Evening star., 1960-07-29
Clearing the Air


clearing the air is indeed
highly commendable, the
approach that is being taken
in the current anti-smog
campaign leaves me more
than a little skeptical and
even a bit apathetic.
L make no claim to knowl-
edge in automotive engineer
ing or smog control. Yet I
feel compelled to express
some concern because it ap-
pears to many people that a
big production is being staged
about "blow-by" in new pas
senger cars while the OBJ
noXiouS exhaust of Wash
ington's Diesel powered
transit system and the
stencil and smudge generated
by our suburban backyard
pyromaniacS seem to go
totally ignored.
"Blow-by," according to
my understanding, refers to
gases that leak through pis-
ton ring clearances and on
out into the air, usually by
way of a vent pipe in the
crankcase; exhaust" the
major part of the waste
product, leaves by way of
open exhaust ports,
the muffler and tailpipe. I
concede that there may be
slight chemical differences
between the two, because
blow-by is released during
the fuel-burning process.
whereas exhaust is released
afterward. Nevertheless, the
sheer volume of exhaust
gases leads me to believe that
blow-by gases must be but a
minor part of our troubles.
Further. the newer the car,
the less significant the blow
by-for two reasons. First
with pistonS, rings and cylin-
der walls unworn, the seal
against blow-by is virtually
complete. Second, the later
models of cars can be ex-
pected to remain blow-by
free longer than before, be-
cause modern methods and
materials permit ever tighter
and longer lasting piston ring
seals. (Those who accuse the
automotive industry of not
giving a hoot about air pol
luton may well be right. But
piston ring leakage is costly
IN compression and economy,
and there can be no doubt
that Detroit is against it,
I would guess that most of
the passenger cars seen on
the streets are making a
single trip to and from work,
shopping. or some other ap-
pointment and thus are in
actual use for only a small
fraction of the time, while
buses, trucks, taxicabs (and
the backyard pyromaniacs)
go on and on and on.
So the attack on 1861 cars
seems to be directed against
only very minor part of even
the blow-by problem, and
this problem. itself, is but a
minor part of the automobile
caused pollution, and private
automobiles (at least on my
own scale of obnoxiousneSs)
are insignificant in compari-
son with the buses and
trucks.
quote a question used in
many connections by the late
DR., Wenner of the National
Bureau of Standards: Aren't
we meticulously weighing the
flea while we neglect the
weight of the elephant?"
L. +. Richtmyer.
-
I read with interest your
articles on auto exhaust
fumes and heartily agree that
something should be done
about this menace. But why
are all the articles seemingly
directed toward the private
auto? The greatest amount of
noxious gas fumes comes from
those roaring behemoths, our
Transit Co. buses. Everyone
who has followed a bus knows
this. They run past my home
and the air is so bad I can
not have my front windows
open early in the morning as
the fumes from the constant
parade of buses is enough to
cause nausea. And why are
the buses allowed to run with
squealing brakes and back
firing motors? We have (or
had) anti-noise regulations
But these, like many others
are now mostly ignored.
George c. DeSpe.