hybrid and plug-in hybrid vehicles

Upload: ankush-jain

Post on 08-Apr-2018

255 views

Category:

Documents


3 download

TRANSCRIPT

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    1/17

    Yogesh Maheshwari (07010029)Suryakanth Shabolu (07010041)

    Abhinay Jain (07D10031)

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    2/17

    y Ahybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle.The term most commonly refers to hybrid electric vehicles (HEVs), which combine an internalcombustion engine and one or more electric motors.

    y The hybrid vehicles have a wide scope in the upcoming future. The main reasons of it are- Regenerativebraking actually makes city driving more economical thanon the highway

    Fuel efficiency is greatly increased (twice).

    Emissions are greatly decreased

    Dependencyon fossils fuels can be decreased.

    Hybridscan be run on alternative fuels as well.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    3/17

    Regenerative Braking: When you take your foot offthe accelerator, the electric motor applies resistance to thedrive train, causing the wheels to slow down. The wheels turnthe motor now, (rather than the electric motor driving thewheels), which functions as a generator to produce electricityand charge the batteries.

    Electric Motor Drive/Assist: The electric motorprovides additional power to assist the engine in accelerating,passing, or hill climbing. Thus a smaller, lighter, more efficientengine can be used in the vehicle. In some vehicles, theelectric motor alone, provides power for low-speed driving.The internal combustion engines only start once a set speedhas been achieved.

    Automatic Start/Shutoff: This feature automaticallyshuts off the gasoline engine when the vehicle comes to a stop.It also restarts the gasoline engine when the accelerator ispressed. Thus, the vehicle never wastes gasoline from idling,and reduces the associated pollution.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    4/17

    Several of the current hybrid vehicles, vehicles like theFord Escape and the Toyota Prius, use Atkinson cycleengines in stead of the conventional Otto-cycle.

    The Atkinson-cycle engine is up to 10% more

    efficient than a conventional four-stroke petrol "Otto"engine. The increase in efficiency comes mainly fromcontrolling the so called pumping losses.

    Pumping losses are caused by the way poweroutput from a petrol "Otto" engine is regulated. Itis regulated by controlling, or rather constrictingairflow to the engine. This constriction of airflowcreates partial vacuum (low pressure) in the inletmanifold. Maintaining this "low pressure" in theinlet manifold wastes energy.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    5/17

    One reason for diesel "Otto"-enginesbeing more effective than thecorresponding petrol engines is becausethere is no pumping loss in a diesel aspower is regulated by injecting less

    fuel into the cylinders and not bychoking the airflow to the cylinders.

    The pumping losses in an Atkinsoncycle engine are reduced by allowing, inthe compression stroke, a small amount

    of the fuel/air mixture to flow backfrom the cylinder into the inductionsystem, without being burned, thusreducing the effective displacement ofthe engine.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    6/17

    The modern version of the Atkinson Cycle has four strokes and uses the samecrank design as the Otto Cycle. The difference is in how the valves are operated.

    During the intake stroke, the intake valve opens before the piston starts itsdownward travel, but instead of closing the valve as the compression stroke begins.

    The intake valve is held open even as the compression starts. The intake valvefinally closes very late in the compression stroke.

    This delayed closing of the valve allows air in the cylinder to be pushed back intothe engine intake manifold, so there is very little vacuum created in the manifold.

    This reduces engine pumping losses, or the restriction caused by a vacuum as thepiston goes through the intake stroke.

    The rest of the cycle continues with compression, power and exhaust the same asthe Otto Cycle design.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    7/17

    The Atkinson cycle Additionally as theexpansion ratio of an Atkinson cycle engine isgreater than its compression ratio it takesmore heat from the exhaust gas instead ofpumping it into the exhaust system, thereby

    achieving additional efficiency. also called the "five-stroke cycle" (becauseof the backflow which is really not a cycle) works like this: intake, backflow (partialexpulsion to eliminate pumping losses),compression, expansion, and exhaust.

    The combustion chamber volume is adapted tomaintain a constant compression ratio toavoid knock while increasing the expansionratio to optimize efficiency.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    8/17

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    9/17

    As the name implies, the High Efficiency Hybrid Cycle' (HEHC)attempts to combine the best features of numerous thermodynamiccycles including Otto, Diesel, Rankine, and Atkinson to create ahighly efficient engine.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    10/17

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    11/17

    Current HEVs reduce petroleum consumption under certaincircumstances, compared to otherwise similar conventional vehicles,primarily by using three mechanisms:

    1. Reducing wasted energy during idle/low output, generally by turningthe ICE off

    2. Recapturing waste energy (i.e. regenerative braking)3. Reducing the size and power of the ICE, and hence inefficiencies

    from under-utilization, by using the added power from the electricmotor to compensate for the loss in peak power output from the

    smaller ICE.

    Any combination of these three primary hybrid advantages may be usedin different vehicles to realize different fuel usage, power, emissions,weight and cost profiles.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    12/17

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    13/17

    The ICE in an HEV can be smaller, lighter, and more efficient than the onein a conventional vehicle, because the combustion engine can be sized forslightly aboveaverage power demand rather than peak power demand.

    The drive system in a vehicle is required to operate over a range of speedand power, but an ICE's highest efficiency is in a narrow range of operation,making conventional vehicles inefficient.

    On the contrary, in most HEV designs, the ICE operates closer to its rangeof highest efficiency more frequently.

    The power curve of electric motors is better suited to variable speeds andcan provide substantially greater torque at low speeds compared withinternal-combustion engines.

    The greater fuel economy of HEVs has implication for reduced petroleumconsumption and vehicle air pollution emissions worldwide.

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    14/17

    A Plug-in hybrid electric vehicle(PHEV or PHV), also known as a plug-inhybrid, is a hybrid vehicle withrechargeable batteries that can be restoredto full charge by connecting a plug to an

    external electric power source (usuallysimply a normal electric wall socket).

    A PHEV shares the characteristics of botha conventional hybrid electric vehicle,having an electric motor and an internal

    combustion engine; and of an all-electricvehicle, also having a plug to connect tothe electrical grid.

    Chevrolet Volt

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    15/17

    Battery Compartment of CalCars"PRIUS+"

    PHEVs typically require deeper batterycharging and discharging cycles thanconventional hybrids.Because the number of full cycles influencesbattery life, this may be less than in

    traditional HEVs which do not deplete theirbatteries as fully.However, some authors argue that PHEVswill soon become standard in the automobileindustry.Design issues and trade-offs against battery

    life, capacity, heat dissipation, weight, costs,and safety need to be solved. Advanced battery technology is underdevelopment, promising greater energydensities by both mass and volume, andbattery life expectancy is expected to increase

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    16/17

    Each kilowatt hour of battery capacity in use willdisplace up to 50 U.S. gallons (190 l; 42 imp gal) ofpetroleum fuels per year (gasoline or diesel fuels).Also, electricity is multi-sourced and, as a result,it gives the greatest degree of energy resilience.

    Claimed fuel economy for PHEVs depends on theamount of driving between recharges.If no gasoline is used the MPG equivalentdepends only on the efficiency of the electricsystem. A 120 km (70 mi) range PHEV-70 may annuallyrequire only about 25% as much gasoline as asimilarly designed PHEV-0, depending on how itwill be driven and the trips for which it will beused.The furthest all-electric range in a PHEV plannedfor mass production is the PHEV-60 BYD F6e.

    BYD F6e

  • 8/7/2019 Hybrid and plug-in hybrid vehicles

    17/17