body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
max-width: 800px;
margin: 0 auto;
padding: 20px;
}
.calculator-wrapper {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 25px;
margin-bottom: 40px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.calc-header {
text-align: center;
margin-bottom: 25px;
color: #003366;
}
.input-group {
margin-bottom: 20px;
}
.input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #495057;
}
.input-group input {
width: 100%;
padding: 12px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #003366;
outline: none;
}
.input-row {
display: flex;
gap: 20px;
flex-wrap: wrap;
}
.input-col {
flex: 1;
min-width: 200px;
}
button.calc-btn {
background-color: #003366;
color: white;
border: none;
padding: 14px 24px;
font-size: 16px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
transition: background-color 0.2s;
}
button.calc-btn:hover {
background-color: #002244;
}
.result-box {
background-color: #fff;
border: 1px solid #dee2e6;
border-radius: 4px;
padding: 20px;
margin-top: 25px;
display: none;
}
.result-box h3 {
margin-top: 0;
color: #003366;
border-bottom: 2px solid #003366;
padding-bottom: 10px;
}
.result-item {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #f1f3f5;
}
.result-item:last-child {
border-bottom: none;
}
.result-value {
font-weight: bold;
color: #003366;
}
.article-content {
margin-top: 50px;
padding-top: 20px;
border-top: 1px solid #eee;
}
.article-content h2 {
color: #003366;
}
.tip-box {
background-color: #e8f4f8;
border-left: 4px solid #003366;
padding: 15px;
margin: 20px 0;
}
@media (max-width: 600px) {
.input-row {
flex-direction: column;
gap: 0;
}
}
function calculateFeedRate() {
// Get input values
var power = parseFloat(document.getElementById('enginePower').value);
var rate = parseFloat(document.getElementById('feedRate').value);
var density = parseFloat(document.getElementById('oilDensity').value);
var price = parseFloat(document.getElementById('oilPrice').value);
// Validation
if (isNaN(power) || power <= 0 || isNaN(rate) || rate <= 0 || isNaN(density) || density 0) {
dailyCost = dailyLiters * price;
}
// Display Results
document.getElementById('resHourlyKg').innerHTML = hourlyKg.toFixed(2) + " kg";
document.getElementById('resDailyKg').innerHTML = dailyKg.toFixed(2) + " kg";
document.getElementById('resDailyLiters').innerHTML = dailyLiters.toFixed(2) + " Liters";
document.getElementById('resMonthlyLiters').innerHTML = monthlyLiters.toFixed(2) + " Liters";
var costDisplay = document.getElementById('resDailyCost');
if (dailyCost > 0) {
costDisplay.innerHTML = "$" + dailyCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
} else {
costDisplay.innerHTML = "N/A (Enter price)";
}
document.getElementById('results').style.display = 'block';
}
Understanding Cylinder Oil Feed Rate Calculations
In marine engineering, specifically for large 2-stroke crosshead diesel engines (such as MAN B&W or Wärtsilä), the cylinder oil feed rate is a critical operational parameter. It determines the amount of cylinder lubricating oil injected into the combustion chamber to lubricate the piston rings and liner, as well as to neutralize acidic combustion byproducts derived from the sulfur content in the fuel.
Optimizing this rate is a balance between economy and safety. Too little oil leads to "scuffing," excessive wear, and cold corrosion. Too much oil results in financial waste and can lead to deposits on the piston crown and ring grooves (calcium carbonate deposits).
The Calculation Formula
The calculation is based on the specific feed rate set by the engine manufacturer or the operator based on the fuel sulfur content (often referred to as ACC or Alpha Adaptive Cylinder oil control). The formula to determine the daily consumption is:
Daily Consumption (kg) = (Engine Load [kW] × Feed Rate [g/kWh] × 24 hours) / 1000
To convert this mass into volume (Liters), which is how tank levels are typically measured, you must divide by the density of the oil:
Daily Consumption (Liters) = Daily Consumption (kg) / Oil Density (kg/L)
Key Parameters Explained
- Engine Load (kW): The actual power output at which the engine is running. Cylinder oil dosage is directly proportional to the load. Running at Slow Steaming (lower load) reduces consumption significantly.
- Specific Feed Rate (g/kWh): This is the "dosage" setting. Modern engines typically operate between 0.6 g/kWh and 1.4 g/kWh depending on the BN (Base Number) of the oil and the Sulfur content of the fuel.
- Oil Density: Cylinder oil typically has a density around 0.90 to 0.94 kg/L at 15°C. This is required to convert the calculated mass (kg) into volume (Liters) for tank sounding comparisons.
Why Monitor Feed Rate?
Cylinder oil is one of the most expensive consumables on a vessel after fuel. For a large container ship with a 50,000 kW engine running at a feed rate of 1.0 g/kWh, the daily consumption is 1,200 kg (approx 1,300 Liters). With cylinder oil prices often ranging between $1.50 to $3.00 per liter, slight miscalculations or inefficient feed rates can cost a shipping company tens of thousands of dollars annually per vessel.
Furthermore, accurate calculation allows for the verification of the cylinder lubricator's performance. If the calculated theoretical consumption deviates significantly from the actual tank soundings, it indicates a mechanical fault in the lubrication system or incorrect settings in the control unit.