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    • 专利摘要:
    The present invention relates to a method for stopping an internal combustion engine (101), said internal combustion engine (101) having at least one combustion chamber (209) and a crankshaft (112) being arranged to be propelled by said at least one combustion chamber (209), wherein intake of gas to said at least one combustion chamber (209) is controlled by at least one intake valve (211), and wherein evacuation of said at least one combustion chamber (209) is controlled by at least one exhaust valve (213). The method includes, when said internal combustion engine (101) is to be stopped:- turning off fuel injection,- with fuel injection turned off, controlling an intake valve (211) and/or an exhaust valve (213) of said at least one combustion chamber (209) such that, following compression in said at least one combustion chamber (209), pressure in said combustion chamber (209) is reduced to reduce a crankshaft (112) propelling power caused by gas expansion following said compression.Fig. 5B
    公开号:SE1651045A1
    申请号:SE1651045
    申请日:2016-07-12
    公开日:2018-01-13
    发明作者:Hoeckerdal Erik；Stenlåås Ola
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    lOMETHOD AND SYSTEM FOR STOPPING AN INTERNAL COMBUSTION ENGINEField of the inventionThe present invention relates to combustion processes, and inparticular to a method and system for stopping an internalcombustion engine. The present invention also relates to avehicle, as well as a computer program and a computer programproduct that implement the method according to the invention.Background of the inventionWith regard to vehicles in general, and at least to someextent heavy/commercial vehicles such as trucks, buses and thelike, there is constantly ongoing research and developmentwith regard to increasing fuel efficiency and reducing exhaustemissions.
    This is often at least partly due to growing governmentalconcern in pollution and air quality, e.g. in urban areas,which has also led to the adoption of various emissionstandards and rules in many jurisdictions.
    Undesired emission of substances can be reduced by reducingfuel consumption and/or through the use of aftertreatment(purifying) of exhaust gases emanating from combustion.
    With regard to fuel consumption there are various ways ofreducing such consumption, e.g. by controlling the combustionprocess. Furthermore, brake energy can be regenerated toelectrical energy in electric hybrid vehicles. Other methodsinclude improving use of energy, e.g. by reducing unnecessarybraking. Fuel consumption may also be reduced using enginestart/stop (a.k.a. stop/start) functionality, where theinternal combustion engine is stopped when the vehicle isstanding still, e.g. due to traffic lights, to be startedlOagain when the vehicle is to be set in motion to avoid fuelconsumption when the vehicle is standing still.
    Apart from fuel consumption and emissions, there may also berestrictions regarding the sound being produced by a vehiclein motion or when standing still, e.g. in city centres.Summary of the inventionIt is an object of the present invention to provide a methodand system for stopping an internal combustion engine thatstops the internal combustion engine in a short period of timethereby reducing noise produced by the engine. This isachieved by a method according to claim l.
    According to the present invention, it is provided a methodfor stopping an internal combustion engine, said internalcombustion engine having at least one combustion chamber and acrankshaft being arranged to be propelled by said at least onecombustion chamber, wherein intake of air to said combustionchamber is controlled by at least one intake valve, andwherein evacuation of said combustion chamber is controlled byat least one exhaust valve. The method includes, when saidinternal combustion engine is to be stopped:- turning off fuel injection,- with fuel injection turned off, controlling an intake valveand/or an exhaust valve of said combustion chamber such that,following compression in said combustion chamber, pressure insaid combustion chamber is reduced to reduce a crankshaftpropelling power caused by gas expansion following saidcompression.
    Start-stop systems, also known as stop-start systems,controlling internal combustion engines are becomingincreasingly frequent as regulations regarding fuel economylOand emissions are becoming stricter. Start-stop systemsautomatically, e.g. through the use of a vehicle controlsystem, stops, i.e. turns off, and restarts the internalcombustion engine in situations where the internal combustionengine is idling to reduce the amount of time spent idling tothereby reduce fuel consumption and emissions. In addition tofuel savings, start-stop functionality may also be beneficialfrom a noise restriction point of view, since noise producedby the internal combustion engine when running is essentiallyeliminated when the engine is stopped.
    In fact, there may restrictions regarding noise levels thatrequire the internal combustion engine to be turned off whenthe vehicle is standing still, e.g. in city centres, to fulfilnoise restrictions. Also, in some instances it may be requiredto turn off the internal combustion engine when the vehicle isin motion and switch to electrical propulsion e.g. in citycentres to fulfil noise regulations. According to theinvention, it is provided a method for stopping the internalcombustion engine in a short period of time so that the noiseproduced by the internal combustion engine is reduced by thereducing the time the internal combustion engine is running.
    This is accomplished by turning off fuel injection, and, withfuel injection turned off, controlling an intake valve and/oran exhaust valve of a combustion chamber such that, followingcompression in said combustion chamber, pressure in thecombustion chamber is reduced to reduce crankshaft propellingpower caused by gas expansion following said compression.
    In general, when stopping an internal combustion engine,valves are controlled in the same manner as when the internalcombustion engine is running, where the engine is stopped byturning off fuel injection. According to the invention, valvesare controlled differently when stopping the engine. InlOgeneral, crankshaft rotation is subjected to a brake forcewhen e.g. a piston reciprocating in the combustion chamber, orother means such as a rotor of a Wankel engine, acting in thecombustion chamber compresses air provided during an intakephase. Following compression, however, a large part of thework produced during compression is returned as crankshaftmotive force from the following gas expansion, e.g. byproviding a crankshaft propelling force on a piston or othermeans in the combustion chamber, which occurs also when thereis no combustion in the combustion chamber.
    According to the invention, the compression still takes place,at least to a large extent, while the propelling force fromgas expansion is reduced by reducing the pressure in thecombustion chamber prior to or at the beginning of thefollowing expansion stage. This is accomplished by opening anintake valve and/or exhaust valve at the end of compressionstage and/or at the beginning of the following expansionstage. In this way, the stopping of the engine benefits fromthe crankshaft retarding force generated through compression,while the following crankshaft accelerating force from gasexpansion is reduced or eliminated by allowing gas expansionthrough one or more valves instead of acting against e.g. apiston or other means in the combustion chamber. That is,pressure, and hence the crankshaft propelling power, isreduced in relation to the pressure, and crankshaft propellingpower, obtained when valves are not opened at the end ofcompression stage or beginning of expansion stage.
    Pressure may be reduced e.g. to atmospheric pressure, or someother suitable pressure being lower than the pressure beingthe result of the compression.
    This substantially reduces the time it takes to stop theinternal combustion engine, and thereby the noise producedlOwhen stopping the engine is also reduced since the time noiseis produced is reduced. The invention is applicable to anyinternal combustion process involving a compression stage andfollowing expansion stage.
    The compression can be arranged to be reduced by changing anopening time of one or more intake valves and/or one or moreexhaust valves of the combustion chamber. For example, anintake valve and/or an exhaust valve can be arranged to beopened during the last part of, or at the end of, thecompression stage to thereby allow expansion by evacuationthrough the valve. Alternatively, an intake valve and/or anexhaust valve can be arranged to be opened at the beginning ofthe expansion stage that follows the compression stage. Inthis way, although the expansion may occur to some extent, amajor portion of the expansion will still take place throughthe open valve. In this way, the force exerted on the means inthe combustion chamber interacting with the crankshaft, suchas e.g. a reciprocating piston, will be reduced and hence thepropelling force provided to the crankshaft is also reduced.
    According to embodiments of the invention, the intake valveand/or exhaust valve is maintained open from the end of thecompression stage to the beginning of the exhaust stage.According to embodiments of the invention, a valve may openfirst at the end of the compression stage, where a valve (thesame or a different) is opened at the beginning of thefollowing expansion stage, e.g. taking into considerationlimitations regarding valve clearance when opening valvesat/near top dead centre TDC of a piston.
    The intake valve and/or exhaust valve may be controlled toreduce crankshaft propelling power caused by expansionfollowing compression at least substantially until the speedof rotation of said crankshaft is reduced to zero, or at leastlOuntil the speed of rotation of the crankshaft has been reducedto some suitable speed.
    Furthermore, valves may be controlled in a conventional mannerduring the combustion cycle apart from the particular controlto reduce the propelling effect from expansion. Hence, priorto said compression, the intake valve and/or exhaust valve ofsaid combustion chamber may be opened for intake of gas (air),e.g. according to normal operation, to provide gas forcompression to obtain the retarding force acting on thecrankshaft where the propelling force is then reducedaccording to the above.
    According to embodiments of the invention, pressurized air isprovided to the combustion chamber to thereby increasecompression and the retarding force.
    According to embodiments of the invention, an intake valve ofsaid combustion chamber is opened for intake of air forcompression, and following compression of said intake of air,an exhaust valve of said combustion chamber is opened toreduce pressure in said combustion chamber to thereby reducecrankshaft propulsion by gas expansion.
    In case the internal combustion engine operates according to acombustion cycle including a compression stroke followed by anexpansion stroke, pressure may be reduced in said combustionchamber by opening an intake valve and/or an exhaust valve atthe end of the compression stroke and/or at the beginning ofthe following expansion stroke. Hence the present inventionmay be used e.g. in two stroke or four stroke internalcombustion engines. The invention is, however applicable alsofor internal combustion engines operating according to otherprinciples such as Wankel engines.lOWith regard to the control of intake valve and/or exhaustvalve to reduce compression this may be accomplished byphasing of at least one camshaft, or part thereof, to therebycontrol opening and/or closing of an intake valve and/orexhaust valve according to the above. The camshaft can bearranged to be phase shifted (phased), e.g. using phasers, toaccomplish control of the valves according to the above. Thatis, a camshaft can be arranged to comprise a degree of freedomof rotation independent from the rotation of the crankshaft.For example, a camshaft may be designed to allow a phasingcorresponding e.g. to any suitable number of crankshaftdegrees in the interval lO-lOO degrees, where the phasing canbe arranged to be both retarding and advancing in relation tocrankshaft rotation.
    Other means may also be used, in the alternative, or inaddition, to control the valves. For example, additionalcamshaft tappets may be utilised, where such tappets may bearranged to be selectively engageable. In this way additionalvalve openings may be achieved, and used to increase theretarding force in order to stop the engine in a shorterperiod of time.
    Such additional valve openings may be arranged to be used e.g.only when stopping the internal combustion engine, and notduring normal operation when the internal combustion engine isrunning. It is also contemplated that the valves may becontrolled independently from the rotations of the crankshaft,e.g. through the use of suitable electrical / mechanical /pneumatical means or combinations thereof.
    When the internal combustion engine is of a kind where areciprocating member reciprocates in the combustion chamberthe intake valve and/or exhaust may be arranged to becontrolled in a variable dependence of the position of thelOreciprocating member in said combustion chamber, e.g. inrelation to the position of the reciprocating member inrelation to top dead centre TDC so that valves open and closein a desired manner to obtain benefits of the invention.
    The internal combustion engine may be of a designed such thata single intake valve and a single exhaust valve,respectively, acts against the combustion chamber, and one orboth these valves may be arranged to open according to theabove. According to embodiments of the invention there may betwo or more intake valves and/or exhaust valves, and accordingto such designs one or more of each kind of valve may beopened.
    Furthermore, although the above describes operation for asingle combustion chamber internal combustion engines ingeneral comprises a plurality of combustion chambers, andvalves of all or at least a plurality of the combustionchambers of the internal combustion engine may be arranged tobe controlled according to the above. For example, whencontrolling valves using phasing, a camshaft may be used tocontrol valves of a plurality of, or all of, the combustionchambers of the internal combustion engine.
    Furthermore, opening and closing of intake valves may becontrolled by a first camshaft, and opening and closing ofexhaust valves may be controlled by a second camshaft. Atleast one of said first and second camshafts may be controlledto open/close valves according to the above.
    The intake valves and/or exhaust valves may also be controlledin any other suitable manner, such as by electrical, pneumaticor mechanical means, and may be arranged to be individuallycontrollable when reducing the crankshaft propelling force bylOcontrolling expansion following compression in the combustionchambers of the vehicle.
    Furthermore, in dependence of available clearance, the pistonmay be provided with recesses or cut-outs on the piston headin order to allow valves to be open while the piston reachesTDC in order to avoid conflict with the valves. Such designissues, however, are known to the person skilled in the art.
    Further characteristics of the present invention andadvantages thereof are indicated in the detailed descriptionof exemplary embodiments set out below and the attacheddrawings.Brief description of the drawingsFig. lA illustrates a powertrain of an exemplary vehicle inwhich the present invention advantageously can be utilised;Fig. lB illustrates an example of a control unit in a vehiclecontrol system;Fig. 2 illustrates an example of a combustion chamber suitablefor being controlled according to embodiments of theinvention.
    Fig. 3 illustrates an exemplary method according to oneembodiment of the present invention.
    Fig. 4 illustrates an exemplary system involving an in-linesix-cylinder internal combustion engine being controlledaccording to embodiments of the present invention.
    Figs. 5A-B shows control exemplary control strategiesaccording to embodiments of the invention.Detailed description of exemplary embodimentsIn the following detailed description the present inventionwill be exemplified for a vehicle. The invention is, however,applicable also in other kinds of transportation means, suchas air and water crafts. The invention is also applicable infixed installations. Further the terms ”intake valve” and”exhaust valve” in the description and the claims are used todenote any means that open and close a passage to a combustionchamber for inlet of air and evacuation of combustionresiduals, respectively.
    Furthermore, the invention is described in relation to aninternal combustion engine operating according to the Dieselprinciple. It is to be understood, however, that the inventionis applicable for any kind of operating principle, such ase.g. internal combustion engines operating according to spark-ignition (ST), homogeneous charge compression ignition (HCCT),reactivity controlled compression ignition (RCCI), partiallypremixed combustion (PPC).
    Fig. 1A schematically depicts a powertrain of an exemplaryvehicle 100. The powertrain comprises a power source, in thepresent example a compression-ignited internal combustionengine 101 such as a Diesel engine, which, in a conventionalmanner, is connected via an output shaft, i.e. a crankshaft ofthe internal combustion engine 101, normally also utilising aflywheel 102, to a gearbox 103 via a clutch 106. An outputshaft 107 from the gearbox 103 propels drive wheels 113, 114via a final drive 108, such as a common differential, anddrive axles 104, 105 connected to said final drive 108.
    The internal combustion engine 101 is controlled by thevehicle control system via a control unit 115. The clutch 106and gearbox 103 are also controlled by the vehicle controlsystem by means of a control unit 116.
    Fig. 1A discloses a powertrain of a specific kind, but theinvention is applicable for any kind of powertrain, and also11e.g. in hybrid vehicles. The disclosed vehicle furthercomprises one or more aftertreatment components 130 foraftertreatment (purifying) of exhaust gases that results fromcombustion in the internal combustion engine 101. Thefunctions of the one or more aftertreatment components 130 arecontrolled by means of a control unit 131. It is to be notedthat the system described herein is only exemplary, and thataccording to embodiments of the invention, the vehicle is of akind where exhaust gases are not subject to aftertreatment.The vehicle may also be of a kind where no turbocharger isused.
    As is known to a person skilled in the art, aftertreatmentcomponents 130 may be of various kinds, designs andcombinations, and are not discussed more in detail herein.
    As was mentioned above, the present invention provides amethod for stopping the combustion engine that, at least insome instances, may provide advantages in comparison to othersolutions. For example, the time it takes to stop the internalcombustion engine can be reduced.
    An exemplary method 300 of the present invention is shown infig. 3. The method can be implemented at least partly e.g. inthe engine control unit 115 for controlling operation of theinternal combustion engine 101. The functions of a vehicleare, in general, controlled by a number of control units, andcontrol systems in vehicles of the disclosed kind generallycomprise a communication bus system consisting of one or morecommunication buses for connecting a number of electroniccontrol units (ECUs), or controllers, to various components onboard the vehicle. Such a control system may comprise a largenumber of control units, and the control of a specificfunction may be divided between two or more of them.12For the sake of simplicity, Fig. 1A depicts only control units115-116, 131, but vehicles 100 of the illustrated kind areoften provided with significantly more control units, as oneskilled in the art will appreciate. Control units 115-116, 131are arranged to communicate with one another and variouscomponents via said communication bus system and other wiring,partly indicated by interconnecting lines in fig. 1A.
    The present invention can be implemented in any suitablecontrol unit in the vehicle 100, and hence not necessarily inthe control unit 115. The control influencing valve openingand valve closing according to the present invention tocontrol reduction of pressure through valve opening followingcompression will usually depend on signals being received fromother control units and/or vehicle components, and it isgenerally the case that control units of the disclosed typeare normally adapted to receive sensor signals from variousparts of the vehicle 100. The control unit 115 may, forexample, receive signals from the control system requestingthe internal combustion engine 101 to be stopped.
    Control units of the illustrated type are also usually adaptedto deliver control signals to various parts and components ofthe vehicle, e.g. to control valves according to theinvention, e.g. by controlling phasers and/or switches ofcamshafts and/or to control fuel injection. Operation ofvehicle control systems per se is known to the person skilledin the art.
    Furthermore, control of this kind is often accomplished byprogrammed instructions. The programmed instructions typicallyconsist of a computer program which, when executed in acomputer or control unit, causes the computer/control unit toexercise the desired control, such as method steps accordingto the present invention. The computer program usually13constitutes a part of a computer program product, wherein saidcomputer program product comprises a suitable storage medium121 (see Fig. IB) with the computer program 126 stored on saidstorage medium 121. The computer program can be stored in anon-volatile manner on said storage medium. The digitalstorage medium 121 can, for example, consist of any of thegroup comprising: ROM (Read-Only Memory), PROM (ProgrammableRead-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM(Electrically Erasable PROM), a hard disk unit etc, and bearranged in or in connection with the control unit, whereuponthe computer program is executed by the control unit. Thebehaviour of the vehicle in a specific situation can thus beadapted by modifying the instructions of the computer program.
    An exemplary control unit (the control unit 115) is shownschematically in Fig. 1B, wherein the control unit cancomprise a processing unit 120, which can consist of, forexample, any suitable type of processor or microcomputer, suchas a circuit for digital signal processing (Digital SignalProcessor, DSP) or a circuit with a predetermined specificfunction (Application Specific Integrated Circuit, ASIC). Theprocessing unit 120 is connected to a memory unit 121, whichprovides the processing unit 120, with e.g. the stored programcode 126 and/or the stored data that the processing unit 120requires to be able to perform calculations. The processingunit 120 is also arranged so as to store partial or finalresults of calculations in the memory unit 121.
    Furthermore, the control unit 115 is equipped with devices122, 123, 124, 125 for receiving and transmitting input andoutput signals, respectively. These input and output signalscan comprise waveforms, pulses or other attributes that thedevices 122, 125 for receiving input signals can detect asinformation for processing by the processing unit 120. The14devices 123, 124 for transmitting output signals are arrangedso as to convert calculation results from the processing unit120 into output signals for transfer to other parts of thevehicle control system and/or the component (s) for which thesignals are intended. Each and every one of the connections tothe devices for receiving and transmitting respective inputand output signals can consist of one or more of a cable; adata bus, such as a CAN bus (Controller Area Network bus), aMOST bus (Media Oriented Systems Transport) or any other busconfiguration, or of a wireless connection.
    Returning to the exemplary method 300 illustrated in fig. 3,the method starts in step 301, where it is determined whetherthe internal combustion engine 101 is to be stopped. When thisis the case, the method continues to step 302. The methodremains in step 301 for as long as this is not the case, andthe method continues to step 302 when it is determined thatthe internal combustion engine is to be stopped according tothe invention. The transition from step 301 to step 302 can,for example, be initiated at all times when the internalcombustion engine is to be stopped. Alternatively, controlaccording to the invention can be arranged to be performede.g. only for particular situations when the internalcombustion engine is to be stopped, such as when the internalcombustion engine is to be stopped in a stop-start operation,or when the vehicle is urban areas where restrictionsregarding noise may apply, and/or anytime stopping of theinternal combustion engine is requested by the control systemand not the vehicle driver. Other criteria for performing thetransition from step 301 to step 302 may also be applied.
    In step 302 a suitable control of the reduction of pressurefollowing compression by opening of one or more valves whenstopping the internal combustion engine is determined, andaccording to the present example the reduction of pressurefollowing compression is controlled by controlling an exhaustvalve of a combustion chamber, and where, according to thepresent example, all combustion chambers are arranged to becontrolled in the same manner. Hence, in step 302 a suitablecontrol of the exhaust valves of the combustion chambers ofthe internal combustion engine is determined. According toother embodiments of the invention, intake valves arecontrolled instead, and according yet other embodiments of theinvention, both intake valves and exhaust valves arecontrolled to reduce the crankshaft propelling power inexpansion stages following upon compression stages. Accordingto embodiments of the invention, the control may bepredetermined, and hence automatically utilised when stoppingthe internal combustion engine 101. An exemplary control isdescribed below with reference to figs. 5A-B.
    The internal combustion engine 101 comprises a plurality ofcombustion chambers, e.g. 4, 5, 6 or 8. The present inventionmay be utilised for combustion engines having any number ofcombustion chambers, and an exemplary combustion chamber 209is shown in fig. 2. The figure hence discloses only onecylinder/combustion chamber 209 in which a reciprocatingpiston 210 is arranged.
    Internal combustion engines of the disclosed kind furthercomprises, in general, at least one fuel injector percombustion chamber (not shown) which in a conventional mannersupplies fuel to the combustion chamber for combustion.
    The combustion chamber 209 comprises an inlet 201 beingcontrolled by one or more intake valves 211, which may be, andis according to the present example, arranged to beindividually controlled in relation to an exhaust valve 213according to the below. Air for combustion is supplied to the16combustion chamber by means of the intake valve 211 through anintake conduit 402, e.g. consisting of suitable piping, tubingand/or hosing, for receiving the air for supply to thecombustion. In general, the air consists of air taken from theenvironment of the vehicle 100.
    Evacuation of the combustion chamber 209 is controlled throughan (or a plurality of) exhaust valve 213, which opens towardsan exhaust manifold 414.
    With regard to the exhaust valve 213 and intake valve 211these are, in the present example, controlled individually bymeans of camshafts 203, 204, respectively, which, althoughbeing commonly driven by a crankshaft 205, are arranged to beindividually phased in relation to each other so that openingtime, closing time and duration of the opening of the valves211, 213 can be individually controlled for each valve. Thephasing can, for example, be accomplished by means of phasers.Use of phasers allows continuous adjustment of the valvecontrol. For example, the phasers may be arranged such thateach camshaft can be phase shifted up to e.g. 60, 80 or 100crank angle degrees or any other suitable number of degrees,where phase shifting selectively can be e.g. both advancingand retarding, thereby allowing a relatively high degree offreedom when controlling the inlet valve and exhaust valve inrelation to each other.
    As an alternative, or in addition to, controlling the valvesby phasing, additional camshaft tappets may be utilised toobtain openings and closing of valves at piston positionswhere this otherwise is not carried out, and hence e.g. forother portions of a combustion cycle than during normaloperation, and also distinct from phasing. Such tappets may bearranged to be selectively engageable, e.g. by means ofswitches. An exemplary use of such additional valve opening is17illustrated by dashed line 505 in fig. 5 below. Tnstead ofusing camshaft controlled tappets, opening/closing of valvesmay also be arranged to be controlled in any suitable manner,such as by electrical and/or mechanical and/or pneumaticalITIGäHS .
    The system is also shown in fig. 4, which schematically showsall cylinders of the combustion engine, denoted i1-i6 in fig.4.
    According to the disclosed example, ambient air from thevehicle/engine surrounding is drawn trough an air filter 404from an intake side 404A of the air filter 404 being subjectedto ambient air and being drawn through the air filter 404 bymeans of a compressor 406. The compressor 406 is driven by aturbine 408, the compressor 406 and turbine 408 beinginterconnected by means of a shaft 410, thereby forming aconventional turbocharger. The compressed air is cooled by acharge air cooler 412 in a manner known per se prior to beingsupplied to the intake conduit 402 and combustion chambers il-i6 of the internal combustion engine 101.
    Passage to the exhaust conduits of the combustion chambers il-i6, is controlled by the exhaust valves of the combustionchambers, respectively. According to the present example, theexhaust conduits are further arranged such that exhaust gasesemanating from cylinders i1-i3 share a common conduit 414 fromexhaust outlets to a first inlet 408A of the turbine 408.Correspondingly, exhaust gases emanating from cylinders i4-i6share a common conduit 416, separate from the conduit 414,from exhaust outlets to a second inlet 408B of the turbine408. The turbine 408, consequently, comprises separate exhaustgas inlets for receiving the exhaust gas streams from conduits414 and 416, respectively, e.g. constituting a conventionaltwin-scroll turbine. Such arrangements may e.g. reduce18problems with pressure pulses consisting of exhaust from onecombustion chamber disturbing operation of another combustionchamber. This is not discussed further herein.
    The exhaust gas stream is then again combined and dischargedby the turbine 408 through a single common outlet 4080 and isled to the one or more aftertreatment components 130, possiblyvia e.g. an exhaust brake, for aftertreatment of exhaust gasesaccording to the above prior to being released into thesurroundings of the vehicle 100.
    As was mentioned above, a suitable control of the valves isdetermined in step 302, and figs. 5A-B shows an exemplarycontrol method that may be utilised according to theinvention. The y-axis represents state of the valve, where thezero level represents a fully closed valve, and the otherlevels at least partially open valve, where physically fullyopen occurs at the top of the curve, although the fully openposition in terms of flow may occur earlier. According to theinvention, the valves may be considered ”open” when they arenot fully closed, i.e. as soon as they have started to openand until they again are in closed position. The x-axisrepresent movement, expressed in crankshaft degrees and -360°,0°, 360°, representing piston 210 position top dead centreTDC, i.e. the piston being closest to valves 211, 213 prior tocommencing travel towards crankshaft 205. Solid line 501represents the intake valve 211, and dash/dotted line 502represent the exhaust valve 213. Dotted line 503 represents alimitation in valve clearance. That is, when intake and/orexhaust valves open inwards, and hence in a direction towardsthe piston 210 reciprocating in the combustion chamber 209,valves may not fully open at piston top dead centre TDC toavoid valves colliding with the piston. Dashed line 503represents this valve clearance which must not be violated,19hence according to the present embodiment, lines 501, 502 maynot intersect line 503. According to alternative embodiments,the piston head may, instead, be provided with valve cut-outsor recesses to allow further, or full, valve opening at TDC,e.g. according to dotted line 504. According to furtherembodiments of the invention, valves may be designed such thatvalves open in a manner that do not interfere with the pistonirrespective of when or the extent to which the valves open.
    Fig. 5A illustrates an example of normal valve operation whenthe internal combustion engine is running, i.e. a conventionalcombustion cycle where intake valve 211 open at approx. -360°for intake of air for combustion when the piston 210 travelsfrom TDC (at -360°) to bottom dead centre BDC at -180°.According to the present example, intake valve 211 closeswhen, or slightly after, the piston commences return stroketowards TDC at -180°. The return stroke from -180° to 0° (i.e.TDC) is the compression stage, or stroke in the presentexample, and around 0° fuel is injected into the compressedair to commence combustion as is known per se.
    The resulting compression, i.e. the pressure obtained duringthe compression stroke, depends on the amount of air providedduring the intake stroke, which in turn depends, inter alia,on the pressure of the intake air delivered by the compressor412. When the engine is running, the force acting on thepiston in the following expansion stage, stroke in this case,depends partly on the pressure obtained during the compressionstage, where the work produced by gas expansion is increasedby the combustion.
    In the general case, when the engine is to be turned off,intake valves and exhaust valves are operated in aconventional manner but fuel injection is turned off to stopthe engine. The compression in the compression stage aids thestopping of the engine by retarding the crankshaft 112, butthe following expansion stage provides a force acting on thepiston 210, albeit less than when combustion is occurring,which in turn propels the crankshaft and hence counteracts thestopping of the engine. Due to losses and generation of heatduring compression the propelling force exerted duringexpansion is lower than the retarding force resulting fromcombustion and the engine in general stops in a relativelyshort period of time.
    According to the invention, the time it takes to stop theinternal combustion engine is substantially reduced byreducing or eliminating the propelling force caused byexpansion. According to the exemplary embodiment, this isaccomplished by opening, at least to some extent, the exhaustvalve at the end of compression and/or at the beginning of theexpansion. As is realised, it is preferred to open the exhaustvalve as late as possible during the compression stage tobenefit as much as possible from the retarding force caused bycompression.
    The opening of the exhaust valve can be controlled, forexample, by suitable phasing of the camshaft controlling theexhaust valve 213, and this phasing can be determined in step302. An exemplary phasing suitable for use during stop of theinternal combustion engine is shown in fig. 5B, where theintake valve 211 is controlled according to the above fornormal intake of air, but where, in this example, the exhaustvalve 213, in addition to conventional evacuation of thecombustion chamber in an exhaust stroke (dash-dotted line infig. 5A), opens partly at the end of the compression stage andis maintained in the beginning of the expansion stage, dashedline 505. As can be seen from fig. 5B, the exhaust valve 213open to an extent respecting the available valve clearance,21where other designs may allow further/full opening of thevalve. In this way, the compression stage is utilised to alarge extent to retard the crankshaft, but when the exhaustvalve 213 opens, the compressed gas in the combustion chamberwill expand through the exhaust valve 213 into the exhaustmanifold 414. In this way, the expansion of the pressured gaswill in little or no extent provide a force to assist thepiston 210 when moving towards BDC, and hence the reduction inpropelling force will substantially reduce the time it takesfor the internal combustion engine 101 to stop. Preferably aplurality of, or all of, the combustion chambers il-i6 of theinternal combustion engine 101 are controlled in this manner.
    When a suitable control has been determined in step 302, e.g.according to fig. 5B or any other suitable control forreducing crankshaft propulsion by expansion, the methodcontinues to step 303.
    In step 303 fuel injection is turned off, and in step 304 theexhaust valve 213 is controlled by the determined control, inthis case by suitable phasing of the camshaft 204, wherevalves of all combustion chambers may simultaneouslycontrolled in the same manner, e.g. by camshaft 204.
    In step 305 it is determined whether the internal combustionengine is stopped, i.e. the speed of rotation of thecrankshaft 205 has reached zero, and for as long as this isnot the case, valve control according to the above iscontinued. When it is determined that the internal combustionengine has been stopped, the method ends in step 306.
    According to exemplary embodiments of the invention, valvecontrol according to the invention is maintained until thespeed of rotation has been at least reduced to a first speedof rotation nl, such as e.g. 10 or 50 rpm, where valve controllO22may be returned to normal valve control at the very end of thestopping of the internal combustion engine to be set for afollowing start of the internal combustion engine, while stillbenefitting substantially from the present invention.
    According to the present example, the exhaust valve 2l3 ismaintained open during part of the expansion stage, i.e. fromO° and onwards. This may be beneficial e.g. to avoid or reducethe below atmospheric pressure that otherwise may arise if thecombustion chamber is closed at atmospheric pressure at TDCand the combustion chamber volume then expands as the pistontravels towards BDC. If the pressure becomes too low in thecombustion chamber, oil may be drawn into the combustionchamber past the piston/cylinder wall, which may bedetrimental to the operation of the internal combustionengine. Hence the valve control can be determined to take thisfactor into account.
    Furthermore, according to the present example, the exhaustvalves of the combustion chambers are controlled, butaccording to embodiments of the invention, the intake valvesmay be controlled instead, e.g. by suitable phasing ofcamshaft 203. According to embodiments of the invention bothintake valves and exhaust valves may be controlled in asuitable manner, such as e.g. exhaust valve at the end ofcompression stage and intake valve at the beginning of theexpansion stage, or vice versa.
    Furthermore, in case of 4-stroke internal combustion engines,the procedure described above may be used twice for eachcombustion cycle, i.e. intake of air may be carried out notonly during the normal intake stage as above, but this mayalso be repeated with intake at the expansion stage, i.e.valve does not close again as in fig. 5B but maintained openfor a longer period of time, followed by a control duringlO23evacuation stage similar to the above where the exhaust valveis opened e.g. according to the above instead of as in theconventional manner.
    Hence, according to the invention, a method of stopping theinternal combustion engine is provided, which imposesconsiderable improvements regarding the time it takes to stopthe engine. This also means that noise from the engine isreduced since the time during which the engine makes sound isreduced.
    In addition to the above, the present invention may further beused in combination with the solution described in the Swedishpatent application l65lO44-8, with the title ”METHOD ANDSYSTEM FOR STARTING AN INTERNAL COMBUSTION ENGINE", With thesame filing date and applicant as the present application.
    This application relates to situations where it may bedesirable to start the internal combustion engine in a mannerthat reduces wear on internal combustion engine componentsand/or e.g. a starter motor. The disclosed method may be usede.g. in start-stop solutions, and be utilised in vehicleswhere the internal combustion engine is stopped according tothe present invention.
    Finally, the present invention has been exemplified for avehicle. The invention is, however, applicable in any kind ofcraft, such as, e.g., aircrafts and watercrafts. The inventionis also applicable for use in combustion plants. Also, theinvention is applicable for any kind of internal combustion,and not only where a piston is reciprocating in a combustionchamber, but also for other kinds of engines, such as e.g.Wankel engines, for as long as compression is performed aspart of a combustion cycle.
    权利要求:
    Claims (1)
    [1] 24 Claims ld Method for stopping an internal combustion engine (101), said internal combustion engine (101) having at least onecombustion chamber (209) and a crankshaft (112) beingarranged to be propelled by said at least one combustionchamber (209), wherein intake of gas to said at least onecombustion chamber (209) is controlled by at least oneintake valve (211), and wherein evacuation of said atleast one combustion chamber (209) is controlled by atleast one exhaust valve (213), the method beingcharacterised in, when said internal combustion engine(101) is to be stopped: - turning off fuel injection, - with fuel injection turned off, controlling an intakevalve (211) and/or an exhaust valve (213) of said atleast one combustion chamber (209) such that, followingcompression in said at least one combustion chamber(209), pressure in said combustion chamber (209) isreduced to reduce a crankshaft (112) propelling power caused by gas expansion following said compression. .Method according to claim 1, further including: - controlling an intake valve (211) and/or exhaust valve(213) of said combustion chamber (209) to reducecrankshaft (112) propelling power caused by expansionfollowing compression until the speed of rotation of saidcrankshaft (112) is reduced to at least substantially ZGKO. .Method according to claim 1 or 2, further including: - reducing said pressure following compression by controlling said intake valve (211) and/or exhaust valve (213) such that pressure is reduced to essentially atmospheric pressure. .Method according to any one of claims 1-3, further including: - prior to said compression, opening an intake valve(211) and/or exhaust valve (213) of said combustionchamber (209) for intake of gas, and - following compression of said intake of gas, opening anintake valve (211) and/or exhaust valve (213) of saidcombustion chamber (209) to reduce pressure in saidcombustion chamber (209) to thereby reduce crankshaft(112) propelling power caused by gas expansion inrelation to the crankshaft (112) propelling power otherwise obtained. .Method according to any one of claims 1-4, further including: - when reducing compression in said combustion chamber (209), opening an intake valve (211) and/or an exhaust valve (213) at the end of the compression and/or at the beginning of the following expansion. .Method according to any one of the claims 1-5, further including: - controlling an intake valve (211) and/or an exhaustvalve (213) to reduce said compression by phasing of atleast one camshaft, or part thereof, to thereby controlopening and/or closing of an intake valve (211) and/orexhaust valve (213) in dependence of the current positionof a reciprocating member (210) in said combustionchamber (209), said dependency being controllable using said phasing. 10. 11. 26 .Method according to any one of the claims 1-6, wherein opening and closing of intake valves (211) are controlledby a first camshaft (203), and wherein opening andclosing of exhaust valves (213) are controlled by asecond camshaft (204), the method further including: - individually phasing at least one of said first (203)and second (204) camshaft to control reduction ofpressure following compression in said combustion chambers (209). .Method according to any one of the claims 1-7, further including: - reducing pressure in said combustion chamber (209)following compression by opening an intake valve (211)and/or an exhaust valve (213) during a period of anexpansion stroke where said valves are closed when said internal combustion engine (101) is running. .Method according to claim 8, said period being a crankshaft (112) rotation, e.g. determined in crank angle degrees. Method according to any one of the claims 1-9, whereinintake of gas to said combustion chamber (209) iscontrolled by two or more intake valves (211), and/orwherein evacuation of said combustion chamber (209) iscontrolled by two or more exhaust valves (213), themethod further including: - controlling at least one of said valves to reducepressure in said combustion chamber (209) followingexpansion to reduce crankshaft (112) propelling power caused by gas expansion following compression. Method according to any one of the claims 1-10, the internal combustion engine (101) including a plurality of 12. 13. 14. 15. 27 combustion chambers (209), the method further including:- controlling a plurality of combustion chambers (209) ofsaid internal combustion engine (101) such that followingcompression in said combustion chambers (209), pressurein said combustion chambers (209) is reduced to reducecrankshaft (112) propelling power caused by gas expansion following said compression. Method according to any one of the claims 1-11, furtherincluding, when stopping said internal combustion engine(101): - increasing the load on said internal combustion engine(101) by increasing power consumption of one or moreloads being driven by said internal combustion engine (101). Computer program comprising program code that, when saidprogram code is executed in a computer, causes saidcomputer to carry out the method according to any of claims 1-12. Computer program product comprising a computer-readablemedium and a computer program according to claim 13,wherein said computer program is contained in said computer-readable medium. System for stopping an internal combustion engine (101),said internal combustion engine (101) having at least onecombustion chamber (209) and a crankshaft (112) beingarranged to be propelled by said at least one combustionchamber (209), wherein intake of gas to said at least onecombustion chamber (209) is controlled by at least oneintake valve (211), and wherein evacuation of said atleast one combustion chamber (209) is controlled by at least one exhaust valve (213), the method being lO 28 characterised in, when said internal combustion engine(lOl) is to be stopped: - means adapted to turn off fuel injection, - means adapted to, when fuel injection is turned off,control an intake valve (2ll) and/or an exhaust valve(2l3) of said at least one combustion chamber (209) suchthat, following compression in said at least onecombustion chamber (209), pressure in said combustionchamber (209) is reduced to reduce a crankshaft (ll2)propelling power caused by gas expansion following said compression. l6.Vehicle, characterised in that it comprises a system according to claim l5.
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    同族专利:
    公开号 | 公开日
    SE542314C2|2020-04-07|
    BR112018075612A2|2019-04-09|
    DE112017002863T5|2019-02-28|
    WO2018013041A1|2018-01-18|
    引用文献:
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    US7506625B2|2006-03-31|2009-03-24|Caterpillar Inc.|Method and apparatus for controlling engine valve timing|
    JP2009024660A|2007-07-23|2009-02-05|Hino Motors Ltd|Cranking vibration reduction device|
    DE102008008117A1|2008-02-08|2009-08-13|Schaeffler Kg|Method for adjusting a camshaft of an internal combustion engine and internal combustion engine with an adjustable camshaft|
    GB2476435B|2008-10-23|2013-01-09|Univ Brunel|Method of starting an internal combustion engine|
    DE102013020780A1|2013-12-11|2015-06-11|Daimler Ag|Phase adjustment device for a valve train|
    JP5994803B2|2014-03-14|2016-09-21|アイシン精機株式会社|Vehicle control device|EP3788244A1|2018-05-04|2021-03-10|Wärtsilä Finland Oy|A method for starting a four-stroke reciprocating internal combustion piston engine and a four-stroke reciprocating internal combustion piston engine|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1651045A|SE542314C2|2016-07-12|2016-07-12|Method and system for stopping an internal combustion engine|SE1651045A| SE542314C2|2016-07-12|2016-07-12|Method and system for stopping an internal combustion engine|
    DE112017002863.9T| DE112017002863T5|2016-07-12|2017-07-06|Method and system for stopping an internal combustion engine|
    PCT/SE2017/050758| WO2018013041A1|2016-07-12|2017-07-06|Method and system for stopping an internal combustion engine|
    BR112018075612-1A| BR112018075612A2|2016-07-12|2017-07-06|method and system for stopping an internal combustion engine|
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