mpg numbers are shown on website for 2016 Prius

You can compare Toyota Atkinson engine and Mazda Skyactiv directly in Mazda 3 hybrid, sadly it's sold only in Japan. I doubt that Mazda gets lover fuel consumption in that configuration (unfortunately JC08 is not good to compare that)

 

there is always some solution 'coming down the road'. but sometimes i think these articles are corporate speak, or politically motivated. maybe they hope to attract funding. who knows? it is what it is. right now, prius works, everyone else is a pretender.make a prototype and prove it, investors will flock to your better mousetrap.

 

No !
There is nothing official yet !

 

I happened to notice my wife really punched it into the Power zone on the Hybrid System Indicator, starting off from a light, on a level road. I mentioned something about trying to keep it to around 3/4 of the way up the graph, accelerate easier. I think we were still discussing the errors of my ways when we got home, lol. Gave up on that.

HSI is this thing, btw:

 

does the hsi bar react differently in different modes?

 

JCI has prototypes, and it appears that it will go into big auto around 2018. It takes 5 years for a car cycle, and they announced in 2014.

I have no idea where the 60% comes from though, its not from JCI.

EPA's test cycle does not reward start stop, although it appears to help about 10% in the city cycle in the real world, which would make something like the 2016 corola eco go from
30/42/35 to 33/42/37

Will car suppliers like JCI get the epa city cycle fixed to look more like real world driving, so real gas consumption goes down, and they can make more money selling their hybrid batteries?

If it adds $700 to the new car cost will those 2 mpg be worth it? Probably not unless we get $5 gas, but definitely in europe where the gas is already expensive.

Then the next question is prius versus micro hybrid corola or auris (for the hatch back) - 52 mpg versus 37 mpg over 200,000 miles the gen IV prius would save 1700 gallons of gasoline, at $4/gallon that is $6800. A corolla eco LE with start stop would be about $20,000 with the start stop system. My guess is at $2 or $3/gallon gas that eco with start stop would get a lot more sales than a hybrid.

 

I didn't see anything claiming or substantiating anything like 60% motor efficiency. Did I miss something?

What I did see in the attached link was a claim of up to 15% improvement in fuel economy. If we take typical current efficiency at 30%, a 15% improvement in fuel economy would be roughly equivalent to using a 35% efficient engine with the same transmission efficiency but without stop start.

 

Thermal efficiency is the measure of how well an engine can turn fuel into work. Turning off the engine when it really isn't needed improves the vehicle's efficiency, but not the engine's thermal efficiency.

A ccgt plant can reach 60% thermal efficiency, but these are massive(100 tons or so) turbines that could also have additional turbines down the exhaust stream to eek out more work from the heat of the fuel.

The issue there was cost vs. the gains. The Malibu dropped the eAssist a year or so ago, because start/stop and an advanced engine got the same results. Look in the other direction, and eAssist let an old engine get the same vehicle efficiency as a new one.

If the price is low enough, a 48-volt system could save a lot of fuel by making it accessible for more models. Being developed by an outside company also means the costs and benefits can spread out over multiple car companies.

I think the Mazda hybrid is because they needed one for the Japanese market. The higher compression of the SkyActiv means it could be more efficient than Toyota's Atkinsonized engines, potentially.

Yes there is.

 

Mazda has worse aerodynamics, and from what I recall it was rated higher than Gen3 it is based off on JC08. The improvements came from tuning engine for low torque, and running engine at low manifold vacuum, something you can only do with HSD.

I remember reading somewhere an interview with Toyota exec presenting new engine improvement program and saying that Toyota needs to catch up to Honda and Mazda in engine efficiency.

If you compare Camry and Accord, the 20% improvement on Accord did not come from better aerodynamics or more efficient hybrid system only. Most of it from engine improvements.

 

Mazda 3 Hybrids gets 30.8 km/L under JC08 It has 0.26 drag coeficinet
Gen 3 Prius gets 32.6 km/L under JC08
Gen 4 Prius, I won't even check but if I recall correctly it was 40 km/l

Myth of super duper Skyactiv engine busted

We all know JC08 is not realistic, but we just won't get any better numbers for comparison.

edit: changed km/L

 

I have ran similar comparisons for Prius C vs Mitsu Mirage, and depending on price of gas and additional maintenance needs you are looking at 300 to 500k to recover price difference. So in real world cheap ICE car would have smaller TCO than hybrid.

I am not sure which car would be a better baseline for Prius comparison: Mazda 3? Honda Fit? Nisan Versa Note?

 

Hopefully that is 30.8 km/L not 30.8 L/km.

 

Not sure if this is reliable source:
13:1 Compression and 40 mpg on 87 Octane fuel? Introducing Mazda’s Skyactiv Technology

1lb = 453.6g, 1hp = 0.739kWh

0.28lbs/hp = 172g/kWh

I think 2ZR-FXE is rated at 230? 220 tops?

 

Right units are:

power
1hp = 0.739KW

SFC
0.28lb/hp.h = 172g/KWh

 

172g/kWh? That is 47% efficinecy. In your dreams, that is all I'm going to say.

 

I'd guess no, regardless gas pedal travel being different, if you've managed to get a certain throttle response, the HSI will display the same. Just found this, interesting:

HSI

 

The entire SkyActiv suite was developed without hybridization in mind.
"SKYACTIV-HYBRID combines a new SKYACTIV-G 2.0 engine developed exclusively for the hybrid powertrain and an electric motor to deliver both excellent fuel economy (30.8 km per liter under JC08 mode) and Mazda's trademark driving pleasure." - from the link above
And it sounds like, that while Mazda adapted the engine for the hybrid system beyond what Nissan did with the Altima hybrid, they still gave sport performance a priority.

Besides, Toyota thinks well enough of SkyActiv engines to use the tech in some of their up coming products. It's what they got for giving Mazda access to hybrid technology.

 

I think they were looking at 1.5L Mazda diesel for hybrid use, and supposedly hybrid SUV (CX-3? CX-5?) based.

 

The 60% thermal efficiency was what the Johnson Controls person being interviewed said on Autoline After Hours (podcast). They said 60% was possible, not that it had been figured out yet.

It could very well be a PR play to promote their battery technology and other automotive systems they supply.

I'm not for their products. I just thought their view of 60% ICE thermal efficiency was interesting. I have no desire to go backwards and buy a start/stop 48 volt ICE car, even if it did get 55 mpg. I'm very happy with my Prius.

 

here is another link to "theoretically possible" 80% thermal efficiency:
Opposing piston 80% thermally efficient NASA | Dreamer3000's Weblog

If you take into consideration that regular gasoline engine had theoretical efficiency of 40% with practical 25%, 50% is not impossible. Will probably require use of ceramics, HCCI, etc, and will achieve target efficiency in narrow range. Which is o'k if it is only used as a range extender.

GM toyed with idea of putting small turbine generator in early stages of Volt development but bulked at R&D costs and TTM time.