Jet Engine Control, Implementations

Online line-of-sight (LOS) pyrometer is used on certain jet engines for diagnosis and control functions such as hot-blade detection, high-temperature limiting, and condition-based monitoring. Hot particulate bursts generated from jet engine combustor at certain running conditions lead to intermittent high-voltage signal outputs from the LOS pyrometer which is ultimately used by the onboard digital engine controller (DEC). To study the nature of hot particulates and enable LOS pyrometer functioning under burst conditions, a multicolor pyrometry (MCP) system was developed under DARPA funded program and tested on an aircraft jet engine. Soot particles generated as byproduct of combustion under certain conditions was identified as the root cause for the signal burst in a previous study. The apparent emissivity was then used to remove burst signals. In current study, the physics based filter with MCP algorithm using apparent emissivity was further extended to real-time engine control by removing burst signals at real time (1 MHz) and at engine DEC data rate. Simulink models are used to simulate the performances of the filter designs under engine normal and burst conditions. The results are compared with current LOS pyrometer results and show great advantage. The proposed model enables new LOS pyrometer design for improved engine control over wide range of operating conditions.

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Improved Algorithm for Set Inversion With Application to a Jet Engine Control System

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.1870044 ◽

2004 ◽

Vol 127 (1) ◽

pp. 163-166

Author(s):

P. S. V. Nataraj ◽

A. K. Prakash ◽

S. Srivastava

Keyword(s):

Control System ◽

Robust Stability ◽

Interval Analysis ◽

Speed Control ◽

System Stability ◽

Engine Control ◽

Control Loop ◽

Jet Engine ◽

Engine Control System ◽

Parameter Values

We present an algorithm to characterize the set S={x∊Rl:f(x)>0}=f−1(]0,∞[m) in the framework of set inversion using interval analysis. The proposed algorithm improves on the algorithm of Jaulin et al. (Jaulin, L., Kieffer, M., Didrit, O., and Walter, E., 2001, Applied Interval Analysis, Springer, London). The improvements exploit the powerful tool of monotonicity. We test and compare the performance of the proposed algorithm with that of Jaulin et al. in characterizing the domain of robust stability for the speed control loop of a jet engine. The results of testing show that the proposed algorithm encloses S more accurately, meaning that it gives a larger region of compensator parameter values for which the system stability is guaranteed and a smaller region of the same for which the system stability is indeterminate.

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