Lista zgłoszonych artykułów

Modern compression-ignition combustion engines are designed exclusively as supercharged engines. Striving to increase the engine\'s mean indicated pressure through supercharging results primarily from the possibility of burning a larger dose of fuel, but also from:

• the possibility of changing the sign of the charge exchange loop area, the value of which can be positive,
• the possibility of improving filling by using flushing with increased valve overlap,
• the possibility of increasing the engine\'s mechanical efficiency, which depends on the quotient of the maximum combustion pressure and the mean indicated pressure. In supercharged engines, the indicated pressure increases more than the maximum pressure.

Compression, which is a measure of the increase in the pressure of the working medium, can be used as one of the criteria for distinguishing and evaluating engines. The aim of the work was to determine the changes in the mean indicated pressure for supercharged compression-ignition engines with different degrees of supercharging. The analyses were carried out by determining the mean indicated pressure of the loop, the mean indicated pressure of the high-pressure part of the loop and the mean indicated pressure of the low-pressure part of the loop.
The objects of the study were medium and high-pressure supercharged engines. The AVL measuring and analytical track (IndiWin program and Indimeter 619 device) was used to measure the pressure in the cylinder. At each of the measurement points, the work done on or by the gas was calculated. Then, the work done in the high- and low-pressure loops was determined. The work done in the high-pressure part was calculated as the difference between the work done in the expansion and compression strokes. On the other hand, the work done on the gas in the low-pressure loop was determined as the difference between the work done during the exhaust and intake. In turn, the values ​​of the average indicated pressure of both loops were calculated as the quotient of the work and the cylinder displacement volume.
Analyses were carried out depending on the load and engine speed. The influence of operating parameters on the pressure values in the high- and low-pressure parts was indicated. An attempt was made to assess the phenomena occurring in the charging process.