Title: Multi-cylinder spark-assisted homogeneous charge compression ignition engine balancing control
Authors: Hui Xie; Kang Song; Yu He; Jun Lu
Addresses: State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, China ' State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, China ' State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, China ' State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, China
Abstract: Cylinder-to-cylinder variations (CTCVs) are regarded as one of the most important obstacles to put HCCI combustion into practical application in multi-cylinder engines. In this paper, HCCI combustion is realised in a four cylinder naturally aspired PFI gasoline HCCI engine equipped with variable valve actuation systems through negative valve overlap strategy. CTCVs are observed and explained, and the according balancing strategy is developed. Firstly, cylinder individual lambda control is used for IMEP balancing, by aid of intake air mass model derived from system identification. For improvement, a dynamic lambda lean limit searching strategy is designed through combustion stability observation, thanks to which stable combustion is maintained without the negative effect from IMEP balancing. Secondly, regarding CA50 balancing, a mid-ranging control strategy is proposed for coordinated control of intake-valve closing-timing and spark timing. And finally, this control structure is validated in experiment and proved to work well.
Keywords: multi-cylinder balancing control; intake air mass model; lambda lean limit control; mid-ranging control; homogeneous charge compression ignition engines; HCCI engines; modelling; cylinder-to-cylinder variations; spark timing.
International Journal of Powertrains, 2013 Vol.2 No.4, pp.314 - 335
Received: 31 Mar 2012
Accepted: 11 Feb 2013
Published online: 19 Jul 2014 *