S65's Thoughts: Mild Hybrids 

"S65" (granthp) 09/15/2016 at 07:45 • Filed to: Mild Hybrid, Hybrid, S65's Thoughts

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Welcome to S65's thoughts where I make a post about something that i thought might be a little interesting.

I’m not quite sure if america’s infrastructure is quite ready for full EV’s and even then I’m not even sure if battery technology is up to the task. Why not use a Mild Hybrid? Like a Ferrari LaFerrari or a Saturn Vue Greenline or a Honda Jazz with !!!error: Indecipherable SUB-paragraph formatting!!! I bet it would be cheaper than a plug in hybrid. I wonder if it would behave closer to a regular car? ( one that isn’t a Hybrid. )

Well, what say you good folks of Oppositelock?

random001 > S65 09/15/2016 at 08:24

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Aren’tt the Prius and the Volt mild hybrids? Or just hybrids? I guess I don’t know the difference....

jimz > S65 09/15/2016 at 08:41

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I think auto stop/start is more or less displacing mild hybrids. you get most of the benefit (not sitting there uselessly burning fuel) without the hundreds-thousands of dollars of additional cost.

SidewaysOnDirt still misses Bowie > S65 09/15/2016 at 08:45

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I want to be able to take advantage of all of the modern weight saving knowledge without fattening the car back up.

nermal > S65 09/15/2016 at 08:49

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I think of a mild hybrid as something like what GM did on the Malibu Eco or whatever, where they made the alternator go backwards to provide a small amount of electric boost when it wasn’t making electricity.

Tricks like this and cylinder deactivation, as well as air dams and grill shudders I’m all for. Auto stop-start does definitely save fuel in traffic, so good on that as well.

bhtooefr > random001 09/15/2016 at 08:51

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A mild hybrid is one that cannot be propelled solely by electric power.

“Micro-hybrid”: People trying to push stop-start systems and alternator cutoff as hybrids (this is not actually a hybrid at all, and nowadays, this is just called what it is)

Mild hybrid: Can assist the car, cannot propel the car without the engine running (GM eAssist, early Honda IMA)

Full hybrid: Can propel the car without the engine running, but all energy ultimately comes from fuel (most hybrids today)

Plug-in hybrid or PHEV: A full hybrid, except the battery is intended to be recharged from the grid (and is larger as a result)

Extended range electric vehicle or EREV: GM’s marketing term for a plug-in hybrid that has full power available in electric mode (Volt)

BEVx: California’s legal term for a PHEV/EREV that has shorter range on fuel than on the battery charge, and therefore qualifies for full BEV credits (BMW i3)

BloodlessWeevil > S65 09/15/2016 at 08:53

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It still adds thousands to the price of the vehicle and really does not increase fuel economy much (less than one mpg in my experience.) It is not worth it to the customer, but stricter CAFE requirements are forcing automakers to care about every tenth of an mpg no matter how costly.

That said, a few thousand dollars more can make it a usable hybrid with much more benefit to both the end user and cycle mileage.

random001 > bhtooefr 09/15/2016 at 08:58

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Thanks for that!

S65 > SidewaysOnDirt still misses Bowie 09/15/2016 at 09:16

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I feel like making lighter cars might solve this problem

SidewaysOnDirt still misses Bowie > S65 09/15/2016 at 09:18

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Worked great for the Mirage.

Snuze: Needs another Swede > S65 09/15/2016 at 09:32

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How about a “lite-plug-in-hybrid”, basically like an older Prius but the ability to plug-in to “top off” the battery pack. Because in a normal hybrid all the battery power ultimately comes from the ICE, which means its coming from the fuel, it just allows the car to store/”redistribute” energy in a more efficient manner.

I’m thinking imagine something like a Volt with less battery and a little more engine power. Cut the battery in half-ish, so you still get, say, 10-15 miles of electric range, which still covers a lot of peoples shorter trips. For me, that would cover my commute to work, so I could drive in on battery, drive home on gas. This would reduce the car’s weight, and free up a lot of internal space, and it would package easier, but you still get the benefits of a hybrid system. The smaller battery would charge more easily on 120V power, and in less time than the big battery, which means you don’t neeed a costly charging station anymore.

S65 > Snuze: Needs another Swede 09/15/2016 at 09:33

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You’re on to something

Snuze: Needs another Swede > S65 09/15/2016 at 09:43

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Honestly, of all the hybrids and such out there, the Volt is my favorite, at least conceptually. They really put some thought into how much the average person uses their car, most of the time, and sized everything accordingly. It’s not supposed to be fast, flashy, or anything like that, it really is the ultimate appliance car. It’s like it out Toyota’d Toyota.

But I think there’s room for improvement/changes. Instead of going all electric, I think doing something like I suggested in the Sonic would be cheap and affordable. The Volt starts at $33k, the Sonic starts at $16k. Using a smaller platform, less battery, reducing weight, I wonder if it would be feasible to then go to a smaller motor while maintaining a similar level of performance? That would reduce motor cost, and as I said we could cut battery cost in half. You might be able to get such a car in the low-mid $20's (I’m thinking $23-25k).

Even better, you could put the motor rear and make it AWD. That would help keep the underhood area uncluttered and shouldn’t raise the floor pan too much. You could now have electronic drive modes (as most do these days) with Electric, Eco, Sport, Bad Weather. Electric would run full electric till the battery depletes, perfect for running to the post office or 7-11. Eco would run like a Prius, electric at low speeds, gas at higher speed, with the battery charging/discharging and the electric kicking in as needed. Sport would run AWD and bias more towards using the battery/motor as a “booster” off the line and out of low speed corners, and as a boost at the top end to pass, etc. And Bad Weather would use torque limiting features to assist with traction in slippery situations, and shuttle power around to the wheels with the most grip.

bhtooefr > Snuze: Needs another Swede 09/15/2016 at 10:04

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You’ve basically described the Prius Plug-In - small battery, 11 miles EPA range on battery (and IIRC that 11 miles includes some gasoline contribution, due to the battery not supplying enough power for high-acceleration parts of the test cycle).

One problem with a small battery is that under high power demands, the battery can’t safely/reliably provide the required power, so the engine is required to start to help out... and then once it starts, it needs to go through its full warm-up cycle. Still, it does improve fuel efficiency.

There’s also the Ford Energi PHEVs, although their batteries are terribly packaged. IIRC 16-18 mi range on those, more power, and higher speed EV operation (so with gentle driving, they can stay in EV realistically on a commute, whereas the Prius Plug-In couldn’t)

However, it seems that most people who are interested in a PHEV want the EV experience (and zero fuel burned) in local driving, with an engine to support long distance driving. So, the Prius Prime has about twice the battery, has 22+ miles all electric range, and has more torque and similar power (I think slightly higher power, actually) in all electric mode than in hybrid mode (making it, in GM’s classification, an extended-range electric vehicle instead of a plug-in hybrid - this basically means that you don’t lose power because you went into EV mode). It’s still less than half the EV range and battery of the Volt, though.

Snuze: Needs another Swede > bhtooefr 09/15/2016 at 10:08

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Interesting, I had no idea that’s how the Prius Plug-In existed or what it’s features were.

Also, I find your last bit interesting, that people are shying away from PHEVs toward something like the Prius Prime or Volt that offers the “full EV experience.”

bhtooefr > Snuze: Needs another Swede 09/15/2016 at 10:12

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If you’re calling for putting a sole electric motor in the rear... you can do that, but you actually end up with a more complex gearbox up front as a result (your typical 6/7/8/9-speed automatic/DCT or whatever). The dedicated hybrid transmissions out there are amazingly simple, efficient, and flexible (GM’s implementation of the power split concept is more complex than Toyota/Ford’s (which is arguably simpler than even manual transmissions), but it’s still far less complex than, say, your average 4-speed automatic). Mind you, that “simplicity” is purely in the mechanical domain, the software to run a power split gearbox isn’t simple, but...

In any case, purely through-the-road hybrids are a thing, Peugeot/Citroen did some, but they weren’t really successful.

Now, you can combine a power split hybrid with a rear motor, and get some really effective results as far as torque vectoring goes, as Toyota’s been doing since the mid 2000s on the RX/Highlander hybrids, and now on the NX/RAV4 hybrids, and the JDM Prius e-Four.

AfromanGTO > S65 09/15/2016 at 10:16

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I always liked the Escalade Hybrid.

bhtooefr > BloodlessWeevil 09/15/2016 at 10:17

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Although, I know someone who had a LaCrosse with eAssist, and what it did was it torque filled the bottom end, making the 4-cylinder - pushing through a torque converter automatic, of course - much more drivable for those used to large displacement V6 torque. So, it may not have helped the 4-cylinder get much better mileage at all, but it made the 4-cylinder meet driver expectations, making its better mileage accessible.

Now, apparently it had really inconsistent braking feel (a problem that my Prius, a much more full hybrid, shares), and the packaging was awful (being a system retrofitted to an existing chassis). But, it did apparently help enable downsizing.

Snuze: Needs another Swede > bhtooefr 09/15/2016 at 10:24

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That’s a good point, and I probably should have been more clear that I would imagine having a power split hybrid system up front with just an electric motor in the rear. One of my professors in college did a lot of early research on split hybrid systems, so he really drilled it into our heads how it works, and your right, it’s quite simple from a mechanical standpoint.

I definitely don’t keep up with hybrid technology nearly as much as you do, so thank you for all the information. It’s definitely interesting to see all these different concepts out there.