What design change would you make for 100 MPG

[John in LB]

OK, here is an opportunity to consolidate in one place the great ingenuity of Prius owners. If Toyota or any other major manufacturer was considering building a car with the objective that it had to get 100 MPG on the EPA combined test, what changes would you make to the Prius design to achieve that goal?

Here are some ground rules:

- It has to be a commercial success - Nothing so weird that the public won't buy it. But for the moment, it does not have to be economically limited (let's say it can sell for as much as $100,000 - but not more than that (e.g., it can't be made out of solid titanium)
- It has to have 4 wheels on the ground.
- It has to accommodate 4 passengers with a maximum weight carrying capacity of 600 lbs.
- It has to be certifiable for the USA market from a safety standpoint
- It has to have air conditioning and several comfort features (can't be a box on wheels).
- It can use any propulsion system (including Diesel, gasoline engines, electric, etc..) - but it has to be able to go 300 miles without a fill up or a recharge.

Be specific, we all realize we can make the car smaller and lighter. The trick is how would you do it.

Also, your suggestion, in itself, does not have achieve the entire gas mileage improvement. Any piece which contributes towards the goal is helpful.

[bwilson4web]

<div class='quotetop'>QUOTE(John in LB @ Mar 24 2007, 01:01 PM) [snapback]411516[/snapback]</div>

OK, here is an opportunity to consolidate in one place the great ingenuity of Prius owners. If Toyota or any other major manufacturer was considering building a car with the objective that it had to get 100 MPG on the EPA combined test, what changes would you make to the Prius design to achieve that goal?

Here are some ground rules:

- It has to be a commercial success - Nothing so weird that the public won't buy it. But for the moment, it does not have to be economically limited (let's say it can sell for as much as $100,000 - but not more than that (e.g., it can't be made out of solid titanium)
- It has to have 4 wheels on the ground.
- It has to accommodate 4 passengers with a maximum weight carrying capacity of 600 lbs.
- It has to be certifiable for the USA market from a safety standpoint
- It has to have air conditioning and several comfort features (can't be a box on wheels).
- It can use any propulsion system (including Diesel, gasoline engines, electric, etc..) - but it has to be able to go 300 miles without a fill up or a recharge.

Be specific, we all realize we can make the car smaller and lighter. The trick is how would you do it.

Also, your suggestion, in itself, does not have achieve the entire gas mileage improvement. Any piece which contributes towards the goal is helpful.
[/b]

You can already achieve 100 MPG at speeds between 15-25 mph. What is the target speed(s)?

As for technical changes, here is my short list of Prius mods:

• exhaust energy capture - ammonia absorbsion AC, exhaust to cabin heat-pipe, turbo alternator
• pressurized wheel bearing lubrication
• dry-sump transaxle - all gears and cooling are pump lubricated and cooled
• all pumps including ICE coolant, electrically, demand operated
• fully enclosed and baffled ICE and underbody
• low-drag radiator coolant loop built into hood
• descending front air-dam and side skirts at speeds above 50 mph
• replace all rear view mirrors with cameras
• incorporate antennas in front and rear window glass
• thermoplastic-fiberglass bodies
• driver and passenger, fully articulating, electric seats
• 70+ psi tires on carbon fiber, enclosed wheels, with active, inertial suspension
• smart cruise control
• recessed windshield wipers
• Rain-X dispensor

Bob Wilson

[John in LB]

Bob, I was definitely hoping you would answer.

You definitely do not get off that easily however - especially an expert like yourself.

First off, the car has to be a commercial success - so let's say it has to have a top speed of 90 MPH and be able to accelerate at what the public would consider reasonable (can be slightly less than the Prius, but not substantially.)

Now... for the hard work, next to each of your suggestions, give us an idea of what MPG improvement (EPA test basis) a Prius with the suggested improvement would get - take a swag, does not have to be precise.

Finally, at the bottom of your list, tell us what you think the overall NEW vehicle would get for MPG (does it actually achieve over 100 MPG? or just almost gets us there?)

Thank you very much... Looking forward to your reply.

[Tideland Prius]

<div class='quotetop'>QUOTE(John in LB @ Mar 24 2007, 11:01 AM) [snapback]411516[/snapback]</div>

OK, here is an opportunity to consolidate in one place the great ingenuity of Prius owners. If Toyota or any other major manufacturer was considering building a car with the objective that it had to get 100 MPG on the EPA combined test, what changes would you make to the Prius design to achieve that goal?

Here are some ground rules:

- It has to be a commercial success - Nothing so weird that the public won't buy it. But for the moment, it does not have to be economically limited (let's say it can sell for as much as $100,000 - but not more than that (e.g., it can't be made out of solid titanium)
- It has to have 4 wheels on the ground.
- It has to accommodate 4 passengers with a maximum weight carrying capacity of 600 lbs.
- It has to be certifiable for the USA market from a safety standpoint
- It has to have air conditioning and several comfort features (can't be a box on wheels).
- It can use any propulsion system (including Diesel, gasoline engines, electric, etc..) - but it has to be able to go 300 miles without a fill up or a recharge.

Be specific, we all realize we can make the car smaller and lighter. The trick is how would you do it.

Also, your suggestion, in itself, does not have achieve the entire gas mileage improvement. Any piece which contributes towards the goal is helpful.
[/b]

Engine:
- Add Dual VVT-i (or that new stepless VVT-i system that Toyota's coming out with soon)
- Add direct injection

Body:
- Tuck the wipers and washer nozzles behind the hood
- Integrated rear window antenna (unless the current whip antenna was meant to create negative pressure)
- Carbon Fibre roof
Edit: - frameless windshield

Wheels:
- Even lighter alloys
- Replace compact spare tyre with mobile tyre repair kit

Lighting:
- LED DRLs
- LED taillights

Interior:
- Magnesium-framed front seats
- Radiant heating from exhaust pipe
- aluminium front seat rails



Hmm... I'm sure aluminium and titanium can be used extensively elsewhere but I'm unfamiliar as to the specifics of where they can be used. I know Toyota does use them because our 02 Camry XLE 4 cylinder loaded is 1,500kg yet the new 07 Camry LE 4 cylinder is 1,550kg. It managed to be heavier than our Camry XLE despite having less equipment.

[Allannde]

I am not a technician but have been following the news and trying to read between the lines.

I predict that Toyota will produce a car, perhaps the next generation Prius which will achieve 100 mpg and they will do do it by increasing the battery size, maybe to three times what it is now. There will be other refinements, but they will not be earthshaking. The car will have an EV switch and maybe five miles range in EV mode. The battery will have the same warranty which we get now.

It will achieve this by increased electrical assist. It will be as close to a Plug in Hybrid as can be done with the present battery technology and still meet the demands of the marketplace. It will meet all of the criteria which were set forth above.

[brick]

I don't think it would be worth 100mpg in typical driving, but I think that a lean burn engine a la 5MT Honda Insights and Civic Hybrids would make for some pretty substantial gains on the open road. The one caveat is that I would not want it if they could not find a way to eliminate the extra NOx emissions. Direct injection capable of a stratified charge might do the trick, or perhaps a clever exhaust treatment. If an Insight w/ lean burn can do 80mph at 55mph a Prius would probably be worth 65mpg, plus or minus due to the added weight and aero drag.

I think a more efficient battery or perhaps an ultracapacitor for electrical energy storage would be worth a solid mileage boost around town.

I hesitate to suggest the use of advanced composites to lighten the car, though that would work well. Problem is that you can't recycle carbon fiber, so I'm not a huge fan. Aluminum, also a la Insight, might be the right kind of compromise.

[iaowings]

What if you use a small diesel that turns a generator to produce electricity to run the car and the electric motors. A diesel can be very efficient under load at a constant rpm. You could even keep the batteries and allow the engine to shut off when not needed. I am not sure that would yield the 100mpg you ask for but it would probably get very close.

[bwilson4web]

<div class='quotetop'>QUOTE(John in LB @ Mar 24 2007, 01:47 PM) [snapback]411543[/snapback]</div>

. . .
First off, the car has to be a commercial success - so let's say it has to have a top speed of 90 MPH and be able to accelerate at what the public would consider reasonable (can be slightly less than the Prius, but not substantially.)
. . .
Finally, at the bottom of your list, tell us what you think the overall NEW vehicle would get for MPG (does it actually achieve over 100 MPG? or just almost gets us there?)

Thank you very much... Looking forward to your reply.
[/b]

I wasn't clear. The 100 MPG was going to be via what speed or driving profile? New EPA? Old EPA? One of the European or Japanese standards? City? Highway? Combined? Understanding the driving profile for the 100 MPG dictates the relative merits of each change.

The other, missing question, is the cost of each change. For me, this is the more interesting problem because it leads to "What can an individual do to retrofit one of these systems to their vehicle?"

Bob Wilson

[darelldd]

Heck, this is easy.

If I have $100k to work with, I'll give you 300 miles of range, astonishing acceleration, and at least 150mpg (of gas equivalent). Would have everything that the Prius has, as we'd just use that glider to start with (well, in reality, the Prius isn't a great glider for this, but we'll pretend for now) And the first prototype could be built in about a month.

I don't suppose what I'm going to say will surprise anybody: Remove the internal combustion engine. Stuff the thing full of Li-Ions (go buy a pack from Tesla to make this part easy) and put an AC Propusion drivetrain in there. Presto. Done. All goals met.

If produced in the quantities of the current Prius, they could sell (educated guess) for about $60k to begin with. And I'll be first in line.

This is not rocket science. This isn't anything that hasn't already been done. As soon as we talk about "improving gas mileage" we're hobbling ourselves to think in terms of having to burn liquid fuel.

OK.... so what did I win?

[John in LB]

<div class='quotetop'>QUOTE(darelldd @ Mar 25 2007, 08:44 PM) [snapback]412147[/snapback]</div>

Heck, this is easy.

OK.... so what did I win?
[/b]

The automotive X prize.... I think its $25 Million.

See http://auto.xprize.org/



<div class='quotetop'>QUOTE(bwilson4web @ Mar 25 2007, 08:04 PM) [snapback]412130[/snapback]</div>

I wasn't clear. The 100 MPG was going to be via what speed or driving profile? New EPA? Old EPA? One of the European or Japanese standards? City? Highway? Combined? Understanding the driving profile for the 100 MPG dictates the relative merits of each change.

The other, missing question, is the cost of each change. For me, this is the more interesting problem because it leads to "What can an individual do to retrofit one of these systems to their vehicle?"

Bob Wilson
[/b]

Bob, It is the Old EPA test that is the objective. So, that means the Prius gets 55 MPG combined and we need to improve that number to 100 MPG.

The challenge here is not to retrofit a Prius - rather we want to build a new generation vehicle with the Prius as our starting point to achieve the goals.

I realize a cost / benefit analysis will ultimately have to be done to prioritize which ideas should be implemented. However, for this phase of work, we are just looking for the brainstorm list - so, except for the vague limitations I indicated previously, lets' put costs aside for now.

Thanks.