SE543213C2 - Hybrid Electric Powertrain, and Vehicle - Google Patents

Hybrid Electric Powertrain, and Vehicle

Info

Publication number
SE543213C2
SE543213C2 SE1851575A SE1851575A SE543213C2 SE 543213 C2 SE543213 C2 SE 543213C2 SE 1851575 A SE1851575 A SE 1851575A SE 1851575 A SE1851575 A SE 1851575A SE 543213 C2 SE543213 C2 SE 543213C2
Authority
SE
Sweden
Prior art keywords
coolant
powertrain
engine
radiator
branch
Prior art date
Application number
SE1851575A
Other languages
Swedish (sv)
Other versions
SE1851575A1 (en
Inventor
Matthias Ussner
Ola Hall
Zoltan Kardos
Original Assignee
Scania Cv Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scania Cv Ab filed Critical Scania Cv Ab
Priority to SE1851575A priority Critical patent/SE543213C2/en
Priority to DE102019008228.1A priority patent/DE102019008228B4/en
Publication of SE1851575A1 publication Critical patent/SE1851575A1/en
Publication of SE543213C2 publication Critical patent/SE543213C2/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/24—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries
    • B60L58/26—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries by cooling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/065—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P3/00—Liquid cooling
    • F01P3/12—Arrangements for cooling other engine or machine parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P3/00—Liquid cooling
    • F01P3/20—Cooling circuits not specific to a single part of engine or machine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P7/00—Controlling of coolant flow
    • F01P7/14—Controlling of coolant flow the coolant being liquid
    • F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P7/00—Controlling of coolant flow
    • F01P7/14—Controlling of coolant flow the coolant being liquid
    • F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
    • F01P7/165—Controlling of coolant flow the coolant being liquid by thermostatic control characterised by systems with two or more loops
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
    • F02G5/00—Profiting from waste heat of combustion engines, not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K9/00—Plants characterised by condensers arranged or modified to co-operate with the engines
    • F01K9/003—Plants characterised by condensers arranged or modified to co-operate with the engines condenser cooling circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P7/00—Controlling of coolant flow
    • F01P7/14—Controlling of coolant flow the coolant being liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
    • F02G5/00—Profiting from waste heat of combustion engines, not otherwise provided for
    • F02G5/02—Profiting from waste heat of exhaust gases
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/62—Heating or cooling; Temperature control specially adapted for specific applications
    • H01M10/625—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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • 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
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Abstract

A hybrid electric powertrain (1) for a vehicle (3) is disclosed. The powertrain (1) comprises a combustion engine (5), an engine coolant circuit (6) arranged to cool the combustion engine (5), a waste heat recovery system (7), and an electric propulsion system (9, 11 , 13). The waste heat recovery system (7) comprises an expander (15) and a condenser (17), the condenser (17) being arranged to be cooled by coolant flowing through a portion (21) of the engine coolant circuit (6). The powertrain (1) further comprises a cooling system (23, 25) arranged to cool at least one portion (9, 11 , 13) of the electric propulsion system (9, 11 , 13), and a heat exchanger arrangement (27, 29) configured to exchange heat between the portion (21) of the engine coolant circuit (6) and the cooling system (23, 25). The present disclosure further relates to a vehicle (3) comprising a powertrain (1).

Description

1 Hybrid Electric Powertrain, and Vehicle TECHNICAL FIELD The present disclosure relates to a hybrid electric powertrain for a vehicle comprising anelectric propulsion system and a cooling system arranged to cool at least one portion of theelectric propulsion system. The present disclosure further relates to a vehicle comprising ahybrid electric powertrain.
BACKGROUND Hybrid electric powertrains use two or more distinct types of power, such as an internalcombustion engine and an electric propulsion system. Generally, an internal combustionengine has poor energy efficiency at lower power output levels and better energy efficiencyat higher power output levels. An electric propulsion system usually has great energyefficiency at low power output levels and at high power output levels, but the storage ofelectric energy in the vehicle is usually insufficient for allowing longer time periods ofoperation at higher power output levels.
Therefore, some hybrid electric powertrains are configured to switch between electricpropulsion and combustion engine propulsion in dependence of the load such that theelectric propulsion system is operated in low load situations and the combustion engine isstarted and operated in higher load situations. Some hybrid electric powertrains areconfigured to allow simultaneous operation of the electric propulsion system and the combustion engine.
Most modern hybrid electric powertrains are capable of performing regenerative braking, inwhich at least part of the kinetic energy of the vehicle is converted into electric energy duringbraking of the vehicle. The electric energy can be stored in batteries, and/or capacitors, forsubsequent use for propulsion of the vehicle. ln this manner, the total energy efficiency of thevehicle can be improved, especially when driving in areas with many starts and stops, suchas when driving in urban areas. However, the energy saving potential of a hybrid electricpowertrain is limited, or even close to zero, when driving at constant higher speeds, such asduring highway driving.
A further advantage of hybrid electric powertrains is that they can allow pure electricpropulsion system in certain areas, such as in city centres, and other areas sensitive toemission of exhaust gases, and/or emission of noise. Therefore, some hybrid electricpowertrains are arranged to shift between pure electric propulsion and pure combustion 2 engine propulsion. This provides an advantage, especially for heavier vehicles, since thevehicle can be operated on pure electric drive when driving in certain areas, such as whendriving in urban areas, and can shift to operation using only the combustion engine whendriving at constant higher speeds, such as during highway driving. ln this manner, thepowertrain can generate low emission levels of exhaust gases and noise in sensitive areas,and the combustion engine is operated in load situations where it is most efficient, i.e. in highload situations. Moreover, the vehicle can be equipped with reasonably sized batteries. ln general, diesel engines have energy efficiency of up to 45% but more typically 30%, andpetrol engines of up to 40%, but more typically 20%. Accordingly, even when the engine isoperating at its point of maximum efficiency, most of the total heat energy released by thefuel consumed is emitted as heat without being turned into useful work, i.e. turning thecrankshaft. A large proportion of the waste heat is emitted in the form of hot exhaust gases.For this reason, some vehicles are equipped with a waste heat recovery system capable ofconverting waste heat into useful work. Most waste heat recovery systems operate in theRankine cycle and comprise a condenser, an exhaust gas heat exchanger, and an expander,wherein steam generated in the exhaust gas heat exchanger is converted into useful work bythe expander. The expander may comprise a turbine or one or more pistons and may beconnected to a shaft of the powertrain to supply useful work thereto. As an alternative, theexpander may be linked to an alternator to generate electricity. ln order to obtain a properthermal efficiency of the waste heat recovery system, the condenser thereof must be cooled.
The above described vehicle systems are capable of improving energy efficiency of vehicles.However, they are also associated with some drawbacks, such as that they add cost andcomplexity to vehicles. For example, all the above described vehicle systems require cooling.That is, a combustion engine needs a combustion engine cooling system for cooling thecombustion engine, the electrical propulsion system needs a cooling system for coolingelectrical components thereof, and the waste heat recovery system needs a cooling systemfor cooling the condenser thereof. All these cooling systems must be designed in size andcapacity to provide sufficient cooling at the highest power output of the respective system.Thus, in most operating conditions, the size and capacity of the respective cooling system isgreater than what is needed given the current power output of the vehicle system. Moreover,all these cooling systems need hoses and one or more radiators arranged to radiate heat,which may pose problems given the limited space available at the vehicle.
SUMMARY 3 lt is an object of the present invention to overcome, or at least alleviate, at least some of theabove-mentioned problems and drawbacks.
According to a first aspect of the invention, the object is achieved by a hybrid electricpowertrain for a vehicle. The powertrain comprises a combustion engine, an engine coolantcircuit arranged to cool the combustion engine, a waste heat recovery system, and anelectric propulsion system. The waste heat recovery system comprises an expander and acondenser, the condenser being arranged to be cooled by coolant flowing through a portionof the engine coolant circuit. The powertrain further comprises a cooling system arranged tocool at least one portion of the electric propulsion system, and a heat exchangerarrangement configured to exchange heat between the portion of the engine coolant circuitand the cooling system.
Thereby, a powertrain is provided capable of utilizing the cooling system of the electricpropulsion system for cooling the condenser of the waste heat recovery system. Thisbecause the powertrain comprises the heat exchanger arrangement configured to exchangeheat between the portion of the engine coolant circuit, which is arranged to cool thecondenser, and the cooling system, which is arranged to cool at least one portion of theelectric propulsion system.
Due to these features, the energy efficiency of the powertrain can be improved. Moreover,since the powertrain comprises the heat exchanger arrangement, heat can be exchangedbetween the portion of the engine coolant circuit and the cooling system in an efficientmanner without mixing coolant of the engine coolant circuit and the cooling system of theelectric propulsion system. Accordingly, conditions are provided for using different types ofcoolant in the engine coolant circuit and in the cooling system of the electric propulsionsystem.
Moreover, the combustion engine and the electric propulsion system of a hybrid electricpowertrain rarely operates simultaneously at high power levels. On the contrary, somepowertrains are arranged to operate the combustion engine and the electric propulsionsystem separately, which is the case according to some embodiments of the presentdisclosure. When the powertrain is operating the combustion engine at high power levels andthe electric propulsion system is inactive, the cooling demands of the combustion engine andof the condenser of the waste heat recovery system are high. 4 ln these operating conditions, the cooling system of the electric propulsion system is notneeded for cooling the electric propulsion system since the electric propulsion system is notoperating. lnstead, in these operating conditions, the condenser of the waste heat recoverysystem can be cooled using the cooling system of the electric propulsion system. lnoperating conditions where the powertrain is operating the electric propulsion system and thecombustion engine is inactive, there is no need for cooling the condenser of the waste heatrecovery system because the combustion engine and the waste heat recovery system areinactive. Accordingly, the cooling system of the electric propulsion system can be used forcooling the electric propulsion system in some operating conditions and can be used forcooling the condenser of the waste heat recovery system in some other operating conditions.
Moreover, as understood from the above, the radiator of the engine coolant circuit can besmaller and can be designed to have lower capacity than would be required otherwise forobtaining sufficient cooling of the combustion engine and the condenser of the waste heatrecovery system. Moreover, in this manner, the condenser of the waste heat recovery systemcan be sufficiently cooled over a wider operational range of the internal combustion engine,which in turn potentially improves the energy efficiency of the waste heat recovery system.
Furthermore, the powertrain provides conditions for a more efficient utilization of availableradiators of the powertrain. Moreover, the powertrain provides conditions for rapid switchingbetween different cooling sources for the condenser, which thus can reduce lag in coolingperformance. ln summary, as described above, the powertrain provides conditions for improvedperformance and energy efficiency, and conditions are provided for efficient utilization ofspace and efficient utilization of available radiators of a vehicle.
Accordingly, a powertrain is provided overcoming, or at least alleviating, at least some of theabove-mentioned problems and drawbacks. As a result, the above-mentioned object isachieved.
Optionally, the electric propulsion system comprises an electric machine, a battery, andpower electronics, wherein the cooling system comprises a first coolant circuit arranged tocool at least one of the electric machine and the power electronics, and a first heatexchanger configured to exchange heat between the portion of the engine coolant circuit andthe first coolant circuit. Thereby, a powertrain is provided capable of utilizing the first coolantcircuit, which is arranged to cool at least one of the electric machine and the power electronics, for cooling the condenser of the waste heat recovery system. ln this manner, thepowertrain provides conditions for an efficient utilization of space, conditions for efficientutilization of available radiators, and conditions for improved performance and energyefficiency of the powertrain.
Optionally, the first coolant circuit comprises a first valve arranged to regulate the flow ofcoolant through the first heat exchanger. Thereby, the flow of coolant through the first heatexchanger, and thus also the level of cooling of the condenser by the first coolant circuit, canbe regulated in a simple and efficient manner.
Optionally, the first coolant circuit comprises a first coolant branch, and wherein the first heatexchanger is arranged in the first coolant branch. Thereby, conditions are provided forcooling the condenser, using the first coolant circuit, without significantly affecting thetemperature and cooling performance of the electric machine and/or the power electronics.
Optionally, the first coolant branch comprises a branch inlet arranged upstream of the electricmachine and/or the power electronics. Thereby, the condenser can be cooled using the firstcoolant circuit, without significantly affecting the temperature and cooling performance of theelectric machine and/or the power electronics. Moreover, it is ensured that the first heatexchanger is supplied with coolant having a low temperature.
Optionally, the first coolant branch comprises a branch inlet arranged downstream of theelectric machine and/or the power electronics. Thereby, a simple and efficient arrangement isprovided. Moreover, as explained herein, the combustion engine and the electric propulsionsystem of a hybrid electric powertrain rarely operates simultaneously at high power levels.Thus, in most cases, is ensured that the first heat exchanger is supplied with coolant having a low temperature.
Optionally, the cooling system comprises a second coolant circuit arranged to cool thebattery, and wherein the powertrain comprises a second heat exchanger arranged toexchange heat between the portion of the engine coolant circuit and the second coolantcircuit. Thereby, a powertrain is provided capable of utilizing the second coolant circuit, whichis arranged to cool the battery, for cooling the condenser of the waste heat recovery system.Accordingly, the powertrain provides conditions for an efficient utilization of space, conditionsfor efficient utilization of available radiators, and conditions for improved performance andenergy efficiency of the powertrain. 6 Moreover, conditions are provided for using different types of coolant in the first and secondcoolant circuits. ln this manner, the cooling performance of the respective first and secondcoolant circuits can be improved, and the battery can be coo|ed to different temperaturelevels than the electric machine and power electronics, in a simple and efficient manner.
Moreover, in operating conditions where the temperature of the battery is below maximumallowed levels, the battery can be used as a buffer in transient modes for reducing thetemperature of the condenser. ln this manner, the performance and energy efficiency of thepowertrain can be further improved.
Optionally, the second coolant circuit comprises a second valve arranged to regulate the flowof coolant through the second heat exchanger. Thereby, the flow of coolant through thesecond heat exchanger, and thus also the level of cooling of the condenser by the second coolant circuit, can be regulated in a simple and efficient manner.
Optionally, the second heat exchanger is arranged in a second coolant branch of the secondcoolant circuit, and wherein the second coolant branch comprises an inlet arranged upstreamof the battery. Thereby, the condenser can be coo|ed using the second coolant circuit,without significantly affecting the temperature and cooling performance of the battery.Moreover, it is ensured that the second heat exchanger is supplied with coolant having a low tempefatUfe.
Optionally, the portion of the engine coolant circuit is an engine coolant branch of the enginecoolant circuit. Thereby, conditions are provided for a higher degree of control of the coolingof the condenser. Moreover, conditions are provided for cooling the condenser using thecooling system of the electric propulsion system in a manner independent of the cooling ofthe combustion engine, as is further explained herein.
Optionally, the engine coolant circuit comprises an engine radiator, and wherein the enginecoolant branch comprises a branch inlet arranged downstream of the engine radiator andupstream of a coolant inlet of the combustion engine. Thereby, it is ensured that coolanthaving a low temperature is supplied to the condenser.
Optionally, the engine coolant circuit comprises a radiator line arranged to conduct coolant tothe engine radiator, a bypass line arranged to conduct coolant past the engine radiator, a firstvalve device arranged to receive coolant from a coolant line of the engine coolant circuit and direct the coolant to the radiator line and the bypass line, and a second valve device 7 arranged to receive coolant from the bypass line and direct at least part of coolant flow fromthe bypass line to the branch inlet. Thereby, a powertrain is provided in which it is ensuredthat coolant can be supplied to the engine coolant branch also when the first valve directscoolant to the bypass line.
Optionally, the engine coolant circuit further comprises a radiator outlet line arranged toconduct at least part of coolant flow from the engine radiator to the branch inlet. Thereby, apowertrain is provided in which it is ensured that coolant can be supplied to the enginecoolant branch also when the first valve directs coolant to the radiator line.
Optionally, the engine coolant branch comprises a third valve device and a branch bypassline connecting portions of the engine coolant branch, and wherein the third valve device iscontrollable to a position in which flow of coolant is allowed through the branch bypass lineso as to form a separate coolant circuit through the branch bypass line and the enginecoolant branch. Thereby, a powertrain is provided capable of forming a separate coolantcircuit for cooling the condenser, in a simple and efficient manner, thus allowing thecondenser to be cooled using the cooling system of the electric propulsion system in amanner independent of the cooling of the combustion engine. ln this manner, the powertrainprovides conditions for a further efficient utilization of space, further efficient utilization ofavailable radiators, and further improved performance and energy efficiency of thepowertrain.
Optionally, the engine coolant branch comprises a coolant pump. Thereby, the condensercan be cooled by the separate coolant circuit in an efficient manner.
Optionally, the engine coolant circuit comprises an engine radiator, and wherein the coolingsystem comprises at least one radiator arranged in front of the engine radiator. Thereby, itcan be ensured that the cooling system of the electric propulsion system cools the electricpropulsion system, and/or the condenser of the waste heat recovery system, using coolant having low temperature.
Optionally, the powertrain comprises a charge air cooler arranged between the at least oneradiator and the engine radiator. Thereby, it can be ensured that the charge air coolerobtains sufficient cooling while it is ensured that the cooling system of the electric propulsionsystem cools the electric propulsion system, and/or the condenser of the waste heat recovery system, using coolant having low temperature. 8 Optionally, the powertrain comprises a charge air cooler, and wherein the cooling systemcomprises at least one radiator between the charge air cooler and the engine radiator and atleast one radiator in front of the charge air cooler. Thereby, it can be ensured that the chargeair cooler obtains sufficient cooling while it is ensured that the cooling system of the electricpropulsion system cools at least a portion of the electric propulsion system, and/or thecondenser of the waste heat recovery system, using coolant having low temperature.
Optionally, the at least one radiator in front of the charge air cooler is a radiator of the second coolant circuit. Thereby, it can be ensured that the battery is cooled using coolant having low tempefatUfe.
According to a second aspect of the invention, the object is achieved by a vehicle comprisinga powertrain according to some embodiments of the present disclosure.
Since the vehicle comprises a powertrain according to some embodiments, a vehicle isprovided having conditions for efficient utilization of space, efficient utilization of availableradiators, and improved performance and energy efficiency.
Accordingly, a vehicle is provided overcoming, or at least alleviating, at least some of theabove-mentioned problems and drawbacks. As a result, the above-mentioned object isachieved.
Further features of, and advantages with, the present invention will become apparent whenstudying the appended claims and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS Various aspects of the invention, including its particular features and advantages, will bereadily understood from the example embodiments discussed in the following detaileddescription and the accompanying drawings, in which: Fig. 1 schematically illustrates a hybrid electric powertrain, according to some embodiments,Fig. 2 schematically illustrates a hybrid electric powertrain, according to some furtherembodiments, and Fig. 3 illustrates a vehicle, according to some embodiments.
DETAILED DESCRIPTION 9 Aspects of the present invention will now be described more fully. Like numbers refer to likeelements throughout. Well-known functions or constructions will not necessarily be describedin detail for brevity and/or clarity.
Fig. 1 schematically illustrates a hybrid electric powertrain 1, according to someembodiments. The hybrid electric powertrain 1 is configured provide motive power to avehicle comprising the powertrain 1. The hybrid electric powertrain 1 is in some places hereinreferred to as “the powertrain 1” for the reason of brevity and clarity. The powertrain 1comprises a combustion engine 5. The combustion engine 5 may be an internal combustionengine such as for example a compression ignition engine, such as a diesel engine, or anOtto engine with a spark-ignition device, wherein the Otto engine may be configured to runon gas, petrol, alcohol, similar fuels, or combinations thereof. The powertrain 1 comprises anengine coolant circuit 6 arranged to cool the combustion engine 5. The engine coolant circuit6 comprises an engine radiator 46 and a coolant pump 49 arranged to pump coolant throughthe engine coolant circuit 6.
Moreover, the powertrain 1 further comprises an electric propulsion system 9, 11, 13configured to, at least selectively, provide motive power to a vehicle comprising thepowertrain 1. According to the illustrated embodiments, the electric propulsion system 9, 11,13 comprises an electric machine 9, a battery 11, and power electronics 13. The battery 11 isarranged to supply electricity to the electric machine 9 by an amount controlled by the powerelectronics 13.
The powertrain 1 comprises a waste heat recovery system 7. According to the illustratedembodiments, the waste heat recovery system 7 comprises an expander 15, a condenser17, an expansion tank 83, a working media pump 85, and a heat collector 81. The heatcollector 81 may also be referred to as a boiler or an evaporator. The working media pump85 is arranged to pump working media through the waste heat recovery system 7. The heatcollector 81 may for example be arranged in an exhaust pipe of the combustion engine 5 andmay be arranged to transfer heat from exhaust gasses of the combustion engine 5 to theworking media of the waste heat recovery system 7. ln the heat collector 81, the workingmedia is heated to a temperature in which the working media evaporates from liquid phaseinto gaseous phase. The gaseous working media is transferred to the expander 15. ln theexpander 15, the temperature and the pressure of the working media is partially convertedinto useful work. According to the illustrated embodiments, a rotor of the expander 15 ismechanically connected to a crankshaft of the combustion engine 5, via a transmission 87.
According to further embodiments, the expander 15 may provide useful work in anothermanner, such as for example by driving an alternator producing electricity.
The working media of the waste heat recovery system 7 flows out from the expander 15 andinto the condenser 17. ln the condenser 17, the temperature of the working media is furtherreduced, and gaseous working media is condensed back into liquid phase. From thecondenser 17, the working media is pumped to the heat collector 81 by the working mediapump 85. The expansion tank 83 acts as a reservoir holding working media and acts as apressure reservoir for the working media in the waste heat recovery system 7, whichfacilitates condensation of working media also in cases where it is difficult to lower the temperature in a sufficient manner.
According to the present disclosure, the condenser 17 is arranged to be cooled by coolantflowing through a portion 21 of the engine coolant circuit 6. Moreover, the powertrain 1comprises a cooling system 23, 25 arranged to cool at least one portion 9, 11, 13 of theelectric propulsion system 9, 11, 13. Furthermore, the powertrain 1 comprises a heatexchanger arrangement 27, 29 configured to exchange heat between the portion 21 of theengine coolant circuit 6 and the cooling system 23, 25. ln this manner, a powertrain 1 isprovided capable of utilizing the cooling system 23, 25 of the electric propulsion system 9,11, 13 for cooling the condenser 17 of the waste heat recovery system 7.
According to the illustrated embodiments, the cooling system 23, 25 comprises a first coolantcircuit 23 arranged to cool the electric machine 9 and the power electronics 13. The firstcoolant circuit 23 comprises a coolant pump 24 arranged to pump coolant through the firstcoolant circuit 23. The coolant pump 24 may be powered by an electric motor. The firstcoolant circuit 23 further comprises a radiator arrangement 70, 70' arranged to radiate heatfrom, i.e. cool, coolant in the first coolant circuit 23. According to the illustrated embodiments,the radiator arrangement 70, 70' comprises two radiators 70, 70' arranged in series. The tworadiators 70, 70' may be combined in a u-flow radiator or similar. According to furtherembodiments, the radiator arrangement 70, 70' may comprise one radiator. Moreover,according to the illustrated embodiments, the first coolant circuit 23 is arranged to cool acabin heater condenser 90, an electrical air compressor system 92, and a condenser 94 of abattery refrigeration circuit 93.
According to the illustrated embodiments, the heat exchanger arrangement 27, 29 comprisesa first heat exchanger 27 configured to exchange heat between the portion 21 of the enginecoolant circuit 6 and the first coolant circuit 23. As can be seen in Fig. 1, the first heat 11 exchanger 27 is arranged upstream of the condenser 17 in the portion 21 of the enginecoolant circuit 6. ln this manner, coolant flowing through the portion 21 of the engine coolantcircuit 6 can be further cooled, by the first heat exchanger 27, before the coolant is flowing tothe condenser 17. Accordingly, the first coolant circuit 23 can be utilized to cool the condenser 17 in an efficient manner.
The first coolant circuit 23 comprises a first valve 31. The first valve 31 is arranged toregulate the flow of coolant through the first heat exchanger 27. Moreover, the first coolantcircuit 23 comprises a first coolant branch 33. The first heat exchanger 27 is arranged in thefirst coolant branch 33 of the first coolant circuit 23. According to the embodiments illustratedin Fig. 1, the first coolant branch 33 comprises a branch inlet 35 arranged upstream of theelectric machine 9 and the power electronics 13. ln this manner, heat can be exchangedfrom the portion 21 of the engine coolant circuit 6 to the first coolant circuit 23 withoutsignificantly affecting the temperature and the cooling performance of the electric machine 9and the power electronics 13. Furthermore, it is ensured that coolant having a lowtemperature is supplied to the first heat exchanger 27.
Moreover, according to the illustrated embodiments, the first valve 31 is positioned at thebranch inlet 35 of the first coolant branch 33. The first valve 31 comprises a first outlet 31'fluidly connected to coolant portions of the electric machine 9 and the power electronics 13and a second outlet 31 ” fluidly connected to the branch inlet 35. Coolant is ducted fromcoolant portions of the electric machine 9 and the power electronics 13 via a return line 34.The return line 34 is fluidly connected to the radiator arrangement 70, 70' in a mannerbypassing the first heat exchanger 27. According to the illustrated embodiments, the firstvalve 31 is an electronically controlled valve which can be controlled to a first state in whichthe first valve 31 supplies coolant to the first outlet 31' and blocks coolant from flowingthrough the second outlet 31 and a second state in which the first valve 31 supplies coolantto the second outlet 31 ” and blocks coolant from flowing through the first outlet 31 '_Furthermore, the first valve 31 may allow a gradual control to states between the first andsecond states to allow a gradual control of flow through the first and second outlets 31 ', 31ln this manner, the flow rate of coolant flowing through the first heat exchanger 27 can beregulated with high degree of control.
Furthermore, as explained above, it is rare that the combustion engine 5 and the electricpropulsion system 9, 11, 13 operates simultaneously, or at least with high power output fromboth systems simultaneously. ln addition, according to some embodiments of the presentdisclosure, the powertrain 1 is arranged to operate the combustion engine 5 and the electric 12 propulsion system 9, 11, 13 separately. Thus, in operating conditions where the powertrain 1is operating the combustion engine 5 and the electric propulsion system 9, 11, 13 is inactive,the components 9, 11, 13 of the electric propulsion system 9, 11, 13 generates no heat andhave no need for cooling. ln operating conditions where the powertrain 1 is operating theelectric propulsion system 9, 11, 13 and the combustion engine 5 is inactive, the combustionengine 5 and the condenser 17 of the waste heat recovery system 7 have no need forcooling. As understood from the above, in operating conditions where the powertrain 1 isoperating the electric propulsion system 9, 11, 13 and the combustion engine 5 is inactive,the first valve 31 may be controlled to positions where first valve 31 mainly controls coo|antflow to the first outlet 31 '_ ln this manner, the electric machine 9 and the power electronics 13are efficiently cooled by the first coo|ant circuit 23. However, if the cooling demand of theelectric machine 9 and the power electronics 13 is low, the first valve 31 may also becontrolled to positions where first valve 31 controls coo|ant flow to the second outlet 31” soas to totally or partially bypass the electric machine 9 and the power electronics 13. lnoperating conditions where the powertrain 1 is operating the combustion engine 5 and theelectric propulsion system 9, 11, 13 is inactive, the first valve 31 may be controlled topositions where first valve 31 mainly controls coo|ant flow to the second outlet 31 ln thismanner, the condenser 17 of the waste heat recovery system 7 is efficiently cooled by thefirst coo|ant circuit 23.
According to the illustrated embodiments, the cooling system 23, 25 further comprises asecond coo|ant circuit 25. The second coo|ant circuit 25 is arranged to cool the battery 11.The second coo|ant circuit 25 comprises a coo|ant pump 26 arranged to pump coo|antthrough the second coo|ant circuit 25. The coo|ant pump 26 may be powered by an electricmotor. The second coo|ant circuit 25 further comprises a radiator 74 arranged to radiate heatfrom, i.e. cool, coo|ant in the second coo|ant circuit 25. Moreover, according to the illustratedembodiments, the heat exchanger arrangement 27, 29 comprises a second heat exchanger29 arranged to exchange heat between the portion 21 of the engine coo|ant circuit 6 and thesecond coo|ant circuit 25. As can be seen in Fig. 1, the second heat exchanger 29 isarranged upstream of the condenser 17 in the portion 21 of the engine coo|ant circuit 6. lnthis manner, coo|ant flowing through the portion 21 of the engine coo|ant circuit 6 can befurther cooled, by the second heat exchanger 29, before the coo|ant is flowing to thecondenser 17. Accordingly, the second coo|ant circuit 25 can be utilized to cool the condenser 17 in an efficient manner.
The second coo|ant circuit 25 comprises a second valve 37. The second valve 37 isarranged to regulate the flow of coo|ant through the second heat exchanger 29. Moreover, 13 the second coolant circuit 25 comprises a second coolant branch 39, wherein the secondheat exchanger 29 is arranged in the second coolant branch 39. The second coolant branch39 comprises a branch inlet 41 arranged upstream of the battery 11 and a branch outletdownstream of the battery 11. ln this manner, heat can be exchanged from the portion 21 ofthe engine coolant circuit 6 to the second coolant circuit 25 without significantly affecting thetemperature and the cooling performance of the battery 11.
Moreover, according to the illustrated embodiments, the second valve 37 is positioned at thebranch inlet 41 of the second coolant branch 39 and comprises a first outlet 37' fluidlyconnected to coolant portions of the battery 11 and a second outlet 37” fluidly connected tothe branch inlet 41 of the second coolant branch 39. According to the illustratedembodiments, the second valve 37 is an electronically controlled valve which can becontrolled to a first state in which the second valve 37 supplies coolant to the first outlet 37'and blocks coolant from flowing through the second outlet 37”, and a second state in whichthe second valve 37 supplies coolant to the second outlet 37” and blocks coolant fromflowing through the first outlet 37”. Furthermore, the second valve 37 may allow a gradualcontrol of flow through the first and second outlets 37”, 37”. ln this manner, the flow rate ofcoolant flowing through the second heat exchanger 29 can be regulated with high degree ofcontrol. ln operating conditions where the powertrain 1 is operating the electric propulsion system 9,11, 13 and the combustion engine 5 is inactive, the second valve 37 may be controlled topositions where second valve 37 mainly controls coolant flow to the first outlet 37”. ln thismanner, the battery 11 can be efficiently cooled by the second coolant circuit 25. However, ifthe cooling demand of the battery 11 is low, the second valve 37 may also be controlled topositions where second valve 37 controls coolant flow to the second outlet 37” so as tototally or partially bypass the battery 11. Moreover, in operating conditions where thepowertrain 1 is operating the combustion engine 5 and the electric propulsion system 9, 11,13 is inactive, the second valve 37 may be controlled to positions where second valve 37mainly controls coolant flow to the second outlet 37”. ln this manner, the condenser 17 of thewaste heat recovery system 7 is efficiently cooled by the second coolant circuit 25.
As indicated above, according to the illustrated embodiments, the powertrain 1 furthercomprises a battery refrigeration circuit 93. The battery refrigeration circuit 93 is arranged tofurther lower the temperature of coolant in the second coolant circuit 25. The batteryrefrigeration circuit 93 comprises a compressor 98, a condenser 94, an expansion valve 95,and an evaporator 96. The evaporator 96 may also be referred to as a chiller. The 14 Compressor 98 compresses working media in the battery refrigeration circuit 93. Thecompressed working media is partially cooled by the condenser 94. Then the working mediais expanded by the expansion valve 95. As a result, the temperature of the working media issignificantly reduced. The working medium cools coolant of the second coolant circuit 25upon evaporation in the evaporator 96. ln this manner, it can be ensured that the battery 11is sufficiently cooled also in high load situations and in situations with high ambient tempefatUfeS.
As can be seen in Fig. 1, the evaporator 96 of the battery refrigeration circuit 93 is arrangedupstream of the branch inlet 41 of the second coolant branch 39. ln this manner, the batteryrefrigeration circuit 93 can also be utilized for further cooling the condenser 17 of the wasteheat recovery system 7. Thereby, condensation of working medium in the condenser 17 canbe further ensured even at higher load situations of the combustion engine 5 and of thewaste heat recovery system 7.
Moreover, as can be seen in Fig. 1, the second coolant circuit comprises a heater 44arranged in a bypass line bypassing the radiator 74 of the second coolant circuit 25. Theheater 44 can be used to heat coolant of the second coolant circuit 25 in order to heat thebattery 11 when needed, such as at cold starts at lower ambient temperatures.
According to the illustrated embodiments, the portion 21 of the engine coolant circuit 6, asreferred to therein, is an engine coolant branch 45 of the engine coolant circuit 6. The enginecoolant branch 45 comprises a branch inlet 47 arranged downstream of the engine radiator46 and upstream of a coolant inlet 48 of the combustion engine 5. Thereby, it is ensured thatcoolant having a low temperature is flowing into the engine coolant branch 45 towards thecondenser 17.
The engine coolant circuit 6 further comprises a radiator line 51 arranged to conduct coolantto the engine radiator 46 and a bypass line 53 arranged to conduct coolant past the engineradiator 46. Moreover, the engine coolant circuit 6 comprises a first valve device 55 arrangedto receive coolant from a coolant line 57 of the engine coolant circuit 6 and direct the coolantto the radiator line 51 and the bypass line 53. The first valve device 55 may comprise aconventional thermostat. As indicated in Fig. 1, the coolant line 57 may be fluidly connectedto a coolant outlet of the combustion engine 5. According to the illustrated embodiments, theengine coolant circuit 6 comprises a second valve device 61 arranged to receive coolantfrom the bypass line 53 and direct at least part of coolant flow from the bypass line 53 to thebranch inlet 47. Thus, in situations where the first valve device 55 directs coolant to the bypass line 53, such as when coolant at the first valve device 55 is lower than a thresholdtemperature, coolant can flow from the coolant line 57, through the bypass line 53 and thesecond valve device 61, and into the engine coolant branch 45, via the branch inlet 47.
Moreover, as indicated in Fig. 1, the engine coolant circuit 6 comprises a radiator outlet line59 arranged to conduct at least part of coolant flow from the engine radiator 46 to the branchinlet 47. Thereby, in situations where the first valve device 55 directs coolant to the radiatorline 51, such as when coolant at the first valve device 55 is higher than a thresholdtemperature, coolant can flow from the coolant line 57, through the radiator line 51 into theengine radiator 46, and out from the engine radiator 46 through the radiator outlet line 59 intothe into the engine coolant branch 45, via the branch inlet 47. Accordingly, in this manner, itcan be ensured that coolant having a low temperature is ducted into the portion 21 of theengine coolant circuit 6 regardless of the opening state of the first valve device 55.
The engine coolant branch 45 comprises a branch outlet 47' connected to an inlet of thecoolant pump 49 of the engine coolant circuit 6. Thus, according to the illustratedembodiments, coolant flowing into the branch inlet 47 flows through the second heatexchanger 29 and through the first heat exchanger 27 where the temperature of the coolantcan be reduced by the first and second coolant circuits 23, 25 respectively. Then, the coolantflows through the condenser 17 of the waste heat recovery system 7 to cool and condensateworking media in the waste heat recovery system 7. The coolant is ducted from thecondenser 17 to the inlet of the coolant pump 49 of the engine coolant circuit 6 from where itis further pumped through the engine coolant circuit 6.
According to the embodiments illustrated in Fig. 1, all radiators 70, 70', 74 of the coolingsystem 23, 25 of the electric propulsion system 9, 11, 13 are arranged in front of the engineradiator 46. That is, the radiators 46, 72, 70, 70', 74 of the powertrain 1 are configured to besubjected to an airflow having an air flow direction. The air flow direction may be opposite toa forward direction of travel of the vehicle comprising the powertrain 1. As an alternative, orin addition, the powertrain 1 may comprise one or more cooling fans arranged to selectivelyblow air through the radiators 46, 72, 70, 70', 74 in the air flow direction. Thus, according tothe embodiments illustrated in Fig. 1, all radiators 70, 70', 74 of the cooling system 23, 25 ofthe electric propulsion system 9, 11, 13 are arranged in front of the engine radiator 46 seenin the air flow direction, i.e. upstream of the engine radiator 46 relative the air flow direction.
Moreover, the powertrain 1 comprises a charge air cooler 72 arranged between the radiators70, 70', 74 of the cooling system 23, 25 and the engine radiator 46, i.e. the charge air cooler 16 72 is arranged downstream of the radiators 70, 70', 74 of the cooling system 23, 25 andupstream of the engine radiator 46 relative the air flow direction. The charge air cooler 72 isarranged to cool air compressed by a supercharger of the combustion engine 5 before the airis ducted to an in|et of the combustion engine 5. The supercharger is not illustrated in Fig. 1for the reason of brevity and clarity. The fuel efficiency and the performance of thecombustion engine 5 is improved by cooling the in|et air of the combustion engine 5 in thecharge air cooler 72.
Since all radiators 70, 70', 74 of the cooling system 23, 25 of the electric propulsion system9, 11, 13 are arranged in front of the engine radiator 46, and in front of the charge air cooler72 seen in the air flow direction, it is ensured that the cooling system 23, 25 of the electricpropulsion system 9, 11, 13 is able to cool components 9, 11, 13 of the electric propulsionsystem 9, 11, 13, and is able to cool the condenser 17 of the waste heat recovery system 7, using coolant having a low temperature.
Fig. 2 schematically illustrates a hybrid electric powertrain 1, according to some furtherembodiments. The powertrain 1 according to the embodiments illustrated in Fig. 2 comprisesthe same features, functions, and advantages as the powertrain 1 according to theembodiments illustrated in Fig. 1, with some differences explained below.
According to the embodiments illustrated in Fig. 2, the first coolant branch 33 comprises abranch in|et 35 arranged downstream of the electric machine 9 and the power electronics 13.ln these embodiments, the first valve 31 comprises a first outlet 31' f|uidly connected to areturn line 34. The return line 34 is f|uidly connected to the radiator arrangement 70, 70' in amanner bypassing the first heat exchanger 27. The first valve 31 comprises a second outlet31” f|uidly connected to the branch in|et 35. Also in these embodiments, the first valve 31 isan electronically controlled valve which can be controlled to a first state in which the firstvalve 31 supplies coolant to the first outlet 31' and blocks coolant from flowing through thesecond outlet 31 and a second state in which the first valve 31 supplies coolant to thesecond outlet 31” and blocks coolant from flowing through the first outlet 31 '_ Furthermore,the first valve 31 may allow a gradual control of flow through the first and second outlets 31 ',31 ln this manner, the flow rate of coolant flowing through the first heat exchanger 27 canbe regulated with high degree of control.
Furthermore, as explained above, it is rare that the combustion engine 5 and the electricpropulsion system 9, 11, 13 operates simultaneously, or at least with high power output fromboth systems simultaneously. ln addition, according to some embodiments of the present 17 disclosure, the powertrain 1 is arranged to operate the combustion engine 5 and the electricpropulsion system 9, 11, 13 separately. Thus, in operating conditions where the powertrain 1is operating the combustion engine 5 and the electric propulsion system 9, 11, 13 is inactive,the components 9, 11, 13 of the electric propulsion system 9, 11, 13 generates no heat.Thereby, it is ensured that coolant having a low temperature can be supplied to the first heatexchanger 27, via the first coolant circuit 23, to cool the condenser 17. ln operatingconditions where the powertrain 1 is operating the electric propulsion system 9, 11, 13 andthe combustion engine 5 is inactive, the first coolant circuit 23 can be used to coolcomponents 9, 13 of the electric propulsion system 9, 11, 13 in an efficient manner. ln theseoperating conditions, there is no need for cooling the condenser 17 of the waste heatrecovery system 7 because the combustion engine 5 and the waste heat recovery system 7 are inactive.
Another difference between the embodiments i||ustrated in Fig. 1 and Fig. 2 is that accordingto the embodiments i||ustrated in Fig. 2, the engine coolant branch 45 comprises a third valvedevice 63 and a branch bypass line 65 connecting portions of the engine coolant branch 45.The third valve device 63 is controllable to a position in which flow of coolant is allowedthrough the branch bypass line 65 so as to form a separate coolant circuit through the branchbypass line 65 and the engine coolant branch 45. According to the i||ustrated embodiments,when the third valve device 63 is in this position, the third valve device 63 blocks flow ofcoolant from the branch inlet 47 and instead allows flow of coolant through the branchbypass line 65. Moreover, as can be seen in Fig. 2, the engine coolant branch 45 comprisesa coolant pump 43. The coolant pump 43 is arranged such that the coolant pump 43 canpump coolant through the separate coolant circuit formed by the branch bypass line 65 andthe engine coolant branch 45. ln this manner, heat exchange can occur between thecondenser 17 of the waste heat recovery system 7 and the first and second heat exchangers27, 29 in a manner independent of the rest of the engine coolant circuit 6, and thus also in amanner independent of the cooling of the combustion engine 5.
Accordingly, due to these features, the condenser 17 can be cooled using the first andsecond coolant circuit 23, 25 in a manner independent of the cooling of the combustionengine 5 and different temperatures of coolant is allowed in the engine coolant branch 45and in the rest of the engine coolant circuit 6. As a further result, it can be ensured that thecombustion engine 5 obtains sufficient cooling during high load operating conditions.
Another difference between the embodiments i||ustrated in Fig. 1 and Fig. 2 is that accordingto the embodiments i||ustrated in Fig. 2, the cooling system 23, 25 comprises at least one 18 radiator 70, 70' between the charge air cooler 72 and the engine radiator 46 and at least oneradiator 74 in front of the charge air cooler 72 seen in the flow direction. According to theillustrated embodiments, the radiator 74 in front of the charge air cooler 72 is a radiator 74 ofthe second coo|ant circuit 25. Due to these features, the cooling performance of the chargeair cooler 72 is improved. Moreover, it is ensured that the battery 11 can be cooled with coo|ant having a low temperature.
According to some embodiments of the present disclosure, the first valve 31 may bepositioned at another position in the first coo|ant circuit 23, than at the branch inlet 35 of thefirst coo|ant branch 33, and still achieve all, or some of, the above described functions. As an example, the first valve 31 may be positioned at a branch outlet of the first coo|ant branch 33.
Likewise, the second valve 37 may be positioned at another position in the second coo|antcircuit 25, than at the branch inlet 41 of the second coo|ant branch 39, and still achieve all, orsome of, the above described functions. As an example, the second valve 37 may bepositioned at a branch outlet of the second coo|ant branch 39.
According to some embodiments of the present disclosure, the powertrain 1 comprises acontrol unit configured to control operation of one or more pumps 24, 26, 43, 85 of thepowertrain 1, and/or configured to control opening states of one or more valves 31, 37, 55,61, 63 of the powertrain 1. The control unit may be configured to control operation of the oneor more pumps 24, 26, 43, 85, and/or to control opening states of one or more valves 31, 37,55, 61, 63, in dependence of the operating state of the combustion engine 5, the waste heatrecovery system 7, and/or the electric propulsion system 9, 11, 13, as well as in dependenceof a current, or predicted, cooling demand of one or more components 5, 9, 11, 13, 17 of thepowertrain 1. Such a control unit is not illustrated in Fig. 1 and Fig. 2 for the reason of brevityand clarity.
Fig. 3 illustrates a vehicle 3 according to some embodiments. The vehicle 3 may comprise apowertrain 1 according to the embodiments illustrated in Fig. 1, or a powertrain 1 accordingto the embodiments illustrated in Fig. 2. The powertrain 1 is arranged to provide motivepower to the vehicle 3, via wheels 99 of the vehicle 3. According to the illustratedembodiments, the vehicle 3 is a truck. However, according to further embodiments, thevehicle 3, as referred to herein, may be another type of manned or unmanned vehicle forland or water based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car,a ship, a boat, or the like. 19 It is to be understood that the foregoing is illustrative of various example embodiments andthat the invention is defined only by the appended claims. A person skilled in the art willrealize that the example embodiments may be modified, and that different features of theexample embodiments may be combined to create embodiments other than those describedherein, without departing from the scope of the present invention, as defined by the appended claims.
As used herein, the term "comprising" or "comprises" is open-ended, and includes one ormore stated features, elements, steps, components or functions but does not preclude thepresence or addition of one or more other features, elements, steps, components, functions or groups thereof.

Claims (21)

1. Claims 1. A hybrid electric powertrain (1 ) for a vehicle (3), wherein the powertrain (1) comprises:- a combustion engine (5),- an engine coolant circuit (6) arranged to cool the combustion engine (5),- a waste heat recovery system (7), and- an electric propulsion system (9, 11, 13),wherein the waste heat recovery system (7) comprises an expander (15) and acondenser (17), condenser (17) being arranged to be cooled bycoolant flowing through a portion (21) of the engine coolant circuit (6),wherein the powertrain (1 ) further comprises:- a coo|ing system (23, 25) arranged to cool at least one portion (9, 11, 13) of theelectric propulsion system (9, 11, 13), and- a heat exchanger arrangement (27, 29) configured to exchange heat between the portion (21) of the engine coolant circuit (6) and the coo|ing system (23, 25). The powertrain (1) according to claim 1, the electricpropulsion system (9, 11, 13) comprises an electric machine (9), a battery (11), andpower electronics (13). The powertrain (1) according to claim 2, the coo|ingsystem (23, 25) comprises a first coolant circuit (23) arranged to cool at least one of theelectric machine (9) and the power electronics (13), and a first heat exchanger (27)configured to exchange heat between the portion (21) of the engine coolant circuit (6) and the first coolant circuit (23). The powertrain (1) according to claim 3, charactæršzæd in thatwherešn the first coolantcircuit (23) comprises a first valve (31) arranged to regulate the flow of coolant through the first heat exchanger (27). The powertrain (1) according to claim 3 or 4, charamtæršzæü in íhatwhe-efieân the firstcoolant circuit (23) comprises a first coolant branch (33), and wherein the first heat exchanger (27) is arranged in the first coolant branch (33). The powertrain (1) according to claim 5, the first coolantbranch (33) comprises a branch inlet (35) arranged upstream of the electric machine (9) and/or the power electronics (13). |25 10. 11. 1
2. 1
3. The powertrain (1) according to claim 5, charactæršznd in thatwhereân- the first coolantbranch (33) comprises a branch inlet (35) arranged downstream of the electric machine (9) and/or the power electronics (13). The powertrain (1) according to any one of the claims 2 - 7, cnaractnrizefi intjggggwner-ein the cooling system (23, 25) comprises a second coolant circuit (25)arranged to cool the battery (11), and wherein the powertrain (1) comprises a secondheat exchanger (29) arranged to exchange heat between the portion (21) of the engine coolant circuit (6) and the second coolant circuit (25). The powertrain (1) according to claim 8, characteršzed in thatæßlfàzflereieæ the secondcoolant circuit (25) comprises a second valve (37) arranged to regulate the flow of coolant through the second heat exchanger (29). The powertrain (1) according to claim 8 or 9, cnaracteršznzi in tnatwnerešn the secondheat exchanger (29) is arranged in a second coolant branch (39) of the second coolantcircuit (25), and wherein the second coolant branch (39) comprises an inlet (41) arranged upstream of the battery (11). The powertrain (1) according to any one of the preceding claims, characâefizeá intšïatwheifleias the portion (21) of the engine coolant circuit (6) is an engine coolant branch (45) of the engine coolant circuit (6). The powertrain (1) according to claim 11, characterized in thatwlaerein the enginecoolant circuit (6) comprises an engine radiator (46), and wherein the engine coolantbranch (45) comprises a branch inlet (47) arranged downstream of the engine radiator (46) and upstream of a coolant inlet (48) of the combustion engine (5). The powertrain (1) according to claim 12, the engine coolant circuit (6) comprises: - a radiator line (51) arranged to conduct coolant to the engine radiator (46), - a bypass line (53) arranged to conduct coolant past the engine radiator (46), - a first valve device (55) arranged to receive coolant from a coolant line (57) of theengine coolant circuit (6) and direct the coolant to the radiator line (51) and the bypass line (53), and 1
4. 1
5. 1
6. 1
7. 1
8. 1
9. 20. - a second valve device (61) arranged to receive coolant from the bypass line (53) and direct at least part of coolant flow from the bypass line (53) to the branch inlet (47). The powertrain (1) according to claim 13, the enginecoolant circuit (6) further comprises a radiator outlet line (59) arranged to conduct at least part of coolant flow from the engine radiator (46) to the branch inlet (47). The powertrain (1) according to any one of the claims 11 - 14, characteršzeä inÉggwiseæxain the engine coolant branch (45) comprises a third valve device (63) and abranch bypass line (65) connecting portions of the engine coolant branch (45), andwherein the third valve device (63) is controllable to a position in which flow of coolant isallowed through the branch bypass line (65) so as to form a separate coolant circuit through the branch bypass line (65) and the engine coolant branch (45). The powertrain (1) according to any one of the claims 11 - 15, charactæršzefi in tšfzatwherein the engine coolant branch (45) comprises a coolant pump (43). The powertrain (1) according to any one of the preceding claims, characterizecš år:thaiixfvheafein the engine coolant circuit (6) comprises an engine radiator (46), andwherein the cooling system (23, 25) comprises at least one radiator (70, 70', 74) arranged in front of the engine radiator (46). The powertrain (1) according to claim 17, characíerizeci in 'ihatwhereiaê the powertrain(1) comprises a charge air cooler (72) arranged between the at least one radiator (70,70', 74) and the engine radiator (46). The powertrain (1) according to any one of the claims 1-16, characteršzæd in that the engine coolant circuit (63 comprises an engine radiator (46), wherein the powertrain (1) comprises a charge air cooler (72), and wherein the cooling system (23, 25) comprisesat least one radiator (70, 70') between the charge air cooler (72) and the engine radiator (46) and at least one radiator (74) in front of the charge air cooler (72). The powertrain (1) according to claim 19 and any one of the claims 8 - 10, the at least one radiator (74) in front of the charge air cooler (72) is a radiator (74) of the second coolant circuit (25). 21. A vehicle (3) aharafzteršzeaš En that ïhe xfehicše (3) cfšengrises a powertrain (1) according to any one of the preceding claims.
SE1851575A 2018-12-14 2018-12-14 Hybrid Electric Powertrain, and Vehicle SE543213C2 (en)

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