimentally identifying the evaporation rate E (the evaporation rate E is identified by referring to the measurement results of the transient changes in THC concentration when combustion starts and stops). Specifically, increasing or decreasing the parameter "evaporation rate E" changes the calculation results of the deposition amount and evaporation amount. By adjusting the parameter "evaporation rate E" so that these and the various transient measurement values ​​when combustion starts and stops are consistent, the amount of evaporated fuel (M EV ) and the amount of fuel that has accumulated in the cylinder (M SLiq ) is determined (the amount of fuel adhering to the cylinder (M SLiq ) is a regression calculated value from the measured values.

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[0045] In addition, in S5, the residual fuel amount calculation unit 130 calculates the total amount of fuel (M Fuel ) is calculated. Specifically, the residual fuel amount calculation unit 130 calculates the “injection fuel amount per cycle measured by the fuel flow meter 26 (M Inj ) and "Gas and residual fuel amount calculated in S4 (M Res ) and the amount of evaporated fuel calculated using the above formula (4) (M EV )" to get the total fuel amount (M Fuel ) is calculated.

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[0046] Next, the residual fuel amount calculation unit 130 calculates the "unburned fuel amount per cycle (M unburnt ) is calculated (S6). Specifically, the residual fuel amount calculation unit 130 calculates the "total amount of fuel input to the combustion in that cycle (M Fuel )" calculated in S2, and "Combustion and fuel amount per cycle (M Burnt )” to obtain the “unburned fuel amount per cycle (M unburnt )" is calculated.

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[0047] Next, the residual fuel amount calculation unit 130 calculates the "adhered and residual fuel amount per cycle (M Liq ) is calculated (S7). In this step (S7), the residual fuel amount calculation section 130 calculates the "unburned fuel amount per cycle (M unburnt )" calculated in S3, and "unburned fuel amount per cycle (M Exh ) and the "gas and residual fuel amount per cycle (M Res )" to obtain the "amount of adhering and remaining fuel per cycle (M Liq )" is calculated.

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[0048] In this manner, the in-cylinder residual fuel amount calculation system W of this embodiment is provided with a high-response flowmeter 20 connected to the intake pipe 3 of the engine E installed on the engine bench B, a high-response THC concentration meter 24 connected to the exhaust pipe 5 of the engine E, and a fuel flowmeter 26 for measuring the amount of fuel input to the engine E. With this configuration, in this embodiment, the "intake amount (M Air ), injected fuel amount (M Inj ), THC volume concentration (CTHC ))" can be measured.

[0049] The present invention is directed to the "intake amount (M Air ), injected fuel amount (M Inj ), THC volume concentration (C THC Once the "measurement values ​​(in-cylinder pressure (P), exhaust pressure (P))" are grasped, the "measurement values ​​(in-cylinder pressure (P), exhaust pressure (P))" measured by each sensor (pressure gauge 21, pressure gauge 22, thermometer 23, rotary encoder 25) can be calculated. Exh ), exhaust temperature (T Exh ), crank angle) and known data determined by the dimensions of engine E and the type of fuel input (engine E's dimension information, specific heat ratio (γ), low-temperature heating value of the fuel input to engine E (Q LHV ), the average molar mass of the fuel (W Fuel ), the average number of C atoms in the fuel (N c ), mass per mole of exhaust gas (W Exh The inventors of the present application have come up with the idea that it is possible to calculate the in-cylinder residual fuel amount for each cycle by performing a calculation process using data such as the above data S2 to S7. Therefore, the inventors of the present application have provided the in-cylinder residual fuel amount calculation system W of this embodiment with a calculation device 100 having a residual fuel amount calculation unit 130 that performs the processes of the above "S2 to S7".

[0050] In this embodiment, the amount of gas and residual fuel remaining in the evaporated state in the cylinder 1 (M Res ) and "the amount of evaporated fuel (M EV ) and the amount of fuel remaining in liquid form in cylinder 1 (M Liq That is, in this embodiment, the amount of adhering / residual fuel remaining in the cylinder 1 of the engine E in a liquid state (M Liq ) and the amount of gas and residual fuel remaining in the cylinder 1 in an evaporated state (M Res ) and the amount of evaporated fuel that evaporates from the liquid fuel adhering to the cylinder during one cycle and comes out into the cylinder (M EV)" can be grasped, it is possible to predict and control the optimum fuel injection amount for the next cycle by taking into account these values ​​that affect the combustion in the next cycle. And if it is possible to predict and control the optimum fuel injection amount, it is expected that fuel economy and exhaust gas emissions will improve. Especially during cold start operation, it is necessary to know the "amount of adhering / residual fuel (M Liq ) is large and the deterioration of exhaust gas properties is significant, so predictive control of the optimal fuel injection amount using this embodiment is effective. Furthermore, if predictive control of the optimal fuel injection amount can be achieved, it can be used for various analyses of engine E in engine performance tests performed on engine bench B, for example.

[0051] In addition, the in-cylinder residual fuel amount calculation system W of this embodiment is configured to be able to calculate the “combustion efficiency (η), unburned fuel rate (1-η), emission rate (G), and deposition rate (1-G)” of the engine E using the calculated values ​​obtained by the flowchart shown in FIG. 2.

[0052] Hereinafter, the process of calculating the "combustion efficiency (η), unburned fuel ratio (1-η), emission ratio (G), and deposition ratio (1-G)" of the engine E will be described with reference to FIG. FIG. 3 is a schematic diagram showing the relationship between the measurement value measured by the in-cylinder residual fuel amount calculation system of this embodiment and the calculation value calculated by the system.

[0053] Specifically, the residual fuel calculation unit 130 of the arithmetic device 100 constituting the in-cylinder residual fuel amount calculation system W of this embodiment calculates the “combustion and fuel amount per cycle (M Burnt )" is calculated in S5 of Figure 2 as the "total fuel amount input to the combustion of the corresponding cycle (M Fuel ) to calculate the combustion efficiency (η). Specifically, the remaining fuel calculation unit 130 calculates the combustion efficiency (η) per cycle using the following (Equation 8).

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[0054] In addition, the residual fuel calculation unit 130 of the arithmetic device 100 constituting the in-cylinder residual fuel amount calculation system W of this embodiment calculates the "emission unburned fuel amount per cycle (M Exh )" is calculated in S6 as the "unburned fuel amount (M Burnt ) to calculate the emission rate per cycle (G). Specifically, the remaining fuel calculation unit 130 calculates the emission rate (G) per cycle using the following (Equation 8).

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[0055] In this manner, in this embodiment, the amount of gaseous fuel that evaporates from the liquid fuel adhering to the cylinder during one cycle and comes out into the cylinder 1 is referred to as the "evaporated fuel amount (M EV )” reflecting the total fuel amount (M Fuel ) is used to calculate the "combustion efficiency (η)", which allows the "combustion efficiency (η)" per cycle to be calculated with high accuracy. In this embodiment, the amount of evaporated fuel (M EV ) reflecting the "Total Fuel Quantity (M Fuel ) was used to calculate the "unburned fuel amount (M unburnt ) is used to calculate the "emission rate (G)", which allows the "emission rate (G)" per cycle to be calculated with high accuracy.

[0056] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention. [Explanation of symbols]

[0057] W…In-cylinder residual fuel amount calculation system 13...Connecting piping 20...High-response flowmeter 21...Pressure gauge (first pressure gauge) 22...Pressure gauge (second pressure gauge) 23…Thermometer 24…High-response THC concentration meter 25...Rotary encoder 26…Fuel flow meter 100...Arithmetic device 110...Control unit 120…Data acquisition section 130...Residual fuel amount calculation section E…Engine 1...Cylinder 3...Intake pipe 5…Exhaust pipe 7...Throttle valve 9...Fuel injection system (injector) 11…Fuel supply device B…Engine test equipment (engine bench) 50…Dynamometer 51...Dynamo control device 52…Shaft 60...Engine control device

Claims

1. A system for calculating an amount of residual fuel in a cylinder of an engine installed in an engine testing device, comprising: a high-response flowmeter connected to an intake pipe of the engine for measuring an intake amount flowing into the engine for each cycle; A fuel flow meter that measures the amount of fuel injected into the engine for each cycle; a high-response THC concentration meter connected to an exhaust pipe of the engine and configured to measure a THC volume concentration of exhaust gas discharged into the exhaust pipe for each cycle; A first pressure gauge that measures an internal pressure of a cylinder of the engine; a second pressure gauge installed in an exhaust pipe of the engine and configured to measure an exhaust pressure of the exhaust gas; a thermometer installed in the exhaust pipe for measuring an exhaust temperature of the exhaust gas; a rotary encoder for measuring a crank angle of the engine; A calculation device for calculating an amount of fuel remaining in a cylinder of the engine, The calculation device is configured to acquire each measurement value measured by the high-response flow meter, the fuel flow meter, the high-response THC concentration meter, the first and second pressure gauges, the thermometer, and the rotary encoder while the engine testing equipment is operating the engine, and to calculate the amount of remaining fuel in the cylinder for each cycle using the acquired measurement values.

2. The in-cylinder residual fuel amount calculation system according to claim 1, characterized in that the calculation device is configured to calculate, as the in-cylinder residual fuel amount for each cycle, the amount of gas / residual fuel remaining in the cylinder in an evaporated state, the amount of evaporated fuel that evaporates from the liquid fuel attached to the cylinder during one cycle and emerges in the cylinder, and the amount of attached / residual fuel that remains in the cylinder in a liquid state.

3. The computing device includes: calculating a cylinder volume using pre-stored dimensional information of the engine and the crank angle measured by the rotary encoder, and calculating a combustion / fuel amount per cycle using the calculated cylinder volume, a pre-stored lower heating value of the input fuel, and an in-cylinder pressure measured by the first pressure gauge; Calculating the amount of unburned fuel and unburned fuel contained in the exhaust gas using the intake air volume measured by the high-response flow meter and the THC volume concentration measured by the high-response THC concentration meter; calculating an in-cylinder pressure at the time when the exhaust valve is closed from the in-cylinder pressure and the crank angle, calculating a cylinder volume at the time when the exhaust valve is closed from the engine dimension information and the crank angle, and calculating the gas and residual fuel amount using the in-cylinder pressure at the time when the exhaust valve is closed and the cylinder volume at the time when the exhaust valve is closed, the exhaust temperature measured by the thermometer, and the exhaust pressure measured by the second pressure gauge; calculating the amount of evaporated fuel by multiplying a value of the amount of adhered fuel accumulated in the cylinder, the value being calculated by regression from the measured value, by an evaporation rate calculated in advance by an experiment; calculating a total amount of fuel input to combustion in the cycle by adding together the amount of fuel injected for each cycle measured by the fuel flow meter, the calculated amount of gas and residual fuel, and the calculated amount of evaporated fuel; Calculating a value obtained by subtracting the calculated burned fuel amount from the calculated total fuel amount as an unburned fuel amount per cycle; 3. The system for calculating the in-cylinder residual fuel amount according to claim 2, wherein the amount of adhering residual fuel is calculated by subtracting the amount of exhausted unburned fuel and the amount of gas and residual fuel from the amount of unburned fuel.

4. 4. The in-cylinder residual fuel amount calculation system according to claim 3, wherein the calculation device calculates the combustion efficiency by dividing the calculated combustion / fuel amount per cycle by the calculated total fuel amount input to the combustion in the cycle.

5. 4. The in-cylinder residual fuel amount calculation system according to claim 3, wherein the calculation device calculates the emission rate per cycle by dividing the calculated amount of unburned fuel and unburned fuel emitted per cycle by the calculated amount of unburned fuel and unburned fuel emitted per cycle.

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