Cycle-by-cycle estimation of IMEP and peak pressure using crankshaft speed measurements

Article type: Research Article

Authors: Ali, Syed Abbas | Saraswati, Samir^*

Affiliations: Mechanical Engineering Department, Motilal Nehru National Institute of Technology Allahabad, Allahabad, Uttar Pradesh, India

Correspondence: [*] Correspondence to: Samir Saraswati, Mechanical Engineering Department, Motilal Nehru National Institute of Technology Allahabad, Allahabad 211004, India. Tel.: +91 532 2271518;Fax: +91 532 2545341; samirsaraswati811@hotmail.com

Abstract: Cylinder pressure based control of internal combustion (IC) engine uses variables derived from cylinder pressure trace as a feedback input to the engine control and diagnostic systems. Direct measurement of such variables using cylinder pressure sensor is quite expensive. This paper proposes an indirect method of estimating two of such variables namely peak pressure (PP) and indicated mean effective pressure (IMEP) using crankshaft speed measurements. Discrete Fourier Transformation (DFT) is used to transform crankshaft speed fluctuation in time domain to frequency domain. Real and imaginary parts of frequency domain signal, at different harmonics of engine firing frequency, are used as input to multilayer perceptron (MLP). The output being PP and IMEP. Various combinations of inputs starting from signals at first harmonic to signals at first five harmonics are tested. Training and validation of MLP is done using data generated on a test rig consisting of single cylinder engine with eddy current dynamometer. The results show that the MLP is suitable for estimation of cycle-by-cycle values of PP and IMEP for most of the operating points where cyclic variations are within driveability limits.

Keywords: Engine control, combustion parameters, cylinder pressure, neural networks, Discrete Fourier Transform

DOI: 10.3233/IFS-151553

Journal: Journal of Intelligent & Fuzzy Systems, vol. 28, no. 6, pp. 2761-, 2015