Petroleum electric hybrid vehicle

A Petroleum Electric Hybrid Vehicle (PEHV) is a vehicle using an on-board rechargeable energy storage system (RESS) and a fueled power source for vehicle propulsion. The different propulsion power systems may have common subsystems or components. The HV provides better fuel economy than a conventional vehicle because the engine is smaller and may be run at speeds providing more efficiency. Other techniques may be used to recover or reduce waste energy (such as regenerative braking and shutting down the combustion engine).

The term hybrid when used in relation with cars also has other uses. Prior to its modern meaning of hybrid propulsion, the word hybrid was used in the United States to mean a vehicle of mixed national origin; generally, a European car fitted with American mechanical components. This meaning has fallen out of use. In the import scene, hybrid was often used to describe an engine swap. Some have also referred to flexible-fuel vehicles as hybrids because they can use a mixture of different fuels — typically gasoline and ethanol alcohol fuel.

Technology
PEHVs most commonly use internal combustion engines and electric batteries to power electric motors. Modern mass-produced hybrids prolong the charge on their batteries by capturing kinetic energy via regenerative braking. Many PEHVs shut down the combustion engine at idle, and re-start the combustion engine when needed. As well, when cruising or in other situations where just light thrust is needed, "full" hybrids can use the combustion engine to generate electricity by spinning an electrical generator (often a second electric motor ) to either recharge the battery or directly feed power to an electric motor that drives the vehicle. This contrasts with all-electric cars which use batteries charged by an external source such as the grid, or a range extending trailer. Nearly all hybrids still require gasoline or diesel as their sole fuel source though other fuels such as ethanol or plant based oils have also seen occasional use.

In 2007, several manufacturers have announced that future vehicles will use aspects of hybrid technology to reduce fuel consumption without the use of electric motors (the hybrid drivetrain) to drive the vehicle. Regenerative braking can be used to recapture energy and stored to power electrical accessories, such as air conditioning. Shutting down the engine at idle can also be used to reduce fuel consumption and reduce emissions without the addition of a hybrid drivetrain. In both cases, some of the advantages of hybrid technology are gained while additional cost and weight may be limited to the addition of larger batteries and starter motors. There is no standard terminology for such vehicles, although they may be termed mild hybrids.

History
In 1898 Ferdinand Porsche designed the Lohner-Porsche carriage, a series-hybrid vehicle that broke several Austrian speed records, and also won the Exelberg Rally in 1901 with Porsche himself driving. Over 300 of the Lohner-Porsche carriages were sold to the public. As a series-hybrid, a gasoline engine powers a generator, which powered electric wheel motors. A large and heavy battery pack acted as an intermediate load-leveling device.

The 1915 Dual Power made by the Woods Motor Vehicle electric car maker had a four cylinder internal combustion engine and an electric motor. Below 15 mph (25 km/h) the electric motor alone drove the vehicle, drawing power from a battery pack, and above this speed the "main" engine cut in to take the car up to its 35 mph (55 km/h) top speed. About 600 were made up to 1918.

There have also been air engine hybrids where a small petrol engine powered a compressor. Several types of air engines also increased the range between fill-ups with up to 60% by absorbing ambient heat from its surroundings.

In 1959 the development of the first transistor-based electric car—the Henney Kilowatt—heralded the development of the electronic speed control that paved the way for modern hybrid electric cars. The Henney Kilowatt was the first modern production electric vehicle and was developed by a cooperative effort between National Union Electric Company, Henney Coachworks, Renault, and the Eureka Williams Company. Although sales of the Kilowatt were dismal, the development of the Kilowatt served was a historical "who's who" of electric propulsion technology.

A more recent working prototype of the electric-hybrid vehicle was built by Victor Wouk (one of the scientists involved with the Henney Kilowatt and also brother of author Herman Wouk ). Wouk's work with electric hybrid vehicles in the 1960s and 1970s earned him the title as the "Godfather of the Hybrid" ). Wouk installed a prototype electric-hybrid drivetrain into a 1972 Buick Skylark provided by GM for the 1970 Federal Clean Car Incentive Program, but the program was killed by the EPA in 1976 while Eric Stork, the head of the EPA at the time, was accused of a prejudicial coverup . Since then, hobbyists have continued to build hybrids but none was put into mass production by a major manufacturer until the waning years of the twentieth century.

The regenerative-braking hybrid, the core design concept of most production hybrids, was developed by Electrical Engineer David Arthurs around 1978 using off-the shelf components and an Opel GT. However the voltage controller to link the batteries, motor (a jet-engine starter motor), and DC generator was Mr. Arthurs'. The vehicle exhibited ~75 mpg fuel efficiency and plans for it (as well as somewhat updated versions) are still available through the Mother Earth News web site. The Mother Earth News' own 1980 version claimed nearly 84 mpg.

The Bill Clinton administration initiated the Partnership for a New Generation of Vehicles (PNGV) program on September 29 1993 that involved Chrysler, Ford, General Motors, USCAR, the DoE, and other various governmental agencies to engineer the next efficient and clean vehicle. The NRC cited automakers’ moves to produce hybrid electric vehicles as evidence that technologies developed under PNGV were being rapidly adopted on production lines, as called for under Goal 2. Based on information received from automakers, NRC reviewers questioned whether the “Big Three” would be able to move from the concept phase to cost effective, pre-production prototype vehicles by 2004, as set out in Goal 3.

The program was replaced by the hydrogen focused FreedomCAR initiative of George W. Bush's administration in 2001. The focus of the FreedomCAR initiative being to fund research too high risk for the private sector to engage in with the long term goal of developing emission / petroleum free vehicles.

In the intervening period, the widest use of hybrid technology was actually in diesel-electric locomotives. It is also used in diesel-electric submarines, which operate in essentially the same manner as hybrid electric cars. However, in this case the goal was to allow operation underwater without consuming large amounts of oxygen, rather than economizing on fuel. Since then, many submarines have moved to nuclear power, which can operate underwater indefinitely, though a number of nations continue to rely on diesel-electric fleets.

Automotive hybrid technology became successful in the 1990s when the Honda Insight and Toyota Prius became available. These vehicles have a direct linkage from the internal combustion engine to the driven wheels, so the engine can provide acceleration power. The 2000s saw development of plug-in hybrid electric vehicles (PHEVs), which can be recharged from the electrical power grid and do not require conventional fuel for short trips. The Renault Kangoo was the first production model of this design, released in France in 2003. However, the environmental benefits of plug-in hybrids depend somewhat on the source of the electrical power. In particular, electricity generated with wind would be cleaner than electricity generated with coal, the most polluting source. On the other hand, electricity generated with coal in a central power plant is still much cleaner than pure gasoline propulsion, due to the much greater efficiencies of a central plant. Furthermore, coal is only one source of centrally generated power, and in some places such as California is only a minor contributor, overshadowed by natural gas and other cleaner sources.

The Prius has been in high demand since its introduction. Newer designs have more conventional appearance and are less expensive, often appearing and performing identically to their non-hybrid counterparts while delivering 50% better fuel efficiency. The Honda Civic Hybrid appears identical to the non-hybrid version, for instance, but delivers about 50 US mpg (4.7 L/100 km) output, while increasing energy efficiency and reducing emissions. The Honda Insight, while not matching the demand of the Prius, is still being produced and has a devoted base of owners. Honda has also released a hybrid version of the Accord.

2005 saw the first hybrid sport utility vehicle (SUV) released, Ford Motor Company's Ford Escape Hybrid. Toyota and Ford entered into a licensing agreement in March 2004 allowing Ford to use 20 patents from Toyota related to hybrid technology, although Ford's engine was independently designed and built. In exchange for the hybrid licenses, Ford licensed patents involving their European diesel engines to Toyota. Toyota announced model year 2005 hybrid versions of the Toyota Highlander and Lexus RX 400h with 4WD-i which uses a rear electric motor to power the rear wheels negating the need for a differential. Toyota also plans to add hybrid drivetrains to every model it sells in the coming decade.

For 2007 Lexus offers a hybrid version of their GS sport sedan dubbed the GS450h with "well in excess of 300hp". The 2007 Camry Hybrid becomes available starting Summer 2006 in USA and Canada. The initial batch of Camry Hybrids are built in Japan; starting October 2006, Toyota Motor Manufacturing, Kentucky (TMMK) will also produce these hybrids. Also, Nissan announced the release of the Altima hybrid (technology supplied by Toyota) around 2007.

An R.L. Polk survey of 2003 model year cars showed that hybrid car registrations in the United States rose to 43,435 cars, a 25.8% increase from 2002 numbers. California, the nation's most populous state at one-eighth of the total population, had the most hybrid cars registered: 11,425. The proportionally high number may be partially due to the state's higher gasoline prices and stricter emissions rules, which hybrids generally have little trouble passing.

Honda, which offers Insight, Civic and Accord hybrids, sold 26,773 hybrids in the first 11 months of 2004. Toyota has sold a cumulative 306,862 hybrids between 1997 and November 2004, and Honda has sold a total of 81,867 hybrids between 1999 and November 2004.

Automobiles and light trucks
A number of manufacturers currently produce hybrid automobiles and light trucks, including Ford, General Motors, Honda, Mazda, Nissan, Peugeot, Renault and Toyota. For a list, see List of hybrid vehicles.

Microhybrids are small hybrid cars (see city car).

Combined sales of hybrids in the US rose 54% in February 2007 to more than 22,792 22,998 units, up 52% from the results in February 2006. The figures do not include sales of GM hybrids, which the automaker does not yet break out, but do reflect the addition of the Nissan Altima Hybrid, now sold in eight states.

See chart of recent sales of hybrid vehicles, compiled Feb 2007 :



Buses
In the United Kingdom, a local manufacturer has introduced a development of the London 'Double-Decker', a new interpretation of the traditional Red buses that are a feature of the extreme traffic density in London. These buses use a small diesel engine with electric storage through a lithium ion battery pack. The use of a 1.9 litre diesel instead of the typical 7.0 litre engine in a traditional bus demonstrates the possible advantages of serial hybrids in extremely traffic-dense environments.

The use of a battery pack allows a much smaller installed IC-power output, because the smaller power unit better reflects the average power requirement in a city environment. The batterypack and relatively high power electric motors provide the required power peaks for acceleration, and the high installed power of the motors is reflected by a high potental for brake-energy recovery.

This characteristic offers many potential advantages for Bus services: The smaller engine helps compensate for the additional package space and weight requirements of an energy store (here the lithium ion batteries). The solely electric drive to the axles avoids the need for complex gearboxes and regulatory software & its development that parallel hybrids such as Prius and co. require. The high electric installed power allows for an equivalently high energy recovery. (Automotive hybrids that use small electric motors parallel to IC engines can only recover a small proprtion of the available kinetic energy. The remainder is lost as heat in the service brakes as with a conventional non hybrid vehicle).

Based on a London test cycle, a reduction in CO2 emissions of 31% and fuel savings in the range of 40% have been demonstrated, compared with a modern 'Euro-4' compliant bus.Wrightbus

These savings make the use of similar hybrid concepts in urban environments increasingly likely and attractive to users such as refuse collection, delivery & courier services. The scale of the possible saving is such that even lead-acid energy storage is viable, depending on the target of the customer. Here, the final choice of system depends on the required compromise of available space in the vehicle; passenger density, purchase price, route mix, for example urban extra-urban mix; and of course legislative framework. Are emissions being taxed (CO2 minimised, NOx etc.)? Or is fuel heavily taxed (Europe vs. USA)? Here different technical solutions may be favoured according to the local legislation. (See also separate entries)

Also in 2005 GE introduced its hybrid shifters on the market. Toyota claims to have started with the Coaster Hybrid Bus in 1997 on the Japanese market. In May 2003 GM started to tour with hybrid buses developed together with Allison. Several hundreds of those buses have entered into daily operation in the US. The Blue Ribbon City Hybrid bus was presented by Hino, a Toyota affiliate, in January 2005.

New Flyer and Gillig produce hybrid buses using either ISE Corporation ThunderVolt or Allison's electric drive system. The Whispering Wheel bus is another hybrid.

Trucks
In 2003 GM introduced a diesel hybrid military (light) truck, equipped with a diesel electric and a fuel cell auxiliary power unit. Hybrid light trucks were introduced 2004 by Mercedes (Hybrid Sprinter) and Micro-Vett SPA (Daily Bimodale). International Truck and Engine Corp. and Eaton Corp. have been selected to manufacture diesel-electric hybrid trucks for a US pilot program serving the utility industry in 2004. In mid 2005 Isuzu introduced the Elf Diesel Hybrid Truck on the Japanese Market. They claim that approximately 300 vehicles, mostly route buses are using Hinos HIMR (Hybrid Inverter Controlled Motor & Retarder) system.

A promising but as-yet unseen application for hybrid vehicle technology would be in garbage trucks, since these vehicles do stop-start driving and often stand idling.

Petroleum electric hybrid truck makers: DAF Trucks, MAN AG with MAN TGL Series, Nissan Motors, Renault Puncher with Renault Puncher.

Hybrid technology: ZF Friedrichshafen.

Military vehicles
The United States Army's manned ground vehicles of the Future Combat System all use a hybrid electric drive consisting of a diesel engine to generate electrical power for mobility and all other vehicle subsystems.

Taxicabs
Hybrid technology may be particularly appropriate for use as taxicabs, as in many locations they are used in predominantly urban environments; have intensive operating schedules, maximizing fuel savings over the life of the vehicle; and may spend considerable periods of time at idle, where the hybrid engine may allow for the combustion engine to be shut off (while retaining use of electrical accessories). Hybrid taxicabs are primarily based on production passenger vehicles, with modifications (often aftermarket) to meet specialized usage requirements and/or local regulations (security features, for example). Since vehicles in taxicab service may operate for 10-20 hours per day, the reduction in local pollution and noxious emissions may be more significant than that achieved by hybrids in private vehicle use.

In 2005, New York City added six Ford Escape Hybrids to their taxi fleet and city officials said the entire fleet of 13,000 vehicles could be converted within five years.

Hybrid Drivetrain Types
There are many ways to create an electric-internal combustion hybrid. The variety of electric-ICE designs can be differentiated by the structure of the powertrain, the degree of hybridization and the mode of operation. The main categories are series hybrids and parallel hybrids, with combined hybrids having common characteristics of series and parallel designs.

Hybrids other than electric-internal combustion exist, for example hydraulic and pneumatic hybrids, where compressed fluids and compressed air, respectively, are used for energy storage with regenerative braking.

Gasoline
Gasoline engines are used in most hybrid designs, and will likely remain dominant for the foreseeable future. While petroleum-derived gasoline is the primary fuel, it is possible to mix in varying levels of ethanol created from renewable energy sources. Like most modern ICE-powered vehicles, hybrids can typically use up to about 15% bioethanol. Manufacturers may move to flexible fuel engines, which would increase allowable ratios, but no plans are in place at present.

Diesel
One type of hybrid vehicle combination uses a diesel engine for power generation. Diesels have advantages when delivering constant power for long periods of time, suffering less wear while operating at higher efficiency. The Diesel engine's high torque, combined with hybrid technology, may offer substantially improved mileage. Most diesel vehicles can use 100% pure biofuels (biodiesel), so they can use but do not need petroleum at all for fuel. Petroleum is still the leading source of engine lubrication, although synthetic oils see broad usage. If diesel-electric hybrids were in use, this benefit would likely also apply. Diesel-electric hybrid drivetrains have begun to appear in commercial vehicles (particularly buses); as of 2007, no light duty diesel-electric hybrid passenger cars are currently available, although prototypes exist.

Diesel-electric hybrids with parallel drivetrains like the Prius may have a substantial cost disadvantage to other options. Diesel engines are generally more expensive than gasoline equivalents, due to the demands for higher compression (although this also makes diesels more durable). If this "diesel premium" is added to any additional expense for the hybrid, the diesel-electric combination may make the payback period for such vehicles even longer and less feasible for many consumers. In addition, the higher torque of diesel engines may obviate one of the advantages of the electric motors. As with regular diesel engines, diesel-electric hybrids may be more appropriate for high-mileage, intensive-use applications, such as buses, trucks, and delivery vehicles, and less appropriate for passenger vehicles. In addition, regular diesel vehicles may get similar mileage to gasoline-electric hybrids, for a smaller premium, and the marginal benefit of "hybridization" may not be viable.

Diesels are not widely used for passenger cars in the United States, as US diesel fuel has long been considered very "dirty", with relatively high levels of sulfur and other contaminants in comparison to the Eurodiesel fuel in Europe, where greater restrictions have been in place for many years. Despite the dirtier fuel at the pump, the US has tough restrictions on exhaust, and it has been difficult for car manufacturers to meet emissions levels as higher sulfur levels are damaging to catalytic converters and other emission control systems. However, ultra-low sulfur diesel was mandated and became widely available in the U.S. in October 2006 for highway vehicles, which will allow the use of newer emissions control systems.

Diesel-electric motors are common for use as locomotives, but using a serial hybrid design. In locomotives, the diesel engine is used to generate electricity for the electric drivetrain. This configuration allows the internal combustion engine to be operated at more efficient operating parameters, while removing the need for a separate transmission for the ICE unit and allowing the efficient delivery of torque from the electric motors. Such a system may need a smaller diesel engine and allow for better emissions controls, since the operating range of the diesel engine would be optimized for electric generation rather than power delivery through the mechanical transmission and wheels. There have been studies of this type of diesel-electric hybrid, but there are no confirmed attempts to commercialize such a vehicle for passenger use.

PSA Peugeot Citroën has unveiled two demonstrator vehicles featuring a diesel-electric hybrid powertrain: the Peugeot 307 and Citroën C4 Hybride HDi (PDF). VW made a prototype diesel-electric hybrid car that achieved 2 litres/100 km (118 mpg US) fuel economy, but has yet to sell a hybrid vehicle. General Motors has been testing the Opel Astra Diesel Hybrid. There have been no concrete dates suggested for these vehicles, but press statements have suggested production vehicles would not appear before 2009.

So far, production diesel-electric engines have mostly just appeared in mass transit buses. Current manufacturers of diesel-electric hybrid buses include New Flyer Industries, Gillig, Orion Bus Industries, and North American Bus Industries. In 2008, NovaBus will add a diesel-electric hybrid option as well.

Benefits
Benefits of the hybrid design include:
 * Current hybrid vehicles reduce petroleum consumption (compared to otherwise similar ICE vehicles) primarily by using three mechanisms: a) Reducing wasted energy during idle/low output, generally by turning the internal combustion engine off; b) Recapturing waste energy (i.e. regenerative braking); c) reducing the size and power of the ICE engine, and hence inefficiencies from under-utilization, by using the better torque response of electric motors to compensate for the loss in peak power output from the smaller internal combustion engine. Any combination of these three primary hybrid technologies may be used for different fuel usage, power, emissions, weight and cost profiles.
 * Hybrids may also make more aggressive use of other fuel-saving techniques, such as reduced weight; these are not advantages of the hybrid design, but engineering choices made for various reasons, including marketing to consumers conscious of these issues.
 * Trade-offs include higher weight for electric motors and batteries, which may reduce fuel efficiency at highway speeds compared to otherwise equivalent ICE vehicles, or even result in lower fuel efficiency at highway speeds than in urban use; for this reason, hybrids may be considered to be particularly well suited to urban applications.
 * The internal-combustion engine in a hybrid vehicle is smaller, lighter, and more efficient than the one in a conventional vehicle, because the combustion engine can be sized for slightly above average power demand rather than peak power demand. A standard combustion engine is required to operate over a range of speed and power, yet its highest efficiency is in a narrow range of operation—in a hybrid vehicle, the combustion engine operates within its range of highest efficiency. The power curve of electric motors is better suited to variable speeds and can provide substantially greater torque at low speeds compared with internal-combustion engines.
 * Like many electric cars, but in contrast to conventional vehicles, braking in a hybrid is controlled in part by the electric motor which can recapture part of the kinetic energy of the car to partially recharge the batteries. This is called regenerative braking and contributes to the higher efficiency of hybrid cars. In a conventional vehicle, braking is done by mechanical brakes, and the kinetic energy of the car is wasted as heat.
 * Hybrids' greater fuel economy has implication for reduced petroleum consumption and vehicle air pollution emissions worldwide
 * Reduced wear on the gasoline engine, particularly from idling with no load.
 * Reduced wear on brakes from the regenerative braking system use.
 * Reduced noise emissions resulting from substantial use of electric motor at low speeds, leading to roadway noise reduction and beneficial noise health effects.  Note, however, that this is not always an advantage; for example, people who are blind or visually-impaired, and who rely on vehicle-noise while crossing streets, find it more difficult to do safely.
 * Reduced air pollution emissions due to lower fuel consumption, leading to improved human health with regard to respiratory and other illness. Composite driving tests indicate total air pollution of carbon monoxide and reactive hydrocarbons are 80 to 90 percent cleaner for hybrid versus conventional vehicles. Pollution reduction in urban environments may be particularly significant due to elimination of idle-at-rest.
 * Increased driving range without refueling or recharging, compared with electric vehicles and perhaps even compared with internal-combustion vehicles. Limitations in range have been a problem for traditional electric vehicles. Hybrids may have substantially longer "operating hours" per unit of petroleum in certain conditions than the mileage-rated fuel efficiency figures may indicate, due to the reduction of idle-at-rest.

Incentives for hybrids and taxes for traditional vehicles
In order to encourage the purchase of hybrid vehicles, several incentives have been made into law:

Canada

 * Residents in Ontario, Canada can claim a rebate on the Provincial Retail Sales Tax of up to $2,000 CDN on the purchase or lease of a hybrid vehicle.

United States

 * Starting January 1, 2006, the purchase of hybrid cars qualifies for a tax credit up to $3400 on the purchaser's Federal income taxes. The tax credit is to be phased out two calendar quarters after the manufacturer reaches 60,000 new cars sold in the following manner: it will be reduced to 50% ($1700) if delivered in either the third or fourth quarter after the threshold is reached, to 25% ($850) in the fifth and sixth quarters, and 0% thereafter.
 * Hybrid purchases before January 1, 2006 qualify for a tax deduction on the IRS 1040 form. In 2003 hybrid owners qualified for a $2,000 deduction; the deduction reduces by $500 each year until it reaches zero. HR 1308 Sec. 319 proposed the phasing out of the deduction to put on hold for the year 2004 and 2005; (i.e., hybrid car buyers can enjoy the $2,000 deduction before the phasing-out resumes at $500 in 2006).
 * Many states give additional tax credits to hybrid car buyers
 * Certain states (e.g., New York, California, Virginia, and Florida) allow singly-occupied hybrid vehicles to enter the HOV lanes on the highway. Initially, the Federal Highway Administration ruled that this was a violation of federal statute until August 10 2005 when George W. Bush signed the Transportation Equity Act of 2005 into law.
 * Some states, e.g. California, exempt hybrid cars from the biennial smog inspection, which costs over $50 (as of 2004).
 * Hybrid cars can go on certain toll roads for free.
 * The city of San Jose, California issues a free parking tag for hybrid cars that were purchased at a San Jose dealership. The qualified owners do not have to pay for parking in any city garage or road side parking meters.
 * City of Los Angeles, California offers free parking to all hybrid vehicles starting on October 1 2004. The experiment is an extension to an existing offer of free parking for all pure electrical vehicles.
 * In October, 2005, the City of Baltimore, Maryland started to offer discount on monthly parking in the city parking lots, and is considering free meter parking for hybrid vehicles. On November 3 2005, the Boston Globe reports that the city council of Boston is considering the same treatment for hybrid cars.
 * Annual vehicle registration fees in the District of Columbia are half ($36) that paid for conventionally vehicles ($72).
 * Other proposed ones

Netherlands
The new Vehicle Registration Taxes, payable when a car is sold to its first buyer, can earn the owner of a hybrid a discount up to €6000.

Republic of Ireland

 * A 50% reduction in Vehicle Registration Tax (VRT) applies, which normally amounts to 25% of the market value of a car.

United Kingdom

 * Drivers of hybrid vehicles in the United Kingdom benefit from the lowest band of vehicle excise duty (car tax) which is based on CO2 emissions. In London, these vehicles are also exempt from the £8 ($14) daily congestion charge in central London. Due to their low levels of regulated emissions, the greenest cars are eligible for 100% discount under the current system.


 * To be eligible the car must be on the current Power Shift Register. At present, these include the cleanest LPG and natural gas cars and most hybrid-electric, battery electric vehicles and fuel cell-electric vehicles.

Expense
Hybrid vehicles are more expensive (the so-called "hybrid premium") than traditional internal-combustion vehicles, due to extra batteries, more electronics and in some cases other design considerations. The trade-off between higher initial cost and lower fuel costs (often referred to as the payback period) is dependent on usage - miles traveled, or hours of operation, and fuel costs. Traditional economy vehicles may result in a lower direct cost for many users (before consideration of any externality).Consumer Reports ran an article in April 2006 stating that hybrids would not pay for themselves over 5 years of ownership. However, this included an error with charging the "hybrid premium" twice. When corrected, the Honda Civic Hybrid and Toyota Prius did have a payback period of slightly less than 5 years. This includes conservative estimates with depreciation (seen as more depreciation than a non-hybrid, although that is not the current norm) and with gas prices. In particular, the Consumer Reports article assumed $2/gallon for 3 years, $3/gallon for one year and $4/gallon the last year. As recent events have shown, this is a volatile market and hard to predict. For 2006, gas prices ranged from low $2 to low $3, averaging about $2.60/gallon.

Many hybrid owners have justified their purchase through other, more traditional means. Most cars are not purchased solely on an economic basis, as evidenced by the prevalence of automatic transmission, power windows and air-conditioning, not to mention any new car vs. used, luxury cars and even large SUVs owned by office workers. Instead, cars that meet the owner's affordability range are considered, and the one with the best set of features for that owner is selected. In this case, the feature set includes lower contribution to global warming gases (beyond that of simple fuel efficiency gains, for Toyota and some other manufacturers), less pollution which is shown to cause and exacerbate respiratory afflictions like asthma, sending a message to the manufacturers that demand exists for a car that takes environmental effects into consideration, and sending less money to oil-producing countries (a large component of the U.S. trade deficit).

CNW Marketing Reports
Art Spinella of CNW Marketing has released reports critical of hybrids, particularly their claim of economic benefits. One widely-released report in 2005, the in-depth Dust-to-Dust study (from production to disposal of a vehicle) found that hybrids fared worse than large SUVs. In particular, a Toyota Prius cost $3.24/mile to build, operate and dispose/recycle, whereas a Chevy Tahoe or GMC Yukon cost $2.93/mile. (For comparison purposes, a Hummer H3 was $2.065/mile, an Audi A6 was $4.96/mile, a Toyota Echo was $.70/mile and a Jeep Wrangler was $.60/mile. Other hybrids were roughly similar to the Prius, the Honda Insight was the best at $2.94/mile). However, these numbers are not without dispute. The CNW report estimated that a Prius cost $354,000 over its lifetime of 109,000 miles, and a Chevy Tahoe cost $787,000 over 268,000 miles and a Ford Excursion cost a whopping $888,000 over 269,000 miles. There are two issues with this &mdash; the simpler one being that a Prius will have an average lifespan of much more than 109,000 miles. It is a recently introduced car, but several incidental cases of the Prius operating more than 200,000 miles on the original batteries have been reported. Assuming an industry-average lifespan of 178,000 miles, the Prius would then only cost $2.28/mile, beating all large SUVs and full-size pickups. .

The second issue is the lifetime cost of a vehicle. Operating costs are fairly well-known, limited largely to fuel, repairs and maintenance. The initial buyer of the vehicle must pay for the mining, manufacturing, assembly, design and overhead of all components of the vehicle (assuming there is no massive government subsidy common to all industrialized nations). Otherwise the manufacturer or suppliers would be losing large sums of money on each vehicle (many times the price of the vehicle, given the numbers in this report) and quickly go out of business. Since little money changes hands when a car is junked, it is reasonable to assume the disposal of a vehicle is largely paid for by recyclable material (and to some extent, government-subsidized landfills). The report shows large sums of money for each step in the process. Even the cost of transportation of workers to the workplace is covered, although that should be paid by their paycheck. Only government-subsidized road repair seems to be missing in the list of costs (which is affected more by multi-ton vehicles). The large dust-to-dust report does not get into specifics on how double-charging of expenses is avoided (such as steel that is recycled, or workers' costs and their salaries), but a detailed analysis of the whole report is not possible here. Briefly, without the bankruptcy of multiple nations and car manufacturers, the large figures associated with lifetime vehicle costs are highly suspect.

In any case, the less publicized but more recent report for 2006 vehicles (summarizing spreadsheets available only) has adjusted the figures considerably. According to CNW Marketing, hybrids now cost less per mile than large SUVs: the 2006 Prius is reported at $2.87/mile, Chevy Tahoe is $3.76/mile, and Ford Excursion is $4.04/mile. Regardless, until the vehicle lifetime costs can be verified more completely, these reports should be considered with healthy skepticism.

Design Considerations
In some cases, manufacturers are producing hybrid vehicles that use the added energy provided by the hybrid systems to give vehicles a power boost, rather than significantly improved fuel efficiency compared to their traditional counterparts. The trade-off between added performance and improved fuel efficiency is mainly something controlled by the software within the hybrid system. In the future, manufacturers may provide hybrid-owners with the ability to set this balance (fuel efficiency vs. added performance) as they wish, through a user-controlled setting. Toyota announced in January, 2006 that it was considering a "high-efficiency" button.

Hybrids vs. electric vehicles
Battery powered all-electric cars (BEVs) are more popular in Europe than in the U.S. Most European electric vehicles are purchased from manufacturers, while due to unavailability of manufactured vehicles, most U.S. vehicles are owner-built conversions of older conventional vehicles. The major U.S. automobile manufacturers argue that customer demand for pure electric cars is small. In addition, the long suburban commutes common in the U.S. make range an important criterion for electric vehicle design. However, if advances in battery technology allow increased range at comparable cost to gasoline-powered vehicles, manufacturers will likely mass-market electric vehicles. The relative cost of gasoline to an equivalent amount of electrical energy will also be a critical factor in the electric vehicle market.

Another relevant factor is the ultimate source of power for the electric vehicles. In areas where older coal-fired generators are the source of electrical power, a pure electric vehicle will be responsible for more of some types of pollution — namely sulfates and particulates — than a hybrid vehicle, while less of other types of pollution, such as carbon monoxide and nitrogen oxide emissions (Table 1). Whether greenhouse gas emissions will be lower in such a case is still under debate. (See vs. .) In any event, the local pollution effects would be lessened by a fleet of electric cars, because the sources of the pollution would be outside of urban areas.

A possible advantage of the hybrid vehicle is in not requiring any upgrades to the electric power transmission grid. Since it can't be scaled larger and smaller at will, the grid is sized so as to carry almost the maximum load (i.e. summer air conditioning) with only occasional failures, and thus has much of its capacity idle most of the time. For the electric utilities, it would be advantageous to utilize that excess capacity and thereby generate a greater revenue for their fixed investment, by selling power to consumers to recharge their vehicles. However, this vision very pointedly does not allow for recharging of vehicles during peak usage times; to do so would require substantial upgrades to the capacity of the grid, and again leave the utilities with excess capacity most of the time. On the other hand, to require consumers to refrain from recharging their vehicles during certain times may not be an easy idea to sell to them.

For now, car manufacturers are focusing on fuel cell-based cars and hybrids. Fuel cell vehicles are being developed in a long-term research environment, rather than with expectations of production at any definite time. Toyota intends all of its vehicles to have a hybrid option by 2012.

Plug in
After market plug in kits are available for some hybrids from third party manufacturers. These greatly increase mileage per unit of petroleum (although overall energy consumption may be the same). Cost savings, toxic pollution and greenhouse gas production will depend on the local electric regime. If electricity generation is located elsewhere, it may reduce local emissions of toxins, an advantage in urban areas. If electricity generation is localized to the charging site using solar panels, it may be possible to reduce overall emissions. See Plug-in hybrid electric vehicle in general, and plug-ins for the Prius.

General

 * Compare hybrid cars.
 * U.S. Federal Income Tax Deduction for Hybrids Placed in Service.

News

 * GM battery development details revealed 2007-03-13 Alternate
 * GM Announces Chevrolet Volt Series Hybrid Concept Vehicle 2007-01-07

Hybrid powertrains

 * ISE ThunderVolt® Electric and Hybrid-Electric Buses and Trucks Drive Systems also using Ultracapacitators
 * Diesel electric hybrid Ricardo i-MoGen Integrated Motor Generator
 * TM4 motor generator
 * Lombardini ECOMOVE Hybrid Power Engine
 * Siemens Integrated Powertrain Management
 * Series, Parallel, and series-parallel systems animation
 * Mother Earth News article from 1978 on the original regenerative braking hybrid car
 * Folsom Technologies, Inc. Hybrid Hydraulic, Hybrid Electric, and CVT technologies

Hybrids in logistics

 * Mercedes Hybrid Sprinter
 * SHEP Technologies, Inc. Hydraulic hybrids.
 * Permo-Drive Australian hydraulic hybrids.
 * VOLK Hybrids for baggage and cargo handling on airports.

Hybrids in public transport

 * DaimlerChrysle Orion hybrid buses.
 * Hybrid-Electric "Bus of the Future" Tested By Capital Metro.

EU

 * Council Directive 70/156/EEC, about Type-approval of motor vehicles and their trailers.
 * Council Directive 80/1267/EEC: Amendment of Directive 70/156/EEC
 * Council Directive 80/1268/EEC Fuel consumption of motor vehicles.