GM and DaimlerChrysler to Partner on Hybrids
Seattle: Diesel Hybrid Buses with GM Drive Falling Short on Fuel Economy

GM, DaimlerChrysler Partner on Two-Mode, Full Hybrid System

GM and DaimlerChrysler are working together on a two-mode, full hybrid system that could support a range of applications, from compact cars to large SUVs, including front-wheel and read-wheel drives, and using a variety of powertrains including diesel, gasoline, and possibly alternative fuel systems.

When participating on a conference panel in Oct 2003, mid-level engineering managers from both companies discovered that they had similar notions and work in progress on the design of such a hybrid drive. That conference planted the seed for the cooperation announced today. 


The two-mode full hybrid system described is conceptually an implementation of GM’s Advanced Hybrid System II, currently used in its diesel-hybrid transit buses, and planned for implementation in a downsized version in the Tahoe and Yukon SUVs in 2007. At the announcement, both companies were very careful to state that while GM has numerous patents in this area, Chrysler has significant work in process as well; in other words, this is not a tech licensing or transfer deal from GM to DaimlerChrysler. Both companies have cooperated together in the past on the development of transmissions.

The proposed system is, in essence, an electrically variable transmission with two hybrid drive modes provided by a variable pairing of two electric motors. The first mode is for low-speed, stop-and-start, in-city driving. The second is for highway driving—an area in which other single-mode hybrids have not performed as well as expected. As noted in this earlier post, in road-testing, Mercedes’s F500 MIND diesel hybrid prototype delivered worse fuel economy in highway driving than the conventional diesel. The two-mode architecture is intended to correct that type of result.

This system will reduce fuel consumption at highway speeds much more effectively than available single-mode systems and achieve at least a 25% improvement in composite fuel economy in full-size truck applications.

—Tom Stephens, Group Vice President, GM Powertrain

The system relies on two electric motors coupled to two gearsets rather than a single motor to provide a more flexible range of operating power, control and efficiency than obtained with a single-motor implementation. By using gearing to selectively amplify the power from the electric motors, the system can use smaller motors, inverters and batteries, thereby reducing mass and cost while maintaining or increasing hybrid efficiency.

In the first mode, for low-speed and light loads, the system can operate just with the engine, just with the motor, or with any combination of the two. In this mode, one motor acts as a generator, while the other provides drive (motor) power. In the second, both motors selectively operate in motoring or generating modes depending upon the vehicle speed.

By taking this approach, the companies are increasing the mechanical complexity of the system and the accompanying requirements for sophisticated engine control software.

The first products stemming from this partnership will be the GM Yukon and Tahoe SUVs in 2007, followed shortly thereafter by the Dodge Durango. The partnership isn’t accelerating the arrival of the first new full hybrid models to market, but it presumably is helping (a) to ensure that those first vehicles will roll out as previously announced, (b) that they can be manufactured in sufficient volume to meet demand and (c) that the companies can accelerate the implementation of the hybrid drive across multiple platforms more quickly and cost-effectively.

One of the major pragmatic advantages of this approach, according to both companies, is the reduced size required to package the system due to the use of smaller components. Ultimately, they’d like to be able to take an existing powertrain and replace the conventional transmission with the appropriate two-mode hybrid drive and get comparable tractive results while dramatically reducing fuel consumption and emissions. The ability to package the system in a compact form factor is an essential element to achieve that goal.

Neither company in the past has been an outspoken avocate of hybrid technology—almost the opposite. GM has focused visibly on fuel cells and DaimlerChrysler on clean diesels as well as fuel cells. Yet their hybrid work had been ongoing, as evidenced by the 60+ patents GM holds in the area and by the work DaimlerChrysler was doing with its diesel-hybrids. Despite the very low market penetration that hybrids currently have, the two companies now foresee rapid market growth to perhaps 15%+ in the coming years. Definitely a market size of substantial interest, and one that they cannot afford to cede to the competition—especially Toyota and Honda.

We see the world fragmenting into many technologies...we are working across many at DaimlerChrysler: clean diesel, displacement on demand, the role of internal combustion engines, hybrids...

—Eric Ridenour, Executive Vice President of Product Development, Chrysler Group

GM has an advanced propulsion technology strategy...we are trying to improve fuel economy, and we’d like to take emissions down to zero. There is no silver bullet. We have to work on every on of these fronts [fuel cell vehicles, hybrids, alternative fuel vehicles, clean diesel, gasoline]. The issue is how do we improve fuel economy? How do we reduce CO2? How do we move forward with more environmentally friendly vehicle applications? Hybrids are not a silver bullet. But as the market grows, DaimlerChrysler and GM will partner together, collaborate together, and have a very important presence in that market.

—Tom Stephens, Group Vice President, GM Powertrain


richard schumacher

Clutches? Eww. I won't buy one because it will surely be less reliable than Toyota's design.

Jim Summers

I'd like to know how the addition of three clutches and an extra planetary gear set make this design any better than Toyota's (or Honda's). Why are clutches even necessary, given the planetary gears?

The only advantage to this design is that it might not infringe on Toyota's patents, so there will be no need to share Ford's embarrassment and pay royalties to Toyota.


I’ll see if I can get someone from Toyota and someone from GM to weigh in, or find an analysis.

Bob Allen

I'm happy to see GM openly embracing hybrid technology. While I remain skeptical, I think that competition in the development of environmentally friendly cars will benefit all of us.
The problem I see is that GM is still committed to producing huge vehicles that are wasteful of other resources besides fuel. I'd like to see some "maturing" of the adolescent American motor ethic away from raw horsepower and size into vehicles that make more sense. A man buys a 6000 lb truck because he needs to tow a trailer; he tows the trailer once or twice a year, but has to haul the 6000 lb truck around all year. One could build three smaller trucks from the materials used to make two Tahoes. How many soccer moms actually need an off road capable vehicle with lousy mileage?
Huge SUV's are death traps because they roll over more easily and can more easily go out of control. Moreover, they are a menace to people driving more reasonably sized cars. Why perpetuate a race among consumers to be the biggest car on the block?
In the court of world opinion, which the Bush Administration cares not a lick about, we are seen as piggy and over consumptive. This, I venture, is a major root cause for anti-American violence around the world, NOT our freedoms or the education of women.

Ian Flamm

Who are they kidding, their system is simpler!!! Toyota's Synergy Drive has one set of planetary gears,a CVT transmission, and yes two electric motors in series. GM and DaimlerChrysler's spinmeisters were having a great time at the public's expense. A 25% gain in fuel economey is admirable if their vehicles got respectable fuel economy in the first place. But when they start out in the low teens for gas mileage, with all the extra weight and ineffiencies of their new "better" system, what do they actually gain, the high teens for fuel mileage?


hybrid systems are not needed in a small car as much as they are needed in large to very large truck or even bus. you already get good gas mileage in a small car. 2 mode system will be industry standard. take that to the bank, John


Valo vabe kaj kam borben ok


ll my ways she wove of light,
Wove them all alive,
Made them warm and beauty bright...
So the trembling ambient air
Clothes the golden water where
The pearl fishers dive.

When she wept and begged a kiss
Very close I'd hold her,
And I know so well in this
Fine fierce joy of memory
She was very young like me
Though half an aeon older.

Once she kissed me very long,
Tiptoed out the door,
Left me, took her light along,
Faded as a music fades...
Then I saw the changing shades,
Color-blind no more.


Dear Sir/Madam

It gives us great pleasure to make this announcement

After five and a half years Genrod Turbo Diesel situated in South Africa has tested the first prototype of a unique hybrid drive system
Test carried out have shown that a pick up truck using an average of 13.5 litres per 100 km can now look forward to a consumption figure of 6.5 litres per 100 km

Further development of this system will reduce this figure even further

The beauty of this system is its adaptability.It can be used in passenger cars,pick up trucks ,light commercial vehicles,inner city busses,generator sets,these are just a few examples of it` versatility

We would like to ask your esteemed company if you would be interested in joining us as an investment partner or to purchase the project outright

This really is a very exciting project and has than potential to change motoring forever

We look forward to your answer in anticipation

Best regards
Gavin Rodel

TEL + 27 34 9809704
TEL + 27 34 9809722
FAX + 27 34 9821911
E MAIL [email protected]

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