Volvo ReCharge: another serial hybrid

[Dr Mordrid]

Yup, and LONG overdue.

[Tjalfe]

Nice to see how cars are catching up with diesel electric trains

[Dr Mordrid]

They use programmable DC motor controllers that prevent you from burning all the rubber off your tires or cooking the motors if you 'hit the gas' or do trailing throttle moves.

This is necessary because these wheel motors can deliver 300-1,000 lb/ft of torque from 0 RPM and there is no tranny/transaxel but direct drive. The inboard motors like VOLT's front drive unit run 1,000 - 2,500 lb/ft each.

The GM fuel cell SUV in testing this fall has two 590 lb/ft wheel motors and a 1,700 lb/ft inboard

Silent is the word; these things are like riding in a glider save for what little tire noise there is. "Engine" noise can be provided by way of a USB thumb drive with several loops programmed in. Tesla started that and it looks like it'll stick in some form. Want your car to sound like a V-12? Go for it.

Fact is most system controls will eventually be by a vehicle intranet including instruments, steer-by-wire, brake-by-wire, throttle, lights and signals so having USB slots are to be expected if for nothing but music etc.

Also note that advanced traction control is implicit in the design, and there's talk of it being used with 4 wheel steering in the drive-by-wire.

MMM:

that platform is GM's Skateboard and it's in those 100 SUV FC testbeds they're passing around this fall, but it includes the suspension and steering. This was the sedan concept;

Bare chassis, covers off


Body swappable


Modular interior

[Nowhere]

OK, since this has become more general discussion about serial hybrids...

Do designs take into account that such car can be very silent and sounds are a big factor for pedestrians/cyclists in figuring out if there's a car nearby/how fast it goes?
And driving would be also weird/potentially more dangerous perhaps...I think sound of engine also plays a role in feeling how fast I drive/accelerate/how far I push the engine (though OTOH I imagine that these cars will allow for short "overchanging" of electric motors, which AFAIK doesn't cause damage...but how to determine in this case when it would be safe to "throttle back"?)

[MultimediaMan]

The Doctor is right...

It is far easier to design, build and maintain a constant RPM ICE with a specific load in mind than it is to build a conventional variable RPM ICE.

You can optimize the hell out of a constant RPM ICE to where it is more thermally efficient and compact than a conventional ICE.

For a conventional four passenger vehicle, the "sweet spot" is likely going to be a .75 liter to 1.25 liter 2-3 cylinder Diesel engine (turbocharged for altitude stability), or a two cylinder .6 Liter to 1 liter Gasoline Engine (also turbocharged for altitude stability).

For larger vehicles, like minivans and light trucks, you'd add about half a liter or so of displacement.

For the short term, inboard motors with CV joints are probably going to be a better option, because of cost and cooling required for a (current) technology electric motor.

I really like the idea of a Hybrid "platform" in which the basic hybrid powertrain is a very low profile semi-rolling chassis (everything sans suspension), with the body style of your choice put on the top of it. Quite a few of the "negatives" regarding parts commonality (batteries, mostly) and especially rescue personnel procedures could be standardized if everyone would use the same "hotspots" and "current zones" to avoid electrical and physical hazards when performing rescue/ vehicle recovery operations.

The idea of any new hybrid should be "sustainability" from manufacturing to end of life. This means more standardization of components and flexibility in manufacture rather than engineering an entire production line for one automobile.

[Dr Mordrid]

That and the way the engine is used differs in these cars; they're run at a constant RPM using lean-burn tech, keeping it at the RPM that is most efficient for the generator. They will also be small; 1-1.5 liter 3 cyl's, sometimes turbos, with multi-fuel capability.

[Gurm]

be interesting to know what milage it would get if you constantly used the gasoline engine to power the electric motors

"Mileage" is a pretty meaningless term with these new hybrids. The question becomes how many miles per KwH.

I'll try again, IF you would to drive this car without batteries and constantly use the gas engine to supply electricity, then then what millage?

Problem is that's not who they're marketing to. They're marketing to commuters and people who will keep it plugged in.

[Technoid]

>50 mpg in a 5-6 passenger prototype if you use up the charge then a full tank (740 miles), but for trips of ~100 miles with a full charge about 120 mpg (40-50 on charge, rest using engine charging). Note that the engine won't run all the time after the initial charge, just long enough to recharge.

thanks, but not exactly what I asked.

I'll try again, IF you would to drive this car without batteries and constantly use the gas engine to supply electricity, then then what millage?

[Dr Mordrid]

>50 mpg in a 5-6 passenger prototype if you use up the charge then a full tank (740 miles), but for trips of ~100 miles with a full charge about 120 mpg (40-50 on charge, rest using engine charging). Note that the engine won't run all the time after the initial charge, just long enough to recharge.

[Technoid]

be interesting to know what milage it would get if you constantly used the gasoline engine to power the electric motors

[cjolley]

Doesn't that look an awful lot like a railroad train suspension?

The "active suspension" part will negate the minuses, and then some.
Could possibly even dynamically cancel road noise.

[Dr Mordrid]

Ahhh but notice the absent large parts: swing arm(s), stabilizer bars, shocks/struts etc.

[Gurm]

Ahh yes, but those of us already used to alloys + low-profile tyres... will be in for a bit of a setback, handling-and-feel-wise, now won't we?

...

Then again, it'll be a nicer ride than your average Camry, so...

[Dr Mordrid]

No more jarring than if the vehicle has steel rims. The rim + motor, both mostly alloy, weighs about the same as conventional solid steel rims.

Another factor is that in many designs the wheel motor saves weight with the brakes; they're integral and very compact (read: much lighter) plus you get regenerative braking with reduced complexity.

Add low profile tires & it's a wash or better.

The lower C/G and advanced traction control per-wheel control provides are sauce for the goose.

Siemens eCorner design


(1) rim
(2) thin rotor/stator units
(3) electric wedge brake (brake-by-wire w/force feedback)
(4) active suspension
(5) electronic steering (steer-by-wire w/force feedback)

>
eCorner combines drivetrain, steering, shock absorbers and brakes

In the future, car wheels will take on a different appearance than today's familiar steel or mag wheels. With eCorner, a tire containing a sensor (Tire Guard) for monitoring the inflation pressure will be in contact with the road. Even the wheels' suspension of the future will significantly differ from today's design. While complex mechanical wheel suspension systems with oil-pressure spring elements ensure a comfortable ride for the passengers and permanent, reliable contact with the road, electronic circuits will play an increasingly significant role in the future. Within eCorner, electric motors will take over the task of ensuring contact between wheel and road. With this new suspension, hydraulic steering can be eliminated, giving automakers new degrees of freedom. In the future, each individual wheel can be moved to its own specific steering angle. When the speed is reduced, the wheel hub motors act as auxiliary brakes using a generator effect. The energy reclaimed in this manner can be used to charge the vehicle battery. Finally, in addition to the generator brakes, the electronic wedge brakes (EWB) can decelerate each wheel separately with maximum precision and enormous braking power to match the need of the driving situation.
>

[Gurm]

As Brian points out - there's a REASON why people pay extra for Alloy wheels. Here we've been trying to REDUCE wheel weight to improve ride quality for 20+ years, and now they're putting a MOTOR in each wheel?

I understand that engineering-wise it's a brilliant plan, but the ride will either be JARRING, or so cushioned by the suspension that you'll have NO road feedback.