Some Considerations of the Effect of Atmospheric Conditions on the Performance of Automotive Diesel Engines

A decompression chamber for testing automotive diesel engines at simulated altitudes up to 12,000 ft is described. Results obtained on seven naturally aspirated and one turbocharged diesel engine are discussed in relation to the day-to-day correction of engine performance and to site rating of engines. Comparisons are made between experimental results and existing correction methods, and modifications or replacements of the latter are suggested.

Results are assessed in terms of the correction method proposed in SAE standard J816. Attention is drawn to the different bases which may be used in correcting engine performance (for example, constant fuel delivery or constant exhaust smoke density) and the need to consider changes of exhaust smoke density or fuel consumption depending on the correction basis chosen.