Abstract
Internal combustion engines must meet the increasing demands for higher efficiency, cleaner exhaust gases and better drivability. Model based control is one of the possible solutions to satisfy these demands, with the ability to better control emissions and fuel consumption during transient operation via feed forward control, based on accurate prediction of combustion emissions and calculation of optimum engine parameters without additional mechanical devices. In addition, model based control offers model based research and development with lower development costs compared to traditional map based control systems, as it requires fewer maps to operate. In this paper, an example of a model based control system is given, consisting of a simple combustion model for rapid calculation and prediction of combustion and emissions, and an optimization model incorporating PSO (Particle Swarm Optimization) to calculate the optimum engine parameters from the prediction results. The effectiveness of the system is shown using a 2.2 liter, 4 cylinder, turbo-charged passenger car diesel engine operated under steady state conditions in single injection mode. The intake oxygen concentration and injection timing were optimized via PSO to achieve the minimum NOx emission and maximum torque production. Under the above conditions, a 10% decrease in NOx was achieved while torque was increased by 10%, compared to a multiple injection condition with an equal amount of injected fuel, indicating the possibility of creating an effective model based control system for a passenger car diesel engine.
Keywords: Diesel Engine, Engine Control, Model Based Control, Engine Optimization, PSO (Particle Swarm Optimization)