Relation Between Laboratory Knock Ratings and Customer Satisfaction on the Road
SourceThe antiknock performance of a gasoline depends on how the gasoline is used; the significant performance is that which can be recognized by customers in their automobiles in normal operation. Such performance can be accurately appraised only by rating gasolines in automobiles. Because such rating is not practical for refinery control and routine appraisals, road antiknock quality must be estimated from results of laboratory tests. Neither one nor a combination of ASTM Research and Motor ratings accurately predicts antiknock performance in automobiles; gasoline composition, lead-alkyl amount and type, sulfur content, and distribution of octane rating with volatility also affect it. Better knock-test methods with more realistic engine design, operating conditions, and instrumentation should be developed to provide simpler and more accurate predictions.