Dark Side of Hybrid Vehicles

What features is it missing?

 

Nor I but we certainly could think about it. I'm sure we could come up with
something.

Maybe it's because Honda hasn't jettisoned the excess weight and given it a
try.

Not I. CAFE is an average. Doesn't take too many government OK'd calims of
50+ MPG to do the trick.

Really depends on where and how you're driving, doesn't it? No doubt the HX
equals or bests the hybrid in some circumstances. In the end, it takes 745.7
Watts for each horsepower generated by a hybrid - completely ignoring
losses. Except for the small amount generated by regenerative braking, the
rest comes from gasoline.

 

The Honda has a very simple gage for charge/discharge. It's a 15
horsepower motor, which presumably is consuming 745*15 watts when it swings
to a full "assist" on the scale. It also then, presumably generates 15*745
when it swings full scale the other way. The time period when that is
happening is small in the overall scheme of things, but it is not
insignificant. Very light braking generates at least 1/3 of the scale for
extended periods.

The 2006 Honda Civic Hybrid IMA is rated at 15KW/20HP.

And the rest comes from gasoline.

 

Regen braking can, in theory, recover about 30-40% of the energy
used on the EPA city cycle. In reality, with losses it is probably
more like 10-15% increase in fuel economy.

A hybrid also allows the designer to readily shut the engine off on
idle. In theory, you could do this with any engine and just use the
12V+starter to get it going again. Practically, no one does this.
I suppose for drivability, NVH, and maybe starter motor wear issues.

A hybrid also allows you to run closer to the sweet spot of the
engine. For example, a gasoline ICE maxes out at about 35% thermal
efficiency. But in the normal driving load & rpm, it is more like
20%. By running at a higher load, where it is more efficient, than
required. And feeding this to the battery. Then subsequently
running at virtually no load, and letting the battery+motor run the
vehicle, the average ICE operating efficiency is increased.

Last, a hybrid allows downsizing the engine without sacrificing
performance. A smaller engine runs at an average higher load, where
(see above) it is more efficient.

So I'd say there are 4 solid reasons why a hybrid can return better
fuel economy.

Certainly there are minuses (cost, weight, complexity), and yes, the
real-world gains never seem to match the advertised EPA numbers.

 

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. 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. 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.

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.

 

How do they recharge it at night?

The Prius and the Honda hybrid have only one external energy source which is
gasoline.

 

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.

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

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.

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.

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.

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.

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.

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?

 

They have retrofitted a line voltage charging system, an option
available only if you have a hybrid system to start with.
Manufacturers are considering adding this as standard equipment to
their hybrid vehicles.

Would you please explain why this fact, which absolutely no one has
disputed, is relevant to this discussion?

Either cite a production car which is more efficient than an Insight
or concede that hybrid systems significantly improve fuel efficiency.

 

How does it compare to the Smart fortwo?

 

In Milan, Italy, all cars were required to auto-stop, with normal engines
and starters. This led to substantial problems with worn out starters,
premature battery failure, and led to dubious improvements in air quality.

The hybrid spins the engine at 1000 RPM to start the engine, higher than
the 150 RPM startup of a typical engine, yielding a cleaner startup. The
effort for the hybrid to start the engine is obviously trivial, and often
cannot be felt, whether auto-start or key initiated.

My Honda hybrid with CVT is far more pleasant to drive than a Civic with an
automatic. It is smoother and quicker in town.

My Honda highway mileage exceeds EPA estimates. My city driving is a
little lower. The Escape/Prius/Lexus hybrids don't perform up to EPA spec
in the city, because no one drives a city cycle. The fact that the highway
mileage is lower than the city mileage makes a "normal" blend of driving
lower than the EPA city rating, where consumers have gotten used to the
city EPA being something achievable as an average.


If you try to drive one of these undersized engines for something
resembling performance, the MPG plummets. It's a little tiny engine, and
it can't work hard for long. The regen isn't going to help out long term
without some gaps in the demand.

When I tow a horse trailer with my Escape, I get about 17mpg. That is
likely the same as a V-6, and I have less power for long grades, although
acceleration is fine. I just can't maintain that power load for very long.

 

Which does nothing but move the pollution upstream and make it virtually
impossible to accurately calculate MPG.

Sure. Inserting a series of extra energy conversions isn't a typical path to
improved efficiency. Increased efficiency leads to greater MPG.

I'll do nothing of the sort. My point is that car manufacturers have
sidelined innovative gasoline powered automobile improvements by creating
and selling a niche car that in practical terms isn't a big improve at all.
Further, exemplified by the new Honda Accord hybrid, they veil the truth in
a bunch of marketing crapola.

 

Some Canadians are citing 65mpg on the highway in the smartfortwo, which
would seem to be 54MPG US.

Canadians are reporting 88MPG highway with the Insight (73 US MPG).

What would a smart car get with a hybrid option?
An Insight without the hybrid?

 

'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.

Not exactly, but...

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

So simple. They should've kept it.

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.

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 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.

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

 

There's no need for a hybrid option but there is a need for the Smart in the
US.

 

just YOUR opinion. one of the interesting features on the newer prius is
a "thermos" type coolant storage chamber, designed to keep engine
coolant warm long after the car has been shut off.

this aids the GASOLINE engine in cold weather starts, by helping the
GASOLINE engine get to operating temp quicker with fewer emissions, and
can be applied to other GASOLINE engines as well.

oh, dont get all pissy because the japanese are actually spending money
on R&D, while the USA car companies trot out another shitty truck-based
land yacht.

 

or a diesel hybrid insight?

 

FanJet, you obviously know a fair amount, but even more obvious,
your mind is made up You are not going to be swayed by either the
actual data (ex: mpg of Civic Hybrid vs Civic, mpg of Prius compared
to any other like-size and performing vehicle), or by technical
arguments (you haven't responded to my post where I list FOUR ways
that hybrid design improves mpg). You also seem to see
a lot of conspiracies (the above, and auto OEM's "insisting" that
we use 5/20 oil).

As to wall-plug hybrids, I'm pretty sure they come out ahead of the
game in terms of well-to-wheel efficiency. Consider:

Well-to-electric efficiency (US Mix) ~ 41%
Round trip battery efficiency (charge-discharge) 80-90%
Motor efficiency ~85%
Multiply all three for the wallplug hybrid: 28-31%
Compare to a typical ICE on a normal drive: ~20%

Plus the electric is from a variety of sources, not just crude oil,
which is a benefit for "energy independence" (which is a bit of a
pipe dream, but that's another debate).

Yes, there is hype with hybrids. Big surprise, there is hype with
most products and new technologies, both for and against. Yeah, it
isn't a free lunch. But I do think it is quite clear that hybrids
can increase fuel economy by say 20-30% across the board, and often
quite a bit more. Again, at some cost ($, mass, complexity). So
no, it might not be a slam-dunk. But I'd say it is a legitimate
choice and I welcome the increased availability.

 

I've always thought of it as a cruel hoax.

<vbg>

 

Honda would get more than it's worth. A plan would be to wait a couple of
years. If the smart42 turns out to be reliable and we get it in the states,
I'd buy one in a hearbeat.

 

In real-world situations, I think 10% is overly generous but I'll go with
that.

For ICE powered vehicles, this could easily be fixed with computer software,
inexpensive mechanical changes to the engine and a starter motor with real
bearings and an electronic commutator. In fact some Ford Focus engines
already do part of what's needed. In an overheating situation, they're able
to shutdown certain cylinders, turning them into air pumps that cool the
engine.

For ICE powered vehicles this can all be taken care of with improved
transmissions. CVTs and 6 speed automatics are a start.

But performance is sacrificed. The efficiency goals could probably be met
with the suggestions I made. If we don't try, we'll never know. The
incentive for trying would be a more economical, less complex vehicle that
could be sold for a more reasonable price, thus reaching a larger audience.

I say they're not nearly as clear cut as you make them seem.

These things are rightly discussed in cafes at the other end of the
Universe.