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`EXHIBIT S
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`Case 1:17-cv-00770-JDW-MPT Document 120-6 Filed 11/17/22 Page 2 of 10 PageID #:
`13168
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`(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2009/0118912 A1
`Hugenroth et al.
`(43) Pub. Date:
`May 7, 2009
`
`US 200901 18912A1
`
`(54) ENGINE CONTROL SYSTEM OF A
`SELF-PROPELLED WORKING MACHINE
`
`(76) Inventors:
`
`Ludger Hugenroth, Ostbevern
`(DE); Thomas Zegota,
`Harsewinkel (DE); Michael
`Haverkamp, Ostbevern (DE);
`Jan-Willem Verhorst, Lippsatdt
`(DE)
`
`Correspondence Address:
`Striker, Striker & Stenby
`103 East Neck Road
`Huntington, NY 11743 (US)
`
`(21) Appl. No.:
`
`12/261,178
`
`(22) Filed:
`
`Oct. 30, 2008
`
`(30)
`
`Foreign Application Priority Data
`
`Nov. 7, 2007 (DE) ...................... 10 2007 O53. 436.3
`
`
`
`Publication Classification
`
`(51) Int. Cl.
`(2006.01)
`B60V I/06
`(2006.01)
`G06F 7700
`(2006.01)
`B60V I/O
`(52) U.S. Cl. .............................. 701/50, 701/102; 701/54
`(57)
`ABSTRACT
`In an engine control system of a self-propelled working
`machine, a method for operating an engine control system of
`this type, and a self-propelled working machine equipped
`with at least one drive engine—the rotational speed of which
`may be regulated—and working units that are driven in Such
`a manner that their rotational speeds are adjustable, with
`which the engine speed is regulated as a function of the load
`on the drive engine(s), and the at least one drive engine is
`coupled with one or more working units via a drive train, the
`drive train includes at least one gearbox stage that holds the
`drive speed of the working unit(s) constant, and the at least
`one gearbox stage is designed as a mechanical-mechanical
`power-split transmission. Thereby the drive engine may be
`operated in a fuel-saving rotational speed range without this
`affecting the working speeds of the working units.
`
`15
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`Patent Application Publication
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`May 7, 2009
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`Sheet 1 of 3
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`US 2009/0118912 A1
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`Patent Application Publication
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`May 7, 2009 Sheet 2 of 3
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`US 2009/0118912 A1
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`Patent Application Publication
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`May 7, 2009 Sheet 3 of 3
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`US 2009/0118912 A1
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`Case 1:17-cv-00770-JDW-MPT Document 120-6 Filed 11/17/22 Page 5 of 10 PageID #:
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`DMXT
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`US 2009/01 18912 A1
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`May 7, 2009
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`ENGINE CONTROL SYSTEM OF A
`SELF-PROPELLED WORKING MACHINE
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`0001. The invention described and claimed hereinbelow is
`also described in German Patent Applications DE 10 2007
`053. 436.3 filed on Nov. 7, 2007. This German Patent Appli
`cation, whose Subject matter is incorporated here by refer
`ence, provides the basis for a claim of priority of invention
`under 35 U.S.C. 119(a)-(d).
`
`BACKGROUND OF THE INVENTION
`0002 The present invention relates to an engine control
`system of a self-propelled working machine, a method for
`operating an engine control system of this type, and an appli
`cation of this engine control system in a method.
`0003 Publication DE 38 10724 makes known an engine
`control system that is designed to ensure that—when the drive
`engine is operated in a partial load range at a lower engine
`speed in order to save fuel—the working units always operate
`at a constant rotational speed, regardless of whether the drive
`engine is operated at a higher or lower engine speed. In a first
`embodiment, publication DE 38 10724 proposes a structure
`in which a torque converter is assigned to each working unit
`in a decentralized manner, thereby making it possible to adapt
`every working unit to the changed engine speed in an indi
`vidualized manner. In addition to the high costs required to
`include the decentralized torque converters, a complex con
`trol system is also required, since every working unit must be
`monitored separately and controlled in a defined manner.
`0004 For this reason, the document proposes in a fur
`ther embodiment—to provide a single, centralized transmis
`sion block, which is located directly in the drive train between
`the drive engine and the large number of working units, i.e.,
`the consumers, and to immediately adapt the rotational speed
`of the drive train to the changed engine speed using a suitable
`electronic control device. In this case, the central transmis
`sion is designed as a power shift transmission. A design of this
`type has the advantage that the working units do not need to be
`decoupled during the shifting process. Due to the limited
`Switching stages of a power shift transmission, the engine
`speed may be changed only in a limited manner.
`0005. In contrast, publication EP 1609349 discloses an
`engine-speed control device, with which the output shaft of
`the drive engine is coupled directly with the Sun gear of a
`planetary gear set, while a hydromotor coupled with an inter
`nal gear brings about a change in the rotational speed of the
`output shaft of the planetary gear set. By coupling the plan
`etary gear set directly with the drive engine and a hydraulic
`drive, the structure of a hydraulic-mechanical power-split
`transmission is obtained, the efficiency of which is markedly
`lower than that of a purely mechanical energy transmission,
`due to the power losses that occur in the hydraulic branch. As
`a result, the drive engine must be operated in a torque range
`that regularly also requires a higher nominal speed range of
`the drive engine, which ultimately results in higher fuel con
`Sumption.
`
`SUMMARY OF THE INVENTION
`0006. The object of the present invention, therefore, is to
`avoid the described disadvantages of the related art and, in
`particular, to provide an engine control system for self-pro
`
`pelled working machines that results in an optimal operation
`of a drive engine with low fuel consumption.
`0007. In keeping with these objects and with others which
`will become apparent hereinafter, one feature of the present
`invention resides, briefly stated in an engine control system of
`a self-propelled working machine with at least one drive
`engine—the rotational speed of which may be regulated—
`and working units that are driven in Such a manner that their
`rotational speeds are adjustable, and with which the engine
`speed is regulated as a function of the load on the drive
`engine(s), and the at least one drive engine is coupled with
`one or more working units via a drive train, and the drive train
`includes at least one gearbox stage that holds the drive speed
`of the working unit(s) constant, wherein the at least one
`gearbox stage (24) is designed as a mechanical-mechanical
`power-split transmission (25).
`0008 Another feature of the present invention resides in a
`method for operating an engine control system of a self
`propelled working machine with at least one drive engine—
`the rotational speed of which may be regulated—and working
`units that are driven in Such a manner that their rotational
`speeds are adjustable, and with which the engine speed is
`regulated as a function of the load on the drive engine(s), and
`the at least one drive engine is coupled with one or more
`working units via a drive train, and the drive train includes at
`least one gearbox stage that holds the drive speed of the
`working unit(s) constant, wherein the engine control system
`holds the engine speed (nmot) of the at least one drive engine
`(14) constant until a power requirement threshold (55) is
`reached and, when this power requirement threshold (55) is
`exceeded, a shift to the next engine speed stage (nmot1.
`nmot2) takes place.
`0009 Given that the engine control system of a self-pro
`pelled working machine is coupled with at least one drive
`engine—the rotational speed of which may be regulated—
`and working units that are driven in Such a manner that their
`rotational speeds are adjustable, and that are coupled with the
`drive engine via a drive train, and given that the drive train
`includes at least one gearbox stage that holds the drive speed
`of the working unit(s) constant due to the fact that the at least
`one gearbox stage is designed as a mechanical-mechanical
`power-split transmission, it is ensured that the drive engine
`may be operated in a fuel-saving speed range without this
`affecting the working speeds of the working units.
`0010. In an advantageous embodiment of the present
`invention, the input shaft of the gearbox stage is coupled with
`the output shaft of the at least one drive motor, and the output
`shaft of the gearbox stage is coupled with the drive train of at
`least one working unit; a change in the engine speed results in
`a change in the rotational speed of the output shaft of the
`gearbox stage, and the rotational speed of the output shaft of
`the gearbox stage is adapted within a rotational speed range in
`a stepless manner. An embodiment of this type has the advan
`tages, in particular, that the output speed of the output shaft of
`the gearbox stage may be held constant across a large engine
`speed range, and that the engine speed may be changed in any
`speed stage.
`0011. An embodiment of the steplessly variable, mechani
`cal-mechanical power-split transmission that is technically
`simple to realize is obtained when the power-split transmis
`sion includes a pulling-means gearbox for transferring at a
`constant rotational speed—a component of the drive power,
`and a continuously variable transmission for transferring—at
`variable rotational speeds—a further component of the drive
`
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`power, the power components being combined in a Summing
`transmission of the mechanical-mechanical power-split
`transmission. A high level of functional reliability of the
`gearbox stage is advantageously attained by using proven
`transmission structures, namely that the pulling-means gear
`box is designed as a belt drive, the continuously variable
`transmission is designed as a variator drive, and the Summing
`transmission is designed as a planetary gear set.
`0012. A very compact embodiment that requires few
`transmission components results when the pulley of the pull
`ing-means gearbox assigned to the output shaft of the trans
`mission is non-rotatably connected with the internal gear of
`the planetary gear set, and the variator disk of the variator
`transmission assigned to the output shaft of the transmission
`is non-rotatably connected with the planet carrier—on which
`the planetary gears are mounted—of the planetary gear set,
`and when the further pulley of the pulling-means gearbox and
`the further variator disk of the variator transmission are non
`rotatably coupled with the output shaft of the at least one drive
`motor. In this manner, a separate transmission input shaft and
`intermediate transmission elements become unnecessary.
`0013 From the perspective of prefabricating modules, it
`may be advantageous, however—according to an advanta
`geous refinement of the present invention for the further
`pulley of the pulling-means gearbox—which is non-rotatably
`coupled with the output shaft of the at least one drive
`engine—and for the further variator disk of the variator trans
`mission to be non-rotatably connected—via an input shaft
`assigned to a gearbox stage—with the output shaft of the at
`least one drive engine. In this manner, the inventive transmis
`sion may be prefabricated as a separate assembly indepen
`dently of the other components.
`0014) To enable the adjustment of the engine speed to be
`carried out in a largely automated manner, it is provided in a
`further advantageous embodiment of the present invention
`for a control and regulating unit to be provided that ascertains
`the power requirement of the drive train and/or the working
`units and, with consideration for the engine characteristics,
`the fuel-consumption characteristics of the drive engine(s),
`and the required engine output, implements an engine speed
`in the partial-load range with the lowest specific fuel con
`Sumption.
`0015. In the simplest case, a nearly constant output speed
`of the output shaft of the gearbox stage is attained by lowering
`or raising the rotational speed of the output shaft of the at least
`one gearbox stage in the same ratio by which the engine speed
`is raised or lowered.
`0016 Depending on the amount of installation space
`available and the distances to be bridged between the drive
`engine and the working units, it may be provided in a further
`advantageous embodiment of the present invention that the
`power-split transmission includes a pulling-means gearbox
`designed as a toothed gearset for transferring—at a constant
`rotational speed—a component of the drive power, and a
`continuously variable transmission designed as a chain
`torque converter for transferring at variable rotational
`speeds—a further component of the drive power, the power
`components being combined in a Summing transmission of
`the power-split transmission.
`0017. It is also feasible for a continuously variable trans
`mission for adjusting rotational speed to be assigned to each
`working unit, so that each working unit may be adapted to the
`
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`change in engine speed in an individualized manner, thereby
`ultimately eliminating the need for a cost-intensive Summing
`transmission.
`0018. Given that the engine control system holds the
`engine speed of the at least one drive engine constant until a
`power requirement threshold value is reached and, when this
`power requirement threshold is exceeded, switches to the next
`engine speed stage, it is ensured that a nearly constant output
`speed at the output shaft of the gearbox stage is maintained
`using a minimum number of speed changes.
`0019. To ensure that the drive engine never stalls, even
`when brief peak loads occur at the various working units, it is
`provided in an advantageous embodiment of the present
`invention that the power requirement threshold value is below
`the regulating characteristic of the particular drive engine.
`The power requirement threshold value is preferably approxi
`mately 20% lower than the regulating characteristic of the
`particular drive engine.
`0020 Depending on whether the drive engine is under
`loaded or overloaded at its momentary operating point, it is
`provided in an advantageous embodiment of the present
`invention that a Switch is made to a higher or lower engine
`speed—depending on the power requirement—when the
`power requirement threshold value is reached. The changes in
`engine speed and, therefore, the rotational speed of the con
`tinuously variable transmission, are advantageously carried
`out via the engine control unit and/or the control and regulat
`ing unit.
`0021. To ensure in an advantageous embodiment of the
`present invention that the efficiency of the entire usable
`engine speed range is as high as possible, the power compo
`nent of the continuously variable transmission decreases as
`the engine speed increases.
`0022. The novel features which are considered as charac
`teristic for the present invention are set forth in particular in
`the appended claims. The invention itself, however, both as to
`its construction and its method of operation, together with
`additional objects and advantages thereof, will be best under
`stood from the following description of specific embodiments
`when read in connection with the accompanying drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0023 FIG. 1 shows an inventive self-propelled working
`machine designed as a combine harvester.
`0024 FIG. 2 shows a schematic illustration of the inven
`tive drive train structure.
`0025 FIG.3 shows an illustration of the inventive method
`based on an engine characteristic diagram.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`0026 FIG. 1 shows a self-propelled working machine 1
`designed as a combine harvester 2, which includes—in a
`manner known perse—a grain-cutting device 3 located on the
`front, which is used to harvest and convey crop material 4. To
`process crop material 4, combine harvester 2 includes highly
`diverse working units 5, which include, in the exemplary
`embodiment shown, a threshing part 7 composed of one or
`more cylinders 6 that are partially enclosed by concaves 8, a
`separating device 10 that is located downstream of threshing
`part 7 and is designed as a tray-type shaker 9, and a cleaning
`device 11 assigned to separating device 10 on the underside.
`While threshing part 7 and/or separating device 10 may be
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`US 2009/01 18912 A1
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`May 7, 2009
`
`designed as axial rotors—which are known perse and are not
`shown here—, cleaning device 11 is typically composed of
`several oscillating sieve levels 12 and a cleaning fan 13
`assigned thereto.
`0027 Combine harvester 2 also includes at least one drive
`engine 14, which supplies—via a drive trainstructure 15 to be
`described in greater detail—the drive energy to working units
`5 and a ground drive 16 which is not described in greater
`detail—to drive land wheels 17 of front axle 18 and/or land
`wheels 19 of rear axle 20. Working units 5, which are also
`driven by drive engine 14, also include grain-cutting device 3.
`and feed rake unit 21 of a feed rake 22 located upstream of
`threshing part 7.
`0028 FIG. 2 provides a more detailed description of the
`present invention based on a schematic illustration of drive
`train structure 15. Gearbox stage 24 which is designed as a
`mechanical-mechanical power-split transmission 25 and will
`be described in greater detail below—is assigned to output
`shaft 23 of the at least one drive engine 14. Mechanical
`mechanical power-split transmission 25 includes a pulling
`means gearbox 26, a variator drive 27, and, on the outputside,
`a planetary gear set 28 mounted on an intermediate shaft 29.
`Output shaft 30 of gearbox stage 24 is non-rotatably con
`nected with Sun gear 31 of planetary gear set 28.
`0029. A pulley 32 of pulling-means gearbox 26 is non
`rotatably connected with output shaft 23 of drive engine 14.
`Pulley 34—which guides pulling means 33 designed as a
`composite belt—of pulling-means gearbox 26 is non-rotat
`ably connected with internal gear 35 of planetary gear set 28.
`Pulling-means gearbox 26 therefore transfers its power com
`ponent which it obtains from drive motor 14—directly to
`internal gear 35 of planetary gear set 28. It is within the scope
`of the present invention for the outer contour of internal gear
`35 to be designed directly as pulley 34. In addition, a pulley 36
`of variator drive 27 is non-rotatably assigned to output shaft
`23 of drive engine 14. Further pulley 37 of variator drive 27 is
`non-rotatably connected with intermediate shaft 29 of inven
`tive gearbox stage 24, which is simultaneously coupled in a
`non-rotatable manner with planet carrier 39 that accommo
`dates planetary gears 38, thereby enabling the power compo
`nent of drive engine 14 transmitted via composite V-belt 40 of
`variator drive 27 to be transmitted directly via planetary gears
`38 to sun gear 31 and, therefore, to output shaft 30 of inventive
`gearbox stage 24.
`0030 Gearbox stage 24 is therefore designed such that it
`introduced—via pulling-means gearbox 26—a power com
`ponent of drive engine 14 with engine speed nmot into plan
`etary gear set 28, which serves as a Summing transmission 42,
`while variator drive 27, which acts as continuously variable
`transmission 43, may vary the power component of drive
`engine 14 that was introduced into planetary gear set 28 at
`rotational speed nvar. Given that internal gear 35 of planetary
`gear set 28 engages with planetary gears 38, and that plan
`etary gears 38 engage with Sun gear 31, the rotational speed
`nab of output shaft 30 of gearbox stage 24 may be adjusted
`such that output shaft 30 of gearbox stage 24 always rotates at
`a constant rotational speed nab, independently of the change
`in engine speed nmot, and the engine output is ultimately
`transmitted mechanically. This is made possible by the fact
`that variator drive 27 may change variator speed invar in a
`stepless manner within a certain range.
`0031. It is within the scope of the present invention for
`pulleys 32.36 assigned to drive motor 14 to be non-rotatably
`located—as described—directly on output shaft 23 of drive
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`engine 14, or, in another embodiment, for pulleys 32.36 to be
`located on an input shaft 41 of gearbox stage 24. In the latter
`case, input shaft 41 of gearbox stage 24 is non-rotatably
`connected with output shaft 23 of drive engine 14.
`0032 FIG.2 shows a schematic design of drive trainstruc
`ture 15, which connects the output shaft of inventive gearbox
`stage 30 with various working units 5 of self-propelled work
`ing machine 1. In a manner known perse, drive trainstructure
`15 may include mechanical, hydraulic, and/or electrical
`energy-transmission elements for driving various working
`units 5. In the exemplary embodiment shown, which is a
`combine harvester 2, the various working units 5 include
`grain-cutting device 3, feed-rake device 21, threshing parts 7.
`separating device 10, cleaning device 11, and ground drive
`16. It is within the scope of the present invention for further
`working devices not described here, e.g., a straw-chopping
`and distributing device, to be present.
`0033. The at least one drive engine 14 includes an engine
`control unit 44, which communicates with a control and regu
`lating device 45 assigned to self-propelled working machine
`1. In a manner known per se, a torque sensor 46, which is
`known perse, may be assigned to each of the working units 5.
`Torque sensor 46 generates a power requirement signal Zand
`transmits it to control and regulating unit 45. It is within the
`Scope of the present invention to provide fewer torque sensors
`46—in order to lower costs—for determining the power
`requirement of agricultural working machine 1. In the sim
`plest case, a single torque sensor 46 for determining the total
`power requirement of combine harvester2 is assigned to drive
`train structure 15.
`0034. Depending on the design of engine control unit 44
`assigned to drive engine 14 and of control and regulating unit
`45 assigned to combine harvester 2, engine characteristics 47
`are stored in engine control unit 44 and/or control and regu
`lating unit 45, as are fuel-consumption characteristics 48 as a
`function of engine output Pmot and the specific fuel con
`Sumption. Control and regulating unit 45 also includes a
`program module 49, which determines—based on power
`requirement signals Z, and with consideration for engine
`characteristics 47 and fuel consumption characteristics
`48 an engine speed nmot for operating the at least one drive
`motor 14 that results in an optimal Supply of drive energy to
`working units 5 while ensuring low fuel consumption. This
`optimized engine speed nmot is transmitted via a control
`signal Y to engine control unit 44, which then regulates the
`fuel Supply Such that the optimal engine speed nmot that was
`determined is implemented at output shaft 23 of drive engine
`14, thereby enabling the drive engine to be operated at an
`operating point 51 located in partial load range 50.
`0035) To ensure that, when engine speed nmot changes,
`output speed nab at output shaft 30 of inventive gearbox stage
`24 remains constant, variator speed invar must now be
`increased in the same ratio by which engine speed nmot is
`reduced, or conversely, variator speed invar must be lowered in
`the same ratio by which engine speed nmot is increased. In a
`preferred embodiment, this may be realized by assigning
`speed sensors 52—which are known perse and are therefore
`not described in greater detail to output shaft 23 of drive
`engine 14, intermediate shaft 29, and output shaft 30 of
`mechanical-mechanical power-split transmission 25. Speed
`sensors 52 generate speed signals X and transmit them to
`control and regulating device 45. In control and regulating
`device 45, speed signals X are used to determine variator
`speed W, which is transmitted to controlling device 53 of
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`May 7, 2009
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`variator drive 27, which then opens or closes particular pulley
`36.37, thereby changing variator speed invar in Such a manner
`that a nearly constant output speed nab exists at output shaft
`30 of gearbox stage 24.
`0036. It is also within the scope of the present invention for
`mechanical-mechanical power-split transmission 25 to
`include a toothed gearset—which is not shown instead of
`pulling-means gearbox 26. It is also feasible to use, instead of
`the variator drive, a chain torque converter, which is known
`perse and is therefore not described here in detail, in order to
`obtain the effects described here, i.e., changing engine speed
`nmot while holding output speed nab at output shaft 30 of
`inventive gearbox stage 24 nearly constant. Mechanical-me
`chanical power-split transmission 25 may also have a decen
`tralized design Such that at least one continuously variable
`transmission 43 is assigned to particular working unit 5 in a
`decentralized manner. This would have the advantage that a
`Summing transmission 42 would be eliminated, and the varia
`tor drives of working units 5 which are present anyway—
`could be used to adjust rotational speed in an individualized
`manner. In addition, with an embodiment of this type, a
`continuously variable transmission 43 and related speed
`monitoring and regulating devices would have to be provided
`for each working unit 5.
`0037. When self-propelled working machine 1 is driven
`on the road, all working units 5 except for ground drive 16 are
`typically out of operation. In this case, it may also be pro
`vided, in a further embodiment, for variator speed invar to be
`tapped directly at intermediate shaft 29 of gearbox stage 24 in
`order to drive the not-shown pump of ground drive 16, and to
`increase the rotational speed of the Supply pump of ground
`drive 16 such that a sufficient output of the pump is ensured
`even when engine speed nmot is low.
`0038 FIG. 3 describes the inventive method based on a
`detailed illustration of an engine map. The diagram shows—
`as a function of engine output Pmot and engine speed nmot—
`an engine characteristic 47—regulating characteristic 54 in
`this case—and a large number of fuel-consumption charac
`teristics 48. In this case, the fuel consumption of fuel-con
`Sumption characteristic increases from 48a to 48m. According
`to the inventive method, it is provided that engine speed nmot
`of the at least one drive engine 14 remains constant in a first
`engine speed stage inmot1 until a power requirement thresh
`old value 55 is reached and, when power requirement thresh
`old value 55 is exceeded, a switch is made to the next engine
`speed stage inmot2.
`0039. Depending on the power requirement of drive ele
`ments 5 of self-propelled working machine 1, drive motor 14
`depicted in FIG. 3 is operated at an operating point 51 at
`engine speed nmot 1. If the power requirement of working
`units 5 increases—due, e.g., to a higher crop-material
`throughput to be processed by working units 5 of a combine
`harvester 2, or due to a rising incline of a territory to be
`traveled across—operating point 51 of drive motor 14 is
`shifted to an operating point 51' with a higher engine output
`Pmot, while maintaining momentary engine speed nmot1. If
`momentary operating point 51' corresponds to power require
`ment threshold value 55, engine control unit 44 in coopera
`tion with control and regulating unit 45 described above
`initiates a shift of operating point 51, 51' to an operating point
`51" located in engine speed range inmot2. A new power
`requirement threshold value 55' is then generated in engine
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`speed range inmot2. In this manner, drive motor 14 may
`always be operated in a partial load range 50 in which low fuel
`consumption is ensured.
`0040. To prevent the drive engine from stalling due to the
`use of a power reserve, even when brief peak loads occur,
`power requirement threshold values 55 are below regulating
`characteristic 54, and are preferably 20% lower than engine
`output Pmot, which defines regulating characteristic 54.
`Depending on required engine output Pmot determined via
`power requirement signals Z, control and regulating unit 45
`described above in cooperation with engine control unit
`44 initiates an automatic shift of the drive engine into the
`lowest possible engine speed range. Output speed nab of the
`output shaft of inventive gearbox stage 24 is then kept nearly
`constant, in the manner described above.
`0041. In order to ensure a high level of efficiency of
`mechanical-mechanical power-split transmission 25 and,
`therefore, a low fuel consumption of drive engine 14 within a
`large range of engine speed nmot, the engine power compo
`nent transmitted by continuously variable transmission 43
`decreases as engine speed nmot increases.
`0042. It will be understood that each of the elements
`described above, or two or more together, may also find a
`useful application in other types of constructions and meth
`ods differing from the types described above.
`0043. While the invention has been illustrated and
`described as embodied in an engine control system of a self
`propelled working machine, it is not intended to be limited to
`the details shown, since various modifications and structural
`changes may be made without departing in any way from the
`spirit of the present invention.
`0044) Without further analysis, the foregoing will so fully
`reveal the gist of the present invention that others can, by
`applying current knowledge, readily adapt it for various
`applications without omitting features that, from the stand
`point of prior art, fairly constitute essential characteristics of
`the generic or specific aspects of this invention.
`What is claimed as new and desired to be protected by
`Letters Patent is set forth in the appended claims:
`1. An engine control system of a self-propelled working
`machine with at least one drive engine having a regulatable
`rotational speed and working units driven with adjustable
`rotational speeds, comprising means for regulating the engine
`speed as a function of a load of the drive engine; a drive train
`coupling the at least one drive engine with one or more
`working units and including at least one gearbox stage that
`holds a drive speed of the working units constant, wherein the
`at least one gearbox stage is configured as a mechanical
`mechanical power-split transmission.
`2. The engine control system of a self-propelled working
`machine as defined in claim 1, wherein said gearbox stage has
`an input shaft coupled with an output shaft of the at least one
`drive engine, and an output shaft coupled with the drive train
`of at least one of the working units, so that a change in the
`engine speed results in a change in a rotational speed of the
`output shaft of the gearbox stage, and the rotational speed of
`the output shaft of the gearbox stage is adjusted within a
`rotational speed range in a stepless manner.
`3. The engine control system of a self-propelled working
`machine as defined in claim 1, wherein said mechanical
`mechanical power-split transmission includes a pulling
`means gearbox for transferring, at a constant rotational speed,
`a component of a drive power, and a continuously variable
`transmission for transferring at variable rotational speeds a
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`US 2009/01 18912 A1
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`May 7, 2009
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`further component of the drive power, with the power com
`ponents being combined in a Summing transmission of the
`mechanical-mechanical power-split transmission.
`4. The engine control system of a self-propelled working
`machine as defined in claim 3, wherein said pulling-means
`gearbox is designed as a belt drive, said continuously variable
`transmission is configured as a variation drive, and said Sum
`ming transmission is configured as a planetary gear set.
`5. The engine control device of a self-propelled working
`machine as defined in claim 4, wherein said pulling-means
`gearbox has a pulley assigned to an output shaft of the gear
`box stage and non-rotatably connected with an internal gear
`of a planetary gear set, said variator drive