Medical Society of the State of North Carolina. An.

Cyclopedia of automobile engineering; a general reference work on the construction, operation, and care of gasoline, steam, and electric automobiles, instruction in driving, commercial vehicles, motorcycles, motor boats aerial vehicles, self-propelled railway cars, etc online

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Online LibraryMedical Society of the State of North Carolina. AnCyclopedia of automobile engineering; a general reference work on the construction, operation, and care of gasoline, steam, and electric automobiles, instruction in driving, commercial vehicles, motorcycles, motor boats aerial vehicles, self-propelled railway cars, etc → online text (page 21 of 27)
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of passages bored through it, and by its heat converts the fuel from
a liquid to a ga.s.

The engine is a two-cylinder, vertical, compound, condensing
type designed to work at about 600 pounds pressure to the square


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inch. Its working parts, consisting of the crank shaft supported on
large annular ball-bearings, pistons, connecting rods, crossheads,
valve mechanism, and pump levers, are shown complete in Fig. 106.
The valves are driven directly from the connecting rods by what is
known as the Joy type of valve gear, the valves themselves being of
the piston type. Steam is admitted through the center of the valve
and exhausts at its ends; as the pressure is the same on all sides,
a negligible amount of power is required to operate the valve. The
crank case is made in one piece, access to the moving parts of the
engine being had by large handholes, normally covered with light
plates. The side plates are shown m Fig. 107, there being a third
large plate on the bottom of the crank case. The engine is supported
on two cross members riveted to the main frame and is so hung that
the driving shaft is perfectly horizontal. As there is neither clutch
nor transmis.4ion gear, the drive is direct and positive from the engine
through the long driving shaft to the rear axle.


While the achievement of a degree of reliability that would per-
mit it to compete with other forms of transportation was the first deter-
mining factor in the history of the development of the commercial
vehicle, it is needless to add that the influence of greatest importance
bearing upon its general adoption is cast of operation. One of the
very first questions put by the hi tending purchaser is — **\Vhat is such
a vehicle going to cost to maintain in service?*' — and a karge amount
of engineering talent is now employed in the commercial field in the
attempt to fonnulate an answer to this (juestion in each individual
case in which it is asked. In fact, the analysis of merchandise trans-
portation requirements and the cost of the service as compared with
old methods is rapidly developing into an engineering study of no
mean proportions.

It will be evident that under the circumstances, definite figures
are wanted by the purchaser, and they naturally can only be based
on actual experience. The merchant who contemplates making a
substantial investment in commercial vehicles wants to see something
more than a mere calculation of what their services will cost — ^not


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for a month or two months, but, as closely as can be judged, the
amount they will cost to run and maintain in repair during the first
year and each succeeding year of the useful life of the vehicle.

There are naturally many factors to be taken into consideration
in any complete cost-accounting system that is worthy of the name,
whether thi^ be for a single delivery wagon, or truck, or a whole de-
livery system, such as is employed by the large retail drygoods estab-
lishments. Lack of consideration of these numerous factors has
led many commercial vehicle manufacturers into stating half-truths
regarding the economic performances of their vehicles in the earlier
days, though it is not certair\ by any means that the practice
has entirely disappeared even now. The revelation of the whole
truth naturally proved a disappointment to the pioneer motor-vehicle
users, however, and the result was a feeling of distrust. It could
not have been worse had the manufacturer actually made misstate-
ments, for the user, regarded them as such in the light of his experi-
ence. To cite instances of what is meant by these half-truthful
statements, there may be mentioned the cases of cost summaries
which some makers print in their catalogues. Sometimes these
extend over a period of three months and in others, six months,
and the service records thus established are expected to be regarded
as a criterion of what the vehicle is capable of year in and year out.
In some cases, nothing for tire replacement is included, owing to
the short time the vehicle has been in use, not to mention such other
items as depreciation, interest, insurance, and other overhead charges.
Seldom, indeed, is the useful ton mileage of the car over the period
in question given, and quite a number of manufacturers, when ap-
proached for information on this vitally important subject, are not
loth to confess that they are unable to give it and that they have never
attempted to keep a record of the kind.

Some of the factors of importance are speed, reliability, wide radius
of travel, and even stylishness — ^which is considered an asset of the
motor delivery wagon — but, after all, cost must be practically the sole
governing factor by which the conmiercial motor vehicle is to be judged.
At the outset, it was really the uncertainty — that lack of reliability
which made the successful completion of a day's trip an entirely
unknown factor — that first militated against the commercial vehicle;
but since improvement in design, materials, and construction has


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eliminated that, the item of cost of operation is really paramount.
It manifestly lies more within the province of an article on cost ac-
counting for cpmmercial vehicle service, than of one which deals almost
entirely with the engineering side of the subject. Consequently,
the aim has been more to demonstrate what the commercial vehicle
is capable of — ^particularly as compared with fonner methods by
horse haulage, figures on the cost of operation being cited more to
show the superiority of the power wagon from an economic stand-
point as well — rather than to attempt to set forth exacdy what has
been or can be done in operating one or more vehicles.

Qasoline. Leaving aside the matters of interest, depreciation,
insurance, and repairs, it will be apparent that in the commercial
vehicle, fuel, lubricant, and tires are of far more importance than
in a pleasure car. One of the small 500-pound delivery wagons will
usually travel from 25 miles to 30 miles on a gallon of gasoline,
averaging better than 20 miles; a 10-ton truck will average less than
three miles to the gallon of fuel. Between these two extremes, there
is a wide range, a 1,500-pound delivery wagon running from 12 miles
to 20 miles to the gallon, with an average of about 15 miles, while a
3,000-pound machine (the figures refer to load capacity and not to
chassis weight) will not do better than from 8 miles to 15 miles per
gallon, with an average around 10 miles. A 3-ton truck will range from
4 miles to 10 miles, the difference in every case naturally depending
not only upon whether the vehicle is loaded or not, but also upon
differences in the road surface and grades of its routes. The 5-ton
wagon can travel from 3 miles to 5 miles on a gallon of fuel, its average
being about 4^ miles as compared with 6 miles for the 3-ton size.
A 14-ton road train may require as much as two gallons of fuel for
every mile covered, but will doubtless not be found to gready exceed
a gallon to the mile, except where the going is particularly bad.

Lubricating Oil. The consumption of lubricating oil ranges
between even wider limits than that of fuel, as will be apparent from
the fact that in a commercial vehicle trial in which a large number of
representative foreign vehicles competed, the ratio between the most
economical and the most wasteful was fully five to one. In other
words, some cars consumed five times as much lubricating oil per
mile as others in the same class. But then certain of the European
cars have proved to be highly economical in the use of lubricant and


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it is doubtful if there would be as wide a range between the same
number of American commercial cars, as few of them have approached
the degree of economy achieved in this respect by the French designer.
Experience has shown that the minimum consumption of oil, which
should be of the very best quality for the purpose, is about one gal-
lon for every 14 to 15 gallons of fuel used by the vehicle, while the
maximum is, approximately, one gallon for every six gallons of gaso-
line. Where much hill-climbing is the rule more oil would necessarily
be used, owing to the motor running for longer periods on the lower
gears and under correspondingly heavier loads. These figures are
based upon ordinarily competent management of the machine, and
while an expert driver, thoroughly conversant with his machine,
and supplemented by painstaking garage attendance, might do
somewhat better, incompetence in either of these departments can
swell these figures so tremendously that there is no means of estimating
to what proportions they may attain.

Tires. Next to fuel and oil come tires, and in figuring on this
subject an engineer who has had five years' experience in the com-
mercial field in a consulting capacity, gives the following: For a
500-pound wagon, f-cent per mile minimum, 2 J cents maximum,
average 1^ cents; 1,500-pound class, or regular delivery wagon type,
1, minimum, 3 J, maximum, and 2^ cents average per mile; 3,000-pound
class, H, 5, and 3^ cents per mile; 3-ton class, 2, 7, and 4| cents per
mile; 5-ton class, 3, 10, and 6 cents per mile. Against these figures,
may be placed those which the builders of the Manhattan cars give
as the result of five years' experience in the running of a large num-
ber of their own vehicles. Manhattan 2-ton truck, 2 cents per mile,
the figure in each case being the average; 3-ton truck, 2^ cents per
mile; 4-ton truck, 3 cents per mile; and the 5-ton truck, 4 cents per
mile, this last falling between the minimum and the average for this
class in the foregoing figures. Unfortunately no data is available
at the moment on tire costs on the electric vehicles, though it may be
stated definitely that owing to the lower average speeds and the
greater ease with which the load is started by the electric motor, this
type of vehicle shows much greater economy in tires than the gasoline
car, though exactly how much is a question that could only be an-
swered by a direct comparison of the figures.

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Total Cost of Operation. The cost of operating various sizes
of trucks is given in a different light by the makers of the Hewitt cars.
The figures are based on five years' constant operation, the vehicle
averaging 300 days in service — a task which should not be diflBcult
of accomplishment. On this basis, and figuring an average run of
50 miles per day, the tire figures for a Hewitt 2-ton truck are given
as $L34 per working day, or $.0268 per mile, which will be found to
practically agree with the averages already cited. On the same
basis, the tire cost of the 3-ton truck, averaging 45 miles per day,
300 days in the year, for five years, is $.037, or slightly more than 3^
cents per mile, as compared with the average of 4f cents given in
the first instance. This and other similar discrepancies between
the two may well be accounted for by the long period of operation
upon which the Hewitt averages are based, this naturally being more
conducive to a favorable showing. Under similar conditions and
averaging 40 miles a day, tire costs for a 5-ton truck are $.0583 per
mile — ^practically the same as the 6-cent average for the same type
in the first table. The cost of tire mileage naturally reaches its
maximum on the 10-ton size, the Hewitt figures for their vehicles
of this class being $.111 per mile, or between 11 and 12 cents.

From a basis of a five-year period of operation, it will be of
interest to compare daily total costs of operation in a few instances.
The following figures are given by the makers of the Manhattan
trucks and are baSed on an average run of 50 miles per day. For a
Manhattan 2-ton truck, the total daily operating cost — exclusive
of depreciation, insurance, and similar items as already mentioned —
is $5.88; composed of $1.50 for gasoline, five miles to the gallon at
15 cents a gallon; cylinder oil, one gallon, 38 cents; repairs and re-
newals 50 cents; tire changes, 2 cents per mile, or $1 ; and the driver's
wages, $2.50. Similarly figured, the 3-ton truck will run 50 miles
a day for $6.78, the 4-ton, $7.50, and the 5-ton, $8.00. According
to the makers of the Manhattan trucks, these figures are based upon
several years' experience in the handling of a large number of machines,
and to show how closely they agree with what other makers have
found under similar circumstances, they may well be compared with
those of the Hewitt machines in the same sizes.

Taking the Hewitt figures on a daily basis, that of the 2-ton
truck, based on exactly the same items, is $5.72 as compared with


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$5.88, though labor in the case of the Hewitt is included at $3 per
day, gasoline (15 cents per gallon) at only 90 cents, and lubricating
oil (30 cents per gallon) at only 15 cents, while tire charges are more,
or $1.34. In fact, there is hardly an item in which there is not a
noticeable discrepancy, yet the totals are so close together as to be
almost identical. In the 3-ton size, the charges are $6.22 per day
of 45 miles travel, compared with $6.78 per day of 50 miles travel
for the Manhattan, so that the totals are really equally close in this
case as well. For the 5-ton, the cost is $8.30 for the Hewitt's run
of 40 miles as compared with $8.00 for the Manhattan on the basis of
50 miles per day. That figures such as the above may be misleading
to an intending purchaser will be evident from the further detailed
costs cited by the makers of the Hewitt cars. These include every
possible factor of expense, including depreciation, interest on the
investment at 5 per cent, labor, tires, yearly overhauling, current
repairs, gasoline, oil, total cost of insurance, and cost of storage and
garage attendance.

They go to show that instead of involving a daily total expense
of but $5.72, this should be $9.60 in the case of the 2-ton truck;
$10.38 instead of $6.22 for the 3-ton size; and $12.67, instead of $8.30
for the 5-ton truck.

Mention has been made under Gasoline-Driven Trucks of the
fact that the 10-ton size is about the maximum which it has been
found commercially practicable to build as a single unit, the motor
road train being employed where it is desirable to transport larger
loads than this at one time. The Hewitt 10-ton truck is the only
representative of this class and some figures of its service performance
will be of interest. They refer to the truck. Fig. 75, and are based
on what it did during the last four months of 1909. The daily run
varied from 34 miles to 37 miles, with an average of 35.4. During
13 days in October, one of these huge trucks delivered 1092.39 tons
of coal, the round trip varying from 5.5 miles to 15 miles. The aver-
age tonnage per day was 84.03, or 8.3 loads per day, which were
made on an average gasoline consumption of a little less than 12
gallons, or 2.97 miles per gallon. The maximum cost of operation
per day was $16, including all charges, which gave an average cost
of $.19 per ton of coal for delivery. The weight of the empty car is
13,000 pounds, while the average weight of the load was 20,250


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pounds, giving a total of 33,250 pounds and making the average
rolling load, full and empty, 23,125 pounds. This gives a ton-mile-
age of 34.43 per gallon of gasoline, which is an excellent showing.

^Tiile no serious attempt has been made to analyze the cost of
operation of the conmiercial vehicle on a general scale, the figures
cited are all given as the result of several years' experience on the part
of those who are in a position to be cited as authorities in the matter,
so that the totab may be taken as a criterion. In other words, the
student who finds himself called upon to analyze the cost of a motor
delivery system and put his finger on the item that is making havoc
with calculations made in advance, may take it for granted that the
facts are fully representative of what may be accomplished by well-
built cars of the heavier types in the hands of competent men — a term
which is not intended to include either a factory expert or a novice.


Qasoline. So long as gasoline represents not alone the most
efficient fuel for use in motors of the present type, but likewise the
most convenient, it will doubtless continue to be generally employed
for pleasure-car use, regardless of its increasing cost. This effect-
ively answers the question as to why kerosene is not used for pleasure-
car propulsion. It is quite true that kerosene is cheaper and its value
as a fuel for the internal-combustion motor is slightly greater than
that of gasoline, but to realize its greater value it requires a motor
designed to give a heavier initial compression. Furthermore, it is
not as convenient as gasoline, for preheating is required to start the
motor from cold, because of the higher specific gravity of *kerosene,
which makes it less volatile, causing it to leave unsightly grease
stains on anything with which it comes in contact.

Similar conditions naturally do not obtain in the commercial
field, where the demand is for the most efficient and economical fuel.
In view of the enormous increase in the demand for gasoline,
coupled with the fact that the crude petroleum supply shows a con-
stantly decreasing proportion of the more volatile products — the
new wells of the Southwest are said to yield an oil producing not
more than five per cent of gasoline in the process of fractional distilla-

♦Note — Gasoline ranges from .62 to .67 sp.g. or 95 to 80 degrees Baum6,
while kerosene is approximately .80 to .82 sp.g. or 46 degrees Baum^«


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tion — it is evident that it is only a question of a comparatively few
years when gasoline will have reached a point where its use for com-
mercial service will not be economically practical. By improving
the methods of utilizing the fuel in the internal-combustion motor
it will become possible to use petroleum of lower and lower grades,
the Diesel motor now running directly on crude petroleum with an
efficiency far in advance of the most economical steam plants as well
as of most other forms of internal-combustion engine. But to ac-
complish this an extremely high compression is necessary — ^500
pounds to the square inch — and the weight involved in a construc-
tion required to stand such a pressure naturally makes the use of this
type of motor out of the question on a vehicle. Instead of being
employed in a carbureter in the manner usually followed on the auto-
mobile, air alone is compressed to this high pressure and the fuel is
then injected in the form of a spray directly into the combustion
chamber, at or slightly before the beginning of the power stroke.
The heat generated by the extremely high compression automatically
ignites the charge. While it does not appear probable that the
employment of pressures suflBciently high to accomplish this will
become possible on the commercial vehicle in the near future, the
method of injecting the fuel directly into the cylinder, instead of first
carbureting air as is now done, will doubtless have an important
bearing on the solution of the fuel problem.

Alcohol. Though volumes have been written during the past
few years, on the subject of alcohol as the coming fuel, it is the pre-
vailing impression that despite favorable legislation which has made
the employment of tax-free denatured alcohol possible, production
has not reached a point where its employment on a general scale is
commercially practical and that few attempts have been made to use
it in actual ser\ ice. The fact that gasoline can still be produced at a
price which makes it impossible for alcohol to compete with it, has
tended to delay the distillation of the latter on a large scale for fuel
purposes, besides retarding the manufacture of engines specially
adapted to bum it. When employed in an engine designed to run
on gasoline, alcohol is neither commercially nor practically efficient,
owing to its greater cost and the greater consumption per horse-power,
as well as the lower output of the same size motor, due to the lower
compression. But that it can be made so under proper conditions


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of operation is shown by the Hewitt trucks, described on Page 115.

The manufacturers of these heavy trucks offer their 5-ton and
10~ton types, equipped with a motor designed to run on alcohol
without any extra charge to the purchaser. In these motors, the
same quantity of alcohol develops a greater percentage of power than
gasoline does in a motor designed for the latter fuel. WTiile the
burning of an alcohol-and-air mi;cture is attended by the generation
of temperatures almost as high as the gasoUne-air mixture creates,
nevertheless, because of a peculiar phenomenon which has not been
satisfactorily explained, a greater proportion of the heat is absorbed
and there is considerably less tendency on the part of the motor to
overheat when running under a heavy load. In other words, less of
the heat that cannot be taken advantage of in the generation of power
has to be absorbed by the water jackets and dissipated by the radi-
ator. This is thought to be due to the fact that alcohol is never
anhydrous. It is readily miscible with water, which is a tremendous
advantage from the point of view of fire risk, and always carries five
to ten per cent of water in solution. Steam is instantaneously gen-
erated by the heat of the explosion from this water in the mixture,
and as it is far cooler at the moment of generation than the walls
of the combustion chamber, it tends to absorb the heat that would
otherwise have to be taken care of by the water jackets.

The makers of the Hewitt trucks state that their vehicles when
equipped with the special alcohol motor and run on that fuel, will
show an increase in mileage of fully 20 per cent over that possible
with the gasoline motor per gallon of fuel. At the present prevailing
prices for denatured alcohol, the cost of running a truck with it is
estimated to be approximately $1.25 more per day than with gasoline.
Furthermore there is, at present, no stability to the alcohol market
and prices for this commodity might unexpectedly rise to a pro-
hibitive figure. This has naturally deterred purchasers from invest-
ing in trucks equipped with alcohol motors, as the latter cannot be
run on gasolme owing to the higher initial compression employed,
which would cause pre-ignition.

Two years ago, the Department of Agriculture undertook an
exhaustive investigation of the subject, and as the result of experi-
ments made here and abroad, came to the following conclusions :

Alcohol contains O.G of the heating value of gasoline, by weight,


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and in the department's experiments a small, single-cylinder engine
— designed to run on gasoline — ^required L8 time^ as much alcohol
as gasoline per horse-power hour. This corresponds very closely
to the relative heating value of the fuels, indicating practically the
same thermal efficiency with the two when vaporization is complete.

By proper manipulation, any engine on the American market
today, designed to run on gasoline or kerosene, can be operated on
alcohol without any structural change whatever. In some cases,
however, carbureters designed for gasoline cannot properly vaporize
all the alcohol supplied, and in such cases the excess of alcohol con-
sumed over gasoline, is greater. But the absolute excess of alcohol
consumed over gasoline will be reduced by such changes in the design
of the engine as tend to increase its thermal efficiency.

By altering the design of the carbureter and increasing the
initial compression materially, any engine built to run on gasoline
will show an increased thermal eflBciency and will then consume less
alcohol per horse-power hour in proportion to this increase. An
engine designed for gasoline or kerosene will, without any material
alterations being necessary to adapt it to alcohol, show slightly more
power (approximately 10 per cent) with alcohol than with the fuels
for which it was designed, but this increase is at the expense of a
greater consumption of fuel. By making alterations designed to

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Online LibraryMedical Society of the State of North Carolina. AnCyclopedia of automobile engineering; a general reference work on the construction, operation, and care of gasoline, steam, and electric automobiles, instruction in driving, commercial vehicles, motorcycles, motor boats aerial vehicles, self-propelled railway cars, etc → online text (page 21 of 27)