WO2019235993A1 - Method and control unit for controlling a state of fuel provided to an engine - Google Patents

Method and control unit for controlling a state of fuel provided to an engine Download PDF

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Publication number
WO2019235993A1
WO2019235993A1 PCT/SE2019/050498 SE2019050498W WO2019235993A1 WO 2019235993 A1 WO2019235993 A1 WO 2019235993A1 SE 2019050498 W SE2019050498 W SE 2019050498W WO 2019235993 A1 WO2019235993 A1 WO 2019235993A1
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WO
WIPO (PCT)
Prior art keywords
fuel
engine
pressure threshold
gaseous
pressure
Prior art date
Application number
PCT/SE2019/050498
Other languages
French (fr)
Inventor
Erik Sunnegårdh
Magnus Johansson
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
Publication of WO2019235993A1 publication Critical patent/WO2019235993A1/en

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Classifications

    • 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
    • F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/0639—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
    • F02D19/0642—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
    • F02D19/0647—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]
    • 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
    • F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/0602—Control of components of the fuel supply system
    • F02D19/0605—Control of components of the fuel supply system to adjust the fuel pressure or temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
    • B60W50/0097—Predicting future conditions
    • 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
    • F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/0602—Control of components of the fuel supply system
    • F02D19/0613—Switch-over from one fuel to another
    • F02D19/0615—Switch-over from one fuel to another being initiated by automatic means, e.g. based on engine or vehicle operating conditions
    • 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
    • F02D19/06—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/08—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 pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed simultaneously using pluralities of fuels
    • F02D19/081—Adjusting the fuel composition or mixing ratio; Transitioning from one fuel to the other
    • 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
    • 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
    • F02M21/0218—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
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • 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
    • 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

Definitions

  • the present invention relates to a method for controlling a state of fuel provided from a fuel tank to an engine, as defined in the preamble of claim 1.
  • the present invention also relates to a control unit arranged for controlling a state of fuel provided from a fuel tank to an engine, as defined in the preamble of claim 15.
  • the present invention also relates to a computer program and a computer-readable medium comprising instructions for carrying out the method according to the invention .
  • Vehicles such as for example cars, buses and trucks, are driven forward by an engine torque produced by an engine in the vehicle.
  • This engine torque is provided to the driving wheels of the vehicle through a powertrain.
  • the torque may be created at least partly in a combustion engine by combustion of fuel being injected into the engine, i.e. injected into the cylinders of the engine.
  • the fuel used for the combustion in the engine may for example include liquified natural gas (LNG) .
  • LNG liquified natural gas
  • Such liquified natural gas (LNG) is often stored in at least one pressurized fuel tank. In the tank, fuel in gaseous and liquid state is stored.
  • the pressurized fuel tank includes a gaseous fuel output conduit in contact with the gaseous state fuel, and a liquid fuel output conduit in contact with the liquid state fuel.
  • liquid state fuel may be provided to the engine through the liquid fuel output conduit
  • gaseous state fuel may be provided to the engine through the gaseous fuel output
  • the pressure P gas of the gaseous state fuel is used as, or is at least related to, a drive pressure P drive utilized for pushing the fuel out from the pressurized tank, i.e. utilized for driving the fuel out through the liquid or gaseous fuel output conduits. Therefore, the pressure P gas of the gaseous state fuel has to be high enough, i.e. above a minimum gas pressure threshold P gas min/ in order to be able to push the fuel out from tank. However, in order to prevent the pressurized tank from exploding, the pressure P gas of the gaseous fuel may not be allowed to increase above a maximal gas pressure threshold P gas max/ which for example may have a value in the region of 20 bar.
  • a safety valve may be arranged for opening the valve when the gaseous pressures P gas reaches the maximal gas pressure threshold P gas max/ thereby letting gaseous state fuel pass out to the ambient air in order to reduce the gaseous pressure P gas .
  • the gaseous state fuel has a higher octane
  • the liquid state fuel includes a mixture of various hydrocarbons providing a lower octane number/rating than the evaporated lighter hydrocarbons in the gaseous state fuel result in.
  • gaseous state fuel takes up a much greater volume than liquid state fuel due to its much lower density.
  • the pressurized fuel tank should at least partly include fuel in liquid form in order to provide an acceptable reach/range for a vehicle comprising the tank and the engine.
  • the differing octane numbers/ratings for the gaseous and liquid states of the fuel may be used such that the liquid state fuel is used under some conditions and that the gaseous state fuel is used under other conditions.
  • the gaseous state fuel may be used when a higher torque is
  • a mechanical economizer has in conventional solutions been arranged to switch between supplying liquid state fuel and gaseous state fuel to the engine.
  • Such a mechanical economizer has e.g. been arranged as a mechanical switch, which is able to switch between connecting the gaseous fuel output conduit of the tank to the engine and connecting the liquid fuel output conduit to the engine.
  • P gas 12 bar.
  • the state of the fuel being provided to the engine has an influence on the pressure P gas of the gaseous fuel
  • the component individual variations may also result in an unreliable control of the state of fuel being provided to the engine. There is therefore a risk that engine knocking might occur, since the octane number/rate of the fuel provided to the engine is not reliably controlled.
  • the object is achieved by the above mentioned method for controlling a state of fuel provided from a fuel tank to an engine, the fuel tank storing fuel in gaseous and liquid state, and including at least one gaseous fuel output conduit and at least one liquid fuel output conduit according to the characterizing portion of claim 1, the method including:
  • the state of fuel and/or the mixture/ratio of states of fuel being provided to the engine may be tailored such that the torque provided by the engine is adapted to the upcoming usage of the vehicle.
  • a pressure interval Pi th - P 2 th is also adjusted.
  • This pressure interval Pi t h - P 2 th may then be intelligently utilized for matching the upcoming usage of the vehicle with a suitable state of fuel.
  • the gaseous state fuel having a higher octane number/rate, may be stored for known upcoming in situations when it is really needed, i.e. in situations when a requested engine torque T req is so high that it cannot be provided by combustion of liquid state fuel.
  • a pressure region/interval Pi t h - P 2 th between the first pressure threshold Pi t h and the second pressure threshold P 2 t h is defined, adjusted and/or used by some embodiments of the present invention.
  • This pressure region Pi t h - P2 th does not even exist for a conventional mechanical economizer, since the conventional mechanical economizer switches only based on the pressure.
  • the pressure region Pi t h - P 2 th created by the embodiments of the present invention may be utilized for controlling the electronic controllable economizer e.g. in relation to an upcoming requested engine torque T req .
  • a more efficient usage of the gaseous state fuel, and thereby also a more powerful engine may be achieved.
  • the present invention facilitates a reliable and
  • controllable electronic economizer which enables that higher torques may be provided by the engine when needed, since more gaseous state fuel (having higher octane number/rate) will be available for being
  • the adjusting of one or more of the first pressure threshold Pi th and the second pressure threshold P 2 th is performed such that an amount of fuel in the gaseous state needed for the engine to reach the at least one upcoming operating point is
  • the information related to the upcoming usage includes one or more of :
  • the determination of the at least one upcoming operating point for the engine may be based on one or more of a large number of different information, a reliable and accurate determination can be made in any situation.
  • the upcoming usage includes one or more of:
  • N a number of breaks and/or stops N stop greater than a number threshold, fb toP ⁇ b/ toP th ⁇
  • N a number of breaks and/or stops N stop smaller than a number threshold, fb toP ⁇ b/ toP th ⁇
  • the determination of the at least one upcoming operating point for the engine may be reliably and accurately determined .
  • the information related to the road section ahead of the vehicle includes one or more of:
  • the determination of the at least one upcoming operating point for the engine may be reliably and accurately determined .
  • the information related to the road section ahead of the vehicle is based on one or more of:
  • the controlling of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is performed such that only the fuel in the gaseous state is provided to the engine if a gaseous pressure P gas of the gaseous state fuel is greater than the second pressure threshold P 2 th! P gas > P 2 th ⁇
  • the controlling of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is performed such that only the fuel in the liquid state is provided to the engine if a gaseous pressure P gas of the gaseous state fuel is smaller than the first pressure threshold Pi th/ Pgas ⁇ Pi th ⁇
  • the gas pressure P gas is high enough for being able to push the fuel out from the tank, and to the engine, i.e. that a high enough drive pressure P drive is available .
  • the controlling of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is based on a requested engine torque T req if a gaseous pressure P gas of the gaseous state fuel is greater than the first pressure threshold Pi th and smaller than the second pressure threshold P 2 th ; Pi th ⁇ P gas ⁇ P 2 th ⁇
  • an adaption of the ratios between gaseous and liquid state fuel being provided to the engine is adapted in relation to the requested torque T req .
  • the engine is then provided with the fuel it needs to provide the requested torque T req , at the same time as no valuable gaseous state fuel is unnecessarily wasted. Instead, the higher octane number/rate gaseous state fuel is saved for usage in situations when it is really needed .
  • the adjusting of the first pressure threshold Pi t h results in a value of the first pressure threshold Pi t h being greater than a minimum first pressure threshold value Pi t h min/ the minimum first pressure threshold value Pi t h min being related to a capability of the fuel tank to provide the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit.
  • the gas pressure P gas is high enough for being able to push the fuel out from the tank, and to the engine .
  • the adjusting of the second pressure threshold P 2 th results in a value of the second pressure threshold P 2 th being smaller than a maximum second pressure threshold value P 2 t h max/ the maximum second pressure threshold value P 2 t h max being related to a maximally allowed pressure P gas max for the fuel tank.
  • the second pressure threshold P 2 t h is determined in relation to the maximally allowed pressure P gas max for the tank, i.e. in relation to a safety valve release pressure.
  • the herein described second pressure threshold P 2 t h may, according to an embodiment, be equal to the maximally allowed pressure P gas max for the tank minus a safety
  • the fuel in the gaseous state has a higher octane number than the fuel in the liquid state.
  • control unit arranged for controlling a state of fuel provided from a fuel tank to an engine, the fuel tank storing fuel in gaseous and liquid state, and including at least one gaseous fuel output conduit and at least one liquid fuel output conduit, according to the characterizing portion of claim 15.
  • the control unit includes:
  • first pressure threshold Pi th indicates a pressure below which only the fuel in liquid state is provided to the engine
  • second pressure threshold P 2 th indicates a pressure above which only the fuel in the gaseous state is provided to the engine
  • the control unit has the same advantages as stated above for the method.
  • the adjusting means is arranged for performing the adjusting of one or more of the first pressure threshold Pi t h and the second pressure threshold P 2 th such that an amount of the fuel in the gaseous state needed for the engine to reach the at least one upcoming operating point is available in the tank.
  • the information related to the upcoming usage includes one or more of :
  • the upcoming usage includes one or more of:
  • N st0 p a number of breaks and/or stops N st0 p greater than a number threshold
  • the information related to the road section ahead of the vehicle includes one or more of:
  • the information related to the road section ahead of the vehicle is based on one or more of:
  • control means is arranged for performing the control of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit such that only the fuel in the gaseous state is provided to the engine if a gaseous pressure P gas of the gaseous state fuel is greater than the second pressure
  • control means is arranged for performing the control of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit such that only the fuel in the liquid state is
  • control means is arranged for performing the control of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is based on a requested engine torque T req if a gaseous pressure P gas of the gaseous state fuel is greater than the first pressure threshold P 2 th and smaller than the second pressure threshold P 2 th/ Pi th ⁇ P gas ⁇ P 2 th ⁇
  • the adjustment means is arranged for adjusting the first pressure threshold P 2 th such that it results in a value of the first pressure threshold Pi th being greater than a minimum first pressure threshold value Pi th min/ the minimum first pressure threshold value Pi th min being related to a capability of the fuel tank to provide the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit.
  • the adjustment means is arranged for adjusting the second pressure threshold P 2 th such that it results in a value of the second pressure threshold P 2 th being smaller than a maximum second pressure threshold value P 2 th max/ the maximum second pressure threshold value P 2 th max being related to a maximally allowed pressure P gas max for the fuel tank.
  • the fuel in the gaseous state has a higher octane number than the fuel in the liquid state.
  • Figure 1 is a schematic illustration of a non-limiting example of a vehicle in which the embodiments of the present invention may be implemented
  • FIG 2 is a schematic illustration of a fuel providing system, in which the embodiments of the present invention may be implemented,
  • Figures 3a-b show a conventional economizer and valves that may be used according to some embodiments of the present invention, respectively,
  • Figure 4 shows a flow chart diagram for some embodiments of the present invention
  • FIG. 5a-b schematically illustrates various pressure regions and actions made according to some embodiments of the present invention.
  • FIG. 6 is a schematic illustration of a control unit
  • Figure 1 schematically shows an example vehicle 100, such as a truck, a bus, a car, or another suitable vehicle, which will be used to explain the present invention.
  • vehicle 100 such as a truck, a bus, a car, or another suitable vehicle, which will be used to explain the present invention.
  • invention is, however, not limited to use in heavy goods vehicles as the one shown in figure 1, but may also be used in essentially any vehicle, such as lighter vehicles, e.g.
  • the vehicle 100 shown schematically in figure 1, comprises an engine 101, which may comprise a combustion engine, e.g. an engine consuming liquified natural gas (LNG) , in order to create a torque being provided for driving the vehicle, e.g. a diesel engine, or an engine working according to the Otto cycle for which an electric spark ignites a fuel and air mixture in the engine cylinders, e.g. a gasoline or ethanol engine.
  • the engine 101 may in this document comprise any device which transforms chemical energy to mechanical energy, and uses gaseous and liquid state fuel for its combustion/energy transformation. The engine then provides energy in form of a torque to the powertrain. Exhaust gases produced by the engine 101 are purified by an exhaust
  • the vehicle 100 may also include one or more other engines and/or machines, e.g. electrical machines.
  • the engine 101 may, for example, in a customary fashion, via an output shaft 102 of the engine 101, be connected with a gearbox 103, via a clutch 106 and an input shaft 109 connected to the gearbox 103.
  • An output shaft 107 from the gearbox 103 also known as a propeller shaft, drives the driving wheels 110, 111 via a final gear 108, such as e.g. a customary differential, and drive shafts 104, 105 connected with the final gear 108.
  • a fuel providing system 120 including at least one fuel tank 121, which may be pressurized, is arranged for providing the engine 101 with fuel.
  • the fuel providing system 120 is
  • a control unit 140 is in figure 1 schematically illustrated as receiving signals and/or providing control signals from and/or to the engine 101 and/or the pressurized fuel tank 121.
  • the control unit 140 may also receive and/or provide control signals to and/or from other devices in the vehicle 100.
  • control unit 140 may also comprise determining means 141, e.g. a determination unit 141, adjusting means 142, e.g. an adjustment unit 142, and control means 143, e.g. a control unit 143. These control
  • control means/units/devices 141, 142, 143 are described more in detail below, and may be divided physically into more than the herein described control means/systems/units 140, or may be arranged in less control systems/units than herein described.
  • the fuel used for the combustion in the engine 101 may for example include gaseous 125 and liquid 126 state fuel, such as e.g. states of a liquified natural gas (LNG) .
  • gaseous and liquid state fuel is stored in a fuel tank 121, which often is a pressurized fuel tank.
  • the fuel tank includes a gaseous fuel output conduit 122 in contact with the gaseous state fuel 125, and a liquid fuel output conduit 123 in contact with the liquid state fuel 126.
  • Liquid state fuel 126 may therefore be provided to the engine through the liquid fuel output conduit 123, and gaseous state fuel 125 may be provided to the engine through the gaseous fuel output conduit 122.
  • the tank 121 may include the above mentioned safety valve 124 arranged for opening the valve 124 if the gaseous pressures P gas reaches the maximal gas pressure threshold P gas max ⁇
  • the gaseous state fuel is allowed to pass out into the ambient air outside of the system/vehicle, which efficiently limits and/or reduces the gaseous pressure P gas .
  • the present invention may instead utilize an electronically controlled economizer 127
  • the electronically controlled economizer 127 includes at least one controllable valve 129 arranged in at least one of the gaseous fuel output conduit 122 and the liquid fuel output conduit 123.
  • one such electronically controllable valve 129 may be arranged at each one of the the gaseous fuel output conduit 122 and the liquid fuel output conduit 123.
  • the electronically controlled economizer 127 it is not only possible to choose to provide either gaseous or liquid state fuel to the engine (as for the conventional mechanical economizer in figure 3a) . Instead, it is possible to control the controllable at least one valve 129 of the electronically controlled economizer 127 such that essentially any combination/mixture of gaseous 125 and liquid 126 state fuel is provided to the engine. Thus, essentially any ratio of gaseous 125 and liquid 126 fuel, and therefore also any variety of possible octane numbers/rates, may hereby be provided to the engine by the control of the at least one controllable valve 129.
  • Figure 4 shows a flow chart diagram for a method 400 according to an embodiment of the present invention, i.e. a method for controlling a state of fuel provided from a fuel tank 121 to an engine 101, wherein the fuel tank 121 is storing fuel in gaseous 125 and liquid 126 state.
  • the tank 121 includes at least one gaseous fuel output conduit 122 and at least one liquid fuel output conduit 123.
  • At least one upcoming operating point for the engine 101 is determined based on one or more of information related to an upcoming usage of a vehicle 100 including the engine 101 and the fuel tank 121, and information related to a road section ahead of the vehicle 100.
  • a first pressure threshold Pi th and a second pressure threshold P2 th are adjusted based on the determined at least one upcoming operation point.
  • the first pressure threshold Pi th indicates a pressure below which only fuel in liquid state 126 is to be provided to the engine 101.
  • the second pressure threshold P 2 th indicates a pressure above which only fuel in the gaseous state 125 is to be provided to the engine 101.
  • a third step 430 of the method performed e.g. by use of a below described control unit/means 143, fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 is
  • control of the fuel flows may include control of at least one controllable valve 129 arranged in at least one of the gaseous fuel output conduit 122 and the liquid fuel output conduit 123.
  • the state of fuel and/or the mixture of states of fuel being provided to the engine may be tailored such that the torque provided by the engine is adapted to the upcoming usage of the vehicle 100.
  • a pressure interval P 2 th - P 2 th between the first pressure threshold Pi th and the second pressure threshold P 2 th is adjusted, as is illustrated in figure 5a.
  • the first pressure threshold Pi th may here be adjusted within a region defined by a minimum Pi th min and a maximum Pi_ th _max value; Pi_ th _min ⁇ Pi_th ⁇ Pi_th_max ⁇
  • the minimum first pressure threshold Pi th min may, according to an embodiment, be equal to the pressure P gas min needed for
  • the second pressure threshold P 2 th may correspondingly be adjusted within a region defined by a minimum P 2 _th_min and a maximum P 2 _th_max value; P 2-th _min ⁇ P2_th ⁇
  • the adjusted first pressure threshold value Pi th should be greater than a minimum first pressure threshold value Pi th min/ which is related to a capability of the fuel tank 121 to provide the fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123, as mentioned above.
  • the adjusted second pressure threshold value P 2 th should for example be smaller than a maximum second pressure threshold value P 2 th max/ which is related to a maximally allowed pressure P gas max for the fuel tank 121.
  • the second pressure threshold P 2 th indicates a pressure over which the gaseous state fuel in the tank 121 needs to be reduced in order to avoid the gas
  • the state of the fuel provided to the engine may be intelligently/ flexibly chosen based on one or more parameters.
  • One such example is
  • the requested torque T req which could be either a currently requested torque or a torque that will be requested during an upcoming road section, is used as a parameter.
  • the fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 may be controlled such that the fuel provided to the engine 101 includes a majority, i.e. > 50%, of the fuel in the liquid state 126 if the requested engine torque T req is lower than or equal to a maximal liquid torque T max iiq ; T req £ T max iiq .
  • the first pressure threshold Pi th may here be related to, e.g. may according to an embodiment be as low as
  • the second pressure threshold P2_th may indicate a pressure over which an amount of the gaseous state fuel 125 in the tank 121 needs to be reduced in order to avoid that the pressure P gas of the gaseous state fuel 125 reaches the
  • the control 430 of the fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 is based on a requested and/or upcoming engine torque T req .
  • mixtures/ratios are given in the following. One or more of such examples mixtures/ratios may, according to an embodiment of the present invention, be utilized as initial values for one or more of the embodiments of fuel state control described in this document.
  • 0% fuel in gaseous state 125 may be provided to the engine 101.
  • T req if the requested engine torque T req is higher than 110% of the maximal liquid torque T max n q ; T req > 1.1 * T max iiq ; then 100% fuel in gaseous state 125, i.e. 0% fuel in liquid state 126, may be provided to the engine 101.
  • a mixture of fuel in gaseous state 125 and liquid state 126 may be provided to the engine.
  • a mixture of fuel in gaseous state 125 and liquid state 126 may be provided to the engine.
  • the first pressure threshold Pi t h may, according to some embodiments, indicate a pressure below which only fuel in liquid state 126 is to be provided to the engine 101.
  • the second pressure threshold P 2 th may, according to some embodiments, indicate a pressure above which only fuel in the gaseous state 125 is to be provided to the engine 101.
  • the gas pressure P gas may e.g. be determined by usage of one or more sensors.
  • the one or more sensors may be arranged within the tank 121 and/or with the at least one gaseous state fuel output conduit 122.
  • the determined pressure P gas of the fuel in the gaseous state 125 may then be compared with the first pressure threshold Pi th ⁇ Then, if the determined pressure P gas is lower than the first pressure threshold Pi t h/ P gas ⁇ Pi th/ the fuel flows are controlled through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 such that only fuel in liquid state 125 is provided to the engine 101.
  • the determined pressure P gas of the gaseous state fuel 125 with may also be compared with the second pressure threshold P 2 th ⁇
  • control of the fuel flows may be achieved by use of one or more flow controlling arrangements, including e.g. one or more valves mounted in and/or at one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123, i.e. by the use of the electrically controlled economizer 127.
  • one or more flow controlling arrangements including e.g. one or more valves mounted in and/or at one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123, i.e. by the use of the electrically controlled economizer 127.
  • one or more of the first pressure threshold P 2 th and the second pressure threshold P 2 th are adjusted such that an amount of the fuel in the gaseous state 125 needed for the engine 101 to reach the at least one upcoming operating point is available in the tank 121 before the operating point occurs.
  • the amount of gaseous state fuel 125 being available for combustion in the engine may be adapted for the upcoming usage of the vehicle 100.
  • fuel having a higher octane number/rate i.e. gaseous state fuel
  • gaseous state fuel will to a much larger extent be available for the combustion when it is needed, e.g. when the vehicle reaches a long uphill stretch and/or should perform an acceleration.
  • a flexible control of the state of fuel being provided to the engine is achieved, which is optimized for the actual usage of the vehicle. This is a great improvement over the conventional mechanical economizer, which performed switching only based on the gas pressure P gas , often resulting in a shortage of gaseous state fuel when higher torques are requested.
  • the pressure interval Pi t h - P2 th created by the embodiments of the present invention may, as is mentioned above, be utilized for an accurate control of the state of fuel being provided to the engine.
  • a more efficient usage of the gaseous state fuel, and thereby also a more powerful engine, may be achieved within the interval. Also, the more exact and
  • the pressure interval within which such an efficient and accurate usage of the gaseous state fuel is usable may be adjusted to precisely match the future/upcoming usage of the vehicle.
  • the choice of the state of fuel to be provided to the engine may, by usage of the present invention, be coupled/matched to an upcoming usage of the vehicle, e.g. to an upcoming operational point of the vehicle and/or to an upcoming driving situation, which makes it possible to
  • the present invention facilitates a reliable and accurate control of the controllable electronic economizer such that future vehicle usage is taken into consideration.
  • the probability for the engine to be able to provide a future upcoming requested torque is greatly increased, since the amount of available gaseous state fuel will be adapted already before of the torque is requested.
  • An initial value, i.e. a value set before the herein described adjustment, for the first pressure threshold Pi th may be determined in a number of ways.
  • the first pressure threshold Pi th is determined based on at least one feature of the fuel tank 121, such as for example a size, a geometrical design and/or an output conduit design for the fuel tank 121.
  • the first pressure threshold Pi th is determined based on at least one feature of a fuel providing system 120 arranged for providing the fuel from the tank 121 to the engine 101, wherein such system features may include geometrical forms and/or
  • An initial value, i.e. a value set before the herein described adjustment, for the second pressure threshold P2 th may be determined in a number of ways. According to an embodiment, the second pressure threshold P 2 th may be determined based on a required volume of the gaseous state fuel 125 in the tank 121 and/or on the type and/or usage of the vehicle 100. For example, a bus or a garbage truck, i.e. vehicles often
  • moving/driving short distances between its stops may have a lower/smaller value for the second pressure threshold P2 th/ whereas e.g. long haulage trucks, i.e. vehicles driving/moving longer distances between its stops, may have a higher/greater value for the second pressure threshold P2 th ⁇ Further,
  • the second pressure threshold P 2 th may be determined based on at least one feature of the fuel tank 121, a level of fuel in the fuel tank 121, a relation between amounts of the gaseous state 125 and liquid state 126 fuel in the fuel tank 121, a temperature in the fuel tank 121, an ambient temperature outside the fuel tank/system/vehicle, and/or at least one requirement related to a full tank parking time period for the vehicle 100 including the fuel tank 121.
  • the threshold Pi t h and the second pressure threshold P 2 th are adjusted 420 based on the determined at least one upcoming operation point, where the at least one upcoming operating point is determined based on one or more of information related to an upcoming usage of the vehicle 100 and
  • the information related to the upcoming usage of the vehicle may, according to various embodiments, include external information, internal information, driver inputted
  • information information, information provided by at least one other vehicle, information provided by at least one external
  • the information may be provided by a driver of the vehicle, for example by a driver inputting a driving schedule, e.g. a bus line number, a delivery order number, and/or a freight/load weight.
  • a driving schedule e.g. a bus line number, a delivery order number, and/or a freight/load weight.
  • the information may also be provided by internal systems, for example a system estimating the vehicle weight.
  • vehicle weight is defined as the total weight of the used vehicle combination, including possible trailers.
  • the information may also be provided by other vehicles.
  • V2V vehicle-to- vehicle
  • the information may also be provided by one or more infrastructure devices 170 (in figure 1), e.g. including one or more servers, databases and/or registers, via so called vehicle-to-infrastructure (V2I) communication, where the information may first have been collected by other vehicles, and may have been provided to the one or more infrastructure devices 170.
  • the vehicle may thus include at least one communication device 160 (in figure 1), arranged for V2V communication, for V2I communication and/or for vehicle-to-everything (V2X) communication.
  • the upcoming usage of the vehicle may, according to an
  • the first pressure threshold Pi t h may be reduced, such that the risk for having to open he safety valve 124 is reduced, since more gaseous state fuel 125 is then consumed.
  • the first pressure threshold Pi th has to be high enough, i.e. equal to or above a minimum gas pressure threshold P gas min/ in order for the system to be able to push the fuel out from tank 121.
  • the upcoming usage of the vehicle may, according to an
  • N st0p a number of breaks and/or stops N st0p greater than a number threshold N stop th/ N stop > N stop th ⁇
  • N stop th a number threshold
  • N stop th the first and/or second pressure threshold Pi t h / P2 th may be reduced/increased.
  • the upcoming usage of the vehicle may, according to an
  • N stop also include a number of breaks and/or stops N stop smaller than a number threshold N stop th N stop ⁇ N stop th ⁇
  • N stop th For example, for long haulage vehicles, long stretches/distances are often travelled between the stops. Therefore, if a number of breaks and/or stops N stop smaller than a number threshold will come; N stop ⁇ N stop th/ then the first and/or second pressure threshold Pi t h / P2 th may be reduced/increased.
  • the upcoming usage of the vehicle may, according to an
  • the upcoming usage of the vehicle may, according to an
  • the upcoming usage of the vehicle may, according to an
  • the upcoming usage of the vehicle may, according to an
  • the at least one upcoming operating point for the engine 101 may be determined 410 at least partly based on information related to a road section ahead of the vehicle, and the adjustment of one or more of the first and second pressure thresholds Pi t h / P 2 th is then based on this determined operating point.
  • the information related to the road section ahead of the vehicle 100 may include information related to a speed limit for the road section, a topology of the road section, a curvature of the road section and/or a traffic situation within the road section.
  • the first pressure threshold Pi th may for example be reduced if the upcoming road section includes a lower speed limit, a downhill stretch, one or more curves and/or slow moving traffic .
  • the first pressure threshold Pi th may for example be increased if the upcoming road section includes a higher speed limit, an uphill stretch, one or more straight sections curves and/or fast moving, or no, traffic.
  • the second pressure threshold P 2 th may be reduced and/or increased based on if the upcoming road section includes one or more uphill and/or downhill stretches, one or more curves, and/or one or more stretches with slow moving traffic and/or fast moving traffic.
  • the information related to the road section ahead of the vehicle 100 may e.g. be based on positioning information, map information, topology information, information provided by at least one other vehicle or at least one infrastructure device (V2V, V2I, V2X) 170, and/or information gathered by the vehicle 100 itself at an earlier point in time.
  • V2V, V2I, V2X infrastructure device
  • the determination of the operating point may, according to various embodiments of the present invention, be performed based also on information related to essentially any parameter being relevant for influencing and/or determining the behavior of the vehicle when travelling on the upcoming road section.
  • the information may for example be related vehicle positioning information, digital map information, topographical
  • curvature information curvature information, speed limit information, traffic information, radar-based information, camera-based information, requested vehicle speed information, other vehicle distance information, other vehicle speed information, vehicle weight information, information obtained from other vehicles than the vehicle 100, road information and/or
  • the information related to the upcoming road section may be obtained in various ways. It may be determined on the basis of map data, e.g. from digital maps including e.g. topographical information, in combination with positioning information, e.g. GPS (global positioning system) information. The positioning information may be used to determine the location of the vehicle relative to the map data so that the road section information may be extracted from the map data.
  • map data e.g. from digital maps including e.g. topographical information
  • positioning information e.g. GPS (global positioning system) information.
  • the positioning information may be used to determine the location of the vehicle relative to the map data so that the road section information may be extracted from the map data.
  • GPS global positioning system
  • Such systems may then provide the system for the present invention with map data and positioning information, thereby minimizing the additional complexity involved in determining the road gradient.
  • the road section information may thus e.g. be obtained on the basis of a map in conjunction with GPS information.
  • the information may also be obtained by usage of radar equipment, one or more cameras, one or more other vehicles providing information, information storing systems on board, and/or traffic systems related to the section of road.
  • the information may be used for performing simulations related to the vehicle 100 for the upcoming road section, such as e.g. on or more future speed profiles for the actual vehicle speed for the road section.
  • the one or more simulations may be used for performing simulations related to the vehicle 100 for the upcoming road section, such as e.g. on or more future speed profiles for the actual vehicle speed for the road section.
  • the one or more simulations may be used for performing simulations related to the vehicle 100 for the upcoming road section, such as e.g. on or more future speed profiles for the actual vehicle speed for the road section.
  • the one or more simulations may be used for performing simulations related to the vehicle 100 for the upcoming road section, such as e.g. on or more future speed profiles for the actual vehicle speed for the road section.
  • the one or more simulations may be used for performing simulations related to the vehicle 100 for the upcoming road section, such as e.g. on or more future speed profiles for the actual vehicle speed for the road section.
  • the one or more simulations may be
  • the simulations may be conducted on board the vehicle at a predetermined rate, e.g. at a rate of 1 Hz, which means that a new simulation result is provided every second.
  • the section of road for which the simulation is conducted represents a predetermined distance ahead of the vehicle, e.g. it might be 1 km long.
  • the section of road may also be regarded as a horizon ahead of the vehicle, for which the simulation is to be conducted.
  • the maximal liquid torque T max n q is used in various embodiments of the present invention.
  • the maximal liquid torque T max iiq may, according to an embodiment, be determined adaptively during normal operation of the vehicle, i.e. when the engine 101 runs. The determination of the maximal liquid torque T max n q is then based on a performance of the engine 101. For example, information related to the control of the fluid flows, i.e. control of the electrically controlled economizer 127, is stored and is utilized, together with the performance of the engine 101 resulting from the controlled flows, i.e. resulting from the control of the economizer, for the adaptive determination of the maximal liquid torque T max liq .
  • a value of the maximal liquid torque Tmax iiq may here for example be actively adjusted, and
  • the maximal liquid torque T max iiq is adaptively determined based on that executed/performed active adjustment and on a performance of the engine 101 resulting from the active adjustment of the maximal liquid torque T max iiq .
  • a change/adjustment of the maximal liquid torque T max iiq is here first actively effected, and thereafter the effect of this change/adjustment is analyzed. The analysis is then possibly followed by another adj ustment/change of the maximal liquid torque T max iiq , and so on.
  • the maximal liquid torque T max n q is determined by running a test engine corresponding to the engine 101 used in the vehicle 100 on the liquid state fuel 126 in a test cell/laboratory
  • the maximal liquid torque T max n q is determined 410 by first determining a tendency for engine knocking when the fuel in the liquid state is provided to the engine, e.g. based on information provided by one or more knocking sensors, which may be acoustic sensors, arranged at the engine 101 and/or based on a knowledge of the octane number of the fuel provided to the engine.
  • the maximal liquid torque T max iiq may be determined based on the determined
  • the gaseous liquid torque T max gas may be determined based on the determined tendency, by adjusting the ignition until the knocking stops, as mentioned above. The gaseous liquid torque T max gas is then determined as the torque providable without engine knocking occurring.
  • providable by the engine 101 may be performed by running a test engine corresponding to the engine 101 in the vehicle 100 e.g. in a test cell/laboratory environment, and measuring a resulting maximal gaseous torque T max gas .
  • embodiments of the method for controlling a state of fuel provided from a fuel tank 121 to an engine 101 may also be implemented in a computer program, which, when it is executed in a computer, instructs the computer to execute the method.
  • the computer may be included in the herein described system and/or may be
  • the computer program is usually constituted by a computer program product 603 stored on a non-transitory/non-volatile digital storage medium, in which the computer program is incorporated in the computer-readable medium of the computer program product.
  • the computer-readable medium comprises a suitable memory, such as, for example: ROM (Read-Only Memory), PROM (Programmable Read- Only Memory) , EPROM (Erasable PROM) , Flash memory, EEPROM (Electrically Erasable PROM), a hard disk unit, etc.
  • Figure 6 shows in schematic representation a control
  • control unit/system/means 600/140 The control unit/system/means
  • 600/140 comprises a computing unit 601, which may be
  • the computing unit 601 is connected to a memory unit 602 arranged in the control unit/system/means 600/140, which memory unit provides the computing unit 601 with, for example, the stored program code and/or the stored data which the computing unit 601 requires to be able to perform computations.
  • the computing unit 601 is also arranged to store partial or final results of computations in the memory unit 602.
  • control unit/system/means 600/140 is provided with devices 611, 612, 613, 614 for receiving and transmitting input and output signals.
  • These input and output signals may comprise waveforms, impulses, or other attributes which, by the devices 611, 613 for the reception of input signals, can be detected as information and can be converted into signals which can be processed by the computing unit 601. These signals are then made available to the computing unit 601.
  • the devices 612, 614 for the transmission of output signals are arranged to convert signals received from the computing unit 601 in order to create output signals by, for example, modulating the signals, which can be transmitted to other parts of and/or systems within or outside the vehicle.
  • Each of the connections to the devices for receiving and transmitting input and output signals can be comprise one or more of a cable; a data bus, such as a CAN bus
  • Controller Area Network bus Controller Area Network bus
  • MOST Media Orientated Systems Transport bus
  • some other bus configuration or by a wireless connection.
  • a person skilled in the art will appreciate that the above-stated computer can be constituted by the computing unit 601 and that the above-stated memory may be constituted by the memory unit 602. Control systems in modern vehicles commonly comprise
  • communication bus systems including one or more
  • Such a control system may comprise a large number of control units/means and the responsibility for a specific function can be divided amongst more than one control unit/means.
  • Vehicles of the shown type thus often comprise significantly more control units/means than are shown in figures 1, 2 and 6, which is well known to the person skilled in the art within this technical field.
  • the present invention is implemented in the control unit/system/means 600/140.
  • the invention can also, however, be implemented wholly or partially in one or more other control units/systems/means already present in the vehicle, or in some control unit/system/means dedicated to the present invention.
  • a control unit 140 arranged for controlling a state of fuel provided from a fuel tank 121 to an engine 101 of a vehicle 100 is presented.
  • the fuel tank 121 stores fuel in gaseous 125 and liquid 126 state, and includes at least one gaseous fuel output conduit 122 and at least one liquid fuel output conduit 123.
  • the control unit 140 includes a determination unit/means 141, arranged for determining 410 at least one upcoming operating point for the engine 101 based on one or more of information related to an upcoming usage of a vehicle 100 including the engine 101 and the fuel tank 121, and information related to a road section ahead of the vehicle 100.
  • the control unit 140 further includes adjustment unit/means 142, arranged for adjusting 420, based on the determined at least one upcoming operation point, one or more of a first pressure threshold Pi t h and a second pressure threshold P 2 th ⁇
  • the first pressure threshold Pi th indicates a pressure below which only the fuel in liquid state 126 is provided to the engine 101
  • the second pressure threshold P 2 th indicates a pressure above which only the fuel in the gaseous state 125 is provided to the engine 101.
  • the control unit 140 also includes control unit/means 143, arranged for controlling 430 fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 based on at least one or more of the first pressure threshold P 2 th and the second pressure threshold P 2 t h ⁇
  • units/means are often described as being arranged for performing steps of the method according to the invention. This also includes that the units/means are designed to and/or configured to perform these method steps.
  • the at least one control unit 140 is in figures 1 and 2 illustrated as including separately illustrated units/means 141, 142, 143.
  • the control system/means 140 may include or be coupled to other control means/units, such as e.g. an engine control device/means, a clutch control unit, an exhaust treatment system control unit, and/or a gearbox control unit.
  • These means/units/devices 141, 142, 143, 140 may, however, be at least to some extent logically separated but implemented in the same physical unit/device.
  • These means/units/devices 141, 142, 143, 140 may also be part of a single logic unit which is implemented in at least two different physical units/devices.
  • These means/units/devices 141, 142, 143, 140 may also be at least to some extent logically separated and implemented in at least two different physical means/units/devices. Further, these means/units/devices 141, 142, 143, 140 may be both logically and physically arranged together, i.e. be part of a single logic unit which is implemented in a single physical means/unit/device . These means/units/devices 141, 142, 143,
  • control unit/means 140 may for example correspond to groups of instructions, which can be in the form of programming code, that are input into, and are utilized by at least one processor when the units/means are active and/or are utilized for performing its method step, respectively. It should be noted that the control unit/means 140 may be implemented at least partly within the vehicle 100 and/or at least partly outside of the vehicle 100, e.g. in a server, computer, processor or the like located separately from the vehicle 100.
  • the units 141, 142, 143 described above correspond to the claimed means 141, 142, 143 arranged for performing the embodiments of the present invention, and the present invention as such.
  • control unit can be arranged for performing all of the above, in the claims, and in the herein described embodiments method steps.
  • the control unit is hereby provided with the above described advantages for each respective embodiment.
  • control unit may be modified according to the different embodiments of the method of the present invention.
  • the present invention is also related to a vehicle 100, such as a truck, a bus or a car, including the herein described control unit 140.
  • inventive method, and embodiments thereof, as described above may at least in part be performed with/using/by at least one device.
  • the inventive method, and embodiments thereof, as described above, may be performed at least in part with/using/by at least one device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof.
  • a device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof may be one, or several, of a control unit, an electronic control unit (ECU) , an electronic circuit, a computer, a computing unit and/or a processing unit .
  • ECU electronice control unit
  • embodiments thereof may be referred to as an, at least in part, computerized method.
  • the method being, at least in part, computerized meaning that it is performed at least in part with/using/by the at least one device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof.
  • embodiments thereof, as described above, may be referred to as an, at least in part, automated method.
  • the method being, at least in part, automated meaning that it is performed
  • the at least one device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof.

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Abstract

A method and control unit for controlling a state of fuel provided from a fuel tank to an engine are presented. The fuel tank stores fuel in gaseous and liquid state, and includes at least one gaseous fuel output conduit and at least one liquid fuel output conduit. The method includes: - determining at least one upcoming operating point for said engine based on one or more of information related to an upcoming usage of a vehicle including said engine and said fuel tank, and information related to a road section ahead of said vehicle; - adjusting one or more of a first pressure threshold P1_th and a second pressure threshold P2_th, wherein said first pressure threshold P1_th indicates a pressure below which only said fuel in liquid state is provided to said engine, and said second pressure threshold P2_th indicates a pressure above which only said fuel in said gaseous state is provided to said engine; And - controlling fuel flows through one or more of said fuel output conduits.

Description

METHOD AND SYSTEM FOR CONTROLLING A STATE OF FUEL PROVIDED TO AN ENGINE
Field of invention
The present invention relates to a method for controlling a state of fuel provided from a fuel tank to an engine, as defined in the preamble of claim 1. The present invention also relates to a control unit arranged for controlling a state of fuel provided from a fuel tank to an engine, as defined in the preamble of claim 15. The present invention also relates to a computer program and a computer-readable medium comprising instructions for carrying out the method according to the invention .
Background of invention
The following background information is a description of the background of the present invention, which thus not
necessarily has to be a description of prior art.
Vehicles, such as for example cars, buses and trucks, are driven forward by an engine torque produced by an engine in the vehicle. This engine torque is provided to the driving wheels of the vehicle through a powertrain. The torque may be created at least partly in a combustion engine by combustion of fuel being injected into the engine, i.e. injected into the cylinders of the engine.
The fuel used for the combustion in the engine may for example include liquified natural gas (LNG) . Such liquified natural gas (LNG) is often stored in at least one pressurized fuel tank. In the tank, fuel in gaseous and liquid state is stored. The pressurized fuel tank includes a gaseous fuel output conduit in contact with the gaseous state fuel, and a liquid fuel output conduit in contact with the liquid state fuel. Thus, liquid state fuel may be provided to the engine through the liquid fuel output conduit, and gaseous state fuel may be provided to the engine through the gaseous fuel output
conduit .
The pressure Pgas of the gaseous state fuel is used as, or is at least related to, a drive pressure Pdrive utilized for pushing the fuel out from the pressurized tank, i.e. utilized for driving the fuel out through the liquid or gaseous fuel output conduits. Therefore, the pressure Pgas of the gaseous state fuel has to be high enough, i.e. above a minimum gas pressure threshold Pgas min/ in order to be able to push the fuel out from tank. However, in order to prevent the pressurized tank from exploding, the pressure Pgas of the gaseous fuel may not be allowed to increase above a maximal gas pressure threshold Pgas max/ which for example may have a value in the region of 20 bar. A safety valve may be arranged for opening the valve when the gaseous pressures Pgas reaches the maximal gas pressure threshold Pgas max/ thereby letting gaseous state fuel pass out to the ambient air in order to reduce the gaseous pressure Pgas .
Generally, the gaseous state fuel has a higher octane
number/rating than the liquid state fuel has, since the lighter hydrocarbons are evaporated from the liquid state fuel when the gaseous state fuel is created. The liquid state fuel includes a mixture of various hydrocarbons providing a lower octane number/rating than the evaporated lighter hydrocarbons in the gaseous state fuel result in.
However, gaseous state fuel takes up a much greater volume than liquid state fuel due to its much lower density.
Therefore, the pressurized fuel tank should at least partly include fuel in liquid form in order to provide an acceptable reach/range for a vehicle comprising the tank and the engine. The differing octane numbers/ratings for the gaseous and liquid states of the fuel may be used such that the liquid state fuel is used under some conditions and that the gaseous state fuel is used under other conditions. For example, the gaseous state fuel may be used when a higher torque is
requested, e.g. for acceleration or uphill driving. To achieve this, a mechanical economizer has in conventional solutions been arranged to switch between supplying liquid state fuel and gaseous state fuel to the engine. Such a mechanical economizer has e.g. been arranged as a mechanical switch, which is able to switch between connecting the gaseous fuel output conduit of the tank to the engine and connecting the liquid fuel output conduit to the engine.
SUMMARY OF INVENTION
The mechanical economizer used in conventional solutions is arranged to switch between providing liquid and gaseous state fuel to the engine at a gas pressure Pgas corresponding to a predetermined switch threshold Pgas sw th of the gaseous state fuel, often having a value corresponding to a gas pressure Pgas of 12 bar; Pgas = 12 bar. For example, if the gas pressure Pgas of the gaseous state fuel is increased above the switch threshold Pgas sw th/ the economizer switches to provide only gaseous state fuel to the engine. Correspondingly, if the gas pressure Pgas of the gaseous state fuel is decreased below the switch threshold Pgas sw th, the economizer switches to provide only liquid state fuel to the engine.
However, due to component individual variations, different mechanical economizer individuals may switch at different gaseous pressures Pgas, although they are all designed to switch at the threshold Pgas sw th · Thus, different mechanical economizer individuals may provide different states (gaseous/fluid) of the fuel to its respective engines at the same gaseous Pgas ·
The state of the fuel being provided to the engine has an influence on the pressure Pgas of the gaseous fuel, and
therefore has an influence on the drive pressure Pdrive used for pushing the fuel to the engine. Generally, if gaseous state fuel is provided to the engine, the pressure Pgas of the gaseous fuel is decreased.
Further, the component individual variations may also result in an unreliable control of the state of fuel being provided to the engine. There is therefore a risk that engine knocking might occur, since the octane number/rate of the fuel provided to the engine is not reliably controlled. Thus, the
uncertainty of the conventionally used mechanical economizer may cause engine control difficulties. If it cannot be
guaranteed that there is enough gaseous state fuel available for combustion in the engine there is a risk that the engine is not able to provide a torque Treq being requested. This may by a driver be perceived as the vehicle being weak, and may in some situations be hazardous.
It is therefore an object to solve at least some of the above- mentioned disadvantages.
The object is achieved by the above mentioned method for controlling a state of fuel provided from a fuel tank to an engine, the fuel tank storing fuel in gaseous and liquid state, and including at least one gaseous fuel output conduit and at least one liquid fuel output conduit according to the characterizing portion of claim 1, the method including:
- determining at least one upcoming operating point for the engine based on one or more of information related to an upcoming usage of a vehicle including the engine and the fuel tank, and information related to a road section ahead of the vehicle ;
- adjusting, based on the determined at least one upcoming operation point, one or more of a first pressure threshold Pi th and a second pressure threshold P2 th/ wherein the first
pressure threshold Pi th indicates a pressure below which only the fuel in liquid state is provided to the engine, and the second pressure threshold P2 th indicates a pressure above which only the fuel in the gaseous state is provided to the engine; and
- controlling fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit based on at least one or more of the first pressure threshold Pi th and the second pressure threshold P2 th ·
Hereby, an increased flexibility for the control of the state of fuel being provided to the engine is achieved. The state of fuel and/or the mixture/ratio of states of fuel being provided to the engine may be tailored such that the torque provided by the engine is adapted to the upcoming usage of the vehicle.
By adjusting one or more of the first pressure threshold Pi th and the second pressure threshold P2 th, a pressure interval Pi th - P2 th is also adjusted. This pressure interval Pi th - P2 th may then be intelligently utilized for matching the upcoming usage of the vehicle with a suitable state of fuel. Thus, the gaseous state fuel, having a higher octane number/rate, may be stored for known upcoming in situations when it is really needed, i.e. in situations when a requested engine torque Treq is so high that it cannot be provided by combustion of liquid state fuel.
Thus, a pressure region/interval Pi th - P2 th between the first pressure threshold Pi th and the second pressure threshold P2 th is defined, adjusted and/or used by some embodiments of the present invention. This pressure region Pi th - P2 th does not even exist for a conventional mechanical economizer, since the conventional mechanical economizer switches only based on the pressure. The pressure region Pi th - P2 th created by the embodiments of the present invention may be utilized for controlling the electronic controllable economizer e.g. in relation to an upcoming requested engine torque Treq. Hereby, a more efficient usage of the gaseous state fuel, and thereby also a more powerful engine, may be achieved.
Thus, by usage of the present invention, it is possible to optimize the state of fuel and/or the ratio between gaseous and liquid states of fuel being provided to the engine, in order to be able to match future needs of the engine.
Also, the present invention facilitates a reliable and
accurate control of the controllable electronic economizer, which enables that higher torques may be provided by the engine when needed, since more gaseous state fuel (having higher octane number/rate) will be available for being
provided to the engine when needed.
According to an embodiment of the present invention, the adjusting of one or more of the first pressure threshold Pi th and the second pressure threshold P2 th is performed such that an amount of fuel in the gaseous state needed for the engine to reach the at least one upcoming operating point is
available in the tank.
Hereby, it is secured that the higher octane number/rate gaseous state fuel will be available for usage in future situations when it is really needed.
According to an embodiment of the present invention, the information related to the upcoming usage includes one or more of :
- external information;
- internal information;
- driver inputted information;
- information provided by at least one other vehicle;
- information provided by at least one external database;
- information provided by a tachograph;
- information related to a driving schedule;
- information related to a loading schedule;
- information related to a service schedule; and
- information related to a weight of the vehicle.
Since the determination of the at least one upcoming operating point for the engine may be based on one or more of a large number of different information, a reliable and accurate determination can be made in any situation.
According to an embodiment of the present invention, the upcoming usage includes one or more of:
- a permanent break and/or stop;
- a break and/or stop time period Tstop longer than a stop time threshold Tstop-th;
- a number of breaks and/or stops Nstop greater than a number threshold, fbtoP ^ b/toP th^
- a number of breaks and/or stops Nstop smaller than a number threshold, fbtoP ^ b/toP th^
- a usage resulting in an engine load Len greater than a load threshold Len th Len Len th
- a usage resulting in an engine load Len smaller than a load threshold Len th Len Len th
- a usage resulting in a vehicle weight W greater than a weight threshold Wth/ W > Wth/ and
- a usage resulting in a vehicle weight W smaller than a weight threshold Wth/ W < Wth-
Hereby, the determination of the at least one upcoming operating point for the engine may be reliably and accurately determined .
According to an embodiment of the present invention, the information related to the road section ahead of the vehicle includes one or more of:
- a speed limit for the road section;
- a topology of the road section;
- a curvature of the road section,
- a traffic situation within the road section.
Hereby, the determination of the at least one upcoming operating point for the engine may be reliably and accurately determined .
According to an embodiment of the present invention, the information related to the road section ahead of the vehicle is based on one or more of:
- positioning information;
- map information;
- topology information;
- information provided by at least one other vehicle;
- information provided by at least one infrastructure device; and
- information gathered by the vehicle at an earlier point in time .
Hereby, the determination of the at least one upcoming operating point for the engine may be reliably and accurately determined . According to an embodiment of the present invention, the controlling of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is performed such that only the fuel in the gaseous state is provided to the engine if a gaseous pressure Pgas of the gaseous state fuel is greater than the second pressure threshold P2 th! Pgas > P2 th ·
Hereby, the risk for having to open the safety valve is reduced, whereby also a reduction of the fuel consumption is achieved over time.
According to an embodiment of the present invention, the controlling of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is performed such that only the fuel in the liquid state is provided to the engine if a gaseous pressure Pgas of the gaseous state fuel is smaller than the first pressure threshold Pi th/ Pgas < Pi th·
Hereby, is it secured that the gas pressure Pgas is high enough for being able to push the fuel out from the tank, and to the engine, i.e. that a high enough drive pressure Pdrive is available .
According to an embodiment of the present invention, the controlling of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is based on a requested engine torque Treq if a gaseous pressure Pgas of the gaseous state fuel is greater than the first pressure threshold Pi th and smaller than the second pressure threshold P2 th ; Pi th < Pgas < P2 th ·
Hereby, an adaption of the ratios between gaseous and liquid state fuel being provided to the engine is adapted in relation to the requested torque Treq. The engine is then provided with the fuel it needs to provide the requested torque Treq, at the same time as no valuable gaseous state fuel is unnecessarily wasted. Instead, the higher octane number/rate gaseous state fuel is saved for usage in situations when it is really needed .
According to an embodiment of the present invention, the adjusting of the first pressure threshold Pi th results in a value of the first pressure threshold Pi th being greater than a minimum first pressure threshold value Pi th min/ the minimum first pressure threshold value Pi th min being related to a capability of the fuel tank to provide the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit.
Hereby, is it secured that the gas pressure Pgas is high enough for being able to push the fuel out from the tank, and to the engine .
According to an embodiment of the present invention, the adjusting of the second pressure threshold P2 th results in a value of the second pressure threshold P2 th being smaller than a maximum second pressure threshold value P2 th max/ the maximum second pressure threshold value P2 th max being related to a maximally allowed pressure Pgas max for the fuel tank.
Hereby, the risk for wasting fuel due to opening of the safety valve is reduced, since the second pressure threshold P2 th is determined in relation to the maximally allowed pressure Pgas max for the tank, i.e. in relation to a safety valve release pressure. For example, the herein described second pressure threshold P2 th may, according to an embodiment, be equal to the maximally allowed pressure Pgas max for the tank minus a safety
Offset Pgas_offset/ ?2_th — Pgas_max — Pgas_offset/ Where the Safety offset Pgas offset has a value providing a reasonable margin to the safety valve release pressure, i.e. to the maximally allowed pressure Pgas max ·
According to an embodiment of the present invention, the fuel in the gaseous state has a higher octane number than the fuel in the liquid state.
The recognition of the various octane numbers/rates for various fuel states is utilized by the embodiments of the present invention.
The object is also achieved by the above mentioned control unit arranged for controlling a state of fuel provided from a fuel tank to an engine, the fuel tank storing fuel in gaseous and liquid state, and including at least one gaseous fuel output conduit and at least one liquid fuel output conduit, according to the characterizing portion of claim 15. The control unit includes:
- means arranged for determining at least one upcoming operating point for the engine based on one or more of information related to an upcoming usage of a vehicle
including the engine and the fuel tank, and information related to a road section ahead of the vehicle;
- means arranged for adjusting, based on the determined at least one upcoming operation point, one or more of a first pressure threshold Pi th and a second pressure threshold P2 th/ wherein the first pressure threshold Pi th indicates a pressure below which only the fuel in liquid state is provided to the engine, and the second pressure threshold P2 th indicates a pressure above which only the fuel in the gaseous state is provided to the engine; and
- means arranged for controlling fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit based on at least one or more of the first pressure threshold Pi th and the second pressure threshold P2 th ·
The control unit has the same advantages as stated above for the method.
According to an embodiment of the present invention, the adjusting means is arranged for performing the adjusting of one or more of the first pressure threshold Pi th and the second pressure threshold P2 th such that an amount of the fuel in the gaseous state needed for the engine to reach the at least one upcoming operating point is available in the tank.
According to an embodiment of the present invention, the information related to the upcoming usage includes one or more of :
- external information;
- internal information;
- driver inputted information;
- information provided by at least one other vehicle;
- information provided by at least one external database;
- information provided by a tachograph;
- information related to a driving schedule;
- information related to a loading schedule;
- information related to a service schedule; and
- information related to a weight of the vehicle.
According to an embodiment of the present invention, the upcoming usage includes one or more of:
- a permanent break and/or stop;
- a break and/or stop time period Tst0p longer than a stop time threshold Tstop_th;
- a number of breaks and/or stops Nst0p greater than a number threshold, Pbtop ^ Pbtop th ^ - a number of breaks and/or stops Nst0p smaller than a number threshold, bftop ^ bftop th^
- a usage resulting in an engine load Len greater than a load threshold Len th hen ^ hen th
- a usage resulting in an engine load Len smaller than a load threshold hen th hen Len th
- a usage resulting in a vehicle weight W greater than a weight threshold Wth/ W > Wth/ and
- a usage resulting in a vehicle weight W smaller than a weight threshold Wth/ W < Wth-
According to an embodiment of the present invention, the information related to the road section ahead of the vehicle includes one or more of:
- a speed limit for the road section;
- a topology of the road section;
- a curvature of the road section,
- a traffic situation within the road section.
According to an embodiment of the present invention, the information related to the road section ahead of the vehicle is based on one or more of:
- positioning information;
- map information;
- topology information;
- information provided by at least one other vehicle;
- information provided by at least one infrastructure device; and
- information gathered by the vehicle at an earlier point in time .
According to an embodiment of the present invention, the control means is arranged for performing the control of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit such that only the fuel in the gaseous state is provided to the engine if a gaseous pressure Pgas of the gaseous state fuel is greater than the second pressure
threshold P2_th; Pgas > P2_th .
According to an embodiment of the present invention, the control means is arranged for performing the control of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit such that only the fuel in the liquid state is
provided to the engine if a gaseous pressure Pgas of the gaseous state fuel is smaller than the first pressure
threshold Pi_th; Pgas < Pi_th.
According to an embodiment of the present invention, the control means is arranged for performing the control of the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit is based on a requested engine torque Treq if a gaseous pressure Pgas of the gaseous state fuel is greater than the first pressure threshold P2 th and smaller than the second pressure threshold P2 th/ Pi th < Pgas < P2 th ·
According to an embodiment of the present invention, the adjustment means is arranged for adjusting the first pressure threshold P2 th such that it results in a value of the first pressure threshold Pi th being greater than a minimum first pressure threshold value Pi th min/ the minimum first pressure threshold value Pi th min being related to a capability of the fuel tank to provide the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit. According to an embodiment of the present invention, the adjustment means is arranged for adjusting the second pressure threshold P2 th such that it results in a value of the second pressure threshold P2 th being smaller than a maximum second pressure threshold value P2 th max/ the maximum second pressure threshold value P2 th max being related to a maximally allowed pressure Pgas max for the fuel tank.
According to an embodiment of the present invention, the fuel in the gaseous state has a higher octane number than the fuel in the liquid state.
The object is also achieved by the above mentioned computer program and computer-readable medium.
Detailed exemplary embodiments and advantages of the method, control unit, computer program and computer-readable medium according to the invention will below be described with
reference to the appended drawings illustrating some preferred embodiments .
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are described in more detail with reference to attached drawings illustrating examples of embodi ments of the invention in which:
Figure 1 is a schematic illustration of a non-limiting example of a vehicle in which the embodiments of the present invention may be implemented,
Figure 2 is a schematic illustration of a fuel providing system, in which the embodiments of the present invention may be implemented, Figures 3a-b show a conventional economizer and valves that may be used according to some embodiments of the present invention, respectively,
Figure 4 shows a flow chart diagram for some embodiments of the present invention,
Figure 5a-b schematically illustrates various pressure regions and actions made according to some embodiments of the present invention, and
Figure 6 is a schematic illustration of a control unit
according to some embodiments of the present invention.
DETAILED DESCRIPTION OF INVENTION
Figure 1 schematically shows an example vehicle 100, such as a truck, a bus, a car, or another suitable vehicle, which will be used to explain the present invention. The present
invention is, however, not limited to use in heavy goods vehicles as the one shown in figure 1, but may also be used in essentially any vehicle, such as lighter vehicles, e.g.
passenger cars.
The vehicle 100, shown schematically in figure 1, comprises an engine 101, which may comprise a combustion engine, e.g. an engine consuming liquified natural gas (LNG) , in order to create a torque being provided for driving the vehicle, e.g. a diesel engine, or an engine working according to the Otto cycle for which an electric spark ignites a fuel and air mixture in the engine cylinders, e.g. a gasoline or ethanol engine. Essentially, the engine 101 may in this document comprise any device which transforms chemical energy to mechanical energy, and uses gaseous and liquid state fuel for its combustion/energy transformation. The engine then provides energy in form of a torque to the powertrain. Exhaust gases produced by the engine 101 are purified by an exhaust
treatment system 150. The vehicle 100 may also include one or more other engines and/or machines, e.g. electrical machines.
The engine 101 may, for example, in a customary fashion, via an output shaft 102 of the engine 101, be connected with a gearbox 103, via a clutch 106 and an input shaft 109 connected to the gearbox 103. An output shaft 107 from the gearbox 103, also known as a propeller shaft, drives the driving wheels 110, 111 via a final gear 108, such as e.g. a customary differential, and drive shafts 104, 105 connected with the final gear 108.
A fuel providing system 120, including at least one fuel tank 121, which may be pressurized, is arranged for providing the engine 101 with fuel. The fuel providing system 120 is
described more in detail below.
A control unit 140 is in figure 1 schematically illustrated as receiving signals and/or providing control signals from and/or to the engine 101 and/or the pressurized fuel tank 121. The control unit 140 may also receive and/or provide control signals to and/or from other devices in the vehicle 100.
According to some embodiments of the present invention, as described in this document, the control unit 140 may also comprise determining means 141, e.g. a determination unit 141, adjusting means 142, e.g. an adjustment unit 142, and control means 143, e.g. a control unit 143. These control
means/units/devices 141, 142, 143 are described more in detail below, and may be divided physically into more than the herein described control means/systems/units 140, or may be arranged in less control systems/units than herein described.
As mentioned above, and as schematically illustrated in figure 2, the fuel used for the combustion in the engine 101 may for example include gaseous 125 and liquid 126 state fuel, such as e.g. states of a liquified natural gas (LNG) . Such gaseous and liquid state fuel is stored in a fuel tank 121, which often is a pressurized fuel tank. The fuel tank includes a gaseous fuel output conduit 122 in contact with the gaseous state fuel 125, and a liquid fuel output conduit 123 in contact with the liquid state fuel 126. Liquid state fuel 126 may therefore be provided to the engine through the liquid fuel output conduit 123, and gaseous state fuel 125 may be provided to the engine through the gaseous fuel output conduit 122. The tank 121 may include the above mentioned safety valve 124 arranged for opening the valve 124 if the gaseous pressures Pgas reaches the maximal gas pressure threshold Pgas max · Hereby, the gaseous state fuel is allowed to pass out into the ambient air outside of the system/vehicle, which efficiently limits and/or reduces the gaseous pressure Pgas .
Conventional fuel providing systems 120 have been equipped with the above mentioned mechanical economizer, schematically illustrated in figure 3a, arranged to switch between
connecting either the gaseous fuel output conduit 122 or the liquid fuel output conduit 123 to the engine, e.g. via a fuel arrangement 128, such as pipe and/or a tube. The conventional mechanical economizer has the above mentioned
drawbacks/disadvantages .
The present invention, and its embodiments, may instead utilize an electronically controlled economizer 127
schematically illustrated in figure 3b. The electronically controlled economizer 127 includes at least one controllable valve 129 arranged in at least one of the gaseous fuel output conduit 122 and the liquid fuel output conduit 123. For example, one such electronically controllable valve 129 may be arranged at each one of the the gaseous fuel output conduit 122 and the liquid fuel output conduit 123. By usage of the electronically controlled economizer 127, the portions/ratios of gaseous 125 and liquid 126 state fuel to be provide to the engine, e.g. via a fuel arrangement 128, may easily be
achieved. Thus, by usage of the electronically controlled economizer 127, it is not only possible to choose to provide either gaseous or liquid state fuel to the engine (as for the conventional mechanical economizer in figure 3a) . Instead, it is possible to control the controllable at least one valve 129 of the electronically controlled economizer 127 such that essentially any combination/mixture of gaseous 125 and liquid 126 state fuel is provided to the engine. Thus, essentially any ratio of gaseous 125 and liquid 126 fuel, and therefore also any variety of possible octane numbers/rates, may hereby be provided to the engine by the control of the at least one controllable valve 129.
Figure 4 shows a flow chart diagram for a method 400 according to an embodiment of the present invention, i.e. a method for controlling a state of fuel provided from a fuel tank 121 to an engine 101, wherein the fuel tank 121 is storing fuel in gaseous 125 and liquid 126 state. The tank 121 includes at least one gaseous fuel output conduit 122 and at least one liquid fuel output conduit 123.
The method steps of figure 4 may be performed in another order than the order illustrated in figure 4, as long as the
information needed for performing a step is available when the step is to be performed.
In a first step 410 of the method, e.g. performed by use of a below described determination unit/means 141, at least one upcoming operating point for the engine 101 is determined based on one or more of information related to an upcoming usage of a vehicle 100 including the engine 101 and the fuel tank 121, and information related to a road section ahead of the vehicle 100.
In a second step 420 of the method, performed e.g. by use of a below described adjustment unit/means 142, one or more of a first pressure threshold Pi th and a second pressure threshold P2 th are adjusted based on the determined at least one upcoming operation point. The first pressure threshold Pith indicates a pressure below which only fuel in liquid state 126 is to be provided to the engine 101. The second pressure threshold P2 th indicates a pressure above which only fuel in the gaseous state 125 is to be provided to the engine 101.
In a third step 430 of the method, performed e.g. by use of a below described control unit/means 143, fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 is
controlled based on at least one or more of the first pressure threshold Pi th and the second pressure threshold P2 th · As mentioned above, the control of the fuel flows may include control of at least one controllable valve 129 arranged in at least one of the gaseous fuel output conduit 122 and the liquid fuel output conduit 123.
By usage of the present invention, an increased flexibility for the control of the state of fuel being provided to the engine is achieved. The state of fuel and/or the mixture of states of fuel being provided to the engine may be tailored such that the torque provided by the engine is adapted to the upcoming usage of the vehicle 100.
By adjusting one or more of the first pressure threshold P2 th and the second pressure threshold P2 th based on the determined at least one upcoming operation point, a pressure interval P2 th - P2 th between the first pressure threshold Pi th and the second pressure threshold P2 th is adjusted, as is illustrated in figure 5a. The first pressure threshold Pi th may here be adjusted within a region defined by a minimum Pi th min and a maximum Pi_th_max value; Pi_th_min < Pi_th < Pi_th_max· For example, the minimum first pressure threshold Pi th min may, according to an embodiment, be equal to the pressure Pgas min needed for
providing the fuel flows through one or more of the at least one gaseous fuel output conduit and the at least one liquid fuel output conduit. The second pressure threshold P2 th may correspondingly be adjusted within a region defined by a minimum P2_th_min and a maximum P2_th_max value; P2-th_min < P2_th <
P2 th max· These regions are schematically illustrated in figure 5a .
Then when adjusting the first pressure threshold Pi th and/or the second pressure threshold P2 th/ the resulting threshold values should be within suitable regions/ranges, as
illustrated in figure 5a. For example, the adjusted first pressure threshold value Pi th should be greater than a minimum first pressure threshold value Pi th min/ which is related to a capability of the fuel tank 121 to provide the fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123, as mentioned above. Also, the adjusted second pressure threshold value P2 th should for example be smaller than a maximum second pressure threshold value P2 th max/ which is related to a maximally allowed pressure Pgas max for the fuel tank 121. Basically, the second pressure threshold P2 th indicates a pressure over which the gaseous state fuel in the tank 121 needs to be reduced in order to avoid the gas
pressure Pgas reaching a maximally allowed pressure Pgas max for the tank, thereby triggering an opening of the safety valve 124, which would waste valuable gaseous state fuel.
Within the pressure interval Pi th - P2 th/ the state of the fuel provided to the engine may be intelligently/ flexibly chosen based on one or more parameters. One such example is
illustrated in figure 5b, wherein the requested torque Treq, which could be either a currently requested torque or a torque that will be requested during an upcoming road section, is used as a parameter. For example, the fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 may be controlled such that the fuel provided to the engine 101 includes a majority, i.e. > 50%, of the fuel in the liquid state 126 if the requested engine torque Treq is lower than or equal to a maximal liquid torque Tmax iiq; Treq £ Tmax iiq. However, if requested engine torque Treq is higher than the maximal liquid torque Tmax iiq; Treq > Tmax iiq; the fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 are controlled such that only the fuel in the gaseous state 125 is provided to the engine 101
The first pressure threshold Pith may here be related to, e.g. may according to an embodiment be as low as
corresponding/equal to, the above mentioned minimum gas pressure Pgas min needed for pushing the fuel out from the tank 121; Pi th = Pgas min and may as a non-limiting example have a value corresponding to a gas pressure Pgas of 10 bar; Pgas = 10 bar. The second pressure threshold P2_th may indicate a pressure over which an amount of the gaseous state fuel 125 in the tank 121 needs to be reduced in order to avoid that the pressure Pgas of the gaseous state fuel 125 reaches the
maximally allowed pressure Pgas max for the tank, which would trigger an opening of the safety valve 124. Thus, the second pressure threshold P2 th is related to the maximally allowed gas pressure Pgas max for the tank 121, and may as a non-limiting example correspond to a gas pressure Pgas of 18 bar; Pgas = 18 bar .
According to an embodiment of the present invention, when the gas pressure Pgas is within the above mentioned pressure interval Pi th - P2 th, various levels of requested torque result in various fuel state mixtures, such as 100 % fuel in the gaseous state, a mixture of the fuel in the gaseous state and in the liquid state, or 100% fuel in the liquid state. Thus, the control 430 of the fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 is based on a requested and/or upcoming engine torque Treq.
A couple of non-limiting examples of fuel state
mixtures/ratios are given in the following. One or more of such examples mixtures/ratios may, according to an embodiment of the present invention, be utilized as initial values for one or more of the embodiments of fuel state control described in this document.
According to a control algorithm, if the requested engine torque Treq is higher than the maximal liquid torque Tmax iiq; Treq > Tmax iiq; then 100% fuel in gaseous state 125, i.e. 0% fuel in liquid state 126, may be provided to the engine 101.
According to a control algorithm, if the requested engine torque Treq is lower than or equal to the maximal liquid torque Tmax nq; Treq £ Tmax iiq; then 100% fuel in liquid state 126, i.e.
0% fuel in gaseous state 125, may be provided to the engine 101. According to a control algorithm, if the requested engine torque Treq is higher than 110% of the maximal liquid torque Tmax nq; Treq > 1.1 * Tmax iiq; then 100% fuel in gaseous state 125, i.e. 0% fuel in liquid state 126, may be provided to the engine 101.
According to a control algorithm, if the requested engine torque Treq is in an interval between 80% and 110% of the maximal liquid torque Tmax nq; 0.8*Tmax nq < Treq < 1. l*Tmax nq; then a mixture of fuel in gaseous state 125 and liquid state 126 may be provided to the engine.
According to a control algorithm, if the requested engine torque Treq is higher than 90% of the maximal liquid torque Tmax nq; Treq > 0.9*Tmax iiq; then 100% fuel in gaseous state 125, i.e. 0% fuel in liquid state 126, may be provided to the engine 101.
According to a control algorithm, if the requested engine torque Treq is in an interval between 80% and 90% of the maximal liquid torque Tmax nq; 0.8*Tmax nq < Treq ^ 0.9*Tmax nq; then a mixture of fuel in gaseous state 125 and liquid state 126 may be provided to the engine.
According to a control algorithm, if the requested engine torque Treq is lower than or equal to 80% of the maximal liquid torque Tmax iiq; Treq £ 0.8*Tmax iiq; then 100% fuel in liquid state 126 may be provided to the engine 101.
As mentioned above, the first pressure threshold Pi th may, according to some embodiments, indicate a pressure below which only fuel in liquid state 126 is to be provided to the engine 101. The second pressure threshold P2 th may, according to some embodiments, indicate a pressure above which only fuel in the gaseous state 125 is to be provided to the engine 101. According to an embodiment of the present invention, a
pressure Pgas of the fuel in the gaseous state 125 is
determined. The gas pressure Pgas may e.g. be determined by usage of one or more sensors. The one or more sensors may be arranged within the tank 121 and/or with the at least one gaseous state fuel output conduit 122.
The determined pressure Pgas of the fuel in the gaseous state 125 may then be compared with the first pressure threshold Pi th · Then, if the determined pressure Pgas is lower than the first pressure threshold Pi th/ Pgas < Pi th/ the fuel flows are controlled through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 such that only fuel in liquid state 125 is provided to the engine 101.
The determined pressure Pgas of the gaseous state fuel 125 with may also be compared with the second pressure threshold P2 th ·
If the determined gas pressure Pgas is higher than the pressure threshold P2 th/ Pgas > P2 th/ fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 are controlled such that gaseous state fuel 125 is provided to the engine 101.
As mentioned above, the control of the fuel flows may be achieved by use of one or more flow controlling arrangements, including e.g. one or more valves mounted in and/or at one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123, i.e. by the use of the electrically controlled economizer 127.
According to an embodiment of the present invention, one or more of the first pressure threshold P2 th and the second pressure threshold P2 th are adjusted such that an amount of the fuel in the gaseous state 125 needed for the engine 101 to reach the at least one upcoming operating point is available in the tank 121 before the operating point occurs.
By adjusting the pressure interval Pi th - P2 th between the first pressure threshold Pi th and the second pressure threshold P2 th, the amount of gaseous state fuel 125 being available for combustion in the engine may be adapted for the upcoming usage of the vehicle 100. Hereby, fuel having a higher octane number/rate, i.e. gaseous state fuel, will to a much larger extent be available for the combustion when it is needed, e.g. when the vehicle reaches a long uphill stretch and/or should perform an acceleration. Thus, a flexible control of the state of fuel being provided to the engine is achieved, which is optimized for the actual usage of the vehicle. This is a great improvement over the conventional mechanical economizer, which performed switching only based on the gas pressure Pgas, often resulting in a shortage of gaseous state fuel when higher torques are requested.
The pressure interval Pi th - P2 th created by the embodiments of the present invention may, as is mentioned above, be utilized for an accurate control of the state of fuel being provided to the engine. Hereby, a more efficient usage of the gaseous state fuel, and thereby also a more powerful engine, may be achieved within the interval. Also, the more exact and
reliable control of the state of fuel being provided to the engine reduces the need for opening the safety valve 124, which lowers the fuel consumption over time. By adjusting the range of the pressure interval Pi th - P2 th, the pressure interval within which such an efficient and accurate usage of the gaseous state fuel is usable may be adjusted to precisely match the future/upcoming usage of the vehicle. In other words, the choice of the state of fuel to be provided to the engine may, by usage of the present invention, be coupled/matched to an upcoming usage of the vehicle, e.g. to an upcoming operational point of the vehicle and/or to an upcoming driving situation, which makes it possible to
optimize the state of fuel and/or the ratio between gaseous and liquid states of the fuel being provided to the engine.
The present invention facilitates a reliable and accurate control of the controllable electronic economizer such that future vehicle usage is taken into consideration. Hereby, the probability for the engine to be able to provide a future upcoming requested torque is greatly increased, since the amount of available gaseous state fuel will be adapted already before of the torque is requested.
An initial value, i.e. a value set before the herein described adjustment, for the first pressure threshold Pi th may be determined in a number of ways. According to an embodiment, the first pressure threshold Pi th is determined based on at least one feature of the fuel tank 121, such as for example a size, a geometrical design and/or an output conduit design for the fuel tank 121. According to an embodiment, the first pressure threshold Pi th is determined based on at least one feature of a fuel providing system 120 arranged for providing the fuel from the tank 121 to the engine 101, wherein such system features may include geometrical forms and/or
dimensions for piping between the tank 121 and the engine 101 and/or for a (common) fuel rail providing pressurized fuel to the injectors arranged for injecting fuel into the engine.
An initial value, i.e. a value set before the herein described adjustment, for the second pressure threshold P2 th may be determined in a number of ways. According to an embodiment, the second pressure threshold P2 th may be determined based on a required volume of the gaseous state fuel 125 in the tank 121 and/or on the type and/or usage of the vehicle 100. For example, a bus or a garbage truck, i.e. vehicles often
moving/driving short distances between its stops, may have a lower/smaller value for the second pressure threshold P2 th/ whereas e.g. long haulage trucks, i.e. vehicles driving/moving longer distances between its stops, may have a higher/greater value for the second pressure threshold P2 th · Further,
according to an embodiment, the second pressure threshold P2 th may be determined based on at least one feature of the fuel tank 121, a level of fuel in the fuel tank 121, a relation between amounts of the gaseous state 125 and liquid state 126 fuel in the fuel tank 121, a temperature in the fuel tank 121, an ambient temperature outside the fuel tank/system/vehicle, and/or at least one requirement related to a full tank parking time period for the vehicle 100 including the fuel tank 121.
As mentioned above, one or more of the first pressure
threshold Pi th and the second pressure threshold P2 th are adjusted 420 based on the determined at least one upcoming operation point, where the at least one upcoming operating point is determined based on one or more of information related to an upcoming usage of the vehicle 100 and
information related to a road section ahead of the vehicle.
The information related to the upcoming usage of the vehicle may, according to various embodiments, include external information, internal information, driver inputted
information, information provided by at least one other vehicle, information provided by at least one external
database, information provided by a tachograph, information related to a driving schedule, information related to a service schedule, and/or information related to a weight of the vehicle 100. The information may be provided by a driver of the vehicle, for example by a driver inputting a driving schedule, e.g. a bus line number, a delivery order number, and/or a freight/load weight.
The information may also be provided by internal systems, for example a system estimating the vehicle weight. In this document, the vehicle weight is defined as the total weight of the used vehicle combination, including possible trailers.
The information may also be provided by other vehicles
communicating with the vehicle 100, via so called vehicle-to- vehicle (V2V) communication, where the vehicles share
information with other vehicles. The information may also be provided by one or more infrastructure devices 170 (in figure 1), e.g. including one or more servers, databases and/or registers, via so called vehicle-to-infrastructure (V2I) communication, where the information may first have been collected by other vehicles, and may have been provided to the one or more infrastructure devices 170. The vehicle may thus include at least one communication device 160 (in figure 1), arranged for V2V communication, for V2I communication and/or for vehicle-to-everything (V2X) communication.
The upcoming usage of the vehicle may, according to an
embodiment, include a break and/or stop time period Tstop longer than a stop time threshold Tstop th/ e.g. a service or permanent break and/or stop. As mentioned above, there are in some regions rules stipulating how long a vehicle with an
essentially full tank should be able to be parked. If a break and/or stop time period Tstop longer than a stop time threshold Tstop th will come, the first pressure threshold Pi th may be reduced, such that the risk for having to open he safety valve 124 is reduced, since more gaseous state fuel 125 is then consumed. However, the first pressure threshold Pi th has to be high enough, i.e. equal to or above a minimum gas pressure threshold Pgas min/ in order for the system to be able to push the fuel out from tank 121.
The upcoming usage of the vehicle may, according to an
embodiment, include a number of breaks and/or stops Nst0p greater than a number threshold Nstop th/ Nstop > Nstop th · For example, for busses and/or garbage trucks having many stops, multiple stops and accelerations, and possibly also activation of garbage compression devices or the like at the stops, are common in the normal operation of some vehicles. Therefore, if a number of breaks and/or stops Nstop greater than a number threshold will come; Nstop > Nstop th then the first and/or second pressure threshold Pi th / P2 th may be reduced/increased.
The upcoming usage of the vehicle may, according to an
embodiment, also include a number of breaks and/or stops Nstop smaller than a number threshold Nstop th Nstop < Nstop th · For example, for long haulage vehicles, long stretches/distances are often travelled between the stops. Therefore, if a number of breaks and/or stops Nstop smaller than a number threshold will come; Nstop < Nstop th/ then the first and/or second pressure threshold Pi th / P2 th may be reduced/increased.
The upcoming usage of the vehicle may, according to an
embodiment, also include a usage resulting in an engine load Len greater than a load threshold Len th/ Len > Len th/ e.g. for a vehicle reaching an uphill road section and/or for a vehicle about to be accelerated. Therefore, if an engine load Len greater than a load threshold Len th; Len > Len th; will come, then the first and/or second pressure threshold Pi th / P2 th may be reduced/increased.
The upcoming usage of the vehicle may, according to an
embodiment, also include a usage resulting in an engine load Len smaller than a load threshold Len th/ Len < Len th/ e.g. for a vehicle reaching a downhill road section and/or for a vehicle about to decelerate. Therefore, if an engine load Len smaller than a load threshold Len th/ Len < Len th/ will come, then the first and/or second pressure threshold Pi th / P2 th may be reduced/increased .
The upcoming usage of the vehicle may, according to an
embodiment, also result in a vehicle weight W greater than a weight threshold Wth/ W > Wth/ e.g. when transporting heavy goods and/or material. Therefore, if a vehicle weight W greater than a weight threshold Wth/ W > Wth/ will come, then the first and/or second pressure threshold Pi th / P2 th may be reduced/increased .
The upcoming usage of the vehicle may, according to an
embodiment, also result in a vehicle weight W smaller than a weight threshold Wth/ W < Wth- Therefore, if a vehicle weight W smaller than a weight threshold Wth/ W < Wth/ will come, then the first and/or second pressure threshold Pi th / P2 th may be reduced/increased .
As mentioned above, the at least one upcoming operating point for the engine 101 may be determined 410 at least partly based on information related to a road section ahead of the vehicle, and the adjustment of one or more of the first and second pressure thresholds Pi th/ P2 th is then based on this determined operating point.
According to an embodiment, the information related to the road section ahead of the vehicle 100 may include information related to a speed limit for the road section, a topology of the road section, a curvature of the road section and/or a traffic situation within the road section. The first pressure threshold Pi th may for example be reduced if the upcoming road section includes a lower speed limit, a downhill stretch, one or more curves and/or slow moving traffic .
Correspondingly, the first pressure threshold Pi th may for example be increased if the upcoming road section includes a higher speed limit, an uphill stretch, one or more straight sections curves and/or fast moving, or no, traffic.
The second pressure threshold P2 th may be reduced and/or increased based on if the upcoming road section includes one or more uphill and/or downhill stretches, one or more curves, and/or one or more stretches with slow moving traffic and/or fast moving traffic.
The information related to the road section ahead of the vehicle 100 may e.g. be based on positioning information, map information, topology information, information provided by at least one other vehicle or at least one infrastructure device (V2V, V2I, V2X) 170, and/or information gathered by the vehicle 100 itself at an earlier point in time.
Thus, the determination of the operating point may, according to various embodiments of the present invention, be performed based also on information related to essentially any parameter being relevant for influencing and/or determining the behavior of the vehicle when travelling on the upcoming road section.
The information may for example be related vehicle positioning information, digital map information, topographical
information, curvature information, speed limit information, traffic information, radar-based information, camera-based information, requested vehicle speed information, other vehicle distance information, other vehicle speed information, vehicle weight information, information obtained from other vehicles than the vehicle 100, road information and/or
positioning information stored previously on board the vehicle 100, and/or information obtained from traffic systems related to that road section.
The information related to the upcoming road section may be obtained in various ways. It may be determined on the basis of map data, e.g. from digital maps including e.g. topographical information, in combination with positioning information, e.g. GPS (global positioning system) information. The positioning information may be used to determine the location of the vehicle relative to the map data so that the road section information may be extracted from the map data. Various present-day cruise control systems use map data and
positioning information. Such systems may then provide the system for the present invention with map data and positioning information, thereby minimizing the additional complexity involved in determining the road gradient.
The road section information may thus e.g. be obtained on the basis of a map in conjunction with GPS information. The information may also be obtained by usage of radar equipment, one or more cameras, one or more other vehicles providing information, information storing systems on board, and/or traffic systems related to the section of road.
The information may be used for performing simulations related to the vehicle 100 for the upcoming road section, such as e.g. on or more future speed profiles for the actual vehicle speed for the road section. The one or more simulations may
therefore be based on the current location of the vehicle and the current situation for the vehicle, and may virtually look ahead along the road section based on the information,
including e.g. the gradient for the road.
As a non-limiting example, the simulations may be conducted on board the vehicle at a predetermined rate, e.g. at a rate of 1 Hz, which means that a new simulation result is provided every second. The section of road for which the simulation is conducted represents a predetermined distance ahead of the vehicle, e.g. it might be 1 km long. The section of road may also be regarded as a horizon ahead of the vehicle, for which the simulation is to be conducted.
As is mentioned above, the maximal liquid torque Tmax nq is used in various embodiments of the present invention. The maximal liquid torque Tmax iiq may, according to an embodiment, be determined adaptively during normal operation of the vehicle, i.e. when the engine 101 runs. The determination of the maximal liquid torque Tmax nq is then based on a performance of the engine 101. For example, information related to the control of the fluid flows, i.e. control of the electrically controlled economizer 127, is stored and is utilized, together with the performance of the engine 101 resulting from the controlled flows, i.e. resulting from the control of the economizer, for the adaptive determination of the maximal liquid torque Tmax liq. A value of the maximal liquid torque Tmax iiq may here for example be actively adjusted, and
thereafter the maximal liquid torque Tmax iiq is adaptively determined based on that executed/performed active adjustment and on a performance of the engine 101 resulting from the active adjustment of the maximal liquid torque Tmax iiq. In other words, a change/adjustment of the maximal liquid torque Tmax iiq is here first actively effected, and thereafter the effect of this change/adjustment is analyzed. The analysis is then possibly followed by another adj ustment/change of the maximal liquid torque Tmax iiq, and so on.
According to an embodiment of the present invention, the maximal liquid torque Tmax nq is determined by running a test engine corresponding to the engine 101 used in the vehicle 100 on the liquid state fuel 126 in a test cell/laboratory
environment, and by measuring a resulting test torque Tuq test· The maximal liquid torque Tmax nq is then determined based on the test torque Tiiq test·
According to an embodiment, the maximal liquid torque Tmax nq is determined 410 by first determining a tendency for engine knocking when the fuel in the liquid state is provided to the engine, e.g. based on information provided by one or more knocking sensors, which may be acoustic sensors, arranged at the engine 101 and/or based on a knowledge of the octane number of the fuel provided to the engine. When the tendency for engine knocking has been determined, the maximal liquid torque Tmax iiq may be determined based on the determined
tendency, e.g. by, if knocking is detected, adjusting the ignition, and thereby also adjusting the providable torque, until the knocking stops. The maximal liquid torque Tmax liq is then determined as the torque providable without engine knocking occurring.
Correspondingly, the maximal gaseous torque Tmax gas is,
according to an embodiment, determined 410 by first
determining a tendency for engine knocking when the fuel in the gaseous state is provided to the engine, e.g. by usage of the above mentioned one or more knocking sensors and/or based on the octane number of the fuel provided to the engine. When the tendency for engine knocking has been determined, the gaseous liquid torque Tmax gas may be determined based on the determined tendency, by adjusting the ignition until the knocking stops, as mentioned above. The gaseous liquid torque Tmax gas is then determined as the torque providable without engine knocking occurring.
The determination of the maximal gaseous torque Tmax gas
providable by the engine 101 may be performed by running a test engine corresponding to the engine 101 in the vehicle 100 e.g. in a test cell/laboratory environment, and measuring a resulting maximal gaseous torque Tmax gas .
A person skilled in the art will appreciate that the
embodiments of the method for controlling a state of fuel provided from a fuel tank 121 to an engine 101, according to the present invention, may also be implemented in a computer program, which, when it is executed in a computer, instructs the computer to execute the method. The computer may be included in the herein described system and/or may be
coupled/connected to the herein described system. The computer program is usually constituted by a computer program product 603 stored on a non-transitory/non-volatile digital storage medium, in which the computer program is incorporated in the computer-readable medium of the computer program product. The computer-readable medium comprises a suitable memory, such as, for example: ROM (Read-Only Memory), PROM (Programmable Read- Only Memory) , EPROM (Erasable PROM) , Flash memory, EEPROM (Electrically Erasable PROM), a hard disk unit, etc.
Figure 6 shows in schematic representation a control
unit/system/means 600/140. The control unit/system/means
600/140 comprises a computing unit 601, which may be
constituted by essentially any suitable type of processor or microcomputer, for example a circuit for digital signal processing (Digital Signal Processor, DSP) , or a circuit having a predetermined specific function (Application Specific Integrated Circuit, ASIC) . The computing unit 601 is connected to a memory unit 602 arranged in the control unit/system/means 600/140, which memory unit provides the computing unit 601 with, for example, the stored program code and/or the stored data which the computing unit 601 requires to be able to perform computations. The computing unit 601 is also arranged to store partial or final results of computations in the memory unit 602.
In addition, the control unit/system/means 600/140 is provided with devices 611, 612, 613, 614 for receiving and transmitting input and output signals. These input and output signals may comprise waveforms, impulses, or other attributes which, by the devices 611, 613 for the reception of input signals, can be detected as information and can be converted into signals which can be processed by the computing unit 601. These signals are then made available to the computing unit 601. The devices 612, 614 for the transmission of output signals are arranged to convert signals received from the computing unit 601 in order to create output signals by, for example, modulating the signals, which can be transmitted to other parts of and/or systems within or outside the vehicle.
Each of the connections to the devices for receiving and transmitting input and output signals can be comprise one or more of a cable; a data bus, such as a CAN bus
(Controller Area Network bus), a MOST bus (Media Orientated Systems Transport bus), or some other bus configuration; or by a wireless connection. A person skilled in the art will appreciate that the above-stated computer can be constituted by the computing unit 601 and that the above-stated memory may be constituted by the memory unit 602. Control systems in modern vehicles commonly comprise
communication bus systems including one or more
communication buses for linking a number of electronic control units (ECU's), or controllers, and various components located on the vehicle. Such a control system may comprise a large number of control units/means and the responsibility for a specific function can be divided amongst more than one control unit/means. Vehicles of the shown type thus often comprise significantly more control units/means than are shown in figures 1, 2 and 6, which is well known to the person skilled in the art within this technical field.
In the shown embodiment, the present invention is implemented in the control unit/system/means 600/140. The invention can also, however, be implemented wholly or partially in one or more other control units/systems/means already present in the vehicle, or in some control unit/system/means dedicated to the present invention.
According to an aspect of the invention, a control unit 140 arranged for controlling a state of fuel provided from a fuel tank 121 to an engine 101 of a vehicle 100 is presented. As mentioned above, the fuel tank 121 stores fuel in gaseous 125 and liquid 126 state, and includes at least one gaseous fuel output conduit 122 and at least one liquid fuel output conduit 123.
The control unit 140 includes a determination unit/means 141, arranged for determining 410 at least one upcoming operating point for the engine 101 based on one or more of information related to an upcoming usage of a vehicle 100 including the engine 101 and the fuel tank 121, and information related to a road section ahead of the vehicle 100. The control unit 140 further includes adjustment unit/means 142, arranged for adjusting 420, based on the determined at least one upcoming operation point, one or more of a first pressure threshold Pi th and a second pressure threshold P2 th ·
As mentioned above, the first pressure threshold Pi th indicates a pressure below which only the fuel in liquid state 126 is provided to the engine 101, and the second pressure threshold P2 th indicates a pressure above which only the fuel in the gaseous state 125 is provided to the engine 101.
The control unit 140 also includes control unit/means 143, arranged for controlling 430 fuel flows through one or more of the at least one gaseous fuel output conduit 122 and the at least one liquid fuel output conduit 123 based on at least one or more of the first pressure threshold P2 th and the second pressure threshold P2 th ·
By activation of the above described determination unit/means 141, the adjustment unit/means 142, and the controlling unit/means 143, the above described method is performed, which has the above mentioned advantages.
Here and in this document, units/means are often described as being arranged for performing steps of the method according to the invention. This also includes that the units/means are designed to and/or configured to perform these method steps.
The at least one control unit 140 is in figures 1 and 2 illustrated as including separately illustrated units/means 141, 142, 143. Also, the control system/means 140 may include or be coupled to other control means/units, such as e.g. an engine control device/means, a clutch control unit, an exhaust treatment system control unit, and/or a gearbox control unit. These means/units/devices 141, 142, 143, 140 may, however, be at least to some extent logically separated but implemented in the same physical unit/device. These means/units/devices 141, 142, 143, 140 may also be part of a single logic unit which is implemented in at least two different physical units/devices. These means/units/devices 141, 142, 143, 140 may also be at least to some extent logically separated and implemented in at least two different physical means/units/devices. Further, these means/units/devices 141, 142, 143, 140 may be both logically and physically arranged together, i.e. be part of a single logic unit which is implemented in a single physical means/unit/device . These means/units/devices 141, 142, 143,
140 may for example correspond to groups of instructions, which can be in the form of programming code, that are input into, and are utilized by at least one processor when the units/means are active and/or are utilized for performing its method step, respectively. It should be noted that the control unit/means 140 may be implemented at least partly within the vehicle 100 and/or at least partly outside of the vehicle 100, e.g. in a server, computer, processor or the like located separately from the vehicle 100.
As mentioned above, the units 141, 142, 143 described above correspond to the claimed means 141, 142, 143 arranged for performing the embodiments of the present invention, and the present invention as such.
The control unit according to the present invention can be arranged for performing all of the above, in the claims, and in the herein described embodiments method steps. The control unit is hereby provided with the above described advantages for each respective embodiment.
A skilled person also realizes that the above described control unit may be modified according to the different embodiments of the method of the present invention. The present invention is also related to a vehicle 100, such as a truck, a bus or a car, including the herein described control unit 140.
The inventive method, and embodiments thereof, as described above, may at least in part be performed with/using/by at least one device. The inventive method, and embodiments thereof, as described above, may be performed at least in part with/using/by at least one device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof. A device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof may be one, or several, of a control unit, an electronic control unit (ECU) , an electronic circuit, a computer, a computing unit and/or a processing unit .
With reference to the above, the inventive method, and
embodiments thereof, as described above, may be referred to as an, at least in part, computerized method. The method being, at least in part, computerized meaning that it is performed at least in part with/using/by the at least one device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof.
With reference to the above, the inventive method, and
embodiments thereof, as described above, may be referred to as an, at least in part, automated method. The method being, at least in part, automated meaning that it is performed
with/using/by the at least one device that is suitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof.
The present invention is not limited to the above described embodiments. Instead, the present invention relates to, and encompasses all different embodiments being included within the scope of the independent claims.

Claims

Claims
1. A method (400) for controlling a state of fuel provided from a fuel tank (121) to an engine (101), said fuel tank (121) storing fuel in gaseous (125) and liquid (126) state, and including at least one gaseous fuel output conduit (122) and at least one liquid fuel output conduit (123);
characterized by
- determining (410) at least one upcoming operating point for said engine (101) based on one or more of information related to an upcoming usage of a vehicle (100) including said engine (101) and said fuel tank (121), and information related to a road section ahead of said vehicle (100);
- adjusting (420), based on the determined at least one upcoming operation point, one or more of a first pressure threshold Pi th for the fuel tank and a second pressure
threshold P2 th for the fuel tank wherein said first pressure threshold Pi th indicates a pressure below which only said fuel in liquid state (126) is provided to said engine (101), and said second pressure threshold P2 th indicates a pressure above which only said fuel in said gaseous state (125) is provided to said engine (101); and
- controlling (430) fuel flows through one or more of said at least one gaseous fuel output conduit (122) and said at least one liquid fuel output conduit (123) based on at least one or more of said first pressure threshold P2 th and said second pressure threshold P2 th ·
2. The method (400) as claimed in claim 1, wherein said adjusting (420) of one or more of said first pressure
threshold P2 th and said second pressure threshold P2 th is performed such that an amount of said fuel in said gaseous state (125) needed for said engine (101) to reach said at least one upcoming operating point is available in said tank (121) .
3. The method (400) as claimed in any one of claims 1-2, wherein said information related to said upcoming usage includes one or more of:
- external information;
- internal information;
- driver inputted information;
- information provided by at least one other vehicle;
- information provided by at least one external database;
- information provided by a tachograph;
- information related to a driving schedule;
- information related to a loading schedule;
- information related to a service schedule; and
- information related to a weight of said vehicle (100) .
4. The method (400) as claimed in any one of claims 1-3, wherein said upcoming usage includes one or more of:
- a permanent break and/or stop;
- a break and/or stop time period Tstop longer than a stop time threshold Tstop-th;
- a number of breaks and/or stops Nstop greater than a number threshold, fbtoP ^ b/toP th^
- a number of breaks and/or stops Nstop smaller than a number threshold, fbtoP ^ b/toP th^
- a usage resulting in an engine load Len greater than a load threshold Len th ben ^ ben th
- a usage resulting in an engine load Len smaller than a load threshold Len th ben ^ ben th
- a usage resulting in a vehicle weight W greater than a weight threshold Wth/ W > Wth/ and
- a usage resulting in a vehicle weight W smaller than a weight threshold Wth/ W < Wth-
5. The method (400) as claimed in any one of claims 1-4, wherein said information related to said road section ahead of said vehicle (100) includes one or more of:
- a speed limit for said road section;
- a topology of said road section;
- a curvature of said road section; and
- a traffic situation within said road section.
6. The method (400) as claimed in any one of claims 1-5, wherein said information related to said road section ahead of said vehicle (100) is based on one or more of:
- positioning information;
- map information;
- topology information;
- information provided by at least one other vehicle;
- information provided by at least one infrastructure device; and
- information gathered by said vehicle (100) at an earlier point in time.
7. The method (400) as claimed in any one of claims 1-6, wherein said controlling (430) of said fuel flows through one or more of said at least one gaseous fuel output conduit (122) and said at least one liquid fuel output conduit (123) is performed such that only said fuel in said gaseous state (125) is provided to said engine (101) if a gaseous pressure Pgas of said gaseous state fuel (125) is greater than said second pressure threshold P2 th! Pgas > P2 th ·
8. The method (400) as claimed in any one of claims 1-7, wherein said controlling (430) of said fuel flows through one or more of said at least one gaseous fuel output conduit (122) and said at least one liquid fuel output conduit (123) is performed such that only said fuel in said liquid state (126) is provided to said engine (101) if a gaseous pressure Pgas of said gaseous state fuel (125) is smaller than said first pressure threshold Pith/ Pgas < Pith·
9. The method (400) as claimed in any one of claims 1-8, wherein said controlling (430) of said fuel flows through one or more of said at least one gaseous fuel output conduit (122) and said at least one liquid fuel output conduit (123) is based on a requested engine torque Treq if a gaseous pressure Pgas of said gaseous state fuel (125) is greater than said first pressure threshold Pi th and smaller than said second pressure threshold P2 th ; Pi th < Pgas < P2 th ·
10. The method (400) as claimed in any one of claims 1-9, wherein said adjusting (420) of said first pressure threshold Pi th results in a value of said first pressure threshold Pi th being greater than a minimum first pressure threshold value
Pi th min / said minimum first pressure threshold value Pi th min being related to a capability of said fuel tank (121) to provide said fuel flows through one or more of said at least one gaseous fuel output conduit (122) and said at least one liquid fuel output conduit (123) .
11. The method (400) as claimed in any one of claims 1- 10, wherein said adjusting (420) of said second pressure threshold P2 th results in a value of said second pressure threshold P2 th being smaller than a maximum second pressure threshold value P2 th max/ said maximum second pressure threshold value P2 th max being related to a maximally allowed pressure
Pgas max for said fuel tank (121) .
12. The method (400) as claimed in any one of claims 1- 11, wherein said fuel in said gaseous state (125) has a higher octane number than said fuel in said liquid state (126) .
13. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any one of claims 1-12.
14. A computer-readable medium comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any one of claims 1-12.
15. A control unit (140) arranged for controlling a state of fuel provided from a fuel tank (121) to an engine (101), said fuel tank (121) storing fuel in gaseous (125) and liquid (126) state, and including at least one gaseous fuel output conduit (122) and at least one liquid fuel output conduit
(123); characterized by
- means (141) arranged for determining (410) at least one upcoming operating point for said engine (101) based on one or more of information related to an upcoming usage of a vehicle (100) including said engine (101) and said fuel tank (121), and information related to a road section ahead of said
vehicle (100) ;
- means (142) arranged for adjusting (420), based on the determined at least one upcoming operation point, one or more of a first pressure threshold Pi th for the fuel tank and a second pressure threshold P2 th for the fuel tank, wherein said first pressure threshold Pi th indicates a pressure below which only said fuel in liquid state (126) is provided to said engine (101), and said second pressure threshold P2 th indicates a pressure above which only said fuel in said gaseous state (125) is provided to said engine (101); and
- means (143) arranged for controlling (430) fuel flows through one or more of said at least one gaseous fuel output conduit (122) and said at least one liquid fuel output conduit (123) based on at least one or more of said first pressure threshold Pi th and said second pressure threshold P2 th ·
PCT/SE2019/050498 2018-06-04 2019-05-29 Method and control unit for controlling a state of fuel provided to an engine WO2019235993A1 (en)

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US20170184056A1 (en) * 2011-12-22 2017-06-29 Westport Power Inc. Method And Apparatus For Supplying A Gaseous Fuel To An Internal Combustion Engine
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