Freightliner shows "EcoFred" Hybrid motorhome chassis

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Gary RV_Wizard

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Freightliner is showing the first ever fuel/electric hybrid motorhome chassis at the RVDA trade show in Louisville. It is called the EcoFred and is based on the popular and fuel efficient FRED diesel.  Fleetwood and Winnebago have built 36 foot motorhomes on the experimental chassis, but they are not for sale now or even soon. Informal tests show fuel mileage gains in the range of 7-19% vs diesel only and perhaps as much as 42% vs a gas engine coach. Details are sparse at this stage.

For the story(s) see:
http://www.tradingmarkets.com/.site/news/Stock%20News/2063997/

http://www.pe.com/wow/rvcamping/stories/wow_1203_RVWinnebagoHybrid.24d8a9b5.html

http://www.rvindustrynews.com/News/tabid/16941/ctl/ArticleView/mid/38805/articleId/2528/Freightliner-launches-ecoFRED-the-first-Class-A-hybrid-electric-chassis.aspx
 
Interesting.  I don't think it would reduce my carbon footprint by much though.  We're usually either on the highway or parked...  very small percentage of our travel time is spent in stop-and-go traffic where hybrids shine.
 
I am sure many folks don't know what "Hybrid Vehicle" means.

  It sounds so good and modern,....but, did you know that we are not talking about a 12 Volt system?  Think 200 Volts of battery power, more or less. They say the batteries are guaranteed for a long time.. where have I heard this before?

  Take a minute to read this link to get to know the system a bit better.

  Believe me, I am no expert on this, but have many questions about the application.

carson FL

 
re Hybrid batteries and longevity.
Toyota claim that they have NEVER replaced a Toyota hybrid battery under warranty.

I do have a question though, ---since diesels go a long(er) way on a gallon of fuel than gas models, but diesel fuel costs more per gallon, how does that work out costwise.??  I'm mainly thinking about cars here, and was interested by the post above which pointed out that hybrids do best in stop and go traffic.  I am surprised I haven't thought of that myself although I see how obvious it is now. Personally, I love these little diesels in cars, and mostly do the sort of rural driving at constant speeds which diesels like.  And I'm thinking of a diesel wagon to replace the Cherokees (2) that we have been driving for the last 16 years.

Rankjo
 
Toyota claim that they have NEVER replaced a Toyota hybrid battery under warranty.

  The sad fact may be that their batteries wear out 1 week after the warranty runs out.  ;) and then get your wallet out, big time.

carson FL



 
I notice Winny says 7%. Most hybrids exhibit their good mileage driving around town where the brake "charger is recapturing energy but mileage drops on the highway where engine has to run to supplement bateriries.

Since most of our RV driving is on the road I wonder what the fuel savings will be under actual conditions.
 
I'm waiting for the motorhome that travels off the solar panels on my roof.

Wendy
Pahrump, NV
 
rankjo said:
I do have a question though, ---since diesels go a long(er) way on a gallon of fuel than gas models, but diesel fuel costs more per gallon, how does that work out costwise.??  I'm mainly thinking about cars here, and was interested by the post above which pointed out that hybrids do best in stop and go traffic.  I am surprised I haven't thought of that myself although I see how obvious it is now. Personally, I love these little diesels in cars, and mostly do the sort of rural driving at constant speeds which diesels like.  And I'm thinking of a diesel wagon to replace the Cherokees (2) that we have been driving for the last 16 years.
Rankjo

I have an 02 VW Jetta TDI with 65,000 miles on it. I get 35 mpg in city driving and close to 50 mpg at interstate speed limits. The newer diesels which were designed to run on low sulphur fuel get much better than that and that's why diesels are so popular in Europe.

Now, my 6.0L F350 gets 25 mpg at 55 mph (when not towing) but the mileage drops off drastically with minor stopping and starting back up, idling at red lights, etc. to about an average of 15 mpg. Here's where a hybrid would help immensely. Diesel engine shuts off when idling more than 5 seconds and high torque electric gets you up towards speed using much less diesel fuel.
 
Over 60% of all cars in Europe run on Diesel engines.  My wife drives a Fiat Panda with a 1.1 liter diesel engine.  If you really hammer it you will only get 65ish mpg but go gently and this increases to about 75 mpg.  Perhaps one of these with a REALLY BIG turbo charger might be the way to go ;D
 
That's great fuel economy of the Fiat, although I'm not sure you'd get very far driving a large (heavy) motorhome with a 1.1 litre engine ;D

...you will only get 65ish mpg but go gently and this increases to about 75 mpg.

Comparing apples and apples, one needs to take into account the fact that an imperial gallon is 25% larger volume than a US gallon. That would bring your fuel consumption down to 52ish mpg and 60mpg respectively, but these are still numbers that most of us only dream about.
 
Heck, my generator is 0.8L - don't think a 1.1L diesel on the drive wheels would get me very far. Four of them might work (one at each corner) and still yield decent fuel economy, though.  Or perhaps a 4.0L generator powering big traction motors at each wheel (sort of like a diesel-electric locomotive). 
 
rankjo said:
I do have a question though, ---since diesels go a long(er) way on a gallon of fuel than gas models, but diesel fuel costs more per gallon, how does that work out costwise.?? 

Interesting question.  We bought an Itaska Navion IQ earlier this year.  It's a 24' 9" Class C built on a Dodge Sprinter frame, powered by a 3.0 L Mercedes-Benz diesel.

The fuel cost for us to drive at current local prices is about 15 cents a mile while the cost to drive a similarly sized new motor home with a gas engine would probably be about 0.5 cents higher, with diesel at $2.40 a gallon and gas at $1.40.

While we really liked almost everything about the IQ, I must admit that the decision was influenced by the difference in fuel economy between Dodge Sprinter based class C motor homes and motor homes based on other platforms, which all seemed to run in the 7 to 9 mpg range while the Sprinter based models get from 15 to as high as a 20 mpg according to some owners.

We're currently getting around 16 mpg, but hope the fuel economy improves as the engine continues to "break in."
 
I heard somewhere that Winnie said that mileage improved only on stop and start driving with this new chassis, and that on the "road", mileage would not improve any.  Jeff Cousins touches on this above.
 
Hybrids improve mpg only in stop and go driving, for two reasons: (1) The electric motor assist the fuel engine during acceleration, reducing fuel consumption and (2) regenerative braking during stops gives "free" battery charging.  Hilly terrain would be another area where a hybrid might improve mpg somewhat. Any road condition where acceleration is frequent.

Cruising on battery power is limited by the size of the battery bank, so the vehicle cannot run for very long on electric only (the fuel engine provides most of the battery charging). And most fuel engines are fairly efficient at highway cruise speeds - they don't consume a lot of power to overcome rolling  resistance. Wind resistance, however, is a major drag on Rvs and the main reason RVs use a lot of power/fuel.
 
A battery is only a storage device - it doesn't "create" power.   Any energy you take out of a hybrid's battery has to be replaced somehow - either from energy reclaimed from regenerative braking or energy supplied by the internal combustion engine.

Taking energy from the engine to replace the energy drawn from the battery will DEcrease it's fuel economy because it's working into more of a load.

That's why hybrids are great for stop and go driving.  You gain efficiency by being able to turn the main engine off instead of idling it while the vehicle is at rest (you get negative MPG while idling) and to a lesser extent by capturing energy from regenerative braking.

The downside for highway driving is you're transporting the weight of two engines (the normal gas/diesel engine) plus the weight of the electric motor and it's batteries.  More weight = more fuel needed to move it down the road.

I really question whether hybrid technology is effective for over the road vehicles that do mostly highway driving.
 
Lou Schneider said:
I really question whether hybrid technology is effective for over the road vehicles that do mostly highway driving.

It's not, which is why you don't see any over-the-road haul truck hybrids.  A promising technology is electric drive, but not as a hybrid.  Rather as RVRoamer pointed out, diesel-electric drive, similar to what locomotives use, is being tested.  Basically, you use a high-efficiency combustion engine running at peak efficiency to generate electricity only, then apply that electricity to charge a battery and to drive motors (I should note that locomotives don't have batteries and bleed off regenerated electricity from their traction motors using resistive heaters to get rid of the energy instead of storing it in a battery).  This is the concept being explored by the Chevy Volt and has the potential to yield relatively significant improvements in over the road efficiency as well as around-town improvements.

BTW, batteries in Hybrids have been proven to be one of the most reliable components of the drivetrain.  The average NiMH battery in today's hybrid will last as long as the chassis/drivetrain, or roughly 150,000 miles.  This is not theory, it is fact, and is supported by battery orders by Honda and Toyota hybrid owners, which is averaging less than 2 per 100 vehicles.  There is now over 10 years of real-life evidence to support that battery life is not an issue. 

That said, battery use in an over-the-road vehicle with an expected life of much more than 150,000 would obviously be quite different than in a passenger car and replacement would have to be considered in the life-cycle costs of any design.  LiON batteries  could be an improvement here but the technology is proving to be much more difficult to apply in real-world vehicles than GM, Toyota, Honda, or BMW expected, hence the delay in production Hybrids utilizing them.

The other benefit to electric drive vehicles is the potential to utilize "trolley assist" which involves using an outside power source for the vehicle (think of an overhead electric line, or an embedded electric rail in the highway) to avoid using the engine at all.
 
Lou Schneider said:
...  You gain efficiency by being able to turn the main engine off instead of idling it while the vehicle is at rest (you get negative MPG while idling) ...

By definition, you get zero MPG when you are idling and not moving. 
 

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