“The new Chrysler Aspen and Dodge Durango Hemi Hybrid vehicles will offer our customers the sought-after blend of performance, utility, capability and vastly improved fuel economy — all in one package,” said Frank Klegon, Executive Vice President – Product Development, Chrysler LLC. “Combined with Chrysler’s Multi-displacement System (MDS), our advanced, two-mode hybrid technology immediately delivers a more than 25-percent fuel economy improvement to our full-size SUVs — and up to a 40-percent improvement in the city.”

The Chrysler Aspen and Dodge Durango Hemi Hybrid vehicles are Chrysler’s first entries in the hybrid market.

Capable of towing 3 tons, the Chrysler Aspen and Dodge Durango Hemi Hybrid vehicles deliver an estimated 287 kW of power — seamless, dependable power and performance on demand, in an efficient package. With an electrically variable transmission (featuring the best characteristics of an automatic transmission and hybrid drive) and two different hybrid modes of operation, the drive system dramatically improves fuel economy around town and at highway speeds.

The new 5.7-litre Hemi Hybrid is expected to deliver an overall fuel economy improvement of more than 25 percent, including an improvement of nearly 40 percent in the city. For customers who desire the performance and capability of a large SUV, the Chrysler Aspen and Dodge Durango Hybrid vehicles will reduce fuel consumption by thousands of litres of petrol per year.

The renowned Hemi powerplant, in hybrid form, will continue to feature Chrysler’s MDS, which allows the engine to seamlessly alternate between four-cylinder mode when less power is needed and V-8 mode when more power is in demand. The two-mode hybrid system provides assistance from electric motors allowing the Hemi V-8 to remain in four-cylinder mode more often than without a hybrid powertrain, improving overall fuel economy.

Built at the Newark Assembly Plant in Delaware (USA), the new Chrysler Aspen and Dodge Durango Hemi Hybrid vehicles arrive in North American showrooms in mid-2008.

The Advanced Two-mode Hybrid System

Chrysler’s advanced, state-of-the-art two-mode full hybrid system — developed in partnership with General Motors, Mercedes-Benz and The BMW Group — integrates proven automatic-transmission technology with a patented hybrid-electric drive system to deliver the world’s first two-mode full hybrid.

As a result of low- and high-speed electric continuously variable transmission (ECVT) modes, the system is defined as a “two-mode hybrid.” In addition, the sophisticated fuel-saving system incorporates four fixed-gear ratios for high efficiency and power-handling capabilities. During the two ECVT modes, the system can use the electric motors for acceleration, improving fuel economy, or for regenerative braking to utilise energy that would normally be lost during braking or deceleration. The energy is stored in the batteries for later use.

The system’s two modes are optimised for city and highway driving.

In the first mode — at low speed and with light loads — the vehicle can operate in three ways:

• Electric power only
• Engine power only
• Any combination of engine and electric power

The two-mode hybrid provides all of the fuel-saving benefits of a full-hybrid system, including electric-only operation. In this mode, the engine is “shut off,” with the vehicle moving under electric-only power at low speed. The result is a significant reduction in fuel consumption in heavy stop-and-go traffic.

The second mode is used primarily at highway speeds. In addition to electric assist, the second mode provides full power from the 5.7-liter Hemi® V-8 when conditions demand it, such as when passing, pulling a trailer or climbing a steep grade.

The two-mode programming integrates a host of technologies to improve efficiency including Chrysler’s patented Multi-displacement System (MDS), standard on the 5.7-litre Hemi V-8.

An elegantly complex design, the two-mode system also allows for more proliferate packaging via compact and powerful electric motors designed to fit within a conventional automatic transmission space — a clear efficiency advantage compared with today’s typical single-mode systems that rely on much larger electric motors.

A sophisticated controller determines when the vehicle should operate in the first or second mode. Input from the controller determines the necessary torque for the driving conditions and sends a corresponding command to the engine and electric motors. The engine and electric motors transfer torque to a series of gears in the transmission, which multiply torque similar to a conventional automatic transmission to propel the vehicle. Unlike conventional continuously variable transmissions, however, the two-mode full hybrid’s electrically controlled system uses no mechanical belts or bands. Shifts between the two modes are synchronous — meaning no engine speed changes are necessary for the mode shift to occur — resulting in seamless accelerations.

The 300-volt battery pack provides electric power for the system, and is designed to fit in the vehicle without compromising passenger space. A rectifier located under the vehicle’s bonnet converts AC to DC, to power conventional 12-volt accessories, such as interior lighting, climate control and the audio system. The vehicle’s internal-combustion engine efficiently maintains the battery pack.

Hybrid Development Centre