What is constant pressure cycle?
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What is constant pressure cycle?
In addition, a diesel engine operates on what is referred to as a theoretical “constant pressure cycle,” where fuel is presumed to be supplied as the piston moves down the cylinder on its power stroke at a rate such that the cylinder pressure remains constant during the combustion process.
Why is there constant pressure combustion?
Kamal, Combustion in a constant volume produces higher reaction temperature as compared to the constant pressure combustion. For liquid fuel combustion, the high temperature helps fuel spray and atomization process, thus improves air-fuel mixing and combustion efficiency.
Which engine is constant pressure cycle?
Otto cycle The Otto Cycle is named after Nikolaus Otto (1832–1891, German) who is credited as the first creator of a petroleum fuel based internal combustion engine operating under a four stroke cycle.
Why is it important for Diesel cycle?
The high-speed four-stroke-cycle diesel engine produces superior fuel economy, lower noise factors, and ease of meeting exhaust emissions regulations over its two-stroke-cycle counterpart.
What is the difference between constant volume and constant pressure?
The volume of a gas is directly proportional to its temperature when pressure is constant. The ratio of volume to temperature is constant when pressure is constant. This relationship is known as Charles’ law or Gay-Lussac’s law . a constant pressure process is said to be isobaric ….Summary.
| P = | absolute pressure |
|---|---|
| V = | volume |
What is the basic difference between constant volume cycle and constant pressure cycle?
The basic distinction between the constant volume cycle and the well known constant pressure cycle for gas turbines is the method of heat supply, which necessitates a system of combustion chamber valves to contain the fluid.
Why does Diesel cycle have high efficiency compared to Otto cycle?
3. 6 Diesel Cycle. Although for a given compression ratio the Otto cycle has higher efficiency, because the Diesel engine can be operated to higher compression ratio, the engine can actually have higher efficiency than an Otto cycle when both are operated at compression ratios that might be achieved in practice.
Why is the Diesel cycle called constant pressure cycle?
Diesel cycle is called constant pressure cycle because the heat addition process in diesel cycle is done at constant pressure whereas petrol cycle is called constant volume cycle as here the heat addition is done at constant volume. (Heat rejection in both the cycles is done at constant volume).
How does a constant pressure engine work?
After the piston compresses the air till the top most position, diesel is injected into the compressed chamber. As the compressed air is at high temperature, liquid diesel is burnt into gases and in theory, this combustion is assumed to happen at constant pressure. Hence constant pressure engine.
Why is the formula for a diesel engine so complicated?
The formula is more complex than the Otto cycle (petrol/gasoline engine) relation that has the following formula: The additional complexity for the Diesel formula comes around since the heat addition is at constant pressure and the heat rejection is at constant volume.
Why does the diesel engine take so long to heat up?
It’s like the ideal Otto cycle that had heat addition at constant volume. This assumed that the combustion event of a fixed homogenous charge of fuel and air takes place in an infinitely small amount of time. Where in reality it doesn’t. Because diesel takes a long time to burn and is injected and combusted during the power stroke.