DaimlerChrysler and GM Join Forces to Develop Two-Mode Full Hybrid Propulsion System
By Mike Hanlon
December 15, 2004
December 16, 2004 DaimlerChrysler and General Motors have announced a cooperative effort to advance the state of hybrid technology. The companies plan to work together to develop a two-mode full hybrid propulsion architecture for applications in GM, Chrysler and Mercedes Car Group vehicles. The full hybrid with two driving modes optimises power and torque for the given driving conditions. The first mode provides tremendous fuel-saving capability in the low-speed and stop-start driving conditions typical of urban commuting, with a combination of full electric propulsion and supplemental combustion engine power. The second mode is used at highway speeds to optimise fuel mileage, while providing full engine power when conditions demand it, such as trailer towing or climbing steep grades. All the driver feels is the satisfaction of low fuel consumption and an ample reserve of power and performance.
Variants planned include rear- and front-wheel-drive versions for cars, trucks and other vehicles.
This technology is expected to improve acceleration performance while also improving vehicle fuel economy and range significantly.
The agreement to date involves GM and DaimlerChrysler signing a non-binding "memorandum of understanding" with the intent to enter into a definitive agreement in early 2005. Both companies have been working independently on their own hybrid propulsion systems for their range of passenger vehicles.
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.
By combining their hybrid development efforts, DaimlerChrysler and GM hope they can position both companies as leaders in this technology. The wide-ranging program will allow opportunities for additional partners, and could become a hybrid source for other auto manufacturers.
Mercedes-Benz will focus on high-tech hybrid propulsion systems in rear-wheel drive passenger cars in the luxury segment. Hybrid technology will be an integral part of its advanced powertrain strategy within the next several years.
The development of a common hybrid propulsion architecture is the basis of the cooperation, while retaining the distinctiveness in feel and performance for the GM, Mercedes Car Group and Chrysler Group brands. The two-mode full hybrid drive system will be mated to different engines and the respective vehicle programs will have unique performance dynamics and calibration.
Each company will integrate the two-mode full hybrid into its own vehicles. Today's typical single-mode systems rely on much larger electric motors than are needed in the patent-protected two-mode system. The two-mode system innovations provide performance and fuel economy improvements at highway speeds and better trailer towing ability.
Packaging is more efficient than today's single mode designs as the system's compact and powerful electric motors are designed to fit within the approximate space of a conventional automatic transmission.
This system will reduce fuel consumption at highway speeds much more effectively than available single mode systems and achieve at least a 25 percent improvement in composite fuel economy in full-size truck applications. In the near term, GM will also continue to expand its offerings of six-speed transmissions and engines equipped with advanced technologies such as variable valve timing and Displacement on Demand.