Neither ordinary (non plugin) hybrids (like the Prius) nor plug-in hybrids (like the Volt) suffer from "lurchy power-source switching" My own plug-in hybrid, the Zing! does not lurch at all, and drives like an electric car all the time. Only the noise alerts you to the fact that the engine is cycling when you go outside its electric only range.

"There's a certain tipping point with gimmicky techology that can put a car into the territory of feeling like a tinker-toy,"

What car were you thinking of that feels like a tinker toy?

The Ford Escape Hybrids that I drive for work have the "lurchy" problem. I think they are the 2008 models.

I worked with Hawaii electric recently on Electric and plug in hybrids. They could not dispatch a Leaf to north island because is an 80 mile round trip and they would have to delay their return while the leaf recharged. The Volt simply changes to gas operation on the longer trips.

Leaf is good for going to the grocery store but lacks the range to be a viable vehicle for a family car.Its fine if you only drive locally.Remember, recharging take hours!

suffer from "lurchy power-source switching"

Along these lines, I was pondering flywheel vs electric while driving my large pickup and wondering how one would drop down a couple cylinders on the diesel and couple in on-demand "insert second source here".

This required some means to couple all this power around the system, shunting unneeded power to the storage, and coupling it back into drive train as needed.

I can see that electricity would make all these conversions simpler, but is there a purely mechanical means that would work as well?

Replacement post was explanation enough - good answer - thanks!

Back in 1930, the Germans built a diesel-pneumatic locomotive which was more efficient, used less fuel for the same work, than a diesel-electric locomotive. Compressed air can be very efficient <<if you conserve heat>>, unlike the usual air-cooled compressors. The German loco probably used water injected into the compressor to cool it (see US Patent No. 5,832,728) and also used the diesel exhaust to further heat the compressed air. The air drove a conventional steam locomotive with the diesel engine and compressor replacing the steam boiler. (Between the Great Depression and WW-2, it's understandable that the railways continued with coal-fired steam locos) You could modify a diesel truck to use "a couple of cylinders" as an air compressor (modify the cam and manifolds). Store surplus compressed air (as from regenerative braking) and use it to boost power when needed (big hill). You can store about 1 kWhr per cubic foot of insulated storage. With enough tankage, you could run on air, with zero pollution, in town and recharge on the highway. There are various ways to use the air. With variable valve timing, etc., the same cylinders used to compress the air could be used to expand the air. Perhaps better, remove the conventional transmission and replace it with a "steam engine", an air motor, for pure "diesel-pneumatic" power transmission. Of course the air can be used to drive accessories, like winches and concrete mixers and such. If you cool the compressor by spraying water into the intake, the water need not be clean, drinkable. However, the water droplets in the air motor exhaust will have boiled (during compression, cooling the compressor) and condensed (during expansion, reheating the air) and will be distilled water. Filtered out of the exhaust, pure water is "free" and has some value, especially in places like Africa. The vehicle is "lo tech", using mechanical engineering techniques and ferrous metal components with a century of experience. (Ca. 1905, Chicago had air-powered street cars, no overhead wires needed. One might want to use composite air tanks. Ordinary SCUBA tanks will do for a vehicle) There are no batteries to recycle, no scarce or expensive or toxic materials, and the production cost would not be much different than for the conventional diesel truck. If you want to compete with a plug-in electric vehicle (think automotive X-prize), the storage tanks can be recharged very quickly from a stationary storage tank and compressor. The compressor could be driven with off-peak electric power or with green energy, like a wind turbine. A single gas (air) station could serve a fleet of vehicles (mail trucks, school busses) with less infrastructure cost than an electric fleet would need.

Nissan is certainly not the first mass - market car. REVA is available in India since 1995 and there are more than 4000 on road. In 2010 this comapny was acquired by Mahindras, the largest auto manufacturer in India for US $ 1.1 Billion. It is now available in 24 countries.

Seems like an ideal short commute car, that would eventually pay for its higher cost, or even save money. The up front price might stop me though. I would have to compare it to a Hyundai Accent, Elantra, or other small car. I hear that its price is going to go down, and that its range is going to go up though. Some day chargers will be available all over, but the charging time will have to be reduced too. Until then you will need another vehicle for long trips. Gasoline prices will probably steadily rise. Natural gas vehicles may become another option also. I have vehicles for six years, to wait and make my decision. I believe that it will be a strong contender against the hybrids for many people, and more so as time goes on. Mitsubishi has the MIEV and is coming out with a micro van that is all electric also.

I hear that its price is going to go down, and that its range is going to go up though.

This will no doubt occur in the future, but the price for the 2012 model is actually higer than for the 2011. MSRP is now $35,200.