4 ms·
This is not necessarily true, but it is often true for consumer car models that are already designed in quite complex ways around driveshaft power, with abundan
by mapt 2y ago
This is not necessarily true, but it is often true for consumer car models that are already designed in quite complex ways around driveshaft power, with abundant compromises and costs. It's never "directly" transferred; Not even close. Something like an automatic transmission is a miracle of engineering perspicacity over the decades. If you're going to spend thousands of dollars including one based on driveshafts, then electric conversion looks a bit silly.
In locomotives, some ships, and now tanks they're replacing the whole drivetrain with copper wire driven by an ICE alternator. Even with zero energy storage this permits a dramatic simplification of the vehicle, and often we're more than willing to pay the cost of mechanical->electric->mechanical conversion efficiency in exchange for losing a bunch of cams, gears, and 90 degree joints that each eat a little energy, take up space in the design, and weigh a significant amount. And it is very often the case that adding energy storage (a very simply bolt-on + software changes) permits dramatically reducing the size of the engine needed.
- sandworm101 2y agoSmall engines are very different than big. They have very different needs re weight and complexity. A locomotive drive engine is basically mated to its power generating engine, moving in lockstep. Everything gets more complicated when one also wants to charge a battery. (Fyi, many locomotives have huge banks of resisters specifically for dumping energy into heat, which is not an option for cars.) Separating charge and power deliver requires two motors, a power-harvesting generator connected to the combustion engine and a separate drive motor. Those would need to be electrically separated since they would be always turning at different rates. That means totally separate charge and discharge circuitry, possibly even separate battery banks. Harvesting from the wheels might even require a third circuit to simultaneously charge from two sources. And the drive motor equipment would have to be sized large enough to cover the entire rated power output. Secondly, such a battery-in-line arrangement may create a battery-essential system whereby if the battery failed/discharged/overheated, the vehicle would just stop despite still having a working combustion engines. (The power direct from the generator may not be compatible with the drive motor.) Modern hybrids bypass all these problems by routing the IC engine to the wheels. The electrical system is then a single motor and an additional sprocket in the transmission. Power is then added or removed through a single motor and associated circuitry with no need to generate and provide electrical power simultaneously (F1 cars used to work like this). Add an extra differential, aka a "hybrid transmission", and you can run either motor alone or together (as in the Prius).
- lmz 2y agoDoesn't the Prius also have two motor/generators instead of a single motor?
- sandworm101 2y agoIt had a motor and also used the IC starter motor to harvest energy, but not to provide power.