DICTIONARY OF AUTOMOTIVE TERMS - "Oc"

OC

1. Acronym for Overhead camshaft.
2. Acronym for Oxidation catalyst
3. Acronym for Oxidation Catalytic Converter

OCC

1. Acronym for Output Circuit Check (Ford)
2. Acronym for output cycling check

Ocean liner blast horn

A horn which imitates the deep bellow of an ocean liner horn

OCIL

Acronym for Overdrive Cancel Indicator Lamp

OCS

1. Acronym for Overdrive Cancel Switch
2. Acronym for Outer Continental Shelf

OCT ADJ

Acronym for Octane Adjust Fuel Switch

Octagonal bolt

A bolt with an eight-sided head

Octagonal head bolt

A bolt with an eight-sided head

Octagon nut

A nut with eight sides

Octane

A flammable liquid hydrocarbon found in petroleum. Used as a standard to measure the anti-knock properties of motor fuel.

Also See
Iso-octane
Motor octane number
Research octane number

Octane Enhancer

Any substance such as MTBE, ETBE, Toluene, and Xylene that is added to gasoline to increase octane and reduce engine knock.

Octane number

Every brand of Gasoline has an octane rating or number which indicates its ability to resist Knocking. When the numbers were first developed, the researchers found that normal heptane (a Hydrocarbon) had almost no ability to resist Knocking so they gave it an octane number of zero. Then they found that isooctane (also a Hydrocarbon) was very resistant to knocking so they gave it the octane number of 100. To measure a particular sample of Gasoline they discovered when it began to create Detonation. Then they mixed isooctane to heptane to find out what percentage of isooctane created the same results as the sample of gasoline. In United States, there are two methods for determining the octane number depending upon operating conditions. The Research Octane Number (RON) is obtained when conditions are somewhat mild. The Motor Octane Number (MON) is obtained when conditions are somewhat severe and give a much lower number than the RON. The numbers on the gasoline pumps are usually an average of the RON and MON. Usually the pump number is about four numbers less than the RON. Thus if the automobile manufacturer recommends using gasoline with a RON of 91 or more, it would be acceptable to use pump gas rating of 87. The pump number is the Anti-knock index which is half the sum of the RON and the MON.

Also See
Motor octane number
Research octane number

Octane rating

A number used to indicate gasoline's antiknock performance (i.e., self ignition) in motor vehicle engines. The two recognized laboratory engine test methods for determining the antiknock rating, i.e., octane rating, of gasolines are the Research method and the Motor method. To provide a single number as guidance to the consumer, the antiknock index (R + M)/2, which is the average of the Research and Motor octane numbers, was developed. Engines with higher compression ratios require higher octane gasoline.

See also
Pump octane
Motor octane
Octagon number
Research octane number

Octave

Frequency difference between harmonic vibrations; the doubling of the frequency of sound.

Octyl alcohol-ethyl hexanol

Additive in absorption machines that reduces surface tension in absorber.