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Hybrid Vehicle Portfolio
Producing hybrid vehicles is one piece of GM’s three-part strategy to improve fuel consumption and reduce vehicle emissions, along with improving the efficiency of the traditional internal combustion engine and developing hydrogen fuel cell vehicles. GM is applying hybrid technologies to high-volume and high fuel consumption vehicles first to save as many litres of fuel as possible.
GM's Hybrid Timeline
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2008 |
By the end of 2008, GM will offer eight hybrid models, estimated to be more than any automotive manufacturer in Canada. |
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2007 |
The Chevrolet Tahoe and GMC Yukon Hybrids become the world's first full-size hybrid SUVs, using an innovative new two-mode hybrid system. |
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2006 |
The Saturn VUE Green Line Hybrid becomes the first GM vehicle powered by a new, more affordable hybrid system. |
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2005 |
Hybrid pickups were made available to retail customers and 85 hybrid buses were delivered to 9 cities in North America. |
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2004 |
Hybrid versions of the Chevrolet Silverado and GMC Sierra pickup become the first full-size hybrid pickup trucks and the first hybrids offered by a U.S. manufacturer, providing a 10% improvement in fuel efficiency. |
GM first introduced hybrid technology for mass transit buses in 2003, and then in 2004, introduced the world’s first hybrid pickup trucks. GM continues to roll out a very diverse hybrid portfolio with a plan to produce and sell 12 hybrid models in Canada. GM Hybrid vehicles available in 2008 are as follows:
- Cadillac Escalade
- Chevrolet Malibu
- Chevrolet Silverado
- Chevrolet Tahoe
- GMC Sierra
- GMC Yukon
- Saturn Aura Green Line
- Saturn Vue Green Line
These vehicles will come equipped with one of two different hybrid systems designed to meet Canadian driving patters and needs. The systems vary in fuel consumption savings and cost, providing an opportunity for more consumers to own a hybrid vehicle and benefit from increased fuel consumption savings.
GM's Hybrid Technologies
The driving situation determines whether the vehicle operates in either motoring or generating mode. In motoring mode, the hybrid system is used to quickly restart the gasoline engine upon brake pedal release and provide momentary acceleration assistance as needed, such as during a passing manoeuvre. In the generating mode, the hybrid system is used to provide both 12-volt accessory power and power to charge the battery pack. To perform these functions, the engine is used to power the motor/generator unit, which then provides a three-phase electrical output. The three-phase AC electrical output of the motor/generator is then converted to DC energy to efficiently charge the hybrid battery pack and vehicle accessory battery. This hybrid system is also designed to automatically maintain full accessory functionality, including climate control, when the vehicle is stopped, so that hybrid operations are transparent to the driver and passenger. This hybrid system allows an appropriate balance between fuel economy and comfort by providing a system, with two driver-selectable operating modes. An economy mode favours fuel economy by limiting the effect of air conditioning, while the other mode favours maximum passenger comfort and defogging performance. |
The first mode of the system is for low speed and light loads. In this mode, the hybrid system can operate with electric power only, engine power only and any combination of engine and electric power. When the first mode operates as electric only, fuel consumption is reduced in heavy stop-and-go traffic by shutting off the engine for extended periods of time and moving exclusively under electric power at low speeds. The second mode is primarily used at highway speeds. In addition to electric assist, the second mode integrates sophisticated electronic controls, such as Active Fuel Management, cam phasing and late-intake valve closure, to allow even more efficient engine operation with electric motors less than half the size of traditional "one-mode" hybrid system. Full eight-cylinder engine power is provided when conditions demand it, such as passing, towing or climbing a steep grade. The two-mode system also leverages a four-speed automatic transmission and electronic controls in an integrated, powerful and compact system that can be used with gas and diesel engines, front- and rear-wheel-drive configurations and cars, trucks and SUVs. The Two-Mode hybrid system uses two electrically continuously variable transmission (ECVT) modes of operation that optimize power and torque for various conditions. The addition of the second mode to the drive system improves efficiency and reduces the need for large electric motors, which are used in single-mode systems. The smaller motors are lighter and more easily package in the space of a typical automatic transmission. The ECVT modes are combined with four fixed gear rations for high efficiency and power handling capabilities in a broad variety of vehicle applications. The combination of the two ECVT modes and four fixed gear rations allows for the efficient operation throughout a vehicle's operating range, at low and high speeds. Also, a sophisticated electronic control module constantly optimizes the entire hybrid powertrain system to select the most efficient operation point for power level demanded by the driver. |
Belt Alternator System - is GM's more affordable hybrid system and is offered in the Saturn Vue and Saturn Aura. Depending on driving conditions, this technology allows for an estimated 20 percent improvement in fuel consumption over the conventional gas engine. The vehicle uses sophisticated controls and a unique electric motor/generator mated to a 2.4L VVT four-cylinder engine and 4T45E four-speed transmission. The 2.4L hybrid powertrain is rated at 170 horsepower.
Two-Mode Hybrid System - is available on selected GM full-size SUV and pick-up trucks and will deliver improved fuel consumption and power, while maintaining the capabilities of a full-size SUV. When combined with Active Fuel Management, the two-mode hybrid system will offer a 25 percent fuel consumption. Using this system on full-size SUVs is part of GM's strategy to apply advanced technologies on high-volume, higher fuel-consuming vehicles segments first.