WO2019158988A1 - Work vehicle comprising a traction hybrid power unit and control method therefor - Google Patents

Work vehicle comprising a traction hybrid power unit and control method therefor Download PDF

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Publication number
WO2019158988A1
WO2019158988A1 PCT/IB2018/060174 IB2018060174W WO2019158988A1 WO 2019158988 A1 WO2019158988 A1 WO 2019158988A1 IB 2018060174 W IB2018060174 W IB 2018060174W WO 2019158988 A1 WO2019158988 A1 WO 2019158988A1
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WO
WIPO (PCT)
Prior art keywords
electric machine
internal combustion
combustion engine
torque
work vehicle
Prior art date
Application number
PCT/IB2018/060174
Other languages
French (fr)
Inventor
Aurelio Soma'
Original Assignee
Ecothea S.R.L.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ecothea S.R.L. filed Critical Ecothea S.R.L.
Publication of WO2019158988A1 publication Critical patent/WO2019158988A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/42—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by the architecture of the hybrid electric vehicle
    • B60K6/48—Parallel type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/22—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs
    • B60K6/36—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the transmission gearings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/22—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs
    • B60K6/36—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the transmission gearings
    • B60K6/365—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the transmission gearings with the gears having orbital motion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/22—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs
    • B60K6/38—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the driveline clutches
    • B60K6/387—Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/22—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs
    • B60K6/40—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the assembly or relative disposition of components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/42—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by the architecture of the hybrid electric vehicle
    • B60K6/44—Series-parallel type
    • B60K6/442—Series-parallel switching type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/42—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by the architecture of the hybrid electric vehicle
    • B60K6/44—Series-parallel type
    • B60K6/445—Differential gearing distribution type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/42—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by the architecture of the hybrid electric vehicle
    • B60K6/48—Parallel type
    • B60K2006/4816—Electric machine connected or connectable to gearbox internal shaft
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/20—Off-Road Vehicles
    • B60Y2200/22—Agricultural vehicles
    • B60Y2200/221—Tractors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/90—Vehicles comprising electric prime movers
    • B60Y2200/92—Hybrid vehicles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/62—Hybrid vehicles

Definitions

  • the present invention relates to a hybrid work vehicle having a reduction gearbox or creep speed shift and an electric machine, in particular either a construction equipment vehicle, or an agricultural vehicle or a mixed use vehicle such as a tractor or a vehicle having a lifting boom or front loader.
  • the power train configuration of a hybrid electric vehicle can be divided into three types: series, parallel, and a combination of the two.
  • Series hybrid electric vehicles involve an internal combustion engine (ICE), generator, battery packs, capacitors and electric motors.
  • ICE internal combustion engine
  • ICE generator
  • battery packs battery packs
  • capacitors capacitors
  • electric motors electric motors
  • SHEV has no mechanical connections between the ICE and the wheels.
  • the series hybrid configuration is mostly used in heavy vehicles, military vehicles, and buses.
  • US- Al-2013/ 0157808 describes a series hybrid work vehicle comprising a planetary gear, a first electric machine connected to a sun gear of the planetary gear and a second electric machine connected to a ring gear of the planetary gear.
  • the drive provides a wider operational speed range and, substantially, is a two- engine unit attached to different gears of a CVT to provide an improved speed change device that can be used in a full electric mode of the work vehicle.
  • Such document does not show how possible accessories, e.g. of a work vehicle, are driven.
  • EP-A1-1199204 discloses a parallel hybrid traction system of a tractor comprising a planetary gear to split and re-combine the power from an internal combustion engine and a first and second electric machine.
  • the tractor does not have a full electric work and traction mode.
  • EP-A2-1317050 discloses a parallel hybrid traction system of a tractor with particular attention to the overall volume of power train installation and comprising a planetary gear to re-combine the power from an internal combustion engine and an electric machine.
  • the tractor presents a full electric work switched by a hydraulic actuator and traction mode but, when the power train is off, no hydraulic power is available to start directly in fully electric mode, so a manual actuation is provided in order to switch to the full electric mode.
  • W02011138308 discloses several embodiments of a series hybrid vehicle.
  • an internal combustion engine, an electric motor and a differential are connected to a planetary gear in a non-series embodiment.
  • the document is specifically focused on driving a power take-off, to which both the internal combustion engine and the planetary gear are coupled, and there is no specific indication about how traction is provided via the planetary gear.
  • the embodiment of figure 11 does not implement an important use of the vehicle, i.e. full electric functioning.
  • WO2011128772 discloses a series traction hybrid solution for telescopic vehicle including a parallel split for the working branch and a considering an embodiment with full-electric mode.
  • the telescopic vehicle does not include a CVT equipment but the electric drive motor is directly connected to a traditional mechanical driveline.
  • Each of the above work vehicles optimizes a single aspect.
  • a need is felt for an 'all round' work vehicle having a small-medium size and offering a full electric mode to e.g. travel and work inside a building such as a stall for cattle, providing a traditional internal combustion engine work and traction functioning at least in case of failure of one of the electric main components or while waiting for the maintenance thereof, and offering a wide speed range in order to work also in an open field at a certain speed.
  • a traditional work vehicle comprises a complex gearbox providing from three to more than 30 gearshifts, including travelling reduction or creep speed gears as well as a reduction gear for a power take-off.
  • gearbox tends to be complex not suitable for automatic control and not devoted to reduce consumption but reduces the efficiency of the work vehicle.
  • the scope of the present invention is to provide a work vehicle that satisfies the above mentioned needs.
  • the scope of the present invention is achieved by a work vehicle according to claim 1.
  • the hollow structure of the rotor provides an in-line layout of the electric motor and the internal combustion engine so that the hybrid power unit fits in a front engine compartment of an already designed or standard layout tractor, i.e. respective rotation axis of the hollow rotor and of a crankshaft of the internal combustion engine are substantially parallel to a longitudinal axis of the tractor.
  • the reduction gearbox may be either a multi-shift gearbox or a fixed gear ratio gearbox.
  • a reduction gear which may be either a creep speed shift of a discrete multi-shift gearbox or a constant reduction gear ratio gearbox, is located upstream of the differential and downstream of the power unit and a clutch so as to provide a suitable torque multiplication to provide creep speed and/or start, in particular uphill start of the tractor.
  • a planetary gear having a sun gear connected in torque transfer a the driveshaft of the internal combustion engine, a crown connected in torque transfer to the hollow rotor so that, when the locking mechanism is closed, the sun gear and the crown have the same angular speed, and a carrier connected in torque transfer to the clutch.
  • Such planetary gear splits torque from the power unit to the differential and accessories such as a hydraulic pump and a power take-off.
  • the internal combustion engine drives the electric machine via the crown of the planetary gear to provide electric power stored in a battery pack.
  • the internal combustion engine drives the hydraulic pump and/ or the power take-off via the hollow rotor and the differential via the driveshaft and the clutch when the electric machine is off.
  • a further electric machine is connected in torque transfer between the differential and the clutch.
  • a higher traction torque mode is provided because of the combination of torques by the electric machine and the internal combustion engine; when the clutch is open, the further electric machine provides traction power and the power unit generates electric power, i.e. a series hybrid vehicle is provided.
  • a reduction gear may be provided between the further electric machine and the differential in order to multiply torque when the clutch is open and working in electric series for traction.
  • batteries surround the electric machine, which has a lower height and a lower width than those of the internal combustion engine.
  • Fig. 1 is a functional sketch of a power unit according to the present invention providing a parallel hybrid layout
  • FIG. 2 is a torque diagram over vehicle speed of a vehicle comprising a power unit according to figure 1;
  • Fig. 3 is a sketch of a tractor comprising a power unit according to the invention.
  • Fig. 4 is a functional sketch of a second embodiment of the present invention providing a series/parallel hybrid layout
  • Fig. 5 is a functional sketch of a third embodiment of the present invention providing a further parallel layout.
  • Figure 1 shows as a whole a hybrid drive of a work vehicle comprising an electric machine 1 and an internal combustion engine 2 connected in parallel with respect to a gearbox 3 having a set of discrete shifts, e.g. a creep speed gear, a direct drive gear with internal combustion engine 2 and a high speed gear.
  • electric machine 1 has a hollow rotor and houses a drive shaft S connected to internal combustion engine 2.
  • the hybrid drive further comprises a power take-off 4 connected to be either driven by electric machine 1 or internal combustion engine 2 or both in order to power implements to be attached to the work vehicle, such as hydraulic cylinders.
  • Torque from electric machine 1 and internal combustion engine 2 is transferred to gearbox 3 and power take-off 4 via a transmission comprising a decoupler 5 to disconnect internal combustion engine 2 from electric machine 1, gearbox 3 and power take-off 4 to provide a full electric mode of the work vehicle.
  • the transmission comprises a locking mechanism 6 to selectively lock shaft S to the hollow rotor of electric machine 1.
  • power take-off 4 is driven by internal combustion engine 2 when locking mechanism 6 is closed via the hollow rotor of electric machine 1.
  • the transmission comprises a clutch 7 to rotationally disconnect power take-off 4 from any power source if needed, so that power take-off may be stopped when one of electric machine 1 and internal combustion engine 2 are rotating.
  • the transmission further comprises a planetary gear to split the power of electric machine 1 and internal combustion engine 2 between gearbox 3 and power take-off 4.
  • a sun gear 8 is attached to drive shaft S
  • a crown gear 9 is connected to electric motor 1 at a fixed gear ratio and a carrier 10 drives gearbox 3, i.e. a discrete shift gearbox.
  • crown gear 9 is connected to a gear 11 of the hollow rotor via paired idle gears 12.
  • the planetary gear faces electric machine 1 and paired idle gears 12 are offset from axes of electric machine 1 and sun gear 8. According to a preferred embodiment, such axes are substantially coincident as shown in figure 1.
  • power take-off 4 is driven via gear 11 and a hydraulic pump 13 is connected in parallel to the power take-off 4 with respect to gear 11.
  • power take-off 4 and hydraulic pump 13 are driven by the same shaft connected to gear 11.
  • Decoupler 5 is either an electronically actuated friction clutch or a freewheel.
  • An inverter 14 and a battery pack 15 are provided to control and power electric machine 1.
  • discrete shift gearbox 3 drives a differential 16 and is selectively rotationally disengageable from carrier 10 via a clutch 17.
  • the latter is open when the shift of gearbox 3 changes, as generally happens in a manual shift via a clutch pedal or in a robotized shift gearbox, wherein the clutch and the shift are operated via actuators, e.g. electric or fluid actuators.
  • Figure 2 is a diagram showing the traction torque generated by the combination of electric machine 1 and internal combustion engine 2 over the speed range of the work vehicle when no accessory, e.g. power take-off 4 is driven and the battery pack is fully charged, e.g. not under charge. Furthermore, figure 2 is obtained at a fixed shift of gearbox 3.
  • Inverter 14 preferably controls electric machine
  • electric machine 1 may work at peak conditions over its functioning range and in particular at start from braking or stop, in particular at uphill start.
  • Peak functioning of electric motor 1 is provided by the inverter that inputs a power electric current higher than the nominal electric current of electric machine 1.
  • the higher torque of peak functioning mode can be kept only for a short amount of time, e.g. a few minutes, but helps to overcome peak load such as when there is an obstacle on the ground, e.g. a large rock, a short uphill road, a small cliff or the like.
  • peak torque of electric machine 1 is higher than maximum torque of internal combustion engine 2.
  • peak torque of electric machine 1 is at least 1,5-2 times maximum torque of internal combustion engine 2.
  • Electric machine 1 is then either switched off, e.g. when the battery pack is fully charged, (lower line of figure 2) or functions as a generator to charge battery pack and, at the same time, drive gear 11 via locking mechanism 6.
  • locking mechanism 6 is closed so that, via paired gears 12, both sun gear 8 and crown gear 9 have the same angular speed.
  • Traction performance between points C and D' of figure 2 is provided when electric machine 1 functioning as a motor provides a further torque up to the peak torque.
  • Electric machine 1 may be either switched automatically on based on monitoring of functioning parameters such as velocity or controlled manually by the driver, e.g. via a button, lever or the like that the driver switches when sitting on a driver's seat.
  • velocity or angular speed of driveshaft S etc. can be monitored via sensors already provided in standard internal combustion engines and/or via standard controls implemented in inverters. Therefore there is no need of additional sensors, such as torque sensors, to control the power unit.
  • angular speed of internal combustion engine 2 is set by dimensional parameters, such as diameter of the wheels, and mechanical parameters, such as gear ration of planetary gear etc. and a reference angular speed of electric machine 1 is set slightly lower, for each vehicle speed set by the driver via the cruise control, to that of internal combustion engine 2, e.g. no more than 10% lower, preferably no more than 5% lower, to provide synchronous tie.
  • the inverter controls electric machine 1 to keep constant the reference angular speed set via cruise control regardless the load applied on e.g. the wheels or tracks of the work vehicle. Indeed, in case of a climb on a uphill, the load increase tends to slow down internal combustion engine 2 but is opposed by the action of electric machine 1 that, in order to keep its reference angular speed constant, increases torque as necessary until its peak value. The additional torque provided by electric machine 1 eventually produces an additional effect to that of a creep speed gear.
  • locking mechanism 6 is decoupled and clutch 7 open.
  • clutch 17 is automatically closed, motor 30 is switched off and accelerator pedal controls the torque of internal combustion engine 2. Electric machine 1 supplies additional torque, if needed, in synchronous tie.
  • An accelerator pedal operated by the driver sets a desired torque level and, when internal combustion engine 2 is on, such torque level shall be primarily provided by the internal combustion engine and the additional torque, if needed, is provided by electric machine 1 according to a master/ slave configuration.
  • the combination of electric motor 1 and internal combustion engine 2 has a total maximum power between 50 and 130 kW, preferably evenly split.
  • Electric machine 1 is driven by internal combustion engine 2. In such an instance, a portion of torque from internal combustion engine 2 is absorbed by electric machine 1 and depends on the electric load set by a control unit to charge the battery pack 15. This is performed when locking mechanism 6 angularly couples drive shaft S to the hollow rotor of electric machine 1. As an alternative, locking mechanism 6 is open and, via inverter 14, electric machine 1 provides a variable braking torque so as to balance torque of driveshaft S and, at the same time, give priority to execution of the traction command provided by the accelerator pedal.
  • a control unit is programmed so that, when receiving a command from the user via e.g. a selector, a button or the like in the cockpit of the work vehicle, preferably on a dashboard thereof, internal combustion engine 2 is switched off and any activity alone or in combination of the work vehicle is provided via electric machine 1, including in particular traction and activation of power take-off 4.
  • Locking mechanism 6 angularly attaches drive shaft S and the hollow rotor of electric machine 1.
  • Decoupler 5 angularly detaches internal combustion engine 2 from driveshaft S.
  • the accelerator pedal controls a torque output of electric machine 1 and the desired speed is obtained by the user acting on gearbox 3 in the same manner as if the prime mover were internal combustion engine 2.
  • power take-off 4 can be powered also when locking mechanism 6 disengages drive shaft S and gear 11.
  • Activation of hydraulic pump 13 when vehicle is stopped is obtained by opening decouplers or clutches 5 and 17 and switch electric motor 1 on or by closing decoupler 5, keep clutch 17 open and switch internal combustion engine 2 on.
  • torque at start from braking or stop is provided by internal combustion engine 2.
  • Connection of internal combustion engine 2 to the wheels of tracks of the working vehicle is operated by the user in a traditional manner, e.g. via clutch 17 controlled by the clutch pedal or by a driver' s interface, i.e. a manual selector, of the robotized shift gearbox.
  • tractor T starts from stopped or braked vehicle via internal combustion engine 2 only and a proper closure timing of clutch 17.
  • control unit is programmed to provide a warning signal to the driver when charge level of the battery pack 15 falls below a predefined threshold.
  • Warning signal to the driver may be an audio or a visual warning or a combination of both. This is important in particular if electric machine 1 is providing a torque contribution when the work vehicle is travelling on a steep uphill road in order to avoid that the driver is caught off- guard and has time to decide how to drive the work vehicle when electric machine 1 is temporarily unavailable.
  • control unit is programmed so that, when charge level of the battery pack falls below a predefined safety threshold, power provided by electric machine 1 decreases according to a predefined path until internal combustion engine 2 is the only power source. For example, output power of electric machine 1 linearly decreases as a function of the charge level below the safety threshold.
  • FIG 3 shows a schematic view of a tractor T, in particular a light tractor having a maximum installed power as example of 50-130 kW, equipped with the hybrid driveline of figure 1.
  • tractor T comprises a framed chassis C supported by wheels W or tracks, and provided to support electric motor 1, internal combustion engine 2 and battery pack 15.
  • Tractor T also comprises a vibration isolated platform P where a seat of a driver (not shown) is mounted.
  • platform P is connected to the framed chassis C by means of silent block or suspension in order to cut-off functioning vibrations, such as vibrations from internal combustion engine 2 and vibration induced by terramechanics interaction, and increase comfort of the driver.
  • framed chassis C comprises a first and a second longitudinal main beams 21, 22 longitudinally elongated between front wheels and rear wheels W and laterally distanced to provide a seat and a location for electric motor 1 and internal combustion engine 2.
  • battery pack 15 is mounted on main beams 21, 22 between internal combustion engine 2 and platform P and surrounds, in particular upwardly and laterally surrounds, electric motor 1.
  • battery pack 15 has a different vibration decoupling, if any, with respect to that of platform P.
  • battery pack 15 is mounted preferably by means of silent blocks on main beams 21, 22.
  • Electric motor 1 and/or battery pack 15 longitudinally face internal combustion engine 2 in order to fit in the usual location of a power unit in a tractor, i.e. in front of platform P carried by main beams 21, 22.
  • Gearbox 3 is located below platform P and longitudinally faces differential 16, i.e. a normal layout in tractors.
  • Figure 4 shows a further embodiment of the present invention wherein the same numerals already used in the above paragraphs indicate functionally identical elements to those described for embodiment of figure 1.
  • the embodiment in figure 4 differs from that in figure 1 as follows.
  • figure 4 shows a hybrid drivetrain for tractor T having an additional electric motor 30 connected to differential 16 for traction of wheels or tracks W.
  • Electric motor 30 is controlled via an inverter 31 and powered by battery pack 15.
  • electric motor 1 has a through shaft connected via clutch 17 to drive shaft S of internal combustion engine 2.
  • driveshaft S is connected in torque transfer to the through shaft of electric motor 30 via a reduction gearbox 32 such that the angular speed of electric motor 30 is lower than that of driveshaft S.
  • the speed ratio of reduction gearbox 32 is constant and the gearbox is downstream of clutch 17.
  • reduction gearbox 32 may be upstream of clutch 17.
  • electric motor 30 is offset from differential 16 and/ or clutch 17 and is connected in torque transfer for traction via a dedicated reduction gearbox. It is also possible that power unit 1, 2 and electric motor 30 are connected to differential 16 via a reduction gear located downstream of clutch 17. In all embodiments, reduction gearbox has fixed gear ratios / discrete shifts that are selected by the driver and are not automatically selected on the basis of vehicle functioning parameters.
  • differential 16 receives torque from electric motor 1, internal combustion engine 2 and electric motor 30 or at least just one of the latter power units, depending on the status of decoupler 5, locking mechanism 6 and clutch 17.
  • tractor T provides at least a higher traction torque functioning mode and a lower traction torque functioning mode.
  • a maximum vehicle speed of the former is lower than a maximum vehicle speed of the latter.
  • the higher traction torque functioning mode is provided when clutch 17 is closed and electric machine 1 and/ or internal combustion engine 2, via reduction gearbox 32, provide a torque contribution for differential 16.
  • the combined maximum torque of electric machine 1 and internal combustion engine 2 is higher than maximum torque of electric motor 30.
  • the highest torque provided to differential 16 comes from electric machine 1 in peak functioning condition in order to e.g. provide uphill start at a creep speed.
  • a predefined tractor speed threshold e.g. 5 km/h
  • internal combustion engine 2 automatically switches on and decoupler 5 provides the relative torque to driveshaft S.
  • the accelerator pedal operated by the driver controls torque of the internal combustion engine and electric machine 1 provides additional torque, if needed, e.g. according to the embodiments already discussed in relation to figure 1.
  • both electric machine 1 and internal combustion engine 2 provide driving torque, further electric machine 30 is generally off. The latter is automatically switched on in order to provide further torque, e.g. based on monitoring of functioning parameters such as tractor speed or angular speed of any driveline rotating element. Traction torque provided by electric machine 1 and internal combustion engine 2 is multiplied by reduction gear 32.
  • the lower traction torque functioning mode is provided when clutch 17 is open and further electric machine 30 provides traction torque.
  • electric machine 30 is connected in direct drive to differential 16 and starting from stopped or braked vehicle is provided via electric machine 1 by closing clutch 17. At a predefined speed threshold, clutch 17 automatically opens and electric machine 30 provides traction torque.
  • a further reduction gear is provided to couple in torque transfer electric machine 30 to differential 16.
  • the relative torque multiplication provides a sufficient torque level to differential 16 at start from braked or stopped vehicle when clutch 17 is open.
  • the accelerator pedal controls the torque level, i.e. the absorbed electric current, provided by further electric machine 30 when clutch 17 is open.
  • the switch between the two functioning modes may be manual, e.g. via a selector operable by the driver during travel of the tractor, or automatically as discussed for the embodiment where torque at start from braked or stopped vehicle is always provided by electric motor 1.
  • the driver may change the angular speed of the power take-off and/or of hydraulic pump 13, both driven by electric machine 1 and/ or internal combustion engine 2.
  • electric motor 30 When provided on a tractor, i.e. a tractor having the framed chassis and platform shown in figure 3, electric motor 30 is located below platform P, in particular longitudinally facing rear differential 16.
  • driveshaft S is vertically spaced from an input shaft of differential 16 and/ or from a hub of wheels W.
  • a suitable not-shown transmission e.g. gears or a chain transmission, is therefore provided to transfer torque between driveshaft S and electric motor 30 and/ or differential 16.
  • Such transmission may incorporate the speed reducing function of gearbox 32.
  • Figure 5 discloses a further embodiment of the present invention, where numerals already used for describing the preceding embodiments indicate the same functional elements of the preceding paragraphs.
  • the layout in figure 5 differs from that in figure 1 as follows.
  • Crown 9 is connected to an electric machine 30' with a reduction gear ratio when the machine drives the crown.
  • Electric machine 30' is functionally similar to electric machine 30 but is associated to planetary gear 8, 9, 10 and not downstream of the latter, as the case in the layout of figure 4.
  • electric machine 30' is controlled and powered by an inverter and a battery pack, for example by battery pack 15.
  • Gear 11 is coupled to drive power take-off 4 and/ or hydraulic pump 13.
  • carrier 9 is always connected to gearbox 3, i.e. there is no clutch to selectively couple in rotation carrier 9 and gearbox 3.
  • planetary gear 8, 9, 10 combine torques from internal combustion engine 2 and electric machine 30'.
  • internal combustion engine 2 is kept at some constant angular speed functioning points having a relatively high efficiency. In case a higher torque input is associated to the angular position of the accelerator pedal electric machine 30' provides the missing torque.
  • gearbox 3 may have a structure with two shifts, e.g. a creep speed shift and a direct drive shift. Such simple structure is also due to the fact that reverse speed is provided by inversion of electric machine 30'.
  • locking mechanism 6 may be open so that power take-off and/ or hydraulic pump 13 are driven at an angular speed that is independent from that of driveshaft S.
  • electric machine 1 may function as a generator to recharge battery pack 15.
  • Decoupler 5, locking mechanism 6 and clutch 17 may differ or be the same kind of component and are preferably capable of engaging and disengaging the relative power unit during rotation and torque transmission of the relative connecting shaft.
  • Electric motor 30 may be an electric machine functioning also as a generator to charge battery pack 15 during braking of tractor T.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
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Abstract

A work vehicle (T) comprises a traction hybrid power unit (1, 2), a hydraulic pump (13) driven by the hybrid power unit (1, 2) for powering an implement of the tractor and a power take-off (4) powered by the hybrid power unit (1, 2), wherein an electric machine (1) of the hybrid power unit has a hollow rotor housing a drive shaft (S) driven by the internal combustion engine (2) and connected in torque transfer to a differential (16) of the vehicle; an angular decoupler (5) selectively connects in rotation the drive shaft (S) to the internal combustion engine (2) and a locking mechanism (6) selectively connects in rotation the drive shaft (S) and the hollow rotor.

Description

WORK VEHICLE COMPRISING A TRACTION HYBRID POWER
UNIT AND CONTROL METHOD THEREFOR
DESCRIPTION
TECHNICAL FIELD
The present invention relates to a hybrid work vehicle having a reduction gearbox or creep speed shift and an electric machine, in particular either a construction equipment vehicle, or an agricultural vehicle or a mixed use vehicle such as a tractor or a vehicle having a lifting boom or front loader.
STATE OF THE ART
There is no standard solution for the optimal size ratio of the internal combustion engine and the electric system, and the best choice includes complex trade-offs between the power as well as between cost and performance. The power train configuration of a hybrid electric vehicle (HEV) can be divided into three types: series, parallel, and a combination of the two. Series hybrid electric vehicles (SHEV) involve an internal combustion engine (ICE), generator, battery packs, capacitors and electric motors. SHEV has no mechanical connections between the ICE and the wheels. The series hybrid configuration is mostly used in heavy vehicles, military vehicles, and buses.
In a PHEV, mechanical and electrical powers are both connected to the driveline. In the case of parallel architectures, good performance during acceleration is possible because of the combined power from both engines. Different control strategies are used and in a preferred approach. Moreover mechanical and electric power could be decouples the system has a high operating flexibility enabling three modes of operation: purely combustion; purely electric and hybrid.
In the series-parallel hybrid configuration can be highlighted two main power paths. In mechanical power path, the energy generated by the combustion engine is directly transmitted to the wheels while the electric path the energy generated by the thermal engine is converted first into electrical energy by means of the generator and then again converted to mechanical energy delivered at the wheels. It is possible therefore to have mixed architectures denominated "power splits" in which the installed power is divided by means of mechanical couplers. Combination of parallel and series hybrid configurations are further divided into sub-categories based on how the power is distributed.
For example, W02011101726 relates to a parallel hybrid work vehicle comprising an internal combustion engine, a planetary gear having a sun gear connected to the internal combustion engine via a synchronizer, a traction electric machine connected in torque transfer to a ring gear of the planetary gear and an accessory electric machine to charge a battery when driven by the internal combustion engine or to drive a hydraulic pump for one or more hydraulic work device of the vehicle in a full electric mode. In particular, in such a full electric mode, the sun gear is braked and traction power is provided by the first electric machine via the ring gear. When the battery is low, the internal combustion engine is controlled to be switched on and connected to the sun gear via the synchronizer and a clutch.
US- Al-2013/ 0157808 describes a series hybrid work vehicle comprising a planetary gear, a first electric machine connected to a sun gear of the planetary gear and a second electric machine connected to a ring gear of the planetary gear. In particular, having the sun gear permanently connected to an electric machine, the drive provides a wider operational speed range and, substantially, is a two- engine unit attached to different gears of a CVT to provide an improved speed change device that can be used in a full electric mode of the work vehicle. Such document does not show how possible accessories, e.g. of a work vehicle, are driven.
EP-A1-1199204 discloses a parallel hybrid traction system of a tractor comprising a planetary gear to split and re-combine the power from an internal combustion engine and a first and second electric machine. The tractor does not have a full electric work and traction mode.
EP-A2-1317050 discloses a parallel hybrid traction system of a tractor with particular attention to the overall volume of power train installation and comprising a planetary gear to re-combine the power from an internal combustion engine and an electric machine. The tractor presents a full electric work switched by a hydraulic actuator and traction mode but, when the power train is off, no hydraulic power is available to start directly in fully electric mode, so a manual actuation is provided in order to switch to the full electric mode.
W02011138308 discloses several embodiments of a series hybrid vehicle. However, in the embodiment of figure 11, an internal combustion engine, an electric motor and a differential are connected to a planetary gear in a non-series embodiment. The document is specifically focused on driving a power take-off, to which both the internal combustion engine and the planetary gear are coupled, and there is no specific indication about how traction is provided via the planetary gear. Furthermore, the embodiment of figure 11 does not implement an important use of the vehicle, i.e. full electric functioning.
WO2011128772 discloses a series traction hybrid solution for telescopic vehicle including a parallel split for the working branch and a considering an embodiment with full-electric mode. The telescopic vehicle does not include a CVT equipment but the electric drive motor is directly connected to a traditional mechanical driveline.
Each of the above work vehicles optimizes a single aspect. However, a need is felt for an 'all round' work vehicle having a small-medium size and offering a full electric mode to e.g. travel and work inside a building such as a stall for cattle, providing a traditional internal combustion engine work and traction functioning at least in case of failure of one of the electric main components or while waiting for the maintenance thereof, and offering a wide speed range in order to work also in an open field at a certain speed.
Furthermore, a traditional work vehicle comprises a complex gearbox providing from three to more than 30 gearshifts, including travelling reduction or creep speed gears as well as a reduction gear for a power take-off. Such gearbox tends to be complex not suitable for automatic control and not devoted to reduce consumption but reduces the efficiency of the work vehicle.
There is therefore the need to provide a compact layout that in particular may be suitable for being introduced in the engine compartment and/ or a framed chassis of an already designed vehicle to substitute an internal combustion engine.
SCOPE AND DISCLOSURE OF THE INVENTION
The scope of the present invention is to provide a work vehicle that satisfies the above mentioned needs.
The scope of the present invention is achieved by a work vehicle according to claim 1. The hollow structure of the rotor provides an in-line layout of the electric motor and the internal combustion engine so that the hybrid power unit fits in a front engine compartment of an already designed or standard layout tractor, i.e. respective rotation axis of the hollow rotor and of a crankshaft of the internal combustion engine are substantially parallel to a longitudinal axis of the tractor.
Furthermore, the reduction gearbox may be either a multi-shift gearbox or a fixed gear ratio gearbox.
Preferably, a reduction gear, which may be either a creep speed shift of a discrete multi-shift gearbox or a constant reduction gear ratio gearbox, is located upstream of the differential and downstream of the power unit and a clutch so as to provide a suitable torque multiplication to provide creep speed and/or start, in particular uphill start of the tractor.
Preferably, it is provided a planetary gear having a sun gear connected in torque transfer a the driveshaft of the internal combustion engine, a crown connected in torque transfer to the hollow rotor so that, when the locking mechanism is closed, the sun gear and the crown have the same angular speed, and a carrier connected in torque transfer to the clutch. Such planetary gear splits torque from the power unit to the differential and accessories such as a hydraulic pump and a power take-off.
Preferably, via the layout provided in figure 1, the internal combustion engine drives the electric machine via the crown of the planetary gear to provide electric power stored in a battery pack. Preferably, via the layout provided in figure 1, the internal combustion engine drives the hydraulic pump and/ or the power take-off via the hollow rotor and the differential via the driveshaft and the clutch when the electric machine is off.
Preferably, according to the embodiment of figure 4, a further electric machine is connected in torque transfer between the differential and the clutch. When the clutch is closed, a higher traction torque mode is provided because of the combination of torques by the electric machine and the internal combustion engine; when the clutch is open, the further electric machine provides traction power and the power unit generates electric power, i.e. a series hybrid vehicle is provided. A reduction gear may be provided between the further electric machine and the differential in order to multiply torque when the clutch is open and working in electric series for traction.
Preferably, in the in-line layout of the electric machine and internal combustion engine, batteries surround the electric machine, which has a lower height and a lower width than those of the internal combustion engine.
Other advantages of the present invention are discussed in the description and cited in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in the following based on non limiting examples shown for explanation purposes in the attached drawings, which respectively refer to:
Fig. 1 is a functional sketch of a power unit according to the present invention providing a parallel hybrid layout;
- Fig. 2 is a torque diagram over vehicle speed of a vehicle comprising a power unit according to figure 1;
Fig. 3 is a sketch of a tractor comprising a power unit according to the invention;
Fig. 4 is a functional sketch of a second embodiment of the present invention providing a series/parallel hybrid layout; and
Fig. 5 is a functional sketch of a third embodiment of the present invention providing a further parallel layout.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 shows as a whole a hybrid drive of a work vehicle comprising an electric machine 1 and an internal combustion engine 2 connected in parallel with respect to a gearbox 3 having a set of discrete shifts, e.g. a creep speed gear, a direct drive gear with internal combustion engine 2 and a high speed gear. In particular electric machine 1 has a hollow rotor and houses a drive shaft S connected to internal combustion engine 2.
The hybrid drive further comprises a power take-off 4 connected to be either driven by electric machine 1 or internal combustion engine 2 or both in order to power implements to be attached to the work vehicle, such as hydraulic cylinders.
Torque from electric machine 1 and internal combustion engine 2 is transferred to gearbox 3 and power take-off 4 via a transmission comprising a decoupler 5 to disconnect internal combustion engine 2 from electric machine 1, gearbox 3 and power take-off 4 to provide a full electric mode of the work vehicle. Furthermore, the transmission comprises a locking mechanism 6 to selectively lock shaft S to the hollow rotor of electric machine 1. According to the embodiment of figure 1, power take-off 4 is driven by internal combustion engine 2 when locking mechanism 6 is closed via the hollow rotor of electric machine 1. Furthermore, the transmission comprises a clutch 7 to rotationally disconnect power take-off 4 from any power source if needed, so that power take-off may be stopped when one of electric machine 1 and internal combustion engine 2 are rotating.
The transmission further comprises a planetary gear to split the power of electric machine 1 and internal combustion engine 2 between gearbox 3 and power take-off 4. In particular, a sun gear 8 is attached to drive shaft S, a crown gear 9 is connected to electric motor 1 at a fixed gear ratio and a carrier 10 drives gearbox 3, i.e. a discrete shift gearbox. In particular, crown gear 9 is connected to a gear 11 of the hollow rotor via paired idle gears 12. In particular, the planetary gear faces electric machine 1 and paired idle gears 12 are offset from axes of electric machine 1 and sun gear 8. According to a preferred embodiment, such axes are substantially coincident as shown in figure 1.
According to the preferred embodiment of figure 1, power take-off 4 is driven via gear 11 and a hydraulic pump 13 is connected in parallel to the power take-off 4 with respect to gear 11. Preferably, power take-off 4 and hydraulic pump 13 are driven by the same shaft connected to gear 11.
Decoupler 5 is either an electronically actuated friction clutch or a freewheel.
An inverter 14 and a battery pack 15 are provided to control and power electric machine 1.
Furthermore, discrete shift gearbox 3 drives a differential 16 and is selectively rotationally disengageable from carrier 10 via a clutch 17. In particular, the latter is open when the shift of gearbox 3 changes, as generally happens in a manual shift via a clutch pedal or in a robotized shift gearbox, wherein the clutch and the shift are operated via actuators, e.g. electric or fluid actuators.
PARALLEL LAYOUT - FUNCTIONING AT TRACTION
Figure 2 is a diagram showing the traction torque generated by the combination of electric machine 1 and internal combustion engine 2 over the speed range of the work vehicle when no accessory, e.g. power take-off 4 is driven and the battery pack is fully charged, e.g. not under charge. Furthermore, figure 2 is obtained at a fixed shift of gearbox 3.
At start from braking or stop, torque is provided by electric machine 1 functioning as an electric motor. Inverter 14 preferably controls electric machine
1 so that torque is independent from vehicle speed until a predefined vehicle speed, e.g. lower than 5 km/h. This is obtained when internal combustion engine
2 is switched off, decoupler 5 angularly disconnects internal combustion engine 2 from driving shaft S and locking mechanism 6 angularly connects drive shaft S to gear 11 and the hollow rotor of electric machine 1. Furthermore, clutch 17 is closed as well. Clutch 7 is open and power take-off 4 is not powered. When drive shaft S and gear 11 are rigidly connected via locking mechanism 6, sun gear 8 provides a reaction torque to that of crown gear 9 so as to make carrier 10 rotate to provide an input torque to gearbox 3. Preferably, when drive shaft S and gear 11 are locked, gearbox 3 is connected in direct drive, i.e. crown gear 9 and gear 11 have the same number of teeth and paired gears 12 are equal. It is however possible that non-unitary gear ratio is realized between drive shaft S and the carrier when locking mechanism 6 is locked.
It is important to note that electric machine 1 may work at peak conditions over its functioning range and in particular at start from braking or stop, in particular at uphill start. Peak functioning of electric motor 1 is provided by the inverter that inputs a power electric current higher than the nominal electric current of electric machine 1. The higher torque of peak functioning mode can be kept only for a short amount of time, e.g. a few minutes, but helps to overcome peak load such as when there is an obstacle on the ground, e.g. a large rock, a short uphill road, a small cliff or the like.
As shown by figure 2, peak torque of electric machine 1 is higher than maximum torque of internal combustion engine 2. Preferably, peak torque of electric machine 1, is at least 1,5-2 times maximum torque of internal combustion engine 2.
At a higher speed, e.g. above a predefined vehicle speed limit, preferably in the range 5-10 km/h, internal combustion engine 2 is automatically switched on. Electric machine 1 is then either switched off, e.g. when the battery pack is fully charged, (lower line of figure 2) or functions as a generator to charge battery pack and, at the same time, drive gear 11 via locking mechanism 6. When electric machine 1 is switched off, locking mechanism 6 is closed so that, via paired gears 12, both sun gear 8 and crown gear 9 have the same angular speed.
In case, the battery pack is already fully charged, torque output over vehicle speed is given in figure 2 between points C and D as a standard internal combustion engine work vehicle.
Traction performance between points C and D' of figure 2 is provided when electric machine 1 functioning as a motor provides a further torque up to the peak torque. Electric machine 1 may be either switched automatically on based on monitoring of functioning parameters such as velocity or controlled manually by the driver, e.g. via a button, lever or the like that the driver switches when sitting on a driver's seat. In particular, velocity or angular speed of driveshaft S etc. can be monitored via sensors already provided in standard internal combustion engines and/or via standard controls implemented in inverters. Therefore there is no need of additional sensors, such as torque sensors, to control the power unit.
As a non-limiting example of automatic controlling of electric machine 1, when the driver sets the vehicle speed via a cruise control, a suitable angular speed of both electric machine 1, when batteries are sufficiently charged, and internal combustion engine 2 is reached. In particular, angular speed of internal combustion engine 2 is set by dimensional parameters, such as diameter of the wheels, and mechanical parameters, such as gear ration of planetary gear etc. and a reference angular speed of electric machine 1 is set slightly lower, for each vehicle speed set by the driver via the cruise control, to that of internal combustion engine 2, e.g. no more than 10% lower, preferably no more than 5% lower, to provide synchronous tie. In such a condition, the inverter controls electric machine 1 to keep constant the reference angular speed set via cruise control regardless the load applied on e.g. the wheels or tracks of the work vehicle. Indeed, in case of a climb on a uphill, the load increase tends to slow down internal combustion engine 2 but is opposed by the action of electric machine 1 that, in order to keep its reference angular speed constant, increases torque as necessary until its peak value. The additional torque provided by electric machine 1 eventually produces an additional effect to that of a creep speed gear. The above is achieved when locking mechanism 6 is decoupled and clutch 7 open. When the intervention of electric machine is manually controlled by the driver, clutch 17 is automatically closed, motor 30 is switched off and accelerator pedal controls the torque of internal combustion engine 2. Electric machine 1 supplies additional torque, if needed, in synchronous tie.
An accelerator pedal operated by the driver sets a desired torque level and, when internal combustion engine 2 is on, such torque level shall be primarily provided by the internal combustion engine and the additional torque, if needed, is provided by electric machine 1 according to a master/ slave configuration.
Preferably, the combination of electric motor 1 and internal combustion engine 2 has a total maximum power between 50 and 130 kW, preferably evenly split.
Other functioning conditions of the work vehicle may be obtained according to a number of alternatives. The following provides a list of non- limiting preferred embodiments.
CHARGING
Electric machine 1 is driven by internal combustion engine 2. In such an instance, a portion of torque from internal combustion engine 2 is absorbed by electric machine 1 and depends on the electric load set by a control unit to charge the battery pack 15. This is performed when locking mechanism 6 angularly couples drive shaft S to the hollow rotor of electric machine 1. As an alternative, locking mechanism 6 is open and, via inverter 14, electric machine 1 provides a variable braking torque so as to balance torque of driveshaft S and, at the same time, give priority to execution of the traction command provided by the accelerator pedal.
When the battery pack 15 is fully charged and there is no need of torque contribution by electric machine 1, the latter may be switched off and locking mechanism 6 be in the engaged position for driving power take-off 4 and/or hydraulic pump 13.
FULL ELECTRIC
According to a preferred embodiment, a control unit is programmed so that, when receiving a command from the user via e.g. a selector, a button or the like in the cockpit of the work vehicle, preferably on a dashboard thereof, internal combustion engine 2 is switched off and any activity alone or in combination of the work vehicle is provided via electric machine 1, including in particular traction and activation of power take-off 4. Locking mechanism 6 angularly attaches drive shaft S and the hollow rotor of electric machine 1. Decoupler 5 angularly detaches internal combustion engine 2 from driveshaft S.
The accelerator pedal controls a torque output of electric machine 1 and the desired speed is obtained by the user acting on gearbox 3 in the same manner as if the prime mover were internal combustion engine 2.
In case of stopped vehicle, power take-off 4 can be powered also when locking mechanism 6 disengages drive shaft S and gear 11.
Activation of hydraulic pump 13 when vehicle is stopped is obtained by opening decouplers or clutches 5 and 17 and switch electric motor 1 on or by closing decoupler 5, keep clutch 17 open and switch internal combustion engine 2 on.
LOW BATTERY
According to a preferred embodiment, torque at start from braking or stop is provided by internal combustion engine 2. Connection of internal combustion engine 2 to the wheels of tracks of the working vehicle is operated by the user in a traditional manner, e.g. via clutch 17 controlled by the clutch pedal or by a driver' s interface, i.e. a manual selector, of the robotized shift gearbox.
In particular, in an emergency mode where e.g. there is a failure in a major power electric element, as an inverter, electric machine or the like, via the reduction gearbox or shift it is possible that tractor T starts from stopped or braked vehicle via internal combustion engine 2 only and a proper closure timing of clutch 17.
It is important to note that, in case a high level of torque is required to e.g. climb out of a steep cliff, and the charge of battery pack 15 is low, the driver may keep the work vehicle braked and let internal combustion engine 2 charge the battery pack via electric machine 1 functioning as a generator. When the battery pack is sufficiently charged, electric machine 1 is switched to function as a motor and provide its torque, if the case peak torque, to climb at a very low speed out of the steep cliff.
According to a preferred embodiment, the control unit is programmed to provide a warning signal to the driver when charge level of the battery pack 15 falls below a predefined threshold. Warning signal to the driver may be an audio or a visual warning or a combination of both. This is important in particular if electric machine 1 is providing a torque contribution when the work vehicle is travelling on a steep uphill road in order to avoid that the driver is caught off- guard and has time to decide how to drive the work vehicle when electric machine 1 is temporarily unavailable.
Preferably, the control unit is programmed so that, when charge level of the battery pack falls below a predefined safety threshold, power provided by electric machine 1 decreases according to a predefined path until internal combustion engine 2 is the only power source. For example, output power of electric machine 1 linearly decreases as a function of the charge level below the safety threshold.
Figure 3 shows a schematic view of a tractor T, in particular a light tractor having a maximum installed power as example of 50-130 kW, equipped with the hybrid driveline of figure 1. In particular, tractor T comprises a framed chassis C supported by wheels W or tracks, and provided to support electric motor 1, internal combustion engine 2 and battery pack 15. Tractor T also comprises a vibration isolated platform P where a seat of a driver (not shown) is mounted. Preferably, platform P is connected to the framed chassis C by means of silent block or suspension in order to cut-off functioning vibrations, such as vibrations from internal combustion engine 2 and vibration induced by terramechanics interaction, and increase comfort of the driver.
According to figure 3, framed chassis C comprises a first and a second longitudinal main beams 21, 22 longitudinally elongated between front wheels and rear wheels W and laterally distanced to provide a seat and a location for electric motor 1 and internal combustion engine 2. In particular, figure 3 shows that battery pack 15 is mounted on main beams 21, 22 between internal combustion engine 2 and platform P and surrounds, in particular upwardly and laterally surrounds, electric motor 1. Preferably, battery pack 15 has a different vibration decoupling, if any, with respect to that of platform P. In particular, battery pack 15 is mounted preferably by means of silent blocks on main beams 21, 22. Electric motor 1 and/or battery pack 15 longitudinally face internal combustion engine 2 in order to fit in the usual location of a power unit in a tractor, i.e. in front of platform P carried by main beams 21, 22. Gearbox 3 is located below platform P and longitudinally faces differential 16, i.e. a normal layout in tractors.
Figure 4 shows a further embodiment of the present invention wherein the same numerals already used in the above paragraphs indicate functionally identical elements to those described for embodiment of figure 1. In particular, the embodiment in figure 4 differs from that in figure 1 as follows.
In particular, figure 4 shows a hybrid drivetrain for tractor T having an additional electric motor 30 connected to differential 16 for traction of wheels or tracks W. Electric motor 30 is controlled via an inverter 31 and powered by battery pack 15. According to a preferred embodiment, electric motor 1 has a through shaft connected via clutch 17 to drive shaft S of internal combustion engine 2.
Furthermore, driveshaft S is connected in torque transfer to the through shaft of electric motor 30 via a reduction gearbox 32 such that the angular speed of electric motor 30 is lower than that of driveshaft S. Preferably, the speed ratio of reduction gearbox 32 is constant and the gearbox is downstream of clutch 17. Alternatively, reduction gearbox 32 may be upstream of clutch 17.
Alternatively, electric motor 30 is offset from differential 16 and/ or clutch 17 and is connected in torque transfer for traction via a dedicated reduction gearbox. It is also possible that power unit 1, 2 and electric motor 30 are connected to differential 16 via a reduction gear located downstream of clutch 17. In all embodiments, reduction gearbox has fixed gear ratios / discrete shifts that are selected by the driver and are not automatically selected on the basis of vehicle functioning parameters.
SERIES / PARALLEL LAYOUT - FUNCTIONING AT TRACTION In use, differential 16 receives torque from electric motor 1, internal combustion engine 2 and electric motor 30 or at least just one of the latter power units, depending on the status of decoupler 5, locking mechanism 6 and clutch 17. In particular, tractor T provides at least a higher traction torque functioning mode and a lower traction torque functioning mode. Preferably a maximum vehicle speed of the former is lower than a maximum vehicle speed of the latter.
The higher traction torque functioning mode is provided when clutch 17 is closed and electric machine 1 and/ or internal combustion engine 2, via reduction gearbox 32, provide a torque contribution for differential 16. In particular, the combined maximum torque of electric machine 1 and internal combustion engine 2 is higher than maximum torque of electric motor 30.
In particular, in higher traction torque functioning mode, the highest torque provided to differential 16 comes from electric machine 1 in peak functioning condition in order to e.g. provide uphill start at a creep speed. After a predefined tractor speed threshold, e.g. 5 km/h, internal combustion engine 2 automatically switches on and decoupler 5 provides the relative torque to driveshaft S. When both electric machine 1 and internal combustion engine 2 are on and coupled in torque transfer, the accelerator pedal operated by the driver controls torque of the internal combustion engine and electric machine 1 provides additional torque, if needed, e.g. according to the embodiments already discussed in relation to figure 1. When both electric machine 1 and internal combustion engine 2 provide driving torque, further electric machine 30 is generally off. The latter is automatically switched on in order to provide further torque, e.g. based on monitoring of functioning parameters such as tractor speed or angular speed of any driveline rotating element. Traction torque provided by electric machine 1 and internal combustion engine 2 is multiplied by reduction gear 32.
The lower traction torque functioning mode is provided when clutch 17 is open and further electric machine 30 provides traction torque.
According to a first embodiment, electric machine 30 is connected in direct drive to differential 16 and starting from stopped or braked vehicle is provided via electric machine 1 by closing clutch 17. At a predefined speed threshold, clutch 17 automatically opens and electric machine 30 provides traction torque.
As an alternative, a further reduction gear is provided to couple in torque transfer electric machine 30 to differential 16. The relative torque multiplication provides a sufficient torque level to differential 16 at start from braked or stopped vehicle when clutch 17 is open.
The accelerator pedal controls the torque level, i.e. the absorbed electric current, provided by further electric machine 30 when clutch 17 is open. The switch between the two functioning modes may be manual, e.g. via a selector operable by the driver during travel of the tractor, or automatically as discussed for the embodiment where torque at start from braked or stopped vehicle is always provided by electric motor 1.
OTHER FUNCTIONS
When clutch 17 is open, charging of battery pack 15 is provided when locking mechanism 6 is closed and, preferably, at an angular speed and/or torque level that are independent from those required by the user via the accelerator pedal.
Furthermore, via suitable manual control interface, the driver may change the angular speed of the power take-off and/or of hydraulic pump 13, both driven by electric machine 1 and/ or internal combustion engine 2.
In particular, by closing clutch 17, it is possible that internal combustion engine 2 drives differential 16 and/ or power take-off 4 and/ or hydraulic pump 13. This may for example happen in case of major electric failure of both electric machines 1, 30.
When provided on a tractor, i.e. a tractor having the framed chassis and platform shown in figure 3, electric motor 30 is located below platform P, in particular longitudinally facing rear differential 16. In order to provide such layout, driveshaft S is vertically spaced from an input shaft of differential 16 and/ or from a hub of wheels W. A suitable not-shown transmission, e.g. gears or a chain transmission, is therefore provided to transfer torque between driveshaft S and electric motor 30 and/ or differential 16. Such transmission may incorporate the speed reducing function of gearbox 32.
FURTHER PARALLEL LAYOUT
Figure 5 discloses a further embodiment of the present invention, where numerals already used for describing the preceding embodiments indicate the same functional elements of the preceding paragraphs. In particular, the layout in figure 5 differs from that in figure 1 as follows.
Crown 9 is connected to an electric machine 30' with a reduction gear ratio when the machine drives the crown. Electric machine 30' is functionally similar to electric machine 30 but is associated to planetary gear 8, 9, 10 and not downstream of the latter, as the case in the layout of figure 4. Furthermore, electric machine 30' is controlled and powered by an inverter and a battery pack, for example by battery pack 15. Gear 11 is coupled to drive power take-off 4 and/ or hydraulic pump 13. Furthermore, carrier 9 is always connected to gearbox 3, i.e. there is no clutch to selectively couple in rotation carrier 9 and gearbox 3.
During traction in a parallel functioning mode, planetary gear 8, 9, 10 combine torques from internal combustion engine 2 and electric machine 30'. According to a preferred embodiment, above a predefined speed threshold of vehicle T, internal combustion engine 2 is kept at some constant angular speed functioning points having a relatively high efficiency. In case a higher torque input is associated to the angular position of the accelerator pedal electric machine 30' provides the missing torque.
Below the predefined threshold, internal combustion engine 2 is off and decoupler 5 disconnects from driveshaft S. Furthermore, the hollow rotor and driveshaft S are angularly coupled via locking mechanism 6. An input from the accelerator pedal is processed with the highest priority by electric machine 1 and, in case additional torque is needed, electric machine 30' is switched automatically on.
Preferably, such full electric functioning can be selected via a suitable selector operable from the driver seat, e.g. on the dashboard, by the driver also above the predefined threshold. However, maximum vehicle speed in full electric mode is lower than maximum vehicle speed in the hybrid mode discussed above, at a given shift of gearbox 3. In view of the increase control capability provided by introduction of electric machine 30', gearbox 3 may have a structure with two shifts, e.g. a creep speed shift and a direct drive shift. Such simple structure is also due to the fact that reverse speed is provided by inversion of electric machine 30'.
In hybrid functioning mode, locking mechanism 6 may be open so that power take-off and/ or hydraulic pump 13 are driven at an angular speed that is independent from that of driveshaft S. When locking mechanism 6 is closed, electric machine 1 may function as a generator to recharge battery pack 15.
Decoupler 5, locking mechanism 6 and clutch 17 may differ or be the same kind of component and are preferably capable of engaging and disengaging the relative power unit during rotation and torque transmission of the relative connecting shaft.
Electric motor 30 may be an electric machine functioning also as a generator to charge battery pack 15 during braking of tractor T.

Claims

1. Work vehicle (T) comprising a traction hybrid power unit (1, 2), a hydraulic pump (13) driven by the hybrid power unit (1, 2) for powering an implement of the tractor and a power take-off (4) powered by the hybrid power unit (1, 2), wherein an electric machine (1) of the hybrid power unit has a hollow rotor housing a drive shaft (S) driven by the internal combustion engine (2) and connected in torque transfer to a differential (16) of the vehicle; an angular decoupler (5) selectively connects in rotation the drive shaft (S) to the internal combustion engine (2) and a locking mechanism (6) selectively connects in rotation the drive shaft (S) and the hollow rotor.
2. Work vehicle according to claim 1, wherein the decoupler (5) and the locking mechanism (6) are placed between the electric machine (1) and the internal combustion engine (2) along a direction parallel to a first axis of rotation of the hollow rotor and wherein a second axis of rotation of a crankshaft of the internal combustion engine (2) and the first axis of rotation are substantially parallel to a longitudinal axis of the tractor (T).
3. Work vehicle according to any of claims 1 or 2, comprising a clutch (17) downstream of said decoupler (5) and locking mechanism (6) to selectively disconnect the driveshaft (S) and the differential (16) and wherein a reduction gear (3; 32) transfers torque between clutch (17) and the differential (16).
4. Work vehicle according to any of the preceding claims, wherein a planetary gear comprises a sun gear (8) connected in torque transfer to the driveshaft (S), a crown (9) connected in torque transfer to the hollow rotor so that, when the locking mechanism (6) is closed, the sun gear (8) and the crown (9) have the same angular speed, and a carrier (10) connected in torque transfer to the clutch (17).
5. Control method of a work vehicle (T) according to any of the preceding claims, comprising the step of closing both the locking mechanism (6) and the clutch (17) and switching off the electric machine (1) so that internal combustion engine (2) drives the hydraulic pump (13) and/ or the power take-off (4) via the hollow rotor and the differential (16) via the driveshaft (S) and the clutch (17).
6. Control method of a work vehicle (T) according to any of claims 1 to 4, comprising the step of driving the electric machine (1) functioning as an alternator via the crown gear (9) that provides a braking torque so that the carrier (10) drives the differential (16) via the sun gear (8).
7. Work vehicle according to any of claims 1 to 3, wherein a further electric machine (30) is connected in torque transfer to the differential (16) via the reduction gear (32) downstream of the clutch (17).
8. Control method of a work vehicle (T) according to claim 7, comprising the step of providing a lower traction torque mode wherein clutch (17) is open, traction is provided by the further electric machine (30) and electric power is generated via the electric machine (1) and internal combustion engine (2); and the step of providing a higher traction torque mode, wherein the clutch (17) is closed and at least electric machine (1) and the internal combustion engine (2) drive the differential (16) and wherein a first maximum torque provided to the differential by at least the electric machine (1) and the internal combustion engine (2) is greater than a second maximum torque provided to the differential (16) by the further electric machine (30).
9. Work vehicle according to any of claims 1 or 2, comprising a further electric machine (30') and a planetary gear having a sun gear (8) connected in torque transfer to the driveshaft (S), a crown (9) connected in torque transfer to the further electric machine (30'), and a carrier (10) connected in torque transfer to the differential (16).
10. Work vehicle (T) according to any of claims 1, 2, 3, 4, 7, 9 further comprising a first and a second longitudinal main beams (21, 22) forming a framed chassis and a platform (P) supporting a driver's seat and carried by the main beams (21, 22); and wherein the electric machine (1) is carried by the framed chassis in a longitudinal position between the internal combustion engine (2) and the platform (P) and a battery pack (15) powering the electric machine (1) surrounds the electric machine (1) and is carried by the framed chassis.
PCT/IB2018/060174 2018-02-19 2018-12-17 Work vehicle comprising a traction hybrid power unit and control method therefor WO2019158988A1 (en)

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WO2024147774A1 (en) * 2023-01-03 2024-07-11 Turk Traktor Ve Ziraat Makineleri Anonim Sirketi A tail shaft transmission system for secondary engines

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