MVO Articles
Hybrid Heaven?
Has Faun really cracked the hybrid issue with an RCV capable of reducing noise and carbon footprint levels, while being able to operate in the real world? Malcolm Bates tries out the prototype in the German city of Aachen
The office phone rang. Would I like an exclusive opportunity to drive the RCV of the future? The answer was obvious - yes, I would. "We will arrange it," confirmed Claudia Schaue, the highly-efficient PR manager at Faun HQ in Osterholz, Germany.
In the blink of an eye, here I am on the ground in Bonn airport, facing a dash down the autobahn to Aachen. As we arrive at the local city council depot, the prototype is parked up, ready and waiting. Hang on, it looks suspiciously like an ordinary Faun Rotopress - a design that was first unveiled in the 1930s. There must be some mistake. After all, how can a design that is 80 years old possibly claim the moniker "dustcart of the future"? I'm confused.com [Hey! No free ads, not even if it does mean cheap insurance on your personal fleet Malcolm - ed] and a bit disappointed.
"So, here is our new hybrid prototype," announces Georg Sandkuhler, Faun's head of R&D and my host. "As you can see, we based it on the existing Rotopress, but don't be disappointed that it is not futuristic in appearance (he must have read my mind!) because the new technology is under the skin." Hmmm. We'll see about that. Just how advanced can you make a Rotopress? Nuclear fusion power? Carbon fibre construction? Before we start, Georg suggests a quick introduction to the key features and, straight away, I can't help noticing he's full of enthusiasm… in a refreshingly un-German kind of way!
"We'll start with the hybrid drive system," he suggests. "While Faun has no wish to be a chassis manufacturer, it was quite clear when we started this project that the heavy truck chassis manufacturers had no incentive to design and market a transmission exclusive for garbage collection, as the demands on this kind of operation are tough and the market is small. As it is our business to meet the needs of our customers - and as the hybrid transmission also had to work in conjunction with the compaction system - we decided to take a lead." I like Georg already, he has this wonderfully understated approach to the job, yet it's obvious he knows his stuff. His team also has the resources to do the job - Faun is after all, one of the largest RCV manufacturers in Europe and is now back in profit. Besides, no single nation is better at long-term planning than Germany; during the very week of my visit it was announced that German holidaymakers can now reserve poolside sun loungers online without having to rush down before breakfast to drape their towels over their chosen perch! That's the "Germans and forward planning" issue nailed then.
But I'm still not sure how the Faun hybrid system works exactly, as unlike existing stop/start hybrids, or the recently introduced Volvo/Geesink Norba system, the Faun approach is to "integrate" the power requirements of the chassis and the body/hopper, and that's much harder to do than merely adding a battery pack to power existing hydraulic components. I say "merely" as if that in itself is easy, which quite clearly it isn't, otherwise every OEM would have a hybrid system ready for production… and they do not.
Integrated Solution
If we're talking "integration" of power system demands, there's only one way to go, according to Georg, and that's not some mix of hydraulic and battery electric power. The way to go is entirely electric. That's right. Do away with all the hydraulics completely and you not only save weight - both oil and the tanks to keep it in are heavy - you save a source of (oil) pollution, heat and just as significantly, you save a major source of power loss. "But, but…," I interject, "surely the best driveline system for multiple stop/start work is a diesel engine with a hydrostatic transmission?"
"We started with that principle, but we soon discovered that it was not practical for us as a body supplier to undertake the driveline modifications, as this would have implications in terms of chassis warranty, as well as the need to take large numbers of vehicles into our shop for the hydrostatic conversion," Georg explains, a point that engineers at Scarab Sweepers will be able to endorse. It can be done, but it takes time. And with each different make and model of truck chassis comes an extra layer of red tape and therefore added cost!
The Faun solution? Leave the existing truck driveline alone. Do away with the hydraulics completely. And, instead, mount a small auxiliary (or "donkey") engine on the side of the chassis rails, where CNG gas bottles or rival hybrid drives locate their battery packs, then couple that engine to an electricity generator - a rather impressive generator that not only has enough power to take care of all the demands made on it by the compaction system and bin-lifters but, at the same time, has more than enough "grunt" to provide an electric drive mode that is not dependent on the juice remaining in a battery pack. The prototype uses a 30kW Deutz diesel (as might be used to power a dumper) but thanks to detailed systems analysis by a team at IKA Institute, Aachen University (world famous in hybrid drive research), a smaller, lighter VW diesel engine will be used in the production batch. I'm told the power needed to power the truck at up to 20kph (the collection speed) is only 8kW.
Hang on a minute, let's get this straight - unlike the Geesink Norba/Volvo approach that currently uses two independently-charged battery packs, the Faun system uses two diesel engines? This is an advance? How is this in any way ecologically better than a conventional single diesel engined vehicle?
Luckily my puzzled look was spotted by Georg. The key to the Faun hybrid system, he tells me, is a little component called a "supercap". It gives the same effect as a mechanical accumulator and allows energy to be stored - from regenerative braking forces - and then released on demand. I don't have all the figures to hand - although, as you might expect from having university input, they have reams of them - but a supercap gives as much, if not more, "oomph" than you'd expect from a battery pack (175kW is available to move the RCV away from a standstill), without ever going flat because the donkey engine is there to provide additional recharging on demand. This removes any operational concern that an especially tough shift might leave an RCV stranded. But, wait, there's more…
Just Like Any Other?
In normal "transit mode" between the depot and the start of the collection round, the normal diesel engine and Allison automatic gearbox is used, so the Faun hybrid - in this case based on a Mercedes Econic 6x2 rear steer - drives like any existing RCV. This prototype has hydraulic power steering but, on the next batch of 20 pre-production demonstrators, the existing chassis hydraulics will also be replaced by electric alternatives. But as the chassis drivetrain no longer needs to provide any hydraulic power for the compaction, or bin-lifter, or for stop/start work, Faun engineers suggest that a lower horsepower truck engine could then be specified, with gearing matched to most economical running, thus saving weight, cost and fuel. Around 30 percent in terms of fuel consumption overall (yes, even with two diesel engines!) and an equally impressive reduction in CO2 levels, I'm told. Extra cost? Well, unfortunately, yes. But a large chunk of the estimated £45 000 additional cost over a conventional RCV could be won back within five years through efficiency savings and reduced consumption… and reduced brake wear costs. Plus, as a sweetener, all dual power hybrids will come with a full three-year Faun warranty,
But, for collection operations (and this is the clever bit), the on-board computer is used to work out the optimum regenerative braking distance and speed of retardation to provide the optimum amount of energy to provide the "boost" to the vehicle when it's time to pull away from a stop. Clever? It sounds like the nearest thing we'll ever get to perpetual motion and I'm just itching to try it. Georg switches a second ignition key from "diesel transit mode" to "hybrid electric mode" and, with the main Mercedes diesel engine shut down, lots of lights flicker on the dash before the Deutz unit on the side of the chassis fires up with a muffled rumble. Then one of two flat screens come to life to show the status of the system.
"Now I'll show you something," Georg exclaims like a kid who just got a new trainset for Christmas. He pushes the "forward-neutral-reverse" lever into forward and floors the accelerator pedal. Wow. Think of the fast forward control on your video at home, it's… well, it's obviously not as fast as that, but it's still much better than I was expecting and seemed all the more so, when, with the supercaps fully charged, the auxiliary engine switched itself off. It all happens with little more than a milkfloat-like hum.
Several more demonstrations later and it's time to drag Georg out of the driver's seat. It's my turn. First thing to note is that with the Econic in "hybrid mode" there is no need to either touch the service brakes, or even apply the handbrake. The system has a "hold" and "anti-runback" function, which should be a major contributor to reducing driver fatigue. "Okay, give it maximum acceleration," urges Georg at the outer reaches of the Aachen city council depot yard. Now fair enough, we're still empty at this stage, but the rate of pick-up is impressive and entirely controllable. I suggest that it's still not as fast as my normal diesel/auto "launch" technique at busy intersections - building up revs while standing on the brake, then letting it go. "I think you'll find the hybrid is faster," says Georg with conviction. I try it, he times it. He is right.
Electric Compaction
So, with the advantages of the hybrid driveline looking positive, let's move on to the compaction part of the package, because this is clever stuff. We need to start with a basic understanding of physics. Don't ask me for formulae here, just take my word for it, a rotary action is better than a linear force. Think of the forces at work in an ordinary petrol or diesel engine - the "up and down" bit (the piston and conrods) has to be converted into a "rotary" force in order to turn the wheels. The hard part is making that happen without unacceptable power losses.
Now think about most of the designs of an RCV. They crush waste and recyclable materials by a linear action - hydraulic rams that go up and down, or in and out. The same motion applies to the ejector plate and it all takes a lot of power to make it work. And that produces shock loading, noise and vibration.
The Rotopress, however, is… rotary. The body is the compaction system. It has fixed tines inside and only requires enough power to keep it slowly rotating while being loaded. Not only that but, when it's empty or even just part-loaded, it requires considerably less power than it does towards the end of the loading cycle. In contrast, the design of a conventional RCV demands full power right from the start because it has to force the waste material into the ejector plate under pressure before the plate is forced back. In terms of energy consumption, this is a far more complex issue than we have space for here but, take it from me, "rotary" is less wasteful.
Anything else to consider? I should say so. There will always be noise involved with picking up waste, of course, but the conventional Rotopress is already quiet. By removing the need for a hydraulic pump - and the revs needed on a 280hp truck engine to create that power - the official overall maximum noise envelope of 90dB(A) can be reduced. In practice, at 54dB(A), the hybrid electric system itself is almost totally silent, so the noise has a better "quality" to it.
But hang on, surely the bin-lifters are hydraulic and therefore create noise? Nope! In fact, the idea for this advanced prototype could have almost started with the back end because, while other refuse compaction vehicle manufacturers have only grudgingly agreed to fit the Ecoprocess electric bin-lifters to meet ecologically-minded customer's requirements, Faun took a close look at it, saw the advantages and decided to make this unit an integral part of the new hybrid programme. "I am very impressed by both the product and the people at Ecoprocess," Georg explains. "Because the Rotopress has a higher than normal loading rave, we asked their designers to produce a special configuration for us. They did so in just a few weeks and it works fine."
So what does Georg know about RCV design? C'mon, he's the man! As a young designer he came up with the best solution for one or two-man wheeled bin collections - what became the Faun "MSTS" product - a front-loading, demountable and potentially multi-modal refuse container system that still hasn't been equalled for its logic. Unfortunately, "political" factors - coupled to it needing a rather special low cab/short wheelbase truck chassis - prevented it being developed to its full potential. But, as an innovative design, it's right up there.
Action in Aachen
So, having established Georg's credentials, let's put his latest project to the test. We're going downtown to mix it with the traffic - and the famous Aachen triple-unit articulated bendi-buses - in an effort to see how the hybrid works in real life. Unfortunately, due to a labour dispute over some other issue, I've not got a crew with me as planned. But, for effect, we meet up with a conventional RCV working for Aachenerstadbetrieb (Aachen City Council works department) and follow them on a typical round. I soon discover this is much too slow, so I find a neighbourhood with the bins out, but where the regular crew haven't arrived yet, so we can test the hybrid drive more fully. It really does work and driver fatigue is reduced dramatically as there is always plenty of power in hand when pulling out into traffic, for example.
One thing does make me chuckle though; in health and safety conscious Germany, it's quite normal for collection crews to hang on to the rear steps, as the vehicle moves from one pick-up to the next, while in fellow EU member state, Great Britain, it's a sackable offence! So, I should stress at this point, absolutely no Germans were harmed in the production of this article!
What's next for this interesting project? Get it over to the UK, of course. Trials in Aachen are scheduled for 12 months but Simon Hyde at CIWM Business Club member, Zoeller Faun, is looking into it as you read this. Stay tuned for more news…
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