Opel, Bosch, University of Stuttgart and FKFS Develop CNG Mild Hybrid Astra

Opel Astra Caravan Turbo CNG - Hybrid Prototype

STUTTGART : March 27, 2009 - Opel, the University of Stuttgart’s Institute for Combustion Engines and Motor Vehicles, Bosch and the Research Institute for Motor Vehicles and Vehicle Engines Stuttgart (FKFS) have developed a mild-hybrid CNG-electric version of the Opel Astra Caravan.


The CNG hybrid Astra, developed in a two-year project, uses a 1-liter, 3-cylinder turbocharged CNG engine that produces 97 hp (72 kW) and 160 Nm (118 lb-ft) of torque. A 35 kW Bosch electric motor that develops 160 Nm of torque as well provides traction support. The Caravan emits 90 g CO₂/km.

System architecture for the CNG hybrid

The electric machine also functions as a generator to recharge the General Motors-developed NiMH battery pack. The latter has a capacity of 7 Ah at a rated voltage of 255 V.

The vehicle features a forward-looking hybrid coordinator, GPS-based system that determines the road type over the next two kilometers and adjusts hybrid system control accordingly—e.g., preparing for gradients, curves, stops, changes in speed limits and so on.

[Source : Green Car Congress]