mpg numbers are shown on website for 2016 Prius

Watch how she brakes, not how she drives.

 

You are right but I gave up, peace is more important than a few gallons of gas or set of brake pads.

BTW Prius C is much harder to maximize regen braking; if you want to recover as much as possible you need to brake much further out.

 

we agree on our better halves!

 

no way! We can't even agree who is the best English writer, Oscar or that screen play writer you keep quoting

 

I listened to Autoline After Hours interview a person from Johnson Controls (automotive supplier). They say there is a lot of room to improve ICE up to 60% thermal efficiency. Using start/stop technology and low voltage (<60 volts) and better thermal efficiency, they can meet mpg requirements well into the future without building an all electric or hybrid vehicle.

The cost to develop and mass produce a high efficiency ICE will not be too high. It will be years in the making though.

Johnson Controls Sees Opportunity in Low-Cost Hybrids | Industry content from WardsAuto

 

oh good, i can wait.

 

Start/stop does not require a hybrid, it just works best in one. (without a large battery, A/C while stopped is difficult, electric power steering may be problematical)
Almost all non hybrid cars are 12 volt, I am unsure where 60 volts is 'low'.

Start/Stop: Making the Most of Just Hanging Around

 

Another thing that is overlooked is making cars more aerodynamic. 1987 Renault Vesta II had Cd 3/4 of Gen4, so given the same powertrain you could expect 20-30% better MPG.

 

The 60 volt threshold limits the need for expensive safety systems to prevent electrocution. Here is an article about Johnson Controls battery technology.

Johnson Controls Sees Opportunity in Low-Cost Hybrids | Industry content from WardsAuto

 

doesn't that make it a 'hybrid vehicle'?

 

Mild hybrid systems with stop/go and low speed crawl are 48-60v and it is enough A/C, right?

 

Looks like GM's reviled BAS system. BAS Hybrid - Wikipedia, the free encyclopedia

 

My understanding is that the 48 volt battery starts the ICE, and runs systems (a/c, water pump, brakes, etc). It does not move the car. No electric motor like hybrids have.

The point of my first post on this tread is mostly that Johnson Controls believes the thermal efficiency of ICE will be up to 60% in the future. If this becomes a reality, we will see very large increases in mpg even without hybrid technology. There are many competing technologies to meet the MPG requirements in the coming decades.

 

Sorta kinda, but not full on like the prius.

1) screw the 10 year battery waranty. Put in much lower priced lithium batteries that you replace. CARBS rule slows innovation. That less expensive locally manufactured lithium battery is lighter and smaller than the big imported japanese nimh. If it lasts 7 years isn't that better than 10 tears and 3 times the price and twice the volume?

2) Drop the battery voltage in this mild hybrid to 48V that means you don't need as expensive safety systems. That should be plenty to run the AC and power steering, and starter for start stop.

The starter motor can assit on these micro hybrids, but not provide nearly the power.

Do you have a link to that 60%? I've heard 45% even from toyota, but the current gen IV engine is 40%, close to that level for gasoline. Diesel is a 50%, with some higher efficiency with duel fuels like diesel and gasoline or exotic engines. Maybe 60 mpg cafe, which is much more doable. The gen III prius gets 70 mpg on the cafe.

 

The biggest advantages in fuel economy can be done with engine OFF when the car is moving (glide), current simple S&S don't allow that (brakes and other accessories).

As for 60% thermal efficiency I call it Bullshit. we have huge heavy power plants with all sorts of systems and still 60% efficiency is considered very high. 50% will be a ceiling for the next 20 years at least.

 

<AHEM> The article date is "Oct 21, 2013" but I have other issues with Johnson Controls. Still, let me explain some basic engineering:

• 1 hp ~= 746 W
• 746 W / 60 V = 12.4 A
• 10 hp will keep an NHW11 at 45 mph on a level, no wind day
  • 124 A !

There is no 'free lunch' and Johnson claims about a 60 V system being a serious power source is just nonsense. Worse, the faster the car moves, the greater the reverse EMF (i.e., back voltage) that limits further current flow. These are basic engineering facts and data.

Bob Wilson

 

Read this, they have prototypes running at 57% efficiency. Of cause 57% in narrow range, so it is intended for series hybrid/BEV range extender applications. http://www.popularmechanics.com/cars/a8174/liquidpistons-hyper-efficient-engine-turning-the-rotary-inside-out-13817971/

With respect to JC I'd like to see them forgo 12v lead and get 48v LiON with stepdown to power 12v accessories at least 48v catches up. If you power a/c, steering, starter/alternator, water/oil/gas pumps and injectors with 48v, the rest doesn't need that much.

 

I read it, there is no claim that they have prototype running at 57%, that is just their target, or better say was, because this was 2012, surely you can show me a more recent article where they achieved that, or can you?

All this "cheap" or "mild" solutions need:
1. downsized, DI, turbo engine - because it will be running a lot in sub <8kW load, Prius use the battery under such conditions.
2. transmission, possible a double clutch with low losses
3. larger alternator/motor in one unit with inverter
4. all acsesories runnig on elecricity
5. bigger battery (Li-ion, NiMh) ~1/4 the size of Prius

This cheap solution suddenly doesn't look that cheap anymore and is quickly getting in the price range of Toyota HSD system, because HSD saves on DI turbo engine and complicated transmission, but it has more expensive hybrid system.

 

Took 15 years to get Atkinson to 40%, yet you believe Mazda will reach 50% soon.
Santa Claus governs...

 

I'll have to look at history, perhaps their website? Look around

But it was stated in interview with inventor. The beauty of rotary is packaging Mazda managed to package similar generator in spare tire sized pancake and cost when compared to TDI solution. At 56% thermal efficiency series hybrid will be more efficient than 40% parallel HSD, and with smaller battery more cost effective than full BEV.

HCCI and 1:18 compression ratio. BTW current SkyActiv is more efficient than Toyota solution in hybrid application, and it is Atkinson btw