Abstract
To obtain true factual results from tests carried out on the test bed and on the road, instruments are necessary. The author describes his own experiences with various instruments and test methods, for example, the use of thermocouple sparking plugs for carrying out distribution tests, and the advantages of and characteristic results obtained from a smoke meter on a compression-ignition engine. After a brief comment on electronic instruments in general, he describes the balanced-pressure method of obtaining indicator diagrams at high speed, using a cathode-ray apparatus. Some typical results are given, and the methods by which the apparatus with a few additions can be used to measure torsional-vibration amplitudes of crankshafts (with practical examples), and by which a friction damper is adjusted to the correct condition, are shown.
The final section deals with road testing; in this the author advocates the use of a recording accelerometer for obtaining greater accuracy in brake and acceleration tests, and shows how such an instrument can also be used for measuring cornering forces, assessing the riding qualities, or recording gradients. Some results are given, and the design of such an instrument is dealt with.
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