The Cetane Index Calculator is a tool designed to estimate the cetane number of diesel fuel. The cetane number is an important parameter that measures the combustion quality of diesel fuel. A higher cetane number indicates that the fuel will ignite more readily when injected into the engine, which is essential for efficient and smooth engine operation. The Cetane Index Calculator estimates this number based on the fuel’s distillation characteristics and density.
This tool is widely used in the fuel industry for quality control and fuel testing, especially in the absence of laboratory equipment. It helps manufacturers and consumers ensure the fuel meets the necessary specifications for efficient engine performance, reducing emissions and improving fuel economy.
Formula of Cetane Index Calculator
Cetane Index by ASTM D4737-03 (4-variable equation):
This formula requires the density at 15°C and the 10%, 50%, and 90% distillation temperatures. It’s more accurate for modern fuels.
Formula:
CI = 45.2 + (0.0892 * T10) + (0.131 * T50) + (0.0523 * T90) + (0.901 * Density) – (0.420 * (Density)²)
Where:
- T10, T50, T90 = temperatures at which 10%, 50%, and 90% of the fuel has distilled (in °C).
- Density = density of the fuel at 15°C (in kg/m³).
General Terms Related to Cetane Index
Below is a table of general terms people commonly search when discussing cetane number and fuel properties. This table helps to understand the terms without requiring detailed calculations.
| Term | Description |
|---|---|
| Cetane Number | A measure of the ignition quality of diesel fuel. Higher values indicate better ignition properties. |
| T10 (Distillation Temperature) | The temperature at which 10% of the fuel has evaporated. |
| T50 (Distillation Temperature) | The temperature at which 50% of the fuel has evaporated. |
| T90 (Distillation Temperature) | The temperature at which 90% of the fuel has evaporated. |
| Density | The mass per unit volume of the fuel, measured at 15°C. This is important for calculating the cetane index. |
| ASTM D4737-03 | The standard method for calculating the cetane index, based on distillation data and fuel density. |
Example of Cetane Index Calculator
Let’s calculate the Cetane Index using an example.
Assume the following values for a sample of diesel fuel:
- T10 = 120°C
- T50 = 250°C
- T90 = 350°C
- Density = 850 kg/m³ (at 15°C)
Using the formula:
CI = 45.2 + (0.0892 * T10) + (0.131 * T50) + (0.0523 * T90) + (0.901 * Density) – (0.420 * (Density)²)
Substitute the values:
CI = 45.2 + (0.0892 * 120) + (0.131 * 250) + (0.0523 * 350) + (0.901 * 850) – (0.420 * (850)²)
CI = 569.875
So, the Cetane Index for this fuel sample is approximately 569.88.
This estimate helps fuel manufacturers determine if the fuel is within acceptable specifications for engine performance.
Most Common FAQs
The Cetane Index is crucial because it indicates how easily diesel fuel will ignite inside an engine. Fuels with a higher cetane number tend to provide smoother engine operation, better fuel efficiency, and lower emissions.
Yes, the Cetane Index can be calculated using the distillation temperatures and the density of the fuel, as demonstrated in the formula. This allows for accurate estimations without the need for costly laboratory tests.
A higher Cetane Index ensures that the fuel ignites at the right time during the engine cycle. This results in better combustion, reduced knocking, and improved fuel economy. It also contributes to reducing the amount of unburned fuel and harmful emissions.