OT: Hybrid cars

[Steve Litt]

On Sun, 15 Sep 2013 14:42:28 +0300
Mord Behar <mordbe0 at gmail.com> wrote:

> Hi
> I know that this is off-topic, but I really don't know who to ask.
> See, I need a large pool of Linux-like brains that live in Israel for
> this. I mean, people (like me) who track gas liters and kilometerage,
> wear and tear on the car, insurance and things like that.
> 
> Does anybody have numbers and experience to show how economical it is
> to buy a hybrid car, and which one?
> At what point of city-driving and non-city-driving does it pay to buy
> a hybrid car? Gas is really expensive now, and probably just going to
> go up. But hybrid cars are expensive too and the shelf life of the
> battery is 5-10 years...
> And I suppose that the terrain matters as well. In Jerusalem the
> hybrid car will use more gasoline than in Tel Aviv.
> Thanks.

Hi Mord,

I can't give any info responsive to your question, but let me add some
anecdotes. As an American, I've always driven big, six seat passenger
cars, many with V8 engines. Recently, after my 3.8 liter displacement
1993 Buick Park Avenue blew up on a road trip, I bought a brand new Jeep
Patriot with a 5 speed manual transmission and a 2.0 liter engine. I've
driven it 6000 miles, city and highway, including a road trip to and
from Chicago that consumed 3000 miles.

Here's what I found...

On the highway, my huge, old, 6 seater Buick got essentially the same
gas mileage as my new small, Jeep. 28 miles per gallon on the highway.
But in the city, with stop and go, my Jeep gets 23 miles to the gallon,
as opposed to the Jeep's 15 miles per gallon.

Now I'll hypothesize an explanation...

In the city, the Jeep's tiny engine uses less gas to accelerate its
lighter frame. But on the highway, the Jeep's 2.0 liter engine is
actually overwhelmed by hills, headwinds and the like. This engine is
so weak the only way to go 70mph (the highway speed limit in most of
America) is to run the engine at about 3500 RPM. The Buick, on the
other hand, had a lot more torque, so it had a transmission that could
run the car 70mph at maybe 2800 RPM, which is a much more fuel
efficient RPM than 3800.

From what I understand, the big mileage gains for hybrids come in city
driving, so maybe simply getting a tiny engine would accomplish the
same thing. If, once in a while, I need serious acceleration from the
underpowered Jeep, I just run it up to 5500 RPM, which is probably
30mph in first, 50 in second, and almost 70 in third. In those
situations, my Jeep accelerates as fast as most cars on the road,
except Dodge Hemis and the like.

I think for highway driving on relatively flat land, the only way to
gain mileage is to make the car more streamlined. On hilly highways,
perhaps hybrids' regenerative braking can gain some mileage over
regular cars, but then again, on all but the biggest hills, I can just
push in the clutch and coast down the hill, reducing my gas useage to
idle, which is very low on a 2.0 liter engine.

By the way, my most gas guzzling car was a 1973 Ford Country Squire
station wagon with an old, malfunctioning 460 cubic inch (7.5 liters)
engine, that got 7 miles to the gallon. Luckily, gas was cheaper back
then. 

So, I didn't answer your question, but had a lot of fun not answering
it :)

Thanks,

SteveT

Steve Litt                *  http://www.troubleshooters.com/
Troubleshooting Training  *  Human Performance