SE540249C2 - A method for determining the functionality of a pressure regulator and a liquefied gas fuel system - Google Patents

A method for determining the functionality of a pressure regulator and a liquefied gas fuel system

Info

Publication number
SE540249C2
SE540249C2 SE1651690A SE1651690A SE540249C2 SE 540249 C2 SE540249 C2 SE 540249C2 SE 1651690 A SE1651690 A SE 1651690A SE 1651690 A SE1651690 A SE 1651690A SE 540249 C2 SE540249 C2 SE 540249C2
Authority
SE
Sweden
Prior art keywords
gas
storage device
fuel gas
gas storage
pressure
Prior art date
Application number
SE1651690A
Other versions
SE1651690A1 (en
Inventor
Gralde Marcus
Löthgren Svante
Original Assignee
Scania Cv Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scania Cv Ab filed Critical Scania Cv Ab
Priority to SE1651690A priority Critical patent/SE540249C2/en
Priority to DE102017011349.1A priority patent/DE102017011349A1/en
Publication of SE1651690A1 publication Critical patent/SE1651690A1/en
Publication of SE540249C2 publication Critical patent/SE540249C2/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0203—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels characterised by the type of gaseous fuel
    • F02M21/0215—Mixtures of gaseous fuels; Natural gas; Biogas; Mine gas; Landfill gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/021—Control of components of the fuel supply system
    • F02D19/022—Control of components of the fuel supply system to adjust the fuel pressure, temperature or composition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/025—Failure diagnosis or prevention; Safety measures; Testing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/026—Measuring or estimating parameters related to the fuel supply system
    • F02D19/027—Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0027—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures the fuel being gaseous
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0203—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels characterised by the type of gaseous fuel
    • F02M21/0209—Hydrocarbon fuels, e.g. methane or acetylene
    • F02M21/0212—Hydrocarbon fuels, e.g. methane or acetylene comprising at least 3 C-Atoms, e.g. liquefied petroleum gas [LPG], propane or butane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0221—Fuel storage reservoirs, e.g. cryogenic tanks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/023—Valves; Pressure or flow regulators in the fuel supply or return system
    • F02M21/0239—Pressure or flow regulators therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0287—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers characterised by the transition from liquid to gaseous phase ; Injection in liquid phase; Cooling and low temperature storage
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0293—Safety devices; Fail-safe measures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/02—Special adaptations of indicating, measuring, or monitoring equipment
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C9/00—Methods or apparatus for discharging liquefied or solidified gases from vessels not under pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
    • F17C2201/05—Size
    • F17C2201/054—Size medium (>1 m3)
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
    • F17C2201/05—Size
    • F17C2201/056—Small (<1 m3)
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2205/00—Vessel construction, in particular mounting arrangements, attachments or identifications means
    • F17C2205/03—Fluid connections, filters, valves, closure means or other attachments
    • F17C2205/0302—Fittings, valves, filters, or components in connection with the gas storage device
    • F17C2205/0338—Pressure regulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2221/00—Handled fluid, in particular type of fluid
    • F17C2221/03—Mixtures
    • F17C2221/032—Hydrocarbons
    • F17C2221/033—Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
    • F17C2223/0146—Two-phase
    • F17C2223/0153—Liquefied gas, e.g. LPG, GPL
    • F17C2223/0161—Liquefied gas, e.g. LPG, GPL cryogenic, e.g. LNG, GNL, PLNG
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
    • F17C2223/033—Small pressure, e.g. for liquefied gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/04—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by other properties of handled fluid before transfer
    • F17C2223/042—Localisation of the removal point
    • F17C2223/043—Localisation of the removal point in the gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/04—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by other properties of handled fluid before transfer
    • F17C2223/042—Localisation of the removal point
    • F17C2223/046—Localisation of the removal point in the liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2225/00—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel
    • F17C2225/01—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel characterised by the phase
    • F17C2225/0107—Single phase
    • F17C2225/0123—Single phase gaseous, e.g. CNG, GNC
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/03—Heat exchange with the fluid
    • F17C2227/0302—Heat exchange with the fluid by heating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/03—Heat exchange with the fluid
    • F17C2227/0367—Localisation of heat exchange
    • F17C2227/0388—Localisation of heat exchange separate
    • F17C2227/0393—Localisation of heat exchange separate using a vaporiser
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/03—Control means
    • F17C2250/032—Control means using computers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/03—Control means
    • F17C2250/034—Control means using wireless transmissions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/04—Indicating or measuring of parameters as input values
    • F17C2250/0404—Parameters indicated or measured
    • F17C2250/0408—Level of content in the vessel
    • F17C2250/0417—Level of content in the vessel with electrical means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/04—Indicating or measuring of parameters as input values
    • F17C2250/0404—Parameters indicated or measured
    • F17C2250/043—Pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/04—Indicating or measuring of parameters as input values
    • F17C2250/0404—Parameters indicated or measured
    • F17C2250/0439—Temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/04—Indicating or measuring of parameters as input values
    • F17C2250/0486—Indicating or measuring characterised by the location
    • F17C2250/0491—Parameters measured at or inside the vessel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/06—Controlling or regulating of parameters as output values
    • F17C2250/0605—Parameters
    • F17C2250/0615—Mass or weight of the content of the vessel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/06—Controlling or regulating of parameters as output values
    • F17C2250/0605—Parameters
    • F17C2250/0626—Pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/06—Controlling or regulating of parameters as output values
    • F17C2250/0605—Parameters
    • F17C2250/0636—Flow or movement of content
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/06—Controlling or regulating of parameters as output values
    • F17C2250/0689—Methods for controlling or regulating
    • F17C2250/0694—Methods for controlling or regulating with calculations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2260/00—Purposes of gas storage and gas handling
    • F17C2260/02—Improving properties related to fluid or fluid transfer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2265/00—Effects achieved by gas storage or gas handling
    • F17C2265/03—Treating the boil-off
    • F17C2265/032—Treating the boil-off by recovery
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2265/00—Effects achieved by gas storage or gas handling
    • F17C2265/06—Fluid distribution
    • F17C2265/066—Fluid distribution for feeding engines for propulsion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0102—Applications for fluid transport or storage on or in the water
    • F17C2270/0105—Ships
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0165—Applications for fluid transport or storage on the road
    • F17C2270/0168—Applications for fluid transport or storage on the road by vehicles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0165—Applications for fluid transport or storage on the road
    • F17C2270/0168—Applications for fluid transport or storage on the road by vehicles
    • F17C2270/0171—Trucks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0165—Applications for fluid transport or storage on the road
    • F17C2270/0168—Applications for fluid transport or storage on the road by vehicles
    • F17C2270/0173—Railways
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0165—Applications for fluid transport or storage on the road
    • F17C2270/0168—Applications for fluid transport or storage on the road by vehicles
    • F17C2270/0176—Buses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C9/00—Methods or apparatus for discharging liquefied or solidified gases from vessels not under pressure
    • F17C9/02—Methods or apparatus for discharging liquefied or solidified gases from vessels not under pressure with change of state, e.g. vaporisation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Combustion & Propulsion (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

The invention relates to a method for determining the functionality of a pressure regulator (140). The pressure regulator (140) alternating between a first state, where fuel gas in liquid phase (111 ) is drawn from the gas storage device (110), and a second state, where fuel gas in gaseous phase (112) is drawn from the gas storage device (110). The method comprising: determining (s101 ), at a first time, a first thermodynamic state of the gas storage device (110); determining (s102), at a second time, a second thermodynamic state of the gas storage device (110); calculating (s103) an expected thermodynamic state of the gas storage device (110) for said second time, based on the setting of the pressure regulator (140); the first thermodynamic state and the mass of the fuel gas outtake between the first time and the second time; and determining (s104) the functionality of the pressure regulator (140) by comparing the expected thermodynamic state with the determined second thermodynamic state.

Description

A method for determining the functionality of a pressure regulator and a liquefied gas fuel system TECHNICAL FIELD The present invention relates to a method for determining the functionality of a pressure regulator associated with a liquefied gas fuel system, a liquefied gas fuel system, a vehicle, a computer program and a computer-readable medium.
BACKGROUND Today, alternative fuels, such as natural gas and biogas, are being introduced for propelling vehicles. The fuel gas is typically stored in gas tanks and there are at least two main principles when storing the fuel gas. According to one principle, the fuel gas is stored under high pressure in the gas tank. Compressed natural gas, CNG, is for example stored according to this principle. By compressing the gas heavily a higher density is achieved. According to another principle, the gas is stored at least partly in its liquid phase. This is the case for liquefied natural gas, LNG. By transforming the gas into its liquid phase, a further increase in density is achieved. However, for transforming the gas into its liquid phase usually quite low temperatures are needed. The temperatures which are needed to keep the gas in its liquid phase are often below -110 degrees Celsius.
LNG is a common two-phase fuel gas and is stored in a liquid phase and a gaseous phase in a gas tank. Over time, if the gas engine is not operating, the temperature in the gas tank will increase and LNG in the liquid phase will evaporate into the gaseous phase. The pressure inside the gas tank will thereby increase. If the pressure becomes too high, the gas tank may be damaged. At least one pressure relief valve is therefore typically arranged at the gas tank. The at least one pressure relief valve is arranged to open when the pressure in the gas tank exceeds a certain pressure value, and thereby evacuate fuel gas to the atmosphere. Evacuated fuel gas is of course wasted fuel gas and it is therefore desired to control the pressure in the gas tank, such that the pressure relief valve does not have to evacuate fuel gas.
A pressure regulator called economiser is typically arranged to control the pressure in the gas tank, by regulating whether fuel gas in the liquid phase or the gaseous phase is taken out from the gas tank to be supplied to the gas engine. The economiser may be arranged to alternate between a first state, in which fuel gas in the liquid state is drawn from the gas tank, and a second state, in which fuel gas in the gaseous phase is drawn from the gas tank. The economiser may be arranged to ensure that fuel gas in the gaseous phase is drawn from the gas tank when the pressure in the gas tank exceeds a certain threshold value. Should the economiser for some reason break or should the function of the economiser deteriorate, there is a risk that the pressure in the gas tank becomes too high or too low. It would thus be advantageous to be able to monitor the functionality of the economiser.
SUMMARY OF THE INVENTION An object of the present invention is to achieve a new and advantageous method for determining the functionality of a pressure regulator associated with a liquefied gas fuel system.
Another object of the present invention is to achieve an alternative method for determining the functionality of a pressure regulator associated with a liquefied gas fuel system.
A further object of the invention is to achieve a new and advantageous liquefied gas fuel system, a vehicle, a computer program and a computer-readable medium.
The herein mentioned objects are achieved by a method for determining the functionality of a pressure regulator associated with a liquefied gas fuel system, a liquefied gas fuel system, a computer program and a computer-readable medium according to the appended claims.
Hence, according to an aspect of the invention a method for determining the functionality of a pressure regulator associated with a liquefied gas fuel system is provided. The liquefied gas fuel system comprising at least one gas storage device storing liquefied fuel gas and a pressure regulator arranged downstream of the gas storage device, wherein the pressure regulator is set to alternate between a first state and a second state depending on the pressure in the gas storage device, wherein the pressure regulator in the first state ensures that fuel gas in liquid phase is drawn from the gas storage device, and in the second state ensures that fuel gas in gaseous phase is drawn from the gas storage device. The method comprising the steps of: - determining, at a first time, a first thermodynamic state of the gas storage device; - determining, at a second time, a second thermodynamic state of the gas storage device; - calculating an expected thermodynamic state of the gas storage device for said second time, based on the setting of the pressure regulator; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device between the first time and the second time; and - determining the functionality of the pressure regulator by comparing the expected thermodynamic state with the determined second thermodynamic state.
Determining the functionality of the pressure regulator may also be referred to as diagnosing the pressure regulator. The herein mentioned method may thus be referred to as a method for diagnosing a pressure regulator associated with a liquefied gas fuel system.
The pressure in the gas storage device may be controlled by alternating between taking out fuel gas in liquid phase and taking out fuel gas in gaseous phase from the gas storage device by means of the pressure regulator. Since the fuel gas in its liquid phase is considerably denser than in its gaseous phase, the pressure in the gas storage device will drop more quickly when fuel gas in the gaseous phase is taken out from the gas storage device. For safety reasons, the pressure regulator is thus suitably set to ensure that fuel gas in the gaseous phase is taken out from the gas storage device when the pressure in the gas storage device becomes too high. The pressure regulator may be set to switch from the first state to the second state when the pressure in the gas storage device exceeds a certain threshold value. The setting of the pressure regulator comprises the threshold value at which the pressure regulator switches to the second state. The setting of the pressure regulator, and thus the threshold value, is suitably known.
The thermodynamic state of the gas storage device may be referred to as the condition of the gas storage device at a specific time. The thermodynamic state and thus the condition of the gas storage device may be described by thermodynamic variables, such as pressure, temperature and/or volume. When a sufficiently large number of variables are known, the value of all other variables can be uniquely determined by using the equation of state. The equation of state may thus be used to provide a mathematical relationship between two or more variables, such as mass, enthalpy, entropy, pressure, temperature, volume, density etc. Thus, by using the equation of state, an expected thermodynamic state can be calculated based on a number of known variables. It is suitably assumed that the composition and the volume of the liquefied fuel gas are known. The method according to the invention comprises to calculate an expected thermodynamic state of the gas storage device, assuming that the pressure regulator functions according to its setting, and to compare the calculated state with a determined state and thereby determine if the pressure regulator functions properly or not. Normally some sort of electrical component would be used to determine the functionality of the pressure regulator. However, the low temperature and the high mass flow rate in association with the pressure regulator in a liquefied gas fuel system make this a considerable challenge. Thus, by determining the thermodynamic state of the gas storage device at two different occasions, as well as the fuel gas consumed during the time period between theses occasions, a calculated value can be compared to a measured value and the pressure regulator is thereby diagnosed.
The method according to the invention may comprise to: determine, at a first time, first values of at least two predetermined thermodynamic variables of the gas storage device; determine, at a second time, second values of the predetermined thermodynamic variables; calculate an expected value of one of the predetermined thermodynamic variables for said second time; and determine the functionality of the pressure regulator by comparing the expected value with the determined value for that thermodynamic variable. Calculating an expected value of a thermodynamic variable may comprise to input determined first values of at least two thermodynamic variables and the fuel gas consumed between the first time and the second time, into a model based on the equation of state. The known composition and volume of the liquefied fuel gas is suitably also input to the model. The expected value achieved by means of the model is then compared with measured values and the functionality of the pressure regulator can thereby be diagnosed.
The liquefied fuel gas, which is stored in the at least one gas storage device, may be liquefied natural gas, LNG. LNG is an important fuel gas and the method is especially suitable for that gas. It is commonly known that a liquefied fuel gas is stored in a liquid phase and a gaseous phase in a gas storage device. The liquefied fuel gas is suitably stored under pressure in the gas storage device and the temperature is suitably between -160 to -110 degrees Celsius.
According to an embodiment of the invention determining a first thermodynamic state of the gas storage device comprises to determine a first pressure and a first fuel gas level. The first fuel gas level is suitably determined by means of the level sensor in the gas storage device and the first pressure in the gas storage device may be determined by means of a pressure sensor arranged in association with the gas storage device. The amount of fuel gas in the gas storage device largely depends on the level of fuel gas in the liquid phase. The level sensor may therefore be adapted to provide a fuel gas level indicating the level of fuel gas in its liquid phase. The fuel gas level provided by the level sensor may indicate the percentage of the total volume in the gas storage device that consists of fuel gas in the liquid phase. Determining a first thermodynamic state of the gas storage device may further comprise to determine the mass of fuel gas in the gaseous phase and the mass of fuel gas in the liquid phase at the first time, based on the first pressure and the first fuel gas level. By determining the pressure and the first fuel gas level in the gas storage device at the first time, the equation of state can be used to determine how much of the fuel gas that is in liquid phase and how much that is in gaseous phase. The volume enclosed by the gas storage device is known, whereby the determined first fuel gas level can be used to determine the volume of fuel gas in liquid phase and the volume of fuel gas in gaseous phase. By knowing the pressure in the gas storage device and the volume of fuel gas in the respective phase, the equation of state can be used to calculate the mass of fuel gas in gaseous phase and the mass of fuel gas in liquid phase. The equation of state may also be used to determine the density of fuel gas in gaseous phase and the density of fuel gas in liquid phase.
According to an embodiment of the invention the determination of the mass of fuel gas in the gaseous phase and the mass of fuel gas in the liquid phase is further based on the temperature in the gas storage device. The step of determining a first thermodynamic state of the gas storage device may thus comprise to determine a first temperature in the gas storage device. The first temperature may be determined by means of a temperature sensor arranged in association with the gas storage device. Alternatively, the determination of the mass of fuel gas in the gaseous phase and the mass of fuel gas in the liquid phase may be based on the assumption that the fuel gas is thermodynamically saturated. When the fuel gas is considered to be thermodynamically saturated the fuel gas in gaseous phase and liquid phase can exist together at a given temperature and pressure. Thus, at saturated conditions the pressure and temperature of the fuel gas fall on a known saturation curve. By assuming saturation, the temperature in the gas storage device does not have to be measured but can be determined from the saturation curve by knowing the pressure. The mass of the fuel gas in gaseous phase respectively in liquid phase can thereby be determined through the equation of state by knowing the variables pressure, volume and temperature.
Thus, the step of determining a first thermodynamic state of the gas storage device may comprise to determine a first fuel gas level and a first pressure and/or a first temperature. In the case where saturation is assumed a first pressure or a first temperature is suitably determined together with a first fuel gas level. The saturation curve will then give the other variable and the mass/density of the fuel gas in gaseous and in liquid phase can thereby be determined. However, in the case where saturation is not assumed, a first pressure and a first temperature is suitably determined together with a first fuel gas level. The mass/density of the fuel gas in gaseous and in liquid phase can thereby be determined. The step of determining a first thermodynamic state of the gas storage device is suitably also based on the known composition and volume of the liquefied fuel gas.
Determining a second thermodynamic state of the gas storage device suitably comprises to determine a second pressure and a second fuel gas level. The second fuel gas level may be determined by means of the level sensor and the second pressure in the gas storage device may be determined by means of the pressure sensor arranged in association with the gas storage device. Determining a second thermodynamic state of the gas storage device may comprise to determine a second fuel gas level and a second pressure and/or a second temperature. If saturation is assumed a second pressure or a second temperature may be determined together with a second fuel gas level. The saturation curve will then give the other variable. However, if saturation is not assumed a second pressure and a second temperature is suitably determined together with a second fuel gas level. The step of determining a second thermodynamic state of the gas storage device is suitably also based on the known composition and volume of the liquefied fuel gas.
According to an embodiment of the invention calculating an expected thermodynamic state of the gas storage device comprises to determine the distribution of fuel gas outtake in liquid phase respectively gaseous phase between the first time and the second time. Whether fuel gas in gaseous phase or in liquid phase is drawn from the gas storage device may depend on the setting of the pressure regulator. The setting of the pressure regulator comprises the threshold value at which the pressure regulator switches to the second state and draws fuel gas in the gaseous phase from the gas storage device. By knowing the pressure in the gas storage device and the setting of the pressure regulator it can be determined in which state the pressure regulator should be when it is functioning properly. The expected thermodynamic state is calculated based on the assumption that the pressure regulator is functioning according to its setting. Thus, based on the setting of the pressure regulator and based on the first pressure in the gas storage device at the first time it can be determined how the fuel gas outtake should have varied between the liquid phase and the gaseous phase during the specified time period. The fuel gas outtake, i.e. the amount of fuel gas consumed by the gas engine during the time period, is known. It may thus be determined how much of the fuel gas outtake that was in liquid phase and how much that was in gaseous phase. The mass of fuel gas in liquid phase and the mass of fuel gas in gaseous phase that was taken out from the gas storage device between the first time and the second time may thereby be determined. Based on the determined first thermodynamic state and specifically based on the mass of fuel gas in liquid phase and the mass of fuel gas in gaseous phase at the first time, and based on the determined distribution of fuel gas outtake an expected mass of fuel gas in liquid phase and an expected mass of fuel gas in gaseous phase at said second time can be calculated. The expected thermodynamic state of the gas storage device may be calculated based on the assumption of saturation.
According to an embodiment of the invention calculating an expected thermodynamic state of the gas storage device comprises to calculate an expected pressure for said second time or to calculate an expected fuel gas level for said second time. Thus, an expected pressure or an expected fuel gas level may be calculated based on the setting of the pressure regulator; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device between the first time and the second time. The expected pressure or fuel gas level may be calculated based on the setting of the pressure regulator; the first pressure, the mass of fuel gas in gaseous phase and in liquid phase at the first time and based on the mass of the fuel gas outtake from the gas storage device between the first time and the second time. An expected pressure for said second time may be calculated also based on the determined second fuel gas level. An expected fuel gas level for said second time may be calculated also based on the determined second pressure. As mentioned above, the distribution of fuel gas outtake in liquid phase respectively gaseous phase between the first time and the second time is suitably determined, which enables calculation of expected masses of fuel gas in the respective phase. Thus, the expected masses of fuel gas in the respective phase are known, the pressure or the fuel gas level at the second time is known, and an expected pressure or fuel gas level can thereby be calculated with the equation of state. The functionality of the pressure regulator may thereby comprise to compare the expected pressure with the determined second pressure or by comparing the expected fuel gas level with the determined second fuel gas level. If the expected pressure or fuel gas level differs from the determined second pressure or second fuel gas level with more than a predetermined value, the pressure regulator is considered to malfunction.
The method according to the invention may thus comprise the steps of: determining, at a first time, a first pressure and a first fuel gas level in the gas storage device; determining, at a second time, a second pressure and a second fuel gas level in the gas storage device; calculating an expected pressure for said second time based on: the setting of the pressure regulator; the first pressure and the first fuel gas level; the fuel gas outtake from the gas storage device between the first time and the second time; and the second fuel gas level; and determining the functionality of the pressure regulator by comparing the expected pressure with the determined second pressure.
The method according to the invention may alternatively comprise the steps of: determining, at a first time, a first pressure and a first fuel gas level in the gas storage device; determining, at a second time, a second pressure and a second fuel gas level in the gas storage device; calculating an expected fuel gas level for said second time based on: the setting of the pressure regulator; the first pressure and the first fuel gas level; the fuel gas outtake from the gas storage device between the first time and the second time; and the second pressure; and determining the functionality of the pressure regulator by comparing the expected fuel gas level with the determined second fuel gas level.
The diagnosed pressure regulator may be part of a liquefied gas fuel system for a gas engine of a vehicle. The method according to the invention may thus suitably be used for diagnosing a pressure regulator of a vehicle. The present invention may, however, also be used in connection with any other platform than vehicles, as long as this platform comprises a gas engine.
The method according to the present invention may be performed by a control unit of a liquefied gas fuel system. The control unit may be an engine control unit or a separate control unit. The control unit may comprise a plurality of control units.
According to an aspect of the invention a liquefied gas fuel system is provided. The system comprises at least one gas storage device storing liquefied fuel gas and a pressure regulator arranged downstream of the gas storage device, wherein the pressure regulator is set to alternate between a first state and a second state depending on the pressure in the gas storage device, wherein the pressure regulator in the first state ensures that fuel gas in liquid phase is drawn from the gas storage device, and in the second state ensures that fuel gas in gaseous phase is drawn from the gas storage device. The system further comprises a control unit comprising: means for determining, at a first time, a first thermodynamic state of the gas storage device; means for determining, at a second time, a second thermodynamic state of the gas storage device; means for calculating an expected thermodynamic state of the gas storage device for said second time, based on the setting of the pressure regulator; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device between the first time and the second time; and means for determining the functionality of the pressure regulator by comparing the expected thermodynamic state with the determined second thermodynamics state.
The means for determining a first thermodynamic state of the gas storage device; the means for determining a second thermodynamic state of the gas storage device; the means for calculating an expected thermodynamic state of the gas storage device for said second time; and the means for determining the functionality of the pressure regulator may e.g. be different software modules/portions in the control unit, program code or similar.
The liquefied fuel gas is suitably stored under pressure in the gas storage device and the temperature is suitably between -160 to -110 degrees Celsius. The temperature in the gas storage device will increase over time and fuel gas in the liquid phase will evaporate into the gaseous phase. The pressure inside the gas storage device will thereby increase. If the pressure becomes too high, the gas storage device may be damaged. The liquefied gas fuel system may therefore comprise at least one pressure relief valve. The at least one pressure relief valve may be arranged to open when the pressure in the gas storage device exceeds a certain pressure value, and thereby evacuate fuel gas to the atmosphere. The threshold value at which the pressure regulator is arranged to switch to the second state is suitably lower than the pressure value at which the at least one pressure relief valve is arranged to open and evacuate fuel gas.
The liquefied gas fuel system may further comprise a so called pressure build up device, adapted to add energy to the system in order to increase the pressure in the gas storage device. Energy is then transferred from outgoing heated fuel gas in gaseous phase to the fuel gas in liquid phase in the gas storage device. Some of the fuel gas in liquid phase may thereby evaporate to gaseous phase. Such a pressure build up device is typically arranged to only transfer energy at specific pressures in the gas storage device. The method according to the invention may thus comprise to calculate an expected thermodynamic state based on the state of the pressure build up device. By knowing the pressure in the gas storage device, the state of the pressure build up device can be determined and fuel gas in liquid phase evaporating to gaseous phase can thereby be considered when calculating an expected thermodynamic state.
It will be appreciated that all the embodiments described for the method aspect of the invention are also applicable to the liquefied gas fuel system aspect of the invention. That is, the control unit of the liquefied gas fuel system may be configured to perform any one of the steps of the method according to various embodiments described herein.
Further objects, advantages and novel features of the present invention will become apparent to one skilled in the art from the following details, and also by putting the invention into practice. Whereas embodiments of the invention are described below, it should be noted that it is not restricted to the specific details described. Specialists having access to the teachings herein will recognise further applications, modifications and incorporations within other fields, which are within the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and further objects and advantages of it, the detailed description set out below should be read together with the accompanying drawings, in which the same reference notations denote similar items in the various diagrams, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment of the invention; Figure 2 schematically illustrates a liquefied gas fuel system according to an embodiment of the invention; Figure 3 illustrates a flow chart for a method for determining the functionality of a pressure regulator according to an embodiment of the invention; and Figure 4 schematically illustrates a control unit or computer according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a side view of a vehicle 1 according to an embodiment of the invention. The vehicle 1 comprises a propulsion unit 2. The propulsion unit 2 is suitably a gas engine. The vehicle 1 may further comprise a liquefied gas fuel system 10 for supplying liquefied fuel gas to the gas engine 2. Such a fuel system 10 is described in Figure 2. The vehicle 1 can be any kind of vehicle comprising a gas engine. Examples of vehicles comprising a gas engine are trucks, busses, boats, passenger cars, construction vehicles, and locomotives. The present invention can also be used in connection with any other platform than vehicles, as long as this platform comprises a gas engine. One example is a power plant with a gas engine.
In the following, the gas fuel system 10 will be described as it can be embodied when using it in a vehicle 1. As a consequence, not all components in the description are necessary. They are, however, added in the description for showing a preferred embodiment of the present disclosure.
The term “link” refers herein to a communication link which may be a physical connection such as an opto-electronic communication line, or a non-physical connection such as a wireless connection, e.g. a radio link or microwave link.
The term “passage” refers herein to a passage suitable for transporting fuel gas. The passage can, for example, be a pipe, a hose, a tube, a channel, or the like. The passage can be rigid or flexible.
Figure 2 schematically shows a liquefied gas fuel system 10 according to an embodiment of the invention. The system 10 comprises at least one gas storage device 110 storing liquefied fuel gas and a pressure regulator 140 arranged downstream of the gas storage device 110. The pressure regulator 140 is set to alternate between a first state and a second state depending on the pressure in the gas storage device 110, wherein the pressure regulator 140 in the first state is adapted to ensure that fuel gas in liquid phase 111 is drawn from the gas storage device 110, and in the second state is adapted to ensure that fuel gas in gaseous phase 112 is drawn from the gas storage device 110.
The fuel gas which is stored in the gas storage device 110 may be liquefied natural gas, LNG. LNG is a common two-phase gas which can be used for propelling vehicles. LNG is usually stored well below -100 degree Celsius in the gas storage device 110. The gas storage device 110 may be a cryogenic gas tank.
The system 10 may comprise a level sensor 100 arranged to determine the fuel gas level L in the gas storage device 110. The amount of fuel gas in the gas storage device 110 largely depends on the level of fuel gas in the liquid phase 111. The level sensor 100 may therefore be adapted to provide a fuel gas level L indicating the level of fuel gas in liquid phase 111. The level sensor 100 may be configured to measure the capacitive differences between the fuel gas in liquid phase 111 and the fuel gas in gaseous phase 112 and thereby determine the fuel gas level L. The level sensor 100 is suitably arranged centrally in the gas storage device 110.
The system 10 is suitably adapted to supply fuel gas to a gas engine as disclosed in Figure 1. The gas engine is, however, not illustrated in this figure. The gas fuel system 10 comprises at least one passage 161 , 162, 163, 164 for transporting the fuel gas from the gas storage device 110 to the gas engine. Said at least one passage 161 , 162, 163, 164 may comprise a first passage section 161 , arranged to transport fuel gas in its gaseous phase 112 from the gas storage device 110. Said at least one passage 161 , 162, 163, 164 may comprise a second passage section 162, arranged to transport fuel gas in its liquid phase 111 from the gas storage device 110.
The pressure regulator 140 is suitably arranged in fluid communication with the first passage section 161 and the second passage section 162. In this embodiment, the pressure regulator 140 is arranged to alternate between a first state, where fuel gas in liquid phase 111 is drawn from the gas storage device 110 via the second passage section 162, and a second state, where fuel gas in gaseous phase 112 is drawn from the gas storage device 110 via the first passage section 161. The pressure regulator 140 is suitably set to switch from the first state to the second state when the pressure in the gas storage device 110 exceeds a threshold value. The threshold value is suitably known. The threshold value may be around 10 bar. Said threshold value may relate to the pressure of the fuel gas in gaseous phase 112. The pressure regulator 140 may be arranged to perform the switching between the first state and the second state purely mechanically. The pressure regulator 140 may alternatively be electronically controlled. The pressure regulator 140 may be a so-called economiser.
The system 10 may comprise sensor means 120 arranged in association with the gas storage device 110. The sensor means 120 may comprise a pressure sensor arranged to determine a pressure in the gas storage device 110. Said pressure may be a pressure of the fuel gas in its gaseous phase 112. Said pressure may be a pressure of the fuel gas in its liquid phase 111. The sensor means 120 may be arranged at least partly inside the gas storage device 110. In an alternative embodiment a pressure sensor could be arranged in the first passage section 161 and/or the second passage section 162. Since these passage sections 161 , 162 are connected to the gas storage device 110 the pressure inside the passage section 161 , 162 either corresponds to the pressure in the gas storage device 110, or at least can be converted to a pressure in the gas storage device 110. The sensor means 120 may also comprise a temperature sensor arranged for determining the temperature in the gas storage device 110.
The system 10 may further comprise a heat exchanger device 150 arranged downstream of the pressure regulator 140. Said at least one passage 161 , 162, 163, 164 may comprise a third passage section 163. Said third passage section 163 may be arranged to transport fuel gas from the pressure regulator 140 to the heat exchange device 150. The heat exchange device 150 may use cooling water from the gas engine to heat the fuel gas coming from the pressure regulator 140. This assures that fuel gas drawn from the liquid phase 111 in the gas storage device 110 will be converted into its gaseous phase 112 before reaching the gas engine.
The system 10 may further comprise a gas regulator system (not shown) arranged downstream of the heat exchanger device 150. The gas engine has a preferred input gas pressure. This preferred input gas pressure may be supplied by the gas regulator system. In one example, the preferred input gas pressure is around 7 bar. The at least one passage 161 , 162, 163, 164 may comprise a fourth passage section 164. Said fourth passage section 164 may be arranged to transport fuel gas from the heat exchange system 150 or the gas regulator system to the gas engine.
The system 10 may also comprise a so called pressure build up device (not shown), arranged to add energy to the system 10 in order to maintain a certain pressure. A pressure build up device may be arranged to transfer energy from outgoing heated fuel gas in gaseous phase 112 to the fuel gas in liquid phase 111 in the gas storage device 110, to increase the pressure in the gas storage device 110.
The liquefied gas fuel system 10 may further comprise a control unit 200. The control unit 200 is arranged in communication with the level sensor 100; the sensor means 120; the pressure regulator 140 and the heat exchange system 150. The control unit 200 may be arranged to control operation of said level sensor 100. The control unit 200 may be arranged for communication with said level sensor 100 via a link L100. The control unit 200 may be arranged to receive information from said level sensor 100. The control unit 200 may be arranged to control operation of said sensor means 120. The control unit 200 may be arranged for communication with said sensor means 120 via a link L120. The control unit 200 may be arranged to receive information from said sensor means 120. In case the gas fuel system 10 comprises several pressure sensors and/or temperature sensors, said control unit 200 may be arranged for communication with each of these several sensors. The control unit 200 may then be arranged to receive information from said several sensors.
In one embodiment, the control unit 200 is arranged to control operation of the pressure regulator 140. The control unit 200 may thus be arranged for communication with said pressure regulator 140 via a link L140. The control unit 200 may be arranged to receive information from said pressure regulator 140 via the link L140. In one example, the control unit 200 is arranged to control the pressure regulator 140 to switch from a first state to a second state, or vice versa.
The control unit 200 may be arranged to control operation of the heat exchange system 150. The control unit 200 may be arranged for communication with said heat exchange system 150 via a link L150. The control unit 200 may be arranged to receive information from said heat exchange system 150 via the link L150.
The control unit 200 suitably comprises means for diagnosing the pressure regulator 140. The control unit 200 may comprise means for determining, at a first time, a first thermodynamic state of the gas storage device 110; means for determining, at a second time, a second thermodynamic state of the gas storage device 100; means for calculating an expected thermodynamic state of the gas storage device 110 for said second time, based on the setting of the pressure regulator 140; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device between the first time and the second time; and means for determining the functionality of the pressure regulator 140 by comparing the expected thermodynamic state with the determined second thermodynamic state. These means may be different modules/programs in the control unit 200 or it may be models/algorithms stored in the control unit 200.
A computer 205 may be arranged for communication with the control unit 200 via a link L205 and may be detachably connected to it. The computer 205 may be adapted to conduct the innovative method steps according to the invention. The computer 205 may be used to cross-load software to the control unit 200, particularly software for conducting the innovative method. The computer 205 may alternatively be arranged for communication with the control unit 200 via an internal network on board the vehicle. The innovative method as described in Figure 3 may be conducted by the control unit 200 or the computer 205, or by both of them.
Figure 3 illustrates a flow chart for a method for determining the functionality of a pressure regulator 140 associated with a liquefied gas fuel system 10 according to an embodiment of the invention. The liquefied gas fuel system 10 is suitably configured as disclosed in Figure 2 and thus comprises at least one gas storage device 110 storing liquefied fuel gas and a pressure regulator 140 arranged downstream of the gas storage device 110. The pressure regulator 140 is set to alternate between a first state and a second state depending on the pressure in the gas storage device 110, wherein the pressure regulator 140 in the first state ensures that fuel gas in liquid phase 111 is drawn from the gas storage device 110, and in the second state ensures that fuel gas in gaseous phase 112 is drawn from the gas storage device 110. The method comprises the steps of: determining s101 , at a first time, a first thermodynamic state of the gas storage device 110; determining s102, at a second time, a second thermodynamic state of the gas storage device 110; calculating s103 an expected thermodynamic state of the gas storage device 110 for said second time, based on the setting of the pressure regulator 140; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device 110 between the first time and the second time; and determining s104 the functionality of the pressure regulator 140 by comparing the expected thermodynamic state with the determined second thermodynamic state. The pressure regulator 140 is thus diagnosed by calculating an expected thermodynamic state of the gas storage device 110 and comparing it with a determined thermodynamic state.
The method is suitably performed by a control unit 200 or computer 205 as disclosed in Figure 2. The method may be performed continuously during operation of a gas engine or it may be performed according to a predetermined interval.
The thermodynamic state of the gas storage device 110 may be referred to as the condition of the gas storage device 110 at a specific time. The thermodynamic state and thus the condition of the gas storage device 110 may be described by thermodynamic variables, such as pressure, temperature and/or volume. When a sufficiently large number of variables are known, the value of all other variables can be uniquely determined by using the equation of state. The equation of state may thus be used to provide a mathematical relationship between two or more state variables, such as mass, enthalpy, entropy, pressure, temperature, volume, density etc. It is assumed that the composition and the volume of the fuel gas are known. Thus, by using the equation of state, an expected thermodynamic state can be calculated based on a number of known variables. The method according to the invention comprises to calculate an expected thermodynamic state of the gas storage device 110, assuming that the pressure regulator 140 functions according to its setting, and to compare the calculated state with a determined state and thereby determine if the pressure regulator 140 functions properly or not. The step of calculating the expected thermodynamic state is suitably based on the equation of state. The equation of state relating to the gas storage device 110 is suitably stored in the control unit 200.
The step of determining s101 a first thermodynamic state of the gas storage device 110 may comprise to determine a first pressure and a first fuel gas level. The step of determining s101 a first thermodynamic state of the gas storage device 110 may comprise to determine a first fuel gas level and a first pressure and/or a first temperature. The first fuel gas level is suitably determined by means of the level sensor 100 and the first pressure in the gas storage device may be determined by means of a pressure sensor 120 arranged in association with the gas storage device 110. The first temperature may be determined by means of a temperature sensor 120 arranged in association with the gas storage device 110.
The step of determining s101 a first thermodynamic state of the gas storage device 110 may further comprise to determine the mass of fuel gas in the gaseous phase 112 and the mass of fuel gas in the liquid phase 111 at the first time, based on the first pressure and the first fuel gas level. The mass of fuel gas in gaseous phase 112 and liquid phase 111 may be determined based on the first temperature in the gas storage device 110. By determining the first fuel gas level and the first pressure and/or the first temperature in the gas storage device 110 at the first time, the equation of state can be used to determine how much of the fuel gas that is in liquid phase 111 and how much that is in gaseous phase 112. Since the total volume of the gas storage device 110 is known, the determined first fuel gas level can be used to determine the volume of fuel gas in liquid phase 111 and the volume of fuel gas in gaseous phase 112. By knowing the pressure in the gas storage device 110, the volume of fuel gas in the respective phase and the temperature in the gas storage device 110, the equation of state can be used to calculate the mass of fuel gas in gaseous phase 112 and the mass of fuel gas in liquid phase 111 at said first time.
The step of determining the mass of fuel gas in the gaseous phase 112 and the mass of fuel gas in the liquid phase 111 may be based on the assumption that the fuel gas is thermodynamically saturated. By assuming saturation, the temperature in the gas storage device 110 does not have to be measured but can be determined from the saturation curve by knowing the pressure.
The step of determining s102 a second thermodynamic state of the gas storage device 110 may comprise to determine a second fuel gas level and a second pressure and/or a second temperature. The second fuel gas level may be determined by means of the level sensor 100 and the second pressure and the second temperature in the gas storage device 110 may be determined by means of a temperature sensor 120 arranged in association with the gas storage device 110.
The step of calculating s103 an expected thermodynamic state of the gas storage device 100 may comprise to determine the distribution of fuel gas outtake in liquid phase 111 respectively gaseous phase 112 between the first time and the second time. The distribution is suitably determined based on the setting of the pressure regulator 140 and the first pressure in the gas storage device 110. Based on the setting of the pressure regulator 140 and based on the first pressure in the gas storage device 110 it can be determined how the fuel gas outtake should have varied between the liquid phase 111 and the gaseous phase 112 if the pressure regulator 140 was functioning properly. The fuel gas outtake, i.e. the amount of fuel gas consumed by the gas engine during the time period between the first time and the second time, is known. The mass of fuel gas in liquid phase 111 and the mass of fuel gas in gaseous phase 112 that was taken out from the gas storage device 110 between the first time and the second time may thereby be determined. Based on the mass of fuel gas in liquid phase 111 and the mass of fuel gas in gaseous phase 112 at the first time, and based on the determined distribution of fuel gas outtake an expected mass of fuel gas in liquid phase 111 and an expected mass of fuel gas in gaseous phase 112 at said second time can be calculated.
The step of calculating s103 an expected thermodynamic state of the gas storage device 110 may comprise to calculate an expected pressure for said second time. The expected pressure may be calculated based on the setting of the pressure regulator 140; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device 110 between the first time and the second time. The expected pressure may be calculated based on the setting of the pressure regulator 140; the first pressure, the mass of fuel gas in gaseous phase 112 and in liquid phase 111 at the first time and based on the mass of the fuel gas outtake from the gas storage device 110 between the first time and the second time. The expected pressure for said second time may be calculated based on the determined second fuel gas level.
The step of calculating s103 an expected thermodynamic state of the gas storage device 110 may comprise to calculate an expected fuel gas level for said second time. The expected fuel gas level may be calculated based on the setting of the pressure regulator 140; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device 110 between the first time and the second time. The expected fuel gas level may be calculated based on the setting of the pressure regulator 140; the first pressure, the mass of fuel gas in gaseous phase 112 and in liquid phase 111 at the first time and based on the mass of the fuel gas outtake from the gas storage device 110 between the first time and the second time. The expected fuel gas level for said second time may be calculated based on the determined second pressure.
The step of determining s104 the functionality of the pressure regulator 140 may comprise to compare the expected pressure with the determined second pressure or to compare the expected fuel gas level with the determined second fuel gas level. If the expected pressure or expected fuel gas level differs from the determined second pressure or the second fuel gas level respectively, with more than a predetermined value, the pressure regulator 140 is considered to malfunction. If it is determined that the pressure regulator 140 is malfunctioning, the method may further comprise to alert an operator, such that appropriate actions can be taken.
Figure 4 is a diagram of a version of a device 500. The control unit 200 and/or computer 205 described with reference to Figure 2 may in a version comprise the device 500. The term “link” refers herein to a communication link which may be a physical connection such as an optoelectronic communication line, or a non-physical connection such as a wireless connection, e.g. a radio link or microwave link. The device 500 comprises a non-volatile memory 520, a data processing unit 510 and a read/write memory 550. The non-volatile memory 520 has a first memory element 530 in which a computer programme, e.g. an operating system, is stored for controlling the function of the device 500. The device 500 further comprises a bus controller, a serial communication port, I/O means, an A/D converter, a time and date input and transfer unit, an event counter and an interruption controller (not depicted). The non-volatile memory 520 has also a second memory element 540.
There is provided a computer programme Pr which comprises routines for determining the functionality of a pressure regulator associated with a liquefied gas fuel system. The computer programme Pr comprises routines for determining a first thermodynamic state of the gas storage device. The computer programme Pr comprises routines for determining a first pressure and a first fuel gas level in a gas storage device, at a first time. The computer programme Pr comprises routines for determining a second thermodynamic state of the gas storage device. The computer programme Pr comprises routines for determining a second pressure and a second fuel gas level. The computer programme Pr comprises routines for calculating an expected thermodynamic state, based on the setting of the pressure regulator; the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device between the first time and the second time. The computer programme Pr comprises routines for determining the functionality of the pressure regulator by comparing the expected thermodynamic state with the determined second thermodynamic state.
The programme Pr may be stored in an executable form or in a compressed form in a memory 560 and/or in a read/write memory 550.
Where the data processing unit 510 is described as performing a certain function, it means that the data processing unit 510 effects a certain part of the programme stored in the memory 560 or a certain part of the programme stored in the read/write memory 550.
The data processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via a data bus 511. The read/write memory 550 is adapted to communicating with the data processing unit 510 via a data bus 514.
When data are received on the data port 599, they are stored temporarily in the second memory element 540. When input data received have been temporarily stored, the data processing unit 510 is prepared to effect code execution as described above.
Parts of the methods herein described may be effected by the device 500 by means of the data processing unit 510 which runs the programme stored in the memory 560 or the read/write memory 550. When the device 500 runs the programme, methods herein described are executed.
The foregoing description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to restrict the invention to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and its practical applications and hence make it possible for specialists to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims (14)

Claims
1. A method for determining the functionality of a pressure regulator (140) associated with a liquefied gas fuel system (10), the liquefied gas fuel system (10) comprising: at least one gas storage device (110) storing liquefied fuel gas; and a pressure regulator (140) arranged downstream of the gas storage device (110), wherein the pressure regulator (140) is set to alternate between a first state and a second state depending on the pressure in the gas storage device (110), wherein the pressure regulator (140) in the first state ensures that fuel gas in liquid phase (111 ) is drawn from the gas storage device (110), and in the second state ensures that fuel gas in gaseous phase (112) is drawn from the gas storage device (110), the method comprising the steps of: - determining (s101 ), at a first time, a first thermodynamic state in the gas storage device (110); - determining (s102), at a second time, a second thermodynamic state in the gas storage device (110); - calculating (s103) an expected thermodynamic state in the gas storage device (110) for said second time, based on the setting of the pressure regulator (140); the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device (110) between the first time and the second time; and - determining (s104) the functionality of the pressure regulator (140) by comparing the expected thermodynamic state with the determined second thermodynamic state.
2. The method according to claim 1 , wherein determining a first thermodynamic state of the gas storage device (110) comprises to determine a first pressure and a first fuel gas level.
3. The method according to claim 2, wherein determining a first thermodynamic state of the gas storage device (110) further comprises to determine the mass of fuel gas in the gaseous phase (112) and the mass of fuel gas in the liquid phase (111) at the first time, based on the first pressure and the first fuel gas level.
4. The method according to claim 3, wherein determining the mass of fuel gas in the gaseous phase (112) and the mass of fuel gas in the liquid phase (111 ) is based on a temperature of the fuel gas in the gas storage device (110) at the first time.
5. The method according to claim 3 or 4, wherein determining the mass of fuel gas in the gaseous phase (112) and the mass of fuel gas in the liquid phase (111) is based on the assumption that the fuel gas is thermodynamically saturated.
6. The method according to any of the preceding claims, wherein determining a second thermodynamic state of the gas storage device (110) comprises to determine a second pressure and a second fuel gas level.
7. The method according to any of the preceding claims, wherein calculating an expected thermodynamic state of the gas storage device (110) comprises to determine the distribution of fuel gas outtake in liquid phase (111) respectively gaseous phase (112) between the first time and the second time.
8. The method according to any of the preceding claims, wherein calculating an expected thermodynamic state of the gas storage device (110) comprises to calculate an expected pressure or to calculate an expected fuel gas level.
9. The method according to claim 6 and 8, wherein determining the functionality of the pressure regulator (140) comprises to compare the expected pressure with the determined second pressure or by comparing the expected fuel gas level with the determined second fuel gas level.
10. A control unit (200) for determining the functionality of a pressure regulator (140) associated with a liquefied gas fuel system (10), the liquefied gas fuel system (10) comprising: at least one gas storage device (110) storing liquefied fuel gas; and a pressure regulator (140) arranged downstream of the gas storage device (110), wherein the control unit (200) comprises means for carrying out the method according to any one of the preceding claims.
11. A computer program (Pr), wherein said computer program comprises programme code for causing a control unit (200; 500) or a computer (205; 500) connected to the control unit (200; 500) to perform the method according to any one of claims 1-9.
12. A computer-readable medium comprising instructions, which when executed by a control unit (200; 500) or a computer (205; 500) connected to the control unit (200; 500), cause the control unit (200; 500) or the computer (205; 500) to perform the method according to any one of claims 1-9.
13. A liquefied gas fuel system (10), comprising: at least one gas storage device (110) storing liquefied fuel gas; and a pressure regulator (140) arranged downstream of the gas storage device (110), wherein the pressure regulator (140) is set to alternate between a first state and a second state depending on the pressure in the gas storage device (110), wherein the pressure regulator (140) in the first state ensures that fuel gas in liquid phase (111 ) is drawn from the gas storage device (110), and in the second state ensures that fuel gas in gaseous phase (112) is drawn from the gas storage device (110), wherein the system (10) further comprises a control unit (200) comprising: - means for determining, at a first time, a first thermodynamic state of the gas storage device (110); - means for determining, at a second time, a second thermodynamic state of the gas storage device (110); - means for calculating an expected thermodynamic state of the gas storage device (110) for said second time, based on the setting of the pressure regulator (140); the first thermodynamic state and the mass of the fuel gas outtake from the gas storage device (110) between the first time and the second time; and - means for determining the functionality of the pressure regulator (140) by comparing the expected thermodynamic state with the determined second thermodynamics state.
14. A vehicle (1) comprising a liquefied gas fuel system (10) according to claim 13.
SE1651690A 2016-12-20 2016-12-20 A method for determining the functionality of a pressure regulator and a liquefied gas fuel system SE540249C2 (en)

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