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Electric and Hybrid Vehicles - Coggle Diagram
Electric and Hybrid Vehicles
Electric vehicle (EV)
Battery electric vehicles (BEVs)
Can be powered by:
collector system by electricity
from off-vehicle sources
self-contained with a
battery
solar panels
electric generator to convert fuel
to electricity
Relies soley on electric motors to power the wheels
The architecture is with an electric motor on one of the axles, a fixed step gearbox and a high voltage battery.
Main components
Battery
The battery is normally recharges from mains electricity via plugs and a bettery charging unit that can ether be carried on board or fitted at the charging point.
Electric motor
Transmission
Controller
The controller controls the power supplied to the motor and allows regenrative braking in forward and reverse directions
In BEV, without a range extender, the enegry for traction is supplied 100% from the high voltage battery.
Hybrid electric vehicles (HEVs)
liquid fuels in conjunction
with electricity
Sources of power:
Internal Combustion Engine (ICE)
Electric motor
Functions:
Engine idle stop-start
The stop - start (S&S) function
switches off the ICE, without the intervention of the driver when the vehicle is stationary.
Help reduce the overall fuel consumption of the vehicle.
Electric torque assistance (fill and boost)
Electric motor can provide additional torque to the wheel, improving the overall torque response of the powertrain, there are 2 types of torque assistance:
Torque fill
Torque boost
Functions of electric torque assistance is provided by:
Mild Hybrid Electric Vehicle (MHEV)
Full Hybrid Electric Vehicle
(FHEV)
Plug-in Hybrid Electric Vehicle (PHEV)
When both the engine and the electric motor are providing torque for vehicle acceleration, the vehicle is in hybrid/parallel mode.
Energy recuperation (regenerative braking)
The total required braking torque at the wheels can be achieved in several ways:
Only through the hydraulic brakes
Through the hydraulic brakes plus the powertrain
In vehicles with ICE only
The fuel injection is interrupted to achieve engine braking only when the brake pedal is pressed.
In a HEV
A negative torque can be requested from the electric motor, enhancing the braking capability of the power train when the brake pedal is pressed.
During vehicle braking, the electric motor is in generator mode in all HEVs.
The kinetic enegy of the vehicle spins the rotor of the generator, overcoming its negative torque and electrical energy is generated. Thus, the electrical energy generated is used to charge the battery.
• Electric driving
If the electric motor is powerful enough, the vehicle can be driven in electric mode.
Plug-in Hybrid Electric Vehicle (PHEV)
The high voltage battery has a higher capacity
Electric mode is possible up to speeds of 90 - 100 km/h
The ICE is switched off and the electric motor is providing all the necessary torque for the propulsion of the vehicle
Full Hybrid Electic Vehicle (FHEV)
Electric mode is only possible up to vehicles speeds of 5 - 10 km/h
It has limited enegry available in the battery
• Battery charging (during driving)
Every battery has a minimum state of charge (SOC) which needs to be maintained in order to avoid permanent damage.
State Of Charge (SOC)
It represent the theoretical amount of electrical enery avalible in the battery
If the minimum SOC for the battery is 20% we can only use 80% of the theoretical maximum.
Different modes of the battery
Charge deplete mode
Battery is fully charged and ready to be depleted
Charge sustain mode
Battery reaches minimum SOC and charged by ICE
Charging mode
Vehicle is braking and kinetic energy is converted to electrical energy to charge the battery
Battery charging (from the grid)
Battery being charged by a power socket
Power electronics control module of a plug in hybrid electric vehicle contaons a rectifier which converts the alternating current (AC) of the power socket into direct current (DC) and stored into the high voltage battery.
Plug in Hybrid Electric Vehicle (PHEV)
Key features:
Larger battery and longer electric range compared to full hybrids
Full Hybrid Electric Vehicle (FHEV)
Key features:
Larger batterty and more powerful motor than a mild hybrid (MHEV) but smaller then a PHEV
Can drive on electric power alone unlike MHEV which always need the engine and has regenrative braking to recharge the battery.
Does not require any plug in. Because the battery charges through the engine and regenrative braking
Mild Hybrid Electic Vehicle (MHEV)
Key features:
Small battery (48V or 12V system), it helps supposts the engine but doesnt provide full elecgtric drive.
electric motor assists the engine during acceleration and stop-start situations
regenerative braking recovers energy to recharge the battery
No need for external charging as the system recharges itself from using the engine and braking energy.
It cannot run on electric power alone but it uses a small electric motor to assist the internal combustion engine (ICE) for improved efficency and helps reduce emissions.
Micro Hybrid Electric Vehicle (Micro HEV)
Key features:
Start - stop system
Regenerative braking
No electric motor
NO external charging
Small battery (12V or 24V system)
Key components in HEV
Battery
Functions:
Stores and supplies electrical energy to power the EV/Hybrid.
Types:
Lithium-ion (Li-ion)
Most common due to the high energy density and longevity
Lithium Iron Phosphate
Commonly used in electric vehicle
Nickel metal Hydride (NiMH)
Used in hybrid vehicles
Key considerations
Capacity (kWh)
Voltage
Charging time
Lifespan
Thermal managment
Motor
Functions:
It converst electrical energy into mechanical energy to drive the wheels.
Types:
Permanent Magnet Synchronous Motor (PMSM): High efficiency, commonly used in EVs.
Induction Motor
Switched Reluctance Motor (SRM)
Efficiency and performance
Highly efficieny (90-95%)
Instant torque delivery
Regenerative braking to recover energy
Inverter
Functions:
Converts DC power from the battery into AC power for the electric motor
Key Features:
Controls motor speed and torque
Enhances energy efficiency by optimizing power conversion
Enables regenerative braking by converting AC power from the motor back to DC power for the battery
Battery Mnagement Controller
Functions:
Monitors and regulates battery performance to
ensure safety and efficiency
Key roles:
Voltage and temperature regulation to prevent overheating and overcharging
Overcharge and discharge protection to extend battery lifespan
Balancing individual cell performance for uniform aging and efficiency
Communication with the vehicle’s control unit for optimal energy usage
Fault detection and diagnostics for early issue identification
Control Unit
Regulates and controls the operation of the electric motor
Converts driver input (accelerator pedal position) into motor torque control
Monitors and optimizes motor performance for efficiency and power delivery
manages regenrative braking to recover energy
Protects against motor overheating and electrical faults
Charging Unit
Manages the charging of the EV battery from external sources.
Types:
Level 1 (120V AC): Slow charging using standard household outlets
Level 2 (240V AC): Faster charging with dedicated EV chargers
Level 3 (DC Fast Charging): High-power charging stations reducimg charging time to 30 minutes
Considerations
Charging infrastructure availabilty
Onboard chargers vs external DC fast chargers
Charging protocols (CCS, CHAdeMO, Tesla Supercharger, etc)
HEV configurations
Parallel
Parallel hybrid with one clutch
Layout for mild hybrid
Parallel hybrid with two clutch
Layout for strong hybrid
Parallel hybrid with double-clutch
transmission
Allow for both engine and motor to drive in parallel
Axle-split parallel hybrid
Motor and engine are completely separated. They are on each axle
Series
Series hybrid
Engine can be optimized to only operate in a set of range of rpm
Series-parallel hybrid
Extension of series hybrid layout with addition of clutch
Power Split
Combines the advantages of series and parallel layouts but at the expenses of increased mechanical complexity
Classification by electric motor positon
