JP5776704B2 - Fuel property determination device and fuel property determination method - Google Patents

Description

  The present invention relates to a fuel property determination device and a fuel property determination method for determining the property of fuel supplied to a fuel injection system.

  Conventionally, when the temperature of the fuel flowing inside the fuel supply pump rises by a predetermined level or more, there is one that determines that the fuel supply pump is abnormal (for example, see Patent Document 1). In the thing of patent document 1, since the temperature of the fuel which is lubricating oil will rise if abnormality, such as a sliding failure, arises inside a fuel supply pump by use of poor fuel, a pump will be based on the temperature of the fuel. Anomalies can be detected.

JP 2006-194224 A

  However, since the temperature change of the fuel is gradual, there is a possibility of adversely affecting the driving of the pump, fuel injection by the fuel injection valve, etc. before detecting the abnormality of the fuel supply pump. Further, in order to accurately detect the temperature of the fuel, a highly accurate temperature sensor is required.

  The present invention has been made in view of such circumstances, and its main object is to provide a fuel property determination device and a fuel property determination method that can quickly determine the fuel property without the need for an additional temperature sensor. It is to provide.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

According to a first aspect of the present invention, there is provided a pressure accumulating container for accumulating and holding fuel, a fuel injection valve for injecting the fuel from an injection hole, a fuel passage for allowing the fuel to flow from the pressure accumulating container to the injection hole, A fuel property determination device applied to a fuel injection system comprising a fuel pressure sensor for detecting fuel pressure, based on the fuel pressure detected by the fuel pressure sensor when the fuel is injected by the fuel injection valve, A waveform acquisition unit that acquires a pressure waveform indicating a change in the fuel pressure, and a pressure wave that forms the pressure waveform based on the pulsation cycle of the pressure waveform acquired by the waveform acquisition unit and the length of the fuel passage Calculated by the speed calculator, the density calculator for calculating the density of the fuel, and the density calculator based on the speed calculated by the speed calculator. A kinematic viscosity calculating unit that calculates the kinematic viscosity of the fuel based on the density; and a determination unit that determines the property of the fuel based on the kinematic viscosity calculated by the kinematic viscosity calculating unit. It is characterized by.

  According to the above configuration, the fuel is accumulated and held in the accumulator, and the fuel is circulated from the accumulator to the injection hole of the fuel injection valve through the fuel passage. The fuel pressure in the fuel passage is detected by a fuel pressure sensor.

  Here, a pressure waveform indicating a change in the fuel pressure is acquired based on the fuel pressure detected by the fuel pressure sensor when the fuel is injected by the fuel injection valve. Based on the pulsation cycle of the acquired pressure waveform and the length of the fuel passage, the velocity of the pressure wave forming the pressure waveform is calculated. That is, the pressure wave remaining in the fuel passage after fuel injection reciprocates in the fuel passage to form a stationary wave. For this reason, the velocity of the pressure wave can be calculated based on the pulsation cycle of the pressure waveform (oscillation cycle of the stationary wave) and the length of the fuel passage. In the standing wave, the position where the fuel pressure sensor detects the fuel pressure in the fuel passage is arbitrary.

  Then, the density of the fuel is calculated based on the calculated velocity of the pressure wave. That is, the fuel density can be calculated based on the physical relationship between the pressure wave velocity and the fuel density. Further, the kinematic viscosity of the fuel is calculated based on the calculated fuel density. That is, it is considered that there is a correlation between the density of the fuel and the kinematic viscosity of the fuel, and this correlation can be obtained in advance by experiments or the like. Therefore, the kinematic viscosity of the fuel can be calculated from the density of the fuel using this correlation.

  Since the kinematic viscosity of the fuel indicates characteristics of the fuel as a lubricating oil, the quality of the fuel property can be determined based on the kinematic viscosity of the fuel. In this way, the fuel property can be determined by detecting the fuel pressure with the fuel pressure sensor during fuel injection. Therefore, it is possible to quickly determine the fuel property without adding a temperature sensor.

According to a second aspect of the present invention, there is provided a pressure accumulating container for accumulating and holding fuel, a fuel injection valve for injecting the fuel from an injection hole, a fuel passage for allowing the fuel to flow from the pressure accumulating container to the injection hole, A fuel property determination device applied to a fuel injection system comprising a fuel pressure sensor for detecting fuel pressure, based on the fuel pressure detected by the fuel pressure sensor when the fuel is injected by the fuel injection valve, A waveform acquisition unit that acquires a pressure waveform indicating a change in the fuel pressure, and a pressure wave that forms the pressure waveform based on the pulsation cycle of the pressure waveform acquired by the waveform acquisition unit and the length of the fuel passage Calculated by the speed calculator, the density calculator for calculating the density of the fuel, and the density calculator based on the speed calculated by the speed calculator. Based on the density, characterized in that it and a determination unit that determines the properties of the fuel.

As described above, it is considered that there is a correlation between the density of the fuel and the kinematic viscosity of the fuel. Therefore, as in the second aspect , the property of the fuel can be determined based on the calculated density.

According to a third aspect of the present invention, there is provided a pressure accumulation container for accumulating and holding fuel, a fuel injection valve for injecting the fuel from an injection hole, a fuel passage for allowing the fuel to flow from the pressure accumulation container to the injection hole, A fuel injection system comprising: a fuel pressure sensor for detecting a fuel pressure; and a method for determining a property of the fuel, based on the fuel pressure detected by the fuel pressure sensor when the fuel is injected by the fuel injection valve. Obtaining a pressure waveform indicating a change in the fuel pressure, and calculating a velocity of the pressure wave forming the pressure waveform based on the pulsation period of the obtained pressure waveform and the length of the fuel passage. Calculating the density of the fuel based on the calculated speed, calculating the kinematic viscosity of the fuel based on the calculated density, and the calculated kinematic viscosity Based on, characterized in that it comprises a step of determining the properties of the fuel.

According to the said process, there can exist an effect similar to 1st invention.

The schematic diagram which shows the outline of a fuel-injection system. The time chart which shows the change of the injection rate and fuel pressure corresponding to an injection command signal. The flowchart which shows the process sequence of fuel property determination.

  Hereinafter, an embodiment applied to a common rail fuel injection system of an in-vehicle diesel engine will be described with reference to the drawings. The diesel engine (internal combustion engine) includes four cylinders # 1 to # 4, and injects high-pressure fuel into the cylinders to perform compression self-ignition combustion.

  FIG. 1 is a schematic diagram showing an outline of a fuel injection system. First, an engine fuel injection system including the fuel injection valve 10 will be described.

  The fuel in the fuel tank 40 is pumped by the fuel pump 41 to the common rail 42 (pressure accumulating container) and is accumulated and held. The common rail 42 is connected to the fuel injection valves 10 (# 1 to # 4) of the respective cylinders via the fuel pipes 42b. The fuel in the common rail 42 is distributed and supplied to the fuel injection valves 10 (# 1 to # 4) through the fuel pipes 42b. The plurality of fuel injection valves 10 (# 1 to # 4) inject fuel in a predetermined order. In this embodiment, it is assumed that repeated injection is performed in the order of # 1 → # 3 → # 4 → # 2.

  A plunger pump is used as the fuel pump 41, and fuel is pumped in synchronism with the reciprocating movement of the plunger. The fuel pump 41 is driven by the crankshaft using the engine output as a drive source, and pumps the fuel by a predetermined number of times during a period of injection in the order of # 1 → # 3 → # 4 → # 2.

  The fuel injection valve 10 includes a body 11, a needle-shaped valve body 12, an electric actuator 13, and the like described below. The body 11 has a high pressure passage 11a formed therein and an injection hole 11b for injecting fuel. The valve body 12 is accommodated in the body 11 and opens and closes the injection hole 11b. The fuel pipe 42b and the high pressure passage 11a constitute a fuel passage through which fuel flows from the common rail 42 to the injection hole 11b.

  A back pressure chamber 11c for applying a back pressure to the valve body 12 is formed in the body 11, and the high pressure passage 11a and the low pressure passage 11d are connected to the back pressure chamber 11c. The electric actuator 13 operates the control valve 14 so as to switch the communication state between the high pressure passage 11a and the low pressure passage 11d and the back pressure chamber 11c. The driving of the electric actuator 13 is controlled by the ECU 30.

  When the control valve 14 is operated so that the back pressure chamber 11c communicates with the low pressure passage 11d, the fuel pressure in the back pressure chamber 11c decreases, the valve body 12 is lifted up (opening operation), and the injection hole 11b is opened. It is. As a result, the high-pressure fuel supplied from the common rail 42 to the high-pressure passage 11a is injected from the injection hole 11b into the combustion chamber. On the other hand, when the control valve 14 is operated so that the back pressure chamber 11c communicates with the high pressure passage 11a, the fuel pressure in the back pressure chamber 11c rises and the valve body 12 is lifted down (closed valve operation), and the injection hole 11b. Is closed and fuel injection is stopped.

  The fuel pressure sensor 20 includes a stem 21 (a strain generating body), a pressure sensor element 22 and the like described below. The stem 21 is attached to the body 11, and the diaphragm portion 21a formed on the stem 21 is elastically deformed by receiving the pressure of the high-pressure fuel flowing through the high-pressure passage 11a. The pressure sensor element 22 is attached to the diaphragm portion 21a, and outputs a pressure detection signal to the ECU 30 in accordance with the amount of elastic deformation generated in the diaphragm portion 21a.

  The fuel pressure sensor 20 is mounted on all the fuel injection valves 10. In the following description, the fuel injection valve 10 mounted in the cylinder # 1 is described as the injection valve 10 (# 1), and the fuel pressure sensor 20 mounted in the injection valve 10 (# 1) is described as the sensor 20 (# 1). To do. Similarly, the fuel injection valve 10 and the fuel pressure sensor 20 mounted on the cylinders # 2 to # 4 are referred to as an injection valve 10 (# 2 to # 4) and a sensor 20 (# 2 to # 4).

  The ECU 30 (electronic control device) is a known microcomputer including a CPU, ROM, RAM, storage device, input / output interface, and the like. The ECU 30 calculates a target injection state (the number of injection stages, the injection start timing, the injection end timing, the injection amount, etc.) based on the operation amount of the accelerator pedal of the vehicle, the engine load, the engine speed NE, and the like. For example, the optimal injection state corresponding to the engine load and the engine speed is stored as an injection state map. Based on the current engine load and engine speed, the target injection state is calculated with reference to the injection state map.

  Injection command signals t1, t2, and tq (see FIG. 2A) corresponding to the calculated target injection state are set based on injection rate parameters td, te, and Rmax described in detail later. The learned values of these injection rate parameters are detected by the change in the detected value (pressure waveform) of the fuel pressure sensor 20.

  Next, a method for detecting and learning the injection rate parameter will be described below with reference to FIG. In the following description, learning is based on the detection value of the sensor 20 (# 1) when fuel is injected by the injection valve 10 (# 1). This is the same, and the injection rate parameter is learned based on the detection value of the fuel pressure sensor 20 mounted on the fuel injection valve 10 that is injecting.

  For example, when fuel is injected by the injection valve 10 (# 1), a change in fuel pressure caused by the injection is detected as a fuel pressure waveform (see FIG. 2C) based on the detection value of the sensor 20 (# 1). An injection state is detected by calculating an injection rate waveform (see FIG. 2B) representing a change in fuel injection amount per unit time based on the detected fuel pressure waveform. The injection rate parameters td, te, and Rmax that specify the detected injection rate waveform (injection state) are learned and used for injection control of the injection valve 10 (# 1).

  The detected value of the sensor 20 (# 1) shown in the fuel pressure waveform of FIG. 2 (c) starts to descend from the inflection point P1 as the injection starts and reaches the inflection point P2 as the maximum injection rate is reached. Descent ends. Thereafter, the lift starts at the inflection point P3 when the lift-down of the valve body 12 is started, and the lift ends at the inflection point P4 when the valve body 12 is closed and the injection is finished. Then, it attenuates while pulsating so as to repeat ascending and descending (refer to the inside of the one-dot chain line Wc). That is, the pressure wave remaining in the fuel pipe 42b and the high-pressure passage 11a after fuel injection reciprocates in the fuel pipe 42b and the high-pressure passage 11a to form a steady wave.

  Immediately after the fuel is injected, the fuel pressure in the entire injection system is reduced by that amount. Specifically, as shown in FIG. 2 (c), the fuel pressure decreases by a decrease amount ΔPc from the reference pressure Ps before the start of injection to the pressure Pe after the end of injection.

  This fuel pressure waveform has a correlation with the injection rate waveform shown in FIG. Specifically, the appearance time of the inflection point P1 and the injection start time R1 are correlated, the appearance time of the inflection point P3 and the injection end time R4 are correlated, and the pressure from the inflection point P1 to P2 There is a correlation between the drop amount ΔP and the maximum injection rate (injection rate parameter Rmax).

  FIG. 2A shows the injection command signal output to the injection valve 10 (# 1), and the above-described injection rate parameter td is a delay time (injection start delay) of the injection start timing R1 with respect to the injection start command timing t1. Time td). The injection rate parameter te is a delay time (injection end delay time te) of the injection end timing R4 with respect to the injection end command timing t2.

  Therefore, the correlation coefficients representing the various correlations described above are obtained by testing in advance, and using these correlation coefficients, the inflection points P1 and P3 detected from the fuel pressure waveform of the sensor 20 (# 1) are obtained. The injection rate parameters td, te, and Rmax are calculated based on the appearance time and the pressure drop amount ΔP. Further, the injection rate waveform can be estimated based on these injection rate parameters td, te, and Rmax, and the injection amount Q is based on the area of the estimated injection rate waveform (see the halftone hatch in FIG. 2B). Is calculated.

  As described above, by using the detected value of the fuel pressure sensor 20, it is possible to calculate and learn the actual injection state (injection rate parameters td, te, Rmax, injection amount Q, etc.) with respect to the injection command signal. Then, ECU 30 sets an injection command signal corresponding to the target injection state based on the learned value.

  Next, fuel property determination for determining the property of the fuel currently used in the fuel injection system will be described. FIG. 3 is a flowchart showing a processing procedure for fuel property determination. This series of processing is repeatedly executed at a predetermined cycle by the ECU 30 (fuel property determination device).

  First, fuel is injected by the fuel injection valve 10 (S11). Specifically, an injection command signal is output to the fuel injection valve 10 that has reached the injection timing to inject fuel. Subsequently, a pressure waveform indicating a change in fuel pressure is acquired based on the fuel pressure detected by the fuel pressure sensor 20 of the fuel injection valve 10 that is performing the fuel injection by the fuel injection valve 10 (S12). For example, when fuel is injected by the injection valve 10 (# 1), the change in fuel pressure caused by the injection is acquired as a pressure waveform (see FIG. 2C) based on the detection value of the sensor 20 (# 1). To do.

Subsequently, the velocity v of the pressure wave forming the pressure waveform is calculated based on the acquired pulsation period T of the pressure waveform and the length L of the fuel passage (S13). Specifically, as shown in a dashed-dotted line frame Wc in FIG. 2C, the period T is calculated by measuring one period of the pulsation portion generated after the fuel injection is completed in the pressure waveform. Then, in this period T, by dividing the double of the length L of the fuel pipe 42b and the high-pressure passage 11a (fuel passage), to calculate the velocity v of the pressure wave.

  Subsequently, a fuel pressure decrease amount ΔPc before and after fuel injection by the fuel injection valve 10 is calculated based on the acquired pressure waveform (S14). Specifically, as shown in FIG. 2C, the fuel pressure decrease amount ΔPc is calculated by subtracting the post-injection pressure Pe from the reference pressure Ps before the start of injection.

  Then, based on the acquired pressure waveform, the fuel injection amount Q by the fuel injection valve 10 is calculated (S15). Specifically, as described above, the injection rate waveform is estimated based on the injection rate parameters td, te, and Rmax, and the injection amount is based on the area of the estimated injection rate waveform (see the halftone dot hatching in FIG. 2B). Q is calculated. Note that the processing order of S13 to S15 can be arbitrarily changed.

  Subsequently, the fuel density ρ is calculated based on the speed v, the decrease amount ΔPc, the injection amount Q, and the volume V of the fuel passage calculated as described above (S16). Specifically, the density ρ is calculated by the following formula defined by fluid dynamics. The volume V of the fuel passage is the sum of the volume of the fuel pipe 42b and the volume of the high-pressure passage 11a. Note that “v ^ 2” means the square of v. ρ = ΔPc / (Q × v ^ 2).

  Subsequently, the kinematic viscosity ν of the fuel is calculated based on the calculated fuel density ρ (S17). Specifically, it is considered that there is a correlation between the density ρ of the fuel and the kinematic viscosity ν of the fuel, and this correlation is obtained in advance by experiments or the like. Then, using this correlation, the kinematic viscosity ν of the fuel is calculated from the density ρ of the fuel.

  Subsequently, it is determined whether or not the calculated kinematic viscosity ν of the fuel is smaller than a threshold value r (S18). Here, the smaller the kinematic viscosity ν of the fuel, the lower the lubricity by the fuel and the lower the characteristics of the fuel as a lubricating oil. The threshold value r is set to a value with which it can be determined whether or not the currently used fuel has an adverse effect on the driving of the fuel pump 41 and the fuel injection by the fuel injection valve 10.

  In the above determination, when it is determined that the calculated kinematic viscosity ν of the fuel is smaller than the threshold value r (S18: YES), a measure for the deterioration of the fuel property is performed (S19). Here, the fuel injection characteristics of the fuel injection valve 10 change according to the kinematic viscosity ν of the fuel. For this reason, the fuel injection state by the fuel injection valve 10 is controlled based on the calculated kinematic viscosity ν of the fuel. Specifically, the target injection state (the number of injection stages, the injection start timing, the injection end timing, the injection amount, etc.) is corrected according to the kinematic viscosity ν. Then, this series of processing is temporarily ended (END).

  On the other hand, in the above determination, when it is determined that the calculated kinematic viscosity ν of the fuel is not smaller than the threshold value r (S18: NO), this series of processes is temporarily ended (END). That is, it is determined that the fuel property has not deteriorated, and no measures are taken for the deterioration of the fuel property.

  The process of S12 corresponds to the process as the waveform acquisition unit, the process of S13 corresponds to the process as the speed calculation unit, the process of S14 corresponds to the process as the decrease amount calculation unit, and the process of S15 is the injection. The process of S16 corresponds to the process as a density calculation part, the process of S17 corresponds to the process as a kinematic viscosity calculation part, and the process of S18 corresponds to the process as a determination part. And the process of S19 is equivalent to the process as a control part.

  The embodiment described in detail above has the following advantages.

  A pressure waveform indicating a change in fuel pressure is acquired based on the fuel pressure detected by the fuel pressure sensor 20 when fuel is injected by the fuel injection valve 10. Based on the obtained pulsation period T of the pressure waveform and the length L of the fuel passage, the velocity v of the pressure wave forming the pressure waveform is calculated. That is, the pressure wave remaining in the fuel passage after fuel injection reciprocates in the fuel passage to form a stationary wave. For this reason, the velocity v of the pressure wave can be calculated on the basis of the pulsation period T (stationary wave oscillation period) of the pressure waveform and the length L of the fuel passage. In the standing wave, the position where the fuel pressure sensor 20 detects the fuel pressure in the fuel passage is arbitrary.

  The fuel density ρ is calculated based on the calculated pressure wave velocity v. That is, the fuel density ρ can be calculated based on the physical relationship between the pressure wave velocity v and the fuel density ρ. Further, the kinematic viscosity ν of the fuel is calculated based on the calculated fuel density ρ. That is, it is considered that there is a correlation between the density ρ of the fuel and the kinematic viscosity ν of the fuel, and this correlation can be obtained in advance by experiments or the like. Therefore, the kinematic viscosity ν of the fuel can be calculated from the density ρ of the fuel using this correlation.

  The kinematic viscosity ν of the fuel indicates the characteristics of the fuel as a lubricating oil, and therefore the quality of the fuel property can be determined based on the kinematic viscosity ν of the fuel. Thus, the fuel property can be determined by detecting the fuel pressure with the fuel pressure sensor 20 at the time of fuel injection. Therefore, it is possible to quickly determine the fuel property without adding a temperature sensor.

  Based on the acquired pressure waveform, a fuel pressure decrease amount ΔPc before and after fuel injection by the fuel injection valve 10 is calculated. Further, the fuel injection amount Q by the fuel injection valve 10 is calculated based on the acquired pressure waveform. The fuel density ρ is calculated based on the calculated pressure wave velocity v, the calculated fuel pressure decrease amount ΔPc, the calculated fuel injection amount Q, and the fuel passage volume V. That is, it is possible to calculate the fuel density ρ based on these physical relationships using only the acquired pressure waveform.

  The kinematic viscosity ν is calculated from the calculated density ρ using the correlation obtained in advance between the fuel density ρ and the kinematic viscosity ν. Therefore, the kinematic viscosity ν of the fuel can be easily calculated based on the calculated fuel density ρ.

· In the pulse period T of the obtained pressure waveform, by dividing twice the length L of the fuel passage, and calculates the velocity v of the pressure wave. Therefore, the velocity v of the pressure wave can be easily calculated based on the pulsation cycle T of the pressure waveform and the length L of the fuel passage.

  The fuel injection characteristics of the fuel injection valve 10 change according to the kinematic viscosity ν of the fuel. In this respect, the fuel injection state by the fuel injection valve 10 is controlled based on the calculated kinematic viscosity ν of the fuel. Therefore, it is possible to properly inject fuel according to the properties of the fuel.

  Note that the above-described embodiment may be modified as follows.

  -By analyzing the frequency of the acquired pressure waveform, the pulsation cycle T of the pressure wave can be calculated.

  -The fuel density ρ can also be calculated by the following equation. That is, the density ρ of the fuel can be calculated based on the bulk modulus K of the fuel and the pressure wave velocity v described above. ρ = K / v ^ 2.

  The bulk modulus K can be obtained in advance by experiments or the like. Also, the bulk modulus K can be calculated by the following formula. That is, the volume elastic modulus K can also be calculated based on the fuel pressure decrease amount ΔPc, the fuel injection amount Q, and the volume V of the fuel passage. ΔPc = K × Q / V.

  As described above, it is considered that there is a correlation between the fuel density ρ and the fuel kinematic viscosity ν. Therefore, the property of the fuel can be determined based on the calculated density ρ.

  -The fuel property determination apparatus mentioned above can also be applied not only to a diesel engine but to a gasoline direct injection engine provided with a delivery pipe.

  DESCRIPTION OF SYMBOLS 10 ... Fuel injection valve, 11a ... High pressure passage, 11b ... Injection hole, 20 ... Fuel pressure sensor, 30 ... ECU, 42 ... Common rail, 42b ... Fuel piping.

Claims (4)

A fuel pump (41) for pumping fuel, a pressure accumulating container (42) for accumulating and holding the fuel pumped by the fuel pump, a fuel injection valve (10) for injecting the fuel from the injection hole (11b), A fuel property applied to a fuel injection system comprising a fuel passage (42b, 11a) through which the fuel flows from the pressure accumulating container to the injection hole, and a fuel pressure sensor (20) for detecting fuel pressure in the fuel passage. A determination device (30) comprising:
A waveform acquisition unit for acquiring a pressure waveform indicating a change in the fuel pressure based on the fuel pressure detected by the fuel pressure sensor when the fuel is injected by the fuel injection valve;
A speed calculation unit that calculates a speed of a pressure wave forming the pressure waveform based on a pulsation period of the pressure waveform acquired by the waveform acquisition unit and a length of the fuel passage;
A density calculator that calculates the density of the fuel based on the speed calculated by the speed calculator;
A kinematic viscosity calculating unit that calculates a kinematic viscosity of the fuel based on the density calculated by the density calculating unit;
A determination unit for determining whether the kinematic viscosity calculated by the kinematic viscosity calculation unit is smaller than a threshold for determining whether the lubricity due to the fuel decreases and adversely affects the driving of the fuel pump ;
When the determination unit determines that the kinematic viscosity is smaller than the threshold, the fuel injection state by the fuel injection valve is controlled based on the kinematic viscosity, and the kinematic viscosity is determined by the determination unit. A control unit that does not control the injection state based on the kinematic viscosity when it is determined that it is not smaller than,
A fuel property determining apparatus comprising: Based on the pressure waveform acquired by the waveform acquisition unit, a decrease amount calculation unit that calculates a decrease amount of the fuel pressure before and after the fuel injection by the fuel injection valve;
An injection amount calculation unit that calculates an injection amount of the fuel by the fuel injection valve based on the pressure waveform acquired by the waveform acquisition unit;
With
The density calculation unit includes the speed calculated by the speed calculation unit, the decrease amount calculated by the decrease amount calculation unit, the injection amount calculated by the injection amount calculation unit, and the volume of the fuel passage. based on fuel property determining apparatus according to claim 1 for calculating the density of the fuel. 3. The kinematic viscosity calculation unit according to claim 1, wherein the kinematic viscosity calculation unit calculates the kinematic viscosity from the density calculated by the density calculation unit using a correlation obtained in advance between a fuel density and a kinematic viscosity. Fuel property determination device. The velocity calculation unit is a pulse period of the pressure waveform obtained by the waveform obtaining unit, by dividing the double of the length of the fuel passage, it claims 1-3 to calculate the rate of 1 The fuel property determination device according to item.

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