Not only somewhat impractical.

Most people don't end up charging their battery because it still has an ICE so why bother? So now they have the worst of both worlds. Complex ICE machinery that needs regular service and heavy battery that doesn't end up being used.

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londons_explore 20 hours ago | parent [-]

Still gives decent efficiency improvements. You can always run the ICE at most efficient RPM. Never need to idle it, etc.

You can also have a much smaller engine for a much bigger car, since you only need to cover average not peak power usage.

You also in most designs eliminate the gearbox.

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mrob 20 hours ago | parent | next [-]

Only true for a plug-in hybrid with a series drivechain (a.k.a. "extended range electric vehicle"). The more common type has two parallel drivechains linked with clutches, so you still have all the drawbacks of a conventional internal combustion engine drivechain when you're using it.

	▲	tzs 18 hours ago \| parent \| next [-]
		> The more common type has two parallel drivechains linked with clutches, so you still have all the drawbacks of a conventional internal combustion engine drivechain when you're using it I don't know about the whole world, but in both the US and Europe nearly half of the hybrids on the road are from Toyota, so unless nearly everything else is two parallel drive chains linked with clutches whatever Toyota does is the more common type. Toyota uses a series-parallel system that works by having a planetary gear system that connects the ICE, a large electric motor, a small electric motor, and a drive shaft all together. The planetary gear system functions as a power splitting device and a continuously variable transmission. It lets them direct power flow in a bunch of different ways. Here's a summary based on Wikipedia. (MB == the bigger battery, 12V == the regular 12V batter, ICE == the ICE engine, MG1 == the smaller electric motor, MG2 == the larger electric motor): • Aux power: MB -> DC/DC converter -> 12V • Charge: ICE -> MG1 -> MB • EV drive: MB -> MG2 -> wheels • Moderate acceleration: ICE -> wheels, ICE -> MG1 -> MG2 -> wheels • Highway: ICE -> wheels, ICE -> MG1 -> MB • Heavy power, such as on steep hills: ICE -> wheels, ICE -> MG1 -> MB, ICE -> MG1 -> MG2 -> wheels • Max power: ICE -> wheels, ICE -> MG1 -> MG2 -> wheels, MB -> MG2 -> wheels • Regenerative braking: wheels -> MG2 -> MB • B-mode braking: Wheels -> MG2 -> MB, Wheels -> MG1 -> ICE This is a big part of why Toyota hybrids are at the top of reliability rankings. Compared to a pure ICE they replace the clutch, the transmission, the starter motor, the alternator, the reverse gear set, and the flywheel with the planetary gear power splitting device. the two electric motors, and electronics. The power splitting device has very few movings parts--just the gears themselves, a pawl that can mechanically lock the gears when parked, and fluid pumps. The gears only move by rotating, unlike in a conventional transmission where they also change position. This makes their hybrids mechanically much simpler than a pure ICE.
	▲	appointment 18 hours ago \| parent \| prev [-]
		This is something people say, but in practice the Toyota Prius is still a very reliable car.

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mschild 19 hours ago | parent | prev [-]

If you charge the battery, sure. Most people simply don't.

Data collected across 600.000 vehicles in Europe show that most people don't and that emissions are just a smidge under typical ICE vehicles. If you factor in the high emissions produced during battery productions it looks to be an overall bad package.

The idea itself is certainly good but the real world simply doesn't show it.

https://www.evshift.com/368695/do-people-actually-charge-the...

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fragmede 18 hours ago | parent [-]

You have to factor in regerative braking. Toyota's had ~25 years to get their system dialed in. Hybrid is worth it unless you're only ever doing freeway speeds flat out with no braking.

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londons_explore 17 hours ago | parent [-]

As a Toyota hybrid owner, you see that Toyota's design is kinda at a local optimum, hitting limits in every direction which sometimes rear their head in the user experience.

For example, the sluggish 0-60 is due to the design being unable to get all the power from the engine to the wheels at slow speeds, due to the electrical path through the CVT gearbox being too small.

The funny noises when going down really big hills are due to the system having no way to dump excess energy after the battery is fully charged and being forced to rev the engine at 5000 rpm with no fuel to waste some.

The slow throttle response is due to the engine always running at 80% throttle for efficiency, which means if you suddenly need more power you can only quickly get an additional 20% before waiting for the rpm to slowly rise and give lots of power in a few seconds.

EV's do have similar design limitations (drive on a racetrack and you'll need to let the hardware cool between laps), but they seem easier to overcome by simply sizing the system slightly bigger to hide the limits.

	▲	fragmede 16 hours ago \| parent [-]
		You make valid points, but to get almost 40 mpg in something that would get closer to 20 mpg without the hybrid system, there are gonna be some drawbacks.