Next voltec, what do you think of the new rumors

We know Cadillac is planning to release a 2014my ELR at the end of 2013 with an improved voltec drive train. The rumor is this car will be using a new more efficient version of the 2.0L DI twin scroll turbo ecotec. That much more powerful engine would require a new motor/generator MGb to handle the different torque and rpm nature of the ice. This should get rid of the need for mountain mode and increase efficiency. Having adequate hp also will let gm lower the soc when the ice must come on, perhaps adding a couple more aer miles.

Looking at the 188hp c-max energi, 150hp for a Cadillac seems low. It seems likely that MGa is also changed, and a blended sport mode like the karma is added for more power.

With the changes needed for the cadillac, is it likely that the volt gets this big increase in hp and cost? I'm not sure. Maybe gm makes an atkinson version of the 2L, and has a different MGb. Or might it be less costly for R&D for the company to just decide the volt will stay expensive, but get more powerful. The c-max energy is a competitor but with its 2L atkinson it has both more hp in charge sustain and better efficiency.

 

Here is the original source of the rumor
Insider: 1.4L Engine Discontinued in 2014 Chevrolet Volt
Replacing the engine with a more efficient one will improve both highway and city mileage. Just replacing the engine with a more powerfull one along with the new battery chemistry, a bigger allowable SOC gets them to 40 aer. They could go back to 35 and put in a lighter less expensive pack with the redesgn.

The original design was a 3cylinder turbo. That may still be on the table. A turbo 2 liter for the cadilac elr, atkinson or multimode valve for the volt based on the new engine is also a strong possibility. The orignial design also included flex fuel, and I assume this would be more efficient using alcohol in a turbo.

Just looking at the prius, 98hp ice in a lower rolling resistance, lower cd car, makes me think that the current ice in the volt is too low power. A 3cyl turbo does add enough power though. A 2L is not much more expensive than a 1.4L. The original design still looks best to me, a smaller 3 cylinder turbo, but there is enough different about the volt that gm may not want to add its expensive and only has a 3 cylinder engine to the equation. A big question in my mind is the redesign a 2014 my along with the cadilac, or do they put the new drive train in the cadilac first and add it to the volt in 2014 in a 2015 my. If they go by what ford charges for their engines, a 2L turbo will add about $1200 to the sticker, a 1L turbo about $400, compared to the normally aspirated 4 on the current car. Since volume should wrangle more than this out of the rest of the car volt sticker should still go down with a more powerful engine.

 

It's rather simple why a more powerful traction motor make sense for a ELR with a blended sport mode. The extra hp can not be applied until higher speeds (35?) when the ice would be directly driving the wheels. Certainly the hybrid system could be reworked, but it is fairly inexpensive for the genset to provide more power in series, giving the driver the feel of single speed electric. There isn't a need with a volt, but if you are doing it for the Cadillac, it may not be expensive to use the same motor in both cars.

Simply adding a more powerful ice and genset allows you to get rid of mountain mode.

Let's remember that the genset seemed to be grabbed from the gm parts bin. Motor tech does move forward, and if you have time to redesign the ice, you definitely have time to get a better motor specified for the generator. A more powerful ice/generator combination also allows you to lower the SOC that the ice kicks in, increasing slightly electric range.

unlikely

Certainly the rumor can be untrue. I would expect a more powerfull more efficient ice, but the size could remain 1.4L

That seems no where in the direction the volt needs the new engine doesn't appear to be more efficient or more powerful. Certainly though, putting a turbo version of the 1.4L+genset, optimized for the volt may improve CS mpg and remove mountain mode. The 1.4L is missing DI right now though that the 2.0L has. We would have to see the bsfc curves to know for sure, but if they are talking the 2.0L I would assume it has a significant efficiency gain over the 1.4L turbo. The other bit of tech may be cylinder idling, which vw now does on one of its small turbos, and gm does on v6 and v8 engines. That may give a di turbo even more of an efficiency advantage.

I find it doubtful that HCCI is first tried in a volt. I would think that stale gas would make the system especially hard to build. HCCI shows greatest improvements in low power regions, while an EVER like the volt tries to increase performance by not running the ice in these regions. A turbo charged low rpm miller cycle is likely the highest efficiency boost for highway driving.

 

John, since this is my thread, I find your comment quite rude. The thread was clearly labeled as rumor. Some of us would like to know what is coming, if you do not, please instead of commenting ignore the thread. Your contribution only reflects badly on you.

The ELR has been confirmed for the end of next year, which means there are insiders knowledgeable on the new drive train.
From the previously linked article
Insider: 1.4L Engine Discontinued in 2014 Chevrolet Volt

These things in automotive publications, whether real leaks or fake ones never have a named source. The gm employee leaking this information, or toyota, ford, etc is not supposed to talk to the press. The story has been picked up by other publications which means it may have some legs.

 

+1

I've had a chance to flip through the slides. Thank you.

There is one thing that I did not think of, they say that lean burn is more efficient at heavier loads with forced induction (turbo charging). They seem to say a midsized car can stay in lean burn on the highway with a 1.4L di turbo. That along with downsizing may give it an advantage over a multimode DI 2L that mainly runs with atkinson valve timing.

The low hanging fruit on the slides after di, seems to be cooled egr, which toyota has put on the gen III prius.

They needed to add a urea based SCR system to reduce the NOx emissions. I wonder how lean they can run stratified charge without the urea. I'm sure urea would last a very long time in a volt, but assume they would not push the ice enough to need it.

 

Well let's look at what you said versus what I posted.
You said this came from vague and ambiguous comments. While the comments were specific. ELR at the end of 2013. New voltec in volt and ELR. The engine will change. They have tested the design with the 2L DI turbo, but the source is not sure whether it will make the car.

Nothing vague. Nothing ambigous.
Now you say a rumors thread is asssumptions without a solid scope. Well that is what rumors are all about. Don't read the thread if you don't want to think about the future. Waters wet too, you don't see me repeating it. Oops maybe I just did, but it would get tiresome if I started posting that on your threads.

Then Hope contributed to what ended up being hype.
I don't know if you think you think your f'ing yoda, but Wth man. I don't think a 2L turbo is necessarily good or bad. It certainly is different then what we were expecting. So no hype no false hope, but you being judgemental. Since you used past tense, you must know that something worse is going to happen. First a false accusation then a rude prediction.

Clear enough?

Now you may want to be the thought police on volt, and follow all the threads, but I do think its rather rude. There was no pretense or hype here. I thought when dr. innovation brought up the rumor on a different thread, it deserved one of its own. Do you at least get some understanding why now?

I hope that clears things up, and when you hop on a thread I start, you add something constructive instead of one of your trite nasty little sayings.

 

+1

I don't think they will add a urea tank either. They did have passive SCR on the slides where the car made the urea, but that required extra energy. I wonder how lean they can be on that 1.4 DI turbo and still get a SULEV rating on NOx. Would 35% cooled EGR as they mentioned keep it cool enough at 18:1? Stratified charge along with agressive cooled egr and down speeding turbo charging does get most of the benefits in a hybrid even at stoich.

 

First let's think about blended sport mode. Fisker gets its extra power by blending the battery power with the ice. This mode is likely to be included in the next voltec (voltec 1.5?) version. The horsepower in serial mode can only get as high as the traction motor can take, but this may increase. At higher speeds as the ice can blend in parallel more of its capability can be felt. I wouldn't expect it to be able to have the power of an atlantic, but we can expect more power, especially at higher speeds, in a 2014my or 2015my volt, simply from changing the software. I'm sure the new hardware will be designed for this too. This may not have made the original volt because of fear the epa would use it for mileage rating.

The other mode that did not make the volt was a eco-generator cycling mode. The engineers said that they could gain efficiency by running the ice in its most efficient band charging the batteries, then cycling it off and running back in ev mode until the soc reached a certain level. The problem seemed to be NVH and a disconnected feeling. I'm sure with a different ice they can move the efficient point lower in the rpm range, and giving people a choice can't hurt. This likely would not increase epa mileage, but would increase real world mileage. There has not been a rumor that this will make voltec 1.5, but gm engineers have been grumbling about not putting it in. Hyundai does a version of this when on cruse control.

Gm does have experience with how to make the 2L turbo more efficient, and should have good feedback about how current volt drivers use the ice, how the ice works as a range extender in the karma. Looking up the new 2L they claim that they have completely redesigned in from the one in the karma, improving nvh and reducing friction 16%. The bmw fisker chose in the atlantic, is tuned for efficiency not speed. I have no idea if gm will actually use the new 2L, but if they do they will likely increase compression, lower boost, and lower rpm for peak torque. Current compression slotted for the ats is 9.2:1, I would expect it to reach 10:1 of the bmw or higher. The current twin scroll turbo is 20psi, but the ice might be happier at 14psi.

Most of the benefits including both modes and even higher efficiency could come from a 1L di turbo as originally designed. It would also be smaller, lighter, and less expensive. It would have worse NVH as a trade off, and from a marketing point of view it would not be the best decision. That leaves the likely choices at 1.4L-2L 4cylinder engines that might have DI and may be turbocharged. I think the cadillac is likely to get that 2L turbo, and the karma will get an efficiency boost with a redesign. I don't have much of a clue what will make it into the new volt. Lutz is no longer there, if he was I think he would just shove the non-di turbo cruze engine in there, but I hope the new management makes a better decision.