Development and Experimental Validation of an Adaptive, Piston-Damage-Based Combustion Control System for SI Engines: Part 2—Implementation of Adaptive Strategies

Alessandro Brusa,Matteo Cucchi,Enrico Corti,Nahuel Rojo,Nicolò Cavina,Jacopo Mecagni,Nicola Silvestri,Davide Moro

doi:10.3390/en14175342

Abstract

This work focuses on the implementation of innovative adaptive strategies and a closed-loop chain in a piston-damage-based combustion controller. In the previous paper (Part 1), implemented models and the open loop algorithm are described and validated by reproducing some vehicle maneuvers at the engine test cell. Such controller is further improved by implementing self-learning algorithms based on the analytical formulations of knock and the combustion model, to update the fuel Research Octane Number (RON) and the relationship between the combustion phase and the spark timing in real-time. These strategies are based on the availability of an on-board indicating system for the estimation of both the knock intensity and the combustion phase index. The equations used to develop the adaptive strategies are described in detail. A closed-loop chain is then added, and the complete controller is finally implemented in a Rapid Control Prototyping (RCP) device. The controller is validated with specific tests defined to verify the robustness and the accuracy of the adaptive strategies. Results of the online validation process are presented in the last part of the paper and the accuracy of the complete controller is finally demonstrated. Indeed, error between the cyclic and the target combustion phase index is within the range ±0.5 Crank Angle degrees (°CA), while the error between the measured and the calculated maximum in-cylinder pressure is included in the range ±5 bar, even when fuel RON or spark advance map is changing.

Highlights

IntroductionOscillations (MAPO) deriving from the estimation of the piston damage admissible in a certain amount of time and the model-based open-loop chain, that allows to accurately manage the combustion phase cycle-by-cycle even under transient conditions
In this work the algorithm was developed considering the availability of an on-board indicating system that provides a knock intensity and a combustion phase index (MAPO and MFB50, respectively)
The novel adaption algorithms based on the analytical formulation of the knock and the MFB50 models are implemented in the controller, for the live adaption of fuel Research Octane Number (RON), and the relationship between the combustion phase and ∆Spark Advance (SA)

Summary

Introduction

Oscillations (MAPO) deriving from the estimation of the piston damage admissible in a certain amount of time and the model-based open-loop chain, that allows to accurately manage the combustion phase cycle-by-cycle even under transient conditions. In this way, the knock intensity threshold is defined as a tangible piston damage index and, outside the range of the knock-limited engine operating conditions, the control algorithm keeps the combustion phase close to the maximum efficiency value, integrating knock and combustion control in a single algorithm

Objectives

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Results

Conclusion