Fuel Quality Index Calculators

Fuel Ignition & Engine Protection Parameters - CCAI, CII, EPN & FPII

The Calculated Carbon Aromaticity Index (CCAI), Calculated Ignition Index (CII), Engine Protection Number (EPN), and Problem Fuel Identification Index (PFII) are critical metrics for evaluating the ignition and combustion quality of marine and industrial fuels, particularly residual and heavy fuel oils.

The CCAI assesses fuel ignition quality, with lower values indicating superior combustion properties. The CII is a more advanced index that predicts ignition delay, offering a more refined analysis of combustion performance. The EPN, similar to the Engine Friendliness Number (EFN) used by global testing labs, measures the potential risk a fuel may pose to engine components, helping to protect against wear and deposits. The PFII, akin to the Problem Fuel Identification Number (PFIN) cited by testing labs, identifies fuels that may cause operational issues, such as injector blockages and excessive carbon accumulation, enabling operators to avoid problematic fuel batches. These indices are vital for optimizing engine performance, minimizing maintenance concerns, and ensuring seamless operations.

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CCAI

Calculated Carbon Aromaticity Index

Ignition performance of residual fuels in diesel engines depends on engine type and operating conditions. Research links fuel aromaticity, which relates to carbon in aromatic structures, with ignition behavior, density, and viscosity. The CCAI predicts ignition quality: high CCAI (>870) signals poor ignition, causing incomplete combustion, while low CCAI (<840) indicates good ignition. This is especially relevant for engines using heavy fuel oil, affecting combustion, efficiency, and emissions.

CCAI Value	Interpretations
> 900	Very poor ignition properties
870 - 900	Poor ignition properties
850 - 870	Acceptable ignition properties
830 - 850	Good ignition properties
< 830	Excellent ignition properties

CII

Calculated Ignition Index

The Calculated Ignition Index (CII) estimates the ignition quality of residual fuel oils, used in marine engines, industrial boilers, and power plants. Unlike the cetane index for distillate fuels, CII is tailored for heavier fuels, providing a more accurate prediction of ignition delay. A low CII may cause late combustion, leading to increased wear and unburned fuel deposits. In engines, CII helps optimize combustion timing, minimizing piston ring wear and cylinder oil degradation, improving engine performance.

CII Value	Interpretations
> 40	Excellent ignition
35 - 40	Good ignition
28 - 35	Acceptable ignition
25 - 28	Poor ignition
< 25	Delayed ignition

EPN

Engine Protection Number

The Engine Protection Number (EPN) is a calculated value used to assess engine health by analyzing numerous factors. It serves as a fuel quality indicator, considering both beneficial elements that enhance lubrication and harmful components that may affect performance. A low EPN signals poor fuel quality and increased damage risks, while a high EPN indicates safer fuel. EPN is vital for engines, preventing knocking, scuffing, and reducing maintenance costs.

HFO - EPN Value	VLSFO - EPN Value	Interpretations
> 65	> 60	Excellent engine protection
45 - 65	40 - 60	Good engine protection
< 45	< 40	Poor engine protection

FPII

Problem Fuel Identification Index

The Problem Fuel Identification Index (PFII) evaluates the likelihood of fuel causing engine issues, including piston ring breakage. A high PFII value signifies a greater risk of poor atomization and combustion problems, making it a key indicator of potential operational challenges. By predicting issues such as injector clogging and carbon deposit formation, PFII helps in implementing preventive measures, optimizing maintenance schedules, and reducing costly engine failures.

FPII Value	Interpretations
> 130	Poor engine protection
100 - 130	Average engine protection
30 - 100	Good engine protection
< 30	Excellent engine protection

Fuel Ignition & Stability Parameters - CCN & FWI

The Calculated Cetane Number (CCN) gauges a fuel’s ignition quality, predicting how quickly it ignites in a diesel engine based on its chemical composition. CCN is similar to the Equivalent Cetane Number (ECN), as referenced by global testing labs. A higher CCN leads to smoother engine operation and reduced emissions. The Fuel Worth Index (FWI), akin to the True Worth Index (TWI) used by global testing labs, evaluates a fuel’s overall value by factoring in energy content, cost-effectiveness, and environmental impact. While CCN focuses on ignition and engine performance, FWI assesses the economic and environmental feasibility, helping compare different fuel types, particularly biofuels and alternative sources.

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CCN

Calcualted Cetane Number

The Calculated Cetane Number (CCN) evaluates diesel fuel's ignition quality, determining how easily it ignites under standard conditions. A higher cetane number ensures smoother engine performance, better combustion, and lower emissions, while a lower number may lead to poor ignition, increased emissions, and engine knocking. A CCN above 40 indicates excellent ignition quality, while values between 15 and 40 are good. Below 15 requires attention, with values under 5 signifying very poor ignition quality.

CCN Value	Interpretation
> 40	Excellent ignition quality
15 - 40	Good ignition quality
≤ 15	Below average ignition quality (need attention)
≤ 10	Poor ignition quality (need attention)
≤ 5	Very poor ignition quality (need attention)

FWI

Fuel Worth Index

The Fuel Ignition and Combustion Index (FWI) assesses a fuel’s suitability for engine performance by considering three key factors: Calorific Value (CV), which determines energy content; Calculated Cetane Number (CCN), which reflects ignition properties; and Engine Protection (EPN), which indicates the fuel’s impact on engine wear and maintenance. A higher FWI signifies better fuel quality, with values above 80 considered excellent, 60–80 good, 45–60 acceptable, and below 45 indicating poor suitability for engine use.

CII Value	Interpretation
> 80	Excellent fuel's suitability
60 - 80	Good fuel's suitability
45 - 60	Acceptable fuel's suitability
< 45	Poor fuel's suitability

Fuel Filteration Effectiveness Parameters - FBT & PEDI

Fuel filtration performance is evaluated using two important parameters: Filter Blocking Tendency (FBT) and Purifier Efficiency Determination Index (PEDI). FBT gauges how well a filter captures contaminants without becoming blocked, ensuring consistent fuel flow. PEDI measures how effectively a purifier removes water and solid particles from fuel, preserving its quality. Both parameters play a critical role in ensuring the proper functioning and longevity of engines by maintaining clean fuel and preventing damage from contaminants.

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FBTI

Filter Blocking Tendency Index

The Filter Blocking Tendency Index(FBTI) test measures the pressure drop caused by particulate matter in fuel blocking the filter. It involves passing 300 mL of fuel through a 10μm mesh filter at a constant flow rate of 20 mL/min using a piston-type metering pump, monitoring pressure difference. The test continues until either the pressure reaches 105 kPa or 300 mL of fuel is filtered. Higher levels of impurities, like rust and dust, cause faster filter blockages.

FBT Value	Interpretation
> 2.2	Cleaner fuel with better filterability and lower tendency to block filters
1.25 - 2.2	Fuel with a good filterability
< 1.25	Fuel with a higher likelihood of causing filter clogging

PEDI

Purifier Efficiency Determination Index

The Purifier Efficiency Determination Index (PEDI), expressed as a percentage, measures the effectiveness of a fuel purification system in eliminating contaminants. It indicates how efficiently a purifier removes impurities at a specific flow rate, with higher values reflecting better performance. If not properly monitored, purifier efficiency can fall below 50%, allowing impure fuel to enter engines, pumps, or other systems, potentially leading to damage or decreased performance.

PEDI Value	Interpretation
> 80%	Significant reduction/improvement
50% - 80%	Good reduction/improvement
20% - 50%	Average reduction/improvement
< 20%	Poor reduction/improvement