Laboratory Analyst Training Curriculum
Mod 5 - Octane & Cetane
Module from the Laboratory Analyst Training Curriculum curriculum.
Module 5 — Octane and Cetane Number Testing · Learning Objectives · 1. Differentiate RON (D2699) and MON (D2700) for gasoline antiknock characterization. · 2. Operate CFR engine per standard test conditions for RON/MON. · 3. Run cetane engine (D613) and calculate cetane index (D4737) for distillate fuels. · 4. Interpret (R+M)/2 for U.S. pump specifications and sensitivity (R-M). · 5. Apply QA controls including PRFs, check fuels, and engine maintenance. · Octane & Cetane Methods
| Method | Title | Application |
|---|---|---|
| ASTM D2699 | Research Octane Number (RON) | Gasoline antiknock, lower speed |
| ASTM D2700 | Motor Octane Number (MON) | Gasoline antiknock, higher severity |
| ASTM D2885 | Online IR Octane | Inline blending |
| ASTM D613 | Cetane Number (Engine) | Diesel ignition quality |
| ASTM D6890 | Derived Cetane (IQT) | Faster, small-sample DCN |
| ASTM D4737 | Calculated Cetane Index (CCI) | Estimate from density + distillation |
| ASTM D976 | Cetane Index (legacy 2-variable) | Legacy specs |
| ASTM D7668 | DCN by Combustion Analyzer | Modern DCN alternative |
| CFR Engine — RON Conditions (D2699) | ||
| Parameter | Value | |
| Engine speed | 600 ± 6 rpm | |
| Inlet air temperature | Per barometric chart | |
| Coolant temperature | 212 ± 1.8 °F | |
| Oil temperature | 135 ± 15 °F | |
| Ignition advance | 13° BTDC | |
| Air/fuel ratio | Maximum knock intensity | |
| CFR Engine — MON Conditions (D2700) | ||
| Parameter | Value | |
| Engine speed | 900 ± 9 rpm | |
| Inlet mixture temperature | 300 ± 3.6 °F (149 °C) | |
| Coolant temperature | 212 ± 1.8 °F | |
| Ignition advance | Per compression ratio schedule | |
| Air/fuel ratio | Max knock intensity | |
| Cetane Engine (D613) — Conditions | ||
| Parameter | Value | |
| Engine speed | 900 ± 9 rpm | |
| Coolant temperature | 212 °F | |
| Injection timing | 13° BTDC (fixed) | |
| Ignition delay target | 13° | |
| Reference fuels | n-cetane (100) + HMN (15) | |
| Gasoline Octane Specifications | ||
| Grade | AKI (R+M)/2 | Notes |
| Regular | 87 | Typical U.S. station floor |
| Mid-grade | 89 | Intermediate blend |
| Premium | 91 | West Coast premium |
| Premium | 93 | East Coast / Midwest premium |
| Race / Av gas | 100–108 | Specialty, high-compression |
| Diesel Cetane Specifications | ||
| Product | Cetane Min | Cetane Index Min |
| ULSD No. 2-D S15 | 40 (CN) | 40 (CI) |
| No. 1-D S15 | 40 | 40 |
| EN 590 (Europe) | 51 | 46 |
| Aviation JP-8 | No cetane spec | — |
| Cetane Index (D4737) Formula | ||
| Term | Description | |
| CCI | Calculated cetane index (D4737) | |
| Inputs | Density @ 15 °C, T10, T50, T90 | |
| Use | Estimate CN when engine test not available | |
| Limit | Not valid for cetane improver blends | |
| ◄ Return to Instructions |
Source: Laboratory_Analyst_Training_Curriculum_v1.xlsx · Sheet: Mod 5 - Octane & Cetane
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