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2005 GMC Graphyte Concept
2005 GMC Graphyte Concept at the 2005 Detroit Auto Show
By Lou Ann Hammond
With the GMC Graphyte, General Motors announced another hybrid today at the 2005 Detroit Auto Show.
The North American International Auto Show (NAIAS) press days began January 9th. The most well attended show of the year with journalists coming from all over the world, the event will feature 65 introductions of new cars or concepts this week.
The GMC Graphyte Concept is a concept that is not destined for production. It will be a showpiece for General Motors, displaying their ever present, evolving technology.
Last month General Motors announced a partnership with Daimler Chrysler last month utilizing their two-mode hybrid system.
GMC’s Graphyte is a four-wheel-drive or all-wheel-drive mid-size sport utility vehicle (SUV) concept that shows off that two-mode hybrid system. The flexible and cost-effective two-mode full hybrid system will leverage automatic transmission technology and electronic controls in an integrated, powerful and compact system that can be used with a variety of engines, both gas and diesel.
The concept shown was light green in color, but full green in concept. The Graphyte improves fuel economy by 25 percent, saving fuel in stop-n-go and less consumption on the highway or high-torquing situations.
GM previously announced its first application of a full hybrid would be launched in late 2007 in two of GM’s most popular full-size SUVs, the Chevrolet Tahoe and GMC Yukon. Chrysler Group will introduce the two-mode full hybrid system in the Dodge Durango
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a full figured SUV
shortly following the GM SUVs. Mercedes will focus on high-tech propulsion systems in rear-wheel drive passenger cars in the luxury segment.
Th Graphyte Concept can be based on many platforms and engines. The one inside this concept was a Vortec 5300 V-8 , mated to a Hydra-matic automatic transmission.
"The ability to offer a common full hybrid architecture with the flexibility to configure in rear-, front- and all-wheel-drive packages, for both gasoline and diesel engines, gives us the best opportunity for expanding the technology globally. It also provides the basis for co-development with DaimlerChrysler and potential collaborations with other manufacturers," Stephens added.
"It’s the optimal merging of full hybrid and state-of-the-art automatic transmission technologies," said Stephens. "The system is essentially an electrically variable transmission with two hybrid drive modes. We’ve taken the two-mode hybrid technology that we are using in transit buses and improved it further for use in our popular rear-wheel drive SUVs and pickups, and front-wheel drive cars. Single-mode systems can’t provide the range of operating efficiencies that our two-mode system can. Our system reduces fuel consumption at highway speeds much more effectively."
The drive modes alternate seamlessly between the input split mode and a compound split mode. In the input split mode the vehicle can operate on electric, mechanical or a combination of the two. The vehicle operates as a full hybrid when the engine is shut off at low speed and light loads, as leaving the engine off
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luxury with off-road capability
for extended periods of time and moving under electric power is key to reducing fuel consumption in stop and go traffic.
Coupled with the efficient compound split mode, the electronic controller seamlessly integrates with other fuel-saving technologies of advanced engines, such as ultra-high compression ratio, Late Intake Valve Closing (LIVC), Cam Phasing and Displacement on Demand (DoD) to regulate cylinder deactivation. Electric motors not only regulate the power flow, but also aid in extending DoD operation well beyond what is capable without hybrid assist. In addition to electric assist, full–size engine power is on tap whenever higher-load situations demand it, such as towing, climbing steep grades, etc.
"It all happens without the driver realizing it," said Larry Nitz, executive director of GM’s hybrid program. "There are no discernible steps between modes or DoD transitions. The two-mode full hybrid simply optimizes power and torque for the given driving conditions, and all the driver feels is the satisfaction of low fuel consumption and the exceptional reserve power and performance."
"Typical single-mode systems depend on large electric power loops between two large electric motors, resulting in inefficiency and ultimately less continuous power," said Nitz. "The two-mode full hybrid delivers seamless, dependable power on demand and in a more efficient power flow – and is packaged with motors less than half the size of single-mode systems."
The Graphyte was conceived and created at the GM Advanced Studio in Coventry, England.
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big and brutish
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