Estimation of trapped mass by in-cylinder pressure resonance in HCCI engines. (January 2016)

• Record Type: Journal Article
• Authors: Luján, José Manuel; Guardiola, Carlos; Pla, Benjamín; Bares, Pau
• Is Part Of: Mechanical systems and signal processing. Volume 66/67(2016)
• Page Start: 862
• Page End: 874
• Publication Date: 2016-01
• Subjects: Trapped mass estimation -- Pressure resonance -- Combustion diagnosis; CAI Controlled autoignition -- CAD Crank angle degrees -- CFD Computational fluid dynamics -- ECU Electronic control unit -- EGR (external) exhaust gas recirculation -- EVO Exhaust valve opening -- HCCI Homogeneous charge compression ignition -- IGR Internal (exhaust) gas recirculation -- IVC Intake valve closing -- MFB Mass fraction burn -- OP Operation point -- RCCI Reactivity controlled compression ignition -- SI Spark ignition -- SNR Signal to noise ratio -- SOC Start of combustion -- STFT Short time Fourier transform -- TDC Top dead center -- VVT Variable valve timing; Structural dynamics -- Periodicals; Vibration -- Periodicals; Constructions -- Dynamique -- Périodiques; Vibration -- Périodiques; Structural dynamics; Vibration; Periodicals; 621
• DOI: 10.1016/j.ymssp.2015.05.016
• Languages: English
• ISSNs: 0888-3270

Abstract

Abstract: High pressure gradients at homogeneous charge compression ignition (HCCI) engines heavily excite the pressure resonance. The pressure resonant frequency depends on speed of sound in the cylinder, and thus on the bulk gas temperature. Present paper profits this relation estimating the trapped mass inside the cylinder. In contrast to other estimation methods in the literature, the presented method is based on the trace of the in-cylinder pressure during the cycle; therefore, it permits a cycle-to-cycle mass estimation, and avoids errors associated with other assumptions, such as heat transfer during compression or initial temperature of the in-cylinder gases. The proposed strategy only needs the pressure signal, a volume estimation and a composition assumption to obtain several trapped mass estimates during one cycle. These estimates can be later combined for providing an error estimate of the measurement, with the assumption of negligible blow-by. The method is demonstrated in two HCCI engines of different size, showing good performance in steady operation and presenting great potential to control transient operation. Abstract : Highlights: A method for inferring the trapped mass from resonance is developed. The few signals used by the method ensure obtaining small sensor errors. The method developed permits one cycle resolution without using flow assumptions. Obtaining many trapped mass measures along a cycle permits an error metric.