Motor oils contribute to combustion-chamber deposits and therefore to octane-requirement increase (ORI) and surface ignition. An investigation of the separate components of motor oils in laboratory engines showed that base oils add the largest increment to ORI, viscosity-index improvers add less, and detergents and inhibitors add the least. Surface ignition is reduced by phosphorus, barium, calcium, and zinc ─ elements commonly found in motor-oil additives. Phosphorus is especially effective; all tested additives containing it were equally effective at the same concentration of phosphorus.The components chosen for a motor oil determine how much it will contribute to ORI and surface ignition. A good choice of base stock, viscosity-index improver, and detergent for an SAE 10W-30 oil gives an ORI 6 octane numbers lower than a poor choice. Similarly, choosing phosphorus-containing detergents and inhibitors reduces octanes needed to suppress surface ignition as much as l4 units. Good formulation of motor oils can do much to save costly octane numbers.
OCTANES FROM MOTOR OILS
Sae Technical Papers
Pre-1964 SAE Technical Papers ; 1906
1958-01-01
Conference paper
English
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