How Can I Compare the Efficiencies of Ideal Diesel, Otto, and Dual Cycles?

In summary, the conversation discusses the comparison of Ideal Diesel, Otto, and Dual cycles with constant specific heats. The main focus is on determining the relationship between compression (r) and efficiency (nth). However, the challenge is finding common inputs that can be used to calculate the efficiency for all three cycles. While temperature and pressure are obvious choices for r, cut off ratio is needed for diesel and dual cycle efficiency and pressure ratio is needed for otto cycle efficiency. The possibility of using a common Qin (heat input) is also mentioned.
  • #1
Altairs
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I want to compare the Ideal Diesel, Otto and Dual cycles with constant specific heats. I am interested in knowing the relationship between r (compression) and nth (efficiency). I am unable to determine the common inputs to all three which can give me the efficiency for all the cycles. r with temperature and pressure is an obvious choice. But I also need cut off ratio to calculate diesel and dual cycle's efficiency and it is not there in otto cycle. And I need pressure ratio for otto's efficiency which is not there in the other two cycles. I was wondering if taking a common Qin (heat input) would do ?

Any suggestions please.
 
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  • #2
I want to compare the Ideal Diesel, Otto and Dual cycles with constant specific heats. I am interested in knowing the relationship between r (compression) and nth (efficiency).

For a simple cold air analysis, you can consult just about any basic thermodynamics text or possibly even wikipedia. For a cold air analysis the efficiency of a otto cycle is a function of the k value of the gas and the compression radio. For a diesel or dual cycle you will need the cut out or cut in ratios. You shouldn't need any Qin for an efficiency calculation.
 

FAQ: How Can I Compare the Efficiencies of Ideal Diesel, Otto, and Dual Cycles?

What is the difference between Diesel, Otto, and Dual Cycles?

Diesel, Otto, and Dual Cycles are all thermodynamic cycles that describe the processes involved in internal combustion engines. The main difference between them lies in the type of fuel used and the combustion process. Diesel cycles use compression ignition, where the fuel is injected into hot, compressed air. Otto cycles use spark ignition, where the fuel is ignited by a spark plug. Dual cycles combine both compression and spark ignition for improved efficiency.

What are the main components of a Diesel, Otto, or Dual Cycle engine?

The main components of a Diesel, Otto, or Dual Cycle engine include a cylinder, piston, valves, fuel injector or spark plug, and a crankshaft. The engine also requires an air intake and exhaust system, as well as a fuel injection or spark timing system.

What are the advantages of each type of cycle?

The advantages of Diesel, Otto, and Dual Cycles vary depending on the application. Diesel cycles are known for their high efficiency and low fuel consumption, making them ideal for heavy-duty vehicles. Otto cycles have a simpler design and are better suited for lighter vehicles. Dual cycles offer a balance between efficiency and power, making them suitable for a wide range of vehicles.

What are the disadvantages of each type of cycle?

Diesel cycles can produce higher levels of emissions and noise compared to Otto cycles. Otto cycles have a lower compression ratio, which leads to lower efficiency. Dual cycles can be more complex and require more maintenance compared to Diesel or Otto cycles.

How are these cycles used in real-world applications?

Diesel cycles are commonly used in heavy-duty vehicles such as trucks, buses, and trains. Otto cycles are used in most passenger cars, motorcycles, and small engines. Dual cycles are used in some high-performance vehicles and in hybrid engines, where they work in combination with an electric motor for increased efficiency.

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