Poor man's hybrid electric system

Is it possible to rig up an ordinary alternator to a driveshaft/axle?

Another question - why are steel engine blocks so rare? Is there something about steel that makes it unsuitable for making engine blocks out of?

Question 2 first - iron is cheap, rigid and hard, (like me, or thats what I tell my wife)

Iron is an element. Steel is an concoction of iron and other stuff, like carbon, nickel, boron etc which give different characteristics to iron, like being less brittle, or being somewhat flexible, so it will flex a bit and return to its original shape instead of breaking.
Really, it comes down to cost and design parameters. Iron is ideal for engines, except for the weight and rust potential. Some parts, like certain crankshafts or connecting rods can be cast or forged steel, (most rods are forged steel which is, to over simplify things, casting under pressure).
If one was to go for the cost of a steel block, spend just a bit more and use aluminum which has more advantages.

Question #1, yes alternators can easily go on a driveshaft. Just make a bracket, bolt or weld it to the axle housing and fabricate a pully for the driveshaft. Some custom rodders do this to eliminate the alternator from under the hood, to give the car that "drag race only" look.

But, at 60 mph, a typical car with a 3:1 rear end ratio will spin the driveshaft at 2700 RPM. Therefore, at low speeds, the alternator will not be turning fast enough to generate an appreciable amount of energy - unless you used a really BIG driveshaft pully or used a reduction gear housing.

Finally, electric hybrids only reclaim about 25% of the lost kinetic enegy due to induction losses. . The coming new generation of hydraulic hybrids can reclaim up to 60%. Such hydraulic systems may be easily adaptable to existing RWD cars and trucks.

Question 2 first - iron is cheap, rigid and hard, (like me, or thats what I tell my wife)

Iron is an element. Steel is an concoction of iron and other stuff, like carbon, nickel, boron etc which give different characteristics to iron, like being less brittle, or being somewhat flexible, so it will flex a bit and return to its original shape instead of breaking.
Really, it comes down to cost and design parameters. Iron is ideal for engines, except for the weight and rust potential. Some parts, like certain crankshafts or connecting rods can be cast or forged steel, (most rods are forged steel which is, to over simplify things, casting under pressure).
If one was to go for the cost of a steel block, spend just a bit more and use aluminum which has more advantages.

Question #1, yes alternators can easily go on a driveshaft. Just make a bracket, bolt or weld it to the axle housing and fabricate a pully for the driveshaft. Some custom rodders do this to eliminate the alternator from under the hood, to give the car that "drag race only" look.

But, at 60 mph, a typical car with a 3:1 rear end ratio will spin the driveshaft at 2700 RPM. Therefore, at low speeds, the alternator will not be turning fast enough to generate an appreciable amount of energy - unless you used a really BIG driveshaft pully or used a reduction gear housing.

Finally, electric hybrids only reclaim about 25% of the lost kinetic enegy due to induction losses. . The coming new generation of hydraulic hybrids can reclaim up to 60%. Such hydraulic systems may be easily adaptable to existing RWD cars and trucks.

Nice post. I asked about steel since it seemed to me that because steel was stronger and tougher (i.e. cast iron is brittler) than iron but had roughly the same density, you could have a stronger, lighter block if you forged a steel ingot and machined it, just like how TFX does with its aluminum blocks for Top Fuel dragsters.

Of course, aluminum does have its advantages, but it's generally accepted that iron blocks hold up better.

also, Iron is the most abundant element on earths crust as well. aluminum not following far behing, problem is aluminum is harder to work with.