How can they improve the fuel economy of the next generation Pruis?

The pip is already a 80 to 110 mpg car, you'll have to raise your sights.

 

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LOL. like a Dune "Freeman" suit?

 

Mechanically operated valves are going to be with us a long time, they keep improving with systems like Valvematic that you mentioned.

I don't have any data to back this up, but roller cams shouldn't be very inefficient. It's going to take fair amount of power to operate an engines valves as rapidly and precisely as they need to be operated, whether it's from a roller cam or electrical actuators. TANSTAAFL

Does anyone here know of a working real world engine with electrically actuated valves or even a good thorough analysis of the practicality of doing it? I don't have the Scientific American article that was mentioned earlier, but if it doesn't have some some real engineering analysis or test results to back it up, it's not very meaningful. It takes a good amount of power in a hot tightly packed space to operate engine valves.

 

my vote goes for

01) shutter air take grills(increase thermal efficiency): JimboPalmer,cwerdna
02) Rear view camera(safety): JimboPalmer
03) Variable ride height(safety): JImboPalmer
04) upgrade to a more powerful battery, e.g. Li-ion(increase MPG): JimboPalmer
05) better aerodynamics(increase MPG):cwerdna, jhinsc
06) weight reduction(e.g. alloy wheels, carbon fiber hood): cwerdna, wjtracy, jhinsc
07) silcon carbide FET transistor inverters: Kbeck
08) better LRR tires: jhinsc, Codyroo
09) ICE thermal efficiency improvements(ebh, insulate engine/cat): john1701a
10) rear wheel tire skirts, aerodynamic wheel covers: bwilson4web
11) eliminate the lead acid battery(lower weight): bwilson4web
12) softer shocks and harder LRR tires: bwilson4web
13) harvest heat from catalytic converter for cabin heat/window defroster: bwilso4web

I'd like to add
14) numeric RPM, GPH, SoC, and instantaneous MPG gauge on the Hsi display or heads up display. An audio visual *reward* indicator which goes on when the ICE and electric motors are both off - so the driver is aware the Prius is in a *perfect* glide mode.
15) eliminate rear spare tire (to lower weight)
16) exclusively use LEDs (lower power needs) . Light up cabin, especially control buttons, e.g. light up driver's door console button for window and door locks. LED lights for glove compartment and other storage areas. Use LED head lights, tail lights, turning signals.
17) replace pole radio antenna with a shark fin antenna (aerodynamic improvement)
18) eliminate driver center console put transmission contol back on dashboard ( weight reduction)
19) put a smooth flat surface on dash board to mount suction cup to put gps unit, CB/ham transciever, speed radar detector, Iphone/Ipad/android, or scangaugeII.
20) a more efficient air intake ventilation system that make use of air currents when the car is moving that can be used with the windows rolled up to be used instead of running the Air Conditioner.

21) a portable emergency generator mode - use the Prius to run a 24 cubic foot refrigerator and/or a 2 ton heatpump. in an emergency. if you lost electricity to your home then a Prius can come to your rescue.
22) emergency jump start terminals - so a Prius can safely jump start another Prius.
23) inflatable temporary fish/boat tail for the Prius v - to improve highway MPG

24) tougher chip and scuff resistant exterior body paint. Or use photovoltaic exterior body paint to provide phantom charge for the Prius electronics (so a Prius could be stored for months at a time without the risk of the batteries going dead).
25) aerodynamic bike rack option.

 

The 3rd gen prius engine is as efficient as 220g/kWh. Small diesels top at 200g/kWh. Diesel will not work in Prius as the starting/stopping cycle would be too hard on diesel and the increased weight of bigger turbocharged diesel (to keep power constant) would probably negate the gains (at least in city).

I totally agree with the hydrogen. That was just to distract the public and to make sure no viable alternative energy competed with big oil.

 

Nice list to forward to Toyota R&D. I bet they will go via direct injection gasoline engine in future versions.

 

Our previous car, a second gen Civic hybrid, had variable lift valves. I believe hydraulics were used to shift the camshaft from low to high lift lobes. It happened under heavy loading. I'd always notice it on one fairly steep overpass, the car would start to lag, then pick up, I assume due to the shift to the higher lift lobes. I don't think the cost was too much, but not sure.

 

The SciAm article was written by a Honda VP, but the included list derives from a 2008 NHTSA evaluation. It lists "Camless valve operation (relative to variable valve)" as providing a 2.5% fuel economy gain, with a "Cost to Consumer" of $336-673. But part of my earlier post was based on a different article from an older engineering trade publication, not this SciAm article.

Other improvements listed included Direct injection, 1-2% gain, and Homogenous charge compression ignition, 10-12% gain. Also, Dual-clutch automatic produces a 4.5-7.5% gain over an automatic, better than a CVT's 3.5% gain.

The gains and costs noted are the NHTSA estimates. The author notes that the auto manufacturers have their own compilations, differing from the NHTSA estimates, but keep them as trade secrets.

 

^^^
On this note, the article I cited at Car and Driver: The Future of the Internal-Combustion Engine | PriusChat talks about some of the above technologies.

 

Well in Europe we have the Peugeot diesel hybrids, which whilst being a little over priced at the moment, are better than the Prius on economy and also beat it on performance. Having test driven one some months ago I found it to be a good drive but it did make more use of the HV battery than the Prius. Now if the battery is larger (can't find the specs) then that's fine, but if it isn't then I fear for the batteries longevity.

Prius t3 petrol hybrid; 72.4 mpg, 134 bhp, 460 litres of boot space, 0-62 mph/100kph = 10.4 sec
Peugeot 3008 SR diesel hybrid; 74.4 mpg, 200 bhp, 354 litres of boot space, 0-62 mph/100kph = 8.5 seconds

Mpg's are using UK gallons and based on the Euro test cycle. I guess the Peugeot will be similar to the Prius if tested under the US economy cycle.

3008 HYbrid4! (vehicle details)
http://www.peugeot.co.uk/media/peugeot-3008-hybrid4-prices-and-specifications-brochure.pdf

The only down side with the Peugoet diesel hybrid is the smaller luggage space but the car is much bigger inside than the Prius and has more storage room in the doors, under seats etc. Also the NOx emissions are high as these are not as regulated here but I'm sure they could cut this with a urea system at a future date = considering that many Peugeot diesels had that system way back in 2001 over here.

 

^^^
I think the emissions are a key problem. It seems like in order to get a diesel to become clean enough to be legally sold in all 50 US states appears to involve a bunch of extra cost. That along w/the cost of hybridizing it might make it seem uncompetitive in terms of price. Also, diesel fuel usually costs more in many/most parts of the US for most of the year (http://www.fuelgaugereport.com/ has current prices).

So, besides the fact that Peugeot doesn't exist in the US anymore, whatever they (some other automaker) come up w/might not sell in sufficient quantities for justify development costs... Look at the sales numbers of "clean diesel" luxury brand cars at July 2012 Dashboard | Hybrid Cars.

 

I appreciate the extra costs and that it is unlikely a French company will ever sell cars in America. What I was showing was that a diesel hybrid does exist and does provide more benefits to the Prius. There were posts suggesting that the economy wouldn't be there or that performance would suffer. I was just showing that neither of these appear to be true and that a car that complies to the emissions and legal requirements of Europe exists. Sure it doesn't meet US emissions as it's not sold there but it could be made to comply if required; the same as all the other European diesels that are already sold in your market.

So a larger, faster, more fuel efficient diesel hybrid does exist. I believe a member on here bought the 3008 hybrid some months back and was very pleased with it. Having driven it, I too was pleased. It isn't as noisy as you'd think at all - you can bearly hear the engine switch on or off.

If any of you ever come to Europe on holiday I suggest you hire one and see

 

I stand corrected on this. It's really a remarkable piece of equipment (on the paper). 163 HP from 2L diesel engine sounds very impressive. The architecture of that hybrid is also very simplistic, diesel engine powered front and electric engine powered rear wheels giving a functional AWD solution. This how I always thought hybrids should be made.
But, I can see how they charge a premium price for that car.

 

I suspect that the reason Toyota engineers choose a lead-acid battery for the accessory battery is low self-discharge rate. People already have problems at the edge on this issue. Do we have a lighter weight battery chemistry with a lower self-discharge rate?

 

The fuel savings from a cam-less engine come mainly from better valve control, not reduced friction. The big one, throttling and pumping losses the prius already reduces greatly. As I mentioned toyota does already have a variable lift system, its just expensive, and can not do some of the trick things the camless design offers. Fiat and mazda have figured out how to make variable lift systems inexpensively, and I expect toyota will get there on their own, or license some mazda patents.


For example Ricardo has some engines swapping between 4 cycle and 2 cycle mode and can do cylinder idling on the fly. That Allows a 4 cyclinder camless di engine to act all the way from a 2 cylinder atkinson to a 4 cylinder 2 cycle. This is future tech, but camless valves may be the least expensive way to implement a hybrid hcci/miller cycle engine.

Everyone has them running in the lab. Cargine has run a saab with electrically controlled pneumatic valves for a couple of years
Free Valve Technology | Cargine
THe design may make it into a super car soon.
Koenigsegg to Deliver First U.S. Agera in June, Working on Camless Engine

 

You do want a separate battery to buffer the 12V for accessories and to start the car. Nimh discharges too fast. That leaves lead-acid or lithium. The lead-acid is used because it is cheaper. Porsche does have a lithium option, and toyota might be able to get lithium battery volume up to design one that is not much more expensive than the lead acid, but it will add some cost to lose the weight.

 

The problem with a diesel hybrid is that the costs are higher than the benefits. Diesel hybrid should get greater fuel economy. In Europe the costs are less though. The US requires more expensive emissions control equipment, and does not have the tax advantage there is in europe. The question really is are people going to pay more and have more tailpipe emissions for the small gain in mileage.

I just don't think its a good segment. Europe doesn't seem to like hybrids much, I'm curious to see if the peugot sells.

 

We're getting there though it depends on the Country. Peugeot offer 4 hybrid options but at a higher cost, Citroen offer a few too. We have the various Toyota and Lexus offerings, Hondas and the Volt/Ampera. Ford don't have any hybrids despite offering them in the US.

The trouble we seem to be having is that manufacturers believe they can charge a premium for them but forgetting that diesel manuals (60% of cars are manual transmission here) can almost get the same economy of a hybrid for 30% saving on purchase price. Also, take Toyota with the PIP; the UK base Prius costs the same as the US versions once import and sales tax are added, but the PIPversion is about £5,000/$8,000 more expensive. Why? I guess profiteering or greed, but sales of these is just not happening. Would you pay £32,000/$50,000 for a Prius plug in? No, neither would I!

I think Europe is so varied but manufacturers want their cars to sell in ALL countries. Hybrids and EV's would sell here in the UK; Toyota could import some of their JDM cars or even the RHD Aussie Camry hybrid and sell them, but they have to offer the full selection right across Europe. Unfortunately what might sell in Hungary might not here and vice versa.

 

Lithium Battery Technology for Non-Hybrid Cars - RoadandTrack.com