Cetane Index Calculator

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Enter the values to use our basic and advanced Cetane Index Calculator. Read the formula and detailed examples below to know more about the Cetane Index.

The Cetane Index Calculator helps to understand the performance and combustion of diesel fuel engines. In order to know more about Cetane Index, kindly stay with us.

Formula:

The formula is:

$\text{CI} = (454.54 – 1640.6 \times \text{SG}) + (774.74 \times \text{A}) – 0.554$

Variables

Variable	Meaning
CI	Cetane Index (a measure of the ignition quality of diesel fuel)
SG	Specific Gravity of the fuel
A	Aniline point of the fuel (measured in degrees Fahrenheit)

Explain How to Calculate ?

Firstly, determine the specific gravity (SG) of the fuel. Now determine the aniline point (A) of the fuel in degrees Fahrenheit. Next to that you have to multiply the specific gravity by 1640.6 and subtract the result from 454.54. Now, multiply the aniline point by 774.74. And finally, add these results together and subtract 0.554 to obtain the Cetane Index (CI).

Solved Examples :

Example 1:

Given:

Specific Gravity (SG) = 0.85
Aniline Point (A) = 150°F

Calculation	Instructions
Step 1: CI = $(454.54 – 1640.6 \times \text{SG}) + (774.74 \times \text{A}) – 0.554$	Start with the formula.
Step 2: CI = $(454.54 – 1640.6 \times 0.85) + (774.74 \times 150) – 0.554$	Replace SG with 0.85 and A with 150°F.
Step 3: CI = $(454.54 – 1394.51) + 116211 – 0.554$	Multiply SG by 1640.6 and A by 774.74.
Step 4: CI = $-939.97 + 116211 – 0.554$	Subtract 1394.51 from 454.54, then add the result to 116211.
Step 5: CI = $115270.476$	Subtract 0.554 to get the final Cetane Index.

Answer:
The Cetane Index is 115270.476.

Example 2:

Given:

Specific Gravity (SG) = 0.90
Aniline Point (A) = 140°F

Calculation	Instructions
Step 1: CI = $(454.54 – 1640.6 \times \text{SG}) + (774.74 \times \text{A}) – 0.554$	Start with the formula.
Step 2: CI = $(454.54 – 1640.6 \times 0.90) + (774.74 \times 140) – 0.554$	Replace SG with 0.90 and A with 140°F.
Step 3: CI = $(454.54 – 1476.54) + 108463.6 – 0.554$	Multiply SG by 1640.6 and A by 774.74.
Step 4: CI = $-1022.00 + 108463.6 – 0.554$	Subtract 1476.54 from 454.54, then add the result to 108463.6.
Step 5: CI = $107441.046$	Subtract 0.554 to get the final Cetane Index.

Answer:
The Cetane Index is 107441.046.

What is the Cetane Index Calculator?

The Cetane Index Calculator is helpful in estimating the cetane number of diesel fuel based on its physical properties, specifically the specific gravity (SG) and the aniline point (A). The cetane number is a critical measure of the ignition quality of diesel fuel, indicating how readily the fuel will ignite under compression. The higher cetane numbers the better is engine performance, the smoother combustion, and lower emissions.

The cetane number and cetane index both measures the quality of diesel, however, they are to be determined in different way. The cetane index calculation formula D4737 assesses the cetane index by using fuel properties and the cetane number, however, is measured directly using a cetane tester and a cetane combustion equation. While the cetane number involves a physical test, the cetane index is calculated without the need for testing equipment. Understanding the difference between cetane number vs cetane index is very crucial for the assessment diesel fuel performance.

Final Words:

Overall, the Cetane Index Calculation are very essential in order to ensure that your diesel fuel is of well standard in order to meet the requirement of an efficient engine operation.

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