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The concept vehicle development project began in 1995, and by 2008, Kia Motor Company launched pilot production of hybrid vehicles for the Gets and Rio models. In 2009, the TD Spectra model with LPI technology and lithium polymer battery was launched as the world’s first LPI hybrid vehicle. Following the TD Spectra, the Optima Hybrid Electric Vehicle is going to be launched. The Optima HEV is a fulltype hybrid with electric drive mode. It boasts excellent fuel efficiency and power that stands shouldertoshoulder with the world’s leading hybrid vehicles.
Chapter Introduction of TF HEV(Hybrid Electric Vehicle) Preface Hybrid Electric Vehicle Optima Hybrid System Overview Optima Hybrid Control Mode Copyright ⓒ 2009~2010 All rights reserved No part of this material may be reproduced, stored in any retrieval system or transmitted in any form or by any means without the written permission of Kia Motors Corporation Chapter Introduction of TF HEV Preface Learning Objectives Describes overall summary about Hybrid Electric Vehicle (HEV) Details the definition of Hybrid Describes the Hybrid System categories The concept vehicle development project began in 1995, and by 2008, Kia Motor Company launched pilot production of hybrid vehicles for the Gets and Rio models In 2009, the TD Spectra model with LPI technology and lithium polymer battery was launched as the world’s first LPI hybrid vehicle Following the TD Spectra, the Optima Hybrid Electric Vehicle is going to be launched The Optima HEV is a full-type hybrid with electric drive mode It boasts excellent fuel efficiency and power that stands shoulder-to-shoulder with the world’s leading hybrid vehicles Chapter Introduction of TF HEV Hybrid Electric Vehicle 1.1 Why HEV? Atmospheric Pollution Strict Emission Gas Regulation CARB EURO Low Pollution Vehicle Ratio Regulation Environmentally Friendly Vehicles Global Warming Energy Crisis High Efficiency Power-train / Development of alternative energy New Concept Power-train - Electricity: Electric Vehicle, Fuel Cell Vehicle - Hybrid: HEV, Fuel Cell HEV Hybrid Electric Vehicle / Electric Vehicle / Fuel Cell Vehicle Global automotive companies are making significant investments in developing new concept automobiles that deliver high efficiency output with low emission This trend is in line with worldwide efforts to develop alternative energy in preparation for depleting petroleum resources, as well as to reduce CO2 emission with strict environmental pollution regulations that call for reduced NOx and measures against global warming The world faces depletion of fossil fuel energy resources in the 21 st Century, and with increasing concern about global warming, there is an urgent need to develop vehicles that have reduced carbon dioxide emission and conform to the emission control regulations pertaining to nitrogen oxide and hydrocarbon The state of California has forced major automobile manufacturers to produce a minimum of 2% of all vehicles as pollution-free automobiles Such strict regulation is anticipated to spread throughout America And the gasoline-powered vehicles is anticipated to fade into the history by 2030 Encouragingly, the market for hybrid vehicles is increasing and is forecast to account for 24% of the entire automobile market by 2010, a figure increasing to almost 50% by 2030 Such reality is causing the global automotive industry to focus on hybrid vehicles with dual power sources as the next generation of automobiles Developing hybrid vehicles is not an option but a necessity for automobile manufacturers to ensure a sustainable future with ever strengthening environmental regulations worldwide Chapter Introduction of TF HEV 1.2 What is HEV? Electric Motor / Battery Gasoline Engine / Diesel Engine + A Hybrid Electric Vehicle (HEV) is a vehicle driven by power sources (a combustion engine and high voltage battery) It is equipped with, and utilizes, a combination of a gasoline engine and electric motor, or a diesel engine and electric motor Usually, a combination of gasoline engine and electric motor is used In general, the term “Hybrid” means the combination of two different objects to create something new Therefore, the HEV can be defined as a vehicle that utilizes power from both the engine and the motor to achieve higher fuel efficiency - Power sources are used (Combustion engine + Electric motor) - Increased fuel economy - Reduced emission Memo Chapter Introduction of TF HEV 1.3 Types of HEV (by structure) Parallel type HEV System FMED (Flywheel Mounted Electric Device) TMED (Transmission Mounted Electric Device) Power split Not available : Mild (Soft) type Available : Full (Hard) type Available : Full (Hard) type EV mode Wheel Battery Wheel Engine Wheel Battery Schematic Engine TM Motor HSG Motor TM Clutch Wheel Battery Wheel Wheel S1 Wheel Engine Motor Clutch1 TM FD - Hyundai: Gets, Accent - Kia: Rio - Honda: Civic, Accord - Hyundai: Sonata - Kia: Optima - PSA: 308, C4 - VW: Touareg, - Audi: Q7 - Porsche: Cayenne MG1 C1 Engine Clutch Wheel Model Wheel FD Battery Clutch FD R1 CL1 MG2 S2 C2 CL2 BK1 FD R2 Wheel - Toyota: Prius, Camry, RX400h, Highlander - Ford: Escape, Mariner - GM: Tahoe, Yukon - Benz: ML450 Let’s learn about the common hybrid types They are the parallel-type and the power-split type Parallel-Type In the case of the parallel-type, the engine and drive shaft are mechanically connected so the system requires a transmission It has the benefit of accommodating a small capacity drive motor The paralleltype is categorized as the Flywheel Mounted Electric Device (FMED) type and the Transmission Mounted Electric Device (TMED) type depending on the mounting position of the motor In the case of the FMED type, the motor is mechanically connected to the engine and the system executes engine start, engine power assist and regenerative braking functions This type, however, makes it structurally impossible for electric drive mode It is also known as a mild or soft type hybrid system Vehicles using the FMED type include Honda Civic/Accord, Hyundai Accent/HD Elantra, and KIA Rio/Forte In contrast, the motor in the TMED type is directly connected to the transmission and is separated from the engine There is a clutch between the engine and the motor This separation allows electric drive mode As the TMED type allows electric drive mode, it has higher fuel efficiency than the FMED type A system that has electric drive mode capability is also known as a full or hard type hybrid system It uses existing transmission and investment cost is therefore lower However, it does require precision control Also, because the motor and engine are separated, the TMED type requires an additional starter to start the engine while the vehicle is in motion The TMED type is utilized in Kia Optima, Peugeot, Volks Wagon, Audi, and Porsche hybrid Power Split Type The power split type, which is also known as the Toyota Hybrid System (THS) (because it was first developed by Toyota), connects the engine and motors via planetary gear sets It uses planetary gears and motor control instead of transmission to control the vehicle speed As the power split type Chapter Introduction of TF HEV allows electric drive mode, it is a full type hybrid Although it has the drawback of requiring a highcapacity motor, it boasts efficiency and outstanding driving stability Toyota, Ford, GM, BMW, and Mercedes utilize the power split type in their hybrid vehicles 1.4 Comparison of Mild Type and Full Type Start Coasting Accelerate/Uphi ll Decelerate Stop Engine+Motor Engine Engine+Motor Inertia Energy Battery Charge Engine Auto Stop [Mild(Soft) type] Start Coasting (low-speed) Motor Coasting (high speed) Accelerate/ Uphill Motor+Engine Decelerate Stop Inertia Energy Battery Charge Engine Auto Stop [Full(Hard) type] The differentiating criteria of the mild type and the full type are whether the hybrid vehicle can drive with only electric motor power and without the need for the engine In the case of the mild type, which does not support electric drive mode, both the motor and the engine power are used during startup However the vehicle runs by the engine without motor assist when less loaded such as coasting driving In cases of acceleration or highly engine loaded such as in uphill driving, the motor supports the engine power When the vehicles brakes, the generated heat energy is transformed into electricity by the motor and stored in the battery This process is also known as regenerative braking When the vehicle comes to a stop, the engine is also stopped to conserve fuel This is known as idle stop In the case of the full type, the vehicle is driven only by the electric motor during startup and low speed Chapter Introduction of TF HEV 1.5 Plug-In Hybrid Electric Vehicle (PHEV) System Cat Stru ctur e Conventional Vehicle Hybrid Electric Vehicle Plug-In Hybrid Battery Battery Battery Engine Engine Gas Battery Electric Motor Electric Motor Engine Electric Vehicle Gas Gas Electric Motor Pow er Sou rce Engine Engine+Motor Engine+Motor Motor Fuel Gasoline Gasoline Electricity, Gasoline Electricity Hybrid vehicles are more widely used for their environmentally friendliness However, the engine on hybrid vehicles are not being used efficiently and a large amount of electric energy is lost during the conversion and storing process The PHEV, which many automobile manufacturers are recently turning to, eliminates energy loss during the energy conversion process and utilizes existing efficient engines The Plug-in Hybrid Vehicle is a hybrid vehicle with an added electric plug to charge the battery using general household electricity This represents a midpoint before complete migration to electric vehicles Compared to general hybrid vehicles, the Plug-in Hybrid has a longer battery and motor driving distance It is therefore highly efficient in terms of fuel consumption and emission gas This vehicle can travel approximately 30 miles on a single charge, and it uses regular diesel or gasoline fuel for farther distances Many major automobile makers forecast that the global hybrid vehicle market will grow to over 40 million vehicles annually by 2020, and most believe that the majority of these hybrids will be Plug-in Hybrid Vehicles Chapter Introduction of TF HEV Optima Hybrid System Overview 2.1 Hybrid System Components Theta-II 2.4 HEV - Atkinson Cycle HPCU (Hybrid Power Control Unit) - Integrated package : Motor/HSG Inverter (MCU), LDC, HCU High voltage battery - Lithium-polymer Electric motor : 30kW Hybrid cluster Electric A/C compressor Speed AT - Without torque converter - Engine clutch + Electric motor AHB (Active Hydraulic Booster) - Increased regenerative energy AAF (Active Air Flap) Electric oil pump HSG (Hybrid Starter Generator) - 8.5kW The main components of the Optima hybrid system are, · Theta-II 2.4 HEV · Speed Automatic Transaxle · Electric motor & HSG (Hybrid Starter Generator) · High voltage battery · MCU (Motor Control Unit, or Inverter) · LDC (Low DC-DC Converter) · HCU (HEV system Control Unit) Chapter Introduction of TF HEV 2.2 Hybrid Engine (Theta-II 2.4 MPI with Atkinson Cycle) Lower valve spring force Thermostat Atkinson Cycle Gas oline Hybri d Increase compression ratio Piston ring coating Chrome CrNPVD Theta-Ⅱ Atkinson cycle hybrid engine basically uses Theta II 2.4L MPI engine, but it is modified to maximize the engine efficiency and not the engine power for fuel economy In addition to the application of the Atkinson Cycle to reduce engine pumping loss, more items are utilized as below Compression ratio is increased and piston shape is changed to reduce the combustion chamber volume The thermostat opening temperature is increased to 88°C (190.4°F) resulting in better combustion Also, a lighter valve spring and a piston ring coated with low-friction material are used 10 Chapter Introduction of TF HEV 2.3 Hybrid Automatic Transaxle (A6MF2H) Case Gear Train Mechanical Oil Pump Engine Clutch TCU (PCU Type) Torsion Damper Valve Body Electric Oil Pump OPU Instead of CVT which is widely used in other competitors, the hybrid vehicle’s exclusive 6-speed automatic transaxle is installed to transfer power from the engine or motor The torque converter in existing automatic transaxle is removed Instead, the motor, engine clutch and torsional damper are installed in its place The electric oil pump is mounted on the side of the automatic transaxle It generates required hydraulic pressure for transaxle and engine clutch during low speed driving or Electric Vehicle mode in which the vehicle operates only on the motor with the engine stopped 11 Chapter Introduction of TF HEV 2.4 Electric Motor & HSG (Hybrid Starter Generator) Electric motor HSG (Hybrid Starter Generator) AT assembly Electric Motor The drive motor installed in the Optima Hybrid has achieved the highest performance in its class with a maximum power output of 30 kilo watt from the electric motor that produces a maximum torque of 205 Newton meter The hybrid electric motor is an important component that receives power from the battery and supports the engine power during acceleration It recharges the battery with the electric energy generated during deceleration In Electric Vehicle mode, the electric motor provides traction power necessary to move the vehicle without support from the engine In hybrid mode, the electric motor supports engine power and stores output energy during braking using the generator Hybrid Starter Generator (HSG) 12 Chapter Introduction of TF HEV The Hybrid Starter Generator or HSG assembly allows the Optima Hybrid to switch between Electric Vehicle and Hybrid modes It cranks the engine for starting and can acts as a generator when necessary if the hybrid battery state of charge is below a specified threshold 2.5 High Voltage Battery & BMS Cooling system High voltage battery Lithium-ion polymer battery 270V / 5.3Ah, 72Cells in series BMS* Voltage, Current, Temperature sensing SOC* estimation, Power-cut, Cooling control, Relay control, Cell balancing, Diagnosis Maintain proper temperature Equipped with BLDC* cooling pan - Increase air flow & Reduce noise Power Relay Ass’y(PRA) Relay ON/OFF control Battery current check The high-voltage battery has four major components contained in the assembly The 270 volt battery assembly is developed using the lithium-ion polymer battery technology To enhance safety, the assembly uses a battery current check circuit which shuts off electric current in case of over-charge A 12 volt blower air cooling system is used to maintain optimal battery temperature by passing cool air through the battery case The Battery Management System module is contained inside the battery case and maintains the optimal performance of the high voltage battery The BMS measures the current, voltage and temperature of the battery and estimates the high voltage battery stage of charge It controls the battery cooling fan to maintain optimal battery operation temperature and performs the cell balancing control which minimizes voltage deviation of each cell during battery charging and discharging In addition, if a system fault occurs, the BMS turns off the high-voltage relay to protect hybrid system from the high voltage In addition, active protection devices such as the power relay assembly and fuse are used to improve reliability and durability 13 Chapter Introduction of TF HEV 2.6 Motor Control Unit (MCU) or Inverter MCU = Inverter + Converter Inverting AC Motor DC MCU High voltage battery Converting HSG The MCU has an inverter feature that transforms direct current to alternating current, and at the same time a converter feature that does the reverse The MCU’s inverter circuits generates alternating current to operate the electric motor from the direct current of the high voltage battery The MCU’s converter circuits transforms the alternating current of the motor to Direct current to charge the high voltage battery - Inverter: Transforming the DC of High Voltage Battery to AC for Motor operation - Converter: Converting the generated AC to DC for High Voltage Battery Charging 14 Chapter Introduction of TF HEV Memo 2.7 Low voltage DC-DC converter (LDC) Hybrid Electric Vehicle Conventional Vehicle Alternator Batter y Electric load High voltage battery (270V) Inverter (MCU) LDC Aux Battery(12V) Electric load In conventional vehicles, an alternator is used to supply 12-volt power to electric devices and charge the battery while the engine is running But in Hybrid Electric Vehicle, the LDC transforms the electric power from the high-voltage battery to 12 V and supplies power to electric devices and the auxiliary battery Because the LDC is used, there is no alternator on the HEV and not additional engine load - Converting 270 DC voltage to 12V DC voltage - Charging the 12V auxiliary battery (Alternator is removed) 15 Chapter Introduction of TF HEV Memo 2.8 Active Air Flap (AAF) - Reduced air resistance according to the driving condition - Better fuel economy Input signals Flap open Chassis-CAN Flap close · Engine coolant temperature · A/C pressure · Outside temperature · Vehicle speed · Etc (LDC/Motor temp.) Smart Actuator An active air flap is mounted between the front bumper grille and the radiator It is controlled according to the driving conditions The flap is closed while driving to reduce air resistance When the engine temperature increases to the threshold, the flap is opened to reduce the engine room temperature The engine coolant temperature, A/C pressure, and the vehicle speed are transmitted via CAN communication and the smart actuator opens and closes the flap 16 Chapter Introduction of TF HEV 2.9 Hybrid Brake System Pedal travel sensor Hydraulic Braking Amount Master cylinder + Pedal simulator Regenerative Braking Amount (by Motor) ESC (HEV) AHB (Active Hydraulic Booster) Hydraulic flow Electronic flow Total Braking Amount (Cooperative Control) The brake vacuum booster which uses the engine vacuum cannot be used in an electric-motor-driven hybrid vehicle Therefore, an active hydraulic booster is used A pedal simulator and pedal travel sensor are also added and provide a pedal feeling for those drivers who are used to the vacuum booster During braking, the hydraulic brake and regenerative brake by the electric motor are engaged simultaneously 17 Chapter Introduction of TF HEV 2.10 Electric A/C Compressor Electric A/C Compressor FATC HCU ② ⑤ ③ ④ ① No Description A/C ON signal input Operating permission & Max power signal Permission & Allowable power Compressor RPM within allowable power Compressor RPM & power consumption An electric compressor is used to ensure continued operation of the A/C, even when the engine stops If the A/C switch is pressed, the FATC sends an operation authorization request to the HCU The HCU transmits the operation allowance signal with an allowable electric power amount to the FATC The FATC controls the electric compressor within the allowable electric power range 18 Chapter Introduction of TF HEV 2.11 Technology for Fuel Economy Normal Vehicle Hybrid Electric Vehicle Idle-stop EV, Assist Regeneration Braking Stand by Stand by Fuel Drive Drive Drive Braking LDC Operating pt Idle stop Reduced fuel loss LDC Reduced engine load Downsizing (Atkinson cycle) Regenerative braking Torque converter removed T / M Engine E T W Fuel Optimize engine operation point EV, Assist Better engine efficiency Energy recycling Improve driving efficiency Less air resistance 19 Chapter Introduction of TF HEV The main goal of developing the hybrid vehicle is to reduce emission gas and increase fuel efficiency In particular, technology that recycles or reduces energy loss during combustion is utilized to improve fuel efficiency Approximately 80% of energy is known to be lost in a gasoline engine Even when assuming complete combustion, most of the energy generated from the fuel in the combustion chamber undergoes numerous loss-incurring processes, and only a portion of the energy is used to drive the vehicle There are various types of energy loss Some of the major areas of loss include exhaust, cooling, engine pumping, operation of various engine support components, drive resistance, and brake loss In the case of hybrid vehicles, various technologies that either reduce or recycle such energy losses and their applications are listed as follows: - Engine torque and RPM control activate the engine in fuel-efficient conditions - Engine turn off when the vehicle comes to a stop (idle stop) to improve fuel efficiency - Power loss reduction caused by removing the generator due to the LDC - Atkinson Cycle application to reduce engine pumping loss - Brake loss conversion to electric energy to charge the high voltage battery - Torque converter elimination in automatic transmission to reduce power loss - Vehicle’s air resistance reduction to improve fuel efficiency 20 Chapter Introduction of TF HEV Optima Hybrid Control Mode 3.1 HEV System Control Mode Engine Cranking Engine HSG Motor AT EV Driving FD Clutch Engine HSG Engine Only Driving HSG AT FD Clutch Battery Battery Engine Motor Motor AT Clutch Battery HEV Driving ; Power Assist by Motor FD Engine HSG Motor AT FD Clutch Battery Engine Cranking The Hybrid Starter Generator (HSG) is activated with electricity from the high voltage battery The drive belt linked to the HSG is driven and the engine starts In the event of HSG failure or the drive belt broken, the engine is started by the electric motor EV Driving If the state of charge of the high voltage battery is normal, only the electric motor power is used when the vehicle starts to move or during low-speed driving As the engine is OFF, the automatic transmission hydraulic pressure is generated by the electric oil pump When the A/C is activated, the electricity is supplied to the electric A/C compressor from the high voltage battery Engine Only Driving This mode uses only engine power while driving The engine clutch is engaged to transfer engine power to the transmission HEV Driving: Power Assist by Motor In cases of sudden acceleration, the electric motor is activated to support the engine power and increase torque 21 Chapter Introduction of TF HEV HEV Driving ; Charging by Engine Engine Motor AT FD Clutch HSG Regenerative Braking Engine HSG Motor AT FD Clutch Idle Charging (Vehicle Stop in Drive & SOC Low) Motor AT Clutch HSG FD Battery Battery Engine AT Battery FD Idle Stop Engine HSG Motor Clutch Battery HEV Driving: Charging by Engine This control mode uses the motor as an alternator to charge the high voltage battery while driving with engine power This mode is engaged when the state of charge of the high voltage battery is low Regenerative Braking This control mode converts the kinetic energy of the vehicle, which is dissipated when the vehicle decelerates or comes to a stop, to electrical energy This electrical energy is then used to charge the high voltage battery The electric motor is used as an generator and the braking effect increases as the generation amount also increases The AC generated by the electric motor passes through the MCU and is converted to DC which is supplied to the high voltage battery Idle Charging When the state of charge of the high voltage battery is low, the engine runs idle when the vehicle comes to a stop to charge the battery The HSG, connected to the drive belt, is used as the generator after engine startup The generated AC passes through the MCU and is converted to DC which is supplied to the high voltage battery Idle Stop If the state of charge of the high voltage battery is normal, the engine turns off when the vehicle comes to a stop As the vehicle is powered only by the electric motor when it starts to move, the engine is not restarted 22 Chapter Introduction of TF HEV 3.2 Hybrid System Configuration ECM TCM PCM * Dual CAN: Hybrid CAN and Chassis CAN Many control devices are connected to the high-speed CAN in the Optima HEV The devices send and receive various kinds of system information If there is too much load on the CAN, the communicating data become unstable The Dual High Speed CAN (Hybrid CAN + Chassis CAN) is used to eliminate this problem The Dual CAN is applied to vehicle-drive-related systems including the HCU, ECM, TCM, MCU, and BMS Abbreviations · HPCU: Hybrid Power Control Unit · HCU: HEV Control Unit · PCM: Power-train Control Unit · ECM: Engine Control Unit · TCM: Transmission Control Unit · OPU: Oil pump Unit · MCU: Motor Control Unit · BMS: Battery Management System · LDC: Low Voltage DC-DC Converter · ESC: Electronic Stability Control · FATC: Full Automatic Temperature Control · MDPS: Motor Driven Power Steering · ACU: Airbag Control Unit · AHB: Active Hydraulic Booster · AAF: Active Air Flap · TPMS: Tire Pressure Monitoring System · EWP: Electronic Water Pump · VESS: Virtual Engine Sound System · TMU: Telematics Unit 23 ... Gets and Rio models In 2009, the TD Spectra model with LPI technology and lithium polymer battery was launched as the world’s first LPI hybrid vehicle Following the TD Spectra, the Optima Hybrid... - Honda: Civic, Accord - Hyundai: Sonata - Kia: Optima - PSA: 308, C4 - VW: Touareg, - Audi: Q7 - Porsche: Cayenne MG1 C1 Engine Clutch Wheel Model Wheel FD Battery Clutch FD R1 CL1 MG2 S2 C2... installed in the Optima Hybrid has achieved the highest performance in its class with a maximum power output of 30 kilo watt from the electric motor that produces a maximum torque of 205 Newton meter