TOM WALSH: Chrysler gears up to use criticism to solve sho..

"Joe Pfeiffer" <pfeiffer.TakeThisOut@cs.nmsu.edu> wrote in message
news:1blk0y80bl.fsf@snowball.wb.pfeifferfamily.net...
> "Road Runner" <cfrancis36.TakeThisOut@cogeco.nospam.ca> writes:
>
>> Most hybrid vehicles recharge the batteries by way of regenerative
>> braking,
>> making use of the electric motor as a generator to recharge the batteries
>> and slow down the vehicle instead of using the brakes and wasting the
>> energy
>> to generate heat. Hybrid cars are most efficient and economical in city
>> stop
>> and go driving, the gas engine hardly ever runs, batteries stay charged
>> and
>> brakes last forever.
>
> And the laws of thermodynamics have been repealed, apparently.


The laws of thermodynamics are the reason hybrids work. Energy is not
created nor destroyed but changed from one form to another (1st law). It is
not 100% efficient and as I previously stated, the gas engine (ICE) hardly
ever runs. The electric motor is very high in efficiency unlike an internal
combustion engine and produces maximum torque at 0 rpm. Ideal for starting a
vehicle from a stop and low speed operation with no pollution .

"Bill Putney" <bptn RemoveThis @kinez.net> wrote in message
news:6c73cnF3ev8lfU1@mid.individual.net...
> Joe Pfeiffer wrote:
> > "Road Runner" <cfrancis36 RemoveThis @cogeco.nospam.ca> writes:
> >
> >> Most hybrid vehicles recharge the batteries by way of regenerative
braking,
> >> making use of the electric motor as a generator to recharge the
batteries
> >> and slow down the vehicle instead of using the brakes and wasting the
energy
> >> to generate heat. Hybrid cars are most efficient and economical in city
stop
> >> and go driving, the gas engine hardly ever runs, batteries stay charged
and
> >> brakes last forever.
> >
> > And the laws of thermodynamics have been repealed, apparently.
>
> You undoubtedly are referring to the unavoidable percentage losses every
> time energy is shuttled from one form to another, Joe. The proponents
> would argue that recovering 25, or 40%, or whatever the number is, of
> otherwise wasted energy is better than throwing it all away as heat into
> the brakes.
>
> But I share some of your skepticism, and have stated on this ng before
> that I can't help but feel that if you take the same under-powered
> gasoline engine they use in the hybrid and put it in the same car
> without all the controls complexity and added weight of batteries and
> motor/generators that you wouldn't achieve similar mpg simply because
> that gasoline motor is small and optimized for efficiency. The only
> "extra" you would then get out of the batteries and motor/generators (in
> spite of their added mass) is acceleration levels when needed that that
> underpowered gasoline engine can't provide on its own.
>
> IOW (with the exception of the acceleration issue) the batteries and
> motor/generators are possibly nothing but smoke and mirrors - someone
> should do an experiment and strip all that excess baggage (mass and
> complexity) out and see how the car does for mpg with nothing but the
> same gasoline engine powering it.
>

Bill, there's 2 tricks here that comprise the primary smoke and
mirrors:

1) IF the ICE is designed as a constant speed engine (most hybrid
designs are not) then a LOT of efficiency can be picked up from the
use of tuned intake and exhaust runners and headers. For that matter
they really ought to pull the old 2-stroke designs out of the closet
since when those engines are run at their tuned RPM they are -very-
efficient and non-polluting. Generators, also, are much more efficient
when run at a constant rpm.

The gains at running the ICE at a constant RPM outweigh the conversion
losses.

2) City driving is almost always 35Mph or under, thus wind resistance
is almost negligible. Imagine for a moment if the EPA ran it's MPG tests
at 30Mph instead of 55 or 60Mph. It would add at least 10 mpg to
every vehicle out there probably much more.

There are hypermilers who have worked out really impressive MPG gains
in city driving with regular cars by using the engine as a brake whenever
possible and hardly touching their regular brakes.

Of course, if all city drivers did the kind of driving that a city-running
hypermiler did, cities would be hopelessly gridlocked.

Ted