Electric drive vehicles have been around for a long time (see inset). They continue to ignite the imagination of any number of people and have gathered support across a variety of industries. They have, however, struggled to compete for a place on our highways with our first love, the internal combustion engine. An engine that many of us grew up with on our toys (go-carts), our power tools (lawn mowers) and even our hobbies (motor sports in all of its varieties). Whole industries including after-market parts, the maintenance service and individual vehicle customization industries exist only to support this fascination with internal combustion powered vehicles not to mention the vehicle manufacturers and the fuel suppliers.
The electric power plant has had an uphill battle to unseat the reigning champion of personal transportation for several reasons. One of the fundamental reasons is that energy storage devices, batteries and fuel cells, that provide the on board energy to run the electric motors have been unable to match the range and payload characteristics of the internal combustion engines in conventional use today. Another fundamental problem that has hampered the growth of the electric vehicle is refueling. To compare refueling times to a typical gas/diesel tank refill, even the “fast charge” stations tested in Southern California took longer than the tank refill drivers are used to today. This is not to mention the lack of commercial recharging stations.
At the same time the electric car was developed, work was done on the first hybrid electric vehicle (HEV). One early version developed in 1912 can be seen in the Ford Museum in Dearborn Michigan.
Hybrid power systems were conceived as a way to compensate for the shortfall in battery technology. Because batteries could supply only enough energy for short trips, an onboard generator, powered by an internal combustion engine, could be installed and used for longer trips.1 This technology has three essential components: power units, energy storage systems and propulsion units. Power units could include fuel cells, conventional internal combustion engines and turbine engines. Energy storage devices could be batteries or flywheel systems, and propulsion units can come in the form of electric motors.
These components can be combined in a number of ways including entirely from the electric motor (a series configuration) or direct mechanical input from the engine along with the electric motor (a parallel configuration).
In the Honda Insight and Toyota Prius both the engine (1) and the electric motor (3) are connected to the wheels by the same transmission (2). With the assistance of the electric motor the engine can be smaller.
Intelligent power electronics (4) decide when to use the motor and engine and when to store electricity in advanced batteries (6) for future use. The electric motor is used primarily for low speed cruising or to provide extra power for acceleration or hill climbing.
When braking or coasting to a stop, the hybrid uses its electric motor (3) as a generator to produce electricity, which is then stored in its battery pack (6).
Unlike all-electric vehicles, hybrid vehicles do not need to be plugged into an external source of electricity. Gasoline stored in a conventional fuel tank (5) provides all the energy the hybrid vehicle needs.
Technological Advances that are Enabling HEVs
One of the more important advances affecting HEVs is the availability of effective and affordable regenerative braking systems. This is a way to recover and reuse energy that would ordinarily be dissipated as heat and friction. In a conventional vehicle as the operator engages the brakes to slow down a traveling vehicle, the brake pads grip drums or discs and slow the vehicle. In regenerative braking, some of the energy from the moving vehicle is used to spin onboard generators, which then transfer the resulting electricity back to the batteries, resulting in “regenerative braking”.
Another significant advance aiding this technology is the availability of advanced onboard control systems that constantly monitor the need for power at the wheels and is capable of diverting the system resources to meet the specific requirement.
Changes in vehicle construction materials have also contributed significantly to the development of this technology. High strength low weight body and frame components along with engines built with alloys and materials significantly lighter than the cast iron blocks of the earlier engines have all contributed to improving power to weight ratios in HEVs. This has provided operating performance that approaches conventional engine vehicles.
Why is this important now?
According to the U. S. Department of Energy (US DOE), two-thirds of the oil we consume powers transportation vehicles, and half of that goes to passenger cars and light trucks. The Energy Information Administration is now saying that world oil production is not likely to peak until after 20203. While all of the observers of the world energy situation do not share this view, it is clear that oil production and refinery costs will continue to push market prices higher. This price spiral will help to encourage alternatives (like HEVs) to the oil intensive transportation solutions we use currently.
Perhaps more importantly, the issue of air quality is becoming a sensitive topic across a greater portion of the population.
As the chart indicates, we can continue to expect to add to our air quality issues in the future at the current rates of accumulation.
The third issue is our dependence on oil imports to support our transportation sector activities. The transportation sector has proven to be one area of oil use that has been less successful in curbing use over the last few years:
“In the United States, in contrast to other regions of the world, about 2/3 of all oil use is for transportation, (In most of the rest of the world, oil is more commonly used for space heating and power generation than for transportation.) Gasoline, in turn, accounts for about 2/3 of the total oil used for transportation in the United States. Other petroleum products commonly used for transportation include diesel fuel (used for trucks, buses, railroads, some vessels, and a few passenger autos), jet fuel, and residual fuel oil (used for tankers and other large vessels)”5.
Consumption of oil in stationary uses — residential, commercial, industrial and electricity generation — fell from a peak of 8.7 million barrels daily in 1978 (about 47 percent of total oil use) to a low of less than 6 million barrels per day in the late 1980’s and early 1990’s. Consumption in these sectors has been 6.5-7.0 million barrels per day more recently.
Thus, while oil continues to account for more than 95 percent of all the energy used for transportation in the United States, oil accounts for less than 20 percent of the energy consumed for other, stationary uses, down from 30 percent in 19735.
Over the period from 1973 to 2001 the United States has increased daily imports by over 267% (from 3 million barrels per day to over 8 million barrels per day).
HEV Advantages
Hybrids potentially will provide the market with an effective mechanism to reduce air pollution by a significant amount even though they are not as clean as a pure electric. The engines can be sized for average load rather than peak load which reduces on-board non-payload weight. Fuel efficiency is greatly increased (estimated from a low of 40mpg to a high of 80mpg) and you can exercise greater design freedom for the total vehicle. They also can be supported with the existing infrastructure, which serves to enable an effective transition strategy to cleaner vehicles.
Market Opportunities
Two manufactures have already been convinced that there is real market for these products as evidenced by their introduction of the Honda Insight and the Toyota Prius into their current model lines. Both of these products fit specific customer segments that have use across a broad spectrum of small car applications.
What may be of more interest for those of us that buy and operate heavy and medium duty trucks is the WestStart hybrid-electric truck users forum hosted by Allison Transmission in Indianapolis (January 2002).
Attendees heard representatives from elements of the Department of Defense (including the Army and Air Force) speak about their interest in a development partnership with private industry to turn hybrid-electric trucks into a working reality with a bonafide market presence. The Army specifically has a partnership plan that it calls its 21st Century Truck Initiative:
"This partnership will develop and demonstrate COMMERCIALLY VIABLE truck and propulsion systems technology that will dramatically cut the fuel use and emissions of medium and heavy trucks and buses, while enhancing their safety and affordability and maintaining or enhancing performance."
For the commercial truck buyer, this type of “partnership” has the potential to create viable hybrid-electric trucks in a fraction of the time that they would have taken to develop without this partnership. Additionally, the military represents a significant market for these products with long term commitments for suppliers, which adds to market stability.
Manufacturers Involvement
Beyond Honda and Toyota with their products available today, Daimler-Chrysler, Ford, GM, Mitsubishi and Nissan all have demonstrated HEV pre-production or concept vehicles.
The partnership coordination committee in the 21st Century initiative includes a veritable “who’s who” of the trucking industry. Power plant manufacturers alone include Cummins, Caterpillar, Detroit Diesel and International Truck and Engine.
HEV Outlook
Now that the product technology is past the test/demonstration phase, there is a ready clientele and there is a need for products with these virtues (reducing dependence on foreign oil and reducing exhaust emissions); the future for hybrid-electric vehicles is promising. Just a short 90 years after the first models were developed, we have products that are commercially available. The 21st Century Partnership promises to develop a broader range of products with new solutions to our existing challenges.
The electric power plant has had an uphill battle to unseat the reigning champion of personal transportation for several reasons. One of the fundamental reasons is that energy storage devices, batteries and fuel cells, that provide the on board energy to run the electric motors have been unable to match the range and payload characteristics of the internal combustion engines in conventional use today. Another fundamental problem that has hampered the growth of the electric vehicle is refueling. To compare refueling times to a typical gas/diesel tank refill, even the “fast charge” stations tested in Southern California took longer than the tank refill drivers are used to today. This is not to mention the lack of commercial recharging stations.
At the same time the electric car was developed, work was done on the first hybrid electric vehicle (HEV). One early version developed in 1912 can be seen in the Ford Museum in Dearborn Michigan.
Hybrid power systems were conceived as a way to compensate for the shortfall in battery technology. Because batteries could supply only enough energy for short trips, an onboard generator, powered by an internal combustion engine, could be installed and used for longer trips.1 This technology has three essential components: power units, energy storage systems and propulsion units. Power units could include fuel cells, conventional internal combustion engines and turbine engines. Energy storage devices could be batteries or flywheel systems, and propulsion units can come in the form of electric motors.
1914 Detroit Electric
Photo Courtesy of Auto Collections
Las Vegas, Nev.
These components can be combined in a number of ways including entirely from the electric motor (a series configuration) or direct mechanical input from the engine along with the electric motor (a parallel configuration).
In the Honda Insight and Toyota Prius both the engine (1) and the electric motor (3) are connected to the wheels by the same transmission (2). With the assistance of the electric motor the engine can be smaller.
Intelligent power electronics (4) decide when to use the motor and engine and when to store electricity in advanced batteries (6) for future use. The electric motor is used primarily for low speed cruising or to provide extra power for acceleration or hill climbing.
When braking or coasting to a stop, the hybrid uses its electric motor (3) as a generator to produce electricity, which is then stored in its battery pack (6).
Unlike all-electric vehicles, hybrid vehicles do not need to be plugged into an external source of electricity. Gasoline stored in a conventional fuel tank (5) provides all the energy the hybrid vehicle needs.
Technological Advances that are Enabling HEVs
One of the more important advances affecting HEVs is the availability of effective and affordable regenerative braking systems. This is a way to recover and reuse energy that would ordinarily be dissipated as heat and friction. In a conventional vehicle as the operator engages the brakes to slow down a traveling vehicle, the brake pads grip drums or discs and slow the vehicle. In regenerative braking, some of the energy from the moving vehicle is used to spin onboard generators, which then transfer the resulting electricity back to the batteries, resulting in “regenerative braking”.
Another significant advance aiding this technology is the availability of advanced onboard control systems that constantly monitor the need for power at the wheels and is capable of diverting the system resources to meet the specific requirement.
Changes in vehicle construction materials have also contributed significantly to the development of this technology. High strength low weight body and frame components along with engines built with alloys and materials significantly lighter than the cast iron blocks of the earlier engines have all contributed to improving power to weight ratios in HEVs. This has provided operating performance that approaches conventional engine vehicles.
Why is this important now?
According to the U. S. Department of Energy (US DOE), two-thirds of the oil we consume powers transportation vehicles, and half of that goes to passenger cars and light trucks. The Energy Information Administration is now saying that world oil production is not likely to peak until after 20203. While all of the observers of the world energy situation do not share this view, it is clear that oil production and refinery costs will continue to push market prices higher. This price spiral will help to encourage alternatives (like HEVs) to the oil intensive transportation solutions we use currently.
| Highway Carbon Emissions4 (Millions of Metric Tons) | |||
1990 325 | 2000 386 | 2010 474 | 2020 541 |
Perhaps more importantly, the issue of air quality is becoming a sensitive topic across a greater portion of the population.
As the chart indicates, we can continue to expect to add to our air quality issues in the future at the current rates of accumulation.
The third issue is our dependence on oil imports to support our transportation sector activities. The transportation sector has proven to be one area of oil use that has been less successful in curbing use over the last few years:
“In the United States, in contrast to other regions of the world, about 2/3 of all oil use is for transportation, (In most of the rest of the world, oil is more commonly used for space heating and power generation than for transportation.) Gasoline, in turn, accounts for about 2/3 of the total oil used for transportation in the United States. Other petroleum products commonly used for transportation include diesel fuel (used for trucks, buses, railroads, some vessels, and a few passenger autos), jet fuel, and residual fuel oil (used for tankers and other large vessels)”5.
Consumption of oil in stationary uses — residential, commercial, industrial and electricity generation — fell from a peak of 8.7 million barrels daily in 1978 (about 47 percent of total oil use) to a low of less than 6 million barrels per day in the late 1980’s and early 1990’s. Consumption in these sectors has been 6.5-7.0 million barrels per day more recently.
Thus, while oil continues to account for more than 95 percent of all the energy used for transportation in the United States, oil accounts for less than 20 percent of the energy consumed for other, stationary uses, down from 30 percent in 19735.
Over the period from 1973 to 2001 the United States has increased daily imports by over 267% (from 3 million barrels per day to over 8 million barrels per day).
HEV Advantages
Hybrids potentially will provide the market with an effective mechanism to reduce air pollution by a significant amount even though they are not as clean as a pure electric. The engines can be sized for average load rather than peak load which reduces on-board non-payload weight. Fuel efficiency is greatly increased (estimated from a low of 40mpg to a high of 80mpg) and you can exercise greater design freedom for the total vehicle. They also can be supported with the existing infrastructure, which serves to enable an effective transition strategy to cleaner vehicles.
Market Opportunities
Two manufactures have already been convinced that there is real market for these products as evidenced by their introduction of the Honda Insight and the Toyota Prius into their current model lines. Both of these products fit specific customer segments that have use across a broad spectrum of small car applications.
What may be of more interest for those of us that buy and operate heavy and medium duty trucks is the WestStart hybrid-electric truck users forum hosted by Allison Transmission in Indianapolis (January 2002).
Attendees heard representatives from elements of the Department of Defense (including the Army and Air Force) speak about their interest in a development partnership with private industry to turn hybrid-electric trucks into a working reality with a bonafide market presence. The Army specifically has a partnership plan that it calls its 21st Century Truck Initiative:
"This partnership will develop and demonstrate COMMERCIALLY VIABLE truck and propulsion systems technology that will dramatically cut the fuel use and emissions of medium and heavy trucks and buses, while enhancing their safety and affordability and maintaining or enhancing performance."
For the commercial truck buyer, this type of “partnership” has the potential to create viable hybrid-electric trucks in a fraction of the time that they would have taken to develop without this partnership. Additionally, the military represents a significant market for these products with long term commitments for suppliers, which adds to market stability.
Manufacturers Involvement
Beyond Honda and Toyota with their products available today, Daimler-Chrysler, Ford, GM, Mitsubishi and Nissan all have demonstrated HEV pre-production or concept vehicles.
The partnership coordination committee in the 21st Century initiative includes a veritable “who’s who” of the trucking industry. Power plant manufacturers alone include Cummins, Caterpillar, Detroit Diesel and International Truck and Engine.
HEV Outlook
Now that the product technology is past the test/demonstration phase, there is a ready clientele and there is a need for products with these virtues (reducing dependence on foreign oil and reducing exhaust emissions); the future for hybrid-electric vehicles is promising. Just a short 90 years after the first models were developed, we have products that are commercially available. The 21st Century Partnership promises to develop a broader range of products with new solutions to our existing challenges.
- From the Office of Transportation Technology publication “What is an HEV”.
- From the US Department of Energy (DOE) publication “How do Hybrid Electric Vehicles Work”
- From the Energy Information Administration/International Energy Outlook 2002 publication “Oil Resources in the 21st Century: What Shortage”.
- Source: Transportation Energy Data Book Edition 20, DOE/ORNL-6959, October 2000, and EIA Annual Energy Outlook 2001, DOE/EIA-0383(2001), December 2000.
- From the US DOE publication,
“Oil Market Basics”.
