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A single-cylinder Caterpillar diesel test engine was automated to run under close control without attention. Four types of data were logged on a single, 6-color, 12-point strip chart recorder using only 2 ft/day of specially ruled chart paper. The 16 data points recorded included 8 linear items (0-100 scale) such as pressures, fuel flow rate, speed, torque, and oil level; 5 iron-constantan (0-300 F) temperatures, and a chromel-alumel exhaust temperature (875-1300 F); also included were two 4-figure digital values for blowby rate and for fuel rate via an automated balance, each recorded in a unique fashion without a printer. Any conditions outside set limits actuated an alarm. Special equipment protected the engine against sudden, test-running (hot) shutdown if power, air, or fuel supply failed, or if control of critical variables failed.

TESTS conducted on a full-scale aircraft engine show that satisfactory engine operation can be obtained at warmed-up conditions with low-volatility fuels of the safety type. The engine used in the tests was modified for direct cylinder fuel injection, as fuels of this type are not sufficently volatile to be satisfactorily vaporized by means of a carburetor induction system. Knock-limited performance, specific fuel consumption, and oil dilution characteristics were studied in these tests.

PRESENT-DAY cars are not capitalizing on the continued efforts of the petroleum industry to provide better fuels, the authors believe. The wide differences found in the octane-number requirements of individual cylinders, plus the failure to obtain uniform mixture distribution from cylinder to cylinder without resorting to fuels of aviation-grade volatility have led them to reach this conclusion, they explain. The probability that significant reduction in the average antiknock requirements of cars might be effected without making any major changes in the engine is indicated by a survey of the technical literature, they point out. The extensive studies of ignition-system characteristics and gasoline-mixture distribution as affecting detonation reported in their paper bring out the following pertinent points: 1. Variations actually occurring in the spark advance from cylinder to cylinder may vary the octane-number requirement of individual cylinders by about 10 points. 2.