converting your car to run on alcohol fuels 1979 - mingle

8/11/2019 Converting Your Car to Run on Alcohol Fuels 1979 - Mingle

1/21

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O;:egon

::,tate .

Untve

rs

Jty

Bun et in No. 56

October 1979

Engineering Exp eriment St

at

i on

Corva l l i s OR 9733 1

. A C ' l s . o N COUNYV U2eARV fSYSfhi

O ~ f 7 M J


2/21

CONVERTING

YOUR

C R

TO

RUN

ON

LCOHOL

FUELS

by

John G Mingle

This

pub

ca

t i on

has been

prepared

by

popular

r eques t

by

' ' do- i t -yourse l fe rs who

wish

to

conver t

t h e i r own

veh ic les

to

run on pure

a lcohol The

reader should

be aware

of severa l

fac t s before

under taking

such a pro j e c t . Th

e re fo re , d iscuss ion

o f fue l proper t i e s a f fec f ing ~ n g i n o p e r a t i on

i s

presented

in

addi t ion to the requi red engine modi f ica t ions .

OREGON

STATE UNIVERSI

TY

Corvall i s ;

OR

97331

OCTOBER 1979


3/21

CONVERTING YOUR C R TO RUN ON LCOHOL FUELS

INTRODUCTION

Alcohol

fue l s

have

been

used for i n t

e rn a l combustion engine

fue l s fo r

many,

many

year s .

Racing engines espec ia l ly can appre-

c i t e

the

high

octane number

and low v o la t i l i t y

of methyl a lcohol

n d

some fore ign

coun t r ies

have

found it to t h e i r advantage to

use a lcohols

in

s tock

engines .

The genera l pub l ic

in the

US has

re 'cen t ly become i n t e r e s t e d

in a lcohols

as add i t ives to , o r corn-

p le t e

replacement

fo r ,

gasol ine in

t he i r

persona l

motor

veh ic les .

The l i ne s a t

se rv ice

s t a t i ons

and the

pub l ic ized

dec l ine in crude

pet ro leum

reproduc t ion

has

prompted t h i s

i n t e r e s t .

There

a r e

two a

l cohol

s

t ha t

may be

used

fo r

i n t e rna l combus -

t i on

engine fue l . The f i r st

of the

whole

fa

m ily o f a lco

hols i s

methyl a lcohol , a l so

c a l l e d

methanol , and

h

as the low

e s t

molecu-

l a r weight

a nd

lowest

bo i l ing po in t .

The second

i s ethy l a lco-

hol , a l so ca l l ed e th

ano l

, t he next lowe s t molecular weight and

b o i l i n g po in t . Methyl a l coho l was formerly des t ruc t ive ly d i s -

t i l l e d

from

wood and, t he re fo re ,

c a l l e d wood a lcoho l .

However,

methanol

i s now made

by

reforming

na tu ra l gas

, bu t it

i s

t

ec

hn i -

ca l l y

poss ib le to

syn thes i ze

it from any c e l lu los i c mater ia l

or

coa l . Ethyl

a lcohol

i s ma

de by

fe rmenta t ion o f sugars

der ived

from f ru i t , gra in , o r any s t a r c h mater ia l .

Indus t r i a l e thanol

i s synthes ized

from e thylene

but

it can be made by

conver t ing

any c e l lu los i c

mate r i a l

to

sugar

and

then

f e

rment ing t he suga

r

in

t he us ua l manne r .


4/21

-

.

. -

Adding

a l co h o l to g as o l i n e

in q u a n t i t i e s

up to

10

anhy-

drous e th y l

a lcoho l

and 90 u n leaded

gaso l ine

i s

now ro u t i n e

and

so ld

commeric ia l ly under t h e

name

Gasohol

. No eng ine

mo d i f i ca t i o n

o r

new

d i s t r i b u t i o n

sys tem

equipment

i s needed.

One p recau t i o n ,

t h a t

e f keep ing w ate r

out

of

the s t o r a g e

and

d i s t r i b u t i o n

system,

w i l l

be

discussed l a t e r .

This publ i ca t ion has been

.

prepared by p o p u la r

reques t

by

those d o - i t -y o u r s e l f e r s who wish to

co n v er t

t h e i r own v e h i c l e s

to

run

on

pure a l co h o l

. However, th e r ead e r

should be aware o f

s ev e r a l f a c t s

before

under tak ing such

a

p r o j e c t .

l

A s p ec i a l l i c en s e i s r eq u i r ed fo r persons us ing fu e l

o t h e r than

g as o l i n e to

prope l

any motor

veh ic l e on

t h e Oregon highways. Records must be k ep t to

show

mi les d r i v en , g a l l o n s o f

fue l used ,

and so u rce o f

fue l . Repor t s

must

be

f i l e d

and t he

seven

c e n t s p e r

ga l lon

roa

J

t ax

pa id .

Reques ts

fo r

forms

and

i n f o r -

mat ion should be d i r ec t ed t o Motor Vehic les D i v i s i o n ,

Fuels Tax Branch, 5821

NE

Glisan , Por t l and ,

OR

97213,

phone (503) 238-8236. Other

s t a t e s

have

s i m i l a r

l aws .

2. Oregon Revised S ta tu t e 483.825 s t a t e s

in

p a r t

as

fo l -

lows:

I t s h a l l be unla-.:.vful fo r any person to d i s co n -

n ec t o r p ermi t

to

be disconnected

a

fac to ry i n s t a l l e d

motor

veh ic l e

a i r p o l lu t i o n co n t r o l d ev ice o r

a

f ac -

t o ry i n s t a l l e d sys tem as def ined i n ORS 468.360,

nor

s h a l l

any person kn

owingly

and w i l l i n g l y

p e rmi t such

a

dev ice o r

fac to ry

i n s t a l l e d sys tem to become o r

2


5/21

remain i n o p e ra t i v e .

T h ere fo re ,

leave c a t a l y t i c

c o n v e r t e r s ,

a i r pumps, exha u s t gas r e c i r c u la t i o n

sys tems, e t c . , in

p l ace and o p e ra t i v e .

Other

s t a t e s have s imi l a r laws.

3 .

I f

your v eh i c l e

i s

new and

still under t h e manu-

f a c t u r e r s . warran ty , you should co n s u l t t h e

d e a l e r

a s

to whether t h e

warran ty

would be vo id i f you

co n v er t ed

your

ca r to run

on

pur

e

a l co h o l .

4.

t should

be remembered

t h a t your

v e h i c l e ' s

engine

has been

des igned ,

deve loped

and

tuned fo r prop e r

o p e ra t i o n

on gaso l ine .

I f

you

change

to some o the r

fu e l it

i s

r easo n ab le to

expec

t some d i f f e r e n c e s in

t h e

e ngine ' s performance

and

ease

o f o p e ra t i o n .

5 .

Oregon

S t a t e U n iv e r s i t y

assumes no

r e s p o n s ib i l i t y

fo r t h e s a f e ty o f

t h e persons under t ak in

g t h e i r own

e n

g i

n e

mo d i f i ca t i o n

and assumes

no

r e s p o n s ib i l i t y

f o r t h e

li f e and performance o f t h e

ve

h i c l e con v e r -

t ed . You, in e f f e c t , a r e an

exper

ime n te r .

In

o rd e r to p rep a re t h e r ead e r fo r th e why o f t h in gs t h a t

a r e

done to th

e e n

g i

n e a s h o r t review

o f

fu e l prop e

rti

es i s

in

o r

d e r .

FUEL

PROPERTIES

BOILING

CHARACTERIST

I

CS

Table 1 s hows some

o f

t h e

fue l

p ro p e r t i e s o f gaso l ine

3

-

.


6/21

anhydrous methyl a l co h o l and anhydrous eth y l a l co h o l .

Anhydrous

.

means

comple te ly

f r e e o f

wate r

. .

t i s

most

imp o r t an t to note

t h a t g as o l i n e is

a

mixture

o f

many hydroca rb6ns f rom n-bu tane

(C

4

H

10

)

to

dodecane

c

12

H

26

.

Many

ca l cu l a t i o n s r e q u i r e

t h a t a

p ro p e r ty

o f g as o l i n e

be expressed as a s i n g l e

number.

In t hese

cas es ,

an

average va

lue

i s e s t i m a t e d

such

a s m o l e c u l a r formula

and

weight .

Also ,

th e r e

i s no s i n g l e b o i l i n g p o i n t t h a t ch a rac -

t e r i z e s

g as o l i n e , s i n ce

it i s a

~ i x t u r o f

d i f f e r e n t

hydrocarbons

each having its

own b o i l i n g

p o i n t .

Th

e re fo re ,

a d i s t i l l a t i o n

curve , shown

in

Fig u re

1 , r ep re s en t s t h e

q u a n t i t y o f g as o l i n e

t h a t

w i l l

evap o ra t e

as

t h e

t empera tu re

is i n c reas ed .

In

con

-

t r a s t , methyl and

e t h y l

a l co h o l a re

both p u re hydrocarbons

and

have

s in g l e

va lues

fo r b o i l i n g

p o i n t s

and o t h e r p r o p e r t i e s .

F i gure

2

shows t h e e f f e c

t

upon t h e d i s t i l l a t i o n curve

o f

add

-

ing

10

and 20 o f e t h y l

a l co h o l

to gaso l ine .

Note

t h a t

it r a i s e s

t h e

curve

b efo re t h e

4

to

6

d i s t i l l e d and

lowers

t h e

curve

t h e r e -

a f t e r .

t i s e n e r a l l y unde r s t o o d t h a t t h e p o r t i o n

o f

t h e curve

f rom t h e 0 to t h e

10 distill

ed

w i l l

a f f e c t t h e engine s t a r t i n g

a b i l i t y and

t h e 1

0 to th

e 50 d i s t i l l e d

w i l l a f f e c t

t h e

warm-up

and a c c e l e r a t i o n

a b i l i t y .

ENERGY VALUES

The energy

v a lu es p e r u n i t

o f

weight

a re most

imp o r t an t . The

engine r eq u i r e s a c e r t a i n amo

un

t

o f energy

to deve lop t h e power

need

ed

to prope l t h e v e h i c l e and

t h e

engine r e a l l y does no t know

f rom

whence

t h e

energy came

.

T h ere fo re ,

if

methyl

a l co h o l h as

4


7/21

8664 BTU's per pound compared to 19000 BTU's

per pound

for gaso-

19000

l i ne

the engine

wi l l

r equ i re (

8664

}

=

2 .2

pounds

o f

methanol

compared

to 1 .0

pound

of gaso l ine to

deve

lop

the

same

power.

This

means

t h a t the

carbure to r

meter ing j e t s must

be

en larged to

de l ive r the g re a t e r amount of the lowe r spec i f ic energy fue l .

OCTANE

NUMBER

There a re

severa l

t e s t s t ha t a re used to determine

octane

number.

The

numbers shovm

in

Table 1 as

Research Octane

Num-

bers a re

determined on a s ing le cy l inder engine ,

opera ted in the

l abora to ry and a r e the

h ighes t numerical

values

o f a l l

the d i f -

f e r e n t t e s t s . Note t ha t there i s some disagreement among

inves-

t i ga t o r s

as

to the ac tua l value for methanol (1}. The road

Blending

Octane

Va

lu

e ,

shown in

Table

1

i s

used to show

how a

veh ic le eng

in

e ac tua l ly responds to

the a lcohol

compared to

th

e

s ing l e

cy l inder l abora to ry

engine.

For

exam

p l

e ,

cons ider

a

10

me thanol /90 % g s ~ l i n blend; the 10% gasol ine t ha t i s rep l aced

had a v

l ~

c

9.3

octane

numbers bu t

the

10

% methanol added had

a

value o f 13.5 octane numbers,

the re fo re th e

blend gains 4.2

o c t

ane

numbers.

MIXTURE

RATIO

The

a i r - t o - f u e l

r a t i o

i s

the

most c r i t i c a l i tem

to

regu l a t e

with regard t o exhaust emission s and fuel

economy.

The

chemi

-

ca l l y cor rec t

a i r

- fu

e l r a t i o may

be calc

u l a ted by knowing the

molecu lar formula and weight of the fue l and wri t ing an equat ion

which presumes t ha t a l l the

carbon i s

oxidized

to

carbon

dioxide

5


8/21

C0

2

) and a l l the hydrogen to

w ~ ~ r

H

2

o)

.

Referr ing

to Table

2,

t may

be

seen t ha t the chemica l ly

c or r e c t

a i r - f u e l r a t i o i s

14.96

fo r gaso l ine ,

6.47

fo r

methanol

and

9.01

fo r

e thano l .

I f

t he engine

wi l l

a sp i r a t e a

f ixed

amount o f a i r a t any p a r t i c u -

l a r t h r o t t ~ opening, then the carbure to r must meter a

sp e c i f i c

amount

of

fue l to provide the c o r re c t a i r

- f u

e l r a t i o .

Thus,

compared

with gaso l ine ,

the

c a r ~ u r e t o r must

d e l i v e r : : ~ ~

=

2.31 t imes more

methanol .

This

.r a t i o

i s

s l i g h t l y

g re a t e r than

t he

r a t i o

2.2) based

on

energy va lues .

VAPORIZATION REQUIREMENTS

Table

1 shows values fo r

the

l a t e n t hea t o f vapor i za t ion .

These va

lu

es r ep resen t the amount o f hea t energy t h a t must be

suppl ied to evaporate one pound o f fue l . Note t h a t methanol

.

474

3 36 . h

f

d

f

equ1res

141

=

t1mes

t e

amount

o energy

requ1re

or gas-

o l ine .

As

shown

prev ious ly

2.3

pounds

o f

methanol

a re

requi red

compared

to

1 .0 pounds o f

gaso l ine

fo r

a chemical ly cor rec t mix-

tu re ,

t h e r e f o r e

the

t o t a l

add i t iona l energy to evapora te metha-

nol in the in take manifold i s 2.3 x 3.36) = 7 .7

3

t imes the

amount

to evaporate

the chemica l ly

c or r e c t mixture

o f

gaso

l i n e .

This add i t iona l

energy

must

be suppl ied

by hea t ing the i n t ake

manifo ld

with exhaus t gas o r r a d i a to r water 2) .

SOLVENT EFFECTS

Al l hydrocarbons

are so lven t s to some degree . Therefore ,

t i s not supr i s ing to f ind t h a t methanol i s a

good

so lven t fo r

some

p l a s t i c s

and

e las tomers as wel l as being

cor ros ive

to some

6


9/21

meta l s such

as

aluminum, lead , magnesium and t i n 1) .

Because

the

composi t ion

o f p l a s t i c s and e las tomers i s so d iver se ,

it

i s

not with in

the scope of t h i s

wri t ing to do o ther than

advise

the

r eader and

po te n t i a l

user

o f methanol to

be a l e r t for these

so lven t

and

cor ros ive e f f e c t s . One

approach

i s to disassemble

the ca rbure to r and fu e l

pump,

immerse

a l l

the

par t s in methanol

fo r some extended pe r iod , say 3 o r 4 days,

then

check for any

change

in

dimension, t ex tu re , o r co lo r . Ethanol

appears

to have

ne g l ig ib l

e so lven t o r corros ive e f f e c t s on fue l

s ys t

em mater ia l s

except when water i s

presen t .

W TER

TOLER

NCE

Both methyl and e thyl a lcohol are misc ib le in water in a l l

percentages . Gaso l in e and both alcoho l s are misc ib le

in

a l l

p

ercentage

s

as long as

the re i s no water

presen t . The

presence

o f

only

0 .1

to

0.2 water

w i l l

cause

e

i t h

e r

m

e t

hyl

o r

e thy

l

a l c o -

hol mixed with gasol ine to separa te . (4) 1) . Therefore

if

e i the r

methyl o r e t h y l

a lcohol

i s

to be

mixed with gaso l ine ,

it mu s t be

anhydrous

and

ll

t anks

i n to

which

it

i s to

be

mixed o r s tored

must a l so be . f ree

o f

wate r .

Th

e caps on t anks , b

a r

r e

l s and

cans

should b e kep t

c losed

as wel l as tank ven ts being

equipped

with

dryers to

preve

n t the

a lcoh

o l

from absorbing

mois tur

e

from

the

a i r .

Alcohols

may be

purchased

in

severa l

d i f f

e

r e n t

grades depe

nd

-

ing

on

the

p u r i t y and wa t e r con ten t . Pur i ty i s t he l e a s t impor-

t a n t

because the impur i t ies a re

most l i ke ly

to

be

combust ib le

7


10/21

--------------------------------

hydrocarbons.

Water and

e thy l

~ l c o h o l may be sep a ra t ed by d i s -

t i l l a t i o n except

fo r the

l a s t

5

water

which

i s

in the form o f

an

azeot rope

with

the

e thyl alcoho

l

and

must be

separa ted

by

another

process . 200 proof e thanol i s the anhydrous grade mean-

ing complete ly f ree

o f

water . 190 proof i s 95 alcohol

and

5

water

in

the form o f an azeot rope

. Proofs below 190 have

excess

wate r in additi

on

to the

azeotrope.

I f

the a

lc

ohol

i s

to be

used as t he whole fue l ,

some

water

can be

t o l e r a t e d be fore the

carbure to r meter

i

ng

i s

too

l ean .

TOX ICI

TY

All a lcohols

are toxic

i f

t aken i n t e r n a l l

y .

However, METH

-

ANOL IS ESPECIALLY TOXIC AND UNDER NO CIRCUMSTANCES

SHOULD

IT

BE T

AKEN

INTERNALLY--BLINDNESS

AND DEATH MAY

RESULT .

Ethanol

i s the potable

a lcohol

when

included

in

beverages

bu t i s dena -

tu red for indus t r i a l

use

wit h h igh ly t ox ic f lu ids such as meth-

anol , gaso

l in

e methyl

i sobu ty l

ketone pyrona te ,

o r

ace ta ldo l

6). Therefore DO NOT DRINK INDUSTRIAL ETHANOL. The e f f e c t s

o f pure

a l cohols

on

human t i

ssue

a re burning, dehydra t ing and

degreasing.

It

i s no t advised to use a l coho l s as

so lven t s

fo r

c lean ings hands,

e tc .

ENGINE MODIFICATIONS

VOLATILITY

Th i s term

deno

t

es

the eva

pora t ion

c h a r a c t e r i s t i c s

and are

impor tant fo

r

s ta rt

ing the

engine

acce

l e r

a t

i

on

w

arm up and

cran

k

case

d i

l u t io

n, as

wel l

as ca rbure to r i c ing

and

v p ~ r lock .

8


11/21

S t a r t i n g a co ld engine r equ i res

opera t ing

the choke on the c a r -

bure to r the purpose o f

which

i s to

supp ly , fo r

a few seconds,

about

t en

t imes

the

normal

amount

:

o f

fue l .

I f

t en

pe rcen t o f

the

l i qu id

f u e l

wi l l evaporate

in the in take

manifo ld ,

then a

combus t ib le mix ture

o f

fue l and a i r w i l l

reach the

cy l in d e r s .

Gasol ine conta ins

about

6

to

10 n-

butane which

has a

bo i l ing

0

p o i n t o f 31 F and

wi l l evaporate

read i ly in

the in t ake

manifold

thereby p rov id ing the necessary combust ib le

mixture

. .

Pure

a lco -

h

o l s

b o i l

a t

e leva ted

temperatures

and

evapora t ion

a t

low

tern-

p e r a tu r e s

i s very slow. Th

e re f

ore

hea t energy i s ~ e e d e d to

cause the

evapora t ion to

occur

quick ly and t he

most

appropr i a t e

p l ~ e to

supply

t he hea t

i s a t

the

f loor o f

th e i n t ak e manifold

immedia te ly under t he carbure to r . t .has been shown by t es t s

conducted a t OSU

t h a t a

small

e l e c t r i c wa

t e r h ea t

e r i n s ta l l e d

in

th

e

engine

coo l ing

water

c i rcu it

wi l l

supply the

necessary ener

-

gy

e sp e c i a l l y i f the eng in

e design i ncorpora t e s a

water hea ted

i n t ak e manifo ld .

The smal l

h ea t e r

s a re so ld commercia l l y and

a re popular fo r use

in subzero

clim a

t e s

to s t a r t

engin

e s even

when using gaso l ine . OSU t e s t s showed t h a t

a f t e r

20 minutes

hea t ing the engine would

s t a r t on methanol when t he ou t s ide

a i r temperature was 20F.

t

should

be poin ted

o u t

t h a t no

s t a r t i n g

a id

i s

requ i r

e d

if

the

a i r

t empera tu re i s

above

about

Due to

th

e var i e ty

of

engine des i

gns

it i s beyond the scope

o f t h i s w r i t i n g to give exac t i n s t a l l a t i o n i n s t r u c t i ons . How-

ever

the e l e c t r i c

he

a t e r shou

ld

b e i n s t

a l

l ed so t h a t

its

h

o t

----

wa

t e r i n l e t i s d i r e c t

ed as c lose to the in take man i fo ld

as

poss ib le .

9


12/21

Innova t ion

may be r equ i red on some

eng ine

des igns . The

popular

l i t e r a t u r e has r epor ted

t ha t an

e x t r a windsh ie ld c leaner

water

system

conver ted

to

s to r e

.

and

s q u i r t

gaso l ine ,

with

t he

nozz le

i n s t a l l ed i n the

in take manifold

j u s t below

the

ca rbure

t o r wi l l provide an a l t e rna t e

fue l

cold s t a r t i n g

system.

Also

anyone fami l i a r with s t a r t i n g i ~ s e l engines

in cold

weather

may

poss ib ly adapt

h is own

ideas to s t a r t the

engine on

a lcoho l .

As descr ibed e a r l i e r ,

add i t fona l energy

must

a l so

be sup-

p l i e d to

the in take manifold

to vapor ize

the

a lcoho l ,

even

with

a

fu l l y

warmed up

engine dur ing

per iods

o f prolonged acce le ra

t i on

o r h i l l cl imbing

when

the maximum amount o f fu e l

i s

being

metered by the ca rbure to r .

Tests a t

SU have

shown t ha t

winding

~ i nch diameter copper tubing around

the

i n t ake

manifo ld

runners

( indiv idual

l egs

o r

pipes

to each cyl inder) and c i r c u l a t i ng hot

r a d i a to r water through t he tub ing wi l l

fu rn i sh

the evapora t ion

energy.

The

hot water i s e a s i l y

obta ined

from the

v e h i c l e s

hea te r hoses but care must be t aken to assure cont inued f low

even when the veh ic le hea te r i s shu t of f . The

copper

tub ing

should

be wound as

t i g h t as poss ib le to give

good

meta l to metal

con tac t

fo r hea t t r a ns f e r and the

co i l s

should be touching

each

o ther . The bes t

i n s t a l l a t i o n

of

copper

tub ing

would be

the one

t h a t

l eaves

very

littl

exposed

su r face of the

.

manifo ld

runner .

HIXTURE RATIO

Diffe rences

in th

e

chemical ly

c or r e c t a i r

to fue l r a t i o

between gaso l ine and the

a lcoho ls ,

shown in +able 2 and d i s -

10


13/21

~ . . . . .

cussed

e a r l i e r , r equ i re

t ha t t he m

t e r i ng

j e t s

in the

carbure -

t o r be enla rged.

Table

3 shows

the method

used for

ca l cu l a t i n g

t he r a t i o by which

the

gasol ine j e t

d i ~ e t e r

must be mul t ip l i ed

t

to

ob ta in th e proper

a lcohol j e t

diameter . For

methanol the

r a t i o i s 1.50 and for

e thanol

the r a t i o i s

1.27.

Carbure tor

j e t s are marked

by

numerals represent ing the d ia -

meter

o f

the

o r i f i c e .

For

example, in engines

manufac tured

to

Engl i sh un i t s , a number o f 47 would r e a l l y mean

0.047

inch

in

diameter .

In metr ic un i t s , a number 120 would

r ea l l y

mean

1.20

mi l l ime te r

in

diameter .

For

example, to f ind

the

new j e t d ia

meter fo r methanol use , mult ip ly

the

above numerals found

on

t he gaso l ine j e t by 1.50 which

gives

0.071 inch

in

Engl ish un i t s

and

1.80

in metr ic un i t s .

Figure

3 shows t he

c o r re l a t i o n o f

the

Engl i sh

and me tr ic un i t s

with

the

s t ee l w ire gage d r i l l

s izes

in -

d ica ted

on

the c o r re l a t i o n l i ne . The neares t d r i l l s iz e to

the

new

~ i m e t e r

i s

a

No.

50.

t

i s

recommended t h a t

a small

h i

gh

speed prec i s ion

d r i l l

s ta

nd

be used

with a v-notch

d r i l l press

v ice

holding the

j e t . Grea t care must

be

t aken

to

in su re proper .

a l ignment o f t he new d r i l l

and

t he ax is o f the old hole .

The designs

o f

the many

makes o f

carburetors are

so

va r

i

ed

t h a t i t

i s

b

eyond the

scope o f

t h i s

wri t ing to gi ve more

spec i

-

f i e d e t a i l s . owever , most carbure to r s have one o r more i d l e

j e t s , one o r more

primary j e t s and

one o r more secondar y j e t s .

A

shop

o r overhaul manual fo r your

vehic le should

be

consul t e

d

to asce r ta in t ha t a

ll

th e

j e t s

are

accounted fo r and enlarged by

the same

r a t i o . Do not a l t e r

the a i r -b l eed

j e t s and do mainta in

11


14/21

t he

recommended l i q u id l ev e l

in the f l o a t bowl. The

v a r i ab l e

i d l e mixture

need le ne

e d not

be a I ter

ed b u t it

may

need

ad ju s t

ment a f t e r the engine has

been

s t a r t e d .

SPARK

DV NCE

ND COMPRESSION RATIO

Pure a l co h o l s have very high octane numbers as shown in

Table 1 and discussed

e a r l i e r . This h i g h e r

oc tane number

t han

gaso l ine) may

be u t i l i z e d

by advancing t he b as i c

i g n i t i o n

t iming

and y

i nc rea s ing the compression

r a t i o .

R.

J . Nichols

(5)

has

descr ibed

t e s t s

made on an engine

ope ra t ing

on p u re methanol mod-

i f i e d

with

s p ec i a l p i s t o n s

and

camshaf t

where

t he

compress ion

r a t i o was r a i s ed

to

1 3 9 ~ 1 Tes t s a t

OSU

have sh?wn t h a t whe n

ope ra t ing on pure

methanol

with t he s tandard 8 .0 :1 compression

r a t i o changing t he ba s i c i g n i t i o n t iming

from

6 BTC

to

15 BTC

i nc rea sed the

p a r t t h r o t t le fue l economy about 10 and i n c reas ed

t h e f u l l t h r o t t l e p owe r a t high eng ine rpm ab o u t 15 .

This

h e

lps

reduce the

mi les

per ga l lon p en a l t y a s s o c i a t e d w i t h p u re a lcoho l

corrLbustion.

There i s a l i m i t t o the amount

o f

i g n i t i o n advance an

engine

\v i l l

t o l e r a t e

even

i no combust ion knocking i s heard / and t h i s

l i m i t may

be

found by

e xperiment .

Begin w i t h

a

modest advance o f

. 0

say 4

and

1

using a s top watch, t ime a f u l l

t h r o t t l e acce l e r a t i o n

in

high

gea r from 30 to

55 mph.

0

Advance t he t iming by 4 and

t ime t he acce l e r a t i o n from 30 to 55 mph

aga in . Repeat the proce-

dure

u n t i l t he minimum

t ime f o r

t he a c c e l e ra t i o n

i n t e r v a l

i s

ob-

t a ined.

The i g n i t i o n t iming

fo r th e

minimum a c c e l

e r a

t i o n

t ime

i s the o pt imum t iming .

12


15/21

SUMMARY

For convers ion

to

opera t i on on

methyl alcohol :

1 . Determine t h a t

none

o f t he p l a s t i c and

e las tomer

pa r t s i n

t he

f u e l

system w i l l

d isso lve

i n methanol .

2 .

Enlarge

a l l

ca rbu re to r meter ing j e t s by th

e r a t i o

o f

1 .5 t imes t he j e t

diamete r

fo r

gaso l ine use.

3 . Provide hea t

energy to

the in take manifo ld

for

s t a r t -

ing

and f u l l

t h r o t t l e

a c c e l e r a t i o n .

4 . Drain t he fue l

system

o f all gaso l ine and make s u r e

syste n.

i s

rolo: : :> n

::>'nrl

r : ~ . . . . .

~ --

- - . z

5. R e f i l l

wi th m

e t

ha nol , s t a r t

engine

and adjus t i d l e

mixtu re and

i d l

e speed . wh e n engine i s warm.

For

convers ion to op

e

r a t e

o n e thy l a lcohol :

l En la rg e t h e c a r b u r e t o r meter ing j e t s

by

the r a t i o

o f 1 .27 t imes th e j e t d iameter fo r gaso l ine use .

2.

Provide h ea t

energy

to

t he

in t ake man i fo l d

for

s t a r t i n g

and

f

u l l t h r o t t l e a c c e l e r a t i o n .

3 .

Drain

f u e l

system o f all gaso l ine

and

make

c e r t a i n

sys tem i s c lea n a nd dry .

4.

Ref

ill

with

e t

hano

l

start engine and a d j us t i d l e

mixture and

i d l e

speed when engine i s warm.

13


16/21

SELECTED REFERENCES

'

.

l

Ingamel l s ,

J .

c.

and

Lindqu i s t ,

R.

H.,

"Methanol

as

a

Hotor Fuel o r a Gasol ine Blending

Component ,"

SAE

#750123, Feb. 1975.

2: GM

Research

Labora to r i

e s

Search ,

Vol . 12,

No.

l

J an . - F eb . ,

1977.

3 .

4 .

5 .

6 .

U.S. Energy Research and Development Admin i s t r a t ion ,

"Ch

a r a c t e r i z a t i o n

and

Re

s

ea rch

o f I

n v es t i g a t

io

ns o f

Methanol and Methyl Fue l s , F ina l Repor t EPA Grant

No. R 803548-01 , CONS1258.

",Alcohols

and Hydrocarbons as

-1otor

F u e l s , SAE Spec ia l

Pub l i ca t ion ,

SP254,

June

196

4 .

"Alcohol Fuels T ~ c h n o l o g y , Vols .

l 2

and 3 , Third

I n t e r n a t i o n a l

Symposium,

Asi lomar

, C , May 1979.

U. S. Department

o f Energy,

"Denatura

n ts f o r

Ethano l /

Gasol ine

Blends ,

HCP/m 2098-01, Apr i l

1978.

14


17/21

TABLE 1. FUEL PROPERTIES

Molecular Formula

Molecular Weight pounds per

mol)

Sp e c i f i c We i ght pounds per ga l lon

Boi l ing Poin t , F

Lower Heat ing

Value BTU/

pound)

Research Octane Number

Road Blending Octane Value

G

]

(

1

aso

.1ne

6.2

31-421

19,0 00

9 3 (

2

)

Latent

Heat

of Vaporizat ion BTU/pound) 141

Note:

Methyl

Alcohol

Ethyl

A

l cohol

CH

3

H

c

2

H

5

0H

32

46

6 .6 6.5

149 172

8 ,664

11,604

106-115

107

.

135 120

474

361

1)

Gasol ine

i s

a

heterogenous mixture

o f

hydrocarbons

from

c

4H

10

t h ro

ugh

c

12

H

26

.

The

values

shown are average values

used fo r com

p u ta t io n s .

2) Unleaded

i

i

i

I

I


18/21

A/F

A/F

T BLE

2.

STOICHIOMETRIC

AIR-FUEL

RATIO

GASOLINE

= 12.25

x

4.76)mol

mol

fue l

a i r

X

29 lb a i r /mol

m

113

lb

fue l /mol

m

METHYL LCOHOL

=

1.5

x

4.76)mol a i r

x

29

lbm

a i r /mol

=

mol

f u e l 32

lbm

fue l /mol

ETHYL LCOHOL

=

14.96

6.47

A/F = 3 X 4.76) mol

mol a i r

a i r

29 lb a i r /mol

m

x

46 lb f ue l /mo l =

m

9 01


19/21

..

TABLE

3.

CARBURETOR

METERING JET ENLARGENENT

For Pure

Methyl Alcohol

A

=

J e t Area for

Methanol

Operat ion

meth

A

gaso

=

J e t Area fo r

Gasoline Operat ion

Ymeth

=

Spec i f i c

Weight

o f

Methanol,

lb / ga l l on

m

y

=

Spec i f i c

Weight

o f

Gasoline ,

lb

/g a

l l on

gaso

m

(A/F)meth

=

Stoichiometr ic

Air-Fue l

Rat io ,

'1ethano l

(A/F)gaso

=

S toichiome t r i c

Air-Fuel

Rat io ,

Gasoline

(A/F)meth X

Ameth

X

/ymeth

=

(A/F)

X A X /y

gaso gaso gaso

6.47 X Ameth X =

14.96

X

A

X

aso

A =

meth

14.96

X

6.47

16 20

X

A

16 60

gaso

= 2.31

X

0.97

X A

gas

o

=

2 24

gaso

J e t Diameter Meth = 1.50 J e t Diameter

Gaso

.

For

Pure Ethyl Alcohol

A

=

e thy l

14.96

X

9.

01

*

*

16:20

X A

16:54

gaso

*

*

=

1.66

X

0.974

X

A =

1.617

A

gaso gaso

J e t Diameter Ethyl = 1.27 J e t Diameter Gaso


20/21

450

400

v

350

.

JOO

w

cc

250

:>

cc

200

Cl

::E

w

t 50

tOO

i

/

~

_)./[

sryt l i l rhol l

Vi

I I

1/

I

Ethyl

Alcohol

IL

Me thy l Alc ohol

0

o

to 20 JO

40 50 60 70 eo so 100

FUEL EVAPORAT

EO -

Percent

( Li cMy

E

Ziuryt l

Fig.

1 - ASTM

distillation curves

for

gaso

l ine

and

a lcohol

J92

200

ISO

J20

160

284

;> 140

.

..;

w

248

~ 1 2

...


21/21

I

I

l

14

converting your car to run on alcohol fuels 1979 - mingle

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