Thermodynamic efficiency of small diesel engines.

In summary, the size of a diesel engine does not determine its fuel efficiency. Factors such as compression ratio and turbocharging play a bigger role in determining efficiency. However, larger engines typically have higher combustion volume to surface area ratio and lower specific parasitic losses, making them more thermally efficient.
  • #1
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Could a 10 HP diesel engine be made as fuel efficient as say a 100 HP diesel engine, that is (work done/fuel used). Does thermodynamics prevent a smaller engine from being more efficient?

Thank you for your time.
 
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  • #2
The efficiency of the engine isn't based on it's total power generated, but on other things like the compression ratio and if it's turbocharged or not. A 100hp diesel engine will probably be turbocharged, while its unlikely a 10hp engine would be; turbocharged engines are as a general rule more efficieint than naturally aspirated engines.
 
  • #3
Ignoring engine design considerations (such as compression ratio and turbocharging) for a minute, big engines have two key advantages in terms of efficiency.

- Higher combustion volume to surface area ratio
- Lower specific parasitic losses

The former means that less heat is rejected to radiation and coolant. The latter means that you get more shaft power for a given amount of fuel. Like-for-like, big engines are inherently more thermally efficient.
 

FAQ: Thermodynamic efficiency of small diesel engines.

What is thermodynamic efficiency?

Thermodynamic efficiency is a measure of how well an engine converts heat energy into mechanical work. It is expressed as a percentage and is calculated by dividing the useful work output by the total energy input.

How is thermodynamic efficiency measured?

Thermodynamic efficiency is typically measured in a controlled laboratory setting by using specialized equipment to measure the engine's fuel consumption and power output. This data is then used to calculate the efficiency of the engine.

What factors affect the thermodynamic efficiency of small diesel engines?

The thermodynamic efficiency of small diesel engines can be affected by various factors such as the engine design, fuel type and quality, combustion process, and operating conditions. Improvements in these areas can lead to increased efficiency.

Why is thermodynamic efficiency important for small diesel engines?

Thermodynamic efficiency is important for small diesel engines because it directly impacts the engine's performance and fuel consumption. A higher efficiency means the engine can produce more power while using less fuel, resulting in cost savings and reduced emissions.

How can the thermodynamic efficiency of small diesel engines be improved?

The thermodynamic efficiency of small diesel engines can be improved through advancements in engine design, such as using higher compression ratios and optimizing the combustion process. Additionally, using high-quality fuel and proper maintenance can also contribute to improved efficiency.

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