SE1850671A1

SE1850671A1 - Method and system for controlling a state of fuel provided to an engine

Info

Publication number: SE1850671A1
Application number: SE1850671A
Authority: SE
Inventors: Erik Sunnegårdh; Magnus Johansson
Original assignee: Scania Cv Ab
Priority date: 2018-06-04
Filing date: 2018-06-04
Publication date: 2019-12-05
Also published as: WO2019235993A1; SE542897C2

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, based on the determined at least one upcoming operation point, one or more of a first pressure threshold Pand a second pressure threshold P, wherein said first pressure threshold Pindicates a pressure below which only said fuel in liquid state is provided to said engine, and said second pressure threshold Pindicates 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 at least one gaseous fuel output conduit and said at least one liquid fuel output conduit based on at least one or more of said first pressure threshold Pand said second pressure threshold P.

Description

lO METHOD AND SYSTEM FOR CONTROLLING A STATE OF FUEL PROVIDED TOAN ENGINE Field of invention The present invention relates to a method for controlling astate of fuel provided from a fuel tank to an engine, asdefined in the preamble of claim l. The present invention alsorelates to a control unit arranged for controlling a state offuel provided from a fuel tank to an engine, as defined in thepreamble of claim 15. The present invention also relates to acomputer program and a computer-readable medium comprisinginstructions for carrying out the method according to the invention.

Background of invention The following background information is a description of thebackground 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, aredriven forward by an engine torque produced by an engine inthe vehicle. This engine torque is provided to the drivingwheels of the vehicle through a powertrain. The torque may becreated at least partly in a combustion engine by combustionof 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 exampleinclude liquified natural gas (LNG). Such liquified naturalgas (LNG) is often stored in at least one pressurized fueltank. In the tank, fuel in gaseous and liquid state is stored.The pressurized fuel tank includes a gaseous fuel outputconduit in contact with the gaseous state fuel, and a liquidfuel output conduit in contact with the liquid state fuel.

Thus, liquid state fuel may be provided to the engine through lO the liquid fuel output conduit, and gaseous state fuel may beprovided to the engine through the gaseous fuel output conduit.

The pressure Pgæ of the gaseous state fuel is used as, or isat least related to, a drive pressure Püiw utilized forpushing the fuel out from the pressurized tank, i.e. utilizedfor driving the fuel out through the liquid or gaseous fueloutput conduits. Therefore, the pressure Pgæ of the gaseousstate fuel has to be high enough, i.e. above a minimum gaspressure threshold Pgægmn, in order to be able to push the fuelout from tank. However, in order to prevent the pressurizedtank from exploding, the pressure Pgæ of the gaseous fuel maynot be allowed to increase above a maximal gas pressurethreshold Pgægmx, which for example may have a value in theregion of 20 bar. A safety valve may be arranged for openingthe valve when the gaseous pressures Pgæ reaches the maximalgas pressure threshold Pgæamx, thereby letting gaseous statefuel pass out to the ambient air in order to reduce the gaseous pressure Pgæ.

Generally, the gaseous state fuel has a higher octanenumber/rating than the liquid state fuel has, since thelighter hydrocarbons are evaporated from the liquid state fuelwhen the gaseous state fuel is created. The liquid state fuelincludes a mixture of various hydrocarbons providing a loweroctane number/rating than the evaporated lighter hydrocarbons in the gaseous state fuel result in.

However, gaseous state fuel takes up a much greater volumethan liquid state fuel due to its much lower density.Therefore, the pressurized fuel tank should at least partlyinclude fuel in liquid form in order to provide an acceptable reach/range for a vehicle comprising the tank and the engine. lO The differing octane numbers/ratings for the gaseous andliquid states of the fuel may be used such that the liquidstate fuel is used under some conditions and that the gaseousstate fuel is used under other conditions. For example, thegaseous state fuel may be used when a higher torque isrequested, e.g. for acceleration or uphill driving. To achievethis, a mechanical economizer has in conventional solutionsbeen arranged to switch between supplying liquid state fueland gaseous state fuel to the engine. Such a mechanicaleconomizer has e.g. been arranged as a mechanical switch,which is able to switch between connecting the gaseous fueloutput conduit of the tank to the engine and connecting the liquid fuel output conduit to the engine.

SUMARY OF INVENTION The mechanical economizer used in conventional solutions isarranged to switch between providing liquid and gaseous statefuel to the engine at a gas pressure Pgæ corresponding to apredetermined switch threshold Pgæiwum of the gaseous statefuel, often having a value corresponding to a gas pressure Pgﬂof l2 bar; Pgæ = l2 bar. For example, if the gas pressure Pgæof the gaseous state fuel is increased above the switchthr@ShOld Pgﬂ_w¿m, the economizer switches to provide onlygaseous state fuel to the engine. Correspondingly, if the gaspressure Pgæ of the gaseous state fuel is decreased below theswitch threshold Pgæiwum, the economizer switches to provide only liquid state fuel to the engine.

However, due to component individual variations, differentmechanical economizer individuals may switch at differentgaseous pressures Pgﬂ, although they are all designed toswitch at the threshold Pgﬂ_w¿m. Thus, different mechanical economizer individuals may provide different states lO (gaseous/fluid) of the fuel to its respective engines at the same gaseous Pgﬂ.

The state of the fuel being provided to the engine has aninfluence on the pressure Pgæ of the gaseous fuel, andtherefore has an influence on the drive pressure Püiw used forpushing the fuel to the engine. Generally, if gaseous statefuel is provided to the engine, the pressure Pgæ of the gaseous fuel is decreased.

Further, the component individual variations may also resultin an unreliable control of the state of fuel being providedto the engine. There is therefore a risk that engine knockingmight occur, since the octane number/rate of the fuel providedto the engine is not reliably controlled. Thus, theuncertainty of the conventionally used mechanical economizermay cause engine control difficulties. Tf it cannot beguaranteed that there is enough gaseous state fuel availablefor combustion in the engine there is a risk that the engineis not able to provide a torque Tnﬂ being requested. This mayby 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 forcontrolling a state of fuel provided from a fuel tank to anengine, the fuel tank storing fuel in gaseous and liquidstate, and including at least one gaseous fuel output conduitand at least one liquid fuel output conduit according to thecharacterizing portion of claim l, the method including: - determining at least one upcoming operating point for theengine based on one or more of information related to anupcoming usage of a vehicle including the engine and the fuel tank, and information related to a road section ahead of the lO vehicle; - adjusting, based on the determined at least one upcomingoperation point, one or more of a first pressure threshold Pyihand a second pressure threshold P¿¿h, wherein the firstpressure threshold Pyih indicates a pressure below which onlythe fuel in liquid state is provided to the engine, and thesecond pressure threshold P¿¿h indicates a pressure above whichonly the fuel in the gaseous state is provided to the engine;and - controlling fuel flows through one or more of the at leastone gaseous fuel output conduit and the at least one liquidfuel output conduit based on at least one or more of the first pressure threshold Prih and the second pressure threshold Piih.

Hereby, an increased flexibility for the control of the state of fuel being provided to the engine is achieved. The state offuel and/or the mixture/ratio of states of fuel being providedto 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 Pyihand the second pressure threshold P¿;h, a pressure intervalPL¿h - P¿¿h is also adjusted. This pressure interval Pyih - P¿¿hmay then be intelligently utilized for matching the upcomingusage of the vehicle with a suitable state of fuel. Thus, thegaseous state fuel, having a higher octane number/rate, may bestored for known upcoming in situations when it is reallyneeded, i.e. in situations when a requested engine torque Tnnis so high that it cannot be provided by combustion of liquid state fuel.

Thus, a pressure region/interval PL¿h - P¿¿h between the firstpressure threshold Prﬂh and the second pressure threshold P¿¿h is defined, adjusted and/or used by some embodiments of the lO present invention. This pressure region PL¿h - P¿¿h does noteven exist for a conventional mechanical economizer, since theconventional mechanical economizer switches only based on thepressure. The pressure region PL;h - P¿;h created by theembodiments of the present invention may be utilized forcontrolling the electronic controllable economizer e.g. inrelation to an upcoming requested engine torque Tnﬂ. Hereby, amore 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 tooptimize the state of fuel and/or the ratio between gaseousand 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 andaccurate control of the controllable electronic economizer,which enables that higher torques may be provided by theengine when needed, since more gaseous state fuel (havinghigher octane number/rate) will be available for being provided to the engine when needed.

According to an embodiment of the present invention, theadjusting of one or more of the first pressure threshold Pyihand the second pressure threshold P¿¿h is performed such thatan amount of fuel in the gaseous state needed for the engineto reach the at least one upcoming operating point is available in the tank.

Hereby, it is secured that the higher octane number/rategaseous 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 lO 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 operatingpoint for the engine may be based on one or more of a largenumber of different information, a reliable and accurate determination can be made in any situation.

According to an embodiment of the present invention, theupcoming usage includes one or more of: - a permanent break and/or stop; - a break and/or stop time period Tgum longer than a stop timethreshold Tumpmh; - a number of breaks and/or stops Nuxm greater than a numberthreshold; Ngum > Numpmh; - a number of breaks and/or stops Ngum smaller than a numberthreshold; Ngum > Numpmh; - a usage resulting in an engine load Lulgreater than a loadthreshold Lemih; Leg > Lgumh; - a usage resulting in an engine load Lulsmaller than a loadthreshold Lemih; Leg < Lgumh; - a usage resulting in a vehicle weight W greater than aweight threshold Ww; W > Wuﬁ and - a usage resulting in a vehicle weight W smaller than a lO weight threshold Ww; W < Wap Hereby, the determination of the at least one upcomingoperating point for the engine may be reliably and accurately determined.

According to an embodiment of the present invention, theinformation related to the road section ahead of the vehicleincludes 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 upcomingoperating point for the engine may be reliably and accurately determined.

According to an embodiment of the present invention, theinformation related to the road section ahead of the vehicleis 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 upcomingoperating point for the engine may be reliably and accurately determined. lO According to an embodiment of the present invention, thecontrolling of the fuel flows through one or more of the atleast one gaseous fuel output conduit and the at least oneliquid fuel output conduit is performed such that only thefuel in the gaseous state is provided to the engine if agaseous pressure Pgæ of the gaseous state fuel is greater than the second pressure threshold P¿¿h; Pﬁß > P¿;h.

Hereby, the risk for having to open the safety valve isreduced, whereby also a reduction of the fuel consumption is achieved over time.

According to an embodiment of the present invention, thecontrolling of the fuel flows through one or more of the atleast one gaseous fuel output conduit and the at least oneliquid fuel output conduit is performed such that only thefuel in the liquid state is provided to the engine if agaseous pressure Pgæ of the gaseous state fuel is smaller than the first pressure threshold Pi;h; Fgﬂ < Prih.

Hereby, is it secured that the gas pressure Pgæ is high enoughfor being able to push the fuel out from the tank, and to theengine, i.e. that a high enough drive pressure P@¿W is available.

According to an embodiment of the present invention, thecontrolling of the fuel flows through one or more of the atleast one gaseous fuel output conduit and the at least oneliquid fuel output conduit is based on a requested enginetorque Tnﬁ if a gaseous pressure Pgﬂ of the gaseous state fuelis greater than the first pressure threshold P;;h and smaller than the second pressure threshold Pgih; Pyih < Pgæ < Pgih.

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 Tnﬂ. The engine is then provided withthe fuel it needs to provide the requested torque Tag, at thesame 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, theadjusting of the first pressure threshold Pyih results in avalue of the first pressure threshold PL;h being greater than aminimum first pressure threshold value Priwﬂnw the minimumfirst pressure threshold value Priwmm being related to acapability of the fuel tank to provide the fuel flows throughone 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 Pgæ is high enoughfor being able to push the fuel out from the tank, and to the engine.

According to an embodiment of the present invention, theadjusting of the second pressure threshold P¿¿h results in avalue of the second pressure threshold P¿;h being smaller thana maximum second pressure threshold value P¿;@mw, the maximumsecond pressure threshold value P¿;@mﬂ being related to a maximally allowed pressure Pgægmx for the fuel tank.

Hereby, the risk for wasting fuel due to opening of the safetyvalve is reduced, since the second pressure threshold P¿¿h isdetermined in relation to the maximally allowed pressure Pgægmxfor the tank, i.e. in relation to a safety valve releasepressure. For example, the herein described second pressurethreshold P¿¿h may, according to an embodiment, be equal to themaximally allowed pressure Pgægmx for the tank minus a safety Ûffset Pgas_offset/° P2_th I Pgas_max _ Pgas_offset/° Where the safety lO ll offset Pgæ_ﬁf¶m has a value providing a reasonable margin tothe safety valve release pressure, i.e. to the maximally allowed pressure Pgægmx.

According to an embodiment of the present invention, the fuelin the gaseous state has a higher octane number than the fuel in the liquid state.

The recognition of the various octane numbers/rates forvarious fuel states is utilized by the embodiments of the present invention.

The object is also achieved by the above mentioned controlunit arranged for controlling a state of fuel provided from afuel tank to an engine, the fuel tank storing fuel in gaseousand liquid state, and including at least one gaseous fueloutput conduit and at least one liquid fuel output conduit,according to the characterizing portion of claim l5. Thecontrol unit includes: - means arranged for determining at least one upcomingoperating point for the engine based on one or more ofinformation related to an upcoming usage of a vehicleincluding the engine and the fuel tank, and informationrelated to a road section ahead of the vehicle; - means arranged for adjusting, based on the determined atleast one upcoming operation point, one or more of a firstpressure threshold Prﬂh and a second pressure threshold P¿¿mwherein the first pressure threshold Pyih indicates a pressurebelow which only the fuel in liquid state is provided to theengine, and the second pressure threshold P¿¿h indicates apressure above which only the fuel in the gaseous state isprovided 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 lO l2 at least one liquid fuel output conduit based on at least oneor more of the first pressure threshold Prih and the second pressure threshold Pgih.

The control unit has the same advantages as stated above for the method.

According to an embodiment of the present invention, theadjusting means is arranged for performing the adjusting ofone or more of the first pressure threshold P;;h and the secondpressure threshold Pgﬂh such that an amount of the fuel in thegaseous 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, theinformation related to the upcoming usage includes one or moreof: - 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, theupcoming usage includes one or more of: - a permanent break and/or stop; - a break and/or stop time period TSUW longer than a stop timethreshold Taßpih; - a number of breaks and/or stops Naxs greater than a number threshold; Ngum > Naßpih; lO l3 - a number of breaks and/or stops Ngum smaller than a numberthreshold; Ngum > Naßpih; - a usage resulting in an engine load Lﬁlgreater than a loadthreshold Lemih; Lem > Lemih; - a usage resulting in an engine load Lﬂlsmaller than a loadthreshold Lemih; Lem < Lemih; - a usage resulting in a vehicle weight W greater than aweight threshold Ww; W > Waﬁ and - a usage resulting in a vehicle weight W smaller than a weight threshold Ww; W < Wap According to an embodiment of the present invention, theinformation related to the road section ahead of the vehicleincludes 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, thecontrol means is arranged for performing the control of the fuel flows through one or more of the at least one gaseous 14 fuel output conduit and the at least one liquid fuel outputconduit such that only the fuel in the gaseous state isprovided to the engine if a gaseous pressure Pgæ of thegaseous state fuel is greater than the second pressure thlfêshOld P2/thí ägas > Pgfth.

According to an embodiment of the present invention, thecontrol means is arranged for performing the control of thefuel flows through one or more of the at least one gaseousfuel output conduit and the at least one liquid fuel outputconduit such that only the fuel in the liquid state isprovided to the engine if a gaseous pressure Pgæ of thegaseous state fuel is smaller than the first pressure threshold Priní Pgß < PL;h.

According to an embodiment of the present invention, thecontrol means is arranged for performing the control of thefuel flows through one or more of the at least one gaseousfuel output conduit and the at least one liquid fuel outputconduit is based on a requested engine torque Tnﬁ if a gaseouspressure Pgæ of the gaseous state fuel is greater than thefirst pressure threshold Prﬂh and smaller than the second pressure threshold Pgih; Prih < Pqß < P¿¿h.

According to an embodiment of the present invention, theadjustment means is arranged for adjusting the first pressurethreshold PL;h such that it results in a value of the firstpressure threshold Pi;h being greater than a minimum firstpressure threshold value Priwﬂnu the minimum first pressurethreshold value Priwmm being related to a capability of thefuel tank to provide the fuel flows through one or more of theat least one gaseous fuel output conduit and the at least one liquid fuel output conduit.

According to an embodiment of the present invention, theadjustment means is arranged for adjusting the second pressurethreshold P¿;h such that it results in a value of the secondpressure threshold P¿;h being smaller than a maximum secondpressure threshold value P¿;@mﬂ, the maximum second pressurethreshold value Pxlmmﬂ being related to a maximally allowed pressure Pgægmx for the fuel tank.

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 mediumaccording to the invention will below be described withreference to the appended drawings illustrating some preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention are described in more detail withreference to attached drawings illustrating examples of embodi- ments of the invention in which: Figure l is a schematic illustration of a non-limiting exampleof a vehicle in which the embodiments of the present invention may be implemented, Figure 2 is a schematic illustration of a fuel providingsystem, in which the embodiments of the present invention may be implemented, 16 Figures 3a-b show a conventional economizer and valves thatmay 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 regionsand 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 atruck, a bus, a car, or another suitable vehicle, which willbe used to explain the present invention. The presentinvention is, however, not limited to use in heavy goodsvehicles as the one shown in figure 1, but may also be used inessentially any vehicle, such as lighter vehicles, e.g. passenger cars.

The vehicle 100, shown schematically in figure 1, comprises anengine 101, which may comprise a combustion engine, e.g. anengine consuming liquified natural gas (LNG), in order tocreate a torque being provided for driving the vehicle, e.g. adiesel engine, or an engine working according to the Ottocycle for which an electric spark ignites a fuel and airmixture in the engine cylinders, e.g. a gasoline or ethanolengine. Essentially, the engine 101 may in this documentcomprise any device which transforms chemical energy tomechanical energy, and uses gaseous and liquid state fuel forits combustion/energy transformation. The engine then provides energy in form of a torque to the powertrain. Exhaust gases 17 produced by the engine 101 are purified by an exhausttreatment 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, viaan output shaft 102 of the engine 101, be connected with agearbox 103, via a clutch 106 and an input shaft 109 connectedto the gearbox 103. An output shaft 107 from the gearbox 103,also known as a propeller shaft, drives the driving wheels110, 111 via a final gear 108, such as e.g. a customarydifferential, and drive shafts 104, 105 connected with the final gear 108.

A fuel providing system 120, including at least one fuel tank121, which may be pressurized, is arranged for providing theengine 101 with fuel. The fuel providing system 120 is described more in detail below.

A control unit 140 is in figure 1 schematically illustrated asreceiving signals and/or providing control signals from and/orto the engine 101 and/or the pressurized fuel tank 121. Thecontrol unit 140 may also receive and/or provide controlsignals to and/or from other devices in the vehicle 100.According to some embodiments of the present invention, asdescribed in this document, the control unit 140 may alsocomprise determining means 141, e.g. a determination unit 141,adjusting means 142, e.g. an adjustment unit 142, and controlmeans 143, e.g. a control unit 143. These controlmeans/units/devices 141, 142, 143 are described more in detailbelow, and may be divided physically into more than the hereindescribed 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 18 example include gaseous 125 and liquid 126 state fuel, such ase.g. states of a liquified natural gas (LNG). Such gaseous andliquid state fuel is stored in a fuel tank 121, which often isa pressurized fuel tank. The fuel tank includes a gaseous fueloutput conduit 122 in contact with the gaseous state fuel 125,and a liquid fuel output conduit 123 in contact with theliquid state fuel 126. Liquid state fuel 126 may therefore beprovided to the engine through the liquid fuel output conduit123, and gaseous state fuel 125 may be provided to the enginethrough the gaseous fuel output conduit 122. The tank 121 mayinclude the above mentioned safety valve 124 arranged foropening the valve 124 if the gaseous pressures Pgﬂ reaches themaximal gas pressure threshold Pgægmx. Hereby, the gaseousstate fuel is allowed to pass out into the ambient air outsideof the system/vehicle, which efficiently limits and/or reduces the gaseous pressure Pgﬂ.

Conventional fuel providing systems 120 have been equippedwith the above mentioned mechanical economizer, schematicallyillustrated in figure 3a, arranged to switch betweenconnecting either the gaseous fuel output conduit 122 or theliquid fuel output conduit 123 to the engine, e.g. via a fuelarrangement 128, such as pipe and/or a tube. The conventionalmechanical economizer has the above mentioned drawbacks/disadvantages.

The present invention, and its embodiments, may insteadutilize an electronically controlled economizer 127schematically illustrated in figure 3b. The electronicallycontrolled economizer 127 includes at least one controllablevalve 129 arranged in at least one of the gaseous fuel outputconduit 122 and the liquid fuel output conduit 123. Forexample, one such electronically controllable valve 129 may be arranged at each one of the the gaseous fuel output conduit 19 122 and the liquid fuel output conduit 123. By usage of theelectronically controlled economizer 127, the portions/ratiosof gaseous 125 and liquid 126 state fuel to be provide to theengine, e.g. via a fuel arrangement 128, may easily beachieved. Thus, by usage of the electronically controlledeconomizer 127, it is not only possible to choose to provideeither gaseous or liquid state fuel to the engine (as for theconventional mechanical economizer in figure 3a). Instead, itis possible to control the controllable at least one valve 129of the electronically controlled economizer 127 such thatessentially any combination/mixture of gaseous 125 and liquid126 state fuel is provided to the engine. Thus, essentiallyany ratio of gaseous 125 and liquid 126 fuel, and thereforealso any variety of possible octane numbers/rates, may herebybe 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 accordingto an embodiment of the present invention, i.e. a method forcontrolling a state of fuel provided from a fuel tank 121 toan engine 101, wherein the fuel tank 121 is storing fuel ingaseous 125 and liquid 126 state. The tank 121 includes atleast 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 orderthan the order illustrated in figure 4, as long as theinformation 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 abelow described determination unit/means 141, at least oneupcoming 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 fueltank 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 abelow described adjustment unit/means 142, one or more of afirst pressure threshold P;;h and a second pressure thresholdP¿;h are adjusted based on the determined at least one upcomingoperation point. The first pressure threshold Pyﬂh indicates apressure below which only fuel in liquid state 126 is to beprovided to the engine 101. The second pressure threshold P¿¿hindicates 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 abelow described control unit/means 143, fuel flows through oneor more of the at least one gaseous fuel output conduit 122and the at least one liquid fuel output conduit 123 iscontrolled based on at least one or more of the first pressurethreshold Prﬂh and the second pressure threshold Pgih. Asmentioned above, the control of the fuel flows may includecontrol of at least one controllable valve 129 arranged in atleast one of the gaseous fuel output conduit 122 and the liquid fuel output conduit 123.

By usage of the present invention, an increased flexibilityfor the control of the state of fuel being provided to theengine is achieved. The state of fuel and/or the mixture ofstates of fuel being provided to the engine may be tailoredsuch 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 Pyihand the second pressure threshold P¿;h based on the determined at least one upcoming operation point, a pressure interval Pyih 21 - Pglh between the first pressure threshold Prih and the secondpressure threshold Pgih is adjusted, as is illustrated infigure 5a. The first pressure threshold Pijh may here beadjusted within a region defined by a minimum Priwmm and amaximum PL¿@mﬂ value; PL¿@ﬂn1< Pyih < PL¿@mﬂ. For example, theminimum first pressure threshold Priwmm may, according to anembodiment, be equal to the pressure Pgægmﬂ needed forproviding the fuel flows through one or more of the at leastone gaseous fuel output conduit and the at least one liquidfuel output conduit. The second pressure threshold P¿¿h maycorrespondingly be adjusted within a region defined by aminimum Pxiwmm and a maximum P¿¿@mﬂ value; P¿¿@mn1< Pgih 5a.

Then when adjusting the first pressure threshold Prlh and/orthe second pressure threshold P¿;h, the resulting thresholdvalues should be within suitable regions/ranges, asillustrated in figure 5a. For example, the adjusted firstpressure threshold value Pi;h should be greater than a minimumfirst pressure threshold value Priwmm, which is related to acapability of the fuel tank 121 to provide the fuel flowsthrough one or more of the at least one gaseous fuel outputconduit 122 and the at least one liquid fuel output conduit123, as mentioned above. Also, the adjusted second pressurethreshold value P¿;h should for example be smaller than amaximum second pressure threshold value P¿¿@mﬂ, which isrelated to a maximally allowed pressure Pgæjmx for the fueltank 121. Basically, the second pressure threshold P¿¿hindicates a pressure over which the gaseous state fuel in thetank 121 needs to be reduced in order to avoid the gas pressure Pgæ reaching a maximally allowed pressure Pgæjmx for 22 the tank, thereby triggering an opening of the safety valve 124, which would waste valuable gaseous state fuel.

Within the pressure interval PL;h - Pgih, the state of the fuelprovided to the engine may be intelligently/flexibly chosenbased on one or more parameters. One such example isillustrated in figure 5b, wherein the requested torque Tmq,which could be either a currently requested torque or a torquethat will be requested during an upcoming road section, isused as a parameter. For example, the fuel flows through oneor more of the at least one gaseous fuel output conduit 122and the at least one liquid fuel output conduit 123 may becontrolled such that the fuel provided to the engine 101includes a majority, i.e. > 50%, of the fuel in the liquidstate 126 if the requested engine torque Tnﬂ is lower than orequal to a maximal liquid torque Tmﬂyuq; Tmg S Tmﬂyuq. However,if requested engine torque Tnﬂ is higher than the maximalliquid tOrqu@ Tmﬂbuq; Tmq > Tmﬂynq; the fuel flows through oneor more of the at least one gaseous fuel output conduit 122and the at least one liquid fuel output conduit 123 arecontrolled such that only the fuel in the gaseous state 125 is provided to the engine 101 The first pressure threshold PL¿h may here be related to, e.g.may according to an embodiment be as low ascorresponding/equal to, the above mentioned minimum gaspressure Pgﬂgmn needed for pushing the fuel out from the tank121; PL;h= Pgﬂamn, and may as a non-limiting example have avalue corresponding to a gas pressure Pgæ of 10 bar; Pgæ = 10bar. The second pressure threshold P2_th may indicate apressure over which an amount of the gaseous state fuel 125 inthe tank 121 needs to be reduced in order to avoid that thepressure Pga of the gaseous state fuel 125 reaches the maximally allowed pressure Pgægmx for the tank, which would 23 trigger an opening of the safety valve 124. Thus, the secondpressure threshold P¿¿h is related to the maximally allowed gaspressure Pgægmx for the tank 121, and may as a non-limitingexample correspond to a gas pressure Pgæ of 18 bar; Pgæ = 18 bar.

According to an embodiment of the present invention, when thegas pressure Pgæ is within the above mentioned pressureinterval PL¿h - P¿¿h, various levels of requested torque resultin various fuel state mixtures, such as 100 % fuel in thegaseous state, a mixture of the fuel in the gaseous state andin the liquid state, or 100% fuel in the liquid state. Thus,the control 430 of the fuel flows through one or more of theat 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 Tmq.

A couple of non-limiting examples of fuel statemixtures/ratios are given in the following. One or more ofsuch examples mixtures/ratios may, according to an embodimentof the present invention, be utilized as initial values forone or more of the embodiments of fuel state control described in this document.

According to a control algorithm, if the requested enginetorque TNQ is higher than the maximal liquid torque Tmﬂyuq; Tmq> Tmﬂ_nq; 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 enginetorque Tug is lower than or equal to the maximal liquid torqueTmﬂtuq; Tmq 3 Tmﬂyuq; then 100% fuel in liquid state 126, i.e.0% fuel in gaseous state 125, may be provided to the engine 101. 24 According to a control algorithm, if the requested enginetorque Tnﬂ is higher than 110% of the maximal liquid torqueTmﬂyuq; Tmq > 1.1*Tmﬂ;uq; 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 enginetorque Tnﬂ is in an interval between 80% and 110% of themaximal liquid torque Tmaxgiq; 0.8*Tmax_liq < Treq < 1.1*TmaX_1iq;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 enginetorque Tug is higher than 90% of the maximal liquid torqueTmﬂyuq; Tmq > 0.9*Tmﬂ;uq; 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 enginetorque Tnﬂ is in an interval between 80% and 90% of themaximal liquid torque Tmaxgiq; 0.8*Tmax_liq < Treq < 0.9*Tmax_liq;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 enginetorque Tug is lower than or equal to 80% of the maximal liquidtorque Tmﬂyuq; Tmq S 0.8*Tmﬂyuq; then 100% fuel in liquid state 126 may be provided to the engine 101.

As mentioned above, the first pressure threshold PL¿h may,according to some embodiments, indicate a pressure below whichonly fuel in liquid state 126 is to be provided to the engine101. The second pressure threshold P¿¿h may, according to someembodiments, 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, apressure Pgæ of the fuel in the gaseous state 125 isdetermined. The gas pressure Pqß may e.g. be determined byusage of one or more sensors. The one or more sensors may bearranged within the tank 121 and/or with the at least one gaseous state fuel output conduit 122.

The determined pressure Pgæ of the fuel in the gaseous state125 may then be compared with the first pressure thresholdPiih. Then, if the determined pressure Pgæ is lower than thefirst pressure threshold Prih; Pgæ < PL¿h; the fuel flows arecontrolled through one or more of the at least one gaseousfuel output conduit 122 and the at least one liquid fueloutput conduit 123 such that only fuel in liquid state 125 isprovided to the engine 101.

The determined pressure Pgæ of the gaseous state fuel 125 withmay also be compared with the second pressure threshold P¿;h.Tf the determined gas pressure Pgæ is higher than the pressurethreshold Pginí Pﬁß > P¿¿h; fuel flows through one or more ofthe at least one gaseous fuel output conduit 122 and the atleast 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 ormore of the at least one gaseous fuel output conduit 122 andthe 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 ormore of the first pressure threshold Prﬂh and the secondpressure threshold P¿;h are adjusted such that an amount of the fuel in the gaseous state 125 needed for the engine 101 to lO 26 reach the at least one upcoming operating point is available in the tank l2l before the operating point occurs.

By adjusting the pressure interval PL;h - P¿;h between thefirst pressure threshold Prﬂh and the second pressure thresholdPgih, the amount of gaseous state fuel l25 being available forcombustion in the engine may be adapted for the upcoming usageof the vehicle lOO. Hereby, fuel having a higher octanenumber/rate, i.e. gaseous state fuel, will to a much largerextent be available for the combustion when it is needed, e.g.when the vehicle reaches a long uphill stretch and/or shouldperform an acceleration. Thus, a flexible control of the stateof fuel being provided to the engine is achieved, which isoptimized for the actual usage of the vehicle. This is a greatimprovement over the conventional mechanical economizer, whichperformed switching only based on the gas pressure Pgæ, oftenresulting in a shortage of gaseous state fuel when higher torques are requested.

The pressure interval PL;h - Pgﬂh created by the embodiments ofthe present invention may, as is mentioned above, be utilizedfor an accurate control of the state of fuel being provided tothe engine. Hereby, a more efficient usage of the gaseousstate fuel, and thereby also a more powerful engine, may beachieved within the interval. Also, the more exact andreliable control of the state of fuel being provided to theengine reduces the need for opening the safety valve 124,which lowers the fuel consumption over time. By adjusting therange of the pressure interval PL;h - Pgih, the pressureinterval within which such an efficient and accurate usage ofthe gaseous state fuel is usable may be adjusted to precisely match the future/upcoming usage of the vehicle. lO 27 In other words, the choice of the state of fuel to be providedto the engine may, by usage of the present invention, becoupled/matched to an upcoming usage of the vehicle, e.g. toan upcoming operational point of the vehicle and/or to anupcoming driving situation, which makes it possible tooptimize the state of fuel and/or the ratio between gaseousand liquid states of the fuel being provided to the engine.The present invention facilitates a reliable and accuratecontrol of the controllable electronic economizer such thatfuture vehicle usage is taken into consideration. Hereby, theprobability for the engine to be able to provide a futureupcoming requested torque is greatly increased, since theamount 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 describedadjustment, for the first pressure threshold PL¿h may bedetermined in a number of ways. According to an embodiment,the first pressure threshold Pyﬂh is determined based on atleast one feature of the fuel tank l2l, such as for example asize, a geometrical design and/or an output conduit design forthe fuel tank l2l. According to an embodiment, the firstpressure threshold Prih is determined based on at least onefeature of a fuel providing system 120 arranged for providingthe fuel from the tank l2l to the engine lOl, wherein suchsystem features may include geometrical forms and/ordimensions for piping between the tank l2l and the engine lOland/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 describedadjustment, for the second pressure threshold P2¿m may bedetermined in a number of ways. According to an embodiment, the second pressure threshold P¿¿h may be determined based on a 28 required volume of the gaseous state fuel 125 in the tank 121and/or on the type and/or usage of the vehicle 100. Forexample, a bus or a garbage truck, i.e. vehicles oftenmoving/driving short distances between its stops, may have alower/smaller value for the second pressure threshold P2¿m,whereas e.g. long haulage trucks, i.e. vehicles driving/movinglonger distances between its stops, may have a higher/greatervalue for the second pressure threshold P2¿m. Further,according to an embodiment, the second pressure threshold P¿¿hmay be determined based on at least one feature of the fueltank 121, a level of fuel in the fuel tank 121, a relationbetween amounts of the gaseous state 125 and liquid state 126fuel 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 pressurethreshold Prﬂh and the second pressure threshold Pgih areadjusted 420 based on the determined at least one upcomingoperation point, where the at least one upcoming operatingpoint is determined based on one or more of informationrelated 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 vehiclemay, according to various embodiments, include externalinformation, internal information, driver inputtedinformation, information provided by at least one othervehicle, information provided by at least one externaldatabase, information provided by a tachograph, informationrelated to a driving schedule, information related to aservice schedule, and/or information related to a weight of the vehicle 100. The information may be provided by a driver lO 29 of the vehicle, for example by a driver inputting a drivingschedule, 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, forexample a system estimating the vehicle weight. In thisdocument, 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 vehiclescommunicating with the vehicle lOO, via so called vehicle-to-vehicle (V2V) communication, where the vehicles shareinformation with other vehicles. The information may also beprovided by one or more infrastructure devices l7O (in figurel), e.g. including one or more servers, databases and/orregisters, via so called vehicle-to-infrastructure (V2I)communication, where the information may first have beencollected by other vehicles, and may have been provided to theone or more infrastructure devices l70. The vehicle may thusinclude at least one communication device l6O (in figure l),arranged for V2V communication, for V2I communication and/or for vehicle-to-everything (V2X) communication.

The upcoming usage of the vehicle may, according to anembodiment, include a break and/or stop time period TSUW longerthan a stop time threshold Taßpih, e.g. a service or permanentbreak and/or stop. As mentioned above, there are in someregions rules stipulating how long a vehicle with anessentially full tank should be able to be parked. Tf a breakand/or stop time period TSUW longer than a stop time thresholdTﬁßpih will come, the first pressure threshold PL¿h may bereduced, such that the risk for having to open he safety valvel24 is reduced, since more gaseous state fuel l25 is then consumed. However, the first pressure threshold PL¿h has to be lO high enough, i.e. equal to or above a minimum gas pressurethreshold Pgægmn, in order for the system to be able to push the fuel out from tank l2l.

The upcoming usage of the vehicle may, according to anembodiment, include a number of breaks and/or stops Nmßpgreater than a number threshold Ngumgm; Ngum > Numpmh. Forexample, for busses and/or garbage trucks having many stops,multiple stops and accelerations, and possibly also activationof garbage compression devices or the like at the stops, arecommon in the normal operation of some vehicles. Therefore, ifa number of breaks and/or stops Nyxm greater than a numberthreshold will come; Nuxm > Numgmh; then the first and/or second pressure threshold PL¿h / P¿mh may be reduced/increased.

The upcoming usage of the vehicle may, according to anembodiment, also include a number of breaks and/or stops Nmßpsmaller than a number threshold Ngumgm; Ngum < Numpmh. Forexample, for long haulage vehicles, long stretches/distancesare often travelled between the stops. Therefore, if a numberof breaks and/or stops Ngum smaller than a number thresholdwill come; Nuxm < Numgmh; then the first and/or second pressure threshold PL¿h / P¿mh may be reduced/increased.

The upcoming usage of the vehicle may, according to anembodiment, also include a usage resulting in an engine loadLulgreater than a load threshold Luuw; Lu1> Luuuﬁ e.g. for avehicle reaching an uphill road section and/or for a vehicleabout to be accelerated. Therefore, if an engine load Lugreater than a load threshold Luuw; Lu1> Luuw; will come,then the first and/or second pressure threshold PL¿h / P¿mh may be reduced/increased.

The upcoming usage of the vehicle may, according to an embodiment, also include a usage resulting in an engine load lO Bl Lﬁlsmaller than a load threshold Lamm; LH1< Lahuﬁ e.g. for avehicle reaching a downhill road section and/or for a vehicleabout to decelerate. Therefore, if an engine load Lﬂlsmallerthan a load threshold Laem; LH1< Lamm; will come, then thefirst and/or second pressure threshold PL¿h / P¿¿h may be reduced/increased.

The upcoming usage of the vehicle may, according to anembodiment, also result in a vehicle weight W greater than aweight threshold Ww; W > WÜÜ e.g. when transporting heavygoods and/or material. Therefore, if a vehicle weight Wgreater than a weight threshold Ww; W > Waﬁ will come, thenthe first and/or second pressure threshold PL¿h / P¿¿h may be reduced/increased.

The upcoming usage of the vehicle may, according to anembodiment, also result in a vehicle weight W smaller than aweight threshold Ww; W < WÜU Therefore, if a vehicle weight Wsmaller than a weight threshold Ww; W < WÜÜ will come, thenthe first and/or second pressure threshold PL¿h / P¿¿h may be reduced/increased.

As mentioned above, the at least one upcoming operating pointfor the engine lOl may be determined 410 at least partly basedon information related to a road section ahead of the vehicle,and the adjustment of one or more of the first and secondpressure thresholds PL¿h, P¿¿h is then based on this determined operating point.

According to an embodiment, the information related to theroad section ahead of the vehicle lOO may include informationrelated to a speed limit for the road section, a topology ofthe road section, a curvature of the road section and/or a traffic situation within the road section. lO 32 The first pressure threshold PL¿h may for example be reduced ifthe upcoming road section includes a lower speed limit, adownhill stretch, one or more curves and/or slow moving traffic.

Correspondingly, the first pressure threshold PL¿h may forexample be increased if the upcoming road section includes ahigher speed limit, an uphill stretch, one or more straight sections curves and/or fast moving, or no, traffic.

The second pressure threshold P¿¿h may be reduced and/or increased based on if the upcoming road section includes oneor 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 thevehicle lOO may e.g. be based on positioning information, mapinformation, topology information, information provided by atleast one other vehicle or at least one infrastructure device(V2V, V2I, V2X) 170, and/or information gathered by the vehicle lOO itself at an earlier point in time.

Thus, the determination of the operating point may, accordingto various embodiments of the present invention, be performedbased also on information related to essentially any parameterbeing 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 positioninginformation, digital map information, topographicalinformation, curvature information, speed limit information,traffic information, radar-based information, camera-basedinformation, requested vehicle speed information, other vehicle distance information, other vehicle speed information, 33 vehicle weight information, information obtained from othervehicles than the vehicle 100, road information and/orpositioning information stored previously on board the vehicle100, and/or information obtained from traffic systems related to that road section.

The information related to the upcoming road section may beobtained in various ways. It may be determined on the basis ofmap data, e.g. from digital maps including e.g. topographicalinformation, in combination with positioning information, e.g.GPS (global positioning system) information. The positioninginformation may be used to determine the location of thevehicle relative to the map data so that the road sectioninformation may be extracted from the map data. Variouspresent-day cruise control systems use map data andpositioning information. Such systems may then provide thesystem for the present invention with map data and positioninginformation, thereby minimizing the additional complexity involved in determining the road gradient.

The road section information may thus e.g. be obtained on thebasis of a map in conjunction with GPS information. Theinformation may also be obtained by usage of radar equipment,one or more cameras, one or more other vehicles providinginformation, information storing systems on board, and/or traffic systems related to the section of road.

The information may be used for performing simulations relatedto the vehicle 100 for the upcoming road section, such as e.g.on or more future speed profiles for the actual vehicle speedfor 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 lO 34 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 onboard the vehicle at a predetermined rate, e.g. at a rate of lHz, which means that a new simulation result is provided everysecond. The section of road for which the simulation isconducted represents a predetermined distance ahead of thevehicle, e.g. it might be l km long. The section of road mayalso 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 Tmﬂyuq is usedin various embodiments of the present invention. The maximalliquid torque Tmﬂ_nq may, according to an embodiment, bedetermined adaptively during normal operation of the vehicle,i.e. when the engine lOl runs. The determination of themaximal liquid torque Tmﬂyuq is then based on a performance ofthe engine lOl. For example, information related to thecontrol of the fluid flows, i.e. control of the electricallycontrolled economizer l27, is stored and is utilized, togetherwith the performance of the engine lOl resulting from thecontrolled flows, i.e. resulting from the control of theeconomizer, for the adaptive determination of the maximalliquid torque Tmﬂyuq. A value of the maximal liquid torqueTmﬂ_hq may here for example be actively adjusted, andthereafter the maximal liquid torque Tmﬂyuq is adaptivelydetermined based on that executed/performed active adjustmentand on a performance of the engine lOl resulting from theactive adjustment of the maximal liquid torque Tmﬂyuq. In otherwords, a change/adjustment of the maximal liquid torque Tmﬂyuqis here first actively effected, and thereafter the effect of this change/adjustment is analyzed. The analysis is then l0 possibly followed by another adjustment/change of the maximal liquid torque Tmﬂruq, and so on.

According to an embodiment of the present invention, themaximal liquid torque Tmﬂyuq is determined by running a testengine corresponding to the engine lOl used in the vehicle lOOon the liquid state fuel l26 in a test cell/laboratoryenvironment, and by measuring a resulting test torque Tnqieﬁ.The maximal liquid torque Tmﬂyuq is then determined based on the test torque Tnqieï.

According to an embodiment, the maximal liquid torque Tmﬂyuq isdetermined 410 by first determining a tendency for engineknocking when the fuel in the liquid state is provided to theengine, e.g. based on information provided by one or moreknocking sensors, which may be acoustic sensors, arranged atthe engine lOl and/or based on a knowledge of the octanenumber of the fuel provided to the engine. When the tendencyfor engine knocking has been determined, the maximal liquidtorque Tmﬂ_nq may be determined based on the determinedtendency, e.g. by, if knocking is detected, adjusting theignition, and thereby also adjusting the providable torque,until the knocking stops. The maximal liquid torque Tmﬂyuq isthen determined as the torque providable without engine knocking occurring.

Correspondingly, the maximal gaseous torque Tmﬂgws is,according to an embodiment, determined 410 by firstdetermining a tendency for engine knocking when the fuel inthe gaseous state is provided to the engine, e.g. by usage ofthe above mentioned one or more knocking sensors and/or basedon the octane number of the fuel provided to the engine. Whenthe tendency for engine knocking has been determined, the gaseous liquid torque Tmﬂgws may be determined based on the lO 36 determined tendency, by adjusting the ignition until theknocking stops, as mentioned above. The gaseous liquid torqueTmﬂgws is then determined as the torque providable without engine knocking occurring.

The determination of the maximal gaseous torque Tmﬂgwsprovidable by the engine lOl may be performed by running atest engine corresponding to the engine lOl in the vehicle lOOe.g. in a test cell/laboratory environment, and measuring a resulting maximal gaseous torque Tmﬂgws.

A person skilled in the art will appreciate that theembodiments of the method for controlling a state of fuelprovided from a fuel tank l2l to an engine lOl, according tothe present invention, may also be implemented in a computerprogram, which, when it is executed in a computer, instructsthe computer to execute the method. The computer may beincluded in the herein described system and/or may becoupled/connected to the herein described system. The computerprogram is usually constituted by a computer program product603 stored on a non-transitory/non-volatile digital storagemedium, in which the computer program is incorporated in thecomputer-readable medium of the computer program product. Thecomputer-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 controlunit/system/means 600/l40. The control unit/system/means600/l4O comprises a computing unit 60l, which may beconstituted by essentially any suitable type of processor ormicrocomputer, for example a circuit for digital signal processing (Digital Signal Processor, DSP), or a circuit 37 having a predetermined specific function (Application SpecificIntegrated Circuit, ASIC). The computing unit 601 is connectedto a memory unit 602 arranged in the control unit/system/means600/140, which memory unit provides the computing unit 601with, for example, the stored program code and/or the storeddata which the computing unit 601 requires to be able toperform computations. The computing unit 601 is also arrangedto store partial or final results of computations in the memory unit 602.

In addition, the control unit/system/means 600/140 is providedwith devices 611, 612, 613, 614 for receiving and transmittinginput and output signals. These input and output signals maycomprise waveforms, impulses, or other attributes which, bythe devices 611, 613 for the reception of input signals, canbe detected as information and can be converted into signalswhich can be processed by the computing unit 601. Thesesignals are then made available to the computing unit 601. Thedevices 612, 614 for the transmission of output signals arearranged to convert signals received from the computing unit601 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 andtransmitting input and output signals can be comprise one ormore of a cable; a data bus, such as a CAN bus (Controller Area Network bus), a MOST bus (Media OrientatedSystems Transport bus), or some other bus configuration; or bya wireless connection. A person skilled in the art willappreciate that the above-stated computer can be constitutedby the computing unit 601 and that the above-stated memory may be constituted by the memory unit 602. 38 Control systems in modern vehicles commonly comprisecommunication bus systems including one or more communication buses for linking a number of electronic controlunits (ECU's), or controllers, and various components locatedon the vehicle. Such a control system may comprise a largenumber of control units/means and the responsibility for aspecific function can be divided amongst more than one controlunit/means. Vehicles of the shown type thus often comprisesignificantly more control units/means than are shown infigures 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 implementedin the control unit/system/means 600/140. The invention canalso, however, be implemented wholly or partially in one ormore other control units/systems/means already present in thevehicle, or in some control unit/system/means dedicated to the present invention.

According to an aspect of the invention, a control unit 140arranged for controlling a state of fuel provided from a fueltank 121 to an engine 101 of a vehicle 100 is presented. Asmentioned above, the fuel tank 121 stores fuel in gaseous 125and liquid 126 state, and includes at least one gaseous fueloutput 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 operatingpoint for the engine 101 based on one or more of informationrelated to an upcoming usage of a vehicle 100 including theengine 101 and the fuel tank 121, and information related to a road section ahead of the vehicle 100. 39 The control unit 140 further includes adjustment unit/means142, arranged for adjusting 420, based on the determined atleast one upcoming operation point, one or more of a firstpressure threshold Prﬂh and a second pressure threshold Piih.As mentioned above, the first pressure threshold Pyih indicatesa pressure below which only the fuel in liquid state 126 isprovided to the engine 101, and the second pressure thresholdP¿;h 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 ofthe at least one gaseous fuel output conduit 122 and the atleast one liquid fuel output conduit 123 based on at least oneor more of the first pressure threshold Prih and the second pressure threshold Pglh.

By activation of the above described determination unit/means141, the adjustment unit/means 142, and the controllingunit/means 143, the above described method is performed, which has the above mentioned advantages.

Here and in this document, units/means are often described asbeing arranged for performing steps of the method according tothe 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 2illustrated as including separately illustrated units/means141, 142, 143. Also, the control system/means 140 may includeor be coupled to other control means/units, such as e.g. anengine control device/means, a clutch control unit, an exhausttreatment 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 isimplemented in at least two different physical units/devices.These means/units/devices 141, 142, 143, 140 may also be atleast to some extent logically separated and implemented in atleast two different physical means/units/devices. Further,these means/units/devices 141, 142, 143, 140 may be bothlogically and physically arranged together, i.e. be part of asingle logic unit which is implemented in a single physicalmeans/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 inputinto, and are utilized by at least one processor when theunits/means are active and/or are utilized for performing itsmethod step, respectively. It should be noted that the controlunit/means 140 may be implemented at least partly within thevehicle 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 abovecorrespond to the claimed means 141, 142, 143 arranged forperforming the embodiments of the present invention, and the present invention as such.

The control unit according to the present invention can bearranged for performing all of the above, in the claims, andin the herein described embodiments method steps. The controlunit is hereby provided with the above described advantages for each respective embodiment.

A skilled person also realizes that the above describedcontrol unit may be modified according to the different embodiments of the method of the present invention. The 41 present invention is also related to a vehicle 100, such as atruck, a bus or a car, including the herein described control unit 140.

The inventive method, and embodiments thereof, as describedabove, may at least in part be performed with/using/by atleast one device. The inventive method, and embodimentsthereof, as described above, may be performed at least in partwith/using/by at least one device that is suitable and/oradapted for performing at least parts of the inventive methodand/or embodiments thereof. A device that is suitable and/oradapted for performing at least parts of the inventive methodand/or embodiments thereof may be one, or several, of acontrol unit, an electronic control unit (ECU), an electroniccircuit, a computer, a computing unit and/or a processing unit.

With reference to the above, the inventive method, andembodiments thereof, as described above, may be referred to asan, at least in part, computerized method. The method being,at least in part, computerized meaning that it is performed atleast in part with/using/by the at least one device that issuitable and/or adapted for performing at least parts of the inventive method and/or embodiments thereof.

With reference to the above, the inventive method, andembodiments thereof, as described above, may be referred to asan, at least in part, automated method. The method being, atleast in part, automated meaning that it is performedwith/using/by the at least one device that is suitable and/oradapted 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 42 encompasses all different embodiments being included within the scope of the independent claims.

Claims

43 Claims

1. A method (400) for controlling a state of fuelprovided from a fuel tank (121) to an engine (101), said fueltank (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 forsaid engine (101) based on one or more of information relatedto an upcoming usage of a vehicle (100) including said engine(101) and said fuel tank (121), and information related to aroad section ahead of said vehicle (100); - adjusting (420), based on the determined at least oneupcoming operation point, one or more of a first pressurethreshold Pyih and a second pressure threshold P¿¿h, whereinsaid first pressure threshold Pyﬂh indicates a pressure belowwhich only said fuel in liquid state (126) is provided to saidengine (101), and said second pressure threshold P¿¿h indicatesa 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 atleast one gaseous fuel output conduit (122) and said at leastone liquid fuel output conduit (123) based on at least one ormore of said first pressure threshold Prﬂh and said second pressure threshold Pgih.

2. The method (400) as claimed in claim 1, wherein saidadjusting (420) of one or more of said first pressurethreshold Prﬂh and said second pressure threshold P¿¿h isperformed such that an amount of said fuel in said gaseousstate (125) needed for said engine (101) to reach said atleast one upcoming operating point is available in said tank (121). l0

3. The method (400) 44 as claimed in any one of claims l-2, wherein said information related to said upcoming usage includes one or more of: - external information; - internal information; - driver inputted information; - information- information- information- information- information- information - information

4. The method (400) provided by at least one other vehicle; provided by at least one external database; provided by a tachograph; related torelated torelated torelated to ö. ö. driving schedule;loading schedule;service schedule; and weight of said vehicle (lOO). as claimed in any one of claims l-3, wherein said upcoming usage includes one or more of: - a permanent break and/or stop; - a break and/or stop time period Taßp Tstopith; - a numberthreshold;- a number threshold; Nstop > Nstop_th/° Nstop < Nstop_th/° of breaks and/or stops Naßp of breaks and/or stops Naßp longer than a stop time greater than a number smaller than a number - a usage resulting in an engine load Lﬁlgreater than a load threshold- a usagethreshold - a usage weight threshold Wüﬁ Len_th/° Len_th/° W > Wtní Len > Len_th/°resulting in an engine load Lﬂlsmaller than a loadLen < Len_th/° resulting in a vehicle weight W greater than a and - a usage resulting in a vehicle weight W smaller than a weight threshold Wüﬁ W < Wth.

5. The method (400) as claimed in any one of claims 1-4,wherein said information related to said road section ahead ofsaid 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 ofsaid 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 oneor 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 Pgæ ofsaid gaseous state fuel (125) is greater than said second pressure threshold Pginí Fﬁß > P¿;h.

8. The method (400) as claimed in any one of claims 1-7,wherein said controlling (430) of said fuel flows through oneor 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) 46 is provided to said engine (101) if a gaseous pressure Pgæ ofsaid gaseous state fuel (125) is smaller than said first pressure threshold PL;h; Fgﬂ < Pyih.

9. The method (400) as claimed in any one of claims 1-8,wherein said controlling (430) of said fuel flows through oneor more of said at least one gaseous fuel output conduit (122)and said at least one liquid fuel output conduit (123) isbased on a requested engine torque Tug if a gaseous pressurePgæ of said gaseous state fuel (125) is greater than saidfirst pressure threshold Prﬂh and smaller than said second pressure threshold Pglh; Prih < Pqß < P¿¿h.

10. The method (400) as claimed in any one of claims 1-9,wherein said adjusting (420) of said first pressure thresholdPL¿h results in a value of said first pressure threshold Pyihbeing greater than a minimum first pressure threshold valuePriwmnu said minimum first pressure threshold value Pyiwmﬂbeing related to a capability of said fuel tank (121) toprovide said fuel flows through one or more of said at leastone 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 pressurethreshold P¿¿h results in a value of said second pressurethreshold P¿;h being smaller than a maximum second pressurethreshold value P¿;@mﬂ, said maximum second pressure thresholdvalue P¿;@mﬂ being related to a maximally allowed pressure Pgægmx 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). 47

13. A computer program comprising instructions which, whenthe 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 stateof 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 outputconduit (122) and at least one liquid fuel output conduit(l23); characterized by - means (141) arranged for determining (410) at least oneupcoming operating point for said engine (101) based on one ormore 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 saidvehicle (100); - means (142) arranged for adjusting (420), based on thedetermined at least one upcoming operation point, one or moreof a first pressure threshold Pyih and a second pressurethreshold P¿¿h, wherein said first pressure threshold Pyihindicates a pressure below which only said fuel in liquidstate (126) is provided to said engine (101), and said secondpressure threshold P¿;h indicates a pressure above which onlysaid fuel in said gaseous state (125) is provided to saidengine (101); and - means (143) arranged for controlling (430) fuel flowsthrough one or more of said at least one gaseous fuel outputconduit (122) and said at least one liquid fuel output conduit(123) based on at least one or more of said first pressure threshold Prﬂh and said second pressure threshold Piih.