After unveiling a prototype ‘second generation’ diesel-electric FM9 hybrid truck last year, Volvo has confirmed that it will offer a full production-line hybrid based on the smaller-cabbed FE chassis in 2009. Biglorrryblog picked up this juicy tit-bit at the Swedish truck maker’s ‘CO²-free trucks seminar’ at Ghent in Belgium today, along with the news that long-distance hybrid drive-train packages for bigger trucks are also under development.
Although the current ‘parallel’ series FM hybrid demosntrator (that's it pictured above) has a nine-litre diesel engine in front of the electric motor, chief project engineer Christer Ehn reckons the additional torque provided by the hybrid’s secondary electric motor offers the potential to use a smaller primary diesel engine (or a klower rated engine) in the same equivalent gross weight ‘diesel-only’ chassis. This suggests (or at least it does to yours truly) that the FE hybrid could have a relatively modestly rated version of its seven-litre lump. Whilst understandably reluctant to spills all the beans, BLB did at least get Ehn to venture that a D9 diesel hybrid could be capable of operating up to 40-tonnes. Now that would be something…as the prototype is currently running at 26-tonnes.
The additional electric traction motor (seen mounted directly behind the D9 engine) provides enhanced torque and starting-off performance from rest before effectively handing over the work to the diesel engine when the road speed reaches 20km/h. As a result its acceleration from rest is very impressive offering excellent urban driveability. When the truck comes to a halt at lights or a junction the diesel engine is normally shut down, saving fuel. As soon as the driver puts his foot down on the throttle pedal it starts up again.
In addition to powering the hybrid’s electrical ancillaries, including air compressor, and steering pumps (which can be packaged anywhere on the chassis) the electric motor can also act as a generator, storing energy back in the battery pack (seen above) through regenerative braking of the truck. The whole process is managed by a clever ‘powertrain control’ computer while an I-Shift auto provides the perfect accompaniment to the hybrid driveline.
By using the extra oomph of the electric motor Volvo says it can cut the fuel consumption on the hybrid by as much as 30% in stop-start driving conditions. And with the conventional D9 engine (above) taking over at normal roadspeeds it retains a conventional long-distance capability. The D9 diesel can also be run on alternative fuels, like biodiesel as well. And by using the electric motor for pulling away the vehicle is quieter too.
While there’s nothing particularly new about hybrid trucks (indeed Volvo had a direct-drive ‘Series’ version based on the FL running in 1997) the advent of more efficient electric motors and in particular the latest nickel hydride battery technology means they have moved up Volvo’s green agenda. Biglorryblog is already angling for a drive of the Fm9 hybrid…I’ll let you know how I get on.