Featured Chevy Malibu hybrid

That doesn't look kludgy at all.

It has a psd type mode that is very efficient and smooth adding power at low speeds, but adds a fixed gear mode with motor/generator that provides more efficiency and better connectedness on highways. I think the 3rd mode with just one electric motor is probably more efficient in those low power/regen braking situations. OK they have 5 modes instead of 3, but 3 make perfect sense and the malibu gets much better fuel economy than the camry hybrid, although the camry will accelerate faster with its more powerful engine.

The reason the malibu won't do as well as the camry or fusion hybrid is because the base car is not up to the standards of those other cars. It looks like a fine hybrid system to me, although the lower volume and 2 clutches will cost chevy more than toyota or ford.

Technically, I like the fact that they added clutches to overcome some of the shortcomings of hsd. Software could also be better in toyota and ford hybrids to be more connected, but this wouldn't also add the higher speed efficiency.

 

you're already writing it off?

 

Me or bob?

I don't think it will get major market share because its based on the malibu. Malibu has sold 58K ytd, while the camry has sold 96K. I can see it getting to the same take rate, but that is a lot fewer cars. I don't think someone wanting a camry or fussion hybrid is going to move to a malibu because it is more efficient.

Toyota is implementing a one way clutch in prius prime to make electric mode more efficient ;-)

Locking a fixed gear ratio reduces losses, you can see that in highway numbers malibu 46 mpg, camry 39 mpg. Sure the malibu has a smaller engine which may help a little, but my guess is this is mainly transmission/engine efficiency at US6 speeds. It will be interesting to get real world reports.

Definitely the clutches add cost and weight. Some of the weight is offset versus the camry by using lithium instead of nimh, but ford uses lithium too.

 

Based on my experience having driven a 2017 Volt in CS mode, this drivetrain's control laws aren't as smooth as the Toyota drivetrain, at least the P610. The Volt does have an additional one-way clutch, however, between the ICE and PG1.

 

I can remark on hardware. Given the hardware there should be a few shift points that don't feel as smooth, but should feel more attached. Low speed engine revs should match closely requested torq, as speed increases if power request is not above the fixed ratio, revs should get proportional to speed. This will be quite different from gen I volt, where engine was underpowered. Efficient range appears to be 12 KW to 40 KW. When more than 40 KW are requested that cvt type disconnect may happen, under 12 KW if there is battery power its going to be ice off. Malibu will feel more connected than the volt in charge sustain simply because the ice is more appropriately sized.

Now until reviewed, we don't know how good the software people have been, but the hardware should be better for efficiency and NVH than camry hybrid. I've driven gen I volt, and they definitely had some work to do on software. I haven't driven a gen II yet, but my guess is software is improved. Toyota though has been working on software since 1997, so if you like the feel, it is completely polished.

 

I think the Malibu was redesigned recently and has gotten better reviews than the version from 2-3 years ago that had less rear seat legroom among other things. In what ways is the new Malibu hybrid "not up to the standards of those other cars"?

Rather than using clutches and a separate high speed EVT mode, Toyota addresses the HSD efficiency aspects of higher speed operation by using DC-DC voltage transforming circuitry to boost the 200V battery pack up to 600V to make the motors more efficient. GM just drives the motors at pack voltage.

So, it's sort of a mechanical vs electronics solutions approach. Both methods cost money. GM's method probably scales better as power levels increase since Toyota presumably has to spend more on circuitry capable of handling more power.

The Malibu hybrid pack is capable of around 60 kW of power whereas the Ford Energi and Camry packs are around the mid-30kW, I think (I know Energi is 35 kW). The same transaxle is used between the Volt and Malibu except the Malibu has no one-way engine clutch (doesn't need it) and different hybrid-optimized motor rotors. The Volt battery puts out up to 120 kW.

How much more is the DC-DC circuitry cost for handling 30 kW vs 120 kW? I don't know. How much is the cost of adding clutches? I don't know. I don't think any of us is really in a position to make engineering judgements about the trade offs here. Engineering involves trading off multiple aspects not just judgements about abstract elegance.

So adding one clutch is okay but two clutches is terrible?

Just adding a clutch on MG1 is not all that useful by itself since the conditions where locking up MG1 is more efficient than eCVT is somewhat limited. GM mostly uses the fixed gear mode as a transition point in order to make synchronous low-stress clutch changes between the two ECVT/EVT modes. In some conditions they disengage both clutches to unlock the 2nd planetary gear (which normally does gear reduction between "MG2" and the wheels) in order to make the low-stress clutch changes by adjusting the "MG2" motor speed independent of vehicle speed.

Just putting a single clutch on MG1 in the Toyota HSD wouldn't buy that much flexibility.

 

Toyota’s Prius Prime Shows One Way for a Better Plug-in Hybrid

 

I have spent only a few minutes driving a 2016 Volt in hybrid mode (engine on) under limited conditions which wasn't enough to really make careful comparisons between it and the Prius control law behaviors. Also, my Prius experience is limited to 2001-2012 era models. I have not driven a 2016 Prius yet.

Can you go into more detail about how much experience you have had driving with the engine on in the 2017 Volt vs the 2016 Prius (or other Prius models) and what behavior and control behavior differences you noticed.

 

We still get 39 mpg highway in the camry hybrid versus 46 on the malibu. That electrical path is pretty efficient, but not as efficient as getting a mechanical path for more of the power. My guess is its not much more money for the clutches, but I don't know. The lower volume though probably makes the chevy system more expensive.
Compare Side-by-Side

The specs are 182 hp combined and 121 hp engine, that probably makes peak 61 hp or 46 kw. I'm not sure perhaps it puts out more where the engine is at lower power. Yep the malibu doesn't need that clutch.

 

let's wait for fuelly before jumping to conclusions.

 

It's not noted in the GreenCarCongress writeup, but the SAE paper says the Malibu hybrid pack can discharge a peak of 52 kW and charge at a peak of 65 kW during regenerative braking.

You can see this on page 2 of the limited free preview of the Malibu hybrid SAE paper at:

Development of Hybrid-Electric Propulsion System for 2016 Chevrolet Malibu

 

I'd say I had about 10 minutes in each vehicle, on mostly 35-55 mph roads. The Prius was driven on a test loop directed by the salesman, whereas the Chevy salesman slapped a dealer plate on the car, handed me the keys, and told me to go for a drive.

I couldn't do a thorough analysis of the different drivetrains' control laws, but I could feel the GM driveline shifting modes as conditions changed, although most of this was amelioriated by the main electric motor (what would be referred to as MG2 in a Toyota driveline) torque filling. I also noticed during one hard acceleration event that the ICE was extremely slow to gain RPM upon accelerator input (this car had 0 mi EV range when I was handed the keys, FWIW), although this did not translate to sluggish acceleration, due to the torque filling. Ultimately, though, I didn't get much of a sensation of directness in any mode - the EV torque came on pretty quickly (NOT instantly, though, unlike pure EVs like the Tesla Model S), but the ICE lagged behind. It's worth noting that a Malibu may have different control laws in this regard, though.

The Toyota driveline, however, was generally quick and smooth at responding to driver input. It didn't have a directness that I'd expect something like a manual transmission or a DCT to, but within a tiny fraction of a second at worst, it would smoothly get the ICE to the optimum RPM - even from EV.

Note that I'm a manual driver almost exclusively. I'd describe the Volt gearbox as "OK, better than most automatics, but not fantastic". The Gen 4 Prius, OTOH, seems to have the control laws and their responsiveness and smoothness nailed down to the point that it makes almost as much sense to me as a manual - push pedal this far, get this much power almost immediately (in Normal mode, anyway). Honestly, it felt a bit more direct than the Volt to me. (Although, I'd have to have more drive time in both, preferably on a road that doesn't result in upsetting the Volt's ride too much, to make that assertion more confidently - I was more annoyed by the Volt's atrocious (IMO) suspension tuning and awful ergonomics than the gearbox.)

 

Okay, good to know.

Did you feel torque shifts (as in a conventional automatic or manual) or did you just hear shifts in engine rpm?

The 2016+ Volt's engine-on hybrid mode's control laws are tuned to lead with the battery and electric motors in order to have the car's driving behavior feel more consistent between engine-off EV driving and engine-on hybrid driving. This is probably jarring for you because your ears are tuned to listening for engine rpm.

Not really. The 2016+ Volt is only 0.1 seconds slower from 0-30 mph than a Tesla Model S with a 60 kWh battery pack. It is officially 2.6 seconds 0-30 mph but Motor Trend clocked it at 2.3. This much faster and responsive than almost any non-Tesla plugin car and faster than most ICE cars. Sure, bigger battery Tesla cars are faster 0-30 mph but that's a rather extreme point of comparison. I'm pretty certain the 2016+ Volt is much quicker than a 2016 Prius or 2017 Prius Prime from 0-30 mph or at higher speeds.

Yes, it does. The Malibu is said to have engine rpm follow vehicle speed much closer and therefore more like a Prius.

Say more. I don't notice problems in these areas. Another person and I drove a 2016 Volt leisurely along country roads and at times very aggressively along winding hillside roads. It felt very good to me but then I'm not a suspension connoisseur. The new Volts suspension feel has gotten good reviews from car magazine and other media write ups. What ergonomics bothered you?

 

I felt torque shifts - the engine is rather quiet in the Volt, which helps make engine noises less jarring.

And, I should say, the time between throttle input happening and an increase of power delivered to the wheels seems to be higher than in a pure EV (at least the Model S), in the Volt. This wouldn't be measured in a 0-30 test, as those are usually done with gyroscopic equipment, and throttle lag won't be measured by that. I'm saying it's got a bit of throttle lag. Perceived throttle lag is less than the perceived lag on a large throttle input increase on the Prius, although I suspect that the Prius is faster to get some electric torque fill happening, it just has a lot less torque to fill with, which will increase the perception of lag.

As far as the suspension tuning, I found that the body was poorly controlled on uneven/rough roads, and I found that the Volt had severe body roll and pitch over road imperfections. The Prius was driven on a different loop, but some of the roads were in similar condition, and I actually noticed how composed the Prius was. As far as ergonomics, I found that interior controls didn't easily come to hand in the Volt, whereas they did in the Prius, and outward visibility was far worse in the Volt in every direction other than straight ahead.

 

There is an accessory power module on the Malibu hybrid battery. Does this replace the standard 12v lead acid?
Having ditched the 12v seems to be a minor talking point for Hyundai's Ioniq.

 

Maybe that is because you are already familiar with previous Prius or Toyota models with similar ergonomics?

I'm not saying you are wrong, but I didn't notice this and I have yet to read any reviews that state views like yours.