The New Hybrids

Joe S wrote:

> Don Stauffer in Minneapolis wrote:
>
>>Joe S wrote:
>>
>>>I don't understand what you're saying....are you saying that the
>
> hybrid
>
>>>model of whichever vehicle you are referring to (which is it, by
>
> the
>
>>>way?) consumes more gasoline than it's convential version?
>>>
>>>I know that the Escape hybrid gets much better mileage than it's
>>>conventional counterpart. So, again, some specifics?
>>>
>>>
>>>Joe
>>>
>>
>>I don't have the numbers on the Escape- maybe you could provide them.
>>
>>However, on the model I used as an example, it did get a little
>
> better
>
>>milage with the hybrid version, but not by a whole lot. If they made
>
>
>>the IC engine smaller and the electric larger, the improvement would
>
> be
>
>>a lot greater. Again, keep the TOTAL the same, so performance would
>
> be
>
>>the same (except for racing, when the average horsepower demand
>
> remains
>
>>high), with a better increase in milage.
>
>
>
> http://www.fueleconomy.gov/feg/findacar.htm
>
> 2005 Escape 2WD HEV - 36 City 31 Highway 33 Combined
> 2005 Escape 2WD (Conv 4-cyl IC Auto) - 22 City 25 Hwy
>
> So, that's 60% improvement around town, 30% improvement on the highway
> over its 4-cylinder brother.
>
> So, please tell us what models you looked at?
>
>
> Joe
>
The one I was complaining about was an intermediate sedan, and I think
the hyrid version was 31 hwy, 27 or 28 conventional. It was something
like an Infinity or Lexus.

Robert Briggs wrote:
>
> ISTM that the IC engine of a hybrid should be sufficiently powerful
> to be *able to do the job* without electrical assistance. If it is
> not then you could find yourself in something of a pickle.
>
But the whole idea of a hybrid is to use a smaller IC engine sized for
the average power requirement. Spark ignition engines in particular are
not efficient when throttled. Diesels are not as much affected by part
throttle, but still almost ANY internal combustion engine is not
efficient at partial power as it is at full power.

If you size the engine for peak requirement, then there is not much
advantage at all in making it a hybrid (except for the regenerative
braking).

Don Stauffer in Minneapolis wrote:

> Robert Briggs wrote:
>
>>
>> ISTM that the IC engine of a hybrid should be sufficiently powerful
>> to be *able to do the job* without electrical assistance. If it is
>> not then you could find yourself in something of a pickle.
>>
> But the whole idea of a hybrid is to use a smaller IC engine sized for
> the average power requirement.

No, that's really not the whole idea idea. The idea is to store energy
that would normally be wasted (regenerative braking), allow the I/C
engine to run at a more optimum speed when needed and shut off
completely when NOT needed, AND (if other design considerations allow)
make the I/C engine smaller and still more efficient.

If a designer feels the need to maintain a larger than "optimum" I/C
engine in order to have better peak performance, its STILL possible to
get much better efficiency out of the hybrid than out of a non-hybrid
with exactly the same I/C engine.

Steve wrote:
> Don Stauffer in Minneapolis wrote:
>
> > Robert Briggs wrote:
> >
> >>
> >> ISTM that the IC engine of a hybrid should be sufficiently
powerful
> >> to be *able to do the job* without electrical assistance. If it
is
> >> not then you could find yourself in something of a pickle.
> >>
> > But the whole idea of a hybrid is to use a smaller IC engine sized
for
> > the average power requirement.
>
> No, that's really not the whole idea idea. The idea is to store
energy
> that would normally be wasted (regenerative braking), allow the I/C
> engine to run at a more optimum speed when needed and shut off
> completely when NOT needed, AND (if other design considerations
allow)
> make the I/C engine smaller and still more efficient.
>
> If a designer feels the need to maintain a larger than "optimum" I/C
> engine in order to have better peak performance, its STILL possible
to
> get much better efficiency out of the hybrid than out of a non-hybrid

> with exactly the same I/C engine.


Exactly. The point isn't to neuter everyone's car so they get 50+ MPG.
It's to provide vehicles that have the needed capacity but that take
advantage of opportunities to make them a little to a lot more
efficient.

There are people who do need or want 250hp occasionally, but that
doesn't mean they have to tromp on the pedal all the time. As poorly as
he Cadillac 4/6/8 turned out, it still was an idea ahead its time.


Joe

In message >, Steve >
writes
>Don Stauffer in Minneapolis wrote:
>
>> Robert Briggs wrote:
>>
>>>
>>> ISTM that the IC engine of a hybrid should be sufficiently powerful
>>> to be *able to do the job* without electrical assistance. If it is
>>> not then you could find yourself in something of a pickle.
>>>
>> But the whole idea of a hybrid is to use a smaller IC engine sized
>>for the average power requirement.
>
>No, that's really not the whole idea idea. The idea is to store energy
>that would normally be wasted (regenerative braking), allow the I/C
>engine to run at a more optimum speed when needed and shut off
>completely when NOT needed, AND (if other design considerations allow)
>make the I/C engine smaller and still more efficient.
>
>If a designer feels the need to maintain a larger than "optimum" I/C
>engine in order to have better peak performance, its STILL possible to
>get much better efficiency out of the hybrid than out of a non-hybrid
>with exactly the same I/C engine.
>
The trade-off is reduced co2 emissions when compared to a pure IC engine
providing the same acceleration.
The downside is increased complexity and therefore increased up-front
capital cost.
Hybrids can provide big car feel (extra mass of battery etc.) with small
car economy.

I drive a turbo diesel with poor low speed acceleration but good
economy I would expect an equivalent hybrid to cost more, have similar
or better economy but have good low speed acceleration, note that the
design compromises necessary to provide good torque over the entire rev
range limits the IC power to weight/efficiency so the reduced rev range
of the hybrid can give good hill climbing at its optimum (reduced) rev
range.

I observe that except in special circumstances all consumer items ( and
species) get more complex as they evolve hybrids this is the way to go
for reduced emissions not hydrogen fuel which seems to simply move the
point of emission somewhere else.

--
dd

Don Stauffer in Minneapolis wrote:
> Robert Briggs wrote:
>
> > ISTM that the IC engine of a hybrid should be sufficiently powerful
> > to be *able to do the job* without electrical assistance. If it is
> > not then you could find yourself in something of a pickle.
>
> But the whole idea of a hybrid is to use a smaller IC engine sized for
> the average power requirement.

You seem to have missed my point in that paragraph.

By saying the IC engine should be "*able to do the job* without
electrical assistance" I mean simply that it should be sufficiently
powerful to propel the vehicle along the route.

Sluggish acceleration and plodding up a long hill are acceptable; sheer
inability to climb the hill without electrical assistance is not. (See
the last pargraph of my previous article.)

> If you size the engine for peak requirement, then there is not much
> advantage at all in making it a hybrid (except for the regenerative
> braking).

My present car has something like twice the power-to-weight ratio of my
previous one.

I reckon that cutting my present car's engine power by a factor of three
(or even four) would still leave me with something *usable* (except for
towing a caravan in a hilly area), but I would need third gear (rather
than fifth) for much of a trip on the M62 across the Pennines to Leeds,
and it would be uncomfortably slow.

Making up the balance of available power with the electric motor of a
hybrid would, of course, make such a trip much more pleasant, but it
shouldn't be required to make it *possible*.

On Tue, 22 Mar 2005 21:34:07 +0000, Robert Briggs
> wrote:

>Don Stauffer in Minneapolis wrote:
>> Robert Briggs wrote:
>>
>> > ISTM that the IC engine of a hybrid should be sufficiently powerful
>> > to be *able to do the job* without electrical assistance. If it is
>> > not then you could find yourself in something of a pickle.
>>
>> But the whole idea of a hybrid is to use a smaller IC engine sized for
>> the average power requirement.
>
>You seem to have missed my point in that paragraph.
>
>By saying the IC engine should be "*able to do the job* without
>electrical assistance" I mean simply that it should be sufficiently
>powerful to propel the vehicle along the route.
>
>Sluggish acceleration and plodding up a long hill are acceptable; sheer
>inability to climb the hill without electrical assistance is not. (See
>the last pargraph of my previous article.)

Robert, there are now several versions of hybrids on the market now:
those designed for pure good milage and those designed for people who
want there cake and want to eat it too.

Honda now markets three hybrids, the "Insight", a "Civic" hybrid and
an "Accord" hybrid. Of the three, the Insight is a pure high milage
type vehical, the Civic is a high milage version of the model but the
Accord is an extremely powerful car with a high horsepower V-6 as fast
as many pure high horsepower sports sedans. Naturally, it doesn't get
the milage the Insight does.

The Toyota Prius has a tiny engine for it's size and weight and a
constantly variable transmission to keep the engine at it's peak
performance point without shifting. The engine does have a 13 to 1
compression ratio, which surprised me when I heard about it, but it
uses regular octane gas.

The engine is a 1.5 L four, and the car's weight is almost 3,000 lbs.
Obviously, that size engine is going to run into problems maintaining
speed going up hills with AC running. The electrical motor is
designed to seemlessly cut in and assist when needed. There's nothing
wrong with this as the energy drained from the batteries is put back
in when the car heads downhill or levels out. You wouldn't notice
that the battery is helping, unless you looked at the data screen.

Corky Scott

Last nights news had a story about police now testing the Prius as a
cruiser.

Corky Scott wrote:
>
> Robert, there are now several versions of hybrids on the market now:
> those designed for pure good milage and those designed for people who
> want there cake and want to eat it too.
>
> Honda now markets three hybrids, the "Insight", a "Civic" hybrid and
> an "Accord" hybrid. Of the three, the Insight is a pure high milage
> type vehical, the Civic is a high milage version of the model but the
> Accord is an extremely powerful car with a high horsepower V-6 as fast
> as many pure high horsepower sports sedans. Naturally, it doesn't get
> the milage the Insight does.
>
> The Toyota Prius has a tiny engine for it's size and weight and a
> constantly variable transmission to keep the engine at it's peak
> performance point without shifting. The engine does have a 13 to 1
> compression ratio, which surprised me when I heard about it, but it
> uses regular octane gas.
>
> The engine is a 1.5 L four, and the car's weight is almost 3,000 lbs.
> Obviously, that size engine is going to run into problems maintaining
> speed going up hills with AC running. The electrical motor is
> designed to seemlessly cut in and assist when needed. There's nothing
> wrong with this as the energy drained from the batteries is put back
> in when the car heads downhill or levels out. You wouldn't notice
> that the battery is helping, unless you looked at the data screen.
>
> Corky Scott

Keep in mind also that one of the properties of electric motors is a
very high starting torque, and good torque throughout the low rpm range.
Thus, it will be hard to find a highway over the mountains that the
car will not climb, though lack of peak horsepower will mean it will
have to do so at a lower speed.

Also, keep in mind that with a good charge on battery, the battery and
electric motor are not limited by barometric pressure and altitude,
unlike the normally aspirated IC engine. The lower power if the IC
engine means that the battery will charge slower at those alititudes,
but once charged, the peak power of the electric is the same as at sea
level, except for some possible cooling concerns.