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This paper discusses research activities at the Technische Universität München on the HCCI combustion process, focusing on the development of a model-based control concept with pressure indication. As a first step sensitivity analyses have been carried out to investigate influences of different injection strategies on the combustion and emission characteristics. An optimal injection strategy has been determined and reasonable control variables and ranges corresponding to this strategy were defined. Comprehensive steady-state measurements have been conducted to detect the engine characteristics. In order to limit the experimental effort, principles of DoE (Design of Experiments) have been used to define a methodological approach in the planning of the measurements. Afterwards a multiple-input multiple-output engine model including boundary models for input settings has been designed out of the measurement results.

The development of today's powertrains focuses on the reduction of CO₂ emissions. Therefore several new technologies for internal combustion engines have been established. A further tendency is the successive electrification of powertrains in hybrid vehicles. However, these trends lead to increasing system costs which are a very important aspect at the market segment of compact cars. At the Institute of Internal Combustion Engines of the Technical University of Munich a drivetrain concept for urban and commuter traffic is under development. It is based on a lean-burn air-cooled two-cylinder natural gas engine which is combined with a hydraulic hybrid system. The paper contains detailed information about the engine as well as the hybrid vehicle powertrain in parallel structure. Particular characteristics and innovations of the hydraulic hybrid system compared to systems known so far are shown.

For the next stage of Homogeneous Charge Compression Ignition (HCCI) engine researches, the development of an engine controller, taking account of dynamics is required. The objective of this paper is to develop dynamic multi input and multi output HCCI engine models and a controller to deal with variable valve lift, variable valve phase, and fuel injection. First, a physical continuous model has been developed. This model mainly consists of air flow models, an ignition model, and a combustion and mechanical model of the engine. The flow models use a receiver model on volumetric elements such as an intake manifold and a valve flow model on throttling elements such as intake valves. Livengood-wu integration of Arrhenius function is used to predict ignition timing. The combustion duration is expressed as a function of ignition timings.