Hybrid Quadracycles: Series Hybrid

[paultrafalgar]

Hybrid Quadracycles: Series Hybrid

In the latest issue of AtoB magazine (no.73 Aug/Sept 2009) on page7 Andreas Fuchs shows a picture of the series hybrid quadracycle that he developed with Jakob Gilgen. He mentions that, unfortuneately, that vehicle never went into production in Switzerland but says that if a UK company were interested in building something like this he would certainly be willing to act as consultant. For more details see: http://www.hupi.org/HPeJ/0015/0015.html
Come on all you eco-friendly investors out there!

 

[Takemehome]

Did I miss something in the reading ?

You transform mechanical energy (pedal) in electricity that is then transformed back in mechanical energy by the motor ?
If I remember well, you waste energy each time you transform from one form to the other.
And when the electric system fails, you can't pedal your way back home like a conventional e-bike ?

 

[paultrafalgar]

Takemehome, the link I gave has a paragraph headed efficiency which deals with this:
Efficiency

The SH drive system does not compare with a purely mechanical chain drive e.g. of a racing bike but was not made to replace such drives, but rather to replace mechanically complex hybrid drive systems.

The first working models of the SH drive were equipped with brushed generators with peak efficiencies of between 55 and 70% and with brushed motors with about 80% peak efficiency. However we were astonished that we rode about as long and far as typical PH e-bikes. This was confirmed when Chapelle and collegues measured efficiencies of PH e-bikes of between 55% and 95%. Thus it is possible to build SH vehicles with better efficiencies than the poorer PH bikes.

So far we only discussed “peak” efficiency. If the average efficiency during the whole trip is considered, the efficiency of SHs compared to that of PHs starts to look interesting.
In urban traffic a vehicle is on constant speed only for a minor part of the travel time. Therefore the advantage of high peak efficiency at one operating point of a parallel PH remains advantageous only if the efficiency at other operating points is also good and/or if the gears are used effectively to stay in the optimal region.

People not trained in optimal operation of traditional bicycle gears often pedal off their peak efficiency because humans have a quite narrow peak of high efficiency at some power levels.
A major advantage of the SH is that the system can react more quickly than mechanical gears. The efficiency of the system can be maximized electronically at every moment. The human being can be optimally loaded: the "load-leveling" capability of SH's is very advantageous from a physiological point of view. This was borne out by the author and colleagues and by Daniel Couque (who constantly pedals a generator while manually operating the throttle of the electric motor of his velomobile). The experiences are too few to draw final conclusions yet, but it cannot be easily discounted that the physiological advantages of a SH could over-compensate the disadvantage of peak efficiency of a SH compared to a PH.
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On your second point, yes, as there is not mechanical link only electrical, you can't get home if the generator breaks, but neither can you if you chain breaks. :wink:

 

[spinningmagnets]

Paultrafalgar, I am a fan of the series-hybrid plug-in EV. A pure series-hybrid where an engine generates electricity that is fed to a drive motor (Porsche EV from year 1900) has many conversion losses, so most modern hybrids are a parallel-hybrid system. This means when the ICE engine is helping drive the vehicle, it is directly driving the mechanical transaxle.

A pure series-hybrid simplifies some aspects of construction for the home builder, but in my opinion the place where a series-hybrid really shines in the plug-in hybrid, where the battery is enlarged enough to provide electric-only capacity during the vast majority of trips. If the engine is rarely used, and even then only as a range-extender, ultimate efficiency is less of a concern.

Imagine you buy or convert an EV that uses 200-Volts. After a couple years, you occasionally want longer range about once a month. You can put a 220V generator on a short trailer. Many generators are available that have either two 110V oulets, or you can switch to a single 220V outlet. They are available in many different sizes, and can run off of gasoline or diesel/bio-diesel.

The car doesn't care what brand or size the engine is as long as the electricity coming out of the cable is the right voltage. And for the majority of trips, you can leave the weight of the ICE engine/gen at home. Plus, it doesn't hurt to have a mobile 110/220V power trailer as a back-up for your home.

 

[jag]

Diesel-electric locomotives are a kind of series hybrid vehicles. A Diesel engine drives a generator or alternator. Then wheel mounted electric motors provide the propulsion. http://en.wikipedia.org/wiki/Diesel_locomotive

I was curious what the efficiency for a Diesel-electric locomotive is. Didn't find it on the web. Anyone knows?