Exam Question
What is specific fuel consumption of a diesel engine? Why is it necessary to specify it and how will you check this for the large diesel engine of your vessel. (16)
Class 4 (4th Engineer)
MEKM
📅 Jan 2023
Reference Answer
### 1. Definition of Specific Fuel Consumption (SFC)
Specific Fuel Consumption (SFC) is a primary measure of the prime mover's efficiency in converting the chemical energy contained in fuel into useful mechanical work. It is defined as the mass of fuel consumed per unit of power output over a specific period. It is a critical performance indicator for any internal combustion engine.
- **Expression and Units**: SFC is typically expressed in **grams per kilowatt-hour (g/kWh)**, which is the standard SI unit. It may also be expressed in grams per brake horsepower-hour (g/bhp-hr).
- **Significance**: As stated in the provided reference, SFC is a direct measure of the engine's thermodynamic efficiency. A **lower SFC value indicates a higher thermal efficiency**, meaning less fuel is required to produce the same amount of power. For modern large slow-speed two-stroke engines, a typical value is approximately 160-175 g/kWh.
Specific Fuel Consumption (SFC) is a primary measure of the prime mover's efficiency in converting the chemical energy contained in fuel into useful mechanical work. It is defined as the mass of fuel consumed per unit of power output over a specific period. It is a critical performance indicator for any internal combustion engine.
- **Expression and Units**: SFC is typically expressed in **grams per kilowatt-hour (g/kWh)**, which is the standard SI unit. It may also be expressed in grams per brake horsepower-hour (g/bhp-hr).
- **Significance**: As stated in the provided reference, SFC is a direct measure of the engine's thermodynamic efficiency. A **lower SFC value indicates a higher thermal efficiency**, meaning less fuel is required to produce the same amount of power. For modern large slow-speed two-stroke engines, a typical value is approximately 160-175 g/kWh.
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.
Prepare on Android — MeoMock on Google Play