[NeilBlanchard]

B.O.T.

Despite assurances from people like Chelsea Sexton, I'm very concerned that the very conservative execution of the Volt will be it's undoing. It uses an engine that is at least 2X too big for the job it is needed for -- it is exactly the same engine that will be used in the ICE-only Cruze; which is a nearly identically sized car. (see below)

Doing this almost completely negates the efficiency that is gained by being a serial hybrid!

The (much) heavier 1.4L engine has to be dragged around all the time by the electric drive motor, and so reduces the battery's range, and the battery has to be bigger than it otherwise would be -- so it's own weight is increased, which in turn decreases the range...

Almost nothing in the basic chassis stands out as helping the car be more efficient: they are using bog-standard steel with no innovation to increase strength while saving weight, as far as I know. Add to this the "FAT" seats, etc., and you get a fairly big and heavy car that has a small interior.

They have taken a decently aerodynamic car, removed the transmission -- and replaced it with a large battery and an electric motor. So, they end up with a slightly more efficient car that is a lot heavier. The cost and weight savings of the transmission is swamped by the increased cost and weight of the battery and electric motor and all the control systems...

Why would the Volt need 100HP? The same 1.4L engine will power the Cruze, and even with a transmission, you need that size of an engine to get the power in off-peak conditions.

The whole point of a serial hybrid, like the Volt -- is to use the engine at it's peak efficiency to charge the battery. For example, the Aptera 2h (1,700 pounds and extremely aerodynamic with a Cd of 0.15) needs an approximately 15HP engine to generate enough power to "keep ahead" of the rate the car can use the electrical power.

So, if the Volt weighs ~2X as much and has a Cd of ~0.25, do you think it could get by with a 50HP engine? Or maybe a 35HP engine? I think that it could! Especially, since such and engine would save 400-500 pounds (from both the smaller engine, cooling system, and the smaller required fuel tank). The chassis and suspension and brakes could be proportionally lightened then, too.

[Edit: the prototype Mini serial hybrid mentions that the charging ICE is 1/10th the weight of the original 4-cylinder. I'm reading that the GM engine is an aluminum block, so I'll revise my guesstimate down to 250-350 pound savings, including the smaller cooling system, and smaller fuel tank, and smaller everything else (suspension, brakes, etc).

They originally planned a 1L 3-cylinder turbo for the Volt -- which is still too big in my opinion.

Oh and the Cruze has a turbo-charged version of the 1.4L rated at 140HP.]

Some of that weight savings could be used to increase the size of the battery pack, which would increase the EV range, and provide a larger cushion of time to get the charging done.

The seats (and probably other things) could be made less "fat" in the Volt as well, and I'll bet that more weight could be saved, and the interior space could be made larger and more useful.