Diesel-electric trucks?

Question

Modern locomotives use diesel-electric motors to haul freight across the country. Does anyone know why we don't use diesel-electric motors in our big semi's?

Answer 1

Weight and size.,you cannot make a electric motor produce power to move a load in a vehicle that size.Now Huge strip mine trucks are diesel electric.

Most hybrid systems use the electric motor assist the fueled engine.As making room for electronics, requires smaller engines.

Answer 2

we should be making hybrids.

think of all the charging you could get braking 44 tonnes! and carrying the batteries should be no prob., trucks regularly have 2x500l tanks. andother 1/2 a ton here or there doesnt make a lot of difference.

Answer 3

the biggest problem is weight. in a locomotive you dont have the weight limitations that an over the road truck has. the DOT limits the maximum weight of the average 18 wheeler to 80,000lbs total weight, without an over size permit, where as most freight trains run something on the order of better than 2300 tons average load. when you figure the weight of the diesel engine, the generator, and the electric motors, along with the dynamic braking system, and the other things that are needed for the system, you dont have enough room under teh weight cap to make the diesel electric truck a money making deal, since loads would be severely limited.

Answer 4

Diesel-electric powertrains are not as efficient as direct drive via a gearbox.  The reason locomotives use a diesel-electric powertrain is because of the operating environment and the amount of torque required to accelerate the load they are hauling.  Because they are using steel wheels on steel rail, a normal gearbox would not be able to withstand the shock and vibrations from the tracks but electric motors, with few moving parts, can handle it much better.  Also, electric motors provide maximum torque at 0 RPM where it is most needed.

Answer 5

Rather than using diesel electric to power 18 wheelers, why not use modern flash-boiler steam instead? It's the same principle but steam offers a number of advantages.

Modern steam engines could be made lighter than diesel engines. Fewer moving parts, no transmission required. Practically silent when running.

Flash technology would allow a head of steam to be raised in a few minutes and modern condensers would recover most of the water, (if not 100%), and you could use a variety of energy sources to keep the steam up.

Steam is probably impractical for passenger cars, but it would be ideal for semis and busses.