CHAPTER XII
LIQUID FUELS— Petrol 108 Benzol 108 Alcohol 109 Paraffin 109 Thermal Efficiency 110
APPENDIX
ENGINE TROUBLES 113
TIMING THE IGNITION 115
INDEX 117
LIST OF ILLUSTRATIONS
FIG. DESCRIPTION. PAGE
1. Diagram to explain the meaning of _Suction_ 1
2. Diagram to explain the meaning of _Compression_ 2
3. Otto Cycle. The Suction Stroke 3
4. Otto Cycle. The Compression Stroke 4
5. Otto Cycle. The Power Stroke 5
6. Otto Cycle. The Exhaust Stroke 6
7. General arrangement of a Modern Petrol Engine 9
8. Sectional Drawing of a =T=-headed Cylinder 12
9. Outside View of a Water-jacketed Cylinder 13
10. Stud 14
11. Bolt 14
12. Setscrew 14
13. Motor-cycle Engine with air-cooled Cylinder 14
14. Aeroplane Engine Cylinder 15
15. Cast-iron Piston 18
16. Method of fixing Gudgeon Pin 19
17. Three forms of Piston-head 19
18. Connecting Rod in the form of a Stamping 20
19. Connecting Rod turned from a solid Bar of Steel 21
20. Crankpin and Crankwebs 22
21. Four-throw Crankshaft 23
22. Motor-cycle Crankpin 24
23. Balanced Crank 25
24. Sketch showing the unbalanced portion of a Crank 25
25. Balanced Two-throw Crankshaft 26
26. Force acting on a Flywheel Rim 26
27. Built-up Steel Flywheel 27
28. Flywheel turned from a Steel Stamping 28
29. General arrangement of a Poppet Valve 30
30. Sectional Drawing of the Cylinder of a Sleeve-valve Engine 31
31. Sectional Drawing of the Cylinder of a Sleeve-valve Engine 32
32. Poppet Valve-head, showing Slot for Grinding-in purposes 34
33. Inlet and Exhaust Valve Cams 34
34. Eccentric Sheave and Rod for a Sleeve Valve 36
35. A Pair of Timing Wheels 37
36. A Crank Chamber, outside end view 39
37. A Crank Chamber, sectional view 39
38. General arrangement of the Carburetting Plant 43
39. Sectional Drawing of a Carburettor of the _Jet_ Type 44
40. Plain Form of the Choke Tube 47
41. Petrol Jet for _atomising_ the Petrol 48
42. Compensated Petrol Jet 48
43. Automatic Spring-controlled Extra-air Valve 49
44. Plan View of Automatic Extra-air Valve 49
45. Sectional Drawing of a Sparking Plug 51
46. A Sparking Plug 52
47. Outside View of a High-tension Magneto 52
48. View of High Tension Magneto showing Distributor and Contact Breaker 53
49. End View of High Tension Magneto 54
50. An Ignition Coil 56
51. An Ignition Coil Case 57
52. Low Tension Contact Breaker for Coil Ignition (Wipe Form) 58
53. Wiring Diagram for Four Cylinder Engine with Magneto Ignition (High Tension) 60
54. Wiring Diagram for Four Cylinder Engine with Trembler Coil Ignition 61
55. Improved System of Splash Lubrication 64
56. Sectional View of Connecting Rod end, showing Scoop and Oil Trough 65
57. Forced Lubrication System 66
58. Sectional View of Rotary Oil Pump 67
59. A Rotary Oil Pump 67
60. Thermo-syphon Water Cooling System 69
61. Forced Water Circulation by means of a Pump 70
62. Forms of Water Piping 74
63. Two-port Two-stroke Engine with Crankchamber Compression 81
64. Diagrammatic Sketch of a Duplex Two-stroke Air Scavenging Engine 87
65. General Arrangement of the “Kean” Two-stroke Engine 91
66. Twin-cylinder Two-stroke Engine with Crankchamber Compression 97
67. Petrol Engine Brake 100
68. Force-space or “Work” Diagram 103
69. Petrol Engine Indicator Diagram Four-stroke Cycle 105
70. Petrol Indicator Diagram for a Two-stroke Engine 106
71. Diagram of Valve-setting 116
PREFACE
This book deals with _principles_. There are many books which give a descriptive account of existing types of engines, but my object in writing this volume has been to assist the reader to obtain thoroughly sound notions of the _principles_ of design and construction which underlie all current practice. If a man understands, for example, the construction of the _elements_ of a carburettor and how they ought to perform their several functions, he should have no difficulty in understanding any special type of carburettor placed upon the market. In dealing with the subject of ignition I have purposely avoided any detailed explanation of the manner in which the spark discharge is produced, because I felt that it introduces new ideas and probably causes the reader to lose sight of the fact that the magneto is only, after all, an _accessory_, although of course a most important one. I hope that the accounts of my experiments with the _two-stroke_ will be of some service to inventors and others; the many extraordinary breakdowns, defects and adventures encountered during this period of my career have not been inserted because they would undoubtedly cause the reader to forget, for the time being, his fundamental _principles_.
My colleague, Mr. Oliver Mitchell, who lectures at the Polytechnic on “Motor Car Management and Inspection,” has read through the proofs for me and very kindly suggested several small additions to the text, which I have incorporated; he also suggested the insertion of the valve-setting diagram in the Appendix. My thanks are due to Mr. Mitchell for his services and also to my wife for her assistance in the preparation of the Index.
FRANCIS JOHN KEAN.
THE POLYTECHNIC SCHOOL OF ENGINEERING, REGENT STREET, LONDON, W.
_July, 1915._
THE PETROL ENGINE