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ELECTRIC & HYBRID VEHICLES, MICRO HEV: includes start-drop &…
ELECTRIC & HYBRID VEHICLES
History & Evolution
Early development and resurgence
Key milestones leading to modern EVs and HEVs
Type of vehicles
Battery Electric Vehicle (BEV)
Powered 100% by electric motor(s)
Zero tailpipe emissions
Energy from high-voltage battery pack
Charged from electrical grid
Examples: Tesla Model 3, Nissan Leaf, Audi e-tron
Hybrid Electric Vehicle (HEV)
key features: Internal Combustion Engine (ICE) & electric motor
4 TYPES
Mild Hybrid (MHEV)
: Electric motor assists the ICE. Cannot drive on electric power alone
Full Hybrid (FHEV)
: Can drive on electric power alone at low speeds. No plug-in charging
Plug-in Hybrid (PHEV)
: Larger battery than FHEV. Can be charged from the grid and drive significant distances on electric power
Key Components
Battery
: Stores and supplies electrical energy (Lithium-ion, Lithium Iron Phosphate, Nickel-Metal Hydride)
Electric Motor
: Converts electrical energy to mechanical energy to drive wheels (Permanent Magnet Synchronous Motor, Induction Motor, Switched Reluctance Motor)
Power Electronics
Inverter
: Converts DC to AC for motor, controls speed and torque
DC-DC Converter
: Steps down high voltage to low voltage for accessories
Bi-directional Converter
: Manages two-way power flow for charging/regeneration
Controllers
Battery Management System
: Monitors battery safety, temperature, cell balancing
Motor Control Unit
: Regulates motor operation based on driver input
Charging Unit
Manages external battery charging
Levels
: Level 1 (120V), Level 2 (240V), Level 3 (DC Fast Charging)
Protocols
: CCS, CHAdeMO, Tesla Supercharger
Working Principles & Key Features of HEVs
Engine Idle Stop-Start
: Switches off ICE when stationary to save fuel
Electric Torque Assistance
Torque Fill
: Compensates for engine torque delay
Torque Boost
: Adds to engine torque for maximum power (short duration)
Energy Recuperation (Regenerative Braking)
: Converts kinetic energy to electrical energy during braking to recharge the battery
Electric Driving
: Vehicle can be propelled by the electric motor alone (capability varies by HEV type)
Battery Charging
During driving
Charged by Internal Combustion Engine (ICE) or regenerative braking
Modes
Charge Deplete
: Battery fully charged and being used
Charge Sustain
: Battery maintained at minimum SOC by ICE
Charging
: Battery being actively charged
State of Charge (SOC)
: Minimum levels vary by HEV type (e.g., PHEV: 10-20%, Micro HEV: 80-90%)
From the Grid
Exclusive to Plug-in Hybrid Electric Vehicles (PHEVs)
Uses onboard rectifier to convert AC grid power to DC for battery charging
HEV Classification by Electric Motor Position (P0-P4)
P0
: Belt-driven motor on the engine front
P1
: Motor directly connected to the crankshaft
P2
: Motor located between the engine and transmission (decoupled)
P3
: Motor integrated within or located after the transmission
P4
: Motor on the rear axle, completely separate from the engine drivetrain
PS
: Power Split device (e.g., planetary gearset)
EE
: Separate electric axle
HEV Configurations & Architecture
Parallel Hybrid
One Clutch
: ICE and motor coupled; no pure electric drive
Two Clutches
: Engine can be disconnected; allows pure electric drive
Double-Clutch Transmission
: Motor connected to a transmission sub-unit
Axle-Split
: Motor and ICE on separate axles; enables all-wheel drive
Series Hybrid
ICE powers a generator, which charges the battery or powers the motor
No mechanical connection between ICE and wheels
Series-Parallel Hybrid
Combines series and parallel paths; uses a clutch to connect them
Power-Split Hybrid
Uses a planetary gear set to combine mechanical and electrical power paths
Engine speed is independent of vehicle speed
MICRO HEV
: includes start-drop & regenerative braking, no electric motor for proplusion