Reference Fuels for Octane Engine

The reference fuels and reagents for octane engine are specified by ASTM D2699 and ASTM D2700 standard test methods.

1. Reference Fuels for Octane Engine:

PRF, isooctane and normal heptane classified as reference fuel grade and meeting the specifications that follow:

• Isooctane shall be no less than 99.75 % by volume pure, contain no more than 0.10 % by volume n-heptane, and contain no more than 0.5 mg ⁄L (0.002 g ⁄U.S. gal) of lead.
• n-heptane shall be no less than 99.75 % by volume pure, contain no more than 0.10 % by volume isooctane and contain no more than 0.5 mg ⁄L (0.002 g ⁄U.S. gal) of lead.
• 80 octane PRF blend, prepared using reference fuel grade isooctane and n-heptane shall contain 80 % ± 0.1 % by volume isooctane.
• Dilute Tetraethyllead (Commonly referred to as TEL Dilute Volume Basis) is a prepared solution of aviation mix tetraethyllead antiknock compound in a hydrocarbon diluent of 70 % (V/V) xylene, 30 % (V/V) n-heptane.
• Toluene, Reference Fuel Grade shall be no less than 99.5 % by volume pure. Peroxide number shall not exceed 5 mg per kg (ppm). Water content shall not exceed 200 mg per kg.
• Check Fuels are in-house typical spark-ignition engine fuels having selected octane numbers, low volatility, and good long-term stability.

2. Reagents for Octane Engine:

Octane Engine Cylinder Jacket Coolant:

Water shall be used in the cylinder jacket for laboratory locations. The resultant boiling temperature shall be 100 °C±1.5 °C (212 °F ±3 °F).

Water with commercial glycol-based antifreeze added in sufficient quantity to meet the boiling temperature requirement shall be used when laboratory altitude dictates. A commercial multifunctional water treatment material should be used in the coolant to minimize corrosion and mineral scale. That can alter heat transfer and rating results.

Octane Engine Crankcase Lubricating Oil:

An SAE 30 viscosity grade oil meeting the current API service classification for spark-ignition engines shall be used. It shall contain a detergent additive and have a kinematic viscosity of 9.3 mm² to 12.5 mm² per s (cSt) at 100 °C (212 °F) and a viscosity index of not less than 85. Oils containing viscosity index improvers shall not be used. Multigraded oils shall not be used.