Hybrid vehicle
Encyclopedia
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...
s (HEVs), which combine an internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
and one or more electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
s.
Power
Power sources for hybrid vehicles include:- On-board or out-board rechargeable energy storage system (RESS)
- Air engine|Compressed air
- Coal, wood or other solid combustibles
- Electricity
- Electromagnetic fields, Radio waves
- Compressed natural gas|Compressed or liquefied natural gas
- Human-powered vehicle|Human powered e.g. pedaling or rowing
- Hydrogen vehicle|Hydrogen
- Liquid nitrogen vehicle|Liquid nitrogen
- Petrol or Diesel fuel
- Solar vehicle|Solar
- sail boat|Wind
- Waste heatWaste heatWaste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...
from internal combustion engine.
Two-wheeled and cycle-type vehicles
MopedMoped
Mopeds are a type of low-powered motorcycle designed to provide economical and relatively safe transport with minimal licensing requirements.Mopeds were once all equipped with bicycle-like pedals , but moped has been increasingly applied by governments to vehicles without pedals, based on their...
s, electric bicycles, and even electric kick scooter
Electric kick scooter
An electric kick scooter is a small platform with two or more wheels that is propelled by an electric motor. Besides the motor, propulsion can also happen by the rider, pushing off to the ground.- Overview :...
s are a simple form of a hybrid, as power is delivered both via an internal combustion engine or electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
and the rider's muscles. Early prototypes of motorcycles in the late 19th century used the same principles.
- In a parallel hybrid bicycle human and motor power are mechanically coupled at the pedal drive train or at the rear or the front wheel, e.g. using a hub motor, a roller pressing onto a tire, or a connection to a wheel using a transmission element. Human and motor torques are added together. Almost all manufactured models are of this type. See Motorized bicycles, MopedMopedMopeds are a type of low-powered motorcycle designed to provide economical and relatively safe transport with minimal licensing requirements.Mopeds were once all equipped with bicycle-like pedals , but moped has been increasingly applied by governments to vehicles without pedals, based on their...
s and for more information.
- In a series hybrid bicycle (SH) the user powers a generator using the pedals. This is converted into electricity and can be fed directly to the motor giving a chainless bicycleChainless bicycleA chainless bicycle is a bicycle that transmits power to the driven wheel through a mechanism other than a metal chain.Examples:* Directly driven "ordinary" bicycle * Shaft-driven bicycle* Belt-driven bicycle...
but also to charge a battery. The motor draws power from the battery and must be able to deliver the full mechanical torque required because none is available from the pedals. SH bicycles are commercially available, because they are very simple in theory and manufacturing.
The first known prototype and publication of an SH bicycle is by Augustus Kinzel (US Patent 3'884'317) in 1975. In 1994 Bernie Macdonalds conceived the Electrilite SH lightweight vehicle which used power electronics allowing regenerative braking
Regenerative brake
A regenerative brake is an energy recovery mechanism which slows a vehicle or object down by converting its kinetic energy into another form, which can be either used immediately or stored until needed...
and pedaling while stationary. In 1995 Thomas Müller designed a "Fahrrad mit elektromagnetischem Antrieb" in his 1995 diploma thesis and built a functional vehicle. In 1996 Jürg Blatter and Andreas Fuchs of Berne University of Applied Sciences built an SH bicycle and in 1998 mounted the system onto a Leitra
Leitra
Leitra is a Danish company and also the name of the velomobile it makes. In Sweden a design for two persons called Fantom was sold as blueprints in the 1930s and 40s.Many thousands of DIY instructions were sold, but very few were actually built....
tricycle (European patent EP 1165188). In 1999 Harald Kutzke described his concept of the "active bicycle": the aim is to approach the ideal bicycle weighing nothing and having no drag by electronic compensation. Until 2005 Fuchs and colleagues built several prototype SH tricycle
Tricycle
A tricycle is a three-wheeled vehicle. While tricycles are often associated with the small three-wheeled vehicles used by pre-school-age children, they are also used by adults for a variety of purposes. In the United States and Canada, adult-sized tricycles are used primarily by older persons for...
s and quadricycles.
Heavy vehicles
Hybrid power trains use diesel-electric or turbo-electricTurbo-electric
A turbo-electric transmission uses electric generators to convert the mechanical energy of a turbine into electric energy and electric motors to convert it back into mechanical energy to power the driveshafts....
to power railway locomotives, buses, heavy goods vehicles, mobile hydraulic machinery
Hydraulic machinery
Hydraulic machines are machinery and tools that use liquid fluid power to do simple work. Heavy equipment is a common example.In this type of machine, hydraulic fluid is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders and which becomes pressurised according to...
, and ships. Typically some form of heat engine (usually diesel) drives an electric generator or hydraulic pump which powers one or more electric or hydraulic motors. There are advantages in distributing power through wires or pipes rather than mechanical elements especially when multiple drives—e.g. driven wheels or propellers—are required. There is power lost in the double conversion from typically diesel fuel to electricity to power an electric or hydraulic motor. With large vehicles the advantages often outweigh the disadvantages especially as the conversion losses typically decrease with size. With the exception of non nuclear submarines, presently there is no or relatively little secondary energy storage capacity on most heavy vehicles, e.g. auxiliary batteries and hydraulic accumulator
Hydraulic accumulator
A 'hydraulic accumulator' is an energy storage device. It is a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure by an external source. That external source can be a spring, a raised weight, or a compressed gas...
s—this is changing.
Rail transport
EuropeAn is the new Autorail à grande capacité
Autorail à Grande Capacité
The Autorail à Grande Capacité is a category of multiple unit trains built by the Canadian train manufacturer Bombardier at Crespin for the French rail operator SNCF...
(AGC or high-capacity railcar) built by the Canadian company Bombardier
Bombardier Transportation
Bombardier Transportation is the rail equipment division of the Canadian firm, Bombardier Inc. Bombardier Transportation is one of the world's largest companies in the rail-equipment manufacturing and servicing industry. Its headquarters are in Berlin, Germany....
for service in France. This has dual mode (diesel and electric motors) and dual voltage capabilities (1500 and 25000 V) allowing it to be used on many different rail systems. The locomotive has been on trials in Rotterdam, the Netherlands with Railfeeding, a Genesse and Wyoming company.
China
The First Hybrid Evaluating prototype locomotive was designed and contracted by rail research center MATRAI
Matrai
MATRAI is the sum of abbreviations of RAI and MAT and means Iran Railway Research Centerprofile:The Railway Research Center is research department of Iranian Railways....
in 1999 and the sample was ready in 2000.
it was a G12 locomotive that was converted to hybrid by using a 200KW diesel generator and batteries and also was equipped with 4 AC traction motors (out of 4) retrofited in the cover of the DC traction motors.
Japan
The first operational prototype of a hybrid train engine with significant energy storage and energy regeneration capability was introduced in Japan as the KiHa E200
KiHa E200
The is a single-car hybrid diesel multiple unit operated by East Japan Railway Company on the Koumi Line. Three cars were delivered in April 2007, and introduced on 31 July 2007....
. It utilizes battery packs of lithium ion batteries mounted on the roof to store recovered energy.
North America
In the U.S., General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
introduced a prototype railroad engine with their "Ecomagination" technology in 2007. They store energy in a large set of sodium nickel chloride (Na-NiCl2) batteries to capture and store energy normally dissipated during dynamic braking
Dynamic braking
Dynamic braking is the use of the electric traction motors of a railroad vehicle as generators when slowing the Locomotive. It is termed rheostatic if the generated electrical power is dissipated as heat in brake grid resistors, and regenerative if the power is returned to the supply line...
or coasting downhill. They expect at least a 10% reduction in fuel use with this system and are now spending about $2 billion/yr on hybrid research.
Variants of the typical diesel electric locomotive include the Green Goat (GG) and Green Kid (GK) switching/yard engines
Switcher
A switcher or shunter is a small railroad locomotive intended not for moving trains over long distances but rather for assembling trains ready for a road locomotive to take over, disassembling a train that has been...
built by Canada's Railpower Technologies
RailPower Technologies
Railpower Technologies Corp. is a subsidiary of R.J. Corman Railroad Group that builds environmentally friendly hybrid and genset yard locomotives, founded by Frank Donnelly and Gerard Koldyk...
. They utilize a large set of heavy duty long life (~10 yr) rechargeable lead acid (Pba) batteries and 1000 to 2000 HP electric motors as the primary motive sources and a new clean burning diesel generator (~160 Hp) for recharging the batteries that is used only as needed. No power or fuel are wasted for idling—typically 60–85% of the time for these type locomotives. It is unclear if dynamic braking
Dynamic braking
Dynamic braking is the use of the electric traction motors of a railroad vehicle as generators when slowing the Locomotive. It is termed rheostatic if the generated electrical power is dissipated as heat in brake grid resistors, and regenerative if the power is returned to the supply line...
(regenerative) power is recaptured for reuse; but in principle it should be easily utilized.
Since these engines typical need extra weight for traction purposes anyway the battery pack's weight is a negligible penalty. In addition the diesel generator and battery package are normally built on an existing "retired" "yard" locomotive's frame for significant additional cost savings. The existing motors and running gear are all rebuilt and reused. Diesel fuel savings of 40–60% and up to 80% pollution reductions are claimed over that of a "typical" older switching/yard engine. The same advantages that existing hybrid cars have for use with frequent starts and stops and idle periods apply to typical switching yard use. "Green Goat" locomotives have been purchased by Canadian Pacific Railway
Canadian Pacific Railway
The Canadian Pacific Railway , formerly also known as CP Rail between 1968 and 1996, is a historic Canadian Class I railway founded in 1881 and now operated by Canadian Pacific Railway Limited, which began operations as legal owner in a corporate restructuring in 2001...
, BNSF Railway
BNSF Railway
The BNSF Railway is a wholly owned subsidiary of Berkshire Hathaway Inc., and is headquartered in Fort Worth, Texas. It is one of seven North American Class I railroads and the second largest freight railroad network in North America, second only to the Union Pacific Railroad, its primary...
, Kansas City Southern Railway
Kansas City Southern Railway
The Kansas City Southern Railway , owned by Kansas City Southern Industries, is the smallest and second-oldest Class I railroad company still in operation. KCS was founded in 1887 and is currently operating in a region consisting of ten central U.S. states...
and Union Pacific Railroad
Union Pacific Railroad
The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....
among others.
Cranes
Railpower Technologies Corp. engineers working with TSI Terminal Systems Inc. in Vancouver, British Columbia are testing a hybrid diesel electric power unit with battery storage for use in Rubber Tyred GantryRubber Tyred Gantry
A Rubber Tyred Gantry crane is a mobile gantry crane used for stacking intermodal containers within the stacking areas of a container terminal...
(RTG) cranes. RTG cranes are typically used for loading and unloading shipping containers onto trains or trucks in ports and container storage yards. The energy used to lift the containers can be partially regained when they are lowered. Diesel fuel and emission reductions of 50–70% are predicted by Railpower engineers. First systems are expected to be operational in 2007.
Road transport, commercial vehicles
FedEx
FedEx Corporation , originally known as FDX Corporation, is a logistics services company, based in the United States with headquarters in Memphis, Tennessee...
and others are starting to invest in hybrid delivery type vehicles—particularly for city use where hybrid technology may pay off first.
Military off-road vehicles
Since 1985, the U.S. military has been testing serial hybrid Humvees and have found them to deliver faster acceleration, a stealthStealth technology
Stealth technology also termed LO technology is a sub-discipline of military tactics and passive electronic countermeasures, which cover a range of techniques used with personnel, aircraft, ships, submarines, and missiles, to make them less visible to radar, infrared, sonar and other detection...
mode with low thermal signature
Infrared homing
Infrared homing refers to a passive missile guidance system which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track and follow it. Missiles which use infrared seeking are often referred to as "heat-seekers", since infrared is just below the...
/ near silent operation, and greater fuel economy.
Ships
Ships with both mast-mounted sailSail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
s and steam engine
Steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...
s were an early form of hybrid vehicle. Another example is the diesel-electric submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
. This runs on batteries when submerged and the batteries can be re-charged by the diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
when the craft is on the surface.
Newer hybrid ship-propulsion schemes include large towing kites
Power kite
A power kite or traction kite is a large kite designed to provide significant pull to the user.They come in three main forms: foils, leading edge inflatables and supported leading edge. There are also rigid-framed kites and soft single skin kites. There are several different control systems used...
manufactured by companies such as SkySails
SkySails
SkySails GmbH & Co. KG is a Hamburg-based company that sells equipment to propel cargo ships, large yachts and fishing vessels by the use of wind energy. The company was founded in 2001 by engineers Stephan Wrage and Thomas Meyer...
. Towing kites can fly at heights several times higher than the tallest ship masts, capturing stronger and steadier winds.
Aircraft
Taxiing and other ground operations of Boeing 737NGs will soon be done using hybrid electric drives as WheelTugWheelTug
WheelTug is a fully integrated ground propulsion system for aircraft which puts a high torque electric motor into the hub of the nose wheel to allow for backwards movement without the use of pushback tugs and to allow for forward movement without using the aircraft's engines. WheelTug will drive...
ground propulsion systems become available. By using the APU
Auxiliary power unit
An auxiliary power unit is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft, as well as some large land vehicles.-Function:...
(powered by a turbine) to energize a Chorus electric motor mounted in the landing gear for ground movement, aircraft will be operating in a hybrid configuration where the main engines are used only for take off, landing, and flight.
Boeing 737-800
Boeing 737
The Boeing 737 is a short- to medium-range, twin-engine narrow-body jet airliner. Originally developed as a shorter, lower-cost twin-engine airliner derived from Boeing's 707 and 727, the 737 has developed into a family of nine passenger models with a capacity of 85 to 215 passengers...
The Boeing Fuel Cell Demonstrator Airplane has a Proton Exchange Membrane (PEM) fuel cell/lithium-ion battery hybrid system to power an electric motor, which is coupled to a conventional propeller. The fuel cell provides all power for the cruise phase
of flight. During takeoff and climb, the flight segment that requires the most power, the system draws on lightweight lithium-ion batteries.
The demonstrator aircraft is a Dimona motor glider, built by Diamond Aircraft Industries of Austria, which also carried out structural modifications to the aircraft. With a wing span of 16.3 meters (53.5 feet), the airplane will be able to cruise at approximately 100 kilometers per hour (62 miles per hour) on power from the fuel cell.
Hybrid electric-petroleum vehicles
When the term hybrid vehicle is used, it most often refers to a Hybrid electric vehicle
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...
. These encompass such vehicles as the Saturn Vue
Saturn VUE
The Saturn Vue is a compact crossover SUV that was sold by General Motors' Saturn marque, and at one time was Saturn's best-selling model. It was the first vehicle to use the GM Theta platform when it was introduced in 2002. A second generation model was launched in 2007 for the 2008 model as a...
, Toyota Prius
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...
, Toyota Camry Hybrid, Ford Escape Hybrid, Toyota Highlander Hybrid, Honda Insight
Honda Insight
The Honda Insight is a hybrid electric vehicle manufactured by Honda and the first production vehicle to feature Honda's Integrated Motor Assist system. The first-generation Insight was produced from 1999 to 2006 as a three-door hatchback...
, Honda Civic Hybrid
Honda Civic Hybrid
The Civic hybrid, based on the seventh generation Civic, was first introduced to the Japanese market in December 2001. Honda claimed it was the most fuel efficient 5-passenger gasoline-powered production vehicle in the world at the time. It was introduced to the U.S. in spring 2002 as a 2003 model...
Lexus RX 400h and 450h and others. A petroleum-electric hybrid most commonly uses internal combustion engines (generally gasoline or Diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
s, powered by a variety of fuels) and electric batteries to power the vehicle. There are many types of petroleum-electric hybrid drivetrains, from Full hybrid to Mild hybrid
Mild Hybrid
Mild hybrids are essentially conventional fossil-fuel vehicles equipped with a large electric machine allowing the engine to be turned off whenever the car is coasting, braking, or stopped, yet restart quickly...
, which offer varying advantages and disadvantages.
Henri Pieper
Pieper
Pieper was a carmaker in Belgium.In 1900, Henri Pieper of Germany introduced a hybrid vehicle with an electric motor/generator, batteries, and a small gasoline engine. It used the electric motor to charge its batteries at cruise speed and used both motors to accelerate or climb a hill...
in 1899 developed the first gasoline-electric hybrid
Hybrid vehicle drivetrain
Hybrid vehicles are vehicles with two or more power sources in the drivetrain. There are many different types of hybrid vehicles, although only the gasoline-electric hybrid is currently commercially available....
automobile in the world. In 1900, Ferdinand Porsche
Ferdinand Porsche
Ferdinand Porsche was an Austrian automotive engineer and honorary Doctor of Engineering. He is best known for creating the first hybrid vehicle , the Volkswagen Beetle, and the Mercedes-Benz SS/SSK, as well as the first of many Porsche automobiles...
developed a series-hybrid using two motor-in-wheel-hub arrangements
Wheel hub motor
The wheel hub motor is an electric motor that is incorporated into a hub of a wheel and drives it directly.-Uses in current and future vehicles:...
with a combustion generator set providing the electric power, setting two speed records.
While liquid fuel/electric hybrids date back to the late 19th century, the braking regenerative hybrid was invented by David Arthurs, an electrical engineer from Springdale, Arkansas in 1978–79. His home-converted Opel GT was reported to return as much as 75MPG with plans still sold to this original design, and the "Mother Earth News" modified version on their website.
The plug-in-electric-vehicle (PEV) is becoming more and more common. It has the range needed in locations where there are wide gaps with no services. The batteries can be plugged in to house (mains) electricity for charging, as well being charged while the engine is running.
Continuously outboard recharged electric vehicle (COREV)
Given suitable infrastructure, permissions and vehicles, BEVBattery electric vehicle
A battery electric vehicle, or BEV, is a type of electric vehicle that uses chemical energy stored in rechargeable battery packs. BEVs use electric motors and motor controllers instead of, or in addition to, internal combustion engines for propulsion.A battery-only electric vehicle or...
s can be recharged while the user drives. The BEV establishes contact with an electrified rail, plate or overhead wires on the highway via an attached conducting wheel or other similar mechanism (see Conduit current collection
Conduit current collection
Conduit current collection is a system of electric current collection used by electric trams, where the power supply is carried in a channel under the roadway, rather than located overhead.-Description:...
). The BEV's batteries are recharged by this process—on the highway—and can then be used normally on other roads until the battery is discharged.
This provides the advantage, in principle, of virtually unrestricted highway range as long as you stay where you have BEV infrastructure access. Since many destinations are within 100 km of a major highway, this may reduce the need for expensive battery systems. Unfortunately private use of the existing electrical system is nearly universally prohibited.
The technology for such electrical infrastructure is old and, outside of some cities, is not widely distributed (see Conduit current collection
Conduit current collection
Conduit current collection is a system of electric current collection used by electric trams, where the power supply is carried in a channel under the roadway, rather than located overhead.-Description:...
, trams, electric rail, trolleys
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...
, third rail
Third rail
A third rail is a method of providing electric power to a railway train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost...
). Updating the required electrical and infrastructure costs can be funded, in principle, by toll revenue, gasoline or other taxes.
Hybrid fuel (dual mode)
Ground propulsion
Ground propulsion is a different term than transport, because it refers to solid bodies being propelled. Those bodies may be mounted on vats or using wheels while the latter dominates for standard applications....
, some also consider vehicles that use distinct energy sources or input types ("fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
s") using the same engine to be hybrids, although to avoid confusion with hybrids as described above and to use correctly the terms, these are perhaps more correctly described as dual mode vehicles:
- Some electric trolleybuses can switch between an on board diesel engineDiesel engineA diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
and overhead electrical power depending on conditions (see dual mode bus). In principle, this could be combined with a battery subsystem to create a true plug-in hybrid trolleybus, although , no such design seems to have been announced. - Flexible-fuel vehicleFlexible-fuel vehicleA flexible-fuel vehicle or dual-fuel vehicle is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank...
s can use a mixture of input fuels mixed in one tank — typically gasolineGasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
and ethanolEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, or methanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
, or biobutanol. - Bi-fuel vehicleBi-fuel vehicleBi-fuel vehicles are vehicles with multifuel engines capable of running on two fuels. On internal combustion engines one fuel is gasoline or diesel, and the other is an alternate fuel such as natural gas , LPG, or hydrogen...
:Liquified petroleum gasLiquified petroleum gasLiquefied petroleum gas is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer...
and natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
are very different from petroleum or diesel and cannot be used in the same tanks, so it would be impossible to build an (LPG or NG) flexible fuel system. Instead vehicles are built with two, parallel, fuel systems feeding one engine. While the duplicated tanks cost space in some applications, the increased range and flexibility where (LPG or NG) infrastructure is incomplete may be a significant incentive to purchase. - Some vehicles have been modified to use another fuel source if it is available, such as cars modified to run on autogas (LPG)AutogasAutogas is the common name for liquefied petroleum gas when it is used as a fuel in internal combustion engines in vehicles as well as in stationary applications such as generators. It is a mixture of propane and butane....
and diesels modified to run on waste vegetable oil that has not been processed into biodiesel. - Power-assist mechanisms for bicycleBicycleA bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....
s and other human-powered vehiclesHuman-powered transportHuman-powered transport is the transport of person and/or goods using human muscle power. Like animal-powered transport, human-powered transport has existed since time immemorial in the form of walking, running and swimming...
are also included (see Motorized bicycleMotorized bicycleA motorized bicycle, motorbike, cyclemotor, or vélomoteur is a bicycle with an attached motor and transmission used either to power the vehicle unassisted, or to assist with pedaling. Since it always retains both pedals and a discrete connected drive for rider-powered propulsion, the motorized...
).
Fluid power hybrid
HydraulicHydraulic hybrid
Hydraulic Hybrid Vehicles or HHVs are vehicles that use pressurized fluid, instead of electric power, as an additional or alternative power source along with an engine.- Principle of Operation :...
and pneumatic hybrid vehicles use an engine to charge a pressure accumulator to drive the wheels via hydraulic or pneumatic (i.e. compressed air) drive units. The energy recovery rate is higher and therefore the system is more efficient than battery charged hybrids, demonstrating a 60% to 70% increase in energy economy in EPA testing. Under tests done by the EPA, a hydraulic hybrid Ford Expedition
Ford Expedition
The Ford Expedition is a full-size SUV built by the Ford Motor Company. Introduced in 1997 as a replacement to the Ford Bronco, it was previously slotted between the smaller Ford Explorer and the larger Ford Excursion, but as of the 2005 model year, it is Ford's largest and last truck-based,...
returned 32 mpgus City, and 22 mpgus highway. UPS
United Parcel Service
United Parcel Service, Inc. , typically referred to by the acronym UPS, is a package delivery company. Headquartered in Sandy Springs, Georgia, United States, UPS delivers more than 15 million packages a day to 6.1 million customers in more than 220 countries and territories around the...
currently has two trucks in service with this technology.
While the system has faster and more efficient charge/discharge cycling and is cheaper than gas-electric hybrids, the accumulator size dictates total energy storage capacity and requires more space than a battery.
Electric-human power hybrid vehicle
Another form of hybrid vehicle are human power-electric vehicles. These include such vehicles as the Sinclair C5Sinclair C5
The Sinclair Research C5 is a battery electric vehicle invented by Sir Clive Sinclair and launched by Sinclair Research in the United Kingdom on 10 January 1985. The vehicle is a battery-assisted tricycle steered by a handlebar beneath the driver's knees. Powered operation is possible making it...
, Twike
TWIKE
The TWIKE is a human-electric hybrid vehicle /light electric vehicle designed to carry two passengers and cargo. It can be driven in electric-only mode or electric + pedal power mode .Constructed of lightweight materials such as aluminium and plastic, this...
, electric bicycle
Electric bicycle
An electric bicycle, also known as an e-bike, is a bicycle with an electric motor used to power the vehicle. Electric bicycles typically cost between and , use rechargeable batteries and can travel up to...
s, and electric skateboard
Electric skateboard
An electric skateboard is typically a modified skateboard propelled by an electric engine, the thrust of which is usually controlled with an RF remote. As with a regular skateboard, it is steered by the rider shifting his or her weight. It was originally designed for local transport, but with the...
s.
Parallel hybrid
The first mass production parallel hybrid is the Honda Insight
Honda Insight
The Honda Insight is a hybrid electric vehicle manufactured by Honda and the first production vehicle to feature Honda's Integrated Motor Assist system. The first-generation Insight was produced from 1999 to 2006 as a three-door hatchback...
.
Mild parallel hybrid
These types use a generally compact electric motor (usually <20 kW) to provide auto-stop/start features and to provide extra power assist during the acceleration, and to generate on the deceleration phase (aka regenerative braking).On-road examples include Honda Civic Hybrid
Honda Civic Hybrid
The Civic hybrid, based on the seventh generation Civic, was first introduced to the Japanese market in December 2001. Honda claimed it was the most fuel efficient 5-passenger gasoline-powered production vehicle in the world at the time. It was introduced to the U.S. in spring 2002 as a 2003 model...
, Honda Insight
Honda Insight
The Honda Insight is a hybrid electric vehicle manufactured by Honda and the first production vehicle to feature Honda's Integrated Motor Assist system. The first-generation Insight was produced from 1999 to 2006 as a three-door hatchback...
, Honda CR-Z
Honda CR-Z
The Honda CR-Z is a compact hybrid electric automobile manufactured by Honda and marketed as a "sport hybrid coupe." The CR-Z combines a hybrid gasoline-electric powertrain with traditional sports car elements...
, Honda Accord Hybrid, Mercedes Benz S400 BlueHYBRID, BMW 7-Series hybrids, General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...
BAS Hybrids and Smart fortwo
Smart Fortwo
The Smart Fortwo is a rear-engined two-seater city car manufactured by Smart GmbH, introduced at the 1998 Paris Motor Show as the Smart City Coupé, and currently in its second generation...
with micro hybrid drive.
Power-split or series-parallel hybrid
Typical passenger car installations include the Toyota PriusToyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...
, the Ford Escape, Ford Fusion, the Lexus RX400h, RX450h, GS450h, LS600h and CT200h.
In a power-split hybrid electric drive train there are two motors: an electric motor and an internal combustion engine. The power from these two motors can be shared to drive the wheels via a power splitter, which is a simple planetary gear
Epicyclic gearing
Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, or sun gear. Typically, the planet gears are mounted on a movable arm or carrier which itself may rotate relative to the sun gear...
set. The ratio can be from 0-100% for the combustion engine, or 0-100% for the electric motor, or an anything in between, such as 40% for the electric motor and 60% for the combustion engine. The electric motor can act as a generator charging the batteries.
On the open road, the primary power source is the internal combustion engine, when maximum power is required, for example to overtake, the electric motor is used to assist maximizing the available power for a short period, giving the effect of having a larger engine than actually installed. In most applications, the engine is switched off when the car is stationary reducing curbside emissions.
Series hybrid
Series-hybrid vehicles are driven by the electric motor with no mechanical connection to the engine. Instead there is an engine tuned for running a generator when the battery pack energy supply isn't sufficient for demands.
This arrangement is not new, being common in diesel-electric
Diesel-electric
Diesel-electric transmission or diesel-electric powertrain is used by a number of vehicle and ship types for providing locomotion.A diesel-electric transmission system includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors...
locomotive
Locomotive
A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...
s and ships. Ferdinand Porsche
Ferdinand Porsche
Ferdinand Porsche was an Austrian automotive engineer and honorary Doctor of Engineering. He is best known for creating the first hybrid vehicle , the Volkswagen Beetle, and the Mercedes-Benz SS/SSK, as well as the first of many Porsche automobiles...
used this setup in the early 20th century in racing cars, effectively inventing the series-hybrid arrangement. Porsche named the arrangement "System Mixt". A wheel hub motor
Wheel hub motor
The wheel hub motor is an electric motor that is incorporated into a hub of a wheel and drives it directly.-Uses in current and future vehicles:...
arrangement, with a motor in each of the two front wheels was used, setting speed records. This arrangement was sometimes referred to as an electric transmission, as the electric generator and driving motor replaced a mechanical transmission. The vehicle could not move unless the internal combustion engine was running.
The setup has never proved to be suitable for production cars, however it is currently being revisited by several manufacturers.
In 1997 Toyota released the first series-hybrid bus sold in Japan. Meanwhile, GM
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...
will introduce the Chevy Volt EREV in 2010, aiming for an all-electric range of 40 miles, and a price tag of around $40,000. Supercapacitors combined with a lithium ion battery bank have been used by AFS Trinity
AFS Trinity
AFS Trinity Power Corporation is an American corporation headquartered in Medina, WA with an engineering center in Livermore, CA that develops technology for plug-in hybrid electric vehicles. The company has developed PHEV technology that actively combines batteries with ultracapacitors...
in a converted Saturn Vue SUV vehicle. Using supercapacitors they claim up to 150 mpg in a series-hybrid arrangement.
Plug-in hybrid electric vehicle (PHEV)
Another subtype added to the hybrid market is the Plug-in Hybrid Electric Vehicle (PHEV). The PHEV is usually a general fuel-electric (parallel or serial) hybrid with increased energy storage capacity (usually Li-ion batteries). It may be connected to mains electricity supply at the end of the journey to avoid charging using the on-board internal combustion engine.This concept is attractive to those seeking to minimize on-road emissions by avoiding – or at least minimizing – the use of ICE during daily driving. As with pure electric vehicles, the total emissions saving, for example in CO2 terms, is dependent upon the energy source of the electricity generating company.
For some users, this type of vehicle may also be financially attractive so long as the electrical energy being used is cheaper than the petrol/diesel that they would have otherwise used. Current tax systems in many European countries use mineral oil taxation as a major income source. This is generally not the case for electricity, which is taxed uniformly for the domestic customer, however that person uses it. Some electricity suppliers also offer price benefits for off-peak night users, which may further increase the attractiveness of the plug-in option for commuters and urban motorists.
Fuel cell, electric hybrid
The fuel cell hybrid is generally an electric vehicle equipped with a fuel cellFuel cell
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
. The fuel cell as well as the electric battery are both power sources, making the vehicle a hybrid. Fuel cells use hydrogen as a fuel and power the electric battery when it is depleted. The Chevrolet Equinox
Chevrolet Equinox
The second generation Equinox was announced by GM on December 21, 2008, and debuted at the 2009 North American International Auto Show in Detroit. The 2010 Equinox went on sale in June 2009. It is built on a stiffened version of the same "Theta" platform used in the previous model. The new Equinox...
FCEV, Ford Edge Hyseries Drive and Honda FCX
Honda FCX
The Honda FCX Clarity is a hydrogen fuel cell automobile manufactured by Honda. The design is based on the 2006 Honda FCX Concept. The FCX Clarity demonstrates electric car qualities such as zero emissions while offering 5 minute refueling times and long range in a full function large sedan...
are examples of a fuel cell/electric hybrid.
Road safety for cyclists, pedestrians
A 2009 National Highway Traffic Safety Administration report examined HEV accidents that involved pedestrians and cyclists and compared them to accidents involving combustion-engine vehicles. The findings showed that, in certain road situations, HEVs are more dangerous for those on foot or bicycle. For accidents where a vehicle was slowing or stopping, backing up, entering or leaving a parking space (when the sound difference between HEVs and CEVs is most pronounced), HEVs were twice as likely to be involved in a pedestrian crash than CEVs. For crashes involving cyclists or pedestrians, there was a higher incident rate for HEVs than CEVs when a vehicle was turning a corner. But there was no statistically significant difference between the types of vehicles when they were driving straight.Environmental issues
Fuel consumption and emissions reductionsThe hybrid vehicle typically achieves greater fuel economy and lower emissions than conventional internal combustion engine vehicles (ICEVs), resulting in fewer emissions being generated. These savings are primarily achieved by three elements of a typical hybrid design:
- relying on both the engine and the electric motors for peak power needs, resulting in a smaller engine sized more for average usage rather than peak power usage. A smaller engine can have less internal losses and lower weight.
- having significant battery storage capacity to store and reuse recaptured energy, especially in stop-and-go traffic,which is represented by the city driving cycleDriving cycleA driving cycle is a series of data points representing the speed of a vehicle versus time.Driving cycles are produced by different countries and organizations to assess the performance of vehicles in various ways, as for example fuel consumption and polluting emissions.Fuel consumption and...
. - recapturing significant amounts of energy during braking that are normally wasted as heat. This regenerative braking reduces vehicle speed by converting some of its kinetic energy into electricity, depending upon the power rating of the motor/generator;
Other techniques that are not necessarily 'hybrid' features, but that are frequently found on hybrid vehicles include:
- shutting down the engine during traffic stops or while coasting or during other idle periods;
- improving aerodynamicsAutomotive aerodynamicsAutomotive aerodynamics is the study of the aerodynamics of road vehicles. The main concerns of automotive aerodynamics are reducing drag , reducing wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high speeds...
; (part of the reason that SUVs get such bad fuel economy is the drag on the car. A box shaped car or truck has to exert more force to move through the air causing more stress on the engine making it work harder). Improving the shape and aerodynamics of a car is a good way to help better the fuel economy and also improve handling at the same time. - using low rolling resistance tires (tires were often made to give a quiet, smooth ride, high grip, etc., but efficiency was a lower priority). Tires cause mechanical drag, once again making the engine work harder, consuming more fuel. Hybrid cars may use special tires that are more inflated than regular tires and stiffer or by choice of carcass structure and rubber compound have lower rolling resistance while retaining acceptable grip, and so improving fuel economy whatever the power source.
- powering the a/c, power steering, and other auxiliary pumps electrically as and when needed ; this reduces mechanical losses when compared with driving them continuously with traditional engine belts.
These features make a hybrid vehicle particularly efficient for city traffic where there are frequent stops, coasting and idling periods. In addition noise emissions
Roadway noise
Roadway noise is the collective sound energy emanating from motor vehicles. In the USA it contributes more to environmental noise exposure than any other noise source, and is constituted chiefly of engine, tire, aerodynamic and braking elements...
are reduced, particularly at idling and low operating speeds, in comparison to conventional engine vehicles. For continuous high speed highway use these features are much less useful in reducing emissions.
Hybrid vehicle emissions
Hybrid vehicle emissions today are getting close to or even lower than the recommended level set by the EPA (Environmental Protection Agency). The recommended levels they suggest for a typical passenger vehicle should be equated to 5.5 metric tons of carbon dioxide. The three most popular hybrid vehicles, Honda CivicHonda Civic
The Honda Civic is a line of subcompact and subsequently compact cars made and manufactured by Honda. The Civic, along with the Accord and Prelude, comprised Honda's vehicles sold in North America until the 1990s, when the model lineup was expanded...
, Honda Insight
Honda Insight
The Honda Insight is a hybrid electric vehicle manufactured by Honda and the first production vehicle to feature Honda's Integrated Motor Assist system. The first-generation Insight was produced from 1999 to 2006 as a three-door hatchback...
and Toyota Prius
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...
, set the standards even higher by producing 4.1, 3.5, and 3.5 tons showing a major improvement in carbon dioxide emissions.
Hybrid vehicles can reduce air emissions of smog-forming pollutants by up to 90% and cut carbon dioxide emissions in half.
Environmental impact of hybrid car battery
Though hybrid cars consume less petroleum than conventional cars, there is still an issue regarding the environmental damage of the hybrid car battery. Today most hybrid car batteries are one of two types: (1) nickel metal hydride, or (2) lithium ion; both are regarded as more environmentally friendly than lead-based batteries which constitute the bulk of gasoline car starter batteries today. There are many types of batteries. Some are far more toxic than others. Lithium ion is the least toxic of the three mentioned above.The toxicity levels and environmental impact of nickel metal hydride batteries—the type currently used in hybrids—are much lower than batteries like lead acid or nickel cadmium. However, nickel-based batteries are known carcinogens, and have been shown to cause a variety of teratogenic effects.
The Lithium-ion battery has attracted attention due to its potential for use in hybrid electric vehicles. Hitachi is a leader in its development. In addition to its smaller size and lighter weight, lithium-ion batteries deliver performance that helps to protect the environment with features such as improved charge efficiency without memory effect.
The lithium-ion batteries are appealing because they have the highest energy density of any rechargeable batteries and can produce a voltage more than three times that of nickel–metal hydride battery cell while simultaneously storing large quantities of electricity as well. The batteries also produce higher output (boosting vehicle power), higher efficiency (avoiding wasteful use of electricity), and provides excellent durability, compared with the life of the battery being roughly equivalent to the life of the vehicle.
Additionally, use of lithium-ion batteries reduces the overall weight of the vehicle and also achieves improved fuel economy of 30% better than gasoline-powered vehicles with a consequent reduction in CO2 emissions helping to prevent global warming.
Raw materials increasing costs
There is an impending increase in the costs of many rare materials used in the manufacture of hybrid cars. For example, the rare earth elementRare earth element
As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...
dysprosium
Dysprosium
Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime...
is required to fabricate many of the advanced electric motors and battery systems in hybrid propulsion systems. Neodymium
Neodymium
Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite...
is another rare earth metal which is a crucial ingredient in high-strength magnets that are found in permanent magnet electric motors.
Nearly all the rare earth elements in the world come from China, and many analysts believe that an overall increase in Chinese electronics manufacturing will consume this entire supply by 2012. In addition, export quotas on Chinese rare earth elements have resulted in an unknown amount of supply.
A few non-Chinese sources such as the advanced Hoidas Lake
Hoidas Lake
Hoidas Lake is a remote northern Canadian lake which lies approximately 50 kilometers north of Uranium City, Saskatchewan. Named in honor of Irvin Frank Hoidas, a Royal Canadian Air Force pilot officer killed in action during the Second World War when his Stirling W-7520 crashed near the Belgian...
project in northern Canada as well as Mount Weld
Mount Weld
Mount Weld is a mountain and a mine site in Western Australia, located about 30 km south of Laverton and 120 km east of Leonora. It ranks as one of the richest major rare earth deposits in the world....
in Australia are currently under development; however, the barriers to entry are high and require years to go online.
Alternative green vehicles
Other types of green vehicles include other vehicles that go fully or partly on alternative energy sources than fossil fuelFossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
. Another option is to use alternative fuel composition (i.e. biofuel
Biofuel
Biofuel is a type of fuel whose energy is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases...
s) in conventional fossil fuel-based vehicles, making them go partly on renewable energy sources.
Other approaches include personal rapid transit
Personal rapid transit
Personal rapid transit , also called podcar, is a public transportation mode featuring small automated vehicles operating on a network of specially built guide ways...
, a public transport
Public transport
Public transport is a shared passenger transportation service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement.Public transport modes include buses, trolleybuses, trams...
ation concept that offers automated on-demand non-stop transportation, on a network of specially built guideways.
Adoption rate
While the adoption rate for hybrids is small today (under 3% of new car sales in the U.S. for August 2010), it has to potential to be very large over time as more models are offered and incremental costs decline due to learning and scale benefits. However, forecasts vary widely. For instance, Bob Lutz, a long-time skeptic of hybrids, indicated he expects hybrids "will never comprise more than 10% of the U.S. auto market." Other sources also expect hybrid penetration rates in the U.S. will remain under 10% for many years.More optimistic views include predictions that hybrids would dominate new car sales in the U.S. and elsewhere over the next 10 to 20 years. Another approach examines the penetration rates (or S-curves) of four analogs (historical and current) to hybrid and electrical vehicles in an attempt to gauge how quickly the vehicle stock could be hybridized and/or electrified in the United States. The analogs are (1) the electric motors in U.S. factories in the early 20th century, (2) diesel electric locomotives on U.S. railways in the 1920-1945 period, (3) a range of new automotive features/technologies introduced in the U.S. over the past fifty years, and 4) e-bike purchases in China over the past few years. These analogs collectively suggest it would take at least 30 years for hybrid and electric vehicles to capture 80% of the U.S. passenger vehicle stock.
Hybrid buses
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Hybrid locomotive A hybrid train is a locomotive, railcar or train that uses an onboard rechargeable energy storage system , placed between the power source and the traction transmission system connected to the wheels.... Hybrid trucks
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External links
Hybrid Automobile Manufacturers' Websites- GM Hybrid Technology
- Lexus Hybrid Cars
- Toyota Hybrid Technology
- Ford Hybrid Car Technology
- Honda Hybrid Technology Site
- Hyundai Hybrid Technology
Other Hybrid Links
- Hybridization of Diesel powertrain in passenger cars
- Green Car Info - Hype and Hybrids
- Hybrids are now a smart buy on cost alone
- Hybrids a wise choice, constantly improving
- Side by side comprising between Best Fuel-efficient and High-performance Diesel and Hybrid SUV (2009–2010)
- Hino Hybrid Australia
- Hybrid Taxi Pilot Program
- Air-Powered Cars Could Challenge EV's in Cities
- Scuderi Group to Present Preliminary Results on Air-Hybrid Study and Update on Scuderi Engine Prototype Testing at Washington Auto Show
- Air-Powered Cars Could Challenge EV's In Cities