How to calculate a pressure vs crank angle in 4 stroke petrol engine?
Answers
The mean effective pressure is quite often used to calculate the performance of an internal combustion engine. If the work output is indicated output then it is called indicated mean effect pressure. The highest pressure of the engine cylinder pressure is in TDCF, because this step is need the highest pressure to combustion. The highest pressure is 57.76 bar after ignition at 14.316 crank angle degree. The highest indicated mean effective pressure and brake mean effective pressure is 12.0171 bar and 10.872 bar at both 2 000 rpm engine speed. Before the engine speed is 2 000 rpm the imep and bmep is low and increase until on 2 000 rpm. After the engine speed is over than 2 000 rpm the imep and bmep is go to down. Pumping Mean Effective Pressure (MEP) performance of the gasoline engine is shown in Fig. 6. The highest pumping PMEP for gasoline engine is 0.0357 bar at 1000 rpm engine speed and minimum is 1.7497 bar at 6 000 rpm engine speed. The computational temperature in cylinder as a function of crank angle for a spark ignition is shown in Fig. 7. The highest maximum computational temperature in cylinder for gasoline engine is 2851.40 K at 4 000 rpm engine speed and the lowest maximum computational temperature in cylinder is 2 323.61 K at engine speed 1 000 rpm. The computational burned fuel fraction as a function of crank angle for a spark ignition is shown in Fig. 8. The air-fuel ratio of the engine model performance shown in Fig. 9 above, the air-fuel ratio is high in the engine speed is low and the air-fuel ratio is low in the engine speed is high. The highest of the air-fuel ratio is 12.499 on engine speed 1 000 rpm and the lowest of the air-fuel ratio is 11.6279 on engine speed 6 000 rpm. The trend of air-fuel ratio is decreased if the engine speed is increased. Indicated power of an engine is tells about the health of the engine and also gives an indication regarding the conversion of chemical energy in the fuel into heat energy [11 − 13]. Indicated power is an important variable because it is the potential output of the cycle. Therefore, to justify the measurement of indicated power, it must be more accurate than motoring and other indirect methods of measuring friction power. For obtaining indicated power the cycle pressure must be determined as a function of cylinder volume. It may be noted that it is of no use to determine pressure accurately unless volume or crank angle can be accurately measured. In this model the engine indicated power performance on variation speed shown in Fig. 10. The performance of indicated power the engine model is with variation on engine speed. At engine speed 1 000 rpm the indicated power of engine is low, and if the engine speed increases over 1 000 rpm the indicated power arises until 4 500 rpm. When the engine speed is over than 4 500 rpm the indicated power decreases. The lowest engine indicated power model is 17.12 kW at minimum engine speed 1 000 rpm and the maximum indicated power of the engine model is 77.09 kW at engine speed 4 500 rpm. The brake power of the engine model is shown in Fig. 11. Brake power is usually measured by attaching a power absorption device to the drive-shaft of the engine (any type of brake). The brake power of engine lowest is 16 kW at minimum engine speed 1000 rpm and after that if the engine speed is increased the brake power is increased too until engine speed 4 500 rpm. The maximum brake power of the engine model is 63.76 kW at engine speed 4 500 rpm and after that the brake power decreases. The brake specific fuel consumption is shown in Fig. 12. The model simulation result shown that the minimum brake specific fuel consumption is 288.24 g/kWh at 2 000 rpm. The heat transfer coefficient is shown in Fig. 13. The model simulation result shown that the maximum heat 2 transfer coefficient is 3 048.39 w/m K at 4 000 rpm. Ignition is assumed to occur at a specified crank angle with the instantaneous burn of small specified fraction of the unburned gas. The user specifies the appropriate data such as wall heat transfer area behind the flame and the projected flame area, each one divided by the bore area, as function of the fraction of volume burned. This flame area, together with the evolving turbulence velocity and a specified laminar flame speed are used to determinate the burn rate. The burn rate normalized by fuel mass is shown in Fig. 14. The model simulation result shown that the maximum burning rate is 0.041 1/CA at 3 000 ...
https://www.bing.com/videos/search?q=how+to+calculate+a+pressure+vs+crank+in+4+stroke+petrole+engine&docid=607997188307095112&mid=02FAB44A59A9A5517EE702FAB44A59A9A5517EE7&view=detail&FORM=VIREHT