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Study On Close Loop Control Of A 4-Stroke Gasoline HCCI Combustion Engine

Posted on:2008-02-04Degree:DoctorType:Dissertation
Country:ChinaCandidate:N H ZhouFull Text:PDF
GTID:1102360245492508Subject:Power Machinery and Engineering
Abstract/Summary:PDF Full Text Request
Homogeneous Charge Compression Ignition combustion has the potential of providing better fuel economy and emission characteristics. Therefore, it has been widely researched and is gradually becoming a new combustion mode apart from the original ones. However, it is still confronted with problems in ignition timing control, transient operation and control system. In this paper, the aforementioned problems that occur in the application of an HCCI engine are systematically studied in detail.A CAN-bus-based distributed HCCI control system was designed to obtain close loop control on the fully variable valve actuation (FVVA) HCCI gasoline engine. Meanwhile, a layered management strategy was developed to achieve highly real-time control as well as to simplify the couplings between the inputs and the outputs. The entire control system was stratified into three layers, responsible for load management, combustion phase control and mechanical system control respectively, each with its own specified close loop control strategy. The system is outstanding for its explicit configuration, easy actualization and robust performance.Based on the distributed control system, software and hardware were developed for the primary functioning modules of HCCI engine management unit, injection and ignition control unit, FVVA control unit and in-cylinder pressure acquisition unit. With the single-neural-network-based self-adaptive PID control strategy employed, accurate and effective control of FVVA was achieved, which contributed to the operation control of the HCCI engine. Also, an algorithm of in-cylinder pressure acquisition and real-time analysis was developed, realizing the on-board feedback of combustion condition. Another algorithm to predict the amount of inlet flow was developed based on dynamic recurrent neural network, leading to accurate and rapid control of A/F ratio.Model-based optimization and experiments were employed to investigate the general valve control law when the HCCI engine was operated in steady state. The strategy of combining classical PID and feedforward control was proposed to realize the control of IMEP and CA50 in HCCI mode, and cycle-to-cycle control was achieved due to the high real time of this strategy. Meanwhile, HCCI/SI mode transition control strategy based on managing hybrid heat relese curve was studied. Experimental results show that, with the layered management strategy applied, effective control over HCCI operation becomes possible.A virtual HCCI vehicle simulation platform was established, on which engine operation simulation and road simulation were combined to evaluate the HCCI control strategy in NEDC drive cycle as well as to predict the HCCI engine performance throughout the entire NEDC cycle.
Keywords/Search Tags:HCCI, layered management strategy, distributed control system, mode transition transition, Virtual vehicle simulation
PDF Full Text Request
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