Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1920-09-19
s|MPL|F|ED LESSONS IN
CARE OF AUTOMOBILE

CARE III RUlUMUblLE
Engineer GucTrlich Continues His
Lecture OH Operation of tho
Carbureter.
Copyright, 1917. by Frederick
G. Guerrlich.)
Lecture No. 2fO.
1t was shown in tho last lecture
thit rs the engine was spccded up the
mixture became richer. 80 that some
uevice to automatically make the
In most carhurctcrs this is done BY
valve. which works, automatically.
you will note is held against, its
seat BY the spring ~" the. pressure
o. which can na,,o be adjusted by the
~ &C." it must also 'oe In the space
"" and under the valve H." Now.
vacuum means an air pressure less
than that of the atmosphere. ana a.
tho atmosphere is on top OF the valve
n" the pressur. ON top of IL viii be
greater than under it. and i, would
Let VIZ suppose that the spring $50
t. adjusted 80 that Its pressure would
just hold the valve closed against the
pressure OF tho atmosphere when the
engine is moving slowly. What would
happen when the vacuum in w. is In
creased as i Will b: when the en-
I'll" will open. as the spring Is not
strong enough to hold il ciox,I
against IN. additional difference in
~ sSurc between the atmoBphcre aud
rc vacuum: thus extra air viii enter
We mixing chamber. and 80 bring the
.~'urc back to the right proportion.
n" Cher The Speed, the farther the
So "l!l open. ana the more air
ne auxiliary valve II" is adjust
10 Gpr tho low speed and will opon so
10 give pretty nearly the right
giSturc for the higher speeds. but
because Of tho variations in the
yin not, always be exactly right Tor
f'ah or too Weak For 'p ri. re reason 80"
most carhurcteIs. in addition 10 low
spcci adjustment. In some this is
connection with the auxiliary valve.
The nozzle needle wlth tho throttle
lever. Different makes OF caraurcters
"ii! be studied at IA later date.
MIKE spray Fine.
Al carhu!e'e- makers try 10 have
,h. spray na fine AS posi- BILE. ~ the
nearer 10 mist IT leaves the nozzle
gaseous state.
~ saw In n previous lesson that
tho volume OF tho gasoline sprayed
made smaller. We also cav that /;
would increase as tho vacuum is in
creased; thus. If We could increase
.s nac"um: sc cHpId maS. the mole
amount of gas. and have |; finer. TO
incrrhs" the vacuum Al tho nozzle.
What - known - a Venture Tube.
O. Is often built into the car burrtnr.
Have you ever stood on railway
platform anu noticed tho suction Of
fast train as IT, PUSHES past? This
suction ~ AN Indication that there Is
"a varuum Immediately behind the
Train II the train. instead OF rushing
through IN" air, stood atiiI. and the
air rushed past II. there would be the
came vacuum behind the last car.
Tic same thing happens in the car
81 hITrtrr. AZ you VIII not that you
could regard the nozzle as the train
OF ears. AS the air PUSHES past the
~. &c " viii take the course SHOWN by
tp.tcd lines. ana ;h"rc Viii bn 4
'c-, * which VIII he vacuum.
YOU will notice that there Is \
nrn "a: the nozzio Ia addition to
of the engines suction. or
,isSc the faster the air travels the
sreaicr VIII be his vacuum. This is
'-lcr with the higher engine speed.
IrIr!ns tho auxiliary air valve.
Now, II We could increase the speed
'ns air az 1t passes the nozzle. tho
pt"c IL" or vacuum. could he In
.SrA and 20 the noZrle opening
hG inado smaller and stiil give
same amour, OF gas. The Ven
Tube wlli make the air move
er al the nuzzle.
and in about the same time.
.Jt the opening at IL only about
ni ~ tina; at and ]. and so
or tac saine volume or amount OF
" a. pass - passes and
ace. say a minute. Il will have TO
IAN see n"~ the Nentur! viii ac-
pmplisn ltT purpose OF giving fine
pray
Condemnation De.crib-d.
previously told you that the liquid
gasoline 49, Grange 10 a vapor nt a
temperature Of about 20 degrees. the
-anc as water v ~ turn to steam at
temperature OF @l2 degrees. when
I'D steam strikes Il surface co!de.
Nan .ia degrees it viii condense and
gain become water In the SANE
rINcs cold surface IT Will con-
tense.
Tnr above is the reason why II Is
lard TO start on cold da:. While
nc carburc;er Will do lis work prop
rly. the vapor. however. on the way
o the cylinders. strikes the cold man
old and so condenses. With the re-
carhcs the cylinders. When tnc en-
me is criakcd il really travels very
.owly and so the suction. and the
movement OF the mixture is slow. thus
acreasng the chance for condcnsa-
What can we do TO start In cold
,catacr? II. when surfing. VIC make
he mixture very rich. then even
|hough most Of the gas coMdenscs or
he way to the cylinders. the chances
ra that enough will reach them to
ausc an explosion. The explosion
III make the engine rcvolvc fast.
ausinG a quick suction, and a quick
iovcment Of the mixture. thus not
wing the gas u chance TO condcnse
OF only that. but because of the
|riciion between the previously con-
leased gas and the tast-movIng air,
ne condensed gasoline. which is on
he manifold. Will he made TO travel
the direction OF the cylinders and
get into them. where. the temDera-
ure being high from the former ex-
loSon. II VIII vaporize again.
To enrich the mixture when start
NJ, sometimes the carbureter ia
coded by holding down the float, hut
erhaps more often much of the air
chOkeG off by means Of choke
awe. This valve is operated by a
ire fastened to a rod or lever. either
the instrument board or steering
ylulnn. when Il self-starter is. FUR
ishcd. or by wire which passes
trough the radiator and terminates
small ring or hook, when the
hSne is cranked by hand ''E"'
lows the choke valve.