Effect of instantaneous rotational speed on the analysis of measured diesel engine cylinder pressure data
- 作者：Antonis K. Antonopoulos ; antant@central.ntua.gr ; Dimitrios T. Hountalas dx1961@central.ntua.gr
- 关键词：Cylinder pressure ; Instantaneous engine speed ; Crank angle encoder ; Heat release rate ; Indicated mean effective pressure
- 刊名：Energy Conversion and Management
- 出版年：2012
- 期刊代码：13_01968904
- 类别：pw
- 出版时间：August, 2012
- 卷：60
- 期：Complete
- 页码：87-95
- 文件大小：773 K
摘要
Diesel engine cylinder pressure measurements are widely used in field and lab applications to support among other control, monitoring and diagnostic applications. There are two methods to measure cylinder pressure, the use of a crank angle encoder, which guarantees pressure samples at fixed crank angles, and the use of constant time sampling rate. The last is frequently used due to its simplicity or because of practical restrictions. However, in order to perform thermodynamic calculations it is necessary to attribute a crank angle value to each measured pressure value. But if the in-cycle rotational speed fluctuates and this is neglected, an error will result in the values derived from the processing of the measured cylinder pressure.
For this reason in the present work an experimental investigation is conducted on a single cylinder diesel test engine to identify the aforementioned problem. During the tests cylinder pressure and instantaneous speed were recorded using an accurate crank angle reference. These where then used to simulate the measurement of cylinder pressure digitized using a fixed time step. The comparison of the two cylinder pressure traces and the thermodynamic parameters derived from them, reveals the introduction of an error which depends on engine load and speed.