Ion Current Based Data Driven Control of HCCI - the Key to Improve Pressure Based Control Strategies?

IFAC-PapersOnLine, vol. 56, pp. 4941–4946

Abstract

Homogeneous charge compression ignition (HCCI) is a low-temperature combustion process that can both increase efficiency and reduce pollutant raw emissions. The process is highly dependent on low-temperature kinetics of the chemical reactions that lead to auto-ignition. Due to strong coupling of consecutive combustion cycles stable control of HCCI is a major challenge. Ion current sensors that detect ionization in the combustion chamber can provide information about chemical reactions taking place inside the cylinder. In contrast, model-based HCCI control strategies, which require accurate models that describe the current cylinder state, are often based only on the cylinder pressure. However, low-temperature chemical kinetics are not sufficiently taken into account by only using the cylinder pressure signal. Therefore, the main hypothesis of this paper is that HCCI strongly depends on the chemical state in the cylinder, which cannot be adequately described by the pressure sensor in the cylinder alone. Hence, a conventional spark plug is used to apply an ion current sensor, which is used alongside the pressure sensor. The aim is to use further information about the state of the chemical mixture for the control of the engine. The features derived from the ion current are integrated into an explicit artificial neural network-based controller. The developed control strategies are then compared against a purely pressure-based controller. Using the ion current features, the standard deviation of the combustion phasing CA50 is reduced by up to 42% compared to the pressure-based approach. The experimental results of this work show that the inclusion of the ion current in the controller provides a significant advantage for low temperature combustion control.

Authors 5

1. Julian Bedei corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   Teaching and Research Area Mechatronics in Mobile Propulsion, RWTH Aachen

2. Patrick Schaber corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   Teaching and Research Area Mechatronics in Mobile Propulsion, RWTH Aachen

3. Alexander Winkler corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   Teaching and Research Area Mechatronics in Mobile Propulsion, RWTH Aachen

4. David C. Gordon corresponding

   University of Alberta

   Affiliation as printed

   Department of Mechanical Engineering - University of Alberta, Edmonton, AB, Canada

5. Jakob Andert corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   Teaching and Research Area Mechatronics in Mobile Propulsion, RWTH Aachen