That was then. More recently, DaimlerChrysler joined with GM and BMW in a ground-breaking partnership that's cooperating on a new form of hybrid technology called the Two-Mode Hybrid System.
In the not-so-long-term, DaimlerChrysler, GM, and BMW have teamed to develop an innovative
Slated to appear late in 2007 on board the'08 Chevy Tahoe and GMC Yukon, and later on the '08 Dodge Durango, the Two-Mode System houses two 60 kW electric motors inside an automatic transmission. The motors are used to assist the internal combustion engine in two different ways: One mode for low vehicle speeds and light loads, the other to boost performance at high engine speeds and in high-power-demand situations, like towing. As with current full hybrid systems, the Two-Mode will allow the trucks to operate only on electric power at low speeds, and will include a start/stop function that shuts off the engine at idle, a key component to getting high mpg numbers in city driving. Power for the motors will be stored in a 300-volt nickel-metal-hydride battery pack located under the second-row seat.
The electronic controls inherent in the Two-Mode System "will allow you to use our Displacement on Demand technology more aggressively," said Dana Kaplinski, assistant chief engineer for GM's side of the Two-Mode System. "You have more ability to save fuel because you can disable the cylinders across a wider driving range." When mated to an engine with GM's Displacement on Demand or DaimlerChrysler's Multi-Displacement System, the Two-Mode is expected to deliver a 25 percent improvement in overall fuel efficiency.
Another advantage: Because it's being developed by three different companies, they can share the development and engineering costs so that, in theory anyway, the premium for the hybrid system won't be as high as we've seen on other trucks. Officially, "pricing hasn't been released, but we'll be competitive," said Kaplinski.
This schematic from GM shows the differences between the Two-Mode system's operating range
Toyota, too, is working on adapting a full hybrid system to its pickup trucks. A recent news story from Reuters said the company has plans for a "cheaper, smaller" hybrid system, available in 2008, that will slash its premium by half and allow its use on a broader range of vehicles. Toyota's eventual aim is to offer a hybrid powertrain on every vehicle it sells.
But Paul Williamsen pointed out the challenges Toyota's faces. "Our current AWD hybrid system for the Highlander is not a body-on-frame system with driveshafts to both sets of wheels. There is no rear driveshaft; it uses complete electronic control of the rear wheels. That has its advantages; you can instantaneously add torque to the rear wheels, and no internal-combustion engine can do that." But how do you adapt that system to a pickup? Turn the Highlander system around so there's mechanical control of the rear wheels and electric power to the fronts? That's a possibility, said Williamsen, "but that presents some packaging issues. [The front end] is a busy place, and about the worst place to put more mass." Plus, the high amounts of torque from an electric motor "could spin a front hub apart very easily."
If Toyota can release a new truck-based hybrid system in 2008 or thereabouts, and the GM/DaimlerChrysler Two-Mode System stays on schedule, we off-roaders may actually have some viable hybrid choices in the near future. We can only hope that the premium paid for the technology goes down, because we're pretty sure gas prices won't.
Ford Escape/Mercury Mariner
Hybrid System Full
Hybrid EPA Fuel Economy (city/highway) 33/29
Conventional EPA Fuel Economy (city/highway) 21/24 (I-4 engine)
Hybrid MSRP $29,140 (Escape AWD), $29,840 (Mariner AWD)
Conventional MSRP $24,285 (Escape XLT AWD), $25,035 (Mariner Luxury AWD)
Estimated 2006 Tax Credit $1,950
Chevrolet Silverado/GMC Sierra
Hybrid System Mild
Hybrid EPA Fuel Economy (city/highway) 17/19
Conventional EPA Fuel Economy (city/highway) 15/19
Hybrid MSRP $36,705 (Silverado extended cab 4x4)
Conventional MSRP $35,205 (Silverado extended cab 4x4 with Vortec 5300 V-8)
Estimated 2006 Tax Credit $650
Toyota Highlander/Lexus RX 400h
Hybrid System Full
Hybrid EPA Fuel Economy (city/highway) 31/27
Conventional EPA Fuel Economy (city/highway) 18/24
Hybrid MSRP $34,430 (Highlander AWD), $48,535 (Lexus AWD)
Conventional MSRP $27,840 (Highlander AWD V-6 w/third-row seat), $37,770 (Lexus RX 330 AWD)
Estimated 2006 Tax Credit $2,200