Diesel cycle engines combustion process

An ideal Diesel cycle with a compression ratio of 20 and a cut-off ratio of 2 has a temperature of 105°F and a pressure of ISpsia at the beginning of the compression process. Determine (a) the temperature and pressure of the gas at the end of the compression process, (b) the temperature and pressure of the gas at the end of the combustion process, (c) heat added to the engine in the combustion chamber, (d) heat removed from the engine to the environment, and (e) thermal cycle efficiency. 

Combustion in the Otto cycle is based on a constant-volume process in the Diesel cycle, it is based on a constant-pressure process. However, combustion in actual spark-ignition engine requires a finite amount of time if the process is to be complete. For this reason, combustion in the Otto cycle does not actually occur under the constant-volume condition. Similarly, in compression-ignition engines, combustion in the Diesel cycle does not actually occur under the constant-pressure condition, because of the rapid and uncontrolled combustion process. 

The combustion process in internal combustion engines as an isobaric or isometric heat-addition process is oversimplistic and not realistic. A real cycle p-v diagram of the Otto or Diesel cycle looks like a curve (combination of isobaric and isometric) rather than a linear line. Are the combustion processes in the dual cycle more realistic ... 

The Diesel cycle is a compression-ignition reciprocating engine consisting of an isentropic compression process, a constant-pressure combustion process, an isentropic expansion process, and a constant-volume cooling process. The thermal efficiency of the Otto cycle depends on its compression ratio and cut-off ratio. The compression ratio is defined as f max/ f min- The cut-off ratio is defined as — Toombustion off/f min ... 

Solution The air-standard Diesel cycle is the same as the air-standard Otto cycl except that the heat-absorption step (corresponding to the combustion process in th actual engine) is at constant pressure, as indicated by line DA in Fig. 8.10. 

Corrosion inhibitors The conditions that influence the onset of corrosion are the entrainment of atmospheric oxygen, moisture from the combustion of fuel, and stop-start running coupled with temperature cycling. In the marine diesel engine, the problem is exacerbated by contamination with fortuitous saline. Corrosion inhibitors are added specifically to cope with this electrochemical process. These additives operate by creating a physical barrier, in the form of a dense hydrophobic, monolayer of chemisorbed surfactant molecules, which prevent access of the water and oxygen to the metal surface. 

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