Why hybrids are not AWD by default?

Honest John Back Room » Motoring discussion
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Thu 24 Aug 2023 12:51
Why hybrids are not AWD by default? - movilogo

Typically hybrids are FWD and they have motor besides engine in front.

But I wonder why not place the motors at rear and make it drive only rear wheels in EV mode?

Some cars do implement AWD but they put a 2nd motor at the back.

My question is, what prevents designers from shifting ICE transaxle to neutral and drive rear wheels only in EV mode?

I understand hybrid batteries are under the rear seats but as those batteries are not large as pure EVs, may be it is not too difficult to put a motor there too?

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Thu 24 Aug 2023 12:56
Why hybrids are not AWD by default? - Adampr

The Jeep Renegade 4xe has the set up you describe and it, apparently, works well.

I think it's probably technically harder to split the drive as you suggest than it is to feed two motors into one transmission.

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Thu 24 Aug 2023 13:15
Why hybrids are not AWD by default? - badbusdriver

Unless the car in question needs extra traction for either performance or off road use, there is not much to be gained from having a setup like that. If the hybrid is one version of an existing ICE range, the engineers have to use what space and funds are available. Because while there may well be plenty of space available in a bigger fwd hybrid, having the rear wheels powered by the electric motor would need a comprehensive re-design With a smaller car like a Yaris, having the ICE and electric motors under the bonnet powering the front wheels frees up more space in the cabin and boot, which is going to be more useful more of the time than having extra traction only ever needed in extremis.

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Thu 24 Aug 2023 15:26
Why hybrids are not AWD by default? - skidpan

But I wonder why not place the motors at rear and make it drive only rear wheels in EV mode?

That is exactly what the Toyota RAV4 does in the AWD models. But in a large SUV there will be plenty of space, in a family hatchback its different.

For the record I drove a RAV4 AWD model over a 20 mile test route. It did a pretty miserable 35 mpg according to the dash. Just to check I was not being harsh I drove the Superb 1.4 TSi 150PS we had at the time over exactly the same route immediately after, 51mpg on the dash. That RAV4 was not an economical model, the 2WD should be better.

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Thu 24 Aug 2023 17:44
Why hybrids are not AWD by default? - movilogo

I think it is due to power split device which combines rotation of fly wheel and motor. If engine and motor are driving direct axles it must be hard to sync them to same RPM

for 4WD (with rear motor) that is not an issue because speed is less.

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