HYBRID VEHICLE – DEFINITION • THE TERM HYBRID MEANS A BLEND OR MIX OF TWO DISSIMILAR TYPES INTERNAL COMBUSTION ENGINE…….. [ ICE ] ELECTRIC TRACTION MOTOR
Definitions • HEV = Hybrid Electric Vehicle • Incorporates an electric motor / generator and an ICE engine • BEV = Battery Electric Vehicle • Has an electric motor / generator and batteries . Does not have an ICE engine • H2EV = Hydrogen Fuel Cell Vehicle • Has an electric motor and a hydrogen fuel cell to generate electricity from electro-chemical reaction between hydrogen and oxygen
Definitions • H2ICE = Hydrogen Powered Internal Combustion Engine • A conventional ICE vehicle [diesel or spark ignition] that is fueled by hydrogen • PHEV = Plug in Hybrid Vehicle • A hybrid electric vehicle with additional batteries that are used to extend range and increase speed under electric operation and use energy from the electric power grid instead of gasoline.
ADVANTAGES OF HYBRID VEHICLES • INCREASED FUEL ECONOMY • Typically 20% to 30% better • PERFORMANCE IS IMPROVED • Especially at low speeds • RANGE & REFUELING TIME • Same as a conventional vehicle • DRIVEABILITY • Nearly identical to conventional vehicle
DISADVANTAGES OF HYBRID SYSTEMS • HIGHER COST • CURRENTLY HYBRID VEHICLES ARE PRICED TYPICALLY $3000 TO $6000 MORE THAN COMPARABLE CONVENTIONAL VEHICLES • SAFETY ISSUES • IN AN ACCIDENT RESCUE PERSONAL MUST BE AWARE OF THE PROPER PROCEDURES NEEDED TO EXTRACT ACCIDENT VICTIMS FROM THE VEHICLE • THE ENERGY POTENTIAL OF MOST HYBRID BATTERY SYSTEMS CAN ELECTROCUTE YOU IF YOUR BODY COMES INTO CONTACT WITH THE WIRING
Safety training • Rescue personnel need to be trained in the potential electrical hazards when extracting vehicle occupants after a crash
Parallel Hybrid Drive System • A Parallel Hybrid has a direct mechanical connection between the ICE engine and the wheels. ICE Engine PCM Battery Array Motor / Generator Inverter • Parallel Hybrids use a conventional transmission or an electro-mechanical torque splitting transmission that combines the power of the ice engine and electric motor[s] Transmission
Series Hybrid Drive System • A Series Hybrid is essentially a battery powered electric vehicle that has an auxiliary power unit to provide additional range • In a series Hybrid there is no mechanical connection between the ICE engine and the wheels ICE Engine Electric Motor PCM Battery Array Inverter Generator
Series Hybrid Drive System • A generator is bolted to the back of the engine to provide electric power to the motor after the battery SOC drops below minimum • The battery array is large enough to provide 40 miles of electric power – after 40 miles the ICE engine can provide power as long as there is gasoline in the tank • This type of vehicle is normally called an electric powered vehicle with a range extending gas engine Generator Electric Motor
Series Hybrid Generator • Chassis with Electric Motor and Generator Charging Socket Battery Array Traction Motor Image courtesy of General Motors Corp
Series Hybrid 3 Cylinder turbocharged ICE engine • With ICE engine and fuel tanks Inverter Fuel Tanks Image courtesy of General Motors Corp
Series Hybrid Electric Power Assist Brake Booster • With Cooling system, Steering and Brakes Radiator For ICE Engine Electric Power Steering Image courtesy of General Motors Corp
Hybrid efficiency Two technologies that make hybrids more efficient than conventional vehicles • Autostop • Regenerative Braking
Electric Torque Assist • Most hybrids also have electric torque assist. • When power is required both the ICE engine and the electric motor provide torque. • Electric torque assist allows the ICE engine to be smaller and still have adequate performance
Autostop • The ICE engine is shut down while vehicle is stationary • On some hybrids the system can shut off the ICE engine during coast, deceleration or driving at slower speeds under electric power • The ICE engine is restarted when the brake pedal is released or the gas pedal is depressed
Auto Stop Mode The ICE Engine is turned off as long as the driver holds pressure on the brake pedal and the vehicle not moving. Autostop When the driver releases the pedal the engine will restart. Some hybrids restart when the accelerator pedal is depressed.
Regenerative Braking • During normal braking the hybrid drive system slows the vehicle by converting the electric motor into a generator – recharging the batteries • Instead of loosing all the kinetic energy to heat in conventional brakes the kinetic energy is converted into electricity which can be stored and used again to accelerate and climb hills
Hybrid Types Light - Auto Stop and Regenerative Braking only Mild - Electric Traction assist – vehicle cannot run solely on electric power Full - Electric only operation at up to 30 MPH – engine shuts down on coast Plug In - batteries can be charged overnight by 110 or 220 volt household current. Vehicle can be driven 10 to 40 miles solely by electric power. Currently in the Prius Plug-in and Chevy Volt
Light Hybrid – Type 1 Stator Coils attached to Bell Housing • Motor/Generator built into bell housing. • Motor/Generator does not provide torque for power assist. • Conventional planetary gearset automatic transmission delivers torque to drive axels. • Electrically driven pump maintains pressure on transmission clutches and bands during auto stop. • Torque converter clutch is modified for 2 way torque transfer. • Transmission is calibrated to lock out freewheeling when brakes are applied. Permanent magnets attached to flex plate Electrically driven transmission pump
Light Hybrid – Type 1 • 42 Volt hybrid system – Lead Acid Batteries • Motor/Generator serves as starter and generator • Electrical current produced by motor/generator is used for restarting the engine after auto stop and operating electric power steering pump for PS and Hydro-boost brake assist • Auto stop mode will not activate when A/C is set to MAX or defroster is selected • Motor/Generator can provide 24 Kw at 110 volts to outlets in the truck bed • Used on GM PHT trucks • Saturn Vue Greenline is similar
Mild Hybrid – Type 2 Stator coils attached to rear of engine block Permanent magnets embedded in flywheel • Motor/Generator provides extra torque for acceleration Starting Clutch • Motor/Generator sandwiched between engine and bell housing • CVT [Continuously Variable] automatic transmission delivers torque to drive axel[s] • Starting clutch eliminates the need for a torque converter
Porsche Cayenne Hybrid Motor/Generator Stator coils attached to rear of engine block Permanent magnets embedded in flywheel Coolant Image courtesy of Robert Bosch GMBH
Mild Hybrid – Type 2 • Cannot run in electric only mode • High voltage hybrid system – 144 to 190 volts • Ni MH battery type • Motor / Generator develops 10 to 15 Kw [13 to 20 hp] • Motor / Generator is cooled by contact with engine block • Uses V-TEC technology for variable displacement and to reduce engine drag during regenerative braking
Full Hybrid – Type 3 Motor / Generator # 2 Motor / Generator # 1 • Runs in electric only mode at speeds below 25 mph depending on battery state of charge • High voltage hybrid system – 190 to 400+ volts • Uses a torque splitter planetary gearset type transmission.
Full Hybrid – Type 3 • Ni MH battery type • Motor / Generator develops 50 to 125 Kw [67 to 167 hp] • Motor / Generator must be liquid cooled. Antifreeze coolant or transmission fluid circulating through the transaxle removes excess heat • Atkinson cycle engine may be used for improved fuel economy • Uses VTT technology for Atkinson cycle operation and cylinder canceling to improve fuel economy at highway cruise speeds. • Since the vehicle can run on electric power alone, electric power steering and power brake assist are required • Air conditioning compressor will also be powered electrically
Full Hybrid transaxle • The motor/generators of a full hybrid are located inside the transaxle case • A full hybrid transaxle will normally have 2 large motor/generators inside the transaxle • A planetary gearset is used to combine the torque of the electric motor with that of the ICE engine
Plug in Hybrid – Type 4 • Batteries are charged overnight by 110 volt household current • Li – ion battery type • Battery capacity is 4 times greater than Full Hybrid Increased Battery Capacity • Can be driven solely by electric power at speeds up to 100 mph • Has an electric only range of 10 to 40 miles • When battery SOC drops below 30% ICE engine automatically starts
Plug-in Series Hybrid • The 2014 Chevy Volt has an electric range of over 40 miles • A series hybrid is essentially an electric car that has a backup gasoline engine to extend the range. Image courtesy of General Motors Corp
Plug-in Series Hybrid Range Extender Engine • 40 mile range under electric power • The engine will start when the batteries are depleted, allowing the vehicle to be driven another 360 miles before refueling Charging Receptacle Battery Pack Electric Motor
Full Hybrid vs. Plug In Hybrid • A full hybrid vehicle is primarily powered by an ICE engine. It’s electric vehicle technology enables it to recover energy normally wasted. • A plug In hybrid is primarily powered by electricity from the power grid, but has the extended range and refueling convenience of a conventional ICE vehicle when driven longer distances. • A plug in hybrid can run on any type of energy that can be used to generate electricity.
Hybrid Technology • Smaller – yet more powerful engine systems • Both motors; electric and ICE combine to produce the power needed for acceleration and climbing hills • A small displacement 75 Hp ICE motor combined with a 67 HP electric motor[s] will have the same power as a conventional vehicle with a larger 140 Hp motor.
Accessories • Since the ICE engine is shut down during autostop and at low speeds power accessories that are normally driven by belt and engine vacuum must be powered by electricity: • Power Brakes • Power Steering • Air Conditioning
Electric Power Brake Assist • An electrically driven pump mounted on the ABS brake actuator assembly produces the high hydraulic pressure needed to bring the vehicle to a stop without excessive brake pedal force • In normal braking the Hybrid Control Module turns on solenoids in the ABS actuator that block the flow of hydraulic pressure to the front brakes. This allows the regenerative braking system to recover the maximum available energy. Accumulator Pump
Electric Power Steering • Conventional hydraulic power steering uses up to 5 hp of engine power even when the need for steering assist is low. Steering Control Module Electric Motor Steering Torque Sensor
Electric Power Steering • The electric motor can be mounted on the rack or steering column. Steering input torque sensor Image courtesy of Robert Bosch GMBH
Electric A/C Compressor • To maintain comfortable cabin temperatures during Auto-stop mode an electrically driven A/C compressor is used. S D 200+ volt 3 phase AC Electric Motor
Electric A/C Compressor 200+ volt single phase AC Electric Motor • This GM electric compressor uses high voltage single phase AC current to drive the compressor motor. S D
Electric Heat • Electric heating strips are attached to the fins of the heater core. During Auto-stop or electric drive mode electric current is applied to the heating strips. Heater core Ribbon Fin Heating Strips Electrode
Low Drag Tires and Wheel Bearings • Tires used on high efficiency hybrid vehicles are designed for lower rolling resistance. Rolling resistance is reduced by: - Stiffer belts to reduce standing waves - More flexible sidewalls - Narrower tread width • Wheel bearings can be made of high silicon steel The higher silicon content can tolerate bearing lubricants with lower viscosity Improved seals are needed to retain this low viscosity lubricant
Improved Aerodynamics • Extending the slope of the front and rear ends of the body reduces turbulence and drag.
Improved Fuel Efficiency • Each of these technologies help improve vehicle fuel efficiency. • Combined in one vehicle they can add up to 40% increase in fuel efficiency. • No hybrid vehicle in production today has all of these technologies but some hybrids have most of them.