Method for controlling viscosity in fuel control system by using vibration indicator

Abstract

To provide a method for controlling viscosity in a fuel control system by using a vibration indicator.SOLUTION: The method includes a step of supplying a fuel to a vibration indicator 5, a step of measuring characteristics of the fuel by using the vibration indicator 5, and a step of generating a signal on the basis of the measured characteristics of the fuel. The method further includes a step of applying a signal to a temperature control unit 420 configured to control a temperature of the fuel to be supplied to the vibration indicator 5.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The embodiments described below relate to fuel control systems, and more particularly to a method of controlling viscosity in a fuel control system using a vibrometer. [Background technology]

[0002] Heavy fuel oil (HFO) is used as a fuel for engines in the marine industry. Engine performance correlates with how well the fuel injectors atomize the fuel. The fuel injectors are controlled by a controller, typically an engine control unit (ECU), to ensure that the atomization is adequate to achieve the desired performance. For example, the ECU can detect various parameters such as intake air pressure, fuel pressure, and fuel temperature, and from these parameters control the fuel injectors to increase or decrease the flow rate of fuel into the combustion chamber.

[0003] The characteristics of a fuel can determine whether the fuel is suitable for a given fuel injector. For example, a cold fuel may have a viscosity that is too high for a fuel injector. Fuel injectors generally cannot effectively atomize high viscosity fuels or can only atomize fuels within a certain viscosity range. This is especially true for HFOs, which have a high viscosity compared to other common fuels such as gasoline or other distillates.

[0004] However, the marine industry has developed advanced engine configurations and fuel control systems that can utilize HFO and other fuels despite a wide range of fuel supply viscosities. These engine configurations and fuel control systems employ a variety of techniques. For example, engine configurations include heaters to heat the fuel to reduce the viscosity of the fuel. However, the fuel is typically heated in close proximity to the fuel source, which can be problematic because fuel control systems typically have long fuel supply lines that cool the fuel before it reaches the engine. Furthermore, the cooling rate along the fuel lines can vary significantly due to changing environmental conditions around the fuel lines. As a result, the viscosity of the fuel when it reaches the engine may be unsuitable for the fuel injectors.

[0005] However, if the fuel properties are measured with the desired accuracy achievable using a vibrometer, the viscosity of the fuel can be controlled. Thus, there is a need to control the viscosity of the fuel in a fuel control system using a vibrometer. There is also a need to control the viscosity to compensate for heat losses along the fuel lines. Summary of the Invention

[0006] A method for controlling the viscosity of fuel in a fuel control system using a vibrometer is provided. According to one embodiment, the method includes providing fuel to a vibrometer, measuring a property of the fuel with the vibrometer, generating a signal based on the measured property of the fuel, and providing the signal to a temperature control unit configured to control a temperature of the fuel applied to the vibrometer.

[0007] A vibrometer for controlling viscosity in a fuel control system is provided. According to one embodiment, the vibrometer comprises a meter assembly fluidly coupled to a fluid source and meter electronics communicatively coupled to the meter assembly. The meter electronics is configured to measure a property of the fuel with the meter assembly, generate a signal based on the measured property, and provide the signal to a temperature control unit configured to control a temperature of the fuel provided to the vibrometer.

[0008] A fuel control system configured to control viscosity within the fuel control system is provided. According to one embodiment, the fuel control system includes a vibrometer fluidly and communicatively coupled to a temperature control unit, and a temperature control unit configured to receive fuel from a fluid source and communicatively and fluidly coupled to the vibrometer. The temperature control unit is configured to receive a signal from the vibrometer and to control a temperature of the fuel based on the signal received from the vibrometer.

[0009] Aspects According to one aspect, a method of controlling viscosity of fuel in a fuel control system using a vibrometer includes supplying fuel to the vibrometer, measuring a property of the fuel with the vibrometer, generating a signal based on the measured property of the fuel, and providing the signal to a temperature control unit configured to control a temperature of the fuel applied to the vibrometer.

[0010] Preferably, the method further comprises the step of providing a signal from the vibrometer to a fuel injection controller configured to control an engine receiving fuel. Preferably, the step of generating a signal based on a measured property of the fuel comprises: Reference Value and comparing the measured characteristic value with Reference Value generating a signal proportional to the difference between Preferably, the temperature control unit includes a heater configured to heat the fuel to reduce the viscosity of the fuel.

[0011] Preferably, the step of generating a signal based on the measured property of the fuel comprises the step of calculating the viscosity from the measured property of the fuel. Preferably, the measured property of the fuel is the density of the fuel. Preferably, the vibrometer is a Coriolis flowmeter.

[0012] According to one embodiment, a method for controlling viscosity within a fuel control system (400) is provided. For The vibrometer (5) comprises a meter assembly (10) fluidly coupled to a fuel source (410) and meter electronics (20) communicatively coupled to the meter assembly (10), the meter electronics (20) configured to measure a property of the fuel using the meter assembly (10), generate a signal based on the measured property, and provide the signal to a temperature control unit (420) configured to control the temperature of the fuel provided to the vibrometer (5).

[0013] Preferably, the meter electronics (20) is further configured to provide a signal from the vibrometer to a fuel injection controller (432) configured to control an engine (439) that receives fuel. Preferably, the meter electronics (20) configured to generate a signal based on the measured characteristic is adapted to calculate the measured characteristic value. Reference Value and the measured characteristic value and Reference Value The sensor is configured to generate a signal proportional to the difference between the

[0014] Preferably, the temperature control unit (420) includes a heater (424) configured to heat the fuel to reduce the viscosity of the fuel. Preferably, the meter electronics (20), which is configured to generate a signal based on the measured property of the fuel, is configured to calculate the viscosity from the measured property of the fuel. Preferably, the measured property of the fuel is the density of the fuel. Preferably, the vibrometer is a Coriolis flowmeter.

[0015] According to one aspect, a fuel control system (400) configured to control the viscosity of a fuel in the fuel control system (400) includes a vibrometer (5) fluidly and communicatively coupled to a temperature control unit (420), and the temperature control unit (420) configured to receive fuel from a fluid source (410) and communicatively and fluidly coupled to the vibrometer (5), the temperature control unit (420) configured to receive a signal from the vibrometer (5) and control a temperature of the fuel based on the signal received from the vibrometer (5).

[0016] Preferably, the vibrometer (5) is configured to measure a property of the fuel and to determine the viscosity of the fuel from the measured property. Preferably, the vibration meter (5) Reference Value and providing a signal to the temperature control unit (420). Reference Value to the temperature control unit (420). [Brief description of the drawings]

[0017] Like numbers represent like elements throughout the drawings. It should be understood that the drawings are not to scale. [Figure 1] FIG. 1 shows a vibrometer 5 for controlling the viscosity of a fuel in a fuel control system according to an embodiment. [Diagram 2] FIG. 2 shows a viscosity-density graph 200 along with data illustrating the relationship between viscosity and density of a fuel. [Diagram 3] FIG. 3 shows a temperature-viscosity graph 300 illustrating the relationship between temperature and viscosity of a fuel. [Figure 4] FIG. 4 shows a fuel control system 400 including a vibrometer 5 for controlling the viscosity of the fuel. [Diagram 5] FIG. 5 illustrates a method of controlling the viscosity of fuel in a fuel control system using a vibrometer, according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1-5 and the following description provide specific examples to teach those skilled in the art how to make and use the best mode of the embodiments of the use of a vibration meter to control the viscosity of fuel in a fuel control system. For the purpose of teaching the inventive principles of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will recognize variations from these examples that fall within the scope of the present invention. Those skilled in the art will recognize that the features described below can be combined in various ways to form numerous variations of the present invention of the use of a vibration meter to control the viscosity of fuel in a fuel control system. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents.

[0019] FIGURE 1 illustrates a vibrometer 5 for controlling the viscosity of fuel in a fuel control system according to an embodiment. As shown in FIGURE 1, the vibrometer 5 includes a meter assembly 10 and meter electronics 20. The meter assembly 10 is responsive to the mass flow rate and density of a process material. The meter electronics 20 is connected to the meter assembly 10 via lead 100 and provides density, mass flow rate, and temperature information, as well as other information, via path 26. Although a Coriolis type flow meter structure is described, it will be apparent to one skilled in the art that the present invention may be embodied as a vibrating tube densitometer, tuning fork densitometer, and the like.

[0020] The meter assembly 10 includes a flange 103, 103' having a pair of manifolds 150, 150' and flange necks 110, 110', a pair of parallel flow tubes 130, 130', a drive mechanism 180, a resistance temperature detector (RTD) 190, and a pair of pick-off sensors 170l, 170r. The flow tubes 130, 130' have two essentially straight inlet legs 131, 131' and outlet legs 134, 134' that converge toward each other at the flow tube mounting blocks 120, 120'. The flow tubes 130, 130' are bent at two symmetrical points along their length and are generally parallel throughout their length. The brace bars 140, 140' serve to define axes W and W' about which the flow tubes 130, 130' oscillate. Legs 131, 131' and 134, 134' of flow tubes 130, 130' are fixedly attached to flow tube mounting blocks 120, 120' which are in turn fixed to manifolds 150, 150'. This provides a continuous, closed material path through meter assembly 10.

[0021] When flanges 103, 103' having holes 102, 102' are connected via inlet end 104 and outlet end 104' to a process line (not shown) carrying the process material to be measured, the material enters the flowmeter at inlet end 104 through orifice 101 in flange 103 and is directed through manifold 150 to flow tube mounting block 120 having surface 121. Within manifold 150 the material is split and directed through flow tubes 130, 130'. Upon exiting flow tubes 130, 130' the process material passes through block 120' having surface 121' and Bima The streams are recombined into a single stream in a nifold 150' and then directed to an outlet end 104' connected by a flange 103' having holes 102' for delivery to a process line (not shown).

[0022] The flow tubes 130, 130' are selected to have approximately the same mass distribution, moment of inertia about bending axes WW and W'-W', and Young's modulus, respectively, and are appropriately mounted to the flow tube mounting blocks 120, 120'. These bending axes pass through the brace bars 140, 140'. Because the Young's modulus of the flow tube changes with temperature, which affects flow and density calculations, an RTD 190 is attached to the flow tube 130' to continuously measure the temperature of the flow tube 130'. The temperature of the flow tube 130', and therefore the voltage appearing across the RTD 190 for a given current passing through the RTD, is governed by the temperature of the material passing through the flow tube 130'. The temperature dependent voltage appearing across the RTD 190 is used by the meter electronics 20 in a well known manner to compensate for changes in the elastic modulus of the flow tubes 130, 130' due to changes in the temperature of the flow tube. The RTD 190 is connected to the meter electronics 20 by leads 195.

[0023] Both flow tubes 130, 130' are driven on either side about their respective bending axes W and W' by a drive mechanism 180, referred to as the first out-of-phase bending mode of the flowmeter. This drive mechanism 180 may include any one of a number of well known configurations, such as a magnet attached to flow tube 130' and opposing coils attached to flow tube 130, through which an alternating current is passed to vibrate both flow tubes 130, 130'. An appropriate drive signal is applied to drive mechanism 180 by meter electronics 20 via leads 185.

[0024] Meter electronics 20 receives the RTD temperature signal on lead 195 and the left and right sensor signals appearing on leads 165l and 165r, respectively. Meter electronics 20 generates a drive signal appearing on lead 185 to drive mechanism 180 to vibrate tubes 130, 130'. Meter electronics 20 processes the left and right sensor signals and the RTD signals to calculate the mass flow rate and density of material passing through meter assembly 10. This information, along with other information, is applied as a signal by meter electronics 20 via path 26.

[0025] As described in more detail below, the signal may be used to control the viscosity of the fuel in the fuel system. For example, the signal may be used to control the temperature of the fuel in the fuel system. By controlling the temperature of the fuel, the fuel delivered to the engine is within a desired viscosity range. The signal may be generated based on a property such as density measured by a vibrometer 5, as described in more detail below.

[0026] 2 shows a viscosity-density graph 200 with data illustrating the relationship between viscosity and density of a fuel. Viscosity-density graph 200 includes a viscosity axis 210 having a logarithmic scale ranging from 1.00E-02 to 1.00E-03 centistokes (cSt). Viscosity-density graph 200 also includes a density axis 220 ranging from 600.00 kg / m3 to 1100.00 kg / m3. The viscosity-density relationship of the fuel is expressed in units of centistokes and kg / m3, respectively, although other units may be used in alternative embodiments.

[0027] Viscosity-density graph 200 shows line 240, which is a linear fit to viscosity-density data points 250, which are plotted as circles. Line 240 may be calculated from viscosity-density data points 250 using any suitable method, such as, for example, linear regression. Line 240 may be stored as a data set, equation, or the like within meter electronics 20. Viscosity-density data points 250 may be determined by a variety of means including, for example, measuring the viscosities and densities of various types of fuels over a range of temperatures.

[0028] As can be seen from FIG. 2, line 240 is an approximation of viscosity-density data points 250. In other words, viscosity-density data points 250 are relatively close to line 240 along the entire length of the line. Thus, line 240 may be used to provide a relationship within an accurate range between the density and viscosity of a fuel. The viscosity of a fuel may be determined from the density of the fuel using a viscosity-density relationship. For example, a vibrometer 5 may measure the density of the fuel within the vibrometer 5. Using the measured density of the fuel, line 240 may be used to determine the corresponding viscosity of the fuel. Other fuel properties, such as temperature, may be correlated to the viscosity of the fuel.

[0029] 3 illustrates a temperature-viscosity graph 300 illustrating the relationship between temperature and viscosity of a fuel. The temperature-viscosity graph 300 includes a temperature axis 310 and a viscosity axis 320. The temperature axis 310 is in degrees Celsius (°C) and the viscosity axis 320 is in centistokes (cSt). The viscosity axis 320 is shown on a logarithmic scale. In alternative embodiments, any suitable units and scales may be used.

[0030] The temperature-viscosity graph 300 also includes a temperature-viscosity plot 330 that declines as the temperature increases. The temperature-viscosity plots 330 include a high viscosity fuel plot 332, a medium viscosity fuel plot 334, and a low viscosity fuel plot 336. Each temperature-viscosity plot 330 represents a particular grade of fuel, with fuel grades having different viscosities. The temperature-viscosity plots 330 may be obtained in any suitable manner, such as, for example, by querying empirical data for fuel delivered to a tank, by referencing a table having viscosity-fuel grade data, etc. The temperature-viscosity graph 300 also shows a low temperature viscosity region 330a and an operating viscosity region 330b.

[0031] The low temperature viscosity region 330a is the viscosity of the fuel when the fuel is not heated. For example, the low temperature viscosity region 330a represents the fuel when the fuel is in a tank. As can be seen from FIG. 3, the low temperature viscosity region 330a has a relatively wide viscosity range of the temperature-viscosity plot 330 at a given temperature. For example, at 40 degrees Celsius, the high viscosity fuel plot 332 has a viscosity of 2000 centistokes. The low viscosity fuel plot 336 has a viscosity of about 700 centistokes at 40 degrees Celsius. Thus, the difference between the high viscosity fuel plot 332 and the low viscosity fuel plot 336 at 40 degrees Celsius is about 1300 centistokes.

[0032] In contrast, the operating viscosity region 330b has a narrower range of viscosities. For example, at 140 degrees Celsius, the high viscosity fuel plot 332 has a viscosity of 20 centistokes. The low viscosity fuel plot 336 at 140 degrees Celsius has a viscosity of approximately 15 centistokes. Thus, instead of a 1300 centistokes difference at 40 degrees Celsius, the difference between the high viscosity fuel plot 332 and the low viscosity fuel plot 336 at 140 degrees Celsius is approximately 5 centistokes. Thus, the different fuel grades within the operating viscosity region 330b may have characteristics such as viscosities suitable for fuel injectors in a fuel control system, as described in more detail below.

[0033] FIG 4 illustrates a fuel control system 400 with a vibration meter 5 for controlling the viscosity of the fuel. The fuel control system 400 includes a fuel source 410 in fluid communication with a temperature control unit 420, a vibration meter 5 as described with respect to FIG 1, and a fuel injection system 430. The temperature control unit 420 is fluidly coupled to the vibration meter 5 via a fuel line 425, the length of which is shown in dashed lines. The temperature control unit 420 is also communicatively connected to the vibration meter 5 via a communication path 429, which may be part of the path 26 described with reference to FIG 1.

[0034] 4, fuel source 410 includes a fuel port 412 and a tank 414. Shown adjacent fuel port 412 is an arrow indicating that fuel is provided to fuel port 412. Tank 414 is fluidly coupled to fuel port 412 and configured to receive the fuel provided to fuel port 412. Tank 414 is shown as being partially filled with fuel (an exemplary fuel level is shown with a wavy line). Near the bottom of tank 414 is a fuel line that fluidly connects tank 414 to temperature control unit 420.

[0035] The temperature control unit 420 includes a temperature controller 422 electrically coupled to a heater 424 configured to heat the fuel as it flows through the heater 424. The temperature controller 422 is also communicatively connected to a viscometer 426 in the vibrometer 5, a temperature transducer 428, and the meter electronics 20. As can be seen from FIG. 4 , fuel can flow from the tank 414 through the heater 424 and the viscometer 426 to a fuel line 425. The temperature transducer 428 can measure the temperature of the fuel and provide a signal to the temperature controller 422.

[0036] The temperature controller 422 is configured to provide power, such as electrical power, to the heater 424. The power provided to the heater 424 is proportional to the heat transferred from the heater 424 to the fuel flowing through the heater 424. The power provided to the heater 424 is proportional to the temperature measured by the temperature transducer 428 and the temperature of the fuel. reference temperature is proportional to the difference between

[0037] The temperature controller 422 may also receive a signal containing information regarding the fuel flowing through the viscometer 426. For example, the temperature controller 422 may receive a voltage signal from the viscometer 426 that is proportional to the viscosity of the fuel. Alternatively, the viscometer 426 may provide a digital value representing the viscosity of the fuel. In alternative embodiments, other means of providing information to the temperature controller 422 may be used. Similarly, the temperature controller 422 may receive a signal from a temperature transducer 428 that contains information regarding the temperature of the fuel flowing through the fuel line 425. The measured temperature may be the temperature of the fuel, the fuel line, the ambient air, etc.

[0038] Although the above describes an embodiment of the temperature control unit 420 including a temperature controller 422, a heater 424, a viscometer 426, and a temperature transducer 428, alternative embodiments may have different configurations. For example, an embodiment may not include the viscometer 426, and may instead rely on a vibrometer 5 to determine the viscosity of the fuel.

[0039] However, the viscometer 426 is advantageous because it can measure the viscosity of the fuel as it leaves the heater 424 and provide information regarding the viscosity to the temperature controller 422 and / or the meter electronics 20, which compares the viscosity to measurements by the meter assembly 10. It will also be appreciated that the temperature controller 422 need not be part of the temperature control unit 420. For example, the temperature control unit 420 may be part of the meter electronics 20 of the vibrometer 5 previously described with reference to FIG.

[0040] 4, the vibrometer 5 is shown with meter electronics 20 communicatively coupled to the meter assembly 10. The meter electronics 20 is also shown communicatively coupled to a temperature control unit 420 and a fuel injection system 430. The meter electronics 20 may be configured to provide signals to the temperature control unit 420 and / or the fuel injection system 430. For example, the meter electronics 20 may receive measurements, such as fuel density, within the meter assembly 10 and send them to the temperature control unit 420 and / or the fuel injection system 430. Reference Value can be calculated.

[0041] Fuel injection system 430 is shown as including a fuel injection controller 432 that is communicatively coupled to meter electronics 20. Fuel injection controller 432 is also communicatively coupled to a fuel pump 434 and a fuel injector 438. Fuel pump 434 is fluidly coupled to fuel injector 438 via a fuel distributor 436. Fuel pump 434 is configured to provide fuel at a constant pressure to fuel injector 438 via fuel distributor 436. Fuel injector 438 injects fuel into engine 439.

[0042] The fuel injection controller 432 is configured to control parameters of the fuel injection system 430. For example, the fuel injection controller 432 may regulate the pressure of the fuel exiting the fuel pump 434. Thus, the pressure at the fuel injector 438 may be at a desired value. Other parameters, such as operating parameters of the fuel injector 438, may also be controlled.

[0043] 4, the fuel injection controller 432 can control parameters of the fuel injection system 430 based on signals received from the meter electronics 20. For example, the meter electronics 20 can generate and provide signals with information about the fuel flowing through the meter assembly 10. The information can include, for example, the density, viscosity, and temperature of the fuel. Using the information, the fuel injection controller 432 can determine desired operating parameters of the fuel injection system 430. For example, the fuel injection controller 432 can adjust the pressure of the fuel exiting the fuel pump 434 based on the viscosity of the fuel.

[0044] In alternative embodiments, the fuel injection system 430 may not be in communication with the meter electronics 20. Thus, the fuel injection system 430 may not receive information regarding the viscosity or temperature of the fuel. In these or other embodiments, the fuel control system 400 may control the viscosity of the fuel, as described in more detail below.

[0045] FIG. 5 illustrates a method 500 for controlling the viscosity of fuel in a fuel control system using a vibrometer according to an embodiment. Method 500 begins at step 510 by supplying fuel to a vibrometer. For example, with reference to fuel control system 400 described above, method 500 supplies fuel from a fuel source 410 to a vibrometer 5 via a temperature control unit 420. At step 520, a property of the fuel is measured by the vibrometer. The property of the fuel includes density, temperature, etc. At step 530, method 500 generates a signal based on the measured property of the fuel. For example, the generated signal may be based on a viscosity calculated from a density measurement using a relationship between the fuel properties. At step 540, method 500 provides the generated signal to a temperature control unit, such as temperature control unit 420 described above with reference to FIG. 4.

[0046] For example, with reference to the embodiment shown in FIG. 2, line 240 is used to determine the viscosity from the measured density. Meter electronics 20 may receive the measured density of the fuel via lead 100 as described with reference to FIG. 1. The measured density may be used as a dependent variable in calculating a corresponding determined viscosity. The measured density may be used as received by meter electronics 20 or may be stored within meter electronics 20 for later use. Using the measured density and line 240 as described above, the viscosity of the fuel within meter assembly 10 is determined. The determined viscosity may be: Reference Value is used to calculate

[0047] Reference Value compensates for the distance between the temperature control unit 420 and the vibration meter 5. As mentioned above, the distance between the temperature control unit 420 and the vibration meter 5 is shown in FIG. 4 as a dashed line in the fuel line 425. This distance allows the fuel to cool after being heated by the heater 424. Therefore, Reference Value may compensate for cooling of the fuel as it flows through the fuel line 425. Other factors, such as, for example, the mass flow rate of the fuel through the fuel line 425, may also be compensated for.

[0048] Reference Value may be provided by meter electronics 20 to temperature control unit 420 via a generated signal. For example, meter electronics 20 may Reference Value and modulating the signal using the digital representation. Thus, the generated signal provided by meter electronics 20 is Reference Value For example, Reference Value Other methods can be used, such as an analog direct current (DC) voltage proportional to the measured value. Reference Value can be proportional to the difference between

[0049] Provided by meter electronics 20 Reference Valuemay be any suitable value that can be used to control the viscosity of the fuel. For example, Reference Value teeth Reference viscosity That is, meter electronics 20 may determine the viscosity from the measured density of the fuel in meter assembly 10 and, by using the measured temperature provided by temperature control unit 420, one of temperature-viscosity plots 330. Reference viscosity The temperature control unit 420 can calculate, for example, using one of the temperature-viscosity plots 330 shown in FIG. Reference viscosity from reference temperature can be calculated.

[0050] In an alternative embodiment, the signal provided by the meter electronics 20 Reference Value teeth, reference temperature In this embodiment, the meter electronics 20 is reference temperature to the temperature control unit 420. The temperature control unit 420 reference temperature and refueling the fuel by the heater 424. reference temperature Additionally or alternatively, the meter electronics 20 may be Reference Value can be provided.

[0051] reference temperature Using , the temperature control unit 420 can use any suitable control means, such as, for example, a proportional-integral-derivative (PID) control algorithm. For example, the control means may be provided by the meter electronics 20 or determined by the temperature control unit 420. reference temperature is compared to the temperature measured by the temperature transducer 428 and the amount of power supplied to the heater 424 is adjusted based on the comparison. reference temperature and the measured temperature.

[0052] Since the vibration meter 5 is in a fuel control system 400 that is in a different location from the temperature control unit 420, the temperature control unit 420 is provided with reference temperatureis not the same as the desired temperature of the fuel flowing through the meter assembly 10. This temperature difference is proportional to the distance between the temperature control unit 420 and the vibration meter 5. The distance between the temperature control unit 420 and the vibration meter 5 is, for example, 100 meters, although any distance may exist in alternative embodiments. Thus, reference temperature is higher than the desired fuel temperature at the vibrometer 5.

[0053] The above-described embodiment uses a vibrometer 5 to control the viscosity of the fuel in the fuel control system 400. As explained above, the viscosity of the fuel in the fuel control system 400 is controlled by controlling the temperature of the fuel. The temperature can be controlled, for example, by a temperature control unit 420 having a heater 424. The heater 424 heats the fuel by reference temperature Thus, the fuel entering the fuel injection system 430 has suitable fuel properties. For example, the viscosity of the fuel in the fuel injection system 430 is within the operating viscosity region 330b shown in FIG.

[0054] In some embodiments, the determined viscosity may be provided to the fuel injection system 430. For example, the fuel injection controller 432 may use the determined viscosity to control various parameters within the fuel injection system 430. Thus, the fuel pump 434 and the fuel injectors 438 may be controlled in a manner appropriate for the fuel received by the fuel injection system 430. For example, the fuel pressure of the fuel leaving the fuel pump 434 may be appropriate for the viscosity determined by the vibration meter 5.

[0055] The detailed description of the above embodiments is not a complete description of all embodiments contemplated by the inventors within the scope of the present description. Indeed, one of ordinary skill in the art will recognize that certain elements of the above embodiments may be combined in various ways or removed to create further embodiments, and such further embodiments are within the scope and disclosure of the present description. It will also be apparent to one of ordinary skill in the art that all or part of the above embodiments may be combined to produce further embodiments within the scope and disclosure of the present description.

[0056] Thus, although specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present description, as those skilled in the art will recognize. do. The disclosure provided herein is applicable to other vibrometers for controlling fuel in a fuel control system, and not just the embodiments described above and shown in the accompanying drawings, and therefore the scope of the above embodiments should be determined from the appended claims.

Claims

1. 1. A method for controlling viscosity of fuel in a fuel control system using a Coriolis flow meter, comprising: measuring a temperature of the fuel with a temperature control unit connected to a fuel line connecting an engine to a fuel source and located upstream of the Coriolis flow meter in the fuel line to the engine; supplying the fuel to the Coriolis flowmeter via the fuel line, the fuel line including a distance between the temperature control unit and the Coriolis flowmeter that cools the fuel; measuring the density of the fuel using the Coriolis flowmeter; determining a viscosity of the fuel based on a measured density of the fuel and an empirically determined relationship between viscosity and density for the fuel; determining a reference value, which is a reference viscosity or a reference temperature, based on the determined viscosity of the fuel and the measured temperature of the fuel, the reference value being smaller or larger than a desired value for the fuel in the Coriolis flow meter and compensating for cooling of the fuel as it flows through the fuel line to the engine; providing the reference value to the temperature control unit configured to control a temperature of the fuel applied to the Coriolis flowmeter; and controlling the viscosity of the fuel in the engine by controlling a temperature of the fuel based on the reference value using the temperature control unit.

2. The method of claim 1 , wherein the temperature control unit includes a heater configured to heat the fuel to reduce a viscosity of the fuel.

3. A Coriolis flow meter (5) for controlling viscosity in a fuel control system (400), comprising: a meter assembly (10) fluidly coupled to a fuel source (410) via a fuel line (425) to an engine (439), the fuel line (425) including a fuel cooling distance between the Coriolis flow meter (5) and a temperature control unit (420), the temperature control unit (420) being located in the fuel line (425) upstream of the Coriolis flow meter (5) and configured to control a temperature of the fuel provided to the Coriolis flow meter (5); meter electronics (20) communicatively coupled to the meter assembly (10); The meter electronics (20) include: measuring the density of the fuel with the meter assembly (10); determining a viscosity of the fuel based on the measured density of the fuel and an empirically determined relationship between viscosity and density for the fuel; determining a reference value, which is a reference viscosity or a reference temperature, based on the determined viscosity of the fuel and the temperature of the fuel measured by the temperature control unit (420), said reference value being smaller or larger than a desired value for the fuel in the Coriolis flow meter (5) and compensating for cooling of the fuel as it flows through the fuel line (425) to the engine (439); and providing the reference value to the temperature control unit (420); The temperature control unit (420) Measuring a temperature of the fuel; and and controlling the temperature and viscosity of the fuel provided to the Coriolis flow meter (5) based on the reference value, thereby controlling the viscosity of the fuel in the engine (439).

4. 4. The Coriolis flowmeter of claim 3, wherein the temperature control unit comprises a heater configured to heat the fuel to reduce a viscosity of the fuel.

5. A fuel control system (400) configured to control a viscosity of a fuel within the fuel control system (400), comprising: a Coriolis flow meter (5) fluidly and communicatively coupled to the temperature control unit (420) and configured to measure the density of the fuel flowing through the fuel line (425) to the engine (439); a temperature control unit (420) configured to receive the fuel from a fluid source (410) via the fuel line (425) to the engine (439), the temperature control unit (420) communicatively and fluidly coupled to the Coriolis flowmeter (5) and positioned upstream of the Coriolis flowmeter (5) in the fuel line (425), the fuel line (425) including a distance between the temperature control unit (420) and the Coriolis flowmeter (5) for cooling the fuel; The temperature control unit (420) Measuring a temperature of the fuel; and receiving a reference value determined by the Coriolis flowmeter from the Coriolis flowmeter; and controlling a temperature of the fuel based on the reference value, thereby controlling a viscosity of the fuel in the engine (439). The reference value is a reference viscosity or a reference temperature, the reference value is determined based on a viscosity of the fuel and a temperature of the fuel measured by the temperature control unit (420); the reference value is less than or greater than a desired value for the fuel in the Coriolis flowmeter (5); the reference value compensates for cooling of the fuel as it flows through the fuel line (425) to the engine (439); The viscosity of the fuel used in determining the reference value is based on a measured density of the fuel and an empirically determined relationship between viscosity and density for the fuel, the fuel control system (400).

6. The Coriolis flowmeter (5) 6. The fuel control system of claim 5, configured to determine a viscosity of the fuel used in determining the reference value from a measured density of the fuel.

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