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Old 01-09-2018, 04:13 PM   #147 (permalink)
Ecky
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I'm not annoyed in the least.

I'll try my best to explain:

Unless you plug your car in, the source of all energy in your car is ultimately from gasoline. Sometimes you can scavenge some of it back by capturing it when you slow down, and this is one way hybrids save fuel.

Let's say you want to run the front hub motors all the time to produce power, and you want to create that power from motors attached to the rear wheels (either hubs or altermotor). If you want to send 5HP to the front motors, you'll have to take away ~6HP from the rear. Since all power ultimately comes from gasoline, your gas engine actually has to work harder, burning more fuel.

Or in other words, let's say you need 20HP to overcome air resistance and move down the highway. With the gas engine alone, you would burn enough fuel to make 20HP and cruise along. If you want instead to send 5HP to the front wheels for full-time AWD, you would have to burn 21HP worth of fuel, because although the front is now subtracting 5HP from what the gas motor has to make, the rear is adding 6HP, and that extra has to come from gasoline.

Normally hybrids try to only use the energy they can capture for free. For instance, when you go down a hill, it saves all of that energy up to be used to go up the next one. Without the hybrid system, you'd lose that energy to your brakes, and would have to burn more gasoline to get up the other side. The same applies to stopping at a traffic light; when you slow down, it saves up your momentum in the battery, and then uses it to get you going again, so the gas engine doesn't have to. You also get the added benefit of a ton of extra torque when accelerating, making your car faster off the line with no downside.

Running the motors all the time requires a constant source of electricity, and when you try to make that with a generator, you lose. You really want to use as much "free" energy as possible.
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