Centurion 128-mpg ... and smaller engines

[dcb]

Originally Posted by Ken Fry

...(in my case each is 90% efficient)...

How does efficiency change with load and rpm for the generator?

How does efficiency change with load and rpm for the motor?

How about the controller?

What is the overall efficiency in terms of vehicle speed and load?

And is energy moving "through" the batteries? What conditions affect the charging/discharging efficiency? (not counting regen)


Like we don't consider ICE engines to be really 35% efficient because of operating conditions, we should not make the same mistake with electrical drivetrains, no?

[drmiller100]

Originally Posted by Ken Fry

The hybridizing allows for near doubling of fuel efficiency, despite the generator and motor losses (in my case each is 90% efficient).





rid.

Just to be perfectly clear, have you actually purchased these 90 percent motors and generators yet?

Have you fitted them to a vehicle yet?

lets say we are cruising down the road, and the batteries get low.

So we fire up your 32 percent efficient IC. Lets say your cruise speed doesn't need all the generator can produce, so we try to recharge the batteries.

What efficiency do your batteries recharge at?

There will be a range where your 32 percent efficient IC will have excess power over cruising, and yet your batteries won't accept the excess amps the generator will accept.
In this case, the generator will not operate at peak efficiency, or the generator will start cycling on and off.

A lot.

By the way, where do we purchase one of these 32 percent efficient IC engines? Sounds pretty neat.

[pete c]

Not only 32%, but, 32% air cooled gas engine.

I was under the impression that liquid cooled gave a slight efficiency gain due to maintaining optimal head temps.

I guess in the end, there is one number that matters. How far did I get and how much gas/electricity did I have to pump into it.

[dcb]

That is three numbers

[JackMcCornack]

The OP asked in the OP (re the Centurion)...

Originally Posted by sgtlethargic

Do you think this had reasonable acceleration?

Not by today's standards of reasonable. My car is similar layout (but with the 21st Century version of that engine--lighter and a good 50% more powerful) and it's routinely mocked for its low acceleration. I doubt the Centurion could outdrag a loaded UPS van and I think passing slower traffic would take some serious planning ahead. That is, if one could find slower traffic.

Originally Posted by sgtlethargic

"Turbocharging the engine would increase maximum power and performance, and improve fuel economy as well.

I think that's true in practice, though not in theory (huh?). In my experience, what turbocharging gives me is access to more power when I need it, which is rarely, but it sucks plenty of fuel at turbo-power. Most of the time, it acts like its 25 hp NA version (I cruise at low power and zero boost) but when I want it I can get 33 hp, thanks to the turbo, but it's not a particularly efficient 33 hp. Point is, 33 hp is available on demand, though I probably only demand it an average of 20 seconds per hour of driving. To get the same power NA, I'd need the next size up, one cylinder and 400cc bigger, which would hurt efficiency at cruise and I'd still only want full power for 20 seconds an hour.

So in theory, turbocharging doesn't help efficiency, but in practice, it lets you run a smaller motor so the overall effect is positive. At least, that's my experience with the Kubotas.

Originally Posted by sgtlethargic

So, it looks like one needs a non-car/motorcycle engine to achieve 100 mpg with an ICE and no driving tricks.

Basjoos's Aerocivic site says he gets 100 mpg at a steady 60 mph and 120 mpg at 40 mph, with a standard Honda Civic lean burn engine and extreme aerodynamic mods, so it looks like it's possible. It doesn't look easy, though.

Originally Posted by sgtlethargic

What might be good sources for used gas and diesel engines of ~20 hp with an appropriate powerband?

The Kubota D1105T (like mine) is used in some commercial greenskeeper's lawnmowers, and some folks upgrade to the V1505T (the four cylinder version) and others just crash their mowers. Now and then I see these engines used on Craigslist for fifteen hundred bucks or so. Also there's a guy on eBay that's bringing in used Kubotas etc from Japan, only the NA models but if 25 horse will do you, they're there.

[sgtlethargic]

Originally Posted by JackMcCornack

...
I think that's true in practice, though not in theory (huh?). In my experience, what turbocharging gives me is access to more power when I need it, which is rarely, but it sucks plenty of fuel at turbo-power. Most of the time, it acts like its 25 hp NA version (I cruise at low power and zero boost) but when I want it I can get 33 hp, thanks to the turbo, but it's not a particularly efficient 33 hp. Point is, 33 hp is available on demand, though I probably only demand it an average of 20 seconds per hour of driving. To get the same power NA, I'd need the next size up, one cylinder and 400cc bigger, which would hurt efficiency at cruise and I'd still only want full power for 20 seconds an hour.

So in theory, turbocharging doesn't help efficiency, but in practice, it lets you run a smaller motor so the overall effect is positive. At least, that's my experience with the Kubotas.
...

My idea about turbocharging is very similar to what you said, so I guess I should've left [fuel] efficiency out of the sentence. Set up the engine more or less for cruise speed, and the turbo kicks in for acceleration needs- passing, climbing, etc.

[Ken Fry]

Hi Jack,
I'm a little taken back by your reaction, because I had you in mind when I wrote that the 128 mpg figure is misleading. Riley's headline claims that his car gets 50% better mileage than yours. I think that is unfair, because I doubt that there is that much difference. Nor do I think the Centurion is as efficient as the VLC.

For me, reporting a number that is not representative (or in the ball park) of performance on the combined EPA cycles is not OK for a commercial endeavor. The combined cycle is more strenuous than a 60 mph cruise for almost all cars.

You find Frank's comment to be just fine. It hits the nail on the head, you wrote. ("Another thing that really seems disingenuous today is the mileage claim at 35 mph... yes, it's ridiculous, but back then most fe claims were ridiculous.")

My comment, however, does not go so far as to say "ridiculous" or "disingenuous" (which carries a connotation of deception). I simply wrote that it is "misleading". But you seem to be characterizing my comment as coming from the "meanies."

But the fact is this: we are not living in 1982. Riley is advertising the car as 128 mpg, today. That is misleading because the standard today is the EPA figures, and per the fine print, this is not a number obtained in anything remotely close to the EPA cycles.

I don't agree with your contention (or Frank's) that the industry routinely dramatically exaggerated fuel mileage claims in 1982. There were many sources for fuel economy ratings (Road and Track, Car and Driver, Consumer Reports, Motor Trend, etc.) and not one of those reported fuel efficiency at a 35 mph cruise. I have followed this stuff quite closely for the last 5 decades, and can not remember any manufacturer advertising as a headline, a mileage figure produced at 35 mpg. The CAFE law had come out in 1978, and manufacturers were not getting away with dramatically overstating fuel efficiency. I've owned perhaps 30 cars in the last 45 years, and I don't recall any in which the mileage was dramatically overstated by the manufacturer.

It was not my intention to hijack the thread, incidentally. I used the case of a hybrid only to illustrate the effect of optimising: by picking components that are more or less OK, the cumulative effect produces rotten efficiency, By picking stuff that is excellent, the overall efficiency ends up fairly good. I was not intending the illustration to apply directly to the Zing: I don't have 95% efficient motors, for example, although they are available.

Then someone brought up the Volt, and had a misconception about it. So I responded to him, etc. If this site has an Off topic button, I would have clicked on it to minimize such posts. It seems rude to simply fail to respond. And it seems like a time waster to start a thread about random issues in plug-in hybrids, etc. -- there must be tons of that stuff here.

But I agree that the thread seems to have drifted away from the Centurion. I'll answer the other questions, from other posters (that seem to related to the Zing or Volt, in the Zing thread.)

The "awful" aerodynamics comment is the same one I would apply to the 1960's Jag XKE. I love the XKE's but their streamlining was all show no go. "Modern aero is not inherently better than old aero. The 1940's era MG streamliner had a Cd of what? .16 My point was just that The Riley is not stunningly efficient by virtue of aero. 65 mph on 17 hp is not impressive.

Regards,

Ken

[Ken Fry]

Originally Posted by dcb

That is three numbers

DCB, Doug, Pete:

I'll provide answers over at the Zing thread.

[Frank Lee]

I don't agree with your contention (or Frank's) that the industry routinely dramatically exaggerated fuel mileage claims in 1982.

You must remember that first set of EPA ratings back then... the little cars were rated at 40-50+ mpg and there was no way in hell anyone out in the real world was going to get that. Then the EPA revised their ratings and things got real. Basically I'm saying I think the last gen EPA ratings were about as accurate as we could hope for.

[user removed]

I remember in 1984 when I bought a CRX 1.5 new, I averaged 44 MPG for close to 50k miles. I was considering the 1.3, especially when I read about a car rag driving it at 55MPH until it ran out of gas. They got 73 MPG. I chose the 1.5 because it would do 0-60 in just under 10 seconds while the 1.3 took close to 14 seconds to get to 60 MPH.

If you want really slow 0-60 acceleration the 58 VW was really slow at something over 20 seconds to 60 and would really suffer trying to get to 70 MPH if it would make it at all.

Not many modern cars (if any) are slower than 0-60 in 10 seconds today. I also remember my 63 Valiant with the 170 fighting to stay at 40 MPG up an 8% grade on Afton mountain between Charlottesville and Waynesboro Va. 2-3-2-3-2-3 shifts for close to 7 miles climbing that grade, but I did manage 28 MPG on that trip. Supposedly 101 HP, but I had the carb set lean so probably not near that power. Used to like buying the Valiants when the PCV got plugged up and the owners thought the engine was gone at 40K miles.

regards
Mech