by We have developed hybrid power systems capable of powering many of our vehicles. Hybrid electric propulsion systems combine internal combustion engines and electric drives to dramatically increase fuel efficiency. Current production vehicles include buses (Allison Electric Drive Hybrid System, referred to as the EP parallel system) and full-size pickups (flywheel alternator starter system). The biggest gains in fuel savings from hybrid technology are in the largest vehicles with the highest fuel consumption. By focusing on these vehicles first, we can make a greater impact on reducing fuel consumption.
In addition to the EP parallel system in our hybrid buses and the flywheel alternator starter system in our full-size pickups, we are developing other hybrid propulsion system architectures:
* BAS (Belt Alternator Starter)
* AHSII (Advanced Hybrid System II)
These Chevrolet Silverado trucks are equipped with hybrid techology.
Hybrid Trucks
The hybrid powertrain is one of a wide range of technologies we are using to maintain our progress in light truck fuel efficiency. We are currently offering the industry’s first hybrid pickup truck, which features a conventional powertrain and driveline with an electric motor integrated between the engine and transmission.
The engine provides the same performance as today's V-8 Vortec engines, but improves fuel efficiency by 10%. These full-size Chevrolet Silverado and GMC Sierra pickups can be equipped with flywheel alternator starter technology and are currently available to our fleet customers. Retail customers in California, Oregon, Washington State, Nevada, Alaska and Florida can place orders at their local dealers now.
Along with our FAS (flywheel-alternator-starter) system we offer the BAS (belt-alternator-system).
Flywheel Alternator Starter (FAS) System
GM hybrid pickup trucks get more miles from each gallon of gasoline mainly because of the engine start/stop function and regenerative braking, which turn the motor into a generator as the truck decelerates. Extra fuel savings come from quickly shutting off fuel any time the truck is coasting or braking, using the electric motor to make the transition seamless to the driver.
Instead of a conventional starter motor and alternator, the hybrid truck features a compact electric motor integrated between the engine and transmission, known as a flywheel alternator starter system. The 14,000- watt electric motor provides fast, quiet starting power, the ability to generate up to 2,400 watts of continuous electric power, and 10% fuel savings.
The electricity generated by the system has many uses. It may be stored in a 42-volt lead-acid battery pack for future use, used to support on-board electric accessories, operate power tools, or even run essential home appliances during power outages using the pair of 120-volt, 20-amp outlets in the cab and bed. This technology is currently available to fleet and commercial customers throughout the country and is available to retail consumers in Alaska, Washington, Oregon, California, Nevada and Florida.
The FAS system is in production on the 2004 model year Chevrolet Silverado hybrid and GMC Sierra hybrid trucks. The hybrid trucks are available as an extended-cab pickup truck on the Chevrolet Silverado and GMC Sierra. It is equipped with a 42-volt lead-acid battery pack, a modified 4-speed automatic transmission, 5.3L V8 engine, and is available in both 2WD and 4WD.
The GM Hybrid Bus
Hybrid Buses
GM is also applying hybrid technology to mass transit operations across North America.
The state-of-the-art buses, powered by an advanced hybrid-electric powertrain developed by our Allison Transmission division, dramatically reduce emissions from the diesel engine – an environmental plus in Southern California and other metropolitan locations across the United States. Referred to as the EP System, the hybrid-electric powertrain is a "strong" parallel hybrid architecture that is scaleable for various medium- to heavy-duty vehicle platforms.
The EP System can offer up to a 60% improvement in fuel economy and reduction in carbon dioxide over a conventional diesel system in a transit bus application. The technology also can reduce soot particulates by 90%, hydrocarbons by 90%, and nitrous oxide by 50%. These results are based on the Central Business District-14 (CBD-14) operating cycle.
There are 230 GM hybrid-powered buses on the road today in: Seattle/King County, Washington; Philadelphia; Minneapolis; Portland, Oregon; Salt Lake City; Austin and Houston, Texas; Orange County, California; Newark, New Jersey; and Hartford, Connecticut.
There are about 13,000 transit buses in service in the nine largest U.S. cities. If these buses were replaced with those featuring the hybrid system, the United States would use nearly 40 million fewer gallons of diesel fuel every year – the equivalent fuel savings of almost 500,000 small cars with hybrid propulsion systems.
Hybrid bus fact sheet >>
EP System - Parallel Hybrid
The EP hybrid system uses two sources of power: an internal combustion engine and battery-powered electric motors. In the parallel hybrid system, the engine and the electric drive work in concert to provide power to the wheels at different times, depending on speeds and loads.
When the bus accelerates from a stop, the battery-powered electric motors supply powerful acceleration.
Once under way, the parallel hybrid bus uses the diesel engine to maintain speed. At the same time, the engine-generator charges the batteries, giving the vehicle self-sustaining mobility. In addition, the vehicle’s regenerative braking captures energy normally lost as brake heat and returns it to the vehicle’s energy storage system (battery) for reuse. Buses utilizing this technology are currently on the road in major cities across the U.S.
Belt Alternator Starter (BAS) System
GM engineers developed the belt alternator starter (BAS) system to provide improved fuel economy in stop-and-go driving by shutting off the engine at idle and by enabling early fuel cutoff to the engine during decelerations.
The system combines sophisticated engine controls with a precision electric motor/generator. Regenerative braking and efficient charging are also part of this system. The estimated fuel economy savings are about 12%. A single, 36-volt battery provides power, augmenting the existing 12-volt electrical system.
All vehicle accessories and passenger comfort systems, such as air conditioning, function even during the periods when the engine is automatically stopped. Other benefits of the belt alternator starter system include the flexibility to use the system on four and six-cylinder engines, with minimal impact on engine and transmission architectures. It is scheduled to debut in both our car and light truck fleets in 2006.
Advanced Hybrid System II (AHSII)
The Advanced Hybrid System II (AHSII) is a strong hybrid that builds on knowledge from the development of the GM parallel hybrid system for buses. The AHS II versions of the Chevrolet Tahoe and GMC Yukon are scheduled to debut in 2007, and also will feature our Displacement on Demand cylinder deactivation technology.
Used together, these technologies will achieve fuel economy improvement of up to 35%. Using this system on full-size SUVs and pickups is part of GM’s strategy to apply advanced technologies on high-volume, higher fuel-consuming vehicle segments first. Installing a strong hybrid system on a full-size truck will save twice as much fuel per mile as a comparable small hybrid vehicle, with no compromise in performance or utility.
The AHSII uses two sources of power: an internal combustion engine and battery-powered electric motors. In the parallel hybrid system, the engine and the electric drive work in concert to provide power to the wheels at different times, depending on speeds and loads in much the same way as the parallel hybrid.
You can find this article on GM's website. Here is the link. http://www.gm.com/company/gmability/sus ... b.html#fas
Pretty cool stuff.
Guardian
