Re: Dark Side of Hybrid Vehicles

Gordon McGrew wrote:
> On Sat, 06 Aug 2005 04:21:09 GMT, "FanJet" <FanJet27@xxxxxxxxxxx>
> wrote:
>
>> Gordon McGrew wrote:
>>> On Wed, 03 Aug 2005 20:30:50 GMT, "FanJet" <FanJet27@xxxxxxxxxxx>
>>> wrote:
>>>
>>>> Gordon McGrew wrote:
>
>>> Really? Don't all cars have advanced engines and computer control
>>> these days? I am not aware of any particular advancements in the
>>> Prius' gasoline motor which would explain it's exceptional fuel
>>> economy. The computer only improves economy because it has a
>>> battery and motor to control. If manufacturers could get the same
>>> benefit without these expensive parts, why don't they do it? The
>>> fact is that the most advanced gas engine with computer control
>>> cannot match this efficiency level, at least not with acceptable
>>> performance.
>>
>> No, the fact is, with the exception of a truly minor assist from
>> regenerative braking, the hybrid's only source of energy is gasoline
>> - just like a non-hybrid.
>
> What did I say that would lead anyone to believe otherwise? The issue
> is how the hybrid system improves the efficiency of conversion of
> gasoline to kinetic energy. Saying that the only source of energy is
> gasoline is a red herring.

'Gasoline only energy source' needs repeating because inserting energy
conversions into an existing system doesn't magically result in an
efficiency improvement. In the case of the hybrid, the real improvement is
small and it is largely due to increased efficiencies that could be
economically added to non-hybrid vehicles - like low resistance tyres, for
example. Of course, like other efficiency improving hybrid systems, not
everyone likes the results. In this case, the handling ability of low
resistance tyres sux.

> Actually, the only source of energy is the Sun. Mother Nature just
> converted a portion of the solar energy to oil for our convenience.

Not exactly, but...

>> The comparison becomes even more interesting when you
>> consider that the regenerative braking assist is rendered less
>> significant because the hybrid is required to carry the extra weight
>> associated with the extra electrics/electronics. Then, there's the
>> losses associated with mechanical > electrical > electrical >
>> mechanical and all the way back for regenerative braking (maybe less
>> the dc > ac conversion). Just doesn't add up.
>
> Of course, any conversion from one kind of energy to another involves
> inefficiencies. Merely listing them out says nothing about the
> overall efficiency of the system.

When they are non-existent in the original system, listing them becomes very
important.

> Honda did use regenerative braking of a sort on a Civic model about 15
> years ago. The computer would only allow the alternator to supply
> power when the vehicle was decelerating (or if the battery charge
> dropped too low.) It's benefit was pretty small.

So simple. They should've kept it.

> Diesel locomotives drive generators which power electric motors which
> move the train. Why not just have the diesel engine turn the wheels
> directly? Because the use of electric conversion is more efficient
> overall, even though the extra conversion involves a loss of energy.
> The railroad companies don't buy diesel-electric locomotives so they
> can brag about driving a hybrid. And all the energy comes form diesel
> oil.

Actually, diesel-electric locomotives are the way they are for reasons
completely unrelated to efficiency. Understandable when you consider that
the design dates from a time when fuel efficiency wasn't a design
consideration. Reliability was the paramount consideration.

>> And, there 's more to the story too. The performance boost you're
>> referring to is only there for a brief period of time. Soon the
>> batteries need a charge and the ICE isn't powerful enough to fully
>> charge the batteries and simultaneously power the car so, it mostly
>> powers the car. There is no free lunch.
>
> You seem to believe that everyone who buys a hybrid thinks he owns a
> perpetual motion machine. The fact is that the performance boost is
> only needed for a short time. Most car engines spend only 1% of their
> working hours producing their rated horsepower. There is lots of
> extra capacity for charging the batteries.

This depends entirely on need. Some needs are serious and immediate. For
example, if I've just exhausted the battery by getting to speed and jocking
for position on an interstate, what happens if I need maneuvering power to
avoid a potential accident situation? In this case, today's hybrid is
actually a safety liability. I'd be interested in know the source for your
use of 1%. You need to keep in mind that the 'lots of extra capacity for
charging the batteries' consumes gasoline that would not be consumed in a
non-hybrid vehicle.

> Other posters have listed numerous reasons why hybrid systems increase
> efficiency. It could be all academic except that hybrid cars are at
> the top of the chart for high-milage gasoline road cars.

Other than quoting MPG figures, not really. The only system that is a net +
is regenerative braking and, truth be told, it's not that big a deal. The
chart topping had much more to do with driving style & political posturing
than science.

>
>>>> So, when you think
>>>> current hybrid, you should think Fahrfurnugen, Cab-Forward design
>>>> or hemi. You might also throw in extra profits & CAFE.
>>>
>>> I thought everyone was saying that the manufacturers are losing
>>> money on hybrids. As for CAFE, it wouldn't help your CAFE if it
>>> didn't improve milage.
>>
>> Not sure what everyone else is saying but I can tell you for sure
>> that the car makers aren't philanthropic organizations. Nearly all
>> of them improved CAFE figures by simply insisting that everyone use
>> 5W20 weight motor oil. The manufacturers didn't charge a thing and,
>> other than adjusting documentation, it didn't cost them a anything
>> either.
>
> And it didn't provide much benefit either. Can you point to any cars
> which increased their EPA milage ratings by even 1 mpg as a result of
> switching to lighter oil?

True but the change apparently netted the manufacturers what they needed and
that's what they were after.



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