I had the idea of the battery dominant series hybrid June 2003. My idea was to use a turbine for the genset, but basically it was similar. People have been thinking about series hybrids for more than 100 years, nothing new, except the battery advances and high power semiconductors.

Patrick: I was thinking in terms of a medium sized battery pack (20-40 mile battery) with a medium sized stack for range extension. A smaller H2 tank would be cheaper than a big one. (you might have to tell the car how far you are planning to go so it can start the fuel cell early enough).

My personal favourite architecture would be a cheaper limited range (40 mile) BEV with the option to rent a range extender (in trunk or tailer) for that once a year long trip.

If GM would allow the user to specify the battery pack size/cost as well as the ICE size/cost, I'd be all over this. For those of us who don't especially want the "performance" aspect, have a model with 60-80 mile all electric range and a 25kw genset for the same cost.

I have had a similar concept in my head for a while now. Have an affordable vehicle, with a powerplant capable of totally being replaced as a unit. My idea was a cobra inspired commuter vehicle. When a newer powerplant becomes viable, swap in the new powerplant. Turn in old powerplant for a newer one. Could start as a ICE with a genset, evolve to a rechargeable battery pack, or evolve to a fuel cell stack, all in a convenient package.

Perhaps the more mechanical of us owners could have each powerplant in his garage, and easily swap powerplants as the upcoming immediate vehicle use changes. Fully battery only for weekly commutes, and the ICE/genset for longer trips or weekend use. Easily swapable, like changing batteries in a TV remote. I know its probably pie in the sky stuff.

Neil -

I don't know if fuel cells spoil with lack of use, but having one and not using it would be a very expensive hobby indeed. Moreover, the auto industry is receiving plenty of R&D money from the powers that be to develop fuel cells that use lots of hydrogen. A hybridized fuel cell would make more sense in engineering terms but advocating one in the US could cause you to miss out on the R&D funding gravy train.

In Japan, Honda's FCX was designed as an ultracap hybrid from the outset.

SJC -

you might want to look up Rosen Motors on Google. They advocated a series hybrid based on a single-stage microturbine-genset plus a gimball-mounted super-flywheel plus four in-wheel electric motors and power electronics to make it all play nice together. This was back in the mid-90s. The whole thing went nowhere, partly because potential investors got wind of crash safety concerns regarding the flywheel but mostly because the company insisted on retaining exclusive production rights for certain key components. The microturbine bit of the business still exists under the brand name Capstone.

Gas turbines operate at much lower pressures but much higher average temperatures than reciprocating engines do. Small turbines cannot be cooled internally, so their max. operating temp. is limited by the available materials to 1000-1100 degC. The net result is that thermodynamic efficiency is relatively poor, especially in part load. This is essentially why earlier attempts at turbine-driven cars by Chrysler in the US and Rover in the UK failed.

You could always run it "dry" and use all the gasoline and never fill it up until you plan to go on a long trip. I wouldn't do that during the winter (just in case you get stuck somewhere). You would also need a fuel pump not designed to use the fuel as a coolant (like most in tank fuel pumps are).

NBK-Boston: Most modern vehicles don't need their oil changed every 3 months unless you do some severe driving (towing, dusty conditions, etc.)

Neil, good call. GM is very smart to satisfy its customers with such flexible options. Hopefully we'll have all 3 options--when this thing--if this thing hits the market. It's also sort of built like your computer. One component goes bad, you switch it out for a new one. Or say you need an upgrade, based on your living situation that has changed--just buy one.

While this is a series hybrid, what is to stop them using the ICE to power the e-motor in parallel with the battery.
Then you just need a larger motor which should be no big deal.
The lack of a plug in option is a shame, but presumably one that would be easy to rectify.
I would be in favour of even smaller (15 - 30 mile) range plug in's if they had an ICE generator.
But in general, it sounds like a good solution or set of solutions - as long as they build it.

Oh sorry, i misunderstood the first part, however i agree what they did with just having the motor there to charge the battery, and nothing else. However i still believe that it is a plug-in.

re: sour gas and seized up genset:

Thanks for your replies all! If they do make the Volt then I would hope that either the genset is optional (I'll rent for a long trip) or the genset is accessible enough that I can decommission the engine and drain the tank between uses. (I did like the idea of halving the engine kick in every so often to keep it from clogging up)

It is in economical to develop a common basic electrical drive platform that can serve different models or fuel types. However, the E-Flex platform does not have to exclude the use of the more energy efficient and lower-cost Serial-Parallel PHEV (SPP)architecture. This SPP architecture will have a 8-10kwh battery and a 80kw motor instead of GM's planned 120kw motor and 16 kwh battery. The 53kw engine in the removable genset will supply on average about 30kw of direct torque power during acceleration to the 80kw motor to make up for the smaller size of the motor. At high speed, the SPP layout will have 138 kw total power at the wheel for autobahn passing power or police evasion maneuvering.

I envision an 80kw motor on the right side of the engine bay connected to the differential in typical fashion. Then, on the left side and adjacent to the 80kw motor is the "range-extending device" that can be either an ICE-genset, FC-genset, or more battery-power-inverter drop-in package.

For use with an ICE-genset, just drop the genset into a rail or groove on the left side of the car's engine bay, with the 80kw motor sits opposite to the genset, and the axis of the motor to line up with the rotational axis of the engine of the genset. A hydraulic or mechanical mechanism is used to move a clutch plate (splined to the engine shaft) a short distance from the engine to the clutch plate of the motor for reversible torque coupling of the engine to the motor. At rest, the engine is not coupled to the motor,so the entire genset can be removed. No gear whatsoever is needed to connect the engine to the motor, just direct drive via clutch plates.

If a removable fuelcell genset is used, it would be of 30kw max power rating and has a 30kw motor built in to the genset to supplement the power of the 80kw motor, for a total of 110kw maximum power. When this genset is dropped into the grove in the engine bay and secured, then the torque of the 30kw motor will be locked via a manual mechanism to the 80kw motor of the engine to give a total of 110 kw power output.
A turbine engine genset is not recommended due to the poor efficiency of the microturbine.

If a pure BEV layout is used, then the drop-in range-extender on the left consists merely of more battery, plus an optional 30kw motor for sporty performance, and more power inverter to control additional motor power. Same coupling mechanism can be used to couple the 30kw motor to the 80kw motor as when the FC genset is used. Perhaps another 8kwh battery will fit within the drop-in space on the left of the engine bay, for total of 16-18 kwh capacity and a range of 40-50 miles, for those desiring to use this vehicle strictly for fixed-distance predictable daily commute. If charged twice daily, a commute range of 80 miles is possible with enough reserve power to deal with cold weather when battery capacity will drop. Then, before a long-distance trip, the vehicle can stop by a dealer and have the battery range-extender package swapped for a ICE genset. This ICE genset installation also comes with a 5-gallon gasoline or diesel tank located on the right side of the car's engine bay, above the 80kw electric drive motor. 5 gallons at 60-70 mpg is good for 300-350 miles before the next fill-up. This tank may be made of flexible but rupture-proof material similar to those used in race cars, or strong carbon fiber re-enforcement that will not rupture in a survivable frontal collison.

Beautiful vision of the future, ain't it? Can't wait until this thing will come out!

Hi All,

Eflex is obvious and elegant. I am glad it finally made it through the corporate engineering committees! Its not ideal for traditional vehicle engine technology, which is oversized to deal with the poor low rpm performance of these engines. A series-parallel system like the Prius is better for that. But that assumes we will always be using engines that owe their heritage to being shaft coupled to the car wheels. With an Eflex, other engine options are available.

I think one reason it has not come out sooner is that NiMH Batteries patents are reportedly now controlled by a company unfriendly to fuel savings. Lithium batteries have made it out of the lab, but not through the vehicle manufacturer testing. Also, the Plug-in imperative makes the inefficiency of the energy conversions in a series Hybrid less of an impact, since it runs 80 % of the time on Plug-in energy.

Think about an EV1, with a stretched body, with a prime-mover bay. At sale time you take your pick of prime-movers to plug into the bay . Tubogenerator (4 inch ID) that runs continously (and on ANYTHING THAT IS FLUID AND BURNS), small turbo diesel, fuel cell, Miller cycle gas engine for the really cold climates or urban polution reduction zones (those will come, especially in China!), large charging power supply, or even a lithium air energy module (non rechargable but massive energy density).

The adaptability of this concept is its great strength. With a turbo generator, one might even pull the thing, and save the momentum during the summer driving season, and plug it back in when the temps get down below freezing, or for that long range trip. Or another idea, since these are expensive, would be just rent one when you need it, and run on battery the rest of the time.