2013 Volt: 98MPGe, 38miles EV range

That was the point, since we know there is already parallel operation available.

It is the default mode for PHV. Simply exceed 100 km/h (62 mph) and watch what happens.

You have the choice of HV or EV-boost for high-speed travel.

 

That is patently not true. In Japan the highway speed limit is 100km/h so the PiP will stay in EV at all legal speeds and only use the engine when the motor and battery can't handle the demands on them. It's all about the demands of driving.

Batteries are expensive, low density and need to be carefully managed.
Price limits capacity,
Density limits utility and efficiency.
Stability limits capability..

To produce a reasonably-priced PHEV that doesn't significantly compromise utility or CS efficiency you have to have a small battery and the result is lower range and EV performance limitations.

That's the PiP. As I've written before that I think the PiP sets the parameters for Toyota's PHEV, with utility set, a price ceiling set and a range floor set, seeking to lower price and improve range only as battery price and density allow. Naturally, CS mode will improve as they try to improve the Prius line.

If you compromise utility and CS efficiency and allow a higher price you can have a larger battery and the result is a higher EV range and less restrictive EV performance limitations. That's the Volt.. I also think the Volt sets GM's parameters, but they're a bit different: GM has set a goal of 40 miles CD and 50 mpg CS and they'll be willing to hold the price and 4-seat design to achieve that goal, in part because the Volt's performance makes it an easier sell as a $40,000 car.

 

I would say the prius battery capacity was chosen before prices on batteries started coming down, and the range and top speed seem chosen for the Japanese market. These were not bad tradeoffs at the time, but I would expect the next generation to up the battery capacity more in line with american competion. In japan they don't need to worry as trade barriers will continue to keep ford and gm out. There is not a big hit on a bigger battery for driving efficiency, but it will take up more of the interior volume. This means a bigger battery needs to be designed into the car, not added on.

The prius phv does not turn on its ice to optimize efficiency, it does so to provide proper amounts of power with the lower cost battery.

The 2013 limped more than half way to the CD range, moving up from 35 to 38 aer. I would imagine the 50mpg goal is completely gone now, but they are looking to improve CS fuel efficiency in the gen II. Price seems to be the major challenge as gm tries to bring costs down to lower the price to the consumer. Battery prices seem to be coming down and weight for 40 mile aer should be lower when a gen II comes out. Volume needs to come up for much of the cost cutting, but higher cafe standards will help push this.

 

So, is EV-boost just another way of saying the car needs to use both power sources at higher speeds? When in EV mode and the car reaches that speed limit, does the system behave differently than at those speeds in HV mode? I take it, while in this boost mpg will go up, but the wall charge is being consumed. I thought that was one of the Volt's supposed flaws, using electricity at high speeds is less efficient. The Prius PHV avoids this inefficiency by using gasoline then when it is more efficient.

Is that not actually so? The Prius, in EV mode and above 100km/hr, isn't simply switching to regular hybrid operation. It is consuming both gasoline and wall electricity at that time. Is that it? EV-boost isn't really a selectable mode then. It's just EV mode at high speeds with ICE support, and the 150mpg should include a kwh consumption.

If gas economy could be markedly improved by more parallel operation, I think they would have done so. GM already abandoned the pure serial hybrid, and got slammed for that. Might as well taken it farther if it would have brought them closer to the 50mpg goal. The ability to select having the ICE at the single, optimized rpm for greatest efficiency might have been nice. I believe that was the original idea. It was for the Audi A1 PHV. It was dropped for multiple load ranges at varying speeds for noise, vibration, and psychological reasons. Easy to wish for it without knowing how annoying it actually is.

 

Combining gas & electricity at a more balanced ratio allows for greater efficiency, seeking opportunity otherwise lost by depending primarily on electricity or the engine.

70 mph in HV mode = 90% engine, 10% motor

70 mph in EV-BOOST mode = 50% engine, 50% motor

You get the choice of how to consume the electricity. It's not just one extreme or another. And when it comes to non-propulsion needs, like heat in the winter, that choice could provide quite an efficiency gain.

 

I too had not heard of this EV-Boost mode before you mentioned it here (at least not with that nomiker).

Now with this explanation it makes a little more sense. So you're saying a mode where I can tell the CD mode to discharge more slowly and prop that up with ICE operation to blend the two simultaneously over a long drive (wouldn't make sense when a recharge is within AER distance). That would be nice. I don't think it would work out to be that much different in overall efficiency, especially if you miss timed it and wound up getting to the charger with EV range capacity left, then you would have been better off using it instead of gas.

 

I think what your calling EV-Boost is simply blended mode. The prius phv uses it because the performance and/or efficiency would not be as good as staying in pure ev mode. BMW is working on tying in GPS so the car can look ahead at road speeds, hills, lights, etc to really optimize a mode like this for a trip. It would be cool if in the future toyota could look at driving conditions and optimize when it uses the battery.

On the porsche 918 and fisker karma they have sport mode that does the same thing, or you can lock them in EV mode. I don't think the traction motor is powerful enough in the volt to have this make sense. The motors and batters are very efficient in EV mode at all normal speeds so there is no reason for a blended mode.

Not really, you get to choose between blended phev and hybrid use in the prius phv. You can't choose at least in the american version to stay in EV. But especially with the battery size this is a good thing to leave up to the driver.

In the 2013 volt and 2012 ampera similarly, a driver can choose ev mode on the phev or hybrid mode via a hold button.

Both cars have hardware limitations to not add the other mode.

 

Your IEEE referenced above - NOT FOUND.

DBCassidy

 

Pulling the ICE and replacing with extra battery capacity sounds like the direction you are going in.

Best of luck,

DBCassidy

 

Volt was promoted as an extended range EV here in the US. You get 35 miles EV until the range extender (gas engine) kicks in.

With the inclusion of the Hold mode, Volt'll be using gas before the battery charge runs out. In another word, it'll be blending two fuels alternatively. The point of EREV falls apart and it starts to mimic Prius PHV operation with the exception of EV-Boost mode.

EV-Boost mode cut down the size of electric motors and battery size. Two engines working together for high power and high speed is a clever design. There won't be a "dumb" way of driving because the design won't allow it.

I am not familiar with the European Prius PHV EV top speed. I suspect the included EV-City button would allow the battery to drain harder for acceleration but they lowered the top speed to maintain the PHV battery life. That's just my guess. I don't think anything to do with the difference in air quality or density.

 

Two people that think differently tend to disagree. But the discussion can become constructive with different perspective as long as we keep it civil. The blog format does not enable that since new entries pushes the old entry down.

BTW, using the gas engine before the battery charge runs out was seen as a BAD thing, by the Volt enthusiastic. They used to bash Prius PHV about it. Now, they'll be spinning it as a good thing.

 

I don't think giving the driver the option to take it into hybrid mode before the battery runs out ruins the car at all. It is at the drivers discretion, it doesn't make the ability to stay in EV mode until the battery goes low go away at all. The volt doesn't default to hold mode or anything.

Its a car, it can of course be driven in a bad way. The owner can decide to not plug it in, or leave it in hybrid mode and not use the other power source. Having a less powerful and lower energy battery is a trade off, not a clearly superior design. Its what kit makers had to do to make conversions.

 

How is that a spin? It is a fact and it is the best way to put it into perspective. Gas engine and gas tank are heavy as well. Volt has both which is why weight reduction is so important. One way to cut weight is to assign more roles to each component.

I don't know about you but if two cars have equal green cred, I'll want the lighter one.

Recharge time is a counter to a spin. The spin is show-boating big MPG (electric miles included) without mentioning the amount of kWh used.

Slow refuel rate is the root of range anxiety. Volt has a gas engine but it uses premium gas at 37 MPG. Anxiety is still there when separated away from the plug, due to imbalance in hybrid system. The cleanest and most efficient 50 MPG ICE in an evenly balanced blended hybrid synergy drive eliminates that in Prius PHV.

 

It is also a deal breaker for me. I've been riding my Vectrix for 4 years now and I don't want to consume any more gas than I need to. Vectrix allowed me to go 100+km/h.
My trip to work is 12km (8 miles). I can recharge at work. That's more than enough for PiP's battery. However, 2 kilometers of my trip includes 100km/h road, which will force a would be PiP to warm up the ICE and consume the gas that I wouldn't need to and I didn't need to with the DEMO PiP, which went 100km/h with no problems.

I don't understand some Prius posters here, which tout the use of the ICE as a benefit. I really don't.

Look at my video driving a DEMO PiP. Starting at 2:00 minutes, I could do the 100km/h driving in pure EV. Driving a production PiP, that part of the road would be driving with ICE on. I simply don't want that.

 

They want the ICE for "just in case". The same mentality as SUV buyers wanting the off-road capability, just in case. The same trap, just cloaked with electricity.

 

This WTW analysis from US DOE done between EREV and Blended PHV shows the blended approach is better.

I like to see your IEEE link too, if you can provide a valid URL.

 

It's frustrating when they conveniently forget that previous stance. We've seen their refusal to address the past already. But realistically, there's no reason to dwell anyway. Witnessing the change is confirmation of being correct all along and a step forward has occurred. That's a measure of progress.

Accounting for the wide variation of real-world conditions takes time. The snap judgments we've been seeing lately are red flags, dead giveaways that generalizations are being made and/or some type of defensive response is at play.

Efficiency is a balance of resources available. With speed, length, time, temperature, traffic, etc. altering on a regular basis, it simply doesn't make sense claiming that the restriction of choice is best for every situation.