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THE GASOLINE AUTOMOBILE
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The present day motor car.
(Frontispiece)
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ENGINEERING EDUCATION SERIES
THE GASOLINE AUTOMOBILE
PREPARED IN THE
EXTENSION DIVISION OF THE UNIVERSITY OF WISCONSIN
BY
GEORGE W. HOBBS, B. S.
FOBMKBLT INSTRUCTOR IN MECHANICAL ENGINEERING
IN THE UNIVERSITY EXTENSION DIVISION
THE UNIVERSITY OF WISCONSIN
AND
BEN G. ELLIOTT, M. E.
FORMERLY ASSOCIATE PROFESSOR OF MECHANICAL ENGINEERING THE UNIVERSITY OF NEBRASKA
SECOND EDITION
COMPLETELY REVISED AND REWRITTEN
BY
BEN G. ELLIOTT, M. E.
PROFBSSOR OF MECHANICAL ENGINEERING THE UNIVERSITY OF WISCONSIN
AND
EARL L. CONSOLIVER, M. E.
ASSISTANT PROFBSSOR OF MECHANICAL ENGINEERING THE UNIVERSITY OF WISCONSIN
MCGRAW-HILL BOOK COMPANY, Inc.
239 WEST 39TH STREET. NEW YORK
LONDON: HILL PUBLISHING CO., Im>. a & 8 BOUVERIE ST., E. C.
1919
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Copyright, 1915, 1919, by the McGraw-Hill Book Company, Inc.
First Edition Fourteen Impressions
Second Edition First Impression, August, 1919
Total Issue, 38,500
TUX HAI'LK l'XKHH VOMK 1» X
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228211 fist*1?*/
OCT U 919
PREFACE TO SECOND EDITION
The developments in automobile practice since the first edition of The Gasoline Automobile have necessitated some changes and revisions in this edition. The entire book has been completely rewritten and en- larged. Much new illustrative material has been added. The number of chapters has been increased from ten to sixteen. Complete chapters are now given on "Chassis and Running Gear," "Clutches and Trans- missions," "Rear Axles and Differentials," while entirely new chapters on "Principles of Electricity and Magnetism," " The Automobile Storage Battery," and "Wheels, Rims and Tires," have been added.
No attempt has been made to cover all makes and models of cars and apparatus, but the purpose of offering instruction on the fundamental principles of automobile design, construction, and operation has been adhered to as far as possible.
Mr. Earl L. Consoliver, Assistant Professor of Mechanical Engineer- ing, has acted as co-author, taking the place of Mr. George W. Hobbs.
Ben. G. Elliott. The University op Wisconsin, Madison, Wisconsin, July, 1919.
Vll
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PREFACE TO FIRST EDITION
The purpose of this book is admirably expressed in the following quotation taken from the Buick instruction book: "To derive the greatest amount of satisfaction and pleasure from the use of his car the driver should have a complete understanding of the mechanical principles under- lying its operation. Merely knowing which pedal to press or which lever to pull is not enough. The really competent driver should understand what happens in the various parts of the car's mechanism when he presses the pedal or pulls the lever. He should know the cause as well as the result."
When we consider the complexity of modern automobiles from a mechanical standpoint, with the duties that are required of them, to- gether with the fact that the great majority of them are operated by men with little or no experience in the handling of machinery, the automobile stands as one of the most remarkable machines that the ingenuity of man has ever produced. The operating expense of the automobile has already assumed a large place in the budget of the American people. Although it is so built that the owner may secure good service from his automobile with very little knowledge of its construction, still it is evident that an intimate acquaintance with its details should enable him to secure better service at less expense and at the same time to prolong the useful life of the car.
It is with the hope of increasing the pleasure of automobile owner- ship and reducing the trouble and expense of operation that this book is offered. It is planned primarily for use in the University Extension work in Wisconsin, for the instruction of those who drive, repair, sell, or otherwise have to do with motor cars. It is largely the outgrowth of a series of lectures on the subject which were given in twenty-three cities of Wisconsin during the past winter.
The thanks of the authors are especially due to Mr. M. E. Faber of
the C. A. Shaler Co. for assistance in preparing the section dealing with
tire troubles, to Prof. Earle B. Norris for much of the chapter on Engines
and for editing the manuscript and reading the proof, and to the many
manufacturers who have liberally assisted in the preparation of the work
by supplying their cuts and other material.
G. W. H. Madison, Wis., Sept. 15, 1915.
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CONTENTS
CHAPTER I The Automobile
Art. Page
1. The steam propelled car 1
2. The electric car 1
3. The gasoline car 4
4. The gasoline-electric car 4
5. Types of cars 5
6. Passenger car bodies . : 5
7. Automobile bodies 8
8. Commercial cars 9
9. General principles of automobile construction 12
10. Control systems 16
CHAPTER II The Automobile Engine
11. The gasoline engine 17
12. Cycles 17
13. The four-stroke cycle 18
14. The two-stroke cycle 20
15. The order of events in four-stroke engines 20
16. The mechanism of four-stroke engines 21
17. Pistons and piston rings 22
18. Connecting rods 24
19. The crankshaft 25
20. The flywheel 25
21. Valves 25
22. Valve operating mechanism 27
23. Valve opening and closing 29
24. Half-time gears. 29
25. The Knight engine. 30
26. The fuel charge 31
27. Ignition 31
28. The muffler 33
29. Cylinder cooling 33
30. Piston displacement 34
31. Clearance and compression 34
32. Horsepower of engines 34
33. Derivation of the S. A. E. horsepower formula 35
xi
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xii CONTENTS
CHAPTER III
Automobile Power Plants Art. Paob
34. Multi-cylinder engines 37
35. Modern automobile power plants 38
36. Power plant support 39
37. Four-cylinder power plants 39
38. Ford power plant 39
39. White four-cylinder engine 40
40. Duesenberg engine 43
41. Guy rotary valve engine 43
42. Six-cylinder power plants 44
43. Marmon power plant 44
44. Franklin air cooled engine 47
45. The Hall-Scott engine 47
46. Chandler six power plant 48
47. Constructional features of four- and six-cylinder engines 48
48. Six-cylinder crankshafts 50
49. Camshafts 53
50. Eight- and twelve-cylinder power plants 53
51. Cadillac eight-cylinder engine 54
52. The Oldsmobile eight-cylinder engine 56
53. King eight-cylinder engine 57
54. Knight eight-cylinder engine 58
55. Firing order of eight-cylinder engines 58
56. Determining firing order of eight-cylinder engine 60
57. Packard twelve-cylinder engine 60
58. National twelve-cylinder engine 60
59. Pathfinder twelve-cylinder engine 62
60. Firing order of twelve-cylinder engines 63
CHAPTER IV
FUEL8 AND CaRBURETTINO SYSTEMS
61. Hydrocarbon oils 65
62. Refining of petroleum 65
63. Gasoline 67
64. Principles of vaporization 68
65. Testing gasoline 68
66. Kerosene and alcohol 70
67. Heating value of fuelo 70
68. Gasoline and air mixtures 70
69. Principles of carburetor construction 71
70. Auxiliary air valves 72
71. Air valve dashpots 74
72. Float chambers and floats 74
73. Metering pins 74
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Abt. pAai5
74. Operating conditions of the carburetor 74
75. Schebler model L carburetor 75
76. Schebler model R carburetor 77
77. Marvel carburetor 79
78. Bayfield model G carburetor 81
79. The Holley model H carburetor 84
80. Holley model G carburetor 86
81. Kingston model L carburetor 87
82. The Tillotson carburetor 88
83. Zenith model L carburetor 90
84. Stewart model 25 carburetor 91
85. Stromberg plain tube carburetor 92
86. Stromberg model H carburetor 96
87. The Hudson carburetor 98
88. Cadillac carburetor 98
89. Packard carburetor 98
90. General suggestions on carburetor adjustment and operation 99
91. Intake manifolds 100
92. Carburetor control methods 101
93. The gasoline feed system 101
94. Care of gasoline 105
CHAPTER V Engine Lubricating and Cooling
95. Lubrication and friction 107
96. Lubricants and lubrication 107
97. Test of lubricating oils 108
98. Gas engine cylinder oil 109
99. Systems of engine lubrication 110
100. Full splash system of lubrication Ill
101. Splash system with circulating pump 112
102. Pressure feed and splash lubrication 114
103. Pressure feed system 114
104. Pull pressure or forced feed system 116
105. Oil pumps 116
106. Engine lubrication in general 118
107. Cylinder cooling 118
108. Thermosyphon cooling system 120
109. Pump or forced system of water circulation 121
110. Packard cooling system 122
111. Cadillac cooling system 123
112. Air cooling 125
113. Radiators 126
114. Temperature indicators 127
115. Cooling solutions for winter use 127
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xiv CONTENTS
CHAPTER VI
Principles op Electricity and Magnetism
Art. Pack
116. Electricity • 131
117. Conductors and non-conductors 131
118. Hydraulic analogy of electric current 132
119. Resistance 132
120. Relation between current, voltage, and resistance 133
121. Electrical power 134
122. Effects of electric current 134
123. The dry cell 135
124. The storage battery 136
125. Wiring of ignition batteries 137
125. Magnetism 139
127. Natural and artificial magnets 139
128. Magnetic and non-magnetic metals 139
129. The poles of a magnet 140
130. The magnetic field 141
131. Electromagnetism 142
132. The electromagnet 143
133. To determine the polarity of an electromagnet 144
134. Electromagnetic induction 144
135. The right-hand rule 146
CHAPTER VII Battery Ignition Systems
136. Automobile ignition 147
137. The low^tension coil for make-and-break ignition 147
138. The induction coil 148
139. The safety gap 151
140. The condenser 151
141. The vibrating induction coil 153
142. The three terminal coil 154
143. The vibrating type ignition system 154
144. Timers 155
145. Spark plugs 156
146. Spark plug testing 158
147. Typical battery ignition system 159
148. The distributor 160
149. The ignition resistance unit 160
150. Spark advance and retard 161
151. Automatic spark advance 162
152. The Atwater-Kent ignition system — open circuit type 163
153. The Atwater-Kent ignition system, Type CC 167
154. The Connecticut battery ignition system 169
155. The Remy ignition system 174
156. The Remy-Liberty ignition breaker for U. S. Military Truck 178
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CONTENTS xv
Art. Page
157. The North East ignition system • 178
158. The Delco ignition system 181
159. Delco ignition breakers for eight- and twelve-cylinder engines 184
160. Timing battery ignition with the engine 185
161. Care of battery ignition system 186
CHAPTER VIII Magnetos and Magneto Ignition
162. Magneto classification 187
163. Magneto magnets 187
164. lines of force 188
165. Types of magnets • 188
166. Mechanical generation of current 189
167. Low- and high-tension magnetos 190
168. Armature and inductor type magnetos 191
169. Current wave from a shuttle- wound armature 191
170. Low-tension magneto ignition system with interrupted primary current . . 193
171. Low-tension magneto ignition system with interrupted shunt current . . . 194
172. Dual ignition systems 196
173. Splitdorf low-tension dual ignition system with type T magneto 197
174. Remy inductor type magneto 198
175. The Ford ignition system 202
176. The high-tension magneto 205
177. The Bosch high-tension magneto 205
178. The Bosch high-tension dual system 215
179. The Bosch high-tension magneto, type NU4 217
180. The Eisemann high-tension magneto, type G4 220
181. The Eisemann high-tension dual magneto, type GR4 225
182. Timing of the Eisemann magneto to the engine for variable spark .... 227
183. The Dixie magneto 229
184. General instruction for high-tension magneto care and maintenance . . . 233
CHAPTER IX
The Automobile Storage Battery
185. Function of the battery 237
186. Construction 237
187. The plates 238
188. Positive and negative groups 238
189. Elements 238
190. Separators 239
191. The electrolyte 242
192. Jars and covers 242
193. Cell arrangement 243
194. Battery box 243
195. Markings of the battery 244
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xvi CONTENTS
Art. Paob
196. Voltage of the battery 244
197. Battery capacity 244
198. Principle of operation 245
199. Effect of overcharging 245
200. Effect of undercharging 245
201. Heat formed on charge and discharge 246
202. Evaporation of water 246
203. Necessity of adding pure water 247
204. Cause of specific gravity change . » 247
205. The hydrometer 247
206. Hydrometer readings 248
207. Variation in cell readings 248
208. Variation in hydrometer readings caused by temperature 249
209. Freezing temperature of the battery 250
210. Results of freezing 251
211. Battery charging 252
212. Detailed instruction for charging batteries 254
213. Battery testing with the voltmeter 255
214. Sulphation 256
215. Effect of overfilling 257
216. Corroded terminals 258
217. Disintegrated and buckled plates 258
218. Sediment 260
219. Conditions causing the battery to run down 260
CHAPTER X Starting and Lighting Systems
220. Automobile starters 263
221. Mechanical starters 263
222. Air starters 263
223. Acetylene starters 263
224. Electric starters 264
225. Hydraulic analogy of an electric starting and lighting system 266
226. Generator drives 268
227. Starting motor drives 270
228. The bendix drive 273
229. Motor-generator drives 275
230. Construction of the dynamo 277
231. The simple alternating-current generator 280
232. The simple direct-current generator 281
233. The simple direct-current motor 282
234. The shunt-wound generator 284
235. Conditions which prevent a generator from building up 286
236. Types of field winding 287
237. The reverse current cut-out 28t
238. Regulation of the generator 29(
239. Generator regulation through reverse series field winding 291
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Abt. Paqb
240. Current regulation of the generator through vibrating type relay 293
241. Voltage regulation of the generator through vibrating type relay .... 295
242. Combined current and voltage regulation of the generator through vibrating type relay 297
243. The Ward Leonard automatic controller 298
244. Third brush regulation 300
245. Characteristics of third brush regulation 304
246. The Remy generator with thermostatic control 304
247. The Remy starting and lighting system with relay regulation 307
248. The Bijur generator with constant voltage regulation 310
249. The Westinghouse starting and lighting system— voltage regulator type. . 311
250. The Westinghouse starting and lighting system — third brush type .... 315
251. The North East starting and lighting system on the Dodge car 318
252. The Delco single-unit starting, lighting, and ignition system on the Buick . 322
253. The Delco two-unit starting, lighting, and ignition system on the Olds- mobile Eight 327
254. Delco-Iiberty lighting system on U. S. standardised military truck — class B. 330
255. The " F. A. Liberty " Ford starting and lighting system 334
256. Automobile lamps and reflectors 338
257. Care of starting and lighting apparatus 340
CHAPTER XI The Automobile Chassis and Running Gear
258. General arrangement of chassis 343
259. Frames 343
260. Springs and spring suspension 345
261. Unsprung weight 355
262. The front axle 356
263. Steering system 357
264. Steering gear 358
265. Brakes 360
266. Transmission brake 363
267. Effectiveness of brakes 363
268. Antifriction bearings 364
CHAPTER XII Clutches and Transmissions
269. The automobile clutch 367
270. The cone clutch 367
271. The disc clutch 371
272. Operation of clutch ....................... 375
273. Change gear sets 375
274. Operation of the gear set ...................... 378
275. lubrication of the transmission ................... 379
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xviii CONTENTS
Art. Page
276. Gear shift levers 379
277. Location of transmission 380
278. The planetary transmission 380
279. Operation of planetary transmission 383
280. Universal joints and propeller shaft 386
281. Lubrication of universal joints 387
282. Flexible couplings 387
283. Propeller shaft 387
CHAPTER XIII Rear Axles and Differentials
284. Final drives 389
285. Bearings for final drive 391
286. Types of rear axles 391
287. Simple live rear axle 392
288. Semi-floating rear axles 392
289. Three-quarter floating axle 394
290. Full-floating rear axle 396
291. The differential 396
292. M. & S. differential or Powrlok 398
293. Lubrication of rear axle and differential 400
294. The torque arm 400
295. Strut rods 402
CHAPTER XIV
Wheels, Rims, and Tires
296. Wheels . . 403
297. Wooden wheels 404
298. Wire wheels 405
299. Other types of wheels 406
300. Rims . . 407
301. Removal of demountable rims 410
302. Types of tires 411
303. Construction of tires 412
304. Proper use and care of tires 415
305. Proper inflation 415
306. Tires of proper size 417
307. Care in application of tires to rims 418
308. Rim irregularities 418
309. Flat tires 418
310. Fabric bruises 419
311. Improper braking 419
312. Tight chains 420
313. Wear of tire by parts of car 421
314. Alignment of wheels 421
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Abt. Paoe
315. Ruts and car tracks 421
316. Neglected injuries 422
317. Oil on tires .422
318. light and heat 422
319. Fast driving 422
320. Poorly made repairs 423
321. Tire powder 423
322. Inserting inner tubes 424
323. Care of spare tubes 424
324. Leaky air valves 425
325. Tire fillers 425
326. Tire protectors ^ 425
327. Spare casings 425
328. Care of tires — car in storage 425
329. Repair of tires. .' 426
CHAPTER XV Automobile Troubles and Remedies
330. Classification of troubles 427
331. Power plant troubles 427
332. Mechanical troubles in engine 431
333. Carburetion troubles 437
334. Ignition troubles 438
335. Starting troubles 444
336. Lighting troubles 445
337. Lubricating and cooling troubles 448
338. Transmission troubles 450
339. Chassis troubles 450
CHAPTER XVI Operation and Care
340. Preparations for starting 453
341. Starting the engine with the electric starter 455
342. Cranking by hand 455
343. How to drive 456
344. Use of the brakes 457
345. Speeding 458
346. Speedometers 459
347. Care in driving 459
348. Driving in city traffic 460
349. Skidding 461
350. Knowing the car 463
351. The spring overhauling 463
352. Washing the car 465
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Art. Paqb
353. Care of the top 466
354. Cleaning the reflectors 466
355. Care of tires 466
356. Figuring speeds 468
357. Insurance 469
358. Interstate regulations 469
359. Canadian regulations 470
360. Touring helps. Route books 471
361. Cost records 471
Index 475
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THE GASOLINE AUTOMOBILE
CHAPTER I
THE AUTOMOBILE
Automobiles may be classified according to the type of power plant used, as steam, electric, gasoline, and gasoline-electric; or they may be divided into two classes according to use, as passenger cars and com- mercial cars.
1. The Steam Propelled Car. — The steam engine, when used on an automobile, has the advantage of being very flexible. All operations such as starting, stopping, reversing, and acquiring changes of speed can be done directly through the throttle on the steering wheel. By opening or closing the throttle, more steam or less steam is supplied to the engine, and the power is increased or decreased in proportion. When the car is climbing a hill, it is necessary only to give the engine more steam. This results in more power being delivered. The fact that the steam engine is able to start under load eliminates the clutch and also the transmission or change speed gears, the engine being connected directly to the rear axle. The arrangement of the parts on the Doble steam car is illustrated in Fig. 1.
The disadvantage of the steam propelled car is that it sometimes requires considerable time to raise the steam pressure before starting. This is especially true if the boiler has been allowed to cool off. If it is desired to keep the steam pressure up so that the car can be started without loss of time, a pilot light must be kept burning under the boiler at all times. The steam pressure carried is very high, and this means that constant care and attention must be given to the boiler and its accessories. The steam car requires that the boiler be filled with water for making steam every 150 to 250 miles. Kerosene is generally used for heating the boiler.
2. The Electric Car. — The advantages of the electric car are similar to those of the steam car. The electric motor is very flexible in operation and can be operated entirely by the control levers. By supplying more current or less current to the motor the power is increased or de- creased accordingly. The electric car is especially adapted to the use of women and children in cities. It is an easy riding car, clean, and runs quietly.
1
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THE GASOLINE AUTOMOBILE
tlOTOR dc FAN'"
THROTTLE VALVE— *k
HAND BRAKE
IGNiT/ON AND-- LIGHTING SWITCH
CRANK CASE
AND DIFFERENTIAL^
HOUSING
BRAKE COOLING FLANGES
^CONDENSER
STEAJ1 GENERATOR
-SERVICE BRAKE -WATER TANK
— THROTTLE CONTROL
CYLINDERS ■-■
FRONT END -ENGINE SUPPORT
.^ WATER PUMPS
ELECTRIC MOTOR GENERATOR
KEROSENE TANK
Fio. 1. — Chassis of Doble steam car.
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THE AUTOMOBILE
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4 THE GASOLINE AUTOMOBILE
The disadvantages are that it is not suitable for long drives, heavy roads, or hilly country. On one charge of the battery the average car will run from 100 to 150 miles, depending on the speed of the car and the condition of the roads. If the car is run at high speed, the battery will not drive the car as far as it will when running at a moderate rate. This car is also limited to localities where there are ample facilities for charging the storage batteries.
3. The Gasoline Car. — The gasoline engine is very economical as an automobile power plant. After being started, it has great flexibility. It is especially adapted for touring purposes and does not require any great attention from the operator. The average car carries enough fuel to run it 200 to 400 miles. It is then necessary to refill the gaso- line tank. Occasionally, a quart or two of water should be put into the . radiator. With proper care, the engine will run as long as the gasoline supply and the electrical system hold out.
The disadvantages of the gasoline engine as compared with those of
the steam engine or electric motor are, first, the gasoline engine is not
self -starting; and, second, it lacks overload capacity. On account of
these two factors some method of changing the speed ratio of the engine
to the rear wheels is necessary in order to acquire extra power for start-
ii ig the car, for climbing hills, for heavy roads, and also for reversing
tlK ^ car» as *^e ordinary four-stroke automobile engine is not reversible.
The Qosoline engine will not start under load. This necessitates the use
of a c lutch, so that the engine can be started and speeded up before any
load is thrown on. Apparently, there are a great many disadvantages
to the g vsoline engine but in reality they are very few, for with the proper
handling °f the spark and throttle control levers it is not necessary to
keep chan ^g gears continually. The gear shifting lever need not be
used excep f' f°r starting, stopping, hill climbing in congested districts,
and on bad . toads.
The ad va* stages of the gasoline engine for use on an automobile are so numerous tl ^ it is universally used for driving pleasure and com- mercial cars. 1 \ure 2 is a plan view of a modern gasoline driven
automobile.
4. The Gasolint Velectric Car. — The gasoline-electric or the dual- power car is driven h, Y a combination of a gasoline engine and an electric motor. This arrange. Xient, illustrated in Fig. 3, gives the advantages of both the gasoline car #nd the electric car. The electric motor is con- nected directly to the ^Vopeller shaft running to the rear axle. By means of a magnetic clui^h, the gasoline engine can be connected to the shaft of the motor. there are no change gears or transmission. The car is started by the e Vctric motor, and, after a certain speed is attained, the engine may be started by a magnetic clutch. Power for
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THE AUTOMOBILE 5
running may be obtained either from the electric motor and batteries, from the engine alone, or from both.
6. Types of Cars. — In general, there are two types of motor cars — passenger cars and commercial cars — the names indicating the use for which each type is intended. The parts of the passenger and commercial car are similar except that in the passenger car the construction is lighter than in the commercial car. In the passenger car everything is planned for comfort and speed, while the commercial car is built for heavy loads and is generally intended to be driven at lower speeds.
6, Passenger Car Bodies. — The principal types of bodies for passen- ger cars are the roadster, the touring car, the coupS, the sedan, the limou- sine, and the town car. These are shown in Fig. 4.
MAGNETIC CLUTCH,
PROPELLER. SHAFT
STORAGE BATTERIES
GASOUNE ENGINE
MOTOR GENERATOR
Fia. 3. — Chassis of dual power car.
The roadster body is open and usually has one seat for either two or three persons. Occasionally, both front and rear seats are provided, increasing the seating capacity to four. In this case, the front seat is divided by an aisle which furnishes the entrance from the front doors to the rear seat. The name doverleaf is sometimes given to this type of roadster body. The seating arrangement of the Chandler four-pas- senger roadster is seen in Fig. 5.
In the touring car body, which is also open, rear seats with separate rear doors are provided. The seating capacity is for five or even seven, in which case two additional folding seats, in front of the rear seat, are provided. In some cases only rear doors are provided, the entrance to the front seats being through the aisle. Figure 6 illustrates a seven- passenger touring car with the two auxiliary folding seats in front of the rear seat.
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THE GASOLINE AUTOMOBILE
The coupS is similar to the roadster excepting that it is enclosed and inside operated. It has seating capacity for two or three, and quite often a small seat which faces backward provides for another passenger. When a coup6 is provided with a detachable top or sides as in Fig. 7, it gives all the advantages of an open roadster. Such a coup6 is some- times called a convertible coup6 or cabriolet
The sedan is practically an enclosed touring body. It may be of the single or two door type. If of the single door type, the front seat
Roadster.
Touring car.
Coupe.
Sedan.
Limousine. Town car.
Fig. 4. — Types of passenger car bodies.
is divided by an aisle to furnish an entrance. In some types of sedan bodies, the sides can be removed during summer use, giving practically all the advantages of an open touring body. A double door sedan is illustrated in Fig. 8.
The limousine is a closed body, seating three to seven persons, with the driver's seat in front covered with a top. If the driver's seat is
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Fiq. 5. — Seating arrangement of Chandler four passenger roadster.
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open and not covered, the body is called a brougham or town car. If on either a limousine or town car, arrangements are provided for throwing open the housing of the rear seat, Fig. 9, the body is called a landauht.
Fia. 6. — Seven passenger touring car with auxiliary rear seats.
7. Automobile Bodies. — Automobile bodies are usually made of pressed steel, combining both strength and lightness, and built up on wooden frames, as indicated in Figs. 10 and 11. Some bodies are built
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of sheet aluminum which is considerably lighter than the other metals, but is more costly and is not so serviceable as the pressed steel.
8. Commercial Cars. — Commercial cars are built for light, medium, or heavy duty. They are usually classified as delivery cars and trucks.
Fig. 7. — Convertible coup6 body.
The delivery cars are lighter and are usually driven at higher speeds than the trucks, which are for heavier and slower service. Some typical commercial cars are illustrated in Fig. 12. Commercial cars are built
Fig. 8. — Double door sedan body.
on the same fundamental principles as passenger cars, but the construc- tion is heavier and more sturdy. In a great many cases, passenger cars
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Fiq. 9. — Limousine — Landaulet body.
Fio. 10. — Wooden frame for automobile body.
Fiq. 11. — Pressed metal automobile body.
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Ford light truck chassis.
Kissel medium truck.
Packard heavy truck. Fiq. 12. — Typical types of commercial cars.
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are converted for commercial use by putting on a body adapted for commercial purposes.
9. General Principles of Automobile Construction. — The two prin- cipal divisions of an automobile are the body and the chassis. The chassis includes all parts, with the exception of the body and its im- mediate attachments. The frame, springs, axles, wheels, steering gear, power plant, clutch, transmission system, and control apparatus go to make up the automobile chassis. These parts are fully illustrated in Figs. 2 and 13.
Frame. — The frame may be called the foundation of the automobile because it furnishes the support for the body, engine, transmission system, etc. It must be strong, light, and at the same time not too rigid. It is desirable to have the frame as long as possible as this in- creases the wheel base, giving an easier riding car. The wheel base is the distance measured between the centers of a front and rear wheel. Frames are usually made of steel although some wooden frames are used.
Springs. — As on any type of vehicle, springs must be provided to take the jars and bumps, due to rough roads, and to make an easy riding car. Springs of the laminated leaf type are attached to the frame, providing a flexible connection between the frame and the front and rear axles. In most cases four springs are used, but on some of the lighter cars only two springs, one front and one rear, are provided.
Front Axle. — The front axle which carries the weight of the front of the car is generally of the solid type and is attached directly to the front springs. Unlike the front axle on a wagon or carriage, the front axle on an automobile does not turn on a fifth wheel for the purpose of steering, but is fixed to the springs. Movable spindles, which carry the wheels, are provided on the axle ends for the purpose of steering. These spindles are tied together by a rod so that they move both wheels in the same direction when the car is being turned. The steering of the car is done by the steering wheel and its connection to the front wheels, as indicated in Fig. 14. The front wheels support the weight of the front of the car and serve for steering purposes but in most cases do not assist in driving the car.
Power Plant. — The power for driving an automobile is furnished by the engiqf which is supported on the front of the frame. In some cases a sub-frame, attached to the main frame, supports the engine, which is placed parallel to the sides of the frame. Most of the engine auxiliaries are placed either on or very near to the engine itself. The radiator is supported on the frame in front of the engine. The gasoline tank, in which the fuel is carried, is placed either at the extreme rear of the frame, or above and close to the engine, such as under the front seat.
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Clutch. — It is sometimes necessary that the engine be run when the car is not moving, so a device has been provided to disconnect the engine from the car driving mechanism. This device is called the clutch. If a clutch were not provided it would be necessary to stop the engine every time the car stopped. It would also be impossible to start or run the engine without having the car move. The power from the engine is delivered through the clutch to the change gears, or transmission, as it is usually called.
Change Gears or Transmission. — The transmission is a system of gears which makes it possible to change the speed ratio of the engine and the car. When the car is being started, or, when going up steep
STEERING WHEELS
'STEERING KNUCKLE ^SOL tO FRONT AXLE
Fiq. 14. — Method of steering an automobile.
hills, it is necessary that the engine run comparatively fast with respect to the car. After the car has gotten up speed, the engine can be run slower with respect to the car speed. The change gears also furnish the means for reversing the direction of the car. The change gears are usually placed at the front of the propeller shaft, but occasionally are found at the back of the propeller shaft, near the rear axle.