Opel Astra Diesel Hybrid Concept Demonstrates Easy Scalability of Innovative Two-Mode Full Hybrid System

Detroit.  The Opel Astra diesel front-wheel drive concept vehicle, equipped with a two-mode full hybrid and the 1.7-liter CDTI engine, delivers up to 25 percent improved fuel economy while maintaining fun-to-drive performance.

The concept vehicle, which celebrates its world premiere at the North American International Auto Show in Detroit (January 15 – 23, 2005), is based on the production-version Opel Astra GTC and was built at GM’s European International Technical Development Center in RĎ‹sselsheim, Germany.

The world’s first two-mode full hybrid system, to be co-developed by GM and DaimlerChrysler, is based on the multi-patented hybrid-electric diesel technology pioneered by GM on 335 urban transit buses currently in use throughout North America. 

The unique architecture can be scaled to fit FWD, RWD and AWD vehicles and adapted to both gasoline and diesel engines. Two electronically controlled electric motors act on a series of gears to create an infinitely variable drive system. The system fits within the space of a conventional automatic transmission. A battery pack supplies power to the electric motors and also allows for full-electric propulsion.

As a packaging study, the Astra Diesel Hybrid demonstrates how hybrid components can be integrated into a compact car without compromising passenger comfort and the vehicle’s utility. The nickel-metal-hydride battery pack is located in the spare tire well, along with cooling fans. The battery was developed with specialist Varta.

“We decided to use a diesel-powered car as a starting point because in the mid-term, we don’t see a demand for gasoline hybrids in Europe,” said Hans H. Demant, GM’s European engineering vice president and Opel’s managing director. “Our state-of-the-art CDTI engines already deliver impressive dynamics and low fuel consumption. The Astra concept demonstrates that fuel efficiency and vehicle dynamics can be significantly improved by hybrid technology.”

The Astra Diesel Hybrid is propelled by a powerful 92-kw (125-horsepower) 1.7-liter CDTI engine with a maintenance-free particulate filter and by two electric motors, rated at 30 kw and 40 kw, respectively. Depending on the driving conditions, the electric motors will deliver additional power for the diesel engine or will propel the Astra with full electric power. A sophisticated controller determines the propulsion mode. The electric motors boost the already strong performance of the turbo-diesel engine, delivering a feeling of performance that would otherwise be achieved only with a larger-displacement engine. Acceleration performance of less than 8 seconds from 0-100 kph (62 mph) is expected with the Astra Diesel Hybrid concept.

With fuel consumption below 4-liters/100km (MVEG mix), the Astra Diesel Hybrid is projected to be 25 percent more fuel-efficient than comparable diesel models. This is achieved through the hybrid system’s operating parameters, which include full engine stop at idle and full electric propulsion at launch. The electric motors also are used for deceleration, where kinetic energy is recuperated and stored in the battery. During braking and coasting, the electric motors work as generators to charge the battery pack.

As with other vehicles using the two-mode full hybrid technology, the Astra Diesel Hybrid incorporates two separate on-board electrical systems. The drive system uses a high-voltage system, while the other converts electricity to operate a 12-volt system that powers safety and convenience items such as the lights, HVAC and the audio system.

From the outside, the Astra Diesel Hybrid, with its unique panorama windscreen, doesn’t look much different from a production-version Astra GTC. Inside, however, the tachometer in the gauge cluster has been replaced by instruments that provide feedback on the operation of the hybrid propulsion system, such as traction provided by the electric motors, traction from the diesel engine, or both.

Another gauge displays the battery’s charge level. Also, a video animation in the graphic information display located in the center console depicts the current propulsion state of the vehicle when it’s driving.

The two-mode full hybrid technology can provide a significant reduction in fuel consumption helping to meet ever-stringent carbon-dioxide emission targets. Its scalability enables the technology to be applied to markets around the world.

TECHNICAL DATA: Opel Astra Diesel Hybrid Concept Vehicle

Vehicle type: front-wheel-drive, five-passenger concept vehicle based on the Opel Astra GTC

Dimensions (mm / in):   length: 4290 / 169

                                   width: 1729 / 68

                                   height: 1433 / 56.4

Diesel engine:   1.7L CDTI with 92-kw/125-hp and 280-Nm/206 lb-ft of torque; with maintenance-free particulate filter

Electric motors: two: 30-kw and 40-kw; integrated within transmission case

Two-mode Full Hybrid:  electronically controlled electric variable with mechanical lock-up

Battery:                         type: 1.3-kw NiMH (Varta)

weight: 35 kg / 77 lb

location: spare tire compartment

Performance: 0-100 kph / 62 mph = less than 8 seconds

Fuel consumption: less than 4 liter diesel / 100 km in the MVEG cycle